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August 2005Snowmass Workshop IP Instrumentation Wolfgang Lohmann, DESY Measurement of: Luminosity (precise and fast) Energy Polarisation
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Precise Luminosity Measurement IP VTX FTD 300 cm BeamCal L* = 4m Accuracy (from Physics) O(<10 -3 ) Gauge process: Bhabha Scattering Device: LumiCal 26 < < 82 mrad Beampipe
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Inner Radius of Cal.: < 4 μm Distance between Cals.: < 100 μm Radial beam position: < 0.6 mm Requirements on Alignment and mechanical Precision (MC simulations, BHLUMI) LumiCal IP Requirements on the Mechanical Design < 4 μm < 0.6 mm
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Beam Tilt Beam Size No effect
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Constant value value of the constant 0.11e-3 rad 0.13e-3 rad 30 layers 15 rings 20 rings 10 rings 4 layers 15 layers 11 layers 10 rings Performance Simulations for e + e - e + e - ( ) Event selection: acceptance, energy balance, azimuthal and angular symmetry. Simulation: Bhwide(Bhabha)+CIRCE(Beamstrahlung)+beamspread More in the talks by Halina Abramowicz
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20 mrad crossing angle Beamstrahlung pair background using serpentine field 250 GeV Number of Bhabha events as a function of the inner Radius of LumiCal Background from beamstrahlung A design for 20 mrad crossing angle will be done (needs time)
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Decouple sensor frame from absorber frame Sensor carriers Absorber carriers Concept for the Mechanical Frame
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Fast Lumi Measurement and Beam Diagnostics Use Electrons from Rad. Bhabha events
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Trajectories of off momentum electrons in the first dublett Energy and spatial distributions Fast Lumi Measurement and Beam Diagnostics Needs a spectrometer there
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Fast Lumi Measurement and Beam Diagnostics
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15000 e + e - per BX 10 – 20 TeV (10 MGy per year) e + e - Pairs from Beamstrahlung are deflected into the BeamCal GeV direct Photons for < 200 rad Zero (or 2 mrad) crossing angle 20 mrad Crossing angle Beam Parameter Determination with BeamCal
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total energy first radial moment thrust value angular spread L/R, U/D F/B asymmetries Observables Quantity Nominal Value Precision xx 553 nm1.2 nm yy 5.0 nm0.1 nm zz 300 m4.3 m yy 00.4 nm Beam Parameter Determination with BeamCal zero or 2 mrad Crossing angle √s = 500 GeV
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Quantity Nominal Value Precision xx 553 nm4.8nm yy 5.0 nm0.1 nm zz 300 m11.5 m yy 02.0nm Beam Parameter Determination with BeamCal PRELIMINARY! 20 mrad crossing angle total energy first radial moment thrust value angular spread L/R, U/D F/B asymmetries Also simultaneous determination of several beam parameter is feasible, but: Correlations! Analysis in preparation Observables
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Beam Parameter Determination with BeamCal
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nominal setting (550 nm x 5 nm) >100m IP L/R, U/D F/B asymmetries of energy in the angular tails Quantity Nominal Value Precision xx 553 nm4.2 nm zz 300 m7.5 m yy 00.2 nm Heavy gas ionisation Calorimeter and with PhotoCal Photons from Beamstrahlung
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Heavy crystals W-Diamond sandwich sensor Space for electronics Technologies for the BeamCal: Radiation Hard Fast Compact
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Detection of High Energy Electrons and Photons (Detector Hermeticity) √s = 500 GeV Single Electrons of 50, 100 and 250 GeV, detection efficiency as a function of R ( ‘ high background region ’ ) (talk by V. Drugakov and P. Bambade) Detection efficiency as a function of the pad-size (Talk by A. Elagin) Message: Electrons can be detected! Red – high BG blue – low BG
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Includes seismic motions, Delay of Beam Feedback System, Lumi Optimisation etc. (G. White) Efficiency to identify energetic electrons and photons (E > 200 GeV) Fake rate √s = 500 GeV Realistic beam simulation Detection of High Energy Electrons and Photons
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Sensor prototyping, Diamonds ADC Diamond (+ PA) Scint.+PMT& signal gate May,August/2004 test beams CERN PS Hadron beam – 3,5 GeV 2 operation modes: Slow extraction ~10 5- 10 6 / s fast extraction ~10 5 -10 7 / ~10ns (Wide range intensities) Diamond samples (CVD): - Freiburg - GPI (Moscow) - Element6 Pm1&2 Pads
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Linearity Studies with High Intensities (PS fast beam extraction) 10 5 particles/10 ns Response to mip Diamond Sensor Performance
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Upstream momentum spectrometer
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ESA Test Beam Plans for 2005/2006 2x10 10 electrons per bunch @ 28.5 GeV (ILC buch charge and length) Compare different measurments (this spectrometer, A- line BPMs, Synchrotron spectrometer) Accuracy goal: < 100 ppm Proof of principle!
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Energy Measurement Downstream SR spectrometer Energy spectrum After bunch crossing Goals: peak position, width, tail
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Downstream SR spectrometer
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Upstream polarimeter Polarimetry Document on polarimetry design in Feb 2006 + Downstream polarimeter
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The needs from Detector and Machine side are different. Lets find solutions
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