Browsing by Author "Akdemir, Fatma"

Now showing 1 - 2 of 2

Evaluation of Gamma-Ray Attenuation Properties of Lithium Borate Glasses Doped With Barite, Limonite and Serpentine
(Walter de Gruyter Gmbh, 2018) Yorgun, Nergiz Yildiz; Kavaz, Esra; Oto, Berna; Akdemir, Fatma
The values of mass attenuation coefficient, the effective atomic number and the electron density of barite-doped, limonite-doped, serpentine-doped and undoped lithium borate glasses were obtained not only from experimental study using the narrow beam transmission method for 81, 121, 244, 276, 344, 383, 444 and 778 keV gamma energies with Hp-Ge detector, but also therotical work by WinXCom software (1 keV-10(5) MeV). From the obtained results, all glasses type mass attenuation coefficient values tend to decrease under the condition of increasing energy by means of varied interaction mechanism in different energy regions. In addition, the effect of chemical composition on shielding properties was also investigated. It is inferred that doping element with high atomic number improves the gamma rays shielding properties of system. Among the investigated samples, barite-doped lithium borate glasses have highest value of mass attenuation, which makes barite-doped samples good candidates for artificial radiation application where visual detection is especially required.
Investigation of Gamma Radiation Shielding Properties of Various Ores
(Pergamon-elsevier Science Ltd, 2015) Oto, Berna; Yildiz, Nergiz; Akdemir, Fatma; Kavaz, Esra
Mass attenuation coefficients (mu/p, cm(2)/g) for some pellet samples produced using barite, magnetite, limonite, hematite and serpentine ores at 81, 276, 302, 356, 383 key photons emitted from Ba-133 and 121, 244, 344, 444, 778 keV photons emitted from Eu-152 have been determined by using HPGe detector. Effective atomic numbers (Z(eff)) and electron densities (N-e) of the ores calculated in the selected energies.. The agreement of measured values of mu/p, Z(eff) and N-e with theoretical calculations is quite satisfactory. Mass attenuation coefficients were found to be highest for barite. The Z(eff) and N-e values for barite are maximum, for serpentine are minimum. Gamma ray energy absorption (EABF) and exposure buildup factors (EBF) were computed for ore samples using the five-parameter Geometric Progression (G-P) fitting method in the energy range 0.015-15 MeV for penetration depths up to 40 mean free path. Variations of EABF and EBF with incident photon energy and penetration depth were also investigated. It has been observed that among the selected ore samples, barite has lowest values for EABF and EBF in the intermediate energy region. Buildup of photons is more for serpentine. Exposure buildup factors (EBF) of given ores were compared with lead, steel-magnetite concrete (SM), concrete and bismuth borosilicate glass (BBS) with %20 mol Bi2O3. Barite is superior in terms of shielding properties among the other ore samples. The present study may be useful for radiation shielding applications. (C) 2015 Elsevier Ltd. All rights reserved.