NEUTRON DETECTION USING GADOLINIUM-BASED DIODES IBD

Sinopse

P-n heterojunction diodes consisting of a thin n-type layer of Gd?O? deposited on both p-type Si and p-type 4H SiC substrates were explored as possible solid-state neutron detectors. 79 keV internal conversion electrons from the de-excitation of the meta-stable Gd-158 nucleus can create ionization in the depletion region of the reverse-biased diodes resulting in a detectable signal. The diodes were modeled with Davinci software to determine the feasibility of signal detection above the reverse-bias leakage current. A CASINO simulation showed that less than one percent of the internal conversion electrons deposit their full energy within the achievable depletion region. After depositing contacts on samples prepared at the University of Nebraska, Lincoln, the diodes were exposed to thermal neutron fluxes of approximately 10³ n/cm² s in the AFIT Standard Graphite Pile and 10? n/cm² s in the thermal column of the Ohio State University Research Reactor. Pulse height spectra collected during irradiations at various reverse bias voltages ranging from - 0.5 V to -5.0 V revealed no discernable neutron induced features. Oscilloscope traces captured during the high thermal neutron flux irradiations show pulses, however, no evidence exists to attribute these pulses to neutron interactions.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.