Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Journal of Physics B Atomic Molecular and Optical Physics

Thermalization of rubidium atoms scattered from a low-temperature paraffin film

Yutaro Tanaka, K. Asakawa, Hiroaki Usui, A. Hatakeyama

Published Feb 9, 2026• 0 citations
Publisher

Abstract

Abstract With an objective to explore the surface interaction between alkali-metal atoms and an inert organic coating, we used an atomic beam to measure the velocity distribution of gaseous rubidium atoms scattered from a low-temperature tetracontane film. When the film temperature decreased from 300 K to 200 K, the number of scattered atoms did not change. At below 200 K, the number began to decrease until, finally, no scattered atoms were observable at 140 K. X-ray photoelectron spectroscopy at 160 K or below revealed rubidium atoms on the film surface. The temperature of the scattered atoms was the same as that of the film. Thermalization of scattered atoms at room temperature was reported previously, but this study is the first to report thermalization at low temperatures.

DOI
10.1088/1361-6455/ae43a4

Related papers

Scattering of an alkali-metal atomic beam on anti-spin-relaxation coatings

Naota Sekiguchi, A. Hatakeyama, Kazane Okuma +1 more

We performed scattering experiments using a rubidium (Rb) atomic beam on paraffin films and measured the angular and velocity distributions of scattered atoms. The paraffin films were prepared in various ways and characterized by atomic force microscopy and x-ray diffraction. The films exhibited various roughnesses and crystal structures. The paraffin films preserved the spin polarization of the scattered atoms. The measured angular distributions of all prepared films were consistent with Knudsen's cosine law. The velocity distributions were well fitted by Maxwell's distribution, characterized by a temperature much closer to the film temperature than to the atomic-beam temperature. We therefore concluded that the translational motion of the scattered atoms was thermalized with the paraffin films via single-scattering events.

arXiv:1807.02329•Physical Review A•Oct 29, 2018•17 citations

Measurement of the temperature dependence of dwell time and spin relaxation probability of Rb atoms on paraffin surfaces using a beam-scattering method

Kanta Asakawa, Yutaro Tanaka, Kenta Uemura +5 more

The scattering of Rb atoms on an antirelaxation coating was studied. No significant change in the spin relaxation probability of Rb atoms by single scattering from a tetracontane surface was observed by cooling the film from 305 to 123 K. The mean surface dwell time was estimated using a time-resolved method. Delay-time spectra, from which mean surface dwell times can be estimated, were measured at 305, 153, and 123 K, with a time window of $9.3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$ s. The increase in mean surface dwell time with cooling from 305 to 123 K was smaller than $4.4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$ s, which is significantly smaller than the value expected from the mean dwell time at room temperature measured using the Larmor frequency shift. These results can be explained by assuming a small number of scattering components, with a mean surface dwell time at least three orders of magnitude longer than the majority component.

arXiv:2108.04487•Physical Review A•Dec 6, 2021•9 citations

Experimental investigations of relaxation of spin polarized atoms on coated surfaces

Natarajan D. Bhaskar

The interaction of spin polarized cesium atoms on coated surfaces is examined. Coated surfaces find extensive applications in atomic devices-hydrogen masers and advanced rubidium frequency standards utilize wall coatings to obtain very narrow hyperfine resonances. A Cs atomic beam is hyperfine or spin polarized by optical pumping techniques using a single mode AlGaAs diode laser. The ground state distribution is probed before and after scattering from coated surfaces using laser induced fluorescence spectroscopy. The coatings under investigations are paraffin and organosilanes and these are known to be very weakly relaxing surfaces for polarized alkali atoms. The spin relaxation properties of paraffin and organosilane coatings have been studied in glass cell-vapor environment. In our experiments using polarized atomic beams, our goal is to examine in detail the hyperfine and spin relaxation properties of these coatings in a carefully controlled environment which is not possible in the gas cell environment. We measure the spin relaxation probability per wall collision as a function of temperature of the surface. Results of our studies will be presented.

