Neutron/. gamma. dose separation by the multiple ion chamber technique

Thesis/Dissertation · Sat Jan 01 04:00:00 EST 1983

OSTI ID:6031125

Goetsch, S J

Mixed neutron/..gamma.. radiation dosimetry is more complex and less well understood than ..gamma.. dosimetry. Fundamental disagreements still exist over neutron/..gamma.. dose separation in phantom and in patients. Many mixed n/..gamma.. dosimetry systems rely on two dosimeters, one composed of a tissue-equivalent material and the other made from a non-hydrogeneous material. The paired chamber technique works well in fields of neutron radiation nearly identical in spectral composition to that in which the dosimeters were calibrated. However, this technique is drastically compromised in phantoms due to the degradation of the neutron spectrum. The three-dosimeter technique allows for the fall-off in neutron sensitivity of the two hydrogeneous dosimeters. Precise and physically meaningful results were obtained with this technique with a D-T source in air and in a phantom and with simultaneous D-T neutrons and /sup 60/Co ..gamma..-ray irradiation in air. The MORSE-CG coupled n/..gamma.. three dimensional Monte Carlo code was employed to calculate neutron and ..gamma.. doses in a water phantom. ..gamma.. doses calculated in the phantom with this code were generally lower than corresponding ion chamber measurements. This can be explained by the departure of irradiation conditions from ideal narrow-beam geometry.

• Research Organization: Wisconsin Univ., Madison (USA)
• OSTI ID: 6031125
• 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
CALCULATION METHODS
COMPARATIVE EVALUATIONS
DISPERSIONS
DOSES
DOSIMETRY
GAMMA DOSIMETRY
IONIZATION CHAMBERS
MEASURING INSTRUMENTS
MIXTURES
MOCKUP
MONTE CARLO METHOD
NEUTRON DOSIMETRY
PHANTOMS
RADIATION DETECTORS
RADIATION DOSES
STRUCTURAL MODELS