Doğal Siyah Obsidyen Cevherleri İçin Yığılma Faktörlerinin Belirlenmesi

Bu çalışmada, Artvin ve Van yöresinden çıkarılan doğal siyah obsidyen cevherleri kullanılmıştır. Her iki obsidyen cevherinin kimyasal kompozisyonları, sırasıyla bir enerji ayırımlı X-ışını floresan spektrometresi (EDXRF) ile bir dalga boyu ayırımlı X-ışını floresan spektrometresi (WDXRF) kullanılarak belirlenmiştir. Bu doğal örneklerin gama-ışını enerji soğurma yığılma faktörleri (EABF) ile doz yığılma faktörleri (EBF), 0,015-15 MeV foton enerji aralığında ve 0,5-40 mfp derinlik bölgesinde 16 çeşit nüfuz etme derinliği için hesaplanmıştır. EABF ve EBF değerlerini hesaplamak için beş-parametreli geometrik dizi (G-P) yaklaşımı ve ANSI/ANS-6.4.3-1991 standart veri arşivi kullanılmıştır. EABF ve EBF değerleri, gelen foton enerjisinin ve nüfus etme derinliğinin bir fonksiyonu olarak incelenmiştir. İki örnek için elde edilen sonuçların birbirleriyle uyumlu olduğu bulunmuştur. Bu uyumluluk, her ne kadar kimyasal kompozisyonlarda farklılıklar olmasına rağmen, iki örnekte de yer alan silisyum dioksit (SiO2) kristalinin baskınlığından ileri geldiği söylenebilir. Ayrıca obsidyen cevherlerinin EABF ve EBF değerlerinin gelen foton enerjisinin ve nüfus etme derinliğinin değişimiyle önemli bir şekilde değiştiği bulunmuştur. Bu değişimler, farklı enerji bölgelerinde farklı foton etkileşim süreçlerinin hâkimiyeti nedeniyledir. Bu çalışmada sunulan sonuçların, doğal siyah obsidyen cevherlerinde soğurulan radyasyon dozunun değerlendirilmesinde yararlı olacağı beklenilmektedir

Determination of Build-up Factors for Natural Black Obsidian Ores

Natural black obsidian ores extracted from Artvin and Van were used in this study. The chemical compositions of both obsidian ore were determined using an energy-separated X-ray fluorescence spectrometer (EDXRF) with a wavelength-separated X-ray fluorescence spectrometer (WDXRF), respectively. The gamma-ray energy absorption buildup factors (EBF) and dose buildup factors (EBF) of these natural samples were calculated for 16 types of penetration depths in 0,5-40 mfp depth region and the photon energy range of 0,015-15 MeV. The five-parameter geometric progression (G-P) fitting approximation and the ANSI/ANS-6.4.3-1991 (American National Standard) standard data archive were used to calculate EABF and EBF values. The EABF and EBF values were examined as a function of incident photon energy and penetration depth. The results obtained for the two samples were found to be consistent with each other. This compatibility can be said to be due to the dominance of the silicon dioxide (SiO2) crystals in both samples, although there are differences in the chemical composition. It has also been found that the EABF and EBF values of obsidian ores vary significantly with the change of the incident photon energy and the penetration depth. These changes are due to the dominance of different photon interaction processes in different energy regions. The results presented in this study are expected to be useful in assessing the radiation dose absorbed in natural black obsidian ores. © Afyon Kocatepe Üniversitesi

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