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Note: This page contains sample records for the topic "int cosmic ray" from the National Library of EnergyBeta (NLEBeta).
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to obtain the most current and comprehensive results.


1

Proc. 26. Int. Cosmic Ray Conf., Salt Lake City (1999), 4, 419--422 Ion injection and acceleration at modified shocks  

E-Print Network [OSTI]

's in producing cosmic rays is the injection process from thermal energies. A self­consistent model has to takeProc. 26. Int. Cosmic Ray Conf., Salt Lake City (1999), 4, 419--422 Ion injection and acceleration incorporates a plasma­physical injection model to investigate the cosmic ray production. 1 Introduction

Gieseler, Udo D. J.

2

24. Cosmic rays 1 24. COSMIC RAYS  

E-Print Network [OSTI]

electrons, protons and helium, as well as carbon, oxygen, iron, and other nuclei synthesized in stars) and the intensity of the cosmic rays with energies below about 10 GeV. In addition, the lower-energy cosmic rays the intensity of any component of the cosmic radiation in the GeV range depends both on the location and time

3

26. Cosmic rays 1 26. COSMIC RAYS  

E-Print Network [OSTI]

electrons, protons and helium, as well as carbon, oxygen, iron, and other nuclei synthesized in stars) and the intensity of the cosmic rays with energies below about 10 GeV. In addition, the lower-energy cosmic rays the intensity of any component of the cosmic radiation in the GeV range depends both on the location and time

4

Cosmic Ray Astronomy  

E-Print Network [OSTI]

Cosmic ray astronomy attempts to identify and study the sources of ultrahigh energy cosmic rays. It is unique in its reliance on charged particles as the information carriers. While no discrete source of ultrahigh energy cosmic rays has been identified so far, a new generation of detectors is acquiring the huge exposure that is needed at the highest energies, where deflection by magnetic fields is minimized and the background from distant sources is eliminated by pion photoproduction. In this paper, we summarize the status of cosmic ray astronomy, describing the detectors and the analysis techniques.

Paul Sommers; Stefan Westerhoff

2008-02-09T23:59:59.000Z

5

Cosmic rays in astrospheres  

E-Print Network [OSTI]

Cosmic rays passing through large astrospheres can be efficiently cooled inside these "cavities" in the interstellar medium. Moreover, the energy spectra of these energetic particles are already modulated in front of the astrospherical bow shocks. We study the cosmic ray flux in and around lambda Cephei as an example for an astrosphere. The large-scale plasma flow is modeled hydrodynamically with radiative cooling. We studied the cosmic ray flux in a stellar wind cavity using a transport model based on stochastic differential equations. The required parameters, most importantly, the elements of the diffusion tensor, are based on the heliospheric parameters. The magnetic field required for the diffusion coefficients is calculated kinematically. We discuss the transport in an astrospheric scenario with varying parameters for the transport coefficients. We show that large stellar wind cavities can act as sinks for the galactic cosmic ray flux and thus can give rise to small-scale anisotropies in the direction to...

Scherer, Klaus; Bomans, Dominik; Ferreira, Stefan; Fichtner, Horst; Kleimann, Jens; Strauss, Dutoit; Weis, Kerstin; Wiengarten, Tobias; Wodzinski, Thomas

2015-01-01T23:59:59.000Z

6

Cosmic Ray Physics  

E-Print Network [OSTI]

Cosmic ray story begins at the beginning of XX century. More then 100 years later, most of the main issues are still open questions, as sources, acceleration mechanism, propagation and composition. There is a continuing fascination with the studies of cosmic radiation mostly from the several contradictions connected to its observation. The radiation has an energy spectrum ranging from $\\sim$ 1 GeV to beyond 10$^{20}$ eV with a flux going from 1 particle per m$^2$ per $\\mu$s to less then 1 particle per km$^2$ per century, and so very different experimental techniques are needed to perform cosmic ray measurements in the different energy intervals. In this contribution the actual experimental status of cosmic ray knowledge will be reviewed.

D'Urso, Domenico

2014-01-01T23:59:59.000Z

7

Cosmic ray research Public lecture  

E-Print Network [OSTI]

energy cosmic rays in Argentina 2 p.m., Wednesday, October 6, 2010 128 Jabara Hall Watkins Visiting powerful, high-energy cosmic rays that periodically bombard Earth. The project includes more than 450

8

Cosmic Ray Telescopes  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Cosmic Ray Muon Detectors Cosmic Ray Muon Detectors Particle Physics Using Nature's Accelerator Somewhere out there is a list of "10 Things a Physics Teacher is Least Likely to Say." If one were to find this list, it would have on it such gems as #7. Let's challenge the PE Dept to a game of rugby and #4. I don't care if you understand the concept, just give me the correct answer to 12 sig figs. Finally, you'd get down to the biggie, the thing physics teachers never say: #1. Let's do a particle physics lab right here at Podunk Corners High! The traditional reasons for this are that everyone knows that particle physics is only done with Vastly Expensive and Complicated Equipment run by casts of thousands of Highly Qualified Scientists and that particle physics is Difficult and Arcane.

9

The Origin of Cosmic Rays  

ScienceCinema (OSTI)

Cosmic Rays reach the Earth from space with energies of up to more than 1020 eV, carrying information on the most powerful particle accelerators that Nature has been able to assemble. Understanding where and how cosmic rays originate has required almost one century of investigations, and, although the last word is not written yet, recent observations and theory seem now to fit together to provide us with a global picture of the origin of cosmic rays of unprecedented clarity. Here we will describe what we learned from recent observations of astrophysical sources (such as supernova remnants and active galaxies) and we will illustrate what these observations tell us about the physics of particle acceleration and transport. We will also discuss the ?end? of the Galactic cosmic ray spectrum, which bridges out attention towards the so called ultra high energy cosmic rays (UHECRs). At ~1020 eV the gyration scale of cosmic rays in cosmic magnetic fields becomes large enough to allow us to point back to their sources, thereby allowing us to perform ?cosmic ray astronomy?, as confirmed by the recent results obtained with the Pierre Auger Observatory. We will discuss the implications of these observations for the understanding of UHECRs, as well as some questions which will likely remain unanswered and will be the target of the next generation of cosmic ray experiments.

Pasquale Blasi

2010-01-08T23:59:59.000Z

10

Cosmic Rays and Experiment CZELTA  

SciTech Connect (OSTI)

This paper gives a review of the physics of cosmic rays with emphasis on the methods of detection and study. A summary is given of the Czech project CZELTA which is part of a multinational program to study cosmic rays with energies above 10{sup 14} eV.

Smolek, Karel; Nyklicek, Michal [Institute of Experimental and Applied Physics, Czech Technical University in Prague, Horska 3a/22, 128 00 Prague 2 (Czech Republic); Kovacikova, Petra [Faculty of Philosophy and Science, Silesian University in Opava, Bezrucovo namesti 13, 746 01 Opava (Czech Republic)

2007-11-26T23:59:59.000Z

11

Cosmic Rays and Global Warming  

E-Print Network [OSTI]

It has been claimed by others that observed temporal correlations of terrestrial cloud cover with `the cosmic ray intensity' are causal. The possibility arises, therefore, of a connection between cosmic rays and Global Warming. If true, the implications would be very great. We have examined this claim to look for evidence to corroborate it. So far we have not found any and so our tentative conclusions are to doubt it. Such correlations as appear are more likely to be due to the small variations in solar irradiance, which, of course, correlate with cosmic rays. We estimate that less than 15% of the 11-year cycle warming variations are due to cosmic rays and less than 2% of the warming over the last 35 years is due to this cause.

T. Sloan; A W Wolfendale

2007-06-28T23:59:59.000Z

12

Cosmic Ray Origins: An Introduction  

E-Print Network [OSTI]

Physicists have pondered the origin of cosmic rays for over a hundred years. However the last few years have seen an upsurge in the observation, progress in the theory and a genuine increase in the importance attached to the topic due to its intimate connection to the indirect detection of evidence for dark matter. The intent of this talk is to set the stage for the meeting by reviewing some of the basic features of the entire cosmic ray spectrum from GeV to ZeV energy and some of the models that have been developed. The connection will also be made to recent developments in understanding general astrophysical particle acceleration in pulsar wind nebulae, relativistic jets and gamma ray bursts. The prospects for future discoveries, which may elucidate the origin of cosmic rays, are bright.

Blandford, Roger; Yuan, Yajie

2014-01-01T23:59:59.000Z

13

Cosmic Rays at the Knee  

E-Print Network [OSTI]

Several kinds of measurements are combined in an attempt to obtain a consistent estimate of the spectrum and composition of the primary cosmic radiation through the knee region. Assuming that the knee is a signal of the high-energy end of a galactic cosmic-ray population, I discuss possible signatures of a transition to an extra-galactic population and how they might be detected.

Thomas K. Gaisser

2006-08-25T23:59:59.000Z

14

Ultra High Energy Cosmic Rays  

Science Journals Connector (OSTI)

We discuss briefly the phenomenon of the Ultra High Energy Cosmic Rays (UHECR) particles of energy approaching and exceeding 1011 GeV. The world experimental statistics contains a small number of events but their existence is a puzzle. Its solution may lead to exciting discoveries in high energy particle astrophysics as well as in particle physics and astronomy.

Todor Stanev

2004-01-01T23:59:59.000Z

15

Ultra High Energy Cosmic Rays  

Science Journals Connector (OSTI)

......tral data at energies above 1 EeV (1018eV...from the AGASA project, are very suggestive...since these low energy cosmic rays have...the outflowing solar wind plasma and...it does on the energy limit set by the solar wind. Since there......

Roger Clay

2003-05-01T23:59:59.000Z

16

Cosmic-ray driven winds  

E-Print Network [OSTI]

The theory of Galactic Winds, driven by the cosmic-ray pressure gradient, is reviewed both on the magnetohydrodynamic and on the kinetic level. In this picture the magnetic field of the Galaxy above the dense gas disk is assumed to have a flux tube geometry, the flux tubes rising locally perpendicular out of the disk to become radially directed at large distances, with the cosmic-ray sources located deep within the Galactic disk. At least above the gas disk, the magnetic fluctuations which resonantly scatter the cosmic rays are selfconsistently excited as Alf{`e}n waves by the escaping cosmic rays. The fluctuation amplitudes remain finite through nonlinear wave dissipation. The spatially increasing speed of the resulting outflow results in a diffusion-convection boundary whose position depends on particle momentum. It replaces the escape boundary of static diffusion models. New effects like overall Galactic mass and angular momentum loss as well as gas heating beyond the disk appear. Also particle re-accelera...

Vlk, Heinrich J

2014-01-01T23:59:59.000Z

17

High-energy Cosmic Rays  

E-Print Network [OSTI]

After a brief review of galactic cosmic rays in the GeV to TeV energy range, we describe some current problems of interest for particles of very high energy. Particularly interesting are two features of the spectrum, the `knee' above $10^{15}$ eV and the `ankle' above $10^{18}$ eV. An important question is whether the highest energy particles are of extra-galactic origin and, if so, at what energy the transition occurs. A theme common to all energy ranges is use of nuclear abundances as a tool for understanding the origin of the cosmic radiation.

Thomas K. Gaisser; Todor Stanev

2005-10-11T23:59:59.000Z

18

Cosmic Rays and Gamma Ray Bursts From Microblazars  

E-Print Network [OSTI]

Highly relativistic jets from merger and accretion induced collapse of compact stellar objects, which may produce the cosmological gamma ray bursts (GRBs), are also very efficient and powerful cosmic ray accelerators. The expected luminosity, energy spectrum and chemical composition of cosmic rays from Galactic GRBs, most of which do not point in our direction, can explain the observed properties of Galactic cosmic rays.

Arnon Dar

1998-09-13T23:59:59.000Z

19

Lunar/Solar effects on Cosmic Rays  

E-Print Network [OSTI]

Lunar/Solar effects on Cosmic Rays By: Sophia Bauer & Jenna Valdez #12;Introduction When cosmic, California." Moon Phase Calendar for Santa Cruz, California. N.p., n.d. Web. 02 Aug. 2012.

California at Santa Cruz, University of

20

Cloud chamber visualization of primary cosmic rays  

SciTech Connect (OSTI)

From 1948 until 1963, cloud chambers were carried to the top of the atmosphere by balloons. From these flights, which were begun by Edward P. Ney at the University of Minnesota, came the following results: discovery of heavy cosmic ray nuclei, development of scintillation and cherenkov detectors, discovery of cosmic ray electrons, and studies of solar proton events. The history of that era is illustrated here by cloud chamber photographs of primary cosmic rays.

Earl, James A. [Department of Astronomy, University of Maryland, College Park MD (United States)

2013-02-07T23:59:59.000Z

Note: This page contains sample records for the topic "int cosmic ray" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

High-energy cosmic ray interactions  

SciTech Connect (OSTI)

Research into hadronic interactions and high-energy cosmic rays are closely related. On one hand--due to the indirect observation of cosmic rays through air showers--the understanding of hadronic multiparticle production is needed for deriving the flux and composition of cosmic rays at high energy. On the other hand the highest energy particles from the universe allow us to study the characteristics of hadronic interactions at energies far beyond the reach of terrestrial accelerators. This is the summary of three introductory lectures on our current understanding of hadronic interactions of cosmic rays.

Engel, Ralph [Forschungszentrum Karlsruhe, P.O. Box 3640, 76021 Karlsruhe (Germany); Orellana, Mariana [Instituto Argentino de Radioastronomia (IAR), CCT La Plata (CONICET), C.C.5, 1894 Villa Elisa, Buenos Aires (Argentina); Facultad de Ciencias Astronomicas y Geofisicas, Universidad Nacional de La Plata, Paseo del Bosque, 1900 La Plata (Argentina); Reynoso, Matias M. [Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Funes 3350, (7600) Mar del Plata (Argentina); Instituto de Investigaciones Fisicas de Mar del Plata, (UNMdP-CONICET) (Argentina); Vila, Gabriela S. [Instituto Argentino de Radioastronomia (IAR), CCT La Plata (CONICET), C.C.5, 1894 Villa Elisa, Buenos Aires (Argentina)

2009-04-30T23:59:59.000Z

22

Cosmic Ray Physics with ACORDE at LHC  

E-Print Network [OSTI]

The use of large underground high-energy physics experiments, for comic ray studies, have been used, in the past, at CERN, in order to measure, precisely, the inclusive cosmic ray flux in the energy range from 2x10^10 - 2x10^12 eV. ACORDE, ALICE Cosmic Rays DEtector, will act as Level 0 cosmic ray trigger and, together with other ALICE apparatus, will provide precise information on cosmic rays with primary energies around 10^15 - 10^17 eV. This paper reviews the main detector features, the present status, commissioning and integration with other apparatus. Finally, we discuss the ACORDE-ALICE cosmic ray physics program.

C. Pagliarone; A. Fernandez-Tellez

2007-09-19T23:59:59.000Z

23

Terrestrial Effects of High Energy Cosmic Rays  

E-Print Network [OSTI]

On geological timescales, the Earth is likely to be exposed to higher than the usual flux of high energy cosmic rays (HECRs) from astrophysical sources such as nearby supernovae, gamma ray bursts or by galactic shocks. ...

Atri, Dimitra

2011-04-26T23:59:59.000Z

24

Probing Fukushima with cosmic rays should help speed cleanup...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Probing Fukushima with cosmic rays Probing Fukushima with cosmic rays should help speed cleanup of damaged plant The initiative could reduce the time required to clean up the...

25

A theory of Cosmic Rays  

E-Print Network [OSTI]

We present a theory of non-solar cosmic rays (CRs) in which the bulk of their observed flux is due to a single type of CR source at all energies. The total luminosity of the Galaxy, the broken power-law spectra with their observed slopes, the position of the `knee(s)' and `ankle', and the CR composition and its variation with energy are all predicted in terms of very simple and completely `standard' physics. The source of CRs is extremely `economical': it has only one parameter to be fitted to the ensemble of all of the mentioned data. All other inputs are `priors', that is, theoretical or observational items of information independent of the properties of the source of CRs, and chosen to lie in their pre-established ranges. The theory is part of a `unified view of high-energy astrophysics' --based on the `Cannonball' model of the relativistic ejecta of accreting black holes and neutron stars. The model has been extremely successful in predicting all the novel properties of Gamma Ray Bursts recently observed with help of the Swift satellite. If correct, this model is only lacking a satisfactory theoretical understanding of the `cannon' that emits the cannonballs in catastrophic processes of accretion.

Arnon Dar; Alvaro De Rujula

2006-06-19T23:59:59.000Z

26

The beginning of cosmic ray astronomy  

E-Print Network [OSTI]

We discuss the anisotropic arrival directions of the ultra high energy cosmic rays detected by Auger which I consider one of the biggest discoverie in astrophysics during the last year.

Todor Stanev

2008-08-08T23:59:59.000Z

27

Cosmic-ray muons at ultrahigh energies  

Science Journals Connector (OSTI)

Fluxes of cosmic-ray muons were estimated over the energy range extending up to 1010 GeV. Data on the production of pions; kaons; ?, ??, ?, ?, and ? mesons; charmed particles; and J/?...mesons from accelerator ex...

L. V. Volkova

2011-02-01T23:59:59.000Z

28

Gamma Ray Bursts from Ordinary Cosmic Strings  

E-Print Network [OSTI]

We give an upper estimate for the number of gamma ray bursts from ordinary (non-superconducting) cosmic strings expected to be observed at terrestrial detectors. Assuming that cusp annihilation is the mechanism responsible for the bursts we consider strings arising at a GUT phase transition and compare our estimate with the recent BATSE results. Further we give a lower limit for the effective area of future detectors designed to detect the cosmic string induced flux of gamma ray bursts.

R. H. Brandenberger; A. T. Sornborger; M. Trodden

1993-02-12T23:59:59.000Z

29

Influence of Cosmic Rays on Earth's Climate  

Science Journals Connector (OSTI)

During the last solar cycle Earth's cloud cover underwent a modulation more closely in phase with the galactic cosmic ray flux than with other solar activity parameters. Further it is found that Earth's temperature follows more closely decade variations in galactic cosmic ray flux and solar cycle length, than other solar activity parameters. The main conclusion is that the average state of the heliosphere affects Earth's climate.

Henrik Svensmark

1998-11-30T23:59:59.000Z

30

A theory of Cosmic Rays  

E-Print Network [OSTI]

We present a theory of non-solar cosmic rays (CRs) based on a single type of CR source at all energies. The total luminosity of the Galaxy, the broken power-law spectra with their observed slopes, the position of the `knee(s)' and `ankle', and the CR composition and its variation with energy are all predicted in terms of very simple and completely `standard' physics. The source of CRs is extremely `economical': it has only one parameter to be fitted to the ensemble of all of the mentioned data. All other inputs are `priors', that is, theoretical or observational items of information independent of the properties of the source of CRs, and chosen to lie in their pre-established ranges. The theory is part of a `unified view of high-energy astrophysics' --based on the `Cannonball' model of the relativistic ejecta of accreting black holes and neutron stars. If correct, this model is only lacking a satisfactory theoretical understanding of the `cannon' that emits the cannonballs in catastrophic processes of accreti...

Dar, Arnon; Dar, Arnon; Rjula, Alvaro De

2008-01-01T23:59:59.000Z

31

Jupiter as a Giant Cosmic Ray Detector  

E-Print Network [OSTI]

We explore the feasibility of using the atmosphere of Jupiter to detect Ultra-High-Energy Cosmic Rays (UHECR's). The large surface area of Jupiter allows us to probe cosmic rays of higher energies than previously accessible. Cosmic ray extensive air showers in Jupiter's atmosphere could in principle be detected by the Large Area Telescope (LAT) on the Fermi observatory. In order to be observed, these air showers would need to be oriented toward the Earth, and would need to occur sufficiently high in the atmosphere that the gamma rays can penetrate. We demonstrate that, under these assumptions, Jupiter provides an effective cosmic ray "detector" area of $3.3 \\times 10^7$ km$^2$. We predict that Fermi-LAT should be able to detect events of energy $>10^{21}$ eV with fluence $10^{-7}$ erg cm$^{-2}$ at a rate of about one per month. The observed number of air showers may provide an indirect measure of the flux of cosmic rays $\\gtrsim 10^{20}$ eV. Extensive air showers also produce a synchrotron signature that may ...

Rimmer, Paul B; Helling, Christiane

2014-01-01T23:59:59.000Z

32

Cosmic rays and tests of fundamental principles  

E-Print Network [OSTI]

It is now widely acknowledged that cosmic rays experiments can test possible new physics directly generated at the Planck scale or at some other fundamental scale. By studying particle properties at energies far beyond the reach of any man-made accelerator, they can yield unique checks of basic principles. A well-known example is provided by possible tests of special relativity at the highest cosmic-ray energies. But other essential ingredients of standard theories can in principle be tested: quantum mechanics, uncertainty principle, energy and momentum conservation, effective space-time dimensions, hamiltonian and lagrangian formalisms, postulates of cosmology, vacuum dynamics and particle propagation, quark and gluon confinement, elementariness of particles... Standard particle physics or string-like patterns may have a composite origin able to manifest itself through specific cosmic-ray signatures. Ultra-high energy cosmic rays, but also cosmic rays at lower energies, are probes of both "conventional" and new Physics. Status, prospects, new ideas, and open questions in the field are discussed. The Post Scriptum shows that several basic features of modern cosmology naturally appear in a SU(2) spinorial description of space-time without any need for matter, relativity or standard gravitation. New possible effects related to the spinorial space-time structure can also be foreseen. Similarly, the existence of spin-1/2 particles can be naturally related to physics beyond Planck scale and to a possible pre-Big Bang era.

Luis Gonzalez-Mestres

2010-11-22T23:59:59.000Z

33

Supernova Remnants, Cosmic Rays, and GLAST  

SciTech Connect (OSTI)

The shock waves of supernova remnants (SNRs) are the traditional sources of Galactic cosmic rays, at least up to about 3000 TeV (the 'knee' energy in the cosmic-ray spectrum). In the last decade or so, X-ray observations have confirmed in a few SNRs the presence of synchrotron-X-ray-emitting electrons with energies of order 100 TeV. TeV photons from SNRs have been observed with ground-based air Cerenkov telescopes as well, but it is still unclear whether they are due to hadronic processes (inelastic p-p scattering of cosmic-ray protons from thermal gas, with secondary neutral pions decaying to gamma rays), or to leptonic processes (inverse-Compton upscattering of cosmic microwave background photons, or bremsstrahlung). The spatial structure of synchrotron X-rays as observed with the Chandra X-ray Observatory suggests the remarkable possibility that magnetic fields are amplified by orders of magnitude in strong shock waves. The electron spectra inferred from X-rays reach 100 TeV, but at that energy are cutting off steeply, well below the 'knee' energy. Are the cutoff processes due only to radiative losses so that ion spectra might continue unsteepened? Can we confirm the presence of energetic ions in SNRs at all? Are typical SNRs capable of supplying the pool of Galactic cosmic rays? Is strong magnetic-field amplification a property of strong astrophysical shocks in general? These major questions require the next generation of observational tools. I shall outline the theoretical and observational framework of particle acceleration to high energies in SNRs, and shall describe how GLAST will advance this field.

Reynolds, Steve (North Carolina State University) [North Carolina State University

2006-02-13T23:59:59.000Z

34

Anomalous isotopic composition of cosmic rays  

SciTech Connect (OSTI)

Recent measurements of nonsolar isotopic patterns for the elements neon and (perhaps) magnesium in cosmic rays are interpreted within current models of stellar nucleosynthesis. One possible explanation is that the stars currently responsible for cosmic-ray synthesis in the Galaxy are typically super-metal-rich by a factor of two to three. Other possibilities include the selective acceleration of certain zones or masses of supernovas or the enhancement of /sup 22/Ne in the interstellar medium by mass loss from red giant stars and planetary nebulas. Measurements of critical isotopic ratios are suggested to aid in distinguishing among the various possibilities. Some of these explanations place significant constraints on the fraction of cosmic ray nuclei that must be fresh supernova debris and the masses of the supernovas involved. 1 figure, 3 tables.

Woosley, S.E.; Weaver, T.A.

1980-06-20T23:59:59.000Z

35

High energy cosmic rays, gamma rays and neutrinos from AGN  

E-Print Network [OSTI]

The author reviews a model for the emission of high energy cosmic rays, gamma-rays and neutrinos from AGN (Active Galactic Nuclei) that he has proposed since 1985. Further discussion of the knee energy phenomenon of the cosmic ray energy spectrum requires the existence of a heavy particle with mass in the knee energy range. A possible method of detecting such a particle in the Pierre Auger Project is suggested. Also presented is a relation between the spectra of neutrinos and gamma-rays emitted from AGN. This relation can be tested by high energy neutrino detectors such as ICECUBE, the Mediterranean Sea Detector and possibly by the Pierre Auger Project.

Yukio Tomozawa

2008-02-03T23:59:59.000Z

36

Collection: High-Energy Cosmic Ray Event Data from the Pierre...  

Office of Scientific and Technical Information (OSTI)

High-Energy Cosmic Ray Event Data from the Pierre Auger Cosmic Ray Observatory Citation Details Title: High-Energy Cosmic Ray Event Data from the Pierre Auger Cosmic Ray...

37

Energy spectrum of cosmic-ray muons  

Science Journals Connector (OSTI)

The energy spectrum of cosmic-ray muons at sea-level is calculated by the ... in good agreement with the observed data of muons with the zenith angles of 0 and ... the scaling model is valid up to the muon energy

H. Komori; K. Mitsui

38

Accelerator Data for Cosmic Ray Physics  

E-Print Network [OSTI]

I present selected examples of accelerator data, mainly from hadron colliders, that are relevant for understanding cosmic ray showers. I focus on the forward region, $x_{Feynman} > 0.05$, where high energy data are scarce, since the emphasis in collider physics became high-$p_T$ phenomena.

M. G. Albrow

2010-09-21T23:59:59.000Z

39

Catching the highest energy cosmic rays  

Science Journals Connector (OSTI)

......interest in very-high-energy cosmic rays, which I define arbitrarily as those of energies above 3 1018 eV, the devices...Pierre Auger Observatory in Argentina - and what has been deduced...the measurements of the energy spectrum and arrival directions......

Alan A Watson

2009-04-01T23:59:59.000Z

40

Student Projects in Cosmic Ray Detection  

Science Journals Connector (OSTI)

The Alberta Large?area Time?coincidence Array (ALTA) study has been in existence for about 10 years under the direction of Jim Pinfold of the Centre for Particle Physics at the University of Alberta.1 The purpose of the ALTA project is to involve Alberta high schools and primarily their physics classes to assist in the detection of the presence of cosmic ray bursts in different Alberta locations. These cosmic rays involve highspeed elementary particles many from far outside our solar system and even from outside our galaxy. These particles collide with the particles in our atmosphere break up these molecules into rather exotic elementary particles which often reach the surface of the Earth and can be detected by fairly simple equipment. One of the objectives of ALTA is to determine the nature of some of the most energetic cosmic ray particles whose origin is still not known. Recently 2the Pierre Auger Collaboration has confirmed that the highest energy cosmic rays appear to be coming from nearby galaxies. The mechanism for their production is still not well understood.

W. Brouwer; J. Pinfold; R. Soluk; B. McDonough; V. Pasek; Zheng Bao?shan

2009-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "int cosmic ray" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Gamma-Ray Bursts, Ultra High Energy Cosmic Rays, and Cosmic Gamma-Ray Background  

E-Print Network [OSTI]

We argue that gamma-ray bursts (GRBs) may be the origin of the cosmic gamma-ray background radiation observed in GeV range. It has theoretically been discussed that protons may carry a much larger amount of energy than electrons in GRBs, and this large energy can be radiated in TeV range by synchrotron radiation of ultra-high-energy protons (\\sim 10^{20} eV). The possible detection of GRBs above 10 TeV suggested by the Tibet and HEGRA groups also supports this idea. If this is the case, most of TeV gamma-rays from GRBs are absorbed in intergalactic fields and eventually form GeV gamma-ray background, whose flux is in good agreement with the recent observation.

Tomonori Totani

1998-10-14T23:59:59.000Z

42

The Pierre Auger Cosmic Ray Observatory  

E-Print Network [OSTI]

The Pierre Auger Observatory, located on a vast, high plain in western Argentina, is the world's largest cosmic ray observatory. The objectives of the Observatory are to probe the origin and characteristics of cosmic rays above $10^{17}$ eV and to study the interactions of these, the most energetic particles observed in nature. The Auger design features an array of 1660 water-Cherenkov particle detector stations spread over 3000 km$^2$ overlooked by 24 air fluorescence telescopes. In addition, three high elevation fluorescence telescopes overlook a 23.5 km$^2$, 61 detector infill array. The Observatory has been in successful operation since completion in 2008 and has recorded data from an exposure exceeding 40,000 km$^2$ sr yr. This paper describes the design and performance of the detectors, related subsystems and infrastructure that make up the Auger Observatory.

,

2015-01-01T23:59:59.000Z

43

Phenomenology of cosmic ray air showers  

E-Print Network [OSTI]

The properties of cosmic rays with energies above 1PeV have to be deduced from the spacetime structure and particle content of the air showers which they initiate. In this review, a summary of the phenomenology of these giant air showers is presented. We describe the hadronic interaction models used to extrapolate results from collider data to ultra high energies, an also the main electromagnetic processes that govern the longitudinal shower evolution as well as the lateral spread of particles.

M. T. Dova

2005-05-30T23:59:59.000Z

44

Reference Radiation for Cosmic Rays in RBE Research  

E-Print Network [OSTI]

When astronauts travel in space, they are exposed to high energy cosmic radiations. The cosmic ray spectrum contains very high energy particles, generally up to several GeV per nucleon. Currently NASA is funding research on the effects...

Feng, Shaoyong

2011-10-21T23:59:59.000Z

45

Solar panels as cosmic-ray detectors  

E-Print Network [OSTI]

Due to fundamental limitations of accelerators, only cosmic rays can give access to centre-of- mass energies more than one order of magnitude above those reached at the LHC. In fact, extreme energy cosmic rays (1018 eV - 1020 eV) are the only possibility to explore the 100 TeV energy scale in the years to come. This leap by one order of magnitude gives a unique way to open new horizons: new families of particles, new physics scales, in-depth investigations of the Lorentz symmetries. However, the flux of cosmic rays decreases rapidly, being less than one particle per square kilometer per year above 1019 eV: one needs to sample large surfaces. A way to develop large-effective area, low cost, detectors, is to build a solar panel-based device which can be used in parallel for power generation and Cherenkov light detection. Using solar panels for Cherenkov light detection would combine power generation and a non-standard detection device.

Stella, Carlo; Assis, Pedro; Brogueira, Pedro; Santo, Catarina Espirito; Goncalves, Patricia; Pimenta, Mario; De Angelis, Alessandro

2014-01-01T23:59:59.000Z

46

Invariance Violation Extends the Cosmic Ray Horizon?  

E-Print Network [OSTI]

We postulate in the present paper that the energy-momentum relation is modified for very high energy particles to violate Lorentz invariance and the speed of photon is changed from the light velocity c. The violation effect is amplified, in a sensitive way to detection, through the modified kinematical constraints on the conservation of energy and momentum, in the absorption process of gamma-rays colliding against photons of longer wavelengths and converting into an electron-positron pair. For gamma-rays of energies higher than 10 TeV, the minimum energy of the soft photons for the reaction and then the absorption mean free path of gamma-rays are altered by orders of magnitude from the ones conventionally estimated. Consideration is similarly applied to high energy cosmic ray protons. The consequences may require the standard assumptions on the maximum distance that very high energy radiation can travel from to be revised.

Kifune, T

1999-01-01T23:59:59.000Z

47

Invariance Violation Extends the Cosmic Ray Horizon ?  

E-Print Network [OSTI]

We postulate in the present paper that the energy-momentum relation is modified for very high energy particles to violate Lorentz invariance and the speed of photon is changed from the light velocity c. The violation effect is amplified, in a sensitive way to detection, through the modified kinematical constraints on the conservation of energy and momentum, in the absorption process of gamma-rays colliding against photons of longer wavelengths and converting into an electron-positron pair. For gamma-rays of energies higher than 10 TeV, the minimum energy of the soft photons for the reaction and then the absorption mean free path of gamma-rays are altered by orders of magnitude from the ones conventionally estimated. Consideration is similarly applied to high energy cosmic ray protons. The consequences may require the standard assumptions on the maximum distance that very high energy radiation can travel from to be revised.

T. Kifune

1999-04-13T23:59:59.000Z

48

E-Print Network 3.0 - assumed cosmic ray-modulated Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Morphology of Anomalous Cosmic Rays in the Outer Heliosphere Summary: ray transport equation describes the physics of cosmic ray modulation in the heliosphere... in this equation...

49

On The Origin of Very High Energy Cosmic Rays  

E-Print Network [OSTI]

We discuss the most recent developments in our understanding of the acceleration and propagation of cosmic rays up to the highest energies. In particular we specialize our discussion to three issues: 1) developments in the theory of particle acceleration at shock waves; 2) the transition from galactic to extragalactic cosmic rays; 3) implications of up-to-date observations for the origin of ultra high energy cosmic rays (UHECRs).

Pasquale Blasi

2005-11-08T23:59:59.000Z

50

The origin of ultra high energy cosmic rays  

E-Print Network [OSTI]

We briefly discuss some open problems and recent developments in the investigation of the origin and propagation of ultra high energy cosmic rays (UHECRs).

Pasquale Blasi

2005-12-16T23:59:59.000Z

51

SHIELDING ASTRONAUTS FROM COSMIC RAYS E. N. Parker  

E-Print Network [OSTI]

enshrouded mass of Earth is subject to a continuing low dose rate of galactic cosmic radiation. Exposure years. The best available estimates of the accumulated cosmic radiation damage to the astronauts predict of the ongoing radiation damage by the cosmic rays. Unfortunately there is very little information available

Shepherd, Simon

52

Gravity, Cosmic Rays and the LHC  

E-Print Network [OSTI]

The high energy proton beams expected when the Large Hadron Collider (LHC) comes online should provide a pass/fail test for a gravity-related explanation of ultrahigh energy cosmic rays. The model predicts that particles have two kinds energies, equal for null gravitational potentials and, in the potential at the Earth, differing significantly above one TeV. If correct, a 7 TeV trajectory energy proton at the LHC would deliver a 23.5 TeV particle state energy in a collision.

Richard Shurtleff

2008-01-20T23:59:59.000Z

53

Cosmic Rays on the Pacific Ocean  

Science Journals Connector (OSTI)

Records of cosmic-ray intensity obtained on the R. M. S. Aorangi during 12 voyages between Vancouver, Canada and Sydney, Australia, from March 17, 1936, to January 18, 1937, using a Carnegie model C cosmic-ray meter, are described and discussed. Typical records exhibiting the latitude effect are shown. A summary of the data taken at sea is given in the form of graphs, in which each datum point represents the average of 6 hours readings with a probable statistical error of 0.13 percent. Any variations due to a possible temperature coefficient of the instrument are negligible. The observed minimum of cosmic-ray intensity near the equator averages 10.3 percent less than the intensity at Vancouver, in satisfactory agreement, considering the difference in expermental conditions, with earlier measurements. The critical latitudes above which changes in intensity are less rapid, are found to be somewhat lower, 38.4N and 34.2S, than previously reported, and beyond these latitudes the intensity is found to continue to increase with latitude. At the higher latitudes is observed a variation, which appears to be seasonal, with the maximum in the cold months in both hemispheres. This variation is closely correlated with the atmospheric temperature. It is hence ascribed to changes in some atmospheric barrier of unknown nature, such as perhaps an atmospheric potential gradient, of whose strength the temperature of the atmosphere is an approximate but not exact index. Changes in this atmospheric barrier have been approximately allowed for by determining the external temperature coefficient and correcting the observations accordingly (this external temperature coefficient is comparable with that reported by Hess and his collaborators). The latitude effect curves as thus corrected should show the effect of the earth's magnetic field alone. They are now nearly flat beyond the critical latitudes and show a magnetic latitude effect of about 7.2 percent. This implies that a latitude effect of about 3.1 percent owes its origin to the atmospheric barrier. Seasonal variations in the corrected latitude effect curve are almost eliminated. Geomagnetic analysis of the energy distribution of the rays indicates a prominent component with a sharp energy threshold of about 7.5109 ev, and a component so weak as to be questionable, whose energy threshold is not greater than 2.5109 ev. It is not found possible to explain the 7.5109 ev threshold in terms of atmospheric absorption as has previously been supposed. Two alternative interpretations are suggested. The difference in cosmic-ray intensity between the northern and southern hemispheres under comparable conditions, as calculated from these data in various ways, appears to be no larger than the probable error of about 0.1 percent. This result is in conflict with the prediction by Compton and Getting of an excess in the north of about 0.5 percent, due to the motion of the earth with the rotation of the galaxy, but is not inconsistent with the small diurnal variation that has been found to follow sidereal time, if it is supposed that the cosmic rays acquire a part of the galactic motion.

A. H. Compton and R. N. Turner

1937-10-15T23:59:59.000Z

54

29th International Cosmic Ray Conference Pune (2005) 00, 101106 First Estimate of the Primary Cosmic Ray Energy Spectrum  

E-Print Network [OSTI]

Cosmic Ray Energy Spectrum above 3 EeV from the Pierre Auger Observatory The Pierre Auger Collaboration forerunner experiments. A measurement of the cosmic ray energy spectrum in the southern sky is reported here in Argentina now covers an area of approx- imately 1500 km2 . On good-weather nights, air fluorescence

55

28th International Cosmic Ray Conference 4065 The Cosmic Ray Shadows of the Moon and the Sun De-  

E-Print Network [OSTI]

28th International Cosmic Ray Conference 4065 The Cosmic Ray Shadows of the Moon and the Sun De of the data shows that the shadows of the sun and moon have each been detected with high significances of the sun is significantly weaker than that of the moon. As expected, the measured positions of the deficits

California at Santa Cruz, University of

56

The `excess' of primary cosmic ray electrons  

E-Print Network [OSTI]

With the accurate cosmic ray (CR) electron and positron spectra (denoted as $\\Phi_{\\rm e^{-}}$ and $\\Phi_{\\rm e^{+}}$, respectively) measured by AMS-02 collaboration, the difference between the electron and positron fluxes (i.e., $\\Delta \\Phi=\\Phi_{\\rm e^{-}}-\\Phi_{\\rm e^{+}}$), dominated by the propagated primary electrons, can be reliably inferred. In the standard model, the spectrum of propagated primary CR electrons at energies $\\geq 30$ GeV softens with the increase of energy. The absence of any evidence for such a continuous spectral softening in $\\Delta \\Phi$ strongly suggests a significant `excess' of primary CR electrons and at energies of $100-400$ GeV the identified excess component has a flux comparable to that of the observed positron excess. Middle-age but `nearby' supernova remnants (e.g., Monogem and Geminga) are favored sources for such an excess.

Li, Xiang; Lu, Bo-Qiang; Dong, Tie-Kuang; Fan, Yi-Zhong; Feng, Lei; Liu, Si-Ming; Chang, Jin

2014-01-01T23:59:59.000Z

57

Pulsar Wind Nebulae and Cosmic Rays: A Bedtime Story  

E-Print Network [OSTI]

The role pulsar wind nebulae play in producing our locally observed cosmic ray spectrum remains murky, yet intriguing. Pulsar wind nebulae are born and evolve in conjunction with SNRs, which are favored sites of Galactic cosmic ray acceleration. As a result they frequently complicate interpretation of the gamma-ray emission seen from SNRs. However, pulsar wind nebulae may also contribute directly to the local cosmic ray spectrum, particularly the leptonic component. This paper reviews the current thinking on pulsar wind nebulae and their connection to cosmic ray production from an observational perspective. It also considers how both future technologies and new ways of analyzing existing data can help us to better address the relevant theoretical questions. A number of key points will be illustrated with recent results from the VHE (E > 100 GeV) gamma-ray observatory VERITAS.

,

2014-01-01T23:59:59.000Z

58

Solar Variability, Cosmic Rays and Climate: What's up? The topic of possible relations between solar and cosmic  

E-Print Network [OSTI]

Preface Solar Variability, Cosmic Rays and Climate: What's up? The topic of possible relations between solar and cosmic ray variability on one hand, and Earth's climate on the other hand, is quite in Space Research topical issue on Solar Variability, Cosmic Rays and Climate presents a collection

Usoskin, Ilya G.

59

Gamma ray bursts and extreme energy cosmic rays  

Science Journals Connector (OSTI)

Extreme Energy Cosmic Ray particles (EECR) with E>10 20 ?eV arriving on Earth with very low flux (?1 particle/Km2-1000yr) require for their investigation very large detecting areas exceeding values of 1000 km2?sr. Projects with these dimensions are now being proposed: Ground Arrays (Auger with 23500? km 2 ?sr ) or exploiting the Earth Atmosphere as seen from space (AIR WATCH and OWL with effective area reaching 1 million km2?sr). In this last case by using as a target the 10 13 tons of air viewed also the high energy neutrino flux can be investigated conveniently. Gamma Rays Bursts are suggested as a possible source for EECR and the associated High Energy neutrino flux.

Livio Scarsi

1998-01-01T23:59:59.000Z

60

Are extragalactic gamma ray bursts the source of the highest energy cosmic rays?  

E-Print Network [OSTI]

Recent observations with the large air shower arrays of ultra high energy cosmic rays (UHECR) and recent measurements/estimates of the redshifts of gamma ray bursts (GRBs) seem to rule out extragalactic GRBs as the source of the cosmic rays that are observed near Earth, including those with the highest energies.

Arnon Dar

1999-01-03T23:59:59.000Z

Note: This page contains sample records for the topic "int cosmic ray" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

The cosmic ray muon energy spectum via ?erenkov radiation  

E-Print Network [OSTI]

In this thesis, I designed and constructed a basic Cerenkov detector to measure the energy spectrum of cosmic ray muons for use in the graduate experimental physics courses, 8.811/2. The apparatus consists of a light-tight ...

Quintero, Eric Antonio

2010-01-01T23:59:59.000Z

62

Muons of very and ultra-high energy cosmic rays  

Science Journals Connector (OSTI)

In many cosmic rays experiments at very and ultra-high energies, an excess of muons (including those of very high energy, >100 TeV) is observed that cannot ... compositions, and especially the observed excesses o...

A. G. Bogdanov; R. P. Kokoulin

2013-11-01T23:59:59.000Z

63

Cosmic Ray Muons Timing in the ATLAS Detector  

Science Journals Connector (OSTI)

In this talk I discuss the use of calorimeter timing both for detector commissioning and in searches for new physics. In particular I present real and simulated cosmic ray muons data (2007) results for the ATLAS Tile Calorimeter system. The analysis shows that several detector errors such as imperfect calibrations can be uncovered. I also demonstrate the use of ATLAS Tile Calorimeters excellent timing resolution in suppressing cosmic ray fake missing transverse energy (E T ) in searches for supersymmetry.

Bernhard Meirose; ATLAS Tile Calorimeter System

2009-01-01T23:59:59.000Z

64

A New Measurement of the Cosmic X-ray Background  

SciTech Connect (OSTI)

I present a new analytical description of the cosmic X-ray background (CXRB) spectrum in the 1.5-200 keV energy band, obtained by combining the new measurement performed by the Swift X-ray telescope (XRT) with the recently published Swift burst alert telescope (BAT) measurement. A study of the cosmic variance in the XRT band (1.5-7 keV) is also presented. I find that the expected cosmic variance (expected from LogN-LogS) scales as {omega}{sup -0.3}(where {omega} is the surveyed area) in very good agreement with XRT data.

Moretti, A. [INAF-Osservatorio Astronomico di Brera v. E. Bianchi 46 23807 Merate (Italy)

2009-05-11T23:59:59.000Z

65

A Quantum Phase Transition in the Cosmic Ray Energy Distribution  

E-Print Network [OSTI]

We here argue that the "knee" of the cosmic ray energy distribution at $E_c \\sim 1$ PeV represents a second order phase transition of cosmic proportions. The discontinuity of the heat capacity per cosmic ray particle is given by $\\Delta c=0.450196\\ k_B$. However the idea of a deeper critical point singularity cannot be ruled out by present accuracy in neither theory nor experiment. The quantum phase transition consists of cosmic rays dominated by bosons for the low temperature phase E E_c$. The low temperature phase arises from those nuclei described by the usual and conventional collective boson models of nuclear physics. The high temperature phase is dominated by protons. The transition energy $E_c$ may be estimated in terms of the photo-disintegration of nuclei.

Widom, A; Srivastava, Y

2015-01-01T23:59:59.000Z

66

Propagation of Cosmic Rays: Nuclear Physics in Cosmic-Ray Studies  

SciTech Connect (OSTI)

The nuclei fraction in cosmic rays (CR) far exceeds the fraction of other CR species, such as antiprotons, electrons, and positrons. Thus the majority of information obtained from CR studies is based on interpretation of isotopic abundances using CR propagation models where the nuclear data and isotopic production cross sections in p- and {alpha}-induced reactions are the key elements. This paper presents an introduction to the astrophysics of CR and diffuse {gamma}-rays and discusses some of the puzzles that have emerged recently due to more precise data and improved propagation models. Merging with cosmology and particle physics, astrophysics of CR has become a very dynamic field with a large potential of breakthrough and discoveries in the near future. Exploiting the data collected by the CR experiments to the fullest requires accurate nuclear cross sections.

Moskalenko, Igor V. [NASA/Goddard Space Flight Center, Code 661, Greenbelt, MD 20771 (United States); Joint Center for Astrophysics/University of Maryland, Baltimore County, Baltimore, MD 21250 (United States); Strong, Andrew W. [Max-Planck-Institut fuer extraterrestrische Physik, Postfach 1603, D-85740 Garching (Germany); Mashnik, Stepan G. [Los Alamos National Laboratory, Los Alamos, NM 87544 (United States)

2005-05-24T23:59:59.000Z

67

Feedback Heating by Cosmic Rays in Clusters of Galaxies  

E-Print Network [OSTI]

Recent observations show that the cooling flows in the central regions of galaxy clusters are highly suppressed. Observed AGN-induced cavities/bubbles are a leading candidate for suppressing cooling, usually via some form of mechanical heating. At the same time, observed X-ray cavities and synchrotron emission point toward a significant non-thermal particle population. Previous studies have focused on the dynamical effects of cosmic-ray pressure support, but none have built successful models in which cosmic-ray heating is significant. Here we investigate a new model of AGN heating, in which the intracluster medium is efficiently heated by cosmic-rays, which are injected into the ICM through diffusion or the shredding of the bubbles by Rayleigh-Taylor or Kelvin-Helmholtz instabilities. We include thermal conduction as well. Using numerical simulations, we show that the cooling catastrophe is efficiently suppressed. The cluster quickly relaxes to a quasi-equilibrium state with a highly reduced accretion rate and temperature and density profiles which match observations. Unlike the conduction-only case, no fine-tuning of the Spitzer conduction suppression factor f is needed. The cosmic ray pressure, P_c/P_g heating is a very attractive alternative to mechanical heating, and may become particularly compelling if GLAST detects the gamma-ray signature of cosmic-rays in clusters.

Fulai Guo; S. Peng OH

2007-06-09T23:59:59.000Z

68

Astrophysical explosions: from solar flares to cosmic gamma-ray bursts  

Science Journals Connector (OSTI)

...from solar flares to cosmic gamma-ray bursts J. Craig Wheeler * * wheel...collapse supernovae and cosmic gamma-ray bursts, each representing a different...black holes|supernovae|gamma-ray bursts|deflagration|detonation...

2012-01-01T23:59:59.000Z

69

Can Ultrahigh Energy Cosmic Rays Come from Gamma-Ray Bursts? II: Cosmic Rays Below the Ankle and Galactic GRB  

E-Print Network [OSTI]

The maximum cosmic ray energy achievable by acceleration by a relativistic blast wave is derived. It is shown that forward shocks from long GRB in the interstellar medium are powerful enough to produce the Galactic cosmic-ray component up to the ankle at $4\\times 10^{18}$eV, as per an earlier suggestion (Levinson and Eichler, 1993). It is further argued that, were extragalactic long GRB responsible for the component {\\it above} the ankle as well, the contribution from an occasional Galactic GRB within the solar circle would yield more than the observational limits on the outward flux from the solar circle, unless intermittency and/or beaming causes the present-day contribution to be less than $10^{-3}$ times the time average, and difficulties with these avoidance scenarios are also noted.

Eichler, David

2011-01-01T23:59:59.000Z

70

WINDS, CLUMPS, AND INTERACTING COSMIC RAYS IN M82  

SciTech Connect (OSTI)

We construct a family of models for the evolution of energetic particles in the starburst galaxy M82 and compare them to observations to test the calorimeter assumption that all cosmic ray energy is radiated in the starburst region. Assuming constant cosmic ray acceleration efficiency with Milky Way parameters, we calculate the cosmic-ray proton and primary and secondary electron/positron populations as a function of energy. Cosmic rays are injected with Galactic energy distributions and electron-to-proton ratio via Type II supernovae at the observed rate of 0.07 yr{sup -1}. From the cosmic ray spectra, we predict the radio synchrotron and {gamma}-ray spectra. To more accurately model the radio spectrum, we incorporate a multiphase interstellar medium in the starburst region of M82. Our model interstellar medium is highly fragmented with compact dense molecular clouds and dense photoionized gas, both embedded in a hot, low density medium in overall pressure equilibrium. The spectra predicted by this one-zone model are compared to the observed radio and {gamma}-ray spectra of M82. {chi}{sup 2} tests are used with radio and {gamma}-ray observations and a range of model predictions to find the best-fit parameters. The best-fit model yields constraints on key parameters in the starburst zone of M82, including a magnetic field strength of {approx}250 {mu}G and a wind advection speed in the range of 300-700 km s{sup -1}. We find that M82 is a good electron calorimeter but not an ideal cosmic-ray proton calorimeter and discuss the implications of our results for the astrophysics of the far-infrared-radio correlation in starburst galaxies.

Yoast-Hull, Tova M.; Everett, John E.; Zweibel, Ellen G. [Department of Physics, University of Wisconsin-Madison, WI (United States); Gallagher, J. S. III, E-mail: yoasthull@wisc.edu [Department of Astronomy, University of Wisconsin-Madison, WI (United States)

2013-05-01T23:59:59.000Z

71

Are gamma-ray bursts the sources of ultra-high energy cosmic rays?  

E-Print Network [OSTI]

We reconsider the possibility that gamma-ray bursts (GRBs) are the sources of the ultra-high energy cosmic rays (UHECRs) within the internal shock model, assuming a pure proton composition of the UHECRs. For the first time, we combine the information from gamma-rays, cosmic rays, prompt neutrinos, and cosmogenic neutrinos quantitatively in a joint cosmic ray production and propagation model, and we show that the information on the cosmic energy budget can be obtained as a consequence. In addition to the neutron model, we consider alternative scenarios for the cosmic ray escape from the GRBs, i.e., that cosmic rays can leak from the sources. We find that the dip model, which describes the ankle in UHECR observations by the pair production dip, is strongly disfavored in combination with the internal shock model because a) unrealistically high baryonic loadings (energy in protons versus energy in electrons/gamma-rays) are needed for the individual GRBs and b) the prompt neutrino flux easily overshoots the corresponding neutrino bound. On the other hand, GRBs may account for the UHECRs in the ankle transition model if cosmic rays leak out from the source at the highest energies. In that case, we demonstrate that future neutrino observations can efficiently test most of the parameter space -- unless the baryonic loading is much larger than previously anticipated.

Philipp Baerwald; Mauricio Bustamante; Walter Winter

2014-07-07T23:59:59.000Z

72

Are gamma-ray bursts the sources of ultra-high energy cosmic rays?  

Science Journals Connector (OSTI)

Abstract We reconsider the possibility that gamma-ray bursts (GRBs) are the sources of the ultra-high energy cosmic rays (UHECRs) within the internal shock model, assuming a pure proton composition of the UHECRs. For the first time, we combine the information from gamma-rays, cosmic rays, prompt neutrinos, and cosmogenic neutrinos quantitatively in a joint cosmic ray production and propagation model, and we show that the information on the cosmic energy budget can be obtained as a consequence. In addition to the neutron model, we consider alternative scenarios for the cosmic ray escape from the GRBs, i.e., that cosmic rays can leak from the sources. We find that the dip model, which describes the ankle in UHECR observations by the pair production dip, is strongly disfavored in combination with the internal shock model because (a) unrealistically high baryonic loadings (energy in protons versus energy in electrons/gamma-rays) are needed for the individual \\{GRBs\\} and (b) the prompt neutrino flux easily overshoots the corresponding neutrino bound. On the other hand, \\{GRBs\\} may account for the \\{UHECRs\\} in the ankle transition model if cosmic rays leak out from the source at the highest energies. In that case, we demonstrate that future neutrino observations can efficiently test most of the parameter space unless the baryonic loading is much larger than previously anticipated.

Philipp Baerwald; Mauricio Bustamante; Walter Winter

2015-01-01T23:59:59.000Z

73

Astrophysical Origins of the Highest Energy Cosmic Rays  

E-Print Network [OSTI]

Theoretical aspects of potential astrophysical sources of the highest energy cosmic rays are discussed, including their energy budget and some issues on particle escape and propagation. After briefly addressing AGN jets and GRBs, we highlight the possibility of heavy nuclei originating from cluster accretion shocks. The importance of X-ray and gamma-ray signatures in addition to neutrinos as diagnostic tools for source identification is emphasized.

Susumu Inoue

2007-02-01T23:59:59.000Z

74

Gamma ray bursts, cosmic ray origin, and the unidentified EGRET sources  

Science Journals Connector (OSTI)

Statistical arguments show that the volume- and time-averaged kinetic power of GRBs and fireball transients (FTs) into an L* galaxy like the Milky Way is at the level of 10 40 ? ergs?s ?1 . This number though with wide uncertainties related to the internal or external shock efficiency is sufficient to power hadronic cosmic rays observed locally. The release of energy by the high-mass progenitor stars of GRBs and FTs is sufficient to power the ultrahigh energy cosmic rays as already shown by Waxman and Vietri in 1995. It is sufficient to power the cosmic rays above the knee of the cosmic-ray spectrum. Indeed all hadronic cosmic rays could originate from the high-mass (?100? M ? ) stars that collapse to black holes in the process forming GRBs and FTs. This source class represents a new solution to the problem of cosmic-ray origin. The ?10 4 10 7 black holes made by these stars could make their presence known by radiating as they accrete from the ISM by microlensing background radiations and by forming luminous binary systems. Some unidentified EGRET sources could be isolated black holes that accrete from the ISM. Better imaging and sensitivity with GLAST and TeV observatories will test this model for the unidentified ?-ray sources and this theory for cosmic-ray origin.