Bulletin of the American Physical Society•May 1, 1993•0 citations

Rubidium dimers in paraffin-coated cells

Víctor M. Acosta, Andrey Jarmola, D Windes +7 more

Measurements were made to determine the density of rubidium dimer vapor in paraffin-coated cells. The number density of dimers and atoms in similar paraffin-coated and uncoated cells was measured by optical spectroscopy. Due to the relatively low melting point of paraffin, a limited temperature range of 43–80 °C was explored, with the lower end corresponding to a dimer density of less than 10 7 cm − 3 . With 1 min integration time, a sensitivity to dimer number density of better than 10 6 cm − 3 was achieved. No significant difference in dimer density between the cells was observed.

arXiv:1005.0215•New Journal of Physics•Aug 26, 2010•3 citations

Investigation of antirelaxation coatings for alkali-metal vapor cells using surface science techniques

Scott J. Seltzer, David J. Michalak, Marcus H. Donaldson +17 more

Many technologies based on cells containing alkali-metal atomic vapor benefit from the use of antirelaxation surface coatings in order to preserve atomic spin polarization. In particular, paraffin has been used for this purpose for several decades and has been demonstrated to allow an atom to experience up to 10 000 collisions with the walls of its container without depolarizing, but the details of its operation remain poorly understood. We apply modern surface and bulk techniques to the study of paraffin coatings in order to characterize the properties that enable the effective preservation of alkali spin polarization. These methods include Fourier transform infrared spectroscopy, differential scanning calorimetry, atomic force microscopy, near-edge x-ray absorption fine structure spectroscopy, and x-ray photoelectron spectroscopy. We also compare the light-induced atomic desorption yields of several different paraffin materials. Experimental results include the determination that crystallinity of the coating material is unnecessary, and the detection of C[Double Bond]C double bonds present within a particular class of effective paraffin coatings. Further study should lead to the development of more robust paraffin antirelaxation coatings, as well as the design and synthesis of new classes of coating materials.

arXiv:1002.4417•The Journal of Chemical Physics•Oct 11, 2010•63 citations

Light-induced desorption of alkali-metal atoms from paraffin coating

Evgeny B. Alexandrov, M. V. Balabas, Dmitry Budker +4 more

Observation of nonthermal, light-induced desorption of Cs and Rb atoms from paraffin coating is reported. Buffer-gas-free paraffin-coated cells containing Cs and Rb were exposed to laser light of various intensities and frequencies, and the change of the vapor densities as a function of time was investigated. Because atomic polarization relaxes very slowly in paraffin-coated cells (spin-relaxation times can be $\ensuremath{\gtrsim}1\mathrm{s}),$ they are applied in a variety of precision measurements (e.g., magnetometry, discrete symmetry tests, etc.). Light-induced desorption may be useful in such measurements as a method to control atomic density without changing the temperature of the cell.

