HIs Role in the Development of Nuclear Chemistry
After Geiger’s college education, he found employment at the University of Manchester in England where he began working on projects involving nuclear chemistry with the previously mentioned Ernest Rutherford. In 1910, after working with Rutherford for some time, Geiger determined that the radioactive decay of two different uranium isotopes released two alpha particles. In partnership with Ernest Marsden, created a machine that detected the positive charge of these alpha particles in the form of scintillations after the particles were passed through gold foil.
However, as their experiment showed, many of the alpha particles didn’t pass through the foil, but rather they were deflected off of it. Both Geiger and Rutherford planned on finding a way to “measure these scintillations... accurately,” but this was determined to be rather difficult (“June 1911: Invention…”). Despite this challenge, Geiger invented an alpha particle counter in 1911; this device was known as the Geiger Counter. This machine counted radioactive particles through an electric charge that was sent through a wire (which functioned as the anode) in a tube containing gas (which functioned as the cathode). This charged then caused the gas to ionize and activate electrons. These passing radioactive particles would then be noted by an electrometer. The Geiger Counter significantly contributed to nuclear chemistry, as it developed a feasible way to detect and measure different forms of ionizing radiation.
Hans Geiger then joined James Nuttall to further the findings on the alpha particle, which led to their finding of the Geiger-Nuttall law in 1912, the same year that Geiger was named the administrator of the German National Institute for Science and Technology. This principle acknowledges that there is a correlation “between the logarithm of the range of alpha particles and the radioactive time constant” (Bellis). In other words, this law claims that the lifespan of an isotope is related to how much energy the released alpha particles contain; isotopes with long life spans release weaker alpha particles than those with short life spans. Also in this year, Geiger used the Geiger Counter to discover that the alpha particles is the nuclei of atoms of helium. This device would also be used to aid Rutherford in his theory about atoms.