is ws 0 5 in order to achieve the required absorption probability three such layers together with diodes at opposite sides of each layer are needed if the layer thicknesses used for the converter are smaller the probability ws for the detection of traces increases but more layers are needed to maintain the same absorption probability wa such a detector is shown in fig1 in a cross sectional representation shown are two diodes 4 each comprising n doped silicon with n layers 5 at opposite ends and depletion layers 3 with p face layers 2 at adjacent ends the converter layer 6 with a thickness of 16 u03bcm is disposed on one of the two diodes 4 the diodes are mounted at a distance in order to prevent damage to the converter layer 6 the metal pads for the p layer strips 2 are disposed on opposite sides and are freely accessible for wiring fig2 and 3 show the diode structure with the p and the metal pads 1 on one side in greater detail the n layer 5 on the opposite side also consists of strips which start out from underneath other pads these strips 5 extend in a direction normal to that in which the p layer strips 2 extend for the accurate positioning of the opposite wafers the wafers are provided with marks such as bores with the reverse bias voltage applied the depletion layer should have a thickness of about 15 u03bcm this is easily achievable with the usual doping of 10 15 cm 3 table 2 lists the most important properties of a detector which comprises two diodes with an intermediate converter layer its low detection probability for even subthermal.