star’s upgrades – a path to the future helen caines yale university rhic/ags users meeting may...
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STAR’s Upgrades – A Path to the Future
Helen CainesYale University
RHIC/AGS Users MeetingMay 2008
Workshop on RHIC Upgrades
Outline:Just UsedInstalled for Run 9Under ConstructionContemplating
Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008
STAR’s detector upgrades
MRPC ToF barrelMRPC ToF barrel
Ready for run 10Ready for run 10
RPSD
PMD
FPD
FMS
EMC barrelEMC End Cap
DAQ1000DAQ1000
Ready for run 9
HFT; FGT: GEM-layers
finished
ongoing
MTD
R&D
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Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008
PMD
STAR’s coverage
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Photon capability from none to 4
Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008
Aim to keep the discoveries rolling …
DAQ1000 Upgrade order of magnitude increase in rate (1KHz) extra livetime opens the door to rare physics
Full Barrel MRPC TOF extended hadron identification at intermediate pT
Lepton identification at low momentum
Heavy Flavor Tracker High precision Silicon tracker near the primary vertex Opens door to direct topological charm and beauty reconstruction
Forward GEM Tracker End cap tracker for particle sign determination for W
Muon Telescope (BNL LDRD) Forward Reaction Plane Detector A Crystal Calorimeter for low E photons Pb converter for - HBT GEM alignment detector
Un
der
way
R&
D/P
rop
osal
sM
ore
idea
s
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Ready for Run 9/10
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Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008
DAQ 1000 - TPC FEE and DAQ upgrades
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Faster, smaller, better … ( 10x )
Current TPC FEE and DAQ limited to 100 Hz. Replace TPC FEE with next generation CERN based chips … 1 kHz readout
Zero suppression done at FEE. 16-20x smaller
Make the FEE smaller. less heat
Almost no deadtime –rare physics program
By only archiving “associated” clusters – build on L3 algorithms … 5 kHz !
Prototype in run 7, 1 sector in run8, Full system in run9
TPC is now a fast detector!!!
blue pen
PASAsALTROs
brown rulerFPGAs
Fiber Out via SIU
FEE In
Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008
1/17/2008 Laser event (plus pileup)
Data from DAQ1000 sector Data from DAQ1000 sector look goodlook good
TPX dE/dx from TOF+TPX events
DAQ1K at 1000Hz, 5—7% deadtime
Commissioning in run 8
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Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008
PID plays crucial roles at RHIC
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200 GeV Au+Au STAR Preliminary
Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008
Multi-gap Resistive Plate Chamber Time-of-Flight
State-of-art MRPC: -0.9<<0.9, 0<<2, r=220cm 6 gaps, 3x6cm2 pad;
23K channels, 120 modules
Most significant collab. to date between USA & China in HEP detector research
1 tray in runs 2-75 trays in run 8
~75% in run 9100% in run 10
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Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008
Improving the “Time” in Time-of-Flight
Run8: 76M pp events TOF+TPX
• 2001: No timing devices (except Time Projection Chamber)• 2002: BBC (~1ns), ZDC (200ps)• 2002-2008: TOF tray+VPD (<100ps)
• 2008-:
finally TOF t: 81ps
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Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008
Physics with the full TOF Hadron and lepton PID at mid-rapidity – (Energy scan)
Identified p/ at high pT
Jet-related PID spectra & correlations
Fluctuation K/, p/ – (Critical point)
Resonances (,,J/) hadronic and dilepton decay channels
Open Charm (daughter PID)Leadinghadrons
Medium
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Proposal In, Construction Starting
Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008
Poor man’s open heavy flavor measurements
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e
Electrons: EMC: pT>2 GeV/c
TOF+TPC: 0.2<pT<4
Muon: TOF+TPC: pT~=0.2
K:Combinatoric K
reconstruction
Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008
The Heavy Flavor Tracker
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Thin 50 m Si pixels reduce limitations imposed by MCS and
give 10 m space point resolution See Flemming’s talk later
Direct Topological reconstruction of Charm
Detect charm decays with small c, i.e. D0 K
New physics Charm collectivity and
flow to test thermalization at RHIC
Charm Energy Loss to test pQCD in a hot and dense
Aiming for CD1 in Fall
Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008
Flavor structure of the polarized proton sea
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Probe at RHIC via parity violating W± production and decay.
