Henry Michael Foley and Polykarp Kusch compared atomic magnetic resonance frequencies to determine the electron magnetic moment. They selected quantum states whose orbital angular momentum and spin contributions enter with different weights. Ratios of the measured frequencies revealed a departure from the simplest electron spin g-factor of exactly two. Comparing responses in the same magnetic field reduces dependence on absolute field calibration, turning a small spectral difference into a precision test of the magnetic response.[ref]
The Magnetic Moment of the Electron by Polykarp Kusch and Henry Michael Foley (1948). Abstract: compared gallium, indium and sodium states, measured resonance-frequency ratios and departure from the simple magnetic-factor values
A physicist and professor of physics at Columbia University.[ref]
https://findingaids.library.columbia.edu/pdf/cul-4078769.pdf. p. 3, creator name and Biographical / Historical note
The Kusch-Foley magnetic moment experiment describes his work with Polykarp Kusch. New to topics? Read the docs here!