Application of medium energy plasma focus device in study of radioisotopes

摘要

Pulsed neutrons generated in a plasma focus device are used for the thermal neutron activation analysis (TNAA) of selected three elements having widely different half-lives varying from a few seconds to a few days [Dysprosium (Dy), Manganese (Mn) and Gold (Au)]. Neutron pulse having strength of (1.2 +/- 0.3) x 10(9) neutrons/pulse with a pulse width of 46 +/- 5 ns is produced by "MEPF-12" device operated at a filling gas (deuterium + 0.5% krypton) pressure of 3 mbar. The fast 2.45 MeV D-D neutrons are thermalized before irradiating the sample. The decay gammas from the radioisotopes Dy-165m (T-1/2 = 1.26 min.), Mn-56 (T-1/2 = 2.58 hrs.), and Au-198 (T-1/2 = 2.69 days) produced via reactions, Dy-164m (n, gamma)Dy-165m, Mn-55(n, gamma) Mn-56, and Au-197(n, gamma) Au-198 respectively are counted off-line in a lead shielded well type 76 x 76 mm(2) Nal(Tl) detector coupled to a calibrated 2048 channel analyzer. The values of half-lives evaluated from the measured decay gammas, 1.43 +/- 0.3 min., 2.56 +/- 0.5 hrs. and 2.84 +/- 0.6 days respectively for the radioisotopes of Dy, Mn and Au, are seen to be close to the values reported in literature. (C) 2018 Elsevier B.V. All rights reserved.