AN ULTRA-LOW NOISE MULTICHANNEL INTEGRATED READOUT FOR X-RAYS MULTI-DETECTORS

The characteristics of a very general readout for X-rays multi-detecto rs are presented. This readout is composed of two integrated circuits of ten identical channels. The analog circuit provides an input equiva lent noise charge of less than 70 e rms at room temperature that allow s the elimination of scattered X-rays and other background in fluoresc ence excitation mode experiments, for photons energy higher than 10 ke V interacting with a silicon detector. The typical full width at half maximum of the output pulse is 2.2 mus and the gain is 125 mV/fC for a total dc power consumption of about 35 mW/channel. The digital circui t is composed of a high accurate window comparator followed by a 16 bi ts counter and by a 16 bits buffer. It can be directly read by a compu ter through a parallel bus without interrupting the photons counting. The whole system provides a significant improvement in X-rays detector readout and will open new opportunities in experiments which require one or several of these three performances: high counting rate, high s patial resolution and high energy resolution.