Charles D. Dermer

2001-01-01T23:59:59.000Z

75

Ultrahigh Energy Cosmic Rays and Prompt TeV Gamma Rays from Gamma Ray Bursts  

E-Print Network [OSTI]

Gamma Ray Bursts (GRBs) have been proposed as one {\\it possible} class of sources of the Ultrahigh Energy Cosmic Ray (UHECR) events observed up to energies $\\gsim10^{20}\\ev$. The synchrotron radiation of the highest energy protons accelerated within the GRB source should produce gamma rays up to TeV energies. Here we briefly discuss the implications on the energetics of the GRB from the point of view of the detectability of the prompt TeV gamma rays of proton-synchrotron origin in GRBs in the up-coming ICECUBE muon detector in the south pole.

Pijushpani Bhattacharjee; Nayantara Gupta

2003-05-12T23:59:59.000Z

76

COSMIC RAY HEATING OF THE WARM IONIZED MEDIUM  

SciTech Connect (OSTI)

Observations of line ratios in the Milky Way's warm ionized medium suggest that photoionization is not the only heating mechanism present. For the additional heating to explain the discrepancy, it would have to have a weaker dependence on the gas density than the cooling rate, {Lambda}n{sub e}{sup 2}. Reynolds et al. suggested turbulent dissipation or magnetic field reconnection as possible heating sources. We investigate here the viability of MHD-wave mediated cosmic ray heating as a supplemental heating source. This heating rate depends on the gas density only through its linear dependence on the Alfven speed, which goes as n{sub e}{sup -1/2}. We show that, scaled to appropriate values of cosmic ray energy density, cosmic ray heating can be significant. Furthermore, this heating is stable to perturbations. These results should also apply to warm ionized gas in other galaxies.

Wiener, Joshua; Peng Oh, S. [Department of Physics, University of California, Santa Barbara, CA 93106 (United States)] [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Zweibel, Ellen G. [Departments of Astronomy and Physics, and Center for Magnetic Self-Organization, University of Wisconsin-Madison, Madison, WI 53706 (United States)] [Departments of Astronomy and Physics, and Center for Magnetic Self-Organization, University of Wisconsin-Madison, Madison, WI 53706 (United States)

2013-04-10T23:59:59.000Z

77

Origin and propagation of the highest energy cosmic rays  

E-Print Network [OSTI]

In this lecture I give an overview of shock acceleration, interactions of high energy cosmic rays with, and propagation through, the background radiation, and the resulting electron-photon cascade. I argue that while the origin of the highest energy cosmic rays is still uncertain, it is not necessary to invoke exotic models such as emission by topological defects to explain the existing data. It seems likely that shock acceleration at Fanaroff-Riley Class II radio galaxies can account for the existing data. However, new cosmic ray data, as well as better estimates of the extragalactic radiation fields and magnetic fields will be necessary before we will be certain of the origin of the highest energy particles occurring in nature.

R. J. Protheroe

1996-12-22T23:59:59.000Z

78

Cosmic Ray Acceleration by Spiral Shocks in the Galactic Wind  

E-Print Network [OSTI]

Cosmic ray acceleration by shocks related with Slipping Interaction Regions (SIRs) in the Galactic Wind is considered. SIRs are similar to Solar Wind Corotating Interaction Regions. The spiral structure of our Galaxy results in a strong nonuniformity of the Galactic Wind flow and in SIR formation at distances of 50 to 100 kpc. SIRs are not corotating with the gas and magnetic field because the angular velocity of the spiral pattern differs from that of the Galactic rotation. It is shown that the collective reacceleration of the cosmic ray particles with charge $Ze$ in the resulting shock ensemble can explain the observable cosmic ray spectrum beyond the "knee" up to energies of the order of $10^{17}Z$ eV. For the reaccelerated particles the Galactic Wind termination shock acts as a reflecting boundary.

H. J. Voelk; V. N. Zirakashvili

2004-01-19T23:59:59.000Z

79

Cosmic rays, lithium abundance and excess entropy in galaxy clusters  

E-Print Network [OSTI]

We consider the production of $^6$Li in spallation reactions by cosmic rays in order to explain the observed abundance in halo metal-poor stars. We show that heating of ambient gas by cosmic rays is an inevitable consequence of this process, and estimate the energy input required to reproduce the observed abundance of $^6$Li/H$\\sim 10^{-11}$ to be of order a few hundred eV per particle. We draw attention to the possibility that this could explain the excess entropy in gas in galaxy groups and clusters. The evolution of $^6$Li and the accompanying heating of gas is calculated for structures collapsing at the present epoch with injection of cosmic rays at high redshift. We determine the energy required to explain the abundance of $^6$Li at $z \\sim 2$ corresponding to the formation epoch of halo metal-poor stars, and also an increased entropy level of $\\sim 300$ keV cm$^2$ necessary to explain X-ray observations of clusters. The energy budget for this process is consistent with the expected energy output of radio-loud AGNs, and the diffusion length scale of cosmic-ray protons responsible for heating is comparable to the size of regions with excess entropy. We also discuss the constraints imposed by the extragalactic gamma-ray background.

Biman B. Nath; Piero Madau; Joseph Silk

2005-11-21T23:59:59.000Z

80

Cosmic Ray Sun Shadow in Soudan 2 Underground Muon Flux  

E-Print Network [OSTI]

The absorption of cosmic rays by the sun produces a shadow at the earth. The angular offset and broadening of the shadow are determined by the magnitude and structure of the interplanetary magnetic field (IPMF) in the inner solar system. We report the first measurement of the solar cosmic ray shadow by detection of deep underground muon flux in observations made during the entire ten-year interval 1989 to 1998. The sun shadow varies significantly during this time, with a $3.3\\sigma$ shadow observed during the years 1995 to 1998.

Soudan 2 Collaboration

1999-05-24T23:59:59.000Z

Note: This page contains sample records for the topic "int cosmic ray" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Energy spectrum of ultra high energy cosmic rays  

E-Print Network [OSTI]

The construction of the southern site of the Pierre Auger Observatory is almost completed. Three independent measurements of the flux of the cosmic rays with energies larger than 1 EeV have been performed during the construction phase. The surface detector data collected until August 2007 have been used to establish a flux suppression at the highest energies with a 6 sigma significance. The observations of cosmic rays by the fluorescence detector allowed the extension of the energy spectrum to lower energies, where the efficiency of the surface detector is less than 100% and a change in the spectral index is expected.

Ioana C. Maris; for the Pierre Auger Collaboration

2008-08-12T23:59:59.000Z

82

High-energy cosmic-ray muons at ground level and below ground level  

Science Journals Connector (OSTI)

Cosmic-ray muon interactions have been studied in an analysis of very recent measurements of cosmic-ray muons at sea-level and large depths underground ... By starting with the very carefully measured vertical muon

C. R. Paul; N. Chaudhuri

1977-01-11T23:59:59.000Z

83

E-Print Network 3.0 - average solar-cosmic-ray fluxes Sample...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

solar-cosmic-ray fluxes Search Powered by Explorit Topic List Advanced Search Sample search results for: average solar-cosmic-ray fluxes Page: << < 1 2 3 4 5 > >> 1 Annales...

84

RADIOGRAPHIC IMAGING BELOW A VOLCANIC CRATER FLOOR WITH COSMIC-RAY MUONS  

E-Print Network [OSTI]

horizontally-arriving cosmic ray muon with energy of 1 TeV can penetrate 2.6 km of water. Thus, cosmic-ray muon that uncertainty on the shape and amplitude of the energy spectrum of the muon source is within a few percentRADIOGRAPHIC IMAGING BELOW A VOLCANIC CRATER FLOOR WITH COSMIC-RAY MUONS HIROYUKI K.M. TANAKA

Aoki, Yosuke

85

EMMA an underground cosmic-ray experiment T. Enqvista  

E-Print Network [OSTI]

distribution function of high-energy muons. The rock overbur- den filters out all other charged particles of the air shower except the high-energy muons. The over- burden of 75 metres (corresponding to 210 m of cosmic rays at and above the knee region. The array, called EMMA (Experiment with MultiMuon Array

Usoskin, Ilya G.

86

Energy spectrum of cosmic-ray muons at sea level  

Science Journals Connector (OSTI)

The integral energy spectrum of cosmic-ray muons at sea level in the energy range (2007500) GeV is deduced ... this, the effect of fluctuations in the energy losses of muons is taken into account. The deduced muon

S. Miyake; V. S. Narasimham; P. V. Ramana Murthy

1964-01-16T23:59:59.000Z

87

Concerning the Nature of the Cosmic Ray Power Law Exponents  

E-Print Network [OSTI]

We have recently shown that the cosmic ray energy distributions as detected on earthbound, low flying balloon or high flying satellite detectors can be computed by employing the heats of evaporation of high energy particles from astrophysical sources. In this manner, the experimentally well known power law exponents of the cosmic ray energy distribution have been theoretically computed as 2.701178 for the case of ideal Bose statistics, 3.000000 for the case of ideal Boltzmann statistics and 3.151374 for the case of ideal Fermi statistics. By "ideal" we mean virtually zero mass (i.e. ultra-relativistic) and noninteracting. These results are in excellent agreement with the experimental indices of 2.7 with a shift to 3.1 at the high energy ~ PeV "knee" in the energy distribution. Our purpose here is to discuss the nature of cosmic ray power law exponents obtained by employing conventional thermal quantum field theoretical models such as quantum chromodynamics to the cosmic ray sources in a thermodynamic scheme wherein gamma and zeta function regulation is employed. The key reason for the surprising accuracy of the ideal boson and ideal fermion cases resides in the asymptotic freedom or equivalently the Feynman "parton" structure of the ultra-high energy tails of spectral functions.

A. Widom; J. Swain; Y. N. Srivastava

2014-10-15T23:59:59.000Z

88

Cosmic Ray Pitch Angle Scattering Through 90 o  

E-Print Network [OSTI]

Cosmic Ray Pitch Angle Scattering Through 90 o G.M. Felice 1 and R.M. Kulsrud 2 Princeton Plasma­ lar attention to the problem of particle scattering through the # = cos -1 (v # /v) = 90 o pitch angle their pitch angle by mirror interaction with long wavelength waves generated by the # # 0 particles. We match

89

Concerning the Nature of the Cosmic Ray Power Law Exponents  

E-Print Network [OSTI]

We have recently shown that the cosmic ray energy distributions as detected on earthbound, low flying balloon or high flying satellite detectors can be computed by employing the heats of evaporation of high energy particles from astrophysical sources. In this manner, the experimentally well known power law exponents of the cosmic ray energy distribution have been theoretically computed as 2.701178 for the case of ideal Bose statistics, 3.000000 for the case of ideal Boltzmann statistics and 3.151374 for the case of ideal Fermi statistics. By "ideal" we mean virtually zero mass (i.e. ultra-relativistic) and noninteracting. These results are in excellent agreement with the experimental indices of 2.7 with a shift to 3.1 at the high energy ~ PeV "knee" in the energy distribution. Our purpose here is to discuss the nature of cosmic ray power law exponents obtained by employing conventional thermal quantum field theoretical models such as quantum chromodynamics to the cosmic ray sources in a thermodynamic scheme w...

Widom, A; Srivastava, Y N

2014-01-01T23:59:59.000Z

90

Ultra-high energy cosmic rays from Quark Novae  

E-Print Network [OSTI]

We explore acceleration of ions in the Quark Nova (QN) scenario, where a neutron star experiences an explosive phase transition into a quark star (born in the propeller regime). In this picture, two cosmic ray components are isolated: one related to the randomized pulsar wind and the other to the propelled wind, both boosted by the ultra-relativistic Quark Nova shock. The latter component acquires energies $10^{15} {\\rm eV}wind, achieves ultra-high energies $E> 10^{18.6}$ eV. The composition is dominated by ions present in the pulsar wind in the energy range above $10^{18.6}$ eV, while at energies below $10^{18}$ eV the propelled ejecta, consisting of the fall-back neutron star crust material from the explosion, is the dominant one. Added to these two components, the propeller injects relativistic particles with Lorentz factors $\\Gamma_{\\rm prop.} \\sim 1-1000$, later to be accelerated by galactic supernova shocks. The QN model appears to be able to account for the extragalactic cosmic rays above the ankle and to contribute a few percent of the galactic cosmic rays below the ankle. We predict few hundred ultra-high energy cosmic ray events above $10^{19}$ eV for the Pierre Auger detector per distant QN, while some thousands are predicted for the proposed EUSO and OWL detectors.

R. Ouyed; P. Kernen; J. Maalampi

2003-01-29T23:59:59.000Z

91

Angular correlation of cosmic neutrinos with ultrahigh-energy cosmic rays and implications for their sources  

E-Print Network [OSTI]

Cosmic neutrino events detected by the IceCube Neutrino Observatory with energy $\\gtrsim 30$ TeV have poor angular resolutions to reveal their origin. Ultrahigh-energy cosmic rays (UHECRs), with better angular resolutions at $>60$ EeV energies, can be used to check if the same astrophysical sources are responsible for producing both neutrinos and UHECRs. We test this hypothesis, with statistical methods which emphasize invariant quantities, by using data from the Pierre Auger Observatory, Telescope Array and past cosmic-ray experiments. We find that the arrival directions of the cosmic neutrinos are correlated with $\\ge 100$ EeV UHECR arrival directions at confidence level $\\approx 93\\%$. The strength of the correlation decreases with decreasing UHECR energy and no correlation exists at energy $\\sim 60$ EeV. A search in astrophysical databases within $3^\\circ$ of the arrival directions of UHECRs with energy $\\ge 100$ EeV, that are correlated with the IceCube cosmic neutrinos, resulted in 18 sources from the S...

Moharana, Reetanjali

2015-01-01T23:59:59.000Z

92

Further Study of Cosmic Rays on the Pacific Ocean  

Science Journals Connector (OSTI)

Records of cosmic-ray intensity obtained on the R. M. S. Aorangi during 15 new voyages between Vancouver, Canada, and Sydney, Australia, from July 28, 1937, to September 23, 1938, with a Carnegie model C cosmic-ray meter, are discussed and compared with records taken during 11 voyages on the same route previously reported by Compton and Turner. The observed minimum of cosmic-ray intensity near the equator averages 10.3 percent less than the intensity at Vancouver, in good agreement with the value given by Compton and Turner. The correlation between the cosmic-ray intensity and the atmospheric temperature is confirmed. An atmospheric temperature coefficient is found to be a function of latitude, with its highest numerical value of -0.25 percent per C for latitudes higher than 40 (N and S). With this variable temperature coefficient a latitude effect (about 8.5 percent) of magnetic origin alone is found. The mean latitude effect curve for 25 trips, corrected for external temperature, is flat beyond the critical latitudes (about 40N and 38S). The difference in cosmic-ray intensity between the Northern and Southern Hemispheres beyond the critical latitudes after this temperature correction is found to be 00.1 percent (probable error). This is inconsistent with a galactic rotation effect as great as the 0.5 percent predicted by Compton and Getting, but does not definitely rule out a more recent modification of their calculation. The origin of the latitude effect knee is ascribed to the minimum energy required for a primary electron to produce mesotrons capable of traversing the atmosphere. The small magnitude of the latitude effect is shown to supply strong evidence of the secondary nature of mesotrons.

Piara S. Gill

1939-06-15T23:59:59.000Z

93

Cosmic rays, lithium abundance and excess entropy in galaxy clusters  

E-Print Network [OSTI]

We consider the production of $^6$Li in spallation reactions by cosmic rays in order to explain the observed abundance in halo metal-poor stars. We show that heating of ambient gas by cosmic rays is an inevitable consequence of this process, and estimate the energy input required to reproduce the observed abundance of $^6$Li/H$\\sim 10^{-11}$ to be of order a few hundred eV per particle. We draw attention to the possibility that this could explain the excess entropy in gas in galaxy groups and clusters. The evolution of $^6$Li and the accompanying heating of gas is calculated for structures collapsing at the present epoch with injection of cosmic rays at high redshift. We determine the energy required to explain the abundance of $^6$Li at $z \\sim 2$ corresponding to the formation epoch of halo metal-poor stars, and also an increased entropy level of $\\sim 300$ keV cm$^2$ necessary to explain X-ray observations of clusters. The energy budget for this process is consistent with the expected energy output of radi...

Nath, B B; Silk, J; Nath, Biman B.; Madau, Piero; Silk, Joseph

2006-01-01T23:59:59.000Z

94

CAN ULTRAHIGH-ENERGY COSMIC RAYS COME FROM GAMMA-RAY BURSTS? COSMIC RAYS BELOW THE ANKLE AND GALACTIC GAMMA-RAY BURSTS  

SciTech Connect (OSTI)

The maximum cosmic-ray energy achievable by acceleration by a relativistic blast wave is derived. It is shown that forward shocks from long gamma-ray bursts (GRBs) in the interstellar medium accelerate protons to large enough energies, and have a sufficient energy budget, to produce the Galactic cosmic-ray component just below the ankle at 4 x 10{sup 18} eV, as per an earlier suggestion. It is further argued that, were extragalactic long GRBs responsible for the component above the ankle as well, the occasional Galactic GRB within the solar circle would contribute more than the observational limits on the outward flux from the solar circle, unless an avoidance scenario, such as intermittency and/or beaming, allows the present-day local flux to be less than 10{sup -3} of the average. Difficulties with these avoidance scenarios are noted.

Eichler, David [Physics Department, Ben-Gurion University, Be'er-Sheva 84105 (Israel); Pohl, Martin [Institut fuer Physik und Astronomie, Universitaet Potsdam, 14476 Potsdam-Golm (Germany)

2011-09-10T23:59:59.000Z

95

Can Ultrahigh-energy Cosmic Rays Come from Gamma-Ray Bursts? Cosmic Rays Below the Ankle and Galactic Gamma-Ray Bursts  

Science Journals Connector (OSTI)

The maximum cosmic-ray energy achievable by acceleration by a relativistic blast wave is derived. It is shown that forward shocks from long gamma-ray bursts (GRBs) in the interstellar medium accelerate protons to large enough energies, and have a sufficient energy budget, to produce the Galactic cosmic-ray component just below the ankle at 4 ? 1018 eV, as per an earlier suggestion. It is further argued that, were extragalactic long GRBs responsible for the component above the ankle as well, the occasional Galactic GRB within the solar circle would contribute more than the observational limits on the outward flux from the solar circle, unless an avoidance scenario, such as intermittency and/or beaming, allows the present-day local flux to be less than 103 of the average. Difficulties with these avoidance scenarios are noted.

David Eichler; Martin Pohl

2011-01-01T23:59:59.000Z

96

Ankle phenomenon in the cosmic ray energy spectrum  

E-Print Network [OSTI]

The author has suggested that the knee phenomenon in the cosmic ray energy spectrum at 3 PeV can be explained as a split between a radiation-dominated expansion and a matter-dominated expansion of an expanding heat bath. The model proposed in 1985, in fact, predicted that high energy cosmic rays are emitted from AGN, massive black holes, in agreement with recent data from the Pierre Auger Observatory. Similarly, the ankle phenomenon at 3 EeV is shown to be explained by a split between inflational expansion and ordinary material expansion of the expanding heat bath, not unlike that in the expansion of the universe. All the spectral indicies in the respective regions of the energy spectra agree with the theoretical calculation from the respective expansion rates.

Yukio Tomozawa

2012-08-22T23:59:59.000Z

97

Ankle phenomenon in the cosmic ray energy spectrum  

E-Print Network [OSTI]

The author has suggested that the knee phenomenon in the cosmic ray energy spectrum at 3 PeV can be explained as a split between a radiation-dominated expansion and a matter-dominated expansion of an expanding heat bath. The model proposed in 1985, in fact, predicted that high energy cosmic rays are emitted from AGN, massive black holes, in agreement with recent data from the Pierre Auger Observatory. Similarly, the ankle phenomenon at 3 EeV is shown to be explained by a split between inflational expansion and ordinary material expansion of the expanding heat bath, not unlike that in the expansion of the universe. All the spectral indicies in the respective regions of the energy spectra agree with the theoretical calculation from the respective expansion rates.

Tomozawa, Yukio

2012-01-01T23:59:59.000Z

98

Cosmic Rays and Terrestrial Life: a Brief Review  

E-Print Network [OSTI]

"The investigation into the possible effects of cosmic rays on living organisms will also offer great interest." - Victor F. Hess, Nobel Lecture, December 12, 1936 High-energy radiation bursts are commonplace in our Universe. From nearby solar flares to distant GRBs, a variety of physical processes accelerate charged particles in a wide energy range, which subsequently reach the Earth. Such particles interact with, and contribute to a number of physical processes occurring in the Earth system. A large fraction of the energy of charged particles gets deposited in the atmosphere, ionizing the atmosphere, causing changes in atmospheric chemistry and affecting the global electric circuit. Remaining secondary particles contribute to the background dose of cosmic rays on the surface and parts of the subsurface region. Life has evolved since past ~ 3 billion years in presence of this background radiation, which itself has varied considerably during the period [1-3]. As demonstrated by the Miller-Urey experiment, lig...

Atri, Dimitra

2012-01-01T23:59:59.000Z

99

Muon Production in Relativistic Cosmic-Ray Interactions  

SciTech Connect (OSTI)

Cosmic-rays with energies up to 3x1020 eV have been observed. The nuclear composition of these cosmic rays is unknown but if the incident nuclei are protons then the corresponding center of mass energy is sqrt snn = 700 TeV. High energy muons can be used to probe the composition of these incident nuclei. The energy spectra of high-energy (> 1 TeV) cosmic ray induced muons have been measured with deep underground or under-ice detectors. These muons come from pion and kaon decays and from charm production in the atmosphere. Terrestrial experiments are most sensitive to far-forward muons so the production rates aresensitive to high-x partons in the incident nucleus and low-x partons in the nitrogen/oxygen targets. Muon measurements can complement the central-particle data collected at colliders.This paper will review muon production data and discuss some non-perturbative (soft) models that have been used to interpret the data. I will show measurements of TeV muon transverse momentum (pT) spectra in cosmic-ray air showers fromMACRO, and describe how the IceCube neutrino observatory and the proposed Km3Net detector will extend these measurements to a higher pT region where perturbative QCD should apply. With a 1 km2 surface area, the full IceCube detector should observe hundreds of muons/year with pT in the pQCD regime.

Klein, Spencer

2009-07-27T23:59:59.000Z

100

Magnetic horizons of ultra-high energy cosmic rays  

E-Print Network [OSTI]

The propagation of ultra-high energy cosmic rays in extragalactic magnetic fields can be diffusive, depending on the strength and properties of the fields. In some cases the propagation time of the particles can be comparable to the age of the universe, causing a suppression in the flux measured on Earth. In this work we use magnetic field distributions from cosmological simulations to assess the existence of a magnetic horizon at energies around 10$^{18}$ eV.

Batista, Rafael Alves

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "int cosmic ray" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

High Energy Cosmic Rays from Local GRBs Armen Atoyan1  

E-Print Network [OSTI]

with energies E between 0.1 - 1 PeV and the energy of the second knee at E2 3 ? 1017 eV as originating from. The origin of the ankle in the CR spectrum at Eank 4 ? 1018 eV is due to photopair energy losses of UHECRsHigh Energy Cosmic Rays from Local GRBs Armen Atoyan1 and Charles D. Dermer2 1 CRM, Universit´e de

102

Double Pair Production by Ultra High Energy Cosmic Ray Photons  

E-Print Network [OSTI]

With use of CompHEP package we've made the detailed estimate of the influence of double e+e- pair production by photons (DPP) on the propagation of ultra high energy electromagnetic cascade. We show that in the models in which cosmic ray photons energy reaches few thousand EeV refined DPP analysis may lead to substantial difference in predicted photon spectrum compared to previous rough estimates.

S. V. Demidov; O. E. Kalashev

2008-12-22T23:59:59.000Z

103

Synchrotron Radiation at Radio Frequencies from Cosmic Ray Air Showers  

E-Print Network [OSTI]

We review some of the properties of extensive cosmic ray air showers and describe a simple model of the radio-frequency radiation generated by shower electrons and positrons as they bend in the Earth's magnetic field. We perform simulations by calculating the trajectory and radiation of a few thousand charged shower particles. The results are then transformed to predict the strength and polarization of the electromagnetic radiation emitted by the whole shower.

Denis A. Suprun; Peter W. Gorham; Jonathan L. Rosner

2003-06-06T23:59:59.000Z

104

Synchrotron Radiation at Radio Frequencies from Cosmic Ray Air Showers  

E-Print Network [OSTI]

We review some of the properties of extensive cosmic ray air showers and describe a simple model of the radio-frequency radiation generated by shower electrons and positrons as they bend in the Earth's magnetic field. We perform simulations by calculating the trajectory and radiation of a few thousand charged shower particles. The results are then transformed to predict the strength and polarization of the electromagnetic radiation emitted by the whole shower.

Suprun, D A; Rosner, Jonathan L; Suprun, Denis A.; Gorham, Peter W.; Rosner, Jonathan L.

2003-01-01T23:59:59.000Z

105

Development of atmospheric cosmic-ray showers. II  

Science Journals Connector (OSTI)

In a recent paper Orford and Turver criticized one of our previous papers which had concluded that a change in cosmic-ray primary mass composition was required in the energy range 1015 to 1017 eV. It is suggested here, in reply, that the inconsistencies and shortcomings claimed by Orford and Turver are largely not substantiated in the light of available information and that, in the absence of new ideas, the original conclusions are valid.

Greg Thornton and Roger Clay

1981-05-01T23:59:59.000Z

106

On the spectrum of Ultrahigh Energy Cosmic Rays and the Gamma Ray Burst Origin Hypothesis  

E-Print Network [OSTI]

It has been suggested that cosmological gamma-ray bursts (GRBs) can produce the observed flux of cosmic rays at the highest energies. However, recent studies of GRBs indicate that their redshift distribution likely follows that of the average star formation rate and that GRBs were more numerous at high redshifts. As a consequence, we show that photomeson production energy losses suffered by ultrahigh energy cosmic rays coming from GRBs would produce too sharp a spectral high energy cutoff to be consistent with the air shower data. Furthermore, we show that cosmological GRBs fail to supply the energy input required to account for the cosmic ray flux above 10 EeV by a factor of 100-1000.

S. T. Scully; F. W. Stecker

2000-06-08T23:59:59.000Z

107

COSMIC-RAY AND X-RAY HEATING OF INTERSTELLAR CLOUDS AND PROTOPLANETARY DISKS  

SciTech Connect (OSTI)

Cosmic-ray and X-ray heating are derived from the electron energy-loss calculations of Dalgarno, Yan, and Liu for hydrogen-helium gas mixtures. These authors treated the heating from elastic scattering and collisional de-excitation of rotationally excited hydrogen molecules. Here we consider the heating that can arise from all ionization and excitation processes, with particular emphasis on the reactions of cosmic-ray and X-ray generated ions with the heavy neutral species, which we refer to as chemical heating. In molecular regions, chemical heating dominates and can account for 50% of the energy expended in the creation of an ion pair. The heating per ion pair ranges in the limit of negligible electron fraction from {approx}4.3 eV for diffuse atomic gas to {approx}13 eV for the moderately dense regions of molecular clouds and to {approx}18 eV for the very dense regions of protoplanetary disks. An important general conclusion of this study is that cosmic-ray and X-ray heating depends on the physical properties of the medium, i.e., on the molecular and electron fractions, the total density of hydrogen nuclei, and, to a lesser extent, on the temperature. It is also noted that chemical heating, the dominant process for cosmic-ray and X-ray heating, plays a role in UV irradiated molecular gas.

Glassgold, Alfred E. [Astronomy Department, University of California, Berkeley, CA 94720-3411 (United States); Galli, Daniele [INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 (Italy); Padovani, Marco, E-mail: aglassgold@berkeley.edu, E-mail: galli@arcetri.astro.it, E-mail: marco.padovani@lra.ens.fr [Laboratoire de Radioastronomie Millimetrique, UMR 8112 du CNRS, Ecole Normale Superieure et Observatoire de Paris, 24 rue Lhomond, F-75231 Paris Cedex 05 (France)

2012-09-10T23:59:59.000Z

108

Cosmic-ray Driven Outflows in Global Galaxy Disk Models  

E-Print Network [OSTI]

Galactic-scale winds are a generic feature of massive galaxies with high star formation rates across a broad range of redshifts. Despite their importance, a detailed physical understanding of what drives these mass-loaded global flows has remained elusive. In this paper, we explore the dynamical impact of cosmic rays by performing the first three-dimensional, adaptive mesh refinement simulations of an isolated starbursting galaxy that includes a basic model for the production, dynamics and diffusion of galactic cosmic rays. We find that including cosmic rays naturally leads to robust, massive, bipolar outflows from our 10^12 Msun halo, with a mass-loading factor Mout/SFR = 0.3 for our fiducial run. Other reasonable parameter choices led to mass-loading factors above unity. The wind is multiphase and is accelerated to velocities well in excess of the escape velocity. We employ a two-fluid model for the thermal gas and relativistic CR plasma and model a range of physics relevant to galaxy formation, including r...

Salem, Munier

2013-01-01T23:59:59.000Z

109

On the ultra high energy cosmic rays and the origin of the cosmic microwave background radiation  

E-Print Network [OSTI]

Some inconsistencies to the assumption of a cosmological origin of the cosmic microwave background CMB, such as the absence of gravitational lensing in the WMAP data, open the doors to some speculations such as a local origin to the CMB. We argue here that this assumption agrees with the absence of the GZK cutoff (at least according to AGASA data) in the energy spectrum of the cosmic ray due to the cosmic interaction with the CMB at $6\\times 10^{19} eV$ or above. Within 50 Mpc from Earth, the matter and light distributions are close to an anisotropic distribution, where the local cluster and local super-clusters of galaxies can be identified. In contrast, the ultra high energy comic rays data is consistent to an almost isotropic distribution, and there is no correlation between their arrival direction and astronomical sources within our local cluster. This means that the events above the GZK cutoff come from distances above 50 Mpc, without an apparent energy loss. This scenario is plausible under the assumption of the CMB concentrated only within 3-4 Mpc from Earth. In other words, the CMB has a local origin linked only to the local super-cluster of galaxies. In addition, the galactic and extragalactic energy spectra index within the energy equipartition theorem strongly constrains the dark matter and dark energy hypothesis, essential in the Big Bang cosmology.

C. E. Navia; C. R. A. Augusto; K. H. Tsui

2007-07-12T23:59:59.000Z

110

Cosmic Rays from Supernovae Proven to Hit Earth | Department of Energy  

Broader source: Energy.gov (indexed) [DOE]

Cosmic Rays from Supernovae Proven to Hit Earth Cosmic Rays from Supernovae Proven to Hit Earth Cosmic Rays from Supernovae Proven to Hit Earth March 5, 2013 - 4:40pm Addthis When stars explode, the supernovas send off shock waves like the one shown in this artist's rendition, which accelerate protons to cosmic-ray energies through a process known as Fermi acceleration. Andy Freeberg SLAC National Accelerator Laboratory Did you know? Protons make up 90 percent of the cosmic rays that hit Earth's atmosphere, triggering showers of particles that reach the ground and creating radiation for air travelers. The energies of these protons as they leave the supernovae are far beyond what the most powerful particle colliders on Earth can produce. Cosmic rays, energetic particles that pelt Earth, are born in the violent

111

Stochastic simulation of cosmic ray modulation including a wavy heliospheric current sheet  

E-Print Network [OSTI]

ray transport in the vicinity of the heliospheric current sheet (HCS), and a new method to calculate-dimensional (axisymmetric) model of the heliospheric transport of galactic cosmic rays. The model is based on stochastic and the dominant streaming patterns of cosmic rays in the heliosphere for different solar polarities and HCS tilt

Usoskin, Ilya G.

112

The Pierre Auger Observatory II: Studies of Cosmic Ray Composition and Hadronic Interaction models  

E-Print Network [OSTI]

Studies of the composition of the highest energy cosmic rays with the Pierre Auger Observatory, including examination of hadronic physics effects on the structure of extensive air showers.

The Pierre Auger Collaboration; P. Abreu; M. Aglietta; E. J. Ahn; I. F. M. Albuquerque; D. Allard; I. Allekotte; J. Allen; P. Allison; J. Alvarez Castillo; J. Alvarez-Muiz; M. Ambrosio; A. Aminaei; L. Anchordoqui; S. Andringa; T. Anti?i?; A. Anzalone; C. Aramo; E. Arganda; F. Arqueros; H. Asorey; P. Assis; J. Aublin; M. Ave; M. Avenier; G. Avila; T. Bcker; M. Balzer; K. B. Barber; A. F. Barbosa; R. Bardenet; S. L. C. Barroso; B. Baughman; J. Buml; J. J. Beatty; B. R. Becker; K. H. Becker; A. Belltoile; J. A. Bellido; S. BenZvi; C. Berat; X. Bertou; P. L. Biermann; P. Billoir; F. Blanco; M. Blanco; C. Bleve; H. Blmer; M. Boh?ov; D. Boncioli; C. Bonifazi; R. Bonino; N. Borodai; J. Brack; P. Brogueira; W. C. Brown; R. Bruijn; P. Buchholz; A. Bueno; R. E. Burton; K. S. Caballero-Mora; L. Caramete; R. Caruso; A. Castellina; O. Catalano; G. Cataldi; L. Cazon; R. Cester; J. Chauvin; S. H. Cheng; A. Chiavassa; J. A. Chinellato; A. Chou; J. Chudoba; R. W. Clay; M. R. Coluccia; R. Conceio; F. Contreras; H. Cook; M. J. Cooper; J. Coppens; A. Cordier; U. Cotti; S. Coutu; C. E. Covault; A. Creusot; A. Criss; J. Cronin; A. Curutiu; S. Dagoret-Campagne; R. Dallier; S. Dasso; K. Daumiller; B. R. Dawson; R. M. de Almeida; M. De Domenico; C. De Donato; S. J. de Jong; G. De La Vega; W. J. M. de Mello Junior; J. R. T. de Mello Neto; I. De Mitri; V. de Souza; K. D. de Vries; G. Decerprit; L. del Peral; O. Deligny; H. Dembinski; N. Dhital; C. Di Giulio; J. C. Diaz; M. L. Daz Castro; P. N. Diep; C. Dobrigkeit; W. Docters; J. C. D'Olivo; P. N. Dong; A. Dorofeev; J. C. dos Anjos; M. T. Dova; D. D'Urso; I. Dutan; J. Ebr; R. Engel; M. Erdmann; C. O. Escobar; A. Etchegoyen; P. Facal San Luis; I. Fajardo Tapia; H. Falcke; G. Farrar; A. C. Fauth; N. Fazzini; A. P. Ferguson; A. Ferrero; B. Fick; A. Filevich; A. Filip?i?; S. Fliescher; C. E. Fracchiolla; E. D. Fraenkel; U. Frhlich; B. Fuchs; R. Gaior; R. F. Gamarra; S. Gambetta; B. Garca; D. Garca Gmez; D. Garcia-Pinto; A. Gascon; H. Gemmeke; K. Gesterling; P. L. Ghia; U. Giaccari; M. Giller; H. Glass; M. S. Gold; G. Golup; F. Gomez Albarracin; M. Gmez Berisso; P. Gonalves; D. Gonzalez; J. G. Gonzalez; B. Gookin; D. Gra; A. Gorgi; P. Gouffon; S. R. Gozzini; E. Grashorn; S. Grebe; N. Griffith; M. Grigat; A. F. Grillo; Y. Guardincerri; F. Guarino; G. P. Guedes; A. Guzman; J. D. Hague; P. Hansen; D. Harari; S. Harmsma; J. L. Harton; A. Haungs; T. Hebbeker; D. Heck; A. E. Herve; C. Hojvat; N. Hollon; V. C. Holmes; P. Homola; J. R. Hrandel; A. Horneffer; M. Hrabovsk; T. Huege; A. Insolia; F. Ionita; A. Italiano; C. Jarne; S. Jiraskova; M. Josebachuili; K. Kadija; K. -H. Kampert; P. Karhan; P. Kasper; B. Kgl; B. Keilhauer; A. Keivani; J. L. Kelley; E. Kemp; R. M. Kieckhafer; H. O. Klages; M. Kleifges; J. Kleinfeller; J. Knapp; D. -H. Koang; K. Kotera; N. Krohm; O. Krmer; D. Kruppke-Hansen; F. Kuehn; D. Kuempel; J. K. Kulbartz; N. Kunka; G. La Rosa; C. Lachaud; P. Lautridou; M. S. A. B. Leo; D. Lebrun; P. Lebrun; M. A. Leigui de Oliveira; A. Lemiere; A. Letessier-Selvon; I. Lhenry-Yvon; K. Link; R. Lpez; A. Lopez Agera; K. Louedec; J. Lozano Bahilo; A. Lucero; M. Ludwig; H. Lyberis; M. C. Maccarone; C. Macolino; S. Maldera; D. Mandat; P. Mantsch; A. G. Mariazzi; J. Marin; V. Marin; I. C. Maris; H. R. Marquez Falcon; G. Marsella; D. Martello; L. Martin; H. Martinez; O. Martnez Bravo; H. J. Mathes; J. Matthews; J. A. J. Matthews; G. Matthiae; D. Maurizio; P. O. Mazur; G. Medina-Tanco; M. Melissas; D. Melo; E. Menichetti; A. Menshikov; P. Mertsch; C. Meurer; S. Mi?anovi?; M. I. Micheletti; W. Miller; L. Miramonti; S. Mollerach; M. Monasor; D. Monnier Ragaigne; F. Montanet; B. Morales; C. Morello; E. Moreno; J. C. Moreno; C. Morris; M. Mostaf; C. A. Moura; S. Mueller; M. A. Muller; G. Mller; M. Mnchmeyer; R. Mussa; G. Navarra; J. L. Navarro; S. Navas; P. Necesal; L. Nellen; A. Nelles; J. Neuser; P. T. Nhung; L. Niemietz; N. Nierstenhoefer; D. Nitz; D. Nosek; L. Noka; M. Nyklicek; J. Oehlschlger; A. Olinto; V. M. Olmos-Gilbaja; M. Ortiz; N. Pacheco; D. Pakk Selmi-Dei; M. Palatka; J. Pallotta; N. Palmieri; G. Parente; E. Parizot; A. Parra; R. D. Parsons; S. Pastor; T. Paul; M. Pech; J. P?kala; R. Pelayo; I. M. Pepe; L. Perrone; R. Pesce; E. Petermann; S. Petrera; P. Petrinca; A. Petrolini; Y. Petrov; J. Petrovic; C. Pfendner; N. Phan; R. Piegaia; T. Pierog; P. Pieroni; M. Pimenta; V. Pirronello; M. Platino; V. H. Ponce; M. Pontz; P. Privitera; M. Prouza; E. J. Quel; S. Querchfeld; J. Rautenberg; O. Ravel; D. Ravignani; B. Revenu; J. Ridky; S. Riggi; M. Risse; P. Ristori; H. Rivera; V. Rizi; J. Roberts; C. Robledo; W. Rodrigues de Carvalho; G. Rodriguez; J. Rodriguez Martino; J. Rodriguez Rojo; I. Rodriguez-Cabo; M. D. Rodrguez-Fras; G. Ros; J. Rosado

2011-07-24T23:59:59.000Z

113

Los Alamos, Toshiba probing Fukushima with cosmic rays  

ScienceCinema (OSTI)

Los Alamos National Laboratory has announced an impending partnership with Toshiba Corporation to use a Los Alamos technique called muon tomography to safely peer inside the cores of the Fukushima Daiichi reactors and create high-resolution images of the damaged nuclear material inside without ever breaching the cores themselves. The initiative could reduce the time required to clean up the disabled complex by at least a decade and greatly reduce radiation exposure to personnel working at the plant. Muon radiography (also called cosmic-ray radiography) uses secondary particles generated when cosmic rays collide with upper regions of Earth's atmosphere to create images of the objects that the particles, called muons, penetrate. The process is analogous to an X-ray image, except muons are produced naturally and do not damage the materials they contact. Muon radiography has been used before in imaginative applications such as mapping the interior of the Great Pyramid at Giza, but Los Alamos's muon tomography technique represents a vast improvement over earlier technology.

Morris, Christopher

2014-06-25T23:59:59.000Z

114

Los Alamos, Toshiba probing Fukushima with cosmic rays  

SciTech Connect (OSTI)

Los Alamos National Laboratory has announced an impending partnership with Toshiba Corporation to use a Los Alamos technique called muon tomography to safely peer inside the cores of the Fukushima Daiichi reactors and create high-resolution images of the damaged nuclear material inside without ever breaching the cores themselves. The initiative could reduce the time required to clean up the disabled complex by at least a decade and greatly reduce radiation exposure to personnel working at the plant. Muon radiography (also called cosmic-ray radiography) uses secondary particles generated when cosmic rays collide with upper regions of Earth's atmosphere to create images of the objects that the particles, called muons, penetrate. The process is analogous to an X-ray image, except muons are produced naturally and do not damage the materials they contact. Muon radiography has been used before in imaginative applications such as mapping the interior of the Great Pyramid at Giza, but Los Alamos's muon tomography technique represents a vast improvement over earlier technology.

Morris, Christopher

2014-06-16T23:59:59.000Z

115

Constraints on particle dark matter from cosmic-ray antiprotons  

E-Print Network [OSTI]

Cosmic-ray antiprotons represent an important channel for dark matter indirect-detection studies. Current measurements of the antiproton flux at the top of the atmosphere and theoretical determinations of the secondary antiproton production in the Galaxy are in good agreement, with no manifest deviation which could point to an exotic contribution in this channel. Therefore, antiprotons can be used as a powerful tool for constraining particle dark matter properties. By using the spectrum of PAMELA data from 50 MV to 180 GV in rigidity, we derive bounds on the dark matter annihilation cross section (or decay rate, for decaying dark matter) for the whole spectrum of dark matter annihilation (decay) channels and under different hypotheses of cosmic-rays transport in the Galaxy and in the heliosphere. For typical models of galactic propagation, the constraints are significantly strong, setting a lower bound on the dark matter mass of a "thermal" relic at about 50 -- 90 GeV for hadronic annihilation channels. These bounds are enhanced to about 150 GeV on the dark matter mass, when large cosmic-rays confinement volumes in the Galaxy are considered, and are reduced to 4-5 GeV for annihilation to light quarks (no bound for heavy-quark production) when the confinement volume is small. Bounds for dark matter lighter than few tens of GeV are due to the low energy part of the PAMELA spectrum, an energy region where solar modulation is relevant: to this aim, we have implemented a detailed solution of the transport equation in the heliosphere, which allowed us not only to extend bounds to light dark matter, but also to determine the uncertainty on the constraints arising from solar modulation modeling. Finally, we estimate the impact of soon-to-come AMS-02 data on the antiproton constraints.

N. Fornengo; L. Maccione; A. Vittino

2013-12-12T23:59:59.000Z

116

Constraints on particle dark matter from cosmic-ray antiprotons  

E-Print Network [OSTI]

Cosmic-ray antiprotons represent an important channel for dark matter indirect-detection studies. Current measurements of the antiproton flux at the top of the atmosphere and theoretical determinations of the secondary antiproton production in the Galaxy are in good agreement, with no manifest deviation which could point to an exotic contribution in this channel. Therefore, antiprotons can be used as a powerful tool for constraining particle dark matter properties. By using the spectrum of PAMELA data from 50 MV to 180 GV in rigidity, we derive bounds on the dark matter annihilation cross section (or decay rate, for decaying dark matter) for the whole spectrum of dark matter annihilation (decay) channels and under different hypotheses of cosmic-rays transport in the Galaxy and in the heliosphere. For typical models of galactic propagation, the constraints are significantly strong, setting a lower bound on the dark matter mass of a "thermal" relic at about 50-90 GeV for hadronic annihilation channels. These bounds are enhanced to about 150 GeV on the dark matter mass, when large cosmic-rays confinement volumes in the Galaxy are considered, and are reduced to 4-5 GeV for annihilation to light quarks (no bound for heavy-quark production) when the confinement volume is small. Bounds for dark matter lighter than few tens of GeV are due to the low energy part of the PAMELA spectrum, an energy region where solar modulation is relevant: to this aim, we have implemented a detailed solution of the transport equation in the heliosphere, which allowed us not only to extend bounds to light dark matter, but also to determine the uncertainty on the constraints arising from solar modulation modeling. Finally, we estimate the impact of soon-to-come AMS-02 data on the antiproton constraints.

N. Fornengo; L. Maccione; A. Vittino

2015-01-30T23:59:59.000Z

117

Gamma-Ray Bursts and Quantum Cosmic Censorship  

E-Print Network [OSTI]

Gamma-ray bursts are believed to result from the coalescence of binary neutron stars. However, the standard proposals for conversion of the gravitational energy to thermal energy have difficulties. We show that if the merger of the two neutron stars results in a naked singularity, instead of a black hole, the ensuing quantum particle creation can provide the requisite thermal energy in a straightforward way. The back-reaction of the created particles can avoid the formation of the naked singularity predicted by the classical theory. Hence cosmic censorship holds in the quantum theory, even if it were to be violated in classical general relativity.

T. P. Singh

1998-05-17T23:59:59.000Z

118

Ultra High Energy Cosmic Rays: origin and propagation  

E-Print Network [OSTI]

We discuss the basic difficulties in understanding the origin of the highest energy particles in the Universe - the ultrahigh energy cosmic rays (UHECR). It is difficult to imagine the sources they are accelerated in. Because of the strong attenuation of UHECR on their propagation from the sources to us these sources should be at cosmologically short distance from us but are currently not identified. We also give information of the most recent experimental results including the ones reported at this conference and compare them to models of the UHECR origin.

Todor Stanev

2007-11-14T23:59:59.000Z

119

Production of Low-Energy Cosmic-Ray Electrons  

Science Journals Connector (OSTI)

The production of cosmic-ray electrons of characteristically low energies is investigated. Secondary sources, other than that of meson decay, are considered, and constraints are placed on both secondary and primary sources. (1) Calculations are made of the intensity of low-energy knock-on and beta-decay electrons which are secondary to cosmic-ray interactions. In particular, knock-on production is calculated in the 100-KeV to 50-BeV kinetic-energy interval. Interstellar losses due to ionization, leakage from the galaxy, and synchrotron, bremsstrahlung, and inverse Compton effects are considered, as well as those due to plasma excitation, the red shift and synchrotron, bremsstrahlung, and inverse Compton effects in the intergalactic medium. The intensity of low-energy relativistic electrons from these sources is not negligible compared with the low energy ????e intensity, but it is shown not to account for the observed interplanetary electron intensity. (2) Energy inputs to the injected secondary electrons by a possible solar electric field of low magnitude and by a possible galactic Fermi acceleration are investigated. It is shown that at least one such input is necessary if the observed low-energy interplanetary electron intensity is to be attributed to secondary production alone. A heliocentric field which does allow for a fit to the low-energy data cannot, however, account for the high-energy BeV electrons found to be in excess of those from ????e production. The Fermi acceleration shown to be necessary to provide a fit is greater than that usually postulated for cosmic-ray protons, and also requires that the ratio of escape losses to acceleration ?? be much smaller than is usually assumed for protons. This distinction is acceptable only if one postulates a significant difference between interstellar proton and electron propagation. (3) The observation that the velocity spectrum of electrons in the energy-per-unit-mass region of 7-25 closely approximates that of the cosmic-ray protons, and the necessity of constraints on the secondary-electron hypothesis outlined above, suggest that most of the low-energy electrons are of primary origin. The similarity between this conclusion and the conclusion (based on the measurement of the charge ratio of electrons) that the higher energy electrons are mostly primary is discussed.

P. B. Abraham; K. A. Brunstein; T. L. Cline

1966-10-28T23:59:59.000Z

120

High energy cosmic-rays from gamma-ray burst sources: A stronger case  

E-Print Network [OSTI]

The suggested association between the sources of gamma-ray bursts (GRB's) and the sources of ultra-high energy cosmic rays (UHECR's) is based on two arguments: (i) The average energy generation rate of UHECR's is similar to the gamma-ray generation rate of GRB's, and (ii) The constraints that UHECR sources must satisfy to allow proton acceleration to >10^{20} eV are similar to those inferred for GRB sources from gamma-ray observations. We show that recent GRB and UHECR observations strengthen both arguments, and hence strengthen the suggested association.

E. Waxman

2002-10-30T23:59:59.000Z

Note: This page contains sample records for the topic "int cosmic ray" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

A simple technique for gamma ray and cosmic ray spectroscopy using plastic scintillator  

E-Print Network [OSTI]

A new and simple technique has been developed using plastic scintillator detectors for gamma ray and cosmic ray spectroscopy without single channel analyzer (SCA) or multichannel analyzer (MCA). In these experiments only a leading edge discriminator (LED) and NIM scalers have been used. Energy calibration of gamma spectra in plastic scintillators has been done using Co$^{60}$ and Cs$^{137}$ sources. The details experimental technique, analysis procedure and experimental results has been presented in this article.

Akhilesh P. Nandan; Sharmili Rudra; Himangshu Neog; S. Biswas; S. Mahapatra; B. Mohanty; P. K. Samal

2014-12-30T23:59:59.000Z

122

Ultra High Energy Cosmic Rays and Gamma Ray Bursts from Axion Stars  

E-Print Network [OSTI]

We propose a model in which ultra high energy cosmic rays and gamma ray bursts are produced by collisions between neutron stars and axion stars. The acceleration of such a cosmic ray is made by the electric field, $\\sim 10^{15} (B/10^{12} {G}) {eV} {cm}^{-1}$, which is induced in an axion star by relatively strong magnetic field $B>10^{12}$ G of a neutron star. On the other hand, similar collisions generate gamma ray bursts when magnetic field is relatively small, e.g. $\\leq 10^{10}$ G. Assuming that the axion mass is $\\sim 10^{-9}$ eV, we can explain huge energies of the gamma ray bursts $\\sim 10^{54}$ erg as well as the ultra high energies of the cosmic rays $\\sim 10^{20}$ eV. We estimate rate of energy release in the collisions and we find that the rate roughly agrees with observations. In addition, we show that these axion stars are plausible candidates for MACHOs. Since the axion star induces oscillating electric current under the magnetic field, observable monochromatic radiations are emitted.

Aiichi Iwazaki

2000-08-29T23:59:59.000Z

123

pp Interaction at Very High Energies in Cosmic Ray Experiments  

E-Print Network [OSTI]

An analysis of p-air cross section data from Extensive Air Shower (EAS) measurements is presented, based on an analytical representation of the pp scattering amplitudes that describes with high precision all available accelerator data at ISR, SPS and LHC energies. The theoretical basis of the representation, together with the very smooth energy dependence of parameters controlled by unitarity and dispersion relations, permits reliable extrapolation to high energy cosmic ray and asymptotic energy ranges. Calculations of the p-air production cross section based on Glauber formalism are made using the input values of the pp forward scattering parameters at high energies, with attention given to the independence of the real and imaginary slope parameters. The influence of contributions of diffractive intermediate states, according to Good-Walker formalism, is examined. The comparison with cosmic ray data is very satisfactory in the whole pp energy interval from 1 to 100 TeV. High energy asymptotic behavior of p-air cross sections is investigated in view of the geometric scaling property of the pp amplitudes. The observed energy dependence of the ratio between p-air and pp cross sections in the data is shown to be related to the nature of the pp cross section at high energies, that does not agree with the black disk image.

A. Kendi Kohara; Erasmo Ferreira; Takeshi Kodama

2014-06-22T23:59:59.000Z

124

Fluxes of high- and ultrahigh-energy cosmic-ray muons  

Science Journals Connector (OSTI)

The positive excess of cosmic-ray muons at energies higher than 1 TeV is estimated taking ... particle and antiparticles in proton-proton interactions at energies of ?20 TeV. The fluxes of cosmic-ray muons at energies

L. V. Volkova

2007-04-01T23:59:59.000Z

125

28th International Cosmic Ray Conference 3901 Effective Energy of Neutron Monitors  

E-Print Network [OSTI]

28th International Cosmic Ray Conference 3901 Effective Energy of Neutron Monitors K. Alanko,1 I of the neutron monitor energy range is not well defined. Also, the median energy of a neutron monitor varies in the course of the solar cycle. Here we present a new concept of the effective energy of cosmic rays measured

Usoskin, Ilya G.

126

Report of the 2006 External Review Committee for the Institute for Cosmic Ray Research2006  

E-Print Network [OSTI]

20106 URL Report of the 2006 External Review Committee for the Institute for Cosmic Ray Research2006 2000-2005 2007 http://www.icrr.u-tokyo.ac.jp/report/index.html Scientific Activities() 2000-2005 2006 http://www.icrr.u-tokyo.ac.jp/report/index.html (The Review of Institute for Cosmic Ray Research

Miyashita, Yasushi

127

Neutron production by cosmic-ray muons at shallow depth J. Busenitz,1  

E-Print Network [OSTI]

Neutron production by cosmic-ray muons at shallow depth F. Boehm,3 J. Busenitz,1 B. Cook,3 G Received 23 June 2000; published 12 October 2000 The yield of neutrons produced by cosmic ray muons of one and two neutron captures was determined. Modeling the neutron capture efficiency allowed us

Piepke, Andreas G.

128

Correlation of the highest energy cosmic rays with nearby extragalactic objects  

E-Print Network [OSTI]

Correlation of the highest energy cosmic rays with nearby extragalactic objects The Pierre Auger Collaboration Observatorio Pierre Auger, Avenida San Mart´in Norte 304, (5613) Malarg¨ue, Mendoza, Argentina a correlation between the arrival directions of cosmic rays with energy above 6 ? 1019 electron volts

129

A Bayesian analysis of the 27 highest energy cosmic rays detected by the Pierre Auger Observatory  

Science Journals Connector (OSTI)

......analysis of the 27 highest energy cosmic rays detected by the...is possible that ultrahigh energy cosmic rays (UHECRs) are...is located near Malargue in Argentina, at a longitude of 69.4...UHECRs with reliable detected energies of E obsE min = 5.7 1019......

