Use of alpha spectrometry for analysis of U-isotopes in some granite samples

The present study aims to use the ??-spectrometry, at NMA. A radiochemical technique [1, 2] for analysis of U-isotopes was carried out for some granite samples from Gabal Gattar and El Missikat localities and also for some reference soil samples of IAEA. Several steps of sample preparation, radiochemical separation, and source preparation were performed before analysis. The concerned sample was leached by HNO₃, HF and H₂O₂ acids after ashing. The ashed sample was spiked with uranium tracer (²³²U) for chemical yield and activity calculation. Then uranium was extracted from the matrix elements with trioctylphosphine oxide (TOPO) and stripped with 1 M NH₄F/0.1 M HCl solution. The uranium fraction was purified by co-precipitation with LaF₃ to ensure complete removal of thorium and traces of resolution degrading elements. This was followed by a final clean-up step using an anion exchange. The pure uranium fraction was electrodeposited on a stainless steel disc from HCl/oxalate solution. The obtained results from the soil reference samples indicate general similarities between the techniques of ??-spectrometers of NMA, EAEA and IAEA for analysis of U-isotopes. The U-isotopes in the granite samples of high radioactivity levels need more attempts after dilution process to be in the limit detection of ??-spectrometry.