Silicon ultra fast cameras for electron and gamma sources in medical applications: a progress report

SUCIMA (Silicon Ultra fast Cameras for electron and gamma sources In Medical Applications) is a project approved by the European Commission within the Fifth Framework Programme, with the primary goal of developing a real time dosimeter based on direct detection of ionising particles in a position sensitive Silicon sensor. The main applications of this device are imaging of intravascular brachytherapy radioactive sources with-activities up to 3 GBq and real time monitoring of hadrontherapy beams. In order to perform a feasibility study, during the first two years a real time dosimeter has been engineered using Silicon microstrip detectors read out by an integrating dead-timeless front-end electronics. The prototypes have been qualified as relative dosimeter with respect to certified secondary standards; moreover, further measurements are on going in order to investigate the possibility to use the sensors as absolute dosimeters. Since the final device is supposed to provide a two dimensional image, two different Monolithic Active Pixel dosimeters have been designed and produced by the collaboration based on CMOS and Silicon On Insulator technologies. The main features of the two sensors are presented in this paper.