"Experimental Studying of the Nuclear Reaction 10B(n,𝛼)7Li by Using Solid State Nuclear Detector CR-39 for Using in Neutron Activation Analysis "

Abstract

"Abstract To study the (n,𝛼) nuclear reaction, we chose the 10B(n,𝛼)7Li nuclear reaction according to the following: in an experiments performed during this work, discs or solutions of boron compounds (boric acid or sodium tetraborate) of different weights or concentrations were prepared and exposed to thermal neutron source (Am-Be). New trend in applying nuclear solid state track detector CR-39 for neutron activation analysis of boron compounds in environmental samples was studied. The effect of the naturally abundant elements, usually present in the environment, was examined. The study include the contribution of nine element viz Al, O, Na, Cl, P, Ca, Si, K, and Cu, concentration of boron compounds (50 µL + 50 ppm) with one of above elements (50 µL + 50 ppm) were prepared and irradiated for 72 hours. The results indicate that only a decrease of -0.187 % in the boric acid signal, while an increase of 0.539 % for sodium tetraborate signal. Both deviations are very small. The method can be applied to measure boron in simulated environmental and industrial soil samples with recovery within the range 96-100 %, good precision and accuracy ± 1.5 - 3.0 %. The method sensitivity can be enhanced by using longer irradiation time and few micrograms of boron can be analyzed, and hence it can be used in activation analysis. Also the dependence of track diameters as a function of etching time, the variation of the track etch rate and the etch rate ratio as a function time for different incident alpha particle energies are discussed. The etch processing was carried out in 6.25 N NaOH at 70±1°C temperature at 3 hr, resulting in a bulk etch rate of VB= 1.39 ±0.05μm/h. We observed that alpha tracks started to appear after 1st hour from the beginning of etching time. It can be seen that the track diameter increases, with increasing etching time for incident alpha particle energy from 0.8 to 1.47 MeV. The maximum value of VT max corresponding to the Bragg top of the energy loss that then gets the greatest loss of energy of the particle before stopping. The mathematical model of the cross section developed here gives the relationship between alpha-particles-emitting from the (n, α) reaction and the number of tracks created and distribution of tracks created on the surface of the track detector. From previous data the cross section was calculated and compared with theory researches of other researchers (3797 barn[present work], 3842 barn [Zang], 3840 barn [Barbara])."