J. Bart Czirr

Capture-gated neutron spectrometry

The applications of a new inorganic scintillator, lithium gadolinium borate, to neutron dosimetry and spectroscopy, are described. A dosimeter using this material registers, in separate energy bins, thermal, epithermal and MeV neutrons. A spectrometer for MeV neutrons has a calculated energy resolution of 10% FWHM.

A neutron coincidence spectrometer

Abstract We have developed a spectrometer for MeV neutrons that relies upon total energy absorption to measure neutron energy. A coincidence signal is required from the capture of thermalized neutrons in Li-6 glass scintillators incorporated in the detector body. This dual signal from a single neutron provides a powerful means of discrimination against background events arising either from gamma rays or from ambient, low-energy neutrons. The spectrometer is particularly useful in situations in which the neutron source intensity is very low.

A compact neutron coincidence spectrometer, its measured response functions and potential applications

Abstract A one-liter “coincidence spectrometer” utilizing plastic scintillator and three 6 Li-glass plates has been calibrated at five neutron energies between 1.2 and 14.1 MeV, and the response functions are given. The features of this spectrometer, including the ability to operate with essentially no cross talk between multiple detectors, suggest several important potential applications, such as the neutron detector in π-d capture experiments to measure the nn scattering length, as well as other experiments involving multiple-neutron sources, spontaneous-fission detection, and dosimetry. The spectrometer is also compared with other current neutron spectrometer systems.

Gamma-ray sensitivity of 6Li-glass scintillators

Abstract The gamma-ray response of thin NE 905 6Li-glass scintillators is studied as a function of gamma-ray energy, scintillator thickness, and detector resolution. The probability for a gamma ray to simulate a neutron event is measured at three gamma-ray energies for three scintillator thicknesses. The feasibility of using coincidence information from electrons that diffuse out of the glass to reduce gamma-ray caused background is also studied.

High-efficiency fast-neutron detectors

Abstract Two high-efficiency detectors for fast neutrons are described. The first detects bursts of neutrons as well as single neutrons. The second is a neutron spectrometer with burst-mode capabilities. Both instruments require a signal from neutron energy loss in a moderating scintillator followed by a signal from neutron capture in 6Li. All potentially interesting events are recorded by a waveform digitizer for detailed analysis and background subtraction. Time dispersion of the capture signals makes possible an estimate of the number of incident neutrons in the burst. The spectrometer has been calibrated at four neutron energies from 1.2 to 14.1 MeV.

A moderating 6Li-glass neutron detector

Abstract A neutron detector with good detection efficiency in the neutron-energy range up to 1 MeV has been built using 2 mm thick 6 Li-glass plates immersed in a moderating liquid. The detector is compact, reasonably insensitive to gamma rays, and relatively fast.

Preliminary results from the BYU charged‐particle spectrometer

The detection system developed at Brigham Young University for charged‐particle studies is reported. (AIP)

High efficiency neutron and charged particle spectrometers

Two high‐efficiency neutron detectors, a neutron‐burst detector and a spectrometer was designed and built at Brigham Young University. (AIP)