124 research outputs found

    On-line Excited-State Laser Spectroscopy of Trapped Short-Lived Ra+^+ Ions

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    As an important step towards an atomic parity violation experiment in one single trapped Ra+^+ ion, laser spectroscopy experiments were performed with on-line produced short-lived 212,213,214^{212,213,214}Ra+^+ ions. The isotope shift of the 6\,^2D3/2_{3/2}\,-\,7\,^2P1/2_{1/2} and 6\,^2D3/2_{3/2}\,-\,7\,^2P3/2_{3/2} transitions and the hyperfine structure constant of the 7\,^2S1/2_{1/2} and 6\,^2D3/2_{3/2} states in 213^{213}Ra+^+ were measured. These values provide a benchmark for the required atomic theory. A lower limit of 232(4)232(4) ms for the lifetime of the metastable 6\,^2D5/2_{5/2} state was measured by optical shelving.Comment: 4.2 pages, 6 figures, 2 tables

    Isotope Shifts of the 6d\,^2D3/2 _{3/2}\, - 7p\,^2P1/2 _{1/2}\, Transition in Trapped Short-Lived 209−214^{209-214}Ra+^+

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    Laser spectroscopy of short-lived radium isotopes in a linear Paul trap has been performed. The isotope shifts of the 6d\,^2D3/2 _{3/2}\, - 7p\,^2P1/2 _{1/2}\, transition in 209−214^{209-214}Ra+^+ were measured, which are sensitive to the short range part of the atomic wavefunctions. The results are essential experimental input for improving the precision of atomic structure calculation. This is indispensable for parity violation in Ra+^+ aiming at the determination of the weak mixing angle.Comment: Accepted for publication in Physical Review A as a Rapid Communicatio

    Measurement of the half-life of the T=12\frac{1}{2} mirror decay of 19^{19}Ne and its implication on physics beyond the standard model

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    The 12+→12+\frac{1}{2}^+ \rightarrow \frac{1}{2}^+ superallowed mixed mirror decay of 19^{19}Ne to 19^{19}F is excellently suited for high precision studies of the weak interaction. However, there is some disagreement on the value of the half-life. In a new measurement we have determined this quantity to be T1/2T_{1/2} = 17.2832±0.0051(stat)17.2832 \pm 0.0051_{(stat)} ±0.0066(sys)\pm 0.0066_{(sys)} s, which differs from the previous world average by 3 standard deviations. The impact of this measurement on limits for physics beyond the standard model such as the presence of tensor currents is discussed.Comment: 5 pages, 3 figures, 1 tabl

    Development of a thermal ionizer as ion catcher

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    An effective ion catcher is an important part of a radioactive beam facility that is based on in-flight production. The catcher stops fast radioactive products and emits them as singly charged slow ions. Current ion catchers are based on stopping in He and H2_2 gas. However, with increasing intensity of the secondary beam the amount of ion-electron pairs created eventually prevents the electromagnetic extraction of the radioactive ions from the gas cell. In contrast, such limitations are not present in thermal ionizers used with the ISOL production technique. Therefore, at least for alkaline and alkaline earth elements, a thermal ionizer should then be preferred. An important use of the TRIμ\muP facility will be for precision measurements using atom traps. Atom trapping is particularly possible for alkaline and alkaline earth isotopes. The facility can produce up to 109^9 s−1^{-1} of various Na isotopes with the in-flight method. Therefore, we have built and tested a thermal ionizer. An overview of the operation, design, construction, and commissioning of the thermal ionizer for TRIμ\muP will be presented along with first results for 20^{20}Na and 21^{21}Na.Comment: 10 pages, 4 figures, XVth International Conference on Electromagnetic Isotope Separators and Techniques Related to their Applications (EMIS 2007

    On-line Excited-State Laser Spectroscopy of Trapped Short-Lived Ra+^+ Ions

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    As an important step towards an atomic parity violation experiment in one single trapped Ra+^+ ion, laser spectroscopy experiments were performed with on-line produced short-lived 212,213,214^{212,213,214}Ra+^+ ions. The isotope shift of the 6\,^2D3/2_{3/2}\,-\,7\,^2P1/2_{1/2} and 6\,^2D3/2_{3/2}\,-\,7\,^2P3/2_{3/2} transitions and the hyperfine structure constant of the 7\,^2S1/2_{1/2} and 6\,^2D3/2_{3/2} states in 213^{213}Ra+^+ were measured. These values provide a benchmark for the required atomic theory. A lower limit of 232(4)232(4) ms for the lifetime of the metastable 6\,^2D5/2_{5/2} state was measured by optical shelving

    Measurement of the Half-Life of the T = 1 2 Mirror Decay of Ne 19 and its Implication on Physics Beyond the Standard Model

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    The 1+/2 -> 1+/2 superallowed mixed mirror decay of Ne-19 to F-19 is excellently suited for high precision studies of the weak interaction. However, there is some disagreement on the value of the half-life. In a new measurement we have determined this quantity to be T-1/2 = 17.2832 +/- 0.0051((stat)) +/- 0.0066((syst)) s, which differs from the previous world average by 3 standard deviations. The impact of this measurement on limits for physics beyond the standard model such as the presence of tensor currents is discussed

    Cardiovascular development: towards biomedical applicability: Epicardium-derived cells in cardiogenesis and cardiac regeneration

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    During cardiogenesis, the epicardium grows from the proepicardial organ to form the outermost layer of the early heart. Part of the epicardium undergoes epithelial-mesenchymal transformation, and migrates into the myocardium. These epicardium- derived cells differentiate into interstitial fibroblasts, coronary smooth muscle cells, and perivascular fibroblasts. Moreover, epicardium-derived cells are important regulators of formation of the compact myocardium, the coronary vasculature, and the Purkinje fiber network, thus being essential for proper cardiac development. The fibrous structures of the heart such as the fibrous heart skeleton and the semilunar and atrioventricular valves also depend on a contribution of these cells during development. We hypothesise that the essential properties of epicardium-derived cells can be recapitulated in adult diseased myocardium. These cells can therefore be considered as a novel source of adult stem cells useful in clinical cardiac regeneration therapy

    The enchanted snake and the forbidden fruit: the ayahuasca ‘fairy tale’ tourist

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    This ethnographic study increases our understanding of Westerners seeking genuine fairy tale experiences of magic, transformation and enchantment within South American psychedelic ayahuasca tourism. Examining 63 tourists, this study shows how vision-based spirit sensegivers facilitate individuals in exorcising demons, to make sense of themselves as spiritual beings within an enchanted universe. However, and with this potion quickly wearing off upon returning to the West, tourists feel abandoned by their spirits, and disconnected from the fairy lands. Coupled with not wanting to re-experience intense inner tensions from stepping in and out of a fairy tale, further tourism is rejected. As such, ayahuasca tourism becomes a ‘forgotten’ fairy tale, rarely told
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