58 research outputs found
Extreme Energy Cosmic Rays (EECR) Observation Capabilities of an "Airwatch from Space'' Mission
The longitudinal development and other characteristics of the EECR induced
atmospheric showers can be studied from space by detecting the fluorescence
light induced in the atmospheric nitrogen. According to the Airwatch concept a
single fast detector can be used for measuring both intensity and time
development of the streak of fluorescence light produced by the atmospheric
shower induced by an EECR. In the present communication the detection
capabilities for the EECR observation from space are discussed.Comment: 3 pages (LaTeX). To appear in the Proceedings of TAUP'9
Neutrino masses: From fantasy to facts
Theory suggests the existence of neutrino masses, but little more. Facts are
coming close to reveal our fantasy: solar and atmospheric neutrino data
strongly indicate the need for neutrino conversions, while LSND provides an
intriguing hint. The simplest ways to reconcile these data in terms of neutrino
oscillations invoke a light sterile neutrino in addition to the three active
ones. Out of the four neutrinos, two are maximally-mixed and lie at the LSND
scale, while the others are at the solar mass scale. These schemes can be
distinguished at neutral-current-sensitive solar & atmospheric neutrino
experiments. I discuss the simplest theoretical scenarios, where the lightness
of the sterile neutrino, the nearly maximal atmospheric neutrino mixing, and
the generation of & all follow
naturally from the assumed lepton-number symmetry and its breaking. Although
the most likely interpretation of the present data is in terms of
neutrino-mass-induced oscillations, one still has room for alternative
explanations, such as flavour changing neutrino interactions, with no need for
neutrino mass or mixing. Such flavour violating transitions arise in theories
with strictly massless neutrinos, and may lead to other sizeable flavour
non-conservation effects, such as , conversion in
nuclei, unaccompanied by neutrino-less double beta decay.Comment: 33 pages, latex, 16 figures. Invited Talk at Ioannina Conference,
Symmetries in Intermediate High Energy Physics and its Applications, Oct.
1998, to be published by Springer Tracts in Modern Physics. Festschrift in
Honour of John Vergados' 60th Birthda
The small satellite NINA-MITA to study galactic and solar cosmic rays in low-altitude polar orbit
Abstract The satellite MITA, carrying on board the scientific payload NINA-2, was launched on July the 15th, 2000 from the cosmodrome of Plesetsk (Russia) with a Cosmos-3M rocket. The satellite and the payload are currently operating within nominal parameters. NINA-2 is the first scientific payload for the technological flight of the Italian small satellite MITA. The detector used in this mission is identical to the one already flying on the Russian satellite Resurs-O1 n.4 in a 840-km sun-synchronous orbit, but makes use of the extensive computer and telemetry capabilities of MITA bus to improve the active data acquisition time. NINA physics objectives are to study cosmic nuclei from hydrogen to iron in the energy range between 10 MeV/n and 1 GeV/n during the years 2000â2003, that is the solar maximum period. The device is capable of charge identification up to iron with isotope sensitivity up to oxigen. The 87.3 degrees, 460 km altitude polar orbit allows investigations of cosmic rays of solar and galactic origin, so to study long and short term solar transient phenomena, and the study of the trapped radiation at higher geomagnetic cutoff
Light Isotope Abundances in Solar Energetic Particles measured by the Space Instrument NINA
This article reports nine Solar Energetic Particle events detected by the
instrument NINA between October 1998 and April 1999. NINA is a silicon-based
particle detector mounted on-board the Russian satellite Resurs-01-N4, which
has flown at an altitude of about 800 km in polar inclination since July 1998.
For every solar event the power-law He4 spectrum across the energy interval
10--50 MeV/n was reconstructed, and spectral indexes, gamma, from 1.8 to 6.8
extracted. Data of He3 and He4 were used to determine the He3/He4 ratio, that
for some SEP events indicated an enrichment in He3. For the 1998 November 7
event the ratio reached a maximum value of 0.33+- 0.06, with spectral indexes
of gamma = 2.5 +- 0.6 and gamma = 3.7 +- 0.3 for He3 and He4, respectively. The
He3/He4 ratio averaged over the remaining events was 0.011 +- 0.004. For all
events the deuterium-to-proton ratio was determined. The average value over all
events was (3.9+-1.4) 10^{-5} across the energy interval 9--12 MeV/n. For one
event (1998 November 24) this ratio yielded approximately 10 times higher than
normal coronal values. Upper limits on the H3/H1 counting ratio for all events
were determined. For the 1998 November 14 SEP event the high flux of heavy
particles detected made it possible to reconstruct the carbon and oxygen flux.Comment: 42 pages, 14 figures, submitted to Journal of Geophysical Researc
In-Orbit Performance of the Space Telescope NINA and GCR Flux Measurements
The NINA apparatus, on board the Russian satellite Resurs-01 n.4, has been in
polar orbit since 1998 July 10, at an altitude of 840 km. Its main scientific
task is to study the galactic, solar and anomalous components of cosmic rays in
the energy interval 10--200 MeV/n. In this paper we present a description of
the instrument and its basic operating modes. Measurements of Galactic Cosmic
Ray spectra will also be shown.Comment: 38 pages, 10 figures, accepted for publication in the ApJ
The Cosmic-Ray antiproton flux between 3 and 49 GeV
We report on a new measurement of the cosmic ray antiproton spectrum. The
data were collected by the balloon-borne experiment CAPRICE98 which was flown
on 28-29 May 1998 from Fort Sumner, New Mexico, USA. The experiment used the
NMSU-WIZARD/CAPRICE98 balloon-borne magnet spectrometer equipped with a gas
Ring Imaging Cherenkov (RICH) detector, a time-of-flight system, a tracking
device consisting of drift chambers and a superconducting magnet and a
silicon-tungsten calorimeter. The RICH detector was the first ever flown
capable of mass-resolving charge-one particles at energies above 5 GeV.
