Radiation transmission and scattering for medical linacs producing x rays of 6 and 15 MV: comparison of calculations with measurements.
We present comparisons of calculated and measured dose equivalent rates outside the shielding and in the entry mazes of 2 medical linac facilities producing x rays at 6 and 15 MV. Calculations were made using the NCRP recommendations for estimating transmission of radiation through a shielding wall and scattering of radiation in a maze. We found that, for walls made of high-density concrete, the x-ray dose rate outside the shield was estimated within 50% if transmission factors measured in the appropriate high-density concrete were used. The dose rate was overestimated by a factor of 2-4 when transmission factors for normal concrete were scaled using a density ratio. Dose equivalent rates calculated for x rays and neutrons in the entry mazes agreed within a factor of 2 with the measurements.
D009502:Neutrons; D010315:Particle Accelerators; D011829:Radiation Dosage; D011834:Radiation Monitoring; D011835:Radiation Protection; D011882:Radiotherapy, High-Energy / Q000295:instrumentation*; D012542:Scattering, Radiation