)(W
d u W
d u W
W e eW e e
Experimental signature: high pT lepton from W decay:
For √s=500 GeV p+p collisions. The quark is usually a valence quark large x
Polarized PDFs only weakly constrained by fixed target data
Flavor separation possible via identification of W’s charge
Need forward tracking
Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008
Forward GEM Tracker (FGT)
6 triple-GEM disks covering 1 < < 2
outer radius ~ 40 cm
inner radius varies with z position
W charge sign reconstruction prob. >80% for 30 GeV pT over full EEMC acceptance
and vertex spread ( >90% out to η= 1.8)
Probability to get the correct charge sign
See Bernd’s talk later
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Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008
Current upgrade timeline
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Run08 Run10Run09 Run12Run11 Run13 Run15Run14
FMS complete:d+Au and p+pdata from Run 8
DAQ1000 completeImmediate improvementof 300% in sampled luminosity for rare probes(e.g. jets in p+p)
Increase in Au+Au luminosity to50 x 1027 cm-2 sec-1
U+U available from EBISDOE investment ~ $7M
HFT partial implementation
HFT completefull topological PID forc, b mesonsDOE investment : upperlimit of range ~ $14.7M
Planned LHC1st heavy ion run
DOE investment ~ $400k
DOE investment ~ $1900k
TOF complete:
PID information for > 95% of kaons
and protons in the STAR acceptance
Clean e± ID down to 0.2 GeV/c
DOE investment ~ $4900kChinese investment ~ $2700k
FGT complete:Accurate charge sign determinationfor W’s, DOE investment ~ $1900k
Ideas in germination
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Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008
Ideas in Germination
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Photon converter HBT for direct photons
Muon Telescope DetectorJ/ trigger
GEM CalibrationHigh pT resolution
Reaction Plane DetectorImproved resolution for v2 measurements
Online trigger trackingTriggering and data reduction
Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008
Direct HBT
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Direct s: Produced in all stages of collision. Emitted without re-scattering Directly sensitive to T evolution Swamped by 0 decay bkgrd.
Simulation: Simulation: Central Au-Au Central Au-Au
Analysis challengingAnalysis challenging
However HBT correlations only exist between direct photons. Correlation peak gives direct photon yield down to low pT
Importantly, HBT gives information on temperature vs. size development through all stages of collision!
Simulations show that a real Simulations show that a real measurement is possible in measurement is possible in STAR with minimum addition STAR with minimum addition (converter). (converter).
Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008
The photon converter
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10% radiation length Pb photon converter at R~43 cm (inside TPC)
Converter retractable so that for most of the run it would not interfere with tracking in ||<1 region.
Analysis effic. improved, especially at low relative momentum. Reconstruct one via converter and other in BEMC
Run with DAQ1000 to measure HBT at low pT.
Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008
Improving STAR’s muon capabilities
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Simulations
Install a large area mid-rapidity muon telescope. Allows detection of:
Di-muon pairs:Quarkonia, QGP thermal radiation,Drell-Yan
Single muons : Heavy flavor semi-leptonic decays
Advantage over e:No conversion, Less Dalitz decay, Less radiative losses to detector material
+-
e+e-
Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008
The Muon Trigger Detector concept
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Prototype Installed in RUN 7-8
Long MRPC Technology with double-end readout
20x larger than ToF modulesHV: 6.3 KV,
gas: 95% Freon + 5% Isobutane
10 gas gaps: 250 m
time resolution: ~60 ps
spatial resolution: ~1cm
Place scintillators outside magnet covering iron bars
Muon efficiency: 35-45%Pion efficiency: 0.5-1% Muon-to-Hadron Enhancement Factor: 100-1000 (including track matching, ToF, dE/dx)
Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008
Hadron Rejection and Muon Trigger
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Iron bars
•Muon penetrates iron bars Other particles are stopped
•Good Time Resolution (60ps) rejects background (>100)
•1 hit per 5 head-on Au+Au Dimuon trigger (>25)
•Large coverage: diameter of 7 meters
A BNL 2007 LDRD project
J/ trigger, separate +- states
Full Hijing AuAu event
Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008
Performance in STAR
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• z distribution of matched MTD hits has two components: narrow () and broad (hadron) ones
from data: pT>2 GeV/c, (z) of muon: ~10 cm from simu: pT=2.5 GeV/c, (z) of muon: ~9 cm
• hadron rejection: 200-300 (via track matching)• time resolution: 300 ps Improve our electronics for full scale detector
pT > 2 GeV/c STAR Preliminary
p T (
GeV
/c)
z (cm)
Simulations
Data
z (cm)
p T (
GeV
/c)
Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008
Novel “Problems” just around the corner
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Can we understand the distortion at high luminosity and maintain the momentum resolution?
Can we analyze all the data from DAQ1000 effectively?
Can we improve our reaction plane, especially at low energies?
Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008
GEM alignment detector
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• As luminosity increases the TPC As luminosity increases the TPC distortions due to residual charge in distortions due to residual charge in chamber increase.chamber increase.
Resolution Resolution
Focus on high pFocus on high pT T
• VitalVital that we can correct for these that we can correct for these distortions on distortions on track-by-track track-by-track basis basis
• Capitalize on GEM technology and Capitalize on GEM technology and readout developed for FGT and place a few readout developed for FGT and place a few detectors outside of TPC radius detectors outside of TPC radius
• Measure precise points (~100 Measure precise points (~100 m) on m) on tracks at outer radius of TPC in strategic tracks at outer radius of TPC in strategic locations to provide a strong constraint on locations to provide a strong constraint on the space charge distortion corrections. the space charge distortion corrections.
Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008
Online tracking for high pT charged hadron
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DAQ1000, 12 weeks, 50% data-time, 1000Hz: 3.63 billion events, how to handle????
Central 0-5%: pT>4 GeV/c, (h++h-) raw yield: 6.52e-02 per event, 236M evts pT>5 GeV/c, (h++h-) raw yield: 1.37e-02 per event, 50M evts pT>6 GeV/c, (h++h-) raw yield: 4.15e-03 per event, 15M evts
p+p: pT>4 GeV/c, (h++h-) raw yield: 3.10e-04 per event, 1.13M evts pT>5 GeV/c, (h++h-) raw yield: 6.52e-05 per event, 237K evts pT>6 GeV/c, (h++h-) raw yield: 1.97e-05 per event, 72K evts
Needs ~20% primary track momentum resolution at 5 GeV/cEMC and GEM Patches for calibration online?
Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008
Seeds from EMC+TOF for Dilepton tracking
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Dielectron and background rates for TPC+TOF+EMC+Online
Events needed could be reduced from ~1billion to <100 million
Using seeds from EMC+TOF reduces tracks from 1000s to a few
Pt (GeV/c) Electron per event
Rejection factor
>1.0 0.31 10
>1.5 0.06 278
>2.0 0.016 4000
EMC
EMC
At least 10% dE/dx resolution ~150ps TOF calibration
MTD could provide dimuon seeds
Both ideas need further exploration!
Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008
Forward ToF detector
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MRPC ToF rings at forward rapidity 2.75<|η|<3.75128 MRPC modules located at z = ±6.5m.
Granularity to provide good estimate of the reaction-plane even in U+U collisions.
PID forward, tracking from FTPC’s v1 and particle ratios
Start-time signal for barrel ToF for low E scan (current VPD may not fire due to small acceptance and low mult. VPD covers only 55% of area in range 4.4<η<4.9)
Good background rejection during low E scan
Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008
On the right path towards an upgraded future
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