Study of Par,cle ID in Liquid Scin,llator using Imaging Detector
Tohoku Univ. RCNS Takayuki Takai takai@awa.tohoku.ac.jp

Mo=va=ongamma

beta

Mo=va=on of par=cle iden=ﬁca=on in liquid scin=llator• Background reduc=on• Detec=on eﬃciency improvement

There is diﬀerence of the lightemission in liquid scin=llator…
β : captured soonγ : causes compton sca^ering

RMS

Par=cle iden=ﬁca=on with imaging detector is the new
method as the improvement of detector. It makes todis=nguish beta-ray and gamma-ray possible!

RMS

Beta-ray event

Imaging Detector
Liquid scin=llator
Detector

The posi=ons of light emi^edis one of the parameter for
par=cle iden=ﬁca=on!

Gamma-ray event
Liquid Scin=llator

Imaging Detector

Liquid Scin=llator

Setup for demonstra=on

Imaging detector prototype

Beta-ray

Op=c

Imaging Detector

10L LS

Keigo’s poster men=ons status of op=c.

Mul= Pixel Photon Detector

Gamma-ray

Requirement• 1p.e. sensi=vity• Low darkrate• Ease of expansion

1m

Energy deposit

Trigger
Mul= Anode PMT

The ﬁrst candidate is…

Imaging Check

MAPMT (Mul= Anode PMT)

FlashADC

5inch PMTElectrode structure andelectron trajectories

Data Processor

Event Photo
Gamma-imaging

Beta-imaging

Histograms show the hit count 16
14about all taken photo.
12It means success of beta-ray 10
8and gamma-ray imaging
6sta=s=cally.
42I must analyze taken photos
00 2 4 6 8 10 12 14 16
one by one about its RMS.

16
1800
1600

500

14400

1400 121200 10
1000
800

300

8200

6600

4100

400
200

20002468 10 12 14 16

liquid scin=llator box range

Mul= Anode PMT informed us
photon hit posi=on as a pixel.

Dark rate measurement
16Expansion

1014
1281068616

Data Processor (VME module for mul=anode PMT) can control some MAPMTs inparallel. It makes easy to develop mul=imaging detector.

[rate]

14RMS2!"
r12

4

61.4
10

Monte Carlo Simula=on
25
20
15
105

Observa=on shows slightly
posi=ve result. Next, I am
verifying the result by Geant4
simula=on (Monte Carlosimula=on tool).

6050
40

60
0<540<10<1520<200<25<25<20<15<10 <5 0 5 10 15 20 2525140201201510100580060<5<1040<1520<200<25<25<20<15<10 <5 0 5 10 15 20 25258020157010605z=100mm

Graph
RMS comparison

3.532.5z=150mm

21.550

Reproduced
CCD camera
Design1

0.50z=-150mm

70z=-100mm

It is necessary that Op=c is reproduced precisely
in Monte Carlo simula=on. I adopted aberra=on
from LED images taken by CCD camera.

z=0<150<100< 500410<20.6!"
r2CCD camera

Reproduced030<5<1020<1510<200<25<25<20<15<10 <5 0 5 10 15 20 25
2520
100
1580
105

Reproduced Op=cRMS[mm]

0.8

0.4
0.2
68

10

1214

16

10<30!
!"!
Root Mean Square (unit: pixel) !"1r = N ∑i n i × r i
r : hit posi=on
n : p.e. each r
!"
!
!"
!
1
N : sum of p.e.
RMS =− r
∑
ni ri
N i
<r> : center of mass

Dark rate (all pixel) ~ 200 Hz.
Accidental hit rate became 0.0002.
It is enough to use as a photon detector.

LED (Blue)

1!"
r3

62

10<1

1.2!
r828 10 12 14 1650100150z[mm]040<530<1020<1510<200<25<25<20<15<10 <5 0 5 10 15 20 25

Gamma-events havelarge propor=on

1200211.642

Beta-events have large propor=onp.e.

1.84400Analysis() 10<4()

2Beta
Gamma

0 1 2 3 4 5 6 7 8 9 10

Summary&ToDo
Summary• Prototype of imaging detector has been made.
• Demonstra=on for Par=cle iden=ﬁca=on has beendone.
• Beta-ray and Gamma-ray imaging was successful.
• The diﬀerence of RMS histogram was found.

ToDo• Monte Carlo simula=on should be ﬁnished.
• In demonstra=on, There are many background events.
I iden=fy background source and evaluate its eﬀect.
• I will suggest more suitable setup for par=cle
iden=ﬁca=on.