A total of 31 antiprotons with rigidities between 4 and 50 GV at the
spectrometer were identified with small backgrounds from other particles. The
absolute antiproton energy spectrum was determined in the kinetic energy region
at the top of the atmosphere between 3.2 and 49.1 GeV. We found that the
observed antiproton spectrum and the antiproton-to-proton ratio are consistent
with a pure secondary origin. However, a primary component may not be excluded.Comment: 39 pages, 11 Postscript figures, uses AAS LATEX style; changes in
sections 3.1.1, 3.3, 3.4 and 6, Figure 8 modified, 2 figures added, typos
correcte
Where do we stand with solar neutrino oscillations?
We determine the neutrino parameters for MSW and vacuum oscillations (active
and sterile neutrinos) that are allowed by the separate, and collective,
imposition of the constraints from total event rates in the chlorine, GALLEX,
SAGE, and SuperKamiokande experiments (504 days), the SuperKamiokande electron
energy spectrum, and the SuperKamiokande zenith-angle dependence. The small
mixing angle MSW solution is acceptable at the 7% C.L. (8% for sterile nu's)
and the vacuum solution is acceptable at the 6% C.L. . The best-fit global MSW
solution for active neutrinos is: Delta m^2 = 5 x 10^-6 eV^2, sin^2 (2 theta) =
5.5 x 10^{-3} (and for sterile neutrinos: Delta m^2 = 4 x 10^-6 eV^2, sin^2 (2
theta) = 7 x 10^-3). For vacuum oscillations, the best-fit solution is: Delta
m^2 = 6.5 x 10^-11 eV^2, sin^2 (2 theta) = 0.75 . An arbitrary combination of
undistorted (no oscillations) pp, 7Be, 8B, and CNO neutrino fluxes is
inconsistent with the combined data sets at the 3.5 sigma C.L., independent of
astrophysical considerations. We use improved calculations of solar model
fluxes, neutrino absorption cross sections and energy spectra, and a detailed
evaluation of regeneration effects.Comment: LaTeX file. Added Figure comparing with SuperK spectrum. Predictions
for LENS experiment. Viewgraphs and related information at
http://www.sns.ias.edu/~jn
Sedimentation and Fouling of Optical Surfaces at the ANTARES Site
ANTARES is a project leading towards the construction and deployment of a
neutrino telescope in the deep Mediterranean Sea. The telescope will use an
array of photomultiplier tubes to detect the Cherenkov light emitted by muons
resulting from the interaction with matter of high energy neutrinos. In the
vicinity of the deployment site the ANTARES collaboration has performed a
series of in-situ measurements to study the change in light transmission
through glass surfaces during immersions of several months. The average loss of
light transmission is estimated to be only ~2% at the equator of a glass sphere
one year after deployment. It decreases with increasing zenith angle, and tends
to saturate with time. The transmission loss, therefore, is expected to remain
small for the several year lifetime of the ANTARES detector whose optical
modules are oriented downwards. The measurements were complemented by the
analysis of the ^{210}Pb activity profile in sediment cores and the study of
biofouling on glass plates. Despite a significant sedimentation rate at the
site, in the 0.02 - 0.05 cm.yr^{-1} range, the sediments adhere loosely to the
glass surfaces and can be washed off by water currents. Further, fouling by
deposits of light-absorbing particulates is only significant for surfaces
facing upwards.Comment: 18 pages, 14 figures (pdf), submitted to Astroparticle Physic
The ANTARES Optical Module
The ANTARES collaboration is building a deep sea neutrino telescope in the
Mediterranean Sea. This detector will cover a sensitive area of typically 0.1
km-squared and will be equipped with about 1000 optical modules. Each of these
optical modules consists of a large area photomultiplier and its associated
electronics housed in a pressure resistant glass sphere. The design of the
ANTARES optical module, which is a key element of the detector, has been
finalized following extensive R & D studies and is reviewed here in detail.Comment: 26 pages, 15 figures, to be published in NI
- âŠ