Laura J. Watson; Daniel J. Mortlock; Andrew H. Jaffe

2011-11-21T23:59:59.000Z

130

Why are we still studying cosmic rays? Pierre Auger Observatory: past, present, future  

E-Print Network [OSTI]

Energy Cosmic Rays Using Two Large Air Shower Detectors Mendoza, Argentina (construction underway - 1932 Jakarta Genoa Auger and LePrince-Ringuet sailed between Le Havre and Argentina in 1933 Cosmic Rays are charged particles, the nuclei of atoms. Like the drunken man's walk! BUT the highest energy particles

131

Energy Spectrum of Ultrahigh Energy Cosmic Rays with ExtraGalactic Origin  

E-Print Network [OSTI]

Energy Spectrum of Ultra­high Energy Cosmic Rays with Extra­Galactic Origin Shigeru YOSHIDA for the propagation of ultra­high energy cosmic ray nucleons in the intergalactic space by a Monte­Carlo method. The resulting energy spectrum above 10 18 eV is modified by the interaction of nucleons with the micro wave

Yoshida, Shigeru

132

17 March 2009 Do some ultra-high-energy cosmic rays originate in  

E-Print Network [OSTI]

17 March 2009 Do some ultra-high-energy cosmic rays originate in higher-dimensional space-time? Abstract I speculate that some ultra-high-energy cosmic rays may originate in another universe in flat (non have needed an initial energy of 500 EeV to arrive at earth with 320 EeV. If it originated farther out

Bryan, Ronald

133

History of cosmic ray research in Finland I.G. Usoskin a,*, E. Valtonen b  

E-Print Network [OSTI]

History of cosmic ray research in Finland I.G. Usoskin a,*, E. Valtonen b , R. Vainio c , P The history of cosmic ray research in Finland can be traced back to the end of 1950s, when first ground on-line database in Oulu and a new muon measuring underground site in Pyha¨salmi. Research groups

Usoskin, Ilya G.

134

Gamma Ray Bursts: recent results and connections to very high energy Cosmic Rays and Neutrinos  

E-Print Network [OSTI]

Gamma-ray bursts are the most concentrated explosions in the Universe. They have been detected electromagnetically at energies up to tens of GeV, and it is suspected that they could be active at least up to TeV energies. It is also speculated that they could emit cosmic rays and neutrinos at energies reaching up to the $10^{18}-10^{20}$ eV range. Here we review the recent developments in the photon phenomenology in the light of \\swift and \\fermi satellite observations, as well as recent IceCube upper limits on their neutrino luminosity. We discuss some of the theoretical models developed to explain these observations and their possible contribution to a very high energy cosmic ray and neutrino background.

Pter Mszros; Katsuaki Asano; Pter Veres

2012-09-11T23:59:59.000Z

135

New Precision in Cosmic Ray Measurements; Yielding Extension of Spectrum and Indications of Bands  

Science Journals Connector (OSTI)

Method of measurement of capacities of the order of one cm.A method is described which leads to greatly increased precision in the measurement of capacities of the order of one electrostatic unit.More penetrating cosmic rays than we have previously found are indicated by a new absorption curve obtained in Gem Lake (9080 ft.) and Lake Arrowhead (5125 ft.) with much greater precision than hitherto possible.Cosmic-ray spectrum.The new curve affords definite evidence for the existence of bands in the spectrum of cosmic rays. The measurements indicate that the cosmic rays consist chiefly of two bands about three octaves apart of mean absorption coefficients 0.35 and 0.04 to 0.05 per meter of water.The total energy of cosmic rays at the top of the atmosphere is found to be very nearly one-tenth that due to starlight and heat as computed from Seares' data.

R. A. Millikan and G. H. Cameron

1928-06-01T23:59:59.000Z

136

Measurement of Cosmic Ray Flux in China JinPing underground Laboratory  

E-Print Network [OSTI]

China JinPing underground Laboratory (CJPL) is the deepest underground laboratory presently running in the world. In such a deep underground laboratory, the cosmic ray flux is a very important and necessary parameter for rare event experiments. A plastic scintillator telescope system has been set up to measure the cosmic ray flux. The performance of the telescope system has been studied using the cosmic ray on the ground laboratory near CJPL. Based on the underground experimental data taken from November 2010 to December 2011 in CJPL, which has effective live time of 171 days, the cosmic ray muon flux in CJPL is measured to be (2.0+-0.4)*10^(-10)/(cm^2)/(s). The ultra-low cosmic ray background guarantees CJPL's ideal environment for dark matter experiment.

Wu, Yu-Cheng; Yue, Qian; LI, Yuan-Jing; Cheng, Jian-Ping; Kang, Ke-Jun; Chen, Yun-Hua; Li, Jin; Li, Jian-Min; Li, Yu-Lan; Liu, Shu-Kui; Ma, Hao; Ren, Jin-Bao; Shen, Man-Bin; Wang, Ji-Min; Wu, Shi-Yong; Xue, Tao; YI, Nan; Zeng, Xiong-Hui; Zeng, Zhi; Zhu, Zhong-Hua

2013-01-01T23:59:59.000Z

137

Measurement of cosmic ray flux in the China JinPing underground laboratory  

Science Journals Connector (OSTI)

The China JinPing underground Laboratory (CJPL) is the deepest underground laboratory running in the world at present. In such a deep underground laboratory, the cosmic ray flux is a very important and necessary parameter for rare-event experiments. A plastic scintillator telescope system has been set up to measure the cosmic ray flux. The performance of the telescope system has been studied using the cosmic rays on the ground laboratory near the CJPL. Based on the underground experimental data taken from November 2010 to December 2011 in the CJPL, which has an effective live time of 171 days, the cosmic ray muon flux in the CJPL is measured to be (2.00.4)?10?10/(cm2s). The ultra-low cosmic ray background guarantees an ideal environment for dark matter experiments at the CJPL.

Wu Yu-Cheng (???); Hao Xi-Qing (???); Yue Qian (??); Li Yuan-Jing (???); Cheng Jian-Ping (???); Kang Ke-Jun (???); Chen Yun-Hua (???); Li Jin (??); Li Jian-Min (???); Li Yu-Lan (???); Liu Shu-Kui (???); Ma Hao (??); Ren Jin-Bao (???); Shen Man-Bin (???); Wang Ji-Min (???); Wu Shi-Yong (???); Xue Tao (??); Yi Nan (??); Zeng Xiong-Hui (???); Zeng Zhi (??); Zhu Zhong-Hua (???)

2013-01-01T23:59:59.000Z

138

Cosmic Ray Origin: Lessons from Ultra-High-Energy Cosmic Rays and the Galactic/Extragalactic Transition  

E-Print Network [OSTI]

We examine the question of the origin of the Galactic cosmic-rays (GCRs) in the light of the data available at the highest energy end of the spectrum. We argue that the data of the Pierre Auger Observatory and of the KASCADE-Grande experiment suggest that the transition between the Galactic and the extragalactic components takes place at the energy of the ankle in the all-particle cosmic-ray spectrum, and at an energy of the order of $10^{17}$ eV for protons. Such a high energy for Galactic protons appears difficult to reconcile with the general view that GCRs are accelerated by the standard diffusive shock acceleration process at the forward shock of individual supernova remnants (SNRs). We also review various difficulties of the standard SNR-GCR connection, related to the evolution of the light element abundances and to significant isotopic anomalies. We point out that most of the power injected by the supernovae in the Galaxy is actually released inside superbubbles, which may thus play an important role i...

Parizot, Etienne

2014-01-01T23:59:59.000Z

139

Cosmological Gamma-Ray Bursts and the Highest Energy Cosmic Rays  

Science Journals Connector (OSTI)

We discuss a scenario in which the highest energy cosmic rays (CR's) and cosmological ?-ray bursts (GRB's) have a common origin. This scenario is consistent with the observed CR flux above 1020 eV, provided that each burst produces similar energies in ? rays and in CR's above 1020 eV. Protons may be accelerated by Fermi's mechanism to energies ?1020 eV in a dissipative, ultrarelativistic wind, with luminosity and Lorentz factor high enough to produce a GRB. For a homogeneous GRB distribution, this scenario predicts an isotropic, time-independent CR flux.

Eli Waxman

1995-07-17T23:59:59.000Z

140

SUPERNOVA REMNANT KES 17: AN EFFICIENT COSMIC RAY ACCELERATOR INSIDE A MOLECULAR CLOUD  

SciTech Connect (OSTI)

The supernova remnant Kes 17 (SNR G304.6+0.1) is one of a few but growing number of remnants detected across the electromagnetic spectrum. In this paper, we analyze recent radio, X-ray, and ?-ray observations of this object, determining that efficient cosmic ray acceleration is required to explain its broadband non-thermal spectrum. These observations also suggest that Kes 17 is expanding inside a molecular cloud, though our determination of its age depends on whether thermal conduction or clump evaporation is primarily responsible for its center-filled thermal X-ray morphology. Evidence for efficient cosmic ray acceleration in Kes 17 supports recent theoretical work concluding that the strong magnetic field, turbulence, and clumpy nature of molecular clouds enhance cosmic ray production in supernova remnants. While additional observations are needed to confirm this interpretation, further study of Kes 17 is important for understanding how cosmic rays are accelerated in supernova remnants.

Gelfand, Joseph D. [NYU Abu Dhabi, P.O. Box 903, New York, NY 10276 (United States); Castro, Daniel [MIT Kavli Institute for Astrophysics and Space Research, 77 Massachusetts Avenue 37-241, Cambridge, MA 02139 (United States); Slane, Patrick O. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Temim, Tea [Observational Cosmology Lab, Code 665, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Hughes, John P. [Department of Physics and Astronomy Rutgers University 136 Frelinghuysen Road, Piscataway, NJ 08854 (United States); Rakowski, Cara, E-mail: jg168@cosmo.nyu.edu, E-mail: cara.rakowski@gmail.com [United States Patent and Trademark Office, 600 Dulany Street, Alexandria, VA (United States)

2013-11-10T23:59:59.000Z

Note: This page contains sample records for the topic "int cosmic ray" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Possible association of ultra-high-energy cosmic-ray events with strong gamma-ray bursts  

E-Print Network [OSTI]

We point out that each of the error boxes of the two highest-energy cosmic-ray shower events known, overlaps with that of a strong gamma-ray burst (GRB). The GRBs precede the cosmic rays by 5.5, and 11 months respectively. In one case the strongest known cosmic ray is paired with the strongest gamma-ray burst in the BATSE catalogue. The probability of this to have occurred by chance seems rather small. Without building on post-factum statistics, we think the above is remarkable enough to suggest that the cosmic ray and gamma-ray burst were produced by the same outburst. A time delay (and a small positional disparity) is expected, since the trajectory of a charged cosmic-ray particle is wriggled by intervening magnetic fields. We estimate that the Galaxy's field alone may produce a delay of the order observed. We discuss some of the implications that follow if such an association is confirmed. For example, the upper limit on the distance to the cosmic-ray source, combined with a much-better-determined position of the gamma-ray burst source, narrows greatly the volume in which to look for an optical counterpart. There is also useful information in the time delay regarding, e.g., intergalactic magnetic fields.

Mordehai Milgrom; Vladimir Usov

1995-05-03T23:59:59.000Z

142

arXiv:astro-ph/0303484v121Mar2003 Conceptual Design of a Cosmic Ray Detector Operating  

E-Print Network [OSTI]

York, USA July 8, 2004 Abstract For our understanding of the origin of ultra high energy cosmic rays evidence that at these energies, the origin of cosmic rays changes from predominantly Galactic offers, this study will provide crucial information on the origin of ultra high energy cosmic rays

143

THE HIGHEST-ENERGY COSMIC RAYS What in the cosmos can possibly be accelerating protons to 1020  

E-Print Network [OSTI]

the implications of the energy spectrum measurements on our understanding of the origin of cosmic rays, and we of origin Below 1015 eV the cosmic-ray energy spectrum obeys an approximate power law, falling like E-2THE HIGHEST-ENERGY COSMIC RAYS What in the cosmos can possibly be accelerating protons to 1020

144

Electromagnetic Interactions of High-Energy Cosmic-Ray Muons  

Science Journals Connector (OSTI)

The electromagnetic interactions of cosmic-ray muons in the energy range up to 1 TeV were investigated with a spark-chamber calorimeter in combination with the Kiel spectrograph. The purpose was to investigate the different kinds of electromagnetic processes (knock-on, direct-pair, bremsstrahlung, and multiple pion production) in the range of energy transfer from 0.2 to 100 GeV. The production of pions is in reasonable agreement with the theoretical prediction of Daiyasu et al. In the region of high energy transfer (>2 Gev) the experimental results agree with Bhabha's theory of the knock-on process as well as with Murota's theory of direct pair production. However, in the region of energy transfer around 1 GeV there are minor deviations from these theories, in contradiction with accelerator data.

O. C. Allkofer, C. Grupen, and W. Stamm

1971-08-01T23:59:59.000Z

145

Heavy Cosmic Ray Nuclei from Extragalactic Sources above 'The Ankle'  

E-Print Network [OSTI]

A very recent observation by the Auger Observatory group claims strong evidence for cosmic rays above 56 EeV being protons from Active Galactic Nuclei. If, as would be expected, the particles above the ankle at about 2 EeV are almost all of extragalactic origin then it follows that the characteristics of the nuclear interactions of such particles would need to be very different from conventional expectation -- a result that follows from the measured positions of 'shower maximum' in the Auger' work. Our own analysis gives a different result, viz that the detected particles are still 'massive' specifically with a mean value of = 2.2 +- 0.8. The need for a dramatic change in the nuclear physics disappears.

Tadeusz Wibig; Arnold W. Wolfendale

2007-12-20T23:59:59.000Z

146

Cosmic Rays from the Ankle to the Cut-Off  

E-Print Network [OSTI]

Recent advances in measuring and interpreting cosmic rays from the spectral ankle to the highest energies are briefly reviewed. The prime question at the highest energies is about the origin of the flux suppression observed at E ~ 4x10^{19} eV. Is this the long awaited GZK-effect or the exhaustion of sources? The key to answering this question will be provided by the largely unknown mass composition at the highest energies. The high level of isotropy observed even at the highest energies challenges models of a proton dominated composition if extragalactic magnetic fields are on the order of a few nG or less. We shall discuss the experimental and theoretical progress in the field and the prospects for the next decade.

Kampert, Karl-Heinz

2014-01-01T23:59:59.000Z

147

Heavy Cosmic Ray Nuclei from Extragalactic Sources above 'The Ankle'  

E-Print Network [OSTI]

A very recent observation by the Auger Observatory group claims strong evidence for cosmic rays above 56 EeV being protons from Active Galactic Nuclei. If, as would be expected, the particles above the ankle at about 2 EeV are almost all of extragalactic origin then it follows that the characteristics of the nuclear interactions of such particles would need to be very different from conventional expectation -- a result that follows from the measured positions of 'shower maximum' in the Auger' work. Our own analysis gives a different result, viz that the detected particles are still 'massive' specifically with a mean value of = 2.2 +- 0.8. The need for a dramatic change in the nuclear physics disappears.

Wibig, Tadeusz

2007-01-01T23:59:59.000Z

148

Characterising encapsulated nuclear waste using cosmic-ray muon tomography  

E-Print Network [OSTI]

Tomographic imaging techniques using the Coulomb scattering of cosmic-ray muons have been shown previously to successfully identify and characterise low- and high-Z materials within an air matrix using a prototype scintillating-fibre tracker system. Those studies were performed as the first in a series to assess the feasibility of this technology and image reconstruction techniques in characterising the potential high-Z contents of legacy nuclear waste containers for the UK Nuclear Industry. The present work continues the feasibility study and presents the first images reconstructed from experimental data collected using this small-scale prototype system of low- and high-Z materials encapsulated within a concrete-filled stainless-steel container. Clear discrimination is observed between the thick steel casing, the concrete matrix and the sample materials assayed. These reconstructed objects are presented and discussed in detail alongside the implications for future industrial scenarios.

Anthony Clarkson; David J. Hamilton; Matthias Hoek; David G. Ireland; John R. Johnstone; Ralf Kaiser; Tibor Keri; Scott Lumsden; David F. Mahon; Bryan McKinnon; Morgan Murray; Sin Nutbeam-Tuffs; Craig Shearer; Guangliang Yang; Colin Zimmerman

2014-10-27T23:59:59.000Z

149

Characterising encapsulated nuclear waste using cosmic-ray muon tomography  

E-Print Network [OSTI]

Tomographic imaging techniques using the Coulomb scattering of cosmic-ray muons have been shown previously to successfully identify and characterise low- and high-Z materials within an air matrix using a prototype scintillating-fibre tracker system. Those studies were performed as the first in a series to assess the feasibility of this technology and image reconstruction techniques in characterising the potential high-Z contents of legacy nuclear waste containers for the UK Nuclear Industry. The present work continues the feasibility study and presents the first images reconstructed from experimental data collected using this small-scale prototype system of low- and high-Z materials encapsulated within a concrete-filled stainless-steel container. Clear discrimination is observed between the thick steel casing, the concrete matrix and the sample materials assayed. These reconstructed objects are presented and discussed in detail alongside the implications for future industrial scenarios.

Clarkson, Anthony; Hoek, Matthias; Ireland, David G; Johnstone, John R; Kaiser, Ralf; Keri, Tibor; Lumsden, Scott; Mahon, David F; McKinnon, Bryan; Murray, Morgan; Nutbeam-Tuffs, Sin; Shearer, Craig; Yang, Guangliang; Zimmerman, Colin

2014-01-01T23:59:59.000Z

150

A Cosmic Ray Measurement Facility for ATLAS Muon Chambers  

E-Print Network [OSTI]

Monitored Drift Tube (MDT) chambers will constitute the large majority of precision detectors in the Muon Spectrometer of the ATLAS experiment at the Large Hadron Collider at CERN. For commissioning and calibration of MDT chambers, a Cosmic Ray Measurement Facility is in operation at Munich University. The objectives of this facility are to test the chambers and on-chamber electronics, to map the positions of the anode wires within the chambers with the precision needed for standalone muon momentum measurement in ATLAS, and to gain experience in the operation of the chambers and on-line calibration procedures. Until the start of muon chamber installation in ATLAS, 88 chambers built at the Max Planck Institute for Physics in Munich have to be commissioned and calibrated. With a data taking period of one day individual wire positions can be measured with an accuracy of 8.3 micrometers in the chamber plane and 27 micrometers in the direction perpendicular to that plane.

O. Biebel; M. Binder; M. Boutemeur; A. Brandt; J. Dubbert; G. Duckeck; J. Elmsheuser; F. Fiedler; R. Hertenberger; O. Kortner; T. Nunnemann; F. Rauscher; D. Schaile; P. Schieferdecker; A. Staude; W. Stiller; R. Stroehmer; R. Vertesi

2003-07-30T23:59:59.000Z

151

COSMIC RAY MODULATION BEYOND THE HELIOPAUSE: A HYBRID MODELING APPROACH  

SciTech Connect (OSTI)

Results from a newly developed hybrid cosmic ray (CR) modulation model are presented. In this approach, the transport of CRs is computed by incorporating the plasma flow from a magnetohydrodynamic model for the heliospheric environment, resulting in representative CR transport. The model is applied to the modulation of CRs beyond the heliopause (HP) and we show that (1) CR modulation persists beyond the HP, so it is unlikely that the Voyager spacecraft will measure the pristine local interstellar spectra of galactic CRs when crossing the HP. (2) CR modulation in the outer heliosheath could maintain solar-cycle-related changes. (3) The modulation of CRs in the outer heliosheath is primarily determined by the ratio of perpendicular to parallel diffusion, so that the value of the individual diffusion coefficients cannot be determined uniquely using this approach. (4) CRs can efficiently diffuse between the nose and tail regions of the heliosphere.

Strauss, R. D.; Potgieter, M. S.; Ferreira, S. E. S. [Centre for Space Research, North-West University, Potchefstroom Campus, Private Bag X6001, Potchefstroom 2520 (South Africa); Fichtner, H.; Scherer, K., E-mail: dutoit.strauss@nwu.ac.za [Institut fuer Theoretische Physik, Lehrstuhl IV: Weltraum- und Astrophysik, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany)

2013-03-01T23:59:59.000Z

152

Spatial Intensity Profiles of Galactic Cosmic Rays in the Heliosphere  

SciTech Connect (OSTI)

We study the spatial intensity profiles of galactic cosmic ray protons (H) and {alpha}-particles (He) during the solar minimum periods of 1987 (the so-called negative drift state) and 1977/1997 (both positive drift states) of the heliosphere. These intensities were measured with the Pioneer, Voyager and IMP spacecraft. The 1997 intensities were so low that one cannot readily explain them, even with the acceleration at the solar wind termination shock (SWTS) and modulation in the heliosheath included. Our heliospheric model is azimuthally symmetric with a spherical shock and heliopause, however, and we infer from its results that more realistic geometries may produce modulation effects that will explain the observations better.

Moraal, H. [School of Physics, Northwest University, Potchefstroom 2520 (South Africa); Caballero-Lopez, R.A.; McDonald, F.B. [Institute for Physical Science and Technology, University of Maryland, College Park, MD 20740 (United States)

2004-09-15T23:59:59.000Z

153

Cosmic-ray electron signatures of dark matter  

SciTech Connect (OSTI)

There is evidence for an excess in cosmic-ray electrons at about 500 GeV energy, that may be related to dark-matter annihilation. I have calculated the expected electron contributions from a pulsar and from Kaluza-Klein dark matter, based on a realistic treatment of the electron propagation in the Galaxy. Pulsars younger than about 10{sup 5} years naturally cause a narrow peak at a few hundred GeV in the locally observed electron spectrum, similar to that observed. On the other hand, if electron production by dark matter is predominantly occurring in high-mass clumps (> or approx. 10{sup 3}M{sub {center_dot}}), the sharp cutoff in the contribution from Kaluza-Klein particles is sometimes more pronounced, but often smoothed out and indistinguishable from a pulsar source, and therefore the spectral shape of the electron excess is insufficient to discriminate a dark-matter origin from more conventional astrophysical explanations.

Pohl, Martin [Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States)

2009-02-15T23:59:59.000Z

154

A Model of the Cosmic Ray Induced Atmospheric Neutron Environment  

E-Print Network [OSTI]

In order to optimise the design of space instruments making use of detection materials with low atomic numbers, an understanding of the atmospheric neutron environment and its dependencies on time and position is needed. To produce a simple equation based model, Monte Carlo simulations were performed to obtain the atmospheric neutron fluxes produced by charged galactic cosmic ray interactions with the atmosphere. Based on the simulation results the omnidirectional neutron environment was parametrised including dependencies on altitude, magnetic latitude and solar activity. The upward- and downward-moving component of the atmospheric neutron flux are considered separately. The energy spectra calculated using these equations were found to be in good agreement with data from a purpose built balloon-borne neutron detector, high altitude aircraft data and previously published simulation based spectra.

Kole, Merlin; Salinas, Maria Muoz

2014-01-01T23:59:59.000Z

155

NONTHERMAL RADIATION FROM COSMIC-RAY MODIFIED SHOCKS  

SciTech Connect (OSTI)

We calculate nonthermal radiation from cosmic-ray (CR) protons and electrons accelerated at CR modified plane and spherical shocks, using time-dependent, diffusive shock acceleration (DSA) simulations that include radiative losses of CR electrons. Strong non-relativistic shocks with physical parameters relevant for young supernova remnants (SNRs) are considered in both the plane-parallel and spherically symmetric geometries, and compared at times when their dynamical and CR properties are concordant. A thermal leakage injection model and a Bohm-like diffusion coefficient are adopted. After DSA energy gains balance radiative losses, the electron spectrum at the plane shock approaches a time-asymptotic spectrum with a super-exponential cutoff above the equilibrium momentum. The postshock electron spectrum cuts off at a progressively lower momentum downstream from the shock due to the energy losses. That results in the steepening of the volume integrated electron energy spectrum by one power of the particle energy. These features evolve toward lower energies in the spherical, SNR shocks. In a CR modified shock, pion decay gamma-ray emission reveals distinct signatures of nonlinear DSA due to the concave proton momentum spectrum. Although the electron momentum spectrum has a much weaker concavity, the synchrotron spectral slope at the shock may flatten by about 0.1-0.3 between radio and X-ray bands. The slope of the volume integrated emission spectrum behaves nonlinearly around the break frequency.

Kang, Hyesung [Department of Earth Sciences, Pusan National University, Pusan 609-735 (Korea, Republic of); Edmon, Paul P. [Department of Physics and Astronomy, University of Manitoba, Winnipeg, MB R3T 2N2 (Canada); Jones, T. W., E-mail: kang@uju.es.pusan.ac.kr, E-mail: pedmon@physics.umanitoba.ca, E-mail: twj@msi.umn.edu [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)

2012-02-01T23:59:59.000Z

156

Neutrino Astronomy and Cosmic Rays Spectroscopy at Horizons  

E-Print Network [OSTI]

A new air-showering physics may rise in next years at horizon, offering at different angles and altitudes a fine tuned filtered Cosmic Rays astrophysics and an upward Neutrino induced air-showering astronomy. Most of this opportunity arises because of neutrino masses, their mixing and the consequent replenishment of rarest tau flavor during its flight in Space. Horizontal air atmosphere act as a filter for High energy Cosmic Rays (CR) and as a beam dump for Ultra High Energy (UHE) neutrinos and a powerfull amplifier for its tau decay in air by its wide showering areas. Earth sharp shadows plays the role of a huge detector volume for UHE neutrino and a noise-free screen for upcoming EeVs tau air-showers (as well PeVs anti-neutrino electron air interactions). Projects for Tau Airshowers are growing at the top of a mountains or at the edge of a cliff. ASHRA in Hawaii and CRNTN in Utah are tracking fluorescence lights, while other novel projects on Crown array detectors on mountains, on balloons and satellites are elaborated for Cherenkov lights. AUGER, facing the Ande edges, ARGO located within a deep valley are testing inclined showers; MILAGRO (and MILAGRITO) may be triggered by horizontal up-going muon bundles from the Earth edges; HIRES and AUGER UHECR detectors, linking twin array telescopes along their axis may test horizontal Cerenkov blazing photons. MAGIC (Hess, Veritas) and Shalon Telescopes may act already like a detector for few PeVs and Glashow resonance neutrino events; MAGIC pointing downward to terrestrial ground acts as a massive tens of km^3 detector, making it the most sensitive dedicated neutrino telescope. MAGIC facing the sea edges must reveal mirrored downward UHECR Air-showers Cherenkov flashes. Magic-crown systems may lead to tens km^3, neutrino detectors.

D. Fargion

2006-04-20T23:59:59.000Z

157

Space-Based Cosmic-Ray and Gamma-Ray Detectors: a Review  

E-Print Network [OSTI]

Prepared for the 2014 ISAPP summer school, this review is focused on space-borne and balloon-borne cosmic-ray and gamma-ray detectors. It is meant to introduce the fundamental concepts necessary to understand the instrument performance metrics, how they tie to the design choices and how they can be effectively used in sensitivity studies. While the write-up does not aim at being complete or exhaustive, it is largely self-contained in that related topics such as the basic physical processes governing the interaction of radiation with matter and the near-Earth environment are briefly reviewed.

Baldini, Luca

2014-01-01T23:59:59.000Z

158

A new method for imaging nuclear threats using cosmic ray muons  

E-Print Network [OSTI]

Muon tomography is a technique that uses cosmic ray muons to generate three dimensional images of volumes using information contained in the Coulomb scattering of the muons. Advantages of this technique are the ability of cosmic rays to penetrate significant overburden and the absence of any additional dose delivered to subjects under study above the natural cosmic ray flux. Disadvantages include the relatively long exposure times and poor position resolution and complex algorithms needed for reconstruction. Here we demonstrate a new method for obtaining improved position resolution and statistical precision for objects with spherical symmetry.

Morris, C L; Borozdin, Konstantin; Miyadera, Haruo; Perry, John; Rose, Evan; Watson, Scott; White, Timothy; Aberle, Derek; Green, J Andrew; McDuff, George G; Luki?, Zarija; Milner, Edward C

2013-01-01T23:59:59.000Z

159

ON COSMIC RAY MODULATION BEYOND THE HELIOPAUSE: WHERE IS THE MODULATION BOUNDARY?  

SciTech Connect (OSTI)

Two of the paradigms in modeling the transport of galactic cosmic rays are that the modulation boundary is the heliopause and that the local interstellar spectra are identical to the galactic cosmic ray spectra. Here we demonstrate that the proton spectrum is already modulated due to an altered interstellar diffusion in the outer heliosheath as a consequence of the heliospheric 'obstacle' in the interstellar flow. The main modulation effect however is adiabatic energy losses during a 'confinement time' of cosmic rays inside the heliosphere.

Scherer, K.; Fichtner, H. [Institut fuer Theoretische Physik IV, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany); Strauss, R. D.; Ferreira, S. E. S.; Potgieter, M. S. [Centre for Space Research, North-West University, 2520 Potchefstroom (South Africa); Fahr, H.-J. [Argelander Institute, Universitaet of Bonn, D-53121 Bonn (Germany)

2011-07-10T23:59:59.000Z

160

X-ray imaging, spacecraft nuclear fission and cosmic ray contraband  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

R&D 100 Awards winners R&D 100 Awards winners X-ray imaging, spacecraft nuclear fission and cosmic ray contraband detection score R&D 100 awards R&D Magazine announced the winners and three technologies from Los Alamos National Laboratory and its partners are among the honorees. July 8, 2013 MiniMAX is a battery powered, digital x-ray imaging system that is completely self-contained, lightweight, compact and portable. MiniMAX is a battery powered, digital x-ray imaging system that is completely self-contained, lightweight, compact and portable. Contact Nancy Ambrosiano Communications Office (505) 667-0471 Email "The innovation and creativity shown in this year's awards is truly inspiring. It gives me great confidence in the Laboratory's intellectual vitality and ongoing role in national security science. Congratulations to

Note: This page contains sample records for the topic "int cosmic ray" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Earth Planets Space, 62, 333345, 2010 Cosmic ray and solar energetic particle flux in paleomagnetospheres  

E-Print Network [OSTI]

Earth Planets Space, 62, 333­345, 2010 Cosmic ray and solar energetic particle flux of the shield prohibiting energetic particles of solar and cosmic origin directly hitting the Earth surface particles. 1. Introduction Planet Earth possesses a global magnetic field since at least 3.2 billion years

Steinhoff, Heinz-Jürgen

162

An Electromagnetic Calorimeter for Spectroscopy of TeV Cosmic Rays Muons  

Science Journals Connector (OSTI)

In principle, the energy of muons from cosmic rays can be deduced from the frequency and the energy of secondary showers, produced by the muons in thick absorber layers. The main interaction processes of high-energy

I. M. Brncu?; H. J. Mathes; J. Wentz; H. Bozdog

1994-01-01T23:59:59.000Z

163

Temperature effect of the integral flux of cosmic-ray muons at high energies  

Science Journals Connector (OSTI)

The temperature coefficients of the integral fluxes of cosmic-ray muons arriving at sea level vertically and horizontally with energies of 102, 104, and 3 106...GeV are calculated. Decays of pions, kaons, and c...

L. V. Volkova

2013-11-01T23:59:59.000Z

164

High-energy hadrons and cosmic-ray muons in the atmosphere  

Science Journals Connector (OSTI)

The experimental data on fluxes of high-energy hadrons and muons in the atmosphere are compared with the ... the latest information about the properties of high-energy interactions and the primary cosmic-ray comp...

J. Kempa; J. Wdowczyk

165

Fluxes of cosmic-ray muons and atmospheric neutrinos at high energies  

Science Journals Connector (OSTI)

The problem of charm generation in the interactions of nucleons with nuclei of air atoms at energies inaccessible at present-day accelerators is discussed. Both experimental data on cosmic-ray muons and the predi...

L. V. Volkova; G. T. Zatsepin

2001-02-01T23:59:59.000Z

166

Energy spectrum of cosmic ray muons above 10 TeV according to BUST data  

Science Journals Connector (OSTI)

The energy spectrum of cosmic ray muons in the range of several TeV to ... obtained through the analysis of multiple interactions of muons (the pair meter technique) in the ... are compared with prior BUST data o...

A. G. Bogdanov; R. P. Kokoulin

2011-03-01T23:59:59.000Z

167

Bremsstrahlung photons from cosmic ray muons of high and ultrahigh energies  

Science Journals Connector (OSTI)

The results from calculations for fluxes of bremsstrahlung photons generated at different depths in the atmosphere by cosmic ray muons with energies of up to 1010 GeV are presented. It is shown that the generatio...

L. V. Volkova

2011-03-01T23:59:59.000Z

168

28th International Cosmic Ray Conference 357 The Angular Reconstruction and Angular Resolution of Air  

E-Print Network [OSTI]

304, (5613) Malargue, Argentina Abstract The origin of the highest energy cosmic rays con- struction in Malargue, Argentina. It was designed to be fully efficient for showers of energy

169

Short-period variation of cosmic-ray intensity observed in the stratosphere  

Science Journals Connector (OSTI)

To investigate the variation of the cosmic-ray intensity in the Earth atmosphere, stratospheric balloon soundings are performed weekly at Campinas (Brazil...2 and 173 g/cm2. Apparently these oscillations are not ...

N. A. Van Bui; I. M. Martin; A. Turtelli jr.; Yu. I. Stozhkov

170

THE INTERPLANETARY NETWORK SUPPLEMENT TO THE BATSE CATALOGS OF UNTRIGGERED COSMIC GAMMA-RAY BURSTS  

E-Print Network [OSTI]

THE INTERPLANETARY NETWORK SUPPLEMENT TO THE BATSE CATALOGS OF UNTRIGGERED COSMIC GAMMA-RAY BURSTS gamma-ray bursts (GRBs) observed as untriggered events by the Burst and Transient Source Experiment to detect BATSE un- triggered bursts. Subject headinggs: catalogs -- gamma rays: bursts Online material

California at Berkeley, University of

171

The Interplanetary Network Supplement to the BATSE 5B Catalog of Cosmic Gamma-Ray Bursts  

E-Print Network [OSTI]

The Interplanetary Network Supplement to the BATSE 5B Catalog of Cosmic Gamma-Ray Bursts K. Hurley Interplanetary Network (IPN) localization information for 343 gamma-ray bursts observed by the Burst Gamma-Ray Observatory (CGRO) mission, obtained by analyzing the arrival times of these bursts

California at Berkeley, University of

172

Gamma-ray bursts: cosmic rulers for the high-redshift universe?  

Science Journals Connector (OSTI)

...research-article Discussion Meeting Issue Gamma-ray bursts organized by Alan Wells, Ralph...J. Wijers and Martin Rees Gamma-ray bursts: cosmic rulers for the high-redshift...into spectral correlations in gamma-ray bursts (GBRs), in the hope that...

2007-01-01T23:59:59.000Z

173

Cosmic-ray Muon Radiography of a Volcano Seismo Seminor at Caltech, Nov 5, 2004  

E-Print Network [OSTI]

of the high-energy cosmic-ray muons passing through a mountain. This technique is in principle, based upon) with a mean energy of a few GeV (109 eV). Such high-energy muons have been used to explore the internal. It is also known that horizontally arriving cosmic-ray muons have a strong intensity in the high energy

Heaton, Thomas H.

174

Pierre Auger Enhancements: Transition from Galactic to Extragalactic Cosmic Ray Sources  

SciTech Connect (OSTI)

The Pierre Auger Collaboration has decided to include detector enhancements in order to have unitary detection efficiencies down to 1017 eV in cosmic rays detection. These enhancements consist in high elevation telescopes and an infill area with both surface detectors and underground muon counters thus allowing a detailed study of the spectrum region where the cosmic rays sources are assumed to change from galactic to extragalactic origins.

Etchegoyen, A. [Laboratorio Tandar - Comision Nacional de Energia Atomica, Buenos Aires (Argentina); Universidad Tecnologica Nacional, Regional Buenos Aires, Buenos Aires (Argentina); Melo, D.; Supanitsky, A. D. [Laboratorio Tandar - Comision Nacional de Energia Atomica, Buenos Aires (Argentina); Medina, M. C. [Laboratorio Tandar - Comision Nacional de Energia Atomica, Buenos Aires (Argentina); CONICET. Buenos Aires (Argentina)

2007-06-19T23:59:59.000Z

175

Temporal and energy behavior of cosmic ray fluxes in the periods of low solar activity  

E-Print Network [OSTI]

Modulation of galactic cosmic ray intensity is governed by several mechanisms including diffusion, convection, adiabatic energy losses and drift. Relative roles of these factors change in the course of an 11-year solar cycle. That can result in the changes in the energy dependence of the 11-year cosmic ray modulation. The minimum between the solar cycles 23 and 24 was extremely deep and long-lasting which led to the record high cosmic ray fluxes low-energy particles dominating. This was a signature of unusually soft energy spectrum of the cosmic rays. In this work we examine the energy dependence of the 11-year modulation during the last three solar cycles and argue that a soft energy spectrum was observed in the minimum of each cycle however only for particles below of energy around 10 GeV. From mid 1980s the energy dependence of cosmic rays became softer from minimum to minimum of solar activity. The work is based on the cosmic ray data of the spacecraft, balloon-borne and the ground-based observations.

Bazilevskaya, G A; Krainev, M B; Makhmutov, V S; Svirzhevskaya, A K; Svirzhevsky, N S

2014-01-01T23:59:59.000Z

176

High-energy cosmic ray muons in the Earth's atmosphere  

SciTech Connect (OSTI)

We present the calculations of the atmospheric muon fluxes at energies 10-10{sup 7} GeV based on a numerical-analytical method for solving the hadron-nucleus cascade equations. It allows the non-power-law behavior of the primary cosmic ray (PCR) spectrum, the violation of Feynman scaling, and the growth of the total inelastic cross sections for hadron-nucleus collisions with increasing energy to be taken into account. The calculations have been performed for a wide class of hadron-nucleus interaction models using directly the PCR measurements made in the ATIC-2 and GAMMA experiments and the parameterizations of the primary spectrum based on a set of experiments. We study the dependence of atmospheric muon flux characteristics on the hadronic interaction model and the influence of uncertainties in the PCR spectrum and composition on the muon flux at sea level. Comparison of the calculated muon energy spectra at sea level with the data from a large number of experiments shows that the cross sections for hadron-nucleus interactions introduce the greatest uncertainty in the energy region that does not include the knee in the primary spectrum.

Kochanov, A. A., E-mail: kochanov@iszf.irk.ru [Russian Academy of Sciences, Siberian Branch, Institute of Solar-Terrestrial Physics (Russian Federation); Sinegovskaya, T. S. [Irkutsk State Railway University (Russian Federation)] [Irkutsk State Railway University (Russian Federation); Sinegovsky, S. I., E-mail: sinegovsky@api.isu.ru [Irkutsk State University (Russian Federation)

2013-03-15T23:59:59.000Z

177

Diffusion coefficient and radial gradient of galactic cosmic rays  

E-Print Network [OSTI]

We present the temporal changes of the diffusion coefficient K of galactic cosmic rays (GCRs) at the Earth orbit calculated based on the experimental data using two different methods. The first approach is based on the Parker convection-diffusion approximation of GCR modulation [1]: i.e. K~Vr=dI where dI is the variation of the GCR intensity measured by neutron monitors (NM),V is the solar wind velocity and r is the radial distance. The second approach is based on the interplanetary magnetic field (IMF) data. It was suggested that parallel mean free path can be expressed in terms of B as in [2]-[4]. Using data of the product of the parallel mean free path and radial gradient of GCR calculated based on the GCR anisotropy data (Ahluwalia et al., this conference ICRC 2013, poster ID: 487 [5]), we estimate the temporal changes of the radial gradient of GCR at the Earth orbit. We show that the radial gradient exhibits a strong solar cycle dependence (11-year variation) and a weak solar magnetic cycle dependence (2...

Modzelewska, Renata

2015-01-01T23:59:59.000Z

178

Antiproton Flux in Cosmic Ray Propagation Models with Anisotropic Diffusion  

E-Print Network [OSTI]

Recently a cosmic ray propagation model has been introduced, where anisotropic diffusion is used as a mechanism to allow for $\\mathcal{O}(100)$ km/s galactic winds. This model predicts a reduced antiproton background flux, suggesting an excess is being observed. We implement this model in GALPROP v50.1 and perform a $\\chi^2$ analysis for B/C, $^{10}$Be/$^{9}$Be, and the recent PAMELA $\\bar{p}/p$ datasets. By introducing a power-index parameter $\\alpha$ that dictates the dependence of the diffusion coefficient $D_{xx}$ on height $|z|$ away from the galactic plane, we confirm that isotropic diffusion models with $\\alpha=0$ cannot accommodate high velocity convective winds suggested by ROSAT, while models with $\\alpha=1$ ($D_{xx}\\propto |z|$) can give a very good fit. A fit to B/C and $^{10}$Be/$^{9}$Be data predicts a lower $\\bar{p}/p$ flux ratio than the PAMELA measurement at energies between approximately 2 GeV to 20 GeV. A combined fit including in addition the $\\bar{p}/p$ data is marginal, suggesting only a partial contribution to the measured antiproton flux.

Phillip Grajek; Kaoru Hagiwara

2010-12-02T23:59:59.000Z

179

UHECR ESCAPE MECHANISMS FOR PROTONS AND NEUTRONS FROM GAMMA-RAY BURSTS, AND THE COSMIC-RAY-NEUTRINO CONNECTION  

SciTech Connect (OSTI)

The paradigm that gamma-ray burst fireballs are the sources of the ultra-high energy cosmic rays (UHECRs) is being probed by neutrino observations. Very stringent bounds can be obtained from the cosmic-ray (proton)-neutrino connection, assuming that the UHECRs escape as neutrons. In this study, we identify three different regimes as a function of the fireball parameters: the standard ''one neutrino per cosmic ray'' case, the optically thick (to neutron escape) case, and the case where leakage of protons from the boundaries of the shells (direct escape) dominates. In the optically thick regime, the photomeson production is very efficient, and more neutrinos will be emitted per cosmic ray than in the standard case, whereas in the direct escape-dominated regime, more cosmic rays than neutrinos will be emitted. We demonstrate that, for efficient proton acceleration, which is required to describe the observed UHECR spectrum, the standard case only applies to a very narrow region of the fireball parameter space. We illustrate with several observed examples that conclusions on the cosmic-ray-neutrino connection will depend on the actual burst parameters. We also show that the definition of the pion production efficiency currently used by the IceCube collaboration underestimates the neutrino production in the optically thick case. Finally, we point out that the direct escape component leads to a spectral break in the cosmic-ray spectrum emitted from a single source. The resulting ''two-component model'' can be used to even more strongly pronounce the spectral features of the observed UHECR spectrum than the dip model.

Baerwald, Philipp; Bustamante, Mauricio; Winter, Walter, E-mail: philipp.baerwald@physik.uni-wuerzburg.de, E-mail: mauricio.bustamante@physik.uni-wuerzburg.de, E-mail: winter@physik.uni-wuerzburg.de [Institut fuer Theoretische Physik und Astrophysik, Universitaet Wuerzburg, D-97074 Wuerzburg (Germany)

2013-05-10T23:59:59.000Z

180

Low energy secondary cosmic ray flux (gamma rays) monitoring and its constrains  

E-Print Network [OSTI]

Temporal variation of secondary cosmic rays (SCR) flux was measured during the several full and new moon and days close to them at Department of Physics, University of Mumbai, Mumbai (Geomagnetic latitude: 10.6 N), India. The measurements were done by using NaI (Tl) scintillation detector with energy threshold of 200 keV. The SCR flux shows sudden enhancement for approximately about 2 hour in counts during couple of events out of all experimental observations. The maximum Enhancement SCR flux is about 200% as compared to the diurnal trend of SCR temporal variations. Weather parameters (temperature and relative humidity) were continuously monitored during all observation. The influences of geomagnetic field, interplanetary parameters and tidal effect on SCR flux have been considered. Summed spectra corresponding to enhancement duration indicates appearance of atmospheric radioactivity which shows single gamma ray line. Detail investigation revealed the presence of radioactive Ar 41 . This measurements puts lim...

Raghav, Anil; Yadav, Virendra; Bijewar, Nitinkumar

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "int cosmic ray" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

TeV Burst of Gamma-Ray Bursts and Ultra High Energy Cosmic Rays  

E-Print Network [OSTI]

Some recent experiments detecting very high energy (VHE) gamma-rays above 10-20 TeV independently reported VHE bursts for some of bright gamma-ray bursts (GRBs). If these signals are truly from GRBs, these GRBs must emit a much larger amount of energy as VHE gamma-rays than in the ordinary photon energy range of GRBs (keV-MeV). We show that such extreme phenomena can be reasonably explained by synchrotron radiation of protons accelerated to \\sim 10^{20-21} eV, which has been predicted by Totani (1998a). Protons seem to carry about (m_p/m_e) times larger energy than electrons, and hence the total energy liberated by one GRB becomes as large as \\sim 10^{56} (\\Delta \\Omega / 4 \\pi) ergs. Therefore a strong beaming of GRB emission is highly likely. Extension of the VHE spectrum beyond 20 TeV gives a nearly model-independent lower limit of the Lorentz factor of GRBs, as $\\gamma \\gtilde 500$. Furthermore, our model gives the correct energy range and time variability of ordinary keV-MeV gamma-rays of GRBs by synchrotron radiation of electrons. Therefore the VHE bursts of GRBs strongly support the hypothesis that ultra high energy cosmic rays observed on the Earth are produced by GRBs.

Tomonori Totani

1998-10-14T23:59:59.000Z

182

KolmogorovSmirnov test as a tool to study the distribution of ultra-high energy cosmic ray sources  

Science Journals Connector (OSTI)

......distribution of ultra-high energy cosmic ray sources D. Harari...Bustillo 9500, Bariloche, 8400 Argentina We analyse in detail the two-dimensional...sources of the ultra-high energy cosmic rays. We confront...rays (CRs) is the enormous energies they can reach, which can......

D. Harari; S. Mollerach; E. Roulet

2009-04-01T23:59:59.000Z

183

Production of 26A1 and other extinct radionuclides by low-energy heavy cosmic rays in molecular clouds  

Science Journals Connector (OSTI)

... when heavy cosmic rays interact with ambient H and He in the molecular clouds. The Solar-System cosmic-ray flux is too low (by a factor of 30) (ref. ... energies as low as 10 MeV per nucleon is not known from observations in the Solar System6. The Compton telescope team4 therefore suggests heavy cosmic rays are 30 times more ...

Donald D. Clayton

1994-03-17T23:59:59.000Z

184

On the Energy Spectra of GeV/TeV Cosmic Ray Leptons  

SciTech Connect (OSTI)

Recent observations of cosmic ray electrons from several instruments have revealed various degrees of deviation in the measured electron energy distribution from a simple power-law, in a form of an excess around 0.1 to 1 TeV energies. An even more prominent deviation and excess has been observed in the fraction of cosmic ray positrons around 10 and 100 GeV energies. These observations have received considerable attention and many theoretical models have been proposed to explain them. The models rely on either dark matter annihilation/decay or specific nearby astrophysical sources, and involve several additional assumptions regarding the dark matter distribution or particle acceleration. In this paper we show that the observed excesses in the electron spectrum may be easily reproduced without invoking any unusual sources other than the general diffuse Galactic components of cosmic rays. The model presented here assumes a power-law injection of electrons (and protons) by supernova remnants, and evaluates their expected energy spectrum based on a simple kinetic equation describing the propagation of charged particles in the interstellar medium. The primary physical effect involved is the Klein-Nishina suppression of the electron cooling rate around TeV energies. With a very reasonable choice of the model parameters characterizing the local interstellar medium, we can reproduce the most recent observations by Fermi and HESS experiments. Interestingly, in our model the injection spectral index of cosmic ray electrons becomes comparable to, or even equal to that of cosmic ray protons. The Klein-Nishina effect may also affect the propagation of the secondary e{sup {+-}} pairs, and therefore modify the cosmic ray positron-to-electron ratio. We have explored this possibility by considering two mechanisms for production of e{sup {+-}} pairs within the Galaxy. The first is due to the decay of {pi}{sup {+-}}'s produced by interaction of cosmic ray nuclei with ambient protons. The second source discussed here is due to the annihilation of the diffuse Galactic {gamma}-rays on the stellar photon field. We find that high positron fraction increasing with energy, as claimed by the PAMELA experiment, cannot be explained in our model with the conservative set of the model parameters. We are able, however, to reproduce the PAMELA (as well as Fermi and HESS) results assuming high values of the starlight and interstellar gas densities, which would be more appropriate for vicinities of supernova remnants. A possible solution to this problem may be that cosmic rays undergo most of their interactions near their sources due to the efficient trapping in the far upstream of supernova shocks by self-generated, cosmic ray-driven turbulence.

Stawarz, Lukasz; /KIPAC, Menlo Park /Jagiellonian U., Astron. Observ.; Petrosian, Vahe; /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., Appl. Phys. Dept.; Blandford, Roger D.; /KIPAC, Menlo Park

2011-08-19T23:59:59.000Z

185

Cosmic rays, lithium abundance and excess entropy in galaxy clusters  

Science Journals Connector (OSTI)

......elements such as beryllium and boron are not produced during...Anisotropy Probe (WMAP) determination of the cosmic baryon density...mass from the predominant isotope of 7Li, making lines from these two isotopes blend easily. Until recently......

Biman B. Nath; Piero Madau; Joseph Silk

2006-02-01T23:59:59.000Z

186

A connection between star formation activity and cosmic rays in the starburst galaxy M82  

E-Print Network [OSTI]

from Earth, in the direction of the Ursa Major constellation5 . For hundreds of millions of years, M82 synchrotron emission observed in the central region of M82 suggests a very high cosmic-ray energy density-Ray Experiment Telescope experiment13 , nor during pre- vious very-high-energy (VHE, energy .100GeV) c

187

Detection of cosmic -rays using a heliostat field: the case of F. Arqueros1  

E-Print Network [OSTI]

ICRC 2001 Detection of cosmic -rays using a heliostat field: the case of GRAAL F. Arqueros1 , J detection system and the limited sampling of a realistic heliostat array impose severe limitations. 1 plant (heliostat field) as a ¡ -ray telescope with lower energy threshold than conven- tional ground

188

On the Observational Status of Ultrahigh Energy Cosmic Rays and their Possible Origin in Starburst-Like Galaxies  

E-Print Network [OSTI]

This paper presents a brief review of the current status of ultrahigh energy cosmic ray observations and discusses nearby starburst-like galaxies as their possible origin.

Diego F. Torres; Luis A. Anchordoqui

2005-05-13T23:59:59.000Z

189

The IceCube Collaboration: contributions to the 29th International Cosmic Ray Conference (ICRC 2005), Pune, India, Aug. 2005  

E-Print Network [OSTI]

In this document we collect the 18 contributions of the IceCube Collaboration to the 29th International Cosmic Ray Conference (ICRC 2005), Pune, India, Aug. 2005

The IceCube Collaboration

2005-09-13T23:59:59.000Z

190

Probing cosmic opacity at high redshifts with gamma-ray bursts  

Science Journals Connector (OSTI)

Probing the evolution of the universe at high redshifts with standard candles is a powerful way to discriminate dark energy models, where an open question nowadays is whether this component is constant or evolves with time. One possible source of ambiguity in this kind of analysis comes from cosmic opacity, which can mimic a dark energy behavior. However, most tests of cosmic opacity have been restricted to the redshift range zgamma-ray bursts, given the validity of the Amati relation, and the latest H(z) data we determine constraints on the cosmic opacity at high redshifts (z>2) for a flat ?CDM model. A possible degeneracy of the results with the adopted cosmological model is also investigated by considering a flat XCDM model. The limits on cosmic opacity in the redshift range 0gamma ray bursts samples are compatible with a transparent universe at 1? level and the results are independent of the dark energy equation of state parameter w.

R.?F.?L. Holanda and V.?C. Busti

2014-05-16T23:59:59.000Z

191

Lateral distribution of muons in IceCube cosmic ray events  

Science Journals Connector (OSTI)

In cosmic ray air showers, the muon lateral separation from the center of the shower is a measure of the transverse momentum that the muon parent acquired in the cosmic ray interaction. IceCube has observed cosmic ray interactions that produce muons laterally separated by up to 400m from the shower core, a factor of 6 larger distance than previous measurements. These muons originate in high pT (>2??GeV/c) interactions from the incident cosmic ray, or high-energy secondary interactions. The separation distribution shows a transition to a power law at large values, indicating the presence of a hard pT component that can be described by perturbative quantum chromodynamics. However, the rates and the zenith angle distributions of these events are not well reproduced with the cosmic ray models tested here, even those that include charm interactions. This discrepancy may be explained by a larger fraction of kaons and charmed particles than is currently incorporated in the simulations.

R. Abbasi et al. (IceCube Collaboration)

2013-01-07T23:59:59.000Z

192

Point-like gamma ray sources as signatures of distant accelerators of ultra high energy cosmic rays  

E-Print Network [OSTI]

We discuss the possibility of observing distant accelerators of ultra high energy cosmic rays in synchrotron gamma rays. Protons propagating away from their acceleration sites produce extremely energetic electrons during photo-pion interactions with cosmic microwave background photons. If the accelerator is embedded in a magnetized region, these electrons will emit high energy synchrotron radiation. The resulting synchrotron source is expected to be point-like and detectable in the GeV-TeV energy range if the magnetic field is at the nanoGauss level.

S. Gabici; F. A. Aharonian

2005-05-22T23:59:59.000Z

193

A Magnetized Local Supercluster and the Origin of the Highest Energy Cosmic Rays  

E-Print Network [OSTI]

A sufficiently magnetized Local Supercluster can explain the spectrum and angular distribution of ultra-high energy cosmic rays. We show that the spectrum of extragalactic cosmic rays with energies below $\\sim 10^{20}$ eV may be due to the diffusive propagation in the Local Supercluster with fields of $\\sim 10^{-8} - 10^{-7}$ Gauss. Above $\\sim 10^{20}$ eV, cosmic rays propagate in an almost rectilinear way which is evidenced by the change in shape of the spectrum at the highest energies. The fit to the spectrum requires that at least one source be located relatively nearby at $\\sim 10-15$ Mpc away from the Milky Way. We discuss the origin of magnetic fields in the Local Supercluster and the observable predictions of this model.

Pasquale Blasi; Angela V. Olinto

1998-06-19T23:59:59.000Z

194

Cosmic-ray-produced stable nuclides: various production rates and their implications  

SciTech Connect (OSTI)

The rates for a number of reactions producing certain stable nuclides, such as /sup 3/He and /sup 4/He, and fission in the moon are calculated for galactic-cosmic-ray particles and for solar protons. Solar-proton-induced reactions with bromine usually are not an important source of cosmogenic Kr isotopes. The /sup 130/Ba(n,p) reaction cannot account for the undercalculation of /sup 130/Xe production rates. Calculated production rates of /sup 15/N, /sup 13/C, and /sup 2/H agree fairly well with rates inferred from measured excesses of these isotopes in samples with long exposure ages. Cosmic-ray-induced fission of U and Th can produce significant amounts of fission tracks and of /sup 86/Kr, /sup 134/Xe, and /sup 136/Xe, especially in samples with long exposures to cosmic-ray particles.

Reedy, R.C.

