Forschungszentrum Karlsruhe
ANKA Instrumentation Book
ANKA
Instrumentation Book
Superconductive undulator installed in the south straight section of ANKA.
Spatial distribution of synchrotron light in the ANKA-IR microscope. The entire intensity is contained in a spot size corresponding to the far infrared diffraction limit.
Focusing elements of a cross compound refractive x-ray lens, produced at the ANKA lithography beamline and tested at the xray fluorescence beamline (Nazmov et al. 2003 ANKA Annual Report, 98-99).
Crystal structure of a self-assembling nanostructure for artificial biomimetic photosynthesis, solved to 0.83 Å resolution at the ANKA-PX beamline (Balaban et al. 2005 Chem. Eur. J., 11, 2267-75; reproduced with permission from Wiley).
Confocal micro x-ray fluorescence maps of a uranium enriched tertiary sediment specimen, measured at the ANKA-FLUO beamline using microstructured compound refractive x-ray lenses. 120 x 120 µm2 maps of Fe, As and U distributions at a depth of 60 µm below the sample surface (Denecke et al. 2004 ANKA Annual Report, 13-14). Internal structure of an insect head (Gyrophaena sp.) measured at the ANKA x-ray topography / tomography beamline. Diameter of head 0.5 mm, resolution 1 µm (Betz et al. 2005, ANKA Annual Report, 72-73).
Publisher:
ANKA Angstroemquelle Karlsruhe, ISS Institute for Synchrotron Radiation, Forschungszentrum Karlsruhe GmbH, a member of the Helmholtz Association, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany applications@anka.fzk.de The ANKA Instrumentation Book is available free of charge October, 1st, 2007 Allowed for individuals and non-profit organizations for non-commercial use only. Quoting from the report in the standard manner with proper referencing is permitted. Jacqueline Heinrich
Publication date: Reproductions:
Editor:
Content
1 2 Preamble ..........................................................................................................................2 ANKA Accelerators and Operation ...................................................................................3 2.1 2.1.1 2.1.2 2.1.3 2.1.4 2.1.5 2.1.6 2.2 3 3.1 3.2 3.3 3.4 4 5 Design of the Accelerators .......................................................................................3 The Injector.......................................................................................................3 The Storage Ring Optics ..................................................................................4 The Magnets of the Storage Ring.....................................................................5 The RF System of the Storage Ring.................................................................5 The Vacuum System of the Storage Ring ........................................................6 The Diagnostics of the Storage Ring ................................................................6 Operation..................................................................................................................7 General Description..................................................................................................9 Insertion Device Technology ..................................................................................10 Development of Superconducting Undulators........................................................14 MARTA...................................................................................................................16
ANKA Insertion Devices ...................................................................................................9
ANKA Control Systems ..................................................................................................18 Beamlines at ANKA ........................................................................................................21 5.1 5.1.1 5.1.2 5.1.3 5.1.4 5.1.5 5.1.6 5.1.7 5.2 5.2.1 5.2.2 5.2.3 5.2.4 5.2.5 5.2.6 5.3 5.3.1 Spectroscopy..........................................................................................................26 FLUO – X-ray Fluorescence Spectroscopy Beamline ....................................27 XAS – X-ray Absorption Spectroscopy Beamline ...........................................31 INE-BL – Beamline for Actinide Research......................................................34 SUL-X – X-ray Beamline for Environmental Research ...................................38 WERA – Soft x-ray analytics facility................................................................41 IR1 – Infrared Beamline for Spectroscopy and Ellipsometry ..........................43 IR2 – Infrared Beamline for Spectroscopy and Microscopy ...........................48 Scattering and Imaging ..........................................................................................50 PDIFF – X-ray Powder Diffraction Beamline ..................................................51 SCD – Single Crystal X-ray Diffraction Beamline ...........................................54 NANO – High Resolution X-ray Diffraction, coming up in 2009 ......................58 MPI-MF Beamline ...........................................................................................64 TOPO-TOMO – X-ray Topography & Tomography Beamline ........................67 IMAGE – X-ray Imaging Beamline (planned)..................................................72 Micro-Fabrication....................................................................................................76 LIGA I, II, III - X-ray Lithography Beamlines ...................................................77
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ANKA User Services ......................................................................................................82 Official Contact, Addresses ............................................................................................84
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1 Preamble
The ANKA - Instrumentation Book describes the current status and significant forthcoming changes of the accelerators, insertion devices and beamlines with their experimental stations at the synchrotron radiation facility ANKA (Angstroemquelle Karlsruhe). ANKA has been designed and constructed by the Karlsruhe Research Center. The Karlsruhe Research Center with some 3,500 employees and 22 institutes is one of the biggest research institutions within the Hermann von Helmholtz Association of National Research Centers. Karlsruhe Research Center is funded jointly by the Federal Republic of Germany and the State of Baden-Württemberg. Operation of the facility and support for users is provided by the Institute for Synchrotron Radiation at the Karlsruhe Research Center. ANKA is fully operational since the beginning of 2002. As a large scale research infrastructure within the Helmholtz Association, ANKA provides beamtime for fundamental and application-oriented research, to users from Germany and from abroad. Beamtime is available upon submission of proposals which are evaluated by external experts in a peer review process. A significant share of the beamtime is provided to industrial customers. The utilization of ANKA by industry or commercial customers was formerly organized by ANKA GmbH and is now being arranged by ANKA Commercial Services, ANKA-COS. Emphasis is put on creating an industry-compatible environment. Full confidentiality to industry is guaranteed. The synchrotron light source is composed of a 500 MeV injector and a 2.5 GeV storage ring. It is operated 4000 hours annually for users with a maximum current of 200 mA at an emittance of 50 nmrad. Three straight sections are equipped with insertion devices, a wiggler W74 (27 periods, 74 mm period length), an undulator U10 (20 periods, 100 mm period length) and a superconducting undulator SCU14 (100 periods, 14 mm period length). Nine beamlines at ANKA with eleven experimental stations are operational. Three of them are devoted to lithography and are installed in a clean room area. The beamlines for analytical services cover techniques from spectroscopy to diffraction and are taking advantage of the large spectral range from IR to hard X-rays emitted by the bending magnets. The Max Planck Institute for Metal Research (Stuttgart) runs a X-ray diffraction beamline, the Institute for Nuclear Waste Disposal of Karlsruhe Research Center operates a beamline for actinide research, and the Institute for Solid State Physics (IFP) of Karlsruhe Research Center a soft X-ray beamline (WERA). One beamline is under commissioning: SUL-X, an X-ray beamline for environmental studies. A second IR beamline, a high resolution X-ray diffraction beamline (NANO), and an imaging beamline (IMAGE) are planned. In Chapter 5, the experimental techniques available at the beamlines are described in detail. Technical beamline parameters are given and are augmented by schematics and technical drawings if appropriate.
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2 ANKA Accelerators and Operation
2.1 Design of the Accelerators
The accelerator complex consists of a 52 MeV microtron as a pre-accelerator, a 500 MeV booster synchrotron and a 2.5 GeV storage ring. The injector has a repetition rate of 1 Hz and the booster current is about 5 mA. Injection into the storage ring is two times a day; a current of 200 mA is accumulated in the storage ring at 500 MeV and then ramped to 2.5 GeV. The lifetime of the stored beam at 2.5 GeV is 20 hours for 150 mA. Figure 2-1 gives an overview of the facility with the injector inside the radiation shield wall.
Figure 2-1: View of the ANKA hall with the accelerator complex. The enclosure in the center houses the microtron and booster synchrotron; the 2.5 GeV storage ring with 110 m circumference is located close to the inner side of the concrete radiation protection wall.
2.1.1
The Injector
Electrons are generated from a diode gun at 70 keV and are injected into a racetrack microtron. The acceleration unit of the microtron is a 5.2 MV linac through which the electrons pass 10 times to pick up the final energy of 52 MeV. The linac has a radiofrequency of 3 GHz and is powered by a 5 MW klystron. The main dipoles of the microtron have a field of 1.2 T. The microtron is shown in Figure 2-2.
Figure 2-2: The 52 MeV racetrack microtron.
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The electrons from the microtron are injected into the booster synchrotron off axis in a multiturn process with one kicker positioned opposite to the injection septum. The optics of the booster synchrotron consists of four pairs of 45° bends and horizontally focussing quadrupoles before and after each bend doublet; vertical focussing is achieved only by the edge fields of the bends. The dipole field is 1 T at 0.5 GeV, the dipole radius is 1.67 m. The quadrupoles have a length of 0.12 m, a bore radius of 38 mm, and a maximum field strength of 6 T/m. Fig. 2-3 shows a photo of the injector and the layout. The booster synchrotron has a circumference of 26.4 m. The acceleration in the booster synchrotron is achieved by a single-cell, 500 MHz, 200 W cavity. The electrons are extracted from the booster synchrotron by a slow bump and a fast kick. For injection into the storage ring the beam in the storage ring is deviated towards the storage ring septum by means of three kickers.
Figure 2-3: Photo and layout of the 500 MeV booster synchrotron.
2.1.2
The Storage Ring Optics
The circumference of the storage ring is 110.4 m. The optics of the storage ring is an eightfold DBA (Double Bend Achromat) with two types of long straight sections. The DBA optics consists of one focusing quadrupole between the two bending magnets of the achromat, and one quadrupole doublet upstream and downstream of the bends. The sextupoles are installed between the bends. Figure 2-4 shows the 100 nm·rad optics with zero dispersion in the straight sections, for injection, and the 50 nm·rad optics for user operation.
Figure 2-4: The optics of the ANKA storage ring: left side the 100 nm·rad optics with zero dispersion in the straight sections, right the 50 nm·rad optics with distributed dispersion.
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2.1.3
The Magnets of the Storage Ring
Sixteen technically identical dipole magnets are installed in the storage ring. The iron length is 2.13 m, the gap is 42 mm, the bending radius is 5.559 m and the nominal field is 1.5 T. Five families of quadrupoles are installed with 8 magnets each; all have the same pole profile with a bore radius of 35 mm. The central quadrupole in the achromat has a length of 0.355 m, all the others 0.285 m, the magnet field strength is around dB/dr = 18 T/m. Two families of sextupoles are installed with 16 vertical and 8 horizontal focussing sextupoles. The sextupoles have an iron length of 120 mm and a magnetic strength of d2B/dr2 = 500 T/m2. Photographs of the storage ring dipole, quadrupole and sextupole are shown in Figure 2-5.
Figure 2-5: The magnets of the storage ring, from left to right: dipole, quadrupole and sextupole.
2.1.4
The RF System of the Storage Ring
The electrons in the storage ring are accelerated by four 500 MHz ELETTRA-type cavities. The cavities have a shunt impedance of R = UC / 2PC = 3.4 MΩ. The cavities are powered by two 250 kW klystrons, the power of which is split in half before being fed into the cavities. The cavities are located in pairs in the small straight sections. A photo of one of the cavity station and the booster cavity is shown in Figure 2-6 (cavities in the storage ring have the same form but a more elaborate cooling and tuning system). The storage ring cavities are tuned both by squeezing the cavity body and by changing the cavity temperature. This allows to select a setting at 2.5 GeV, for which no higher order modes are excited. At injection energy at 0.5 GeV, with minor damping due to radiation, higher order modes are always present. The higher order modes cause instabilities and limit the maximal achievable current.
Figure 2-6: Photo of one storage ring RF station (left) and the ELETTRA-type cavity in the booster (right).
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2.1.5
The Vacuum System of the Storage Ring
The vacuum system of the ANKA storage ring is made from nonmagnetic 316LN stainless steel. The electron beam chamber has an internal width of 70 mm and a height of 32 mm. At a current of 200 mA, a radiation power of 125 kW has to be absorbed. The corresponding gas load of 2·10-6 mbarl/s has to be pumped to maintain a pressure of 10-9 mbar. The chambers in the dipoles and the adjacent multipoles downstream, which receive most of the power and gas load, have ante chambers equipped with lumped absorbers. All other vacuum chambers have distributed in-vacuum absorbers along the outer side of the chamber. Pumping is performed by diode ion pumps (500 l/s close to the lumped absorbers, 150 l/s elsewhere). In total pumps with a nominal pumping speed of 20 000 l/s are installed. Pictures of the dipole vacuum chamber and the lumped absorber are shown in Figure 2-7.
Figure 2-7: Photo of the dipole vacuum chamber (left) and two different absorbers (right).
2.1.6
The Diagnostics of the Storage Ring
The diagnostics of the storage ring comprises measurement of beam position, of current and of tune; furthermore, beam-loss monitors and scraper and SR monitors are installed. 32 beam-position monitor (BPM) stations are used around the ring and are located near the entrance and exit of the dipoles. With the installation of insertion devices additional BPM are available at the entry and exit of the straight sections. The orbit is kept stable to within ±5 µm per user shift. Figure 2-8 shows a photo of the current monitor and the tune exciter.
Figure 2-8: Current monitor and tune exciter.
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2.2 Operation
The storage ring is generally operated at an energy of 2.5 GeV with a typical beam current of 200 mA and a lifetime of around 20 hours. In dedicated shifts, beam is provided at 1.3 GeV for deep X-ray lithography (to obtain a soft spectrum) and infrared applications (to operate at shortest bunch length). Figure 2-29 shows the distribution of beam time. Accelerator operation is presently contributed for 75 % for user operation, 13 % for accelerator development as well as combined accelerator/beamline studies, and 12 % in special users operation. The ratio between scheduled and delivered beam time is typically 95%. The normal mode of operation consists of two injection per day at 8:00 and 18:00 hrs during 24 hours. During one month, the accelerator is typically run for one period of five workdays and one prolonged period of twelve days through the weekend for normal user operation and a further period of five days for special users operation/machine physics (see http://www.fzk.de/anka). Figure 2-30 shows a typical daily run. Table 2-28 presents the main parameters of the ANKA machine.
Figure 2-9: Distribution of beam time between different operating modes during 2006 and 2007.
Figure 2-10: Typical daily run. Current in mA (red), lifetime in hours (green), particle energy in GeV (blue).
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Table 2-1: Main parameters of the accelerator at 2.5 GeV. Parameter Circumference Number of long straight sections Photon critical energy Injection energy End energy Operating electron beam current RF-frequency Relative energy spread Momentum compaction factor Horizontal emittance Horizontal working point Vertical working point Horizontal beta-function, min-max Vertical beta-function, min-max Horizontal dispersion, max Port 5°, hor. beam size, divergence Port 5°, vert. beam size, divergence Port 11.25°, hor. beam size, divergence Port 11.25°, vert. beam size, divergence Straight section, hor. beam size, divergence Straight section, vert. beam size, divergence Dipole magnets Number Deflection angle Field strength Deflection radius degrees T m 16 22.5 1.5 5.559 Unit m keV GeV GeV mA MHz 110.4 4 6.0 0.5 2.5 200 500 9 x 10-4 0.01 50 6.73 2.69 0.8 – 15 2 – 21 0.7 0.3 0.1 0.2 0.1 0.9 0.1 0.19 0.01 0.24 0.01 0.06 0.01
nmrad
m m m mm/mrad (rms) mm/mrad (rms) mm/mrad (rms) mm/mrad (rms) mm/mrad (rms) mm/mrad (rms)
Contact
Erhard Huttel Anke-Susanne Müller Ingrid Birkel Pawel Wesolowski Accelerator control room erhard.huttel@iss.fzk.de anke-susanne.mueller@iss.fzk.de ingrid.birkel@iss.fzk.de pawel.wesolowski@iss.fzk.de +49 (0)7247 82 6181 +49 (0)7247 82 6260 +49 (0)7247 82 6183 +49 (0)7247 82 6063 +49 (0)7247 82 6282
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3 ANKA Insertion Devices
3.1 General Description
In two of the four long straight sections of the ANKA storage ring, insertion devices are in operation. The SUL wiggler (W74) is installed in the North section and the WERA undulator (U10) in the East section. The main technical parameters are summarized in the tables below. A superconducting demonstration undulator SCU14 has been installed. The generated radiation is being characterized using a diagnostics front-end. The calculated spectra of the dipole magnet and the ANKA insertion devices are given in Figure 3-1.
