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1

Ultrahigh Energy Cosmic Rays Detection  

SciTech Connect

The paper describes methods used for the detection of cosmic rays with energies above 1018 eV (UHECR, UltraHigh Energy Cosmic Rays). It had been anticipated there would be a cutoff in the energy spectrum of primary cosmic rays around 3{center_dot}1019 eV induced by their interaction with the 2.7 deg. K primordial photons. This has become known as the GZK cutoff. However, several showers have been detected with estimated primary energy exceeding this limit.

Aramo, Carla [Istituto Nazionale di Fisica Nucleare - Sezione di Napoli, Complesso Universitario di Monte Sant'Angelo, Via Cintia, 80126 - Naples (Italy)

2005-10-12

2

Research Concerning Detection of Cosmic Rays  

NASA Astrophysics Data System (ADS)

Throughout my academic career at Loyola I have carried out research with the Loyola University Cosmic Event Detection System concerning the possibility of detection of ultra high energy cosmic rays (UHECRs) based on radio meteor scattering methods. This research was furthered through summer internships and research fellowships at Adler Planetarium Chicago and Stony Brook University in New York. At Adler Planetarium we used a helium balloon carrying a Geiger counter and other equipment to record the cosmic ray flux at various points in the atmosphere. The results clearly show the flux depends on the atmospheric density. At Stony Brook University I studied their advanced system for detecting cosmic rays in similar manner to radio meteor scattering principles. Research there focused on detection algorithms and also on the possibility of utilizing Digital Tv (DTv) signals for further research. Through the research a solid understanding of cosmic rays was formed including topics such as origins and energy scales of cosmic rays, both of which pose unanswered questions. )

Grady, Maxwell; Cunningham, John; Kuhlmann, Steve; Spinka, Hal; Underwood, Dave; Hammergren, Mark

2010-02-01

3

Cosmic Ray Muon Radiography for Contraband Detection.  

SciTech Connect

The threat of the detonation of a nuclear device in a major US city has prompted research aimed at providing more robust border surveillance for contraband nuclear material. Existing radiographic techniques are inefficient for the detection of shielded material. These techniques also involve radiation hazards, real and perceived. We have invented a new technique which is capable of passively detecting small quantities of shielded SNM in a short time by using the multiple scattering of cosmic ray muons as a radiographic probe. A chief advantage of this technique is that no artificial dose is applied to the object being radiographed. We describe the technique and discuss experimental and simulated results.

Schultz, Larry J.; Borozdin, Konstantin N.; Gomez, John J.; Hogan, Gary E.; Morris, Chris L.; Priedhorsky, William C.; Saunders, Alexander

2003-07-11

4

Cosmic Ray Inspection and Passive Tomography for SNM Detection  

Microsoft Academic Search

The Cosmic Ray Inspection and Passive Tomography (CRIPT) project has recently started investigating the detection of illicit Special Nuclear Material in cargo using cosmic ray muon tomography and complementary neutron detectors. We are currently performing simulation studies to help with the design of small scale prototypes. Based on the prototype tests and refined simulations, we will determine whether the muon

John Armitage; Douglas Bryman; Thomas Cousins; Grant Gallant; Andrew Jason; Guy Jonkmans; Scott Noël; Gerald Oakham; Trevor J. Stocki; David Waller

2009-01-01

5

Detection techniques of ultra high energy cosmic rays  

SciTech Connect

Several detection techniques in current high-energy cosmic rays are examined. The results of some experiments are discussed and a review of the future projects is made, emphasizing their discovery potential in accordance with their aperture.

Salazar, H. [Facultad de Ciencias Fisico-Matemaaticas, Universidad Autonoma de Puebla, Puebla, Pue. (Mexico)

1998-10-05

6

Radar Detection of High Energy Cosmic Ray Showers  

NASA Astrophysics Data System (ADS)

The radar detection technique for High Energy Cosmic Ray Shower detection has been investigated in this collaborative work. High Energy Cosmic Ray Showers produce disk-like ionization front which moves with relativistic speed in our atmosphere. We study the reflection of radio waves such as the ones from commercial radio and TV stations from the relativistic moving front. The reflected wave experiences a high blue-shift in frequency due to relativistic Doppler Effect. The feasibility study of detection of showers via this method and the benefits will be presented.

Kryemadhi, Abaz; Bakunov, Michael; Maslov, Alex; Novokovskaya, Alina

2012-03-01

7

Cosmic Rays  

Microsoft Academic Search

For many years cosmic rays provided the most important source of energetic particles for studies of subatomic physics. Today, cosmic rays are being studied as a natural phenomenon that can tell us much about both the Earth's environment in space and distant astrophysical processes. Cosmic rays are naturally occurring energetic particles-mainly ions- with kinetic energies extending from just above thermal

J. R. Jokipii

1998-01-01

8

Microwave detection of Ultra-High Energy Cosmic Rays  

NASA Astrophysics Data System (ADS)

A novel detection technique for Ultra-High Energy Cosmic Rays based on microwave emission from the extensive air showers may provide large area coverage with 100% duty cycle at low cost. The status and prospects of several complementary R&D projects for GHz detectors is reviewed.

