High resolution imaging silicon-x-ray spectrometers

Abstract

X-rays in the energy bandwidth of 100eV up to 30keV can be nicely detected with modern silicon detectors with integrated readout electronics. Matrix-type silicon detectors exhibit a position resolution of the order of microns, a time resolution in the microsecond range and a Fano limited energy resolution. All properties can be measured simultaneously with one single device. The properties of silicon drift detectors (SDD) will be derived from basic physical principles and compared with measurements. Fully depleted charge coupled devices (pnCCDs) have been used in space observatories and on ground. Monolythic systems with sensitive areas of 1-36 cm 2 are currently operated with pixel sizes from 30 to 150 μm. Controlled drift detectors, a combination of a SDD and a CCD was operated with up to 100 000 pictures per second. X-ray active pixel sensors (APS) on the basis of the detector-amplifier structure DEPFET have been fabricated and tested recently with great success. The achieved energy resolution at room temperature was better than 150 eV (FWHM). They are foreseen for ESA's future X-ray mission XEUS. At the same time thinned and faster DEPFET arrays are being developed for linear collider applications. The fabrication of the detectors and the electronics is made in research labs for optimum flexibility during research and with the possibility of commercial transfers to institutions and companies.