# Presentation: 787288

** **

_**Status of the STAR**_

**J. Harris, BNL PAC - 23 March 2000**

## STAR Detector (year-by-year) 

**1****st**** year detectors (now)                 ****year-by-year implementation until 2003 **
**2****nd**** year detectors****                           ****installation in 2003**

**ZCal**

**Silicon Vertex Tracker *******

**Central Trigger Barrel**
**+ TOF patch**

**Barrel EM Calorimeter**

**Coils**

**TPC Endcap & MWPC**

**ZCal**

**RICH**

*** yr.1 SVT ladder**

## STAR Year 1 Detector Configuration

**Baseline Detector**
**Solenoid Magnet**
**TPC and Electronics**
**DAQ and Online**
**Trigger Detectors**
**Central Trigger Barrel**
**Multi-wire Chamber Readout**
**Zero Degree Calorimeter****	**
**RICH ~10 msr at y****c.m. **
**- 0.3 < ******** < 0.3, ******** = 20o****	**
**EMC ~ 4 % of eventual (******** = 2, ******** = 2********) coverage **
**0 < ******** < 1, ******** = 24o**
**FTPC - 1 of 2 to be installed in Spring 2000**
**2.5 < ******** < 4.0, ******** = 2******
**Level 3 Trigger**
**presently 1 ******** processor per two TPC sectors (x 2 by Summer)**

## STAR Detector Acceptances(1st Year)

_**STAR Detector Acceptances**_**(1st Year)**

** **

**FTPC**

**TPC**

**RICH**

**EMC**

**CTB Trigger**

**MWC**

**MWC**

**ZDC**

**ZDC**

## STAR Year 2 Detector Configuration(additions)

**Baseline Detector (Magnet, TPC, Trigger detectors, DAQ, Online)**
**RICH ~ 10 msr at y****c.m. **
**EMC****  increase to ****~ 30 %**** of eventual (-1 < |********| < 1, ******** = 2********) coverage **
**SVT -   -1 < |********| < 1, ******** = 2******
**FTPC #2  -  2.5 < |********| < 4.0, ******** = 2******
**TOF Patch -  0 < ******** < 1, ******** = 6o**
**Level 3 Trigger**
**2 ******** processors per two TPC sectors**

## STAR Detector Acceptances(2nd Year)

**FTPC**

_**STAR Detector Acceptances**_**(2nd Year)**

** **

**FTPC**

**TPC**

**RICH**

**EMC**

**TOF**

**SVT**

## Magnet - Status

**The Magnet has achieved full field operation**
**Full field (0.5 T) and half-field mapping completed**
**Field features were measured down to the 1-2 Gauss**

**K. Foley**
**S. Trentalange**

**Radius**

**Z Axis**

**B****R****  Measurements**

## TPC - Status

**The TPC is installed in STAR**
**139,000 channel electronics system installed and working**
**Operated in beam during summer 1999 RHIC engineering run**
**Cosmic ray running in Dec. 1999 and Feb.-Mar. ‘00**
**Cosmic Ray, Laser, and pedestal data is being analyzed, now.**
**Events and tracking results**

## Cosmic Ray Event - July 23rd, 1999.

**B field = 0.5 Tesla**

## Beam - Gas Event (Summer 1999)

**Clusters, Spacepoints, and tracks reconstructed with offline Software**

## Level 3 trigger  	 1-March-00 		B = .5 T

_**Level 3 trigger**_**  ****	**** 1-March-00 ****	****	****B = .5 T**

## March 2, 2000

**March 2, 2000**

**Reconstructed Laser Event in the TPC**

## From RHIC commissioning run

_**TPC Performance**_

_**Position resolution**_** ~ 800 mm, expect 500 mm**
**will improve with corrections and B field**
_**Momentum resolution**_** 80% larger than goal**
**will improve when use B field map**
_**dE/dx resolution**_** 11%, expect 7%**
**will improve with reduced threshold **
**& corrections**
_**Front-End electronic noise**_** ~1100 e- rms, on spec**
**Test with high multiplicity only in first collisions**

