Introduction
Welcome to this Website that contains experiments on radioactivity, neutron activation and radioactive decay. The primary purpose of this site is to provide a resource about the neutron activation process and how it can be used to create and identify radioactive isotopes. These videos and accompanying data contain a range of introductory radioactive experiments for students. These experiments offer a unique opportunity for students in institutions such as high schools or small colleges where a neutron source would be impractical or impossible to maintain. In the event that others will find this material useful, this manual has been created to act as a guide for possible pre-lab learning, laboratory experiments, homework activities, and demonstrations. The random access nature of this page and streaming video allow teachers to easily show only those parts of the video that will work best in their course or laboratory as well as contain all relevant data, images, and documentation. The experiments described on this page and accompanying videos below were filmed in 2005 and turned into a DVD and then converted into this on-line resource in 2016.
These videos were initially created to address the imminent removal of a PuBe "Neutron Howitzer" source that had been at the University of Wisconsin - Whitewater since 1968. With the impending loss of this source, students would be unable to perform a standard introductory laboratory activity, namely measurements of the radioactive decay of activated silver quarters. In this experiment, silver US quarters (c. 1940) were irradiated with neutrons, causing the stable silver atoms to turn into unstable silver atoms. Students then used a Geiger counter apparatus to repeatedly measure the decay counts occurring during a certain length of time, then plotted the decay rate over time and determined the half-life of the unstable silver atom. Although this activity had been an instructive and popular laboratory exercise, maintaining a 5 Curie source for the sole purpose of this one laboratory had become too burdensome to justify continued possession (and payment of additional license fees.)
A video recording of this popular laboratory was made so that students would still be able to view the laboratory. Recording the neutron activation process and using computer data acquisition during the experiment shows situations that were logistically not possible in our ordinary laboratory activity. Recording a set of other appropriate elements, some of which have a longer half-life was also conducted. In this manner, a virtual laboratory set has been created. In a single standard laboratory session, or as a homework activity, different student groups can watch different, but similar, experiments, analyze the recorded data from the different elements, and determine the half-life for their assigned element. In addition, several different sources show different shielding characteristics for α, β, and γ emissions.