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SiPM read-out for time-of-flight PET


Petiroc 2A is a 32-channel front-end ASIC designed to readout silicon photomultipliers (SiPM) with both polarities for particle time-of-flight measurement applications. Petiroc 2A combines a very fast and low-jitter trigger with accurate charge and time measurements. Energy and time are digitized internally with a 10-bit ADC and 40ps-bin TDC.
The concept of the ASIC is to combine two measurement lines that won’t interfere one with each other to measure both first incident photon timing measurement and whole crystal light charge integration.
An adjustment of the SiPM high voltage is possible using a channel-by-channel input DAC. It allows a fine SiPM gain and dark noise adjustment at the system level to correct for the non-uniformity of SiPMs.
The power consumption is 6 mW/channel, excluding buffers used to output the analogue signals. The main application of Petiroc 2A is PET time-of-flight prototyping but it can also be used for any application that requires both accurate time resolution and precise energy measurement.


TRL Technology Readiness Level  6 - Application prototype available - learn more
 Available versions
  • Petiroc 2 : discontinued 
  • Petiroc 2A : available
Detector Read-Out  SiPM, SiPM array
Number of Channel 32
Signal Polarity Positive or Negative
Sensitivity Trigger on first photo-electron
Timing Resolution  below 40ps

Packaging & Dimension 

  • TQFP 208 28x28mm
  • TFBGA353 12x12mm
Dynamic Range 3000 photoelectrons (106 SIPM gain), Integral Non Linearity : 1% up to 2500 photoelectrons
Power Consumption

Power supply : 3.3V

192mW Analogue cire (excluding outing buffer), 6mw/ch.

Inputs 32 voltage inputs with DC adjustment for SiPM HV tuning
  • Digital output (energy on 10 bits, time on 10 bits - 40ps bin)
  • 32 trigger outputs
  • 1 multiplexed charge output, 1 multiplexed hit register
  • 2 ASIC trigger outputs (Trigger OR on 32 channels, 2 levels)
Internal Programmable Features
  • 32 HV adjustment for SiPM (32X8bits)
  • trigger threshold adjustment (10bits)
  • charge measurement tuning
  • 32 trigger masks
  • internal temperature sensor
  • trigger latch
Evaluation systems
  • Evaluation board : available
  • CAEN system : DT5550A - to be released soon
  • Gammacam : integrated evaluation system - in design