Figure 3-1: Brilliance of ANKA insertion devices in comparison with ANKA dipole magnet.
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3.2 Insertion Device Technology
Three insertion devices are installed at ANKA, the high field wiggler for the SUL-X beamline (Figure 3-2), a 100 mm period length undulator for the WERA beamline (Figure 3-3) and a superconductive demonstration undulator at a diagnostics front-end (Figure 3-4). Details are given in below tables (3-1, 3-2, 3-3).
Table 3-1 SUL-X: wiggler parameters. Period length Type Number of full periods Overall Length Minimum gap Maximum gap Maximum Field 74 mm Permanent magnet, hybrid 27 2m 12.5 mm 250 mm 1.53 T
Figure 3-2: The planar permanent magnet SUL-X wiggler W74 is used both as a source for the X-ray beamline of the SUL and as a damping wiggler for the ANKA storage ring. The SUL-X wiggler can increase the beam life time of ANKA by several hours at 2.5 GeV.
Table 3-2: WERA undulator (U10) parameters. Period length Type Number of full periods Overall length Minimum gap Maximum gap Operating gap range Maximum field 100 mm Permanent magnet, hybrid 20 2.074 m 25 mm > 100 mm 50 - 90 mm 0.9 T
10
Figure 3-3: The planar, permanent magnet undulator U10, a loan of the National Synchrotron Radiation Research Center, Taiwan.
Table 3-3: Parameters of the superconducting demonstration undulator SCU14. Period length Type Number of periods Maximum field Gap 14 mm Superconductive, cryogen-free 100 1.5 T Variable in steps: 5, 8, 12, 16 mm
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Figure 3-4: Superconducting undulator SCU14 in the ANKA storage ring.
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10
14
Measured flux at 650A Calculated flux from field measurement Calculated flux from bending
Phot. /s /mm /0.1% BW
10
13
10
12
10
11
10
10
2
3
4
5
6
7
8
9
10
11 12 E [keV]
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14
15
16
17
18
19
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Figure 3-5: Comparison of the measured and calculated spectra at 2.5 GeV measured with a Si (111) monochromator. The undulator current is 650 A. The measured flux is compared with the flux calculated from the field measurements and the flux from a normal bending magnet at ANKA. All values are normalized to a stored current of 100 mA. The gap is 8 mm, k=0.56. The photon flux is normalized to 100 mA beam current.
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3.3 Development of Superconducting Undulators
Superconducting undulators are being developed at ANKA for applications of variable spectral and variable polarization characteristics. With a suitable modification, a superconducting undulator may as well be operated as a wiggler. This special device allows to vary the current direction from coil to coil. In the wiggler mode the current directions are modified leading to a larger period length and therefore to a larger K-value ( K = 0.934.B[T ].λ [cm] (magnetic field B, undulator period length λu)). The
u
main parameters of the device are summarized in Table 3-4. A planar helical superconducting demonstration undulator for the production of circularly as well as linearly polarized radiation is under development. The magnet field characteristics are changed by varying the current through a set of nested coils (Table 3-5). Model coils of the planar helical undulator are shown in Figure 3-6.
Table 3-4: Parameters of a combined superconducting undulator/wiggler, fixed gap 7 mm. Mode Undulator Wiggler I Wiggler II Wiggler III Period length λu 15 30 45 60 K parameter 2 4 6 8
Table 3-5: Preliminary design parameters of a future superconducting planar helical undulator. The undulator produces both left- and right-handed circularly polarized radiation, as well as horizontal and vertical linear polarization. Period length Type Number of full periods Overall Length Minimum gap Maximum Field 45 mm Superconducting, cryogen-free 20 0.9 m 17 mm 0.55 T
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Figure 3-6: Model of a planar helical undulator. The undulator has two independently powered coils which allow to produce radiation with electrically variable polarization direction.
Figure 3-7: Planned installation of superconductive undulators at ANKA: south SCU14, east planar helical undulator with a period length of 45 mm, west undulator with electrically switchable period length.
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3.4 MARTA
A dipole magnet with tunable spectral characteristics (Figure 3-8) has been designed and named MARTA. MARTA will be used for irradiating larger, variable-thickness resist samples for microsystems technology. The main features of the device are variable field strength and variable length so that the total beam deflection angle remains a constant 50 mrad independent of the field strength. The variable length is obtained by dividing the magnet into sub-magnets which can be switched on independently.
10x10 Phot/s/0.1%bw/mr
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8 6 4 2 0
2 3 4 5 6 78 2 3 4 5 6 78
0.3
0.5 0.7 1 1.5 T
2
3
4 5 6 78
10 eV
100 eV Photon Energy
1keV
10keV
Figure 3-8: Calculated spectra of the MARTA dipole magnet at different field strengths.
Contact
Robert Rossmanith Axel Bernhard Sara Casalbuoni Andreas Grau Barbara Kostka Elena Mashkina Daniel Wollmann robert.rossmanith@iss.fzk.de axel.bernhard@iss.fzk.de sara.casalbuoni@iss.fzk.de andreas.grau@iss.fzk.de barbara.kostka@iss.fzk.de elena.mashkina@iss.fzk.de daniel.wollmann@iss.fzk.de +49 (0)7247 82 6179 +49 (0)7247 82 8368 +49 (0)7247 82 8369 +49 (0)7247 82 6170 +49 (0)7247 82 6004 +49 (0)7247 82 8370 +49 (0)7247 82 6869
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4 ANKA Control Systems
The 2.5 GeV ANKA synchrotron facility at Forschungszentrum Karlsruhe is based on the following standardized and autonomous control systems
Beamline Control (PVSS) Cooling, Air Conditioning (IGSS) RF Control (IGSS) Storage Ring Control (ACS) Beamline Control (Gamma) Beamline Personnel
Safety System (Pilz)
Infrastructure Facilities (IGSS) Insertion Devices (Labview) Radiation Monitoring System Experiment Control (spec)
Storage Ring Interlock (PLC)
The control system of the accelerator (ACS - Advanced Control System) manages around 500 physical devices, like power supplies, vacuum pumps, beam position monitors, and RF generators. The device I/O is handled by self-sufficient micro-controller boards, which connect to a standard LonWorks field bus network. Each branch of the network is attached to a PC with simple device servers running on it. The device servers map the devices and their properties onto approximately 2000 objects and make them remotely available using CORBA. ACS was developed in cooperation with the European Space Organisation. On the client side Abeans completely wrap the CORBA client-side objects. The java based Abeans provide a rich application framework which allows even non-experts to easily build powerful applications. The standard modules allows the operator to set machine parameters or to run automatic applications (like orbit control, cycling and communication with the devicedatabase) and to control the machine parameters which are logged in the SQL database. Spec is the heart of the beamline control systems, the measurement logic of spec is coded in macros using a C-like language. Thus, individual users can easily write their own macros or modify the provided standard macros to meet their particular needs. To control the various beamline components, VME-bus as well as CAN-bus, GPIB-field bus and Ethernet are used. The vacuum control is done over a graphical user interface under the real-time operating system OS/9 (Gamma). All access valves, absorbers and cooling is supervised by a Siemens S7 programmable logic controller (PLC) protecting the beamline components and the vacuum of the ANKA storage ring. The personnel safety at the beamlines (BPSS) is guaranteed by an independent, fail-safe, three-processor PSS3100 PLC, which controls the status of all radiation shutters and the doors of the lead hutches. The safety system is also connected to the machine safety relay and triggers the RF-shutdown in the case of an emergency beam dump request from a beamline.
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The system safety hard- and software is certified. The BPSS control cabinet is located at each beamline and controls the status and error state of all safety components of a beamline. All beamline PSS3100 PLCs are connected via a safety bus to the central PSS3100 cabinet in the ANKA control room. The BPSS status is given to the user in a window on the beamline PC. The Supervisory Control and Data Acquisition Systems (SCADA) are IGSS and the upcoming PVSS. Up to now main parts of the ANKA infrastructure are controlled by the Windows based IGSS. In the end of the year 2006, PVSS II was introduced to integrate all the different autonomous control systems and share the available status-, diagnostic- and alarm- data in the framework of an embedded control system architecture (eCSA) at ANKA.
Insertion Devices Cooling, Air Conditioning RF Control Infrastructure Facilities Beamline Control Experiment Control (spec) TCP/IP Beamline Control (Gamma)
Storage Ring Interlock (PLC) Beamline Personnel
Safety System (Pilz)
Storage Ring Control (ACS) Radiation Monitoring System
Contact
Wolfgang Mexner Karlheinz Cerff Thomas Spangenberg Guido Becker Steffen Pfeifer Hotline wolfgang.mexner@iss.fzk.de karlheinz.cerff@iss.fzk.de thomas.spangenberg@iss.fzk.de guido.becker@iss.fzk.de steffen.pfeifer@iss.fzk.de +49 (0)7247 82 6189 +49 (0)7247 82 6182 +49 (0)7247 82 6130 +49 (0)7247 82 6261 +49 (0)7247 82 6197 +49 (0)7247 82 6614
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5 Beamlines at ANKA
A description of present and planned ANKA beamlines is given in this chapter. It contains information about their purposes, applied methods, instrumentation and planned upgrades. The beamlines are subdivided into spectroscopy beamlines, diffraction and imaging beamlines, and microfabrication beamlines. A summary of the beamlines with some key parameters and their experimental stations is shown in Table 5-1. Technical details of present and planned beamlines are described. Additional data such as flux and characteristics of the beamline optics will be presented separately in the beamline chapters. Figure 5-1 shows the present status of the ANKA hall. Three of the straight sections are equipped with insertion devices: a wiggler for SUL-X, an undulator for WERA, and the superconducting demonstration undulator. Figure 5-2 shows the ANKA hall with the planned upgrades from 2007 to 2009.
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Beamline Ionization chambers, 5 element Ge detector, closed cycle He cryostat, 4 axis goniometer for GI-XAFS Energy range: 2.4 - 27 keV -4 Resolution: 2×10 ∆E/E Dipole magnet Operational
Technical and scientific application
Experimental station
Specification
Source
Status
XAS
Extended X-ray absorption fine structure
(EXAFS)
X-ray absorption near edge fine structure
(XANES), Q-EXAFS Vacuum chamber, SiLi-detector Energy range: 1 - 30 keV -2 Resolution: 2×10 ∆E/E Dipole magnet Operational
FLUO
X-ray fluorescence analysis (XRF), X-ray
fluorescence microprobe (µ-XRF), total X-ray
reflection fluorescence (TXRF)
-1 -1
IR1 IR microscope, liquid He cryostats limited FTIR spectrometer, IR microscope, IR nanoscope, liquid He cryostat Best spectral resolution: 0.1 cm Spatial resolution: diffraction limited (microscopy), 100-1000x beyond the diffraction limit (nanoscopy) Vacuum chamber, ionization axis diffractometer + CCD Energy range: 1.5 - 22 keV (presently 4 – 16 keV) -4 Resolution: 2×10 ∆E/E (for Si crystals) Ionization chambers, 5 element Ge detector, 4 axis goniometer for GIXAFS, liquid N cryostat PEEM, fluorescence detector, electron energy analyzer, SXMCD setup, cryostat, preparation chambers including pulsed laser deposition, UHV sample transfer Energy range: 100 – 1500 eV -4 Resolution: up to 1× 10 ∆E/E Energy range: 2.1 - 25 keV -4 Resolution: 2×10 ∆E/E
-1 -1
nfrared/THz -spectroscopy, Best spectral resolution: 0.1 cm Spatial resolution: diffraction
FTIR spectrometer, ellipsometer,
Spectral range: 4 - 10000 cm
Dipole magnet edge
Operational
-ellipsometry, -microscopy
IR2
Infrared/THz -microscopy and imaging,
Spectral range: 4 - 10000 cm
Dipole magnet edge
Operational 2009
-near field nanospectroscopy
Table 5-1: Operational and planned beamlines and experimental stations (blue: beamlines for microfabrication, red: spectroscopy beamlines, green: scattering and imaging beamlines).
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SUL-X
X-ray diffraction (XRD), fluorescence analysis
Wiggler
Operational 2007
(XRF) and X-ray absorption spectroscopy in µ- chambers, 7 element SiLi-detector, 4
focus
INE-BL
Spectroscopy of actinide samples
Dipole magnet
Operational
WERA
Soft X-ray spectroscopy and microscopy,
photoelectron spectroscopy, SXMCD
Dipole (present) ; dipole and undulator (future)
Operational
Beamline 4+2 circle diffractometer Energy range: 6 - 20 keV -4 Resolution: 2×10 ∆E/E Dipole magnet Operational
Technical and scientific application
Experimental station
Specification
Source
Status
PDIFF
X-ray powder diffraction (XRPD),
(upgraded)
roentgenography, single-crystal diffraction
SCD detector and 2 axis diffractometer with image plate detector, 6 axis diffractometer with NaI point detector (1) High-resolution 6-circle diffractometer; (2) heavy-duty diffractometer; MBE chamber, cryostats, superconducting magnet 2+3 circle horizontal and vertical diffractometer for high load (300 kg) Ultra-precise sample manipulator; automatic sample changer system. 2D detector system; energydispersive detector 4 axis goniometer, tomography stages, stages for 300 mm wafer Scanner Energy range: 2.2 – 3.3 keV Dipole magnet White beam, optional 10
-2 -2
Single crystal diffraction, single / multiple
3 axis diffractometer with CCD-
(former PX)
anomalous dispersion (SAD/MAD)
Energy range: 4 - 20 keV -4 Resolution: 3.5×10 ∆E/E
Dipole magnet
Operational
NANO Resolution: 2·10 to 10
-4 -2
X-ray diffraction (HR-XRD) with highest ∆E/E
Energy range: 3 keV – 30 keV
Superconducting undulator
Planned
angular resolution, anomalous scattering,
coherent scattering
MPI-MF (MPG)
Surface diffraction, XMCD
Energy range: 5 - 20 keV -4 Resolution: 2×10 ∆E/E Energy range: 7 keV- 65 keV Resolution: 10 to 10 ∆E/E
-4
Dipole magnet
Operational
IMAGE
Radiography and tomography
Superconducting combined wiggler/undulator
Planned
Table 5-1 continuation: Operational and planned beamlines and experimental stations .
