Spin-exchange frequency shifts in cryogenic and room-temperature hydrogen masers

J.M.V.A. Koelman, S.B. Crampton, H.T.C. Stoof, O.J. Luiten, B.J. Verhaar

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55 Citations (Scopus)


We have calculated the spin-exchange shifts of the ground-state ¿mF=0 transition of a gas of hydrogen atoms in zero magnetic field from zero temperature up to temperatures of 1000 K. Taking into account the hyperfine interaction during spin-exchange collisions we find shifts nonlinear in the atomic linewidth and not compensated for by the usual methods of tuning the microwave cavities of oscillating hydrogen-maser frequency standards. At room temperatures these shifts affect the H-maser stability at the level of d¿/¿¿10-15. At cryogenic temperatures these shifts are large compared to the potential thermal instabilities of liquid-helium-lined hydrogen masers. A detailed study of these nonlinear shifts reveals several ways to reduce these new sources of frequency instability.
Original languageEnglish
Pages (from-to)3535-3547
Number of pages13
JournalPhysical Review A: General Physics
Issue number7
Publication statusPublished - 1988


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