The Pyh\"asalmi mine is uniquely suited to host new generation of large-scale
underground experiments. It was chosen both by the LAGUNA-LBNO and by the LENA
Collaboration as the preferred site for a ...giant neutrino observatory.
Regrettably, none of these projects got funded. The termination of the
underground excavations in the fall of 2019 marks an important milestone. To
maintain the infrastructure in good condition a new sponsor must be found:
either a large-scale scientific project or new commercial operation. The
considered alternatives for the commercial used of the mine include a
pumped-storage hydroelectricity plant and a high-security underground
data-storage centre. Without a new sponsor the ongoing experiments, including
the cosmic-ray experiment EMMA and the study of 14C content in liquid
scintillators, have to be completed within the next few years.
A systematic investigation of Planacon MCP-PMTs was performed using 64 XP85002/FIT-Q photosensors. These devices are equipped with microchannel plates of reduced resistance. Results of a study of ...their gain stability over time and saturation level in terms of the average anode current are presented. This information allows one to determine the lower limit of the MCP resistance for stable Planacon operation. The spread of the electron multiplication characteristics for the entire production batch is also presented, indicating the remarkably low voltage requirements of these MCP-PMTs. Detection efficiency and noise characteristics, such as dark count rate and afterpulsing level, are also reviewed.
To maximize the light yield of the liquid scintillator (LS) for the Jiangmen Underground Neutrino Observatory (JUNO), a 20 t LS sample was produced in a pilot plant at Daya Bay. The optical ...properties of the new LS in various compositions were studied by replacing the gadolinium-loaded LS in one antineutrino detector. The concentrations of the fluor, PPO, and the wavelength shifter, bis-MSB, were increased in 12 steps from 0.5 g/L and <0.01 mg/L to 4 g/L and 13 mg/L, respectively. The numbers of total detected photoelectrons suggest that, with the optically purified solvent, the bis-MSB concentration does not need to be more than 4 mg/L. To bridge the one order of magnitude in the detector size difference between Daya Bay and JUNO, the Daya Bay data were used to tune the parameters of a newly developed optical model. Then, the model and tuned parameters were used in the JUNO simulation. This enabled to determine the optimal composition for the JUNO LS: purified solvent LAB with 2.5 g/L PPO, and 1 to 4 mg/L bis-MSB.
We have measured and compared the characteristics of ALD-coated Planacon MCP-PMTs (XP85112/A1-Q-L) with their non-ALD counterparts (XP85012/A1-Q). While the later show excellent performance, the ...ALD-coated sensors have surprisingly low current saturation levels (~two orders of magnitude lower than expected) and extremely high gain recovery time (more than 7 orders of magnitude higher than expected). We suspect that these problems might be caused by the unexpected side-effects of the ALD process. To make a definite conclusion, more samples need to be tested, preferably from different production runs. If our observation were confirmed, it would mean a serious technological setback for ALD-coated MCP-PMTs.
We are going to perform a series of measurements where the 14C/12 C ratio will be measured from several liquid scintillator samples with a dedicated setup. The setup is designed with the aim of ...measuring ratios smaller than 10-18. Measurements take place in two underground laboratories: in the Baksan Neutrino Observatory, Russia and in the Pyhäsalmi mine, Finland. In Baksan the measurements started in 2015 and in Pyhäsalmi they start in the beginning of 2015. In order to fully understand the operation of the setup and its background contributions a development of simulation packages has also been started. Low-energy neutrino detection with a liquid scintillator requires that the intrinsic 14C content in the liquid is extremely low. In the Borexino CTF detector at Gran Sasso, Italy the 14C/12C ratio of 2 × 10-18 has been achieved being the lowest 14C concentration ever measured. In principle, the older the oil or gas source that the liquid scintillator is derived of and the deeper it situates, the smaller the 14C/12C ratio is supposed to be. This, however, is not generally the case, and the ratio is probably determined by the U and Th content of the local environment.
The Pyh\"asalmi mine is uniquely suited to host new generation of large-scale underground experiments. It was chosen both by the LAGUNA-LBNO and by the LENA Collaboration as the preferred site for a ...giant neutrino observatory. Regrettably, none of these projects got funded. The termination of the underground excavations in the fall of 2019 marks an important milestone. To maintain the infrastructure in good condition a new sponsor must be found: either a large-scale scientific project or new commercial operation. The considered alternatives for the commercial used of the mine include a pumped-storage hydroelectricity plant and a high-security underground data-storage centre. Without a new sponsor the ongoing experiments, including the cosmic-ray experiment EMMA and the study of 14C content in liquid scintillators, have to be completed within the next few years.
The next generation neutrino observatory proposed by the LBNO collaboration
will address fundamental questions in particle and astroparticle physics. The
experiment consists of a far detector, in its ...first stage a 20 kt LAr double
phase TPC and a magnetised iron calorimeter, situated at 2300 km from CERN and
a near detector based on a high-pressure argon gas TPC. The long baseline
provides a unique opportunity to study neutrino flavour oscillations over their
1st and 2nd oscillation maxima exploring the $L/E$ behaviour, and
distinguishing effects arising from $\delta_{CP}$ and matter.
In this paper we have reevaluated the physics potential of this setup for
determining the mass hierarchy (MH) and discovering CP-violation (CPV), using a
conventional neutrino beam from the CERN SPS with a power of 750 kW. We use
conservative assumptions on the knowledge of oscillation parameter priors and
systematic uncertainties. The impact of each systematic error and the precision
of oscillation prior is shown. We demonstrate that the first stage of LBNO can
determine unambiguously the MH to $>5\sigma$C.L. over the whole phase space. We
show that the statistical treatment of the experiment is of very high
importance, resulting in the conclusion that LBNO has $\sim$ 100% probability
to determine the MH in at most 4-5 years of running. Since the knowledge of MH
is indispensable to extract $\delta_{CP}$ from the data, the first LBNO phase
can convincingly give evidence for CPV on the $3\sigma$C.L. using today's
knowledge on oscillation parameters and realistic assumptions on the systematic
uncertainties.
Nursing education reinvented Slupecki, Susan M
Imprint (New York, New York),
2008 Feb-Mar, Letnik:
55, Številka:
2
Magazine Article
The students at UT Arlington School of Nursing's Smart Hospital' are having a different experience than did the students who worked with "Mrs. Chase" (see page 52). But the end result is the same--to ...better patient advocacy and outcomes.
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