Hamburg pipe project � status and plans

Hamburg pipe project – status and plans Benoit Florins, Krzysztof Piotrzkowski, Guido Ryckewaert Université Catholique de Louvain • Introduction: Reminder what the HH pipe is • First technical meeting - CERN, Nov 9 • List of open questions and tests • Next steps Small project: moving pipe was to minimize distance to e-beam during ep collisions – detector readily accessible, in normal atmosphere Forward Workshop, Manchester Dec'05 K.Piotrzkowski - UCLouvain Hamburg pipe  Routinely used at HERA at high L, since 1995 … : Technical coordinator: Uwe Schneekloth (DESY) bellows shielding moving pipe Forward Workshop, Manchester Dec'05 K.Piotrzkowski - UCLouvain Forward Workshop, Manchester Dec'05 K.Piotrzkowski - UCLouvain Forward Workshop, Manchester Dec'05 K.Piotrzkowski - UCLouvain The “Hamburg pipe” was originally proposed for the PETRA wiggler beam line, and is still in use today. A similar solution, suggested by U. Schneekloth (DESY) in 1994, was used for tagging photoproduction at HERA by detection of very forward electrons. Basically, a section of beam pipe is oversize and is displaced sideways with the detectors attached, but separated from the vacuum by an “envelope”. The pipe, some 43 m from the interaction point, was routinely displaced after HERA was in collision mode, such that the (calorimetric) detectors were in the working position up to about 20 mm from the beam. The step motors and control electronics were the same as for the HERA electron collimators. The detector could be easily maintained and was successfully and routinely operated for 6 years providing data for several publications. PETRA wiggler pipe – original inspiration, still in use… Forward Workshop, Manchester Dec'05 K.Piotrzkowski - UCLouvain For an FP420 application some modifications might be necessary, with an RF shield (through which the detectors approach the beam via narrow slots), to minimise any impedance change on the beam. The design of RF screen and contact of the HERA chamber were very simple and cheap. Some copper braid was used. Before the chamber was built, the design had been tested by moving prototype many (several thousand) times. Parking position Working position RF screen? Bellow Detectors a few m apart Forward Workshop, Manchester Dec'05 K.Piotrzkowski - UCLouvain Aims of the meeting of 9 November for FP420. • Identify the relevant open issues requiring R&D, studies and tests, and start to define the set of the 'global' parameters for the design. • Exchange all possible technical info on the materials, parameters, specifications and requirements in each particular domain. • Establish personal contacts and future exchanges, plan next steps and work. See: www.fynu.ucl.ac.be/users/k.piotrzkowski/fp420/ Forward Workshop, Manchester Dec'05 K.Piotrzkowski - UCLouvain Draft Agenda of Informal Discussions • 09.30 Introduction, K.Piotrzkowski & K.Potter Detector layout A second generation cryostat (Sebastien Marque) Integration into the LHC - Help from TS/LEA. (Emmanuel Tsesmelis, Daniela Macina) The 'Hamburg Beampipe' concept, Krzysztof Piotrzkowski Mechanical issues (Tadeusz Kurtyka) Vacuum Issues (Christian Rathjen) • ~10.00 • • ~10.30 • • ~11.00 • Lunch break • 14.00 • • ~15.00 • RF Issues (Elias Metral) Alignment - not to be forgotten (Helene Mainaud) Suitable High precision BPM's (Rhodri Jones) Who does what next? - General discussion K.Piotrzkowski - UCLouvain Forward Workshop, Manchester Dec'05 Connection Cryostat “COLD MASS” • T (vacuum pipes) < 3.3 K to allow sufficient H2 cryopumping => vacuum pipes immersed in a bath of superfluid He • Minimal distance between bus-bars and beam pipes to avoid B magnetic field on the beam Forward Workshop, Manchester Dec'05 K.Piotrzkowski - UCLouvain LHC Integration issues • • Continuity cryostat (S. Marque) • • • • • Assure the continuity of all LHC arc services Volume left for detectors Bellows Thin windows Movement Moveable detectors (~20 mm with respect to beam (BPM’s) 5 micron precision on the detector to beam distance ( ≥ 3 mm) Assymetry ~ 20 mm movement (linearity) Long term stability and calibration Beam impedance RF screens Sliding fingers Isolation valves NEG pumps Bakeout Ion pumps Mechanical issues (Tadeusz Kurtyka, TS/MME) • • Alignment (Helene Mainaud, TS/SU) • • • • • Precision BPM’s (Rhodri Jones, AB/BDI) • Wakefields and RF issues (Francesco Ruggiero, Elias Metral, AB/ABP) • • • • Vacuum issues (Ray Veness, Christian Rathjen, AT/VAC) • • • • • LHC/Experiment interface