Peak hold monolithic integrated circuit with built-in shaping amplifier for hard X-ray detector

A peak hold monolithic integrated circuit, a pulse shape discriminator (PSD), was designed and fabricated for a hard X-ray telescope of a well-type phoswich counter: Welcom-2. It will be loaded in an X-ray astronomical satellite, the Deep Universe Exploring Telescope (DUET). In order to fit the small area of the satellite, this PSD is manufactured by using a semi-custom bipolar junction transistor LSI. The circuit consists of two shaping amplifiers (100 and 500 ns), with peak hold circuits: a low level threshold comparator with a latch; a high level comparator; an auto reset circuit; and an input signal suppress circuit. Requirements for satellite use such as low power consumption under 200 mW/channel were satisfied. The circuit design and circuit analysis of the PSD have been carried out using the SPICE package. A quantitative measurement of the sample chips was carried out. The integral nonlinearity was measured to be less than 0.2% range, and the drop rate of the peak hold circuit was measured to be 0.2%/μs