Selective resonant ionization of zirconium isotopes using intermediate-state alignment

Green, L. W.; McRae, Glenn; Rochefort, Paul A.

doi:10.1103/physreva.47.4946

Cited by 26 publications

(17 citation statements)

References 10 publications

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“…This population alignment produced by the first laser is probed by a second laser for which, the electric field makes an angle θ with respect to the polarization axis of the first laser. Theoretical considerations show that the square matrix element for the secondstep transition J 2 → J 3 is proportional to Due to this redistribution of atoms between the magnetic sublevels on changing the quantization axis [13][14][15][16], the second-step transition, which is forbidden for ê 1 �ê 2 polarization in case of an even isotope, becomes allowed for different orientations of ê 2 with respect to ê 1 , thus degrading the selectivity of the process.…”

Section: Resultsmentioning

confidence: 99%

Polarization-based isotope-selective two-color photoionization of atomic samarium using broadband lasers

et al. 2015

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spectra are overlapping. An alternative isotope separation method based on polarization selection rules using broadband lasers has been previously applied for separation of odd and even isotopes of Zr, Gd, and Yb where the isotope shifts are small and the hyperfine spectra are complex [1][2][3][4][5][6][7][8]. Isotope separation of many of these elements is of great importance to nuclear industry [1][2][3][4][5][6]. In this method, odd isotopes with nonzero nuclear spin are selectively excited, while even isotopes with zero nuclear spin are prohibited from excitation by judiciously choosing a proper excitation sequence of angular momenta of the levels and the laser polarizations. However, this method is applicable to elements having states with low total angular momentum (J values).Atomic samarium (Sm I) has seven naturally abundant isotopes 144 Sm (3.1 %), 147 Sm (15 %), 148 Sm (11.3 %), 149 Sm (13.8 %), 150 Sm (7.4 %), 152 Sm (26.6 %), and 154 Sm (22.6 %). Among these, 149 Sm, with high thermal neutron absorption cross section (40,140 barns), is a promising candidate as burnable poison in nuclear reactors [9]. The use of natural samarium as a burnable poison was discarded previously because of the large residual negative reactivity worth of samarium isotopes and their daughter products at the end of life of the fuel. Recently, Renier et al. [10] have investigated the potential benefits of using enriched samaria (Sm 2 O 3 ) as a burnable poison in the fuel pellets of PWRs and shown that the use of Sm enriched in 149 Sm has greatly reduced this residual absorber problem.In this paper, we report isotope-selective photoionization of atomic samarium (Sm I) using two-color resonance ionization polarization spectroscopy with broadband lasers. We have identified a two-color excitation scheme 0 cm −1 (J = 0) → 15650.5 cm −1 (J = 1) → 33116.8 cm −1 (J = 1) → Sm + for selective excitation of the odd isotopes of Sm I [11,12]. Using this scheme, selective excitation of Abstract An isotope separation method based on polarization selection rules is applied to atomic samarium by using two-color resonance ionization spectroscopy with broadband lasers. In this method, odd isotopes with nonzero nuclear spin are selectively excited, while even isotopes with zero nuclear spin are prohibited from excitation using two parallel linearly polarized lasers. We have identified a two-color excitation scheme 0 cm −1 (J = 0) → 15650.5 cm −1 (J = 1) → 33116.8 cm −1 (J = 1) → Sm + for selective excitation of the odd isotopes of Sm I. Using this scheme, selective excitation of odd isotopes of Sm I ( 147 Sm and 149 Sm) with an isotopic selectivity better than 40 has been demonstrated. In addition, the effect of different polarization states of the excitation lasers and relative polarization angle between them on the selectivity of odd isotopes has also been studied. The dependence of the even mass isotope signal on the relative polarization angle followed sin 2 θ, which is in excellent agreement with theoretical predictions.

