Browsing by Author "Akkaya, Gizem"

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Bursa ili toprak numunelerinde radyonüklid dağılımının incelenmesi
(Uludağ Üniversitesi, 2011-07-19) Akkaya, Gizem; Kaynak, Z. Gökay; Uludağ Üniversitesi/Fen Bilimleri Enstitüsü/Fizik Anabilim Dalı.
Bu çalışmada toprak örneklerindeki radyonüklid konsantrasyonları araştırılarak, Bursa' nın radyoaktivite seviyesi radyolojik açıdan değerlendirilmiştir. 26 adet yüzey toprağındaki 226Ra, 232Th, 40K ve 137Cs radyonüklidlerinin aktiviteleri bulunmuştur. Toprak örneklerindeki radyonüklid aktiviteleri HpGe detektörlü gamma spektrometresi kullanılarak ölçülmüştür. 226Ra, 232Th, 40K ve 137Cs aktiviteleri sırasıyla 10 - 120 Bq/kg (ortalama değer 24 Bq/kg), 12 - 235 Bq/kg (ortalama değer 30 Bq/kg), 257 ? 1 330 Bq/kg (ortalama değer 433 Bq/kg), 1,01 - 48,97 Bq/kg (ortalama değer 5,66 Bq/kg) aralıklarında bulunmuştur.Ayrıca ortalama havada soğrulan doz oranı (ADRA), yıllık efektif doz eşdeğeri (AEDE), radyum eşdeğer aktivite değeri (Raeq) ve dış kaynaklı tehlike göstergesi (Hex) sırasıyla 62 nGy/h, 76 Sv/y, 133 Bq/kg ve 0,36 olarak bulunmuştur. Elde edilen sonuçlar literatür değerleriyle karşılaştırılmıştır. 108 adet yüzey toprağı örneğinin toplam beta aktiviteleri Tennelec LB 1000-PW detektör kullanılarak belirlenmiştir. Ölçülen toplam beta aktiviteleri 46 - 2 780 Bq/kg aralığında (ortalama değer 556 Bq/kg) elde edilmiştir.Bu çalışma Bursa ilinin radyasyon haritasının çıkarılmasına katkı sağlayacaktır. Çalışma, Bursa ilindeki topraklarda bulunan doğal ve yapay radyonüklid aktivitelerinin belirlendiği ilk detaylı çalışmadır. Elde edilen sonuçlar, insan kaynaklı herhangi bir radyoaktivite seviyesindeki değişikliğin tespit edilebilmesi açısından önemlidir.
Correlation of radon and thoron concentrations with natural radioactivity of soil in Zonguldak, Turkey
(Amer Inst Physics, 2017) Koray, Abdullah; Akkuş, B.; Öktem, Y.; Doğan, G. S.; Güzelçimen, F.; Akkaya, Gizem; Kahraman, Ayşegül; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü.; 0000-0002-1836-7033; AAH-8784-2021; AAH-6441-2021; 18036694200; 47161190600
Radon and thoron gases are produced by the decay of the radioactive elements those are radium and thorium in the soil. In this study, the correlations between soil radon and thoron concentration with their parent nuclide (Ra-226 and Th-232) concentrations in collected soil samples from the same locations were evaluated. The result of the measurement shows that the distribution of radon and thoron in soil showed the same tendency as Ra-226 and Th-232 distribution. It was found a weak correlation between the radon and the Ra-226 concentration (R =0.57), and between the thoron and the Th-232 concentration (R=0.64). No strong correlation was observed between soil-gas radon and thoron concentration (R=0.29).
Determination of manganese content in some commercial manganese ores in Turkey k0-NAA standardization method using 241Am-Be isotopic neutron
(Amer, 2019-01-01) Akkaya, Gizem; Yücel, Haluk; Budak, Mustafa Güray; Mishonov, TM; Varonov, AM; AKKAYA, GİZEM; Bursa Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü; Mishonov, TM; Varonov, AM; AAH-8784-2021
In this study, the k(0)-NAA standardization method was applied to determine manganese concentrations in commercial manganese ores that collected different mining sites in Turkey. The samples were grinded, sieved and filled into Teflon tubes with a thickness of 1mm and then irradiated in one irradiation cell of the 37GBq M-241-Be isotopic neutron source. The activities of the irradiated manganese-ore samples were produced via Mn-55(n,gamma) Mn-56 reaction and were measured by using a n-type coaxial HPGe detector with 78.5% relative efficiency. The peak area analysis of the 846.8 keV (98.85%) and 1810.7 keV (26.9%) gamma-ray lines of 56 Mn product radionuclide were performed. Experimental data of the Au-197(n,gamma) Au-198 standard monitor reaction, the neutron flux parameters in the irradiation cell and related nuclear data were used together to determine manganese concentrations in the samples. The manganese contents in five different mining sites were found to be 2.63 +/- 0.23(%) for MH (Malatya Hekimhan), 13.78 +/- 0.98(%) for EA (Elazig-Akboga), 21.53 +/- 1.52(%) for AK (Ankara Kalecik), 34.09 +/- 2.38(%) for AB (Adiyaman Besni), 41.36 +/- 2.89(%) for AG (Adiyaman Golbasi). The results indicated that k(0)-NAA method with use of an isotopic neutron source can be successfully applied to the analysis of manganese ores.
