Energy dispersive semiconductor X-ray detector with improved silicon detector

An energy dispersive X-ray detector assembly has a detector element of a high-purity silicon substrate with a pair of electrodes, one on either side of the silicon substrate, to create an depletion layer in the silicon substrate when an electric field is created between the electrodes to enable the detection of X-rays. The silicon substrate has a resistivity of at least 10 k OMEGA xcm and a thickness in the incident direction of the X-rays of approximately 3 to 5 mm. A refrigerator system, such as a closed cycle gas circulation refrigerator, can be used to cool the detector element to enable the provision of a compact detector assembly.