Measurements of 6 MV x-rays. I. Primary radiation absorption in lead, steel and concrete.

Abstract

Abstract Narrow and broad-beam absorption coefficients were evaluated for lead, steel and concrete using the primary X-ray beam from a 6 MeV linear accelerator. For narrow beams the absorption coefficients in cm-1 are 0·50, 0·31, and 0·084 for lead, steel and concrete respectively, while the corresponding tenth-value thicknesses are 4·6, 7·5 and 27·4 cm respectively. For broad beams the absorption coefficients in cm-1 are 0·41, 0·23 and 0·066 for lead, steel and concrete respectively, while the corresponding tenth-value thicknesses are 5·7, 10·0 and 34·8 cm respectively. Measurements were made over six tenth-value thicknesses of lead and four to five for steel and concrete. Frequently, leakage and unwanted scatter are larger than the transmitted primary intensity by factors of 5 or greater. The methods of preferentially shielding and discriminating against these spurious components and the corrections for them are described. The attentuation curves, the experimental arrangements and the problems of measur...