Browsing by Author "Kaynak G."

Now showing 1 - 12 of 12

A study on atomic number and energy dependence of coherent scattering coefficients
(2013-01-01) Gurler O.; Oktar C.; Yalcin S.; Kaynak G.
This study presents an analytic formula for calculation of the coherent attenuation coefficients of gamma rays for 100 elements in the energy range from 0.01 to 3 MeV. The analytic formula is based on WinXCOM. Comparisons were made of the analytic coherent attenuation coefficients with the coherent attenuation coefficients calculated with the WinXCOM. The results obtained with the analytic approach agree well with those calculated with the WinXCOM. © 2012 Elsevier Ltd. All rights reserved.
Analytical formulas for calculating photoelectric attenuation coefficients
(2012-12-01) Gurler O.; Oktar C.; Yalcin S.; Kaynak G.
Photoelectric absorption is an interaction in which an incoming gamma ray virtually transfers all of its energy to an atomic electron, usually the most tightly bound K-shell electron of an atom. This paper uses the Win XCOM computer code as a reference base. We found analytical photoelectric attenuation coefficients for researchers using the Monte Carlo simulation program for Z [1; 100] and E[10keV; 3MeV]. We define a photoelectric effect operator and coefficient operators and a series for photoelectric absorption. We have calculated two polynomial coefficient operators for use with XCOM for photoelectric absorption. We determined 14 energies and atomic number limits for elements, and we find that they are accurate limits of photoelectric absorption for fitting with XCOM. © 2012 Copyright Taylor and Francis Group, LLC.
Calculation of angular distribution of 662 keV gamma rays by Monte Carlo method in copper medium
(2009-12-01) Kahraman A.; Ozmutlu E.; Gurler O.; Yalcin S.; Kaynak G.; Gundogdu O.
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 51×51 mm NaI(Tl) detector at 60° angle with incoming photons scattered from a 10 mm thick copper layer has been determined using Monte Carlo method. © 2009 Elsevier Ltd. All rights reserved.
Calculation of total counting efficiency of a NaI(Tl) detector by hybrid Monte-Carlo method for point and disk sources
(2007-10-01) Yalcin S.; Gurler O.; Kaynak G.; Gundogdu O.
This paper presents results on the total gamma counting efficiency of a NaI(Tl) detector from point and disk sources. The directions of photons emitted from the source were determined by Monte-Carlo techniques and the photon path lengths in the detector were determined by analytic equations depending on photon directions. This is called the hybrid Monte-Carlo method where analytical expressions are incorporated into the Monte-Carlo simulations. A major advantage of this technique is the short computation time compared to other techniques on similar computational platforms. Another advantage is the flexibility for inputting detector-related parameters (such as source-detector distance, detector radius, source radius, detector linear attenuation coefficient) into the algorithm developed, thus making it an easy and flexible method to apply to other detector systems and configurations. The results of the total counting efficiency model put forward for point and disc sources were compared with the previous work reported in the literature. © 2007 Elsevier Ltd. All rights reserved.
Evaluation of radon concentration in well and tap waters in Bursa, Turkey
(2012-06-01) Akar Tarim U.; Gurler O.; Akkaya G.; Kilic N.; Yalcin S.; Kaynak G.; Gundogdu O.
222Rn 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 222Rn intake through water consumption were 0.02 mSv a -1 and 1.11 mSv a -1, respectively. © The Author 2011. Published by Oxford University Press.
Investigation of environmental contamination in lichens of Gökçeada (Imbroz) Island in Turkey
(2009-02-01) Kahraman A.; Kaynak G.; Gurler O.; Yalcin S.; Ozturk S.; Gundogdu O.
The main objective of the present study is to determine the type of environmental contamination in lichens in Gökçeada Island in the Northern Aegean Sea in Turkey. We used two different lichen species Cladonia foliacea and Ramalina pollinaria. In the first part of the investigation, the beta activities of lichens have been measured by using a TENNELEC LB 1000-PW detector. The range of beta activity values was between 607 ± 30 and 308 ± 12 Bq/kg for C. foliacea lichens collected from around Tuz Lake and values for R. pollinaria lichens were found to be 740 ± 25 and 541 ± 17 Bq/kg. The second part of the study was concerned with the gamma spectra of the lichen samples measured by using HpGe detector. 137Cs, 134Cs, 40K, 232Th, 226Ra radionuclides were found in C. foliacea collected from around Tepeköy and in R. pollinaria from around Tuz Lake. When these two types of lichens were compared, it was found that R. pollinaria contain more radionuclides. In order to compare and determine which of these lichens act as a better bioaccumulator, K, Mn, Zn, Rb, Sr, Ba and Pb metal content were determined by using Energy Dispersive X-ray fluorescence spectrometry. It was found that C. foliacea collected more Mn and Sr when compared to R. pollinaria. © 2009 Elsevier Ltd. All rights reserved.
