Transcript Slide 1
TRD2005,Bari,10.09.05 Progress report on SiPM development and its applications Boris Dolgoshein Moscow Engineering and Physics Institute [email protected] Single photon Avalance Diodes(SPAD’s): S.Cova et al.,Appl.Opt.35(1996)19 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 h Silicon Photomultiplier (SiPM) 50 46 pixels fired Depletion 1-2m R 50 substrat e Multipixel (typically ≤ 1 mm2) Geiger mode photodiode with common readout Ubias NEXT STEP: Large area SiPM`s from 1x1 mm2 > up to 10x10 mm2 B.Dolgoshein,’Large area SiPM’s…’ 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 SiPM today-reminder: Pixel size ~20-30m 42m Working point: VBias = Vbreakdown + DV ~ 50-60 V DV ~ 3V above breakdown voltage 20m pixel h Resistor Rn=400 k -20M Al R 50 Depletion Region 2 m Substrate 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 Very fast Geiger discharge development < 500 ps Pixel recovery time = (Cpixel Rpixel) ~ 20 ns …1mks Ubias Dynamic range ~ number of pixels saturation 3x3mm SiPM parameters 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 0.4 electrons Single pixel recovery time: 1us After pulsing probability: appr. 1% Optical crosstalk: appr. 30 - 50 % ENF: appr. 1.5-2.0(overvoltage dependent) Spectral dependence of the photon detection efficiency (PDE) for different photodetectors 178nm-5.5%,(1mmx1mm SiPM) 40 one pixel gain (exp. data) one pixel gain (linear fit) detection efficiency ( =565nm) 30 10 20 5 10 0 0 One pixel gain M, 10 5 15 0 U breakdown 1 =48V 2 3 4 5 Overvoltage D U=U-U breakdown , V Photon detection efficiency= QE(~80%)x x packing efficiency(active/total area,~40%)x x Geiger efficiency(~70%) 6 Efficiency of light registration , % 20 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. 1000 nm B.Dolgoshein,’Large area SiPM’s…’ 1 32 mkm 64 mkm Optical crosstalk 0,1 96 mkm 128 mkm 0,01 1E-3 0 1 2 3 Gain, 10 4 6 B.Dolgoshein,’Large area SiPM’s…’ 5 Optical crosstalk,SiPM 1x1 mm2,dark noise 0 10000 SiPM 1 Z-type. U-Ubd=8V. kopt=1,85. tgate=80ns. Crosstalk==>non-Poissonian distribution: QDC LeCroy 2249A. Noise. 1000 Counts Gain 3x10**6 pixel fired/phe=1.7 100 ENF=1.6 10 1 200 400 600 800 1000 QDC channel 10000 Gain 3x10**7 events 1000 100 Crosstalk suppression by special SiPM topology: test structure,PRELIMINARY! Poisson distribution: pixel fired/phe= 0.98+-0.03 10 1 0 100 200 300 400 500 600 ENF= 0.97+-0.05 channel B.Dolgoshein,’Large area SiPM’s…’ Recovery time of single pixel: C(pix)xR(pix)-->20ns…..a few mks Recovery time. SiPM Z105 (U=60,13). Ubreakdown=52,4V. 13/01/2005 LED L53SYC (595nm), timpulse=10ns, Ugen=-9v, L=1sm. Amplitude of the second impulse, mV 2000 1800 Data: Data1_amp Model: ExpDecay1 Equation: y = y0 + A1*exp(-(x-x0)/t1) Weighting: y No weighting 1600 1400 1200 Chi^2/DoF = 565.44691 R^2 = 0.99897 1000 y0 x0 A1 t1 800 1932.69131 77.60337 -1926.00611 1615.08307 ±11.98254 ±-±-±37.05734 600 Charge first and second impulse arear = (-2,6:10) ns = -10,60622 V*ns one pixel arear = (-0,4:4)ns = -0,01907 V*ns Npixels = 556 400 200 0 0 2000 4000 6000 8000 10000 Distance between two light impulses, ns 12000 12 pixel gain MIP a) 450 10 400 9 350 8 300 7 250 6 200 8 10 12 14 16 18 20 0 Temperature T, C 22 24 20 5 26 pixel gain MIP b) 11 5 Pixel gain, 10 MIP, QDC channels MIP, QDC channels 500 1000 750 15 500 10 250 5 0 53 54 55 56 Bias voltage U, V Fig.5 Temperature and bias voltage dependence: delta T(V) Gain Signal=GainxPDE -1 C +2.2% +4.5% +0.1V +4.3% +7% 0 57 Pixel gain, 105 550 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) SiPM signal saturation due to the limited total number of Sipm’s pixels Number of pixels fired Response functions for the SiPMs with different total pixel numbers measured for 40 ps laser pulses 1000 100 576 1024 4096 10 1 1 10 100 1000 10000 Number of photoelectrons 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 SiPM long term stability 20 tested SiPMs worked during 1500 hours •Efficiency of light registration •One pixel gain •Dark rate •Dark current SiPM parameters Parameters under control: 10 3 10 2 10 1 10 dark rate, kHz efficiency of light registration, % gain (*106) 0 10 -1 10 -2 before tests after 500 hours after 1500 hours dark current, microAmper 0 2 4 6 8 10 12 SiPM number 14 16 18 20 + Low noise,high gain SiPM today: 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