The STAR-RICH

1
The STAR-RICH
Gerd J. Kunde, Yale

• Background
• Transition
• Performance

• Measurements
• Summary

2
STAR AuAu Central Collision at 200 GeV
TPC
RICH
STAR-RICH
3
STAR Detector (year-by-year)

• 1st year detectors (2000) year-by-year
  implementation until 2003
• 2nd year detectors (2001)

Coils
Silicon Strip Detector
Silicon Vertex Tracker
TPC Endcap MWPC
Forward Time Projection Chambers
Photon Multiplicity Detector
ZeroDegree Calorimeter
ZeroDegree Calorimeter
Endcap Calorimeter
Barrel EM Calorimeter
Central Trigger Barrel
TOF patch
RICH
4
The STAR-RICHThe HMPID Prototype

• Device Characteristics
• construction
• components
• Heavy Ion Environment
• Particle Identification

5
Device Characteristics

• Extend PID beyond TPC TOF
• 1 lt p lt 3 GeV/c p K
• 2 lt p lt 5 GeV/c p

• 160 x 85 cm2 ? 1.2 m2
• Radial Distance of 2.4 m
• y lt 0.2

6
Components

• Developed by CERN RD-26 in ALICE framework
  headed by F.
  Piuz, E. Nappi
• ALICE RICH Prototype Module (1.2 m2)

• Radiator
• C6F14 Liquid
• Photo Converter
• CsI
• l lt 210 (nm)
• Ionization Detector
• MWPC pad chamber
• CH4 Gas

80 mm
7
STAR-RICH PicturesBari/Cern/Yale STAR-RICH
Collaboration

• RICH at CERN Testbeam Setup in 98

• RICH at BNL Installation into STAR Magnet in 99

8
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

9
Mechanical Design Completed in 99

• RICH
• Safety Box with Nitrogen Flow
• 5 oclock West
• Width 7 Rails
• Cables/Tubes in Trays

10
Mechanical Design

• Safety Box
• Gas Flow with Nitrogen
• Front Panel
• Back Panel
• Thermal Shield
• Kinematic Mount

11
Gas System

• Relative Pressures Regulated by Bubblers
• Chamber
• 2.3 mbar CH4
• 3.1 mbar Ar
• Safety Box
• 1.8 mbar

12
Gas Requirements and Shipment
talk to F. Piuz to hear the fun details

• 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
13
Liquid System

• CsI Photo-Converter
• Vacuum Ultra-Violet (VUV) g
• Liquid Radiator
• 100L of C6F14
• Closed Recirculation/Cleaning
• VUV Transparency Monitor

14
Liquid System II

• Inert Liquid
• Fluoro Inert PF5060DL
• Closed Recirculation System
• Gravity Feed to/from Distribution Rack
• SS Pipes
• 3 Overpressure Relief Valves

15
Slow Control

• EPICS
• Temperatures
• HV-System
• LV-System

• Gas System
• Alan Bradley PLC
• Interlock
• EPICS Control
• Liquid System
• Siemens PLC
• VME-Scalers

16
Electronics

• GASSIPLEX CMOS 1.5 mm 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 gt 100 W/16k channels
• concern for liquid dn/dT 5x10-4 oC-1

17
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

18
Radiator

• Liquid C6F14
• Index of Refraction ?1.29
• pth 1.26 mc (GeV/c)
• Match Spectral Sensitivity of CsI

p
K
?
p
?
Ring Radii Proximity Focussing Normally
Incident Tracks
19
Liquid Again

• Oxygen and
  Water

20
Clean Liquid !
21
How long it takes to get there ....
22
Determination of Cherenkov Angle

• Cern Test Beam Determination
• 350 GeV/c p -
• Normal Incidence

• Resolution
• 12.0 mrad single g
• 3.0 mrad ring average

23
Alignment in STAR

• Track Extrapolation
• s drift 2.7 mm
• s bend 3.1 mm
• Near Expected Resolution
• 8.0 x 8.4 mm2 pads
• 4 mm anode wire pitch
• 2 mm anode-cathode spacing

24
The STAR Environment

• Effect of
• Track Incidence Angle
• Proximity Focussing

• Ring Azimuth Angles
• 180o
• 90o
• 60o

Normal Incidence
10o Incidence
20o Incidence
25
Golden Event

• Illustrative Example
• Separation Possible
• Signal/Background is Large
• Proximity Focussing produces Rings
• Both Pion and Kaon Emerge
• Size of MIP and g

26
Event Characteristics
Pixel Occupancy lt5
more central
Peripheral
Central
27
Separation Achieved !
28
Number of Photons in Real Analysis
Average Number is limited due to Incident Angle
Range
29
pbar/p Ratio in STAR
pbar/p ratio
30
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 !

31
STAR Collaborators/Institutions
400
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. Labs Argonne, Berkeley,
and Brookhaven National Laboratories

• U.S. Universities
• Arkansas, UC Berkeley, UC Davis,
  UCLA,
• Carnegie Mellon, Creighton, Indiana, Kent
• State, MSU, CCNY, Ohio State, Penn
  State,
• Purdue, Rice, Texas AM, UT Austin,
• Washington, Wayne State, Yale

32
STAR-RICH Collaboration
Y.Andres1, A.Braem1, M.Calderon2, N.Colonna3, D.
Cozza3 , M.Davenport1, L. DellOlio3, 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 CERN HMPID Group Yale Relativistic Heavy
Ion Group Bari HMPID Group Yale High
Energy Group
My Personal Special Thanks to F. Piuz
!!!!!!!!!!!!