A Digital Readout Scheme for Arrays of Microcalorimeter X-Ray Detectors

Abstract While the performance of single-pixel microcalorimeter x-ray detectors has been shown to be very useful for microanalysis1, arrays of microcalorimeters will have a further impact on energy dispersive spectroscopy (EDS) by providing higher total count rates and larger effective areas. We are developing a system with a 32x32 pixel array with a total area of 40 mm2 and with a total count rate between 105 and 106 s-1. One of the challenges in constructing an array-based system will be the readout electronics. In a typical microcalorimeter EDS setup, shown in Fig. 1, the microcalorimeter is readout using a cryogenic amplifier (SQUID system) and analog feedback electronics to control the SQUID. The signal from the room-temperature SQUID electronics is either attached to a spectroscopy-grade shaping amplifier and MCA for real-time analog signal processing or attached to a digitizer for optimal pulse processing.