53,915 research outputs found
Radiological control procedures applicable to radioisotope thermoelectric generator SNAP-27. Volume 1 - Normal operations
Radiological control procedures applicable to transport, handling, and storage of the thermoelectric generator SNAP 27 prior to launch during normal condition
Radiological control procedures applicable to radioisotope thermoelectric generator SNAP-27. Volume 2 - Radiological emergencies
Radiological control procedures for transportation, handling, and storage of SNAP 27 thermoelectric generator in radiological emergencie
On the Interpretation of the Atmospheric Neutrino Data in Terms of Flavor Changing Neutrino Interactions
Flavour changing (FC) neutrino-matter interactions have been proposed as a
solution to the atmospheric neutrino anomaly. Here we perform the analysis of
the full set of the recent 52 kTy Super-Kamiokande atmospheric neutrino data,
including the zenith angle distribution of the contained events as well as the
higher energy upward-going stopping and through-going muon events. Our results
show that the FC mechanism can describe the full data sample with a
chi^2_{min}=44/(33 d.o.f) which is acceptable at the 90% confidence level. The
combined analysis confines the amount of FC to be either close to maximal or to
the level of about (10-50)%.Comment: 15 pages, 4 Postscript figures, uses ReVTeX. Updated analysis to 52
kTy Super-Kamiokande data. A new figure for the up-down asymmetry is
included. Some comments and references are adde
Global three-neutrino oscillation analysis of neutrino data
A global analysis of the solar, atmospheric and reactor neutrino data is
presented in terms of three-neutrino oscillations. We include the most recent
solar neutrino rates of Homestake, SAGE, GALLEX and GNO, as well as the recent
1117 day Super-Kamiokande data sample, including the recoil electron energy
spectrum both for day and night periods and we treat in a unified way the full
parameter space for oscillations, correctly accounting for the transition from
the matter enhanced (MSW) to the vacuum oscillations regime. Likewise, we
include in our description conversions with . For the
atmospheric data we perform our analysis of the contained events and the
upward-going -induced muon fluxes, including the previous data samples of
Frejus, IMB, Nusex, and Kamioka experiments as well as the full 71 kton-yr
(1144 days) Super-Kamiokande data set, the recent 5.1 kton-yr contained events
of Soudan2 and the results on upgoing muons from the MACRO detector. We first
present the allowed regions of solar and atmospheric oscillation parameters
, and , ,
respectively, as a function of and determine the constraints from
atmospheric and solar data on the mixing angle , common to solar
and atmospheric analyses. We also obtain the allowed ranges of parameters from
the full five-dimensional combined analysis of the solar, atmospheric and
reactor data.Comment: 56 pages, 21 postscript figures. Some misprints corrected and new
references added. Chooz limit included in Fig.21. Final version to appear in
Phys. Rev.
Crystal engineering using functionalized adamantane
We performed a first principles investigation on the structural, electronic,
and optical properties of crystals made of chemically functionalized adamantane
molecules. Several molecular building blocks, formed by boron and nitrogen
substitutional functionalizations, were considered to build zincblende and
wurtzite crystals, and the resulting structures presented large bulk moduli and
cohesive energies, wide and direct bandgaps, and low dielectric constants
(low- materials). Those properties provide stability for such
structures up to room temperature, superior to those of typical molecular
crystals. This indicates a possible road map for crystal engineering using
functionalized diamondoids, with potential applications ranging from space
filling between conducting wires in nanodevices to nano-electro-mechanical
systems
Seasonal Dependence in the Solar Neutrino Flux
MSW solutions of the solar neutrino problem predict a seasonal dependence of
the zenith angle distribution of the event rates, due to the non-zero latitude
at the Super-Kamiokande site. We calculate this seasonal dependence and compare
it with the expectations in the no-oscillation case as well as just-so
scenario, in the light of the latest Super-Kamiokande 708-day data. The
seasonal dependence can be sizeable in the large mixing angle MSW solution and
would be correlated with the day-night effect. This may be used to discriminate
between MSW and just-so scenarios and should be taken into account in refined
fits of the data.Comment: 4 pages, latex, RevTeX, two postscript figure
Hot electron transport in Ballistic Electron Emission Spectroscopy: band structure effects and k-space currents
Using a Green's function approach, we investigate band structure effects in
the BEEM current distribution in reciprocal space. In the elastic limit, this
formalism provides a 'parameter free' solution to the BEEM problem. At low
temperatures, and for thin metallic layers, the elastic approximation is enough
to explain the experimental I(V) curves at low voltages. At higher voltages
inelastic effects are approximately taken into account by introducing an
effective RPA-electron lifetime, much in similarity with LEED theory. For thick
films, however, additional damping mechanisms are required to obtain agreement
with experiment.Comment: 4 pages, 3 postscript figures, revte
The State of the Circumstellar Medium Surrounding Gamma-Ray Burst Sources and its Effect on the Afterglow Appearance
We present a numerical investigation of the contribution of the presupernova
ejecta of Wolf-Rayet stars to the environment surrounding gamma-ray bursts
(GRBs), and describe how this external matter can affect the observable
afterglow characteristics. An implicit hydrodynamic calculation for massive
stellar evolution is used here to provide the inner boundary conditions for an
explicit hydrodynamical code to model the circumstellar gas dynamics. The
resulting properties of the circumstellar medium are then used to calculate the
deceleration of a relativistic, gas-dynamic jet and the corresponding afterglow
light curve produced as the shock wave propagates through the shocked-wind
medium. We find that variations in the stellar wind drive instabilities that
may produce radial filaments in the shocked-wind region. These comet-like tails
of clumps could give rise to strong temporal variations in the early afterglow
lightcurve. Afterglows may be expected to differ widely among themselves,
depending on the angular anisotropy of the jet and the properties of the
stellar progenitor; a wide diversity of behaviors may be the rule, rather than
the exception.Comment: 17 pages, 7 figures, ApJ in pres
Implications of the first detection of coherent elastic neutrino-nucleus scattering (CEvNS) with Liquid Argon
The CENNS-10 experiment of the COHERENT collaboration has recently reported
the first detection of coherent-elastic neutrino-nucleus scattering (CEvNS) in
liquid Argon with more than significance. In this work, we exploit
the new data in order to probe various interesting parameters which are of key
importance to CEvNS within and beyond the Standard Model. A dedicated
statistical analysis of these data shows that the current constraints are
significantly improved in most cases. We derive a first measurement of the
neutron rms charge radius of Argon, and also an improved determination of the
weak mixing angle in the low energy regime. We also update the constraints on
neutrino non-standard interactions, electromagnetic properties and light
mediators with respect to those derived from the first COHERENT-CsI data.Comment: discussion expanded including light mediators and nuclear
uncertainties, figures added, references added. V3: Fig. 7 corrected,
conclusions unchange
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