1999 Volume 48 Issue 8 Pages 514-521
Concentrations of 40K, thorium and uranium contained in the front glass of CRT (cathode ray tube) of television sets are measured by the γ-ray spectrometry. Although the obtained concentrations of thorium and uranium show the difference more than twice as much depending on the manufacturers, those of 40K 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.