Hadron Physics in China & 12 GeV JLab, Lanzhou, July 31, 2009 1 Zebo Tang, USTC Zebo Tang University of Science and Technology of China (USTC) MRPC-TOF

Hadron Physics in China & 12 GeV JLab, Lanzhou, July 31, 2009

1Zebo Tang, USTC

Zebo TangUniversity of Science and Technology of China (USTC)

MRPC-TOF R&D, calibration, performance

and related physics at STAR


2Zebo Tang, USTC

Outline

Introduction STAR MRPC-TOF R&D Calibration Performance PID and physics results achieved Summary & Outlook


3Zebo Tang, USTC

STAR Detector

MagnetMagnet

CoilsCoils

Central Central TriggerTriggerBarrel Barrel (CTB)(CTB)

ZCalZCal

Time Time Projection Projection

ChamberChamber(TPC)(TPC)

Year 2000Year 2000

Barrel EM Cal Barrel EM Cal (BEMC)(BEMC)

Silicon Vertex Silicon Vertex Tracker (SVT)Tracker (SVT)Silicon Strip Silicon Strip Detector (SSD)Detector (SSD)

FTPCFTPCEndcap EM CalEndcap EM CalFPDFPD

TOFp, TOFrTOFp, TOFr

PMDPMD

Year 2001+Year 2001+

Large acceptance: 2 coverage at mid-rapidity


4Zebo Tang, USTC

GeV/cm

Why do we need a TOF?

Specific Energy Loss in STAR TPCSpecific Energy Loss in STAR TPC

With the STAR TPC

K identification: p ~ 0.7 GeV/c

Proton identification: p ~ 1.1 GeV/c

S/N for reconstruction: ~ 1/few 100

Multi-strange particles reconstruction efficiency: ~ 10-4 --10-3

e

K

p

200 GeV Au+AuResolution ~8%


5Zebo Tang, USTC

TOF PID Capability

R. Majka for STAR

(~220 cm from the Beam Line)


6Zebo Tang, USTC

What can TOF do at STAR?

TOF

E-by-E

EvolutionDynamics

ExoticParticle

Searches

ParticleCorrelations

Baryon Transport: net baryons

Dynamical Fluctuations: /K/p Separation

Characteristic length: balance function, strangeness correlation

Particle CompositionBulk Property: CGC?

Elliptic Flow:/K/p////

Heavy Quark:

D,J/ Resonance:K*,

(1520),(1385),(1530)

Nucleosynthesis: 3He/t

Di-baryon: H or

- -p]

HBT: , KK

Unlike Particles: K, p and Kp.

Jet Fragmentation: Baryon-meson PID

Gluon Dynamics: K/, p/

Huan Huang


7Zebo Tang, USTC

Requirements

1) Good Time resolution The total resolution after all corrections must be <100 ps, for a start time resolution of 50 ps, 30 ps contribution from ∼ slew correction, pure stop resolution of less than 80 ps.∼

2) High Granularity （ dN/dy~1000 in central Au+Au) The detector segmentation must be such that the occupancy per channel is < 10%.

3) The system must be able to operate at particle fluxes up to 200 Hz/cm∼ 2.

4) The system must be able to operate inside the STAR magnetic field.

5) The system must fit into the integration envelope for the present CTB .

6) The system must be inexpensive


8Zebo Tang, USTC

The Multi-Gap Resistive Plate Chamber

E. Gorini et al. Nucl. Instr. Meth. A 396(1997), 93

Uniform High Electric Field ~11kV/mm high drift velocity ~220m/ns high Townsend coefficient.

Operate in Avalanche mode Gas: Freon (electron affinity ) iso-butane (UV photon absorption) SF6 (streamer suppressing) Heavy gas: 9-10 clusters/mm for MIP

Small gap: 0.2-0.3 mm, high resolution

Multi-gaps: high efficiency

MRPC is a good choiceFirst suggested by C. Williams et al for ALICE TOF


9Zebo Tang, USTC

MRPC R&D

a) Single pad MRPC 4×4 cm2 5×0.22mm gas gap

b) 12-pads MRPC 7×20cm2

6×0.25mm gas gaps pad size: 3.1×3 cm2

c) 6-pads 7×21cm2

10×0.25mm gas gaps pad size: 6×3.1cm2


10Zebo Tang, USTC

Beam Test Results

Efficiency: Time resolution: >~95% (6 gaps) ~70ps (5 gaps)

