are predominantly used for professional lighting i. e. in shops and cinemas. Doses from routine use of these lamps is estimated to be insignificant.
Radioactivity in antiques Radioactive materials were used in a range of products over the years, including watches, dials, ceramics and glassware. Radioluminescent materials, including Radium-226, tritium and Promethium-147 have historically been used on watches, dials and other timepieces. It is estimated that the maximum annual dose to someone wearing a watch containing radioactivity would be no more than a few tens of μSv. Natural uranium compounds have been historically used in Vaseline glass, or in glazes on the surface of tiles or tableware to produce a variety of colours. Estimated doses to collectors handling such items are trivial.
Electronic components Radioactive electronic valves were once widely used in radar and telecommunications equipment, although they have now been largely replaced by more advanced electronics. Such items may contain radioactive material in gaseous form, in which case exposure is only likely in the case of breakage with the dose from a single broken component estimated at a maximum of 2 μSv. The number of people who regularly handle such items is thought to be low.
Thoriated products Thoriated gas mantles use thorium compounds impregnated into the mesh to provide an incandescent property. In the UK they are still used by campers, although this use has declined significantly due to the development of LED lighting. Thorium may also be used in TIG welding electrodes. Conservative assessments of such products estimate that annual doses may potentially reach a few tens of mSv, but doses up to 1 mSv are more likely. The number of people who regularly handle such items is thought to be low.
Vintage clocks and watches with radioluminescent dials
Irradiated gemstones It has been known for many years that the colour of gemstones may be intensified or altered by irradiation. This process can happen naturally over a long period of time but using artificial irradiation to enhance colour, and therefore commercial value, is standard practice. Irradiation in this way can cause the stones to become slightly radioactive, but it is generally assumed that gems treated in this way are stored for a predetermined length of time to eliminate short-lived activation products prior to being released onto the open market.
A cabinet containing items made of Vaseline glass
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