Measuring Radioactivity from Cathode Ray Tubes

Old cathode ray tubes (CRT), which still may be found in some lab or in old equipment storage, are among the everyday objects which exhibit a small amount of radioactivity. This can be investigated by the use of a Geiger counter, trying to understand whether the emitted radiation is able to pass through thin layers of absorber material. Experimental activities with CRT and a Geiger counter are here discussed, with typical analyses of the results.