OPTIMUM X-RAY YIELDS IN BETA-EXCITED X-RAY SOURCES

Technical Report · Fri Oct 31 04:00:00 EST 1958

OSTI ID:4316113

Kereiakes, J G; Krebs, A T

A conference version of AMRL-349. The experimental setup was so arranged that various thicknesses of target material could be studied with and without effect of backing materinal. The x raiations were detected by a NaI(Tl) crystal (1 1/2 in. diameter by 1 in. thick and having a 3 mil Al window to increase lowenergy counting effinciency) couplyed to a DuMont 6292 photomultinplier tube. The photomultiplier pulses were amplified and analyzed with a single-channel pulseheight analyzer. Optimum K x-ray yields were determined by placing various thicknesses of target foils between isotope (evaporated on Mylar films) and detector. Sn target foil thicknesses of about 55, 80, ad 80 mg/ cm/sup 2/ gave optimum K x-ray yields for Tl/sup 204/ (0.765 Mev), P/sup 32/ (1.701 Mev) and Sr/sup 90/ -Y/sup 90/(2.18 Mev) respectively, with no backing material. Ta target foil thicknesses of about 200 and 220 mg/cm/ sup 2/ gave optimum K x-ray yields for P/sup 32/ and Sr/sup 90/-Y/sup 90/, respectively. Optimum K x-ray yields found for Pb target foil thicknesses were 275 and 300 mg/cm/sup 2/ for P/sup 32/ and Sr/sup 90/-Y/sup 90/, respectively. In all cases, the optimum K x-ray yields were increased twofold by the addition of foil backing material of same thickness as that providing optimum K x-ray yields. Increase of foil backing material to a thickness that absorbed all betas further increased optimum K x-ray yield by about 12 to 18%. The findings show definitely that proper source configuration can greatly increase the efficiency of beta-excited x-ray sources and thus their possible use in the energy region where no suitable gamma-emitting isotopes presently exist. Their stability, economy, portability, and independence of power requirements are added advantages of these sources. Moreover, by source fabrication to allow interchanging of target materials and B-emitting isotopes, x-ray sources capable of giving various relatively monoenergetic x-ray energies are possible, in contrast to fixed gamma energies emitted by presently available isotopes. (auth)

• Research Organization: Army Medical Research Lab., Fort Knox, Ky.
• NSA Number: NSA-12-014840
• OSTI ID: 4316113
• Report Number(s): A/CONF.15/P/809
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

BETA PARTICLES
CRYSTALS
ECONOMICS
EFFICIENCY
ELECTRONIC EQUIPMENT
ENERGY
EXCITATION
FOILS
ISOTOPES
LEAD
MEASURED VALUES
PHOSPHORUS 32
PHOTOMULTIPLIERS
PHYSICS
RADIATION DETECTORS
RADIATION SOURCES
SODIUM IODIDES
STABILITY
STRONTIUM 90
TARGETS
THALLIUM 204
THICKNESS
TIN
X RADIATION
YTTRIUM 90