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Scanner Scanner
TOPO-TOMO
Topography, Tomography, Radiography
∆E/E (2008)
Dipole magnet
Operational Operational
LIGA I
Mask fabrication, patterning of thin
microstructures
LIGA II
Deep X-ray lithography
Energy range: 2.5 – 12.4 keV
Dipole magnet
Operational
LIGA III
Ultra deep X-ray lithography
Energy range: 2.5 – 15.0 keV
Dipole magnet
Operational
Figure 5-1: Beamlines 2007 Insertion devices: Wiggler for SUL-X Undulator for WERA Superconducting demonstration undulator LIGA Spectroscopy IR Spectroscopy X-ray Scattering/Imaging 3 (LIGA I, II, III) 1 (IR1) 5 (XAS, FLUO; SUL-X, INE, WERA) 4 (PDIFF,SCD, MPI-MF, TOPO)
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Figure 5-2: Beamlines: New installations & upgrades 2007 – 2009; red: existing beamlines, some of them will have received major upgrades; green: new installations. New insertion devices: SCU14 superconducting undulator SCUW superconducting combined undulator / wiggler SC-EPU planar helical undulator LIGA: Spectroscopy IR: Scattering/Imaging: FELIG IR2 New: NANO and IMAGE with KNMF; upgrade: PDIFF, SCD, TOPO
KNMF
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5.1 Spectroscopy
FLUO XAS INE-BL SUL-X WERA IR1 IR2 X-ray Fluorescence Spectroscopy Beamline X-ray Absorption Spectroscopy Beamline Beamline for Actinide Research X-ray Beamline for Environmental Research Soft x-ray analytics facility Beamline for Infrared Spectroscopy and Ellipsometry Beamline for Infrared Spectroscopy and Microscopy
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5.1.1
FLUO – X-ray Fluorescence Spectroscopy Beamline
FLUO is a beamline dedicated to X-ray fluorescence analysis. It is situated at a dipole magnet source. Dedication, Scientific Applications X-ray Fluorescence Analysis is a well-established multi-element technique, capable of yielding accurate quantitative information on the elemental composition of materials. Synchrotron radiation X-ray fluorescence analysis (SR-XRF) is one of the few methods which offer sub-femtogram and sub-ppm levels of detectability combined with a completely nondestructive manner of probing and a high level of accuracy. The high degree of linear polarization combined with the high intensity of synchrotron radiation can be effectively used to perform trace-level microanalysis. In general the XRF technique does not require elaborate sample preparation: the sample can be used in its original state, without destruction by the measurement process. This is an important advantage of the method for analysis of precious works of art, as well as for many environmental and biological samples. Besides detailed information about chemical composition and trace element concentrations (microprobe) XRF can also yield valuable information about spatial elemental distribution. An important application of µXRF is the study of small particles where the arrangement of phases and subclusters can be correlated to the processes of creation, alteration and ageing. For example the analysis of radioactive environmental particles is yielding forensic information on nuclear accidents or nuclear weapon testing. A further example of small particles with tell-tale phase composition are geological tectites such as meteor impact ejecta. Spatial information is very important for accessing the bioavailability and thus the hazard potential of toxic or volatile elements in environmental sediments and soils. Using spatially resolved µXRF, toxic element bearing mineral phases can be identified and potential structure-related mobilization processes can be studied. Examples are arsenic bearing silicates in aquifer sediments (Bengal) and uranium in tertiary sediments as model systems for waste disposal. Materials science applications such as the specification and localization of contaminants in high purity materials, or the homogeneity of alloys or thin films on µm length scales benefit primarily from the high sensitivity and accuracy of SR-XRF.
Available Methods, Obtainable Parameters X-Ray Fluorescence Analysis (XRF): X-ray multi-element analysis technique that
o detects trace elements at sub-ppm level (eg. ~10ng/g for Sr in organic matrix, ~1µg/g for Cu in geological matrix) probes the sample in a completely non-destructive manner determines (trace) element concentration with high accuracy (5% at 20µg/g).
o o
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X-Ray Fluorescence Microprobe (µ-XRF): This technique confines the analytical region of the sample being analyzed to a microscopically small area on the surface or even to a small volume element in the bulk. Resolution in the µm range can be attained. Confocal X-Ray Fluorescence Microprobe: A method for obtaining three dimensional elemental distribution on a micrometer scale. In confocal µ-XRF a (polycapillary) lens is placed in front of the detector confining its field of view. This very flexible method allows the recording of elemental maps at different depth levels below the surface with a depth resolution of about 10-20µm. Total Reflection X-ray Fluorescence (TXRF): TXRF is the surface-sensitive variant of X-ray fluorescence analysis that is used either to detect trace impurities on the surface of flat samples (e.g. silicon wafers) or to analyze very small sample masses deposited on a polished substrate. Detection limits as low as 108 atoms/cm2 can be achieved.
Instrumental characteristics
Table 1: Current key parameters of the beamline Energy range Energy resolution [∆E/E] Source Optics 1.5 keV - 33 keV 2x10-2 or white light 1.5 T Bending magnet (EC = 6 keV) Double multilayer monochromator with W-Si multilayers in 2.7nm period Focusing optics: Compound refractive lenses, Poly-capillaries Poly-capillary: 1x1011 ph/s @17 keV (12µm x 12µm) CRL: 2x109 ph/s @ 17 keV (5µm x 2µm) 5 mm (Hor) x 2 mm (Ver) down to 2 µm x 1 µm Vacuum (10-2mbar, inert gas, air) 1 Ionisation chamber, 1 PIN-Diode for monitoring Si(Li)-energy dispersive detector 133 eV average resolution at 5.9 keV, 52 µs shaping time Silicon multicathode detector, 50mm2 area, throughput > 100 kcps SPEC, AXIL, Spectran, MC-simulation (MSIM), newplot, PyMca
Flux at sample position Beam size at sample Experimental setup / sample environment Experimental setup / detectors
Software / Data treatment / Evaluation
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Figure 1: Schematic layout of the FLUO beamline. Figure 2a: Experimental station for XRF with Ionisation chamber and evacuable sample chamber (right). Figure 2b: XRF set-up with large sample (handcoloure d manuscript).
Figure 3a: Compound refractive lens manufactured by LIGA (IMT).
Figure 3b: Micro-XRF setup (confocal).
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Upgrading of the beamline Within the EU-project “Micro-XRF” (2001-2004) the beamline has been optimized for trace element quantification in cooperation with Antwerp University and ESRF beamline ID-18F The accuracy of the set-up will be further improved by installation of an additional beam monitor for the focused incident beam and by a new absolute calibration of the detector efficiency. A novel type of compound refractive X-ray lens based on micro structures of radiation-hard polymer has been developed at the IMT X-ray lithography facilities . Since 2003 the lenses are being continuously improved in a cooperation between IMT, ISS and the ESRF, resulting in reduced beam sizes and increased intensity gain. Currently with the 3rd generation of CRL we have reached a minimal beam size of 1x2µm2 at a gain of 500.
Beamline Scientist / Contact Person
Rolf Simon Christophe Frieh Beamline rolf.simon@iss.fzk.de christophe.frieh@iss.fzk.de 49 (0)7247 82 6174 49 (0)7247 82 6869 49 (0)7247 82 6649
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5.1.2
XAS – X-ray Absorption Spectroscopy Beamline
XAS is an X-ray absorption spectroscopy (XAS) beamline on a dipole magnet source. Due to the high flux the beamline is suited for highly diluted systems in bulk samples. Dedication, Scientific Applications XAS provides essential information about the local atomic geometry and the chemical state of the absorbing atom. The method is element specific and is not restricted to the crystalline phase, but may be used with highly disordered amorphous and liquid samples. A cooperative multidisciplinary scientific program involving ISS and other research groups is established to solve scientific questions in the fields of: Nanomaterials & catalytic systems: There is intense interest in the development of materials with nano-sized dimensions with novel catalytic, energy storage, or macroscopic properties. The Karlsruhe Research Center research group focuses on H-storage materials based on Ticlusters, external groups on catalytic systems as nanostructured traps for SOx, and on Nidoped nano carbon tube systems for tunable magnetic properties. An objective of characterization is to determine the structure and interatomic distances, and the mean oxidation state of atoms in the nanoparticle. The efficiency of new catalytic systems will be studied in-situ by tracking the changes of the chemical state of educts or products using XAS in combination with mass spectrometer. Environmental Sciences: Contamination of the environment is an inevitable consequence of industrial and domestic processes and presents a health hazard and an limitation to the productive use of land. Currently research is focused on Zn release to soils, a problem even from such seemingly harmless objects as electricity pylons, and on sulfuric acidification of surface waters, which leads to mobilization of toxic metals in mining areas. XAS is an extremely important tool in identifying the nature of toxic metals causing the contamination and, thus allowing remedial strategies to be devised. Available Methods, Obtainable Parameters X-ray Absorption Near Edge Structure (XANES): valence and coordination geometry. Extended X-ray Absorption Fine Structure (EXAFS): interatomic distances to 0.02 Å resolution (up to 5-6 Å); coordination numbers, type of nearest neighbors. There are two principal modes of detection: transmission and fluorescence measurements. The transmission technique uses ionization chambers (Figures 2a,b) and the detection limit is determined by the element of interest and the other elements comprising the sample. Typical values are ~5 % by weight. The fluorescence mode is applicable for the study of elements at lower concentrations (detection limit: ~1 mmol/L) and for "thick" samples where transmission does not work. The fluorescence radiation emitted by the sample as a function of photon energy is recorded using an energy dispersive detector (Figures 3a,b). Instrumental Characteristics The XAS beamline spans the energy range from 2.4 to 27 keV. This covers the K-edges from S to Cd, and up to the L-edge of U. The double crystal monochromator design allows exchange of the two parallel mounted Si(111) and Si(311) crystal pairs within minutes. The key parameters of the beamline are summarized in table 1.
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Table 1: Key parameters of the beamline Energy range Energy resolution [∆E/E] Source Optics 2.4 keV - 27 keV (S K edge, U L-edge, Cd K-edge) Si (111): 2x10-4; Si (311): 1x10-4 1.5 T Bending magnet (EC = 6 keV) Double crystal monochromator with two sets of Si crystals, MOSTAB Planar Zerodur mirror to suppress higher harmonics at low energies
Flux at sample position Si(111): 1.0x10+10 ph/s/mm2 @ 9 keV (measured at average current 140 mA) Beam size at sample Sample environment Experimental setup / detectors 20 mm (hor) x 2 mm (ver) down to 1 mm x 1 mm, typical 8 mm x 1 mm Closed cycle He-cryostat (15 K - 320 K, 0.1 K accuracy) 3 Ionization chambers (transmission mode) 2 combined Ionization chambers optimized for XAFS at the low energy range Five element Ge-detector (fluorescence mode) with digital electronic, a view setups: 130 eV average resolution at 24 µs peaking time, max. throughput 6000 count/s 300 eV average resolution at 0.5 µs peaking time, max. throughput 300000 count/s 450 eV average resolution at 0.25 µs peaking time, max. throughput 600000 count/s WINXAS, Viper, XANDA, XAFSmass, GiFeffit, iFeffit, Sixpack, home made data reduction for XANES spectra (linear combination, PCA included)
Software / Data treatment / Evaluation
Figure 1: Schematic layout of the XAS beamline.
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Figure 2a: Ionization chambers for high E transmission XAS.
Figure 2b: Combined ionization- / sample chamber for low E XAS in transmission mode.
Figure 3a: 5 element Ge detector for fluorescence mode.
Figure 3b: Digital amplifier electronic for Ge detector.
Sample environment & scanning modes A multi sample holder with 12 positions (transmission and fluorescence measurements possible) offers advanced automation options. This sample wheel can be adjusted in both directions perpendicular to the beam. For grazing incident measurements a huber goniometer with two additional slits can be used. Besides the step-by-step scanning mode a Q-XAFS mode with 1-5 min per scan is available. Upgrading of the Beamline Together with other ANKA beamlines there will be a development and construction program to provide additional sample chambers for temperature, pressure, humidity and gaseous environments for different in-situ investigations. Contact
Stefan Mangold Ralf Lang Beamline stefan.mangold@iss.fzk.de ralf.lang@iss.fzk.de +49 (0)7247-82 6073 +49 (0)7247-82 3431 +49 (0)7247-82 6647
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5.1.3
INE-BL – Beamline for Actinide Research
The INE-Beamline at ANKA is dedicated to actinide research with emphasis on X-ray spectroscopic techniques. It has been constructed and is operated by the Institute for Nuclear Waste Disposal (INE), FZK. The synchrotron-based activities at the INE-Beamline are embedded in INE’s in-house research, thereby allowing a combination of analytical and instrumental methods, notably laser techniques and microscopic methods. Dedication, Scientific Applications Research and development at INE is largely aimed at long-term safety assessment of proposed deep geological repositories for high-level, heat-producing nuclear waste disposal. To ensure sound safety assessment, a molecular understanding of processes determinant in the fate of radionuclides, notably the actinides, and their thermodynamic quantification is essential. Of central importance in such investigations is determination of actinide speciation, or its molecular, chemical and physical form. Actinide speciation determines its transport properties (mobilization/immobilization), reactivity, bio-availability and, hence, its potential human and environmental risk. X-ray spectroscopic methods have proved to be a valuable tool for actinide speciation research at INE, providing information on the coordination and redox chemistry of actinides, allowing determination and characterization of actinide cations sorbed onto surfaces (e.g., at the mineral - water interface) and investigation of actinide containing precipitates, colloids, and secondary phases, as well as glass and spent fuel corrosion. The INE-Beamline is a so-called pooled facility of the EU European Network of Excellence for Actinide Sciences (ACTINET). Available Methods, Obtainable Parameters Standard methods with monochromatic beam o o o XAFS: XAFS/XRD: XRF: characterization of bulk species correlate phase changes with pair distribution changes measure elemental concentrations
Surface sensitive with grazing incidence (GI) techniques o o o o GI-XAFS: GI-XRD: X-ray reflectivity: TXRF: characterization of surface sorbed species identification of secondary phases on surfaces determination of surface layer thickness and roughness measure elemental depth profiles
Spatial resolution with focused beam for “micro” or µ-techniques o o o µ-XAFS: µ-XRF: µ-XRD: chemical state imaging elemental mapping identification and distribution mapping of phases
Combination of X-ray methods, e.g., XAFS / XRD, or X-ray methods combined with other techniques, e.g., laser spectroscopy
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INE operates an X-ray spectroscopy beamline dedicated to actinide research at ANKA. In situ X-ray spectroscopic investigations on actinide containing samples are routinely performed for studying, e.g., solid-water interface chemical reactions, not possible at other facilities. The unique aspect of the INE-Beamline is that it is in close proximity to INE’s active laboratories on-site. The design is for a multi-purpose beamline, where a number of methods are possible on one and the same sample. Investigations on non-fissile radioisotopes up to 106 times the limit of exemption, contained in two layers of protection, are possible. This amount of activity allows experiments on samples containing, e.g., more than 25 mg long-lived nuclide 237-Np, 242-Pu, 243-Am, or 248-Cm. A special protocol for working with radioactive samples at the INE-Beamline exists and is supervised by INE’s own radiation protection officers for radioactive substances. User operation was commenced in September 2005. A current beamline upgrade involves installation of auxiliary µ-focusing optics allowing spatially resolved techniques. Part of the beamline development is a contractual project with the Physics Institute, Bonn University. Instrumental Characteristics The necessary infrastructure and safety equipment is available at the INE-Beamline for radioactive experiments. The INE beamline offers an energy range from approximately 2.1 keV to 25 keV. This covers the K-edges from P to Pd and the L-edges of lanthanide elements and the lighter actinide elements (up to the Cf L3 edge). The double crystal monochromator (DCM) design has a mechanically coupled movement of the second crystal, while scanning the Bragg angle (Θ), enabling a very fast fixed exit mode for Quick-XAFS studies. Five pairs of DCM crystals are presently available, InSb(111), Si(111), Si(311), Ge(220) and Ge(422). The beamline optics include collimating and focusing Rh coated silicon mirrors for a ~500µm×500µm beam spot at the sample position.
