Z-DEPENDENCE OF PAIR CROSS-SECTION IN THE ENERGY REGION 1 TO 2 Mev

Journal Article · Sat Jun 01 04:00:00 EDT 1963 · Indian Journal of Pure and Applied Physics (India)

OSTI ID:4713631

Rao, J R; Lakshminarayana, V; Swami, J

Absolute pair cross sections in copper, zirconium, rhodium, tin, tantalum, platinum, gold, and lead for gamma rays in the energy region 1 to 2 Mev are determined with a coincidence scintillation spectrometer, using intense sources of scandium-46, cobalt-60, europiumpair cross sections ( sigma ) show progressively increasing deviation from Bethe-Heitler values ( sigma /sub BH/) towards lower energies, according to expectation. In the case of lead, the experimental value obtained with antimony-124 source agrees with the interpolated value from J. C. Jaeger and H. R. Hulme's exact data at 3 mc/sup 2/ and 5.2 mc/ sup 2/. The extrapolated values from Jaeger and Hulme's data are found to be higher than the experimental values in lead obtained with europium-(152 + 154), cobalt-60, and scandium-46 sources. This discrepancy is attributed to the error involved in the process of extrapolation. The values of pair cross-sections in all the elements obtained in the study are found to show general agreement with previous results wherever such comparison could be made. The Z-dependence of pair cross section in the energy region 1.33--2.00 Mev could be represented by an equation of the type sigma = sigma /sub BH/(1 + dZ/sup 2/) with the deviation parameter d progressively increasing in value towards the low energy limit. However, at 1.119 Mev, the experimental data could be fitted in a modified Z - dependence formula. (auth)

• Research Organization: Andhra Univ., Waltair, India
• NSA Number: NSA-17-028275
• OSTI ID: 4713631
• Journal Information: Indian Journal of Pure and Applied Physics (India), Journal Name: Indian Journal of Pure and Applied Physics (India) Vol. Vol: 1: No. 6; ISSN IJOPA
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

BETHE-HEITLER THEORY
BREMSSTRAHLUNG
ENERGY RANGE
PAIR PRODUCTION
PHYSICS