First experimental data from XH, a fine pitch germanium microstrip detector for energy dispersive EXAFS (EDE)

摘要

Extended X-Ray Absorption Fine Structure (EXAFS) is an experimental technique to determine the chemical structure of a sample by analysing modulations within its X-ray absorpton spectrum. The technique is commonly undertaken at synchrotron sources. A development to this technique, Energy Dispersive EXAFS (EDE), allows spectra to be collected extremely quickly enabling rapid chemical changes in a sample to be investigated. A number of the detection systems developed for this purpose have been reported previously. XSTRIP for High Energies (XH) is a new detector system developed between Daresbury Laboratory and Lawrence Berkeley National Laboratory (LBNL) specifically for EDE on 3rd generation synchrotrons. XH was commissioned to collect data at high energies (up to 40keV) with good efficiency, spatial performance and radiation damage tolerant. A key element of the system, a 1024 element germanium microstrip detector, fabricated using the amorphous-germanium (a-Ge) contact technology developed at LBNL allowing a strip pitch of 50μm to be achieved. The detector has been married to the UK designed X2CHIP readout technology which provides excellent system linearity (better than 0.1%) and ultra fast readout performance (100kHz frame rates). This paper will detail the construction of the detector and report on the first results from the system commissioning on beamlines 9.3 (at the Daresbury SRS) and ID24 (at the ESRF) where samples were studied at high energies.