Kalker tozu, kırklareli mermerleri ve alüminyum için gama zayıflatma katsayısının hesaplanması
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Dosyalar
Tarih
2017
Yazarlar
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Yayıncı
Trakya Üniversitesi Sosyal Bilimler Enstitüsü
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Tüm canlılar kozmik ve karasal radyasyondan oluşan doğal ve aynı zamanda yapay radyasyona maruz kalırlar. Karasal radyasyona, toprak, su, hava ve bitkilerdeki radyasyon da katkıda bulunmaktadır. Yapay radyoaktivite kaynaklarının başında ise nükleer deneyler ve tedavideki uygulamaların sonucunda yayılan radyasyon gelmektedir. Bu nedenle, radyolojik ölçümler, çevresel ve özellikle; nükleer güçsantrallerinin kullanımı, detektörlerin üretimi, hızlandırıcılar ve diğer nükleer araştırmaları içeren nükleer çalışmalar için önemlidir (Glenn, 2010). Üç tip radyoaktivite; alfa (?), beta (ß) ve gama (?) önemlidir. Bunlardan gama yüksüz ve kütlesiz olduğundan, maddeden kolayca geçmekte ve nükleer çalışmalarda bu fotonlara karşı zırhlama problemi ortaya çıkmaktadır (Glenn, 2010). Kullanılan malzemeler için, çeGitli enerjilerde, gama soğurma katsayıları bilinmelidir. Materyalden geçen gama radyasyonuna ait diğer parametrelerde bilinmelidir Bunlar kütle zayıflatma katsayısı, yarı değer kalınlığı, onda bir değer kalınlığı Fotonların madde ile etkileşmesi sonucu, fotoelektrik olay (PE), Compton (C) ve çift oluşumu (PP) olayları gerçekleşmektedir. Bu nedenle toplam soğurma katsayısıPE C PP ? ? ? ? ? ? ? (1) denklemi ile hesaplanır. Bu katsayının birimi, belli bir enerji için, soğurucu malzemenin birim uzunluğuna karşılık olarak, uzunluğun tersi ile (cm-1) ile verilir (Stabin 2007). Bu çalışmanın amacı, seçilen malzemelerin, çeşitli şartlarda, gama soğurma katsayılarını deneysel ve teorik olarak belirlemektir. Kırklareli mermerinin gama zayıflatma katsayıları farklı enerjiler, geometrilerle hesaplanmış kalker tozu alüminyum numuneleri ile karşılaştırılmıştır. Deney seti hazırlandıktan sonra Beer-Lamberts ii Kanunu; ile soğurma katsayısı hesaplanacaktır, burada x; örneğin kalınlığı, I0; belirlenen enerjide, soğurma söz konusu olmadan, gama ışınının yoğunluğunu gösteren sayım sayısı, I; soğurmadan sonra, gama ışınının yoğunluğunu gösteren sayım sayısıdır. (Medhat, 2009) Araştırmalar sırasında kolaylık sağlayan diğer zayıflatma katsayısı olan kütle zayıflatma katsayısına da bakılmıştır. Kütle zayıflatma katsayısını (cm-2/g) denklemi ile hesaplamaktayız. Bu çalışmada kalker tozu, Kırklareli mermer örnekleri ve alüminyum, Cs-137, Co-60 radyoaktif kaynakları ile incelenecektir. Gama soğurma katsayısı, gama geçiş tekniği ile deneysel olarak tespit edilip, gama soğurma ve kütle soğurma katsayıları belirlenecektir. Teorik kütle soğurma katsayısının hesabı için XCOM bilgisayar programı kullanılacaktır (Buyuk, Tugrul, 2014; Berger vd., 2014). Deneysel ve teorik sonuçlar karşılaştırılacak ve literatürdeki sonuçlar ile tartışılacaktır.
