Prototyping experience with Ge micro-strip sensors for EDXAS experiments

Abstract Energy dispersive X-ray spectrometers provide a method for the fast data acquisition of X-ray absorption spectra. The intensity of the spectral components of a polychromatic beam is detected simultaneously after being dispersed in space, and being transmitted by an experimental sample. The cryogenic detector system called XH deploys a germanium micro-strip sensor to perform such measurements. Here, the geometrical position of each strip is correlated to a specific spectral component of the dispersed beam. The prototyping experience reported in this work is related to the upgrade of the cryostat unit of the XH detector system. This upgrade was carried out in collaboration with beam-line ID24 at the European Synchrotron Radiation Facility (ESRF). Two 90 mm wafers of p-type high purity germanium were manufactured. Wafers contained test structures and micro-strip sensors made of 1024 strips with 50 μ m pitch. Electrical and in-beam tests were performed to verify the performance of this technology. The measurements included capacitance–voltage characteristics; stress-tests like temperature cycling testing and burn-in tests; leakage current as a function of sensor temperature; charge-collection as a function of time; a test-run of a pump and probe experiment. Results are reported below showing that this sensor technology survived the extensive thermal and electrical stress-tests, and that it was able to measure the physical variations created by a laser shock on a sample of Fe–10%wtNi.