Vuong Huu Tan

Determination of \(\gamma\)-rays Relative Intensities from the \(^{35}\)Cl\((n, \gamma )^{36}\text{Cl}\) Reaction on Filtered Thermal Neutron Beam

The relative intensities of prompt g-rays from the 35 Cl(n, g) 36 Cl reation with thermal neutron have been used as secondary g-ray intensity standards for the prompt gamma neutron activation analysis (PGNAA) and for nuclear data measurements due to a high capture cross section. The filter neutron technique was applied for producing a thermal neutron beam at the neutron channel N o . 4 of the Dalat nuclear research reactor. The neutron flux and Cd-ratio are 8.72 ´ 10 6 n.cm -2 .s -1 and 134, respectively, determined by the gold foil activation method. A new PGNAA system with a HPGe detector of 58% relative efficiency and a digital spectrometer was used to detect prompt gamma rays from the 35 Cl(n, g) 36 Cl reaction. In this work, relative intensities of 23 prompt g-rays have been determined on the filtered thermal neutron beam. The present results within accuracy 3.0% or better are in good agreement with literature values and data from previous measurements.

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.