Physical Review A•Oct 23, 2002•154 citations
Abstract With an objective to explore the surface interaction between alkali-metal atoms and an inert organic coating, we used an atomic beam to measure the velocity distribution of gaseous rubidium atoms scattered from a low-temperature tetracontane film. When the film temperature decreased from 300 K to 200 K, the number of scattered atoms did not change. At below 200 K, the number began to decrease until, finally, no scattered atoms were observable at 140 K. X-ray photoelectron spectroscopy at 160 K or below revealed rubidium atoms on the film surface. The temperature of the scattered atoms was the same as that of the film. Thermalization of scattered atoms at room temperature was reported previously, but this study is the first to report thermalization at low temperatures.
We performed scattering experiments using a rubidium (Rb) atomic beam on paraffin films and measured the angular and velocity distributions of scattered atoms. The paraffin films were prepared in various ways and characterized by atomic force microscopy and x-ray diffraction. The films exhibited various roughnesses and crystal structures. The paraffin films preserved the spin polarization of the scattered atoms. The measured angular distributions of all prepared films were consistent with Knudsen's cosine law. The velocity distributions were well fitted by Maxwell's distribution, characterized by a temperature much closer to the film temperature than to the atomic-beam temperature. We therefore concluded that the translational motion of the scattered atoms was thermalized with the paraffin films via single-scattering events.
The scattering of Rb atoms on an antirelaxation coating was studied. No significant change in the spin relaxation probability of Rb atoms by single scattering from a tetracontane surface was observed by cooling the film from 305 to 123 K. The mean surface dwell time was estimated using a time-resolved method. Delay-time spectra, from which mean surface dwell times can be estimated, were measured at 305, 153, and 123 K, with a time window of $9.3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$ s. The increase in mean surface dwell time with cooling from 305 to 123 K was smaller than $4.4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$ s, which is significantly smaller than the value expected from the mean dwell time at room temperature measured using the Larmor frequency shift. These results can be explained by assuming a small number of scattering components, with a mean surface dwell time at least three orders of magnitude longer than the majority component.
The interaction of spin polarized cesium atoms on coated surfaces is examined. Coated surfaces find extensive applications in atomic devices-hydrogen masers and advanced rubidium frequency standards utilize wall coatings to obtain very narrow hyperfine resonances. A Cs atomic beam is hyperfine or spin polarized by optical pumping techniques using a single mode AlGaAs diode laser. The ground state distribution is probed before and after scattering from coated surfaces using laser induced fluorescence spectroscopy. The coatings under investigations are paraffin and organosilanes and these are known to be very weakly relaxing surfaces for polarized alkali atoms. The spin relaxation properties of paraffin and organosilane coatings have been studied in glass cell-vapor environment. In our experiments using polarized atomic beams, our goal is to examine in detail the hyperfine and spin relaxation properties of these coatings in a carefully controlled environment which is not possible in the gas cell environment. We measure the spin relaxation probability per wall collision as a function of temperature of the surface. Results of our studies will be presented.
Measurements were made to determine the density of rubidium dimer vapor in paraffin-coated cells. The number density of dimers and atoms in similar paraffin-coated and uncoated cells was measured by optical spectroscopy. Due to the relatively low melting point of paraffin, a limited temperature range of 43–80 °C was explored, with the lower end corresponding to a dimer density of less than 10 7 cm − 3 . With 1 min integration time, a sensitivity to dimer number density of better than 10 6 cm − 3 was achieved. No significant difference in dimer density between the cells was observed.
Many technologies based on cells containing alkali-metal atomic vapor benefit from the use of antirelaxation surface coatings in order to preserve atomic spin polarization. In particular, paraffin has been used for this purpose for several decades and has been demonstrated to allow an atom to experience up to 10 000 collisions with the walls of its container without depolarizing, but the details of its operation remain poorly understood. We apply modern surface and bulk techniques to the study of paraffin coatings in order to characterize the properties that enable the effective preservation of alkali spin polarization. These methods include Fourier transform infrared spectroscopy, differential scanning calorimetry, atomic force microscopy, near-edge x-ray absorption fine structure spectroscopy, and x-ray photoelectron spectroscopy. We also compare the light-induced atomic desorption yields of several different paraffin materials. Experimental results include the determination that crystallinity of the coating material is unnecessary, and the detection of C[Double Bond]C double bonds present within a particular class of effective paraffin coatings. Further study should lead to the development of more robust paraffin antirelaxation coatings, as well as the design and synthesis of new classes of coating materials.
Observation of nonthermal, light-induced desorption of Cs and Rb atoms from paraffin coating is reported. Buffer-gas-free paraffin-coated cells containing Cs and Rb were exposed to laser light of various intensities and frequencies, and the change of the vapor densities as a function of time was investigated. Because atomic polarization relaxes very slowly in paraffin-coated cells (spin-relaxation times can be $\ensuremath{\gtrsim}1\mathrm{s}),$ they are applied in a variety of precision measurements (e.g., magnetometry, discrete symmetry tests, etc.). Light-induced desorption may be useful in such measurements as a method to control atomic density without changing the temperature of the cell.