energy spectrometer for the ilc
DESCRIPTION
Energy Spectrometer for the ILC. Alexey Lyapin University College London. BPM energy spectrometer collaboration. UCL: Filimon Gournarnis, Alexey Lyapin, Matthew Wing Cambridge: Mark Slater, David Ward RHUL: Stewart Boogert DESY-Zeuthen: Heinz-Jeurgen Schreiber, Michele Viti - PowerPoint PPT PresentationTRANSCRIPT
Energy SpectrometerEnergy Spectrometerfor the ILCfor the ILC
Alexey LyapinAlexey Lyapin
University College LondonUniversity College London
EUROTeV meeting, LAL,May 2006 2
BPM energy spectrometer BPM energy spectrometer collaborationcollaboration
UCL: Filimon Gournarnis, Alexey Lyapin, Matthew WingUCL: Filimon Gournarnis, Alexey Lyapin, Matthew Wing
Cambridge: Mark Slater, David WardCambridge: Mark Slater, David Ward
RHUL: Stewart BoogertRHUL: Stewart Boogert
DESY-Zeuthen: Heinz-Jeurgen Schreiber, Michele VitiDESY-Zeuthen: Heinz-Jeurgen Schreiber, Michele Viti
JINR (Dubna): Viktor Duginov, Nikolay MorozovJINR (Dubna): Viktor Duginov, Nikolay Morozov
In collaboration with SLAC, KEK, UC Berkley, LLNL, BINP…In collaboration with SLAC, KEK, UC Berkley, LLNL, BINP…
EUROTeV meeting, LAL,May 2006 3
Luminosity spectrumLuminosity spectrum
Precision threshold scan Precision threshold scan measurements:measurements:
Energy loss effects have to Energy loss effects have to be taken into accountbe taken into account
Absolute beam energy Absolute beam energy measurement of 1 part in 10measurement of 1 part in 1044
Spectrometers up- and Spectrometers up- and downstreamdownstream
EUROTeV meeting, LAL,May 2006 4
BPM spectrometer BPM spectrometer requirementsrequirements
ChicaneChicane 4 magnets 4 magnets 5 mm maximum 5 mm maximum
deflectiondeflection Bipolar operationBipolar operation
Measurement timeMeasurement time Single bunchSingle bunch Bunch trainBunch train 1 hour / 1 day1 hour / 1 day
Dipole magnet
BPM triplet
Mode of operation affects BPM Mode of operation affects BPM designdesign Operation of chicane (frequency Operation of chicane (frequency
of ramping)of ramping) Frequent return to low energy?Frequent return to low energy? Essential design beam energiesEssential design beam energies
50, 175, 250 & 500 GeV50, 175, 250 & 500 GeV Move BPMs to null dipole signalMove BPMs to null dipole signal
Single bunch information useful for Single bunch information useful for machine operation?machine operation?
EUROTeV meeting, LAL,May 2006 5
BPMs in the spectrometerBPMs in the spectrometer
Essential part of diagnosticEssential part of diagnostic 9 BPMs per spectrometer x 4 beam lines 9 BPMs per spectrometer x 4 beam lines
~36 BPMs~36 BPMs Requirements different from Linac BPM Requirements different from Linac BPM
requirementsrequirements Requires detailed design work nowRequires detailed design work now
EUROTeV meeting, LAL,May 2006 6
Spectrometer BPM Spectrometer BPM requirementsrequirements
Spectrometer BPM will probably set Spectrometer BPM will probably set the most stringent requirements on the most stringent requirements on BPM designBPM design ApertureAperture Resolution Resolution Dynamic range (1000:1)Dynamic range (1000:1) Stability (intrinsic and Stability (intrinsic and
electronics)electronics) AccuracyAccuracy CalibrationCalibration BackgroundsBackgrounds
Existing BPM designs are far from Existing BPM designs are far from optimal for an energy spectrometeroptimal for an energy spectrometer Button and strip-line not Button and strip-line not
seriously consideredseriously considered ATF/ATF2 - aperture ATF/ATF2 - aperture Reentrant resolution/stability?Reentrant resolution/stability? Generic pill box cavityGeneric pill box cavity
MachineMachine Bunch angle, position & charge Bunch angle, position & charge
jitterjitter ApertureAperture
SpectrometerSpectrometer Movement rangeMovement range
Stray fieldsStray fields Emittance dilutionEmittance dilution
BPMBPM Resolution already achieved Resolution already achieved
(See ATF results)(See ATF results) Scaling of resolution as function Scaling of resolution as function
of cavity sizeof cavity size Design for stability (monopole Design for stability (monopole
rejection)rejection)
EUROTeV meeting, LAL,May 2006 7
NanoBPM collaboration at NanoBPM collaboration at ATFATFKEK BPMs on flexure piezo moversKEK BPMs on flexure piezo movers BINP BPMs in SLAC/LLNL frameBINP BPMs in SLAC/LLNL frame
Experiment to test the best BPM resolution among with Experiment to test the best BPM resolution among with the other BPM properties, systematics and stabilitythe other BPM properties, systematics and stability
EUROTeV meeting, LAL,May 2006 8
Results from ATFResults from ATF April 2006 dataApril 2006 data
Fitting algorithmFitting algorithm Calibration using hexapod Calibration using hexapod
moversmovers Resolution for the best Resolution for the best
runs ~ 18 nmruns ~ 18 nm Short and long term drifts Short and long term drifts
less than 100 nmless than 100 nm LO sources locking LO sources locking
improvedimproved KEK BPMs coupling to the KEK BPMs coupling to the
reference cavity fixedreference cavity fixed Cross-calibration with Cross-calibration with
corrector magnetscorrector magnets
EUROTeV meeting, LAL,May 2006 9
SLAC ESA spectrometer SLAC ESA spectrometer activitiesactivities
Two more runs next year Two more runs next year with magnets installedwith magnets installed
