A demonstrator prototype of multi-linear silicon drift detector as scatter detector for Compton imaging

Compton imaging is of interest in the fields of astrophysics, homeland security and nuclear medicine as it can provide high spatial resolution and detection efficiency even at high γ-ray energies. In this work, carried out under the auspices of a project of the Italian Space Agency, aimed to explore novel technologies for Compton architectures with high-efficiency and low background for the detection of γ-rays from space, we developed a demonstrator prototype of scatter detector based on a small-area Multi-Linear Silicon Drift Detector (MLSDD). MLSDDs are a recent evolution of silicon drift detectors in which the signal electrons generated by the interaction are confined within parallel drifting columns and transported towards pointlike anodes by the electrostatic field. The multi-linear transport mechanism accounts for a dramatic reduction in the number of channels required for true 2D position sensing (i.e. no. of channels equal to the square root of the pixels). Moreover it naturally allows the connection of the front-end electronics aside the detector chip thus simplifying the interconnection issue and it leads to readout times of only few microseconds and features a fast trigger signal (<;10ns) synchronous with the interaction. In this paper we show the main performance of the detection module in terms of position, energy and time resolution that asses its suitability as scatter detector in Compton imaging.