and general coordination (Emmanuel Tsesmelis, Daniela Macina, TS/LEA) • A detector alignment test bench? K.Piotrzkowski - UCLouvain Forward Workshop, Manchester Dec'05 A horizontally displaceable beam-pipe at the LHC ? A basic schematic FP420 Detector layout Beam two ~8 m ~ 85 mm diameter Beampipe ? Double set of bellows Double set of bellows 20 mm movement 44 mm diameter non-concentric beampipe 20 mm movement K. Potter slide Forward Workshop, Manchester Dec'05 K.Piotrzkowski - UCLouvain A horizontally displaceable beam-pipe at the LHC Alignment Bellows BPM Thin window RF screen, 15° Off-momentum proton D ± 5 μm Detectors BPM Bellows Enlarged pipe ~85 mm diam. 44 mm diameter round pipe thick copper ? Plan view Forward Workshop, Manchester Dec'05 K. Potter slide K.Piotrzkowski - UCLouvain FP420 ISSUES: Louvain perpective DETECTOR Layout and dimensions of the detectors Vacuum window size and thickness How are detectors fixed to support structure INTEGRATION INTO LHC Clearance available vertically and longitudinally in modified cryostat Define overall space available for the device outside the cryostat in the tunnel Longitudinal location of detectors (w.r.t. each other, to ends of movable tube, to BPM's) Height of beam line to ground PUMPS – VACUUM Isolation valves Required vacuum Pumping system: what types of pumps? Bakeout temperature – tube elongation MECHANICAL Recommendations / specifications for materials to be used for different purposes Precision and tolerances on: - beam tube positions (height, laterally – x,y) - detector positions Intermediate beam pipe supports required? End flange design/layout of LHC beam pipe to connect moving pipe Isolation from vibrations required? (Marble table?) Required dimensions/shapes for the different elements: beam pipe, transitions, RF screens, sliding tables – for example, what is the allowed length of the wall at 3 mm from the beam axis from the RF point of view? Use positioning (driving motors, control system, …) and position measurement devices same as elsewhere in LHC? Electric end-switches required? Mechanical stops provided. What interface with LHC control system? What if moving pipe system "crashes" – gets stuck? Emergency exit/withdrawal system ? MISCELLANEOUS Any cooling required? What are the radiation levels in this area? ALIGNMENT General philosophy: - either: the detectors always move to identical positions and beam is moved to canonical position using BPM's - or: beam position is measured and detectors are moved to canonical distance from actual beam axis How will the moving beam pipe device be aligned in the tunnel at installation? What needs to be provided on the support structure? TESTS What type of testing is foreseen during prototyping? Is it useful to test not a full-scale prototype? Use mock-ups? Do we plan specific (integration/alignment) tests at CERN? At test beams? Forward Workshop, Manchester Dec'05 K.Piotrzkowski - UCLouvain INTRODUCTION BEAM BEAM motor RF screen marble table beam moving tube detector axis moving tube marble table G. Ryckewaert slide Mechanical Specifications for materials Required dimensions? Electric end switches? end flange? Interface with LHC control system? intermediate support? use positioning? Detector position (precision-tolerance)? emergency exit system? G. Ryckewaert slide Vacuum and detectors pumping system + required vacuum? isolation valves? detector fixing? layout bakeout T° - tube elongation? detector? G. Ryckewaert slide G. Ryckewaert slide INTEGRATION INTO LHC clearance available in modified cryostat? define overall space? how aligne moving beam pipe? location of detector? any cooling required? radiation levels? height of beam? Forward Workshop, Manchester Dec'05 K.Piotrzkowski - UCLouvain G. Ryckewaert slide D. Dattola / S. Marque FP420 - 09/11/2005 Forward Workshop, Manchester Dec'05 K.Piotrzkowski - UCLouvain D. Dattola / S. Marque FP420 - 09/11/2005 Forward Workshop, Manchester Dec'05 K.Piotrzkowski - UCLouvain Heat exchanger Vacuum Vessel Cold to warm transition HeII warm to cold transition Beam pipes Usable Volume (Tamb) BusBars Support post (Tamb) Support posts (T) Radiation Shielding (beam-gas + proton losses) Bottom tray thermalisation Magnetic shielding (busbars on beam pipes ?) Thermal insulation on cold mass structure S. Marque / D. Dattola FP420 - 09/11/2005 Thermal shield (actively cooled 80K) – 1mm 1.9K Vacuum >= 2mm Vacuum >= 4mm 300K MLI (2x10layers) – 4K/6mm MLI (2x15layers) – 80K/12mm FROM 1.9K to 300K: AT LEAST 25mm S. Marque / D. Dattola FP420 - 09/11/2005 Forward Workshop, Manchester Dec'05 K.Piotrzkowski - UCLouvain One possible solution: Wire Positionning System… • WPS sensors use a capacitive measurement technique along 2 perpendicular axes. They measure the distance between its mechanical axis and a stretched wire which is the reference. On each measurement axis, the wire sits between 2 electrodes WPS does not include any electronic components The wire is made of carbon fibers and its geometry is maintained by a sheath of woven PEEK filaments. Resolution: 0.1 mm Range: 10 mm along two axes Repeatability: 1 mm Bandwidth: 0-100 Hz • • • • H. Mainaud slide Forward Workshop, Manchester Dec'05 K.Piotrzkowski - UCLouvain One exemple: the energy spectrometer • • Energy spectrometer installed in the LEP in 1999 to determine the beam energy with a relative accuracy of 10-4. Which requires an accuracy of 1 mm on the beam position • 12 WPS were installed to determine the relative mounting stability of each BPM, in order to avoid unnoticed movements. H. Mainaud slide Forward Workshop, Manchester Dec'05 K.Piotrzkowski - UCLouvain Performance of the WPS (example of the energy spectrometer) • One basic test to check the behavior of the sensors: to change the set point of the water temperature regulation system for the BPM. The expansion of the BPM determined from the WPS signals can be compared with the expansion coefficient of aluminium from which BPM are made. • Other tests demonstrate a WPS resolution of less than 0.3 mm. H. Mainaud slide Forward Workshop, Manchester Dec'05 K.Piotrzkowski - UCLouvain Alignment system and accuracy To determine the position accuracy, we need to answer all the following questions… Forward Workshop, Manchester Dec'05 K.Piotrzkowski - UCLouvain Some first answers… Integration of the alignment system and its constraints as soon as possible Influence of all these constraints on the chosen alignment system will have to be tested. Forward Workshop, Manchester Dec'05 K.Piotrzkowski - UCLouvain Forward Workshop, Manchester Dec'05 K.Piotrzkowski - UCLouvain Forward Workshop, Manchester Dec'05 K.Piotrzkowski - UCLouvain Forward Workshop, Manchester Dec'05 K.Piotrzkowski - UCLouvain Next steps • Study further two scenarios of the cryostat modification – with detectors in the air, or in the insulation vacuum (Sebastien); • Study RF properties of two scenarios for the pipe shape (Elias, Cockroft, Louvain) • Re-think and possibly re-define the alignment/BPM precision needed, and the procedure to reach it (Keith, Louvain, Mike?) What has been assumed about beam momentum spread, emittance and detector distances in the acceptance and resolution estimates? • Radiation shielding??? (Sebastien) • Louvain plans to build a prototype pipe and test it in spring’06 for the stability, rigidity, etc.; a small prototype of the HPS is planned for the test beam studies with edgeless detectors at CERN in Sep’06 • CERN will work on alignment issues (TS/LEA & SU with a Manchester RA??) • BPM development may be needed (Cockroft & CERN?) Forward Workshop, Manchester Dec'05 K.Piotrzkowski - UCLouvain Lines of attack in Louvain now • Concentrate mostly on the pipe design: Pockets vs Long Indent Need urgently feedback on RF properties of a given design AND definitions of detector volumes AND required alignment precision • In parallel watch & consider implications/ possibilities for integration scenario: Open Access (in ‘air’) vs Limited Access (in isolation vacuum) Need decision on this issue asap – otherwise very difficult to progress in the complete system design Forward Workshop, Manchester Dec'05 K.Piotrzkowski - UCLouvain Pocket design I (B. Florins) Forward Workshop, Manchester Dec'05 K.Piotrzkowski - UCLouvain Pocket design II (B. Florins) Forward Workshop, Manchester Dec'05 K.Piotrzkowski - UCLouvain Indent design I (B. Florins) Forward Workshop, Manchester Dec'05 K.Piotrzkowski - UCLouvain Indent design II (B. Florins) Forward Workshop, Manchester Dec'05 K.Piotrzkowski - UCLouvain Plans: Build a moving pipe prototype in spring/summer (Which length? Both schemes?) to test it in the lab (robustness and precision) and at the beam in summer/fall’06 Arrive to the proposal of the moving pipe integration – is possible to reach that by summer’06? Strong and efficient interactions with the cryostat design are crucial… To reach these goals we need to set up the FP420 working group scheme/work plan starting Jan’06 Welcome on board! Forward Workshop, Manchester Dec'05 K.Piotrzkowski - UCLouvain