Report on the KEK Laser systemand Test Bench @ Tsukuba

April-27 2006ILC-CAL meeting

S. Uozumi, T. Maeda

Laser Test Bench System @ KEK• YAG Laser• = 532 m (green)• Spot size ~ 1m• Pulse width ~ 2 nsec• Useful for Spot measurement,

but not for timing resolution

• 3/13~3/25 : System setup

by 中平、吉村、田口、馬塚、魚住 problem on trigger signal• ~4/20 : Photo diode installed for the

trigger signal, start measurement.• ~5/20 : Used by T2K group (田口くん )

100/400pixels(HPK), 600pixels(Russia)

• 6/1 ~ : We will start the laser

measurement.

KEK Laser – First Result (by 田口君 )

100μ

m

Laser　spot

• Results of the 100 pixel MPPC.• Measure efficiency / gain

inside a pixel, with 10 m pitch.

Gain : (only inside sensitive area)Efficiency (>0.5 p.e. / All)

～ 30μm

• 20 Russian SiPMs (600 pixels)

are available at KEK.• Test-bench system with thermostatic

chamber / LED is also available

KEK – SiPM samples

Gain ~ 4 x 105

Device-by-device variation seems not small.

20 SiPM characteristics

Test-Bench @ Tsukuba

• Just launched in last week• LED / thermostatic chamber

/ CAMAC / VME• Latest 400 / 1600 pixel

MPPC samples from Kobe

ゲインのバイアス電圧依存性(室温での測定 )

２つの４００ pixel MPPC

19106.163

)/(25.0

countpCdGain d

AMP 素電荷

ガイガーモード開始電圧

C = 0.13 ± 0.01 pFV0= -67.6 ± 0.01 V

)( 0VVe

CGain bias

ピクセル容量

Noise rate• 400 pixel MPPC• Threshold ~ 0.5 p.e.

Plans at Tsukuba• Evaluate fundamental performances of the latest MPPC samples

– Gain, noise rate, Linearity, P.D.E., cross-talk, dead-time– Its temperature dependence

• Bench test using laser system @ KEK– P.D.E./ Gain uniformity (Pixel-by-pixel / within a pixel)– Cross-talk– Its bias voltage dependence

• Practical test with strip scintillator / WLSF• Then provide feedbacks to HPK, and test newer samples

Short / Mid term … targets to the beam test in 2006/2007

• Long-term stability• Timing resolution• Absolute P.D.E., wave length dependence• Magnetic field test• Evaluate device-by-device characteristics

Long term …

今年度の筑波大 ILC メンバー : 金 , 魚住 , 前田 (M2), 4 年生 1 人

Backups

SiPM - ADC 分布

• ノイズレート～ 1MHz時の ADC分布• Single p.e.の S/N～ 2.0

– HPK製のものを同様に測ると S/N～ 4.3

• Pedestalの σ～ 8.9– エレキのノイズ等まだ多い？

Pedestal 1710-043 Vbias=-49.4V

1

1

/( ) 2

pe ped

pe ped

mean meanS N

Signal

SiPM - 波形

• 信号のタイミングがばらついている

1710-043 　　 Vbias=-49.4V Signa

lNoise

SiPM - ノイズレート

• Threshold： -17mV• ゲインと同様、逆バイアス電圧にほぼ比例• 0509series～ 800kHz/Vbias 1710series～

370kHz/Vbias

SiPM - カレント

• ゲイン、ノイズレート同様、逆バイアス電圧にほぼ比例• 0509series～ 0.27μA/Vbias 1710series～ 0.14μA/Vbias

• ゲイン・ノイズレート・カレントにおいて、 0509seriesの方が 1710seriesよりも逆バイアス電圧に sensitive

HPK製MPPC

• Sample 311-53-1A-002-3• Vbias=-69.0V noise ～ 1MHz• SiPM と同じ回路で測定• S/N ～ 4.3 　　　 c.f. 　ロシア製　～ 2.0• ゲイン～ 6.4×105 　　　　 c.f. 　ロシア製　～ 4.4×105

400pix MPPC - LEDに対する信号

１５０ nSec