Neutron Detection using Amorphous Boron-Carbide Hetero-Junction Diodes
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
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The high energy products of the 10Bn, alpha 7Li neutron capture reaction were explored as a means of thermal neutron detection in thin film amorphous boron carbide alpha--B5CHx 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 detectors negative response. A 1.47 MeV alpha 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 10 m of silicon however did generate transient currents 2 factors larger than steady-state reverse bias currents.
- Nuclear Instrumentation