Neutron response of a new albedo-neutron dosimeter

Conference · Sun Jan 01 04:00:00 EST 1978

OSTI ID:5001044

Blackstock, A W; Cortez, J R; Littlejohn, G J; Storm, E

The Los Alamos Scientific Laboratory is converting from a film badge to a badge containing thermoluminescent dosimeters (TLD's). The new dosimeter consists of a plastic badge holding an aluminum card which contains three TLD-700 and one TLD-600 Harshaw LiF chips. In the albedo-neutron portion of the badge, based on Hankins' design, the TLD-600 and one TLD-700 chips are shielded from thermal neutrons by 0.026-inch-thick cadmium. From the difference in readings of these two TLD's, the neutron dose is estimated. There is also a detachable holder for NTA film if needed to cover the neutron energy range not covered by the albedo-neutron badge. The neutron energy response of the new badge was measured, using monoenergetic sources over the range from 0.1 to 14 MeV and is compared with a calculated response over this range. Since NTA film cannot detect proton recoils from neutrons with energies less than 0.7 MeV, a primary advantage of the TLD albedo-neutron badge is its ability to record neutrons down to the cadmium cutoff. However, a major disadvantage is its sharp decrease in sensitivity with increasing energy. Data are given showing this. Using a BF/sub 3/ detector inside 9-inch and 3-inch polyethylene spheres containing cadmium, Hankins developed a method for applying energy calibration factors to the albedo-neutron TLD badge readings. This method is based on two premises: first, that the response in rem of the 9-inch sphere is independent of energy and second, that the response of the 3-inch sphere is similar to that of the TLD albedo-neutron badge. Measurements to test the validity of these premises are reported. The method requires initial 9-inch to 3-inch sphere ratios to be measured in each area where neutrons are encountered and periodic checks to detect changes which may occur.

• Research Organization: Los Alamos Scientific Lab., N.Mex. (USA)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 5001044
• Report Number(s): LA-UR-78-40; CONF-780110-8
• Country of Publication: United States
• Language: English

Related Subjects

440102* -- Radiation Instrumentation-- Radiation Dosemeters
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
ALBEDO-NEUTRON DOSEMETERS
CADMIUM
CALIBRATION
DESIGN
DOSEMETERS
DOSIMETRY
ELEMENTS
ENERGY DEPENDENCE
LUMINESCENT DOSEMETERS
MEASURING INSTRUMENTS
METALS
NEUTRON DOSIMETRY
PERFORMANCE
PERSONNEL DOSIMETRY
SENSITIVITY
THERMOLUMINESCENT DOSEMETERS