Abstract $$^{180\textrm{m}}\text {Ta}$$ 180 m Ta is the longest-lived metastable state presently known. Its decay has not been observed yet. In this work, we report a new result on the decay of ...$$^{180\textrm{m}}\text {Ta}$$ 180 m Ta obtained with a 2015.12-g tantalum sample measured for 527.7 d with an ultra-low background HPGe detector in the STELLA laboratory of the Laboratori Nazionali del Gran Sasso (LNGS), in Italy. Before the measurement, the sample has been stored deep-underground for ten years, resulting in subdominant background contributions from cosmogenically activated $$^{182}\text {Ta}$$ 182 Ta . We observe no signal in the regions of interest and set half-life limits on the process for the two channels EC and $$\beta ^-$$ β - : $$T_{1/2,~\textrm{EC}}> 1.6 \times 10^{18}$$ T 1 / 2 , EC > 1.6 × 10 18 year and $$T_{1/2,~\beta ^-}> 1.1\times 10^{18}$$ T 1 / 2 , β - > 1.1 × 10 18 year (90% C. I.), respectively. We also set the limit on the $$\gamma $$ γ de-excitation / IC channel: $$T_{1/2,~\textrm{IC}}> 4.1 \times 10^{15}$$ T 1 / 2 , IC > 4.1 × 10 15 year (90% C. I.). These are, as of now, the most stringent bounds on the decay of $$^{180\textrm{m}}\text {Ta}$$ 180 m Ta worldwide. Finally, we test the hypothetical scenarios of de-excitation of $$^{180\textrm{m}}\text {Ta}$$ 180 m Ta by cosmological Dark Matter and constrain new parameter space for strongly-interacting dark-matter particle with mass up to $$10^5$$ 10 5 GeV.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Proton captures on Mg isotopes play an important role in the Mg-Al cycle active in stellar H-burning regions. In particular, low-energy nuclear resonances in the {sup 25}Mg(p, {gamma}){sup 26}Al ...reaction affect the production of radioactive {sup 26}Al{sup gs} as well as the resulting Mg/Al abundance ratio. Reliable estimations of these quantities require precise measurements of the strengths of low-energy resonances. Based on a new experimental study performed at the Laboratory for Underground Nuclear Astrophysics, we provide revised rates of the {sup 25}Mg(p, {gamma}){sup 26}Al{sup gs} and the {sup 25}Mg(p, {gamma}){sup 26}Al {sup m} reactions with corresponding uncertainties. In the temperature range 50-150 MK, the new recommended rate of {sup 26}Al {sup m} production is up to five times higher than previously assumed. In addition, at T = 100 MK, the revised total reaction rate is a factor of two higher. Note that this is the range of temperature at which the Mg-Al cycle operates in a H-burning zone. The effects of this revision are discussed. Due to the significantly larger {sup 25}Mg(p, {gamma}){sup 26}Al {sup m} rate, the estimated production of {sup 26}Al{sup gs} in H-burning regions is less efficient than previously obtained. As a result, the new rates should imply a smaller contribution from Wolf-Rayet stars to the galactic {sup 26}Al budget. Similarly, we show that the asymptotic giant branch (AGB) extra-mixing scenario does not appear able to explain the most extreme values of {sup 26}Al/{sup 27}Al, i.e., >10{sup -2}, found in some O-rich presolar grains. Finally, the substantial increase of the total reaction rate makes the hypothesis of self-pollution by massive AGBs a more robust explanation for the Mg-Al anticorrelation observed in globular-cluster stars.
The burden of disease is borne by those who suffer as patients but also by society at large, including health service providers. That burden is felt most severely in parts of the world where there is ...no infrastructure, or foreseeable prospects of any, to change the status quo without external support. Poverty, disease and inequality pervade all the activities of daily living in low‐income regions and are inextricably linked. External interventions may not be the most appropriate way to impact on this positively in all circumstances, but targeted programmes to build social capital, within and by countries, are more likely to be sustainable. By these means, basic oral healthcare, underpinned by the primary healthcare approach, can be delivered to more equitably address needs and demands. Education is fundamental to building knowledge‐based economies but is often lacking in such regions even at primary and secondary level. Provision of private education at tertiary level may also introduce its own inequities. Access to distance learning and community‐based practice opens opportunities and is more likely to encourage graduates to work in similar areas. Recruitment of faculty from minority groups provides role models for students from similar backgrounds but all faculty staff must be involved in supporting and mentoring students from marginalized groups to ensure their retention. The developed world has to act responsibly in two crucial areas: first, not to exacerbate the shortage of skilled educators and healthcare workers in emerging economies by recruiting their staff; second, they must offer educational opportunities at an economic rate. Governments need to lead on developing initiatives to attract, support and retain a competent workforce.
We introduce the LUNA neutron detector array developed for the investigation of the 13C(α, n)16O reaction towards its astrophysical s-process Gamow peak in the low-background environment of the ...Laboratori Nazionali del Gran Sasso (LNGS). Eighteen 3He counters are arranged in two different configurations (in a vertical and a horizontal orientation) to optimize neutron detection efficiency, target handling and target cooling over the investigated energy range Eα,lab=300−400 keV (En=2.2−2.6MeV in emitted neutron energy). As a result of the deep underground location, the passive shielding of the setup and active background suppression using pulse shape discrimination, we reached a total background rate of 1.23±0.12 counts/hour. This resulted in an improvement of two orders of magnitude over the state of the art allowing a direct measurement of the 13C(α, n)16O cross-section down to Eα,lab=300 keV. The absolute neutron detection efficiency of the setup was determined using the 51V(p,n)51Cr reaction and an AmBe radioactive source, and completed with a Geant4 simulation. We determined a (34 ± 3)% and (38 ± 3)% detection efficiency for the vertical and horizontal configurations, respectively, for En=2.4MeV neutrons.
The clash between the religious right and the secular left undermines any serious debate about the role of religion in American public life. Such strident cultural rhetoric often ignores the positive ...contributions of America's many religions. By contrast, this volume celebrates America's religious diversity, demonstrating that religious pluralism is actually one of democracy's basic building blocks. Taking Religious Pluralism Seriously expands on Barbara A. McGraw's framework for understanding religious participation in public life-a two-tiered public forum, consisting of the civic public forum and the conscientious public forum. The chapters explore how diverse religious communities and traditions, including ''newer'' and marginalized religions, can make a meaningful contribution to American society and politics.
In this contribution, the motivations for a Focus Point on the future nuclear physics researches in the Italian laboratories are described. The organization of the preliminary workshops and of the ...final reports in this series is described.
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