High resolution X-ray spectroscopy close to room temperature

Originally designed as position sensitive detectors for particle tracking, silicon drift detectors are nowadays used for high count rate X-ray spectroscopy, operating close to room temperature. Due to their low capacitance read-node concept, they belong to the fastest high resolution detector systems. They have opened a new spectrum of experiments in the wide field of X-ray spectroscopy: fluorescent analysis, di®ractometry, material analysis, synchrotron experiments like X-ray holography and element imaging in scanning electron microscopes. The fact, that the detector system can be used at room temperature with good spectroscopic performance, and at -10±C with excellent energy resolution, avoiding liquid nitrogen for cooling and high quality vacuum, guarantees a large variety of new applications, independent of the laboratory environment. A brief description of the device principles is followed by basics on low noise ampli cation. The performance figures of a complete detector system are presented as well as some dedicated applications already realized. The use in a surface mapping instrument will be described as well as a recently operated "mini-spectrometer" for the analysis of works of art. For the European X-ray Multi-Mirror mission (XMM) and the German X-ray satellite ABRIXAS fully depleted pn-CCDs have been fabricated, enabling high speed, low noise, position resolving X-ray spectroscopy. The detector was designed and fabricated with a homogeneously sensitive area of 36 cm2 . At -70±C it has a noise of 4 erms, with a readout time of the total focal plane array of 4 ms. The maximum count rate for single photon counting was 10 5 cps under flat field conditions. In the integration mode more than 109 cps can be detected at 6 keV. Its position resolution is in the order of 100 1m. The quantum e±ciency is higher than 90% ranging from Carbon K X-rays (277 eV) up to 10 keV.