Accession Number:

ADA209307

Title:

Flux and Spectrum of Neutrons Generated from 25 Mv Medical X-Ray Therapy Machine

Descriptive Note:

Master's thesis

Corporate Author:

AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING

Personal Author(s):

Report Date:

1989-05-01

Pagination or Media Count:

121.0

Abstract:

A procedure was developed for the routine monitoring of neutron dose absorbed by patients receiving x-ray therapy with high-energy electron accelerators. The source of the neutrons was photonuclear reactions. The detection system used to measure them is described. Three methods are described and compared for measuring the neutron flux by activation of thin gold foils. These included the cadmium-difference method for thermal flux determination, a cadmium-clad polyethylene moderator known to have a relatively flat response to neutrons in the energy range of interest, and a Bonner sphere set for measuring flux and the neutron energy spectrum. Results in an actual hospital installation using a BBC 45-MeV betatron revealed whole body neutron dose rates of approximately 1.5 mrem per photon rad. Two beta counting systems were calibrated so that routine measurements of neutron dose could be estimated from foil activation data and monitored for unexpected changes. Keywords Military theses Irradiation Radiology Xrays Dosimetry.

Subject Categories:

  • Medicine and Medical Research
  • Radiobiology
  • Physical Chemistry

Distribution Statement:

APPROVED FOR PUBLIC RELEASE