## December ‘99 Cosmic Ray Data - Preliminary

## DAQ - Status

**DAQ is completely installed and working**
**Entire TPC being read out; Other subsystems (RICH, SVT ladder) being integrated**
**Works beautifully- runs of 100k cosmic ray events taken with no problems**
**Data being fed to RCF over Gbit ethernet at required 20MB/s**

- Receiver Board

- Mezzanine Board (front and back views)

- DAQ Crate

- Receiver Board populated with 3 Mezzanine boards

## Trigger - Status 

**Trigger working well  for cosmic ray runs through Level-3**
**Level-3 will be fully implemented **
**	****~  1 year **

-  _**Central Trigger Barrel**_** **
**120 element hodoscope with electronics installed, tested & working**
** **_**End Cap TPC anode trigger**_** electronics installed & being debugged**
** **_**Z0 Calorimeters**_** working**

## Ring Imaging Cerenkov Counter

**PID for Kaon/Pion/Proton**
**1-3 GeV/c for K/pi**
**1.5-5 GeV/c for p/anti-p **
**Located at  y=0 in STAR**
**INSTALLED IN STAR**
**Rings have been seen from cosmic rays (early March)**
**------------------------------------**
**C****6****F****14**** Liquid Radiator**
** ****CsI Photo Cathode**
** ****MWPC with 16,000 Pads **
** ****Multiplexed Electronics**

## The Forward TPCs

_**The Forward TPCs**_

**2 chambers;  1 for each end; **
**Radial drift TPC**
**First chamber assembly almost complete**
**   ****with 30 readout chambers installed**
**HV testing in progress**
**FEE Board design complete**
**64 channels per board**
**Smaller package for SAS & SCA chips**
**FEE  boards to be added soon**
**Installation in fall 2000**

## STAR Physics Program

_**Relativistic Heavy Ion Physics**_
**High Density QCD Matter**
**QCD Deconfinement Phase Transition**
**Chiral Phase Transition**
_**Polarized Proton-Proton Interactions**_
**Spin Structure of the Nucleon**
_**2-Photon Physics**_** **
**Intense EM Fields of Passing Nuclei ***** ***
******Coherent Source of ********’s**
**Investigate the Plethora of Particles in 1 - 2 GeV Mass Range **
**	****(cannot be fit by QCD)**

## STAR RHI Physics Program

_**Initial Conditions**_
**Nuclear (q and g) structure functions, nuclear shadowing**
_**PQCD Probes**_
**Parton (jet, mini-jet, high Pt particle) propagation/attenuation in matter**
**High Pt spectra (gluon versus quark jet production)**
_**EM Probes**_
**Virtual photons (e+e-)**
_**Probes of Deconfinement**_
**J/P suppression (e+e-)**
**Flavor equilibrium (strangeness saturation, multiply-strange baryons)**
**Critical (non-statistical, dynamical) fluctuations**
_**Probes of Chiral Restoration**_
**Resonance widths, masses, and branching ratios**
**Isospin fluctuations, disoriented chiral condensates (charge to neutral ratios)**
_**Kinematic Probes**_
**Hadronic p.I.d. spectra (y, Pt) -  thermalization (T, ********B****, s, ********s****, ...) and freeze-out**
**HBT - space-time evolution (possible phase change)**
**E-by-E (Pt, HBT, collective flow, strangeness content - i.e. T, ********B****, s, ********s****, ...) **
**Anti-baryons, anti-nuclei **

## Beam Request differences between 4/99 and now

_**STAR RHIC BUR 4/99**_
**Initial phase of STAR operation dedicated to understanding performance of detector and trigger****.  ********  up to 4 weeks. **
**Then, survey of measurements starting with Au + Au at the top energy available.**
_**Now**_
**Past year - operation, testing and exercising TPC, electronics, DAQ,.... ****	**
**Engineering run - discovered several small problems**
**Some bad FEE cards, higher electronics noise ******** corrected**
**Remaining baseline DAQ and trigger systems delivered, installed, tested ******** **
** ****	****	****Now being exercised (shaken down) and optimized. **
**With these improvements and additional test time ******** **
**Firm understanding of detector, associated trigger and DAQ systems **
**STAR startup time from RHIC collisions to data acquisition for physics **
**	******** ****2 - 3 days.**

