Doctoral Dissertations

Date of Award

5-2014

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Nuclear Engineering

Major Professor

Lawrence H. Heilbronn

Committee Members

Lawrence W. Townsend, Laurence F. Miller, Robert Grzywacz

Abstract

As missions in space become longer, the dangers posed to astronauts become increasingly prevalent. One of the many dangers is an increasing radiation dose caused by the unique radiation present in space called Galactic Cosmic Radiation (GCR). The complexity of GCR usually requires the use of transport codes when testing new materials for use in space. Some of these codes use the coalescence model to provide fragmentation light-ion production cross section data when no tabulated data is available. The accuracy of this model depends on the availability of experimental proton, neutron, and light-ion production cross section data. Since there is little experimental data that is applicable to the coalescence model, the validity of the model over the wide range of energies and interactions that are present in GCR is uncertain.

Described in this thesis is an experiment that provides the means of measuring double differential cross section data for protons, deuterons, and tritons for 39 different projectile/target systems with projectile energies ranging from 250 to 600 AMeV. Eight of these systems also provide cross section data for 3He and 4He. The cross sections were provided at energies ranging between 50 and 300 AMeV at the angles of 5, 10, 20, 30, 40, 60, and 80 degrees off the beam axis. As of this paper, no other reports or articles have included such an extensive set of both neutron and proton, as well as light-ion cross sections.

The cross sections obtained from this experiment were used to calculate coalescence radii for each measured angle for each system. Coalescence radii were also determined over all angles to provide system-wide radii. The calculated radii varied from system to system, and ranged from 60 to 200 MeV/c. The radii tended to be larger with lower mass systems (either the projectile or target), and fell as the mass of the systems increased.

Download
Files over 3MB may be slow to open. For best results, right-click and select "save as..."

Share

COinS