the star-rich
DESCRIPTION
The STAR-RICH. Gerd J. Kunde, Yale. Background Transition Performance. Measurements Summary. STAR Au+Au Central Collision at 200 GeV. TPC. RICH. STAR-RICH. The STAR-RICH The HMPID Prototype. Device Characteristics construction components Heavy Ion Environment - PowerPoint PPT PresentationTRANSCRIPT
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The STAR-RICH Gerd J. Kunde, Yale
Background Transition Performance
Measurements Summary
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The STAR-RICHThe HMPID Prototype
• Device Characteristics– construction– components
• Heavy Ion Environment
• Particle Identification
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Device Characteristics
• Extend PID beyond TPC TOF:
1 < p < 3 GeV/c K 2 < p < 5 GeV/c p
• 160 x 85 cm2 1.2 m2
• Radial Distance of 2.4 m• |y| < 0.2
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Components
• Radiator
– C6F14 Liquid
• Photo Converter– CsI– < 210 (nm)
• Ionization Detector– MWPC pad chamber
– CH4 Gas
80 mm
• Developed by CERN RD-26 in ALICE framework headed by F. Piuz, E. Nappi
• ALICE RICH Prototype Module (1.2 m2)
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STAR-RICH PicturesBari/Cern/Yale STAR-RICH Collaboration
• RICH at CERN : Testbeam Setup in ‘98
• RICH at BNL: Installation into STAR Magnet in ‘99
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Response to BNL Safety Review :-(
• RICH in Aluminum Safety Box
• Buffer Volume N2
• Temperature probes under Slow Control
• Gas detectors have be calibrated to Methane
• Closed Liquid System– Transfer of liquid
under nitrogen• Construction of NEW
LV Distribution Boards made with FR4
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Mechanical Design Completed in ‘99
• RICH• Safety Box with
Nitrogen Flow• 5 o’clock West• Width: 7 Rails• Cables/Tubes in
Trays
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Mechanical Design
• Safety Box – Gas Flow with
Nitrogen– Front Panel– Back Panel
• Thermal Shield– Kinematic Mount
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Gas System • Relative Pressures
Regulated by Bubblers• Chamber
– 2.3 mbar CH4
– 3.1 mbar Ar• Safety Box
– 1.8 mbar
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Gas Requirements and Shipment
• O2 & H2O hazardous to CsI
• Must Deliver Clean Anhydrous Gas
– CH4 Flow Rate of 30 l hr-1
– Ar Purge/Buffer Flow at 60 l hr-1
Exposure Limits Test Allowed Shipment
talk to F. Piuz to hear the fun details
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• CsI Photo-Converter– Vacuum Ultra-Violet (VUV)
• Liquid Radiator
– ~100L of C6F14
– Closed Recirculation/Cleaning– VUV Transparency Monitor
Liquid System
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Liquid System II
• Inert Liquid– Fluoro Inert PF5060DL
• Closed Recirculation System
• Gravity Feed to/from Distribution Rack
• SS Pipes • 3 Overpressure Relief
Valves
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Slow Control
• EPICS– Temperatures– HV-System– LV-System
• Gas System– Alan Bradley PLC– Interlock– EPICS Control
• Liquid System– Siemens PLC
• VME-Scalers
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Electronics• GASSIPLEX CMOS 1.5 m technology
– Charge Pre-amp, Shaper, and Track and Hold Stage– Pad Readout ONLY– 11 bit Dynamic Range .17 fC/channel
• Event Rate allows 700 ns Integration– Multiplexed 16 Analog Channels MCM
• STAR Trigger Rate few Hz• STAR-L0 at 1.8 microseconds !• Fast Clear Logic with Pretrigger !