## Present Beam Request

**Data-taking goals for STAR with Au + Au at top energy available:**
** **
**   ****1,000,000 central trigger events **
**	****                ****(~ 5 % geometrical cross section)**
**    ****2,000,000 minimum bias events **
**	****     ****	****       ****(~ 95 % geometrical cross section)**
**2,000,000 two-photon events **
**	****(# charged particles < 6)**
****** ****8 weeks data acquisition at ******** 1 %  L****o**
**	****(assumes 25% overall efficiency, scales linearly with time)**
**No change of beam**

## A Feel for STAR Data Acquisition Rates for Various Triggers

_**Trigger**__**	**__**	**__**Event Size**__**	**__**rate (~1%L**__**o**__**)**__**	**__**~ Bandwidth**__**	**__**events in 4 wks**_
**	****	****	****	****	****	****	**** ****	****	****     ****(******** = 25%)**
**Central ****	****	****20 MS****	****	****~ 1 / s****	****	****90% ******** 18 MB/s****	****     0.5 M**
**(5% ******** ****geo****)**
**Min. Bias****	****1 MB****	****	****~ 20 / s****	****	****10% ******** 2 MB/s****	****     1.0 M**
**(95% ******** ****geo****)**
******(********P,PP)****	****0.2 MB****	****	****~ 2 / s****	****	**** 5% ******** 1 MB/s****	****     1.0 M**

## Overview of STAR Physics in the 1st Year

**As listed in Table 3 of STAR BUR 4/99 :**
**charged hadron spectra (yields, Pt slopes)**
**charged hadron spectra at high Pt **
**	****	****(~ 3% statistical error in 1 GeV/c bin at 9 GeV/c)**
**the********, K****o**** yields & slopes**
**light anti-nuclear and nuclear fragment yields & slopes**
**identified particle spectra in the RICH for ******** and K to 3 GeV/c**
**particle correlations (including Pt binning of results)**
**event-by-event physics (flow, correlations, fluctuations, dimensional analysis)**
**Physics goals negatively affected by shortened run (rel. to BUR 4/99):**
**identified particle spectra in the RICH for protons and anti-protons to 5 GeV/c**
**Pt and rapidity binning of various observables (esp. HBT & E-by-E)**
**no reference data with Si + Si nor p + p**

## High pt Particle Spectra and High pt Correlations

_**High p**__**t**__** Particle Spectra and High p**__**t**__** Correlations**_

_**Event Requirements**_** (for 1000 counts per GeV/c bin)**
**negative hadrons**
** ****p****t**** = 5 GeV/c**
**req. ****1 x 10****4**** (central)**** ********4 x 10****4 ****(min bias)**** ****events/sample**
**p****t**** = 8 GeV/c**
**req. ****2 x 10****5**** (central)**** ********8 x 10****5 ****(min bias)**** ****events/sample**
** ********+-****, K****+-**
**p****t**** = 3 GeV/c (in RICH)**
**req. ****2 x 10****5**** (central)**** ********8 x 10****5 ****(min bias)**** ****events/sample**
**p****+-**
**p****t**** = 5 GeV/c (in RICH)**
**req. ****5 x 10****6**** (central)**** ********2 x 10****7 ****(min bias)**** ****events/sample**
** ********o**
**p****t**** = 5 GeV/c (in EMC patch)**
**req. ****2 x 10****5**** (central)**** ********8 x 10****5 ****(min bias)**** ****events/sample**

