Measurement of thermal neutrons reflection coefficients for two-layer reflectors

S Azimkhani; F Zolfagharpour; F Ziaie

doi:10.1016/j.apradiso.2018.01.031

Measurement of thermal neutrons reflection coefficients for two-layer reflectors

Appl Radiat Isot. 2018 May:135:155-159. doi: 10.1016/j.apradiso.2018.01.031.

Authors

S Azimkhani¹, F Zolfagharpour², F Ziaie³

Affiliations

¹ Department of Physics, University of Mohaghegh Ardabili, P.O. Box 179, Ardabil, Iran. Electronic address: sara.azimkhani@gmail.com.
² Department of Physics, University of Mohaghegh Ardabili, P.O. Box 179, Ardabil, Iran. Electronic address: zolfagharpour@uma.ac.ir.
³ Radiation Application Research School, Nuclear Science & Technology Research Institute, P.O. Box 11365-3486, Tehran, Iran.

PMID: 29413831
DOI: 10.1016/j.apradiso.2018.01.031

Abstract

In this research, thermal neutrons albedo coefficients and relative number of excess counts have been measured experimentally for different thicknesses of two-layer reflectors by using ²⁴¹Am-Be neutron source (5.2Ci) and BF₃ detector. Our used reflectors consist of two-layer which are combinations of water, graphite, polyethylene, and lead materials. Experimental results reveal that thermal neutron reflection coefficients slightly increased by addition of the second layer. The maximum value of growth for thermal neutrons albedo is obtained for lead-polyethylene compound (0.72 ± 0.01). Also, there is suitable agreement between the experimental values and simulation results by using MCNPX code.

Keywords: Excess count; Polyethylene; Reflection; Saturation thickness; Thermal neutrons albedo; Two-layer reflector.