pde of 1600-pixel mppc
DESCRIPTION
PDE of 1600-pixel MPPC. Sudo Yuji Tsukuba Univ. 2007.1.23. MPPC. LED. WLSF. PMT. Φ 0.5. Photon Detection Efficiency ( PDE ). ~ a probability that detect a photoelectron for one photon. Q.E. : quantum efficiency that is a probability of - PowerPoint PPT PresentationTRANSCRIPT
PDE of 1600-pixel MPPC
Sudo Yuji Tsukuba Univ.
2007.1.23
Photon Detection Efficiency ( PDE )
• Q.E. : quantum efficiency that is a probability of
creation of a pair of e- h+ for one photon Geiger : a probability that arise avalanche for electron
geom : a proportion of effective region in a sensor
Measurement method• Relative # of p.e. for reference PMT
~ a probability that detect a photoelectron for one photon
geomGeigerMPPC EQ ..
MPPC
PMTΦ0.5
LEDWLSF
PMTPMTep
MPPCep
MPPC N
N
..
..
Set up
Gate
Generator
Delay
Voltage
source
HV
PMT
MPPC
Stage
WLSF
Green
LED
AMP *63
Signal
input
Gate
PC
Thermo-static chamber
Clock
Generator
Voltage
source
Light yeild measurement( with noise and cross-talk subtraction)• Measure light yeild of
LED light pulse
• Fit ADC distributon
• Supposed signals are dominated by Poisson statistics
• Count number of events below 0.5 p.e. threshold ( both LED on and off )
pedestal Events
0.5 p.e. threshold
0.5 p.e. threshold
pedestal Events
Calculation of Np.e.
• f(0,μLED on) = f(0, μ+μnoise)
= f(0,μ) × f(0,μnoise)
f(0,μ) = f(0,μLED on) / f(0,μnoise) = e-μ
μ = -ln( f(0,μ) )
• f(n,μ) is Poisson distribution function
• μ is Expectated number of Np.e.
• f(0,μLED on), f(0,μLED off ) are probability of 0 p.e.
f(0,μnoise) = NLED off / NLED off = e-μnoise
f(0,μLED on) = NLED on / NLED on =e-μLED on
pedestal all
pedestal all
NpeMPPC / NpePMT (Npe ratio)
WLS Fiber Y-11
Reference : JLC ストリップ・ファイバー電磁カロリメータの性能研究
関口克巳 平成 15 年 3 月
QE of H1161GS
Mean of QE for 1 p.e.QE × relative light yeild on each wave length
∑ ( QE × relative light yeild on each wave length )
= Mean of QE for 1 p.e. ~16.7 %
Max
Min
Photon Detection Efficiency ( PDE )
• PDE of PMT is ~ 16.7 %
• 6.3 % uncertainty cames from estimation of PMT P.D.E
±~ 6.3 %
PMTPMTep
MPPCep
MPPC N
N
..
..
Summary• We measured PDE of a 1600-pixel MPPC.• P.D.E increases with over voltage ( Vbias – V0), and s
aturated around 23 %.• But we don’t know correct QE data and light yeild di
stribution of a WLS fiber ( Y-11 ) .• It gives uncertainty of 6.3% on the P.D.E measurem
ent.• We will have three PMTs on 2/14 that have QE data
which are measured by HPK .• For further improvement, We should use light sourc
e which emits well-known wave length , otherwise we have to measure spectrum of wave length emitted by WLS fiber.
Buck up