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Table 1: Key parameters of the beamline Energy range Flux Source Optics 2.1 keV - 25 keV (P to Pd K edges, actinides up to the Cf L3 edge) ~3.5×1011 photons/sec at Zr K / Pu L3 edges using Ge(422) 1.5 T Bending magnet (EC = 6 keV) double crystal monochromator, water-cooled first crystal, mechanically coupled movement of the second crystal to ensure fixed exit, MOSTAB, exchangeable crystal pairs InSb(111), Si(111), Si(311), Ge(220), Ge(422) Rh coated silicon mirrors (focusing, collimating) for a ~500µm×500µm beam spot at sample position SESO X-ray beam position monitor • • Standard sample holders for radioactive samples, other dimensions can be accommodated High precision HUBER sample positioning system, goniometer cradles, and auxiliary slits for both standard XAFS and surface sensitive grazing incidence techniques LN2 cryostat (OI OptistatDN) for low temperature measurements 1.2 × 3 m2 breadboard optical table, large enough to accommodate almost any experimental set-up Sealed media feed-through chicanes and separate ventilation / filter system for experimental hutch Access through lock-room with hand / foot-contamination monitor Ionization chambers for nominally high energies (transmission mode) Ionization chambers for nominally low energies setup for total electron yield (TEY) measurements 5 pixel high purity germanium solid state fluorescence detector (Canberra Ultra-LEGe)
Experimental set-up / sample positioning
• • • • Experimental set-up / detectors • • • •
Figure 1: INE-Beamline hutches and optics layout. Yellow (double lined field) marks where work with radioactive samples is allowed.
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Figure 2 (left): Lemonnier-type double crystal X-ray monochromator (DCM) built at the Universität Bonn (Physikalisches Institut). Figure 3 (right): CRL-array provided by FZK-IMT, mounted on top of a PI hexapod positioning stage. In this initial experiment 1-dimensional focusing reduced the vertical dimension of the beam from 350 µm down to ~45 µm.
Upgrading of the INE-Beamline The installation of a compound refractive lens (CRL) set-up together with a 3D sample translation stage and optical microscope will allow x-ray absorption and x-ray fluorescence spectra to be recorded with lateral resolution in the micrometer range. This is especially required for species mapping in heterogeneous samples.
Contact
Boris Brendebach Kathy Dardenne Melissa A. Denecke Jörg Rothe INE-Beamline brendebach@ine.fzk.de dardenne@ine.fzk.de denecke@ine.fzk.de rothe@ine.fzk.de +49 (0)7247-82 4900 +49 (0)7247-82 6669 +49 (0)7247-82 5536 +49 (0)7247-82 4390 +49 (0)7247-82 8295 / 8307
Forschungszentrum Karlsruhe, Institut für Nukleare Entsorgung, P.O. Box 3640, D-76021 Karlsruhe, Germany
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5.1.4
SUL-X – X-ray Beamline for Environmental Research
SUL-X is an X-ray beamline for combined absorption, fluorescence, and diffraction measurements on environmentally relevant materials using a wiggler as source. The beamline is partly in user operation because commissioning is proceeding. Dedication, Scientific Applications Environmental samples are generally complex (e.g., contaminated soils, mining dump sediments), consisting of mixtures of mineral phases (amorphous, crystalline, with micrometer or nano-scale particle sizes), microbes, and in some cases vegetable material. Spatial distribution, speciation, and phase association of trace levels of contaminants are the basis for risk assessment and development of remediation strategies (e.g. arsenic speciation and distribution in groundwater related sediments). The SUL-X beamline will address these issues by providing spatial resolution in the micrometer range with a combination of microfocused techniques (XRF, XAS, XRD). The design of SUL-X was adopted to the needs expressed in 41 letters of intent from 29 national and international future user groups from the environmental science community. Together with a facility for IR spectro-microscopy, it forms the major part of the federal- and state-funded 'Synchrotron Radiation Laboratory for Environmental Studies' (SUL) at ANKA. With the advantages of its concept of combined experimental methods, the SUL laboratory will also benefit proposals from other research fields (e.g., material science, biology). The research is assigned mainly to molecular environmental science (MES), an emerging field that involves studies of chemical and biological processes affecting the speciation, properties, and behavior of contaminants, pollutants, and nutrients in the ecosphere. Synchrotron based techniques are fundamental for MES. A major driving force is the need to characterize, treat, and/or dispose of vast quantities of contaminated materials, including groundwater, sediments, and soils, and to process wastes. Besides high-level nuclear waste significant components come from mining and industrial wastes, atmospheric pollutants, etc., all of which have major impacts on human health and welfare. Addressing these problems requires the development of new characterization and processing technologies – efforts that require information on the chemical speciation of heavy metals, radionuclides, and xenobiotic organic compounds and their reactions with environmental materials. Available Methods, Obtainable Parameters The SUL X-ray beamline will close the spectral gap between soft and hard X-ray spectroscopy, and offers to investigate samples - without remounting them - sequentially with the following methods and modes: o o fluorescence analysis (monochromatic and “white light” mode) absorption spectroscopy (1.5 keV up to 22 keV for Al K-edge to Rh K-edge, U L-edge, presently 4 keV to 16 keV*) diffraction adjustable beam size (down to about 10x10 µm2 size, presently 50x50 µm2*)
o o
* commissioning is in progress to attain the full performance of the beamline.
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Fluorescence analysis with a microfocused beam size will enable elemental mapping of an extended sample (e.g. thin section of a contaminated soil sample), and is very sensitive to low concentrations when a primary “white light” beam with its high flux is used. The wide energy range will allow absorption spectroscopy for all elements between Al and U. XAS provides essential information about the local atomic geometry (EXAFS) and of the chemical state of the absorbing atom (XANES). It can be applied equally to investigate both ordered (crystalline) and disordered (amorphous, liquid) materials. Dilute species and light elements can be measured in the fluorescence mode of XAS. Diffraction experiments (powder and aggregates of crystals) allow the location of pollutant atoms within a crystalline mineral matrix. Adjustable beam dimensions in combination with automated sample-positioning and a precise diffractometer will allow investigation of sample concentrations, chemical states of elements and their associations to mineral phases down to the µm scale, essential key parameters for environmental and health risk assessment. Instrumental Characteristics On the basis of the performance specifications provided by the potential SUL user community the SUL-X beamline should cover an energy range from 1.5 keV to 22 keV combining X-ray absorption spectroscopy, X-ray fluorescence analysis and X-ray diffraction, preferably using a microfocused beam. Based on the detailed technical study, a beamline has been constructed. The main optical elements and calculated key parameters of the beamline are:
Table 1: Key parameters of the beamline Energy range Energy resolution [∆E/E] Source Optics (from source towards experiment) 1.5 keV –22 keV (Al K-edge, U L-edge), presently 4 keV – 16 keV Si(111) 2x10-4; Si(311) 1x10-4; YB66(004) 5x10-4 Wiggler (27 pole each 74 mm) Toroidal mirror, horizontally focusing, vertically collimating DCM with Si(111), Si(311), YB66(400) and mirror (white light) Cylindrical mirror with three coatings, low energy band path, vertically focusing Precise slit in focus, defining a “new” source with adjustable size Elliptical Kirkpatrick Baez mirror system, focusing “new” source Monochromatic or “white light” beam path, selectable 0.5 mm(hor) x 0.3 mm(vert) down to 10 µm x 10 µm (presently down to 50 µm x 50 µm) 4 x 1010 (3x 1010, 6x109) ph / (sx0.1%BWx100mA) in spot size (FWHM) 0.2 mm(hor) x 0.1 mm(vert) (65x40 µm2, 30x20 µm2) at 8 keV Sample diffractometer with theta, phi circle and chi cradle (10°), xyz linear stages CCD detector on 2theta arm for diffraction 3 retractable ionization chambers for absorption 7 element Si(Li) fluorescence detector for fluorescence optical microscope diffractometer and detectors all in vacuum vessel Chambers for different environments (gases, liquids, T-controlled) are foreseen
Beam size at sample position Flux at sample position Experimental station (Scheduled delivery end 2005)
Sample environment
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Figure 1: Schematic layout of the SUL-X beamline. Side view: optics with 3 different beam paths (two are shown); experimental station with versatile sample movement and various detectors.
(5) (6)
(3)
(6) (2) (4)
(3)
(1)
Figure 2a: SUL-X experimental station, View Figure 2b: View into the SUL-X experimental station, towards the incoming beam. Vacuum chamber with with (1) diffractometer, (2) sample holder, (3) control electronics and fluorescence detector (right). ionization chambers, (4) fluorescence detector, (5) CCD detector and (6) light microscope. Dashed line represents primary beam
Milestones o Parallel to user operation ongoing commissioning to attain the full performance end of 2008
Contact
Ralph Steininger Jörg Göttlicher Harald Zöller Beamline ralph.steininger@iss.fzk.de joerg.goettlicher@iss.fzk.de harald.zoeller@iss.fzk.de +49 (0)7247 82 6173 +49 (0)7247 82 6070 +49 (0)7247 82 3329 +49 (0)7247 82 8293 / 8306
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5.1.5
WERA – Soft x-ray analytics facility
WERA (“Weichröntgen-Analytik-Anlage”) is a beamline for soft x-ray spectroscopy and microscopy, owned and operated by the Institute for Solid State Physics (IFP), Forschungszentrum Karlsruhe.
Dedication, Scientific Applications WERA provides important electron spectroscopies in the photon energy range 100 – 1500 eV and combines them in situ with photoemission microscopy. It facilitates combinatory studies of electronic and magnetic structure which have particular promise for strongly correlated, thin-film, and nanoscale materials.
Available Methods, Obtainable Parameters Photoemission, angle-resolved photoemission, resonant photoemission (PES, ARPES, ResPES) – occupied electronic structure, band character, Fermi surface, element-specific band structure Near-edge X-ray absorption (NEXAFS): bulk-sensitive fluorescence yield; total and partial electron yield – unoccupied electronic structure; orbital character, occupation, crystal field strength/symmetry, and spin state; element- and site-specific information Photoemission electron microscopy (PEEM) – imaging of chemical and magnetic contrast; microspectroscopy Soft X-ray magnetic circular dichroism (SXMCD) – element-specific spin and orbital magnetic moments
Instrumental Characteristics
Table 1: Key parameters of the beamline
Energy range Energy resolution [∆E/E] Sources
100 eV - 1500 eV Typically 2x10-4; <1x10-4 demonstrated at N1s absorption edge • • 1.5 T dipole (EC = 6.235 keV), 10 mrad hor., 3 mrad vert. Alternative source (once transfer optics is installed): planar undulator, 20 periods, λm=10 cm (“U10”), on loan from NSRRC, Taiwan.
Optics
Astigmatic Kirkpatrick-Baez (KB) pair of front-end mirrors Quick selection of circular and linear polarization by aperture. Spherical grating monochromator, 3 gratings; movable entrance and exit slits Bendable plane elliptical refocusing mirrors (KB pair) for optimum focus at sample position in all three sequential experimental stations Dipole source, PEEM chamber: typ. 0.4 mm (hor.) x 0.1 mm (vert.) FWHM Ultrahigh vacuum (base pressure 10-11 mbar) PES/NEXAFS chamber: sample temperatures down to 20 K Two UHV chambers for in situ sample preparation; additional PLD chamber with excimer laser and RHEED; all sample transfers in UHV
Beam size at sample Sample / sample environment Experimental setup / sample positioning
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Experimental setup / detectors
• •
• Software / Data treatment / Evaluation
PEEM chamber: photoemission electron microscope (Imaging: <100 nm resol.) PES/NEXAFS chamber: electron energy analyzer (energy resolution 2 meV, angle-resolving, 2D detection), monochromatized He lamp; fluorescence detector (4 elements, ultra-low energy); total and partial electron yield detection; LEED 3rd chamber position for SXMCD chamber or user-specific equipment
User beamline control software spec™ running on Linux system; Windows PCs for experiment control and data evaluation.
all UHV
Figure 1: Schematic layout of the WERA beamline.
Upgrades Undulator transfer optics – for coupling undulator radiation into WERA main optics. Later upgrade of planar undulator to superconducting helical undulator envisioned. SXMCD end station with high magnetic field, to be realized through co-operation with longterm user group.
Contact
Stefan Schuppler Peter Nagel Michael Merz Beamline schuppler@ifp.fzk.de nagel@ifp.fzk.de merz@ifp.fzk.de +49 (0)7247 82 3987 +49 (0)7247 82 6560 +49 (0)7247 82 6635 +49 (0)7247 82 8153 / 8154
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5.1.6
IR1 – Infrared Beamline for Spectroscopy and Ellipsometry
IR 1 is the ANKA synchrotron infrared beamline, it exploits the so-called edge radiation as the source rather than classical synchrotron emission.
Dedication, Scientific Applications Infrared spectroscopy in general covers a huge range of scientific fields: chemistry, physics, biology, astronomy, geology, environment, nanoscience, materials research, forensic science, etc. The infrared beamline focuses especially on the strategic fields of ISS (e.g. condensed matter and materials research, nano technology, earth and environmental research, synchrotron technology). At the same time IR remains open for excellent user science from all fields of research. As an infrared source, synchrotron radiation has five major advantages compared to conventional (black-body) laboratory sources: o o o broader spectral range: continuous from far-IR to the visible higher photon flux in the far-IR higher brilliance: as it is almost a point source the light can be focused down to a diffraction limited size with a gain of up to 3 orders of magnitude pulsed source in the ns range: the light is emitted from electron bunches which allows fast time-resolved measurements (nsec) intense coherent emission in the lower energy part of the far-IR / THz with gain up to 105 compared to conventional synchrotron emission
o
o
Infrared synchrotron radiation fills the spectral gap between sub-millimeter sources and black-body sources, allows imaging at the diffraction limit (few micro meters), ellipsometry and time-resolved spectroscopy including pump-probe experiments. Nowadays extraction of infrared radiation is part of almost all developing programs in existing or planned synchrotron facilities. In parallel to the experimental applications of synchrotron infrared spectroscopy a constant effort is in progress to investigate the fundamental properties of the radiation emitted at IR. The infrared beamline exploits the so-called edge radiation as the source rather than classical synchrotron emission. Since this concept is now being adopted by other synchrotrons, ANKA’s efforts to derive an experimentally verified theoretical description are being followed with great interest by the relevant research community. Current projects include accelerator-based IR-source development, studies of high-Tc superconducting materials, structural organization at the electrode-liquid interface, behavior of matter at extreme pressure, fabrication and subsequent changes in hydrated cementbased materials, fluid inclusions in terrestrial minerals and meteorites as an indicator of geological and astronomical history, metabolic characterization of living human cancer cells, optical properties and conductivity of metal nanowires.
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Available Methods, Obtainable Parameters The infrared beamline is equipped with two main experimental setups. Both are equipped with FTIR spectrometers (Bruker IFS 66v/S) covering a spectral range from 4 to 10,000 cm-1 (0.5 meV to 1.24 eV, 2.5 mm to 1 µm) with a resolution down to 0.1 cm-1. They are equipped with high sensitivity detectors (liquid He-cooled bolometers, liquid N2-cooled MCT (HgCdTe) and InSb detectors, and Si or Ge diodes) and appropriate beamsplitters (Mylar films, multilayer, KBr and quartz). The instruments are evacuated or N2 purged to avoid water and CO2 absorption bands. One interferometer (supplied by MPI-FKF) is equipped with an ellipsometer operating in the domain 4-6,000 cm-1. The ellipsometer operates under vacuum and is provided with an optimized bolometer detector and a liquid He cryostat. Ellipsometry is a technique which allows one to measure the complex dielectric function ε = ε1 + i ε2 of a given material very accurately and with high reproducibility. It measures the change in polarization of light upon non-normal reflection on the surface of a sample to be studied. A typical ellipsometry experiment set-up is shown below (Figure 1a,b).
Figure 1a: Schematic principle of an ellipsometry experiment.
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Figure 1b: The ellipsometric assembly at IR I.