1981-06-15T23:59:59.000Z

195

Prospects for identifying the sources of the Galactic cosmic rays with IceCube  

Science Journals Connector (OSTI)

We quantitatively address whether IceCube, a kilometer-scale neutrino detector under construction at the South Pole, can observe neutrinos pointing back at the accelerators of the Galactic cosmic rays. The photon flux from candidate sources identified by the Milagro detector in a survey of the TeV sky is consistent with the flux expected from a typical cosmic-ray generating supernova remnant interacting with the interstellar medium. We show here that IceCube can provide incontrovertible evidence of cosmic-ray acceleration in these sources by detecting neutrinos. We find that the signal is optimally identified by specializing to events with energies above 30?TeV where the atmospheric neutrino background is low. We conclude that evidence for a correlation between the Milagro and IceCube sky maps should be conclusive after several years.

Francis Halzen; Alexander Kappes; Aongus Murchadha

2008-09-04T23:59:59.000Z

196

High-Energy Cross Sections. II. Nucleon-Nucleon Cross Section at Cosmic-Ray Energies  

Science Journals Connector (OSTI)

Cosmic-ray measurements are capable of yielding reliable results for the cross section of a nucleus for proton or neutron collisions involving a not too small energy transfer. This cross section should therefore be less than, or at most equal to, the true nonelastic cross section (reaction cross section). Results of recent cosmic-ray work are assembled and compared with the reaction cross sections measured at 1.4 Bev with the Brookhaven Cosmotron; it is found that the cosmic-ray cross sections are significantly larger, even for Pb. Assuming a nonuniform distribution of the density of nuclear matter, one can explain this surprising effect as the result of an increase in the elementary nucleon-nucleon cross section with energy. It is shown that the elementary cross section (the average of ?pp and ?np) must be (120-20+30)10-27 cm2 in the neighborhood of 30 Bev.

Robert W. Williams

1955-06-01T23:59:59.000Z

197

Neutrino and cosmic-ray emission from multiple internal shocks in gamma-ray bursts  

E-Print Network [OSTI]

In the classical theory of gamma-ray bursts, it is expected that particles are accelerated at mildly relativistic shocks generated by the collisions of material ejected from a central engine. We consider neutrino and cosmic-ray emission from multiple emission regions since these internal collisions must occur at very different radii, from below the photosphere all the way out to the circumburst medium, as a consequence of the efficient dissipation of kinetic energy. We demonstrate that the different messengers originate from different collision radii, which means that multimessenger observations open windows for revealing the evolving GRB outflows. We find that, even in the internal shock model, the neutrino production can be dominated by emission from around the photosphere, i.e., the radius where the ejecta become transparent to gamma-ray emission. Possible subphotospheric contributions enhance the detectability. We predict a minimal neutrino flux per flavor at the level of E^2 J ~ 10^{-11} GeV cm^{-2} sr^{...

Bustamante, Mauricio; Murase, Kohta; Winter, Walter

2014-01-01T23:59:59.000Z

198

Cosmic ray abundance measurements with the CAKE balloon experiment  

E-Print Network [OSTI]

We present the results from the CAKE (Cosmic Abundance below Knee Energy) balloon experiment which uses nuclear track detectors. The final experiment goal is the determination of the charge spectrum of CR nuclei with Z > 30 in the primary cosmic radiation. The detector, which has a geometric acceptance of \\~ 1.7 m2 sr, was exposed in a trans-mediterranean stratospheric balloon flight. Calibrations of the detectors used (CR39 and Lexan), scanning strategies and algorithms for tracking particles in an automatic mode are presented. The present status of the results is discussed

S. Cecchini; T. Chiarusi; G. Giacomelli; S. Manzoor; E. Medinaceli; L. Patrizii; V. Togo

2005-10-25T23:59:59.000Z

199

Differential directional intensities of low energy cosmic ray muons near sea level  

E-Print Network [OSTI]

DIFFERENTIAL DIRECTIOiNAL INTEiNSITIES OF LOW ENERGY COSMIC RAY MUONS liR SEA LEVEL A Thesis by DAVID RUDOLPH DURDA Submitted to the Graduate College of Texas ASM University in partial fulfillment of the requirement for the degree of MASTER... OF SCIENCE May 1970 Physics DIFFERENTIAL DIRECTIONAL INTENSITIES OF LOW ENERGY COSMIC RAY MUONS NEAR SEA LEVEL A Thesis by DAVID RUDOLPH DURDA Approved as to style and content by: C airman o Committee Hea o Department Me er Mem er May 1970...

Durda, David Rudolph

2012-06-07T23:59:59.000Z

200

Light Nuclei and Isotope Abundances in Cosmic Rays. Results from AMS-01  

E-Print Network [OSTI]

Observations of the chemical and isotopic composition of light cosmic-ray nuclei can be used to constrain the astrophysical models of cosmic-ray transport and interactions in the Galaxy. Nearly 200,000 light nuclei (Z>2) have been observed by AMS-01 during the 10-day flight STS-91 in June 1998. Using these data, we have measured the relative abundance of light nuclei Li, Be, B and C in the kinetic energy range 0.35 - 45 GeV/nucleon.

N. Tomassetti

2011-06-11T23:59:59.000Z

Note: This page contains sample records for the topic "int cosmic ray" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Isotopic Composition of Light Nuclei in Cosmic Rays: Results from AMS-01  

Science Journals Connector (OSTI)

The variety of isotopes in cosmic rays allows us to study different aspects of the processes that cosmic rays undergo between the time they are produced and the time of their arrival in the heliosphere. In this paper, we present measurements of the isotopic ratios 2H/4He, 3He/4He, 6Li/7Li, 7Be/(9Be+10Be), and 10B/11B in the range 0.2-1.4GeV of kinetic energy per nucleon. The measurements are based on the data collected by the Alpha Magnetic Spectrometer, AMS-01, during the STS-91 flight in 1998 June.

M. Aguilar; J. Alcaraz; J. Allaby; B. Alpat; G. Ambrosi; H. Anderhub; L. Ao; A. Arefiev; L. Arruda; P. Azzarello; M. Basile; F. Barao; G. Barreira; A. Bartoloni; R. Battiston; R. Becker; U. Becker; L. Bellagamba; J. Berdugo; P. Berges; B. Bertucci; A. Biland; V. Bindi; G. Boella; M. Boschini; M. Bourquin; G. Bruni; M. Bunerd; J. D. Burger; W. J. Burger; X. D. Cai; P. Cannarsa; M. Capell; D. Casadei; J. Casaus; G. Castellini; I. Cernuda; Y. H. Chang; H. F. Chen; H. S. Chen; Z. G. Chen; N. A. Chernoplekov; T. H. Chiueh; Y. Y. Choi; F. Cindolo; V. Commichau; A. Contin; E. Cortina-Gil; D. Crespo; M. Cristinziani; T. S. Dai; C. dela Guia; C. Delgado; S. Di Falco; L. Djambazov; I. D'Antone; Z. R. Dong; M. Duranti; J. Engelberg; F. J. Eppling; T. Eronen; P. Extermann; J. Favier; E. Fiandrini; P. H. Fisher; G. Flgge; N. Fouque; Y. Galaktionov; M. Gervasi; F. Giovacchini; P. Giusti; D. Grandi; O. Grimm; W. Q. Gu; S. Haino; K. Hangarter; A. Hasan; V. Hermel; H. Hofer; W. Hungerford; M. Ionica; M. Jongmanns; K. Karlamaa; W. Karpinski; G. Kenney; D. H. Kim; G. N. Kim; K. S. Kim; T. Kirn; A. Klimentov; R. Kossakowski; A. Kounine; V. Koutsenko; M. Kraeber; G. Laborie; T. Laitinen; G. Lamanna; G. Laurenti; A. Lebedev; C. Lechanoine-Leluc; M. W. Lee; S. C. Lee; G. Levi; C. H. Lin; H. T. Liu; G. Lu; Y. S. Lu; K. Lbelsmeyer; D. Luckey; W. Lustermann; C. Maa; A. Margotti; F. Mayet; R. R. McNeil; M. Menichelli; A. Mihul; A. Mujunen; S. Natale; A. Oliva; F. Palmonari; M. Paniccia; H. B. Park; W. H. Park; M. Pauluzzi; F. Pauss; R. Pereira; E. Perrin; A. Pevsner; F. Pilo; M. Pimenta; V. Plyaskin; V. Pojidaev; M. Pohl; N. Produit; L. Quadrani; P. G. Rancoita; D. Rapin; D. Ren; Z. Ren; M. Ribordy; E. Riihonen; J. Ritakari; S. Ro; U. Roeser; R. Sagdeev; D. Santos; G. Sartorelli; P. Saouter; C. Sbarra; S. Schael; A. Schultz von Dratzig; G. Schwering; E. S. Seo; J. W. Shin; E. Shoumilov; V. Shoutko; T. Siedenburg; R. Siedling; D. Son; T. Song; F. R. Spada; F. Spinella; M. Steuer; G. S. Sun; H. Suter; X. W. Tang; Samuel C. C. Ting; S. M. Ting; N. Tomassetti; M. Tornikoski; J. Torsti; J. Trmper; J. Ulbricht; S. Urpo; E. Valtonen; J. Vandenhirtz; E. Velikhov; B. Verlaat; I. Vetlitsky; F. Vezzu; J. P. Vialle; G. Viertel; D. Vit; H. Von Gunten; S. Waldmeier Wicki; W. Wallraff; J. Z. Wang; K. Wiik; C. Williams; S. X. Wu; P. C. Xia; S. Xu; Z. Z. Xu; J. L. Yan; L. G. Yan; C. G. Yang; J. Yang; M. Yang; S. W. Ye; H. Y. Zhang; Z. P. Zhang; D. X. Zhao; F. Zhou; Y. Zhou; G. Y. Zhu; W. Z. Zhu; H. L. Zhuang; A. Zichichi; B. Zimmermann; P. Zuccon

2011-01-01T23:59:59.000Z

202

Muon Excess in Cosmic Rays and at CDF: Signs for a Hidden Sector?  

E-Print Network [OSTI]

In this letter we discuss a certain class of Hidden Valley models where the dynamics in the hidden sector are close to a strongly coupled conformal fixed point. We show that these models can explain the excess in cosmic ray muon events with high muon multiplicities that has been reported from cosmic ray studies with the ALEPH and DELPHI detectors. We further point out that these models can also at least partially account for the excess in multi-muon events that was found by the CDF experiment. Finally we discuss possible signatures of these models at the LHC.

Thomas Gehrmann; Nicolas Greiner; Pedro Schwaller

2008-12-22T23:59:59.000Z

203

Medipix/Timepix cosmic ray tracking on BEXUS stratospheric balloon flights  

Science Journals Connector (OSTI)

Results of the first two experiments using semiconductor pixel detectors of the Medipix family for cosmic ray imaging in the stratospheric environment are presented. The original detecting device was based on the hybrid pixel detectors Medipix2 and Timepix developed at CERN with USB interface developed at the Institute of Experimental and Applied Physics of Czech Technical University in Prague. The detectors were used in tracking mode allowing them to operate as an active nuclear emulsion. Extensive datasets of different types of cosmic ray tracks were acquired in the stratospheric radiation environment, sorted and analyzed. Detector performance was evaluated for further design implications of proposed usage on satellites.

J. Urbar; J. Scheirich; J. Jakubek

2011-01-01T23:59:59.000Z

204

arXiv:0706.3940v1[astro-ph]26Jun2007 30th International Cosmic Ray Conference  

E-Print Network [OSTI]

- high energy cosmic rays. The Southern Auger Observatory in Mendoza province, Argentina, is approaching, Houghton, MI 49931, USA 2 Observatorio Pierre Auger, Av. San Mart´in Norte 304, (5613) Malarg¨ue, Argentina and composition of ultra-high energy cosmic rays up to and beyond the predicted GZK feature. We are obtaining

205

Predicting neutron production from cosmic-ray muons Y.-F. Wang, V. Balic, and G. Gratta  

E-Print Network [OSTI]

Predicting neutron production from cosmic-ray muons Y.-F. Wang, V. Balic, and G. Gratta Physics, Milano, Italy Received 26 January 2001; published 5 June 2001 Fast neutrons from cosmic-ray muons hampered by the difficulty of measuring and calculating neutron production with sufficient accuracy. Indeed

Gratta, Giorgio

206

Relative recovery of galactic and anomalous cosmic rays at 1 AU: Further evidence for modulation in the heliosheath  

E-Print Network [OSTI]

as the inclination of the heliospheric neutral current sheet decreases from 32° to its minimum value of 8°. INDEX TERMS: 2104 Interplanetary Physics: Cosmic rays; 2124 Interplanetary Physics: Heliopause and solar wind: anomalous cosmic rays, heliosheath, coronal mass ejections, interplanetary shocks, solar wind, galactic

Reames, Donald V.

207

Modeling high-energy cosmic ray induced terrestrial muon flux: A lookup table  

Science Journals Connector (OSTI)

On geological timescales, the Earth is likely to be exposed to an increased flux of high-energy cosmic rays (HECRs) from astrophysical sources such as nearby supernovae, gamma-ray bursts or by galactic shocks. Typical cosmic ray energies may be much higher than the ? 1 GeV flux which normally dominates. These high-energy particles strike the Earth's atmosphere initiating an extensive air shower. As the air shower propagates deeper, it ionizes the atmosphere by producing charged secondary particles. Secondary particles such as muons and thermal neutrons produced as a result of nuclear interactions are able to reach the ground, enhancing the radiation dose. Muons contribute 85% to the radiation dose from cosmic rays. This enhanced dose could be potentially harmful to the biosphere. This mechanism has been discussed extensively in literature but has never been quantified. Here, we have developed a lookup table that can be used to quantify this effect by modeling terrestrial muon flux from any arbitrary cosmic ray spectra with 10GeV to 1PeV primaries. This will enable us to compute the radiation dose on terrestrial planetary surfaces from a number of astrophysical sources.

Dimitra Atri; Adrian L. Melott

2011-01-01T23:59:59.000Z

208

Ultra-high energy cosmic rays, cascade gamma-rays, and high-energy neutrinos from gamma-ray bursts  

E-Print Network [OSTI]

Gamma-ray bursts (GRBs) are sources of energetic, highly variable fluxes of gamma rays, which demonstrates that they are powerful particle accelerators. Besides relativistic electrons, GRBs should also accelerate high-energy hadrons, some of which could escape cooling to produce ultra-high energy cosmic rays (UHECRs). Acceleration of high-energy hadrons in GRB blast waves will be established if high-energy neutrinos produced through photopion interactions in the blast wave are detected from GRBs. Limitations on the energy in nonthermal hadrons and the number of expected neutrinos are imposed by the fluxes from pair-photon cascades initiated in the same processes that produce neutrinos. Only the most powerful bursts at fluence levels >~ 3e-4 erg/cm^2 offer a realistic prospect for detection of >> TeV neutrinos. Detection of high-energy neutrinos is likely if GRB blast waves have large baryon loads and Doppler factors <~ 200. Cascade gamma rays will accompany neutrino production and might already have been detected as anomalous emission components in the spectra of some GRBs. Prospects for detection of GRBs in the Milky Way are also considered.

Charles D. Dermer; Armen Atoyan

2006-06-26T23:59:59.000Z

209

Search for a dark matter particle in high energy cosmic rays  

E-Print Network [OSTI]

Existing data hints that high energy cosmic ray experiments may offer the most promissing shot at finding a dark matter particle. A search in the PeV mass range is suggested, where the discovery of such a particle might help explain the GZK cutoff violation data.

Yukio Tomozawa

2008-04-09T23:59:59.000Z

210

COSMIC-RAY MUON TOMOGRAPHY AND ITS APPLICATION TO THE DETECTION OF HIGH-Z MATERIALS  

E-Print Network [OSTI]

. The mean energy of the muons at the ground is about 4 GeV. The integral 1 #12;intensity of vertical muons change their directions due to the multiple scattering, lose their energy and finally get stopped. A muonCOSMIC-RAY MUON TOMOGRAPHY AND ITS APPLICATION TO THE DETECTION OF HIGH-Z MATERIALS Konstantin

Kurien, Susan

211

The energy spectrum of neutrons produced by cosmic ray muons in LVD  

Science Journals Connector (OSTI)

The energy spectrum of neutrons produced by cosmic ray muons in the underground detector LVD (3650 m.w.e.) is obtained for the energy range of 30450 MeV. The spectrum is derived using the energy release spectrum...

N. Yu. Agafonova; V. V. Boyarkin

2009-05-01T23:59:59.000Z

212

Detection of high energy cosmic rays with the resonant gravitational wave detector NAUTILUS and EXPLORER  

E-Print Network [OSTI]

The cryogenic resonant gravitational wave detectors NAUTILUS and EXPLORER, made of an aluminum alloy bar, can detect cosmic ray showers. At temperatures above 1 K, when the material is in the normal conducting state, the measured signals are in good agreement with the values expected based on the cosmic rays data and on the thermo-acoustic model. When NAUTILUS was operated at the temperature of 0.14 K, in superconductive state, large signals produced by cosmic ray interactions, more energetic than expected, were recorded. The NAUTILUS data in this case are in agreement with the measurements done by a dedicated experiment on a particle beam. The biggest recorded event was in EXPLORER and excited the first longitudinal mode to a vibrational energy of about 670 K, corresponding to about 360 TeV absorbed in the bar. Cosmic rays can be an important background in future acoustic detectors of improved sensitivity. At present, they represent a useful tool to verify the gravitational wave antenna performance.

P. Astone; D. Babusci; M. Bassan; P. Bonifazi; G. Cavallari; E. Coccia; S. D'Antonio; V. Fafone; G. Giordano; C. Ligi; A. Marini; G. Mazzitelli; Y. Minenkov; I. Modena; G. Modestino; A. Moleti; G. V. Pallottino; G. Pizzella; L. Quintieri; A. Rocchi; F. Ronga; R. Terenzi; M. Visco

2008-06-14T23:59:59.000Z

213

30TH INTERNATIONAL COSMIC RAY CONFERENCE Telescope Array Aperture: Mono, Stereo and Hybrid  

E-Print Network [OSTI]

-sky background photons are also considered in simulations by us- ing real observational data obtained at the site of Physics, University of Utah, Salt Lake City, UT 84112-0830, USA 4 Department of Physics and Astronomy purpose of TA is to de- termine the energy spectrum of ultra high energy cosmic rays, and a precise

214

NUMERICAL STUDIES OF COSMIC-RAY INJECTION AND ACCELERATION Hyesung Kang  

E-Print Network [OSTI]

; accepted 2002 July 9 ABSTRACT A numerical scheme that incorporates a thermal leakage injection model in the precursor region, especially in front of strong, highly modified shocks. The `` thermal leakage '' injectionNUMERICAL STUDIES OF COSMIC-RAY INJECTION AND ACCELERATION Hyesung Kang Department of Earth

Gieseler, Udo D. J.

215

CENTAURUS A: THE EXTRAGALACTIC SOURCE OF COSMIC RAYS WITH ENERGIES ABOVE THE KNEE  

SciTech Connect (OSTI)

The origin of cosmic rays at all energies is still uncertain. In this paper, we present and explore an astrophysical scenario to produce cosmic rays with energy ranging from below 10{sup 15} to 3 Multiplication-Sign 10{sup 20} eV. We show here that just our Galaxy and the radio galaxy Cen A, each with their own galactic cosmic-ray particles but with those from the radio galaxy pushed up in energy by a relativistic shock in the jet emanating from the active black hole, are sufficient to describe the most recent data in the PeV to near ZeV energy range. Data are available over this entire energy range from the KASCADE, KASCADE-Grande, and Pierre Auger Observatory experiments. The energy spectrum calculated here correctly reproduces the measured spectrum beyond the knee and, contrary to widely held expectations, no other extragalactic source population is required to explain the data even at energies far below the general cutoff expected at 6 Multiplication-Sign 10{sup 19} eV, the Greisen-Zatsepin-Kuz'min turnoff due to interaction with the cosmological microwave background. We present several predictions for the source population, the cosmic-ray composition, and the propagation to Earth which can be tested in the near future.

Biermann, Peter L. [Max-Planck-Institute for Radioastronomy, Auf dem Huegel 69, D-53121 Bonn (Germany); De Souza, Vitor, E-mail: plbiermann@mpifr-bonn.mpg.de, E-mail: vitor@ifsc.usp.br [Instituto de Fisica de Sao Carlos, Universidade de Sao Paulo (Brazil)

2012-02-10T23:59:59.000Z

216

SPECTRA OF COSMIC-RAY PROTONS AND HELIUM PRODUCED IN SUPERNOVA REMNANTS  

SciTech Connect (OSTI)

Data obtained in the Advanced Thin Ionization Calorimeter (ATIC-2), Cosmic Ray Energetics and Mass (CREAM), and Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics (PAMELA) experiments suggest that the elemental interstellar spectra of cosmic rays below the knee at a few times 10{sup 6} GeV are not simple power laws, but that they experience hardening at a magnetic rigidity of about 240 GV. Another essential feature is the difference between proton and helium energy spectra, such that the He/p ratio increases by more than 50% in the energy range from 10{sup 2} to 10{sup 4} GV. We consider the concavity of the particle spectrum resulting from the nonlinear nature of diffusive shock acceleration in supernova remnants (SNRs) as a possible reason for the observed spectrum hardening. The increase of the helium-to-proton ratio with energy can be interpreted as a consequence of cosmic-ray acceleration by forward and reverse shocks in SNRs. The contribution of particles accelerated by reverse shocks makes the concavity of the produced overall cosmic-ray spectrum more pronounced. The spectra of protons and helium nuclei accelerated in SNRs and released into the interstellar medium are calculated. The derived steady-state interstellar spectra are in reasonably good agreement with observations.

Ptuskin, Vladimir; Zirakashvili, Vladimir [Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation of the Russian Academy of Science (IZMIRAN), Troitsk, Moscow Region 142190 (Russian Federation)] [Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation of the Russian Academy of Science (IZMIRAN), Troitsk, Moscow Region 142190 (Russian Federation); Seo, Eun-Suk [Department of Physics and Institute of Physical Science and Technology, University of Maryland, College Park, MD 20742 (United States)] [Department of Physics and Institute of Physical Science and Technology, University of Maryland, College Park, MD 20742 (United States)

2013-01-20T23:59:59.000Z

217

ENERGY SPECTRUM OF PRIMARY COSMIC RAYS ABOVE 1017 OBTAINED USING AKENO 20 KM2  

E-Print Network [OSTI]

OG 6.3-3 ENERGY SPECTRUM OF PRIMARY COSMIC RAYS ABOVE 1017 EV OBTAINED USING AKENO 20 KM2 ARRAY M, Tokyo Institute of Technology, Tokyo 152, Japan . Institute of High Energy Physics, Academia Sinica these showers, 60 of them are initiated by primaries with energies larger than 1019 eV. The energy spectrum

218

Ecosystem-scale measurements of biomass water using cosmic ray neutrons  

E-Print Network [OSTI]

Ecosystem-scale measurements of biomass water using cosmic ray neutrons Trenton E. Franz,1,2 Marek 2013. [1] Accurate estimates of biomass are imperative for under- standing the global carbon cycle. However, measurements of biomass and water in the biomass are difficult to obtain at a scale consistent

Zreda, Marek

219

Cosmic Rays from the Knee to the Ankle - Status and Prospects -  

E-Print Network [OSTI]

Recent progress in cosmic ray physics covering the energy range from about 10^{14} eV to 10^{19} eV is reviewed. The most prominent features of the energy spectrum are the so called `knee' at E ~ 3 * 10^{15} eV and the `ankle' at few 10^{18} eV. Generally, the origin of the knee is understood as marking the limiting energy of galactic accelerators and/or the onset of increasing outflow of particles from the galaxy while the ankle is considered to mark the transition from galactic to extragalactic cosmic rays. Alternative theories do exist and shall be sketched. A key observable to answer the still open questions about the cosmic ray origin and to discriminate between various models is given by measuring the chemical composition or - more directly - by measuring energy spectra of individual cosmic ray mass groups. The status of present analyses is critically discussed and new experimental endeavors carried out in order to improve both the statistics and the quality of data particularly at energies above the kn...

Kampert, K H

2006-01-01T23:59:59.000Z

220

Observation of the Ankle and Evidence for a High-Energy Break in the Cosmic Ray  

E-Print Network [OSTI]

Observation of the Ankle and Evidence for a High-Energy Break in the Cosmic Ray Spectrum R known as "the ankle" near 3 ? 1018 eV, and strong evidence for a supression near 6 ? 1019 eV. 1

Note: This page contains sample records for the topic "int cosmic ray" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Cosmic Ray Acceleration beyond the Knee up to the Ankle in the Galactic Wind Halo  

E-Print Network [OSTI]

Cosmic Ray Acceleration beyond the Knee up to the Ankle in the Galactic Wind Halo Vladimir the so-called knee at several #2;10 15 eV to the so-called ankle at a few #2;10 18 eV total energy

222

Cosmic Rays from the Knee to the Ankle - Status and Prospects -  

E-Print Network [OSTI]

Recent progress in cosmic ray physics covering the energy range from about 10^{14} eV to 10^{19} eV is reviewed. The most prominent features of the energy spectrum are the so called `knee' at E ~ 3 * 10^{15} eV and the `ankle' at few 10^{18} eV. Generally, the origin of the knee is understood as marking the limiting energy of galactic accelerators and/or the onset of increasing outflow of particles from the galaxy while the ankle is considered to mark the transition from galactic to extragalactic cosmic rays. Alternative theories do exist and shall be sketched. A key observable to answer the still open questions about the cosmic ray origin and to discriminate between various models is given by measuring the chemical composition or - more directly - by measuring energy spectra of individual cosmic ray mass groups. The status of present analyses is critically discussed and new experimental endeavors carried out in order to improve both the statistics and the quality of data particularly at energies above the knee will be summarized.

Karl-Heinz Kampert

2006-11-29T23:59:59.000Z

223

Cosmic Ray Acceleration beyond the Knee up to the Ankle in the Galactic Wind Halo  

E-Print Network [OSTI]

Cosmic Ray Acceleration beyond the Knee up to the Ankle in the Galactic Wind Halo Vladimir Acceleration beyond the Knee up to the Ankle in the Galactic Wind Halo2 radius 100 kpc in this model. This size mechanism to produce the observed CRs beyond the so-called knee at several ?1015 eV to the so-called ankle

224

29th International Cosmic Ray Conference Pune (2005) 00, 101-104 The Pierre Auger Observatory  

E-Print Network [OSTI]

Auger, Av. San Martin Norte 304, 5613 Malarge, Argentina (b) Pierre Auger Collaboration: http was designed for a high statistics, full sky study of cosmic rays at the highest energies. Energy, direction, now under construction in the Province of Mendoza, Argentina, is well over half finished. Active

225

28th International Cosmic Ray Conference 369 Asymmetries Observed In Giant Air Showers Using Water  

E-Print Network [OSTI]

, Universidad Nacional de La Plata, C.C. 67 - 1900 La Plata, Argentina (2) PAO, Av. San Martin Norte 304, (5613) Malargue, Argentina Abstract Evidence of azimuthal asymmetries in the time structure and signal size has of the foremost issues in astrophysics today is the origin of the ultra high energy cosmic rays (UHECR

226

Solar modulation parameter for cosmic rays since 1936 reconstructed from groundbased neutron  

E-Print Network [OSTI]

Solar modulation parameter for cosmic rays since 1936 reconstructed from groundbased neutron the world network of sea level neutron monitors and covers the period since April 1964. The part between February 1951 and March 1964 is based on data from one to two mountain neutron monitors of IGY type

Usoskin, Ilya G.

227

General Solution of a Fractional Diffusion-Advection Equation for Solar Cosmic-Ray Transport  

E-Print Network [OSTI]

In this effort we exactly solve the fractional diffusion-advection equation for solar cosmic-ray transport proposed in \\cite{LE2014} and give its {\\it general solution} in terms of hypergeometric distributions. Also, we regain all the results and approximations given in \\cite{LE2014} as {\\it particular cases} of our general solution.

M. C. Rocca; A. R. Plastino; A. Plastino; A. L. De Paoli

2014-11-30T23:59:59.000Z

228

General Solution of a Fractional Diffusion-Advection Equation for Solar Cosmic-Ray Transport  

E-Print Network [OSTI]

In this effort we exactly solve the fractional diffusion-advection equation for solar cosmic-ray transport proposed in \\cite{LE2014} and give its {\\it general solution} in terms of hypergeometric distributions. Also, we regain all the results and approximations given in \\cite{LE2014} as {\\it particular cases} of our general solution.

Rocca, M C; Plastino, A; De Paoli, A L

2014-01-01T23:59:59.000Z

229

A Lookup Table to Compute High Energy Cosmic Ray Effects on Terrestrial Atmospheric Chemistry  

E-Print Network [OSTI]

chemistry changes. We have created a table that, with the use of the NGSFC code can be used to simulate the effects of high energy cosmic rays (10 GeV to 1 PeV) ionizing the atmosphere. By interpolation, the table can be used to generate values for other...

Atri, Dimitra

2009-04-27T23:59:59.000Z

230

On the Stellar Origin of Low Energy Cosmic Rays [and Discussion  

Science Journals Connector (OSTI)

...different; the rate of energy release during the flare...same order as the normal energy release of the star in...the Sun. Adopting the factor, which has been determined...of the Sun, for the conversion of flare energy to cosmic-ray energy...

1975-01-01T23:59:59.000Z

231

ULTRA HIGH ENERGY COSMIC RAY SPECTRUM Baltrusaitis, R.M., Cady7  

E-Print Network [OSTI]

., Steck, D. Department of Physics, University of Utah, Salt Lake City, UT 84112 ABSTRACT Ultra-high energy and is essentially model independent. Shown in Fig. 1 is the raw energy distribution of observed events. #12;2.94 ± 0OG 5.1-2 146 ULTRA HIGH ENERGY COSMIC RAY SPECTRUM Baltrusaitis, R.M., Cady7 , R., Cassiday, G

232

Intensity of Upward Muon Flux Due to Cosmic-Ray Neutrinos Produced in the Atmosphere  

DOE R&D Accomplishments [OSTI]

Calculations were performed to determine the upward going muon flux leaving the earth's surface after production by cosmic-ray neutrinos in the crust. Only neutrinos produced in the earth's atmosphere are considered. Rates of the order of one per 100 sq m/day might be expected if an intermediate boson exists and has a mass less than 2 Bev. (auth)

Lee, T. D.; Robinson, H.; Schwartz, M.; Cool, R.

1963-06-00T23:59:59.000Z

233

Environmental limits on the non-resonant cosmic-ray current-driven instability  

E-Print Network [OSTI]

We investigate the so-called non-resonant cosmic-ray streaming instability, first discussed by Bell (2004). The extent to which thermal damping and ion-neutral collisions reduce the growth of this instability is calculated. Limits on the growth of the non-resonant mode in SN1006 and RX J1713.7-3946 are presented.

B. Reville; J. G. Kirk; P. Duffy; S. O'Sullivan

2008-02-22T23:59:59.000Z

234

High Energy Cosmic Rays from Local GRBs Armen Atoyan 1 and Charles D. Dermer 2  

E-Print Network [OSTI]

. The origin of the ankle in the CR spectrum at Eank # 4 ? 10 18 eV is due to photopair energy losses of UHECRsHigh Energy Cosmic Rays from Local GRBs Armen Atoyan 1 and Charles D. Dermer 2 1 CRM, Universit rays with energies E between # 0.1 - 1 PeV and the energy of the second knee at E2 # 3 ? 10 17 e

235

A Gamma-Ray Burst/Pulsar for Cosmic-Ray Positrons with a Dark Matter-like Spectrum  

E-Print Network [OSTI]

We propose that a nearby gamma-ray burst (GRB) or GRB-like (old, single and short-lived) pulsar/supernova remnant/microquasar about 10^{5-6} years ago may be responsible for the excesses of cosmic-ray positrons and electrons recently observed by the PAMELA, ATIC/PPB-BETS, Fermi and HESS experiments. We can reproduce the smooth Fermi/HESS spectra as well as the spiky ATIC/PPB-BETS spectra. The spectra have a sharp cutoff that is similar to the dark matter predictions, sometimes together with a line (not similar), since higher energy cosmic-rays cool faster where the cutoff/line energy marks the source age. A GRB-like astrophysical source is expected to have a small but finite spread in the cutoff/line as well as anisotropy in the cosmic-ray and diffuse gamma-ray flux, providing a method for the Fermi and future CALET experiments to discriminate between dark matter and astrophysical origins.

Kunihito Ioka

2010-06-15T23:59:59.000Z

236

Observation of the Cosmic Ray Moon shadowing effect with ARGO-YBJ  

E-Print Network [OSTI]

Cosmic rays are hampered by the Moon and a deficit in its direction is expected (the so-called \\emph{Moon shadow}). The Moon shadow is an important tool to determine the performance of an air shower array. Indeed, the westward displacement of the shadow center, due to the bending effect of the geomagnetic field on the propagation of cosmic rays, allows the setting of the absolute rigidity scale of the primary particles inducing the showers recorded by the detector. In addition, the shape of the shadow permits to determine the detector point spread function, while the position of the deficit at high energies allows the evaluation of its absolute pointing accuracy. In this paper we present the observation of the cosmic ray Moon shadowing effect carried out by the ARGO-YBJ experiment in the multi-TeV energy region with high statistical significance (55 standard deviations). By means of an accurate Monte Carlo simulation of the cosmic rays propagation in the Earth-Moon system, we have studied separately the effect of the geomagnetic field and of the detector point spread function on the observed shadow. The angular resolution as a function of the particle multiplicity and the pointing accuracy have been obtained. The primary energy of detected showers has been estimated by measuring the westward displacement as a function of the particle multiplicity, thus calibrating the relation between shower size and cosmic ray energy. The stability of the detector on a monthly basis has been checked by monitoring the position and the deficit of the Moon shadow. Finally, we have studied with high statistical accuracy the shadowing effect in the "day"/"night" time looking for possible effect induced by the solar wind.

The ARGO-YBJ Collaboration

2011-07-25T23:59:59.000Z

237

Propagation and energy deposition of cosmic rays' muons on terrestrial environments  

E-Print Network [OSTI]

Earth is constantly struck by radiation coming from the interstellar medium. The very low energy end of the spectrum is shielded by the geomagnetic field but charged particles with energies higher than the geomagnetic cutoff will penetrate the atmosphere and are likely to interact, giving rise to secondary particles. Some astrophysical events, such as gamma ray bursts and supernovae, when happening at short distances, may affect the planet's biosphere due to the temporary enhanced radiation flux. Muons are abundantly produced by high energy cosmic rays in the Earth's atmosphere. These particles, due to their low cross section, are able to penetrate deep underground and underwater, with the possibility of affecting biological niches normally considered shielded from radiation. We investigate the interaction of muons produced by high energy cosmic rays on Earth's atmosphere using the Geant4 toolkit. We analyze penetration power in water and crust and also the interaction effects within bacteria-like material ac...

Marinho, Franciole; Galante, Douglas

2014-01-01T23:59:59.000Z

238

Cosmic ray acceleration in supernova remnants and the FERMI/PAMELA data  

Science Journals Connector (OSTI)

We discuss recent observations of high energy cosmic ray positrons and electrons in the context of hadronic interactions in supernova remnants (SNRs), the suspected accelerators of galactic cosmic rays. Diffusive shock acceleration can harden the energy spectrum of secondary positrons relative to that of the primary protons and electrons and thus explain the rise in the positron fraction observed by PAMELA above 10GeV. We normalize the hadronic interaction rate by holding pion decay to be responsible for the gamma rays detected by HESS from some SNRs. By simulating the spatial and temporal distribution of SNRs in the Galaxy according to their known statistics, we are able to then fit the electron (plus positron) energy spectrum measured by Fermi. It appears that IceCube has good prospects for detecting the hadronic neutrino fluxes expected from nearby SNRs.

Markus Ahlers; Philipp Mertsch; Subir Sarkar

2009-12-29T23:59:59.000Z

239

High Redshift Gamma-Ray Bursts: Observational Signatures of Superconducting Cosmic Strings?  

E-Print Network [OSTI]

The high-redshift gamma-ray bursts (GRBs), GRBs 080913 and 090423, challenge the conventional GRB progenitor models by their short durations, typical for short GRBs, and their high energy releases, typical for long GRBs. Meanwhile, the GRB rate inferred from high-redshift GRBs also remarkably exceeds the prediction of the collapsar model, with an ordinary star formation history. We show that all these contradictions could be eliminated naturally, if we ascribe some high-redshift GRBs to electromagnetic bursts of superconducting cosmic strings. High-redshift GRBs could become a reasonable way to test the superconducting cosmic string model, because the event rate of cosmic string bursts increases rapidly with increasing redshifts, whereas the collapsar rate decreases.

K. S. Cheng; Yun-Wei Yu; T. Harko

2010-06-11T23:59:59.000Z

240

arXiv:astro-ph/9812260v114Dec1998 Galactic cosmic rays and gamma rays: a unified approach  

E-Print Network [OSTI]

. Strong1 and Igor V. Moskalenko1,2 1Max-Planck-Institut f¨ur extraterrestrische Physik, Postfach 1603, D sections based on the observed cosmic-ray abundances (see Webber, Lee, & Gupta 1992). The B/C data is used cross sections. A re-evaluation of the halo size is desirable since new 10Be/ 9Be data are available

Moskalenko, Igor V.

Note: This page contains sample records for the topic "int cosmic ray" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Cosmic Gamma-Ray Bursts as a Probe of Star Formation History  

E-Print Network [OSTI]

The cosmic gamma-ray burst (GRB) formation rate, as derived from the variability-luminosity relation for long-duration GRBs, is compared with the cosmic star formation rate. If GRBs are related to the collapse of massive stars, one expects the GRB rate to be approximately proportional to the star formation rate. We found that these two rates have similar slopes at low redshift. This suggests that GRBs do indeed track the star formation rate of the Universe, which in turn implies that the formation rate of massive stars that produce GRBs is proportional to the total star formation rate. It also implies that we might be able to use GRBs as a probe of the cosmic star formation rate at high redshift. We find that the cosmic star formation rate inferred from the variability-luminosity relation increases steeply with redshift at z > 3. This is in apparent contrast to what is derived from measurements of the cosmic star formation rate at high redshift from optical observations of field galaxies, suggesting that much high-z star formation is being missed in the optical surveys, even after corrections for dust extinction have been made.

Enrico Ramirez-Ruiz; Edward E. Fenimore; Neil Trentham

2000-10-29T23:59:59.000Z

242

Search for AntiparticleSearch for Antiparticle in Cosmic Raysin Cosmic Rays  

E-Print Network [OSTI]

-Polar I 2006: PAMELA 2007: Solar minimum BESS-Polar II 2010+: AMS-02 4 #12;5 Search for Primordial--ray Dataray Data PrecisePrecise spectraspectra Propagation, solar modulation, chargePropagation, solar> Z JET/IDC Rigidity TOF , dE/dx #12;8 BESS Ballooning 1993~ 2000, BESS, North Canada 2002, BESS

Yamamoto, Hirosuke

243

Tests of a calorimetric technique for measuring the energy of cosmic ray muons in the TeV energy range  

Science Journals Connector (OSTI)

Previous energy measurements of cosmic ray muons have used magnetic spectrometers to measure the momentum of muons. Measurements using magnets fail for muons in the TeV range because at ultra-high muon energies, ...

A. P. Chikkatur; L. Bugel; A. Alton

1997-06-01T23:59:59.000Z

244

The distribution of cosmic-ray ionization rates in diffuse molecular clouds as probed by H3+  

Science Journals Connector (OSTI)

...Chemistry, astronomy and physics of H3+ organized and...cosmic-ray ionization rates in diffuse molecular...jhu.edu Department of Physics and Astronomy, Johns...assume that the ionization rate does not pass below some value set...

2012-01-01T23:59:59.000Z

245

A Search for Possible Mesolensing of Cosmic Gamma-Ray Bursts: II. Double and Triple Bursts in the BATSE Catalog  

Science Journals Connector (OSTI)

The paper is devoted to searching for a possible phenomenon of the gravitational lensing of cosmic gamma-ray bursts on celestial bodies of a globular cluster ... (mesolensing). If this phenomenon takes place, gamma

O. S. Ougolnikov

2003-03-01T23:59:59.000Z

246

Ultra-high energy cosmic ray investigations by means of EAS muon density measurements  

E-Print Network [OSTI]

A new approach to investigations of ultra-high energy cosmic rays based on the ground-level measurements of the spectra of local density of EAS muons at various zenith angles is considered. Basic features of the local muon density phenomenology are illustrated using a simple semi-analytical model. It is shown that muon density spectra are sensitive to the spectrum slope, primary composition, and to the features of hadronic interaction. New experimental data on muon bundles at zenith angles from 30 degrees to horizon obtained with the coordinate detector DECOR are compared with CORSIKA-based simulations. It is found that measurements of muon density spectra in inclined EAS give possibility to study characteristics of primary cosmic ray flux in a very wide energy range from 10^15 to 10^19 eV.

N. S. Barbashina; A. G. Bogdanov; D. V. Chernov; A. N. Dmitrieva; D. M. Gromushkin; V. V. Kindin; R. P. Kokoulin; K. G. Kompaniets; G. Mannocchi; A. A. Petrukhin; O. Saavedra; V. V. Shutenko; D. A. Timashkov; G. Trinchero; I. I. Yashin

2007-01-11T23:59:59.000Z

247

Studying High $p_T$ Muons in Cosmic-Ray Air Showers  

E-Print Network [OSTI]

Most cosmic-ray air shower arrays have focused on detecting electromagnetic shower particles and low energy muons. A few groups (most notably MACRO + EASTOP and SPASE + AMANDA) have studied the high energy muon component of showers. However, these experiments had small solid angles, and did not study muons far from the core. The IceTop + IceCube combination, with its 1 km$^2$ muon detection area can study muons far from the shower core. IceCube can measure their energy loss ($dE/dx$), and hence their energy. With the energy, and the known distribution of production heights, the transverse momentum ($p_T$) spectrum of high $p_T$ muons can be determined. The production of these muons is calculable in perturbative QCD, so the measured muon spectra can be used to probe the composition of incident cosmic-rays.

Spencer R. Klein

2006-12-02T23:59:59.000Z

248

Observations of the Li, Be, and B isotopes and Constraints on Cosmic-ray Propagation  

SciTech Connect (OSTI)

The abundance of Li, Be, and B isotopes in galactic cosmic rays (GCR) between E=50-200 MeV/nucleon has been observed by the Cosmic Ray Isotope Spectrometer (CRIS) on NASA's ACE mission since 1997 with high statistical accuracy. Precise observations of Li, Be, B can be used to constrain GCR propagation models. We find that a diffusive reacceleration model with parameters that best match CRIS results (e.g. B/C, Li/C, etc) are also consistent with other GCR observations. A {approx}15-20% overproduction of Li and Be in the model predictions is attributed to uncertainties in the production cross-section data. The latter becomes a significant limitation to the study of rare GCR species that are generated predominantly via spallation.

de Nolfo, Georgia A.; Moskalenko, I.V.; Binns, W.R.; Christian, E.R.; Cummings, A.C.; Davis, A.J.; George, J.S.; Hink, P.L.; Israel, M.H.; Leske, R.A.; Lijowski, M.; Mewaldt, R.A.; Stone, E.C.; Strong, A.W.; von Rosenvinge, T.T.; Wiedenbeck, M.E.; Yanasak, N.E.; /NASA, Goddard /Stanford U., HEPL /Washington U., St. Louis /NASA, Headquarters/Caltech, SRL /Aerospace Corp. /Garching, Max Planck Inst., MPE /Caltech, JPL; ,

2006-11-15T23:59:59.000Z

249

THE CENTAURUS A ULTRAHIGH-ENERGY COSMIC-RAY EXCESS AND THE LOCAL EXTRAGALACTIC MAGNETIC FIELD  

SciTech Connect (OSTI)

The ultrahigh-energy cosmic-ray (UHECR) anisotropies discovered by the Pierre Auger Observatory provide the potential to finally address both the particle origins and properties of the nearby extragalactic magnetic field (EGMF). We examine the implications of the excess of {approx}10{sup 20} eV events around the nearby radio galaxy Centaurus A. We find that, if Cen A is the source of these cosmic rays, the angular distribution of events constrains the EGMF strength within several Mpc of the Milky Way to {approx}> 20 nG for an assumed primary proton composition. Our conclusions suggest that either the observed excess is a statistical anomaly or the local EGMF is stronger than conventionally thought. We discuss several implications, including UHECR scattering from more distant sources, time delays from transient sources, and the possibility of using magnetic lensing signatures to attain tighter constraints.

Yueksel, Hasan; Kronberg, Philipp P. [Theoretical Division, MS B285, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Stanev, Todor [Bartol Research Institute, Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Kistler, Matthew D. [Lawrence Berkeley National Laboratory and Department of Physics, University of California, Berkeley, CA 94720 (United States)

2012-10-10T23:59:59.000Z

250

Telescope Array Radar (TARA) observatory for Ultra-High Energy Cosmic Rays  

Science Journals Connector (OSTI)

Abstract Construction was completed during summer 2013 on the Telescope Array \\{RAdar\\} (TARA) bi-static radar observatory for Ultra-High Energy Cosmic Rays (UHECR). TARA is co-located with the Telescope Array, the largest conventional cosmic ray detector in the Northern Hemisphere, in radio-quiet Western Utah. TARA employs an 8MW Effective Radiated Power (ERP) VHF transmitter and smart receiver system based on a 250MS/s data acquisition system in an effort to detect the scatter of sounding radiation by UHECR-induced atmospheric ionization. TARA seeks to demonstrate bi-static radar as a useful new remote sensing technique for UHECRs. In this report, we describe the design and performance of the TARA transmitter and receiver systems.

R. Abbasi; M. Abou Bakr Othman; C. Allen; L. Beard; J. Belz; D. Besson; M. Byrne; B. Farhang-Boroujeny; A. Gardner; W.H. Gillman; W. Hanlon; J. Hanson; C. Jayanthmurthy; S. Kunwar; S.L. Larson; I. Myers; S. Prohira; K. Ratzlaff; P. Sokolsky; H. Takai; G.B. Thomson; D. Von Maluski

2014-01-01T23:59:59.000Z

251

Search for fingerprints of disoriented chiral condensates in cosmic ray showers  

E-Print Network [OSTI]

Although the generation of disoriented chiral condensates (DCCs), where the order parameter for chiral symmetry breaking is misaligned with respect to the vacuum direction in isospin state, is quite natural in the theory of strong interactions, they have so far eluded experiments in accelerators and cosmic rays. If DCCs are formed in high-energy nuclear collisions, the relevant outcome are very large event-by-event fluctuations in the neutral-to-charged pion fraction. In this note we search for fingerprints of DCC formation in observables of ultra-high energy cosmic ray showers. We present simulation results for the depth of the maximum ($X_{max}$) and number of muons on the ground, evaluating their sensitivity to the neutral-to-charged pion fraction asymmetry produced in the primary interaction.

de Almeida, R M; Fraga, E S; Santos, E M

2012-01-01T23:59:59.000Z

252

Search for fingerprints of disoriented chiral condensates in cosmic ray showers  

E-Print Network [OSTI]

Although the generation of disoriented chiral condensates (DCCs), where the order parameter for chiral symmetry breaking is misaligned with respect to the vacuum direction in isospin state, is quite natural in the theory of strong interactions, they have so far eluded experiments in accelerators and cosmic rays. If DCCs are formed in high-energy nuclear collisions, the relevant outcome are very large event-by-event fluctuations in the neutral-to-charged pion fraction. In this note we search for fingerprints of DCC formation in observables of ultra-high energy cosmic ray showers. We present simulation results for the depth of the maximum ($X_{max}$) and number of muons on the ground, evaluating their sensitivity to the neutral-to-charged pion fraction asymmetry produced in the primary interaction.

R. M. de Almeida; J. R. T. de Mello Neto; E. S. Fraga; E. M. Santos

2010-06-11T23:59:59.000Z

253

Remnant Break-up and Muon Production in Cosmic Ray Air Showers  

E-Print Network [OSTI]

We discuss the relation between remnant fragmentation in inelastic high-energy hadronic interactions and muon production in extensive cosmic ray air showers. Using a newly developed tool, a simple and flexible hadronic event generator, we analyze the forward region of hadronic interactions. We show that measurements of the Feynman-x distribution in the beam fragmentation region at LHCf will be key to understanding muon production in air showers quantitatively.

H. J. Drescher

2007-12-10T23:59:59.000Z

254

Cosmic ray modulation studies with Lead-free Gulmarg neutron monitor  

E-Print Network [OSTI]

A lead-free neutron monitor operating at High Altitude Research Laboratory (HARL), Gulmarg optimized for detecting 2.45 MeV neutron bursts produced during the atmospheric lightning discharges is also concurrently used for studying background neutron component present in the atmosphere. These background neutrons are produced due to the interaction of primary cosmic rays with the atmospheric constituents. In order to study and extract the information about the yield of the neutron production during transient atmospheric lightning discharges, the system is continuously operated to monitor and record the cosmic ray produced background secondary neutrons in the atmosphere. The data analysis of the background neutrons recorded by Lead-Free Gulmarg Neutron Monitor (LFGNM) has convincingly established that the modulation effects due to solar activity phenomena compare very well with those monitored by the worldwide IGY or NM64 type neutron monitors which have optimum energy response relatively towards the higher energy regime of the cosmic rays. The data has revealed various types of modulation phenomena like diurnal variation, Forbush decrease etc. during its entire operational period. However, a new kind of a periodic/seasonal variation pattern is also revealed in the data from September 2007 to September 2012, which is seen to be significantly consistent with the data recorded by Emilio Segre observatory, Israel (ESOI) Neutron Monitor. Interestingly, both these neutron monitors have comparable latitude and altitude. However, the same type of consistency is not observed in the data recorded by the other conventional neutron monitors operating across the globe.

M. A. Darzi; P. M. Ishtiaq; T. A. Mir; S. Mufti; G. N. Shah

2013-12-21T23:59:59.000Z

255

Extragalactic cosmic-ray source composition and the interpretation of the ankle  

E-Print Network [OSTI]

We consider the stochastic propagation of high-energy protons and nuclei in the cosmological microwave and infrared backgrounds, using revised photonuclear cross-sections and following primary and secondary nuclei in the full 2D nuclear chart. We confirm earlier results showing that the high-energy data can be fit with a pure proton extragalactic cosmic ray (EGCR) component if the source spectrum is $\\propto E^{-2.6}$. In this case the ankle in the cosmic ray (CR) spectrum may be interpreted as a pair-production dip associated with the propagation. We show that when heavier nuclei are included in the source with a composition similar to that of Galactic cosmic-rays (GCRs), the pair-production dip is not present unless the proton fraction is higher than 85%. In the mixed composition case, the ankle recovers the past interpretation as the transition from GCRs to EGCRs and the highest energy data can be explained by a harder source spectrum $\\propto E^{-2.2}$-- $E^{-2.3}$, reminiscent of relativistic shock acceleration predictions, and in good agreement with the GCR data at low-energy and holistic scenarios. While the expected cosmogenic neutrino fluxes at high energy are very similar for pure proton and mixed composition hypothesis, the two scenarii predict very different elongation rates from $10^{17.5}$ to $10^{20}$ eV.

D. Allard; E. Parizot; A. V. Olinto; E. Khan; S. Goriely

2005-08-22T23:59:59.000Z

256

First cosmic-ray measurements by the SciCRT solar neutron experiment in Mexico  

Science Journals Connector (OSTI)

Abstract The SciBar Cosmic Ray Telescope (SciCRT) is a new multi-purpose cosmic-ray detector. Its main aim is the measurement of solar neutrons to investigate the ion acceleration process during solar flares. We installed the SciCRT at the Instituto Nacional de Astrofisica, ptica y Electrnica (INAOE) in eastern Mexico. We had two cosmic-ray observation campaigns at the place in November 2012 and February 2013 using 5/8 of the complete detector. The detector was transferred to the top of Mt. Sierra Negra, 4600m above sea level, in April 2013. The results obtained at INAOE, and the first experimental result at the mountain are presented in this paper. The counting rates of experimental data and Monte Carlo simulation (MC) are 409.3 ( 0.1)Hz and 395.2 ( 4.8)Hz, respectively. The data and the MC do not show a big discrepancy. The percentages of hadronic shower events in the data and MC are 0.15 ( 0.02 ) % and 0.16 ( 0.03 ) % , respectively. The corresponding percentages of electromagnetic shower events are 0.16 ( 0.02 ) % and 0.18 ( 0.03 ) % . In this case data and MC calculations are in reasonable agreement. The effective area and expected time profile of solar neutrons obtained by the SciCRT are calculated using MC.

Y. Nagai; Y. Matsubara; Y. Itow; T. Sako; D. Lopez; Y. Sasai; T. Itow; K. Munakata; C. Kato; M. Kozai; T. Miyazaki; S. Shibata; H. Takamaru; H. Kojima; H. Tsuchiya; K. Watanabe; T. Koi; J.F. Valds-Galicia; A. Hurtado; O. Musalem; E. Ortiz; L.X. Gonzlez; M. Anzorena; R. Garcia

2014-01-01T23:59:59.000Z

257

Missing cosmic metals revealed by X-ray absorption towards distant sources  

E-Print Network [OSTI]

The census of heavy elements (metals) produced by all stars through cosmic times up to present-day is limited to ~50%; of these only half are still found within their parent galaxy. The majority of metals is expelled from galaxies into the circumgalactic (or even more distant, intergalactic) space by powerful galactic winds, leaving unpleasant uncertainty on the amount, thermal properties and distribution of these key chemical species. These dispersed metals unavoidably absorb soft X-ray photons from distant sources. We show that their integrated contribution can be detected in the form of increasing X-ray absorption with distance, for all kinds of high-energy cosmic sources. Based on extensive cosmological simulations, we assess that $\\sim$ 10\\% of all cosmic metals reside in the intergalactic medium. Most of the X-ray absorption arises instead from a few discrete structures along the line of sight. These extended structures, possibly pin-pointing galaxy groups, contain million degree, metal-enriched gas, 10...

