ILC Beam Tests in End Station A ILC
ILC Beam Tests in End Station A ILC R&D Meeting, Dec. 18, 2006 M. Woods, SLAC BPM energy spectrometer (T-474/491) Synch Stripe energy spectrometer (T-475) Collimator design, wakefields (T-480) Bunch length diagnostics (w/ LCLS, T-487) IP BPMs/kickers—background studies (T-488) LCLS beam to ESA (T 490) Linac BPM prototypes EMI (electro-magnetic interference) http: //www-project. slac. stanford. edu/ilc/testfac/ESA/esa. html M. Woods, SLAC 1
ILC Beam Tests in End Station A 6 test beam experiments approved: T-474/491, T-475, T-480, T-487, T-488, T-490 2006 Runs: i. January 5 -9 commissioning run ii. April 24 – May 8, Run 1 iii. July 7 -19, Run 2 2007 Runs (dates tentative): i. March 7 -26, Run 3 ii. July 5 -8, T 490 w/ LCLS beam iii. July 9 -22, Run 4 + requesting two 2 -week runs in FY 08 M. Woods, SLAC 2
ILC Beam Tests in End Station A 3 posters/papers presented at EPAC 06: • M. Woods et al. , “Test Beam Studies at SLAC End Station A, for the International Linear Collider, ” SLAC-PUB-11988, EUROTEV-REPORT-2006 -060, EPAC-2006 -MOPLS 067. www-project. slac. stanford. edu/ilc/testfac/ESA/files/EPAC 06/SLAC-PUB-11988. pdf • N. Watson et al. , “Direct Measurement of Geometric and Resistive Wakefields in Tapered Collimators for the International Linear Collider, ” SLAC-PUB-12029, EUROTEV-REPORT-2006 -059, EPAC-2006 -MOPLS 066. www. eurotev. org/e 158/e 1365/e 1378/e 2179/EUROTe. V-Report-2006 -059. pdf • G. Christian et al. , “The Electromagnetic Background Environment for the Interaction-point Beam Feedback System at the International Linear Collider, ” EUROTEV-REPORT-2006 -072, EPAC-2006 -THPCH 08. www. eurotev. org/e 158/e 1365/e 1378/e 2189/EUROTe. V-Report-2006 -072. pdf 9 abstracts submitted to PAC 07 • T-474 (2), T-480 (3), T-488 (2), T-Bunchlength (1), T-EMI (1) Status Report on ILC-ESA Test Beam Program to SLAC EPAC Dec. 5 http: //www. slac. stanford. edu/grp/rd/epac/Meeting/200612/index. html M. Woods, SLAC 3
ESA Equipment Layout Wakefield box Wire Scanners blue=FY 06 red=new in FY 07 rf BPMs FONT-T 488 18 feet Ceramic gap BLMs T-487: long. bunch profile Upstream (not shown) 4 rf BPMs for incoming trajectory Ceramic gap w/ rf diode detectors (16 GHz, 23 GHz, and 100 GHz) and 2 EMI antennas M. Woods, SLAC Dipoles + Wiggler Downstream (not shown) Ceramic gap for EMI studies T 475 Detector for Wiggler SR stripe 4
Energy Spectrometer Magnets for 2007 Runs v 1 Dipole currently at Magnet Test Lab v 1 Dipole is installed on ESA Beamline M. Woods, SLAC 5
T 474: Resolution & stability within a BPM triplet old cavities 200 nm = 40 ppm Resolution : BPM 9 -11: ~350 nm in x BPM 3 -5: ~ 700 nm in x, lts u es ry) R a 06 imin 0 2 el (Pr <40 ppm stability for 20 k pulses ~ 30 min prototype 6
T 474: Resolution & Stability Linking BPM Stations in ESA BPMs 1 -2 Run 1333 BPMs 3 -5 Wake. Field Box BPMs 9 -11 4 chicane magnets will go in this region 30 meters v use BPMs 1 -2 and 9 -11 to fit straight line • predict beam position at BPMs 3 -5 • plot residual of BPM 5 wrt predicted position 0. 5 mm → 100 ppm Run 1333 s ult ) s Re nary 6 i 0 20 elim (Pr M. Woods, SLAC Why jumps and drifts in residuals when linking bpm stations? Investigate possibilities: • analysis bug? • changes in LO phase or BPM electronics? • bias related to change in beam trajectory, beam energy or other beam parameters? • relative alignment of bpm stations changed? → a primary purpose of T-474 is to investigate sensitivity of energy measurement to changes in beam parameters and electronics stability, and whether goals for systematic errors <100 ppm can be met 7
