A modern example of Becquerel's plates |
 The image was produced with an X-ray film that was wrapped light-tight with aluminium foil. A box of thorium nitrate was placed under the wrapping, above a metal toy figure placed on the film, and left there for three days. Thorium is an alpha emitter; some of the decay products are beta emitters. The film probably is most sensitive to beta rays. Text and image adapted from ... |