Determination of aluminium concentration in copper–aluminium alloys using  -ray transmission techniques A.H. El-Kateb*, R.A.M. Rizk, A.M. Abdul-Kader Physics Department, Faculty of Science, Helwan University, Ain Helwan, PN. 11795, Cairo, Egypt Received 16 May 2001; received in revised form 16 July 2001; accepted 17 July 2001 Abstract Disk foils of copper aluminium alloys of 7.07 cm 2 and thickness from 0.39 to 0.83 cm are used as targets for  -rays photons of energies 81 and 356 keV. Single and dual energy trans- mission techniques were applied to determine the concentration of aluminium as a minor component. It is concluded that aluminium concentration can be determined with an accuracy of more than or equal to 98.53 and 99.09% in the cases of single and dual energy gamma-ray transmission techniques, respectively. The results of the two techniques are compared with results from chemical analysis. Discrimination between single and dual energy methods depends on the error due to the counting rate and mass thickness. # 2002 Published by Elsevier Science Ltd. 1. Introduction Although several methods are used to determine an unknown component in a material (for example ash in coal, uranium in solution, PbS in ore products) depending on atomic and nuclear techniques, such as X-ray, neutron activation analysis, and  -ray technique, the latter is the accurate and the most economic.  - ray techniques generally give adequate accuracy for the wanted component and are useful for industrial plant control, much simpler and less expensive than the X-ray and the neutron activation analysis. They have widely used Whittacker et al. (1966), Annals of Nuclear Energy 29 (2002) 991–1002 www.elsevier.com/locate/anucene 0306-4549/02/$ - see front matter # 2002 Published by Elsevier Science Ltd. PII: S0306-4549(01)00087-1 * Corresponding author. E-mail address: ahelkatel@frcu.eun.eg (A.H. El-Kateb).