Dissertation/Thesis Abstract

Achieving Total Ionizing Radiation Dose Equivalency between NASA Jet Propulsion Laboratory's Cobalt-60 and Dynamitron Test Facilities
by Woo, Anastasia Robinson, M.S., California State University, Long Beach, 2019, 41; 22587864
Abstract (Summary)

This research presents efforts that the Radiation Effects group at NASA Jet Propulsion Laboratory (JPL) is making to explore the possibility of using its existing Dynamitron test facility to perform total ionizing dose (TID) tests. In order for the Dynamitron to be an acceptable facility to use for this intent, it must be able to produce equivalent results to JPL’s cobalt-60 test facility, which is where TID testing presently occurs. There is a difference in the radiation sources at the facilities, because the Dynamitron generates an electron beam, whereas the cobalt-60 cell generates gamma rays. This, in addition to general differences in test equipment, requires a different test method to be developed. We perform a comparison test between the two facilities using lidded and delidded IRFF130 MOSFETs at a dose rate of 18 rad(Si)/s by calculating equivalent values of energy and dose rate to use in the Dynamitron and taking parametric measurements following irradiation to view gate threshold voltage at equal dose levels. From this data, starting at the 10 krad(Si) dose point, we see voltage differences in lidded and delidded parts that were irradiated in the Dynamitron. Delidded parts showed a 0.2 V lower gate threshold voltage than lidded parts at 100 krad(Si) of dose. This difference is not seen in the parts irradiated in the cobalt-60 cell. Additionally, we see that all parts tested in the Dynamitron received an average of 0.2 V more damage than the parts tested in the cobalt-60 cell, which also became visible at the 10 krad(Si) dose point. Simulations of these tests are presently being explored to explain these differences before continuing with further comparison testing.

Indexing (document details)
Advisor: Jaikumar, Prashanth
Commitee: Kwon, Chuhee, Davies, Robert
School: California State University, Long Beach
Department: Physics and Astronomy
School Location: United States -- California
Source: MAI 81/4(E), Masters Abstracts International
Subjects: Physics
Publication Number: 22587864
ISBN: 9781687954268
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