84 research outputs found
Capabilities of the GAMMA-400 gamma-ray telescope to detect gamma-ray bursts from lateral directions
The currently developing space-based gamma-ray telescope GAMMA-400 will
measure the gamma-ray and electrons + positrons fluxes using the main top-down
aperture in the energy range from ~20 MeV to several TeV in the highly elliptic
orbit (without shadowing the telescope by the Earth and outside the radiation
belts) continuously for a long time. The instrument will provide fundamentally
new data on discrete gamma-ray sources, gamma-ray bursts (GRBs), sources and
propagation of Galactic cosmic rays and signatures of dark matter due to its
unique angular and energy resolutions in the wide energy range. The gamma-ray
telescope consists of the anticoincidence system (AC), the converter-tracker
(C), the time-of-flight system (S1 and S2), the position-sensitive and
electromagnetic calorimeters (CC1 and CC2), the top and bottom scintillation
detectors of the calorimeter (S3 and S4) and lateral detectors of the
calorimeter (LD). In this paper, the capabilities of the GAMMA-400 gamma-ray
telescope to measure fluxes of GRBs from lateral directions of CC2 are analyzed
using Monte-Carlo simulations. The analysis is based on second-level trigger
construction using signals from S3, CC2, S4 and LD detectors. For checking the
numerical algorithm the data from space-based GBM and LAT instruments of the
Fermi experiment are used, namely, three long bursts: GRB 080916C, GRB 090902B,
GRB 090926A and one short burst GRB 090510A. The obtained results allow us to
conclude that from lateral directions the GAMMA-400 space-based gamma-ray
telescope will reliably measure the spectra of bright GRBs in the energy range
from ~10 to ~100 MeV with the effective area of about 0.13 m2 (for each of the
four sides of CC2) and total field of view of about 6 sr.Comment: 19 pages, 18 figures, the paper will be submitted to Advances in
Space Researc
Long term time variability of cosmic rays and possible relevance to the development of life on Earth
An analysis is made of the manner in which the cosmic ray intensity at Earth
has varied over its existence and its possible relevance to both the origin and
the evolution of life. Much of the analysis relates to the 'high energy' cosmic
rays () and their variability due to the changing
proximity of the solar system to supernova remnants which are generally
believed to be responsible for most cosmic rays up to PeV energies. It is
pointed out that, on a statistical basis, there will have been considerable
variations in the likely 100 My between the Earth's biosphere reaching
reasonable stability and the onset of very elementary life. Interestingly,
there is the increasingly strong possibility that PeV cosmic rays are
responsible for the initiation of terrestrial lightning strokes and the
possibility arises of considerable increases in the frequency of lightnings and
thereby the formation of some of the complex molecules which are the 'building
blocks of life'. Attention is also given to the well known generation of the
oxides of nitrogen by lightning strokes which are poisonous to animal life but
helpful to plant growth; here, too, the violent swings of cosmic ray
intensities may have had relevance to evolutionary changes. A particular
variant of the cosmic ray acceleration model, put forward by us, predicts an
increase in lightning rate in the past and this has been sought in Korean
historical records. Finally, the time dependence of the overall cosmic ray
intensity, which manifests itself mainly at sub-10 GeV energies, has been
examined. The relevance of cosmic rays to the 'global electrical circuit'
points to the importance of this concept.Comment: 18 pages, 5 figures, accepted by 'Surveys in Geophysics
High-energy gamma-ray studying with GAMMA-400 after Fermi-LAT
Fermi-LAT has made a significant contribution to the study of high-energy gamma-ray diffuse emission and the observation of 3c3000 discrete sources. However, one third of all gamma-ray sources (both galactic and extragalactic) are unidentified, the data on the diffuse gamma-ray emission should be clarified, and signatures of dark matter particles in the high-energy gamma-ray range are not observed up to now. GAMMA-400, currently developing gamma-ray telescope, will have the angular ( 3c0.01\ub0 at 100 GeV) and energy ( 3c1% at 100 GeV) resolutions in the energy range of 10-1000 GeV better than the Fermi-LAT (as well as ground gamma-ray telescopes) by a factor of 5-10 and observe some regions of the Universe (such as Galactic Center, Fermi Bubbles, Crab, Cygnus, etc.) in the highly elliptic orbit (without shading the telescope by the Earth) continuously for a long time. It will permit to identify many discrete sources, to clarify the structure of extended sources, to specify the data on the diffuse emission, and to resolve gamma rays from dark matter particles