Privitera, P.

2011-09-01

9

The role of Cherenkov radiation in the detection of ultra-high-energy cosmic rays  

NASA Astrophysics Data System (ADS)

A brief historical overview of the role of Cherenkov radiation in the detection of cosmic rays is given. A current application, the detection of ultra-high-energy cosmic rays with the Pierre Auger Observatory, is described.

Watson, A. A.

2005-11-01

10

Student Projects in Cosmic Ray Detection  

ERIC Educational Resources Information Center

|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. 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…

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

2009-01-01

11

Radar Detection of ultra high energy cosmic rays  

NASA Astrophysics Data System (ADS)

We revisit the radar echo technique as an approach to detect ultra high energy cosmic rays (UHECR). The UHECR extensive air showers produce disk-like ionization fronts propagating with a relativistic speed and creating fast decaying plasma. We study the reflection of a radio wave, such as the one from a radar transmitter or commercial radio and TV station, from the ionization front. The reflected wave will be frequency up-shifted due to relativistic Doppler effect. The amplitude of the reflected wave depends strongly on velocity of the front, and density and collision frequency of the plasma behind it. The returned power will be shown for typical extensive air shower parameters. )

Kryemadhi, Abaz; Bakunov, Michael; Maslov, Alex; Novokovskaya, Alina

2010-02-01

12

Cosmic Rays  

NASA Astrophysics Data System (ADS)

For many years cosmic rays provided the most important source of energetic particles for studies of subatomic physics. Today, cosmic rays are being studied as a natural phenomenon that can tell us much about both the Earth's environment in space and distant astrophysical processes. Cosmic rays are naturally occurring energetic particles-mainly ions- with kinetic energies extending from just above thermal energies to more than 1020 electron volts (eV). They constantly bombarded the Earth from all directions, with more than 10's particles having energies greater than 1 MeV striking the top of the Earth's atmosphere each second. The broad maximum in the spectrum at 108 - 109 eV defines the typical cosmic rays proton having approximately 109 eV. The abundances of certain unstable isotopes in meteorites show that cosmic rays have been present at nearly their current level for hundreds of millions of years. Studies of electromagnetic waves produced by cosmic rays in distant astrophysical sources reveal that they are present throughout the disk and halo of our galaxy and in other galaxies as well. Cosmic rays are now believed to be produced naturally in astrophysical plasmas, nearly all by a process called diffusive shock acceleration, which occurs naturally at collisionless shock waves. Observations of cosmic rays began in the early part of this century when C.TR. Wilson, using his cloud chamber, studied the puzzlingly high level of atmospheric ionization. In 1912, with balloon-borne ionization detectors, Victor Hess showed that this ionization increased with increasing altitude and concluded that radiation was coming from above the atmosphere, a discovery which earned him the Nobel Prize in 1936.

Jokipii, J. R.

1998-01-01

13

Cosmic Ray Inspection and Passive Tomography for SNM Detection  

SciTech Connect

The Cosmic Ray Inspection and Passive Tomography (CRIPT) project has recently started investigating the detection of illicit Special Nuclear Material in cargo using cosmic ray muon tomography and complementary neutron detectors. We are currently performing simulation studies to help with the design of small scale prototypes. Based on the prototype tests and refined simulations, we will determine whether the muon tracking system for the full scale prototype will be based on drift chambers or extruded scintillator trackers. An analysis of the operations of the Port of Montreal has determined how long muon scan times should take if all or a subset of the cargo is to be screened. As long as the throughput of the muon system(s) is equal to the rate at which containers are unloaded from ships, the impact on port operations would not be great if a muon scanning stage were required for all cargo. We also show preliminary simulation results indicating that excellent separation between Al, Fe and Pb is possible under ideal conditions. The discrimination power is reduced but still significant when realistic momentum resolution measurements are considered.

Armitage, John; Oakham, Gerald [Department of Physics, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6 (Canada); Bryman, Douglas [Advanced Applied Physics Solutions, 4004 Westbrook Mall, Vancouver, BC, V6T 2A3 (Canada); Cousins, Thomas; Noeel, Scott [International Safety Research, 38 Colonnade Rd. N. Ottawa, ON, K2E 7J6 (Canada); Gallant, Grant [Canadian Border Services Agency, Laboratory and Scientific Services Directorate, 79 Bentley Avenue, Ottawa, ON, K2E 6T7 (Canada); Jason, Andrew [Los Alamos National Laboratories, MS H817, Los Alamos National Laboratory, Los Alamos, NM, USA 87544 (United States); Jonkmans, Guy [Atomic Energy of Canada Limited, Chalk River Laboratories, Chalk River, ON, K0J 1J0 (Canada); Stocki, Trevor J. [Radiation Protection Bureau, Health Canada, 775 BrookfieldRd, A.L. 6302D1, Ottawa, ON, K1A 1C1 (Canada); Waller, David [Defence Research and Development Canada-Ottawa, 3701 Carling Avenue, Ottawa, ON, K1A 0Z4 (Canada)

2009-12-02

14

Cosmic Ray Inspection and Passive Tomography for SNM Detection  

NASA Astrophysics Data System (ADS)

