A detector for detecting ionising radiation comprising at least one detector arranged to be connected to a read-out arrangement for the reading-out and the evaluation of a signal from the detector, which detector comprises a carrier material and a layer (4) comprising an active detector material applied to the carrier material, which active detector material is arranged, in the event of its receiving incident ionising radiation (3) that is incident upon the said layer (4), to give rise to ionisation in the said active detector material in the said layer (4), where an electrical field is applied across the said layer (4), whereby the said ionisation gives rise to an electric current, which said read-out arrangement is arranged to detect such that it can in this way detect the said incident ionising radiation (3) . The invention is characterised in that the said active detector material in the said layer contains ZnO to such an extent that ionising radiation gives rise to a detectable electric current.