The sensor contains trace amount of 241 isotope.Americium emits particles and weak radiation. The particles are completely blocked by the sensor housing, and radiation freely passes through the housing, but it is quickly absorbed by the air (the maximum passing through the air is 15cm) due to the very low energy of about 60 keV.This is a good source to check the gamma-ray sensitive Geiger counter. If you have this type of counter, it is impossible to test it with other sources that only emit beta particles.It can also be used to test the gamma spectrometer.Add a beautiful "hot" item to your collection, which will emit alpha and gamma rays.Geiger counter based on SBM-20 electron tube shows that the source counts 140 times per minute (correspondingly, about 80 uR/h or 0.8 uSv/h) when gamma filter is applied.Specifications:1) Ionization source characteristics and radiation safety performance:2) The ionization chamber is equipped with Am-241 ionizer with high performance and low activity.3) Ionization source activity: 0.5 UCI (18 kbq) 0.8 UCI 10% (30 kbq 10%)4) Ionization source A spectrum: peak value: 4.5 MeV 10%, FW HM.