Accession Number : AD0806436

Title :   OPTIMUM X-RAY YIELDS IN BETA-EXCITED X-RAY SOURCES,

Corporate Author : ARMY MEDICAL RESEARCH LAB FORT KNOX KY

Personal Author(s) : Kereiakes, J. G. ; Weir, O. E. ; Krebs, A. T.

Report Date : 27 JUL 1958

Pagination or Media Count : 12

Abstract : An investigation was conducted to systematically investigate the influence of source physical conditions on the characteristic X-ray yield in beta-excited X-ray sources. The K X-ray yield excited by beta-particles in various target materials increased with increasing target thickness up to a maximum, after which the yield decreased because of X-ray absorption by target material. Optimum K X-ray yields were noted for P32 beta-particles at target thicknesses of about 77, 180, and 280 mg/sq cm, respectively, for Sn, Ta, and Pb targets. Sn, Ta, and Pb target thicknesses of about 80,205, and 310 mg/sq cm, respectively, were found to give optimum K X-ray yields for Sr90 - Y90 betas. The K X-ray intensities were increased by from 110 to 160 percent by the addition of source backing of same thickness as that providing maximum X-ray yields. Increase of backing to a thickness greater than that required to absorb maximum beta energies further increased maximum X-ray intensities from 25 to 50 per cent. Increased K X-ray yield efficiency extends the use of these sources to certain practical applications in low energy region (below 100 kev) where no suitable gamma-emitting isotopes presently exist. It is recommended that source physical conditions presented in this study be used, along with image intensifying systems, to extend the possible use of beta-excited X-ray sources to certain practical applications where increased X-ray intensity is desired.

Descriptors :   (*X RAY TUBES, SECONDARY EMISSION), BETA PARTICLES, METAL PLATES, TARGETS, TIN, TANTALUM, LEAD(METAL), EMISSIVITY, INTENSITY, THICKNESS, GAMMA RAYS, STRONTIUM, YTTRIUM, THALLIUM, PHOSPHORUS, MEDICAL EQUIPMENT.

Subject Categories : Medical Facilities, Equipment and Supplies
      Nuclear Physics & Elementary Particle Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE