52 research outputs found
Intense beam of metastable Muonium
Precision spectroscopy of the Muonium Lamb shift and fine structure requires
a robust source of 2S Muonium. To date, the beam-foil technique is the only
demonstrated method for creating such a beam in vacuum. Previous experiments
using this technique were statistics limited, and new measurements would
benefit tremendously from the efficient 2S production at a low energy muon
( keV) facility. Such a source of abundant low energy has
only become available in recent years, e.g. at the Low-Energy Muon beamline at
the Paul Scherrer Institute. Using this source, we report on the successful
creation of an intense, directed beam of metastable Muonium. We find that even
though the theoretical Muonium fraction is maximal in the low energy range of
keV, scattering by the foil and transport characteristics of the beamline
favor slightly higher energies of keV. We estimate that
an event detection rate of a few events per second for a future Lamb shift
measurement is feasible, enabling an increase in precision by two orders of
magnitude over previous determinations
Impact of cross-section uncertainties on supernova neutrino spectral parameter fitting in the Deep Underground Neutrino Experiment
A primary goal of the upcoming Deep Underground Neutrino Experiment (DUNE) is
to measure the MeV neutrinos produced by a Galactic
core-collapse supernova if one should occur during the lifetime of the
experiment. The liquid-argon-based detectors planned for DUNE are expected to
be uniquely sensitive to the component of the supernova flux, enabling
a wide variety of physics and astrophysics measurements. A key requirement for
a correct interpretation of these measurements is a good understanding of the
energy-dependent total cross section for charged-current
absorption on argon. In the context of a simulated extraction of
supernova spectral parameters from a toy analysis, we investigate the
impact of modeling uncertainties on DUNE's supernova neutrino
physics sensitivity for the first time. We find that the currently large
theoretical uncertainties on must be substantially reduced
before the flux parameters can be extracted reliably: in the absence of
external constraints, a measurement of the integrated neutrino luminosity with
less than 10\% bias with DUNE requires to be known to about 5%.
The neutrino spectral shape parameters can be known to better than 10% for a
20% uncertainty on the cross-section scale, although they will be sensitive to
uncertainties on the shape of . A direct measurement of
low-energy -argon scattering would be invaluable for improving the
theoretical precision to the needed level.Comment: 25 pages, 21 figure
Lentisone, a New Phytotoxic Anthraquinone Produced by Ascochyta lentis, the Causal Agent of Ascochyta Blight in Lens culinaris
Highly-parallelized simulation of a pixelated LArTPC on a GPU
The rapid development of general-purpose computing on graphics processing units (GPGPU) is allowing the implementation of highly-parallelized Monte Carlo simulation chains for particle physics experiments. This technique is particularly suitable for the simulation of a pixelated charge readout for time projection chambers, given the large number of channels that this technology employs. Here we present the first implementation of a full microphysical simulator of a liquid argon time projection chamber (LArTPC) equipped with light readout and pixelated charge readout, developed for the DUNE Near Detector. The software is implemented with an end-to-end set of GPU-optimized algorithms. The algorithms have been written in Python and translated into CUDA kernels using Numba, a just-in-time compiler for a subset of Python and NumPy instructions. The GPU implementation achieves a speed up of four orders of magnitude compared with the equivalent CPU version. The simulation of the current induced on 10^3 pixels takes around 1 ms on the GPU, compared with approximately 10 s on the CPU. The results of the simulation are compared against data from a pixel-readout LArTPC prototype
High-precision Tunable Retardation Plate for Use with Visible and Ultra-violet Polarized Light
Polymerization of propene and 1,3-butadiene with Vanadyl(V) monoamidinate precatalysts and MAO or dialkylaluminum chloride cocatalysts
Two new vanadyl(V) amidinates have been synthesized and characterized by single crystal X-ray diffraction and H-1 NMR. The complexes are dimeric with Cl bridges and monodentate coordination of the amidinate ligand to pseudooctahedral vanadium. In the presence of organometallic compounds of aluminum, these vanadyl complexes promote polymerization of propene and 1,3-butadiene
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