Skip to main content

Characterization of Silicon Photomultipliers for gamma ray spectroscopy
Report by Davide Rigamonti. Powered by FuseNet

My stay in Poland has been great! Just got off the train in Warsaw, the first thing I saw was the Palace of Culture and Science which was built right in the middle of the city and I immediately felt comfortable. In the last years the city went through a big modernisation which led to the construction of a large amount of skyscrapers.

The main aim of my research visit at the National Centre for Nuclear Research (NCBJ) has been to become familiar with the Silicon Photo-Multipliers and to improve my knowledge in radiation detectors; in particular in gamma ray spectrometers based on scintillation detector coupled to Silicon Photon-Multiplier readout.

Silicon Photo-Multiplier detectors (SiPMs), also referred as Multi-Pixel Photon Counters (MPPCs), are a relatively novel solid state photo-sensors which have experienced improvements in those last years. The MPPCs offer low voltage operation (< 100 V), high internal gain (105 - 107), high photon detection efficiency, high-speed response, insensitivity to magnetic field and mechanical robustness. Of course, they also have some drawback mainly concerning to the noise effects as cross-talk, after-pulses and dark noise and furthermore they show a temperature dependence and a strong sensitivity to the bias voltage. The excellent photon-counting capability of the Silicon Photomultipliers and its compact size, led us to investigate more about this device in view of its implementation in the gamma camera at the Joint European Torus (JET).

During my stay at the NCBJ, the first part of the experimental work was focused on the characterization of different Hamamatsu MPPCs. For this purpose, the I–V characteristic curve, the Vbd and the excess noise factor were established. Interesting was the study of the temperature dependence of the SiPM, which shown that small temperature changes can affect the operation of the silicon photomultiplier. The second part of the work has been dedicated to gamma spectroscopy measurements with different scintillator detectors (CsI:Tl, BGO and CeBr3) coupled to a Silicon Photo-Multiplier. Very important was the study of the non-linear response of the MPPC coupled to a CeBr3 scintillator.

Besides to the laboratory activity, I enjoyed the company of Pawel, Slawomir and Lukasz with whom I shared many delicious lunches in the canteen, where I tasted the famous Pierogi.          

I would like to thank FuseNet for having funded my research visit. Furthermore, a special thanks to Izabella Zychor who hosted me in her research group.


For a summary of Davide's work in Swierk, Poland, please click here to download a one-page PDF summarizing the results.