A monolithic implementation of a switched-current "wheel" amplifier for multi-channel Silicon Drift Detectors

In this paper we present a new VLSI shaper amplifier suitable for multi-anode Silicon Drift Detectors, or other multi-element solid-state X-ray detection systems. The readout scheme has been conceived and developed for demanding applications with synchrotron light sources, such as X-ray holography or EXAFS experiments, where both high count-rates and high energy resolutions are required. The circuit is of time-variant nature, accepts randomly distributed events and features a finite-width (1.1 /spl mu/s) weight function, a low-level energy discrimination, a low power consumption (a few mW per channel) and a full compatibility with monolithic integration in CMOS technology. Its impulse response has a staircase-like shape, but the implemented weight function (which is in general different from the impulse response in time-variant systems) is quasi trapezoidal. A first prototype of the circuit is here described and the first experimental results are also reported.