Self-triggered multi-linear silicon drift detectors

To be position sensitive, silicon drift detectors require a trigger signal ideally synchronous with the interaction time (i.e. the start of the electrons´ motion) as the interaction position along the drift coordinate is obtained from the measurement of the electrons´ drift time. In the case of photon interaction the trigger must be provided by the detector itself. One way to obtain a fast trigger signal exploits the induction signal given by the holes collected by the p strips close to the interaction point. We have designed and instrumented a multi-linear silicon drift detector especially intended to study the self-triggering technique for 2-D X-ray position sensing. Several measurements have been carried out to estimate the achievable performances. The measured position resolution along the drift coordinate is of the order of 10 ns with 10 keV photons leading to a position resolution of 30 μm rms at typical drift velocities. A comparable position resolution can be obtained on the lateral coordinate. By engineering the electron trajectory in the collection region, the anode capacitance can be minimized (<0.1pF) leading to excellent energy resolution even at room temperature.