The Cosmic Ray Inspection and Passive Tomography (CRIPT) project has recently started investigating the detection of illicit Special Nuclear Material in cargo using cosmic ray muon tomography and complementary neutron detectors. We are currently performing simulation studies to help with the design of small scale prototypes. Based on the prototype tests and refined simulations, we will determine whether the muon tracking system for the full scale prototype will be based on drift chambers or extruded scintillator trackers. An analysis of the operations of the Port of Montreal has determined how long muon scan times should take if all or a subset of the cargo is to be screened. As long as the throughput of the muon system(s) is equal to the rate at which containers are unloaded from ships, the impact on port operations would not be great if a muon scanning stage were required for all cargo. We also show preliminary simulation results indicating that excellent separation between Al, Fe and Pb is possible under ideal conditions. The discrimination power is reduced but still significant when realistic momentum resolution measurements are considered.

Armitage, John; Bryman, Douglas; Cousins, Thomas; Gallant, Grant; Jason, Andrew; Jonkmans, Guy; Noël, Scott; Oakham, Gerald; Stocki, Trevor J.; Waller, David

2009-12-01

15

Towards the installation and use of an extended array for cosmic ray detection: The EEE Project  

Microsoft Academic Search

The Extreme Energy Events (EEE) project started to use an array of cosmic ray telescopes for muon detection, distributed over the italian territory. The use of such telescopes, based on Multigap Resistive Plate Chambers (MRPC) allows the study of the local muon flux, the detection of cosmic ray showers and the search for correlations between distant showers. The project is

M. Abbrescia; A. Alici; S. An; R. Antolini; A. Badalà; Y. W. Baek; R. Baldini Ferroli; G. Bencivenni; F. Blanco; E. Bressan; A. Chiavassa; C. Chiri; C. Cicalò; L. Cifarelli; E. Coccia; F. Coccetti; A. De Caro; D. De Gruttola; S. De Pasquale; M. D'Incecco; F. L. Fabbri; V. Frolov; M. Garbini; C. Guarnaccia; C. Gustavino; D. Hatzifotiadou; G. Imponente; J. S. Kim; M. M. Kim; P. La Rocca; F. Librizzi; A. Maggiora; H. Menghetti; S. Miozzi; R. Moro; F. Noferini; P. Pagano; M. Panareo; G. S. Pappalardo; C. Petta; G. Piragino; R. Preghenella; F. Riggi; F. Romano; G. Russo; G. Sartorelli; C. Sbarra; G. Scioli; M. Selvi; S. Serci; E. Siddi; H. Wenninger; M. C. S. Williams; C. Zampolli; A. Zichichi; R. Zuyeuski

2009-01-01

16

Introduction to Cosmic Rays  

NASA Astrophysics Data System (ADS)

These lecturers were done to introduce the students of the Third School of Cosmic Rays and Astrophysics to the world of Cosmic Rays. In these proceedings, I am covering the basic of what we covered in these lecturers. We discussed also about neutrino physics, gamma ray physics and detection of cosmic rays, but we are not covering these last topics, since are the main topics of other lecturers of the School. We include in these proceedings an introduction to the importance and history of the cosmic rays, a description of the spectrum of the cosmic rays, the geomagnetic effects, acceleration mechanisms, extensive air shower generation and the physical processes involved, resulting in the explanation of a toy model of the development of the air shower.

Chirinos, J.

2009-04-01

17

Detection of a cosmic ray with measured energy well beyond the expected spectral cutoff due to cosmic microwave radiation  

Microsoft Academic Search

We report the detection of a 51 Joule (3.2 +\\/- 0.9 x 1020 eV) cosmic ray by the Fly's Eye air shower detector in Utah. This is substantially greater than the energy of any previously reported cosmic ray. A Greisen-Zatsepin-Kuz'min cutoff of the energy spectrum (due to pion photoproduction energy losses) should occur below this energy unless the highest energy

D. J. Bird; S. C. Corbato; H. Y. Dai; J. W. Elbert; K. D. Green; M. A. Huang; D. B. Kieda; S. Ko; C. G. Larsen; E. C. Loh; M. Z. Luo; M. H. Salamon; J. D. Smith; P. Sokolsky; P. Sommers; J. K. K. Tang; S. B. Thomas

1995-01-01

18

Generation, propagation, and detection of high energy solar cosmic rays  

Microsoft Academic Search

The data on energetic (E ? 1012eV) solar cosmic ray generation are presented for the event of September 29, 1989. Charged particle acceleration mechanisms in the flares of an energy below E = 1011 - 1012eV are substantiated.

V. V. Borog; A. Yu. Burinsky; V. V. Dronov; E. V. Kolomeets; V. M. Smirnov; E. A. Chebakova

1997-01-01

19

Hoping to indirectly detect Dark Matter with cosmic rays  

NASA Astrophysics Data System (ADS)

Dark Matter constitutes more that 80% of the total amount of matter in the Universe, yet almost nothing is known about its nature. A powerful investigation technique is that of searching for the products of annihilations of Dark Matter particles in the galactic halo, on top of the ordinary cosmic rays. Recent data from the PAMELA and FERMI satellites and a number of balloon experiment have reported unexpected excesses in the measured fluxes of cosmic rays. Are these the first direct evidences for Dark Matter? If yes, which DM models and candidates can explain these anomalies (in terms of annihilations) and what do they imply for future searches? What are the constraints from gamma rays measurements and cosmology? [Report number: Saclay T-10/098, CERN-PH-TH/2010-183].

