Commissioning of the collinear laser spectroscopy system in the BECOLA facility at NSCL

Minamisono, K.; Mantica, P. F.; Klose, A.; Vinnikova, S.; Schneider, Anthony; Johnson, B. C.; Barquest, B. R.

doi:10.1016/j.nima.2013.01.038

Cited by 60 publications

(48 citation statements)

References 18 publications

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“…The 36 K or 37 K beams were separated from other fragmentation products in the A1900 fragment separator [13], thermalized in the NSCL gas stopper [14], 65 and extracted as singly-charged ions at an energy of 30 keV. The low-energy ion beams were transported to the BEam COoling and LAser spectroscopy (BECOLA) facility [15], where they were injected into a Radio Frequency Quadrupole (RFQ) cooler [16] filled with helium 70 buffer gas at ∼100 mTorr. The injected ion beams were thermalized through collisions with the buffer gas and extracted at an energy of 29856 ± 2 eV towards the collinear-laser spectroscopy (CLS) beam line.…”

Section: Experimental Methodsmentioning

confidence: 99%

Charge radii of neutron-deficientK36andK37

et al. 2015

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Background: The systematic trend in mean-square charge radii as a function of proton or neutron number exhibits a discontinuity at the nucleon-shell closures. While the established N = 28 shell closure is evident in the 10 charge radii of the isotopic chains of K through Mn, a similar signature of the N = 20 shell-closure is absent in the Ca region.Purpose: The isotope shift between neutron-deficient 36 K and 37 K was determined to investigate the change of the mean-square charge radii across N = 20 in the K isotopic chain.Methods: The D1 atomic hyperfine spectra of 36 K and 37 K were measured using an optical pumping and 15 subsequent β-decay asymmetry detection technique. Atomic rate equations were solved to fit the resonant line shape. The result was compared to Skyrme energy-density functional and shell-model calculations.Results: The isotope shift was obtained as δν 37,36 = −139(4)(3) MHz. Using a re-evaluated isotope shift, δν 39,37 = −264(2)(3) MHz, the isotope shift relative to 39 K was determined to be δν 39,36 = −403(5)(4) MHz. The differential mean-square charge radius was then deduced as δ r 2 39,36 = −0.16 (5)(8) Conclusions:The absence of the shell-closure signature at N = 20 in the K isotopic chain is understood as a balance between the monopole and the quadrupole proton-core polarizations below and above N = 20, respectively.

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Section: Experimental Methodsmentioning

confidence: 99%

Charge radii of neutron-deficientK36andK37

et al. 2015

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“…53 Fe beams were selected through the A1900 fragment separator [8], thermalized in a gas stopper [9], and extracted as singlycharged-ions at an energy of 30 keV. The Fe + beam was transported to the BEam COoler and LAser spectroscopy (BECOLA) facility [23,24], where the beam was injected into a Radio Frequency Quadrupole cooler/buncher [25]. The trapped ion beam was extracted at an energy of 29856(4) V as ion bunches for the bunched-beam collinear laser spectroscopy [26,27].…”

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confidence: 99%

Charge Radii of Neutron DeficientFe52,53Produced by Projectile Fragmentation

et al. 2016

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Bunched-beam collinear laser spectroscopy was performed on neutron-deficient 52,53 Fe prepared through in-flight separation followed by a gas stopping. This novel scheme is a major step to reach nuclides far from the stability line in laser spectroscopy. Differential mean-square charge radii δ r 2 of 52,53 Fe were determined relative to stable 56 Fe as δ r 2 56,52 = −0.034(13) fm 2 and δ r 2 56,53 = −0.218(13) fm 2 , respectively, from the isotope shift of atomic hyperfine structures. The multiconfiguration Dirac-Fock method was used to calculate atomic factors to deduce δ r 2 . The values of δ r 2 exhibit a minimum at the N = 28 neutron shell closure. Nuclear density functional theory with Fayans and Skyrme energy density functionals was used to interpret the data. The trend of δ r 2 along the Fe isotopic chain results from an interplay between single-particle shell structure, pairing, and polarization effects, and provides important data for understanding the intricate trend in the δ r 2 of closed-shell Ca isotopes. Introduction -Since the first estimate of a nuclear charge radius in 1909 [1,2], the size of a nucleus has been a central theme in nuclear structure [3][4][5][6][7]. Significant data on charge radii have been obtained at Isotope Separator On Line (ISOL) facilities, where isotopes of selective elements have been investigated. The ISOL production method, however, suffers from a serious limitation due to long release times from thick targets. This can lead to large decay losses for nuclides that have long diffusion/effusion times, and with short half-lives at the limits of the nuclear chart. In-flight production and separation [8] used in the present study can provide highenergy fast beams and enables studies on nuclides far from the stability line and elements that are difficult at ISOL facilities. Conversion of the fast beams into lowenergy beams in a gas [9] was already exploited, and was used for laser spectroscopy for the first time in the present study on transition-metal Fe known to be notoriously difficult to produce at ISOL facilities. This is a major step forward for laser spectroscopy experiments that complements such capabilities already well established at ISOL facilities.

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“…Typical stabilisation methods include the use of a suitable commercial wavelength meter [16] or by transferring the stability of a master laser via an FPI of low FSR [17]. Often, a frequency stabilised HeNe laser acts as the master laser achieving a long-term frequency stability of ∼400 kHz relative to the HeNe [18].…”

Section: Resultsmentioning

confidence: 99%

Development of a saturated absorption spectroscopy setup at IGISOL for characterisation of Fabry-Pérot interferometers

et al. 2016

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A saturated absorption spectroscopy setup was developed and optimised for the characterisation of a home-built and a commercial Fabry-Pérot interferometer (FPI). The free spectral range of these FPIs has been determined with reliable statistical and systematic errors. These FPIs will be used for accurate wavelength determination of broad-and narrowband pulsed Ti:Sapphire lasers used in resonance ionisation spectroscopy experiments.

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Commissioning of the collinear laser spectroscopy system in the BECOLA facility at NSCL

Cited by 60 publications

References 18 publications

Charge radii of neutron-deficientK36andK37

Charge radii of neutron-deficientK36andK37

Charge Radii of Neutron DeficientFe52,53Produced by Projectile Fragmentation

Development of a saturated absorption spectroscopy setup at IGISOL for characterisation of Fabry-Pérot interferometers

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