Photon backscatter measurements of the polymethylmethacrylate phantom used in the US personnel dosimeter accreditation programs (NVLAP, DOELAP)

Conference · Fri Jun 01 04:00:00 EDT 1990

OSTI ID:6684706

Large, K K; Hooker, C D; McDonald, J C; Traub, R J

A study was conducted to determine the photon backscatter contribution to the response of thermoluminescent dosimeters (TLDs) that are irradiated on polymethylmethacrylate (PMMA) phantoms. Because the dose equivalent for photons is computed from the product of the exposure, the exposure to dose conversion factor, the backscatter factor, and the quality factor, it is necessary to know the backscatter factor to evaluate the dose equivalent. The backscatter factor was determined for the photon beams used in proficiency test irradiations. X-ray beams with effective energies ranging from approximately 15 to 120 keV were used along with Cs-137 and Co-60 gamma-rays. Thin LiF dosimeters were exposed in air and on the PMMA phantom, and the ratio of their responses per unit exposure were taken as a measure of the backscatter factor. These data were then compared with a previous set of Monte Carlo computer calculations, and were used to compute exposure to dose equivalent (C{sub x}) factors that were compared with the C{sub x} factors used for the DOELAP and NVLAP programs. The results of these measurements will be described in this presentation. 21 refs., 4 figs.

• Research Organization: Pacific Northwest Lab., Richland, WA (USA)
• Sponsoring Organization: DOE/EH
• DOE Contract Number: AC06-76RL01830
• OSTI ID: 6684706
• Report Number(s): PNL-SA-17693; CONF-900679--6; ON: DE90015302
• Country of Publication: United States
• Language: English

Related Subjects

440102 -- Radiation Instrumentation-- Radiation Dosemeters
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
61 RADIATION PROTECTION AND DOSIMETRY
655003* -- Medical Physics-- Dosimetry
ALKALI METAL ISOTOPES
BACKSCATTERING
BEAMS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CESIUM 137
CESIUM ISOTOPES
COBALT 60
COBALT ISOTOPES
DOSE EQUIVALENTS
DOSEMETERS
DOSIMETRY
ELECTROMAGNETIC RADIATION
ESTERS
EVALUATION
GAMMA RADIATION
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
IONIZING RADIATIONS
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
LUMINESCENT DOSEMETERS
MEASURING INSTRUMENTS
MINUTES LIVING RADIOISOTOPES
MOCKUP
MONTE CARLO METHOD
NUCLEI
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANIC POLYMERS
PERSONNEL DOSIMETRY
PHANTOMS
PHOTON BEAMS
PMMA
POLYACRYLATES
POLYMERS
POLYVINYLS
RADIATIONS
RADIOISOTOPES
SCATTERING
STRUCTURAL MODELS
TESTING
THERMOLUMINESCENT DOSEMETERS
YEARS LIVING RADIOISOT
YEARS LIVING RADIOISOTOPES