Multi-channel implementation of ROTOR amplifier for the readout of silicon drift detectors arrays

In this paper we present a multi-channel VLSI implementation of ROTOR, a time-variant-parameters shaping amplifier designed for the readout of high-rate asynchronous signals from multi-element solid-state X-ray detection systems. In particular, ROTOR was optimised for high-rate X-ray spectroscopy with multi-element Semiconductor Drift Detectors in applications using synchrotron light sources, such as X-ray holography or EXAFS experiments. A 30 channels circuit has been implemented in the 1 μm/5 V JFET/CMOS technology of the Fraunhofer-Institut, Duisburg (Germany). Each analog channel features a trapezoidal weighting function, 1.6 μm wide, obtained by means of a switched-current technique. A digital section, directly integrated on the ROTOR chip, allows the timing and control of all the analog switches of the amplifiers as required for the circuit functionality, without the need of external signals. The results obtained in the experimental characterization of the circuit and in spectroscopy measurements by using Silicon Drift Detectors are presented.