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Timing Measurements with SiPMs coupled to Scintillators

  • ToF-PET principle
  • ToF-PET principle
  • SiPM coupled to a 4x4x22 mm3 LYSO crystal
  • 2 Gamma detection modules in coincidence
  • Gamma Set-up Close-up
  • CRT 2009 - Optimized Layout
  • CRT 2011 - DLED
  • CRT 2012 - Optical CT Limit

Involved researchers

Time-of-Flight Positron Emission Tomography (ToF-PET) is one of the most important applications for the Silicon Photomultiplier, which is considered the most promising detector for replacing the traditional Photomultiplier Tube (PMT) in next-generation PET machines. For the ToF technique to be effective, a very good timing resolution is necessary so that the timing performance of the SiPM in the readout of the scintillation light is one of the most important parameters of the detector.


For this reason, we perform in-house timing measurments with our SiPMs coupled to scintillators, aiming at the characterization and the improvement of their performance for Time-of-Flight PET (ToF PET), using the Gamma-ray characterization bench of the SRS laboratory. From the data obtained form different detector layouts and process splits, we get useful indications for the improvement of subsequent detector designs.

Selected Results

  • In 2009, we developed a new sensor layout which allowed us to reach extremely good timing perfromance with a large area SiPM. We obtained a CRT of less than 320ps FWHMwith a 4x4mm2 SiPM coupled to a 3.8x3.8x22mm3 LYSO scintillator using a simple leading edge discriminator. (NSS 2010 presentation)
  •  In 2011, we showed that the detrimental effect of dark noise of SiPMs in timing measurements with scintillators can be drastically reduced by means of simple signal filetring. Very good CRT can be obtained with 4x4mm2 SiPMs developed at FBK. (NSS 2011 presentation)
  • In 2012, we showed how the optical cross-talk, enhanced by the presence of the scintillator, prevents from obtaining the best possible timing performance with a given SiPM. (NSS 2012 poster presentation)


Gola, A.; Piemonte, C.; Tarolli, A., "The DLED Algorithm for Timing Measurements on Large Area SiPMs Coupled to Scintillators," Nuclear Science, IEEE Transactions on , vol.59, no.2, pp.358,365, April 2012.

Gola, A.; Piemonte, C.; Tarolli, A., "Analog Circuit for Timing Measurements With Large Area SiPMs Coupled to LYSO Crystals," Nuclear Science, IEEE Transactions on , vol.60, no.2, pp.1296,1302, April 2013.

Gola, A.; Tarolli, A.; Piemonte, C., "SiPM cross-talk amplification due to scintillator crystal: Effects on timing performance," Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC), 2012 IEEE , vol., no., pp.421,423, Oct. 27 2012-Nov. 3 2012.

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