An automatic peltier effect based MPPC gain regulation for brain-PET

This work is part of a large project contributing in the design and development of medium field and high resolution Positron Emission Topographic (PET) scanners. The Multi Pixel Photon Counters (MPPCs) are an elementary part of PET scanners. They convert the scintillation energy, originated by the emitted gamma rays from patient's body, into electrical pulses. These pulses are later on conditioned and processed to locate the cancerous cells in the body of patient. The form of these pulses is very important in making a precise localization of the cancerous cells. MPPCs are very sensitive to the ambient temperature variations. Such variations affect the gain of MPPCs which is finally reflected as a reduction in the cancerous cells localization. In this framework a Peltier effect based approach is devised to minimize the ambient temperature variations effect on the performance of MPPCs. The proposed solution functionality is tested with an experimental setup. Results are presented, which assure a proper functionality of the suggested system.