The Radioactivity of Thorium Incandescent Gas Lantern Mantles

The use of thorium in providing the intense white luminescence emitted from gas mantles, has a history some 130 years, initial application pre-dating by several decades large-scale urban electric lighting. Accordingly, thoriated mantle proved itself to be enormous utility, remaining popular more rural areas well into 20th century, continuing enjoy campsites and street night markets lanterns until today. discovery 1828 preceded radioactivity, with subsequent little appreciation initially any potential harm exposure radioactivity. Study been made herein small quantities five different types mantle, all purchased online devoid control measures. Several approaches were used concerning 232Th activity dose consequence. First, was estimated using an HPGe detector, sample M5 greatest at 1.25 × 104 Bq, exceeding exemption limit for mantle. Compared M5, samples M1 M4 low 5.1 ± 1.31 16.33 1.92 Bq. Moreover, content constituted 50% mass, somewhat greater than previous literature values. equivalent rate on surface single found 0.68 µSv/h, while pack six level 1.9 µSv/h. Monte Carlo simulation codes have obtain organ effective rates, close contact (10 cm) unlit being thymus, µSv/h 0.62 male female phantom respectively. packages mantles potentially giving rise non-negligible doses, incorporation controls sale such items national radiation protection legislation would seem worthy consideration.