Construction and Testing of a Neutron and Gamma Spectrometry System Using Pulse Shape Discrimination with an Organic Scintillator

Author

Robert S. Pope

Date of Award

3-1993

Document Type

Thesis

Degree Name

Master of Science

Department

Department of Engineering Physics

First Advisor

Richard S. Hartley, PhD

Abstract

The goal of this thesis was to construct and test a neutron detector to measure the energy spectrum of 1 to 14-MeV neutrons in the presence of gammas. A spectrometer based on the process of pulse shape discrimination (PSD) was constructed, in which the scintillator NE-213 was used. The primary neutron/ gamma sources used were 78-mCi and 4.7-Ci ²³⁹PuBe sources, while 4.7-µCi and 97.6-µCi ²²Na gamma sources were used for energy calibration and additional testing of the detector. Proton recoil spectra and Compton electron spectra were unfolded with the neutron and gamma unfolding code FORIST to generate the incident neutron and gamma spectra, respectively. FORIST, which was written for a CDC computer, was modified to run on a VAX 6420. The experimental spectra were compared to those in the literature. The locations of the peaks in the ²³⁹PuBe spectrum agreed with the literature to within 8.3%, the ²³⁹PuBe gamma spectrum agreed to within 0.7%, while the ²²Na gamma spectrum agreed exactly. Uncertainties in the detection system and unfolding procedure are on the order of 5-10%. This thesis is intended to be a summary of the relevant literature and a user's guide to the PSD spectrometer.

AFIT Designator

AFIT-GNE-ENP-93M-6

DTIC Accession Number

ADA262550

Comments

The author's Vita page is omitted.

Recommended Citation

Pope, Robert S., "Construction and Testing of a Neutron and Gamma Spectrometry System Using Pulse Shape Discrimination with an Organic Scintillator" (1993). Theses and Dissertations. 7193.
https://scholar.afit.edu/etd/7193