Precision measurements of the magnetic moment of the electron have been fundamental in the development and testing of quantum electrodynamics, and in searching for new forces or electron substructure. P. Kusch won the Nobel Prize in 1955 for early measurements of the electron magnetic moment, and ongoing measurements continue to probe for new physics beyond the Standard Model.
Electron Spin Resonance (ESR), also known as Electron Paramagnetic Resonance (EPR), is also very widely used in condensed-matter physics, chemistry, archaeology, geology, environmental science, biology, biochemsitry, pharmacology, medicine, and industry to study both static properties and dynamic processes in almost any system containing radicals (i.e. molecules with unpaired electrons). These applications include everything from detecting tumours to dating ancient material.
This experiment familiarizes students with the generation and transmission of microwave signals, and measures the magnetic moment of the electron in a solid free-radical.
(The experiment is currently located in MP226; last write-up revision: February 2010.)
Last updated on 5 February 2019