1

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

2

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

3

8×8 MAPMT(HAMATSU,H8500)

[A Ring Imaging Cherenkov detector]

1. Motivation

<MAPMT (HAMAMATSU)>

What is uniformity?

[HAMAMATSU uniformity][ Hamamatsu Method]

4

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)]

5

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]

6

3. Result[16 pixel MAPMT] [64 pixel MAPMT]

NormaliNormalizeded

NormaliNormalizeded

7

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.

8

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

9

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

10

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]

-------

11

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

12

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