Unlike conventional reflection techniques, ellipsometry requires no reference measurement and no extrapolation of the reflectivity towards zero and infinite energy. This makes ellipsometry measurements more accurate and more reproducible than conventional reflection measurements. The second spectrometer (SUL-IR) is connected to an infrared microscope restricted to the domain 100-10,000 cm-1 (due to diffraction at lower wavenumbers). It is equipped simultaneously with two high sensitivity detectors (liquid N2-cooled MCT or InSb, and a 4.2K bolometer). To avoid interference due to water and CO2 absorption bands it is N2 purged Different objectives are available for transmission and reflection measurements. For sample positioning and mapping a motorized stage with 1µm resolution is used. Sample location and observation using fluorescence in the visible is possible.
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Instrumental Characteristics
Table 1: Key parameters of the beamline. Source Photon beam divergence Optics (extraction and transport) Photon flux (calculated ) Entrance edge of a bending magnet 45 mrad (hor) x 15 mrad (vert) Mirror M1 plane made of Beryllium, M2 toroid, CVD diamond window, M3 toroid, M4 plane, M5/M’5 plane > 1x1013 photons/(s x 0.1% bw)
MPI-IR interferometer (Bruker IFS 66v/S) & ellipsometer Typical beam diameter Wavelength range Energy range Energy resolution Beamsplitters Detectors Ø ≤ 1 mm 2.5 mm – 1 µm 4 – 10,000 cm-1 ≥ 0.5 cm-1 Mylar 125 µm, 50 µm, 25 µm, Si/Mylar, KBr, Quartz Bolometer 1.8K for FIR, bolometer 4.2K for FIR/MIR, MCT for MIR, DTGS (room T) for FIR, DTLaGS (room T) for MIR, Si diode (room T) for NIR/VIS OPUS, Igor Pro
Software/data treatment/evaluation
SUL-IR interferometer (Bruker IFS 66v/S) Typical beam diameter Wavelength range Energy range Energy resolution Beamsplitters Detectors Ø ≤ 1 mm 2.5 mm – 1 µm 4 – 10,000 cm-1 (0.5 meV – 1.24 eV) ≥ 0.1 cm-1 Mylar 50 µm, 6 µm, Si/Mylar, KBr, CaF2 Bolometer 1.8 K for FIR, bolometer 4.2 K for FIR/MIR, MCT (liq. N2) for MIR, DTGS (room T) for FIR, DTLaGS (room T) for MIR, InSb (liq. N2) for NIR, Ge diode (room T) for NIR OPUS, Igor, CytoSpec
Software / Data treatment / Evaluation
SUL-IR microscope (Bruker IRscope II) Typical beam diameter Spatial resolution Wavelength range Energy range Objectives Apertures Detectors Software / Data treatment / Evaluation ≥ 10 µm (at sample, diffraction limited) Diffraction limited (~ ½ wavelength) 100 – 1 µm 100 – 10,000 cm-1 (12.4 meV – 1.24 eV) 15x, 36x Schwarzschild, grazing incidence, ATR (Ge, Si) for IR 4x, 20x, 40x, 100x for VIS ≥ 1 µm Bolometer 4.2 K for FIR/MIR, MCT (liq. N2) for MIR, InSb (liq. N2) for NIR OPUS, Igor Pro, CytoSpec
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Figure 1: Schematic layout of the IR1 beamline.
Beamline Scientists / Contact Person
Yves-Laurent Mathis David Moss Biliana Gasharova Michael Suepfle Beamline yves-laurent.mathis@anka.fzk.de david.moss@anka.fzk.de biliana.gasharova@anka.fzk.de michael.suepfle@iss.fzk.de +49 7247 82-6756 +49 7247 82-2689 +49 7247 82-6178 +49 7247 82-8371 +49 7247 82-6724 / -6854
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5.1.7
IR2 – Infrared Beamline for Spectroscopy and Microscopy (under construction)
Dedication, Scientific Applications IR 2 will be a synchrotron infrared beamline dedicated to studies at micron and sub-micron spatial resolution in condensed matter and materials research, nano science, geo and planetary sciences, environment and synchrotron technology (see also IR 1 beamline description). Available Methods, Obtainable Parameters The infrared beamline IR 2 will be an edge radiation beamline based on the design of IR 1. SUL-IR experimental station for infrared microscopy, currently operated at IR 1, will be moved to the new beamline (see the description of this beamline for further details). Instrumental Characteristics
Source Photon beam divergence Optics (extraction and transport) Photon flux (calculated) Entrance edge of a bending magnet H. 45 mrad x V. 15 mrad Mirror M1 planar made of Beryllium, M2 toroid, M3 toroid, M4 planar, CVD diamond/CaF2 window changer, M5 planar > 1 x 1013 photons/(s x 0.1% bw) SUL-IR interferometer Bruker IFS 66v/S Typical beam diameter Wavelength range Energy range Energy resolution Beamsplitters Detectors Ø ≤ 1 mm 2.5 mm – 1 µm 4 – 10,000 cm-1 (0.5 meV – 1.24 eV) ≥ 0.1 cm-1 Mylar 50 µm, 6 µm, Si/Mylar, KBr, CaF2 Bolometer 1.8 K for FIR, bolometer 4.2 K for FIR/MIR, MCT (liq. N2) for MIR, DTGS (room T) for FIR, DTLaGS (room T) for MIR, InSb (liq. N2) for NIR, Ge diode (room T) for NIR OPUS, Igor Pro, CytoSpec SUL-IR microscope Bruker IRscope II Typical beam diameter Spatial resolution Wavelength range Energy range Objectives Apertures Detectors Software/data treatment/evaluation ≥ 10 µm (at sample, diffraction limited) Diffraction limited (~ ½ wavelength) 100 – 1 µm 100 – 10,000 cm-1 (12.4 meV – 1.24 eV) 15x, 36x Schwarzschild, grazing incidence, ATR (Ge, Si) for IR 4x, 20x, 40x, 100x for VIS ≥ 1 µm Bolometer 4.2 K for FIR/MIR, MCT (liq. N2) for MIR, InSb (liq. N2) for NIR OPUS, Igor Pro, CytoSpec
Software/data treatment/evaluation
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Figure 1: Schematic layout of the IR 2 beamline.
Figure 2a: The IR microscope and the bolometer (FIR detector) at IR I
Figure 2b: Hyperion 3000 IR micro-scope with its focal plane array (FPA) detector temporarily installed at IR I (on loan from Bruker Optics)
The new beamline will incorporate a non turbulent cooling system at the first mirror and related absorbers, and a fast dynamic feedback correction of the photon beam position. We also have funding to deploy the scattering scanning near-field infrared microscopy (sSNIM) technology developed at University of Bochum in order to defeat the diffraction limit and achieve infrared microspectroscopy at nanometer resolution. This would be the first use of a broad-band source for such systems, since until now the University of Bochum group has used only IR lasers. The system would have applications in nano science, materials science, environment, mineralogy and life sciences.
Contact See IR 1 beamline
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5.2 Scattering and Imaging
PDIFF SCD NANO MPI-MF X-ray Powder Diffraction Beamline Single Crystal X-ray Diffraction Beamline High Resolution X-ray Diffraction Beamline , Surface and Interface Scattering Max Planck - Beamline for X-ray Diffraction
TOPOTOMO X-ray Topography & Tomography Beamline IMAGE X-ray Imaging Beamline
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5.2.1
PDIFF – X-ray Powder Diffraction Beamline
The ANKA-PDIFF beamline is a facility for diffraction experiments which require high resolution in both energy and scattering angle. It is optimized in the first instance, but not exclusively, for experiments on polycrystalline materials. Dedication, Scientific Applications While the main use of the beamline is for high-resolution powder diffraction and for residualstress and texture measurements in polycrystalline materials it is also well suited to performing high-resolution scattering studies on single-crystals, epitaxial layers and bulk single-crystalline materials. Typical applications from current user projects include: o In-situ characterization of nucleation and crystallization processes in polymorphic materials, 2-D reciprocal space mapping of epitactic semiconductor layers, Composition and structural characterization of mineralogical phases Microstructure investigations of inorganic refractory and electro-optical materials Residual-stress and texture analysis in functional polycrystalline thin films
o o o o
A majority of these projects make use of the high angular resolution provided by the analyzer-stage (secondary monochromator). Experiments such as texture and in-situ investigations however rely less on high angular resolution and more on the high flux available in the absence of analyzer optics. Available Methods & Measureable Parameters o Symmetric and asymmetric powder diffraction in either reflection (so-called BraggBrentano) or transmission (capillary) geometry. (It should be noted that the diffraction intensity in the case of capillary measurements is dependent upon the sample absorption.) 4-circle scattering experiments with/without analyzer: texture, sin2φ-method,grazing incidence scattering, 1D and 2D reciprocal space mapping Classical structure refinement of atomic coordinates (3D) of small-molecule compounds using conventional 4-circle single-crystal diffraction, also utilizing wavelength-dependent scattering (anomalous diffraction) effects. Microstructure analysis: characterization of residual stresses, particle size determination, texture, film thickness Quantitative phase identification of polycrystalline mixtures
o
o
o
o
The high precision of the diffractometer and the low divergence of the X-ray source also make the instrument suited to the qualification of the X-ray optical properties of ideal 3-D crystalline materials such as monochromators, multilayers etc.
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Instrumental Parameters & Equipment, Infrastructure The PDIFF facility provides focused x-radiation between approx. 6 and 22keV for scattering (diffraction) experiments requiring high energy resolution and high angular resolution. Utilising the available Ge-111 analyser crystal (Si-111 is optionally available) typical linewidths (fwhm) for well-crystallised powders are around 0.02° (about a factor of five better than with a lab. source.) The key parameters of the beamline are summarized in Table 1.
Table 1: Key parameters of the beamline Energy / Wavelength range Energy resolution [∆E/E] Source Monochromator type (double crystal) Flux at sample position Typical beam cross section (fwhm) Experimental setup / sample environment Experimental setup / detectors Software / Data treatment / Databases / Evaluation 6 - 22 keV (without focusing) / 2.1 - 0.5 Å 6 - 18 keV (with sag. focusing) / 2.1 - 0.7 Å ≈ 2x10-4 (at 10 keV) 1.5 T Bending magnet (EC = 6 keV) Si(111) flat crystal pair or Si(111) sagitally focusing 2nd crystal ≈ 1010 photons/(s x 0.1%bw) in 1 mm² @ 10 keV 0.6 mm (H) x 2 mm (V) (focused), 25 mm (H) x 2 mm (V) (unfocused) Diffractometer with 3 sample orientation circles (Ω, Κ, Φ) and 3 detector circles (2θ, θ/2θ analyser stage), all axes with encoder readout NaI-scintillation detector with optionally analyser, slits or Soller collimators for angular resolution ICSD, PDF-2-search-match, TOPAS, SimRef, SHELX, FullProf, Crystallographica,
Figure 1: Schematic layout of the PDIFF beamline (including planned upgrade 2008).
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Figure 2: The diffractometer consists of 3 sample orientation circles (Ω, χ, Φ) and 3 detector circles (2θ, 2 x analyser stage).
Figure 3: heating chamber (MRI) for XRD under vacuum or in gas atmospheres.
Planned Development of the Beamline 2007-2008 The beamline will undergo a major upgrade beginning in autumn 2007. The upgrade will equip the beamine to perform rapid in-situ powder diffraction experiments with a variety of sample environmental options and detector options. The key elements of the upgrade include: 1. both 1D and 2D detectors for rapid time-resolved XRD with moderate angular resolution 2. a heavy-duty 2-circle powder diffractometer with capacity to carry several detectors and heavy sample chambers 3. a multi-crystal-analyser (e.g. 4x) stage for increased throughput for high-resolution experiments. Such detector stages decrease the measuring time proportional to the number of detector channels, but in contrast to linear or 2D detectors, without loss of the high angular and energy resolution offered by crystal optics. 4. vertically focusing mirror optics for compression / collimation of the vertical beam size / divergence to increase the flux at the sample/eliminate remnant vertical divergence. This additional focusing would allow much smaller quantities of materials, especially organics, to be measured. 5. high- and low-temperature sample conditioning for reflection & transmission measurements between approximately –198°C and 1000°C, both in vacuum or in nonoxidising atmosphere, with the option of controlled gas environments for specific experiments
Contact
Stephen Doyle Udo Krieg Beamline stephen.doyle@iss.fzk.de udo.krieg@iss.fzk.de +49 (0)7247 82 6185 +49 (0)7247 82 8372 +49 (0)7247 82 6648 / 6851
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5.2.2
SCD – Single Crystal X-ray Diffraction Beamline
SCD (former PX) is a beamline on a dipole magnet source, dedicated to structure determination of single crystals. Dedication, Scientific Applications The SCD beamline allows structure determination of large crystallized molecules with lattice parameters up to approximately 20 nm. This includes small proteins. The high incoming photon flux and low beam divergence allow taking data from small or weakly diffracting crystals or with higher resolution. Sample sizes typically range between (0.1 mm)³ and (0.5 mm)³, but structures have been derived from crystals as small as 20 µm x 20 µm x 250 µm. As the energy of the radiation incident onto the sample is tunable over a wide energy range by means of a monochromator, application of the MAD (Multiple Anomalous Diffraction) method for phase determination is feasible. ANKA SCD is used to address scientific questions such as: Crystal structure determination: Knowledge of the structure is a key to understanding the properties of nanoscaled materials, such as artificial self-assembling porphyrins, semiconductor cluster crystals, or high-nuclearity transition-metal aggregates.
b a
c
Figure. 1: Crystal Structure of 5hydroxyethyl-15acetyl-Zn-Por.
The synthesis and structure investigation of self-assembling porphyrins mimicing chlorosomal bacteriochlorophylls is a potential major design step towards artificial antennae capable of harvesting sunlight.
Zn N C H O
As for semiconductor cluster crystals, the detailed knowledge of the cluster structure allows in connection with other physical measurements for the establishment of correlations of structure and properties. High-nuclearity transition-metal aggregates may have magnetic properties intermediate between those of small finite aggregates and extended solids. Magnetic interactions can depend critically on metal-ligand bond lengths and angles within the bridges between the metal centers. By determining such geometries to a good level of precision the structure and magnetic behaviour can be correlated. Making use of the instrument capability to measure bragg reflections with high redundancy, it has been demonstrated at ANKA-SCD that the anomalous signal of Sulfur in cubic Insulin is sufficient to determine scattering phases and derive the electron density map with SAD at an incoming wavelength as short as 0.1 nm.
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Soft condensed matter: At SCD, Wide-Angle X-Ray Scattering has already been applied to obtain information about the crystalline state in Polymers (Polyamide, Polyethylene, UHMWPE) as a function of the external parameters temperature or strain in situ. UHMWPE for example is a unique polymer with outstanding physical and mechanical properties and is used in orthopedics implants. The aim of the studies is a better understanding of structure formation and thereby help to improve material properties like e.g. wear resistance. Available Methods, Obtainable Parameters o Single Crystal Diffraction (SCD): Yields electron density maps and atomic coordinates within the asymmetric unit of the unit cell of a single crystal. Single / Multiple Anomalous Dispersion (SAD/MAD) to determine the scattering phases from the anomalous signals of heavy atoms in vicinity of absorption edges Wide Angle X-Ray Scattering (WAXS) to derive pair distribution functions of soft condensed matter. WAXS, particularly suited for the investigation of structural properties of polymers, provides information about order within the crystalline regions of a sample and about the fraction of crystalline material. Reciprocal Space Mapping, X-Ray Reflectometry, Grazing Incidence Diffraction, Grazing Incidence Small Angle Scattering and similar methods for the study of surface and interface structure are currently under commissioning using the 6-circle diffractometer.
o
o
o
Instrumental Characteristics The SCD beamline offers the energy range from 4 keV to 20 keV. This covers the K-edges from Ti to Mo, and L-edges from I to U, enabling Multiple Anomalous Dispersion (MAD) phasing with the most common heavy atom derivates, e.g. Se, Br, Hg, Au, Ag, Pt, W, Zn, Fe. An X-ray mirror with bending mechanism and a sagittally bent 2nd crystal allow focusing the beam on the sample crystal in both directions. Three end stations are available, one six-circle diffractometer with point detector (permanent loan from the University of Karlsruhe), one with a CDD-Detector and one with an image plate for large area exposure.
