# Presentation: 675655

## Forward Proton Calorimetry at

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

##                     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 Hołyński, 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 Woźniak, Alan Wuosmaa, Bolek Wysłouch, Jinlong Zhang
- 	ARGONNE NATIONAL LABORATORY	BROOKHAVEN NATIONAL LABORATORY
- 	INSTITUTE OF NUCLEAR PHYSICS, KRAKOW	MASSACHUSETTS INSTITUTE OF TECHNOLOGY
- 	NATIONAL CENTRAL UNIVERSITY, TAIWAN	UNIVERSITY OF ILLINOIS AT CHICAGO
- 	UNIVERSITY OF MARYLAND	UNIVERSITY OF ROCHESTER

- Corey Reed / MIT

- 2003 Fall Meeting of the DNP

## Phobos Detector 2003

- mini-pCal

- pCal

- Two new calorimetersinstalled.

- d

- Au

- Corey Reed / MIT

- 2003 Fall Meeting of the DNP

## 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**

- Corey Reed / MIT

- 2003 Fall Meeting of the DNP

## Performance

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

**Energy (arbitrary units)**

**Shower simulation****(top view)**

- Corey Reed / MIT

- 2003 Fall Meeting of the DNP

## PCAL Assembly

- “Pile on many more layers and I’ll be joining you there.”

- Corey Reed / MIT

- 2003 Fall Meeting of the DNP

## Calibration

- 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

**Cosmic Ray Event in PCAL**

**Column**

**Row**

- Corey Reed / MIT

- 2003 Fall Meeting of the DNP

## Signal

- d

- In nucleus rest frame.
- White circles show neutrons.

- Participants

- Recoils

- Spectators

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

- Corey Reed / MIT

- 2003 Fall Meeting of the DNP

## Signal

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

- Protons bent into calorimeter byRHIC accelerator magnet

- Corey Reed / MIT

- 2003 Fall Meeting of the DNP

## Centrality Measure

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

- Corey Reed / MIT

- 2003 Fall Meeting of the DNP

## 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

- Corey Reed / MIT

- 2003 Fall Meeting of the DNP

## Deuteron Side PCAL

- On deuteron exit side:
- PCAL finds proton,ZDC finds nothing
- n+Au interaction
- PCAL finds nothing,ZDC finds neutron
- p+Au interaction
- Studies underway

- Corey Reed / MIT

- 2003 Fall Meeting of the DNP

## Deuteron Side PCAL

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

- Corey Reed / MIT

- 2003 Fall Meeting of the DNP

## Summary

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

- Corey Reed / MIT

- 2003 Fall Meeting of the DNP