arXiv:0708.3826 · Physical Review A

Trapping radioactive Rb82 in an optical dipole trap and evidence of spontaneous spin polarization

D. Feldbaum, H. Wang, Jonathan D. Weinstein, D. Vieira, Xinxin Zhao

Published Nov 20, 2007• 12 citations

Abstract

Optical trapping of selected species of radioactive atoms has great potential in precision measurements for testing fundamental physics such as the electric dipole moment, atomic parity nonconservation, and parity-violating $\ensuremath{\beta}$-decay correlation coefficients. We report on the trapping of ${10}^{4}$ radioactive $^{82}\mathrm{Rb}$ atoms $({t}_{1∕2}=75\phantom{\rule{0.3em}{0ex}}\mathrm{s})$ with a trap lifetime of $\ensuremath{\sim}55\phantom{\rule{0.3em}{0ex}}\mathrm{s}$ in an optical dipole trap. Transfer efficiency from the magneto-optical trap is $\ensuremath{\sim}14%$. We further report evidence of spontaneous spin polarization of the atoms in optical dipole trap loading. These advancements are an important step toward a new generation of precision nuclear-spin--$\ensuremath{\beta}$-emission direction correlation measurements with polarized $^{82}\mathrm{Rb}$ atoms.

DOI: 10.1103/physreva.76.051402

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Magneto-optical trapping of radioactive 82Rb atoms

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arXiv:0708.3826 · Physical Review A

Trapping radioactive Rb82 in an optical dipole trap and evidence of spontaneous spin polarization

D. Feldbaum, H. Wang, Jonathan D. Weinstein, D. Vieira, Xinxin Zhao

Published Nov 20, 2007• 12 citations

arXiv HTML PDF

Abstract

\ensuremath{\beta}

-decay correlation coefficients. We report on the trapping of

{10}^{4}

radioactive

^{82}\mathrm{Rb}

atoms

({t}_{1∕2}=75\phantom{\rule{0.3em}{0ex}}\mathrm{s})

with a trap lifetime of

\ensuremath{\sim}55\phantom{\rule{0.3em}{0ex}}\mathrm{s}

in an optical dipole trap. Transfer efficiency from the magneto-optical trap is

\ensuremath{\sim}14%

. We further report evidence of spontaneous spin polarization of the atoms in optical dipole trap loading. These advancements are an important step toward a new generation of precision nuclear-spin--

\ensuremath{\beta}

-emission direction correlation measurements with polarized

^{82}\mathrm{Rb}

atoms.

DOI: 10.1103/physreva.76.051402

Related papers

Magneto-optical trapping of radioactive 82Rb atoms

Ralf Guckert, Xinxin Zhao, S. G. Crane +5 more

We report the successful trapping of $6\ifmmode\times\else\texttimes\fi{}{10}^{6}$ ${}^{82}\mathrm{Rb}$ ${(t}_{1/2}=75\mathrm{s})$ atoms with a trap lifetime of $\ensuremath{\sim}30\mathrm{s}$ in a magneto-optical trap that is coupled to an off-line mass separator. Efficient sample introduction is achieved by implanting ${}^{82}\mathrm{Rb}$ ions into a small yttrium catcher foil located inside the trapping cell. Upon heating, the radioactive atoms are released from the foil and trapped without significant gas loading. This advancement makes a variety of high-precision electroweak interaction experiments possible, including the measurement of \ensuremath{\beta}-decay correlations associated with spin-polarized ${}^{82}\mathrm{Rb}$ nuclei.We report the successful trapping of $6\ifmmode\times\else\texttimes\fi{}{10}^{6}$ ${}^{82}\mathrm{Rb}$ ${(t}_{1/2}=75\mathrm{s})$ atoms with a trap lifetime of $\ensuremath{\sim}30\mathrm{s}$ in a magneto-optical trap that is coupled to an off-line mass separator. Efficient sample introduction is achieved by implanting ${}^{82}\mathrm{Rb}$ ions into a small yttrium catcher foil located inside the trapping cell. Upon heating, the radioactive atoms are released from the foil and trapped without significant gas loading. This advancement makes a variety of high-precision electroweak interaction experiments possible, including the measurement of \ensuremath{\beta}-decay correlations associated with spin-polarized ${}^{82}\mathrm{Rb}$ nuclei.

Physical Review ASep 1, 199830 citations

Polarized atoms in a far-off-resonance yttrium-aluminum-garnet-laser optical dipole trap

