New ideas for two dimensional position sensitive silicon drift detectors

In this paper we present two new ideas for drift detectors with two dimensional position resolution. The first idea is based on the regular drift detector, but has a slightly different design in order to deal with diffusion problems. The second idea embodies a completely new type of drift detector that uses drift time measurements for both dimensions. The design consists of concentric quadrilateral closed strips with a small collecting anode in the centre. At first electrons travel perpendicular to the strips until they reach a diagonal. Then they proceed along this diagonal until they are collected at the centre. Position resolution in two dimensions can be obtained when both the time the electrons need to reach the diagonal and the time they need to reach the centre are measured. The latter is obtained from the collecting anode, the former from a diagonal strip present at the back side of the detector. Compared to common 2D drift detectors this detector offers the advantage of a small amount of read out electronics. It also has the advantage of having just one small collecting anode with a very low capacitance, resulting in low noise and therefore in a good energy resolution