A CMOS ANALOG-DIGITAL INTEGRATED-CIRCUIT FOR CHARGED-PARTICLE SPECTRUM MEASUREMENTS

We present a first prototype for a CMOS analog-digital integrated circ uit suitable for energy spectra measurements of space plasmas, using s olid state detectors. Our single chip system includes a charge preampl ifier followed by a pulse shaper, an energy discrimination block and a n accumulation stage. The particle energy spectrum is measured in 10 c hannels through a novel non-linear flash A/D converter and is stored i n equinumber 11-bit registers, which can then be selectively addressed , read out, and reset. The overall noise performance with detector cap acitance of 50 pf is equivalent to approximately 7000 electrons. The p ower dissipation is approximately 120 mW. The complete system can reso lve particle counting rates as high as 1.5 x 10(-5) counts/sec, and as high as 10(6) counts/sec in the pulse height analysis-accumulation mo de. The small size and low power dissipation makes such an application attractive for space experiments and portable nuclear instrumentation .