Separation of weighable amounts of 10 Be from proton irradiated graphite.

Large amounts of10 Be are produced at the PSI muon production facility by high-energy proton spallation in polycrystalline graphite. For the extraction of10 Be 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 product3 H2 O was trapped in 3 water bubblers connected in series. The remainder, a white hygroscopic solid material mainly consisting of7 Li2 O,9/10 BeO and10/11 B2 O3 , was dissolved in HF and subsequently purified by ion exchange chromatography. Radioactive impurities such as22 Na,44 Ti,54 Mn,60 Co,101 Rh,133 Ba and172 Hf have been separated from the final product. The purified material represents a mixture of approx. 6.5mg9 Be and 3.5mg (3.3MBq)10 Be. It is ready to be used for scientific investigations requiring large amounts of this precious isotope.