Application of medium energy plasma focus device in study of radioisotopes

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)×109 neutrons/pulse with a pulse width of 46±5ns 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 165mDy (T1/2=1.26min.), 56Mn (T1/2=2.58hrs.), and 198Au (T1/2=2.69days) produced via reactions, 164Dy(n,γ)165mDy, 55Mn(n,γ) 56Mn, and 197Au(n,γ) 198Au respectively are counted off-line in a lead shielded well type 76×76mm2 NaI(Tl) detector coupled to a calibrated 2048 channel analyzer. The values of half-lives evaluated from the measured decay gammas, 1.43±0.3min., 2.56±0.5hrs. and 2.84±0.6days respectively for the radioisotopes of Dy, Mn and Au, are seen to be close to the values reported in literature.