A response function calculation for a dose-equivalent neutron dosimeter using superheated drops

Conference · Tue Jan 01 04:00:00 EST 1991 · Transactions of the American Nuclear Society; (United States)

OSTI ID:5916439

Wang, C K ^[1]

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1. Kansas State Univ., Manhattan (United States)

A neutron dosimeter using superheated drops in gel was invented by Apfel. The SDD-100 or BD-100, which uses Freon-12 (CF{sub 2}Cl{sub 2}) for the superheated drops, is most useful in neutron dosimetry because it was claimed that the neutron response function of such a dosimeter is nearly dose equivalent. An ideal dose-equivalent neutron dosimeter should be totally independent of the energies of incident neutrons. Lo and Apfel have performed calculations and experiments to study the neutron response functions for various types of superheated drops, including Freon-12. Both their calculational and the experimental results demonstrated the dose-equivalent-like response function for the Freon-12. The agreement between the calculational results and the experimental results is not satisfactory, however, especially for neutrons with energies < 100 keV. One important factor, which was not considered and may have contributed to the disagreement, is the neutron-slowing-down effect. That is, kilo-electron-volt neutrons, although not energetic enough to trigger bubbles in Freon-12, have a short mean-free-path (< 1 cm) and can easily slow down or thermalize in the gel matrix and then trigger bubbles in Freon-12 via a {sup 35}Cl(n,p){sup 35}S reaction. To consider the slowing-down effect in the dosimeter, a neutron transport calculation must be performed. This paper describes the set of Monte Carlo neutron transport calculations that were performed to calculate the response function for a bare SDD-100 surrounded with various thicknesses of polyethylene (CH{sub 2}).

• OSTI ID: 5916439
• Report Number(s): CONF-910603--
• Conference Information: Journal Name: Transactions of the American Nuclear Society; (United States) Journal Volume: 63
• Country of Publication: United States
• Language: English

Related Subjects

440101* -- Radiation Instrumentation-- General Detectors or Monitors &amp; Radiometric Instruments
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
663610 -- Neutron Physics-- (1992-)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
BUBBLES
COLLOIDS
COMPUTER CODES
CROSS SECTIONS
DISPERSIONS
DOSE EQUIVALENTS
DROPLETS
FREONS
FUNCTIONS
GELS
HALOGENATED ALIPHATIC HYDROCARBONS
HEATING
M CODES
MEASURING INSTRUMENTS
MONTE CARLO METHOD
NEUTRAL-PARTICLE TRANSPORT
NEUTRON DETECTORS
NEUTRON TRANSPORT
NUCLEAR DATA COLLECTIONS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC POLYMERS
PARTICLES
POLYETHYLENES
POLYMERS
POLYOLEFINS
RADIATION DETECTORS
RADIATION TRANSPORT
RESPONSE FUNCTIONS
SUPERHEATING