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Table 1: Key parameters of the beamline. Energy range Energy resolution [∆E/E] Source Optics Beam size at sample Flux at sample position Experimental setup / sample stage Experimental setup / sample environment Experimental setup / detectors 4 keV - 20 keV → Ti to Mo K-edge, I to U L-edge1 Si (111): 3.5 10-4 @ 9 keV 1.5 T Bending magnet (EC = 6 keV) Flat Rh coated Si mirror with bending mechanism, double crystal monochromator with bender on the 2nd crystal Approx. 2 mm (hor) x 1 mm (ver), depending on focusing conditions Si(111): 3x10+10 ph/s/0.1%bw in 1 mm² @ 9 keV one 6-circle diffractometer with NaI point detector two diffractometers with ω, fixed χ, φ - circles N2 cryo cooler (80 K - 400 K, 0.1 K accuracy, Oxford Cryosystems) Ø 340 mm Image Plate (STOE IPDS 2) 62 mm x 62 mm CCD ( < 2 sec.total read time, (60 µm)² resolution, Bruker AXS SMART APEX) Energy resolving SDD for fluorescence scans, 140 eV resolution @ 5.9 keV (Ketek AXAS) X-AREA, X-RED, X-SHAPE, SMART, SAINT, SADABS, XPREP, SHELXTL, CHOOCH, GADDS
Software / Data treatment / Evaluation
Figure 2: Schematic layout of the SCD beamline (former PX).
1
Intensity drops considerably on both ends of the spectrum, below about 6 keV due to air and window absorption and above
about 17 keV due to limitations of the DCM crystal bending radius and the bending magnet spectrum.
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Figure 3: Beamline optical components
Figure 4: Experimental end station CCD
Figure 5: Experimental end station with image plate
Upgrading of the beamline The 6-circle diffractometer shall be equipped with an analyzer stage, a mount for an area detector and flight tubes for SAXS/GISAXS in the near future.
Contact person
Gernot Buth Volker Heger Beamline gernot.buth@iss.fzk.de volker.heger@iss.fzk.de +49 (0)7247 82 6185 +49 (0)7247 82 3313 +49 (0)7247 82 6723
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5.2.3
NANO – High Resolution X-ray Diffraction and surface & interface scattering beamline coming up in 2009
NANO is a future high-resolution X-ray diffraction (HR-XRD) and surface diffraction beamline on a superconducting undulator source. Due to the high flux, small source size and reasonable coherence length, the beamline will be well suited for diffractometry with high angular resolution as well as for anomalous scattering and coherent scattering methods. Dedication, Scientific Applications X-ray diffraction probes the spatial arrangement of atoms in a crystal lattice. It is sensitive not only to chemical compositions and lattice parameters, but also to strain and strain distributions, lattice defects, dislocations, as well as to the shape, size and distribution of surface nanostructures. Since the advent of synchrotron radiation, the range of applicability has been extended from bulk crystals to thin films and multilayers, epitaxial superlattices, nanostructures and nanocrystalline materials, and even to magnetic structures and multilayers. Rapid methodical developments in the last decade have exploited X-ray polarization, anomalous scattering and coherence effects to increase contrast and resolution and to facilitate data analysis. NANO will progressively make the most advanced X-ray diffraction and scattering methods available for internal and external users Structure parameters of interest include lattice parameters, chemical compositions, layer thicknesses, surface and interface roughness, inter-diffusion, crystal lattice quality / homogeneity, strain distributions, nanostructure geometry (size/shape/correlations), nano-porosities and magnetic properties. Thin films and multilayers (amorphous, polycrystalline or single-crystalline) of metals, oxides, polymers, composites and mixed systems: The physical and chemical properties of thin film systems (such as corrosion, activation and passivation) depend on structural features such as layer geometries, residual strain/stress, interdiffusion profiles and interface roughnesses, which can be comprehensively characterized by a combination of X-ray scattering methods. Epitaxial crystalline nanostructures (semiconductor and metallic): Nanostructured systems display electronic quantum effects which are highly attractive for applications e.g. in microelectronics and optoelectronics. The desired function depends on the accurate realization of the intended sample structure. This is a crystal growth problem, whose outcome is in turn determined by the growth parameters. Further optimization of growth technologies and the development of new device concepts depend on precise structural characterization facilities, which are offered by X-ray diffraction methods. Magnetic systems: Magnetic semiconductors combine the properties of semiconductors and ferromagnets. This makes them highly attractive for applications in spintronics, where the spin degree of freedom of the electron is exploited in addition to its charge. Many fundamental and technological questions remain to be answered, such as how to achieve semiconductor ferromagnetism at or above room temperature. X-ray magnetic scattering promises to elucidate structural questions related to these problems. The perspectives for performing magnetic dichroism and/or genuine magnetic scattering measurements at ANKA are currently being evaluated.
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Available Methods, Obtainable Parameters o High-resolution X-ray diffraction (HR-XRD), rocking curve measurements, reciprocal space mapping: geometric structure of crystalline systems on length scales between 1Å and several µm; stress, strain and strain distributions; shape, size, compositional profiles and positional correlations of surface and buried nanostructures. o Surface scattering, crystal truncation rod scattering, grazing incidence diffraction: Studies of crystal surfaces and near-surface layers, thin surface films; surface reconstructions; inplane strains; evolution of strains / compositions with depth below the surface. o X-ray specular reflectivity, non-specular reflectivity, grazing-incidence small-angle scattering (GI-SAXS), truncation rod scattering: for studies of surfaces and layered systems in view of layer thickness, composition, surface and interface roughness, size and distribution of internal inhomogeneities. o
o
X-ray diffuse scattering: for the assessment of various types of crystal defects.
Diffraction anomalous fine structure (DAFS): for the selective study of local structure of selected atomic species at interfaces.
o X-ray magnetic circular dichroism: possible also X-ray magnetic scattering (suitability is currently under consideration)
o Powder diffraction: texture analysis, residual stress analysis for Investigation of polycrystalline systems, nanoporous layers, o Small-angle X-ray scattering: well suited for the investigation of nanoparticles systems; nanocomposites and hybrid materials and it enables to determine the size, shape and distribution and correlation between the particles. o Materials to be investigated include metals, semiconductors, oxides, dielectrics, and organic materials. For the study of materials under external loads (thermal, mechanical, magnetic fields) appropriate sample-environment setups can be installed. The designed experimental arrangement will be compatible to such extensions. Instrumental Characteristics The beamline will consist of an optical hutch and two consecutive experimental stations called NANO1 and NANO2. In the neighboring of the beamline, ANKA-NanoLab for Nano & Micro characterisation will be installed at ANKA as a platform of collaboration in the field of processing and characterisation for Micro and Nano-structured materials (see figure (1)). The heart of the first experimental station NANO1 is a multiple purpose heavy duty diffractometer optimized for in-situ X-ray scattering investigation dedicated to follow the changes of the nano-structured during the growth process as well as for ex-situ experiments. The diffratometer has been designed to be adapted with different types of portable chambers such as Molecular Beam Epitaxy MBE for epitaxial multilayer semiconductor materials, Sputtering and Chemical Vapor Deposition chambers etc… (See fig.2, 3 and 4) The diffractometer will be mounted on a rail to carry out a lateral movement of 1.5 m to the side, to mount a pipe and to guide the X-ray beam to the experimental station NANO2. A detailed design for this second station NANO2 is currently in preparation.
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A concept aiming to operate simultaneously NANO1 and NANO2 in connection with ANKANanoLab for Nano & Micro characterisation will be implemented as follow: As shown in figure (1), a transfer facility for sample environments will be insured from the ANKA-NanoLab to the experimental stations NANO1 and/or NANO2. There will be possibility to mount the sample environment and to perform the necessary alignments without beam at NANO1 while an experiment is running at NANO2. This will lead to efficiency in the use of the beam time for the users. In addition, the users of NANO beamline will benefit from the presence of complementary characterization techniques necessary for surface analysis like Atomic Force Microscopy AFM in vacuum, Scanning Tunnel Microscopy STM available at ANKA-NanoLab This combinatory concept will lead to the improved understanding of the physics and the chemistry of films and leads to expanded applications and new design of devices that incorporates these materials. The NANO beamline offer an energy range from 3 to 25 keV. This covers the K-edges of many common semiconductor materials and of 3d metals, as well as the L-edges of 4f elements and M-edges of 5f-elements, which are crucial for resonant scattering from magnetic systems.
NANO1 NANO2
Optical hutch
ANKA-NanoLab Workshop Control room
Fig. 1: Design of the NANO beamline and its surrounding consisting of ANKANanoLab, workshop and control room
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Hor_Reflecting Mirror #1
Upstream Reflecting Mirror #2
Double multilayer monochromator
Double crystal monochromator
Downstream Reflecting Mirror #3 Hor_Reflecting Mirror #4
Fig. 2: Design of NANO beamline optics and the multipurpose diffractomter of the experimental station NANO1.
o
Description of the beamline optics:
The beamline optics should be able to deliver monochromatic, pink and white beam. It consists of two pairs of mirrors; each pair is acting either on the horizontal or the vertical direction of the beam. By choosing the appropriate radius of curvature for the different mirrors, the beam has to be either collimated or focused at the sample. In addition, four slits are included to protect the mirrors from overfilling. A set of double crystal monochromator with fixed exit (Si111 & Si133) and two pairs of multilayer monochromator (Mo/B4C, bi-layer number N=500) and (Ni/B4C, bi-layer number N=150 will enable us to cover an energy resolution from ∆E/E=10-4, 10-3 up to 10-2 respectively. o Beam features @ the sample
The characteristics of the beam at the sample have been calculated using the ray tracing program XTrace code [1]. The parameters of superconduting undulator are the following: Deflection parameter K = 2, period length λu = 14 mm. gap = 5 mm, Period Number N = 100. - In the monochromatic mode:
In the focused mode Size (HxV)(FWHM) = (171µm x 39 µm). Divergence (HxV)(FWHM) = 0.315 x 0.2 mrad Flux = 2.76 * 1012 [ph/s/100 mA/0.1 %BW]
In the monochromatic collimated mode Size (HxV)(FWHM) = (2 mm x 2 mm). Divergence (HxV)(FWHM) = 0.05 x 0.004 mrad Flux = 6.66* 1012 [ph/s/100 mA/0.1 %BW]
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- In the pink mode:
Multilayer type Multilayer with standard resolution ∆E/E=10-2 Ni/B4C, bi-layer number N = 150, dspacing=3.05 nm, silicon substrate. Multilayer with high resolution ∆E/E=10-3 Mo/B4C, bi-layer number N = 500, dspacing=1.5 nm, silicon substrate Flux at the sample at 8 keV in the focused mode [Ph/s/100mA] Flux [Ph/s/100 mA] = 8.36* 1013 ph/s Flux [Ph/s/100 mA] = 9*1012 ph/s
- In the white mode: NANO beamline will be operational in white mode suited for application like Laue Diffraction. The flux at the sample in the focused mode is 7.21015 ph/s. o Multipurpose diffractomter at NANO1
The diffractometer includes two two different configurations. The first configuration is characterized by a robust tower which should be able to move precisely a chamber of 500 kg without any drawbacks on the set-up (fig.3) while in the second configuration; the tower is replaced by an Euler cradle holding a stage for an environmental chamber with a weight up to 25 kg (fig.4).
References
[1]: Sondes Trabelsi Bauer, Martin Bauer, Ralph Steininger and Tilo Baumbach, Simulation of X-ray beamlines with the new ray tracing tool XTrace , published in Nuclear Inst. and Methods in Physics Research, A 2007, doi:10.1016/j.nima.2007.08.068 . [2]: W. Matz, N. Schell, and W. Neumann, Rev. Sci. Instrum, 72(8), 3344, 2001.
Fig. 3: First configuration of the diffractometer - Used for horizontal geometry - suited for grazing incidence angle µ=[-5°–5 °] - It is suited for heavy environmental chamber up 500 kg - The size of the platform of the holder will be larger than 250 mm x 250 mm Smallest possible mechanical step (µm, ωm) & (δm, γm).
γ1
ω γ2 µ δ1 δ2
Sample movement: (µ, ω):
µm= (0.0002° ± µ∆ < 0.0001°) ωm= (0.00005° ± ω∆ < 0.0001°)
Detector movement: (δ, γ)
δm= (0.00025° ± δ∆ < 0.0002°) γm= (0.00025° ± γ∆ < 0.0002°)
Chamber: sputtering chamber (courtesy Schell et al [2]
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Fig. 4: second configuration of the diffractometer Used for horizontal and vertical geometries Large angular of incidence range θ=[0° – 50 °] - it is suited for baby chamber up to 25 kg - It is suited for baby chamber with a size up to 36 cmx36x40 cm Smallest possible mechanical step: (θm,ωm) & (δm, γm). - Sample movement: (θ, ω)
γ1
γ2
ω δ1 δ2
θm = (0.0001° ± ∆θ < 0.0001°) ωm = (0.00005° ± ∆ω < 0.0001°)
- Detector movement: (δ, γ)
δm= (0.00025° ± δ∆ < 0.0002°) γm= (0.00025° ± γ∆ < 0.0002°)
Contact
Dr. Sondes Bauer Dr. Thorsten Schwarz Beamline scientists Sondes.Bauer@iss.fzk.de Thorsten.Schwarz@iss.fzk.de +49 (0)7247 82-6489 +49 (0) 7247 82-8664
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5.2.4
MPI-MF Beamline
A dedicated beamline for the in-situ investigation of interfaces and thin films is run by the Max Planck Institut für Metallforschung (MPI-MF, Stuttgart) at ANKA as a general scientific facility open for members of the institute and collaborating scientists. Dedication, scientific applications The beamline is dedicated to the structural in-situ characterization of materials in reduced dimensions, like surfaces, interfaces, thin films, and nano-crystalline compound materials, because in the future there is an increased need to study such systems under industrially and environmentally relevant conditions, like high temperature / pressure, external mechanical forces, aggressive gas atmospheres or high electric or magnetic fields [1]. The main research activities carried out at the beamline are strongly connected to the research projects at the MPI-MF. Main topics are: 1) In-situ oxidation experiments of nano materials [2]. 2) In-situ growth studies of organic films 3) in-situ stress measurements in nano metal films. A new synchrotron-based technique was developed for tensile testing of ultrathin polycrystalline and single-crystalline films [3] 4) Structural investigation of polar oxide surfaces and metal / oxide interfaces 5) magnetic properties of bulk alloys and ultra-thin alloys films. The X-ray magnetic circular dichroic (XMCD) effect is exploited in the hard x-ray regime to determine spin- and orbital momentum of the (induced) magnetic moment. Available methods / obtainable parameters, physical properties Types of experiments that can be performed, are: • • • • • • Crystal Truncation Rod measurements to study the atomic structure of surfaces and buried interfaces Experiments under grazing incidence to obtain nm scale depth resolved structural and chemical information Specular and off-specular reflectivity measurements providing the sample electron density profile normal to the surface and the surface and interface roughness profiles Fluorescence measurements to characterize the sample chemical composition In-situ diffraction experiments at high temperatures and under gas atmospheres using heavy sample environments Time resolved experiments to study growth kinetics and interface evolution under controlled conditions.
