Pravina P. Pawar

Effects of gamma irradiation on some chemicals using an NaI (Tl) detector

ABSTRACT The present work was carried out to find out the gamma ray shielding properties and to study the effects using an NaI (Tl) detector using radioactive sources 57Co, 133Ba, 137Cs, 54Mn, 60Co and 22Na at energies 122, 356, 511, 662, 840, 1170, 1275 and 1330 keV, for some chemicals, namely, sodium thiosulfate (Na2S2O3), benzoic acid (C7H6O2), sodium hydroxide (NaOH), poly vinyl alcohol (PVA) (C2H4O), potassium nitrate (KNO3), naphthalene (C10H8). Mass attenuation coefficient (µm) values obtained from the experiment were used to determine the effective atomic numbers (Zeff) and effective electron densities (Neff), atomic cross-sections (σt) and electronic cross-sections (σe); it will be observed from the present work that the variation in the obtained values is only due to the increase or decrease in the gamma ray energy and the chemical composition of the sample. It was seen that the calculated and obtained values showed good agreement. The investigated data are useful in the electronic industry, plastic industry, building materials and agriculture fields. From the present work it was found that the PVA could be used as a better gamma shielding material.

Detection of new polymer materials as gamma-ray-shielding materials

ABSTRACT Mass attenuation coefficients (µm), total atomic cross-sections (σt), molar extinction coefficients (), electronic cross-sections (σe), effective atomic numbers (Zeff) and electron densities (Neff) have been computed for few nylons that are polymers, namely, nylon 6 (C6H11ON), nylon 1,1 (C11H21ON), nylon 6,6 (C12H22O2N2), nylon 6,9 (C15H28O2N2), nylon 6,10 (C16H30O2N2) and nylon 6,12 (C18H34O2N2) using narrow beam good geometry set-up. In the present investigation, radio-nuclides 57CO, 133Ba, 137Cs, Co57, Ba133, Cs137, Na22, Mn54 and Co60 emitting energies 122, 356, 511, 662, 840, 1170, 1275 and 1330 keV have been counted by a NaI (Tl) detector coupled with the 8 K multichannel analyzer. Values of µm, σt and σe decrease with increasing energy of gamma photons due to the dominance of Compton scattering in the selected energy range. Effective atomic numbers of chosen samples tend to be almost constant as a function of energy. It is clearly observed from the computed results that the among the chosen samples nylon 1,1 has good absorption capability of gamma photons in the low energy region. An attempt has been made to investigate the new gamma-ray-shielding materials that can be used at a large scale and that will be available at low cost.

Photon attenuation coefficients of different rock samples using MCNPX, Geant4 simulation codes and experimental results: a comparison study

ABSTRACT The photon attenuation coefficients for the rocks (Feldspathic basalt, Compact basalt, Volcanic rock, Pink granite, Sandstone and Dolerite) have been investigated using MCNPX and Geant4 codes for photon energies 122, 356, 511, 662, 1170, 1275 and 1330 keV. Comparison of the simulation and experimental results of mass attenuation coefficients is presented. The exposure buildup factors also have been calculated with the help of the G-P fitting method. The comparison showed reasonable agreement between the simulated and experimental data for all rocks. The results show that sandstone has the highest mean free path as well as exposure buildup factor which signifies that sandstone requires a larger thickness for protection from photons.

Study of gamma ray energy absorption and exposure buildup factors for ferrites by geometric progression fitting method

ABSTRACT The gamma ray energy absorption and exposure buildup factors (EABF and EBF) were calculated for ferrites such as cobalt ferrite (CoFe2O4), zinc ferrite (ZnFe2O4), nickel ferrite (NiFe2O4) and magnesium ferrite (MgFe2O4) using five parametric geometric progression (G-P fitting) formula in the energy range 0.015–15.00 MeV up to the penetration depth 40 mean free path (mfp). The obtained data of absorption and exposure buildup factors have been studied as a function of incident photon energy and penetration depth. The obtained EABF and EBF data are useful for radiation dosimetry and radiation therapy.

Measurements of radiological data of some amino acids in the energy range 0.122-1.330MeV

Radiological parameters such as μm, σt, σe, Zeff and Neff of amino acids, namely Lysine (C6H15N2O2), Histidine (C6H9N3O2) and Arginine (C6H15N4O2), were measured using NaI (Tl)-based gamma spectrometry. Radioactive sources used in the study are 57Co, 133Ba, 137Cs, 54Mn, 60Co and 22Na. Gamma ray transmission method in a narrow beam good geometry set up was used in the study. The measured data were compared against XCOM-based data. The agreement is within 2%.

Mass energy-absorption coefficients and average atomic energy-absorption cross-sections for amino acids in the energy range 0.122-1.330 MeV

Mass attenuation coefficients of amino acids such as n-acetyl-l-tryptophan, n-acetyl-l-tyrosine and d-tryptophan were measured in the energy range 0.122-1.330 MeV. NaI (Tl) scintillation detection system was used to detect gamma rays with a resolution of 8.2% at 0.662 MeV. The measured attenuation coefficient values were then used to determine the mass energy-absorption coefficients (σa,en) and average atomic energy-absorption cross sections (μen/ρ) of the amino acids. Theoretical values were calculated based on XCOM data. Theoretical and experimental values are found to be in good agreement.