Aerogel radiator

Development of 144 Channel Multi-Anode HPD Development of 144 Channel Multi-Anode HPD for Belle Aerogel RICH Photon Detectorfor Belle Aerogel RICH Photon Detector

1I. Adachi, 2R. Dolenec, 2A. Petelin, 3K. Fujita, 2A. Gorisek, 3K. Hara, 3D. Hayashi, 3T. Iijima, 3K.Ikado, 4H. Kawai, 5S. Korpar, 3Y. Kozakai, 6P. Krizan, 4A. Kuratani, 3Y. Mazuka, 7Y. Miyazawa,

1S. Nishida, 8I. Nishizawa, 9S. Ogawa, 2R. Pestotnik, 8T. Sumiyoshi, 4M. Tabata, 3M. Yamaoka

1:IPNS, KEK, Tsukuba, Japan / 2:J.Stefan Institute, Ljubljana, Slovenia / 3:Dept. of Physics, Nagoya Univ., Nagoya, Japan / 4:Dept. of Physics, Chiba Univ., Chiba, Japan /

5:Faculty of Chemistry and Chemical Engineering, Univ. of Maribor, Maribor, Slovenia / 6:Faculty of Mathematics and Physics, Univ. of Ljubljana, Ljubljana, Slovenia /

7:Dept. of Physics, Tokyo Univ. of Science, Noda, Japan / 8:Dept. of Physics, Tokyo Metropolitan Univ., Hachioji, Japan / 9:Dept. of Physics, Toho Univ., Funabashi, Japan

presenter: Ichiro Adachi (ichiro.adachi@kek.jp)

Aerogel radiator

Position sensitive PDwith B=1.5Tesla

Cherenkov photon

200mm

n=1.05

Proximity Focusing RICH with Aerogel Radiator

Developed for new particle ID device in the Belle forward region• extend /K separation capability up to 4 at 4.0GeV/c• limited space• operational under 1.5 Tesla magnetic field

Key elements• Hydrophobic aerogel with refractive index of 1.050 as a Cherenkov radiator• Position sensitive photodetector

with ~5x5mm2 pixel size• Electronics for read-out

The present Belle detector

Principle of Operation Established at Test Beam Experiments

n=1.05 aerogel radiator

=14mrad Npe = 6 4 separation confirmed

4.0GeV“K”4.0GeV

typical event

RICH prototype counter

Hamamatsu Multi-anode Flat-Panel PMT(H8500)

/K 4 separation at 4 GeV/c achieved with a prototype counter

Multi-Anode Hybrid Photon Detector : Key Component

• High sensitivity to single photon• Immune to 1.5 Tesla magnetic field• Large effective area

Basic requirements

Hybrid (Avalanche) photon detector is our first candidateDeveloped with Hamamatsu Photonics

Package 72x72 mm2

# of pixels 12x12(6x6/chip)

Pixel size 5x5 mm2

Effective area 64 %

HAPD specifications

1 diode chip pixelated to 6x6 channels

72mm

72mm

= “bombardment” gain ~1000 x “avalanche” gain ~10single photon signal ~10000 electrons

ceramic tube

Experimental Set-up and Noise Level

Protector

H.V

144Ch HAPD

PreAmp

Shaping Amp

MCA

Pulse Generator

Light Shield Box

PC

LED

Coaxial cable

CathodeAnode

Bias Guard

ClearPulse 580K

ClearPulse 4417

Amptek pocketMCA

150pF

100MΩ

220MΩ

220MΩ222pF222pF

10MΩ

High Voltage

Bias Voltage

Reverse bias voltage supplied to cathodeSignal extracted from anode sideLED used as a light sourceOnly 1 channel read out, Others floated

Bias_scan

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

0 50 100 150 200 250 300 350 400reverse Bias voltage[V]

chipA chipB

chipC chipD

Bias_scan

500

700

900

1100

1300

1500

1700

1900

2100

0 50 100 150 200 250 300 350 400

reverse Bias voltage[V]

chipA chipB

chipC chipD

Noise level check by bias voltage scan

Full depletion observed at ~50V

Minimum noise level ~ 280VSimilar tendency for all of 4 chips

Diode chips show reasonable behavior

Pulse Height Spectra

HAPD

Response for single photon light

pedestal

1 p.e.

