Accession Number : ADA273822

Title :   Experimental Characterization of the AFIT Neutron Facility.

Descriptive Note : Master's thesis,

Corporate Author : AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH

Personal Author(s) : Lessard, Oscar J.

Report Date : SEP 1993

Pagination or Media Count : 114

Abstract : AFIT's Neutron Facility was characterized for room-return neutrons using a (252)Cf source and a Bonner sphere spectrometer with three experimental models, the shadow shield, the Eisenhauer, Schwartz, and Johnson (ESJ), and the polynomial models. The free-field fluences at one meter from the ESJ and polynomial models were compared to the equivalent value from the accepted experimental shadow shield model to determine the suitability of the models in the AFIT facility. The polynomial model behaved erratically, as expected, while the ESJ model compared to within 4.8% of the shadow shield model results for the four Bonner sphere calibration. The ratio of total fluence to free-field fluence at one meter for the ESJ model was then compared to the equivalent ratio obtained by a Monte Cario Neutron-Photon transport code (MCNP), an accepted computational model. The ESJ model compared to within 6.2% of the MCNP results. AFIT's fluence ratios were compared to equivalent ratios reported by three other neutron facilities which verified that AFIT's results fit previously published trends based on room volumes. The ESJ model appeared adequate for health physics applications and was chosen was chosen for calibration of the AFIT facility. Neutron Detector, Bonner Sphere, Neutron Dosimetry, Room Characterization.

Descriptors :   *FACILITIES, *NEUTRON DETECTORS, *NEUTRON SPECTRUM, *TEST FACILITIES, CALIBRATION, DETECTORS, DOSIMETRY, FREE FIELD, HEALTH PHYSICS, MODELS, NEUTRONS, PHOTONS, POLYNOMIALS, RATIOS, SHADOWS, SPECTROMETERS, SPHERES, TRANSPORT, VALUE, VOLUME, EXPERIMENTAL DESIGN, X RAYS, THESES.

Subject Categories : Nuclear Physics & Elementary Particle Physics
      Weapons Effects(biological)

Distribution Statement : APPROVED FOR PUBLIC RELEASE