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-ano de Silicon Drift Detectors, or other multi-element solid-state X-ray detect ion systems. The readout scheme has been conceived and developed for demand ing applications with synchrotron light sources, such as X-ray holography o r EXAFS experiments, where both high count-rates and high energy resolution s are required. The circuit is of time-variant nature, accepts randomly dis tributed events and features a finite-width (1.1 mu s) weight function, a l ow-level energy discrimination, a low power consumption (a few mW per chann el) and a full compatibility with monolithic integration in CMOS technology . Its impulse response has a staircase-like shape, but the implemented weig ht function (which is in general different from the impulse response in tim e-variant systems) is quasi trapezoidal. A first prototype of the circuit i s here described and the first experimental results are also reported.