~99% (2×5 gaps) ~60ps (6 gaps)

~50ps (2×5 gaps)

Counting rates range : < 500Hz/cm2 (with normal float

glass)

Cheng Li et al., NST, V13N1

Single pad, 5 gaps


11Zebo Tang, USTC

A prototype at STAR (2002+)

Covers 6 in azimuth and 1 in pseudo-rapidity,at radius ~ 2.2 m

1/120 of total coverage Module: 20×6 cmGap ： 6×0.22 mmPad ： 3.15cm×6.1cmGas ： 95% C2H2F4 +5% Iso-C4H10

24 out of 28 modules made in USTC, China


12Zebo Tang, USTC

Timing Resolution before Calibration

Resolution = 124 psCalibration is necessary


13Zebo Tang, USTC

Electronics (2005+)

Start Detector

TOF Tray

TDIG TDIG

TCPU

DIFFERENTIAL DATA AND CLOCK

TINO TINO

MRPC MRPC

COMMANDS

48 CHAN

48 CHAN

48 CHAN

TRAY CAN BUS

MULTIPLICITY

THUB

COPPER: DATA, SAMPLE CLOCK, RESET TRIGGER STROBE & DATA

TOP LEVEL CAN BUS

COPPER LINKS TO 29 TRAYS

RHIC CLOCK

SIU FIBER

CAN BUS TO 29 TRAYS

TCD

DAQ

48 CHAN

4

L0 Trigger

4

PMTs TPMT TDIS TCPU

Diff. Data & Clk

Local CANbus

Co

pp

er:

Da

ta,

Sa

mp

le C

lk,

Re

set

Trg

Str

ob

e &

Da

ta

Reset & ClockFrom other THUBs

Reset & ClockTo other THUBs

2 THUB per side, 4 total 1 TCPU per tray/pVPD, 122

total 1 TPMT/TDIS per pVPD, 2 total

8 TINO/TDIG per tray, 960 total

24 chn. per TINO/TDIG, 23040 total

Schambach Jo et al., Int. J. Mod. Phys. E 16 2496


14Zebo Tang, USTC

2.7

0.9

HPTDC INL Correction

Jing Liu

Integral Non-Linearity

Differential Non-Linearity


15Zebo Tang, USTC

Time-TOT Correlation

Leading-edge trigger, signal charge (ADC) is measured for correction

time

Amp.

T1 T2

Thre.

Q1

Q2


16Zebo Tang, USTC

Hit Position Correction

propagation speed ：~45ps/cm

Signal output

Scan area

beam


17Zebo Tang, USTC

Choose sample by limiting dE/dx and momentum range (or pre-calibrated TOF)

T0 correction, different cable length and signal transition time

TOFr TOT and Z position calibration, using charged pion sample.

Iteration several times (if needed)

TOFr Calibration procedure

• Try channel-by-channel first• Not enough statistics? Then

try module-by-module, or board-by-board


18Zebo Tang, USTC

2005 Cu+Cu, 62 GeV

2005 Cu+Cu, 200 GeV

2009 p+p, 500 GeV2008 p+p, 200 GeV

TOF Timing Resolution


19Zebo Tang, USTC

TOF Time Resolution Summary

Operation condition

Time Resolution (ps)VPD

(start time)

TOFr (overall)

TOFr (stop time)

Run III200GeV d+Au ~85 ~120 ~85200GeV p+p ~140 ~160 ~80

Run IV

62GeV (Au+Au) ~55 ~105 ~89

200GeV (Au+Au)

FF/RFF ~27 ~74 ~70

HF ~20 ~74 ~71

Run V200GeV Cu+Cu (TOT) ~ 50 ~92 ~7562GeV Cu+Cu (TOT) ~ 82 ~125 ~94

Run VIII200 GeV d+Au NA NA NA

200 GeV p+p (TOT) ~83 ~112 ~75

Run IX 500 GeV p+p (preliminary) ~85 ~115 ~78


20Zebo Tang, USTC

Hadron PID

TOF alone:

/k ~1.6 GeV/c, (,k)/p ~ 3.0 GeV/c

TPC alone:/k ~0.7 GeV/c,

(,k)/p ~1.1 GeV/c

STAR Collaboration, PLB 616 (2005) 8

e

πK

p

TPC

TOF


21Zebo Tang, USTC

Light hadron with TOF

TPC only

Au+Au

p+p STARPRL92,112301(2004)

