Status of the Phobos experiment at RHIC S.Manly Univ. of Rochester ( for the Phobos Collaboration APS - Atlanta March 23,

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 UNIVERSITY Cyrus Taylor INSTITUTE OF NUCLEAR PHYSICS, KRAKOW Wojciech 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, KRAKOW Andrzej Bialas, Wieslaw Czyz, Kacper Zalewski MASSACHUSETTS INSTITUTE OF TECHNOLOGY Wit 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, TAIWAN Yuan-Hann Chang, Augustine Chen, Willis Lin UNIVERSITY OF ROCHESTER Adam Hayes, Erik Johnson, Steven Manly, Robert Pak, Inkyu Park, Frank Wolfs UNIVERSITY OF ILLINOIS AT CHICAGO Russell Betts, Clive Halliwell, Burt Holzman, Judith Katzy, Wojtek Kucewicz, Don McLeod, Rachid Nouicer, Michael Reuter UNIVERSITY OF MARYLAND Edmundo Garcia-Solis, Peter Stanskas, Alice Mignerey *Spokesperson †At Goethe University, Frankfurt ‡Project Manager Phobos Collaboration

  4  detector measuring charged particle multiplicity and d N/d  d  v multiparticle spectrometer covers 1% solid angle at midrapidity with low P t threshold and good particle identification time of flight multiplicity detectors spectrometer magnet Two detectors: 2

Silicon detector schema +HV p+ Implant n+ Polysilicon Drain Resistor Dielectric 1 bias bussignal lines Dielectric 2vias metal 1 metal 2 Primary detector technology Silicon strips and pads 300 microns

-0.55 m-5.04 m-2.34 m-1.13 m 0.55 m 1.13 m 2.34 m 5.04 m z      85% of 4  covered Charged part. multiplicity d 2 N/d  d  (  is azimuthal angle to beam)    and  Distinguish multiple hits by the energy deposition Multiplicity array

 Multiplicity determination (event-by-event)

Beam z 12.5 cm cm 11 cm 5.5 cm x The vertex detector Vertex detector Octagon multiplicity detector

Two-arm multiparticle Spectrometer 100 MeV/c 1 GeV/c 100 MeV/c ++  - adjustable separation -- v2 Tesla conventional magnet vlow field region helps with pattern recognition vParticle ID via dE/dx

Spectrometer performance

Spectrometer physics v Pt spectra v correlations v phi mass, width v particle ratios

Facilities Counting house Holes thru berm for cables Cable trays

magnet Danfysik AGS RHIC!!

Phobos Sensor Production NCU Taiwan: Production & Pre-Testing MIT and UIC: Testing Spectrometer Vertex and Multiplicity DHL

Silicon detector assembly and testing Clean Rooms Probe Stations Inspection stations Hughes 2470-V bonder Gluing Station Si detectors mounted on spectrometer cooling/support frame

Trigger Counters

Time-of-flight system BC-404 fast plastic from Bicron Hamamatsu R M4MOD 12 stage multi-anode PMTs

Si Bias

RIN-T (2 Slots) PowerPC 200 MHz 32 MB RAM PowerPC 200 MHz 32 MB RAM Mercury™ RACEway™ System A B C D ILK 8 Mercury Backplane ( 8 Slots - only 3 are shown here) Standard VME Backplane MVME 2604 PowerPC with VxWorks 200 MHz 32 MB RAM To Event Builder over Ethernet MCH6 A B C D ROU-T (2 Slots) PowerPC 200 MHz 32 MB RAM PowerPC 200 MHz 32 MB RAM MCH6 021 A B C D PowerPC 200 MHz 32 MB RAM PowerPC 200 MHz 32 MB RAM PowerPC MB DRAM 1MB SRAM L2 Cache 32kB L1 Cache FPDP

Event Builder

Test beams

Root/C++ Software

Miscellaneous Time-of-Flight Walls Ring Detectors Spectrometer Octagon and Vertex Detector Magnet 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

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)