In-source spectroscopy on astatine and radium for resonant laser ionization

Raeder, S.; Lassen, J.; Heggen, H.; Teigelhöfer, A.

doi:10.1007/s10751-014-1040-9

Cited by 10 publications

(28 citation statements)

References 15 publications

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“…Unfortunately, for these levels, no clear identification was given. More recently, at the Isotope Separator and Accelerator (ISAC) facility at TRIUMF, laser spectroscopy was performed to search for additional high lying bound states as well as for autoionizing resonances in astatine [13] . While no auto-ionizing resonances were measured in the investigated region, this experiment led however to the observation of four new odd-parity levels at 69,615.1, 70,055.4, 71,376.7 and 71,708.7 cm −1 , but, in this case also, no spectroscopic designation was reported.…”

Section: Available Experimental Datamentioning

confidence: 99%

“…The first goal of our work was to clearly identify the energy levels observed between 0 and 58,805 cm −1 in previous experiments involving atomic astatine [12][13] . The computational procedure that we have used for modelling the atomic structure and calculating radiative transition parameters in At I is the pseudo-relativistic Hartree-Fock (HFR) method described in detail by Cowan [20] .…”

Section: Low-lying Energy Levels In the 6p 5 6p 4 7s And 6p 4 7p Comentioning

confidence: 99%

“…As regards its electronic structure, the ground state of the astatine atom is 6p 5 2 P 3/2 while the lowest excited configurations are of the type 6p 4 nl (with nl = 7s, 7p, 6d, 5f, …). Nevertheless, only two excited levels (6p 4 7s 4 P 3/2,5/2 ) were clearly classified until now [11] , although some additional tentative identifications of higher-lying states were suggested from recent experiments [12,13] . As support to further experimental investigations of astatine, it is however useful to know the atomic structure of this element in the most complete possible way.…”

Section: Introductionmentioning

confidence: 98%

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Newly identified energy levels and calculated transition rates in astatine atom, the rarest element on Earth

Quinet

Sicorello

2018

Journal of Quantitative Spectroscopy and Radiative Transfer

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A theoretical investigation of the atomic structure and radiative parameters involving the lowest states within the 6p 5 , 6p 4 7s and 6p 4 7p configurations of neutral astatine is reported for the first time in the present paper. Using different physical models based on the pseudo-relativistic Hartree-Fock approach, the influence of intravalence, core-valence and core-core electron correlation on the atomic parameters is discussed in detail. This work allowed us to establish the intermediate-coupling composition and to clearly fix the spectroscopic designation of six excited levels within the 6p 4 7s and 6p 4 7p configurations which had been located in previous experimental studies. In addition new tentative identifications of four levels belonging to the 6p 4 9p and 6p 4 10p configurations are reported in this work together with predicted level energies along the 6p 4 n p and 6p 4 n d Rydberg series up to n = 50.

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Section: Available Experimental Datamentioning

confidence: 99%

Section: Low-lying Energy Levels In the 6p 5 6p 4 7s And 6p 4 7p Comentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

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Newly identified energy levels and calculated transition rates in astatine atom, the rarest element on Earth

Quinet

Sicorello

2018

Journal of Quantitative Spectroscopy and Radiative Transfer

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“…The particularly simple resonant photoionization scheme we use in barium does not have an exact analogue in radium, since the corresponding level 6d7p 3 D 1 lies at significantly higher energy. Recently, photoionization of radium has successfully been implemented at the triumf and isolde accelerator facilities [124,125] to increase the yield of radioactive ions over surface ionization (using schemes with more than two excitation steps). In any case, the radioactivity of radium prevents us from simply filling an oven as with barium and we took the first steps to build a radium ion source using a different approach, detailed in the next section.…”

Section: Photoionizationmentioning

confidence: 99%

“…One method is to use a particle accelerator. This technique is used at the triumf [124] and isolde facilities [125] and has previously been used in our group to study the neutron-poor isotopes [209][210][211][212][213][214] Ra [45,49,64]. However, for further experiments an offline source was desired for greater flexibility and simplicity.…”

Section: Offline Ra + Source Designmentioning

confidence: 99%

Spectroscopy of Trapped ¹³⁸Ba⁺ Ions for Atomic Parity Violation and Optical Clocks

Dijck

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Trapped Ba + and Ra + ions offer the possibility to test the Standard Model by performing an independent high-precision determination of the Weinberg angle (sin 2 θ W) at low momentum transfer. In such a measurement of atomic parity violation, table-top experiments complement studies of weak interaction effects at high energy in the search for new physics. The singly-charged heavy alkaline earth metal ions combine high intrinsic sensitivity with tractable atomic structure owing to their single valence electron. In addition, trapped Ba + or Ra + ions can serve as reference for an optical atomic clock that is sensitive to variation of the fine structure constant α. Determining sin 2 θ W requires localizing a single laser-cooled Ba + or Ra + ion in a standing-wave light field to a fraction of an optical wavelength. High-precision atomic theory calculations are crucial for interpreting the measurements and need experimental input. We have performed preparatory spectroscopy measurements with trapped Ba + ions and investigated experimental techniques for characterizing ion traps. We have determined the optical transition frequencies between low-lying levels of 138 Ba + with laser spectroscopy referenced to an optical frequency comb. Using a lineshape model based on eight-level optical Bloch equations, we determined the 6s 2 S 1/2-5d 2 D 3/2 transition frequency to be 146 114 384.0(0.1) MHz and the 5d 2 D 3/2-6p 2 P 1/2 transition frequency to be 461 311 878.5(0.1) MHz, obtaining for the first time sub-MHz precision on these transitions. Light shifts play an important role in the measurement of sin 2 θ W and offer a way to obtain information on (ratios of) atomic transition matrix elements. We have carried out an exploratory study of the light shift in 138 Ba + caused by an off-resonant laser tuned close to the 5d 2 D 3/2-6p 2 P 1/2 transition. The observed spectra are analyzed by combining the optical lineshapes with calculated light shifts of individual Zeeman components. Atomic state lifetimes provide a benchmark for calculations of transition amplitudes. We have measured the lifetime of the long-lived 5d 2 D 5/2 level in 138 Ba + using a technique based on quantum jumps with one to four trapped ions. We have investigated known systematic effects in detail to evaluate their influence. We measured the lifetime of the 5d 2 D 5/2 level to be 26.3(0.6) s, which is about 4σ shorter than previously published experimental results. This discrepancy needs to be clarified to ensure the reliability of atomic parity violation measurements ahead. This work contributes toward a precise determination of sin 2 θ W with trapped Ba + or Ra + ions in search of physics beyond the Standard Model.

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Ionization Scheme Development for the ISOLDE RILIS

Goodacre

2021

Applied Laser Spectroscopy for Nuclear Physics

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In-source spectroscopy on astatine and radium for resonant laser ionization

Cited by 10 publications

References 15 publications

Newly identified energy levels and calculated transition rates in astatine atom, the rarest element on Earth

Newly identified energy levels and calculated transition rates in astatine atom, the rarest element on Earth

Spectroscopy of Trapped ¹³⁸Ba⁺ Ions for Atomic Parity Violation and Optical Clocks

Ionization Scheme Development for the ISOLDE RILIS

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