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Bu çalışma,03-08 Haziran 2016 tarihleri arasında Guildford[İngiltere]’da düzenlenen 2. International Conference on Dosimetry and its Applications (ICDA)’da bildiri olarak sunulmuştur. A Monte Carlo method was developed to investigate radiation shielding properties of bismuth borate glass. The mass attenuation coefficients and half-value layer parameters were determined for different fractional amounts of Bi2O3 in the glass samples for the 356, 662, 1173 and 1332 keV photon energies. A comparison of the theoretical and experimental attenuation coefficients is presented. UK Natl Phys Lab Int Radiat Phys Soc

We developed a simple Monte Carlo code to determine the mass attenuation coefficients of some soil samples at nine different gamma-ray energies (59.5, 80.9, 122.1, 159.0, 356.5, 511.0, 661.6, 1173.2 and 1332.5 keV). Results of the Monte Carlo calculations have been compared with tabulations based upon the results of photon cross section database (XCOM) and with experimental results by other researchers for the same samples. The calculated mass attenuation coefficients were found to be very close to the theoretical values and the experimental results.

A Monte Carlo simulation study has been conducted of 60Co photons Compton scattered in concrete, illustrating the degraded energy spectra of gamma-ray radiation. Results are produced representing a NaI(Tl) detector model. We were able to analyse energy distributions of photons that reach the detector system after suffering several successive Compton scatterings in the target. The predicted decrease in intensity of single- and multiple-scattering peaks with increase in thickness of the target medium are in good agreement with experimental observations and findings reported by others.

We have written a Monte Carlo code to simulate the experimental results of a previously reported study. We were able to analyse the energy distributions of photons that reached the detector system after suffering several successive Compton scatterings in the target. We have also investigated how the number of multiply backscattered events depends on the target thickness and the energy of the primary photons.

Investigation is made on the energy spectrum of photons originating from interactions of 662 key primary gamma-ray photons emitted by a point source positioned at the centre of a water equivalent solid phantom of dimensions 19 cm x 19 cm x 24 cm. Peaks resulting from total energy loss (photo-peak) and multiple and back scattering have been observed using a 51 mm x 51 mm Nal(TI) detector; good agreement being found between the measured and simulated response functions. The energy spectrum of the gamma photons obtained through the Monte Carlo simulation reveals local maxima at about 100 key and 210 keV, being also observed in the experimental response function. Such spectra can be used as a method of testing the water equivalence of solid phantom media before their use for dosimetry measurements.

In this study, a Monte Carlo program has been developed to simulate the response function of the NaI(Tl) detector with all features for Co-60 and Cs-137 and to investigate the effects of detector housing material on response function. The pulse height spectra in a 2aEuro(3) x 2aEuro(3) NaI(Tl) detector due to these gamma ray sources have been measured. Comparison of the experimentally obtained and simulated spectra shows that there is good agreement between both spectra. Energy distributions of gamma photons that generate the backscattering peak in the response function were obtained and the contribution of single, double and multiple Compton scattering events to these distributions was investigated.

Bu çalışma, 25-27 Şubat 2009 tarihleri arasında Vienna[Avusturya]’da düzenlenen 22. Seminar on Activation Analysis and Gamma Spectroscopy’da bildiri olarak sunulmuştur. This paper presents results on the angular distribution of Compton scattering of 662 keV gamma photons in both forward and backward hemispheres in copper medium. The number of scattered events graph has been determined for scattered gamma photons in both the forward and backward hemispheres and theoretical saturation thicknesses have been obtained using these results. Furthermore, response function of a 51 x 51 mm Nal(Tl) detector at 60 degrees angle with incoming photons scattered from a 10mm thick copper layer has been determined using Monte Carlo method.

Bu çalışma, 12-15 Ekim 2010 tarihleri arasında Florence[İtalya]’da düzenlenen International Conference on Radiation Effects on Semiconductor Materials, Detectors and Devices (RESMDD)’da bildiri olarak sunulmuştur. The silicon avalanche photo-diodes (APDs) in the CMS barrel electromagnetic calorimeter will be exposed to an integrated neutron fluence of about 2 x 10(13) n/cm(2) over 10 years of operation. High neutron fluences change the electrical properties of silicon detectors. The changes are proportional to the non-ionising energy loss in the APDs. Using the Geant4 toolkit, we have calculated the non-ionising energy loss as well as the rate of generation of primary defects in the APDs, for the expected neutron fluence.

An analogue Monte-Carlo code has been used to simulate the transport of positrons in copper with an incoming energy range of 60 eV-30 keV. The simulation technique is based mainly on the screened Rutherford differential cross section with a spin relativistic correction factor for elastic scattering including some extra total cross section information for low energies, Gryzinski's semi-empirical expression was used to simulate energy loss due to inelastic scattering and the Liljequist and Gryzinski models to calculate the total inelastic scattering cross section. The calculated results are compared with experimental data and those from other calculations. Good agreement is observed except in cases of backscattering.

Aydın, Asuman (Balikesir Author), An analogue Monte-Carlo code has been used to simulate the transport of positrons in copper with an incoming energy range of 60 eV-30 keV. The simulation technique is based mainly on the screened Rutherford differential cross section with a spin relativistic correction factor for elastic scattering including some extra total cross section information for low energies, Gryzinski's semi-empirical expression was used to simulate energy loss due to inelastic scattering and the Liljequist and Gryzinski models to calculate the total inelastic scattering cross section. The calculated results are compared with experimental data and those from other calculations. Good agreement is observed except in cases of backscattering.

Aydın, Asuman (Balikesir Author), The Monte Carlo code, which has been used previously to simulate the transport of positrons in aluminium and copper, was modified for simulating the positron transport in silver, tin, gold and lead with incident positron energies in the range of 159-960 keV. The calculated results have been compared with available experimental data and predictions from other calculations. Usually good agreement is observed except in cases of backscattering. (C) 1997 Elsevier Science Ltd.

We develop an algorithm, based on the acceptance-rejection method, with a simple envelope rejection function for sampling the angular distribution in Compton scattering from Klein-Nishina differential scattering cross section. The algorithm enhances the sampling efficiency for high-energy photons increasingly with increasing photon energies, The sampling efficiency is 79.6, 89.5, 92.3, 95.9, 96.6% for photon energies 1, 5, 10, 50, 100 MeV respectively. We compare the speed of our algorithm with some methods currently used and find that our method is faster than the others in most cases.