Measurements of radium levels in bottled natural spring water of marmara region (Turkey)
(2012-09-24) Akar U.; Gurler O.; Kahraman A.; Yalcin S.; Kaynak G.; Gundogdu O.
Drinking water may contain varying levels of radioactivity. It is therefore important to determine the radium levels in drinking waters for public health and radiation protection. This paper presents results of 226Ra concentrations in bottled spring waters. The concentration of radium has been assessed in the bottled natural spring water samples commercially available in Turkey. Measurements of 226Ra concentrations in bottled natural spring water samples were carried out by AlphaGUARD, measuring the radon in equilibrium with radium. The radium concentration in these samples is found to be between 0.03 and 0.43 Bq·L-1. These values were compared with the recommended safe limits for drinking water.
Measurements of radon concentration in drinking water samples from Kastamonu (Turkey)
(2011-12-01) Yalcin S.; Gurler O.; Tarim U.A.; Incirci F.; Kaynak G.; Gundogdu O.
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. © 2011 Copyright Taylor and Francis Group, LLC.
Measurements of radon levels in thermal waters of Bursa, Turkey
(2010-12-01) Gurler O.; Akar U.; Kahraman A.; Yalcin S.; Kaynak G.; Gundogdu O.
Radon (222Rn) is a tasteless, colourless and odourless radioactive noble gas, responsible for approximately 50% of radiation from natural sources. Being highly soluble in water, radon in water sources is also a major public health concern and is still an active research area. This paper presents the results of radon concentration measurements in thermal water samples from Çekirge region of the city of Bursa, rich in geothermal waters located in the northwest part of Turkey. The radon activity concentrations in 36 thermal water samples were determined by using AlphaGUARD PQ 2000PRO radon gas analyser. AlphaGUARD is an ionizing chamber which measures radon via alpha spectrometric techniques. It is found that the concentration ranged from 2.513 + 0.286 to 82.55311.919 Bq·L-1 for radon. The doses delivered to the users during treatment were also calculated and found to be in the range of 0.36 nSv to 11.89 nSv per treatment. © by PSP.
Monte Carlo simulation of gamma-ray total counting efficiency for a Phoswich detector
(2009-01-01) Yalcin S.; Gurler O.; Gundogdu O.; Kaynak G.
The LB 1000-PW detector is mainly used for determining total alpha, beta and gamma activity of low activity natural sources such as water, soil, air filters and any other environmental sources. Detector efficiency needs to be known in order to measure the absolute activity of such samples. This paper presents results on the total gamma counting efficiency of a Phoswich detector from point and disk sources. The directions of photons emitted from the source were determined by Monte Carlo techniques and the true path lengths in the detector were determined by analytical equations depending on photon directions. Results are tabulated for various gamma energies. © 2008 Elsevier Ltd. All rights reserved.
Mosses beta radioactivity in Katirh mountain-Bursa, TURKEY
(2007-08-03) Kahraman A.G.; Kaynak G.; Akkaya G.; Gultekin A.; Gurler O.; Yalcin S.
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 Katirh 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. © 2007 American Institute of Physics.
Radioactivity measurements in epiphytic lichens of Uludaǧ Mountain in Western Anatolia
(2013-01-01) Kahraman A.; Kaynak G.; Akkaya G.; Gürler O.; Yalçın S.
Activity concentrations of gross-β, naturally occurring 226 Ra, 232 Th, 210 Pb, 7 Be and anthropogenic 137 Cs in epiphytic lichens collected from Uludaǧ Mountain are presented and discussed with the aim of evaluating potential usability of lichens as a biomonitor. The activity concentrations of gross-β, 137 Cs, 40 K, 226 Ra, 232 Th, 210 Pb and 7 Be in the lichen samples were found to be in the range of 177-707, 4.05-94.26, 86-211, below detection limit (BDL) - 19.2, BDL - 14.0, 229-872, and 72.1-220.7 Bq kg -1 in dry weight, respectively. 137 Cs content in collected epiphytic lichens was in descending order: Parmelia sulcata > Lobaria pulmonaria > Pseudevernia furfuracea > Usnea filipendula. The best biomonitor for 137 Cs among the lichen species used in this study was determined as Parmelia sulcata. Pearson's correlation coefficient was calculated between 137 Cs and 40 K activity concentrations using a statistical package program (SPSS ver. 17.0) and a negative correlation value (R = -0,323, p = 0,222) was obtained. The highest 226 Ra and 232 Th activity concentrations were found in Boǧazova YaylasI which has a geological structure including granitic rocks. It was found that 137 Cs and 7 Be activity concentrations in species demonstrated an inverse behaviour. The effect of mean annual precipitation and temperature on 7 Be activity concentration was determined using multi regression analysis. Also, correlations between the 137 Cs and 7 Be, and 40 K and 7 Be were investigated. © 2012 Akadémiai Kiadó, Budapest, Hungary.