Nguyen Xuan Hai

Determination of selenium in geological sample by event–event coincidence technique

Selenium plays a role in thyroid function and your immune system which needs selenium to work properly. The quantifying Se in the biological and geological samples are very important to study transferring factor. The advantage of coincidence technique is abilities of background reduction. This technique has been applied for neutron activation analysis (NAA). In this paper, we would like to present the results of selenium determination in geology sample by NAA combined with the technique of event–event coincidence measurement. By application of this technique, the influence isotopes as 182Ta, 181Hf, 152Eu were eliminated.

Determining Experimental Transition Strengths of 52 V by Two-Step Gamma Cascades

In this paper, the results showed experimental transition strengths of 52 V by two-step gamma cascades, lifetime levels, width levels and branch ratio. 51 V nucleus was activated by thermal neutron at the 3 rd horizontal channel of Dalat nuclear reactor, and the 51 V(nth, 2 gamma) 52 V reaction was applied in this research. The two-step gamma cascades were collected by event-event gamma coincidence system. The Summation of Amplitude Coincidence Pulses method (SACP) was treated with the experimental data. The results were not affected by background based on SACP method. This method got intensities, energies of two-step cascades directly. The experimental gamma transition strengths were applied to the single particle model. In comparison with the electromagnetic transition probabilities, and rule of multi orders, the spin and parity of intermediate levels were calculated and refreshed.