Anomalous linewidths and peak-height ratios in137Ba hyperfine lines

Cannon, Bret D.; Whitaker, T. J.; Gerke, G.K.; Bushaw, Bruce A.

doi:10.1007/bf00684089

Cited by 7 publications

(4 citation statements)

References 11 publications

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“…While the fit result for the Gaussian component of 23.6(6) MHz (FWHM) is consistent with a value of 27 MHz expected for a source temperature of 800 K and 5 • atomic beam divergence, the 11.7(8) MHz (FWHM) Lorentzian component is almost twice as large as expected from the ∼ 30.3 ns natural lifetime of the excited state (weighted average of experimental lifetime values cited in [22]). This is ascribed to onset of saturation caused by cylindrical focussing of the laser beam and anomalous lineshapes due to optical pumping, as has been observed previously for Ba [17]. The experimentally observed peak-height ratios of 0.136(4) : 0.292(6) : 1 compared to the expectation of 0.159 : 0.478 : 1 obtained from standard intensity rules [23] also indicate some degree of optical pumping.…”

Section: Spectroscopic Investigationssupporting

confidence: 64%

“…For isotopes with a nuclear spin (mostly odd-mass isotopes), hyperfine structure splitting presents additional difficulties: the transition oscillator strength is partitioned among several hyperfine components, which reduces excitation efficiency when the high-resolution laser is tuned to a single component. Furthermore, redistribution of magnetic substate populations, resulting from optical pumping, can cause the effective transition strength to be a variable function of laser intensity, tuning, and exposure time [17]. This can introduce additional uncertainties in ratio measurements for isotope pairs with differing nuclear spin; however, this is not a problem for 133,135,137 Cs since all have the same nuclear spin of I = 7/2.…”

Section: Introductionmentioning

confidence: 98%

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Evaluation of resonance ionization mass spectrometry for the determination of ¹³⁵Cs/¹³⁷Cs isotope ratios in low-level samples

Pibida¹,

Nörtershäuser²,

Hutchinson³

et al. 2001

Radiochimica Acta

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Resonance ionization / Trace analysis / 135 Cs/ 137 Cs isotope ratios / Mass spectrometry Summary. The ability of Resonance Ionization Mass Spectrometry (RIMS) to reliably determine the ratio of 135 Cs/ 137 Cs in the presence of large backgrounds has been evaluated. Singleresonance excitation of Cs 6s 2 S 1/2 (F = 4) → 6 p 2 P 3/2 (F = 5) with an extended cavity diode laser was followed by photoionization with the 488 nm line of an argon ion laser. While the principal objective was to avoid isobaric interferences, an optical selectivity of 3 orders of magnitude against stable 133 Cs was attained for both 135 Cs and 137 Cs. The overall RIMS efficiency was found to be ∼ 2 × 10 −6 with a combined (laser and mass spectrometer) selectivity of ∼ 10 10 for both 135 Cs and 137 Cs against 133 Cs. The performance with respect to efficiency, selectivity, and isobar suppression has been compared to conventional thermal ionization mass spectrometry (TIMS). Measurements to determine the chronological age of a burn-up sample have been performed using both methods.

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Section: Spectroscopic Investigationssupporting

confidence: 64%

Section: Introductionmentioning

confidence: 98%

Evaluation of resonance ionization mass spectrometry for the determination of ¹³⁵Cs/¹³⁷Cs isotope ratios in low-level samples

Pibida¹,

Nörtershäuser²,

Hutchinson³

et al. 2001

Radiochimica Acta

View full text Add to dashboard Cite

show abstract

“…Most authors fit the observed structure by fixing the HFS interval and intensity ratios according to Clebsch-Gordan coefficients. However, optical pumping effects can vary the component line intensities dramatically, even at excitation intensities well below saturation [92,93]. Further, linear polarization and magnetic shielding [91] do not prevent optical pumping; rather one should use vanishingly small excitation intensity and/or (pseudo) random polarization.…”