Estimation of radiological exposure levels in a mining area based on ²³⁸U, ²²⁶Ra, ²³²Th and ⁴⁰K activity measurements: A case study for Beylikova-Sivrihisar complex ore site in Turkey (vol 190, pg 297, 2020)
(Oxford Univ Press, 2021-02-22) Yücel, Haluk; Ovuç, Süleyman; Akkaya, Gizem; Çakmak, Sadiye; AKKAYA, GİZEM; Bursa Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü.; AAH-8784-2021
Estimation of radiological exposure levels in a mining area based on U-238, Ra-226, Th-232 and K-40 activity measurements: A case study for Beylikova-Sivrihisar complex ore site in Turkey
(Oxford University Press, 2020-08-11) Yücel, Haluk; Övüç, Süleyman; Akkaya, Gizem; Çakmak, Şadiye; Bursa Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü.; 0000-0002-6573-2101; AAY-9963-2021; AAB-1751-2021; AAH-8784-2021; 18036694200; 56182632200
The study estimated the radiological exposure levels in a mining area for miners in the Beylikova-Sivrihisar (Turkey) complex ore site containing U-238, Ra-226 and Th-232. Sixty samples were collected from the study area based on a geologic map. The radionuclide activities were measured using a 78.5% efficient n-type HPGe detector. The measured mean activities were 1871 +/- 38 Bq kg(-1) for U-238, 1749 +/- 5 Bq kg(-1) for Ra-226, 3467 +/- 9 Bq kg(-1) for Th-232 and 309 +/- 2 Bq kg(-1) for K-40. From the measured results, the external effective dose was calculated to be max. 3.80 +/- 0.03 mSv y(-1) (mean: 2.04 +/- 0.03 mSv y(-1)) for inside gallery and max. 7.59 +/- 0.05 mSv y(-1) (mean: 4.08 +/- 0.05 mSv y(-1)) for outdoor. Additionally, the external exposure index was calculated to be H-ex = 33.5 +/- 0.2(mean: 18.2 +/- 0.3) and internal exposure index to be H-in = 45.9 +/- 0.3 (mean: 22.9 +/- 0.4). The results indicate that additional radiation protection measures should be taken during the mining process if an opencast mining is implemented in Beylikova complex ore deposit.
Evaluation of radon concentration in well and tap waters in Bursa, Turkey
(Oxford Univ, 2012-06) Yalçın, Sezai; Gündoğdu, Özcan; Tarım, Ürkiye Akar; Gürler, Orhan; Akkaya, Gizem; Kılıç, Nizamettin; Kaynak, Gökay; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü.; AAH-4270-2021; AAI-3656-2021; AAH-1837-2021; AAH-8784-2021; 55062460600; 14019444500; 18036694200; 7005266570; 12042075600
Rn-222 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 Rn-222 intake through water consumption were 0.02 Sv a(1) and 1.11 Sv a(1), respectively.