Campana, S; Ferrara, A; Pallottini, A

2015-01-01T23:59:59.000Z

258

Entropy and the Cosmic Ray Particle Energy Distribution Power Law Exponent  

E-Print Network [OSTI]

We consider the hypothesis that cosmic rays are emitted from the surfaces of neutron stars by a process of evaporation from an internal nuclear liquid to a dilute external gas which constitutes the "vacuum". On this basis, we find an inverse power in the energy distribution with a power law exponent of 2.701178 in excellent agreement with the experimental value of 2.7. The heat of nuclear matter evaporation via the entropy allows for the computation of the exponent. The evaporation model employed is based on the entropy considerations of Landau and Fermi that have been applied to the liquid drop model of evaporation in a heavy nucleus excited by a collision. This model provides a new means of obtaining power law distributions for cosmic ray energy distributions and, remarkably, an actual value for the exponent which is in agreement with experiment and explains the otherwise puzzling smoothness of the cosmic ray energy distribution over a wide range of energies without discontinuities due to contributions from different sources required by current models.

A. Widom; J. Swain; Y. N. Srivastava

2014-10-05T23:59:59.000Z

259

Observation of Cosmic-Ray Anisotropy with the IceTop Air Shower Array  

Science Journals Connector (OSTI)

We report on the observation of anisotropy in the arrival direction distribution of cosmic rays at PeV energies. The analysis is based on data taken between 2009 and 2012 with the IceTop air shower array at the south pole. IceTop, an integral part of the IceCube detector, is sensitive to cosmic rays between 100TeV and 1 EeV. With the current size of the IceTop data set, searches for anisotropy at the 103 level can, for the first time, be extended to PeV energies. We divide the data set into two parts with median energies of 400TeV and 2PeV, respectively. In the low energy band, we observe a strong deficit with an angular size of about 30 and an amplitude of ( 1.58 0.46stat 0.52sys) ? 103 at a location consistent with previous observations of cosmic rays with the IceCube neutrino detector. The study of the high energy band shows that the anisotropy persists to PeV energies and increases in amplitude to ( 3.11 0.38stat 0.96sys) ? 103.

M. G. Aartsen; R. Abbasi; Y. Abdou; M. Ackermann; J. Adams; J. A. Aguilar; M. Ahlers; D. Altmann; K. Andeen; J. Auffenberg; X. Bai; M. Baker; S. W. Barwick; V. Baum; R. Bay; K. Beattie; J. J. Beatty; S. Bechet; J. Becker Tjus; K.-H. Becker; M. Bell; M. L. Benabderrahmane; S. BenZvi; J. Berdermann; P. Berghaus; D. Berley; E. Bernardini; D. Bertrand; D. Z. Besson; D. Bindig; M. Bissok; E. Blaufuss; J. Blumenthal; D. J. Boersma; S. Bohaichuk; C. Bohm; D. Bose; S. Bser; O. Botner; L. Brayeur; A. M. Brown; R. Bruijn; J. Brunner; M. Carson; J. Casey; M. Casier; D. Chirkin; B. Christy; K. Clark; F. Clevermann; S. Cohen; D. F. Cowen; A. H. Cruz Silva; M. Danninger; J. Daughhetee; J. C. Davis; C. De Clercq; S. De Ridder; F. Descamps; P. Desiati; G. de Vries-Uiterweerd; T. DeYoung; J. C. Daz-Vlez; J. Dreyer; J. P. Dumm; M. Dunkman; R. Eagan; J. Eisch; R. W. Ellsworth; O. Engdegrd; S. Euler; P. A. Evenson; O. Fadiran; A. R. Fazely; A. Fedynitch; J. Feintzeig; T. Feusels; K. Filimonov; C. Finley; T. Fischer-Wasels; S. Flis; A. Franckowiak; R. Franke; K. Frantzen; T. Fuchs; T. K. Gaisser; J. Gallagher; L. Gerhardt; L. Gladstone; T. Glsenkamp; A. Goldschmidt; G. Golup; J. A. Goodman; D. Gra; D. Grant; A. Gross; S. Grullon; M. Gurtner; C. Ha; A. Haj Ismail; A. Hallgren; F. Halzen; K. Hanson; D. Heereman; P. Heimann; D. Heinen; K. Helbing; R. Hellauer; S. Hickford; G. C. Hill; K. D. Hoffman; R. Hoffmann; A. Homeier; K. Hoshina; W. Huelsnitz; P. O. Hulth; K. Hultqvist; S. Hussain; A. Ishihara; E. Jacobi; J. Jacobsen; G. S. Japaridze; O. Jlelati; A. Kappes; T. Karg; A. Karle; J. Kiryluk; F. Kislat; J. Kls; S. R. Klein; J.-H. Khne; G. Kohnen; H. Kolanoski; L. Kpke; C. Kopper; S. Kopper; D. J. Koskinen; M. Kowalski; M. Krasberg; G. Kroll; J. Kunnen; N. Kurahashi; T. Kuwabara; M. Labare; H. Landsman; M. J. Larson; R. Lauer; M. Lesiak-Bzdak; J. Lnemann; J. Madsen; R. Maruyama; K. Mase; H. S. Matis; F. McNally; K. Meagher; M. Merck; P. Mszros; T. Meures; S. Miarecki; E. Middell; N. Milke; J. Miller; L. Mohrmann; T. Montaruli; R. Morse; R. Nahnhauer; U. Naumann; S. C. Nowicki; D. R. Nygren; A. Obertacke; S. Odrowski; A. Olivas; M. Olivo; A. O'Murchadha; S. Panknin; L. Paul; J. A. Pepper; C. Prez de los Heros; D. Pieloth; N. Pirk; J. Posselt; P. B. Price; G. T. Przybylski; L. Rdel; K. Rawlins; P. Redl; E. Resconi; W. Rhode; M. Ribordy; M. Richman; B. Riedel; J. P. Rodrigues; F. Rothmaier; C. Rott; T. Ruhe; B. Ruzybayev; D. Ryckbosch; S. M. Saba; T. Salameh; H.-G. Sander; M. Santander; S. Sarkar; K. Schatto; M. Scheel; F. Scheriau; T. Schmidt; M. Schmitz; S. Schoenen; S. Schneberg; L. Schnherr; A. Schnwald; A. Schukraft; L. Schulte; O. Schulz; D. Seckel; S. H. Seo; Y. Sestayo; S. Seunarine; C. Sheremata; M. W. E. Smith; M. Soiron; D. Soldin; G. M. Spiczak; C. Spiering; M. Stamatikos; T. Stanev; A. Stasik; T. Stezelberger; R. G. Stokstad; A. Stssl; E. A. Strahler; R. Strm; G. W. Sullivan; H. Taavola; I. Taboada; A. Tamburro; S. Ter-Antonyan; S. Tilav; P. A. Toale; S. Toscano; M. Usner; D. van der Drift; N. van Eijndhoven; A. Van Overloop; J. van Santen; M. Vehring; M. Voge; M. Vraeghe; C. Walck; T. Waldenmaier; M. Wallraff; M. Walter; R. Wasserman; Ch. Weaver; C. Wendt; S. Westerhoff; N. Whitehorn; K. Wiebe; C. H. Wiebusch; D. R. Williams; H. Wissing; M. Wolf; T. R. Wood; K. Woschnagg; C. Xu; D. L. Xu; X. W. Xu; J. P. Yanez; G. Yodh; S. Yoshida; P. Zarzhitsky; J. Ziemann; S. Zierke; A. Zilles; M. Zoll; IceCube Collaboration

2013-01-01T23:59:59.000Z

260

Imaging large vessels using cosmic-ray muon energy-loss techniques  

Science Journals Connector (OSTI)

Imaging the internal structure of large vessels (220m in diameter) is not possible with most traditional imaging methods. The sheer size renders gamma-ray and other high-energy photon, neutron, electrical and acoustic techniques useless, whilst the use of high-energy accelerators required to produce charged-particles of sufficient energy are impractical in most industrial situations. The use of naturally occurring high-energy (?GeV) cosmic-ray mu-mesons (muons) provides an effective solution to the penetration problem. The problems of low intensity at near-horizontal angles with the cosmic-ray muon flux are addressed by using energy-loss imaging methods. In other methodologies, using charge-particle energy-loss imaging techniques, only a few events are needed compared to many thousands required if attenuation measurements were to be employed. The energies of horizontal cosmic-ray muons are distributed largely between 0.1 and 1000GeV with a mean energy of about 50GeV. Radiation Transport Monte-Carlo methods (GEANT4) have been used to calculate the energy loss for a selection of industrial materials in the energy range of interest. The energy loss of the muons along a ray-sum are modelled and compared to attenuation losses along the ray-sum using energy resolving detectors in coincidence before and after the sample. The energy-loss spectra across different samples are measured, demonstrating that embedded materials can be identified with as few as 10 muons passing through the sample. It is proposed that the imaging modality can be extended into a full tomographic modality allowing material identification within each voxel.

P.M. Jenneson; W.B. Gilboy; S.J.R. Simons; S.J. Stanley; D. Rhodes

2007-01-01T23:59:59.000Z

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261

The optical depth of the Universe to ultrahigh energy cosmic ray scattering in the magnetized large scale structure  

E-Print Network [OSTI]

This paper provides an analytical description of the transport of ultrahigh energy cosmic rays in an inhomogeneously magnetized intergalactic medium. This latter is modeled as a collection of magnetized scattering centers such as radio cocoons, magnetized galactic winds, clusters or magnetized filaments of large scale structure, with negligible magnetic fields in between. Magnetic deflection is no longer a continuous process, it is rather dominated by scattering events. We study the interaction between high energy cosmic rays and the scattering agents. We then compute the optical depth of the Universe to cosmic ray scattering and discuss the phenomological consequences for various source scenarios. For typical parameters of the scattering centers, the optical depth is greater than unity at 5x10^{19}eV, but the total angular deflection is smaller than unity. One important consequence of this scenario is the possibility that the last scattering center encountered by a cosmic ray be mistaken with the source of this cosmic ray. In particular, we suggest that part of the correlation recently reported by the Pierre Auger Observatory may be affected by such delusion: this experiment may be observing in part the last scattering surface of ultrahigh energy cosmic rays rather than their source population. Since the optical depth falls rapidly with increasing energy, one should probe the arrival directions of the highest energy events beyond 10^{20}eV on an event by event basis to circumvent this effect.

Kumiko Kotera; Martin Lemoine

2008-04-30T23:59:59.000Z

262

Suzaku Observation of the Fermi Cygnus Cocoon: Search for a Signature of Young Cosmic-Ray Electrons  

E-Print Network [OSTI]

The origin of Galactic cosmic rays remains unconfirmed, but promising candidates for their sources are found in star-forming regions. We report a series of X-ray observations, with Suzaku, toward the nearby star-forming region of Cygnus X. They aim at comparing diffuse X-ray emissions on and off the $\\gamma$-ray cocoon of hard cosmic rays revealed by Fermi LAT. After excluding point sources and small-scale structures and subtracting the non-X-ray and cosmic X-ray backgrounds, the 2--10~keV X-ray intensity distribution is found to monotonically decrease with increasing Galactic latitude. This indicates that most of the extended emission detected by Suzaku originates from the Galactic ridge. In two observations, we derive upper limits of $3.4 \\times 10^{-8}~{\\rm erg~s^{-1}~cm^{-2}~sr^{-1}}$ and $1.3 \\times 10^{-8}~{\\rm erg~s^{-1}~cm^{-2}~sr^{-1}}$ to X-ray emission in the 2--10 keV range from the gamma-ray cocoon. These limits exclude the presence of cosmic-ray electrons with energies above about 50 TeV at a fl...

Mizuno, T; Takahashi, H; Hayashi, K; Yamazaki, R; Grenier, I; Tibaldo, L

2015-01-01T23:59:59.000Z

263

Energy Spectra of Cosmic Rays Accelerated at Ultrarelativistic Shock Waves  

Science Journals Connector (OSTI)

Energy spectra of particles accelerated by the first-order Fermi mechanism are investigated at ultrarelativistic shock waves, outside the range of Lorentz factors considered previously. For particle transport near the shock a numerical method involving small amplitude pitch-angle scattering is applied for flows with Lorentz factors ? from 3 to 243. For large ? shocks a convergence of derived energy spectral indices up to the value ???2.2 is observed for all considered turbulence amplitudes and magnetic field configurations. Recently the same index was derived for ?-ray bursts by Waxman [Astrophys. J. Lett. 485, L5 (1997)].

J. Bednarz and M. Ostrowski

1998-05-04T23:59:59.000Z

264

Are Galactic Gamma-Ray Bursters the Main Source of Hadronic Non-Solar Cosmic Rays at all Energies?  

E-Print Network [OSTI]

We propose a new hypothesis for the origin of non-solar hadronic cosmic rays (CRs) at all energies: Highly relativistic, narrowly collimated jets from the birth or collapse of neutron stars (NSs) in our Galaxy accelerate ambient disk and halo matter to CR energies and disperse it in ``hot spots'' which they form when they stop in the Galactic halo. Such events - ``Galactic Gamma-Ray Bursters'' (GGRBs) - are proposed to cause cosmological gamma-ray bursts (GRBs) in other galaxies when their beamed radiation happens to point in our direction. Our hypothesis naturally explains some observations which are difficult to understand with the currently popular ideas about CR origin - e.g. the small Galacto-centric gradient of the cosmic-ray density and the absence of the Greisen-Zatsepin-Kuzmin cutoff. Our idea stands or falls with the existence of the ``hot spots'' (``GGRB remnants'') in the Galactic halo. We discuss their expected observational signatures and find that they could appear as EGRET unidentified high-latitude sources.

R. Plaga; O. C. de Jager; A. Dar

1999-07-29T23:59:59.000Z

265

Atmospheric Calorimetry above 10$^{19}$ eV: Shooting Lasers at the Pierre Auger Cosmic-Ray Observatory  

E-Print Network [OSTI]

The Pierre Auger Cosmic-Ray Observatory uses the earth's atmosphere as a calorimeter to measure extensive air-showers created by particles of astrophysical origin. Some of these particles carry joules of energy. At these extreme energies, test beams are not available in the conventional sense. Yet understanding the energy response of the observatory is important. For example, the propagation distance of the highest energy cosmic-rays through the cosmic microwave background radiation (CMBR) is predicted to be strong function of energy. This paper will discuss recently reported results from the observatory and the use of calibrated pulsed UV laser "test-beams" that simulate the optical signatures of ultra-high energy cosmic rays. The status of the much larger 200,000 km$^3$ companion detector planned for the northern hemisphere will also be outlined.

L. Wiencke; for the Pierre Auger Collaboration

2008-07-17T23:59:59.000Z

266

The IceCube Collaboration: contributions to the 30th International Cosmic Ray Conference (ICRC 2007)  

E-Print Network [OSTI]

This paper bundles 40 contributions by the IceCube collaboration that were submitted to the 30th International Cosmic Ray Conference ICRC 2007. The articles cover studies on cosmic rays and atmospheric neutrinos, searches for non-localized, extraterrestrial electron, muon and tau neutrino signals, scans for steady and intermittent neutrino point sources, searches for dark matter candidates, magnetic monopoles and other exotic particles, improvements in analysis techniques, as well as future detector extensions. The IceCube observatory will be finalized in 2011 to form a cubic-kilometer ice-Cherenkov detector at the location of the geographic South Pole. At the present state of construction, IceCube consists of 52 paired IceTop surface tanks and 22 IceCube strings with a total of 1426 Digital Optical Modules deployed at depths up to 2350 m. The observatory also integrates the 19 string AMANDA subdetector, that was completed in 2000 and extends IceCube's reach to lower energies. Before the deployment of IceTop, cosmic air showers were registered with the 30 station SPASE-2 surface array. IceCube's low noise Digital Optical Modules are very reliable, show a uniform response and record waveforms of arriving photons that are resolvable with nanosecond precision over a large dynamic range. Data acquisition, reconstruction and simulation software are running in production mode and the analyses, profiting from the improved data quality and increased overall sensitivity, are well under way.

The IceCube Collaboration

2007-11-02T23:59:59.000Z

267

The origin of Cosmic-Rays from SNRs: confirmations and challenges after the first direct proof  

E-Print Network [OSTI]

Until now, providing an experimental unambiguous proof of Cosmic Ray (CR) origin has been elusive. The SuperNova Remnant (SNR) study showed an increasingly complex scenario with a continuous elaboration of theoretical models. The middle-aged supernova remnant (SNR) W44 has recently attracted attention because of its relevance regarding the origin of Galactic cosmic-rays. The gamma-ray missions AGILE and Fermi have established, for the first time for a SNR, the spectral continuum below 200 MeV which can be attributed to neutral pion emission. Our work is focused on a global re-assessment of all available data and models of particle acceleration in W44 and our analysis strengthens previous studies and observations of the W44 complex environment, providing new information for a more detailed modeling. However, having determined the hadronic nature of the gamma-ray emission on firm ground, a number of theoretical challenges remains to be addressed in the context of CR acceleration in SNRs.

Cardillo, M; Giuliani, A

2014-01-01T23:59:59.000Z

268

The Most Likely Sources of High Energy Cosmic-Ray Electrons in Supernova Remnants  

E-Print Network [OSTI]

Evidences of non-thermal X-ray emission and TeV gamma-rays from the supernova remnants (SNRs) has strengthened the hypothesis that primary Galactic cosmic-ray electrons are accelerated in SNRs. High energy electrons lose energy via synchrotron and inverse Compton processes during propagation in the Galaxy. Due to these radiative losses, TeV electrons liberated from SNRs at distances larger than ~1 kpc, or times older than ~10^5 yr, cannot reach the solar system. We investigated the cosmic-ray electron spectrum observed in the solar system using an analytical method, and considered several candidate sources among nearby SNRs which may contribute to the high energy electron flux. Especially, we discuss the effects for the release time from SNRs after the explosion, as well as the deviation of a source spectrum from a simple power-law. From this calculation, we found that some nearby sources such as the Vela, Cygnus Loop, or Monogem could leave unique signatures in the form of identifiable structure in the energ...

Kobayashi, T; Yoshida, K; Nishimura, J

2004-01-01T23:59:59.000Z

269

A stochastic simulation of the propagation of Galactic cosmic rays reflecting the discreteness of cosmic ray sources. Age and path length distribution  

E-Print Network [OSTI]

The path length distribution of Galactic cosmic rays (GCRs) is the fundamental ingredient for modeling the propagation process of GCRs based on the so-called weighted slab method. We try to derive this distribution numerically by taking into account the discreteness in both space and time of occurrences of supernova explosions where GCRs are suspected to be born. We solve numerically the stochastic differential equations equivalent to the Parker diffusion-convection equation which describes the propagation process of GCR in the Galaxy. We assume the three-dimensional diffusion is an isotropic one without any free escape boundaries. We ignore any energy change of GCRs and the existence of the Galactic wind for simplicity. We also assume axisymmetric configurations for the density distributions of the interstellar matter and for the surface density of supernovae. We have calculated age and path length of GCR protons arriving at the solar system with this stochastic method. The obtained age is not the escape tim...

Miyake, S; Yanagita, S

2014-01-01T23:59:59.000Z

270

Cosmic Ray Energy Measurement with EAS Cherenkov Light: Experiment QUEST and CORSIKA Simulation  

E-Print Network [OSTI]

A new method of a primary cosmic particle energy measurement with the extensive air shower (EAS) technique has been developed by exploiting: a) the joint analysis of the shower size, obtained by the EAS-TOP array, and of the EAS Cherenkov light lateral distribution (LDF), obtained by the QUEST array, and b) simulations based on the CORSIKA code. The method is based on the strict correlation between the size/energy ratio and the steepness of the Cherenkov light lateral distribution and has been compared with a "classical" one based on the Cherenkov light flux at a fixed distance (175 m) from the EAS core. The independence of the energy measurement both on the mass of primary particle and the hadronic interaction model used for the analysis is shown. Based on this approach the experimental integral intensity of cosmic rays flux with energy more than 3*10^15 eV is obtained with good systematic and statistical accuracy.

E. E. Korosteleva; L. A. Kuzmichev; V. V. Prosin; EAS-TOP COLLABORATION

2005-11-08T23:59:59.000Z

271

30TH INTERNATIONAL COSMIC RAY CONFERENCE Search for 1-100 GeV Emission from Gamma-Ray Bursts Using Milagro  

E-Print Network [OSTI]

30TH INTERNATIONAL COSMIC RAY CONFERENCE Search for 1-100 GeV Emission from Gamma-Ray Bursts Using one hundred gamma-ray bursts (GRBs) detected since the beginning of 2000 by BATSE, BeppoSax, HETE-2 spectra of gamma-ray bursts peak around a few hundred keV, EGRET has ob- served photons in the GeV energy

California at Santa Cruz, University of

272

29th International Cosmic Ray Conference Pune (2005) 00, 101-104 TeV Observations of EGRET Unidentified Sources  

E-Print Network [OSTI]

29th International Cosmic Ray Conference Pune (2005) 00, 101-104 TeV Observations of EGRET sr), high (>90%) duty factor, TeV gamma-ray observatory is ideal for searching for TeV emission from Milagro has sufficient exposure. Of these 68 sources, 29 are within 10 degrees of the Galactic plane. Te

California at Santa Cruz, University of

273

Solar, geomagnetic and cosmic ray intensity changes, preceding the cyclone appearances around Mexico  

Science Journals Connector (OSTI)

Recently it has been suggested that there exist specific changes in the cosmic ray intensity and some solar and geomagnetic parameters during the days, preceding the hurricane appearances over the North Atlantic Ocean. To understand better these phenomena, data for all hurricanes born not only over the Atlantic but also over the Pacific waters in the last 55 years that hit the Mexican borders were elaborated. As basic hurricane parameters the maximum rotational velocity and the estimated total energy were used. To avoid any interference all hurricanes, overlapping the preceding ones with more than 20 days were not included. Then the behavior of the cosmic ray (CR) intensity, the sunspot (SS) numbers, and the geomagnetic parameters (AP) and (KP) in 35 days prior and 20 days after the cyclone start were investigated. The CR, SS, AP and KP showed much more intensive disturbances in the periods preceding and following the hurricane appearance. For SS this disturbance gradually increase with the hurricane strength. A characteristic peak in the CR intensity appears before the hurricane start. But its place varies between 5 and 20 days before that start. Specific changes were observed in the SS. For major hurricanes they begins sometimes more than 20 days in advance. The AP and the KP show series of bursts, spread over the whole period of 30 preceding days. The obtained results from the performed correlational analysis are enough interesting to motivate a further statistical analysis with more precise techniques: in particular a common periodicity of 30 years found in the number of tropical storms landing into Mexico, the averaged rotational wind velocity and the ACE must be studied in connection with the solar Hale cycle. Using coherence wavelet spectral analysis we present a comparative study between one terrestrial and one cosmophysical phenomena that presumable influence hurricanes development: African dust outbreaks versus cosmic rays for all North Atlantic tropical cyclones. It is shown that the cosmophysical influence cannot be considered as a negligible effect.

J. Prez-Peraza; S. Kavlakov; V. Velasco; A. Gallegos-Cruz; E. Azpra-Romero; O. Delgado-Delgado; F. Villicaa-Cruz

2008-01-01T23:59:59.000Z

274

Cosmic ray propagation and dark matter in light of the latest AMS-02 data  

E-Print Network [OSTI]

The AMS-02 experiment is measuring the high energy charged cosmic rays with unprecedented accuracy. We explore the possibility of determining the cosmic-ray propagation models using the AMS-02 data $alone$. A global Bayesian analysis of the constraints on the cosmic-ray propagation models from the latest AMS-02 data on the Boron to Carbon nuclei flux ratio and proton flux is performed, with the assumption that the primary nucleon source is a broken power law in rigidity. The ratio of the diffusion coefficient $D_{0}$ to the diffusive halo height $Z_{h}$ is found to be determined with high accuracy $D_{0}/Z_{h}\\simeq 2.00\\pm0.07\\text{cm}^{2}\\text{s}^{-1}\\text{kpc}^{-1}$. The best-fit value of the halo width is $Z_{h}\\simeq 3.3$ kpc with uncertainty less than $50\\$. As a consequence, the typical uncertainties in the positron fraction is within a factor of two, and that in the antiproton flux is within an order of magnitude. Both of them are significantly smaller than that from the analyses prior to AMS-02. Taking into account all the uncertainties and correlations in the propagation parameters we derive conservative upper limits on the cross sections for DM annihilating into various standard model final states from the current PAMELA antiproton data. We also investigate the reconstruction capability of the future AMS-02 antiproton data on the DM properties. The result shows that for DM particles lighter than 100 GeV and with typical thermal annihilation cross section, the cross section can be well reconstructed with uncertainties about a factor of two for the AMS-02 three-year data taking.

Hong-Bo Jin; Yue-Liang Wu; Yu-Feng Zhou

2014-10-21T23:59:59.000Z

275

Cosmic rays and the magnetic field of the nearby starburst galaxy NGC 253  

E-Print Network [OSTI]

Using radio polarimetry we study the connection between the transport of cosmic rays (CR's), the three-dimensional magnetic field structure, and features of other ISM phases in the halo of NGC 253. We present a new sensitive radio continuum map of NGC 253 obtained from combined VLA and Effelsberg observations at lambda 6.2 cm. We find a prominent radio halo with a scaleheight of the thick radio disk of 1.7 kpc. The linear dependence between the local scaleheight of the vertical continuum emission and the cosmic ray electron (CRE) lifetime requires a vertical CR bulk speed of 270 km s^-1. The magnetic field structure of NGC 253 resembles an ``X''-shaped configuration where the orientation of the large-scale magnetic field is plane-parallel only in the inner regions of the disk and at small distances from the galactic midplane. At larger galactocentric radii and further away from the midplane the vertical component becomes important. This is most clearly visible at the location of the ``radio spur'' southeast of the nucleus, where the magnetic field orientation is almost vertical. We made a simple model for the dominant toroidal (r,phi) magnetic field component using a spiral magnetic field with prescribed inclination and pitch angle. The residual poloidal (r,phi,z) magnetic field component which was revealed by subtracting the model from the observations shows a distinct ``X''-shaped magnetic field orientation centered on the nucleus. The orientation angle of the poloidal magnetic field is consistent with a magnetic field transport described by the superposition of the vertical CR bulk speed and the rotation velocity. Hence, we propose a disk wind which transports cosmic rays, magnetic field, and (partially) ionized gas from the disk into the halo.

V. Heesen; R. -J. Dettmar; M. Krause; R. Beck

2008-01-23T23:59:59.000Z

276

A Model-Independent Method of Determining Energy Scale and Muon Number in Cosmic Ray Surface Detectors  

E-Print Network [OSTI]

Surface detector arrays are designed to measure the spectrum and composition of high-energy cosmic rays by detecting the secondary particle flux of the Extensive Air Showers (EAS) induced by the primary cosmic rays. Electromagnetic particles and muons constitute the dominant contribution to the ground detector signals. In this paper, we show that the ground signal deposit of an EAS can be described in terms of only very few parameters: the primary energy E, the zenith angle theta, the distance of the shower maximum X_max to the ground, and a muon flux normalization N_mu. This set of physical parameters is sufficient to predict the average particle fluxes at ground level to around 10% accuracy. We show that this is valid for hadronic air showers, using the two standard hadronic interaction models used in cosmic ray physics, QGSJetII and Sibyll, and for primaries from protons to iron. Based on this model, a new approach to calibrating the energy scale of ground array experiments is developed, which factors out the model dependence inherent in such calibrations up to now. Additionally, the method yields a measurement of the average number of muons in EAS. The measured distribution of N_mu of cosmic ray air showers can then be analysed, in conjunction with measurements of X_max from fluorescence detectors, to put constraints on the cosmic ray composition and hadronic interaction models.

Fabian Schmidt; Maximo Ave; Lorenzo Cazon; Aaron Chou

2007-12-21T23:59:59.000Z

277

Solar panels as air Cherenkov detectors for extremely high energy cosmic rays  

E-Print Network [OSTI]

Increasing interest towards the observation of the highest energy cosmic rays has motivated the development of new detection techniques. The properties of the Cherenkov photon pulse emitted in the atmosphere by these very rare particles indicate low-cost semiconductor detectors as good candidates for their optical read-out. The aim of this paper is to evaluate the viability of solar panels for this purpose. The experimental framework resulting from measurements performed with suitably-designed solar cells and large conventional photovoltaic areas is presented. A discussion on the obtained and achievable sensitivities follows.

S. Cecchini; I. D'Antone; L. Degli Esposti; G. Giacomelli; M. Guerra; I. Lax; G. Mandrioli; A. Parretta; A. Sarno; R. Schioppo; M. Sorel; M. Spurio

2000-02-07T23:59:59.000Z

278

The Chicagoland Observatory Underground for Particle Physics cosmic ray veto system  

SciTech Connect (OSTI)

A photomultiplier (PMT) readout system has been designed for use by the cosmic ray veto systems of two warm liquid bubble chambers built at Fermilab by the Chicagoland Observatory Underground for Particle Physics (COUPP) collaboration. The systems are designed to minimize the infrastructure necessary for installation. Up to five PMTs can be daisy-chained on a single data link using standard Category 5 network cable. The cables is also serve distribute to low voltage power. High voltage is generated locally on each PMT base. Analog and digital signal processing is also performed locally. The PMT base and system controller design and performance measurements are presented.

Crisler, M.; Hall, J.; Ramberg, E.; Kiper, T.; /Fermilab

2010-11-01T23:59:59.000Z

279

The Origin of the Knee in the Cosmic-Ray Energy Spectrum  

E-Print Network [OSTI]

A sudden steepening of the cosmic-ray energy spectrum (the knee) is observed at an energy of about 3 PeV (1 PeV = 10$^{15}$eV). The recent results on extensive air showers allow us to conclude that: a) the knee has an astrophysical origin; b) the 'sharpness' and the fine structure of the knee rule out 'Galactic Modulation' as the origin of the knee; c) most likely the knee is the result of the explosion of a single, recent, nearby supernova.

A. D. Erlykin; A. W. Wolfendale

2001-05-20T23:59:59.000Z

280

Galactic cosmic-ray-produced thermoluminescence profiles in meteorites, lunar samples and a terrestrial analog  

Science Journals Connector (OSTI)

The long-term radiation shielding properties of common extraterrestrial materials are poorly known, although these materials are the most likely structural elements on airless worlds such as the Moon. We report on radiation dose profiles in meteorites and lunar soil cores using specific minerals as naturally-occuring dosimeters. We find that radiation profiles are fairly flat in typical meteoroid bodies (< 85 cm radius) and drop by only about 40% through about 2.5 m of lunar soil. These profiles are produced by primary galactic cosmic rays and the secondary proton cascade but with a significant contribution by secondary neutrons at depths of about 2 m (300 g/cm2).

Paul H. Benoit; Yongheng Chen

1996-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "int cosmic ray" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Tidal disruption jets as the source of Ultra-High Energy Cosmic Rays  

E-Print Network [OSTI]

Observations of the spectacular, blazar-like tidal disruption event (TDE) candidates Swift J1644+57 and J2058+05 show that the conditions required for accelerating protons to 10^{20} eV appear to be realized in the outer jet, and possibly in the inner jet as well. Direct and indirect estimates of the rate of jetted-TDEs, and of the energy they inject, are compatible with the observed flux of ultra-high energy cosmic rays (UHECRs) and the abundance of presently contributing sources. Thus TDE-jets can be a major source of UHECRs, even compabile with a pure proton composition.

Farrar, Glennys R

2014-01-01T23:59:59.000Z

282

Calculated Cosmic-Ray Muon Spectra at High Energies (>20 GeV)  

Science Journals Connector (OSTI)

Calculations of sea-level cosmic-ray muon spectra have been made at 75, 80, 85, and 88.75 between 20 and 1000 GeV, and compared with measurements made at Argonne National Laboratory. Although the experimental results are a consistent 60% of the calculated values, leading to too few muons being found at high zenith angles, it is felt that this does not support the Utah anomaly, as the discrepancy is energy- and angle-independent. Similarly, no exotic processes, such as the failure of special relativity, seem to be operating.

Keran O'Brien

1971-08-01T23:59:59.000Z

283

The Multiply Scattering Effect on the Energy Measurement of UHE Cosmic Rays using Atmospheric Fluorescence Technique  

E-Print Network [OSTI]

Point sources in the atmosphere are surrounded by aureole because of atmospheric scattering. The properties of the time-dependent aureole radiance are calculated by use of a Monte Carlo approach and an iterative method. Since the aureole is particularly important in the ultraviolet, which is the region the Ultra-High-Energy (UHE) cosmic ray experiment using the air fluorescence technique like Fly's Eye or High-Resolution-Fly's-Eye(HiRes) are set in. The effect of the multiply scatteing on the energy measurement is studied.

Xingzhi Zhang

2000-04-12T23:59:59.000Z

284

Vibrational excitation induced by electron beam and cosmic rays in normal and superconductive aluminum bars  

E-Print Network [OSTI]

We report new measurements of the acoustic excitation of an Al5056 superconductive bar when hit by an electron beam, in a previously unexplored temperature range, down to 0.35 K. These data, analyzed together with previous results of the RAP experiment obtained for T > 0.54 K, show a vibrational response enhanced by a factor 4.9 with respect to that measured in the normal state. This enhancement explains the anomalous large signals due to cosmic rays previously detected in the NAUTILUS gravitational wave detector.

M. Bassan; B. Buonomo; G. Cavallari; E. Coccia; S. D'Antonio; V. Fafone; L. G. Foggetta; C. Ligi; A. Marini; G. Mazzitelli; G. Modestino; G. Pizzella; L. Quintieri; F. Ronga; P. Valente; S. M. Vinko

2011-08-02T23:59:59.000Z

285

A prototype system for detecting the radio-frequency pulse associated with cosmic ray air showers  

E-Print Network [OSTI]

The development of a system to detect the radio-frequency (RF) pulse associated with extensive air showers of cosmic rays is described. This work was performed at the CASA/MIA array in Utah, with the intention of designing equipment that can be used in conjunction with the Auger Giant Array. A small subset of data (less than 40 out of a total of 600 hours of running time), taken under low-noise conditions, permitted upper limits to be placed on the rate for pulses accompanying showers of energies around $10^{17}$ eV.

Green, K; Suprun, D A; Wilkerson, J F; Green, Kevin; Rosner, Jonathan L.; Suprun, Denis A.

2003-01-01T23:59:59.000Z

286

A prototype system for detecting the radio-frequency pulse associated with cosmic ray air showers  

E-Print Network [OSTI]

The development of a system to detect the radio-frequency (RF) pulse associated with extensive air showers of cosmic rays is described. This work was performed at the CASA/MIA array in Utah, with the intention of designing equipment that can be used in conjunction with the Auger Giant Array. A small subset of data (less than 40 out of a total of 600 hours of running time), taken under low-noise conditions, permitted upper limits to be placed on the rate for pulses accompanying showers of energies around $10^{17}$ eV.

Kevin Green; Jonathan L. Rosner; Denis A. Suprun; J. F. Wilkerson

2003-04-14T23:59:59.000Z

287

Consequences of the common origin of the knee and ankle in Cosmic Ray Physics  

E-Print Network [OSTI]

The differential energy spectrum of the cosmic radiation from solar modulation energies up to 5x10**19 eV is correctly predicted by a recent theory of the knee and ankle which uses only one normalization point. This remarkable quantitative result, spanning over many decades in energy and intensity, along with the existence of the second knee at 6x10**17 eV, is obtained assuming constant spectral indices of individual ions at the cosmic-ray sources and no other critical hypotheses. In this study the chemical composition of the cosmic radiation is evaluated as a direct consequence of the theory. The computed mean logarithmic mass exhibits a rising trend from 1.8 to 3.0 in the range 10**15-10**17 eV, a maximum value of 3.2 at 3x10**17 eV, and a characteristic lightening above 3x10**17 eV up to 4x10**18 eV. All of these distinctive features are in accord with the data of many experiments. Two additional consequences intrinsic to the theory are qualitatively discussed: (1) some limitative bounds on the mechanism a...

Codino, Antonio

2009-01-01T23:59:59.000Z

288

A Numerical Assessment of Cosmic-ray Energy Diffusion through Turbulent Media  

E-Print Network [OSTI]

How and where cosmic rays are produced, and how they diffuse through various turbulent media, represent fundamental problems in astrophysics with far reaching implications, both in terms of our theoretical understanding of high-energy processes in the Milky Way and beyond, and the successful interpretation of space-based and ground based GeV and TeV observations. For example, recent and ongoing detections, e.g., by Fermi (in space) and HESS (in Namibia), of $\\gamma$-rays produced in regions of dense molecular gas hold important clues for both processes. In this paper, we carry out a comprehensive numerical investigation of relativistic particle acceleration and transport through turbulent magnetized environments in order to derive broadly useful scaling laws for the energy diffusion coefficients.

Fatuzzo, Marco

2014-01-01T23:59:59.000Z

289

UHE nuclei propagation and the interpretation of the ankle in the cosmic-ray spectrum  

E-Print Network [OSTI]

We consider the stochastic propagation of high-energy protons and nuclei in the cosmological microwave and infrared backgrounds, using revised photonuclear cross-sections and following primary and secondary nuclei in the full 2D nuclear chart. We confirm earlier results showing that the high-energy data can be fit with a pure proton extragalactic cosmic ray (EGCR) component if the source spectrum is \\propto E^{-2.6}. In this case the ankle in the CR spectrum may be interpreted as a pair-production dip associated with the propagation. We show that when heavier nuclei are included in the source with a composition similar to that of Galactic cosmic-rays (GCRs), the pair-production dip is not present unless the proton fraction is higher than 85%. In the mixed composition case, the ankle recovers the past interpretation as the transition from GCRs to EGCRs and the highest energy data can be explained by a harder source spectrum \\propto E^{-2.2} - E^{-2.3}, reminiscent of relativistic shock acceleration predictions, and in good agreement with the GCR data at low-energy and holistic scenarios.

D. Allard; E. Parizot; E. Khan; S. Goriely; A. V. Olinto

2005-06-04T23:59:59.000Z

290

Baryon Production at LHC and Very High Energy Cosmic Ray Spectra  

E-Print Network [OSTI]

The spectra of baryons at LHC can explain the features of the proton spectra in cosmic rays (CR). It seems important to study all baryon data that are available from collider experiments in wide range of energies. Transverse momentum spectra of baryons from RHIC ($\\sqrt(s)$=62 and 200 GeV) and from LHC ($\\sqrt(s)$=0.9 and 7 TeV) have been considered. It is seen that the slope of distributions at low $p_T$'s is changing with energy. The QGSM fit of these spectra gives the average transverse momenta which behave as $s^{0.06}$ that is similar to the previously observed behavior of $\\Lambda^0$ hyperon spectra. The change in average transverse momenta that are slowly growing in VHE hadron interactions at CR detectors cannot cause the "knee" in measured cosmic ray proton spectra. In addition, the available data on heavy quark hadron production from LHC-b at $\\sqrt{s}$=7 TeV were also studied. The preliminary dependence of hadron average transverse momenta on their masses at LHC energy is presented. The possible sou...

Piskounova, Olga I

2015-01-01T23:59:59.000Z

291

Processing of formic acid-containing ice by heavy and energetic cosmic ray analogues  

E-Print Network [OSTI]

Formic acid (HCOOH) has been extensively detected in space environments, including interstellar medium (gas and grains), comets and meteorites. Such environments are often subjected to the action of ionizing agents, which may cause changes in the molecular structure, thus leading to formation of new species. Formic acid is a possible precursor of pre-biotic species, such as Glycine (NH2CH2COOH). This work investigates experimentally the physicochemical effects resulting from interaction of heavy and energetic cosmic ray analogues (46MeV 58Ni11+) in H2O:HCOOH (1:1) ice, at 15 K, in ultrahigh vacuum regime, using Fourier transform infrared spectrometry in the mid-infrared region (4000-600 cm-1 or 2.5-12.5 microns). After the bombardment, the sample was slowly heated to room temperature. The results show the dissociation cross-section for the formic acid of 2.4x10^-13 cm2, and half-life due to galactic cosmic rays of 8x10^7 yr. The IR spectra show intense formation of CO and CO2, and small production of more com...

Bergantini, A; Rothard, H; Boduch, P; Andrade, D P P

2014-01-01T23:59:59.000Z

292

Pinning down the cosmic ray source mechanism with new IceCube data  

Science Journals Connector (OSTI)

Very recently the IceCube Collaboration has reported an observation of 28 neutrino candidates with energies between 50TeV and 2PeV, constituting a 4.1? excess compared to the atmospheric background. In this article we investigate the compatibility between the data and a hypothesized unbroken power-law neutrino spectrum for various values of spectral index ??2. We show that ??2.3 is consistent at the ?1.5? level with the observed events up to 2PeV and to the null observation of events at higher energies. We then assume that the sources of this unbroken spectrum are Galactic, and deduce (i)an energy-transfer fraction from parent protons to pions (finding ?? and ??), and (ii)a way of discriminating among models which have been put forth to explain the knee and ankle features of the cosmic ray spectrum. Future IceCube data will test the unbroken power-law hypothesis and provide a multimessenger approach to explaining features of the cosmic ray spectrum, including the transition from Galactic to extragalactic dominance.

Luis A. Anchordoqui; Haim Goldberg; Morgan H. Lynch; Angela V. Olinto; Thomas C. Paul; Thomas J. Weiler

2014-04-04T23:59:59.000Z

293

DETECTION OF THE COSMIC {gamma}-RAY HORIZON FROM MULTIWAVELENGTH OBSERVATIONS OF BLAZARS  

SciTech Connect (OSTI)

The first statistically significant detection of the cosmic {gamma}-ray horizon (CGRH) that is independent of any extragalactic background light (EBL) model is presented. The CGRH is a fundamental quantity in cosmology. It gives an estimate of the opacity of the universe to very high energy (VHE) {gamma}-ray photons due to photon-photon pair production with the EBL. The only estimations of the CGRH to date are predictions from EBL models and lower limits from {gamma}-ray observations of cosmological blazars and {gamma}-ray bursts. Here, we present homogeneous synchrotron/synchrotron self-Compton (SSC) models of the spectral energy distributions of 15 blazars based on (almost) simultaneous observations from radio up to the highest energy {gamma}-rays taken with the Fermi satellite. These synchrotron/SSC models predict the unattenuated VHE fluxes, which are compared with the observations by imaging atmospheric Cherenkov telescopes. This comparison provides an estimate of the optical depth of the EBL, which allows us a derivation of the CGRH through a maximum likelihood analysis that is EBL-model independent. We find that the observed CGRH is compatible with the current knowledge of the EBL.

Dominguez, A.; Siana, B. [Department of Physics and Astronomy, University of California, Riverside, CA 92521 (United States); Finke, J. D. [U.S. Naval Research Laboratory, Space Science Division, Code 7653, 4555 Overlook Avenue SW, Washington, DC 20375 (United States); Prada, F. [Campus of International Excellence UAM-CSIC, Cantoblanco, E-28049 Madrid (Spain); Primack, J. R. [Department of Physics, University of California, Santa Cruz, CA 95064 (United States); Kitaura, F. S. [Leibniz-Institut fuer Astrophysik (AIP), An der Sternwarte 16, D-14482 Potsdam (Germany); Paneque, D., E-mail: albertod@ucr.edu [Kavli Institute for Particle Astrophysics and Cosmology, SLAC, Stanford University, Stanford, CA 94305 (United States)

2013-06-10T23:59:59.000Z

294

The Pierre Auger Observatory scaler mode for the study of solar activity modulation of galactic cosmic rays  

SciTech Connect (OSTI)

Since data-taking began in January 2004, the Pierre Auger Observatory has been recording the count rates of low energy secondary cosmic ray particles for the self-calibration of the ground detectors of its surface detector array. After correcting for atmospheric effects, modulations of galactic cosmic rays due to solar activity and transient events are observed. Temporal variations related with the activity of the heliosphere can be determined with high accuracy due to the high total count rates. In this study, the available data are presented together with an analysis focused on the observation of Forbush decreases, where a strong correlation with neutron monitor data is found.

Abreu, P.; /Lisbon, LIFEP /Lisbon, IST; Aglietta, M.; /Turin Observ. /Turin U. /INFN, Turin; Ahn, E.J.; /Fermilab; Allard, D.; /APC, Paris; Allekotte, I.; /Centro Atomico Bariloche /Balseiro Inst., San Carlos de Bariloche; Allen, J.; /New York U.; Alvarez Castillo, J.; /Mexico U.; Alvarez-Muniz, J.; /Santiago de Compostela U.; Ambrosio, M.; /Naples U. /INFN, Naples; Aminaei, A.; /Nijmegen U., IMAPP; Anchordoqui, L.; /Wisconsin U., Milwaukee /Lisbon, LIFEP /Lisbon, IST

2011-01-01T23:59:59.000Z

295

Reply to comment by N. D. Marsh and H. Svensmark on ``Solar influences on cosmic rays and cloud formation: A reassessment''  

E-Print Network [OSTI]

Reply to comment by N. D. Marsh and H. Svensmark on ``Solar influences on cosmic rays and cloud System Research Center, Department of Geosciences, University of Massachusetts, Amherst, Massachusetts on ``Solar influences on cosmic rays and cloud formation: A reassessment,'' J. Geophys. Res., 109, D14206

Bradley, Raymond S.

296

Observations of cosmic gamma ray sources and their contribution to the diffuse gamma ray background  

SciTech Connect (OSTI)

The objective is to study soft gamma ray emission in the 0.1 to 10 MeV energy band for selected active galactic nuclei and explore how much they contribute to the total diffuse gamma ray background. A series of imaging observations of extragalactic objects in the low energy gamma-ray region were carried out by the Coded Aperture Directional Gamma-ray Telescope (DGT). The DGT was successfully flown at stratospheric balloon altitudes, and observations were made of the Crab, NGC 1275, MKN 421, and NGC 4151. The measured Crab spectrum is consistent with a featureless power-law of the form. Significant emission was detected up to 500 keV from the Seyfert galaxy, NGC 4151. To increase the total sky exposure the extragalactic field images were analyzed, including the 3C 273 region, obtained by the DGT.

Bhattacharya, D.

1990-01-01T23:59:59.000Z

297

Violation of the Greisen-Zatsepin-Kuzmin Cutoff: A Tempest in a (Magnetic) Teapot? Why Cosmic Ray Energies above 1020 eV May Not Require New Physics  

Science Journals Connector (OSTI)

The apparent lack of suitable astrophysical sources for the observed highest energy cosmic rays within ?20 Mpc is the Greisen-Zatsepin-Kuzmin (GZK) paradox. We constrain representative models of the extragalactic magnetic field structure by Faraday rotation measurements; limits are at the ?G level rather than the nG level usually assumed. In such fields, even the highest energy cosmic rays experience large deflections. This allows nearby active galactic nuclei (possibly quiet today) or gamma ray bursts to be the source of ultrahigh energy cosmic rays without contradicting the GZK distance limit.

Glennys R. Farrar and Tsvi Piran

2000-04-17T23:59:59.000Z

298

Fast Neutron - Mirror Neutron Oscillation and Ultra High Energy Cosmic Rays  

E-Print Network [OSTI]

If there exists the mirror world, a parallel hidden sector of particles with exactly the same microphysics as that of the observable particles, then the primordial nucleosynthesis constraints require that the temperature of the cosmic background of mirror relic photons should be smaller than that of the ordinary relic photons, T'/T neutron - mirror neutron oscillation in vacuum, with an oscillation time $\\tau \\sim 1$ s, much smaller than the neutron lifetime. We show that this could provide a very efficient mechanism for transporting ultra high energy protons at large cosmological distances. The mechanism operates as follows: a super-GZK energy proton scatters a relic photon producing a neutron that oscillates into a mirror neutron which then decays into a mirror proton. The latter undergoes a symmetric process, scattering a mirror relic photon and producing back an ordinary nucleon, but only after traveling a distance $(T/T')^{3}$ times larger than ordinary protons. This may relax or completely remove the GZK-cutoff in the cosmic ray spectrum and also explain the correlation between the observed ultra high energy protons and far distant sources as are the BL Lacs.

Zurab Berezhiani; Luis Bento

2006-02-24T23:59:59.000Z

299

Quark-gluon state of matter and positive excess of cosmic-ray muons at high energies  

Science Journals Connector (OSTI)

The problem of the relationship between the numbers of positively and negatively charged particles in the flux of cosmic-ray muons arriving at sea level with energies in excess of 0.1 TeV (up ... quarkgluon matt...

L. V. Volkova; G. T. Zatsepin

2008-10-01T23:59:59.000Z

300

Measurements of the energy spectrum of cosmic-ray muons at sea-level with emulsion chambers  

Science Journals Connector (OSTI)

The energy spectrum of cosmic-ray muons at sea-level has been measured in the energy range of 1 TeV to 10 TeV ... tons of lead/year. On the vertical muon intensity, it is shown that the index ... law. The zenith ...

K. Mizutani; A. Misaki; T. Shirai; Z. Watanabe; M. Akashi

1978-01-21T23:59:59.000Z

Note: This page contains sample records for the topic "int cosmic ray" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

30TH INTERNATIONAL COSMIC RAY CONFERENCE Atmospheric Monitoring with a LIDAR and an Infra-red Camera at Black Rock  

E-Print Network [OSTI]

density, the US atmospheric standard model is used so far, and a radio sonde data is also used COLLABORATION 1 Department of Physics, Kinki University 2 Graduate School of Science, Osaka City University 3 for cosmic rays experiment. The aims of atmospheric moni- toring are to calibrate observed energy

302

Abstract--The Cosmic Ray Observatory Project (CROP) at University of Nebraska/Lincoln and the Washington Area Large-  

E-Print Network [OSTI]

developed to collect and synchronize the data from each detector site. The cost for each card is under US October 29, 2003. This work was supported in part by the U.S. Department of Energy, Quarknet, and the U.S several outreach projects siting cosmic-ray detectors at local high schools in cities around North America

Berns, Hans-Gerd

303

Lithium generated by cosmic rays: an estimator of the time that Mars had a thicker atmosphere and liquid water  

E-Print Network [OSTI]

Lithium is overabundant in cosmic rays because protons impact on carbon and oxygen nuclei and fission them. Among the products of this fission is lithium. Given this preference for carbon and oxygen atoms, in this work I propose that in an atmosphere of almost pure CO2, such as Mars and Venus atmospheres, lithium nuclei are produced by interaction with cosmic rays. I calculated the production rate of lithium and came to the conclusion that, for pressures of two bars or greater, are produced between 21 and 81 lithium nuclei for each primary cosmic rays proton. For lower pressures, the production is less and almost nil with the current pressure of Mars or Earth (pressure of CO2). Assuming a rate of cosmic ray arrival at Mars equal to that of Earth, and a pressure greater than two bars throughout the history of Mars, the amount of lithium that would occur would be between 162 and 642 million metric tons (in the Earth lithium estimated reserves are 30 million metric tons). These values are an upper limit; the act...

Durand-Manterola, Hector Javier

2012-01-01T23:59:59.000Z

304

Cosmic Rays around $10^{18} $eV: Implications of Contemporary Measurements on the Origin of the Ankle Feature  

E-Print Network [OSTI]

The impressive power-law decay of the energy spectrum of cosmic rays over more than thirty orders of magnitude in intensity and for energies ranging over eleven decades between $\\simeq 10^9 $eV and $\\simeq 10^{20} $eV is actually dotted with small irregularities. These irregularities are highly valuable for uncovering and understanding the modes of production and propagation of cosmic rays. They manifest themselves through changes in the spectral index characterising the observed power laws. One of these irregularities, known as the \\textit{ankle}, is subject to conflicting interpretations for many years. If contemporary observations characterising it have shed new lights, they are still far from being able to deliver all the story. The purpose of this contribution is to give an overview of the physics of cosmic rays in the energy range where the transition between Galactic and extragalactic cosmic rays is expected to occur, and to deliver several lines of thought about the origin of the ankle.

Deligny, Olivier

2014-01-01T23:59:59.000Z

305

arXiv:0706.1749v1[astro-ph]12Jun2007 30th International Cosmic Ray Conference  

E-Print Network [OSTI]

¨ue, Argentina 1 Depto de F´isica, Centro At´omico Bariloche, CNEA and CONICET, Argentina mollerach@cab.cnea.gov.ar Abstract: If clustering of the arrival directions of ultra high energy cosmic rays is discovered Auger Observatory as a function of the angular scale and the energy threshold. We compare our results

306

Measurement of the Flux of Ultrahigh Energy Cosmic Rays from Monocular Observations by the High Resolution Fly's Eye  

E-Print Network [OSTI]

of Physics and Nevis Laboratory, New York, New York, USA 6) University of New Mexico, Department of PhysicsMeasurement of the Flux of Ultrahigh Energy Cosmic Rays from Monocular Observations by the High of Utah, Department of Physics and High Energy Astrophysics Institute, Salt Lake City, Utah, USA 2

307

1. Blandford, R. Particle acceleration at astrophysical shocks: A theory of cosmic ray origin [Text] / R. Blandford,  

E-Print Network [OSTI]

-wavelength mode instability [Text] / A.M. Bykov, S.M. Osipov, D.C. Ellison // Monthly Notices Royal Astronomical Society. ­ 2011. ­ Vol. 410. ­ P. 39­52. 4. Shapiro, V.D. Non-resonant firehose instability: Consequences for the theory of cosmic ray acceleration [Text] / V.D. Shapiro, K.B. Quest, M. Okolicsanyi

308

Physics from the Very-High Energy Cosmic-Ray Shadows of the Moon and Sun with Milagro  

E-Print Network [OSTI]

stringent upper limit at TeV energies. iv #12;The Milagro-measured solar shadow probes the Sun's magneticPhysics from the Very-High Energy Cosmic-Ray Shadows of the Moon and Sun with Milagro by Grant E Los Alamos New Mexico, which operated from 2000-2008. With continuous operation and a large field

California at Santa Cruz, University of

309

Probing the Climatological Impact of a Cosmic Ray-Cloud Connection through Low-Frequency Radio Observations  

E-Print Network [OSTI]

It has been proposed that cosmic ray events could have a causal relationship with cloud formation rates. Given the weak constraints on the role that cloud formation plays in climate forcing it is essential to understand the role such a relationship could have in shaping the Earth's climate. This issue has been previously investigated in the context of the long-term effect of cosmic ray events on climate. However, in order to establish whether or not such a relationship exists, measurements of short-timescale solar events, individual cosmic ray events, and spatially correlated cloud parameters could be of great significance. Here we propose such a comparison using observations from a pair of radio telescopes arrays, the Long Wavelength Array (LWA) and the Eight-meter-wavelength Transient Array (ETA). These low-frequency radio arrays have a unique ability to simultaneously conduct solar, ionospheric and cosmic rays observations and are thus ideal for such a comparison. We will outline plans for a comparison usi...

