This paper addresses the problem of estimating the infrastructure to be made available for refueling alternative fuel vehicles as a function of the profitability thresholds required by the ...investment. A methodology has been devised based on sales forecasts for alternative fuel vehicles. These methods use discrete choice models in which the factor of refueling infrastructure, rather than being considered simply as one more attribute of the model, acts as a constraint on the choice set for vehicle buyers. This methodology is used to estimate the infrastructure of hydrogen refueling stations and electricity charging stations for Spain (8,112 population centers) in 2030. Evolution of fuel cell vehicles over the years 2016 and 2030 is also estimated and compared with forecasts for countries such as France, Germany and the United Kingdom.
•With development of this optimization algorithm proposes a methodology to meet challenge posed by European Directive.•Methodology which corrects the effects of overestimating the AFV sales if infrastructure is considered as another attribute.•Methodology to locate new facilities depending on the protability parameter and its application to Spain Sensitivity analysis on the key parameter breakeven b, of the protability of the new facilities.•Compare the results obtained with the forecasts carried out for France, Germany, UK and Scandinavia for FCEV vehicles.
Abstract
IceCube, a cubic-kilometer array of optical sensors built to
detect atmospheric and astrophysical neutrinos between 1 GeV and
1 PeV, is deployed 1.45 km to 2.45 km below the surface of the
...ice sheet at the South Pole. The classification and reconstruction
of events from the in-ice detectors play a central role in the
analysis of data from IceCube. Reconstructing and classifying
events is a challenge due to the irregular detector geometry,
inhomogeneous scattering and absorption of light in the ice and,
below 100 GeV, the relatively low number of signal photons produced
per event. To address this challenge, it is possible to represent
IceCube events as point cloud graphs and use a Graph Neural Network
(GNN) as the classification and reconstruction method. The GNN is
capable of distinguishing neutrino events from cosmic-ray
backgrounds, classifying different neutrino event types, and
reconstructing the deposited energy, direction and interaction
vertex. Based on simulation, we provide a comparison in the
1 GeV–100 GeV energy range to the current state-of-the-art
maximum likelihood techniques used in current IceCube analyses,
including the effects of known systematic uncertainties. For
neutrino event classification, the GNN increases the signal
efficiency by 18% at a fixed background rate, compared to current
IceCube methods. Alternatively, the GNN offers a reduction of the
background (i.e. false positive) rate by over a factor 8 (to below
half a percent) at a fixed signal efficiency. For the
reconstruction of energy, direction, and interaction vertex, the
resolution improves by an average of 13%–20% compared to current
maximum likelihood techniques in the energy range of
1 GeV–30 GeV. The GNN, when run on a GPU, is capable of
processing IceCube events at a rate nearly double of the median
IceCube trigger rate of 2.7 kHz, which opens the possibility of
using low energy neutrinos in online searches for transient events.
Abstract
Since the discovery of a flux of high-energy astrophysical neutrinos, searches for their origins have focused primarily at TeV-PeV energies. Compared to sub-TeV searches, high-energy ...searches benefit from an increase in the neutrino cross section, improved angular resolution on the neutrino direction, and a reduced background from atmospheric neutrinos and muons. However, the focus on high energy does not preclude the existence of sub-TeV neutrino emission where IceCube retains sensitivity. Here we present the first all-flavor search from IceCube for transient emission of low-energy neutrinos, focusing on the energy region of 5.6-100 GeV using three years of data obtained with the IceCube-DeepCore detector. We find no evidence of transient neutrino emission in the data, thus leading to a constraint on the volumetric rate of astrophysical transient sources in the range of ∼ 705-2301 Gpc
-3
yr
-1
for sources following a subphotospheric energy spectrum with a mean energy of 100 GeV and a bolometric energy of 10
52
erg.
We present a search for a neutrino signal from dark matter self-annihilations in the Milky Way using the IceCube Neutrino Observatory (IceCube). In 1005 days of data we found no significant excess of ...neutrinos over the background of neutrinos produced in atmospheric air showers from cosmic ray interactions. We derive upper limits on the velocity averaged product of the dark matter self-annihilation cross section and the relative velocity of the dark matter particles
⟨
σ
A
v
⟩
. Upper limits are set for dark matter particle candidate masses ranging from 10 GeV up to 1 TeV while considering annihilation through multiple channels. This work sets the most stringent limit on a neutrino signal from dark matter with mass between 10 and 100 GeV, with a limit of
1.18
·
10
-
23
cm
3
s
-
1
for 100 GeV dark matter particles self-annihilating via
τ
+
τ
-
to neutrinos (assuming the Navarro–Frenk–White dark matter halo profile).
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract
The D-Egg, an acronym for “Dual optical sensors in an
Ellipsoid Glass for Gen2,” is one of the optical modules designed
for future extensions of the IceCube experiment at the South Pole.
The ...D-Egg has an elongated-sphere shape to maximize the
photon-sensitive effective area while maintaining a narrow diameter
to reduce the cost and the time needed for drilling of the
deployment holes in the glacial ice for the optical modules at
depths up to 2700 m.
