Measurement of neutron-induced activation cross-sections using spallation source at JINR and neutronic validation of the Dubna code

A beam of 1 GeV proton coming from Dubna Nuclotron colliding with a lead target surrounded by 6 cm paraffin produces spallation neutrons. A Th-foil was kept on lead target (neutron spallation source) in a direct stream of neutrons for activation and other samples of 197Au, 209Bi, 59Co, 115In and 181Ta were irradiated by moderated beam of neutrons passing through 6 cm paraffin moderator. The gamma spectra of irradiated samples were analyzed using gamma spectrometry and DEIMOS software to measure the neutron cross-section. For this purpose neutron fluence at the positions of samples is also estimated using PREPRO software. The results of cross-sections for reactions 232Th(n, γ), 232Th(n, 2n), 197Au(n, γ), 197Au(n, α), 197Au(n, xn), 59Co(n, α), 59Co(n, xn), 181Ta(n, γ) and 181Ta(n, xn) are given in this paper. Neutronics validation of the Dubna Cascade Code is also done using cross-section data by other experiments

Investigation of defect production in iron on gamma irradiation using the positron Doppler broadening technique

51-55The parameters S and W corresponding to the positron Doppler broadening technique have been used to study displacement type defects produced in iron samples irradiated by various imparted doses of gamma ranging from 20 Gy to 2kGy. For the logistic support of the experimental observations, Monte Carlo simulation of displacements has also been performed. Of the increase of S parameter with dose up to a limit, it is revealed that vacancy type defects dominate. From both the experimental observations and the Monte Carlo study, it is inferred that on irradiation monovacancies are produced and under the given irradiation conditions there is negligible chance of the atom+atom collision cascade which may give rise to multiple type vacancies