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A bstract The Neutrino Experiment with a Xenon TPC (NEXT) searches for the neutrinoless double-beta (0 νββ ) decay of 136 Xe using high-pressure xenon gas TPCs with electroluminescent amplification. A scaled-up version of this technology with about 1 tonne of enriched xenon could reach in less than 5 years of operation a sensitivity to the half-life of 0 νββ decay better than 10 27 years, improving the current limits by at least one order of magnitude. This prediction is based on a well-understood background model dominated by radiogenic sources. The detector concept presented here represents a first step on a compelling path towards sensitivity to the parameter space defined by the inverted ordering of neutrino masses, and beyond.

The imaging of individual Ba 2+ ions in high pressure xenon gas is one possible way to attain background-free sensitivity to neutrinoless double beta decay and hence establish the Majorana nature of the neutrino. In this paper we demonstrate selective single Ba 2+ ion imaging inside a high-pressure xenon gas environment. Ba 2+ ions chelated with molecular chemosensors are resolved at the gas-solid interface using a diffraction-limited imaging system with scan area of 1 × 1 cm 2 located inside 10 bar of xenon gas. This form of microscopy represents key ingredient in the development of barium tagging for neutrinoless double beta decay searches in 136 Xe. This also provides a new tool for studying the photophysics of fluorescent molecules and chemosensors at the solid-gas interface to enable bottom-up design of catalysts and sensors. Barium tagging is a key ingredient for future detectors of neutrinoless double beta decay in low-background environments. Here, the authors demonstrate fluorescence imaging of single Ba2+ ions in high pressure Xenon gas, by comparing activity between Ba2+ chelated and unchelated samples of crown-ether chemosensors.

The imaging of individual Ba2+ ions in high pressure xenon gas is one possible way to attain background-free sensitivity to neutrinoless double beta decay and hence establish the Majorana nature of the neutrino. In this paper we demonstrate selective single Ba2+ ion imaging inside a high-pressure xenon gas environment. Ba2+ ions chelated with molecular chemosensors are resolved at the gas-solid interface using a diffraction-limited imaging system with scan area of 1 × 1 cm2 located inside 10 bar of xenon gas. This form of microscopy represents key ingredient in the development of barium tagging for neutrinoless double beta decay searches in 136Xe. This also provides a new tool for studying the photophysics of fluorescent molecules and chemosensors at the solid-gas interface to enable bottom-up design of catalysts and sensors.

We present evidence of non-excimer-based secondary scintillation in gaseous xenon, obtained using both the NEXT-White time projection chamber (TPC) and a dedicated setup. Detailed comparison with first-principle calculations allows us to assign this scintillation mechanism to neutral bremsstrahlung (NBrS), a process that is postulated to exist in xenon that has been largely overlooked. For photon emission below 1000 nm, the NBrS yield increases from about10−2photon/e−cm−1bar−1at pressure-reduced electric field values of50Vcm−1bar−1to above3×10−1photon/e−cm−1bar−1at500Vcm−1bar−1. Above1.5kVcm−1bar−1, values that are typically employed for electroluminescence, it is estimated that NBrS is present with an intensity around1photon/e−cm−1bar−1, which is about 2 orders of magnitude lower than conventional, excimer-based electroluminescence. Despite being fainter than its excimeric counterpart, our calculations reveal that NBrS causes luminous backgrounds that can interfere, in either gas or liquid phase, with the ability to distinguish and/or to precisely measure low primary-scintillation signals (S1). In particular, we show this to be the case in the “buffer” region, where keeping the electric field below the electroluminescence threshold does not suffice to extinguish secondary scintillation. The electric field leakage in this region should be mitigated to avoid intolerable levels of NBrS emission. Furthermore, we show that this new source of light emission opens up a viable path toward obtaining S2 signals for discrimination purposes in future single-phase liquid TPCs for neutrino and dark matter physics, with estimated yields up to20–50photons/e−cm−1.

A bstract Double electron capture by proton-rich nuclei is a second-order nuclear process analogous to double beta decay. Despite their similarities, the decay signature is quite different, potentially providing a new channel to measure the hypothesized neutrinoless mode of these decays. The Standard-Model-allowed two-neutrino double electron capture (2 νEC EC ) has been predicted for a number of isotopes, but only observed in 78 Kr, 130 Ba and, recently, 124 Xe. The sensitivity to this decay establishes a benchmark for the ultimate experimental goal, namely the potential to discover also the lepton-number-violating neutrinoless version of this process, 0 νEC EC . Here we report on the current sensitivity of the NEXT-White detector to 124 Xe 2 νEC EC and on the extrapolation to NEXT-100. Using simulated data for the 2 νEC EC signal and real data from NEXT-White operated with 124 Xe-depleted gas as background, we define an optimal event selection that maximizes the NEXT-White sensitivity. We estimate that, for NEXT-100 operated with xenon gas isotopically enriched with 1 kg of 124 Xe and for a 5-year run, a sensitivity to the 2 νEC EC half-life of 6 × 10 22 y (at 90% confidence level) or better can be reached.

The Neutrino Experiment with a Xenon TPC (NEXT) searches for the neutrinoless double-beta (0νββ) decay of 136Xe using high-pressure xenon gas TPCs with electroluminescent amplification. A scaled-up version of this technology with about 1 tonne of enriched xenon could reach in less than 5 years of operation a sensitivity to the half-life of 0νββ decay better than 1027 years, improving the current limits by at least one order of magnitude. This prediction is based on a well-understood background model dominated by radiogenic sources. The detector concept presented here represents a first step on a compelling path towards sensitivity to the parameter space defined by the inverted ordering of neutrino masses, and beyond.

Throughout the world of business, there are a plethora of studies and guides for employee engagement. The research is deep and wide for the causes and effects of an engaged workforce and the skills it takes to rally a work culture. However, in the realm of Christian higher education, there is very little advice or instruction for the engagement of faculty and staff, nor is there literature to support why it is important. The purpose of this study was to build upon the work of the Best Christian Workplaces Institute and their Employee Engagement and Organizational Culture Survey to discover ways in which Christian institutions have been successful in raising their workplace engagement. An explanatory mixed methods design was used involving the collection of qualitative data after the analysis of quantitative data provided by Best Christian Workplaces Institute. In the first, quantitative phase of the study, the simple bar graphs for each institution show the progression by category of the Best Christian Workplaces Institute FLOURISH model. Next, a qualitative phase was conducted through personal interviews to explore the validity of the data on each of the institutions from the perspective of administrators and mid-managers on site. The goal of this exploratory follow-up was to build upon the quantitative results through Appreciative Inquiry, “often conducted by people who are interested in facilitating change in their work, community, or family” (Merriam & Tisdell, 2016, p. 4). Although each institution was unique in its approach and success, there were common themes that served to categorize the findings: (a) engagement efforts and results, highlighting the intentional efforts of the university to address concerns brought to light through the survey as well as the results that ensued; (b) institutional spiritual vitality, focusing on the reciprocal relationship between an engaged workforce and campus spiritual climate; and (c) influence of university mission, giving attention to the impact of mission integrity for the work of all institutions, both internally and externally.

We present a tunable metal ion beam that delivers controllable ion currents in the picoamp range for testing of dry-phase ion sensors. Ion beams are formed by sequential atomic evaporation and single or multiple electron impact ionization, followed by acceleration into a sensing region. Controllability of the ionic charge state is achieved through tuning of electrode potentials that influence the retention time in the ionization region. Barium, lead, and cobalt samples have been used to test the system, with ion currents identified and quantified using a quadrupole mass analyzer. Realization of a clean \\(Ba^2+\\) ion beam within a bench-top system represents an important technical advance toward the development and characterization of barium tagging systems for neutrinoless double beta decay searches in xenon gas. This system also provides a testbed for investigation of novel ion sensing methodologies for environmental assay applications, with dication beams of Pb\\(^2+\\) and Cd\\(^2+\\) also demonstrated for this purpose.

We report a measurement of the half-life of the \\(^136\\)Xe two-neutrino double beta decay performed with a novel direct background subtraction technique. The analysis relies on the data collected with the NEXT-White detector operated with \\(^136\\)Xe-enriched and \\(^136\\)Xe-depleted xenon, as well as on the topology of double-electron tracks. With a fiducial mass of only 3.5 kg of Xe, a half-life of \\(2.34^+0.80_-0.46(stat)^+0.30_-0.17(sys)10^21~yr\\) is derived from the background-subtracted energy spectrum. The presented technique demonstrates the feasibility of unique background-model-independent neutrinoless double beta decay searches.