Appearance of Pb-210 needle for diffusion cloud chamber

Appearance of needle for cloud chamber

The following image is a sample image of the radioactive source needle that is used for the diffusion cloud chamber.  The deposited material on the top of the needle is the Pb-210 containing material and some of the products from the deposition process.  Due to the radioactive decay of this material and the highly reactive species generated during this process, some corrosion may be present.  This is normal and is unavoidable due to the reactivity of decay products in contact with and in proximity to the needle.