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Compton X-ray Update
Jim Boyce
Jefferson Lab
User/LPC Meeting, January 17-18, 2002
JRB: LPC Jan. 17, 2002 Operated by the Southeastern Universities Research Association for the U.S Department of Energy 1
Outline
• Concept review
• Summary of IRDEMO results
(most data taken in parallel with other Users)
• Future X-ray User Station
JRB: LPC Jan 17, 2002 Operated by the Southeastern Universities Research Association for the U.S Department of Energy Page 2
Jefferson Lab FEL LAYOUT
User Labs (upstairs)
JRB: LPC Jan 17, 2002 Operated by the Southeastern Universities Research Association for the U.S Department of Energy Page 3
IR-electron bunch collision
IR bunch
Electron bunch
First x-rays of collision produced when bunches 1st meet.
A
Last x-rays of collision produced when bunches separate.
A Z
X-rays A through Z travel at c with electron bunch.
A Z Time
s x-rays = selectrons
JRB: LPC Jan 17, 2002 Operated by the Southeastern Universities Research Association for the U.S Department of Energy Page 4
Basic Laboratory Geometry – Side View
PC
Amp MCA
-
X-ray detector
(Cooled Si PIN diode)
X-rays Diffracting
crystal e- beam
Lab angle (2q) 1/g
e- beam Wiggler
IR
IR
Mirror Beam pipe Mirror
a
Insertable thin
Thomson
Al foil (CTR)
Backscatter
y (vertical) Coordinate system
z (electron beam direction in wiggler)
x (horizontal, i.e., parallel to lab floor)
JRB: LPC Jan 17, 2002 Operated by the Southeastern Universities Research Association for the U.S Department of Energy Page 5
CTR electron bunch length measurement
FWHM
sbunch = = 89.2 mm
2.354
sbunch
c = 298 x 10-15 sec
300 fsec
JRB: LPC Jan 17, 2002 Operated by the Southeastern Universities Research Association for the U.S Department of Energy Page 6
Actual Typical spectra
3.48 keV
100
0
4.98 keV
Counts
Net Counts in peak = 32,000.
1000 Signal/Noise = 90 : 1
15 seconds
0
2000
10.1 keV
0
1 7 13
Ex-ray (keV)
JRB: LPC Jan 17, 2002 Operated by the Southeastern Universities Research Association for the U.S Department of Energy Page 7
Measured X-rays
20
15
Ex (keV)
10
3rd harmonic
lasing
5
0
0 1 2 3 4 5 6 7
IR wavelength (microns)
JRB: LPC Jan 17, 2002 Operated by the Southeastern Universities Research Association for the U.S Department of Energy Page 8
Present FEL vs FEL Upgrade (2002)
109 1012
Berkeley Undulator Brightness
1011
Brightness (ph/sec/mm2/nrad2/0.1%BW)
108
Berkeley Undulator Flux
1010
Flux (sec-1, 0.1% BW)
107 Flux JLab Upgrade 0.1% BW
109
Berkeley Bend Brightness
106 108
Flux JLAB, 0.1% BW
Berkeley Bend Flux
107
105
106
Brightness JLab Upgrade
104
105
Brightness JLAB
103 104
0.0 10. 20. 30. 40. 50.
X-ray Energy (keV)
JRB: LPC Jan 17, 2002 Operated by the Southeastern Universities Research Association for the U.S Department of Energy Page 9
Simultaneous production of THz, 3 micron, and 10 keV X-rays
• Picosecond pulses at 37.4 MHz THz pulses, ~2 W total power
• Synchronized to femtosecond
levels
Sample 100
Wavenumber (cm-1)
10 keV X-ray > 105 ph/sec/0.1% BW
3 micron lasing >1 kW
Intensity (a.u.)
Counts
16 32
2.8 0
2.9 3.0
lIR(mm) X-ray energy (keV)
JRB: LPC Jan 17, 2002 Operated by the Southeastern Universities Research Association for the U.S Department of Energy Page 10
FEL Upgrade X-ray Station
X-ray Station
JRB: LPC Jan 17, 2002 Operated by the Southeastern Universities Research Association for the U.S Department of Energy Page 11
Proposed X-ray Station for Users
X-ray Station
10 – 50 keV
6.06 m IR (pump)
Wiggler
Sample
JRB: LPC Jan 17, 2002 Operated by the Southeastern Universities Research Association for the U.S Department of Energy Page 12
Research & Collaborations
Potential Fields of Research
• Solid State Physics/Material Science
-Temporal dynamics of condensed matter phase transitions
- Monitoring structural changes in materials with ultra-fast time resolution
- Heat propagation at sub-micron dimensions
• Biology & Chemistry
- Short-range order changes in chemical reactions
• Fast X-ray detectors
Collaborations
• Solid State Physics/Material Science
-University of Georgia (Prof. Uwe Happek)
• Biology & Chemistry
-East Carolina University (Prof. John Sutherland)
Invitation
• We invite anyone interested in ultra fast phenomena to partner
with Jefferson Lab in the exploration of this new field of science.
JRB: LPC Jan 17, 2002 Operated by the Southeastern Universities Research Association for the U.S Department of Energy Page 13
Summary
Jefferson Lab FEL was high flux source of short pulse X-rays
IRDEMO X-ray source:
• Signal to noise ratio ~ 90:1
• X-rays time correlated with IR
• Tuneable from 3.5 keV to 18 keV
• X-ray bunch length is ~ 300 fsec long
• >1010 X-rays/sec at 75 MHz (2 kW)
Future:
• Incorporating X-ray capabilities into FEL upgrade design
(X-rays 10 to 50 keV)
• IR-X-ray pump-probe station (now in design stage)
JRB: LPC Jan 17, 2002 Operated by the Southeastern Universities Research Association for the U.S Department of Energy Page 14
FEL X-ray Team & Contributors
(alphabetical) • Kevin Jordan
• George Biallas • Geoff Krafft
• Steve Benson • Stan Majewski
• Jim Boyce • Lia Merminga
• Dave Douglas • George Neil
• Fred Dylla • Michelle Shinn
• Phillip Folk (RPI) • Tim Siggins
• Archie Fripp (NASA – ret.) • Richard Walker
• Uwe Happek (U. of GA) • Gwyn Williams
Work supported by the US DOE Contract # DE-AC05-84ER40150,
the Office of Naval Research, Commonwealth of Virginia and
the Laser Processing Consortium.
JRB: LPC Jan 17, 2002 Operated by the Southeastern Universities Research Association for the U.S Department of Energy Page 15
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