Long-strip MRPC for CBM

Long-strip MRPC for CBM

Yongjie SunKey Laboratory of Technologies of Particle Detection & Electronics, CAS

University of Science and Technology of China

CBM-China meeting 203 Nov. 2009

Index

R&D on MRPC (STAR TOF, STAR MTD, …) Long-strip MRPC for CBM August test at GSI Summary and Outlook


Early R&D (2000-2002)

beam test at PS-T10, CERN ： efficiency >95% （ 5 gas gaps ） >97% （ 6 gas gaps ）

~ 99% （ double stack 2 5 gas gaps ） time resolution ~70ps （ 5 gas gaps ） ~60ps （ 6 gas gaps ）

~50ps （ double stack 2 5 gas gaps ）

M.Shao, L.J.Ruan, H.F.Chen et al.,

NIM A492(2002)344-350

MRPCs of different structures

60

working gas mixture: F134A(90%) ＋ iso- C4H10 (5%) ＋ SF6(5%)


STAR Upgrade -PID

TPC- tracking

MRPC TOF (TOFr) – stop time measurement

VPD - start time measurement

Particle momentum; dE/dx

~8% resolution

/K separation to ~0.6GeV/c

k/p separation to ~1.0GeV/c

Aim at 100ps time resolution TOF system

/K separation to ~1.6GeV/c & k/p separation to ~3.0GeV/c


MRPC strip size ：3.15cm×6.30cm

Module size ： 21.2×9.4×1.79 cm3

Gas gap ： 6×0.22mm

In 200 GeV central Au+Au:Time resolution <100ps Efficiency 90%High granularity Rate >200Hz/cm2

MRPC Structure for STAR/TOF


MRPC Mass Production After STAR Construction Readiness Review in April 2006, M

RPC mass Production in China started. University of Sci. & Tech. of China (USTC) will produce 1210 MRPCs

1/2 3/4 5/6 7/8 11/129/10 1/2 3/4 5/6 7/8 11/129/10 1/2 3/4 5/6 7/8

2006 2007 2008

Prod. Start

40 MRPCs

+192 MRPCs

+326 MRPCs

+326 MRPCs

+326 MRPCs


100 m2 clean room ( cleanness class 100K ): Temperature ： 25o C Humidity ： <40% 4 assembly desk ( cleanness class 100 )

USTC site - MRPC Mass production


QC setup – cosmic ray telescope

QC capability: 8 MRPCs / Day


Monthly output

2006

Month Output

2007

Month Output Month Output

Jun. 12 Jan. 58 Jul. 120

Jul. 64 Feb. 24 Aug. 120

Sep. 55 Mar. 83 Sep. 119

Oct. 35 Apr. 80 Oct. 121

Nov. 42 May. 126 Nov. 120

Dec. 22 Jun. 82

Total 230 1053

Totally, 1283 MRPCs have been produced.


Long time stability

More stable at late production stage


TOF Time Resolution Summary

2003 to 2009 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


STAR/MTD

A large area of Muon Telescope Detector (MTD) at mid-rapidity, allows for the detection ofdi-muon pairs from QGP thermal radiation, quarkonia, light vector mesons, and Drell-Yan production single muons from their semi-leptonic decays of heavy flavor hadrons

advantages over electrons: no conversion, much less Dalitz decay contribution, less affected by radiative losses in the detector materials


10 x 0.25 mm gas gaps in 2 stacks

Glass thickness : 0.71 mm

LMRPC -- side view

Design and construction

256mm

(150kΩ/ �)

950mm

Signal readout

anode

cathodeShort

side

Long side LMRPC PCB -- top view

Size: 950 x 256 mm2

Read out strip: 25 mm wide, 4 mm gaps between strips

Active area: 870 x 170 mm2


Photos of construction


MWPC5MWPC1 MWPC2

MWPC4

TOF1

252” 73”

TOF2

72” 164”449”

LMRPC

GEMsMWPC3

191”56 3381

TOF370”

Upper stream

Down stream

C1, C2

Beam Energy: 32 GeV

FNAL Beam Test (T963)

Beam test setup


Efficiency plateau

Results at T963 - I

Time resolution

60


Results at T963 - II

Using the tracking, we get the signal propagation velocity:

~ 60ps/cm

The half time difference of 2 ends of a strip:

σΔT/2 ~ 1.1 channel (55ps)

Position resolution: ~ 1 cm

Position resolution

3 prototypes working very well in STAR since 2007


Long-Strip MRPC for CBM

Used in relative low track density environment to save electronics channels

Read out at two ends Mean time Eliminate the position along the strip Time difference

Position information Easy to construct for large area coverage

Three Prototypes was test in August at GSI The main focus: Cross-talk performance


MRPC structure (endview)

5 x 250μm gaps

5 x 250μm gaps

Readout strips

HV

2.5cm

Readout strips: 2.5 cm x 50 cmHV electrode: Licron spray ~40 MΩ/□

Made of window glass of 0.7 mm thick


MRPC #1 (topview)

55 cm

24.1cm

2.5cm

0.6cm

Gaps between strips: 0.6 cm


MRPC #2 (topview)

Top/bottom pcb

The readout strips are “hollowed-out” alternately.

Removed: 5 mm x 4

Left: 1 mm x 5

Removed: 2.5 mm x 9

Left: 0.25 mm x 10


MRPC #3 (topview)

55 cm

24.1cm

2.5cm0.7cm

Gaps between strips: 0.7 cm (upper part)

0.8 cm (lower part)

0.8cm


ADC1 ADC2

ADC3 ADC4

<t 1

-(t 3

+t 4

)/2>

ADC1

<t 2

-(t 3

+t 4

)/2>

ADC2

<t 3

-(t 1

+t 2

)/2>

ADC3ADC4

PMT calibration

<t 4

-(t 1

+t 2

)/2>

((t3+t4)-(t1+t2))/4

Resolution~67 ps


T-(t1+t2+t3+t4)/4

T-(t1+t2+t3+t4)/4

T-(

t1+

t2+

t3+

t4)/

4ADC

<T-(

t1+

t2+

t3+

t4)/

4>

ADC

MRPC CalibrationIntrinsic timing resolution = 67 ps (including momentum spread)


Efficiency and resolution plateau

65 ps

97%


Position scan (±7 kV)

No significant efficiency drop in the gap

Trigger Area: 2 cm wide

From both “charge sharing” and cross talk.


Cross Talk

Trigger on the strip center:

“Cross talk” at neighbor strips: 3%

Trigger Area: 2 cm wide

“Cross talk” at next-to-neighbor strips: ~2%

Require valid TDC on two ends


TDC vs. QDCValid TDCs and valid QDCs (3 sigma above pedestal)

Valid TDCs


MRPC #2

Valid TDCs and QDCs


Efficiency vs. Position

Valid TDCs


Valid TDCs and valid QDCs (3 sigma above pedestal)


MRPC #3


Efficiency vs. Position

Valid TDCs


Summary USTC has experience on MRPC

technology. Capability of mass production Manpower on online QA, calibration,

related physics analysis CBM RPC-TOF?

Thank

you!


Documents

Long-strip MRPC for CBM