Peak detection circuit for sub-microsecond width pick-up signal from beam diagnostic pick-up detectors

Particle accelerator employs various beam diagnostic methods to accurately determine the behaviour and characteristics of particle beam. Beam position monitor (BPM) is one of the essential diagnostic devices that uses pick-up detectors to accurately monitor the position of charged particle beam. The pick-up signals from pick-up sensors of BPM gives the measure of beam position inside beam pipe. A 'Shoe-box' or 'Linear-cut' BPM is capacitive type which generates a differentiated signal when a charged particle beam pulse passes through it. The peak value of this differentiated signal indicates the proximity of beam pulse to detector plate. We have developed a peak detector circuit using commercially available ICs and components to measure electron beam position in linear accelerator at RRCAT. The circuit is able to hold the peak of signal as narrow as 0.5 µs. A test setup was developed to simulate electron beam through BPM by stretched-wire method and the generated pick up signal was processed. This paper describes the circuit scheme and set up description in detail. (author)