Status of the Phobos

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Status of the Phobos experiment at RHIC
http//phobos-srv.lns.mit.edu
S.Manly Univ. of Rochester (http//maxwell.nsrl.ro
chester.edu/smanly/) for the Phobos
Collaboration APS - Atlanta March 23, 1999
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Phobos Collaboration
ARGONNE NATIONAL LABORATORY Birger Back, Alan
Wuosmaa BROOKHAVEN NATIONAL LABORATORY Mark
Baker, Donald Barton, Alan Carroll, Stephen
Gushue, George Heinzelman, Louis Remsberg, Andrei
Sukhanov CASE-WESTERN RESERVE UNIVERSITYCyrus
Taylor INSTITUTE OF NUCLEAR PHYSICS,
KRAKOWWojciech Bogucki , Andrzej Budzanowski,
Tomir Coghen, Kazimierz Galuszka, Jan Godlewski
,Roman Holynski, Jerzy Kotula, Marian Lemler,
Jerzy Michalowski, Andrzej Olszewski, Pawel
Sawicki Marek Stodulski, Adam Trzupek, Barbara
Wosiek, Krzysztof Wozniak, Pawel
Zychowski JAGELLONIAN UNIVERSITY, KRAKOWAndrzej
Bialas, Wieslaw Czyz, Kacper Zalewski MASSACHUSETT
S INSTITUTE OF TECHNOLOGYWit Busza, Patrick
Decowski, Kristjan Gulbrandsen, P. Haridas, Piotr
Kulinich, Heinz Pernegger, Miro Plesko, Gunther
Roland, Leslie Rosenberg, Pradeep Sarin, Stephen
Steadman, George Stephans, Gerrit van
Nieuwenhuizen, Carla Vale, Robin Verdier, Bernard
Wadsworth, Bolek Wyslouch NATIONAL CENTRAL
UNIVERSITY, TAIWANYuan-Hann Chang, Augustine
Chen, Willis Lin UNIVERSITY OF ROCHESTERAdam
Hayes, Erik Johnson, Steven Manly, Robert Pak,
Inkyu Park, Frank Wolfs UNIVERSITY OF ILLINOIS AT
CHICAGORussell Betts, Clive Halliwell, Burt
Holzman, Judith Katzy, Wojtek Kucewicz, Don
McLeod, Rachid Nouicer, Michael Reuter UNIVERSITY
OF MARYLANDEdmundo Garcia-Solis, Peter Stanskas,
Alice Mignerey
SpokespersonAt Goethe University,
FrankfurtProject Manager
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spectrometer
Two detectors

• ?4p detector
• measuring charged particle
• multiplicity and d N/dhdf
• multiparticle spectrometer
• covers 1 solid angle
• at midrapidity with
• low Pt threshold and good
• particle identification

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time of flight
multiplicity detectors
magnet
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Primary detector technology
Silicon detector schema
Silicon strips and pads 300 microns
bias bus
signal lines
metal 2
Dielectric 2
vias
metal 1
Dielectric 1
p Implant
Polysilicon Drain Resistor
n

HV
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Multiplicity array
h lt 5.3
-3.1 lthlt 3.1
-5.3 lt h
z
-1.13 m
1.13 m
2.34 m
-0.55 m
-5.04 m
-2.34 m
0.55 m
5.04 m

• 85 of 4p covered
• Charged part. multiplicity d2N/dhdj (j is
  azimuthal angle to beam) Dh 0.1 and Dj p/4
• Distinguish multiple hits by the energy
  deposition

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Multiplicity determination (event-by-event)
h
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The vertex detector
-12.5 cm
12.5 cm
11 cm
5.5 cm
x
Beam
Vertex detector
z
Octagon multiplicity detector
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Two-arm multiparticle Spectrometer
100 MeV/c
1 GeV/c

• 2 Tesla conventional magnet
• low field region helps with
• pattern recognition
• Particle ID via dE/dx

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Spectrometer performance
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• Pt spectra
• correlations
• phi mass, width
• particle ratios

Spectrometer physics
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Counting house
Facilities
Cable trays
Holes thru berm for cables
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magnet
RHIC!!
Danfysik
AGS
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Phobos Sensor Production
Vertex and Multiplicity
NCU Taiwan Production Pre-Testing
DHL
MIT and UIC Testing
Spectrometer
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Silicon detector assembly and testing
Hughes 2470-V bonder
Inspection stations
Si detectors mounted on spectrometer
cooling/support frame
Gluing Station
Clean Rooms
Probe Stations
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Trigger Counters
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Time-of-flight system
Hamamatsu R5900-00-M4MOD 12 stage multi-anode
PMTs
BC-404 fast plastic from Bicron
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Si Bias
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Mercury RACEway System
PowerPC 750 32MB DRAM 1MB SRAM L2 Cache 32kB L1
Cache
MCH6
MCH6
MCH6
A
A
A
B
B
B
C
C
C
D
D
D
0
2
1
To Event Builderover Ethernet
ILK 8 Mercury Backplane ( 8 Slots - only 3 are
shown here)
Standard VME Backplane
FPDP
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Event Builder
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Test beams
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Root/C
Software
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Miscellaneous
One spectrometer arm for year-one running 20
silicon detectors (mostly multiplicity and
vertex), DAQ, trigger, and parts of TOF installed
for commissioning run this summer
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conclusions

• PHOBOS is becoming a reality
• Significant parts of PHOBOS will be installed for
• commissioning run.
• Expect to be ready for day-1 physics (except for
  a
• completed second arm)