Separation of weighable amounts of 10Be from proton irradiated graphite

Abstract

Large amounts of 10Be are produced at the PSI muon production facility by high-energy proton spallation in polycrystalline graphite. For the extraction of 10Be out of large amounts of carbon, pyrolysis followed by chemical purification has been performed. Approx. 270g of graphite from Target E92, which had received a total proton charge of 29 Ah between 2002 and 2005, have been burned at 1000°C in a stream of oxygen. The volatile radioactive oxidation product 3H2O was trapped in 3 water bubblers connected in series. The remainder, a white hygroscopic solid material mainly consisting of 7Li2O, 9/10BeO and 10/11B2O3, was dissolved in HF and subsequently purified by ion exchange chromatography. Radioactive impurities such as 22Na, 44Ti, 54Mn, 60Co, 101Rh, 133Ba and 172Hf have been separated from the final product. The purified material represents a mixture of approx. 6.5mg 9Be and 3.5mg (3.3MBq) 10Be. It is ready to be used for scientific investigations requiring large amounts of this precious isotope.