There are some electronic tubes that contain small quantities of radioactive materials to enhance the internal ionization processes. Such tubes have been used in the 20th century mostly in radar technology. Using a Geiger dosimeter, I have created a top of the tubes in my collection, based on their measured activity.
Some of the radioisotopes used in these tubes are Cesium-137, Cobalt-60, Radium-226, Krypton-85. Because of the small quantities involved and the short half-life, Co-60 and Kr-85 can’t be detected outside the corresponding tubes, because these devices are old and with the passing time the radioactive atoms have decayed to stable elements.
Being mostly used in RADAR technology, the radioactive elements have been added to increase the electronic response by improving the internal ionization processes.
The film shows the following tubes, in order: 11TN40, MA340, 313CD, JAN-8370, JAN-4C35, TG-77, EII-43-100, JAN-346B, 1B26, 1B22