T 474: Resolution & Stability Linking BPM Stations → better stability on this run! Run 1458 s ult ) s Re nary 6 i 0 20 elim (Pr M. Woods, SLAC 8
Energy Spectrometer Tests: FY 07/08 Plans Ø Performance tests of realistic spectrometers • Install 4 chicane magnets and 1 wiggler Ø Investigate calibration procedures and systematics due • Move BPM 4 to BPM 6 location to BPM electronics stability, mechanical stability, • New BPM 7, design optimized for spectrometry magnetic fields, sensitivity to beam parameters • Operate chicane in both polarities Ø compare results from BPM, synch stripe msmts and • Install Metrology grid (staged approach) upstream beam diagnostics • Install Detector for Wiggler SR stripe BPM 6, 7 BPM 3, 5 BPM 9 -11 Vertical Wiggler Metrology Grid D 1 straightness monitor BPM Station D 2 D 3 D 4 BPM Station ~1 m “reference bar” Interferometer arms M. Woods, SLAC for triangulation. Contains internal interferometer for monitoring 9
Energy Spectrometer Tests: FY 07/08 Plans Ø Performance tests of realistic spectrometers • Install 4 chicane magnets and 1 wiggler Ø Investigate calibration procedures and systematics due • Move BPM 4 to BPM 6 location to BPM electronics stability, mechanical stability, • New BPM 7, design optimized for spectrometry magnetic fields, sensitivity to beam parameters • Operate chicane in both polarities Ø compare results from BPM, synch stripe msmts and • Install Metrology grid (staged approach) upstream beam diagnostics • Install Detector for Wiggler SR stripe BPM 6, 7 BPM 3, 5 BPM 9 -11 Vertical Wiggler D 1 3 D 2 D 3 D 4 Beam R. Arnold M. Woods, SLAC 10
T-480 Preliminary Results Sandwich 1 Collimators: Slot 1 a = 324 mrad r = 1. 9 mm (r = ½ gap) Slot 2 a = 324 mrad r = 1. 4 mm Slot 3 L=1000 mm a = 324 mrad r = 1. 4 mm Slot 4 a = p/2 r = 3. 8 mm 7 mm M. Woods, SLAC 11
T-480 Preliminary Results Collimator Measured 4 Kick Factor V/pc/mm (c 2/dof) Linear fit Measured 4 Kick Factor V/pc/mm (c 2/dof) Linear + Cubic Fit Analytic Prediction 1 Kick Factor V/pc/mm 3 -D Modelling Prediction 2 Kick Factor V/pc/mm 1 (Sand 1, Slot 1) 1. 4 ± 0. 1 (1. 0)3 1. 2 ± 0. 3 (1. 0) 1. 1 1. 7 2 (Sand 1, Slot 2) 1. 4 ± 0. 1 (1. 3) 1. 2 ± 0. 3 (1. 4) 2. 3 3. 1 3 (Sand 1, Slot 3) 4. 4 ± 0. 1 (1. 5) 3. 7 ± 0. 3 (0. 8) 6. 6 7. 1 4 (Sand 1, Slot 4) 0. 9 ± 0. 2 (0. 8) 0. 5 ± 0. 4 (0. 8) 0. 3 0. 8 5 (Sand 2, Slot 1) 1. 7 ± 0. 3 (2. 0) 1. 7 ± 0. 3 (2. 2) 2. 3 2. 4 6 (Sand 2, Slot 2) 1. 7 ± 0. 1 (0. 7) 2. 2 ± 0. 3 (0. 5) 2. 3 2. 7 7 (Sand 2, Slot 3) 0. 9 ± 0. 1 (0. 9) 0. 9 ± 0. 3 (1. 0) 2. 4 8 (Sand 2, Slot 4) 3. 7 ± 0. 1 (7. 9) 4. 9 ± 0. 2 (2. 6) 2. 3 6. 8 1 Assumes 500 -micron bunch length, includes analytic resistive wake; modelling in progress 3 Kick Factor measured for similar collimator described in SLAC-PUB-12086 was (1. 3 ± 0. 1) V/pc/mm 4 Still discussing use of linear and linear+cubic fits to extract kick factors and error bars 2 Assumes → Goal is to measure kick factors to 10% M. Woods, SLAC 12
T-480: FY 07/08 Plans 7 New Collimators for Run 3 will be fabricated and tested (keep 1 from Run 2 for cross check) Ø Compare importance of tapers in region away from gap centre – Ø acceptable to have shallow tapers necessary for transverse wakefield performance only in the immediate vicinity of beam axis? ? (Can we make much shorter collimators? ) Ø Flat section introduced equivalent in length to 0. 6 r. l. of Ti 6 Al 4 V Ø Explicit tests of surface roughness Ø Allow one slot for non-linear taper, exponential form Additional Collimators to test for Run 4 possible in FY 07 + plan to continue tests in FY 08 M. Woods, SLAC 13
