Accession Number : ADA332697

Title :   Development of an Improved Direct Neutron Sensor

Descriptive Note : Technical rept. 16 Sep 90-27 Sep 96

Corporate Author : KEMP CORP KNOXVILLE TN

Personal Author(s) : LeVert, Francis E.

PDF Url : ADA332697

Report Date : NOV 1997

Pagination or Media Count : 68

Abstract : The feasibility study of the use of conductive polymers to design and assemble a neutron monitor sensitive to fast and thermal neutrons has been completed. Polyacetylene, polypyrrole and polythiophene conductive polymers with conductivities that range from 10(exp -4) (omega-cm)-1 down to 10(exp -11) (omega-cm)-1 were used in this investigation. The sensors were exposed to neutrons from an Am-Be sealed source with an average energy of 2.5 MeV and a 14 MeV neutron generator. The conductive polymer film was inserted between two structural elements consisting of quartz plates of polyethylene prisms with electrode structures formed with conductive paints or other conductive materials interposed between the polymer structural elements. The polyacetylene film used in the investigation exhibited the most consistent results revealing a sensitivity of tilde 10(exp -15) coulombs/neutron/sq cm. A polyacetylene based directionally sensitive detector with parallel plate geometry exposed to 14 MeV neutrons revealed a two to one front to back directional discrimination capacity. In tests where the sensors that were designed with isotropic sensitivity were exposed to 100 microcurie Am-Be source, thick BF4 doped and undoped sensors revealed a minimum sensitivity of tilde 400 n/sq cm (nv-thermal), when referenced to a calibrated Boron lined proportional counter with a minimum sensitivity of 12 n/sq cm (nv-thermal).

Descriptors :   *PYRROLES, *ACETYLENE, *THIOPHENES, *NEUTRON DETECTORS, CONDUCTIVITY, FEASIBILITY STUDIES, ELECTRODES, ISOTROPISM, POLYMERIC FILMS, FAST NEUTRONS, POLYETHYLENE, THERMAL NEUTRONS.

Subject Categories : Organic Chemistry
      Nuclear Instrumentation

Distribution Statement : APPROVED FOR PUBLIC RELEASE