March 22, 2011Mike Hildreth – ALCPG 2011, Beam Instrumentation Energy Spectrometer R&D; Plans for End Station A Test Beams Mike Hildreth University of Notre Dame ALCPG, March 22, 2011

March 22, 2011Mike Hildreth – ALCPG 2011, Beam Instrumentation Precision Beam Measurements Precision Physics Measurements require precise determination of beam parameters – How well do we have to do? Luminosity, Differential Luminosity Spectrum: –Total cross sections:  L/L ~ 0.1% –Lineshape scans (Giga-Z)  L/L ~ 0.02% –Threshold scans (e.g., m top )  L/L ~ 1%, but additional constraints: dL/dE core to 0.1%, tails to ~1% Energy: –top, higgs masses<100 ppm –W mass with threshold scan50 ppm (4 MeV) –A LR with Giga-Z200 ppm (comparable to 0.25% Pol) 50 ppm (if  P/P ~ 0.1%) Polarization: –Standard Model Asymmetries  P/P < 0.25% –A LR with Giga-Z  P/P < 0.1%

March 22, 2011Mike Hildreth – ALCPG 2011, Beam Instrumentation Energy Measurements A few words of Motivation... –Energy Calibration needs for Physics at a future Linear Collider will be similar to what we had at LEPII: Threshold Scans : Kinematic Fits:

March 22, 2011Mike Hildreth – ALCPG 2011, Beam Instrumentation Prototypical Energy Spectrometers “LEP-Type”: BPM based, bend angle measurement “SLC-Type”: SR stripe based, bend angle measurement BPMs p  “upstream”  “downstream” Aim for Energy Measurement

March 22, 2011Mike Hildreth – ALCPG 2011, Beam Instrumentation e.g.: “ILC” Upstream Energy Spectrometer Pure “Displacement” Strategy: Prototype Design –ILC design: total length of chicane = 54.4 m –dispersion at center = 5mm (~equal to beam displacement) so, 0.5  m BPM resolution gives 1x10 -4 measurement (per pulse) –CLIC Chicane requires 100nm resolution/stability –Designs incorporated into Accelerator Lattices Incoming Beam Central BPMs measure offset, offset difference between ±B (cancel some systematic errors) Outer BPMs required to constrain beam trajectory all magnets run to ±B 5 mm better resolution would allow intra-train bunch energy measurements M. Hildreth (Notre Dame), SLAC

March 22, 2011Mike Hildreth – ALCPG 2011, Beam Instrumentation History: ESA Test Beam Experiments 1.BPM Energy Spectrometer (T-474/491) PIs: M. Hildreth, Notre Dame, S. Boogert, Royal Holloway, Y. Kolomensky, Berkeley/LBNL Institutions: Cambridge, DESY, Dubna, Royal Holloway, Notre Dame, UCL, Berkeley, SLAC –Goals: Demonstrate mechanical and electrical stability at 100-nm level Perform energy measurement in 4-magnet chicane Develop calibration techniques, operational procedures –multiple BPM triplets to test overall stability, new BPM designs 2.Synchrotron stripe diagnostics (T-475) PI: E. Torrence, Oregon Institutions: Oregon, SLAC –Goals: test chicane scheme with wiggler magnet characterize detector (quartz fiber / other) performance and capabilities Overall Goal: perform cross-check of two energy measurements at the ~10 -4 level

March 22, 2011Mike Hildreth – ALCPG 2011, Beam Instrumentation T474 (T491), T475: Energy Spectrometers BPM-based and Synchrotron-Stripe Spectrometers can be evaluated in a common four-magnet chicane Dipole BPMs Wiggler Synchrotron Stripe Detector

March 22, 2011Mike Hildreth – ALCPG 2011, Beam Instrumentation FY07 Configuration Ran in 2006 with no dipole chicane Runs in March, July 2007 with chicane Simultaneous test of BPM and Synchrotron Stripe Spectrometers –first beam tests for Synchrotron Detector –compare measured energy, energy jitter at ppm level –tests of BPM movers –more elaborate mechanical stability monitoring Dipoles Wiggler BPMs Interf. Station Straightness Monitor

March 22, 2011Mike Hildreth – ALCPG 2011, Beam Instrumentation Energy Measurement with chicane (2007) Beam energy computed from spectrometer  Bdl and BPM offset measurement vs. time –energy variation from linac energy scan –large pulse-to-pulse jitter Residual between predicted and measured BPM position at chicane center gives a value  E ~16 MeV (  E/E ~ 5.5×10 -4 ) need higher-precision test A. Lyapin et al., “Results from a Prototype Chicane-Based Energy Spectrometer for a Linear Collider”, JINST 6 (2011) P02002.