Fengzhou Fang, H. Wang, D. Feldbaum +2 more

Optical trapping of radioactive atoms has a great potential in precision measurements for testing fundamental physics such as electric-dipole moment, atomic parity nonconservation, and parity-violating $\ensuremath{\beta}$-decay correlation coefficients. One challenge that remains is to polarize the atoms to a high degree, and to measure the polarization of the sample and its evolution over time. In this paper we report on the polarization study of Rb atoms in a yttrium-aluminum-garnet (YAG)-laser optical dipole trap using both Faraday rotation polarimetry and resolved Zeeman spectroscopy techniques. We have prepared a cold cloud of polarized atoms and observed that its spin relaxation due to light scattering is suppressed in the YAG dipole trap. The spin polarization is further purified and maintained when the two-body collision loss rate between atoms in mixed spin states is greater than the one-body trap loss. These advancements are an important step toward a new generation of precision measurement with polarized trapped atoms.Optical trapping of radioactive atoms has a great potential in precision measurements for testing fundamental physics such as electric-dipole moment, atomic parity nonconservation, and parity-violating $\ensuremath{\beta}$-decay correlation coefficients. One challenge that remains is to polarize the atoms to a high degree, and to measure the polarization of the sample and its evolution over time. In this paper we report on the polarization study of Rb atoms in a yttrium-aluminum-garnet (YAG)-laser optical dipole trap using both Faraday rotation polarimetry and resolved Zeeman spectroscopy techniques. We have prepared a cold cloud of polarized atoms and observed that its spin relaxation due to light scattering is suppressed in the YAG dipole trap. The spin polarization is further purified and maintained when the two-body collision loss rate between atoms in mixed spin states is greater than the one-body trap loss. These advancements are an important step toward a new generation of precision measurement with polarized trapped atoms.

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G. Gwinner, J. A. Behr, Sydney B. Cahn +4 more

Radioactive $^{79}\mathrm{Rb}$ atoms have been produced in a nuclear reaction and were captured into a magneto-optic trap in a cell. A fluorescence signal was obtained from 80 $^{79}\mathrm{Rb}$ atoms in the trap. The efficiency of the process is estimated as 1\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}5}$ atom in the trap for every atom/sec produced. This efficiency is sufficient to develop further experiments to measure atomic properties of Fr with the eventual goal of observing parity nonconservation effects in neutral atoms of different radioactive isotopes of Fr.Radioactive $^{79}\mathrm{Rb}$ atoms have been produced in a nuclear reaction and were captured into a magneto-optic trap in a cell. A fluorescence signal was obtained from 80 $^{79}\mathrm{Rb}$ atoms in the trap. The efficiency of the process is estimated as 1\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}5}$ atom in the trap for every atom/sec produced. This efficiency is sufficient to develop further experiments to measure atomic properties of Fr with the eventual goal of observing parity nonconservation effects in neutral atoms of different radioactive isotopes of Fr.

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\ensuremath{\beta}

-decay correlation coefficients. We report on the trapping of

{10}^{4}

radioactive

^{82}\mathrm{Rb}

atoms

({t}_{1∕2}=75\phantom{\rule{0.3em}{0ex}}\mathrm{s})

with a trap lifetime of

\ensuremath{\sim}55\phantom{\rule{0.3em}{0ex}}\mathrm{s}

in an optical dipole trap. Transfer efficiency from the magneto-optical trap is

\ensuremath{\sim}14%

. We further report evidence of spontaneous spin polarization of the atoms in optical dipole trap loading. These advancements are an important step toward a new generation of precision nuclear-spin--

\ensuremath{\beta}

-emission direction correlation measurements with polarized

^{82}\mathrm{Rb}

atoms.

We report the successful trapping of $6\ifmmode\times\else\texttimes\fi{}{10}^{6}$

{}^{82}\mathrm{Rb}

{(t}_{1/2}=75\mathrm{s})

atoms with a trap lifetime of $\ensuremath{\sim}30\mathrm{s}$ in a magneto-optical trap that is coupled to an off-line mass separator. Efficient sample introduction is achieved by implanting

{}^{82}\mathrm{Rb}

ions into a small yttrium catcher foil located inside the trapping cell. Upon heating, the radioactive atoms are released from the foil and trapped without significant gas loading. This advancement makes a variety of high-precision electroweak interaction experiments possible, including the measurement of \ensuremath{\beta}-decay correlations associated with spin-polarized

{}^{82}\mathrm{Rb}

nuclei.

%

. The initial atom distribution in different Zeeman levels is measured by using a combination of microwave excitation, laser pushing, and atomic retrap techniques. The nuclear-spin polarization is further purified to 99.2(2)

%

in 10 s and maintained above 99

%

because the two-body collision loss rate between atoms in mixed spin states is greater than the one-body trap loss rate. Systematic effects on the nuclear polarization, including the off-resonance Raman scattering, magnetic field gradient, and background gas collisions, are discussed.

Radioactive

^{79}\mathrm{Rb}

atoms have been produced in a nuclear reaction and were captured into a magneto-optic trap in a cell. A fluorescence signal was obtained from 80

^{79}\mathrm{Rb}

atoms in the trap. The efficiency of the process is estimated as 1\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}5}$ atom in the trap for every atom/sec produced. This efficiency is sufficient to develop further experiments to measure atomic properties of Fr with the eventual goal of observing parity nonconservation effects in neutral atoms of different radioactive isotopes of Fr.

First Measurement of the Atomic Electric Dipole Moment of

^{225}

The radioactive radium-225 (

^{225}

Ra) atom is a favorable case to search for a permanent electric dipole moment (EDM). Due to its strong nuclear octupole deformation and large atomic mass,

^{225}

Ra is particularly sensitive to interactions in the nuclear medium that violate both time-reversal symmetry and parity. We have developed a cold-atom technique to study the spin precession of

^{225}

Ra atoms held in an optical dipole trap, and demonstrated the principle of this method by completing the first measurement of its atomic EDM, reaching an upper limit of

|

d

(

^{225}

Ra)

|