A novel multicell silicon drift detector module for X-ray spectroscopy andimaging applications

A novel 61-cell silicon drift detector module is proposed for high-counting rates and high-resolution X-ray spectroscopy and imaging applications at e nergies up to about 30 keV. Its hexagonal geometry with sloped sidewalls al lows a buckyball arrangement. Up to 1860 cells of an active area of 5 mm(2) each can be reached at an average distance to the specimen of only 4.3 cm. An optimized electrical connection concept offers a vertical integration o f It sensor array and signal processing electronics. Worst-case crosstalk o f 0.3% (-50 dB) and signal loss of 7% (-24 dB) were derived from electrical field analysis. A sandwich of metal foils between X-ray sensor and electro nics reduces the dose of radiation at the electronics by more than eight or ders of magnitude. Module-induced background fluorescence reaches its maxim um at an incident energy of 13 keV, but remains below 10(-4) of the incomin g photon Bur at all energies. Three-dimensional (3-D) simulations on therma l module behavior show that the use of graphite as housing material allows an operation with spatial inhomogenities of <1 <degrees>C on the sensor's a ctive area. Empirically, we found that the difference between the temperatu res of the sensor and the heat sink depends linearly on the power dissipate d by the electronics and sensor chip. The corresponding thermal resistances are 4.3 and 0.8 K/W.