S. S. Rattan

A method for the simultaneous estimation of228Th and229Th

A simple method is reported in this paper to estimate229Th in the presence of228Th. The total activity of229Th and228Th was determined by following the alpha activity growth (using a liquid scintillation counter and proportional counter) of purified thorium samples. The activity ratio of229Th/228Th was determined by alpha spectrometry. From the initial total activity and ratio, disintegration rates of229Th and228Th were calculated. The values obtained for the activities have a precision better than ±2%.

Fission in the reaction of12C with209Bi at 73.4 and 84.2 MeV

Fission product yield studies in the reaction of 73,4 and 84.2 MeV12C with209Bi have been carried out using gamma-ray spectrometry. The cross sections for the production of fission products have been determined. The yield distribution of fission products is found to be symmetric and broad with FWHM around 25 mass units and peak near mass 107.7 and 107.0. The average number of neutrons emitted per fission have been found to be around 5.5 at 73.4 MeV and 7.1 at 84.2 MeV, respectively.

Alpha Particle Induced Reactions on 27Al at 55.2 and 58.2 MeV

The alpha particle induced reactions on 2 Al have been studied using gamma ray spectrometry. The cross sections for the formation of 7 Be, 2 Na, 2 Na, 2 Mg, 2 Mg, A1 and A1 in the alpha particle induced reaction on A1 with alpha particles of energy 55.2 MeV and 58.2 MeV have been determined. The results are discussed in terms of increasing projectile energy and multi nucleon as well as cluster emission from the excited nucleus. o(-BEAM 25 4jjm Al

Excitation Functions for Multi-Nucleon Emission in Helium Ion Reactions with 197Au

Excitation functions for the production of heavy residues through He reactions on Au targets have been measured in the incident energy range of 35 — 50 MeV which probes and extends the lower limits of the excitation functions for cluster and multi-nucleon emission. The older cross-section values that partially cover this energy region have been re-evaluated using more recent decay scheme data and compared with the present measurements. Interference from secondary neutrons in the cross-sections of interest were investigated.