The D-Egg design is utilized for the IceCube Upgrade, the next stage
of the IceCube project also known as IceCube-Gen2 Phase 1, where
nearly half of the optical sensors to be deployed are D-Eggs. With
two 8-inch high-quantum efficiency photomultiplier tubes (PMTs) per
module, D-Eggs offer an increased effective area while retaining the
successful design of the IceCube digital optical module (DOM). The
convolution of the wavelength-dependent effective area and the
Cherenkov emission spectrum provides an effective photodetection
sensitivity that is 2.8 times larger than that of IceCube DOMs. The
signal of each of the two PMTs is digitized using ultra-low-power
14-bit analog-to-digital converters with a sampling frequency of
240 MSPS, enabling a flexible event triggering, as well as seamless
and lossless event recording of single-photon signals to
multi-photons exceeding 200 photoelectrons within 10 ns. Mass
production of D-Eggs has been completed, with 277 out of the
310 D-Eggs produced to be used in the IceCube Upgrade. In
this paper, we report the design of the D-Eggs, as well as the
sensitivity and the single to multi-photon detection performance of
mass-produced D-Eggs measured in a laboratory using the built-in
data acquisition system in each D-Egg optical sensor module.
This Letter presents the results from pointlike neutrino source searches using ten years of IceCube data collected between April 6, 2008 and July 10, 2018. We evaluate the significance of an ...astrophysical signal from a pointlike source looking for an excess of clustered neutrino events with energies typically above ~1 TeV among the background of atmospheric muons and neutrinos. We perform a full-sky scan, a search within a selected source catalog, a catalog population study, and three stacked Galactic catalog searches. The most significant point in the northern hemisphere from scanning the sky is coincident with the Seyfert II galaxy NGC 1068, which was included in the source catalog search. The excess at the coordinates of NGC 1068 is inconsistent with background expectations at the level of 2.9σ after accounting for statistical trials from the entire catalog. The combination of this result along with excesses observed at the coordinates of three other sources, including TXS 0506+056, suggests that, collectively, correlations with sources in the northern catalog are inconsistent with background at 3.3σ significance. The southern catalog is consistent with background. Finally these results, all based on searches for a cumulative neutrino signal integrated over the 10 years of available data, motivate further study of these and similar sources, including time-dependent analyses, multimessenger correlations, and the possibility of stronger evidence with coming upgrades to the detector.
Inelasticity, the fraction of a neutrino's energy transferred to hadrons, is a quantity of interest in the study of astrophysical and atmospheric neutrino interactions at multi-TeV energies with ...IceCube. In this work, a sample of contained neutrino interactions in IceCube is obtained from five years of data and classified as 2650 tracks and 965 cascades. Tracks arise predominantly from charged-current νμ interactions, and we demonstrate that we can reconstruct their energy and inelasticity. The inelasticity distribution is found to be consistent with the calculation of Cooper-Sarkar et al. across the energy range from ~1 to ~100 TeV. Along with cascades from neutrinos of all flavors, we also perform a fit over the energy, zenith angle, and inelasticity distribution to characterize the flux of astrophysical and atmospheric neutrinos. The energy spectrum of diffuse astrophysical neutrinos is described well by a power law in both track and cascade samples, and a best-fit index γ = 2.62 ± 0.07 is found in the energy range from 3.5 TeV to 2.6 PeV. Limits are set on the astrophysical flavor composition and are compatible with a ratio of ($\frac{1}{3}$ : $\frac{1}{3}$ : $\frac{1}{3}$)⊕. Exploiting the distinct inelasticity distribution of νμ and $\bar{ν}_μ$ interactions, the atmospheric νμ to $\bar{ν}_μ$ flux ratio in the energy range from 770 GeV to 21 TeV is found to be 0.77$_{-0.25}^{+0.44}$ times the calculation by Honda et al. Lastly, the inelasticity distribution is also sensitive to neutrino charged-current charm production. The data are consistent with a leading-order calculation, with zero charm production excluded at 91% confidence level. Future analyses of inelasticity distributions may probe new physics that affects neutrino interactions both in and beyond the Standard Model.
Many Galactic sources of gamma rays, such as supernova remnants, are expected to produce neutrinos with a typical energy cutoff well below 100 TeV. For the IceCube Neutrino Observatory located at the ...South Pole, the southern sky, containing the inner part of the Galactic plane and the Galactic Center, is a particularly challenging region at these energies, because of the large background of atmospheric muons. In this paper, we present recent advancements in data selection strategies for track-like muon neutrino events with energies below 100 TeV from the southern sky. The strategies utilize the outer detector regions as veto and features of the signal pattern to reduce the background of atmospheric muons to a level which, for the first time, allows IceCube searching for point-like sources of neutrinos in the southern sky at energies between 100 GeV and several TeV in the muon neutrino charged current channel. We report no significant clustering of neutrinos above background expectation was observed in four years of data recorded with the completed IceCube detector. Upper limits on the neutrino flux for a number of spectral hypotheses are reported for a list of astrophysical objects in the southern hemisphere.
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