Radioactive Cup Source: Strontium-90 - 5µCi (185 kBq) - Cup TypeThe active material is enclosed in metal foil fixed in a cylindrical mount provided with a stem of 4mm diameter. The foil is further protected from accidental damage by a wire gauze cap over the open 'window' of the mount. The nature and strength of each source is clearly engraved on its mount and it is also colour coded for identification. Each is supplied in a small lead 'castle' in a suitably labelled MDF storage box (100mm x 75mm x 65mm). A data sheet is enclosed with each.5µCi (185 kBq) of Strontium-90 in equilibrium with its daughter nuclide Yttrium-90 incorporated in a silver disc allowing the major proportion of the Beta radiation to escape.Emissions: betaHalf-life: 28 years (strontium) 64 hours (yttrium)Colour code: YellowRequirements for purchase:Welsh state schools need a permit from the Welsh Assembly.Scottish schools require approval from the Scottish Government Education Directorate.Schools in Northern Ireland require a DENI permit.State schools in England do not require a Letter of AuthorisationIndependent schools in England Wales & Northern Ireland do not require a Letter of AuthorisationUnavailable for export outside of the UK