The investigation of radionuclide concentrations in soil and lifetime cancer risk due to gamma radioactivity in Zonguldak, Turkey
(Polish Acad Sciences Inst Physics, 2017-09) Koray, Abdullah; Baldık, Rıdvan; Akkaya, Gizem; Kahraman, Ayşegül; Kaynak, Gökay; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü.; 0000-0002-1836-7033; AAH-8784-2021; AAH-6441-2021; 18036694200; 47161190600; 12042075600
The distributions of Ra-226, Th-232, K-40 and Cs-137 activity concentrations were determined using a high-purity germanium detector in uncultivated surface soil samples collected from Zonguldak. The range of Ra-226, Th-232, K-40 and 137Cs activity concentrations varied from 10.5 +/- 2.0 to 98.0 +/- 4.3 Bq kg(-1) (mean value 28.8 +/- 4 Bq kg(-1)), from 12.9 +/- 3.4 to 53.2 +/- 5.1 Bq kg(-1) (mean value 29.6 +/- 3 Bq kg(-1)), from 190 +/- 22 to 808 +/- 43 Bq kg(-1) (mean value 395 +/- 31 Bq kg(-1)) and from < 0.5 to 47.1 +/- kg(-1) (mean value 12.5 +/- 2 Bq kg(-1)), respectively. In addition, the mean outdoor absorbed dose rates in air (terrestrial, terrestrial+cosmic), annual effective dose equivalent, radium equivalent activity and external hazard index were found to be 48 nGy h(-1) (terrestrial), 56 nGy h(-1) (terrestrial+cosmic), 58 mu Sv y(-1), 101 Bq kg(-1) and 0.27, respectively. The evaluated excess lifetime cancer risks (ELCRs) varied from 0.13 x 10(-3) to 0.36 x 10(-3) with a mean value of 0.20 x 10(-3).
The investigation of radionuclide distributions in soil samples collected from Bursa, Turkey
(Oxford University, 2012-12) Akkaya, Gizem; Kaynak, Gökay; Kahraman, Ayşegül G.; Gürler, Orhan; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü.; 0000-0002-1836-7033; AAH-1837-2021; AAH-6441-2021; AAH-8784-2021; 18036694200; 12042075600; 47161190600; 14019444500
The distributions of Ra-226, Th-232, K-40 and Cs-137 activity concentrations were determined using a high-purity germanium detector in uncultivated surface soil samples collected from Bursa. The range of Ra-226, Th-232, K-40 and Cs-137 activity concentrations varied from 101 to 613 Bq kg(1) (mean value 253 Bq kg(1)), from 121 to 502 Bq kg(1) (mean value 263 Bq kg(1)), from 2575 to 101011 Bq kg(1) (mean value 43544 Bq kg(1)) and from 1.010.07 to 48.970.54 Bq kg(1) (mean value 8.522.59 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 Sv 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 469 to 1199113 Bq kg(1) with a mean value of 54119 Bq kg(1).
Measurements of radon concentrations in waters and soil gas of Zonguldak, Turkey
(Oxford University Press, 2014-12) Koray, Abdullah; Akkaya, Gizem; Kahraman, Ayşegül G.; Kaynak, Gökay; Uludağ Üniversitesi/Fen Edebiyat Fakültesi/Fizik Bölümü.; 0000-0002-1836-7033; AAH-6441-2021; AAH-8784-2021; CYZ-0032-2022; 18036694200; 47161190600; 12042075600
The radon concentrations in soil-gas and water samples (in the form of springs, catchment, tap, thermal) used as drinking water or thermal were measured using a professional radon monitor AlphaGUARD PQ 2000PRO. The measured radon concentrations in water samples ranged from 0.32 to 88.22 Bq l-1. Most of radon levels in potable water samples are below the maximum contaminant level of 11 Bq l-1 recommended by the US Environmental Protection Agency. The calculated annual effective doses due to radon intake through water consumption varied from 0.07 to 18.53 μSv y-1. The radon concentrations in soil gas varied from 295.67 to 70 852.92 Bq m-3. The radon level in soil gas was found to be higher in the area close to the formation boundary thrust and faults. No correlation was observed between radon concentrations in groundwater and soil gas. Also, no significant correlation was observed between soil-gas radon and temperature, pressure and humidity. The emanation of radon from groundwater and soil gas is controlled by the geological formation and by the tectonic structure of the area. © The Author 2013. Published by Oxford University Press. All rights reserved.
Neutron self-shielding correction in application of k(0)-NAA standardization method to determine Mn content in manganese ores
(Elsevier, 2020-04-15) Yücel, Haluk; Budak, Mustafa Güray; Akkaya, Gizem; Bursa Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü.; 0000-0002-6573-2101; AAH-8784-2021; 18036694200
In this study, it is aimed to investigate neutron self-shielding effect in application of k(0)-NAA standardization method to determine Mn contents in manganese ores. Because the neutron self-shielding correction factors are significant factors in application of k(0)-NAA method for large samples. To estimate these, several Mn-ore samples and Au monitor were irradiated separately in a 37 GBq Am-241-Be neutron source irradiation unit and then they were measured by using a 78.5% relative efficient HPGe detector. In this study, the sigmoid function approaches for calculation of G(th) and G(e) factors were applied for the right cylinder sample geometry at known elemental compositions in samples, determined by EDXRF technique with a 25 mm(2) Silicon Drift Detector (SDD). The present results indicate that k(0)-NAA method is applicable successfully to determine Mn contents in Mn-ore samples providing that G(th) and G(e) factors are estimated accurately even if a low-flux isotopic neutron source is used.
