A new beam-velocity-independent data analysis is used in a zero-field quantum-beat measurement for the determination of the magnetic-dipole hyperfine-interaction constants of the $3{}_{}{}^3{}_{}{}^{}P$ and $4{}_{}{}^3{}_{}{}^{}P$ states of ${}_{}{}^3{}_{}{}^{}\mathrm{He}$.

• Received 26 June 1972

DOI:https://doi.org/10.1103/PhysRevLett.30.155