**X.N. Wang, nuc-th/9711026**

## Event-by-Event and Multi-Particle Correlations

**Event-by-Event Studies**
**1% event class  analysis          (req. ****10****6**** (central)**** evts/sample)**
**[e.g. strangeness yields, other yields, flow, <p****t****>********, K, p ****, HBT (R****inv****)]**
**Multi-particle Correlations (centrality trigger)**
**HBT ****	****	****	****(********++****, ********--****, ********+- ****background)**
**3-D analysis****	****	****req. ****≤ 10****5**** (central)**** ********≤ 10****6 ****(min bias)**** ****events/sample**
**p****t****, y binned analysis****	****req. ****≤ 10****6**** (central)**** ****events/sample**
**Photon/Pomeron Physics (N****ch**** < 6 trigger)**
**Particle Correlations for ********, ********g, and Pomeron Physics**
** ********e****+****e****-****, ********+********-****, f****2**** (1270)****	****~ 33K f****2****(1270) in first year**
** ********mesons, ********************	****	****~ 600 ******************** events in first year**
** ********P********~ few million 2-particle events**
**search for glue-balls f****J****(1710), ********(2230)****	****?**

## Evolution of STAR during this Year’s Run

**Installation of EMC barrel module electronics **
**	****	****	****will lead to some EMC data-acquisition**
**Possible addition of one FTPC during PHOBOS-requested shutdown**

## Projection for Next Year's Running

**Au + Au beam at top energy**
**	****	****(possibly at lower energy)**
**Si + Si and p + p at top energy **
**	****	****(possibly at lower energy)**
**Polarized p + p**
**Possible other beam/energy changes, **
**	****	****depending upon what we see in this year’s data**

## Overview of STAR Physics in the 2nd Year

**Additional physics beyond Year 1**
**charged hadrons at low Pt (with SVT)**
**multiply-strange baryon (******** yields & slopes (with SVT)**
**increased statistics for strange particles (with increase in efficiency of SVT)**
** ********o**** identification, yields, slopes(with EMC)**
**high Pt triggering (with EMC)**
**transverse energy measurements (with EMC)**
**measurements of charged hadrons and strange particles at forward rapidities**
**	****	****(with FTPCs)**
**increased coverage for event-by-event physics **
**	****	****(flow, correlations, fluctuations, dimensional analysis)**
**Start modest polarized proton program**
**transverse analyzing power (A****T****)**
**	****requires ~ pb****-1**** transversely polarized protons**
**	****polarimetry at RHIC (possibly STAR)**
**inclusive jets ********* *****A****LL**** which is sensitive to ********G(x)**
**	****requires spin rotators at STAR & jet triggering**

## STAR is Ready for Physics at RHIC

## Silicon Vertex Tracker

**SVT IS A 3 LAYER VERTEX    DETECTOR WITH 216 ELEMENTS****	**
**Each element is a solid state TPC **
**3-D space points with ~20 micron resolution**
**Dec. 99--Single ladder with 7 elements installed in STAR; 3 elements coupled to readout**
**Cosmic ray data being analyzed**
**Laser generated data shows response as expected**
**FULL SVT IN BEAM LATER IN YEAR**
**Silicon Strip Detector (SSD) gives 4th layer between SVT and TPC; will be installed with SVT**

## Barrel EMC - an AEE project

** ****Full Size prototype module and Shower Max detector (SMD) successfully tested in AGS Test Beam**
** ****Module and SMD production ongoing; 14 modules and 24 SMD complete**
** ****4 modules with SMD installed in STAR; will have prototype electronics for upcoming RHIC run**
** ****Production and Installation of EMC modules will be phased over the next three years.**

## End Cap EM Calorimeter

_**End Cap EM Calorimeter**_

**Lead/scintillator projective towers; with shower max**
**Funded by NSF, Indiana Univ.; IUCL; DOE**
**Design almost complete**
**Successful test of prototype in SLAC beam in Oct. 99**
**Actual construction about to begin**
**Goal: install in summer 2002**

## Summary

**Successful STAR engineering run in Summer ’99 with operation of most of baseline detector**
**some problems found, debugged & corrected**
**Completion of DAQ and Trigger & extensive testing of all systems with cosmic rays since then **
**STAR is ready for beam and physics**
**With Baseline, RICH, 4 EMC modules, SVT ladder**
**Full STAR capability attained with ****additions of SVT, FTPCs, TOF Patch, Level 3 Trigger, SSD, EMC Barrel and End Cap**** implemented during next 2-3 years**