All living beings are exposed to radiation from natural sources such as cosmic rays, terrestrial radionuclides in soil, water, air and plants; and from artificial sources such as radioactivity from nuclear experiments and medical applications. Therefore radiological measurements and radiation protection are important for environment and nuclear studies specifically for nuclear power plants, detector manufactures, accelerators, and other increasing use of radioactive isotopes in different fields, (Glenn 2010). The shielding is widely and effectively used method for protecting from radiation, in which naturally and composites materially are used. The aim of this work is to determine,first time experimental and theoretical values of gamma-ray attenuation coefficients of Kırklareli marble for different conditions- photon energies, geometric locations. And the same investigation is carried out for limestone and aluminium to compare. It should be important to study the different parameters; mass attenuation coefficient, half value layer, tent value layer, related to the passage of gamma radiation from material. Since we get the fraction energy scattered or absorbed of gamma radiation from investigated attenuation parameters, the coefficient becomes a necessary parameter for study of interaction of radiation. Three types of radiations namely alpha (?), beta (ß) and gamma (?) are important. Since a ?-ray has no charge and mass, it can easily penetrate into matter, and thus the problem of shielding against these photons in nuclear science arises. The attenuation coefficient for ?-ray is determined accordingly different energetically in the medium of interest. The mechanisms of interaction between photons and medium are; Photoelectric (PE), Compton (C), and Pair Production (PP). So we are able to write that the total attenuation coefficient (µ) as PE C PP ? ? ? ? ? ? ? . iv The units of these coefficients is inverse length (e.g., cm-1), since it is defined as the probability of a radiation interacting with atoms per unit path length in attenuating medium (Woods, 1982). After the experimental assembly was prepared, the linear attenuation coefficients were calculated by using Beer-Lamberts Law: In this equation, I0 is the number of counts regarding the intensity of gamma-ray photons, at a specific energy, without attenuation. I also, is the number of counts of gamma-ray photons that penetrated trough the absorber with attenuation of the sample, x is thickness of the sample. In this study marble from Kırklareli, aluminium and limestone powder were investigated against Cs-137, Co-60, gamma radioisotope sources. The gamma attenuation properties of the interested materials was used to investigate with the experiments due to gamma transmission technique. The another attenuation coefficient can be defined for more convenience during investigation. The mass attenuation coefficient is calculated as (cm2/g), that is independent of the mass. Linear and mass attenuations of the samples are measured. Theoretical mass attenuation coefficient values were obtained by using XCOM computer code, due to (Berger and Hubbell, 1987) named XCOM: Photon cross section on a personal computer. The experimental results and theoretical results will be able to compared and the obtained result will be evaluated with using literature (Buyuk and Tugrul, 2014; Berger et al, 2014).
All living beings are exposed to radiation from natural sources such as cosmic rays, terrestrial radionuclides in soil, water, air and plants; and from artificial sources such as radioactivity from nuclear experiments and medical applications. Therefore radiological measurements and radiation protection are important for environment and nuclear studies specifically for nuclear power plants, detector manufactures, accelerators, and other increasing use of radioactive isotopes in different fields, (Glenn 2010). The shielding is widely and effectively used method for protecting from radiation, in which naturally and composites materially are used. The aim of this work is to determine,first time experimental and theoretical values of gamma-ray attenuation coefficients of Kırklareli marble for different conditions- photon energies, geometric locations. And the same investigation is carried out for limestone and aluminium to compare. It should be important to study the different parameters; mass attenuation coefficient, half value layer, tent value layer, related to the passage of gamma radiation from material. Since we get the fraction energy scattered or absorbed of gamma radiation from investigated attenuation parameters, the coefficient becomes a necessary parameter for study of interaction of radiation. Three types of radiations namely alpha (?), beta (ß) and gamma (?) are important. Since a ?-ray has no charge and mass, it can easily penetrate into matter, and thus the problem of shielding against these photons in nuclear science arises. The attenuation coefficient for ?-ray is determined accordingly different energetically in the medium of interest. The mechanisms of interaction between photons and medium are; Photoelectric (PE), Compton (C), and Pair Production (PP). So we are able to write that the total attenuation coefficient (µ) as PE C PP ? ? ? ? ? ? ? . iv The units of these coefficients is inverse length (e.g., cm-1), since it is defined as the probability of a radiation interacting with atoms per unit path length in attenuating medium (Woods, 1982). After the experimental assembly was prepared, the linear attenuation coefficients were calculated by using Beer-Lamberts Law: In this equation, I0 is the number of counts regarding the intensity of gamma-ray photons, at a specific energy, without attenuation. I also, is the number of counts of gamma-ray photons that penetrated trough the absorber with attenuation of the sample, x is thickness of the sample. In this study marble from Kırklareli, aluminium and limestone powder were investigated against Cs-137, Co-60, gamma radioisotope sources. The gamma attenuation properties of the interested materials was used to investigate with the experiments due to gamma transmission technique. The another attenuation coefficient can be defined for more convenience during investigation. The mass attenuation coefficient is calculated as (cm2/g), that is independent of the mass. Linear and mass attenuations of the samples are measured. Theoretical mass attenuation coefficient values were obtained by using XCOM computer code, due to (Berger and Hubbell, 1987) named XCOM: Photon cross section on a personal computer. The experimental results and theoretical results will be able to compared and the obtained result will be evaluated with using literature (Buyuk and Tugrul, 2014; Berger et al, 2014).
Açıklama
Anahtar Kelimeler
Gamma Attenuation, NaI(Tl), Scintillation Dedector, Kırklareli Marbles, Gama Zayıflatma Katsayısı, Kırklareli Mermerleri, NaI(Tl) Sintilasyon Dedektörü
