Concentrations of radioactive nuclides contained in the front glass of CRT and radiation doses

摘要

Concentrations of (40)-K, thorium and uranium contained in the front glass of CRT (cathode ray tube) of television sets are measured by the #gamma#-ray spectrometry. Although the obtained concentrations of thorium and uranium show the difference more than twice as much depending on the manufacturers, those of (40)-K are almost equal for all CRTs. The dose rates are estimated for the CRT. Even the dose rate for the highest concentration of thorium and uranium is smaller than about one-tenth of that for the background radiations. It is practically negligible at a distance larger than 20 cm from the surface of the front glass of CRT.