This sensor contains tiny amount of Americium 241 isotope.<br> Americium emits for alpha particles and weak gamma radiation, for alpha particles completely blocked by the casing of the sensor, gamma radiation however freely passes through the casing but due to very low energy around 60 keV quickly absorbed by (maximum run through 15cm).<br> It is a great source for checking gamma only sensitive counters, if you have such type of counter it will be impossible to test it with other sources which emit beta particles only.<br> It could be used to test gamma spectrometers as well.<br> Add a nice "hot" piece to your collection which emits for alpha and gamma radiation.<br> SBM-20 tube based counter indicates 140 Counts per minute from this source with gamma filter applied (approximately 80 uR/h or 0.8 uSv/h accordingly).<br> <br> Specifications:<br> 1) Ionization source characteristics and radiation safety performance:<br> 2) The ionization chamber fitted with a high performance and low activity of Am-241 ionization<br> 3) Ionization source activity: 0.5uCi ( 18KBq ) 0.8uCi10% ( 30KBq10% )<br> 4) Ionization source a spectroscopy: peak: 4.5MeV 10%, FW HM