A chemically durable glass containing a large amount of phosphorus is useful for in-situ irradiation of cancers. It can be activated to be a β-emitter with 14.3 days half-life by neutron bombardment. Microspheres of the activated glass injected into the tumors can irradiate the tumors directly with β-rays without irradiating neighboring normal tissues. In the present study, a P+ ion was implanted at 100 keV. There was little phosphorus present in the surface region, at least to a depth of 2.4 nm for doses of 5 × 1016 and 1 × 1017 cm-2, whereas an appreciable amount of it was distributed on to the glass surface and a part of it was oxidized for doses above 5 × 1017 cm-2. The glasses implanted with doses of 5 × 1016 and 1 × 1017 cm-2 released little both of the P and Si into water at 95°C, even after 7 days, whereas the glasses implanted to doses above 5 × 1017 cm-2 released appreciable amounts of these elements. At implantation energy of 20 and 50 keV, even doses of 5 × 1016 and 1 × 1017 cm-2, respectively, formed oxidized phosphorus on the glass surfaces and gave appreciable releases of the P and Si into the hot water. This indicates that a chemically durable glass containing a larger amount of phosphorus could be obtained if P+ ion implanted at higher energies is localized in a deeper region.
|Number of pages||5|
|Journal||Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms|
|Publication status||Published - 1997 Jan|
ASJC Scopus subject areas
- Nuclear and High Energy Physics