March 22, 2011Mike Hildreth – ALCPG 2011, Beam Instrumentation Mechanical Stability Stability requirements determined by overall BPM resolution needed Mechanical support structure must be designed to limit vibration, and with minimal thermal expansion properties –Custom temperature regulation needed... Stability must be monitored: Interferometry-based system Zygo 4004 Measurement System –Design Specs: 0.3 nm single-bit resolution at up to 5 m/s velocity single measurement ~ 7nm BPM Local motion measurement Interferometer heads Long Baseline Monitoring

ATF2 Installation As of October 2010: three interferometers monitoring three BPMs March 22, 2011Mike Hildreth – ALCPG 2011, Beam Instrumentation QD10BQD10AQM11QM12QM13QM14 BPM BPM MFB2 Optical Path optical path uses clearance between mover rollers underneath quads BPMs MFB2 and QD10B are part of vertical steering feedback for beam stability at ATF2 IP. Need resolution  stability of ~ 50nm

Results from ATF2 March 22, 2011Mike Hildreth – ALCPG 2011, Beam Instrumentation data acquisition at 1 kHz vibration data on BPM QD10B. rms = 35nm 36-hour drift on BPM QD10B. scale is nm. one micron Time (sec) interferometer retroreflector CCD camera QD10B

Results from ATF2 March 22, 2011Mike Hildreth – ALCPG 2011, Beam Instrumentation 50 micron FFTB mover calibration step “Relaxation” of mechanical position of BPM MFB2 after calibration move, measured by interferometer No corresponding drift seen simultaneously on other BPM support with no mover motion analysis ongoing to trace relative beam/BPM motion to prove that this is a physical movement Time (sec) “Features” of FFTB mover stability: BPM MFB2 ZYGO MFB2 position (nm) position (  m) position (nm) 500nm (other studies ongoing: CCD camera stability, interferometer triplet stability/resolution, etc.)

End Station A Plans/Schedule News from ESTB (End Station Test Beam) Workshop at SLAC, March 17, 2011 –many participants: global interest in high-purity electron test beam March 22, 2011Mike Hildreth – ALCPG 2011, Beam Instrumentation 0.25 nC ParametersBSYESA Energy13.6 GeV Repetition Rate5 Hz Charge per pulse0.25 nC Energy spread,  E  /E 0.058% Bunch length rms 10  m280  m Emittance rms (  x  y ) (1.2, 0.7) m-rad(4, 1) m-rad Spot size at waist (  x,y  - < 10  m Drift Space available for experimental apparatus -60 m Transverse space available for experimental apparatus -5 x 5 m M. Pivi, SLAC

End Station A Plans/Schedule 4 new kicker magnets including power supplies and modulators and vacuum chambers are designed and components are being ordered and manufactured Build new PPS system and install new beam dump March 22, 2011Mike Hildreth – ALCPG 2011, Beam Instrumentation

End Station A Plans/Schedule The complete 4 kickers system will not be ready until the end-of- summer Short-term solution, installed ~now –1 Kicker magnet with stainless steel chamber –Beryllium target –System designed for 60 Hz, might work at 120 Hz –Capacity: 4 GeV full intensity LCLS beam into ESA GeV primary beam into target and generate secondary e- beam to ESA, 0.1/pulse to 10 9 /pulse. By November 2011: Installation of the full 4 kicker magnet system to direct the LCLS beam in ESA. –Full 14 GeV LCLS beam into ESA –Production of secondary electron beam down to 1 e- / pulse. –Future (unfunded) option: secondary hadron beams March 22, 2011Mike Hildreth – ALCPG 2011, Beam Instrumentation