The GAMMA-400 gamma-ray telescope for precision gamma-ray emission investigations
The GAMMA-400 gamma-ray telescope with excellent angular and energy resolutions is designed to search for signatures of dark matter in the fluxes of gamma-ray emission and electrons + positrons. Precision investigations of gamma-ray emission from Galactic Center, Crab, Vela, Cygnus, Geminga, and other regions will be performed, as well as diffuse gamma-ray emission, along with measurements of high-energy electron + positron and nuclei fluxes. Furthermore, it will study gamma-ray bursts and gamma-ray emission from the Sun during periods of solar activity. The GAMMA-400 energy range is expected to be from â\u88¼20 MeV up to TeV energies for gamma rays, up to 10 TeV for electrons + positrons, and up to 1015eV for cosmic-ray nuclei. For 100-GeV gamma rays, the GAMMA-400 angular resolution is â\u88¼0.01° and energy resolution is â\u88¼1%; the proton rejection factor is â\u88¼5x105. GAMMA-400 will be installed onboard the Russian space observatory
GAMMA-400 gamma-ray observatory
The GAMMA-400 gamma-ray telescope with excellent angular and energy
resolutions is designed to search for signatures of dark matter in the fluxes
of gamma-ray emission and electrons + positrons. Precision investigations of
gamma-ray emission from Galactic Center, Crab, Vela, Cygnus, Geminga, and other
regions will be performed, as well as diffuse gamma-ray emission, along with
measurements of high-energy electron + positron and nuclei fluxes. Furthermore,
it will study gamma-ray bursts and gamma-ray emission from the Sun during
periods of solar activity. The energy range of GAMMA-400 is expected to be from
~20 MeV up to TeV energies for gamma rays, up to 20 TeV for electrons +
positrons, and up to 10E15 eV for cosmic-ray nuclei. For high-energy gamma rays
with energy from 10 to 100 GeV, the GAMMA-400 angular resolution improves from
0.1{\deg} to ~0.01{\deg} and energy resolution from 3% to ~1%; the proton
rejection factor is ~5x10E5. GAMMA-400 will be installed onboard the Russian
space observatory.Comment: 8 pages, 2 figures, 2 tables, submitted to the proceedings of
ICRC201
Addendum to the CLOUD proposal
This report is the first of two addenda to the CLOUD proposal at CERN (physics/0104048), which aims to test experimentally the existence a link between cosmic rays and cloud formation, and to understand the microphysical mechanism. The document provides further details on the detector design, scientific motivation and experimental programme
CLOUD: an atmospheric research facility at CERN
This report is the second of two addenda to the CLOUD proposal at CERN (physics/0104048), which aims to test experimentally the existence a link between cosmic rays and cloud formation, and to understand the microphysical mechanism. The document places CLOUD in the framework of a CERN facility for atmospheric research, and provides further details on the particle beam requirements
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Energetic particle influence on the Earth's atmosphere
This manuscript gives an up-to-date and comprehensive overview of the effects of energetic particle precipitation (EPP) onto the whole atmosphere, from the lower thermosphere/mesosphere through the stratosphere and troposphere, to the surface. The paper summarizes the different sources and energies of particles, principally
galactic cosmic rays (GCRs), solar energetic particles (SEPs) and energetic electron precipitation (EEP). All the proposed mechanisms by which EPP can affect the atmosphere
are discussed, including chemical changes in the upper atmosphere and lower thermosphere, chemistry-dynamics feedbacks, the global electric circuit and cloud formation. The role of energetic particles in Earth’s atmosphere is a multi-disciplinary problem that requires expertise from a range of scientific backgrounds. To assist with this synergy, summary tables are provided, which are intended to evaluate the level of current knowledge of the effects of energetic particles on processes in the entire atmosphere
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