Separation of weighable amounts of ¹⁰Be from proton irradiated graphite

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.