Radioactivity in some gas-flow lantern mantles produced by different manufacturers

Groups of gas-flow lantern mantles of different manufacturers were subjected to radiometric investigation to evaluate the radiological hazards arising from their usage. Interest was given to the long-lived radionuclides found, which were the α-emitting nuclides of thorium and 228Ra. Thorium isotopes were analyzed by α-spectrometry whereas 228Ra was analyzed by γ-spectrometry. The results show that mantles from different manufacturers contain mainly natural thorium with levels that fluctuate over a very wide range, from 350 to 4560 Bq/mantle. For the same manufacturer, thorium levels vary strongly in mantles of different batches and even from the same batch. On burning the mantle, a 10–20% reduction in the thorium activity takes place in the first few minutes. The mantle containers were almost free from significant thorium contamination. Results are given and discussed in detail.