End Station A Plans/Schedule Critical (for Spectrometers and other tests): need precision BPMs –previous BPM sets no longer available –discussion with LCLS-II, other international sources ongoing LCLS-II and Korean FEL both need new precision BPMs maybe some joint venture that involves loaning BPMs to ESA for testing and commissioning before they are needed for light sources –would provide uniform high-precision installation, which would be very beneficial for understanding the analyses –time-early would be end of 2012 March 22, 2011Mike Hildreth – ALCPG 2011, Beam Instrumentation

Summary Termination of ESA program in 2008 limited the current level of precision for spectrometer testing to  E/E ~ 5.5×10 -4 –factor 5 larger than what is needed –will need to revitalize the End Station setup to improve on this ATF2 installation exploring stability issues at the 100nm level –50nm BPM resolution plus 7nm interferometer resolution plus ~100nm long-range stability monitoring is a powerful system to constrain mechanical motion –analysis needed! ESA Returns! –BPMs needed –probably 2012 before spectrometer tests can be mounted March 22, 2011Mike Hildreth – ALCPG 2011, Beam Instrumentation

March 22, 2011Mike Hildreth – ALCPG 2011, Beam Instrumentation Interferometer Data from End Station Vibrations with amplitudes close to or exceeding expected BPM resolution seen on support girder Synchronous data acquisition allows interferometer measurement of BPM position to be subtracted in later data analysis Resolution of central BPM improved by ~700nm (added in quadrature) after vibration subtraction BPM support girder clearly needs to be redesigned if we want to do any sort of stability testing nm condense

March 22, 2011Mike Hildreth – ALCPG 2011, Beam Instrumentation BPM Performance and Stability (2006)  ~ 350nm  ~ 700nm Stability of predicted position 100nm Residual  m

March 22, 2011Mike Hildreth – ALCPG 2011, Beam Instrumentation Upstream Energy Spectrometer Design Details: –Constrained by allowed emittance growth from Synchrotron Radiation hard bending at points of large dispersion gives large emittance growth  Any bend magnets inside chicane need to be “soft” –Constrained by available real estate in Beam Delivery Syst, overall size Relative positions of components need to be monitored –limits total size to ~50 m These constraints determine needed BPM resolution/stability –overall design for BPM resolution of ~0.5  m –can always average over many pulses if things are stable –if we do much better, bunch-by-bunch diagnostics possible –Other issues drive systematic errors, diagnostics  Complicated dependence on design parameters, options –Must be robust, invisible to luminosity M. Hildreth (Notre Dame), SLAC, Cambridge, UCL, Royal Holloway, LBNL/Berkeley, DESY-Zeuthen, Dubna

March 22, 2011Mike Hildreth – ALCPG 2011, Beam Instrumentation Interferometer Installation July 2006 March 2007

March 22, 2011Mike Hildreth – ALCPG 2011, Beam Instrumentation BPMs and Electronics Linac rf cavity BPM ILC Linac BPM SLAC Linac BPMs form main component of instrumentation –new electronics developed by Y. Kolomensky (Berkeley/LBNL)(LCRD Accelerator R&D) Also testing prototype ILC Linac BPMs developed at SLAC (C. Adolphsen) New BPMs, optimized for energy spectrometer, designed at University College London in collaboration with BPM experts at SLAC and KEK –custom electronics –mover system –July 2007

March 22, 2011Mike Hildreth – ALCPG 2011, Beam Instrumentation Beamline Components Dipoles: Measured in SLAC Magnet Lab prior to installation (SLAC/Dubna/Zeuthen) –RMS Reproducity of field integral: 60ppm –RMS Agreement across working points: 100ppm –Temperature coefficient: 5.7x10 -5 /°C –Excellent agreement between measured and simulated magnet properties –Also: measurements made of residual magnetic fields along entire beamline (  Bdl ~ 3 Gm) Wiggler refurbished – now installed

March 22, 2011Mike Hildreth – ALCPG 2011, Beam Instrumentation Interferometer Installations July 2006 March 2007 single BPM stationlink two BPM stations