A Preamplifier-Shaper-Stretcher Integrated Circuit System for Use with Germanium Strip Detectors
OAK RIDGE NATIONAL LAB TN
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A 16-channel Integrated Circuit readout electronics chip is being developed for use with a germanium strip detector. Such a system will provide superior energy resolution with 2- dimensional imaging in a single instrument that can be used for X-ray imaging and nuclear line gamma-ray spectroscopy. As part of the total ASIC development, prototype ICs of a typical channel have been designed, fabricated and tested. These integrated circuits include a low-noise, variable gain, preamplifier circuit that can detect both positive and negative going input charges, a 4-pole pulse shaper with variable peaking times and a stretcher circuit that can do a peak detect and hold for the different peaking times. The integrated circuits are fabricated in a 1.2 micron n-well CMOS process. The noise performance for this system was measured to be 185erms 14epF for a 2 microsecs peaking time and gain at approx. 200mVfC. Linearity measurements in both inverting and non-inverting modes of operation were approximately -1. Peaking times from 0.5 microseconds to 8 microseconds and gain adjustments to get up to 400mVfC per channel were done through digital switching.
- Inorganic Chemistry
- Electrical and Electronic Equipment