Cirelli, Marco

2010-11-01

20

Cosmic Rays  

NSDL National Science Digital Library

This series of web pages, authored and curated by David P. Stern, gives an elementary discussion of cosmic rays, followed by sections on high energy particles in the universe and high-energy particles from the Sun. It describes the existence particles whose velocity approaches that of light, their probable sources, and their measurement. This is part of a large work, "The Exploration of the Earth's Magnetosphere", that gives a non-mathematical introduction to planetary and solar magnetic fields, space weather, aurora, and charged particle motion. A Spanish translation is available.

Peredo, Mauricio; Mendez, J.; Stern, David P. (David Peter), 1931-

2009-04-21

21

Development of the Cosmic-Ray Muon Detection System for Probing Internal-Structure of a Volcano  

Microsoft Academic Search

Very high-energy cosmic-ray muons penetrating through a mountain enable us to probe the internal structure of volcanoes. An\\u000a improved cosmic-ray muon detection system comprising two segmented detectors with multiplicity cut of the soft components\\u000a of cosmic rays was developed. The test measurement for the volcano Mt. Asama is described.

H. Tanaka; K. Nagamine; N. Kawamura; S. N. Nakamura; K. Ishida; K. Shimomura; I. Katsuhiko; S. Koichiro

2001-01-01

22

FPGA Based Signal-Processing for Radio Detection of Cosmic Rays  

Microsoft Academic Search

For the observation of ultra high-energy cosmic rays (UHECRs) by the detection of their coherent radio emission an FPGA based trigger and radio frequency interference (RFI) filter was developed. Using radio detection, the electromagnetic part of an air shower in the atmosphere may be studied in detail, thus providing information complementary to that obtained by water Cherenkov detectors which are

Adrian Schmidt; Hartmut Gemmeke; Andreas Haungs; Karl-Heinz Kampert; Christoph Ruhle; Zbigniew Szadkowski

2011-01-01

23

LOPES: detecting radio emission from cosmic ray air showers  

NASA Astrophysics Data System (ADS)

Radio pulses emitted in the Atmosphere during the air shower development of high-energy primary cosmic rays were measured during the late 1960ies in the frequency range from 2 MHz to 520 MHz. Mainly due to difficulties with radio interference these measurements ceased in the late 1970ies. LOFAR (Low Frequency Array) is a new digital radio interferometer under development. Using high bandwidth ADCs and fast data processing it it will be able to filter out most of the interference. By storing the whole waveform information in digital form one can analyze transient events like air showers even after they have been recorded. To test this new technology and to demonstrate its ability to measure air showers a "LOFAR Prototype Station" (LOPES) is set up to operate in conjunction with an existing air shower array (KASCADE-Grande). The first phase consisting of 10 antennas is already running. It operates in the frequency range of 40 to 80 MHz, using simple short dipole antennas and direct 2nd Nyquist sampling of the incoming wave. It has proven to be able to do simple astronomical measurements, like imaging of a solar burst. It has also demonstrated how digital interference suppression and beamforming can overcome the problem of radio interference and pick out air shower events.

Horneffer, Andreas; Antoni, T.; Apel, W. D.; Badea, F.; Bekk, K.; Bercuci, A.; Bertaina, M.; Blümer, H.; Bozdog, H.; Brancus, I. M.; Brüggemann, M.; Buchholz, P.; Büttner, C.; Chiavassa, A.; Daumiller, K.; de Vos, C. Marco; Doll, P.; Engel, R.; Engler, J.; Falcke, Heino; Fessler, F.; Ghia, P. L.; Gils, H. J.; Glasstetter, R.; Haungs, A.; Heck, D.; Hörandel, J. R.; Huege, T.; Kampert, Karl-Heinz; Kant, G. W.; Klages, H. O.; Kolotaev, Y.; Maier, Gert; Mathes, H. J.; Mayer, Helmut J.; Milke, J.; Morello, C.; Müller, M.; Navarra, G.; Obenland, R.; Oehlschläger, J.; Ostapchenko, S.; Petcu, Mihai; Plewnia, S.; Rebel, H.; Risse, A.; Roth, M.; Schieler, Harald; Scholz, J.; Stümpert, M.; Thouw, T.; Trinchero, G. C.; Ulrich, H.; Valchierotti, S.; van Buren, J.; Walkowiak, W.; Weindl, A.; Wochele, J.; Zabierowski, J.; Zagromski, S.

2004-09-01

24

Detection of cosmic gamma-rays using a heliostat field  

NASA Astrophysics Data System (ADS)

Gamma-Ray telescopes based on a solar plant are able to accurately measure the spatial distribution and time structure of the Cherenkov shower front. Although this information should be sufficient for the reconstruction of several primary parameters, it will be shown that the restricted field of view of the optical detection system and the limited sampling of a realistic heliostat array impose severe limitations.

