Forward Proton Calorimetry at

1
Forward Proton Calorimetry at

• Corey Reed / MIT
• 2003 Fall Meeting of the Division of Nuclear
  PhysicsOctober 30, 2003

2
Collaboration (October 2003)
Birger Back, Mark Baker, Maarten Ballintijn,
Donald Barton, Russell Betts, Abigail Bickley,
Richard Bindel, Wit Busza (Spokesperson), Alan
Carroll, Zhengwei Chai, Patrick Decowski,
Edmundo García, Tomasz Gburek, Nigel George,
Kristjan Gulbrandsen, Stephen Gushue, Clive
Halliwell, Joshua Hamblen, Adam Harrington, Conor
Henderson, David Hofman, Richard Hollis, Roman
Holynski, Burt Holzman, Aneta Iordanova, Erik
Johnson, Jay Kane, Nazim Khan, Piotr Kulinich,
Chia Ming Kuo, Willis Lin, Steven Manly, Alice
Mignerey, Gerrit van Nieuwenhuizen, Rachid
Nouicer, Andrzej Olszewski, Robert Pak, Inkyu
Park, Heinz Pernegger, Corey Reed, Michael Ricci,
Christof Roland, Gunther Roland, Joe Sagerer,
Iouri Sedykh, Wojtek Skulski, Chadd Smith, Peter
Steinberg, George Stephans, Andrei Sukhanov,
Marguerite Belt Tonjes, Adam Trzupek, Carla
Vale, Siarhei Vaurynovich, Robin Verdier, Gábor
Veres, Edward Wenger, Frank Wolfs, Barbara
Wosiek, Krzysztof Wozniak, Alan Wuosmaa, Bolek
Wyslouch, Jinlong Zhang ARGONNE NATIONAL
LABORATORY BROOKHAVEN NATIONAL LABORATORY INSTITU
TE OF NUCLEAR PHYSICS, KRAKOW MASSACHUSETTS
INSTITUTE OF TECHNOLOGY NATIONAL CENTRAL
UNIVERSITY, TAIWAN UNIVERSITY OF ILLINOIS AT
CHICAGO UNIVERSITY OF MARYLAND UNIVERSITY OF
ROCHESTER
3
Phobos Detector 2003
d
mini-pCal
Au
Two new calorimetersinstalled.
pCal
4
Calorimeter Modules

• Built by E864 (AGS)NIM A406, 227 (1998)
• Lead-scintillator10 cm x 10 cm x 117 cm
• 47x47 fibers / module
• 2 detectors built
• Au exit side 8x11
• d exit side 2x2

117.0 cm
5
Performance

• AGS energy resolution0.38 / sqrt(E
  (GeV))(single module)
• For our 8x11 array,0.23 / sqrt(E (GeV))
• Tubes very stable overdAu run
• No evidence of saturation

Shower simulation(top view)
Energy (arbitrary units)
6
PCAL Assembly
Pile on many more layers and Ill be joining you
there.
7
Calibration
Cosmic Ray Event in PCAL

• Au-exit side PCAL
• Cosmic triggers installed
• Use cosmic rays to calibrate
• Gains vertically symmetric
• d-exit side PCAL
• Gains vertically symmetric
• Relative gains horizontally match Au-exit side
  detector

Row
Column
8
Signal
Spectators
Recoils
d
Participants
In nucleus rest frame. White circles show
neutrons.

• Measure recoiling and spectator protons
• Use Glauber calculation to get centrality

9
Signal

• Au ion
• 100 GeV/c spectator proton
• 50 GeV/c recoiling proton

Protons bent into calorimeter byRHIC accelerator
magnet
10
Centrality Measure

• Independent centrality measure
• Correlates well with multiplicity-based measure
• See centrality talks by Richard Hollis and Aneta
  Iordanova

11
PCAL as Crosscheck

• PCAL used as crosscheck in study of systematic
  errors
• With PCAL centrality, data shows same features
• See talk by Abigail Bickley tomorrow

Preliminary
12
Deuteron Side PCAL

• On deuteron exit side
• PCAL finds proton,ZDC finds nothing
• nAu interaction
• PCAL finds nothing,ZDC finds neutron
• pAu interaction
• Studies underway

13
Deuteron Side PCAL

• Does the selection make sense?
• Signal in d-side PCAL
• Peripheral event

14
Summary

• New calorimeters added to Phobos
• Detectors working and stable
• Provide centrality information
• Provide information on collision system