Current situation for exoelectron dosimeters of BeO ceramic in neutron dosimetry

Conference · Sat Jan 01 04:00:00 EST 1977

OSTI ID:7285473

Gammage, R B

Much of the early enthusiasm for using exoelectron dosimeters (ceramic BeO Thermalox 995) in neutron dosimetry was predicted on the belief that the response to fast neutrons, relative to gamma rays, was 0.18 to 0.28 on a R/sub ..gamma../ equiv/tissue rad n/sub f/ basis for neutron energies between 0.1 and 16 MeV. Pairs of BeO disks had to be used, one covered with a polyethylene radiator for producing recoil protons, and the other covered with Teflon. More recent studies indicated a considerably lower ratio of 0.11 for Health Physics Reactor Research fission neutrons. In the earlier work the BeO was coated with gold to enhance the surface conductivity during reading of the thermally stimulated exoelectron emission (TSEE). No metallic coating is now deemed to be necessary. Perhaps thermal neutron contamination of the fast neutron beams due to some thermalization within the hydrogenous radiator was sufficient to cause the high apparent fast neutron sensitivity via n, ..gamma.. reactions. Whatever the cause, however, the lower value of 0.11 has caused a marked subsidence of enthusiasm in this technique of fast neutron monitoring.

• Research Organization: Oak Ridge National Lab., Tenn. (USA)
• DOE Contract Number: W-7405-ENG-26
• OSTI ID: 7285473
• Report Number(s): CONF-770726-1
• Country of Publication: United States
• Language: English

Related Subjects

440102* -- Radiation Instrumentation-- Radiation Dosemeters
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
ALKALINE EARTH METAL COMPOUNDS
BERYLLIUM COMPOUNDS
BERYLLIUM OXIDES
CERAMICS
CHALCOGENIDES
DOSEMETERS
DOSIMETRY
EXOELECTRON DOSEMETERS
MEASURING INSTRUMENTS
NEUTRON DOSIMETRY
OXIDES
OXYGEN COMPOUNDS
SENSITIVITY