star’s upgrades – a path to the future helen caines yale university rhic/ags users meeting may...

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

2


PMD

STAR’s coverage

3

Photon capability from none to 4


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

4

Ready for Run 9/10

5


DAQ 1000 - TPC FEE and DAQ upgrades

6

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


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

7


PID plays crucial roles at RHIC

8

200 GeV Au+Au STAR Preliminary


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

9


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

10


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

11

12

Proposal In, Construction Starting


Poor man’s open heavy flavor measurements

13

e

Electrons: EMC: pT>2 GeV/c

TOF+TPC: 0.2<pT<4

Muon: TOF+TPC: pT~=0.2

K:Combinatoric K

reconstruction


The Heavy Flavor Tracker

14

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


Flavor structure of the polarized proton sea

15

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


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

16


Current upgrade timeline

17

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

18


Ideas in Germination

19

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


Direct HBT

20

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).


The photon converter

21

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.


Improving STAR’s muon capabilities

22

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-


The Muon Trigger Detector concept

23

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)


Hadron Rejection and Muon Trigger

24

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


Performance in STAR

25

• 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)


Novel “Problems” just around the corner

26

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?


GEM alignment detector

27

• 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.


Online tracking for high pT charged hadron

28

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?


Seeds from EMC+TOF for Dilepton tracking

29

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!


Forward ToF detector

30

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


On the right path towards an upgraded future

31

star’s upgrades – a path to the future helen caines yale university rhic/ags users meeting may...

Documents

rhic upgradesoutline

ebisdoe investment

gevcdoe investment

kchinese investment

current tpc fee

fee smaller

b mesonsdoe investment

run9 tpc