Medium‐Energy Neutron Time‐of‐Flight Spectrometer

Abstract

A neutron time‐of‐flight spectrometer developed for the 1‐ to 20‐Mev region is described. The instrument makes use of the phase bunching of deuterons in the Michigan 42‐inch cyclotron and an external beam pulsing system to provide isolated bursts of neutrons of 4‐mμsec time duration. Flight times are measured with an improved version of the chronotron capable of a precision of ±3×10−10 sec. The energy spread for a 5‐meter flight path varies from 3.5% at 0.5 Mev to 10% at 20 Mev. The available neutron flux permits an improvement of at least a factor of three by lengthening the flight path. The Be9(d,n) thick target and the O16(d,n) thin target spectra are discussed.