[en] The investigation of β^- particle interaction with matter has many applications in nuclear industrial and medical science. In this work, we have impose different loads on Al-Mg-Zn alloy and Al metal sheets with different thickness to investigate the effect of elastic stress on the absorption coefficient of β^- particles of 9^OSr. Also, we have modulated and analyzed the loads on specimens, using ANSYS9 program to determine the distribution of stress within the specimens. The results show a valuable increase of μ -value due to loading the specimens by certain amounts of stress, where the μ- value decreases as the stress on the samples increases

[en] In this experimental work the pressure induced phase transformation of silicon and Germanium has been studied. It was shown that at a particular value of applied pressure, (P_t), depending on the sample temperature, the electrical resistance of the specimen falls off to a metallic state. The main goal of this study was to find out how the phase transformation pressure, P_t, for a p-type silicon varies with the sample temperature. The results show that, the value of P_t, decreases linearly as the temperature of the sample increases. Meanwhile, other related results including the rate of resistance change in accordance with applied pressure on the sample at different temperatures (∼270-350 K), both for the semiconductor and the metallic state of the specimen were determined. In another effort, the amount of P_t, for an n-type germanium, but only at room temperature, was also determined

[en] Polymer-graphite powder composite behaves as a low-conductive material which can be used as an automatic fuse for adhesive connector in electrical circuits. The conductivity of this composite, below its transition temperature, T_t, depends on concentration of carbon powder, slowly decreases as the temperature increases. Meanwhile, the electrical resistivity of this material in transition temperature region severely increases. The amount of T_t, was found to be approximately 148 degrees for polyethylene-carbon independent of its concentration. In this work, the rate of change in electrical resistance of this composite in terms of temperature, carbon concentration and γ ray irradiation dose has been investigated. Also, the values of T_t, and the peak resistance temperature, T_p of samples in each case were determined. The results show that both values of T_t, and T_p decrease with increasing of irradiation dose. It has been found that the concentration of carbon powder has no significant effect on the transition temperatures of samples

[en] The aim of the present work is to investigate the feasibility of using weak sources in Compton scattering tomography to minimize radiological hazards. We designed a portable scanning system using a 5 mCi¹³⁷Cs source and a scintillation NaI detector. To compensate the source weakness a rectangular shaped collimator was placed in front of the detector which increased the solid angle subtended by the detector. Due to the lightweight and small size, the system can be easily used for in situ tomography

[en] Many results have been obtained in our previous studies on the effects of structural defects on the physical properties of crystalline materials. In this work, we are presenting our experimental results for the influence of the structural defects on the absorption coefficient and the penertration depth of β particles in aluminium metal. For this investigation, 3 pieces of Al foils, with different thicknesses were prepared. Then, one group of samples were annealed to show less defects. Other A1 samples were exposed to heavily defect creating work, such as: hammering, rolling, and thermal quenching treatments. Then, by the use of the conventional method, the penetration depth of P-particles of different energies from ⁹⁰Sr, ³⁶CI, and ¹³Cs sources were determined. Our results show that the measured R-values for the defected samples are higher than those of the annealed ones. Also, it was found that the penertration depth for the defected samples increases as the P-particle's energy increases