Radioactivity measurements in epiphytic lichens of Uludag Mountain in Western Anatolia
(Springer, 2013-02) Yalçın, Sezai; Kahraman, Ayşegül G.; Kaynak, Gökay; Akkaya, Gizem; Gürler, Orhan; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fİzik Bölümü.; 0000-0002-1836-7033; AAH-1837-2021; AAH-6441-2021; AAH-8784-2021; 47161190600; 12042075600; 18036694200; 14019444500
Activity concentrations of gross-beta, naturally occurring Ra-226, Th-232, Pb-210, Be-7 and anthropogenic Cs-137 in epiphytic lichens collected from Uludag Mountain are presented and discussed with the aim of evaluating potential usability of lichens as a biomonitor. The activity concentrations of gross-beta, Cs-137, K-40, Ra-226, Th-232, Pb-210 and Be-7 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. Cs-137 content in collected epiphytic lichens was in descending order: Parmelia sulcata > Lobaria pulmonaria > Pseudevernia furfuracea > Usnea filipendula. The best biomonitor for Cs-137 among the lichen species used in this study was determined as Parmelia sulcata. Pearson's correlation coefficient was calculated between Cs-137 and K-40 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 Ra-226 and Th-232 activity concentrations were found in Bogazova YaylasA +/- which has a geological structure including granitic rocks. It was found that Cs-137 and Be-7 activity concentrations in species demonstrated an inverse behaviour. The effect of mean annual precipitation and temperature on Be-7 activity concentration was determined using multi regression analysis. Also, correlations between the Cs-137 and Be-7, and K-40 and Be-7 were investigated.
The calculation of self-shielding correction factors for large samples in ²⁴¹Am-Be isotopic neutron source
(Pergamon-Elsevier, 2021-10-19) Akkaya, Gizem; AKKAYA, GİZEM; Bursa Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü.; AAH-8784-2021
In the present study, it is aimed to calculate neutron self-shielding correction factors for cylinder sample geometry using different methods in the literature in the application of k(0)-NAA standardization method with Am-241-Be isotopic neutron source. These correction factors are important in calculating the accurate concentration values for large samples with a high neutron absorption cross-section in the application of the k(0)-NAA method. In order to see the validity of the applied theoretical and experimental methods, the obtained concentration values are given comparatively with respect to the known Mn concentrations. The mean concentration difference ranges from-3.4% to-9.7%. The thermal neutron self-shielding correction depends on all elements in the sample that absorb thermal neutrons. In k(0)-NAA applications with large samples, although timeconsuming, it is recommended to use the experimental methods after calculating the necessary parameters with the help of samples with known composition.
Variation in the radon concentrations and outdoor gamma radiation levels in relation to different geological formations in the thermal regions of Bursa, Turkey
(IOP Publishing, 2016-05-13) Koray, Abdullah; Akkaya, Gizem; Kahraman, Ayşegül; Kaynak, Gökay; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü.; 0000-0002-1836-7033; AAH-6441-2021; AAH-8784-2021; 18036694200; 47161190600; 12042075600
Spring waters used as spas and their region may contain significant amounts of natural radionuclides. The main sources of exposure are the inhalation of radon and its decay products released from the water and soil and terrestrial gamma-radiation. In order to evaluate the potential risk of thermal regions in Bursa, located in the impact area of the NAF (North Anatolian Fault), radon and thoron concentrations in soil gas, radon concentrations in thermal waters and outdoor gamma radiation levels were measured in thermal regions that have different geological formations. The radon and thoron concentrations in soil-gas were found to vary from 2272 +/- 121 to 245196 +/- 3455 Bq m(-3) and from 999 +/- 218 to 178 848 +/- 17 742 Bq m(-3), respectively. The radon concentrations in thermal waters ranged from 0.99 +/- 0.21 to 226.74 +/- 2.51 Bq l(-1) in the rainy season and from 0.26 +/- 0.10 to 178.03 +/- 12.86 Bq l(-1) in the dry season. The measured outdoor gamma radiation levels varied from 38 to 180 nGy h(-1). The gamma dose rates were found to be strong positively correlating with the radon and thoron concentrations in soil-gas. The radon and outdoor gamma radiation levels were observed to be a function of the geological formations of the area.