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SiO(2) Encapsulation of Radioisotope Sources

IP.com Disclosure Number: IPCOM000051945D
Original Publication Date: 1981-Apr-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Hicks, WW: AUTHOR [+2]

Abstract

A process is described for the elimination of contamination caused by radioactive material through touch or diffusion without substantial energy loss of emitted particles. This is achieved by initially sputtering a layer of SiO(2) without resputtering on the radioactive material an then sputtering a layer of SiO(2) with resputtering on the initial layer. Alternatively, the initial layer of SiO(2) may be deposited on the radioactive material by chemical vapor deposition, and this followed by the sputtering of a layer of SiO(2) with resputtering.

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SiO(2) Encapsulation of Radioisotope Sources

A process is described for the elimination of contamination caused by radioactive material through touch or diffusion without substantial energy loss of emitted particles. This is achieved by initially sputtering a layer of SiO(2) without resputtering on the radioactive material an then sputtering a layer of SiO(2) with resputtering on the initial layer. Alternatively, the initial layer of SiO(2) may be deposited on the radioactive material by chemical vapor deposition, and this followed by the sputtering of a layer of SiO(2) with resputtering.

Radioactive sources and, in particular, alpha-particle sources require some form of encapsulation in order to prevent contamination of materials or personnel which may come into contact with or handle such sources. This encapsulation is typically performed by evaporating or sputter depositing a metallic coating over the radioactive film. The metal used for coating is normally gold for sputter deposition (~5000, angstroms). Titani may also be used but has to be reasonably thick (>/- 40,000 angstroms) in order prevent pinholes and leakages. As a result, when the emitted radiation is in the form of alpha-particles, there is a substantial energy loss and straggling in the film (up to 1-2 MeV).

By replacing the metal film coating with sputtered SiO(2), encapsulation may be achieved with thin films (e.g., 800 angstroms to 5,000 angs which results in very little energy loss for 4-6 MeV...