Date of Award

3-22-2012

Document Type

Thesis

Degree Name

Master of Science

Department

Department of Engineering Physics

First Advisor

John W. McClory, PhD.

Abstract

The high energy products of the 10B(n,α)7Li neutron capture reaction were explored as a means of thermal neutron detection in thin film amorphous boron carbide (a--B5C:Hx) on n-type silicon hetero-junction diodes. Pulse height spectroscopy was conducted on the diodes while they were subjected to a moderated plutonium-beryllium (PuBe) source. Neutron capture could not be confirmed experimentally in any of the devices tested. Device modeling was performed to investigate the cause for the diode detector's negative response. A 1.47 MeV α particle produced transient current of 10-7 A and the induced was 4.7 times less than intrinsic noise charge of the preamplifier. Further investigation of the model emphasized the transient current magnitude was most dependent on the electric field strength. The possibility of direct-conversion hetero-junction neutron detectors was not experimentally confirmed, but simulations using only 10μm of silicon however did generate transient currents 2 factors larger than steady-state reverse bias currents.

AFIT Designator

AFIT-NUCL-ENP-12-M06

Included in

Physics Commons

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