O. Gurler

Evaluation of radon concentration in well and tap waters in Bursa, Turkey

(222)Rn measurements in water samples collected from 27 wells and 19 taps that were supplied from the investigated wells were conducted using the AlphaGUARD PQ 2000PRO radon gas analyser at sites across several geologic formations within the city of Bursa, Turkey. The measured radon concentrations ranged from 1.46 to 53.64 Bq l(-1) for well water and from 0.91 to 12.58 Bq l(-1) for tap water. Of the 27 sites sampled, only 7 had radon levels above the safe limit of 11.1 Bq l(-1) recommended by the USEPA. In general, all determined concentrations were well below the 100 Bq l(-1) revised reference level proposed by the European Union. These values of radon concentrations in water samples are compared with those reported from other countries. Doses resulting from the consumption of these waters were calculated. The minimum and the maximum annual mean effective doses due to (222)Rn intake through water consumption were 0.02 µSv a(-1) and 1.11 µSv a(-1), respectively.

Measurements of radon concentration in drinking water samples from Kastamonu (Turkey)

Concentration of 222Rn was determined in selected natural spring and tap water samples collected during spring and summer seasons from Kastamonu, Turkey. The aim of this work was to produce a map of the radon concentrations in water sources of the province and to determine any potential radiological risk for the local population. Radon measurements were performed by an AlphaGUARD radon gas analyser. The average radon concentrations were found to vary from 0.39±0.02 to 12.73±0.39 Bq l−1 for natural springs and from 0.36±0.04 to 9.29±0.45 Bq l−1 for tap water in spring, from 0.50±0.09 to 19.21±1.00 Bq l−1 for natural springs and from 0.31±0.03 to 13.14±0.38 Bq l−1 for tap water in summer. Furthermore, the results are compared with international recommendations and concentrations reported for other countries. Doses resulting from the consumption of these waters were calculated. The effective dose equivalents due to the intake of the 222Rn present in these waters are expected to range from 0.93 to 32.54 μSv y−1 in summer and from 0.80 to 49.09 μSv y−1 in spring.

Monte Carlo analyses of multiple backscattering of gamma rays

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.

Calculation of gamma-ray mass attenuation coefficients of some Egyptian soil samples using Monte Carlo methods

Monte Carlo simulations, FLUKA and Geant4, were performed to study mass attenuation for various types of soil at 59.5, 356.5, 661.6, 1173.2 and 1332.5 keV photon energies. Appreciable variations are noted for all parameters by changing the photon energy and the chemical composition of the sample. The simulations parameters were compared with experimental data and the XCOM program. The simulations show that the calculated mass attenuation coefficient values were closer to experimental values better than those obtained theoretically using the XCOM database for the same soil samples. The results indicate that Geant4 and FLUKA can be applied to estimate mass attenuation for various biological materials at different energies. The Monte Carlo method may be employed to make additional calculations on the photon attenuation characteristics of different soil samples collected from other places.

Monte Carlo calculations of the energy deposited in biological samples and shielding materials

The energy deposited by gamma radiation from the Cs-137 isotope into body tissues (bone and muscle), tissue-like medium (water), and radiation shielding materials (concrete, lead, and water), which is of interest for radiation dosimetry, was obtained using a simple Monte Carlo algorithm. The algorithm also provides a realistic picture of the distribution of backscattered photons from the target and the distribution of photons scattered forward after several scatterings in the scatterer, which is useful in studying radiation shielding. The presented method in this work constitutes an attempt to evaluate the amount of energy absorbed by body tissues and shielding materials.

Mass absorption and mass energy transfer coefficients for 0.4-10 MeV gamma rays in elemental solids and gases.

The mass energy absorption, the mass energy transfer and mass absorption coefficients have been widely used for problems and applications involving dose calculations. Direct measurements of the coefficients are difficult, and theoretical computations are usually employed. In this paper, analytical equations are presented for determining the mass energy transfer and mass absorption coefficients for gamma rays with an incident energy range between 0.4 and 10 MeV in nitrogen, silicon, carbon, copper and sodium iodide. The mass absorption and mass energy transfer coefficients for gamma rays were calculated, and the results obtained were compared with the values reported in the literature.

The investigation of radionuclide distributions in soil samples collected from Bursa, Turkey.

The distributions of (226)Ra, (232)Th, (40)K and (137)Cs activity concentrations were determined using a high-purity germanium detector in uncultivated surface soil samples collected from Bursa. The range of (226)Ra, (232)Th, (40)K and (137)Cs activity concentrations varied from 10±1 to 61±3 Bq kg(-1) (mean value 25±3 Bq kg(-1)), from 12±1 to 50±2 Bq kg(-1) (mean value 26±3 Bq kg(-1)), from 257±5 to 1010±11 Bq kg(-1) (mean value 435±44 Bq kg(-1)) and from 1.01±0.07 to 48.97±0.54 Bq kg(-1) (mean value 8.52±2.59 Bq kg(-1)), respectively. In addition, the mean outdoor absorbed dose rates in air, annual effective dose equivalent, radium equivalent activity and external hazard index were found to be 45 nGy h(-1), 56 μSv y(-1), 96 Bq kg(-1) and 0.26, respectively. The gross beta activity concentrations were determined using a Tennelec LB 1000-PW detector. The range of gross beta activity concentrations varied from 46±9 to 1199±113 Bq kg(-1) with a mean value of 541±19 Bq kg(-1).

Calculation of angular distribution of 662 keV gamma rays by Monte Carlo method in copper medium.

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 NaI(Tl) detector at 60 degrees angle with incoming photons scattered from a 10mm thick copper layer has been determined using Monte Carlo method.

Mosses beta radioactivity in Katirli mountain‐Bursa, TURKEY

Mosses are one of the most widely used procedures to determine via plant of radioactive contamination. The high concentrating capacity of mosses may be used as bioindicator of environmental radioactive contamination. In this study, the mosses were collected in region of Katirli Mountain in northwestern Turkey, activities were determined using TENNELEC LB 1000‐PW detector. Samples of mosses growing on soil, rock, and tree bark were collected.

Determination of Radiation Shielding Properties of Some Polymer and Plastic Materials against Gamma-Rays

A Monte Carlo code is proposed for determination of mass attenuation coefficients of gamma rays for some polymer and plastic materials. It is based on simulation of interaction processes of gamma rays with the energy of 59.5, 80.9, 140.5, 279, 356.5, 511, 661.6, 1173.2, 1332.5 keV with matter. The method was tested by comparison of the simulation results with the literature values (ANSI/ANS-6.4.3 and GRIC toolkit). The compatible behaviour of mass attenuation coefficients versus incident photon energy for the investigated energy range approves the use of this code for the extended energy range and several materials. Also, the values of half-value layer were calculated for assessment of shielding effectiveness of these materials.