Arqueros, F.; Ballestrin, J.; Borque, D. M.; Diaz Trigo, M.; Enriquez, R.; Gebauer, H.-J.; Plaga, R.

2001-08-01

25

Solar cosmic ray phenomena  

Microsoft Academic Search

This review attempts to present an integrated view of the several types of solar cosmic ray phenomena. The relevant large and small scale properties of the interplanetary medium are first surveyed, and their use in the development of a quantitative understanding of the cosmic ray propagation processes summarised. Solar cosmic ray events, in general, are classified into two phenomenological categories:

K. G. McCracken; U. R. Rao

1970-01-01

26

Imaging Algorithms for Cosmic Ray Muon Radiography Detection of Nuclear Materials  

Microsoft Academic Search

Cosmic ray muon radiography which has good penetration ability and is sensitive to high-Z materials, is an effective method to detect shielded nuclear materials. This paper summarizes methods developed to process muon radiography in Tsinghua University. The methods include detector data correction, reconstruction algorithms (maximum likelihood scattering, MLS, and the maximum likelihood scattering and displacement, MLSD) acceleration, and the modification

Yuanyuan Liu; Zhiqiang Chen; Ziran Zhao; Li Zhang; Zhentian Wang

2009-01-01

27

Cosmic ray muon tomography system using drift chambers for the detection of Special Nuclear Materials  

Microsoft Academic Search

The smuggling of illicit Special Nuclear Materials (SNM) and Radiological Materials (RM) is a major security concern. Current radiation detection systems for cargo are not sensitive to well-shielded nuclear materials. The Muon Scattering Tomography (MST) method that we are developing might be a solution to this problem. It is based on the measurement of multiple scattering of cosmic ray-induced muons,

V. Anghel; J. Armitage; J. Botte; K. Boudjemline; D. Bryman; E. Charles; T. Cousins; A. Erlandson; G. Gallant; C. Jewett; G. Jonkmans; Z. Liu; S. Noel; G. Oakham; T. J. Stocki; M. Thompson; D. Waller

2010-01-01

28

Thunderstorm correlated enhancements of Cosmic Ray flux, detected at mt. Aragats  

Microsoft Academic Search

The cosmic rays ionize enough the at- mosphere to be questioned as possible triggers of the thunderstorms. A mechanism proposed by A. Gurevich and his collaborators suggest that show- ers of energetic particles produced by high-energy cosmic rays in the terrestrial atmosphere might provide a conductive path that initiates lightning. Because cosmic-ray air showers do not produce enough particles for

Ashot Chilingarian; Ara Daryan; Laura Melkumyan

29

Detection techniques of radio emission from ultra high energy cosmic rays  

NASA Astrophysics Data System (ADS)

We discuss recent and future efforts to detect radio signals from extended air showers at the Pierre Auger Observatory in Malargue, Argentina. With the advent of low-cost, high-performance digitizers and robust digital signal processing software techniques, radio detection of cosmic rays has resurfaced as a promising measurement system. The inexpensive nature of the detector media (metallic wires, rods or parabolic dishes) and economies of scale working in our favor (inexpensive high-quality C-band amplifiers and receivers) make an array of radio antennas an appealing alternative to the expense of deploying an array of Cherenkov detector water tanks or 'fly's eye' optical telescopes for fluorescence detection. The calorimetric nature of the detection and the near 100% duty cycle gives the best of both traditional detection techniques. The history of cosmic ray detection detection will be discussed. A short review on the astrophysical properties of cosmic rays and atmospheric interactions will lead into a discussion of two radio emission channels that are currently being investigated.

Morris, Chad M.

30

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

NASA Astrophysics Data System (ADS)

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 expected values 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 ˜670 K, corresponding to ˜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.

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

2008-11-01

31

Axions and cosmic rays  

NASA Astrophysics Data System (ADS)

We investigate the propagation of a charged particle in a spatially constant but time-dependent pseudoscalar background. Physically, this pseudoscalar background could be provided by a relic axion density. The background leads to an explicit breaking of Lorentz invariance; processes such as p ? p? or e ? e? are consequently possible under some kinematic constraints. The phenomenon is described by the QED Lagrangian extended with a Chern-Simons term that contains a four-vector characterizing the breaking of Lorentz invariance induced by the time-dependent background. While the induced radiation (similar to the Cherenkov effect) is too small to influence the propagation of cosmic rays significantly, the hypothetical detection of the photons radiated by high-energy cosmic rays via this mechanism would provide an indirect way to verify the cosmological relevance of axions. We discuss the order of magnitude of the effect.

Espriu, D.; Renau, A.

