MRPC-TOF
DEVELOPMENT
TCHoU workshop 2018
Taichi Ichisawa

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TCHoU workshop 2018

J-PARC HEAVY ION PROGRAM

Search low energy and high chemical potential area in QCD diagram
by collisions with fixed target.

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TCHoU workshop 2018

Multi-gap Resistive Plate
Chamber J-PARC
3.2m

Neutron detector
EMCAL

Toroidcoils
1m

RICH

MRPC-TOF

JHITS

J-PARC Heavy-Ion
Toroidal SpectrometerBeam4m

SVD

2t22m =p ( 2L

ZCAL
1.4m

GEM trackers1)
1✓70 70cm large and 30ps timing resolution is required
at 4m far from collision point.
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TCHoU workshop 2018

MRPC

✓Simple and reasonable.
✓Easy to make larger one.

1.Charged particle injection.

✓Timing resolution can be
improved by stacking more gaps.

2.Avalanche by strong electric ﬁeld.
3.Read induced signal from read-out pads.
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TCHoU workshop 2018

SET UPMRPC in gasbox
positron(cosmic ray)
Scintillators for trigger

5GHz Flash ADC
DRS4 evaluation board

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TCHoU workshop 2018

Data extraction

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TCHoU workshop 2018

Quality of signal▼Time diﬀerence between both ends of scinti

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TCHoU workshop 2018RECENT WORK
1.We created MRPC which became the ﬁrst large scale in ourlaboratory.(gap width 165μm,6gaps/stack,4stacks)
2.Tried impedance matching and introduction of devices for highfrequency reading.(gap width 260μm,5gaps/stack,1stack)3.Tried ﬁrst introduction of single-end preampliﬁer and real GND.
(gap width 260μm,6gaps/stack,1stack,split GND type)

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TCHoU workshop 2018

timing resolution(cosmic ray)

✓The best timing resolution ~50ps marked by 165μm.
✓The timing resolution increases as the number of stacks(N)increases.(timing resolution 1/ N)
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1.FIRST LARGE TYPE MRPC(positronbeam)▼Positron Beam Test@ELPH
timing resolution[ps]Timing Resolution(MRPC1&MRPC2)
4-stack 165µm
13.0 kV
14.0 kV
14.5 kV
15.0 kV

240
220
200
180

mrpc2 #99

160

mrpc1 #99

60
70

50

140

60

40120

50
40

30

100

30

20

20

10

80

10060
−150−10−10−10−50510

28

30

32

34

36

38

40

42

4430

32

34

3638

40

42

position[cm]gap width165μm,6gap/stack,4stacks large MRPC
Position dependence on timing resolution
timing resolution79.8 1.8ps@position5,15.0kV

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TCHoU workshop 201844

2.IMPEDANCE MATCH + SMA▼Diﬀerential impedance measurement(by SONY GM&O)

twist cable

padpadSMA connector

Impedance of preampliﬁer →50ΩTwist cable→SMA cable (50Ω)
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TCHoU workshop 2018

2.RESULT(cosmic ray)mrpc1:t3 {event==164}▼1stack+SMAcable

電圧(mV)
mrpc1

mrpc1:t3cable(original){event==14}▼1stack+twist

30

2040

ー 1stack+twistcable
1ー１stack+SMA cable30
20
100−1010−200−30−40−106466

6870

72

747678t3646668707278time(ns)rise time(ns)1stack+SMA cable76

t3time(ns)１stack+twist cable74

0.94 0.14
0.77 0.18

number of events

40

t7rise▼Rise time distribution

0.80.60.4

0.20−1012

rise time(ns)gap width 260μm,5gap/stack,1stack large MRPC
timing resolution : 268.8 17.0 ps @ 7.0kV,center position
50Ω SMA → Reduce reﬂection

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3.SINGLE-END PREAMPLIFIER+ REAL GND▼split GND type

✓Single-end preampliﬁer.
✓Introduction of real GND.
✓Structure for shielding external noise.

More noise resistance

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High frequency read-out

TCHoU workshop 2018

3.RESULT(cosmic ray)✓timing resolution : 213.9 6.6 ps@ 7.5kV,center position✓Impedance mismatch due tostructural change

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TCHoU workshop 2018

SUMMARY

4 stack

1 stack

split GND

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timingresolution(ps)@center position

improvedpoints

points to be
improved

114.1 1.9

upsizing

impedance match

268.8 17.0

・impedance
match
・SMA

・noise resistance・high frequency
preamp213.9 6.6

・increase pulse
・single-endheight
preamp・impedance・new structure
match
TCHoU workshop 2018

FUTURE WORK
Impedance match(split GND type)
To increase pulse height of the signal
・preamp gain optimization
・Increase the number of gaps
・Increase the number of stacks
Structural optimization
・pad size and shape

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BACK UP

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TCHoU workshop 2018

SET UP(宇宙線)
cosmic ray
or positron beam

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How to estimate timing resolution

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TCHoU workshop 2018

efficiency [%]Eﬃciency(4stack type)
100
90
80
70
60
50
40
30
20

13.0kV

1014.5kV

0−1514.0kV

15.0kV−10−5051015position [cm]number of events(pulse height>10mV)
Eﬃciency =20

number of all events
TCHoU workshop 2018

diﬀerential preamp

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TCHoU workshop 2018

Single-end preamp• frequency : 1MHz~6GHz• impedance : 49.9Ω
• gain : 19.5dB

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TCHoU workshop 2018