Transcript No Slide Title

The STAR-RICH
Gerd J. Kunde, Yale
 Background
 Transition
 Performance
[email protected]
Pylos June 2002
 Measurements
 Summary
1
STAR Au+Au
Central
Collision at
200 GeV
[email protected]
TPC
RICH
Pylos June 2002
STAR-RICH
2
The STAR-RICH
The HMPID Prototype
• Device Characteristics
– construction
– components
• Heavy Ion Environment
• Particle Identification
[email protected]
Pylos June 2002
4
Device Characteristics
• Extend PID beyond TPC
TOF:
1 < p < 3 GeV/c p K
2 < p < 5 GeV/c p
• 160 x 85 cm2  1.2 m2
• Radial Distance of 2.4 m
• |y| < 0.2
[email protected]
Pylos June 2002
5
Components
• Developed by CERN RD-26 in ALICE framework headed by
F. Piuz, E. Nappi
• ALICE RICH Prototype Module (1.2 m2)
80 mm
[email protected]
• Radiator
– C6F14 Liquid
• Photo Converter
– CsI
– l < 210 (nm)
• Ionization Detector
– MWPC pad chamber
– CH4 Gas
Pylos June 2002
6
STAR-RICH Pictures
Bari/Cern/Yale STAR-RICH Collaboration
• RICH at CERN : Testbeam Setup
in ‘98
• RICH at BNL: Installation into
STAR Magnet in ‘99
[email protected]
Pylos June 2002
7
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
[email protected]
• Closed Liquid System
– Transfer of liquid
under nitrogen
• Construction of NEW LV
Distribution Boards
made with FR4
Pylos June 2002
8
Mechanical Design Completed in ‘99
• RICH
• Safety Box with
Nitrogen Flow
• 5 o’clock West
• Width: 7 Rails
• Cables/Tubes in
Trays
[email protected]
Pylos June 2002
9
Mechanical Design
• Safety Box
– Gas Flow with
Nitrogen
– Front Panel
– Back Panel
• Thermal Shield
– Kinematic Mount
[email protected]
Pylos June 2002
10
Gas System
• Relative Pressures
Regulated by Bubblers
• Chamber
– 2.3 mbar CH4
– 3.1 mbar Ar
• Safety Box
– 1.8 mbar
[email protected]
Pylos June 2002
11
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
[email protected]
Pylos June 2002
12
Liquid System
• CsI Photo-Converter
– Vacuum Ultra-Violet (VUV) g
• Liquid Radiator
– ~100L of C6F14
– Closed Recirculation/Cleaning
– VUV Transparency Monitor
[email protected]
Pylos June 2002
13
Liquid System II
• Inert Liquid
– Fluoro Inert PF5060DL
• Closed Recirculation
System
• Gravity Feed to/from
Distribution Rack
• SS Pipes
• 3 Overpressure Relief
Valves
[email protected]
Pylos June 2002
14
Slow Control
•
EPICS
– Temperatures
– HV-System
– LV-System
•
Gas System
– Alan Bradley PLC
– Interlock
– EPICS Control
•
Liquid System
– Siemens PLC
•
[email protected]
VME-Scalers
Pylos June 2002
15
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 => ~100 W/16k channels
• concern for liquid dn/dT = 5x10-4 oC-1
[email protected]
Pylos June 2002
16
Pad Chamber
•
•
•
2-D Cathode Pad Readout
Photo Electrons
– 500 nm CsI Layer on Pads
• 8.0 x 8.4 mm2
Charged Particles
• 15360k pads
Dynamic Range
– Single Electron
– MIP detection
– Chamber Stability
– Ambient Pressure :-)
CH4 Chamber Gas
– Quenching
– High Photo-Electron Emission Efficiency
[email protected]
Pylos June 2002
17
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
[email protected]
Pylos June 2002
18
Liquid Again
•
[email protected]
Oxygen
and
Pylos June 2002
Water
19
Clean Liquid !
[email protected]
Pylos June 2002
20
How long it takes to get there ....
[email protected]
Pylos June 2002
21
Determination of Cherenkov Angle
• Cern Test Beam Determination
– 350 GeV/c p – Normal Incidence
[email protected]
•
Resolution
–
–
Pylos June 2002
12.0 mrad single g
3.0 mrad ring average
22
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
[email protected]
Pylos June 2002
23
The STAR Environment
•
Cherenkov
Light is
Internally
Reflected at
an Angle of ~10o
Effect of:
– Track Incidence Angle
– Proximity Focussing
•
Normal Incidence
Ring Azimuth Angles
•
180o
•
90o
•
60o
10o Incidence
20o Incidence
[email protected]
Pylos June 2002
24
Golden Event
• Illustrative Example
• Separation Possible
– Signal/Background
is Large
– Proximity Focussing
produces “Rings”
• Both Pion and Kaon
Emerge
• Size of MIP and g
[email protected]
Pylos June 2002
25
Event Characteristics
more
central
Peripheral
[email protected]
Pixel
Occupancy
<5%
Central
Pylos June 2002
26
Separation Achieved !
[email protected]
Pylos June 2002
27
Number of Photons in Real Analysis
Average Number is limited due to Incident Angle Range
[email protected]
Pylos June 2002
28
pbar/p ratio
pbar/p Ratio in STAR
[email protected]
Pylos June 2002
29
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 !
[email protected]
Pylos June 2002
30
~400
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
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,
Russia:
MEPHI – Moscow, LPP/LHE JINR – Dubna,
IHEP - Protvinoh
[email protected]
U.S. Labs:
Purdue, Rice, Texas A&M, UT Austin,
Washington, Wayne State, Yale
Pylos June 2002
31
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
My Personal
Special Thanks to
F. Piuz !!!!!!!!!!!!
CERN HMPID Group
Yale Relativistic Heavy Ion Group
Bari HMPID Group
Yale High Energy Group
[email protected]
Pylos June 2002
32