Microcomputer-controlled pulse generator for an electron spin-echo spectrometer

Abstract

A simple and low-cost microcomputer-controlled pulse generator for an electron spinecho (ESE) spectrometer has been constructed. The generator is composed of a programmable clock pulse generator, a programmable delay generator, and a pulse sequencer. The clock pulse generator supplies trigger pulses to the delay generator with the period ranging from 1 μs to 99,990 s. The delay generator is composed of two commercial time delay modules (Evans Associates Model 4145-2) and an additional 2.5 ns increment delay generator, and supplies reference and delayed pulses to the pulse sequencer. The pulse sequencer generates a series of pulses for the formation of microwave pulses and the detection of ESE signals. Most of the control data for the pulse generator are supplied from a microcomputer (NEC PC-9801). The software for the microcomputer is designed to measure two- and three-pulse echo envelopes and longitudinal relaxation times with the minimum time resolution of 2.5 ns.