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Title: Measurement of a Long Electronic Spin Relaxation Time of Cesium Atoms in Superfluid Helium

Abstract

The longitudinal electronic spin relaxation time of Cs atoms optically polarized in superfluid helium (He II, 1.5 K) has been measured with special care to cope with a serious decrease in the number of Cs atoms in the observation region. This decrease, mainly caused by helium convection in introducing the atoms into He II by laser sputtering, was significantly reduced using a new atom implantation method. Combined with a careful correction for the number of atoms, we have determined the relaxation time to be 2.24(19) s or longer, roughly twice as long as that in solid He.

Authors:
; ;  [1]; ; ;  [2];  [3]
  1. Department of Physics, Graduate School of Science, Osaka University, Osaka 560-0043 (Japan)
  2. RIKEN, 2-1, Hirosawa, Wako-shi, Saitama 351-0198 (Japan)
  3. Institute of Physics, Graduate School of Arts and Sciences, University of Tokyo, Komaba, Tokyo 153-8902 (Japan)
Publication Date:
OSTI Identifier:
20777081
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review Letters; Journal Volume: 96; Journal Issue: 9; Other Information: DOI: 10.1103/PhysRevLett.96.095301; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 74 ATOMIC AND MOLECULAR PHYSICS; ATOMS; CESIUM; CONVECTION; DEPOSITION; ELECTRONS; HELIUM; HELIUM II; IMPURITIES; LASERS; RELAXATION TIME; SPIN; SPIN-LATTICE RELAXATION; SPUTTERING; SUPERFLUIDITY; TEMPERATURE RANGE 0000-0013 K

Citation Formats

Furukawa, T., Izumi, H., Shimoda, T., Matsuo, Y., Fukuyama, Y., Kobayashi, T., and Hatakeyama, A.. Measurement of a Long Electronic Spin Relaxation Time of Cesium Atoms in Superfluid Helium. United States: N. p., 2006. Web. doi:10.1103/PhysRevLett.96.095301.
Furukawa, T., Izumi, H., Shimoda, T., Matsuo, Y., Fukuyama, Y., Kobayashi, T., & Hatakeyama, A.. Measurement of a Long Electronic Spin Relaxation Time of Cesium Atoms in Superfluid Helium. United States. doi:10.1103/PhysRevLett.96.095301.
Furukawa, T., Izumi, H., Shimoda, T., Matsuo, Y., Fukuyama, Y., Kobayashi, T., and Hatakeyama, A.. Fri . "Measurement of a Long Electronic Spin Relaxation Time of Cesium Atoms in Superfluid Helium". United States. doi:10.1103/PhysRevLett.96.095301.
@article{osti_20777081,
title = {Measurement of a Long Electronic Spin Relaxation Time of Cesium Atoms in Superfluid Helium},
author = {Furukawa, T. and Izumi, H. and Shimoda, T. and Matsuo, Y. and Fukuyama, Y. and Kobayashi, T. and Hatakeyama, A.},
abstractNote = {The longitudinal electronic spin relaxation time of Cs atoms optically polarized in superfluid helium (He II, 1.5 K) has been measured with special care to cope with a serious decrease in the number of Cs atoms in the observation region. This decrease, mainly caused by helium convection in introducing the atoms into He II by laser sputtering, was significantly reduced using a new atom implantation method. Combined with a careful correction for the number of atoms, we have determined the relaxation time to be 2.24(19) s or longer, roughly twice as long as that in solid He.},
doi = {10.1103/PhysRevLett.96.095301},
journal = {Physical Review Letters},
number = 9,
volume = 96,
place = {United States},
year = {Fri Mar 10 00:00:00 EST 2006},
month = {Fri Mar 10 00:00:00 EST 2006}
}
  • The experiments of Tsakadze and Tsakadze on the relaxation of rotating He II after its container is given a sudden spin-up are discussed. It is shown that the relaxation times observed can be interpreted as Ekman times, analogous to the relaxation times in the corresponding situation with classical fluids if the quantum of vorticity kappa is taken as a characteristic kinematic viscosity. Further experiments to test and explore the analogy are suggested.
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  • Purpose: To investigate whether the direction of spin-lock field, either parallel or antiparallel to the rotating magnetization, has any effect on the spin-lock MRI signal and further on the quantitative measurement of T1ρ, in a clinical 3 T MRI system. Methods: The effects of inverted spin-lock field direction were investigated by acquiring a series of spin-lock MRI signals for an American College of Radiology MRI phantom, while the spin-lock field direction was switched between the parallel and antiparallel directions. The acquisition was performed for different spin-locking methods (i.e., for the single- and dual-field spin-locking methods) and for different levels ofmore » clinically feasible spin-lock field strength, ranging from 100 to 500 Hz, while the spin-lock duration was varied in the range from 0 to 100 ms. Results: When the spin-lock field was inverted into the antiparallel direction, the rate of MRI signal decay was altered and the T1ρ value, when compared to the value for the parallel field, was clearly different. Different degrees of such direction-dependency were observed for different spin-lock field strengths. In addition, the dependency was much smaller when the parallel and the antiparallel fields are mixed together in the dual-field method. Conclusions: The spin-lock field direction could impact the MRI signal and further the T1ρ measurement in a clinical MRI system.« less