How do you know when a particle is a beta emitter?

Answer 1

In the physics laboratory, an investigator might use a proportional detector or a scintillation counter to determine when a source is beta emitter. The problem is that a lot of "generalized" detectors (like a Geiger counter) are not specifically set up to detect only beta radiation, and that makes them unsuitable to the task of looking at just that one type of particulate emission. Let's look a bit further.

Beta radiation, which is emitted from a radioactive source that decays by beta emission, is either a positron or an electron. Either one is emitted in beta decay (but not both), and different isotopes decay by one type of beta decay or the other. Further, the beta particle emerges from the beta decay event with considerable kinetic energy. But beta radiation can be stopped by a sheet of paper, so the counter must be set up with a thin window that will allow beta radiation to penetrate it. By choosing an appropriate thickness of material, any alpha radiation will be stopped by the window, and beta radiation will penetrate it. Gamma rays will easily penetrate a window, but the design and construction (as well as the settings) of the detector will minimize any response to gamma radiation.

It might be possible to test the source material to determine what element it is. By knowing the element and its "history" as such, the particular isotope of that element might be determined. The isotopes of the elements have been researched, and a good table of nuclides will allow an investigator to determine whether the isotope being investigated is one that undergoes beta decay.