Instrumental characteristics The beamline can either be operated in monochromatic, pink or white beam mode. The key parameters of the beamline are summarized in the table at the end of this section. Figure 1 shows a drawing of the beamline optics. The main optical elements are a Rh coated Si mirror and the double crystal monochromator (DCM). The DCM consists of a flat Si(111) single crystal and a sagital Si(111) crystal bender for horizontal focusing. The mirror allows to cut the energy spectrum of the incident photons at its higher end to suppress the harmonic content in the monochromatic beam. In addition it is used to focus the beam in the vertical direction.
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Beam position Slits monitor
Rh mirror
Monochromator
Shutter
Slits Phosphorous screen
Beam optics
Figure 1: Schematic Layout of the MPI-MF beamline
Two pairs of horizontal and vertical slits allow to pre-select the beam size on the sample. The heart of the experimental end station is a 2+3 diffractometer that can be operated either in horizontal or vertical sample normal mode (Figure 2). The sample stage has 4 degrees of freedom in the vertical configuration and 5 degrees of freedom in the horizontal configuration. The vertical axis sample rotation stage can support a weight up to 300 kg. The detector arm has in addition two degrees of freedom combined with the possibility of slit rotation on top of the detector arm. All rotations provide an agular resolution of 0.0002°. The detector arm itself is designed to support two detectors simultaneously. The whole instrument is aligned in the incident X-ray beam using a jackable table (colored blue in Figure 2). Two motorized horizontal and vertical slits are mounted on the detector arm. In front of the instrument another pair of slits is defining the incident beam size. Behind the incident slits an ionization chamber is installed to monitor the incident photon flux. Figure 3 shows an in-situ oxidation chamber, as it is mounted on the diffractometer; the growth of oxide islands can be monitored in situ by a 2D and a point detector simultaneously. In the experimental hutch a crane is installed that is used to handle heavier sample environments. A full chi / phi circle can be mounted to run the instrument as a vertical four circle diffractometer.
Energy range Energy resolution (DE/E) Source Flux at sample position Optics 6 keV - 20 keV 3 10-4 @ 9 keV 1.5 T Bending magnet (EC = 6 keV), 0.3 mrad horizontal, 0.03 mrad vertical 10+12 ph/s/0.1%bw @ 9 keV • • Beam size at sample Sample / environment double crystal monochromator with a pair set of Si(111) crystals, second crystal allows horizontal focusing of the beam Rh coated mirror, vertical focusing possible
Typical 1mm (Hor) x 1 mm (Ver)
sample UHV/HP chamber, HT oven, cryostat Multiple circle diffractometer, horizontal / vertical sample normal geometry, horizontal / vertical four circle geometry / • • • • • NaI scintillation counter, 1D wired detector, 2D wired detector, high resolution CCD camera, Si energy dispersive detector analyzer setup for detector arm.
Experimental setup / sample positioning Experimental detectors setup
Software: Control system / SPEC, software for reflectivity and crystal truncation rod analysis Data treatment / evaluation
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Figure2: 2+3 diffractometer in the experimental hutch. The experimental stage can take up heavy duty sample environments for in situ experiments.
Figure 3. In-situ oxidation chamber mounted on the diffractometer; a simultaneous detection using a 2D and a point detector is possible.
Upgrading of the beamline Several upgrades for the beamline have been performed, concerning its performance and the flux available at the sample position. 1) Software upgrade: the old RST system was removed and all beamline components can be controlled via SPEC. The more reliable alignment resulted in a increase of the photon flux at the sample by a factor of two, without any change on the hardware. 2) A 2. fluorescent screen was installed on the beamline: in order to do a fast alignment of the beamline, it is necessary to be able to monitor the beam position after the mirror. 3) a beam polarization monitor was installed in the white beam after the first pair of slits and commissioned. It is needed to guarantee fully linear polarization of the incident beam, which is essential for the XMCD experiments and diffraction experiments. Planned upgrades: Integration of a double detector avalanche photo diode system Installation of linear and 2D pixel detectors References: [1] A. Stierle, et al., Rev. Sci. Inst. 75, 5302 (2004). [2] www.nano2.net [3] J. Böhm, et al., Rev. Sci. Inst. 75, 1110 (2004). Contact
Andreas Stierle Ralf Weigel Beamline stierle@dxray.mpi-stuttgart.mpg.de ralf.weigel@iss.fzk.de weigel@mf.mpg.de 49 (0)711 689-1842 49 (0)7247 82-6597 49 (0)7247 82-6728
Max-Planck-Institut für Metallforschung, Heisenbergstr. 3, D-70569 Stuttgart, Germany
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5.2.5
TOPO-TOMO – X-ray Topography & Tomography Beamline
The TOPO-TOMO beamline currently hosts an experimental station for topography and a new instrument for microradiography and microtomography. The beamline was formerly known as FLUO-TOPO. After relocation of the FLUO-station it is now dedicated to X-ray topography and X-ray imaging. Dedication, Scientific Applications The TOPO-TOMO beamline has been designed and constructed with the support of the Crystallographic Institute of the University of Freiburg for optimal conditions for white-beam Laue topography. A large distance of 30 m between the X-ray source and the sample position as well as the possibility to reduce the effective source size by a pair of slits near the source ensure good transverse coherence, i.e., high angular resolution. In order to avoid artifacts due to unwanted phase contrast from optical elements, the beamline has only a single vacuum window, made of highly polished, high-quality beryllium, and placed close to the experiment. The high degree of spatial beam coherence (up to 300 µm transverse coherence length) makes the beamline suitable for X-ray phase imaging as well. X-ray topography provides a detailed map of the distribution/structure of lattice defects in crystalline samples (dislocations, micropipes, stacking faults), for example in new materials or microelectronic components. Laue X-ray topography provides: o large area sample mapping giving a full image of strain/defect topography of the sample (short range strain: dislocations, long range strain: stress from processing etc.) cross-sectional slice images through the sample (in a manner analogous to TEM) 3D directionality of crystal defects fine lateral resolution (<1 µm) over large areas (at least an order of magnitude greater than areas covered by other techniques).
o o o
Defects or strains in the crystal structure of electronic devices often lead to failure, especially at high integration density and strong internal electric fields. Therefore synchrotron X-ray topography is, e.g., applied to ascertain the electrical impact of intrinsic and extrinsic defect/dislocation distributions, particularly in high field device topologies. Even strain fields from various process steps can be imaged. The Topography beamline allows rapid throughput of samples representing various stages of materials processing or loop-cuts from a device development process. The automated nature of beam conditioning, coupled with automated sample positioning and rapid SXRT geometric re-alignment capabilities is unique and facilitates this type of study. Synchrotron microtomography and microradiography allows, in a non-destructive manner, to image the internal structure of an object. Microtomography using synchrotron light sources delivers 3D images of the object with high resolutions down to the submicrometer range, an excellent signal-to-noise ratio and additional contrast modes like phase contrast and holotomography. Typical applications for microtomography and microradiography are
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o o o o o
detection of voids and pores in industrial components imaging tissue and other soft materials in biological and life science pore formation in metal foams, evolution of particle coarsening in materials science crack propagation characterization of fibre structures, porous media, particle agglomerations by microtomography and a subsequent 3D image analysis diffusion processes in woven materials
o
Available Methods, Obtainable Parameters White Beam X-Ray Topography Detailed information on defect distributions in crystals can be provided by synchrotron X-ray topography in which an intense, highly collimated beam of X-rays is directed at a crystalline sample in Laue or Bragg configuration. This rapid non contact, non destructive analysis technique is mainly used for the study of dislocations, planar defects, stacking faults, growth defects or large precipitates. Also very small local defects like nm-scale voids in Si can be imaged as well as long range strain in electronic devices. High resolution synchrotron microtomography and radiography Microradiography and –tomography are well-established methods for non-destructive evaluation and materials research. The use of synchrotron radiation instead of laboratory sources for tomography and radiography allows to extend the resolution to the submicrometer scale, to reduce noise, beam hardening and cone-beam artifacts as well as to increasing the contrast by the use of monochromatic radiation. This is due to the nearly parallel beam propagation and intense flux of synchrotron light sources. Additionally synchrotron light has a partial spatial coherence which allows one to use interference effects in order to increase the contrast, e.g. phase contrast and holo-tomography. High-resolution and phase contrast radiography are used to investigate micro-structured, multi-component material systems, e.g. to detect delaminations between substrates and glob tops encapsulating wire-bonded devices. Radiographs taken from different projection angles for computed microtomography allow to image objects in three dimensions with a spatial resolution down to the sub-micrometer range, e.g. bio-ceramics in regenerating bone tissue. The subsequent application of 3D image analysis methods derived from stochastic geometry can be used for the determination of size distributions, orientations or spatial correlations within the tomographic, multi-constituent volume images Instrumental Characteristics Good coherence conditions and low background is realized by aperture slits in the front end, 30m source distance and a polished Be-window close to the experiment as the only X-ray optical element in the beamline. The 4-axes sample holder and the vacuum slit system are motorized and SXRT geometries can be changed rapidly from section to large area projection topography in back reflection or transmission mode. A set of in-vacuum filters on two independent sliders can be used to change the spectral distribution of the white beam and attenuate the beam.
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Topo Experiment
From2008 alternatively
Storage Ring
DMM Detector CCD Slits Sample Bending Magnet Be-window Attenuator Slits
XRy Film
Fig. 1: Schematic layout of the TOPO-TOMO beamline. Table 1: Key parameters of the beamline. Energy range Energy resolution [∆E/E] Source Source size Distance source – sample Optics 6 keV - 40 keV (at the position of the sample) White light (optional 1% bandwidth, from end of 2008) 1.5 T Bending magnet (EC = 6 keV), 2 mrad Horizontal, 0.5 mrad Vertical 800µm x 200µm (FWHM, H x V), can be reduced to 5µm x 5µm with slits 30 m • • • Flux at sample position Beam size at sample Experimental setup / sample environment Experimental setup / detectors Primary slits (in the front end, 6 m from the source), Secondary slits (29 m from the source) Be window, 0.5 mm thick, polished (29.5 m from source)
~1x1016 ph/s (10mm x 10mm) up to 13 mm (hor.) x 5 mm (vert.) (radiography/tomography and largearea topography), 10 mm x 0.015mm (section topography) Inert gas, air Photographic films (sub-µm resolution, field of view: approx. 15 x 20 cm2), Scintillator, coupled via microscope optics to a CCD (high dynamic range, PCO4000, 9 µm pixel size, FReLoN 2k14bit, 14 µm pixel size) or CMOS (fast imaging, Photron SA-1, 20 µm pixel size), two optics available: macroscope (1.4x, 3.6x) and microscope (3x, 5x, 10x, 25x, 50x), typical working parameters • • • 25 x 17 mm2 field of view at a pixel size of 6.4 µm 10 x 7 mm2 field of view at a pixel size of 2.5 µm 1.4 x 0.9 mm2 field of view at a pixel size of 0.35 µm
Software / data treatment / evaluation
Instrument control: SPEC / PCO CamWare / TACO camera server Topography data analysis: Orient-Express Tomography data visualization: VG Studio Max, Amira, AVS Express Image processing: IDL, MatLab, Octave Image analysis: MAVI, ImageJ Tomographic reconstruction: PyHST, Octopus
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Figure 2: The topography experiment: (1) Cooled Be-Window, (2) Fast shutter, (3) Sample on two -circle-goniometer and x-/z-translation up to 300 mm (4) Film camera for transmission geometry (5) Digital camera system for transmission geometry on x-/ztranslation
Figure 3: Large area transmission topography of highly doped InP taken with the digital camera, exposure time 60 minutes, distance crystal – film 56 cm: By image post processing of the same original TIFF-file, the topographs are magnified and opimised with respect to high dynamic range or for high sharpness. Visible are straight 60- dislocations with Burgers-vector b = 1/2a [110]. Curved dislocations can be resolved up to a dislocation density of 105-106 cm-2. Dopant inhomogeneities (striations) produce long range strain of several milimeters. (By courtesy of A. Danilewsky, Uni-Freiburg).
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Figure 4: 3D rendering of a tomographic image showing a mosquito (with kind permission by IAEA Vienna): white beam phase contrast with an approx. 5 µm resolution (2.5 µm pixel size).
Upgrades For time-resolved measurements or large-area scans the X-ray film detector is supplemented by a high-resolution X-ray camera based on a thin scintillator coupled to an optical CCD with a motorized positioning system. A double-multilayer monochromator for radiography and tomography has been specified and is now in the construction process. The aimed date for installation is the shutdown period by the end of 2008. The multilayer will provide a monochromatic beam with a bandwidth of approx. 1% over an energy range from 6 keV to 40 keV (peak flux 1011 Ph/s/mm2 @ 200 mA ring current, between 10 and 20 keV). In order to enhance the variability of the beamline, the installation of a retractable highresolution double-crystal monochromator is planned. This enables projection (Lang) topography and rocking-curve imaging. From october 2007 to january 2008 the beamline will be closed for a complete exchange of the vacuum system and the control system.
Contact
Dr. Marian Cholewa Dr. Alexander Rack TOPO-TOMO beamline marian.cholewa@iss.fzk.de alexander.rack@iss.fzk.de +49 (0)7247 82 8655 +49 (0)7247 82 6488 +49 (0)7247 82 6649
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5.2.6
IMAGE – X-ray Imaging Beamline (planned)
IMAGE as a beamline dedicated to imaging techniques, foreseen to be installed at an insertion-device source. The main focus lies on imaging of the direct (forward-scattered) beam, i.e. radiography and tomographic imaging, both in absorption mode and in phasecontrast mode. Tomographic imaging is provided by the established technique of computed tomography and by computed laminography adapted to the investigation of flat, laterally extended objects. Due to a small source size at a modified low-beta section of the storage ring, a high lateral beam coherence allows to exploit phase contrast. Dedication, Scientific Applications X-ray imaging allows the non-destructive investigation of the sample volume in a wide field of applications. The traditional absorption and diffraction imaging techniques are complemented by edge-enhanced and phase-sensitive measurements. Dedicated sample environment systems will allow to follow processes under external load such as temperature (furnaces, cryostats), mechanical load (tensile or compression rigs, fatigue cycling machines) or hydrodynamical pressure (in situ streaming device). On-line reconstruction of 3D images will permit the immediate assessment of the experiment. Standardized 3D processing, visualisation and analysis software will allow an easy interpretation of the results already during the experiment. The spatial distribution of crystal lattice properties will be investigated by direct projection, full-field microdiffraction imaging. In combination with tomographic reconstruction, this will allow a genuinely five-dimensional characterization of samples simultaneously in real and reciprocal space. Available Methods, Obtainable Parameters A variety of complementary techniques will be implemented: o Fast radiography with monochromatic and white beam. Projected 2D attenuation coefficient distribution. Phase-contrast and holotomographic imaging: imaging of low-Z and weakly contrasted materials. Projected refractive index distribution. Parallel-beam tomography and laminography for 3D imaging of objects. 3D distribution of linear attenuation coefficient or refractive index. Full-field microscopy for imaging on the sub-µm or nm scale. Element-specific imaging at absorption edges: distribution of specific elements. Pencil-beam imaging by X-ray focussing devices for the combination of absorption, fluorescence and Compton tomography: distribution of trace elements. Full field X-ray microdiffraction (X-ray rocking curve imaging) with highest spatial resolution on or below the 1 µm scale; analysis and quantification of spatial distributions of crystal lattice misorientations, of defects densities and of local lattice quality in crystalline specimens.
o
o
o o o
o
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Instrumental Characteristics The angular source size (as seen from a given sample point) is of utter importance both for geometric blurring as well as concerning the coherence of the incident X-ray wavefield. Therefore, it is of crucial importance to have a small X-ray source, which should be provided by a low-β section of the storage ring. The instrumentation will be flexible to allow both full-field imaging with a 2D detector system as well as pencil-beam scanning with an energy-dispersive point detector. The latter is of particular interest for combining absorption, fluorescence and Compton tomography. A pencil beam is provided by focussing optics (e.g. compound refractive lenses, Fresnel lenses or Kirkpatrick-Baez mirror/multilayer systems). As 2D detectors, CCD-based detector systems with different, interchangeable optics systems (to provide different spatial resolutions / pixel sizes) will be used. CMOS and frame-transfer CCDs suited for fast realtime imaging at the new beamline are already under extensive commissioning at ANKA today. The FReLoN 2K14 CCD detector, already in use at ANKA, offers a unique combination of fast readout and high dynamic range with ideally matches the requirements of both real-time and slower, high-sensitivity studies. With focussing/magnifying X-ray optics new detector concepts could be applied to improve measurement speed: hybride pixel arrays, for example based on GaAs or CdTe sensor layers, have high quantum efficiency and allow energy discrimination in white-beam mode. A double-multilayer monochromator will provide a selectable energy from a range between 7 and 40 keV. An additional double-crystal monochromator will be used to obtain a reduced energy window and to access higher X-ray energies up to 65 keV (compatible with superconducting undulator/wiggler). To attain spatial resolutions on the sub-µm scale an ultra-precise sample manipulator with small sample run-out during a scan is required. Laminography needs an adjustable tomographic rotation axis for imaging of flat, laterally extended objects. An automatic sample changer system allows one to prepare a series of samples which can be scanned unattendedly, maximising sample through-put. Since phase-contrast imaging is a major point of interest, the beamline optical devices and windows are subjected to stringent requirements concerning surface properties (e.g. flatness) and bulk properties (e.g. lack of inclusions and residual porosity). A polished beryllium or amorphous carbon window close to the experiment is the only disturbing element in the beamline (differentially pumped vacuum tube). The coherence conditions can be improved by aperture slits in the front end.
