Charles,
I tried a magnet on one of my Am241 buttons.? It was weakly magnetic.? Assuming it is Stainless Steel, this points to an Austenitic class (like 304 or 316) and that means it has both Cr and Ni in the composition.? 304 is around 18% Cr and 8% Ni , 314 is about the same Cr, but 10-14% Ni with a little Mo thrown in.? There are others, but these two are very common.? I don't know if you would see Ni interference with a long Am241 scan or not.
Strongly magnetic stainless steels are a Ferritic/Martensitic and have Cr but no Ni.? These are 400 series, you see this used often in knives.
Mike L.
Mike L.