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http://him.phys.pusan.ac.kr/~hipex
RICH R&D status Report -I: Measurement of MAPMT uniformity
and electron Beam Profile Study at the Pohang Accelerator Lab.
27. Feb. 2008Hayoung LEE
Department of Physics, Pusan National University
Heavy Ion Physics Experiment LAB
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http://him.phys.pusan.ac.kr/~hipex
1. Motivation
2. Uniformity measurement with a new method
3. Result
4. Conclusion & Outlook
1. Motivation
2. Blinking Target + CCD camera
3. Scintillator
4. Conclusion & Outlook
1. MAPMT uniformity
2. e-Beam Profile
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8×8 MAPMT(HAMATSU,H8500)
[A Ring Imaging Cherenkov detector]
1. Motivation
<MAPMT (HAMAMATSU)>
What is uniformity?
[HAMAMATSU uniformity][ Hamamatsu Method]
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2. Uniformity measurement a new method
PMT
Uniform Light
Diffuser2
Diffuser1
Diffuser3
[light intensity distribution after diffuser]
Blue LED set
2mm
5.75mm4.51mm
2.56mm
2.55mm2.6mm
Diffusers set
X
Y
Z Diffuser set
USB2000
X
Y
Z
(x,y,z) = ( 0, 0, 340)
(x,y,z)=(0,1000, 375)
[Blue LED (λ= 472nm)]
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2. Uniformity measurement with a new method
H8711Pixel 4*4
Effective area [mm2] 18.1*18.1
H8500Pixel 8*8
Effective area [mm2] 49*49
LED
Inverter
4V
PMT
(H8711/H8500) Amp
.
Pulser Atten.
Gate generator
Q
D
CDAQ
[Circuit]
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3. Result[16 pixel MAPMT] [64 pixel MAPMT]
NormaliNormalizeded
NormaliNormalizeded
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4. Conclusion & Outlook
1. New diffuser method : quite good
2. Single photo electron measurement is required :
Polarizer and analyzer method
3. Why tiny systematic differences?
: Unknown Two correction table used, respectively.
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1. e-Beam at PALElectron beam at the TEST LINAC,
PAL (Pohang Accelerator Lab.), Korea. ; (Pe≈ 60MeV/c)
Bending Maget
Currunt : 25.2A
Beam window
[Experiment setup]
Z
X
Y
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2. Blinking Target + CCD camera
[Top view / 단위 : mm]
22cm
10cmBeam line
Table 1.
Table 2.
y
xSet1.
Set3 .
z
(400,200, 2920)
(400,200, 50)
(400,200, 2120)Set2 .
7cm
10.5cm
22cm
5.5cm
8cm
10cm
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3. Scintillator [60MeV/ Bunch size 1µs]
1.bending magnet current dependency- Scintillator : fix at beam window center
[25.2A][20A]
[13A]
[beam window]
[bending magnet]
[bending magnet]
cou
nts
QDC channel [A.U.]
Bending magnet current dependency – raw data
13A20A
25.2A
Bending Magnet Currunt Dependency
2000
2500
3000
3500
4000
10 15 20 25 30
Bending Magnet Currunt [A]
QD
C[fi
t m
ean][Beam line]
-------
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5. Scintillator Test2. Scintillator position dependency-bending magnet current : fix in 25.2A
0cm(center)
-8cm
-4cm
[60MeV/ Bunch size 1µs/]
cou
nts
QDC channel [A.U.]
Scintillator position dependency – raw data
-8cm
-4cm
0cm(center)
Scintillator position Dependency
0
1000
2000
3000
4000
- 10 - 5 0 5 10
Scintillator position from the Center [cm]
QD
C
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6. Conclusion &Outlook
1. Beam size is very large
2. Beam gets broader
3. Our detector is aligned at the beam center.
Conclusion
What-to-do
1. Deep into beam study
-*1) Precise Profile measurement (x, y, z) needed
-*2) New Beam profile detector : Mini MWPC Beam Trigger
2. A lead collimator (L> 15cm)
Lead 15cm