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Table 1: Key parameters of the beamline. Energy range Energy resolution [∆E/E] Source Source size Coherence length Optics Flux at sample position Beam size at sample Experimental setup / sample environment Experimental setup / detectors Software / Data treatment / Evaluation 7 keV - 65 keV Choice of white light, 10-2, and 10-4 3T superconducting wiggler (EC ≈ 10 keV) 700µm x 70µm FWHM, can be reduced down to 5µm x 5µm by slits 2 µm x 17 µm lateral Aperture slits, polished Be or amorphous carbon window ~ 1012 ph/s/0.1%BW (1mm x 1mm pinhole) Typ: 10 mm (Hor) x 4 mm (Ver) Traction/fatigue stages, cryostat, furnace, streaming device Scintillator detector; CCD-based 2D detector, resolution 1 µm bis 20 µm SPEC, MAVI (Modular Algorithms for Image Analysis), Volume Graphics VGStudioMax, PyHST, ITK/VTK, IDL, MatLab
Storage Ring Experiment 2 Diffraction Imaging Areadetector (CCD) Experiment 1 Tomography
Exchangeable double crystal/ double multilayer monochromator
S lits Ionization Cham ber Areadetector (CCD)
Sam ple Attenuator
S Insertion Device c.
Sample 6-circle diffractometer Gonio meter System
Fig. 1: Schematic layout of the planned IMAGE beamline.
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Figure 2: Recent advances in X-ray micro-tomography provide the biologist with an opportunity to view 3d volume images of even tiny organisms with a resolution on the µm scale. Internal structures, in their natural state, can thus be studied without resorting to dissection or histology. The figure shows the external and internal structure of an insect head (Gyrophaena sp.) obtained at the ANKA. The 3d rendition of a reconstructed 3d data set was obtained by phase-contrast microtomography. Length of insect head: approx. 0.5 mm. Voxel size 1µ m.
Contact
Tilo Baumbach Lukas Helfen Alexander Rack Dr. Marian Cholewa Beamline tilo.baumbach@iss.fzk.de helfen@esrf.fr alexander-oliver.rack@iss.fzk.de marian.cholewa@iss.fzk.de +49 (0)7247 82-6820 +33 4 76 88-2558 +49 (0)7247 82-6488 +49 (0)7247 82 8655 -
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5.3 Micro-Fabrication
LIGA I, II, III X-ray Lithography Beamlines
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5.3.1
LIGA I, II, III - X-ray Lithography Beamlines
The microstructure laboratory at ANKA consists of three beamlines for deep X-ray lithography, each dedicated to a specific task in the LIGA-process, which are high resolution X-ray mask making (LIGA I), deep X-ray lithography (LIGA II) and ultra deep X-ray lithography (LIGA III). The whole laboratory is placed inside a clean room for accurate environment conditions. The experimental equipment, together with the microstructure fabrication capabilities at IMT/Karlsruhe Research Center, is a unique installation for high precision and high aspect ratio microstructure fabrication.
Dedication, scientific applications In deep X-ray lithography an X-ray mask is copied into an X-ray sensitive resist by synchrotron radiation via shadow printing. The resist thicknesses range from 20 µm up to several millimeters thick layers. X-rays from a synchrotron radiation source are used primarily to penetrate those thick layers, while keeping the top to bottom dose-ratio in a specific range, and due to their high parallelism allowing the fabrication of very high vertical microstructures with a side wall roughness in the optical range ( ≤ 20 nm). The X-ray mask consists of an X-ray transparent membrane, such as a 2.5 µm thick titanium membrane or a 500 µm thick beryllium sheet, and gold absorber structures to stop incoming X-rays. The contrast of the mask and therefore the thickness of the gold absorbers has to be sufficient to reduce the top dose in the resist below the minimal developing dose underneath the gold absorber structures and to reduce the dose from secondary electrons produced at the boundary layer in the substrate, by X-rays penetrating the gold absorber structures and absorbed in the metallic substrate. Otherwise sidewall attacks by the chemical developer and insufficient adhesion of freestanding resist structures occur. The combination of e-beam writing and X-ray mask making with synchrotron radiation allows the fabrication of structure details as small as 200 nm in 200 µm resist layers. Those structure details are not achievable by any other X-ray mask making method (e.g. laser writing and UV-lithography).
Available Methods / Obtainable Parameters Aligned exposures for pre-structured substrates are available and used on a routine basis. Moveable micro structures are fabricated using the sacrificial layer technique, where a prestructured titanium interface on the substrate is selectively etched against the metallic microstructure. Structures with different level heights are processed by using micro milled and drilled substrates (Figures 1). At LIGA I and II an external alignment system is available, while an internal alignment system is installed at LIGA III. In both cases, the pre-structured substrates are aligned relative to the X-ray mask via a microscope and pattern recognition hard- and software for fast and accurate alignment. An instrumental accuracy of 0.5 µm has been measured.
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Figure 1: Examples of deep X-ray lithography structures fabricated at ANKA.
(a) High resolution X-ray mask fabricated at LIGA I, smallest structure detail 200 nm.
(b) Crossed X-ray lens structures fabricated at LIGA II, height 500 µm.
(c) 200 µm thick nickel gear beneath a 1600 µm UDXRL resist structure, fabricated at LIGA III.
Instrumental characteristics Three beamlines are installed and equipped with state-of-the-art X-ray scanners, fabricated by the company JenOptik in collaboration with IMT/Karlsruhe Research Center. Each beamline is dedicated to a specific task: high resolution X-ray mask fabrication, deep X-ray lithography and ultra deep X-ray lithography. The white spectrum from ANKA dipole magnets are used and tailored to the energy range of interest using grazing incidence mirrors as low energy pass-filters and low-Z filter foils, mounted in a filter chamber, as high energy passfilters (Fig. 2).
Figure 2: Available spectral distributions at different X-ray lithography beamlines at the mask plane. While the beamline LIGA III uses the white synchrotron radiation spectrum of a dipole magnet, LIGA I and LIGA II are using grazing incidence mirrors as low energy pass filter. Due to the high energy cut-off, X-ray masks with thinner gold absorbers and therefore higher accuracy can be used, leading to very precise microstructure products.
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Figure 3a: Beamlines LIGA I and II use grazing incidence mirrors; a chromium-coated silicon mirror for sub-µm lithography and mask making (LIGA I) and a nickel-coated silicon mirror for standard deep X-ray lithography (LIGA II)
Figure 3b: Schematic layout of the LIGA III beamline. LIGA III uses the white synchrotron radiation from a dipole magnet. It is used for ultra deep X-ray lithography.
Table 1: Current key parameters (real-time updates: see webpage). LIGA I Energy range Source Optics 2.2 keV - 3,3 keV LIGA II 2.5 keV – 7.0 keV LIGA III 2.5 keV - 15.0 keV 1.5 T bending magnet, bending radius: 5.559 m Be-window thickness: 225 µm in total optional low-z filters and band-pass filters: C, Al, Ti, V, Fe, Ni, Cu
1.5 T bending magnet, 1.5 T bending magnet, bending radius: 5.559 m bending radius: 5.559 m Be-window thickness: 175 µm in total gracing incidence mirror: Si/200nm Cr @ 15.4 mrad optional low-z filters: C, Al 14.84 m 8.61 m Be-window thickness: 225 µm in total gracing incidence mirror: Si/200nm Ni @ 8.65 mrad optional low-z filters and band-pass filters: C, Al, Ti, V, Fe, Ni, Cu 14.73 m 9.20 m
Distance: source point -mask plane Distance: source point -mirror
16.37 m
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Be-window aperture Usable horizontal fan : Sample / sample environment Experimental setup
20 mm (vertical) * 110 mm (horizontal) 108 mm 100 mbar He JenOptik DexKfK X-ray scanner with tilting option (+/- 60°) External, 2 µm
20 mm (vertical) * 110 mm (horizontal) 108 mm 100 mbar He JenOptik DexKfK X-ray scanner with tilting option (+/- 60°) External, 2 µm
20 mm (vertical) * 110 mm (horizontal) 108 mm 100 mbar He JenOptik Dex02 X-ray scanner with tilting option (+/- 60°) and rotation option (362°) Internal, 0.2 µm
Alignment / instrumental overlay accuracy Software
Dex control software with interface to beamline control software
Dex control software with interface to beamline control software
Dex control software with interface to beamline control software
A homogeneous synchrotron radiation fan of 108 mm width is available at all scanner locations. Exposures are performed under a 100 mbar He atmosphere. The high precision Xray scanners move the mask/resist-package with a speed of up to 50 mm/sec vertically through the synchrotron radiation beam to achieve a homogenous exposure field across the microstructure design window on the X-ray mask. An additional tilting device mounted on top of the vertical stage allows the fabrication of inclined microstructures. A tilting of up to 60° with accuracy of 0.05° is available. The combinations of inclined and vertical microstructures are realized by multiple irradiation inserting mechanically fabricated apertures in front of the X-ray mask. These apertures are adapted to the design of the microstructures and allow the irradiation of special areas of the X-ray mask. A repeatable overlay accuracy of apertures and X-ray masks of 30 µm have been measured. Upgrading of the beamlines In 2007/8 a new scanner with an automatic handling system will be installed at LIGA III. LIGA III will be used for commercial manufacturing of microstructures.
Beamline Scientists / Contact Persons
Franz Josef Pantenburg Martin Boerner Beamline pantenburg@imt.fzk.de martin.boerner@imt.fzk.de +49 (0)7247-82 2600 +49 (0)7247-82 4437 +49 (0)7247-82 6855
Forschungszentrum Karlsruhe, Institut fuer Mikrostrukturtechnik, P.O. Box 3640, D-76021 Karlsruhe, Germany
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Legend for the schematic beamline layouts presented in the beamline description
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6 ANKA User Services
User services make available the capabilities of ANKA and the corresponding ISS expertise to a large regional, national and international scientific community. The Karlsruhe Research Center runs ANKA as an attractive, highly efficient user facility and employs the broad, multidisciplinary expertise of different institutes of the Karlsruhe Research Center to support the needs and demands of the external users. ANKA offers optimum conditions for industrial use of synchrotron radiation by rapid access schemes and by professional industry oriented project management. Methods development, projects with inherent scientific risk and longterm research projects for systematic studies can be conducted. The various modes of access for users and customers to ANKA illustrated (Figure 4-1) and described below.
Figure 1: Graphical representation of the five access routes to beamtime at ANKA, via Calls for Proposals, European networks, Karlsruhe Research Center in-house research in the HGF programs, custommers for commercial services and through the collaborative research groups (CRGs).
Calls for Proposals are published every 6 months in scientific journals and distributed widely to universities, research centers and scientific associations. Beamtime is granted to external users free of charge via an independent peer review procedure, on the condition that the results will be published in scientific journals. The proposals are graded according to their scientific excellence and technological relevance. In addition to regular proposals, applicants can apply for long-term projects and for rapid access. Collaborative Research Groups (CRGs) are institutions that operate their own beamlines or experimental stations and allow a certain beamtime fraction to be allocated via peer review. In-house research receives access to ANKA as an essential tool for fulfillment of Karlsruhe Research Center’s R&D mission within the programs of the Helmholtz Society. This mode of access is open to all institutes of the Forschungszentrum and external collaboration partners. European Networks in which ANKA or its participating institutes are involved provide access to ANKA beamtime for other the consortium members.
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Networks include the Integrating Action on Synchrotron and Free Electron Laser Science (IASFS), the Network for Actinide Sciences (ACTINET) and Diagnostic Applications of Synchrotron Infrared Microscopy (DASIM). The Grand European Initiative on Nanoscience and Nanotechnology using Neutron and Synchrotron Sources (GENNESYS) is a European project which aims to bridge the gap between the research needs and future challenges of the nanotechnology community, and the capabilities of neutron and X-ray techniques. Commercial Services are provided to customers by ANKA Commercial Service (ANKACOS). About 125 projects by internal and external users have been received per year since 2003 and were evaluated and graded within a peer review process (Figure 4-2). The relative distribution of beamtime use is given in Figure 4-3.
Figure 2 Beamtime applied for and delivered to users in 2005 - 2007.
500 450 beamtime days/call 400 350 300 250 200 150 100 50 0 5th Call 01.04.05 30.09.05 6th Call 01.10.05 31.03.06 7th Call 01.04.06 30.09.06 8th Call 01.10.06 31.03.07
beamtime requested by users beamtime allocated by ARC
9th Call 01.04.07 30.09.07
Other German research facilities 15%
Foreign countries 13% Industry 5% ISS 13%
Figure 3: Use of beamtime in 2006.
German universities 31%
HGF 3%
FZK 20%
Contact Persons ANKA User Office
Jacqueline Heinrich Rosemarie Kuppinger-Knapp jacqueline.heinrich@iss.fzk.de Kuppinger-knapp@iss.fzk.de +49 (0)7247-82 6188 +49 (0)7247-82 6071
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7 Official Contact, Addresses
For further information please use the addresses below or contact directly the beamline scientists named in the chapters above.
ANKA Angströmquelle Karlsruhe Forschungszentrum Karlsruhe GmbH
Industrial Customers ANKA-COS Scientific Users Institute for Synchrotron Radiation (ISS)
P.O. Box 3640 D-76021 Karlsruhe, Germany or Hermann-von-Helmholtz-Platz 1 D-76344 Eggenstein, Germany Dr.-Ing. Udo Retzlaff Administrative Director +49 (0)7247 82 6066 (phone) +49 (0)7247 82 6287 (fax) E-mail: udo.retzlaff@anka-cos.fzk.de Internet http://www.ANKA-CoS.de
P.O. Box 3640 D-76021 Karlsruhe, Germany or Hermann-von-Helmholtz-Platz 1 D-76344 Eggenstein, Germany
+49 (0)7247 82 6071 / 6288 (phone) +49 (0)7247 82 6789 / 6287 (fax) E-mail: info@iss.fzk.de
http://www.fzk.de/anka/
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