Layer-splitting technique for testing the recursive scheme for multilayer shields gamma ray buildup factors. (February 2016)

• Record Type: Journal Article
• Authors: Alkhatib, Sari F.; Park, Chang Je; Jeong, Hae Yong; Lee, Yongdeok
• Is Part Of: Annals of nuclear energy. Volume 88(2016:Feb.)
• Page Start: 24
• Page End: 29
• Publication Date: 2016-02
• Subjects: Buildup factor -- Iterative scheme -- Layer-splitting technique -- Multilayer shields -- Point kernel -- Recursive scheme; Nuclear energy -- Periodicals; Nuclear engineering -- Periodicals; 621.4805
• DOI: 10.1016/j.anucene.2015.10.032
• Languages: English
• ISSNs: 0306-4549

Abstract

Highlights: A simple formalism is suggested for the recursive approach and then it is used to produce buildup factors for certain multilayer shields. The newly layer-splitting technique is implemented on the studied cases for testing the suggested formalism performance. The buildup factors are generated using cubic polynomial fitting functions that are produced based on previous well-acknowledge data. Abstract: This study illustrates the implementation of the newly suggested layer-splitting testing technique. This technique is introduced in order to be implemented in examining suggested formalisms for the recursive scheme (or iterative scheme). The recursive scheme is a concept used in treating and producing the gamma ray buildup factors in the case of multilayer shields. The layer-splitting technique simply enforces the scheme to treat a single layer of one material as two separated layers with similar characteristics. Thus it subjects the scheme to an abnormal definition of the multilayer shield that will test its performance in treating the successive layers. Thus, it will act as a method of verification for the approximations and assumptions taken in consideration. A simple formalism was suggested for the recursive scheme then the splitting technique was implemented on it. The results of implementing both the suggested formalism and the splitting technique are then illustrated and discussed. Throughout this study, cubic polynomial fitting functions were used to generate the data of buildup factors for the basic single-media that constitute the multilayer shields understudy. This study is limited to the cases of multiple shields consisting of repeated consecutive thin layers of lead–water and iron–water shields for 1 MeV gamma rays. The produced results of the buildup factor values through the implementation of the suggested formalism showed good consistency with the Monte Carlo simulation results of Lin and Jiang work. In the implementation of the introduced technique, the deviation caused by the splitting of the layers in the multilayer shields understudy did not reach extreme limits and remains well below 16%. The proposed formalism showed good stability with the introduced changes, at least within the frame of this study. The implementation of the layer splitting technique was easy and it can be conducted on many other formalisms of the recursive approach.