2012-02-01

32

X-ray Emissions Detected From Elusive Cosmic Objects  

NASA Astrophysics Data System (ADS)

A type of celestial object that has long stumped astronomers has been found to emit X-rays, thus proving a theory of how the objects form. Dr. Steven Pravdo of NASA's Jet Propulsion Laboratory, Pasadena, Calif., and other scientists have concluded that these objects, called Herbig Haro objects, are produced by high velocity shocks. Pravdo is the lead author of a paper published in the Oct. 18 issue of the journal Nature. Herbig Haro objects are found in regions where new stars are forming. They are nebulas, or dust and gas clouds. They form when high-velocity gas emitted from young stars collides with clouds of interstellar material. The collision heats the gas in the surrounding nebula to sufficiently high temperatures to produce X-rays. Observations for the past 20 years showed no evidence of X-ray emission from these objects, which are named for astronomers George Herbig and Guillermo Haro. Previous instruments lacked the resolution and sensitivity necessary to 'see' these X-rays. The discovery of the X-ray emissions was possible through the very powerful Advanced CCD Imaging Spectrometer on NASA's Chandra X-ray Observatory, which has been in orbit since 1999. On Oct. 8, 2000, astrophysicists used the instrument to study HH2, one of the brightest and closest Herbig Haro objects in the Orion Nebula. They determined that HH2 contains shock-heated material with a temperature of about 1 million degrees Kelvin. Pravdo and his team used three criteria to rule out the possibility that the emissions came from any other source. First, Chandra's high spatial resolution pinpointed the location of the X-rays at HH2. Second, the X-rays appeared to be covering a region bigger than a star. Third, the temperature of the X-rays was about 1 million degrees, cooler than nearby X-ray stars. One million degrees is about the temperature expected if material moving at about 300 kilometers per second (about 600,000 miles per hour) collides. At this speed, you could go from Los Angeles to San Diego and back in one second. The principal investigator of the Advanced CCD Imaging Spectrometer, Dr. Gordon Garmire of Pennsylvania State University, University Park, is a co-author of the paper. Other co-authors include Drs. Yohko Tsuboi, Yoshitomo Maeda and Eric Feigelson, all from Pennsylvania State University, and Dr. John Bally from the University of Colorado, Boulder. The Advanced CCD Imaging Spectrometer X-ray camera was developed for NASA by Pennsylvania State University and the Massachusetts Institute of Technology, Cambridge, Mass. NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program. TRW, Inc., Redondo Beach, Calif., is the prime contractor for the spacecraft. The Smithsonian's Chandra X-ray Center controls science and flight operations from Cambridge, Mass. Images associated with this release are available on the World Wide Web at: http://chandra.harvard.edu AND http://chandra.nasa.gov The Chandra X-ray Observatory is managed for NASA by the Smithsonian Astrophysical Observatory, Cambridge, Mass. JPL is managed for NASA by the California Institute of Technology in Pasadena.

2001-10-01

33

Detection and imaging of atmospheric radio flashes from cosmic ray air showers  

NASA Astrophysics Data System (ADS)

The nature of ultrahigh-energy cosmic rays (UHECRs) at energies >1020eV remains a mystery. They are likely to be of extragalactic origin, but should be absorbed within ~50Mpc through interactions with the cosmic microwave background. As there are no sufficiently powerful accelerators within this distance from the Galaxy, explanations for UHECRs range from unusual astrophysical sources to exotic string physics. Also unclear is whether UHECRs consist of protons, heavy nuclei, neutrinos or ?-rays. To resolve these questions, larger detectors with higher duty cycles and which combine multiple detection techniques are needed. Radio emission from UHECRs, on the other hand, is unaffected by attenuation, has a high duty cycle, gives calorimetric measurements and provides high directional accuracy. Here we report the detection of radio flashes from cosmic-ray air showers using low-cost digital radio receivers. We show that the radiation can be understood in terms of the geosynchrotron effect. Our results show that it should be possible to determine the nature and composition of UHECRs with combined radio and particle detectors, and to detect the ultrahigh-energy neutrinos expected from flavour mixing.

Falcke, H.; Apel, W. D.; Badea, A. F.; Bähren, L.; Bekk, K.; Bercuci, A.; Bertaina, M.; Biermann, P. L.; Blümer, J.; Bozdog, H.; Brancus, I. M.; Buitink, S.; Brüggemann, M.; Buchholz, P.; Butcher, H.; Chiavassa, A.; Daumiller, K.; de Bruyn, A. G.; de Vos, C. M.; di Pierro, F.; Doll, P.; Engel, R.; Gemmeke, H.; Ghia, P. L.; Glasstetter, R.; Grupen, C.; Haungs, A.; Heck, D.; Hörandel, J. R.; Horneffer, A.; Huege, T.; Kampert, K.-H.; Kant, G. W.; Klein, U.; Kolotaev, Y.; Koopman, Y.; Krömer, O.; Kuijpers, J.; Lafebre, S.; Maier, G.; Mathes, H. J.; Mayer, H. J.; Milke, J.; Mitrica, B.; Morello, C.; Navarra, G.; Nehls, S.; Nigl, A.; Obenland, R.; Oehlschläger, J.; Ostapchenko, S.; Over, S.; Pepping, H. J.; Petcu, M.; Petrovic, J.; Plewnia, S.; Rebel, H.; Risse, A.; Roth, M.; Schieler, H.; Schoonderbeek, G.; Sima, O.; Stümpert, M.; Toma, G.; Trinchero, G. C.; Ulrich, H.; Valchierotti, S.; van Buren, J.; van Cappellen, W.; Walkowiak, W.; Weindl, A.; Wijnholds, S.; Wochele, J.; Zabierowski, J.; Zensus, J. A.; Zimmermann, D.

