The naturally occurring radioactivity of 'scalar energy' pendants and concomitant radiation risk

Forming part of a study of radiological risk arising from use of radioactive consumer products, investigation is made of pendants containing naturally occurring radioactive material. Based on use of gamma-ray spectrometry and Monte Carlo (MC) simulations, the study investigates commercially available 'scalar energy pendants'. The doses from these have been simulated using MIRD5 mathematical phantoms, evaluation being made of dose conversion factors (DCFs) and organ dose. Metallic pendants code MP15 were found to contain the greatest activity, at 7043 ± 471 Bq from 232Th, while glass pendants code GP11 were presented the greatest 238U and 40K activity, at 1001 ± 172 and 687 ± 130 Bq respectively. MP15 pendants offered the greatest percentage concentrations of Th, Ce, U and Zr, with means of 25.6 ± 0.06, 5.6 ± 0.005, 1.03 ± 0.04 and 28.5 ± 0.08 respectively, giving rise to an effective dose of 2.8 mSv for a nominal wearing period of 2000 h. Accordingly, these products can give rise to annual doses in excess of the public limit of 1 mSv.