Bunch Length Measurements vs Linac rf Phase Energy Spread 100 GHz Diode* short bunches w/ small energy spread Shorter bunches Li. Track Simulation Data Pyroelectric Detector* → sensitive to shorter bunches than 100 GHz diode! 23 GHz Diode* → insensitive to bunch length *normalized to toroid M. Woods, SLAC 14
Bunch Length Studies for 2007 1. Will continue collaborative effort with LCLS Ø test 300 -GHz diode detector Ø test large area pyroelectric detectors Ø discussing with F. Sannibale and M. Zolotorev at LBL & J. Frisch at SLAC possibility for bunch length measurements from analyzing statistical fluctuations in visible synchrotron radiation from T-475 wiggler magnet in energy spectrometer chicane → do this with T-490 beam? (this technique described in PRL 82, 5261 (1999) for 1 -5 ps bunches at 44 Me. V) 2. T-487 experiment with Smith-Purcell radiation M. Woods, SLAC 15
T 487: Longitudinal Bunch Diagnostics for the ILC Goal: non-invasive determination of longitudinal bunch profile • Fundamental beam quantity; important for beam-beam effects. Technique: Use Coherent Smith-Purcell radiation, emitted when a beam passes close to a periodic structure (i. e. a metallic grating). • Grating produces dispersion of the wavelengths according to the angle of observation. • Wavelength distribution of emitted coherent radiation depends on the temporal profile of the bunch Carousel of Gratings Simple experimental set-up: • ‘Carousel’ of 3 gratings with different periodicities. • Array of 11 room temperature pyroelectric detectors covering angular range 40 – 140 o w. r. t. the beam direction. Winston Cone Front View Optical system: • Waveguide Array Plate filter designed for a specific wavelength, attached to a light concentrator (Winston cone). • Filter and Winston cone suppress background radiation, while collecting and concentrating desired wavelengths onto the pyroelectric detectors. Waveguide Array Plate Filter M. Woods, SLAC 16
T 487: Longitudinal Bunch Diagnostics for the ILC PI: G. Doucas (Oxford U. ), Collaborating Institutions: U. of Oxford, Rutherford Appleton Lab, U. of Essex, Dartmouth College, SLAC T-487 at SLAC-ESA • access to a much higher energy beam, with a different bunch structure to previously used beams. • An improved electronics system has been implemented, separating the electronics from the detectors, so as to reduce X-ray interference. • Due to the higher energy and charge of the SLAC-ESA bunch, higher orders of Smith-Purcell radiation may be exploitable. o Data obtained from higher orders will extend the measured range of wavelengths and provide useful insights into Smith-Purcell theory itself. o New filters have been produced to explore these regions with our current gratings. • An analysis code is being developed, which will include Kramers-Kronig phase determination, in order to obtain a unique bunch profile from the measurements. • Envisage two experimental runs at ESA in 2007 and two in 2008. M. Woods, SLAC 17