2005-05-01

34

Detection and imaging of atmospheric radio flashes from cosmic ray air showers.  

PubMed

The nature of ultrahigh-energy cosmic rays (UHECRs) at energies >10(20) eV remains a mystery. They are likely to be of extragalactic origin, but should be absorbed within approximately 50 Mpc through interactions with the cosmic microwave background. As there are no sufficiently powerful accelerators within this distance from the Galaxy, explanations for UHECRs range from unusual astrophysical sources to exotic string physics. Also unclear is whether UHECRs consist of protons, heavy nuclei, neutrinos or gamma-rays. To resolve these questions, larger detectors with higher duty cycles and which combine multiple detection techniques are needed. Radio emission from UHECRs, on the other hand, is unaffected by attenuation, has a high duty cycle, gives calorimetric measurements and provides high directional accuracy. Here we report the detection of radio flashes from cosmic-ray air showers using low-cost digital radio receivers. We show that the radiation can be understood in terms of the geosynchrotron effect. Our results show that it should be possible to determine the nature and composition of UHECRs with combined radio and particle detectors, and to detect the ultrahigh-energy neutrinos expected from flavour mixing. PMID:15902250

Falcke, H; Apel, W D; Badea, A F; Bähren, L; Bekk, K; Bercuci, A; Bertaina, M; Biermann, P L; Blümer, J; Bozdog, H; Brancus, I M; Buitink, S; Brüggemann, M; Buchholz, P; Butcher, H; Chiavassa, A; Daumiller, K; de Bruyn, A G; de Vos, C M; Di Pierro, F; Doll, P; Engel, R; Gemmeke, H; Ghia, P L; Glasstetter, R; Grupen, C; Haungs, A; Heck, D; Hörandel, J R; Horneffer, A; Huege, T; Kampert, K-H; Kant, G W; Klein, U; Kolotaev, Y; Koopman, Y; Krömer, O; Kuijpers, J; Lafebre, S; Maier, G; Mathes, H J; Mayer, H J; Milke, J; Mitrica, B; Morello, C; Navarra, G; Nehls, S; Nigl, A; Obenland, R; Oehlschläger, J; Ostapchenko, S; Over, S; Pepping, H J; Petcu, M; Petrovic, J; Plewnia, S; Rebel, H; Risse, A; Roth, M; Schieler, H; Schoonderbeek, G; Sima, O; Stümpert, M; Toma, G; Trinchero, G C; Ulrich, H; Valchierotti, S; van Buren, J; van Cappellen, W; Walkowiak, W; Weindl, A; Wijnholds, S; Wochele, J; Zabierowski, J; Zensus, J A; Zimmermann, D

2005-05-19

35

Detection of ultrahigh-energy cosmic rays and neutrinos by a lunar nanosatellite-borne radio receiver  

Microsoft Academic Search

The feasibility of ultrahigh-energy cosmic ray and neutrino detection by a lunar nanosatellite-borne radio receiver is discussed. The estimated values of the energy threshold and event rate for cosmic ray detection are found to be Eth(CR) ≈ 1018 eV, N(CR, E >= 1019 eV) ≈ a few hundreds of events per day, and N(CR, E >= 1020 eV) is more

V. A. Chechin; B. N. Lomonosov; K. M. Pichkhadze; N. G. Poluhina; V. A. Ryabov; V. K. Sysoev; V. A. Tsarev

2004-01-01

36

Cosmic Rays in Thunderstorms  

NASA Astrophysics Data System (ADS)

Cosmic Rays in Thunderstorms Cosmic rays are protons and heavier nuclei that constantly bombard the Earth's atmosphere with energies spanning a vast range from 109 to 1021 eV. At typical altitudes up to 10-20 km they initiate large particle cascades, called extensive air showers, that contain millions to billions of secondary particles depending on their initial energy. These particles include electrons, positrons, hadrons and muons, and are concentrated in a compact particle front that propagates at relativistic speed. In addition, the shower leaves behind a trail of lower energy electrons from ionization of air molecules. Under thunderstorm conditions these electrons contribute to the electrical and ionization processes in the cloud. When the local electric field is strong enough the secondary electrons can create relativistic electron run-away avalanches [1] or even non-relativistic avalanches. Cosmic rays could even trigger lightning inception. Conversely, strong electric fields also influence the development of the air shower [2]. Extensive air showers emit a short (tens of nanoseconds) radio pulse due to deflection of the shower particles in the Earth's magnetic field [3]. Antenna arrays, such as AERA, LOFAR and LOPES detect these pulses in a frequency window of roughly 10-100 MHz. These systems are also sensitive to the radiation from discharges associated to thunderstorms, and provide a means to study the interaction of cosmic ray air showers and the electrical processes in thunderstorms [4]. In this presentation we discuss the involved radiation mechanisms and present analyses of thunderstorm data from air shower arrays [1] A. Gurevich et al., Phys. Lett. A 165, 463 (1992) [2] S. Buitink et al., Astropart. Phys. 33, 1 (2010) [3] H. Falcke et al., Nature 435, 313 (2005) [4] S. Buitink et al., Astron. & Astrophys. 467, 385 (2007)

