Measurement of atomic-hydrogen spin-exchange parameters at 0.5 K using a cryogenic hydrogen maser

Journal Article · Fri Mar 01 04:00:00 EST 1996 · Physical Review A

DOI:https://doi.org/10.1103/PhysRevA.53.1589· OSTI ID:279024

Hayden, M E; Huerlimann, M D; Hardy, W N ^[1]

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1. Department of Physics, University of British Columbia, Vancouver, British Columbia, V6T1Z1 (CANADA)

Using a cryogenic hydrogen maser, suitably modified to have electronic control of both the resonance frequency and the quality factor of the external cavity, we have measured a number of spin-exchange parameters for an atomic-hydrogen (H) gas at a temperature of 0.5 K. These results are relevant to the ultimate achievable frequency stability for cryogenic H masers and, when coupled with accurate calculations of the spin-exchange parameters, serve as a sensitive test of the H-H interatomic potentials. We find evidence for a frequency shift not predicted by semiclassical theories of spin exchange. In the context of a fully quantum mechanical hydrogen-atom spin-exchange theory [B. J. Verhaar {ital et} {ital al}., Phys. Rev. A {bold 35}, 3825 (1987) and J. M. V. A. Koelman {ital et} {ital al}., Phys. Rev. A {bold 38}, 3535 (1988)], this frequency shift is attributed to the influence of hyperfine interactions during spin-exchange collisions. Our findings are generally in agreement with these predictions; however, the sign of the hyperfine-induced frequency shift appears to differ from theory. {copyright} {ital 1996 The American Physical Society.}

• OSTI ID: 279024
• Journal Information: Physical Review A, Journal Name: Physical Review A Journal Issue: 3 Vol. 53; ISSN PLRAAN; ISSN 1050-2947
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
HYDROGEN
INTERATOMIC FORCES
MASERS
POTENTIALS
SPIN EXCHANGE
TEMPERATURE RANGE 0000-0013 K