Section: Extraction Of δ R 2 C For 67 Limentioning

confidence: 99%

Isotope-shift measurements of stable and short-lived lithium isotopes for nuclear-charge-radii determination

et al. 2011

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Changes in the mean square nuclear charge radii along the lithium isotopic chain were determined using a combination of precise isotope shift measurements and theoretical atomic structure calculations. Nuclear charge radii of light elements are of high interest due to the appearance of the nuclear halo phenomenon in this region of the nuclear chart. During the past years we have developed a laser spectroscopic approach to determine the charge radii of lithium isotopes which combines high sensitivity, speed, and accuracy to measure the extremely small field shift of an 8-ms-lifetime isotope with production rates on the order of only 10 000 atoms/s. The method was applied to all bound isotopes of lithium including the two-neutron halo isotope 11 Li at the on-line isotope separators at GSI, Darmstadt, Germany, and at TRIUMF, Vancouver, Canada. We describe the laser spectroscopic method in detail, present updated and improved values from theory and experiment, and discuss the results.

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“…The performance of the PNNL system has been reported previously 7 , while this work concentrates on results with the NIST system and comparison with the PNNL measurements. Optical pumping can redistribute magnetic sub-state populations and cause the effective transition strength to be a variable function of laser intensity, tuning, and exposure time 20 . Resonance ionization spectroscopy 8 (RIS) avoids isobaric interferences by selectively ionizing the element of interest by using tunable lasers.…”

Section: Introductionmentioning

confidence: 99%

Comparison of resonance ionization mass spectrometry systems for the determination of¹³⁵Cs/¹³⁷Cs isotope ratios

et al. 2002

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The performance of the Resonance Ionization Mass Spectrometry (RIMS) system at the National Institute of Standards and Technology (NIST) has been compared to a similar system at Pacific Northwest National Laboratory (PNNL). Efficiency and selectivity measurements were performed with both systems and compared to conventional thermal ionization mass spectrometry (TIMS). Determination of the 135 Cs / 137 Cs ratio was performed using single-resonance excitation 6s 2 S 1/2 (F = 4) ® 6p 2 P 3/2 (F¢ = 5) with an external cavity diode laser followed by photoionization with the 488 nm line of an argon ion laser. Optical selectivity of more than 2 orders of magnitude against stable 133 Cs was attained for 135 Cs and 137 Cs for both systems with an overall selectivity of 10 9 for the PNNL system and 10 8 for the NIST system. Overall efficiencies of 2´10 -6 and 5´10 -7 were measured for the PNNL and NIST systems respectively. Measurements to determine the chronological age of a nuclear burn-up sample have been performed using both RIMS systems as well as TIMS.

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Anomalous linewidths and peak-height ratios in137Ba hyperfine lines

Cited by 7 publications

References 11 publications

Evaluation of resonance ionization mass spectrometry for the determination of ¹³⁵Cs/¹³⁷Cs isotope ratios in low-level samples

Evaluation of resonance ionization mass spectrometry for the determination of ¹³⁵Cs/¹³⁷Cs isotope ratios in low-level samples

Isotope-shift measurements of stable and short-lived lithium isotopes for nuclear-charge-radii determination

Comparison of resonance ionization mass spectrometry systems for the determination of¹³⁵Cs/¹³⁷Cs isotope ratios

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Anomalous linewidths and peak-height ratios in137Ba hyperfine lines

Cited by 7 publications

References 11 publications

Evaluation of resonance ionization mass spectrometry for the determination of 135Cs/137Cs isotope ratios in low-level samples

Evaluation of resonance ionization mass spectrometry for the determination of 135Cs/137Cs isotope ratios in low-level samples

Isotope-shift measurements of stable and short-lived lithium isotopes for nuclear-charge-radii determination

Comparison of resonance ionization mass spectrometry systems for the determination of135Cs/137Cs isotope ratios

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Evaluation of resonance ionization mass spectrometry for the determination of ¹³⁵Cs/¹³⁷Cs isotope ratios in low-level samples

Evaluation of resonance ionization mass spectrometry for the determination of ¹³⁵Cs/¹³⁷Cs isotope ratios in low-level samples

Comparison of resonance ionization mass spectrometry systems for the determination of¹³⁵Cs/¹³⁷Cs isotope ratios