Determination of uranium and thorium in Egyptian monazite by gamma-ray spectrometry

A sample of pure monazite prepared from beach sands, from the Abu-Khashaba area near Rosetta, has been investigated by means of passive and active measurement techniques. The natural gamma-rays emitted from the sample under investigation as well as those emitted following neutron activation are measured. The sample and the standards used were prepared and simultaneously irradiated in a neutron flux of the order 10(3) n cm(-2) s(-1) using the Egyptian Research Reactor-1 (ET-RR-1). The spectrometry facilities of the nuclear physics laboratories, specifically, the hyper-pure germanium detection systems and some special computer programs, were used for the measurements. The gamma-ray peaks at 270.2, 583.1, 911.2, 968.8 and 2204.2 keV for thorium and uranium daughters in passive measurements and the gamma-ray peaks at 311.8 and 277.6 keV for active measurements are used for estimation of thorium and uranium concentration values. The values obtained were between 46 +/- 2 and 59 +/- 3 ppm and 687 +/- 34 and 729 +/- 36 ppm for uranium and thorium, respectively. Copyright (C) 1997 Elsevier Science Ltd