That is very good of you to reply thank you so much. As you are an expert could you explain a post I saw on another forum which stated " It is the alpha recoil reaction that can destroy the thin coating over the source and allow source material to recoil out of the source." Apparently this caused a yellow discharge from someone's ionisation chamber which collected as a dust around the ionisation chamber, although the activity was 5 microcuries. " Could this occur in my smoke detector which is 27 years old and 0.9 microcuries. I was concerned as dust fell in my eye when I opened the detector and was worried when I read that the thin metal seal on the source can breakdown due to alpha particles over time and hence release the decay products and was worried this had came out of the ionisation chamber due to the age of my smoke detector. Thanks againPhinrich said:Good day.
As a Radiation Protection Specialist, with 30 years of experience, I can assure you that the risk to you, from fiddling with the Americium-241 source inside your smoke detector, is negligible. The quantity of radioactivty in such a detector is, in regulatory jargon, Exempt from being regulated. This means that the radiation dose, which anyone can be exposed to, by fiddling with the source, is considered too small to cause any harm. Yes, this does come from very detailed risk assessments which have considered ALL potential scenarios of "playing with the source" and the resultant radiation dose. Wherever you are living, if it was considered that the smoke detector could be harmful it would never have been sold to you as a member of the general public. I hope this puts your mind at ease. Of course, there's no harm in washing your hands after touching the source which I am sure that you did. If you didn't the potential radiation dose would still be negligible.