Expandable programmable integrated front-end for scintillator based photodetectors

Scintillator based photodetectors tend to increase the number of output signals in order to improve spatial and energy resolutions. AMIC architecture was introduced in previous works as an alternative to traditional charge division front-ends. This novel architecture not only allowed to reduce the number of signals to be acquired but also provided more information about the light distribution on the photodetector surface. Another key feature of this new approach lies in its ability to manage any number of inputs, thus offering an expandable solution for photodetectors with a large number of output signals. The underlying idea in AMIC architecture is to calculate the moments of the detected light distribution in an analog fashion. Due to the additive nature of the moment calculation, the operation can be carried out on a single device or split it into several devices, adding the partial results afterwards. A new integrated front-end device AMIC2GR has been developed which improves several features of the original AMIC architecture. A new preamplifier configuration extends the maximum capacitive load thus allowing compatibility with many types of photomultipliers including SiPM without loss of performance. In order to test the expandability of AMIC architecture using the new AMIC2GR, a front end with 4 devices has been developed. Measurements with a 256-SiPM array were made. Furthermore, a new calibration method (Edna Calibration Method) to compensate gain and detector module differences was developed and tested. AMIC2GR allows to calibrate each SiPM individually to obtain better spatial resolution and homogeneity.