Clear signal observed

pedestal

1 p.e.

2 p.e.

3 p.e.

4 p.e.

5 p.e.

6 p.e.

7 p.e.

Response for multiple photon light

Total gain ~7,320S/N ~ 4.9

Chip-A ch#22 HV= -8.5kV & Bias=+319V

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ChipAChipA ChipDChipD

ChipCChipCChipBChipB

Target : ch22

- Bias=+340V

- Gain 〜 7,360

- S/N 〜 4.8

- Ava. Gain 〜 4.8

Target : ch22

- Bias=+340V

- Gain 〜 8,130

- S/N 〜 4.5

- Ava. Gain 〜 5.6

Target : ch22

- Bias=+360V

- Gain 〜 8,530

- S/N 〜 4.1

- Ava. Gain 〜 5.7

Target : ch22

- Bias=+319V

- Gain 〜 7,320

- S/N 〜 4.9

- Ava. Gain 〜 4.4

We can observe single p.e and S/N ratio is larger than 4.1 in all 4 chips.

H.V=-8.5kV

Uniformity & X-talk in Diode Chip

A

B C

D10

5

Single photon-equivalent light injected for all channels in one diode chip-A Uniformity of chipA

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

1 6 11 16 21 26 31 36# of channel

Gain or Noise [e]

2.00

3.00

4.00

5.00

6.00

7.00

8.00

9.00

10.00

11.00

total gain Noise S/N

S/NGainGainMaxMax〜〜 7,700@ch16 7,700@ch16 GainGainMinMin〜〜 6,310@ch316,310@ch31

S/NS/NMaxMax〜〜 6.2@ch8 , 21 6.2@ch8 , 21 S/NS/NMinMin〜〜 4.3@ch64.3@ch6

Noise avNoise av〜〜1,310[e]1,310[e]

Single p.e. can be observed for all channels (except for #5 and #10)

Gain ~ +/- 9%, S/N >~ 4.3, Noise ~1,300e

Channel #Gain/noise/S-to-N ratio calculated for each channel

Basic Properties for 4 Diode Chips from Our Measurements

Ch17Ch17

Ch16Ch16

Ch15Ch15

Ch23Ch23

Ch22Ch22

Ch21Ch21

Ch29Ch29

Ch28Ch28

Ch27Ch27

LED off

6 12 18 24 30 36

5 11 17 23 29 35

4 10 16 22 28 34

3 9 15 21 27 33

2 8 14 20 26 32

1 7 13 19 25 31

ChipA

Spot@ch22

2mm×2mmLED on

LED light illuminated to ch#22 through a small spot

Investigate pulse activities in neighbor channels for LED on/off

Negligibly small contribution in X-talk activities

Ch17Ch17

Ch16Ch16

Ch15Ch15

Ch23Ch23

Ch22Ch22

Ch21Ch21

Ch29Ch29

Ch28Ch28

Ch27Ch27

Conclusions References

We have developed a 144 channel multi-anode hybrid photon detector for a photo-sensor in the Belle aerogel RICH counter.New test sample delivered around the end of 2006 from HPK. Fundamental properties have been examined in our test bench.

Clear signal from single photon light has been observed, and total gain of ~7,500 was obtained.Reasonable uniformity of gain and signal-to-noise responses foundX-talk seems to be small

The next prototype having higher avalanche gain will be delivered soon.

1. T.Iijima et al., NIM A543(2001)321.

2. T.Matsumoto et al., NIM A521(2004)367.

3. T.Iijima, S.Korpar et al., NIM A548(2005)383.

4. I.Adachi et al., NIM A553(2005)146.

5. P.Krizan et al., NIM A565(2006)457.

QE = 24% from HPK measurementAvalanche gain calculated by total gain from our measurement and bombardment gain from HPK sheet

Delivered at the end of 2006 after technical improvements in HPK production process

except for noisy channels of #5 & #10