– Heat Generation • 6mW channel-1 => ~100 W/16k channels
• concern for liquid dn/dT = 5x10-4 oC-1
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Photo Electrons
Charged Particles
Pad Chamber
• 2-D Cathode Pad Readout
– 500 nm CsI Layer on Pads
• 8.0 x 8.4 mm2
• 15360k pads
• Dynamic Range
– Single Electron
– MIP detection
– Chamber Stability
– Ambient Pressure :-)
• CH4 Chamber Gas
– Quenching
– High Photo-Electron Emission Efficiency
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Radiator• Liquid C6F14
– Index of Refraction 1.29
– pth = 1.26 mc (GeV/c)
• Match Spectral Sensitivity of CsI
Ring Radii * Proximity Focussing * Normally Incident Tracks
p
K
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Clean Liquid !
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How long it takes to get there ....
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Determination of Cherenkov Angle
• Cern Test Beam Determination– 350 GeV/c -
– Normal Incidence • Resolution– 12.0 mrad single – 3.0 mrad ring average
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Alignment in STAR
• Track Extrapolation drift = 2.7 mm
bend = 3.1 mm
• Near Expected Resolution– 8.0 x 8.4 mm2 pads – 4 mm anode wire pitch– 2 mm anode-cathode
spacing
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The STAR Environment
• Effect of:
– Track Incidence Angle
– Proximity Focussing
Normal Incidence
10o Incidence
20o Incidence
• Ring Azimuth Angles• 180o
• 90o
• 60o
Cherenkov Light is Internally Reflected at an Angle of ~10o
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Golden Event
• Illustrative Example• Separation Possible
– Signal/Background is Large
– Proximity Focussing produces “Rings”
• Both Pion and Kaon Emerge
• Size of MIP and
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Event Characteristics
PeripheralCentral
more central
PixelOccupancy
<5%
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Separation Achieved !
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Number of Photons in Real Analysis
Average Number is limited due to Incident Angle Range
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Summary
• STAR-RICH project has been extremely successful– Prototype RICH Chamber in Operation at STAR– Performance as Expected– Two Successful Physics Runs– Stable Operation over 3 years !
• Particle Identification– Consistent Results– Controlled Systematics– Not just Detector Test but Physics !
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STAR Collaborators/Institutions
Brazil: Universidade de Sao Paolo
China: IHEP - Beijing, IPP - Wuhan
England:
University of Birmingham
France:
Institut de Recherches Subatomiques Strasbourg, SUBATECH - Nantes
Germany:
Max Planck Institute Munich, University of Frankfurt
India: Institute of Physics - Bhubaneswar, VECC
Calcutta, Panjab University - Chandrigrarh, University of Rajasthan - Jaipur, Jammu University, IIT -Bombay
Poland:
Warsaw University, Warsaw University of Technology
Russia:
MEPHI – Moscow, LPP/LHE JINR – Dubna, IHEP - Protvinoh
U.S. Universities:
Arkansas, UC Berkeley, UC Davis, UCLA,
Carnegie Mellon, Creighton, Indiana, Kent
State, MSU, CCNY, Ohio State, Penn State,
Purdue, Rice, Texas A&M, UT Austin,
Washington, Wayne State, Yale
U.S. Labs:
Argonne, Berkeley, and Brookhaven
National Laboratories
~400
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STAR-RICH Collaboration
• Y.Andres1, A.Braem1, M.Calderon2, N.Colonna3, D. Cozza3 , M.Davenport1, L. Dell’Olio3, D. DiBari3, A. DiMauro1, J.C.Dunlop2, D.Elia3, E.Finch4, R.Fini3, D. Fraissard1, B.Ghidini3, B. Goret1, R.Gregory1, J.W.Harris2, M.Horsley2, G.J.Kunde2, B.Lasiuk2, Y. Lescenechal1, R.D.Majka4, P.Martinengo1, A.Morsch1, E.Nappi3, G.Paic1, F.Piuz1, F.Posa3, J.Raynaud1, J.Sandweiss4, J.C.Santiard1, E.Schyns1, N.Smirnov2, S.Stucchi3, G.Tomasicchio3, J. Van Beelen1, T.D. Williams1, Z. Xu4
1 CERN HMPID Group
2 Yale Relativistic Heavy Ion Group
3 Bari HMPID Group
4 Yale High Energy Group
My Personal Special Thanks to F. Piuz !!!!!!!!!!!!