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New MPPC sample recently we got
• HPK32(400pixel) ×3
Operating voltage : 68~69V
1p.e signal width:~20ns
• HPK53(100pixel) ×3
Operating voltage:68~69V
1p.e signal width:~50ns
•HPK say these have higher PDE than old samples
•The test result of HPK14(100pixel) that we used at beamtest will be presented for comparison
Noise rate measurement
15℃
20℃
25℃
■ 0.5p.e threshold ▲ 1.5p.e threshold
1MHz
100kHz
68.4 68.4 69.6 69.4
15℃
20℃
25℃
Bias voltage Bias voltage
HPK32(400pixel) HPK53(100pixel)
Gain measurement@T=20℃
HPK53(100pixel)
HPK32(100pixel)
1×106
3×106
1MHz500kHz
gain
0.5p.e threshold noise rate
HPK14(100pixel)
•Gain of new samples >105,so satisfy T2K requirement
Crosstalk rate measurement@T=20℃
0.5p.e threshold noise rate
1MHz500kHz
0.2
Crosstalk rate HPK53(100pixel)
HPK14(100pixel)
HPK32(100pixel)
0.1
•Crosstalk rate of new samples is still high
(T2K requires crosstalk rate<0.1)
PDE measurement@T=15℃
MPPC
½inch PMT
scan1mmφslit
MPPC
½inchPMT
scan
1mmφfiber
Blue LED
Blue LED
1mmφfiber
•With this set up all the light going through 1mmφslit inject to the active area of MPPC
•With this set up some light from a fiber don`t reach to the active area of MPPC because there is a distance(~0.8mm) between surface cover and active area
•Ratio of MPPC p.e to PMT p.e measured by this set up is defined as PDE
•Ratio of MPPC p.e to PMT p.e measured by this set up is defined as effective PDE
PDE measurement@T=15° ▲ PDE
Noise rate(kHz)
ノイズレート(kHz)
ノイズレート (kHz)
•PDE is showed with relative value to PMT
900
500
2
HPK53(100pixel) HPK32(400pixel) HPK14(100pixel)
900500 900550 400 900Noise rate(kHz) Noise rate(kHz)
2
1
■ effective PDE
•PDE of new sample is 2 times larger than that of old one•Effective PDE is 50~60% of PDE We requested the improvement of MPPC packaging to HPK
Raw signal of new sample
HPK53(100pixel) Noiserate=1345kHz
HPK32(400pixel) Noiserate=1246kHz
•Noise with large pulse height ( ~ 10p.e) is observed when noise rate becomes >1MHz
•There is no problem because T2K requires noise rate <1MHz
Long term stability test@T=20℃
4 layers
½ inch PMT
HPK32(400pixel)
Cosmic ray
Bias voltage 68.8V
gain 5.6×105
0.5p.e th noiserate 800kHz
Crosstalk rate 0.1
Effective PDE(including crosstalk)
1.2
Trigger counter
•Cosmic trigger
•LED trigger(for monitaring MPPC gain)
•Pedestal trigger(for monitaring noise rate)
Blue LED
•Test the stability of gain,noise rate,p.e for MIP
MPPC parameter
3 different triggers
gain
5%
5%
RMS/mean=2.5%
5%
5%
40hour 40 hour
Noise rate
5.7×105
839kHz
Stability of MPPC gain and noiserate
RMS/mean=4.3%
Peak adc count for MIP
5%
5%
Peak adc count/gain for MIP
5%
5%
Stability of MPPC Light yield for MIP
RMS/mean=4.0% RMS/mean=2.9%
14.7p.e
40 hour 40 hour
Correction by gain
summary
• New MPPC samples have about 2 times larger PDE than that of old ones
• MPPC light yield for MIP~15p.e (at the point where noise rate and gain satisfy T2K requirement)
• Gain stability ~3% ,noise rate stability~4%
• Stability of light yield for MIP~3%
(about 2 days)
5%
5%
40hour
Peak adc count for MIP Peak adc count/gain for MIP
5%
5%
16.5p.e
Stability of PMT light yield for MIP
40hour
RMS/mean=4.6% RMS/mean=3.1%Correction by gain
Operating voltage range which satisfy T2K requirement
•HPK32(400pixel)
68.2 ~ 68.8V
Upper limit : 1.5p.e th noise rate<50kHz
Lower limit : PDE >15%
•HPK53(100pixel)
68.3 ~ 69.1V
Upper limit : 1.5p.eth noise rate<50kHz
Lower limit : PDE>15%
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