Planning to add/replace Planning to add/replace BPMs around 2007 with BPMs around 2007 with higher resolution ones higher resolution ones now designed in UCLnow designed in UCL
One of the primary tests is a 4-One of the primary tests is a 4-magnet chicane spectrometermagnet chicane spectrometer
High energy beam testHigh energy beam test Commissioning run in Jan 2006 to Commissioning run in Jan 2006 to
test the BPMs and electronics, other test the BPMs and electronics, other diagnostics installeddiagnostics installed
Preliminary old (not nano-) cavity Preliminary old (not nano-) cavity BPM resolution with the new BPM resolution with the new electronics ~1electronics ~1μμmm
EUROTeV meeting, LAL,May 2006 10
End station A programeEnd station A programe
Plans to test chicane ideas at ESAPlans to test chicane ideas at ESA Using old SLAC cavities Using old SLAC cavities Test of chicane ideas and Test of chicane ideas and
identification of possible identification of possible problems problems
Test system of other general ILC Test system of other general ILC and spectrometer specific BPM and spectrometer specific BPM designs designs
New RF electronicsNew RF electronics Resolution ~1Resolution ~1mm
First tests in January and April 2006, First tests in January and April 2006, chicane tests in 2007…chicane tests in 2007…
EUROTeV meeting, LAL,May 2006 11
Results from ESAResults from ESA Commissioned 2 BPM Commissioned 2 BPM
triplets, including the triplets, including the new Linac BPMsnew Linac BPMs
Resolution dataResolution data Resolutions of <1Resolutions of <1µm µm
were achievedwere achieved Dynamic range Dynamic range
+/- 1 mm+/- 1 mm Resolution of the Resolution of the
Linac BPMs still Linac BPMs still worse (few µm), worse (few µm), should improve should improve significantly with the significantly with the analysis tuned to the analysis tuned to the different decay different decay rate/bandwidthrate/bandwidth
EUROTeV meeting, LAL,May 2006 12
Results from ESAResults from ESA
BPM alignmentBPM alignment 3 sets aligned within +/- 200 3 sets aligned within +/- 200 µmµm Distance between sets ~20 mDistance between sets ~20 m
EUROTeV meeting, LAL,May 2006 13
Need optimized BPM designNeed optimized BPM design
Cavity BPMs, no alternative yetCavity BPMs, no alternative yet Positive experience with ATF/ATF2 cavitiesPositive experience with ATF/ATF2 cavities Need a bigger aperture for machine Need a bigger aperture for machine
protectionprotection Scale ATF2 design to a lower frequencyScale ATF2 design to a lower frequency
EUROTeV meeting, LAL,May 2006 14
ATF2 QBPMsATF2 QBPMs
First nanoBPM for First nanoBPM for serial production! serial production! (~30 units to be (~30 units to be produced for produced for ATF2)ATF2)
Electrical design done by UCLElectrical design done by UCL Several prototypes successfully testedSeveral prototypes successfully tested Good performance observedGood performance observed At least 40 dB isolation between x and At least 40 dB isolation between x and
y channels measured after tuningy channels measured after tuning Successful tests with dedicated Successful tests with dedicated
electronicselectronics
EUROTeV meeting, LAL,May 2006 15
2.8 GHz cavity design in 2.8 GHz cavity design in progressprogress
Robustness vs. high sensitivity and Robustness vs. high sensitivity and compactness optimumcompactness optimum
Tuning to 2876 MHzTuning to 2876 MHz Reduced Q to keep the decay time Reduced Q to keep the decay time
smallsmall Use nanoBPM analysis – keep similar Use nanoBPM analysis – keep similar
processed signal propertiesprocessed signal properties Almost the same sensitivity as for Almost the same sensitivity as for
BPMs in nanoBPM experiment at ATF BPMs in nanoBPM experiment at ATF beam, expect a resolution < 100 nmbeam, expect a resolution < 100 nm
Planning to test in ESAPlanning to test in ESA
EUROTeV meeting, LAL,May 2006 16
Prototype Al modelPrototype Al model
Planning to do cold tests before producing a vacuum prototype, a model is Planning to do cold tests before producing a vacuum prototype, a model is being produced in UCL workshopbeing produced in UCL workshop
Going to introduce an asymmetry (one slot will be off axis), also reduced the Going to introduce an asymmetry (one slot will be off axis), also reduced the waveguide length in order to see the monopole mode coupling; this should waveguide length in order to see the monopole mode coupling; this should allow us to set reasonable tolerances, benchmark the simulation code, and allow us to set reasonable tolerances, benchmark the simulation code, and choose a reasonable waveguide lengthchoose a reasonable waveguide length
EUROTeV meeting, LAL,May 2006 17
ILC spectrometerILC spectrometerSpectrometer analysis:Spectrometer analysis: Started with a simulation of Started with a simulation of
systematic effects in the systematic effects in the spectrometer chicanespectrometer chicane
Backgrounds simulationBackgrounds simulation Improving existing analysis of Improving existing analysis of
the impact of the spectrometer the impact of the spectrometer chicane on the beam (energy chicane on the beam (energy bandwidth etc)bandwidth etc)
Joined the efforts with all Joined the efforts with all European institutions involvedEuropean institutions involved