A micro-strip germanium detector for position sensitive X-ray spectroscopy

• Main Authors: Protic, D., Stohlker, T., Beyer, H.F., Bojowald, J., Borchert, G., Gumberidze, A., Hamacher, A., Kozhuharov, C., Ma, X., Mohos, I.
• Format: Conference Proceeding
• Language: English
• Subjects: Energy resolution; Germanium; Paramagnetic resonance; Position sensitive particle detectors; Sensor arrays; Spectroscopy; Storage rings; Strips; X-ray detection; X-ray detectors
• ISSN: 1082-3654; 2577-0829
• DOI: 10.1109/NSSMIC.2000.949058

For the current X-ray spectroscopy program at the ESR storage ring (GSI-Darmstadt) a position sensitive germanium detector system has been completed. The position sensitive structure of the detector has been realized on an area of 47/spl times/23.4 mm/sup 2/ by an array of 200 strips (200 /spl mu/m wide and 23.4 mm long) separated by 35 /spl mu/m wide grooves etched through a boron implanted contact. The thickness of the detector inclusive of a 0.6 mm thick Li-diffused rear contact amounts to 4.1 mm. Each strip has been joined to a preamplifier placed outside the cryostat with printed leads inside the flexible Kapton foil. The energy resolution of the strips has been about 1.8 keV [FWHM] for 60 keV photons. Coincidences between neighbouring strips were measured whereby a time resolution of 70 ns [FWHM] was obtained. First preliminary results obtained with the detector mounted at the transmission X-ray spectrometer FOCAL demonstrated that an energy resolution better than 100 eV is achievable together with high detection efficiency. Along with a new kind of X-ray spectrometer this detector may play a key role for the next step of high precision X-ray experiments, aiming for a precise test of quantum electrodynamics in the heaviest one-electron systems such as a hydrogenlike uranium.