We now offer a selection of exempt quantity gamma sources encapsulated in standard size test tubes for use with well type radiation detectors. These sources are uncalibrated and of nominal activity. The isotope is deposited as a point source in the bottom of the tube and is then sealed with epoxy. Two tube sizes are stocked as standard, 13x100mm and16x125mm with other sizes available on special order. Isotopes may be selected from the following table. The cost of the Tube Source is $75 each, Europium 152 is $135 each. Tube source secondary calibration cost $100 per source.