A novel multicell silicon drift detector module for X-rayspectroscopy and imaging 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 energies up to about 30 keV. Its hexagonal geometry with sloped sidewalls allows a buckyball arrangement. Up to 1860 cells of an active area of 5 mm² each can he reached at an average distance to the specimen of only 4.3 cm. An optimized electrical connection concept offers a vertical integration of a sensor array and signal processing electronics. Worst-case crosstalk of 0.3% (-50 dB) and signal loss of 7% (-24 dB) were derived from electrical field analysis. A sandwich of metal foils between the X-ray sensor and electronics reduces the dose of radiation at the electronics by more than eight orders of magnitude. Module-induced background fluorescence reaches its maximum at an incident energy of 13 keV, but remains below 10^-4 of the incoming photon flux at all energies. Three-dimensional (3-D) simulations on thermal module behavior show that the use of graphite as housing material allows an operation with spatial inhomogeneities of <1°C on the sensor's active area. Empirically, we found that the difference between the temperatures of the sensor and the heat sink depends linearly on the power dissipated by the electronics and sensor chip. The corresponding thermal resistances are 4.3 and 0.8 K/W