Magee, Nathan

2011-01-01T23:59:59.000Z

310

30TH INTERNATIONAL COSMIC RAY CONFERENCE CHERCAM: the Cherenkov imager of the CREAM experiment, results in Z=1 test  

E-Print Network [OSTI]

the high energy spectrum of nuclear elements from H to Fe in the cosmic ray flux up to ½¼½ e in this energy domain. The individual nuclear elements separation will allow to probe the current models Instituto de Fisica, UNAM, Mexico Michel.Buenerd@lpsc.in2p3.fr Abstract: The CREAM experiment investigates

Paris-Sud XI, Université de

311

AMS-02 data confront acceleration of cosmic ray secondaries in nearby sources  

Science Journals Connector (OSTI)

We revisit the model proposed earlier to account for the observed increase in the positron fraction in cosmic rays with increasing energy, in the light of new data from the Alpha Magnetic Spectrometer (AMS-02) experiment. The model accounts for the production and acceleration of secondary electrons and positrons in nearby supernova remnants which results in an additional, harder component that becomes dominant at high energies. By fitting this to AMS-02 data we can calculate the expected concomitant rise of the boron-to-carbon ratio, as well as of the fraction of antiprotons. If these predictions are confirmed by the forthcoming AMS-02 data it would conclusively rule out all other proposed explanations, in particular, dark matter annihilations or decays.

Philipp Mertsch and Subir Sarkar

2014-09-09T23:59:59.000Z

312

AMS-02 Results Support the Secondary Origin of Cosmic Ray Positrons  

Science Journals Connector (OSTI)

We show that the recent AMS-02 positron fraction measurement is consistent with a secondary origin for positrons and does not require additional primary sources such as pulsars or dark matter. The measured positron fraction at high energy saturates the previously predicted upper bound for secondary production, obtained by neglecting radiative losses. This coincidence, which will be further tested by upcoming AMS-02 data at higher energy, is a compelling indication for a secondary source. Within the secondary model, the AMS-02 data imply a cosmic ray propagation time in the Galaxy of <106??yr and an average traversed interstellar matter density of ?1??cm-3, comparable to the density of the Milky Way gaseous disk, at a rigidity of 300GV.

Kfir Blum; Boaz Katz; Eli Waxman

2013-11-20T23:59:59.000Z

313

A comprehensive comparison for simulations of cosmic-ray muons underground  

SciTech Connect (OSTI)

The two leading simulation frameworks used for the simulation of cosmic-ray muons underground are FLUKA and Geant4. There have been in the past various questions raised as to the equivalence of these codes regarding cosmogenically produced neutrons and radioactivity in an underground environment. Many experiments choose one of these frameworks, and because they typically have different geometries or locations, the issues relating to code comparison are compounded. We report on an effort to compare the results of each of these codes in simulations which have simple geometry that is consistent between the two codes. It is seen that in terms of integrated neutron flux and neturon capture statistics the codes agree well in a broad sense. There are, however, differences that will be subject of further study. Comparisons of the simulations to available data are considered and the difficulties of such comparisons are pointed out.

Villano, A. N.; Cushman, P.; Kennedy, A. [University of Minnesota, Minneapolis MN 55455 (United States)] [University of Minnesota, Minneapolis MN 55455 (United States); Empl, A.; Lindsay, S. [University of Arkansas at Little Rock, Little Rock AR 72204 (United States)] [University of Arkansas at Little Rock, Little Rock AR 72204 (United States)

2013-08-08T23:59:59.000Z

314

The importance of muon information on primary mass discrimination of ultra-high energy cosmic rays  

E-Print Network [OSTI]

Several methods can be used to perform statistical inference of primary composition of cosmic rays measured with water Cerenkov detectors as those in use at the Pierre Auger Southern Observatory. In the present work we assess the impact of additional information about the number of muons in the air shower, on the problem of statistical primary mass discrimination. Several tools are studied, including neural networks, principal component analysis and traditional methods in current use in the field. For our case study we use hypothetical plastic scintillators as muon counters, buried at the side and outside the shade of the water Cerenkov tanks. The study is extended to protons and Fe nuclei impinging on an array with two different spacings, 750 and 1500 m and, therefore, suitable to the 1-10 EeV energy range. A prototype of such a detector is under construction.

D. Supanitsky; A. Tiba; G. Medina-Tanco; A. Etchegoyen; I. Allekotte; M. Gomez Berisso; V. de Souza; C. Medina; J. A. Ortiz; R. Shellard

2005-10-14T23:59:59.000Z

315

Studies of Cosmic Ray Composition and Air Shower Structure with the Pierre Auger Observatory  

SciTech Connect (OSTI)

These are presentations to be presented at the 31st International Cosmic Ray Conference, in Lodz, Poland during July 2009. It consists of the following presentations: (1) Measurement of the average depth of shower maximum and its fluctuations with the Pierre Auger Observatory; (2) Study of the nuclear mass composition of UHECR with the surface detectors of the Pierre Auger Observatory; (3) Comparison of data from the Pierre Auger Observatory with predictions from air shower simulations: testing models of hadronic interactions; (4) A Monte Carlo exploration of methods to determine the UHECR composition with the Pierre Auger Observatory; (5) The delay of the start-time measured with the Pierre Auger Observatory for inclined showers and a comparison of its variance with models; (6) UHE neutrino signatures in the surface detector of the Pierre Auger Observatory; and (7) The electromagnetic component of inclined air showers at the Pierre Auger Observatory.

Abraham, : J.; Abreu, P.; Aglietta, M.; Aguirre, C.; Ahn, E.J.; Allard, D.; Allekotte, I.; Allen, J.; Alvarez-Muniz, J.; Ambrosio, M.; Anchordoqui, L.

2009-06-01T23:59:59.000Z

316

Performances of linseed oil-free bakelite RPC prototypes with cosmic ray muons  

E-Print Network [OSTI]

A comparative study has been performed on Resistive Plate Chambers (RPC) made of two different grades of bakelite paper laminates, produced and commercially available in India. The chambers, operated in the streamer mode using argon, tetrafluroethane and isobutane in 34:59:7 mixing ratio, are tested for the efficiency and the stability with cosmic rays. A particular grade of bakelite (P-120, NEMA LI-1989 Grade XXX), used for high voltage insulation in humid conditions, was found to give satisfactory performance with stable efficiency of > 96% continuously for more than 130 days. A thin coating of silicone fluid on the inner surfaces of the bakelite RPC is found to be necessary for operation of the detector.

Biswas, S; Bose, S; Chattopadhyay, S; Saha, S; Sharan, M K; Viyogi, Y P

2009-01-01T23:59:59.000Z

317

Cosmic-Ray-Induced Ship-Effect Neutron Measurements and Implications for Cargo Scanning at Borders  

SciTech Connect (OSTI)

Neutron measurements are used as part of the interdiction process for illicit nuclear materials at border crossings. Even though the natural neutron background is small, its variation can impact the sensitivity of detection systems. The natural background of neutrons that is observed in monitoring instruments arises almost entirely from cosmic ray induced cascades in the atmosphere and the surrounding environment. One significant source of variation in the observed neutron background is produced by the ship effect in large quantities of cargo that transit past detection instruments. This paper reports on results from measurements with typical monitoring equipment of ship effect neutrons in various materials. One new result is the neutron shadow shielding effect seen with some low neutron density materials.

Kouzes, Richard T.; Ely, James H.; Seifert, Allen; Siciliano, Edward R.; Weier, Dennis R.; Windsor, Lindsay K.; Woodring, Mitchell L.; Borgardt, James D.; Buckley, Elise D.; Flumerfelt, Eric L.; Oliveri, Anna F.; Salvitti, Matthew

2008-03-11T23:59:59.000Z

318

Cosmic Ray Muon Flux at the Sanford Underground Laboratory at Homestake  

E-Print Network [OSTI]

Measuring the muon flux is important to the Sanford Underground Laboratory at Homestake, for which several low background experiments are being planned. The nearly-vertical cosmic ray muon flux was measured in three locations at this laboratory: on the surface (1.149 \\pm 0.017 x 10^-2 cm^-2 s^-1 sr^-1), at the 800-ft (0.712 km w.e.) level (2.67 \\pm 0.06 x 10^-6 cm^-2 s^-1 sr^-1), and at the 2000-ft (1.78 km w.e.) level (2.56 \\pm 0.25 x 10^-7 cm^-2 s^-1 sr^-1). These fluxes agree well with model predictions.

F. E. Gray; C. Ruybal; J. Totushek; D. -M. Mei; K. Thomas; C. Zhang

2010-07-12T23:59:59.000Z

319

Assessing the Feasibility of Interrogating Nuclear Waste Storage Silos using Cosmic-ray Muons  

E-Print Network [OSTI]

Muon radiography is a fast growing field in applied scientific research. In recent years, many detector technologies and imaging techniques using the Coulomb scattering and absorption properties of cosmic-ray muons have been developed for the non-destructive assay of various structures across a wide range of applications. This work presents the first results that assess the feasibility of using muons to interrogate waste silos within the UK Nuclear Industry. Two such approaches, using different techniques that exploit each of these properties, have previously been published, and show promising results from both simulation and experimental data for the detection of shielded high-Z materials and density variations from volcanic assay. Both detector systems are based on scintillator and photomultiplier technologies. Results from dedicated simulation studies using both these technologies and image reconstruction techniques are presented for an intermediate-sized nuclear waste storage facility filled with concrete...

Ambrosino, F; Cimmino, L; D'Alessandro, R; Ireland, D G; Kaiser, R; Mahon, D F; Mori, N; Noli, P; Saracino, G; Shearer, C; Viliani, L; Yang, G

2014-01-01T23:59:59.000Z

320

Simulations of reflected radio signals from cosmic ray induced air showers  

E-Print Network [OSTI]

We present the calculation of coherent radio pulses emitted by extensive air showers induced by ultra-high energy cosmic rays accounting for reflection on the Earth's surface. Results have been obtained with a simulation program that calculates the contributions from shower particles after reflection at a surface plane. The properties of the radiation are discussed in detail emphasizing the effects of reflection. The shape of the frequency spectrum is shown to be closely related to the angle of the observer with respect to shower axis, becoming hardest in the Cherenkov direction. The intensity of the flux at a fixed observation angle is shown to scale with the square of the primary particle energy to very good accuracy indicating the coherent aspect of the emission. The simulation methods of this paper provide the foundations for energy reconstruction of experiments looking at the Earth from balloons and satellites. They can also be used in dedicated studies of existing and future experimental proposals.

Alvarez-Muiz, Jaime; Garca-Fernndez, Daniel; Schoorlemmer, Harm; Zas, Enrique

2015-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "int cosmic ray" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Energy Spectrum of Fast Cosmic-Ray Neutrons near Sea Level  

Science Journals Connector (OSTI)

Measurement of the sea-level spectrum of cosmic-ray neutrons in the energy region 0.05-2.0 MeV has been carried out with 4? hydrogen-recoil proportional counters. Electronic pulse-shape discrimination has been utilized to reject meson- and photon-induced events. In general, the flux per unit energy decreases monotonically with increasing energy. The experimental data reveal some structure which may be due to scattering resonances in elements that dominate the environment. An integral flux of 2.310-3 neutrons/cm2 sec in the interval 0.05-2.0 MeV has been obtained for the air-land interface at the Argonne National Laboratory site (53 N geomagnetic latitude).

Raymond Gold

1968-01-25T23:59:59.000Z

322

Feynman scaling violation on baryon spectra in pp collisions at LHC and cosmic ray energies  

SciTech Connect (OSTI)

A significant asymmetry in baryon/antibaryon yields in the central region of high energy collisions is observed when the initial state has nonzero baryon charge. This asymmetry is connected with the possibility of baryon charge diffusion in rapidity space. Such a diffusion should decrease the baryon charge in the fragmentation region and translate into the corresponding decrease of the multiplicity of leading baryons. As a result, a new mechanism for Feynman scaling violation in the fragmentation region is obtained. Another numerically more significant reason for the Feynman scaling violation comes from the fact that the average number of cut Pomerons increases with initial energy. We present the quantitative predictions of the Quark-Gluon String Model for the Feynman scaling violation at LHC energies and at even higher energies that can be important for cosmic ray physics.

Arakelyan, G. H., E-mail: argev@mail.yerphi.am [Yerevan Physics Institute, A.I. Alikhanyan National Science Laboratory (Armenia); Merino, C., E-mail: merino@fpaxp1.usc.es; Pajares, C., E-mail: pajares@fpaxp1.usc.es [Departamento de Fisica de Part iculas and Instituto Galego de Fisica de Altas Enerx ias Universidade de Santiago de Compostela (Spain); Shabelski, Yu. M., E-mail: shabelsk@thd.pnpi.spb.ru [RAS, Gatchina, NRC Kurchatov Institute, Petersburg Nuclear Physics Institute (Russian Federation)

2013-03-15T23:59:59.000Z

323

Observation of the cosmic-ray shadow of the Moon with IceCube  

Science Journals Connector (OSTI)

We report on the observation of a significant deficit of cosmic rays from the direction of the Moon with the IceCube detector. The study of this Moon shadow is used to characterize the angular resolution and absolute pointing capabilities of the detector. The detection is based on data taken in two periods before the completion of the detector: between April 2008 and May 2009, when IceCube operated in a partial configuration with 40 detector strings deployed in the South Pole ice, and between May 2009 and May 2010 when the detector operated with 59 strings. Using two independent analysis methods, the Moon shadow has been observed to high significance (>6?) in both detector configurations. The observed location of the shadow center is within 0.2 of its expected position when geomagnetic deflection effects are taken into account. This measurement validates the directional reconstruction capabilities of IceCube.

M.?G. Aartsen et al. (IceCube Collaboration)

2014-05-28T23:59:59.000Z

324

WIDESPREAD METHANOL EMISSION FROM THE GALACTIC CENTER: THE ROLE OF COSMIC RAYS  

SciTech Connect (OSTI)

We report the discovery of a widespread population of collisionally excited methanol J = 4{sub -1} to 3{sub 0} E sources at 36.2 GHz from the inner 66' Multiplication-Sign 18' (160 Multiplication-Sign 43 pc) of the Galactic center. This spectral feature was imaged with a spectral resolution of 16.6 km s{sup -1} taken from 41 channels of a Very Large Array continuum survey of the Galactic center region. The revelation of 356 methanol sources, most of which are maser candidates, suggests a large abundance of methanol in the gas phase in the Galactic center region. There is also spatial and kinematic correlation between SiO (2-1) and CH{sub 3}OH emission from four Galactic center clouds: the +50 and +20 km s{sup -1} clouds and G0.13-0.13 and G0.25 + 0.01. The enhanced abundance of methanol is accounted for in terms of induced photodesorption by cosmic rays as they travel through a molecular core, collide, dissociate, ionize, and excite Lyman Werner transitions of H{sub 2}. A time-dependent chemical model in which cosmic rays drive the chemistry of the gas predicts CH{sub 3}OH abundance of 10{sup -8} to 10{sup -7} on a chemical timescale of 5 Multiplication-Sign 10{sup 4} to 5 Multiplication-Sign 10{sup 5} years. The average methanol abundance produced by the release of methanol from grain surfaces is consistent with the available data.

Yusef-Zadeh, F.; Royster, M. [Department of Physics and Astronomy and Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), Northwestern University, Evanston, IL 60208 (United States); Cotton, W. [National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States); Viti, S. [Department of Physics and Astronomy, University College London, Gower St. London, WCIE 6BT (United Kingdom); Wardle, M. [Department of Physics and Astronomy, Macquarie University, Sydney NSW 2109 (Australia)

2013-02-20T23:59:59.000Z

325

An Optimization of the FPGA Based Wavelet Trigger in Radio Detection of Cosmic Rays  

E-Print Network [OSTI]

Experiments that observe coherent radio emission from extensive air showers induced by ultra-high energy cosmic rays are designed for a detailed study of the development of the electromagnetic part of air showers. Radio detectors can operate with 100% up time as e.g. surface detectors based on water-Cherenkov tanks. They are being developed for ground-based experiments (e.g. the Pierre Auger Observatory) as another type of air shower detector in addition to the fluorescence detectors, which operate with only ~10% of duty in dark nights. The radio signals from air showers are caused by the coherent emission due to geomagnetic radiation and charge excess processes. Currently used self-triggers in radio detectors often generate a dense stream of data, which is analyzed afterwards. Huge amounts of registered data requires a significant man-power for the off-line analysis. An improvement of the trigger efficiency becomes a relevant factor. In this work, Morlet wavelets with various scaling factors were used for an analysis of real data from the Auger Engineering Radio Array and for an optimization of the utilization of the resources in an FPGA. The wavelet analysis showed that the power of events is concentrated mostly in a limited range of the frequency spectrum (consistent with a range imposed by the input analog band-pass filter). However, we found several events with suspicious spectral characteristics, where the signal power is spread over the full band-width sampled by a 200 MHz digitizer with significant contribution of very high and very low frequencies. These events may not origin from cosmic ray showers but can be human-made contaminations. The engine of the wavelet analysis can be implemented into the modern powerful FPGA and can remove suspicious events on-line to reduce the trigger rate.

Zbigniew Szadkowski for the Pierre Auger Collaboration

2014-06-04T23:59:59.000Z

326

Cosmic ray neutron background reduction using localized coincidence veto neutron counting  

DOE Patents [OSTI]

This invention relates to both the apparatus and method for increasing the sensitivity of measuring the amount of radioactive material in waste by reducing the interference caused by cosmic ray generated neutrons. The apparatus includes: (a) a plurality of neutron detectors, each of the detectors including means for generating a pulse in response to the detection of a neutron; and (b) means, coupled to each of the neutrons detectors, for counting only some of the pulses from each of the detectors, whether cosmic ray or fission generated. The means for counting includes a means that, after counting one of the pulses, vetos the counting of additional pulses for a prescribed period of time. The prescribed period of time is between 50 and 200 .mu.s. In the preferred embodiment the prescribed period of time is 128 .mu.s. The veto means can be an electronic circuit which includes a leading edge pulse generator which passes a pulse but blocks any subsequent pulse for a period of between 50 and 200 .mu.s. Alternately, the veto means is a software program which includes means for tagging each of the pulses from each of the detectors for both time and position, means for counting one of the pulses from a particular position, and means for rejecting those of the pulses which originate from the particular position and in a time interval on the order of the neutron die-away time in polyethylene or other shield material. The neutron detectors are grouped in pods, preferably at least 10. The apparatus also includes means for vetoing the counting of coincidence pulses from all of the detectors included in each of the pods which are adjacent to the pod which includes the detector which produced the pulse which was counted.

Menlove, Howard O. (Los Alamos, NM); Bourret, Steven C. (Los Alamos, NM); Krick, Merlyn S. (Los Alamos, NM)

2002-01-01T23:59:59.000Z

327

Ultra-High Energy Cosmic Rays from Centaurus A: Jet Interaction with Gaseous Shells  

E-Print Network [OSTI]

Ultra high energy cosmic rays (UHECRs), with energies above ~6 x 10^19 eV, seem to show a weak correlation with the distribution of matter relatively near to us in the universe. It has earlier been proposed that UHECRs could be accelerated in either the nucleus or the outer lobes of the nearby radio galaxy Cen A. We show that UHECR production at a spatially intermediate location about 15 kpc northeast from the nucleus, where the jet emerging from the nucleus is observed to strike a large star-forming shell of gas, is a plausible alternative. A relativistic jet is capable of accelerating lower-energy heavy seed cosmic rays (CRs) to UHECRs on timescales comparable to the time it takes the jet to pierce the large gaseous cloud. In this model many CRs arising from a starburst, with a composition enhanced in heavy elements near the knee region around PeV, are boosted to ultra-high energies by the relativistic shock of a newly oriented jet. This model matches the overall spectrum shown by the Auger data and also makes a prediction for the chemical composition as a function of particle energy. We thus predict an observable anisotropy in the composition at high energy in the sense that lighter nuclei should preferentially be seen toward the general direction of Cen A. Taking into consideration the magnetic field models for the Galactic disk and a Galactic magnetic wind, this scenario may resolve the discrepancy between HiRes and Auger results concerning the chemical composition of UHECRs.

Gopal-Krishna; Peter L. Biermann; Vitor de Souza; Paul J. Wiita

2010-06-25T23:59:59.000Z

328

HIGH-ENERGY EMISSION INDUCED BY ULTRA-HIGH-ENERGY PHOTONS AS A PROBE OF ULTRA-HIGH-ENERGY COSMIC-RAY ACCELERATORS EMBEDDED IN THE COSMIC WEB  

SciTech Connect (OSTI)

The photomeson production in ultra-high-energy cosmic-ray (UHECR) accelerators such as {gamma}-ray bursts and active galaxies may lead to ultra-high-energy (UHE) {gamma}-ray emission. We show that the generation of UHE pairs in magnetized structured regions where the sources are embedded is inevitable, and accompanying {approx}> 0.1 TeV synchrotron emission provides an important probe of UHECR acceleration. It would especially be relevant for powerful transient sources, and synchrotron pair echoes may be detected by future CTA via coordinated search for transients of duration {approx}0.1-1 yr for the structured regions of {approx}Mpc. Detections will be useful for knowing structured extragalactic magnetic fields as well as properties of the sources.

Murase, Kohta [Department of Physics, Center for Cosmology and AstroParticle Physics, Ohio State University, Columbus, OH 43210 (United States)

2012-02-15T23:59:59.000Z

329

HOW MANY ULTRA-HIGH ENERGY COSMIC RAYS COULD WE EXPECT FROM CENTAURUS A?  

SciTech Connect (OSTI)

The Pierre Auger Observatory has associated a few ultra-high energy cosmic rays (UHECRs) with the direction of Centaurus A. This source has been deeply studied in radio, infrared, X-ray, and {gamma}-rays (MeV-TeV) because it is the nearest radio-loud active galactic nucleus. Its spectral energy distribution or spectrum shows two main peaks, the low-energy peak, at an energy of 10{sup -2} eV, and the high-energy peak, at about 150 keV. There is also a faint very high energy (VHE; E {>=} 100 GeV) {gamma}-ray emission fully detected by the High Energy Stereoscopic System experiment. In this work, we describe the entire spectrum: the two main peaks with a synchrotron/synchrotron self-Compton model, and the VHE emission with a hadronic model. We consider p{gamma} and pp interactions. For the p{gamma} interaction, we assume that the target photons are those produced at 150 keV in leptonic processes. On the other hand, for the pp interaction we consider as targets the thermal particle densities in the lobes. Requiring a satisfactory description of the spectra at very high energies with p{gamma} interaction, we obtain an excessive luminosity in UHECRs (even exceeding the Eddington luminosity). However, when considering the pp interaction to describe the {gamma}-spectrum, the number of UHECRs obtained is in agreement with Pierre Auger observations. We also calculate the possible neutrino signal from pp interactions on a Km{sup 3} neutrino telescope using Monte Carlo simulations.

Fraija, N.; Gonzalez, M. M.; Perez, M. [Instituto de Astronomia, Universidad Nacional Autonoma de Mexico, Circuito Exterior, C.U., A. Postal 70-264, 04510 Mexico D.F. (Mexico); Marinelli, A., E-mail: nifraija@astro.unam.mx, E-mail: magda@astro.unam.mx, E-mail: jguillen@astro.unam.mx, E-mail: antonio.marinelli@fisica.unam.mx [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Circuito Exterior, C.U., A. Postal 70-264, 04510 Mexico D.F. (Mexico)

2012-07-01T23:59:59.000Z

330

Passive Imaging of Warhead-Like Configurations Using Cosmic-Ray Muons  

SciTech Connect (OSTI)

Cosmic-Muon-Based Interrogation has untapped potential for national security. This presentation describes muons-based passive interrogation techniques.

Schwellenbach, D.

2012-07-17T23:59:59.000Z

331

Dynamical Feedback of Self-generated Magnetic Fields in Cosmic Rays Modified Shocks  

SciTech Connect (OSTI)

We present a semi-analytical kinetic calculation of the process of non-linear diffusive shock acceleration (NLDSA) which includes magnetic field amplification due to cosmic ray induced streaming instability, the dynamical reaction of the amplified magnetic field and the possible effects of turbulent heating. This kinetic calculation allows us to show that the net effect of the amplified magnetic field is to enhance the maximum momentum of accelerated particles while reducing the concavity of the spectra, with respect to the standard predictions of NLDSA. This is mainly due to the dynamical reaction of the amplified field on the shock, which smoothens the shock precursor. The total compression factors which are obtained for parameters typical of supernova remnants are R{sub tot} {approx} 7-10, in good agreement with the values inferred from observations. The strength of the magnetic field produced through excitation of streaming instability is found in good agreement with the values inferred for several remnants if the thickness of the X-ray rims are interpreted as due to severe synchrotron losses of high energy electrons. We also discuss the relative role of turbulent heating and magnetic dynamical reaction in smoothening the shock precursor.

Caprioli, D.; /Pisa, Scuola Normale Superiore; Blasi, P.; /Arcetri Observ. /Fermilab; Amato, E.; /Arcetri Observ.; Vietri, M.; /Pisa, Scuola Normale Superiore

2008-07-01T23:59:59.000Z

332

?erenkov Counter Flux Measurement of Cosmic-Ray Alphas at 41  

Science Journals Connector (OSTI)

A ?erenkov counter inside a Geiger counter telescope was flown by balloon to a residual atmospheric depth of 16 g/cm2. The purpose of the experiment was to measure the flux of cosmic-ray alpha particles and to investigate the usefulness of a ?erenkov counter for flux measurements on the more heavily charged cosmicray components. A ?erenkov counter was used because of its inherent discrimination against slow secondary particles. The pulse height distribution obtained showed a partially resolved peak at approximately 4 h0, where h0 is the mean pulse height corresponding to a fast proton. This is experimental confirmation of the Z2 dependence for ?erenkov radiation. There were 3024 events which gave pulse heights corresponding to alphas. There is evidence that 451 were due to side showers, 651 were due to nuclear interactions, an additional 478 were due to either side showers or interactions, and 1444 were due to primary alphas. This leads to the value 9916 particles/m2-steradian-second, as the extrapolated flux at the top of the atmosphere. There is also an indication of peaks corresponding to carbon and oxygen. There is evidence that the geometry factor of the telescope was appreciably increased for the heavy components due to the action of delta rays.

Nahmin Horwitz

1955-04-01T23:59:59.000Z

333

Generic Signatures of the Time Profiles of BATSE Cosmic Gamma-Ray Bursts  

Science Journals Connector (OSTI)

A new method is proposed, which allows the study of generic signatures of cosmic gamma-ray burst time histories. We average the 64 ms resolution time profiles of 275 bright bursts detected by BATSE. The profile of each burst is normalized by the maximum number of counts at the peak of the primary pulse, and individual pulses and interpulse valleys are selected from the normalized profiles by identical selection criteria. New generic temporal parameters are introduced, which characterize the duration and equivalent width of each pulse and the duration of each valley. The histograms of the total equivalent pulse width and summed pulse duration are bimodal. Bimodality is also seen in the histogram of the mean duration of individual pulses. Bursts from the short and long peaks of these distributions correspond to the two modes of the Third BATSE Burst Catalog T50 and T90 distributions. Therefore, these new burst parameters demonstrate that the observed bimodal temporal behavior results from properties of the pulsed emission of gamma-ray bursts. The long mode of the T90 histogram includes bursts with from one to ~20 pulses; the logarithmic mean pulse duration is 1.17 0.09 s; for the long events with more than one pulse, the logarithmic mean valley duration is 1.28 0.15 s. Bursts of the short mode of T90 are mainly single-pulse events, and the logarithmic mean pulse duration is much smaller, 0.20 0.01 s. For multipulse bursts of the T90 long mode, marginal correlations were found between the parameters of the pulses and valleys and the number of pulses. The basic signatures of the evolution of pulses and valleys along the time course of bursts are examined. Conclusions are drawn concerning the physics of gamma-ray emission by taking into account these signatures.

Igor; Alexei; Michael S. Briggs; William S. Paciesas; Robert D. Preece; Geoffrey; Charles

1998-01-01T23:59:59.000Z

334

The energy spectrum of cosmic-ray induced neutrons measured on an airplane over a wide range of altitude and latitude  

Science Journals Connector (OSTI)

......radiation dosimetry The energy spectrum of cosmic-ray...Homeland Security, New York, NY 10014, USA 2 Bartol...sensitive extended-energy multisphere neutron...Technical Report EML-595 (New York: US Department of Energy Environmental Measurements......

P. Goldhagen; J. M. Clem; J. W. Wilson

2004-08-01T23:59:59.000Z

335

Observations of Large Scale Sidereal Anisotropy in 1 and 11 TeV cosmic rays from the MINOS experiment  

SciTech Connect (OSTI)

The MINOS Near and Far Detectors are two large, functionally-identical, steel-scintillating sampling calorimeters located at depths of 220 mwe and 2100 mwe respectively. The detectors observe the muon component of hadronic showers produced from cosmic ray interactions with nuclei in the earth's atmosphere. From the arrival direction of these muons, the anisotropy in arrival direction of the cosmic ray primaries can be determined. The MINOS Near and Far Detector have observed anisotropy on the order of 0.1% at 1 and 11 TeV respectively. The amplitude and phase of the first harmonic at 1 TeV are 8.2 {+-} 1.7(stat.) x 10{sup -4} and (8.9 {+-} 12.1(stat.)){sup o}, and at 11 TeV are 3.8 {+-} 0.5(stat.) x 10{sup -4} and (27.2 {+-} 7.2(stat.)){sup o}.

de Jong, J.K.

2012-01-01T23:59:59.000Z

336

Cosmic X-ray Surveys of Distant Active Galaxies: The Demographics, Physics, and Ecology of Growing Supermassive Black Holes  

E-Print Network [OSTI]

We review results from cosmic X-ray surveys of active galactic nuclei (AGNs) over the past ~ 15 yr that have dramatically improved our understanding of growing supermassive black holes (SMBHs) in the distant universe. First, we discuss the utility of such surveys for AGN investigations and the capabilities of the missions making these surveys, emphasizing Chandra, XMM-Newton, and NuSTAR. Second, we briefly describe the main cosmic X-ray surveys, the essential roles of complementary multiwavelength data, and how AGNs are selected from these surveys. We then review key results from these surveys on the AGN population and its evolution ("demographics"), the physical processes operating in AGNs ("physics"), and the interactions between AGNs and their environments ("ecology"). We conclude by describing some significant unresolved questions and prospects for advancing the field.

Brandt, W N

2015-01-01T23:59:59.000Z

337

THEORETICAL EXPLANATION OF THE COSMIC-RAY PERPENDICULAR DIFFUSION COEFFICIENT IN THE NEARBY STARBURST GALAXY NGC 253  

SciTech Connect (OSTI)

Diffusion coefficients are usually used to describe the propagation of cosmic rays through the universe. Whereas such transport parameters can be obtained from experiments in the solar system, it is difficult to determine diffusion coefficients in the Milky Way or in external galaxies. Recently, a value for the perpendicular diffusion coefficient in the nearby starburst galaxy NGC 253 has been proposed. In the present paper, we reproduce this value theoretically by using an advanced analytical theory for perpendicular diffusion.

Buffie, K.; Shalchi, A. [Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2 (Canada)] [Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2 (Canada); Heesen, V., E-mail: shalchi@physics.umanitoba.ca, E-mail: v.heesen@soton.ac.uk [School for Physics and Astronomy, University of Southampton, Southampton SO17 1BJ (United Kingdom)

2013-02-10T23:59:59.000Z

338

Relative Composition and Energy Spectra of Light Nuclei in Cosmic Rays. Results from AMS-01  

E-Print Network [OSTI]

Measurement of the chemical and isotopic composition of cosmic rays is essential for the precise understanding of their propagation in the galaxy. While the model parameters are mainly determined using the B/C ratio, the study of extended sets of ratios can provide stronger constraints on the propagation models. In this paper the relative abundances of the light nuclei lithium, beryllium, boron and carbon are presented. The secondary to primary ratios Li/C, Be/C and B/C have been measured in the kinetic energy range 0.35-45 GeV/nucleon. The isotopic ratio 7Li/6Li is also determined in the magnetic rigidity interval 2.5-6.3 GV. The secondary to secondary ratios Li/Be, Li/B and Be/B are also reported. These measurements are based on the data collected by the Alpha Magnetic Spectrometer AMS-01 during the STS-91 space shuttle flight in 1998 June. Our experimental results are in substantial agreement with other measurements, where they exist. We describe our light-nuclei data with a diffusive-reacceleration model....

Aguilar, M; Allaby, J; Alpat, B; Ambrosi, G; Anderhub, H; Ao, L; Arefiev, A; Arruda, L; Azzarello, P; Basile, M; Barao, F; Barreira, G; Vartoloni, A; Battiston, R; Becker, R; Becker, U; Bellagamba, L; Bene, P; Berdugo, J; Berges, P; Bertucci, B; Biland, A; Bindi, V; Boella, G; Boschini, M; Bourquin, M; Bruni, G; Buenerd, M; Burger, J D; Burger, W J; Cai, X D; Cannarsa, P; Capell, M; Casadei, D; Casaus, J; Castellini, G; Cernuda, I; Chang, Y H; Chen, H F; Chen, H S; Chen, Z G; Chernoplekov, N A; Chiueh, T H; Choi, Y Y; Cindolo, F; Commichau, V; Contin, A; Cortina-Gil, E; Crespo, D; Cristinziani, M; Dai, T S; Dela Guia, C; Delgado, C; Di Falco, S; Djambazov, L; D'Antoine, I; Dong, Z R; Duranti, M; Engelberg, J; Eppling, F J; Eronen, T; Extermann, P; Favier, J; Fiandrini, E; Fisher, P H; Flugge, G; Fouque, N; Galaktionov, Y; Gervasi, M; Giovacchini, F; Giusti, P; Grandi, D; Grimm, O; Gu, W Q; Haino, S; Hangarter, K; Hasan, A; Hermel, V; Hofer, H; Hungerford, W; Ionica, M; Jongmanns, M; Karlamaa, K; Karpinski, W; Kenney, G; Kim, D H; Kim, G N; Kim, K S; Kirn, T; Klimentov, A; Kossakowski, R; Kounine, A; Koutsenko, V; Kraeber, M; Laborie, G; Laitinen, T; Lamanna, G; Laurenti, G; Lebedev, A; Lechanoine-Leluc, C; Lee, M W; Lee, S C; Levi, G; Lin, C H; Liu, H T; Lu, G; Lubelsmeyer, K; Luckey, D; Lustermann, W; Mana, C; Margotti, A; Mayet, F; McNeil, R R; Menichelli, M; Mihul, A; Mujunen, A; Oliva, A; Palmonari, F; Park, H B; Park, W H; Pauluzzi, M; Pauss, F; Pereira, R; Perrin, E; Pevsner, A; Pilo, F; Pimenta, M; Plyaskin, V; Pojidaev, V; Pohl, M; Produit, N; Quadrani, L; Rancoita, P G; Rapin, D; Ren, D; Ren, Z; Ribordy, M; Richeux, J P; Riihonen, E; Ritakari, J; Ro, S; Roeser, U; Sagdeev, R; Santos, D; Sartorelli, G; Sbarra, C; Schael, S; Schultz von Dratzig, A; Schwering, G; Seo, E S; Shin, J W; Shoumilov, E; Shoutko, V; Siedenburg, T; Siedling, R; Son, D; Song, T; Spada, F R; Spinella, F; Steuer, M; Sun, G S; Suter, H; Tang, X W; Ting, Samuel C C; Ting, S M; Tomassetti, N; Tornikoski, M; Torsti, J; Trumper, J; Ulbricht, J; Urpo, S; Valtonen, E; Vandenhirtz, J; Velikhov, E; Verlaat, B; Vetlitsky, I; Vezzu, F; Vialle, J P; Viertel, G; Vite, D; Von Gunten, H; Waldmeier Wicki, S; Wallraff, W; Wang, J Z; Wiik, K; Williams, C; Wu, S X; Xia, P C; Xu, S; Xu, Z Z; Yan, J L; Yan, L G; Yang, C G; Yang, J; Yang, M; Ye, S W; Zhang, H Y; Zhang, Z P; Zhao, D X; Zhou, F; Zhou, Y; Zhu, G Y; Zhu, W Z; Zhuang, H L; Zichichi, A; Zimmermann, B; Zuccon, P

2010-01-01T23:59:59.000Z

339

Relative Composition and Energy Spectra of Light Nuclei in Cosmic Rays. Results from AMS-01  

E-Print Network [OSTI]

Measurement of the chemical and isotopic composition of cosmic rays is essential for the precise understanding of their propagation in the galaxy. While the model parameters are mainly determined using the B/C ratio, the study of extended sets of ratios can provide stronger constraints on the propagation models. In this paper the relative abundances of the light nuclei lithium, beryllium, boron and carbon are presented. The secondary to primary ratios Li/C, Be/C and B/C have been measured in the kinetic energy range 0.35-45 GeV/nucleon. The isotopic ratio 7Li/6Li is also determined in the magnetic rigidity interval 2.5-6.3 GV. The secondary to secondary ratios Li/Be, Li/B and Be/B are also reported. These measurements are based on the data collected by the Alpha Magnetic Spectrometer AMS-01 during the STS-91 space shuttle flight in 1998 June. Our experimental results are in substantial agreement with other measurements, where they exist. We describe our light-nuclei data with a diffusive-reacceleration model. A 10-15% overproduction of Be is found in the model predictions and can be attributed to uncertainties in the production cross-section data.

The AMS-01 Collaboration

2010-08-30T23:59:59.000Z

340

Radio detection of high-energy cosmic rays at the Pierre Auger Observatory  

E-Print Network [OSTI]

The southern Auger Observatory provides an excellent test bed to study the radio detection of extensive air showers as an alternative, cost-effective, and accurate tool for cosmic-ray physics. The data from the radio setup can be correlated with those from the well-calibrated baseline detectors of the Pierre Auger Observatory. Furthermore, human-induced radio noise levels at the southern Auger site are relatively low. We have started an R&D program to test various radio-detection concepts. Our studies will reveal Radio Frequency Interferences (RFI) caused by natural effects such as day-night variations, thunderstorms, and by human-made disturbances. These RFI studies are conducted to optimise detection parameters such as antenna design, frequency interval, antenna spacing and signal processing. The data from our initial setups, which presently consist of typically 3 - 4 antennas, will be used to characterise the shower from radio signals and to optimise the initial concepts. Furthermore, the operation of a large detection array requires autonomous detector stations. The current design is aiming at stations with antennas for two polarisations, solar power, wireless communication, and local trigger logic. The results of this initial phase will provide an important stepping stone for the design of a few tens kilometers square engineering array

A. M. van den Berg; for the Pierre Auger Collaboration

2007-08-13T23:59:59.000Z

Note: This page contains sample records for the topic "int cosmic ray" from the National Library of EnergyBeta (NLEBeta).
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they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

The isotropy problem of Sub-ankle Ultra-high energy cosmic rays  

E-Print Network [OSTI]

We study the time dependent propagation of sub-ankle ultra-high energy cosmic rays (UHECRs) originating from point-like Galactic sources. We show that drift in the Galactic magnetic field (GMF) may play an important role in the propagation of UHECRs and their measured anisotropy, particularly when the transport is anisotropic. To fully account for the discreteness of UHECR sources in space and time, a Monte Carlo method is used to randomly place sources in the Galaxy. The low anisotropy measured by Auger is not generally characteristic of the theoretical models, given that the sources are distributed in proportion to the star formation rate, but it can possibly be understood as a) intermittency effects due to the discrete nature of the sources or, with extreme parameters, b) a cancellation of drift current along a current sheet with the outward radial diffusive flux. We conclude that it is possible to interpret the Galactic sub-ankle CR flux as being due entirely to intermittent discrete Galactic sources dist...

Kumar, Rahul

2013-01-01T23:59:59.000Z

342

Comparison of the ultrahigh energy cosmic ray flux observed by AGASA, HiRes, and Auger  

Science Journals Connector (OSTI)

The current measurements of the cosmic ray energy spectrum at ultra-high energies (E>1019??eV) are characterized by large systematic errors and poor statistics. In addition, the experimental results of the two experiments with the largest published data sets, AGASA and HiRes, appear to be inconsistent with each other, with AGASA seeing an unabated continuation of the energy spectrum even at energies beyond the Greisen-Zatsepin-Kuzmin cutoff energy at 1019.6??eV. Given the importance of the related astrophysical questions regarding the unknown origin of these highly energetic particles, it is crucial that the extent to which these measurements disagree be well understood. Here we evaluate the consistency of the two measurements for the first time with a model-independent method that accounts for the large statistical and systematic errors of current measurements. We further compare the AGASA and HiRes spectra with the recently presented Auger spectrum. The method directly compares two measurements, bypassing the introduction of theoretical models for the shape of the energy spectrum. The inconsistency between the observations is expressed in terms of a Bayes factor, a standard statistic defined as the ratio of a separate parent source hypothesis to a single parent source hypothesis. Application to the data shows that the two-parent hypothesis is disfavored. We expand the method to allow comparisons between an experimental flux and that predicted by any model.

B. M. Connolly; S. Y. BenZvi; C. B. Finley; A. C. ONeill; S. Westerhoff

2006-08-07T23:59:59.000Z

343

Relative Composition and Energy Spectra of Light Nuclei in Cosmic Rays: Results from AMS-01  

Science Journals Connector (OSTI)

Measurement of the chemical and isotopic composition of cosmic rays is essential for the precise understanding of their propagation in the galaxy. While the model parameters are mainly determined using the B/C ratio, the study of extended sets of ratios can provide stronger constraints on the propagation models. In this paper, the relative abundances of light-nuclei lithium, beryllium, boron, and carbon are presented. The secondary-to-primary ratios Li/C, Be/C, and B/C have been measured in the kinetic energy range 0.35-45GeVnucleon1. The isotopic ratio 7Li/6Li is also determined in the magnetic rigidity interval 2.5-6.3GV. The secondary-to-secondary ratios Li/Be, Li/B, and Be/B are also reported. These measurements are based on the data collected by the Alpha Magnetic Spectrometer AMS-01 during the STS-91 space shuttle flight in 1998 June. Our experimental results are in substantial agreement with other measurements, where they exist. We describe our light-nuclei data with a diffusive-reacceleration model. A 10%-15% overproduction of Be is found in the model predictions and can be attributed to uncertainties in the production cross-section data.

M. Aguilar; J. Alcaraz; J. Allaby; B. Alpat; G. Ambrosi; H. Anderhub; L. Ao; A. Arefiev; L. Arruda; P. Azzarello; M. Basile; F. Barao; G. Barreira; A. Bartoloni; R. Battiston; R. Becker; U. Becker; L. Bellagamba; P. Bn; J. Berdugo; P. Berges; B. Bertucci; A. Biland; V. Bindi; G. Boella; M. Boschini; M. Bourquin; G. Bruni; M. Bunerd; J. D. Burger; W. J. Burger; X. D. Cai; P. Cannarsa; M. Capell; D. Casadei; J. Casaus; G. Castellini; I. Cernuda; Y. H. Chang; H. F. Chen; H. S. Chen; Z. G. Chen; N. A. Chernoplekov; T. H. Chiueh; Y. Y. Choi; F. Cindolo; V. Commichau; A. Contin; E. Cortina-Gil; D. Crespo; M. Cristinziani; T. S. Dai; C. dela Guia; C. Delgado; S. Di Falco; L. Djambazov; I. D'Antone; Z. R. Dong; M. Duranti; J. Engelberg; F. J. Eppling; T. Eronen; P. Extermann; J. Favier; E. Fiandrini; P. H. Fisher; G. Flgge; N. Fouque; Y. Galaktionov; M. Gervasi; F. Giovacchini; P. Giusti; D. Grandi; O. Grimm; W. Q. Gu; S. Haino; K. Hangarter; A. Hasan; V. Hermel; H. Hofer; W. Hungerford; M. Ionica; M. Jongmanns; K. Karlamaa; W. Karpinski; G. Kenney; D. H. Kim; G. N. Kim; K. S. Kim; T. Kirn; A. Klimentov; R. Kossakowski; A. Kounine; V. Koutsenko; M. Kraeber; G. Laborie; T. Laitinen; G. Lamanna; G. Laurenti; A. Lebedev; C. Lechanoine-Leluc; M. W. Lee; S. C. Lee; G. Levi; C. H. Lin; H. T. Liu; G. Lu; Y. S. Lu; K. Lbelsmeyer; D. Luckey; W. Lustermann; C. Maa; A. Margotti; F. Mayet; R. R. McNeil; M. Menichelli; A. Mihul; A. Mujunen; A. Oliva; F. Palmonari; H. B. Park; W. H. Park; M. Pauluzzi; F. Pauss; R. Pereira; E. Perrin; A. Pevsner; F. Pilo; M. Pimenta; V. Plyaskin; V. Pojidaev; M. Pohl; N. Produit; L. Quadrani; P. G. Rancoita; D. Rapin; D. Ren; Z. Ren; M. Ribordy; J. P. Richeux; E. Riihonen; J. Ritakari; S. Ro; U. Roeser; R. Sagdeev; D. Santos; G. Sartorelli; C. Sbarra; S. Schael; A. Schultz von Dratzig; G. Schwering; E. S. Seo; J. W. Shin; E. Shoumilov; V. Shoutko; T. Siedenburg; R. Siedling; D. Son; T. Song; F. R. Spada; F. Spinella; M. Steuer; G. S. Sun; H. Suter; X. W. Tang; Samuel C. C. Ting; S. M. Ting; N. Tomassetti; M. Tornikoski; J. Torsti; J. Trmper; J. Ulbricht; S. Urpo; E. Valtonen; J. Vandenhirtz; E. Velikhov; B. Verlaat; I. Vetlitsky; F. Vezzu; J. P. Vialle; G. Viertel; D. Vit; H. Von Gunten; S. Waldmeier Wicki; W. Wallraff; J. Z. Wang; K. Wiik; C. Williams; S. X. Wu; P. C. Xia; S. Xu; Z. Z. Xu; J. L. Yan; L. G. Yan; C. G. Yang; J. Yang; M. Yang; S. W. Ye; H. Y. Zhang; Z. P. Zhang; D. X. Zhao; F. Zhou; Y. Zhou; G. Y. Zhu; W. Z. Zhu; H. L. Zhuang; A. Zichichi; B. Zimmermann; P. Zuccon

2010-01-01T23:59:59.000Z

344

THE MODULATION OF GALACTIC COSMIC-RAY ELECTRONS IN THE HELIOSHEATH  

SciTech Connect (OSTI)

Voyager 1 has observed strong increases in the intensities of 2-160 MeV electrons since crossing the termination shock of the heliosphere in 2004 December. Before this time these intensities were submerged below the detector background, except for occasional transient events. These increases are large compared to the concurrent increases of positive ions such as H, He, and O. A significant part is probably due to temporal effects as the heliosphere was recovering to solar minimum conditions from 2005 to early 2010. The intensity observed by Voyager 2 since its crossing of the shock in 2007 September is 5-10 times lower than that observed by Voyager 1, which is so low that the electron intensity may still be below the background produced by high-energy protons in the detector. This points to a large north-south asymmetry in the properties of the heliosheath. It is shown that the observations suggest that these electrons are not freshly accelerated on the termination shock, but rather that they are of galactic origin-while they may be re-accelerated by that shock. In this paper, these intensities are modeled with numerical solutions of the cosmic-ray transport equation. It is shown that because they are relativistic, the electrons are much more sensitive to the form of the diffusion coefficient at low rigidities than ions, and that this can explain the asymmetry.

Caballero-Lopez, R. A. [Instituto de Geofisica, UNAM, 04510 Mexico, D. F. (Mexico); Moraal, H. [Unit for Space Physics, School of Physical and Chemical Sciences, North-West University, Potchefstroom 2520 (South Africa); McDonald, F. B., E-mail: rogelioc@geofisica.unam.m [Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742 (United States)

2010-12-10T23:59:59.000Z

345

Escape model for Galactic cosmic rays and an early extragalactic transition  

E-Print Network [OSTI]

We show that the cosmic ray (CR) knee can be entirely explained by energy-dependent CR leakage from the Milky Way, with an excellent fit to all existing data. We test this hypothesis calculating the trajectories of individual CRs in the Galactic magnetic field. We find that the CR escape time $\\tau_{\\rm esc}(E)$ exhibits a knee-like structure around $E/Z={\\rm few}\\times 10^{15}$ eV for small coherence lengths and strengths of the turbulent magnetic field. The resulting intensities for different groups of nuclei are consistent with the ones determined by KASCADE and KASCADE-Grande, using simple power-laws as injection spectra. The transition from Galactic to extragalactic CRs is terminated at $\\approx 2\\times 10^{18}$ eV, while extragalactic CRs contribute sizeable to the subdominant proton flux already for $\\gtrsim 2\\times 10^{16}$ eV. The natural source of extragalactic CRs in the intermediate energy region up to the ankle are in this model normal and starburst galaxies. The escape model provides a good fit ...

Giacinti, G; Semikoz, D V

2015-01-01T23:59:59.000Z

346

Measurement of the cosmic ray and neutrino-induced muon flux at the Sudbury neutrino observatory  

Science Journals Connector (OSTI)

Results are reported on the measurement of the atmospheric neutrino-induced muon flux at a depth of 2 kilometers below the Earths surface from 1229 days of operation of the Sudbury Neutrino Observatory (SNO). By measuring the flux of through-going muons as a function of zenith angle, the SNO experiment can distinguish between the oscillated and unoscillated portion of the neutrino flux. A total of 514 muonlike events are measured between -1?cos??zenith?0.4 in a total exposure of 2.301014??cm2?s. The measured flux normalization is 1.220.09 times the Bartol three-dimensional flux prediction. This is the first measurement of the neutrino-induced flux where neutrino oscillations are minimized. The zenith distribution is consistent with previously measured atmospheric neutrino oscillation parameters. The cosmic ray muon flux at SNO with zenith angle cos??zenith>0.4 is measured to be (3.310.01(stat)0.09(sys))10-10???/s/cm2.

B. Aharmim et al. (SNO Collaboration)

2009-07-10T23:59:59.000Z

347

E-Print Network 3.0 - antimatter cosmic rays Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

the cosmic questions... % Anti-Matter 0% stars baryon neutrinos dark matter dark energy "The ... Source: Murayama, Hitoshi - Department of Physics, University of California...

348

Earth X-ray albedo for cosmic X-ray background radiation in the 1--1000 keV band  

E-Print Network [OSTI]

We present calculations of the reflection of the cosmic X-ray background (CXB) by the Earth's atmosphere in the 1--1000 keV energy range. The calculations include Compton scattering and X-ray fluorescent emission and are based on a realistic chemical composition of the atmosphere. Such calculations are relevant for CXB studies using the Earth as an obscuring screen (as was recently done by INTEGRAL). The Earth's reflectivity is further compared with that of the Sun and the Moon -- the two other objects in the Solar system subtending a large solid angle on the sky, as needed for CXB studies.

E. Churazov; S. Sazonov; R. Sunyaev; M. Revnivtsev

2008-02-11T23:59:59.000Z

349

The IceCube Collaboration:contributions to the 30 th International Cosmic Ray Conference (ICRC 2007),  

SciTech Connect (OSTI)

This paper bundles 40 contributions by the IceCube collaboration that were submitted to the 30th International Cosmic Ray Conference ICRC 2007. The articles cover studies on cosmic rays and atmospheric neutrinos, searches for non-localized, extraterrestrial {nu}{sub e}, {nu}{sub {mu}} and {nu}{sub {tau}} signals, scans for steady and intermittent neutrino point sources, searches for dark matter candidates, magnetic monopoles and other exotic particles, improvements in analysis techniques, as well as future detector extensions. The IceCube observatory will be finalized in 2011 to form a cubic-kilometer ice-Cherenkov detector at the location of the geographic South Pole. At the present state of construction, IceCube consists of 52 paired IceTop surface tanks and 22 IceCube strings with a total of 1426 Digital Optical Modules deployed at depths up to 2350 m. The observatory also integrates the 19 string AMANDA subdetector, that was completed in 2000 and extends IceCube's reach to lower energies. Before the deployment of IceTop, cosmic air showers were registered with the 30 station SPASE-2 surface array. IceCube's low noise Digital Optical Modules are very reliable, show a uniform response and record waveforms of arriving photons that are resolvable with nanosecond precision over a large dynamic range. Data acquisition, reconstruction and simulation software are running in production mode and the analyses, profiting from the improved data quality and increased overall sensitivity, are well under way.

IceCube Collaboration; Ackermann, M.

2007-11-02T23:59:59.000Z

350

Magnetars in the Metagalaxy: An Origin for Ultra High Energy Cosmic Rays in the Nearby Universe  

E-Print Network [OSTI]

I show that the relativistic winds of newly born magnetars with khz initial spin rates, occurring in all normal galaxies, can accelerate ultrarelativistic light ions with an E^{-1} injection spectrum, steepening to E^{-2} at higher energies, with an upper cutoff above 10^{21} eV. Interactions with the CMB yield a spectrum in good accord with the observed spectrum of Ultra-High Energy Cosmic Rays (UHECR), if ~ 5-10% of the magnetars are born with voltages sufficiently high to accelerate the UHECR. The form the spectrum spectrum takes depends on the gravitational wave losses during the magnetars' early spindown - pure electromagnetic spindown yields a flattening of the E^3 J(E) spectrum below 10^{20} eV, while a moderate GZK ``cutoff'' appears if gravitational wave losses are strong enough. I outline the physics such that the high energy particles escape with small energy losses from a magnetar's natal supernova, including Rayleigh-Taylor ``shredding'' of the supernova envelope, expansion of a relativistic blast wave into the interstellar medium, acceleration of the UHE ions through surf-riding in the electromgnetic fields of the wind, and escape of the UHE ions in the rotational equator with negligible radiation loss. The abundance of interstellar supershells and unusually large supernova remnants suggests that most of the initial spindown energy is radiated in khz gravitational waves for several hours after each supernova, with effective strains from sources at typical distances ~ 3 x 10^{-21}. Such bursts of gravitational radiation should correlate with bursts of ultra-high energy particles. The Auger experiment should see such bursts every few years.

Jonathan Arons

2002-08-23T23:59:59.000Z

351

Magnetic lensing of extremely high energy cosmic rays in a galactic wind  

E-Print Network [OSTI]

We show that in the model of Galactic magnetic wind recently proposed to explain the extremely high energy (EHE) cosmic rays so far observed as originating from a single source (M87 in the Virgo cluster), the magnetic field strongly magnifies the fluxes and produces multiple images of the source. The apparent position on Earth of the principal image moves, for decreasing energies, towards the galactic south. It is typically amplified by an order of magnitude at $E/Z\\sim 2\\times 10^{20}$ eV, but becomes strongly demagnified below $10^{20}$ eV. At energies below $E/Z\\sim 1.3\\times 10^{20}$ eV, all events in the northern galactic hemisphere are due to secondary images, which have huge amplifications ($>10^2$). This model would imply strong asymmetries between the north and south galactic hemispheres, such as a (latitude dependent) upper cut-off value below $2\\times 10^{20}$ eV for CR protons arriving to the south and lower fluxes in the south than in the north above $10^{20}$ eV. The large resulting magnifications reduce the power requirements on the source, but the model needs a significant tunning between the direction to the source and the symmetry axis of the wind. If more modest magnetic field strengths were assumed, a scenario in which the observed EHE events are heavier nuclei whose flux is strongly lensed becomes also plausible and would predict that a transition from a light composition to a heavier one could take place at the highest energies.

