Soviet Journal of Quantum Electronics

Laser detection of rare radioactive isotopes. Selective enrichment of the initial state

Alexander A. Makarov

Published Jun 30, 1983• 2 citations

Abstract

An investigation is made of the enrichment of the initial state with atoms or ions of rare radioactive isotopes by using cw laser radiation. Estimates of the enrichment of metastable levels are obtained for 14C and 26Al atoms and 41Ca+ ions. The radioactive isotope 14C is used as an example to discuss the combination of enrichment of the initial state with multistage selective photoionization of atoms. It is shown that in this case, it is realistic to expect a selectivity higher than 1020.

DOI: 10.1070/qe1983v013n06abeh004277

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Soviet Journal of Quantum Electronics

Laser detection of rare radioactive isotopes. Selective enrichment of the initial state

Alexander A. Makarov

Published Jun 30, 1983• 2 citations

Publisher

Abstract

DOI: 10.1070/qe1983v013n06abeh004277

Related papers

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Оптика и спектроскопияJan 1, 20220 citations

We present studies of resonance-enhanced photoionization for isotope-selective loading of

{\mathrm{Ca}}^{+}

into a Paul trap. The ${4s}^{2}{}^{1}{S}_{0}\ensuremath{\leftrightarrow}4s4p{}^{1}{P}_{1}$ transition of neutral calcium is driven by a 423 nm laser and the atoms are photoionized by a second laser at 389 nm. Isotope selectivity is achieved by using crossed atomic and laser beams to reduce the Doppler width significantly below the isotope shifts in the 423 nm transition. The loading rate of ions into the trap is studied under a range of experimental parameters for the abundant isotope

{}^{40}{\mathrm{Ca}}^{+}.

Using the fluorescence of the atomic beam at 423 nm as a measure of the Ca number density, we estimate a lower limit for the absolute photoionization cross section of 170(60) Mb. We achieve loading and laser cooling of all the naturally occurring isotopes, without the need for enriched sources. Laser heating/cooling is observed to enhance the isotope selectivity. In the case of the rare species

{}^{43}{\mathrm{Ca}}^{+}

and

{}^{46}{\mathrm{Ca}}^{+},

which have not previously been laser cooled, the loading is not fully isotope selective, but we show that pure crystals of

{}^{43}{\mathrm{Ca}}^{+}

may nevertheless be obtained. We find that for loading

{}^{40}{\mathrm{Ca}}^{+}

the 389 nm laser may be replaced by an incoherent source.

We demonstrate an experimental technique that selects the nuclear spin I=0 isotope

^{138}\mathrm{Ba}

for spectroscopic measurements from a beam of natural barium containing seven stable isotopes. A cw dye laser is used to optically pump the I=3/2 isotopes

^{135}\mathrm{Ba}

and

^{137}\mathrm{Ba}

into the metastable 6s5d

^{1}

{\mathit{D}}_{2}

and

^{3}

{\mathit{D}}_{1,2}

levels via the 6s6p

^{1}

{\mathit{P}}_{1}

excited state, leaving nearly pure

^{138}\mathrm{Ba}

in the ground state. Photoionization spectra of the excited 5d6p

^{3}

{\mathit{D}}_{1}

even isotope state recorded with optical pumping of

^{135}\mathrm{Ba}

and

^{137}\mathrm{Ba}

to the metastable levels are essentially devoid of forbidden features associated with the hyperfine interaction in the odd isotopes.