With ONETOF Prototype

STAR, PLB 616, 8 (2005); PRL 97, 152301 (2006)


22Zebo Tang, USTC

Electron and muon ID

arXiv: 0805.0364STAR, PRL 94, 062301, (2005)

|1/β-1|<0.03

Electron: pT>0.2 GeV/cMuon: pT<0.25 GeV/c


23Zebo Tang, USTC

Heavy Flavor with TOF

e

D0K

arXiv: 0805.0364

Very helpful for open charm and hidden charm physics


24Zebo Tang, USTC

Light Nuclei with TOF

Haidong Liu (STAR Collaboration), JPG 34, S1087 (2006), QM2006


25Zebo Tang, USTC

Resonance with TOFAu+Au 200GeV

(1029) (1029)

*K (892) *K (892)

Enhanced by a factor of ~4

Enhanced by a factor of ~2

Only one TOF track

Yichun Xu et al., NIM A596, 186 (2008)


26Zebo Tang, USTC

New Type MRPC-TOF R&D

1) Long Strip MRPC-TOF

2) High Resolution MRPC-TOF


27Zebo Tang, USTC

Long-strip MRPC R&D95 cm

25

cm

Suitable for:

1) Muon Telescope Detector @ STAR

2) TOF wall @ CBM

Pad size of STAR TOFLMRPC

2.5 cm


28Zebo Tang, USTC

Beam Test Results

Efficiency Plateau

Time resolution Plateau

Yongjie Sun et al., NIM, A593, 307 (2008)

At E~100 kV/cm (HV=±6300 V): Efficiency ~98% Resolution <70 ps


29Zebo Tang, USTC

Beam Test Results

Signal propagation velocity:

~ 60ps/cm The time difference: (T) ~ 55ps Position resolution: ~ 1 cm

USTC module, HV=6300V, run30-33

Position calculated from timing on two ends

Yongjie Sun et al., NIM, A593, 307 (2008)


30Zebo Tang, USTC

High Resolution MRPC R&D

Cheng Li


31Zebo Tang, USTC

Beam Test Results of a 24-gaps MRPC

Shaohui An et al., NIM A594, 39-43 (2006)

~21 ps


32Zebo Tang, USTC

Summary and Outlook The Advantage of MRPC-TOF:

good timing resolution (<80 ps) high efficiency (>90%) cost effective for large area TOF system

A prototype of TOF in STAR works very well: Satisfied all of the requirements Very helpful for identifying hadrons, leptons, light nuclei and

resonances, achieved lots of important physics results.

75% has been installed in STAR, 100% in 2010

A strong team at USTC is formed R&D, mass production, software, calibration, physics analysis

We are keeping working on new MRPC-TOFs R&D Long strip MRPC High resolution MRPC


33Zebo Tang, USTC

Extra slides


34Zebo Tang, USTC

Start Detector -VPD

Collision Point

VPD PMTs

W.J. Llope

•All hits in the same event arrived at the same time•As reference for each other


35Zebo Tang, USTC

Expectation (ideal)

TOF calibration w/o start detector

nTTtofZcorTOTcorTDCTn

i iiiii

10__

Fast simulation

Single channel resolution: 90ps

Time-TOT/Z correlation taken from real data

T0 obtained by direct average of Ti

6 iteration of calibration


36Zebo Tang, USTC

T0 resolution w/o start detector – from data

expected) (as ps74~0

2ps74~0

T

nTTi

60ps) :(expected ps63~0

3ps89~0

T

nTTi

n

i i

n

i iiii tofZcorTOTcorTDCT1

2

1

2 __0

Run V 62.4 GeV CuCu

After 6-round calibration iteration


37Zebo Tang, USTC

Time-TOT Correlation

Leading-edge timing signal, trailing-edge signal width (TOT)

time

Amp.

T1l T2l T2t T1t

Thre.

Time stamp

Leading-edge trigger, signal charge (ADC) is measured for correction

time

Amp.

T1 T2

Thre.

Q1

Q2

Documents

Hadron Physics in China & 12 GeV JLab, Lanzhou, July 31, 2009 1 Zebo Tang, USTC Zebo Tang University of Science and Technology of China (USTC) MRPC-TOF