Diego Harari; Silvia Mollerach; Esteban Roulet

2000-05-24T23:59:59.000Z

352

Cosmic-ray interactions in charged-couple devices in the DMTPC 4-shooter detector  

E-Print Network [OSTI]

The Dark Matter Time Projection Chamber (DMTPC) is a low pressure (CF 4) detector that measures the two-dimensional vector direction of nuclear recoils, and it aims to directly detect dark matter. This paper explores cosmic ...

Choi, HyoJeong

2013-01-01T23:59:59.000Z

353

DIFFUSE EMISSION MEASUREMENT WITH THE SPECTROMETER ON INTEGRAL AS AN INDIRECT PROBE OF COSMIC-RAY ELECTRONS AND POSITRONS  

SciTech Connect (OSTI)

Significant advances have been made in the understanding of the diffuse Galactic hard X-ray continuum emission using data from the INTEGRAL observatory. The diffuse hard power-law component seen with the SPectrometer on INTEGRAL (SPI) has been identified with inverse-Compton emission from relativistic (GeV) electrons on the cosmic microwave background and Galactic interstellar radiation field. In the present analysis, SPI data from 2003 to 2009, with a total exposure time of {approx}10{sup 8} s, are used to derive the Galactic ridge hard X-ray spatial distribution and spectrum between 20 keV and 2.4 MeV. Both are consistent with predictions from the GALPROP code. The good agreement between measured and predicted emission from keV to GeV energies suggests that the correct production mechanisms have been identified. We discuss the potential of the SPI data to provide an indirect probe of the interstellar cosmic-ray electron distribution, in particular for energies below a few GeV.

Bouchet, Laurent; Jourdain, Elisabeth; Roques, Jean-Pierre [Universite de Toulouse, UPS-OMP, IRAP, Toulouse (France); Strong, Andrew W. [Max-Planck-Institut fuer extraterrestrische Physik, Postfach 1603, 85740 Garching (Germany); Porter, Troy A.; Moskalenko, Igor V., E-mail: bouchet@cesr.fr [Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305 (United States)

2011-09-20T23:59:59.000Z

354

Origin of Cosmic Radiation  

E-Print Network [OSTI]

I give a brief overview of cosmic ray physics, highlighting some key questions and how they will be addressed by new experiments.

Thomas K. Gaisser

2000-11-28T23:59:59.000Z

355

High-Energy Cosmic-Ray Muons Under Thick Layers of Matter I. a Method to Solve the Transport Equation  

E-Print Network [OSTI]

An effective analytical method for calculating energy spectra of cosmic-ray muons at large depths of homogeneous media is developed. The method allows to include an arbitrary (decreasing) muon spectrum at the medium boundary and the energy dependence of both discrete (radiative and photonuclear) and continuous (ionization) muon energy losses, with resonable requirements for the high-energy behavior of the initial spectrum and differential cross sections of the muon-matter interactions. (To be published in the Proceedings of the Second NESTOR International Workshop, 19 -- 21 October 1992, Pylos, Greece.)

V. A. Naumov; S. I. Sinegovsky; E. V. Bugaev

1993-01-22T23:59:59.000Z

356

Energy spectrum of cosmic ray muons in ?100TeV energy region reconstructed from the BUST data  

Science Journals Connector (OSTI)

Inclusive differential and integral energy spectra of cosmic ray muons in the energy range from several TeV to ?1PeV obtained by means of the analysis of multiple interactions of muons (pair meter technique) in the Baksan underground scintillation telescope (BUST) are presented. The results are compared with preceding BUST data on muon energy spectrum based on electromagnetic cascade shower measurements and depth-intensity curve analysis, with calculations for different muon spectrum models, and also with data of other experiments.

A.G. Bogdanov; R.P. Kokoulin; Yu.F. Novoseltsev; R.V. Novoseltseva; V.B. Petkov; A.A. Petrukhin

2012-01-01T23:59:59.000Z

357

Observation of the Ankle and Evidence for a High-Energy Break in the Cosmic Ray Spectrum  

E-Print Network [OSTI]

We have measured the cosmic ray spectrum at energies above $10^{17}$ eV using the two air fluorescence detectors of the High Resolution Fly's Eye experiment operating in monocular mode. We describe the detector, PMT and atmospheric calibrations, and the analysis techniques for the two detectors. We fit the spectrum to models describing galactic and extragalactic sources. Our measured spectrum gives an observation of a feature known as the ``ankle'' near $3\\times 10^{18}$ eV, and strong evidence for a suppression near $6\\times 10^{19}$ eV.

The High Resolution Fly's Eye Collaboration

2005-06-07T23:59:59.000Z

358

Regions of an excessive flux of cosmic rays according to data of the FIAN and MSU arrays  

E-Print Network [OSTI]

Results of a blind search for localized regions of an excessive flux of cosmic rays in the energy range from 50 TeV to 20 PeV with the data of the FIAN KLARA-Chronotron experiment, the EAS MSU array and the Prototype of the EAS-1000 array are presented. A number of regions with a significant excess of the registered flux over an expected isotropic background are found. Some of the regions are present in at least two of the data sets considered.

Gudkova, E N; Kalmykov, N N; Kulikov, G V; Nesterova, N M; Pavlyuchenko, V P

2015-01-01T23:59:59.000Z

359

Bounds on the density of sources of ultra-high energy cosmic rays from the Pierre Auger Observatory  

SciTech Connect (OSTI)

We derive lower bounds on the density of sources of ultra-high energy cosmic rays from the lack of significant clustering in the arrival directions of the highest energy events detected at the Pierre Auger Observatory. The density of uniformly distributed sources of equal intrinsic intensity was found to be larger than ? (0.06?5) 10{sup ?4} Mpc{sup ?3} at 95% CL, depending on the magnitude of the magnetic deflections. Similar bounds, in the range (0.2?7) 10{sup ?4} Mpc{sup ?3}, were obtained for sources following the local matter distribution.

Collaboration: Pierre Auger Collaboration

2013-05-01T23:59:59.000Z

360

Updated cosmic-ray and radio constraints on light dark matter: Implications for the GeV gamma-ray excess at the Galactic center  

E-Print Network [OSTI]

The apparent gamma-ray excess in the Galactic center region and inner Galaxy has attracted considerable interest, notably because both its spectrum and radial distribution are consistent with an interpretation in terms of annihilating dark matter particles with a mass of about 10-40 GeV. We confront such an interpretation with an updated compilation of various indirect dark matter detection bounds, which we adapt to the specific form required by the observed signal. We find that cosmic-ray positron data strongly rule out dark matter annihilating to light leptons, or 'democratically' to all leptons, as an explanation of the signal. Cosmic-ray antiprotons, for which we present independent and significantly improved limits with respect to previous estimates, are already in considerable tension with DM annihilation to any combination of quark final states; the first set of AMS-02 data will thus be able to rule out or confirm the DM hypothesis with high confidence. For reasonable assumptions about the magnetic field in the Galactic center region, radio observations independently put very severe constraints on a DM interpretation of the excess, in particular for all leptonic annihilation channels.

Torsten Bringmann; Martin Vollmann; Christoph Weniger

2014-06-23T23:59:59.000Z

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361

LARGE-SCALE DISTRIBUTION OF ARRIVAL DIRECTIONS OF COSMIC RAYS DETECTED ABOVE 10{sup 18} eV AT THE PIERRE AUGER OBSERVATORY  

SciTech Connect (OSTI)

A thorough search for large-scale anisotropies in the distribution of arrival directions of cosmic rays detected above 10{sup 18} eV at the Pierre Auger Observatory is presented. This search is performed as a function of both declination and right ascension in several energy ranges above 10{sup 18} eV, and reported in terms of dipolar and quadrupolar coefficients. Within the systematic uncertainties, no significant deviation from isotropy is revealed. Assuming that any cosmic-ray anisotropy is dominated by dipole and quadrupole moments in this energy range, upper limits on their amplitudes are derived. These upper limits allow us to test the origin of cosmic rays above 10{sup 18} eV from stationary Galactic sources densely distributed in the Galactic disk and predominantly emitting light particles in all directions.

Abreu, P.; Andringa, S. [LIP and Instituto Superior Tecnico, Technical University of Lisbon (Portugal); Aglietta, M. [Istituto di Fisica dello Spazio Interplanetario (INAF), Universita di Torino and Sezione INFN, Torino (Italy); Ahlers, M. [University of Wisconsin, Madison, WI (United States); Ahn, E. J. [Fermilab, Batavia, IL (United States); Albuquerque, I. F. M. [Instituto de Fisica, Universidade de Sao Paulo, Sao Paulo, SP (Brazil); Allard, D. [Laboratoire AstroParticule et Cosmologie (APC), Universite Paris 7, CNRS-IN2P3, Paris (France); Allekotte, I. [Centro Atomico Bariloche and Instituto Balseiro (CNEA-UNCuyo-CONICET), San Carlos de Bariloche (Argentina); Allen, J. [New York University, New York, NY (United States); Allison, P. [Ohio State University, Columbus, OH (United States); Almela, A. [Facultad Regional Buenos Aires, Universidad Tecnologica Nacional, Buenos Aires (Argentina); Alvarez Castillo, J. [Universidad Nacional Autonoma de Mexico, Mexico, D. F. (Mexico); Alvarez-Muniz, J. [Universidad de Santiago de Compostela (Spain); Alves Batista, R. [IFGW, Universidade Estadual de Campinas, Campinas, SP (Brazil); Ambrosio, M.; Aramo, C. [Universita di Napoli 'Federico II' and Sezione INFN, Napoli (Italy); Aminaei, A. [IMAPP, Radboud University Nijmegen (Netherlands); Anchordoqui, L. [University of Wisconsin, Milwaukee, WI (United States); Antici'c, T. [Rudjer Boskovi'c Institute, 10000 Zagreb (Croatia); Arganda, E. [IFLP, Universidad Nacional de La Plata and CONICET, La Plata (Argentina); Collaboration: Pierre Auger Collaboration; and others

2012-12-15T23:59:59.000Z

362

CONSTRAINTS ON THE ORIGIN OF COSMIC RAYS ABOVE 10{sup 18} eV FROM LARGE-SCALE ANISOTROPY SEARCHES IN DATA OF THE PIERRE AUGER OBSERVATORY  

SciTech Connect (OSTI)

A thorough search for large-scale anisotropies in the distribution of arrival directions of cosmic rays detected above 10{sup 18} eV at the Pierre Auger Observatory is reported. For the first time, these large-scale anisotropy searches are performed as a function of both the right ascension and the declination and expressed in terms of dipole and quadrupole moments. Within the systematic uncertainties, no significant deviation from isotropy is revealed. Upper limits on dipole and quadrupole amplitudes are derived under the hypothesis that any cosmic ray anisotropy is dominated by such moments in this energy range. These upper limits provide constraints on the production of cosmic rays above 10{sup 18} eV, since they allow us to challenge an origin from stationary galactic sources densely distributed in the galactic disk and emitting predominantly light particles in all directions.

Abreu, P.; Andringa, S. [LIP and Instituto Superior Tecnico, Technical University of Lisbon (Portugal); Aglietta, M. [Istituto di Fisica dello Spazio Interplanetario (INAF), Universita di Torino and Sezione INFN, Torino (Italy); Ahlers, M. [University of Wisconsin, Madison, WI (United States); Ahn, E. J. [Fermilab, Batavia, IL (United States); Albuquerque, I. F. M. [Universidade de Sao Paulo, Instituto de Fisica, Sao Paulo, SP (Brazil); Allard, D. [Laboratoire AstroParticule et Cosmologie (APC), Universite Paris 7, CNRS-IN2P3, Paris (France); Allekotte, I. [Centro Atomico Bariloche and Instituto Balseiro (CNEA-UNCuyo-CONICET), San Carlos de Bariloche (Argentina); Allen, J. [New York University, New York, NY (United States); Allison, P. [Ohio State University, Columbus, OH (United States); Almela, A. [Universidad Tecnologica Nacional - Facultad Regional Buenos Aires, Buenos Aires (Argentina); Castillo, J. Alvarez [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico); Alvarez-Muniz, J. [Universidad de Santiago de Compostela (Spain); Alves Batista, R. [Universidade Estadual de Campinas, IFGW, Campinas, SP (Brazil); Ambrosio, M.; Aramo, C. [Universita di Napoli 'Federico II' and Sezione INFN, Napoli (Italy); Aminaei, A. [IMAPP, Radboud University Nijmegen (Netherlands); Anchordoqui, L. [University of Wisconsin, Milwaukee, WI (United States); Antici'c, T. [Rudjer Boskovi'c Institute, 10000 Zagreb (Croatia); Arganda, E. [IFLP, Universidad Nacional de La Plata and CONICET, La Plata (Argentina); Collaboration: Pierre Auger Collaboration; and others

2013-01-01T23:59:59.000Z

363

The Cosmic Ray p+He energy spectrum in the 3-3000 TeV energy range measured by ARGO-YBJ  

E-Print Network [OSTI]

The ARGO-YBJ experiment is a full coverage air shower detector operated at the Yangbajing International Cosmic Ray Observatory. The detector has been in stable data taking in its full configuration since November 2007 to February 2013. The high altitude and the high segmentation and spacetime resolution offer the possibility to explore the cosmic ray energy spectrum in a very wide range, from a few TeV up to the PeV region. The high segmentation allows a detailed measurement of the lateral distribution, which can be used in order to discriminate showers produced by light and heavy elements. In this work we present the measurement of the cosmic ray light component spectrum in the energy range 3-3000 TeV. The analysis has been carried out by using a two-dimensional unfolding method based on the Bayes' theorem.

Mari, S M

2015-01-01T23:59:59.000Z

364

A NOVEL APPROACH IN THE WEAKLY INTERACTING MASSIVE PARTICLE QUEST: CROSS-CORRELATION OF GAMMA-RAY ANISOTROPIES AND COSMIC SHEAR  

SciTech Connect (OSTI)

Both cosmic shear and cosmological gamma-ray emission stem from the presence of dark matter (DM) in the universe: DM structures are responsible for the bending of light in the weak-lensing regime and those same objects can emit gamma rays, either because they host astrophysical sources (active galactic nuclei or star-forming galaxies) or directly by DM annihilations (or decays, depending on the properties of the DM particle). Such gamma rays should therefore exhibit strong correlation with the cosmic shear signal. In this Letter, we compute the cross-correlation angular power spectrum of cosmic shear and gamma rays produced by the annihilation/decay of weakly interacting massive particle DM, as well as by astrophysical sources. We show that this observable provides novel information on the composition of the extragalactic gamma-ray background (EGB), since the amplitude and shape of the cross-correlation signal strongly depend on which class of sources is responsible for the gamma-ray emission. If the DM contribution to the EGB is significant (at least in a definite energy range), although compatible with current observational bounds, its strong correlation with the cosmic shear makes such signal potentially detectable by combining Fermi Large Area Telescope data with forthcoming galaxy surveys, like the Dark Energy Survey and Euclid. At the same time, the same signal would demonstrate that the weak-lensing observables are indeed due to particle DM matter and not to possible modifications of general relativity.

Camera, Stefano [CENTRA, Instituto Superior Tecnico, Universidade Tecnica de Lisboa, Lisboa (Portugal); Fornasa, Mattia [School of Physics and Astronomy, University of Nottingham, Nottingham (United Kingdom); Fornengo, Nicolao; Regis, Marco [Dipartimento di Fisica, Universita di Torino and INFN, Torino (Italy)

2013-07-01T23:59:59.000Z

365

Resolving the 1040 keV cosmic X-ray background with constellation-X  

Science Journals Connector (OSTI)

The energy density of the Cosmic X-ray background (XRB) peaks around 30 keV (see Figure 1) an energy not yet probed by focussing imaging instruments. The first hard X-ray telescope due to fly on a space mission will be that on board Constellation-X. The imaging capability besides providing an improvement of several orders of magnitude in sensitivity over current passively collimated detectors will permit for the first time to resolve a fraction of the XRB at this most crucial energy. Synthesis models of the XRB based on obscured AGN predict that at least 40% of the 1040 keV XRB will be resolved by Constellation-X.

Giorgio Matt; Fulvio Pompilio; Fabio La Franca

2001-01-01T23:59:59.000Z

366

Resolving the 10-40 keV Cosmic X-ray Background with Constellation-X  

E-Print Network [OSTI]

The energy density of the Cosmic X-ray background (XRB) peaks around 30 keV (see Figure 1), an energy not yet probed by focussing imaging instruments. The first hard X-ray telescope due to fly on a space mission will be that on board Constellation-X. The imaging capability, besides providing an improvement of several orders of magnitude in sensitivity over current passively collimated detectors, will permit for the first time to resolve a fraction of the XRB at this most crucial energy. Synthesis models of the XRB based on obscured AGN predict that at least 40% of the 10-40 keV XRB will be resolved by Constellation-X.

Giorgio Matt; Fulvio Pompilio; Fabio La Franca

2000-07-08T23:59:59.000Z

367

The effects of coronal mass ejection on galactic cosmic rays in the high latitude heliosphere: Observations from Ulysses` first orbit  

SciTech Connect (OSTI)

During its first solar orbit the Ulysses spacecraft detected several coronal mass ejections (CMEs) at high heliographic latitudes. The authors present first observations on the effects of these high latitude CMEs on galactic cosmic rays (GCRs) using measurements from the Kiel Electron Telescope (KET) which is part of the Cosmic Ray and Solar Particle Investigation (COSPIN) experiment, the Los Alamos SWOOPS (Solar Wind Observations Over the Poles of the Sun) experiment and the magnetic field experiments. They find the passage of these CMEs over the spacecraft to be associated with short term decreases of GCR intensities The relatively weak shocks in these events, driven by the CMEs` over-expansion, had no strong influence on the GCRs. The intensity minimums of GCRs occurred on closed magnetic field lines inside the CMEs themselves as indicated by bidirectional fluxes of suprathermal electrons. Short episodes of intensity increases of GCRs inside CMEs at times when the bidirectional fluxes of suprathermal electrons disappeared, can be interpreted as evidence that GCRs can easily access the interior of those CMEs in which open magnetic field lines are embedded.

Bothmer, V.; Heber, B.; Kunow, H.; Mueller-Mellin, R.; Wibberenz, G. [Univ. of Kiel (Germany). Institut fuer Kernphysik; Gosling, J.T. [Los Alamos National Lab., NM (United States); Balogh, A. [Imperial College, London (United Kingdom). Blackett Lab.; Raviart, A. [CEA, Gif-sur-Yvette (France). Service d`Astrophysique; Paizis, C. [Univ. di Milano (Italy). Istituto di Fisica Cosmica CNR

1997-10-01T23:59:59.000Z

368

Probing the origin of cosmic rays with extremely high energy neutrinos using the IceCube Observatory  

Science Journals Connector (OSTI)

We have searched for extremely high energy neutrinos using data taken with the IceCube detector between May 2010 and May 2012. Two neutrino-induced particle shower events with energies around 1PeV were observed, as reported previously. In this work, we investigate whether these events could originate from cosmogenic neutrinos produced in the interactions of ultrahigh energy cosmic rays with ambient photons while propagating through intergalactic space. Exploiting IceCubes large exposure for extremely high energy neutrinos and the lack of observed events above 100PeV, we can rule out the corresponding models at more than 90% confidence level. The model-independent quasidifferential 90%C.L. upper limit, which amounts to E2??e+??+??=1.210-7??GeV?cm-2?s-1?sr-1 at 1EeV, provides the most stringent constraint in the energy range from 10PeV to 10EeV. Our observation disfavors strong cosmological evolution of the highest energy cosmic-ray sources such as the Fanaroff-Riley type II class of radio galaxies.

M. G. Aartsen et al. (IceCube Collaboration)

2013-12-16T23:59:59.000Z

369

The Origin of the Cosmic Soft X-Ray Background: Optical Identification of an Extremely Deep ROSAT Survey  

E-Print Network [OSTI]

We present the results of the deepest optically identified X-ray survey yet made. The X-ray survey was made with the ROSAT PSPC and reaches a flux limit of 1.6x10^-15 erg cm^-2 s^-1 (0.5--2.0 keV). Above a flux limit of 2x10^-15 erg cm^-2 s^-1 we define a complete sample of 70 sources of which 59 are identified. Some (5) other sources have tentative identifications and in a further 4 the X-ray error-boxes are blank to R=23 mag. At the brighter flux levels (>= 10^-14 erg cm^-2 s^-1) we confirm the results of previous less deep X-ray surveys with 84% of the sources begin QSOs. At fainter fluxes, however, the survey is dominated by a population of galaxies with narrow optical emission lines (NELGs). In addition, a number of groups and clusters of galaxies are found at intermediate fluxes. Most of these are poor systems of low X-ray luminosity and are generally found at redshifts of > 0.3. Their numbers are consistent with a zero evolutionary scenario, in contrast to the situation for high luminosity clusters at the same redshift. We discuss the significance of these results to the determination of the cosmic soft X-ray background (XRB) and show that at 2x10^-15 erg cm^-2 s^-1, we have resolved more than 50% of the background. We also briefly consider the probable importance of NELG objects to the residual background and look at some of the properties of these unusual objects.

I. M. McHardy; L. R. Jones; M. R. Merrifield; K. O. Mason; R. G. Abraham; A. M. Newsam; G. B. Dalton; F. Carrera; P. J. Smith; M. Rowan-Robinson; G. A. Wegner; T. J. Ponman; H. J. Lehto; G. Branduardi-Raymont; G. A. Luppino; G. Efstathiou; D. J. Allan; J. J. Quenby

1997-10-28T23:59:59.000Z

370

E-Print Network 3.0 - all-sky cosmic explorer Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

monitor with sharp timing capability. This proved decisive in demonstrating that gamma ray... Chapter 8 Cosmic Rays 8.1 Composition and energy distribution Cosmic rays can be...

371

Reconstructing the Cosmic Expansion History up to Redshift z=6.29 with the Calibrated Gamma-Ray Bursts  

E-Print Network [OSTI]

Recently, Gamma-Ray Bursts (GRBs) were proposed to be a complementary cosmological probe to type Ia supernovae (SNIa). GRBs have been advocated to be standard candles since several empirical GRB luminosity relations were proposed as distance indicators. However, there is a so-called circularity problem in the direct use of GRBs. Recently, a new idea to calibrate GRBs in a completely cosmology independent manner has been proposed, and the circularity problem can be solved. In the present work, following the method proposed by Liang {\\it et al.}, we calibrate 70 GRBs with the Amati relation using 307 SNIa. Then, following the method proposed by Shafieloo {\\it et al.}, we smoothly reconstruct the cosmic expansion history up to redshift $z=6.29$ with the calibrated GRBs. We find some new features in the reconstructed results.

Hao Wei; Shuang Nan Zhang

2009-08-31T23:59:59.000Z

372

The Spectral Break Near TeV of $e^\\pm$ Cosmic Rays - Standard Physics or Dark Matter Origin?  

E-Print Network [OSTI]

The complex spectra of high energy ${\\rm e^\\pm}$ cosmic rays (CRs) observed near Earth are those expected from standard model physics. In particular, the observed hardening of their spectra with increasing energy reported by the AMS-02 collaboration can be produced by the transition of their energy-loss by inverse Compton scattering off Galactic light from the Thomson to the Klein-Nishina regime. The "cut-off" near TeV in the combined ${\\rm e^\\pm}$ flux observed with H.E.S.S can be due to pair production in ${\\rm e^\\pm}\\gamma$ collisions in source rather than a bump produced by the decay/annihilation of dark matter particles with a mass of $\\sim$TeV. Beyond this "cutoff", the $e^\\pm$ CRs are mostly produced by the decay of mesons from hadronic collisions of CR protons in/near source with a positron fraction $\\sim 0.57$.

Dado, Shlomo

2015-01-01T23:59:59.000Z

373

Anisotropy and chemical composition of ultra-high energy cosmic rays using arrival directions measured by the Pierre Auger Observatory  

DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

The Pierre Auger Collaboration has reported evidence for anisotropy in the distribution of arrival directions of the cosmic rays with energies E > Eth = 5.5 x 1019 eV. These show a correlation with the distribution of nearby extragalactic objects, including an apparent excess around the direction of Centaurus A. If the particles responsible for these excesses at E > Eth are heavy nuclei with charge Z, the proton component of the sources should lead to excesses in the same regions at energies E/Z. We here report the lack of anisotropies in these directions at energies above Eth/Z (for illustrative values of Z = 6,13,26). If the anisotropies above Eth are due to nuclei with charge Z, and under reasonable assumptions about the acceleration process, these observations imply stringent constraints on the allowed proton fraction at the lower energies.

Abreu, P [Lisbon, IST; Aglietta, M [IFSI, Turin; Ahn, E J [Fermilab; Albuquerque, I F.M. [Sao Paulo U.; Allard, D [APC, Paris; Allekotte, I [Centro Atomico Bariloche; Allen, J [New York U.; Allison, P [Ohio State U.; Alvarez Castillo, J [Mexico U., ICN; Alvarez-Muniz, J [Santiago de Compostela U.; Ambrosio, M [Napoli Seconda U.; INFN, Naples; Nijmegen U., IMAPP

2011-06-17T23:59:59.000Z

374

Reconstruction of Longitudinal Profiles of Ultra-High Energy Cosmic Ray Showers from Fluorescence and Cherenkov Light Measurements  

E-Print Network [OSTI]

We present a new method for the reconstruction of the longitudinal profile of extensive air showers induced by ultra-high energy cosmic rays. In contrast to the typically considered shower size profile, this method employs directly the ionization energy deposit of the shower particles in the atmosphere. Due to universality of the energy spectra of electrons and positrons, both fluorescence and Cherenkov light can be used simultaneously as signal to infer the shower profile from the detected light. The method is based on an analytic least-square solution for the estimation of the shower profile from the observed light signal. Furthermore, the extrapolation of the observed part of the profile with a Gaisser-Hillas function is discussed and the total statistical uncertainty of shower parameters like total energy and shower maximum is calculated.

M. Unger; B. R. Dawson; R. Engel; F. Schssler; R. Ulrich

2008-01-28T23:59:59.000Z

375

The Impact of Star Formation and Gamma-Ray Burst Rates at High Redshift on Cosmic Chemical Evolution and Reionization  

E-Print Network [OSTI]

Recent observations in the total luminosity density have led to significant progress in establishing the star formation rate (SFR) at high redshift. Concurrently observed gamma-ray burst rates have also been used to extract the SFR at high redshift. The SFR in turn can be used to make a host of predictions concerning the ionization history of the Universe, the chemical abundances, and supernova rates. We compare the predictions made using a hierarchical model of cosmic chemical evolution based on three recently proposed SFRs: two based on extracting the SFR from the observed gamma-ray burst rate at high redshift, and one based on the observed galaxy luminosity function at high redshift. Using the WMAP/Planck data on the optical depth and epoch of reionization, we find that only the SFR inferred from gamma-ray burst data at high redshift suffices to allow a single mode (in the initial mass function) of star formation which extends from z = 0 to redshifts > 10. For the case of the more conservative SFR based on...

Vangioni, E; Prestegard, T; Silk, J; Petitjean, P; Mandic, V

2014-01-01T23:59:59.000Z

376

THE FERMI BUBBLES. II. THE POTENTIAL ROLES OF VISCOSITY AND COSMIC-RAY DIFFUSION IN JET MODELS  

SciTech Connect (OSTI)

The origin of the Fermi bubbles recently detected by the Fermi Gamma-ray Space Telescope in the inner Galaxy is mysterious. In the companion paper Guo and Mathews (Paper I), we use hydrodynamic simulations to show that they could be produced by a recent powerful active galactic nucleus (AGN) jet event. Here, we further explore this scenario to study the potential roles of shear viscosity and cosmic-ray (CR) diffusion on the morphology and CR distribution of the bubbles. We show that even a relatively low level of viscosity ({mu}{sub visc} {approx}> 3 g cm{sup -1} s{sup -1}, or {approx}0.1%-1% of Braginskii viscosity in this context) could effectively suppress the development of Kelvin-Helmholtz instabilities at the bubble surface, resulting in smooth bubble edges as observed. Furthermore, viscosity reduces circulating motions within the bubbles, which would otherwise mix the CR-carrying jet backflow near bubble edges with the bubble interior. Thus viscosity naturally produces an edge-favored CR distribution, an important ingredient to produce the observed flat gamma-ray surface brightness distribution. Generically, such a CR distribution often produces a limb-brightened gamma-ray intensity distribution. However, we show that by incorporating CR diffusion that is strongly suppressed across the bubble surface (as inferred from sharp bubble edges) but is close to canonical values in the bubble interior, we obtain a reasonably flat gamma-ray intensity profile. The similarity of the resulting CR bubble with the observed Fermi bubbles strengthens our previous result in Paper I that the Fermi bubbles were produced by a recent AGN jet event. Studies of the nearby Fermi bubbles may provide a unique opportunity to study the potential roles of plasma viscosity and CR diffusion on the evolution of AGN jets and bubbles.

Guo Fulai; Mathews, William G. [UCO/Lick Observatory, Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Dobler, Gregory [Kavli Institute for Theoretical Physics, University of California, Santa Barbara Kohn Hall, Santa Barbara, CA 93106 (United States); Oh, S. Peng, E-mail: fulai@ucolick.org [Department of Physics, University of California, Santa Barbara Kohn Hall, Santa Barbara, CA 93106 (United States)

2012-09-10T23:59:59.000Z

377

Catalog of cosmic gamma-ray bursts from the KONUS experiment data  

Science Journals Connector (OSTI)

The fourth and concluding part of the Catalog contains information on 20 gamma-ray bursts detected in the KONUS experiment on the...

E. P. Mazets; S. V. Golenetskii; V. N. Ilyinskii

1981-11-01T23:59:59.000Z

378

Solar panels as air Cherenkov detectors for extremely high energy cosmic rays  

E-Print Network [OSTI]

Increasing interest towards the observation of the highest energy cosmic rayshas motivated the development of new detection techniques. The properties ofthe Cherenkov photon pulse emitted in the atmosphere by these very rareparticles indicate low-cost semiconductor detectors as good candidates fortheir optical read-out. The aim of this paper is to evaluate the viability of solar panels for thispurpose. The experimental framework resulting from measurements performed withsuitably-designed solar cells and large conventional photovoltaic areas ispresented. A discussion on the obtained and achievable sensitivities follows.

Cecchini, S; Esposti, L D; Giacomelli, G; Guerra, M; Lax, I; Mandrioli, G; Parretta, A; Sarno, A; Schioppo, R; Sorel, M; Spurio, M

2000-01-01T23:59:59.000Z

379

Evidences of high energy protons with energies beyond 0.4 GeV in the solar particle spectrum as responsible for the cosmic rays solar diurnal anisotropy  

E-Print Network [OSTI]

Analysis on the daily variations of cosmic ray muons with $E_{\\mu}\\geq 0.2 GeV$ based on the data of two directional muon telescopes at sea level and with a rigidity of response to cosmic proton spectrum above 0.4 GV is presented. The analysis covers two months of observations and in 60% of days, abrupt transitions between a low to a high muon intensity and vice-verse is observed, the period of high muon intensity is from $\\sim 8.0h$ up to $\\sim 19.0h$ (local time) and coincides with the period when the interplanetary magnetic field (IMF) lines overtake the Earth. This behavior strongly suggest that the high muon intensity is due to a contribution of solar protons (ions) on the muon intensity produced by the galactic cosmic rays, responsible for the low muon intensity. This implies that the solar particle spectrum extends to energies beyond 1 GeV. We show that this picture can explain the solar daily variation origin, and it is a most accurate scenario than the assumption of corotating galactic cosmic ray with the IMF lines, specially in the high rigidity region. Obtained results are consistent with the data reported in others papers. Some aspects on the sensitivity of our muon telescopes are also presented.

C. E. Navia; C. R. A. Augusto; M. B. Robba; K. H. Tsui

2007-06-26T23:59:59.000Z

380

The Elemental Composition of High-Energy Cosmic Rays: Measurements with TRACER  

E-Print Network [OSTI]

TRACER ('Transition Radiation Array for Cosmic Energetic Radiation') is a balloon borne instrument that has been developed to directly measure the composition and energy spectra of individual heavy elements up to 10^15 eV per particle. TRACER achieves a large geometric factor (5 m^2 sr) through the use of a Transition Radiation Detector utilizing arrays of single wire proportional tubes. TRACER has measured the energy spectra of the elements O, Ne, Mg, Si, S, Ar, Ca, and Fe. The energy spectra reach energies in excess of 10^14 eV per particle and exhibit nearly the same spectral index (2.65 +/- 0.05) for all elements.

P. J. Boyle

2008-10-16T23:59:59.000Z

Note: This page contains sample records for the topic "int cosmic ray" from the National Library of EnergyBeta (NLEBeta).
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381

Direct constraints on diffusion models from cosmic-ray positron data: Excluding the minimal model for dark matter searches  

Science Journals Connector (OSTI)

Galactic cosmic-ray (CR) transport parameters are usually constrained by the boron-to-carbon ratio. This procedure is generically plagued with degeneracies between the diffusion coefficient and the vertical extent of the Galactic magnetic halo. The latter is of paramount importance for indirect dark matter (DM) searches because it fixes the amount of DM annihilation or decay that contributes to the local antimatter CR flux. These degeneracies could be broken by using secondary radioactive species, but the current data still have large error bars, and this method is extremely sensitive to the very local interstellar medium properties. Here, we propose to use the low-energy CR positrons in the GeV range as another direct constraint on diffusion models. We show that the PAMELA data disfavor small diffusion halo (L?3??kpc) and large diffusion slope models and exclude the minimal configuration [Maurin etal. Astrophys. J. 555, 585 (2001); Donato etal. Phys. Rev. D 69, 063501 (2004)] widely used in the literature to bracket the uncertainties in the DM signal predictions. This is complementary to indirect constraints (diffuse radio and gamma-ray emissions) and has a strong impact on DM searches. Indeed, this makes the antiproton constraints more robust while enhancing the discovery/exclusion potential of current and future experiments, like AMS-02 and GAPS, especially in the antiproton and antideuteron channels.

Julien Lavalle; David Maurin; Antje Putze

2014-10-15T23:59:59.000Z

382

Direct constraints on diffusion models from cosmic-ray positron data: Excluding the Minimal model for dark matter searches  

E-Print Network [OSTI]

Galactic Cosmic-ray (CR) transport parameters are usually constrained by the boron-to-carbon ratio. This procedure is generically plagued with degeneracies between the diffusion coefficient and the vertical extent of the Galactic magnetic halo. The latter is of paramount importance for indirect dark matter (DM) searches, because it fixes the amount of DM annihilation or decay that contributes to the local antimatter CR flux. These degeneracies could be broken by using secondary radioactive species, but the current data still have large error bars, and this method is extremely sensitive to the very local interstellar medium (ISM) properties. Here, we propose to use the low-energy CR positrons in the GeV range as another direct constraint on diffusion models. We show that the PAMELA data disfavor small diffusion halo ($L\\lesssim 3$ kpc) and large diffusion slope models, and exclude the minimal ({\\em min}) configuration (Maurin et al. 2001, Donato et al. 2004) widely used in the literature to bracket the uncertainties in the DM signal predictions. This is complementary to indirect constraints (diffuse radio and gamma-ray emissions) and has strong impact on DM searches. Indeed this makes the antiproton constraints more robust while enhancing the discovery/exclusion potential of current and future experiments, like AMS-02 and GAPS, especially in the antiproton and antideuteron channels.

Julien Lavalle; David Maurin; Antje Putze

2015-01-22T23:59:59.000Z

383

Non-thermal Cosmic Backgrounds from Blazars: the contribution to the CMB, X-ray and gamma-ray Backgrounds  

E-Print Network [OSTI]

We present a new assessment of the contribution of Blazars to the extragalactic background radiation across the e.m. spectrum. Our calculations rely on deep Blazar radio counts that we derived combining several multifrequency surveys. The integrated Blazar emission yields a broad-band non-thermal background that in some parts of the e.m. spectrum dominates the extragalactic brightness. Blazars are the main point-like contributors to the CMB. Their integrated emission causes an apparent T increase of 5-50 muK in the 50-250 GHz range. The CMB fluctuation spectrum is sensibly contaminated at l>300, for a Poissonian source distribution, or at lower l values if spatial clustering is present. We estimate that well over 100,000 Blazars will produce a significant signal in the PLANCK CMB anisotropy maps. Because of the microwave-Xray flux correlation, these sources are expected to have flux > a few 10^{-15} erg/s in the soft X-ray band. Thus, a large fraction of the foreground sources in CMB anisotropy maps could be identified and removed using a multi frequency approach, provided that a sufficiently deep all sky X-ray survey will be available. We further show that Blazars are a major constituent of all high-E extragalactic backgrounds. Their contribution is 11-12% at X-ray frequencies and possibly 100% in the 0.5-50 MeV band. At E>100 MeV, the Blazar collective emission, obtained extrapolating their integrated micro-wave flux to the gamma-ray band using the SED of EGRET detected sources, over-predicts the extragalactic background by a large factor, implying that Blazars not only dominate the gamma-ray sky but also that their average duty cycle at these frequencies must be rather low. We also find that Blazars of the HBL type may produce a significant amount of flux at TeV energies.

P. Giommi; S. Colafrancesco; E. Cavazzuti; M. Perri; C. Pittori

2005-08-01T23:59:59.000Z

384

Ultra High Energy Cosmic Rays, Z-Shower and Neutrino Astronomy by Horizontal-Upward Tau Air-Showers  

E-Print Network [OSTI]

Ultra High Cosmic Rays (UHECR) Astronomy may be correlated to a primary parental Neutrino Astronomy: indeed any far BL Lac Jet or GRB, sources of UHECR, located at cosmic edges, may send its signal, overcoming the severe GZK cut-off, by help of UHE ZeV energetic neutrino primary. These UHE neutrino scattering on relic light ones (spread on wide Hot Local Groups Halos) maybe fine-tuned : E_(nu) =(M_Z)^2/m_(nu) = 4 10^(22) eV *((0.1eV)/m_(nu)), to combine at once the observed light neutrino masses and the UHECR spectra, leading to a relativistic Z-Shower in Hot Dark Halos (e few tens Mpc wide) whose final nuclear component traces the UHECR event on Earth. Therefore UHECR (with no longer volme GZK constrains) may point to far BL Lac sources. This Z-Burst (Z-Shower) model calls for large neutrino fluxes. Even if Nature do not follow the present Z-model, UHECR while being cut-off by Big Bang Radiation, must produce a minimal UHE neutrino flux, the GZK neutrino secondaries. For both reasons such UHE Neutrino Astronomy must be tested on Earth. Lowest High Energy Astronomy is searched by AMANDA, ANTARES underground deterctors by muons tracks. We suggest a complementary higher energy Neutrino Tau Astronomy inducing Horizontal and Upward Tau AirShowers. Possible early evidence of such a New Neutrino UPTAUs (Upward Tau Showers at PeVs energies) Astronomy may be in BATSE records of Upward Terrestrial Gamma Flashes. Future signals must be found in detectors as EUSO, seeking Upward-Horizontal events: indeed even minimal, guaranteed, GZK neutrino fluxes may be better observed if EUSO threshold reaches 10^(19) eV by enlarging its telescope size.

D. Fargion

2003-06-24T23:59:59.000Z

385

On active galactic nuclei as sources of ultra-high energy cosmic rays  

Science Journals Connector (OSTI)

......possible inconsistencies in energy calibration and angular resolution...X-rays are relevant to high energy particle acceleration. By...has been operating stably in Argentina since 2004, using a hybrid...comprised of 27 events with energies above 5.7 1019 eV from an......

M. R. George; A. C. Fabian; W. H. Baumgartner; R. F. Mushotzky; J. Tueller

2008-07-01T23:59:59.000Z

386

The Chandra Deep FieldNorth Survey and the cosmic Xray background  

Science Journals Connector (OSTI)

...the University of Hawaii, the University of Wisconsin, the Massachusetts Institute of Technology, the California Institute of Technology...B. 1962 Evidence for X-rays from sources outside the solar system. Phys. Rev. Lett. 9, 439{443. Giacconi, R...

2002-01-01T23:59:59.000Z

387

33RD INTERNATIONAL COSMIC RAY CONFERENCE, RIO DE JANEIRO 2013 THE ASTROPARTICLE PHYSICS CONFERENCE  

E-Print Network [OSTI]

a good estimation of the energy of the primary cos- mic ray particle. The electromagnetic energy is proportional to the energy dissipated. Whereas the global process of energy deposit by charged particles a sizeable frac- tion of the primary electron energy may deposit their en- ergy at far distances from

Boyer, Edmond

388

The Theoretical Power Law Exponent for Electron and Positron Cosmic Rays: A Comment on the Recent Letter of the AMS Collaboration  

E-Print Network [OSTI]

In a recent letter, the AMS collaboration reported the detailed and extensive data concerning the distribution in energy of electron and positron cosmic rays. A central result of the experimental work resides in the energy regime $30\\ {\\rm GeV} < E < 1\\ {\\rm TeV}$ wherein the power law exponent of the energy distribution is measured to be $\\alpha ({\\rm experiment})=3.17$. In virtue of the Fermi statistics obeyed by electrons and positrons, a theoretical value was predicted as $\\alpha ({\\rm theory})=3.151374$ in very good agreement with experimental data. The consequences of this agreement between theory and experiment concerning the sources of cosmic ray electrons and positrons are briefly explored.

Swain, A Widom J

2015-01-01T23:59:59.000Z

389

Constraints on the flux of primary cosmic-ray photons at energies E > 10^18 eV from Yakutsk muon data  

E-Print Network [OSTI]

Comparing the signals measured by the surface and underground scintillator detectors of the Yakutsk Extensive Air Shower Array, we place upper limits on the integral flux and the fraction of primary cosmic-ray photons with energies E > 10^18 eV, E > 2*10^18 eV and E > 4*10^18 eV. The large collected statistics of the showers measured by large-area muon detectors provides a sensitivity to photon fractions energies.

A. V. Glushkov; I. T. Makarov; M. I. Pravdin; I. E. Sleptsov; D. S. Gorbunov; G. I. Rubtsov; S. V. Troitsky

2009-07-02T23:59:59.000Z

390

A New Method to Reconstruct the Energy and Determine the Composition of Cosmic Rays from the Measurement of Cherenkov Light and Particle Densities in Extended Air Showers  

E-Print Network [OSTI]

A Monte-Carlo study is presented using ground based measurements of the electromagnetic part of showers initiated in the atmosphere by high energetic cosmic rays to reconstruct energy and mass of primary particles with energies above 300 TeV. With two detector arrays measuring Cherenkov light and particle densities as realized in the HEGRA experiment shower properties are reconstructed and interpreted to determine energy and energy per nucleon of the primary particle.

A. Lindner

1996-11-21T23:59:59.000Z

391

Cosmic Abundance of Boron  

Science Journals Connector (OSTI)

... of low energy cosmic rays might be the necessary mechanism to produce the additional boron.Boron-10 is produced by the reaction 13C(p,a)10B, which has a Q value ...

A. G. W. CAMERON; S. A. COLGATE; L. GROSSMAN

1973-05-25T23:59:59.000Z

392

Biomarker Response to Galactic Cosmic Ray-Induced NOx and the Methane Greenhouse Effect in the Atmosphere of an Earthlike Planet Orbiting an M-Dwarf Star  

E-Print Network [OSTI]

Planets orbiting in the habitable zone (HZ) of M-Dwarf stars are subject to high levels of galactic cosmic rays (GCRs) which produce nitrogen oxides in earthlike atmospheres. We investigate to what extent this NOx may modify biomarker compounds such as ozone (O3) and nitrous oxide (N2O), as well as related compounds such as water (H2O) (essential for life) and methane (CH4) (which has both abiotic and biotic sources) . Our model results suggest that such signals are robust, changing in the M-star world atmospheric column by up to 20% due to the GCR NOx effects compared to an M-star run without GCR effects and can therefore survive at least the effects of galactic cosmic rays. We have not however investigated stellar cosmic rays here. CH4 levels are about 10 times higher than on the Earth related to a lowering in hydroxyl (OH) in response to changes in UV. The increase is less than reported in previous studies. This difference arose partly because we used different biogenic input. For example, we employed 23% ...

Grenfell, J L; Patzer, B; Rauer, H; Segura, A; Stadelmann, A; Stracke, B; Titz, R; Von Paris, P; Grenfell, John Lee; Griessmeier, Jean-Mathias; Patzer, Beate; Rauer, Heike; Segura, Antigona; Stadelmann, Anja; Stracke, Barbara; Titz, Ruth; Paris, Philip von

2007-01-01T23:59:59.000Z

393

Anisotropy and chemical composition of ultra-high energy cosmic rays using arrival directions measured by the Pierre Auger Observatory  

SciTech Connect (OSTI)

The Pierre Auger Collaboration has reported evidence for anisotropy in the distribution of arrival directions of the cosmic rays with energies E > Eth = 5.5 x 1019 eV. These show a correlation with the distribution of nearby extragalactic objects, including an apparent excess around the direction of Centaurus A. If the particles responsible for these excesses at E > Eth are heavy nuclei with charge Z, the proton component of the sources should lead to excesses in the same regions at energies E/Z. We here report the lack of anisotropies in these directions at energies above Eth/Z (for illustrative values of Z = 6,13,26). If the anisotropies above Eth are due to nuclei with charge Z, and under reasonable assumptions about the acceleration process, these observations imply stringent constraints on the allowed proton fraction at the lower energies.

Abreu, P [Lisbon, IST; Aglietta, M [IFSI, Turin; Ahn, E J [Fermilab; Albuquerque, I F.M. [Sao Paulo U.; Allard, D [APC, Paris; Allekotte, I [Centro Atomico Bariloche; Allen, J [New York U.; Allison, P [Ohio State U.; Alvarez Castillo, J [Mexico U., ICN; Alvarez-Muniz, J [Santiago de Compostela U.; Ambrosio, M [Napoli Seconda U.; INFN, Naples; Nijmegen U., IMAPP

2011-06-17T23:59:59.000Z

394

Ankle-like Feature in the Energy Spectrum of Light Elements of Cosmic Rays Observed with KASCADE-Grande  

E-Print Network [OSTI]

Recent results of the KASCADE-Grande experiment provided evidence for a mild knee-like structure in the all-particle spectrum of cosmic rays at $E = 10^{16.92 \\pm 0.10} \\, \\mathrm{eV}$, which was found to be due to a steepening in the flux of heavy primary particles. The spectrum of the combined components of light and intermediate masses was found to be compatible with a single power law in the energy range from $10^{16.3} \\, \\mathrm{eV}$ to $10^{18} \\, \\mathrm{eV}$. In this paper, we present an update of this analysis by using data with increased statistics, originating both from a larger data set including more recent measurements and by using a larger fiducial area. In addition, optimized selection criteria for enhancing light primaries are applied. We find a spectral feature for light elements, namely a hardening at $E = 10^{17.08 \\pm 0.08} \\, \\mathrm{eV}$ with a change of the power law index from $-3.25 \\pm 0.05$ to $-2.79 \\pm 0.08$.

Apel, W D; Bekk, K; Bertaina, M; Blmer, J; Bozdog, H; Brancus, I M; Cantoni, E; Chiavassa, A; Cossavella, F; Daumiller, K; de Souza, V; Di Pierro, F; Doll, P; Engel, R; Engler, J; Finger, M; Fuchs, B; Fuhrmann, D; Gils, H J; Glasstetter, R; Grupen, C; Haungs, A; Heck, D; Hrandel, J R; Huber, D; Huege, T; Kampert, K -H; Kang, D; Klages, H O; Link, K; ?uczak, P; Ludwig, M; Mathes, H J; Mayer, H J; Melissas, M; Milke, J; Mitrica, B; Morello, C; Oehlschlger, J; Ostapchenko, S; Palmieri, N; Petcu, M; Pierog, T; Rebel, H; Roth, M; Schieler, H; Schoo, S; Schrder, F G; Sima, O; Toma, G; Trinchero, G C; Ulrich, H; Weindl, A; Wochele, J; Wommer, M; Zabierowski, J; 10.1103/PhysRevD.87.081101

2013-01-01T23:59:59.000Z

395

A Detailed Study of FDIRC Prototype with Waveform Digitizing Electronics in Cosmic Ray Telescope Using 3D Tracks  

SciTech Connect (OSTI)

We present a detailed study of a novel Cherenkov imaging detector called the Focusing DIRC (FDIRC) with waveform digitizing electronics. In this test study, the FDIRC prototype has been instrumented with seven Hamamatsu H-8500 MaPMTs. Waveforms from {approx}450 pixels are digitized with waveform sampling electronics based on the BLAB2 ASIC, operating at a sampling speed of {approx}2.5 GSa/s. The FDIRC prototype was tested in a large cosmic ray telescope (CRT) providing 3D muon tracks with {approx}1.5 mrad angular resolution and muon energy of E{sub muon} > 1.6 GeV. In this study we provide a detailed analysis of the tails in the Cherenkov angle distribution as a function of various variables, compare experimental results with simulation, and identify the major contributions to the tails. We demonstrate that to see the full impact of these tails on the Cherenkov angle resolution, it is crucial to use 3D tracks, and have a full understanding of the role of ambiguities. These issues could not be fully explored in previous FDIRC studies where the beam was perpendicular to the quartz radiator bars. This work is relevant for the final FDIRC prototype of the PID detector at SuperB, which will be tested this year in the CRT setup.

Nishimura, K.; Dey, B.; /Hawaii U. /UC, Riverside; Aston, D.; Leith, D.W.G.S.; Ratcliff, B.; /SLAC; Roberts, D.; /Maryland U.; Ruckman, L.; /Hawaii U.; Shtol, D.; /Novosibirsk, IYF; Varner, G.S.; /Hawaii U.; Va'vra, J.; Vavra, Jerry; /SLAC; ,

2012-07-30T23:59:59.000Z

396

Non-thermal Cosmic Backgrounds from Blazars: the contribution to the CMB, X-ray and gamma-ray Backgrounds  

E-Print Network [OSTI]

We present a new assessment of the contribution of Blazars to the extragalactic background radiation across the e.m. spectrum. Our calculations rely on deep Blazar radio counts that we derived combining several multifrequency surveys. The integrated Blazar emission yields a broad-band non-thermal background that in some parts of the e.m. spectrum dominates the extragalactic brightness. Blazars are the main point-like contributors to the CMB. Their integrated emission causes an apparent T increase of 5-50 muK in the 50-250 GHz range. The CMB fluctuation spectrum is sensibly contaminated at l>300, for a Poissonian source distribution, or at lower l values if spatial clustering is present. We estimate that well over 100,000 Blazars will produce a significant signal in the PLANCK CMB anisotropy maps. Because of the microwave-Xray flux correlation, these sources are expected to have flux > a few 10^{-15} erg/s in the soft X-ray band. Thus, a large fraction of the foreground sources in CMB anisotropy maps could be ...

Giommi, P; Cavazzuti, E; Perri, M; Pittori, C

2006-01-01T23:59:59.000Z

397

Fermi bubbles as a source of cosmic rays above 10^{15} eV  

E-Print Network [OSTI]

Fermi bubbles are giant gamma-ray structures extended north and south of the Galactic center with characteristic sizes of order of 10 kpc recently discovered by Fermi Large Area Telescope. Good correlation between radio and gamma-ray emission in the region covered by Fermi bubbles implies the presence of high-energy electrons in this region. Since it is relatively difficult for relativistic electrons of this energy to travel all the way from the Galactic sources toward Fermi bubbles one can assume that they accelerated in-situ. The corresponding acceleration mechanism should also affect the distribution of the relativistic protons in the Galaxy. Since protons have much larger lifetimes the effect may even be observed near the Earth. In our model we suggest that Fermi bubbles are created by acceleration of electrons on series of shocks born due to periodic star accretions by supermassive black hole Sgr A*. We propose that hadronic CR within the "knee" of the observed CR spectrum are produced by Galactic supern...

Chernyshov, D O; Dogiel, V A; Ko, C M

2014-01-01T23:59:59.000Z

398

THE INTERPLANETARY NETWORK SUPPLEMENT TO THE FERMI GBM CATALOG OF COSMIC GAMMA-RAY BURSTS  

SciTech Connect (OSTI)

We present Interplanetary Network (IPN) data for the gamma-ray bursts in the first Fermi Gamma-Ray Burst Monitor (GBM) catalog. Of the 491 bursts in that catalog, covering 2008 July 12 to 2010 July 11, 427 were observed by at least one other instrument in the nine-spacecraft IPN. Of the 427, the localizations of 149 could be improved by arrival time analysis (or {sup t}riangulation{sup )}. For any given burst observed by the GBM and one other distant spacecraft, triangulation gives an annulus of possible arrival directions whose half-width varies between about 0.'4 and 32 Degree-Sign , depending on the intensity, time history, and arrival direction of the burst, as well as the distance between the spacecraft. We find that the IPN localizations intersect the 1{sigma} GBM error circles in only 52% of the cases, if no systematic uncertainty is assumed for the latter. If a 6 Degree-Sign systematic uncertainty is assumed and added in quadrature, the two localization samples agree about 87% of the time, as would be expected. If we then multiply the resulting error radii by a factor of three, the two samples agree in slightly over 98% of the cases, providing a good estimate of the GBM 3{sigma} error radius. The IPN 3{sigma} error boxes have areas between about 1 arcmin{sup 2} and 110 deg{sup 2}, and are, on the average, a factor of 180 smaller than the corresponding GBM localizations. We identify two bursts in the IPN/GBM sample that did not appear in the GBM catalog. In one case, the GBM triggered on a terrestrial gamma flash, and in the other, its origin was given as ''uncertain''. We also discuss the sensitivity and calibration of the IPN.