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Section: Resultsmentioning

confidence: 99%

Polarization-based isotope-selective two-color photoionization of atomic samarium using broadband lasers

et al. 2015

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“…Historically, some of the potentially attractive options for enriching Zr in Zr-90 are through the use of atomic vapor laser isotope separation with ionized zirconium vapour [15], the use of a plasma centrifuge [16], or through the use of solvent extraction methods combined with photon reactions [17].…”

Section: Future Studiesmentioning

confidence: 99%

Performance Improvements for Thorium-Based Fuels in Pressure-Tube Heavy-Water Reactors

Bromley¹,

Colton

Collins

2017

CNL Nuclear Review

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“…Selective resonant ionization of 91 Zr from other Zr isotopes has also been investigated as a function of angle between the polarization axes of consecutive laser pulses [3]. The selectivity scheme for orthogonal polarization can be rationalized by considering that one of the linearly polarized beams can be decomposed into the superposition of right and left circularly polarized (RCP + LCP) beams with quantization axis parallel to the polarization direction of the first beam.…”

Section: Principle Of Pd Isotope Selective Photoionizationmentioning

confidence: 99%

“…Considerable research has investigated the separation of these valuable metals from other nuclides [2][3][4] including recovery from tailings from previous decades of fission waste. However, these platinum group metals contained in isotopes from even-mass-number isotopes (within observation error), which is equally efficient as the selectivity obtained in this work using circularly polarized light.…”

Section: Introductionmentioning

confidence: 99%

Application of an orthogonally polarized laser scheme for selective photoionization of palladium isotopes

et al. 2016

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radioactive waste are presently unable to be utilized due to the co-presence of long-lived radioactive isotopes. To date, techniques to selectively remove radioactive isotopes have not been established on a commercial scale.Palladium is one of the platinum group metals and is of high value in industry, and as ore deposits are rare, motivation for recycling is high. Palladium is present in the yield from fission processes, containing the isotopes Pd is not naturally occurring and has a half-life of 6.5 million years, meaning simply storing for an extended period is not feasible (in contrast to rhodium, for example, which essentially becomes inactive after 50 years). There are three methodologies to recycle Pd with laser photoionization; firstly, resonance ionization mass spectrometry (RIMS) [5,6]. Secondly, using very narrow line-width lasers precisely tuned to the transition for the isotope; this technique, however, is not considered viable as the isotope shifts for Pd [7] are much smaller than the Doppler-broadened absorption linewidths. Thirdly, a general technique proposed by Balling and Wright [8] using circularly polarized lasers for isotope selectivity, in which only odd-mass-number isotopes having nonzero nuclear spin (and thus having hyperfine structure) are able to be ionized due to selection rules. The feasibility and practicality of this third technique when applied to platinum group metals is reported by Chen [9], and may yield higher selectivity ratios than RIMS [10], although further development is required to fully assess any relative merits.Presented here, as an extension to the third technique using circularly polarized lasers, is a means using two counter-propagating, orthogonally orientated, linearly polarized laser beams. This is a considerably simpler method, and we demonstrate complete selectivity of odd-mass-number Abstract We present a technique using two orthogonal linearly polarized lasers to improve practical implementation of the separation of odd-and even-mass-number palladium isotopes. Dye lasers are used for a three-step photoionization of vaporized palladium, where due to the transition selection rules only odd-mass-number isotopes are ionized and removed from the palladium beam via an electric field. Schemes presented in the literature use two counter-propagating circularly polarized beams, which are in practice difficult to implement perfectly. In contrast, two counterpropagating orthogonally polarized beams are technically less demanding to implement, yet the scheme retains the same high selectivity demonstrated in this work of >1200 (or 99.7 ± 0.3 %).

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Selective resonant ionization of zirconium isotopes using intermediate-state alignment

Cited by 26 publications

References 10 publications

Polarization-based isotope-selective two-color photoionization of atomic samarium using broadband lasers

Polarization-based isotope-selective two-color photoionization of atomic samarium using broadband lasers

Performance Improvements for Thorium-Based Fuels in Pressure-Tube Heavy-Water Reactors

Application of an orthogonally polarized laser scheme for selective photoionization of palladium isotopes

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