Jun 13 – 15, 2012
LAL Orsay
Europe/Paris timezone

Delayed avalanches in Multi-Pixel Photon Counters

Jun 13, 2012, 11:35 AM
Amphithéâtre Pierre Lehmann (LAL Orsay)

Amphithéâtre Pierre Lehmann

LAL Orsay

Centre Scientifique d'Orsay - Bat 200 91898 Orsay cedex FRANCE
Oral presentation SiPM


Dr Fabrice Retiere (TRIUMF)


Hamamatsu Photonics Multi-Pixel Photon Counters (MPPCs) achieve high photodetection efficiency with relativelity low dark noise. The MPPC gain is comparable to Photomultipliers but but the pixel avalanches tend to trigger others either in neighboring pixels (crosstalk) or in the same pixel at a latter time (after-pulsing). Cross-talk and after-pulsing avalanches are one of the main limitation of MPPCs preventing operation at large operating voltage. Crosstalk avalanches are thought to be due to optical photons created in the avalanche and absorbed in a neighboring pixels. On the other hand, after-pulsing avalanches are thought to be due to charge carriers produced in the avalanches that become trapped on impurities and released at latter time. We investigate the possibility that after-pulsing avalanches are also due to visible photons created in the avalanches but absorbed in the silicon bulk rather than in neighboring pixel high field region. Then, the charge carriers created in the silicon bulk diffuse back to the high field region, yielding delayed avalanches. The MPPCs were illuminated with laser light at wavelength ranging from 404 to 820 nm and the timing distribution of the avalanches was measured. Delayed avalanches were observed at 637 and 820 nm showing that some holes do diffuse to the high field region. Simulations show that optical photons are responsible for at least half of the after-pulsing avalanches. The data also shows that the MPPC single photon timing resolution cannot be described by a simple Gaussian distribution.

Primary author

Dr Fabrice Retiere (TRIUMF)


Mr Kyle Boone (University of British Columbia)

Presentation materials