Hurley, K. [University of California, Berkeley, Space Sciences Laboratory, 7 Gauss Way, Berkeley, CA 94720-7450 (United States); Pal'shin, V. D.; Aptekar, R. L.; Golenetskii, S. V.; Frederiks, D. D.; Mazets, E. P.; Svinkin, D. S. [Ioffe Physical Technical Institute, St. Petersburg 194021 (Russian Federation); Briggs, M. S.; Connaughton, V. [University of Alabama in Huntsville, NSSTC, 320 Sparkman Drive, Huntsville, AL 35805 (United States); Meegan, C. [Universities Space Research Association, NSSTC, 320 Sparkman Drive, Huntsville, AL 35805 (United States); Goldsten, J. [Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723 (United States); Boynton, W.; Fellows, C.; Harshman, K. [University of Arizona, Department of Planetary Sciences, Tucson, AZ 85721 (United States); Mitrofanov, I. G.; Golovin, D. V.; Kozyrev, A. S.; Litvak, M. L.; Sanin, A. B. [Space Research Institute, 84/32, Profsoyuznaya, Moscow 117997 (Russian Federation); Rau, A., E-mail: khurley@ssl.berkeley.edu [Max-Planck-Institut fuer extraterrestrische Physik, Giessenbachstrasse, Postfach 1312, D-85748 Garching (Germany); and others

2013-08-15T23:59:59.000Z

399

A Model for Most Luminous and Long Duration Cosmic Gamma Ray Bursts  

E-Print Network [OSTI]

We exploit the fact that General Theory of Relativity (GTR) predicts the existence of compact objects having surface gravitational redshift z_s burst rises dramatically with the value of z_c and can saturate to ~40%. This may explain a gamma ray burst of energy as high as ~5. 10**53 erg. By using the already existing detailed (Newtonian) calculations, it follows that the neutrino heating driven mass loss should be negligible, and the bulk Lorentz factor of the initial fireball could be ~1000. Most of the existing supernova calculations also show that it is extremely difficult to simulate the direct neutrino driven mass loss, and, the shock is not launched if the gravitational field becomes stronger. Since the gravitation potential well of the more compact NS is indded very deep, we do not expect additional baryonic mass ejection. So, without invoking any exotic physics (like strange stars) or overstretching any theory, we may explain most of the luminous GRBs in this simple model.

Abhas Mitra

1998-12-03T23:59:59.000Z

400

Tomographic-spectral approach for dark matter detection in the cross-correlation between cosmic shear and diffuse gamma-ray emission  

E-Print Network [OSTI]

We recently proposed to cross-correlate the diffuse gamma-ray emission with the gravitational lensing signal of cosmic shear. This represents a novel and promising strategy to search for annihilating or decaying dark matter (DM) candidates. In the present work, we demonstrate the potential of a tomographic-spectral approach: measuring the cross-correlation in separate bins of redshift and energy significantly improves the sensitivity to a DM signal. Indeed, the power of the proposed technique stems from the capability of simultaneously exploiting the different redshift scaling of astrophysical and DM components, their different energy spectra and their different angular shapes. The sensitivity to a particle DM signal is extremely promising even in the case the gamma-ray emission induced by DM is a subdominant component in the isotropic gamma-ray background. We quantify the prospects of detecting DM by cross-correlating the gamma-ray emission from the Fermi large area telescope (LAT) with the cosmic shear meas...

Camera, Stefano; Fornengo, Nicolao; Regis, Marco

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "int cosmic ray" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Observation of the Large Scale Cosmic-Ray Anisotropy at TeV Energies with the Milagro Detector  

E-Print Network [OSTI]

spirited, with both Peter and Allen were indispensable in the completion of this work. I would leave our showing possible deviation of the spectral index of the anisotropy signal from that of the nominal cosmic

California at Santa Cruz, University of

402

Biomarker Response to Galactic Cosmic Ray-Induced NOx and the Methane Greenhouse Effect in the Atmosphere of an Earthlike Planet Orbiting an M-Dwarf Star  

E-Print Network [OSTI]

Planets orbiting in the habitable zone (HZ) of M-Dwarf stars are subject to high levels of galactic cosmic rays (GCRs) which produce nitrogen oxides in earthlike atmospheres. We investigate to what extent this NOx may modify biomarker compounds such as ozone (O3) and nitrous oxide (N2O), as well as related compounds such as water (H2O) (essential for life) and methane (CH4) (which has both abiotic and biotic sources) . Our model results suggest that such signals are robust, changing in the M-star world atmospheric column by up to 20% due to the GCR NOx effects compared to an M-star run without GCR effects and can therefore survive at least the effects of galactic cosmic rays. We have not however investigated stellar cosmic rays here. CH4 levels are about 10 times higher than on the Earth related to a lowering in hydroxyl (OH) in response to changes in UV. The increase is less than reported in previous studies. This difference arose partly because we used different biogenic input. For example, we employed 23% lower CH4 fluxes compared to those studies. Unlike on the Earth, relatively modest changes in these fluxes can lead to larger changes in the concentrations of biomarker and related species on the M-star world. We calculate a CH4 greenhouse heating effect of up to 4K. O3 photochemistry in terms of the smog mechanism and the catalytic loss cycles on the M-star world differs considerably compared with the Earth.

John Lee Grenfell; Jean-Mathias Griessmeier; Beate Patzer; Heike Rauer; Antigona Segura; Anja Stadelmann; Barbara Stracke; Ruth Titz; Philip von Paris

2007-02-23T23:59:59.000Z

403

A New Method to Reconstruct the Energy and Determine the Composition of Cosmic Rays from the Measurement of Cherenkov Light and Particle Densities in Extensive Air Showers  

E-Print Network [OSTI]

A Monte-Carlo study to reconstruct energy and mass of cosmic rays with energies above 300 TeV using ground based measurements of the electromagnetic part of showers initiated in the atmosphere is presented. The shower properties determined with two detector arrays measuring the air Cherenkov light and the particle densities as realized at the HEGRA experiment are processed to determine the energy of the primary particle without the need of any hypothesis concerning its mass. The mass of the primary particle is reconstructed coarsely from the same observables in parallel to the energy determination.

A. Lindner

1998-01-15T23:59:59.000Z

404

The energy spectrum of cosmic rays above 10^15 eV as derived from air Cherenkov light measurements in Yakutsk  

E-Print Network [OSTI]

The Yakutsk array observes the Cherenkov light emitted by UHECR in atmosphere. Recently, an autonomous subarray is added consisting of photomultipliers to measure the showers in the knee region. Our aim is to analyze the combined data set in order to derive the cosmic ray spectrum in the energy range as wide as possible using the same technique. The advantage of the air Cherenkov light measurement is the model independent estimation of the EAS primary energy using the total light flux emitted in the atmosphere. A set of the light lateral distributions observed in the extended energy range is presented also.

A. A. Ivanov; S. P. Knurenko; I. Ye. Sleptsov

2003-05-05T23:59:59.000Z

405

European Cosmic Ray Symposium  

ScienceCinema (OSTI)

13me Symposium qui se droule du 27 au 31 juillet pour la premire fois au Cern. Brian Pattison ouvre la crmonie et donne la parole Dr.Ugland (qui reprsente le DG C.Rubbia excus) et d'autres intervenants

None

2011-04-25T23:59:59.000Z

406

Cosmic ray culprit revealed  

Science Journals Connector (OSTI)

......scientists were aiming for the outer solar sys- tem, for multi-spacecraft...planning process is to identify key technologies to be developed so that identified...are good prospects for better solar-cell technology for planetary missions as far......

Sue Bowler

2004-12-01T23:59:59.000Z

407

The IceCube Collaboration:contributions to the 30 th International Cosmic Ray Conference (ICRC 2007),  

E-Print Network [OSTI]

variety of sources (gamma-ray bursts, active galac- ticgalactic nuclei or gamma-ray bursts [1, 2]. Instead ofnuclei (AGN) and gamma-ray bursts (GRB) are potential

Ackermann, M.; IceCube Collaboration

2008-01-01T23:59:59.000Z

408

Herschel Survey of Galactic OH+, H2O+, and H3O+: Probing the Molecular Hydrogen Fraction and Cosmic-Ray Ionization Rate  

E-Print Network [OSTI]

In diffuse interstellar clouds the chemistry that leads to the formation of the oxygen bearing ions OH+, H2O+, and H3O+ begins with the ionization of atomic hydrogen by cosmic rays, and continues through subsequent hydrogen abstraction reactions involving H2. Given these reaction pathways, the observed abundances of these molecules are useful in constraining both the total cosmic-ray ionization rate of atomic hydrogen (zeta_H) and molecular hydrogen fraction, f(H2). We present observations targeting transitions of OH+, H2O+, and H3O+ made with the Herschel Space Observatory along 20 Galactic sight lines toward bright submillimeter continuum sources. Both OH+ and H2O+ are detected in absorption in multiple velocity components along every sight line, but H3O+ is only detected along 7 sight lines. From the molecular abundances we compute f(H2) in multiple distinct components along each line of sight, and find a Gaussian distribution with mean and standard deviation 0.042+-0.018. This confirms previous findings t...

Indriolo, Nick; Gerin, M; Schilke, P; Benz, A O; Winkel, B; Menten, K M; Chambers, E T; Black, John H; Bruderer, S; Falgarone, E; Godard, B; Goicoechea, J R; Gupta, H; Lis, D C; Ossenkopf, V; Persson, C M; Sonnentrucker, P; van der Tak, F F S; van Dishoeck, E F; Wolfire, Mark G; Wyrowski, F

2014-01-01T23:59:59.000Z

409

arXiv:0706.1212v2[astro-ph]12Jun2007 30th International Cosmic Ray Conference  

E-Print Network [OSTI]

. Cherenkov radiation is emitted in the water by the electrons and the muons as well as by electrons produced.ghia@lngs.infn.it Abstract: The building block of the surface detector of the Pierre Auger Observatory is a water Cherenkov the simulation chain, we compare the simulated signals produced by cosmic muons at various zenith angles

410

Neutrino and Cosmic-Ray Emission and Cumulative Background from Radiatively Inefficient Accretion Flows in Low-Luminosity Active Galactic Nuclei  

E-Print Network [OSTI]

We study high-energy neutrino and cosmic-ray (CR) emission from the cores of low-luminosity active galactic nuclei (LLAGN). In LLAGN, the thermalization of particles is expected to be incomplete in radiatively inefficient accretion flows (RIAFs), allowing the existence of non-thermal particles. In this work, assuming stochastic particle acceleration due to turbulence in RIAFs, we solve the Fokker-Planck equation and calculate spectra of escaping neutrinos and CRs. The RIAF in LLAGN can emit CR protons with $\\gtrsim10$ PeV energies and TeV-PeV neutrinos generated via $pp$ and/or $p\\gamma$ reactions. We find that, if $\\sim1$% of the accretion luminosity is carried away by non-thermal ions, the diffuse neutrino intensity from the cores of LLAGN may be as high as $E_\

Shigeo S. Kimura; Kohta Murase; Kenji Toma

2014-11-13T23:59:59.000Z

411

Reply to 'Influence of cosmic ray variability on the monsoon rainfall and temperature': a false-positive in the field of solar-terrestrial research  

E-Print Network [OSTI]

A litany of research has been published claiming strong solar influences on the Earth's weather and climate. Much of this work includes documented errors and false-positives, yet is still frequently used to substantiate arguments of global warming denial. This manuscript reports on a recent study by Badruddin & Aslam (2014), hereafter BA14, which claimed a highly significant ($p=1.4\\times10^{-5}$) relationship between extremes in the intensity of the Indian monsoon and the cosmic ray flux. They further speculated that the relationship they observed may apply across the entire tropical and sub-tropical belt, and be of global importance. However, their statistical analysis---and consequently their conclusions---were wrong. Specifically, their error resulted from an assumption that their data's underlying distribution was Gaussian. But, as demonstrated in this work, their data closely follow an ergodic chaotic distribution biased towards extreme values. From a probability density function, calculated using a...

Laken, Benjamin A

2015-01-01T23:59:59.000Z

412

On the possibility to discriminate the mass of the primary cosmic ray using the muon arrival times from extensive air showers: Application for Pierre Auger Observatory  

SciTech Connect (OSTI)

In this paper we study the possibility to discriminate the mass of the primary cosmic ray by observing the muon arrival times in ground detectors. We analyzed extensive air showers (EAS) induced by proton and iron nuclei with the same energy 8 Multiplication-Sign 10{sup 17} eV simulated with CORSIKA, and analyzed the muon arrival times at ground measured by the infill array detectors of the Pierre Auger Observatory (PAO). From the arrival times of the core and of the muons the atmospheric depth of muon generation locus is evaluated. The results suggest a potential mass discrimination on the basis of muon arrival times and of the reconstructed atmospheric depth of muon production. An analysis of a larger set of CORSIKA simulations carried out for primary energies above 10{sup 18} eV is in progress.

Arsene, N.; Rebel, H.; Sima, O. [Institute of Space Science (ISS), Bucharest-Magurele, P.O. Box MG-23 (Romania) and Physics Department, University of Bucharest, Bucharest-Magurele (Romania); Karlsruhe Institute of Technology, Karlsruhe (Germany); Physics Department, University of Bucharest, Bucharest-Magurele (Romania)

2012-11-20T23:59:59.000Z

413

GEANT4 Simulation of a Scintillating-Fibre Tracker for the Cosmic-ray Muon Tomography of Legacy Nuclear Waste Containers  

E-Print Network [OSTI]

Cosmic-ray muons are highly penetrative charged particles that are observed at sea level with a flux of approximately one per square centimetre per minute. They interact with matter primarily through Coulomb scattering, which is exploited in the field of muon tomography to image shielded objects in a wide range of applications. In this paper, simulation studies are presented that assess the feasibility of a scintillating-fibre tracker system for use in the identification and characterisation of nuclear materials stored within industrial legacy waste containers. A system consisting of a pair of tracking modules above and a pair below the volume to be assayed is simulated within the GEANT4 framework using a range of potential fibre pitches and module separations. Each module comprises two orthogonal planes of fibres that allow the reconstruction of the initial and Coulomb-scattered muon trajectories. A likelihood-based image reconstruction algorithm has been developed that allows the container content to be det...

Clarkson, Anthony; Hoek, Matthias; Ireland, David G; Johnstone, Russell; Kaiser, Ralf; Keri, Tibor; Lumsden, Scott; Mahon, David F; McKinnon, Bryan; Murray, Morgan; Nutbeam-Tuffs, Sian; Shearer, Craig; Staines, Cassie; Yang, Guangliang; Zimmerman, Colin

2013-01-01T23:59:59.000Z

414

The Design and Performance of a Scintillating-Fibre Tracker for the Cosmic-ray Muon Tomography of Legacy Nuclear Waste Containers  

E-Print Network [OSTI]

Tomographic imaging techniques using the Coulomb scattering of cosmic-ray muons are increasingly being exploited for the non-destructive assay of shielded containers in a wide range of applications. One such application is the characterisation of legacy nuclear waste materials stored within industrial containers. The design, assembly and performance of a prototype muon tomography system developed for this purpose are detailed in this work. This muon tracker comprises four detection modules, each containing orthogonal layers of Saint-Gobain BCF-10 2mm-pitch plastic scintillating fibres. Identification of the two struck fibres per module allows the reconstruction of the incoming and Coulomb-scattered muon trajectories. These allow the container content, with respect to the atomic number Z of the scattering material, to be determined through reconstruction of the scattering location and magnitude. On each detection layer, the light emitted by the fibre is detected by a single Hamamatsu H8500 MAPMT with two fibre...

Clarkson, Anthony; Hoek, Matthias; Ireland, David G; Johnstone, Russell; Kaiser, Ralf; Keri, Tibor; Lumsden, Scott; Mahon, David F; McKinnon, Bryan; Murray, Morgan; Nutbeam-Tuffs, Sian; Shearer, Craig; Staines, Cassie; Yang, Guangliang; Zimmerman, Colin

2013-01-01T23:59:59.000Z

415

Simulating cosmic rays in clusters of galaxies III. Non-thermal scaling relations and comparison to observations  

Science Journals Connector (OSTI)

......Orlandini 2007a,b; Rossetti Molendi 2007). Observational efforts, such as the future hard X-ray missions NuSTAR and Simbol-X, have to be undertaken to unambiguously detect the spectral and spatial characteristics of the hard X-ray excess emission......

Christoph Pfrommer

2008-04-11T23:59:59.000Z

416

Simulating cosmic rays in clusters of galaxies II. A unified scheme for radio haloes and relics with predictions of the -ray emission  

Science Journals Connector (OSTI)

......low-frequency radio arrays (GMRT,1 LOFAR,2 MWA,3 LWA4), the future hard X-ray satellite missions NuSTAR 5 and Simbol-X, and gamma-ray instruments (the GLAST 6 satellite and imaging atmospheric cerenkov telescopes H.E.S.S.,7 MAGIC......

Christoph Pfrommer; Torsten A. Enlin; Volker Springel

2008-04-11T23:59:59.000Z

417

CONTRIBUTION OF GAMMA-RAY-LOUD RADIO GALAXIES' CORE EMISSIONS TO THE COSMIC MeV AND GeV GAMMA-RAY BACKGROUND RADIATION  

SciTech Connect (OSTI)

The Fermi gamma-ray satellite has recently detected gamma-ray emissions from radio galaxy cores. From these samples, we first examine the correlation between the luminosities at 5 GHz, L{sub 5GHz}, and at 0.1-10 GeV, L{sub {gamma}}, of gamma-ray-loud radio galaxies. We find that the correlation is significant with L{sub {gamma}}{proportional_to}L{sup 1.16}{sub 5GHz} based on a partial correlation analysis. Using this correlation and the radio luminosity function (RLF) of radio galaxies, we explore the contribution of gamma-ray-loud radio galaxies to the unresolved extragalactic gamma-ray background (EGRB). The gamma-ray luminosity function is obtained by normalizing the RLF to reproduce the source-count distribution of the Fermi gamma-ray-loud radio galaxies. We find that gamma-ray-loud radio galaxies can explain {approx}25% of the unresolved Fermi EGRB flux above 100 MeV and will also make a significant contribution to the EGRB in the 1-30 MeV energy band. Since blazars explain 22% of the EGRB above 100 MeV, radio-loud active galactic nucleus populations explain {approx}47% of the unresolved EGRB. We further make an interpretation on the origin of the EGRB. The observed EGRB spectrum at 0.2-100 GeV does not show an absorption signature by the extragalactic background light. Thus, the dominant population of the origin of EGRB at very high energy (>30 GeV) might be either nearby gamma-ray-emitting sources or sources with very hard gamma-ray spectra.

Inoue, Yoshiyuki, E-mail: yinoue@kusastro.kyoto-u.ac.jp [Department of Astronomy, Kyoto University, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 (Japan)

2011-05-20T23:59:59.000Z

418

Proceedings of ICRC 2001: 2088 c Copernicus Gesellschaft 2001 Numerical studies of cosmic ray injection and acceleration  

E-Print Network [OSTI]

thermal particles are injected into the CRs, roughly independent of Mach numbers. Due to severe ray injection and acceleration H. Kang1 , T. W. Jones2 , and U. D. J. Gieseler3 1 Pusan National hereafter) injection model into the combined gas dynamics and CR diffusion- convection code. Our hydro

Gieseler, Udo D. J.

419

arXiv:0706.1491v1[astro-ph]11Jun2007 30TH INTERNATIONAL COSMIC RAY CONFERENCE  

E-Print Network [OSTI]

¨ue, Mendoza, Argentina C.Bleve@leeds.ac.uk Abstract: The rate of events measured with the surface detector The surface detector (SD) of the Auger Southern Observatory, located in Malarg¨ue, Argentina, is de- signed for the detection of ultra high energy cos- mic rays through the measurement of the signal in- duced by the shower

420

Cross-calibration of the Transition Radiation Detector of AMS-02 for an Energy Measurement of Cosmic-Ray Ions  

E-Print Network [OSTI]

Since May 2011 the AMS-02 experiment is installed on the International Space Station and is observing cosmic radiation. It consists of several state-of-the-art sub-detectors, which redundantly measure charge and energy of traversing particles. Due to the long exposure time of AMS-02 of many years the measurement of momentum for protons and ions is limited systematically by the spatial resolution and magnetic field strength of the silicon tracker. The maximum detectable rigidity for protons is about 1.8~TV, for helium about 3.6~TV. We investigate the possibility to extend the range of the energy measurement for heavy nuclei ($Z\\geq2$) with the transition radiation detector (TRD). The response function of the TRD shows a steep increase in signal from the level of ionization at a Lorentz factor $\\gamma$ of about 500 to $\\gamma\\approx20000$, where the transition radiation signal saturates. For heavy ions the signal fluctuations in the TRD are sufficiently small to allow an energy measurement with the TRD beyond t...

Obermeier, Andreas

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "int cosmic ray" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

A technique for verifying the input response function of neutron time-of-flight scintillation detectors using cosmic rays  

SciTech Connect (OSTI)

An accurate interpretation of DD or DT fusion neutron time-of-flight (nTOF) signals from current mode detectors employed at the Z-facility at Sandia National Laboratories requires that the instrument response functions (IRFs) be deconvolved from the measured nTOF signals. A calibration facility that produces detectable sub-ns radiation pulses is typically used to measure the IRF of such detectors. This work, however, reports on a simple method that utilizes cosmic radiation to measure the IRF of nTOF detectors, operated in pulse-counting mode. The characterizing metrics reported here are the throughput delay and full-width-at-half-maximum. This simple approach yields consistent IRF results with the same detectors calibrated in 2007 at a LINAC bremsstrahlung accelerator (Idaho State University). In particular, the IRF metrics from these two approaches and their dependence on the photomultipliers bias agree to within a few per cent. This information may thus be used to verify if the IRF for a given nTOF detector employed at Z has changed since its original current-mode calibration and warrants re-measurement.

Bonura, M. A.; Cooper, G. W.; Nelson, A. J.; Styron, J. D. [Department of Chemical and Nuclear Engineering, University of New Mexico, Albuquerque, New Mexico 87131 (United States); Ruiz, C. L., E-mail: clruiz@sandia.gov; Fehl, D. L.; Chandler, G.; Hahn, K. D.; Torres, J. A. [Sandia National Laboratories, Diagnostics and Target Physics, Albuquerque, New Mexico 87111 (United States)

2014-11-15T23:59:59.000Z

422

Comment on "Violation of the Greisen-Zatsepin-Kuzmin Cutoff A Tempest in a (Magnetic) Teapot? Why Cosmic Ray Energies above $10^{20}$ eV May Not Require New Physics"  

E-Print Network [OSTI]

In a recent letter [1] with the same title, Farrar and Piran offered an explanation for the near isotropy of the arrival directions [2] of ultrahigh energy cosmic rays (UHECRs) and the apparent absence [3] of the so called `GZK cutoff' in their spectrum around $10^{20}$ eV due to pion photoproduction on the cosmic background radiation (CMB) that was predicted independently by Greisen [4] and by Zatsepin and Kuz'min [5]. They suggested that the extragalactic magnetic fields near the Milky Way are strong enough to deflect and isotropise the arrival directions of the UHECRs from a few nearby sources for which their travel time to Earth is shorter than their attenuation time by pion photoproduction on the CMB. They also estimated that this allows active galactic nuclei (AGNs) or gamma ray bursts (GRBs) to be the source of the UHECRs. However, these suggestions are inconsistent with various observations

Dar, Arnon

2000-01-01T23:59:59.000Z

423

Comment on ``Violation of the Greisen-Zatsepin-Kuzmin Cutoff: A Tempest in a (Magnetic) Teapot? Why Cosmic Ray Energies above $10^{20}$ eV May Not Require New Physics''  

E-Print Network [OSTI]

In a recent letter [1] with the same title, Farrar and Piran offered an explanation for the near isotropy of the arrival directions [2] of ultrahigh energy cosmic rays (UHECRs) and the apparent absence [3] of the so called `GZK cutoff' in their spectrum around $10^{20}$ eV due to pion photoproduction on the cosmic background radiation (CMB) that was predicted independently by Greisen [4] and by Zatsepin and Kuz'min [5]. They suggested that the extragalactic magnetic fields near the Milky Way are strong enough to deflect and isotropise the arrival directions of the UHECRs from a few nearby sources for which their travel time to Earth is shorter than their attenuation time by pion photoproduction on the CMB. They also estimated that this allows active galactic nuclei (AGNs) or gamma ray bursts (GRBs) to be the source of the UHECRs. However, these suggestions are inconsistent with various observations

Arnon Dar

2000-06-01T23:59:59.000Z

424

Simulating cosmic rays in clusters of galaxies II. A unified scheme for radio haloes and relics with predictions of the -ray emission  

Science Journals Connector (OSTI)

......synchrotron emission between 15 MHz and 1.4 GHz, (2) non-thermal...at radio frequencies (nu 10 MHz) as well as at hard X-ray...the thermal core causing the plasma beta parameter to decrease by...these sources within the cluster atmosphere causing some foreground objects......

Christoph Pfrommer; Torsten A. Enlin; Volker Springel

2008-04-11T23:59:59.000Z

425

Searches for Large-Scale Anisotropy in the Arrival Directions of Cosmic Rays Detected above Energy of $10^{19}$ eV at the Pierre Auger Observatory and the Telescope Array  

SciTech Connect (OSTI)

Spherical harmonic moments are well-suited for capturing anisotropy at any scale in the flux of cosmic rays. An unambiguous measurement of the full set of spherical harmonic coefficients requires full-sky coverage. This can be achieved by combining data from observatories located in both the northern and southern hemispheres. To this end, a joint analysis using data recorded at the Telescope Array and the Pierre Auger Observatory above 1019 eV is presented in this work. The resulting multipolar expansion of the flux of cosmic rays allows us to perform a series of anisotropy searches, and in particular to report on the angular power spectrum of cosmic rays above 1019 eV. No significant deviation from isotropic expectations is found throughout the analyses performed. Upper limits on the amplitudes of the dipole and quadrupole moments are derived as a function of the direction in the sky, varying between 7% and 13% for the dipole and between 7% and 10% for a symmetric quadrupole.

Aab, Alexander; et al,

2014-10-07T23:59:59.000Z

426

Systematic uncertainties on the cosmic-ray transport parameters: Is it possible to reconcile B/C data with delta = 1/3 or delta = 1/2?  

E-Print Network [OSTI]

The B/C ratio is used in cosmic-ray physics to constrain the transport parameters. However, from the same set of data, the various published values show a puzzling large scatter of these parameters. We investigate the impact of using different inputs (gas density and hydrogen fraction in the Galactic disc, source spectral shape, low-energy dependence of the diffusion coefficient, and nuclear fragmentation cross-sections) on the best-fit values of the transport parameters. We quantify the systematics produced when varying these inputs, and compare them to statistical uncertainties. We discuss the consequences for the slope of the diffusion coefficient delta. The analysis relies on the propagation code USINE interfaced with the Minuit minimisation routines. We find the typical systematic uncertainties to be larger than the statistical ones. The several published values of delta (from 0.3 to 0.8) can be recovered when varying the low-energy shape of the diffusion coefficient and the convective wind strength. Mod...

Maurin, D; Derome, L

2010-01-01T23:59:59.000Z

427

Observation of the anisotropy of 10TeV primary cosmic ray nuclei flux with the Super-Kamiokande-I detector  

Science Journals Connector (OSTI)

The relative sidereal variation in the arrival direction of primary cosmic ray nuclei of median energy 10TeV was measured using downward, through-going muons detected with the Super-Kamiokande-I detector. The projection of the anisotropy map onto the right ascension axis has a first harmonic amplitude of (6.640.98??stat0.55??syst)10-4 and a phase at maximum at (33.28.2??stat5.1??syst) right ascension. A sky map in equatorial coordinates indicates an excess region in the constellation of Taurus and a deficit region toward Virgo. The excess region is centered at (?T,?T)=(757,-59) with a half-opening angle ?T=(397); the excess flux is (0.1040.020)% above the isotropic expectation. The corresponding parameters for the deficit region are (?V,?V)=(2057,510), ?V=(547), and (-0.0940.014)%. The data do not allow us to rule out a pure dipole form for the anisotropy (allowed at 13% confidence level); they are better described by the excess and deficit cones described above. We explored the implications under the assumption that the true anisotropy is not distorted too much by the analysis filter so that it is well-described by the observed excess and deficit cones.

G. Guillian et al. (Super-Kamiokande Collaboration)

2007-03-23T23:59:59.000Z

428

CORRELATIONS OF THE ARRIVAL DIRECTIONS OF ULTRA-HIGH ENERGY COSMIC RAYS WITH EXTRAGALACTIC OBJECTS AS OBSERVED BY THE TELESCOPE ARRAY EXPERIMENT  

SciTech Connect (OSTI)

We search for correlations between the positions of extragalactic objects and the arrival directions of ultra-high energy cosmic rays (UHECRs) with primary energy E ? 40 EeV as observed by the surface detector array of the Telescope Array (TA) experiment during the first 40 months of operation. We examine several public astronomical object catalogs, including the Veron-Cetty and Veron catalog of active galactic nuclei. We count the number of TA events correlated with objects in each catalog as a function of three parameters: the maximum angular separation between a TA event and an object, the minimum energy of the events, and the maximum redshift of the objects. We determine the combination of these parameters that maximizes the correlations, and we calculate the probability of having the same levels of correlations from an isotropic distribution of UHECR arrival directions. No statistically significant correlations are found when penalties for scanning over the above parameters and for searching in several catalogs are taken into account.

Abu-Zayyad, T.; Allen, M.; Anderson, R.; Barcikowski, E.; Belz, J. W.; Bergman, D. R.; Blake, S. A.; Cady, R.; Hanlon, W. [High Energy Astrophysics Institute and Department of Physics and Astronomy, University of Utah, Salt Lake City, UT (United States); Aida, R. [Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Kofu, Yamanashi (Japan); Azuma, R.; Fukuda, T. [Graduate School of Science and Engineering, Tokyo Institute of Technology, Meguro, Tokyo (Japan); Cheon, B. G.; Cho, E. J. [Department of Physics and The Research Institute of Natural Science, Hanyang University, Seongdong-gu, Seoul (Korea, Republic of); Chiba, J. [Department of Physics, Tokyo University of Science, Noda, Chiba (Japan); Chikawa, M. [Department of Physics, Kinki University, Higashi Osaka, Osaka (Japan); Cho, W. R. [Department of Physics, Yonsei University, Seodaemun-gu, Seoul (Korea, Republic of); Fujii, H. [Institute of Particle and Nuclear Studies, KEK, Tsukuba, Ibaraki (Japan); Fujii, T. [Graduate School of Science, Osaka City University, Osaka (Japan); Fukushima, M. [Institute for Cosmic Ray Research, University of Tokyo, Kashiwa, Chiba (Japan); and others

2013-11-10T23:59:59.000Z

429

GEANT4 Simulation of a Scintillating-Fibre Tracker for the Cosmic-ray Muon Tomography of Legacy Nuclear Waste Containers  

E-Print Network [OSTI]

Cosmic-ray muons are highly penetrative charged particles that are observed at sea level with a flux of approximately one per square centimetre per minute. They interact with matter primarily through Coulomb scattering, which is exploited in the field of muon tomography to image shielded objects in a wide range of applications. In this paper, simulation studies are presented that assess the feasibility of a scintillating-fibre tracker system for use in the identification and characterisation of nuclear materials stored within industrial legacy waste containers. A system consisting of a pair of tracking modules above and a pair below the volume to be assayed is simulated within the GEANT4 framework using a range of potential fibre pitches and module separations. Each module comprises two orthogonal planes of fibres that allow the reconstruction of the initial and Coulomb-scattered muon trajectories. A likelihood-based image reconstruction algorithm has been developed that allows the container content to be determined with respect to the atomic number Z of the scattering material. Images reconstructed from this simulation are presented for a range of anticipated scenarios that highlight the expected image resolution and the potential of this system for the identification of high-Z materials within a shielded, concrete-filled container. First results from a constructed prototype system are presented in comparison with those from a detailed simulation. Excellent agreement between experimental data and simulation is observed showing clear discrimination between the different materials assayed throughout.

Anthony Clarkson; David J. Hamilton; Matthias Hoek; David G. Ireland; Russell Johnstone; Ralf Kaiser; Tibor Keri; Scott Lumsden; David F. Mahon; Bryan McKinnon; Morgan Murray; Sian Nutbeam-Tuffs; Craig Shearer; Cassie Staines; Guangliang Yang; Colin Zimmerman

2013-09-13T23:59:59.000Z

430

A Method for energy estimation and mass composition determination of primary cosmic rays at Chacaltaya observation level based on atmospheric Cerenkov light technique  

E-Print Network [OSTI]

A new method for energy and mass composition estimation of primary cosmic ray radiation based on atmospheric Cerenkov light flux in extensive air showers (EAS) analysis is proposed. The Cerenkov light flux in EAS initiated by primary protons and iron nuclei is simulated with CORSIKA 5.62 code for Chacaltaya observation level (536 g/cm2) in the energy range 10 TeV - 10 PeV. An adequate model, approximation of lateral distribution of Cerenkov light in showers is obtained. Using the proposed model and solution of overdetermined system of nonlinear equations based on Gauss Newton method with autoregularization, two different array detector arrangements are compared. The detector response for the detector sets is simulated. The accuracies in energy and shower axis determination are studied and the corresponding selection criteria are proposed. An approximation with nonlinear fit is obtained and the energy dependence of the proposed model function parameters is studied. The approximation of model parameters as function of the primary energy is carried out. This permits, taking into account the properties of the proposed method and model, to distinguish proton primaries from iron primaries. The detector response for the detector sets is simulated and the accuracies in energy determination are calculated. Moreover the accuracies in shower axis determination are studied and criteria in shower axis position estimation are proposed.

S. Mavrodiev; A. Mishev; J. Stamenov

2003-10-22T23:59:59.000Z

431

Gamma Ray Bursts  

E-Print Network [OSTI]

Olson. Observations of gamma-ray bursts of cosmic origin. E. Lingenfelter. Gamma-ray bursts. Annual Review of652-654. Waxman, Eli. Gamma-ray-burst afterglow: supporting

Stahl, Bennett

2014-01-01T23:59:59.000Z

432

E-Print Network 3.0 - accelerated cosmic expansion Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Groningen Collection: Physics 6 Cosmic Ray Acceleration beyond the Knee up to the Ankle in the Galactic Wind Halo Summary: Cosmic Ray Acceleration beyond the Knee up to the...

433

Cosmic Structures  

Science Journals Connector (OSTI)

In this first chapter, the cosmic players (objects) are introduced superficially, whose detailed properties will then entertain us to the end of the book. The play starts in front of our doors, with the Solar Sys...

Professor Dr. Wolfgang Kundt

2001-01-01T23:59:59.000Z

434

Origin of the High Energy Cosmic Neutrino Background  

Science Journals Connector (OSTI)

The diffuse background of very high energy extraterrestrial neutrinos recently discovered with IceCube is compatible with that expected from cosmic ray interactions in the Galactic interstellar medium plus that expected from hadronic interactions near the source and in the intergalactic medium of the cosmic rays which have been accelerated by the jets that produce gamma ray bursts.

Shlomo Dado and Arnon Dar

2014-11-07T23:59:59.000Z

435

Smoothing of the cosmic background radiation by multiple gravitational scattering  

Science Journals Connector (OSTI)

We investigated the smoothing of the cosmic background radiation (CBR) ... rays increases exponentially through multiple scatterings. This exponential growth occurs if the distance is smaller...

Junichiro Making

1994-01-01T23:59:59.000Z

436

NERSC Helps Discover Cosmic Transients - NERSC Science News June...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Lab) to expose relatively rare and fleeting cosmic events, like supernovae and gamma ray bursts. In fact, during the commissioning phase alone, the survey has already uncovered...

437

Observation of the anisotropy of 10 TeV primary cosmic ray nuclei flux with the Super-Kamiokande-I detector  

SciTech Connect (OSTI)

The relative sidereal variation in the arrival direction of primary cosmic ray nuclei of median energy 10 TeV was measured using downward, through-going muons detected with the Super-Kamiokande-I detector. The projection of the anisotropy map onto the right ascension axis has a first harmonic amplitude of (6.64{+-}0.98 stat{+-}0.55 syst)x10{sup -4} and a phase at maximum at (33.2 deg. {+-}8.2 deg. stat{+-}5.1 deg. syst) right ascension. A sky map in equatorial coordinates indicates an excess region in the constellation of Taurus and a deficit region toward Virgo. The excess region is centered at ({alpha}{sub T},{delta}{sub T})=(75 deg. {+-}7 deg., -5 deg. {+-}9 deg.) with a half-opening angle {chi}{sub T}=(39{+-}7) deg.; the excess flux is (0.104{+-}0.020)% above the isotropic expectation. The corresponding parameters for the deficit region are ({alpha}{sub V},{delta}{sub V})=(205 deg. {+-}7 deg., 5 deg. {+-}10 deg.), {chi}{sub V}=(54{+-}7) deg., and (-0.094{+-}0.014)%. The data do not allow us to rule out a pure dipole form for the anisotropy (allowed at 13% confidence level); they are better described by the excess and deficit cones described above. We explored the implications under the assumption that the true anisotropy is not distorted too much by the analysis filter so that it is well-described by the observed excess and deficit cones.

Guillian, G.; Kibayashi, A.; Learned, J. G.; Matsuno, S. [Department of Physics and Astronomy, University of Hawaii, Honolulu, Hawaii 96822 (United States); Hosaka, J.; Ishihara, K.; Kameda, J.; Koshio, Y.; Minamino, A.; Mitsuda, C.; Miura, M.; Moriyama, S.; Nakahata, M.; Namba, T.; Obayashi, Y.; Ogawa, H.; Shiozawa, M.; Suzuki, Y.; Takeda, A.; Takeuchi, Y. [Kamioka Observatory, Institute for Cosmic Ray Research, University of Tokyo, Hida, Gifu, 506-1205 (Japan)] (and others)

2007-03-15T23:59:59.000Z

438

Int J Computer Vision 3 (1989) 181-208 1 Int J Computer Vision 3 (1989) 181-208 2  

E-Print Network [OSTI]

Int J Computer Vision 3 (1989) 181-208 1 #12;Int J Computer Vision 3 (1989) 181-208 2 #12;Int J Computer Vision 3 (1989) 181-208 3 #12;Int J Computer Vision 3 (1989) 181-208 4 #12;Int J Computer Vision 3 (1989) 181-208 5 #12;Int J Computer Vision 3 (1989) 181-208 6 #12;Int J Computer Vision 3 (1989) 181

Murray, David

439

Cosmical Electrodynamics  

Science Journals Connector (OSTI)

A review is given of the development in the field of cosmical electrodynamics. It is mentioned that the great interest in thermonuclear research has produced a considerable progress in plasma physics. This is of astrophysical interest because it is now possible to check the theories of a plasma by experiment.

H. Alfvn

1960-01-01T23:59:59.000Z

440

Compton Recoil Electron Tracking With the TIGRE Gamma-Ray Balloon Experiment  

E-Print Network [OSTI]

AGNs), pulsars, gamma-ray bursts, cosmic ray interactionssensitive to cosmic gamma-ray bursts in the energy range ofGalactic center, a single gamma-ray burst which occurred 10

Kamiya, Kaoru

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "int cosmic ray" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

On the trailof COSMIC BULLETS  

E-Print Network [OSTI]

|volume04|issue08/09|oct/nov07 17 Argentina's Pampa Amarilla is a rather remote place, a dry plain, an unusually powerful cosmic ray strikes the Earth's atmosphere with almost as much energy as a bullet. Fortunately, such a projectile is no danger to human life. Entering the atmosphere, it loses energy

442

A cosmic ray hodoscope system  

E-Print Network [OSTI]

the central control circuits, which Pig. 20. An ovexe11 view oX the hodoscope system. 4 , 4 4 4 J 4 4 4 4 4t 4 4I 4 . 'i~+44 4 4 4 ~ 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 34 are on the thirteenth board... the central control circuits, which Pig. 20. An ovexe11 view oX the hodoscope system. 4 , 4 4 4 J 4 4 4 4 4t 4 4I 4 . 'i~+44 4 4 4 ~ 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 34 are on the thirteenth board...

Cantrell, Wallace Gene

2012-06-07T23:59:59.000Z

443

Mechanism for Cosmic Ray Modulation  

Science Journals Connector (OSTI)

... change much as neither solar wind speed nor solar wind density6 does as required, making solar wind energy density more or less invariant over a long period. Furthermore, if the boundary is ...

TITUS MATHEWS; JOHN QUENBY; JOHN SEAR

1971-01-22T23:59:59.000Z

444

HAWC ?-Ray Observatory  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

(HAWC) Gamma Ray Observatory formally began operations. HAWC is designed to study the origin of very high-energy cosmic rays and observe the most energetic objects in the known...

445

Cosmic Particle Acceleration: Basic Issues  

E-Print Network [OSTI]

Cosmic-rays are ubiquitous, but their origins are surprisingly difficult to understand. A review is presented of some of the basic issues common to cosmic particle accelerators and arguments leading to the likely importance of diffusive shock acceleration as a general explanation. The basic theory of diffusive shock acceleration is outlined, followed by a discussion of some of the key issues that still prevent us from a full understanding of its outcomes. Some recent insights are mentioned at the end that may help direct ultimate resolution of our uncertainties.

T. W. Jones

2000-12-22T23:59:59.000Z

446

HD/H2 as a probe of the roles of gas, dust, light, metallicity and cosmic rays in promoting the growth of molecular hydrogen in the diffuse interstellar medium  

E-Print Network [OSTI]

We modelled recent observations of UV absorption of HD and \\HH\\ in the Milky Way and toward damped/sub-damped Lyman alpha systems at z=0.18 and z $>$ 1.7. N(HD)/N(\\HH) ratios reflect the separate self-shieldings of HD and \\HH\\ and the coupling introduced by deuteration chemistry. Locally, observations are explained by diffuse molecular gas with $ 16 \\pccc \\la$ n(H) $\\la 128 \\pccc $ if the cosmic-ray ionization rate per H-nucleus \\zetaH $= 2\\times 10^{-16}\\ps$ as inferred from \\H3\\p\\ and OH\\p. The dominant influence on N(HD)/N(\\HH) is the cosmic-ray ionization rate with a much weaker downward dependence on n(H) at Solar metallicity, but dust-extinction can drive N(HD) higher as with N(\\HH). At z $>$ 1.7, N(HD) is comparable to the Galaxy but with 10x smaller N(\\HH) and somewhat smaller N(\\HH)/N(H I). Comparison of our Galaxy and the Magellanic Clouds shows that smaller \\HH/H is expected at sub-Solar metallicity and we show by modelling that HD/\\HH\\ increases with density at low metallicity, opposite to the Mil...

Liszt, H S

2014-01-01T23:59:59.000Z

447

E-Print Network 3.0 - alternative high-z cosmic Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

5 > >> 1 StructureStructure in the Universein the Universe Summary: -rays Gaseous Cosmic Web - Baryonic gas traces the Cosmic Web: Ly forest neutral hydrogen gas, mostly at high...

448

INTERACTING COSMIC RAYS WITH MOLECULAR CLOUDS: A BREMSSTRAHLUNG ORIGIN OF DIFFUSE HIGH-ENERGY EMISSION FROM THE INNER 2 Degree-Sign Multiplication-Sign 1 Degree-Sign OF THE GALACTIC CENTER  

SciTech Connect (OSTI)

The high-energy activity in the inner few degrees of the Galactic center is traced by diffuse radio, X-ray, and {gamma}-ray emission. The physical relationship between different components of diffuse gas emitting at multiple wavelengths is a focus of this work. We first present radio continuum observations using the Green Bank Telescope and model the nonthermal spectrum in terms of a broken power-law distribution of {approx}GeV electrons emitting synchrotron radiation. We show that the emission detected by Fermi is primarily due to nonthermal bremsstrahlung produced by the population of synchrotron emitting electrons in the GeV energy range interacting with neutral gas. The extrapolation of the electron population measured from radio data to low and high energies can also explain the origin of Fe I 6.4 keV line and diffuse TeV emission, as observed with Suzaku, XMM-Newton, Chandra, and the H.E.S.S. observatories. The inferred physical quantities from modeling multiwavelength emission in the context of bremsstrahlung emission from the inner {approx}300 Multiplication-Sign 120 pc of the Galactic center are constrained to have the cosmic-ray ionization rate {approx}1-10 Multiplication-Sign 10{sup -15} s{sup -1}, molecular gas heating rate elevating the gas temperature to 75-200 K, fractional ionization of molecular gas 10{sup -6}-10{sup -5}, large-scale magnetic field 10-20 {mu}G, the density of diffuse and dense molecular gas {approx}100 and {approx}10{sup 3} cm{sup -3} over 300 pc and 50 pc path lengths, and the variability of Fe I K{alpha} 6.4 keV line emission on yearly timescales. Important implications of our study are that GeV electrons emitting in radio can explain the GeV {gamma}-rays detected by Fermi and that the cosmic-ray irradiation model, like the model of the X-ray irradiation triggered by past activity of Sgr A*, can also explain the origin of the variable 6.4 keV emission from Galactic center molecular clouds.

Yusef-Zadeh, F.; Roberts, D. A.; Royster, M. [Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208 (United States)] [Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208 (United States); Hewitt, J. W. [Code 662, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)] [Code 662, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Wardle, M. [Department of Physics and Astronomy, and Research Center for Astronomy, Astrophysics and Astrophotonics, Macquarie University, Sydney, NSW 2109 (Australia)] [Department of Physics and Astronomy, and Research Center for Astronomy, Astrophysics and Astrophotonics, Macquarie University, Sydney, NSW 2109 (Australia); Tatischeff, V. [Center de Spectrometrie Nucleaire et de Spectrometrie de Massse, IN2P3/CNRS and Univ. Paris-Sud, F-91405 Orsay Campus (France)] [Center de Spectrometrie Nucleaire et de Spectrometrie de Massse, IN2P3/CNRS and Univ. Paris-Sud, F-91405 Orsay Campus (France); Cotton, W. [NRAO, 520 Edgemont Road, Charlottesville, VA 22903 (United States)] [NRAO, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Uchiyama, H.; Nobukawa, M.; Tsuru, T. G. [Cosmic Ray Group, Physics, Kyoto University, Kitashirakawa-Oiwake-Cho, Sakyo, Kyoto 606-8502 (Japan)] [Cosmic Ray Group, Physics, Kyoto University, Kitashirakawa-Oiwake-Cho, Sakyo, Kyoto 606-8502 (Japan); Heinke, C. [Department of Physics, Room 238 CEB, University of Alberta, Edmonton, AB T6G 2G7 (Canada)] [Department of Physics, Room 238 CEB, University of Alberta, Edmonton, AB T6G 2G7 (Canada)

2013-01-01T23:59:59.000Z

449

MCNP6 Cosmic-Source Option  

SciTech Connect (OSTI)

MCNP is a Monte Carlo radiation transport code that has been under development for over half a century. Over the last decade, the development team of a high-energy offshoot of MCNP, called MCNPX, has implemented several physics and algorithm improvements important for modeling galactic cosmic-ray (GCR) interactions with matter. In this presentation, we discuss the latest of these improvements, a new Cosmic-Source option, that has been implemented in MCNP6.

McKinney, Gregg W [Los Alamos National Laboratory; Armstrong, Hirotatsu [Los Alamos National Laboratory; James, Michael R [Los Alamos National Laboratory; Clem, John [University of Delaware, BRI; Goldhagen, Paul [DHS, National Urban Security Technology Laboratory

2012-06-19T23:59:59.000Z

450

Cosmic Glows  

E-Print Network [OSTI]

This is the obligatory Cosmic Microwave Background review. I discuss the current status of CMB anisotropies, together with some points on the related topic of the Far-Infrared Background. We have already learned a number of important things from CMB anisotropies. Models which are in good shape have: approximately flat geometry; cold dark-matter, plus something like a cosmological constant; roughly scale invariant adiabatic fluctuations; and close to Gaussian statistics. The constraints from the CMB are beginning to be comparable to those from other cosmological measurements. With a wealth of new data coming in, it is expected that CMB anisotropies will soon provide the most stringent limits on fundamental cosmological parameters, as well as probing high energy particle physics and the Dark Ages of astrophysics. Nudge, nudge. Wink, wink. Say no more.

Douglas Scott

1999-12-02T23:59:59.000Z

451

Simulating Cosmic Reionization  

E-Print Network [OSTI]

The Cosmic Dark Ages and the Epoch of Reionization constitute a crucial missing link in our understanding of the evolution of the intergalactic medium and the formation and evolution of galaxies. Due to the complex nature of this global process it is best studied through large-scale numerical simulations. This presents considerable computational challenges. The dominant contributors of ionizing radiation were dwarf galaxies. These tiny galaxies must be resolved in very large cosmological volumes in order to derive their clustering properties and the corresponding observational signatures correctly, which makes this one of the most challenging problems of numerical cosmology. We have recently performed the largest and most detailed simulations of the formation of early cosmological large-scale structures and their radiative feedback leading to cosmic reionization. This was achieved by running extremely large (up to 29 billion-particle) N-body simulations of the formation of the Cosmic Web, with enough particles and sufficient force resolution to resolve all the galactic halos with total masses larger than 10^8 Solar masses in computational volumes of up to (163 Mpc)^3. These results were then post-processed by propagating the ionizing radiation from all sources by using fast and accurate ray-tracing radiative transfer method. Both of our codes are parallelized using a combination of MPI and OpenMP and to this date have been run efficiently on up to 2048 cores (N-body) and up to 10000 cores (radiative transfer) on the newly-deployed Sun Constellation Linux Cluster at the Texas Advanced Computing Center. In this paper we describe our codes, parallelization strategies, scaling and some preliminary scientific results. (abridged)

Ilian T. Iliev; Paul R. Shapiro; Garrelt Mellema; Hugh Merz; Ue-Li Pen

2008-06-17T23:59:59.000Z

452

Study of the chemical composition of high energy cosmic rays using the muon LDF of EAS between $10^{17.25}$ eV and $10^{17.75}$ eV  

E-Print Network [OSTI]

We explore the feasibility of estimating primary cosmic ray composition at high energies from the study of two parameters of Extensive Air Showers (EAS) at ground and underground level with Monte Carlo simulations using the new EPOS and QGSJETII hadronic models tuned with LHC data. Namely, the slope and density at a given distance of the muon lateral distribution function are analysed in this work. The power to discriminate primary masses is quantified in terms of merit factor for each parameter. The analysis considers three different primary particles (proton, iron and gamma), four different zenith angles (0$^{\\circ}$, 15$^{\\circ}$, 30$^{\\circ}$ and 45$^{\\circ}$) and primary energies of $10^{17.25}$ eV, $10^{17.50}$ eV and $10^{17.75}$ eV.

Tapia, A; Snchez, F; Croce, A Sedoski; Figueira, J M; Garca, B; Gonzlez, N; Josebachuili, M; Ravignani, D; Wundheiler, B; Etchegoyen, A

2015-01-01T23:59:59.000Z

453

Fermilab | Science at Fermilab | Experiments & Projects | Cosmic Frontier  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

photo-cosmic photo-cosmic Cosmic Frontier Particle physics experiments at the Cosmic Frontier use the cosmos as a laboratory to investigate the fundamental laws of physics. Researchers use detectors to study particles from space as they approach and enter our atmosphere in forms such as cosmic rays, gamma rays and neutrinos emitted by the sun. These experiments allow researchers to test theories about how the universe was formed, what it is made of and what its future holds. Experiments at the Cosmic Frontier may have the best chance of discovering the nature of dark matter and dark energy. Theorists have concluded that these two mysterious materials constitute 96 percent of the universe and may be responsible for its formation and accelerating expansion. WIMPS and dark matter

454

A Common Solution of Two Cosmic Puzzles  

E-Print Network [OSTI]

The origin of the diffuse extragalactic gamma-ray background, which was measured with the large area telescope (LAT) aboard the Fermi satellite at energy below 820 GeV, and of the diffuse cosmic background of neutrinos, which was observed at much higher energies with the IceCube detector deep under the south pole ice, are among the current unsolved major cosmic puzzles. Here we show that their properties indicate a common origin: the decay of mesons produced in collisions of cosmic rays accelerated in relativistic jets with matter in/near source. Moreover, their properties are those expected if their common source is the highly relativistic jets that produce the long duration gamma ray bursts in core collapse supernovae of type Ic, which take place mostly in the densest regions of giant molecular clouds in star forming galaxies.

Dado, Shlomo

2014-01-01T23:59:59.000Z

455

Collecting heat during the day, observing the sky at night : the use of a heliostat field near Almeria to search for cosmic gamma rays.  

E-Print Network [OSTI]

??The GRAAL experiment (Gamma Ray Astronomy at ALmeria) is the result of the conversion of a solar power plant near Almeria into a Cherenkov telescope (more)

Diaz Trigo, Maria

2002-01-01T23:59:59.000Z

456

Observation of the Crab Nebula in Soft Gamma Rays with the Nuclear Compton Telescope  

E-Print Network [OSTI]

Gamma-ray bursts . . . . . . . . . . . . . . . . . . . 1.268] G. J. Fishman. The gamma-ray burst capabilities of BATSEOlson. Observations of Gamma- Ray Bursts of Cosmic Origin.

Bandstra, Mark ShenYu

2010-01-01T23:59:59.000Z

457

On the variability of afterglows from cosmic gamma-ray burststhe possibility of a transition to a nonrelativistic motion  

Science Journals Connector (OSTI)

Variability on time scales ?t gamma-ray bursts (GRBs). It is well known that...2?104 cm?3, or a stellar wind with ? ? 10?5?10?4

R. A. Burenin

2007-12-01T23:59:59.000Z

458

Gamma-ray Astronomy  

E-Print Network [OSTI]

The relevance of gamma-ray astronomy to the search for the origin of the galactic and, to a lesser extent, the ultra-high-energy cosmic rays has long been recognised. The current renaissance in the TeV gamma-ray field has resulted in a wealth of new data on galactic and extragalactic particle accelerators, and almost all the new results in this field were presented at the recent International Cosmic Ray Conference (ICRC). Here I summarise the 175 papers submitted on the topic of gamma-ray astronomy to the 30th ICRC in Merida, Mexico in July 2007.

Jim Hinton

2007-12-20T23:59:59.000Z

459

Sustainable buildings itu.int/ITU-T/climatechange/ess  

E-Print Network [OSTI]

Sustainable buildings itu.int/ITU-T/climatechange/ess #12;Acknowledgements This document is part at: www.itu.int/ITU- T/climatechange/ess/index.html If you would like to provide any additional

460

Interpretation of radio continuum and molecular line observations of Sgr B2: freefree and synchrotron emission, and implications for cosmic rays  

Science Journals Connector (OSTI)

......structure could be as large as a factor 2...the Earth's atmosphere based on fig...production of large numbers of positrons...where nup is the plasma frequency and...interest being 330 MHz, the Razin effect...the Gamma Ray Large Area Space Telescope......

R. J. Protheroe; J. Ott; R. D. Ekers; D. I. Jones; R. M. Crocker

2008-10-21T23:59:59.000Z

Note: This page contains sample records for the topic "int cosmic ray" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.