1. Liverpool Group presentation 22/07/2009
SiPM response: experimental results In collaboration with LSN-University of Catania and STMicroelectronics-Catania
SiPM response: experimental results In collaboration with the University of Catania
Liverpool Group presentation 22/07/2009
Liverpool Group presentation 22/07/2009

2. Overview SiPMs and beam loss monitor From a single SPAD to a SiPM (1)
SiPM models
Realization of the amplifiers and SiPMs signal readout board
Dark count
SiPM to a pulsed laser signal
Measurements of rise time and recovery time
Conclusions
Liverpool Group presentation 22/07/2009
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3. SiPMs and beam loss monitor
Multimode step index fibers
SiPM directly coupled to the fibers
Liverpool Group presentation 22/07/2009
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4. From a single SPAD to a SiPM (1)
Semiconductor junction with a reverse bias few Volts above VBD.
Depletion layer E higher than 3x105 V/cm: a single carrier can trigger a self-sustaining avalanche.
A few mA current pulse with sub-nanosecond rise time is sharply produced.
The voltage is restored to the bias value and the device is ready to detect another photon quenched the avalanche by using a large resistor (passive quenching) or a suitable circuit (active quenching).
OXIDE
METAL N+
Gettering P+
Sinker S P A D
Liverpool Group presentation 22/07/2009
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5. From a single SPAD to a SiPM (2)
Matrix of n pixels in parallel
Every pixel gives the same signal when it is hit by a photon but the output charge is proportional to the number of triggered cells, i.e the number of injected photons: Qout=C(VR – VBR) Nfired
Analog device S I P M
Liverpool Group presentation 22/07/2009
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6. SiPM models STMicroelectronics (Catania) Photonique SA-Switzerland
Blue range
Visible range
Active surface 1mm2
Number of cells ~500
Fill factor > 70%
Liverpool Group presentation 22/07/2009
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7. Realization of the amplifiers and the signal readout board
High gain amplifier (Photonique AMP_0604)
Signal rise time ~5ns (5000ps), Amplification 20x...60x
High Rise Time amplifier (Photonique AMP_0611)
Signal rise time ~700ps, amplification 10x...20x
Catania very high gain amplifier
Amplification 10x...200x
Liverpool Group presentation 22/07/2009
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8. Dark count amplitude (mV)
Dark count measurements : repetition frequency and dark peak amplitude
Dark noise rate originates from the carriers thermically created in sensitive volume and also due to the effects of high electric fields. The SiPM dark rate increases with temperature.
SiPM
Dark count amplitude (mV)
Blue Phot 20
Vis Phot
ST modF 25
ST mod H 30
1 ph
2 ph
Liverpool Group presentation 22/07/2009
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9. SiPM response to a pulsed laser signal
Laser features:
Wavelength: 408 ± 10 nm
Spectral width (Δλ) <7nm
Pulse width <60 ps
Peak power in collimated beam (mW) >140
Tune: [0,100] %
Repetition frequency: 10Hz-1MHz
Experiments:
Fixed tune and variable rep frequency
Fixed rep frequency and variable tune
Liverpool Group presentation 22/07/2009
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10. SiPM response to a pulsed laser signal: fixed tune
1 kHz: a signal every 1ms
f= 5kHz: a signal every 200μs
1 MHz: a signal every 1μs
f=100 kHz: a signal every 10 μs
We have a coherent signal for every repetiton frequency between 10 Hz and 1 MHz
Liverpool Group presentation 22/07/2009
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11. SiPM response to a pulsed laser signal: fixed repetition frequency
Tune 100%
Tune 50%
Tune 4.4%
Tune 20%
The SiPM response is proportional to the injected photons until the Nph< Ncells : saturation
Liverpool Group presentation 22/07/2009
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12. SiPM response to a pulsed laser signal: rise time and recovery time
Rise time: time useful for triggering the avalanche
Recovery time: time useful for quenching the avalanche (dependent on the quenching circuitry used)
Liverpool Group presentation 22/07/2009
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13. Conclusions
We mounted the read-out electronics of SiPM and we tested the SiPMs for observing their response to:
Different amplifiers
Dark count
Timing response between 10 Hz and 1 MHz with a pulsed laser signal
Rise time and recovery time
Liverpool Group presentation 22/07/2009
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14. Thank you very much for your attention
Liverpool Group presentation 22/07/2009
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