Date of Award

3-2020

Document Type

Thesis

Degree Name

Master of Science

Department

Department of Engineering Physics

First Advisor

James E. Bevins, PhD

Abstract

A stack of thin Gd, Ti, and Cu foils were irradiated with an 18 MeV proton beam at Lawrence-Berkeley National Laboratory's 88-Inch Cyclotron to investigate the 160Gd(p,n)160Tb nuclear reaction for nuclear forensics applications. This experiment will improve knowledge of 160Tb production rates, allowing 160Tb to be efficiently created in a foil stack consisting of other proton induced isotopes for forensics applications. A set of 15 measured cross sections between 4-18 MeV for 160Gd(p,n)160Tb were obtained using a stacked foil technique. The foil stack consisted of one stainless steel, one iron, fifteen gadolinium, nine copper, and eight titanium foils. The stainless steel and iron foils were used to radiograph thebeam spot size. Each Gd foil was encapsulated in Kapton tape prior to irradiation to minimize oxidation. The copper, 62Cu(p,n)62Zn and 65Cu(p,n)65Zn, and titanium, 48Ti(p,n)48V and natTi(p,x)46Sc, foils served as monitor foils to determine the proton uence throughout the stack. Variance minimization using a MCNP6.2 model was used to improve the reliability of the cross-section measurements by reducing the uncertainties in proton energy and uence by varying the density and incident beam energy within the uncertainty in the measurement of each. The measured cross section of the 160Gd(p,n)160Tb generally follows the shape predicted by TENDL-2019, but the cross sections obtained in this work indicate approximately a 20 increase in the maximum cross section. Additionally, other natGd(p,x) reactions were created through the irradiation, providing experimental measurements of 154Gd(p,2n)153Tb, 155Gd(p,)152Eu, 155Gd(p,2n)154Tb, 155Gd(p,n)155Tb, 156Gd(p,n)156Tb,157Gd(p,)154Eu, 160Gd(p,)157Eu, and 160Gd(p,d)159Gd reactions.

AFIT Designator

AFIT-ENP-MS-20-M-088

DTIC Accession Number

AD1101757

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