Future for continuing this ILC Test Beam Program? FY 08 → continue program in ESA, requesting 4 weeks of Beam Tests → beam scheduling more difficult: priority for LCLS, also for SABER → reduced funding available (? ) from SLAC and ILC, but major installations are complete FY 09 and beyond (LCLS era, parasitic operation with PEP-II ends at end of FY 08) → ESA PPS upgrade needed for continued ESA operation → ILC beam instrumentation tests in SABER are possible → Study group looking at SLAC test beam capabilities with primary and secondary beams for Detector and MDI-related R&D -- topic for Fermilab ILC Detector Test Beam Workshop in January SABER ESA - assume SABER exists with bypass line and operational for beam tests by 2010 - parameters for primary beam can be similar to ILC for bunch charge, energy spread, bunch length. 28. 5 Ge. V energy. - limited space and infrastructure - should be able to carry out small scale tests, ex. tests for BPMs, bunch length detectors - unlikely to continue T-474/T-475 here; T-480 may be possible, but difficult - need to investigate capability for low-intensity secondary beams for ILC detector R&D • several possibilities exist for primary and secondary beams to ESA in LCLS era; most require PPS upgrade and some require pulsed magnets in Beam Switchyard • primary beam modes: i) high energy beam when LCLS not running, iii) extend SABER bypass line to ESA (expensive), iii) interleaved 10 Hz running using LCLS beam with pulsed magnets, • secondary beam modes: i) high energy beam when LCLS not running, ii) parasitic operation with LCLS using beam halo and production collimator in BSY, iii) extend SABER bypass line to ESA (expensive), iv) pulsed magnets in BSY using 10 Hz LCLS beam and BSY production collimator, M. Woods, SLAC 18
Future of SLAC Test Beams (cont. ) New SABER Task Force following the DOE and EPAC SABER reviews • revisit comparison between South Arc and B Target Room locations, + consider broader user community, in particular for ILC Ø need to give input to task force for ILC Detector, Accelerator and MDI Also, informal study group considering SLAC Test Beam capabilities and user needs for Detector and MDI-related Beam Tests • preparing internal working document on this • will participate in Fermilab ILC Detector Test Beam Workshop, Fermilab Jan. 17 -19 https: //conferences. fnal. gov/idtb 07/ • C. Hast, D. Mac. Farlane and M. Woods will attend • Carsten will give talk in Facilities session, “SLAC Beam Test Facility Status and Plans” • Mike will give talk in Beam Instrumentation and MDI session, “Experiments at ESA, SLAC” v 3 other talks in this session will also include information on the ESA test beam program (energy spectrometers, FONT, collimator R&D) M. Woods, SLAC 19
Summary (presented to EPAC review Dec. 5) Very successful program in 2006! • 4 weeks of beam tests for 7 experimental programs • 50 participants (32 users + 18 SLAC) from 18 institutions T-480 Collimator Wakefield Study • Results essential for ILC collimator design • Minimize risk for emittance degradation to IR and for achieving design luminosity T-474 and T-475 Energy Spectrometer Prototypes • Experimental results needed to demonstrate ability to meet design goals for precise energy measurements for the ILC physics program. FY 07 → strong program, with 5 weeks of Beam Tests planned FY 08 → continue program, requesting 4 weeks of Beam Tests → beam scheduling more difficult: priority for LCLS commissioning, also for SABER → reduced funding available (? ) from SLAC and ILC, but major installations are complete FY 09 and beyond (LCLS era, parasitic operation with PEP-II ends at end of FY 08) → ESA PPS upgrade needed for continued ESA operation → ILC beam instrumentation tests in SABER possible; need to investigate secondary beams → Study group looking at SLAC test beam capabilities with primary and secondary beams for Detector and MDI-related R&D (topic for Fermilab ILC Detector Test Beam Workshop in January) M. Woods, SLAC 20
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