1. Progress report on SiPM development and its applications
TRD2005,Bari,
Progress report on SiPM development
and its applications
Boris Dolgoshein
Moscow Engineering and Physics Institute

2. Single photon Avalance Diodes(SPAD’s): S. Cova et al. ,Appl. Opt

3. Silicon Photomultiplier (SiPM)
TWO STEPS IN DEVELOPMENTS OF GEIGER MODE APD:
FIRST STEP: SINGLE PHOTON AVALANCHE DIODE (SPAD), based on single pixel “photon counter”
SECOND STEP: from SPAD to
Silicon Photomultiplier (SiPM)
R 50 h
substrate
50
Ubias
46 pixels fired
Depletion
1-2m
Multipixel
(typically ≤ 1 mm2) Geiger mode photodiode with common readout
NEXT STEP: Large area SiPM`s from 1x1 mm2 > up to 10x10 mm2
B.Dolgoshein,’Large area SiPM’s…’

4. SiPM’s have been developed in Russia during last
~10 years(see International Conferences on New
Developments in Photodetection ICNDP-1999,
2002,2005)
There are four SiPM’s producers for the time
being-at the level of test batches production:
Center of Perspective Technology and Apparatus
CPTA,Moscow
MEPhI/Pulsar Enterprise,Moscow
JINR(Dubna)/Micron Enterprise
HAMAMATSU started the SiPM production last year

5. SiPM today-reminder: R 50 Ubias Pixel size ~20-30mm
Working point: VBias = Vbreakdown + DV ~ V
DV ~ 3V above breakdown voltage
Each pixel behaves as a Geiger counter with
Qpixel = DV Cpixel with Cpixel~50fmF  Qpixel~150fmC=106e
Electrical inter-pixel cross-talk minimized by:
decoupling quenching resistor for each pixel
boundaries between pixels to decouple them
 reduction of sensitive area
and geometrical (packing) efficiency
R 50 h
pixel
Ubias Al
Depletion
Region
2 m
Substrate
20m
42m
Resistor
Rn=400 k
-20M 
Very fast Geiger discharge development < 500 ps
Pixel recovery time = (Cpixel Rpixel) ~ 20 ns …1mks
Dynamic range ~ number of pixels  saturation

6. 3x3mm SiPM parameters Depletion region: appr. 1 m
Sensitive area : 3x3 mm2 # of pixels: 5625
Depletion region: appr. 1 m
Pixel size: 30 mx30 m
Working voltage: 20…25 V Gain: 1…2 x10**6
Dark rate.room temperature: 20 MHz
SiPM noise(FWHM):
room temperature 5-8 electrons
-50 C electrons
Single pixel recovery time: 1us
After pulsing probability: appr. 1%
Optical crosstalk: appr %
ENF: appr (overvoltage dependent)

7. Spectral dependence of the photon detection efficiency (PDE) for different photodetectors
178nm-5.5%,(1mmx1mm SiPM)

9. Photon detection efficiency= QE(~80%)x
x packing efficiency(active/total area,~40%)x
x Geiger efficiency(~70%)

10. –due to secondary light emitted
Optical Crosstalk OC
–due to secondary light emitted
in Geiger discharge: 10**-5 photons/one electron
adjacent pixels are fired- fig’s.
OC increases drastically with a Gain
becomes >1 for a Gain > few timesx10**7 selfsustening discharge
pixel independence and Poisson statistics of fired pixels
are violated
Excess Noise Factor ENF becomes too large
Secondary light:
Effective absorption length(Si)- appr. 50 mkm
Effective wavelength- appr nm
B.Dolgoshein,’Large area SiPM’s…’

11. B.Dolgoshein,’Large area SiPM’s…’

12. Optical crosstalk,SiPM 1x1 mm2,dark noise
Crosstalk==>non-Poissonian distribution:
pixel fired/phe=1.7
ENF=1.6
Gain 3x10**6
Crosstalk suppression by special SiPM topology:
test structure,PRELIMINARY!
Poisson distribution:
pixel fired/phe=
ENF=
Gain 3x10**7
B.Dolgoshein,’Large area SiPM’s…’

14. Recovery time of single pixel: C(pix)xR(pix)-->20ns…..a few mks

15. Temperature and bias voltage dependence:
delta T(V) Gain Signal=GainxPDE
-1 C % %
+0.1V % %

16. No Magnetic Field dependence at 1% level (Experimental data accuracy)
Comparison of the SiPM characteristics in magnetic field of B=0Tand B=4T
(very prelimenary, DESY March 2004)
LED signal ~150 pixels
A=f(G, , x)
No Magnetic Field dependence at 1% level
(Experimental data accuracy)

17. SiPM signal saturation due to the limited total number of Sipm’s pixels
Response functions for the SiPMs with different total pixel numbers measured for 40 ps laser pulses

18. Long term stability of SiPM
20 SiPMs worked during 1500 hours
Parameters under control:
One pixel gain
Efficiency of light registration
Cross-talk
Dark rate
Dark current
Saturation curve
Breakdown voltage
No changes within experimental errors
5 SiPM were tested 24 hours at increased temperatures of
30, 40, 50, 60, 70, 80, and 90 degrees
No changes within experimental accuracy

19. SiPM long term stability
20 tested SiPMs worked during 1500 hours
Parameters under control:
Efficiency of light registration
One pixel gain
Dark rate
Dark current

20. - + SiPM today: Low noise,high gain Good single electron resolution
Very good timing
Small recovery time
Very low nuclear counting effect
Insensitivity to B
Simple calibration and monitoring
Vow bias voltage
Low power consumption
Compactness
Room temperature operation
Good T and V stability
Simplest electronics
Relatively low expected cost(low
resistivity Si,simple technology)
Not very high PDE
Small area
High dark rate(~ area)
Exess Noise Factor is
large enough due to
Optical Xtalk