Buitink, Stijn; Scholten, Olaf; van den Berg, Ad; Ebert, Ute

2013-04-01

37

Origin of Cosmic Rays  

Microsoft Academic Search

Contents Introduction S 1. Primary Cosmic Rays Near the Earth a) Chemical composition b) Energy spectrum S 2. Radio-Astronomical Data a) Magnetic bremsstrahlung (synchrotron radiation) b) Certain results of observations and their interpretation (structure of the Galaxy, discrete sources) S 3. Lifetime of Cosmic Rays and Character of Their Motion in the Galaxy and the Metagalaxy a) Nuclear lifetime of

V. L. Ginzburg; S. I. Syrovatsky

1961-01-01

38

Prospects of detecting gamma-ray emission from galaxy clusters: Cosmic rays and dark matter annihilations  

NASA Astrophysics Data System (ADS)

We study the possibility for detecting gamma-ray emission from galaxy clusters. We consider (1) leptophilic models of dark matter (DM) annihilation that include a Sommerfeld enhancement (SFE), (2) different representative benchmark models of supersymmetric DM, and (3) cosmic-ray (CR) induced pion decay. Among all clusters/groups of a flux-limited x-ray sample, we predict Virgo, Fornax, and M49 to be the brightest DM sources and find a particularly low CR-induced background for Fornax. For a minimum substructure mass given by the DM free-streaming scale, cluster halos maximize the substructure boost for which we find a factor of ?1000. Since regions around the virial radius dominate the annihilation flux of substructures, the resulting surface brightness profiles are almost flat. This makes it very challenging to detect this flux with imaging atmospheric Cherenkov telescopes since their sensitivity drops approximately linearly with radius and they typically have 5-10 linear resolution elements across a cluster. Assuming cold dark matter with a substructure mass distribution down to an Earth mass and using extended Fermi upper limits, we rule out the leptophilic models in their present form in 28 clusters, and limit the boost from SFE in M49 and Fornax to be ?5. This corresponds to a limit on SFE in the Milky Way of ?3, which is too small to account for the increasing positron fraction with energy as seen by PAMELA and challenges the DM interpretation. Alternatively, if SFE is realized in nature, this would imply a limiting substructure mass of Mlim?>104M?—a problem for structure formation in most particle physics models. Using individual cluster observations, it will be challenging for Fermi to constrain our selection of DM benchmark models without SFE. The Fermi upper limits are, however, closing in on our predictions for the CR flux using an analytic model based on cosmological hydrodynamical cluster simulations. We limit the CR-to-thermal pressure in nearby bright galaxy clusters of the Fermi sample to ?10% and in Norma and Coma to ?3%. Thus, we will soon start to constrain the underlying CR physics such as shock acceleration efficiencies or CR transport properties.

Pinzke, Anders; Pfrommer, Christoph; Bergström, Lars

2011-12-01

39

Cosmic-ray astrochemistry.  

PubMed

Gas-phase chemistry in the interstellar medium is driven by fast ion-molecule reactions. This, of course, demands a mechanism for ionization, and cosmic rays are the ideal candidate as they can operate throughout the majority of both diffuse and dense interstellar clouds. Aside from driving interstellar chemistry via ionization, cosmic rays also interact with the interstellar medium in ways that heat the ambient gas, produce gamma rays, and produce light element isotopes. In this paper we review the observables generated by cosmic-ray interactions with the interstellar medium, focusing primarily on the relevance to astrochemistry. PMID:23812538

Indriolo, Nick; McCall, Benjamin J

2013-06-28

40

Radio detection of cosmic ray induced air showers at the Pierre Auger Observatory  

NASA Astrophysics Data System (ADS)

AERA—the Auger Engineering Radio Array—is currently being set up at the southern site of the Pierre Auger Observatory. AERA will explore the potential of the radio-detection technique to cosmic ray induced air showers with respect to the next generation of large-scale surface detectors. As AERA is co-located with the low-energy enhancements of the Pierre Auger Observatory, the observation of air showers in coincidence with the Auger surface and fluorescence detector will allow to study the radio emission processes in detail and to calibrate the radio signal. Finally, the combined reconstruction of shower parameters with three independent techniques promises new insights into the nature of cosmic rays in the transition region from 1017 to 1019 eV.Besides the detection of coherent radiation in the MHz frequency range, the setups AMBER—Air-shower Microwave Bremsstrahlung Experimental Radiometer—and MIDAS—MIcrowave Detection of Air Showers—prepare to check the possibility to detect air showers due the emission of molecular bremsstrahlung in the GHz range at the Auger site.This article presents the status of the radio-detection setups and discusses their physics potential as well as experimental challenges. Special focus is laid on the first stage of AERA which is the startup to the construction of a 20 km2 radio array.

For the Pierre Auger Collaboration Fliescher, Stefan

2012-01-01

41

Marshak Lecture: Hadrons and other secondaries underground (Problems of neutrino detection in cosmic rays)  

NASA Astrophysics Data System (ADS)

In the lecture the short historical review of the problem,the theory of hadron generation underground developed by us and experimental results obtained using large volume scintillation detectors at the different depths (25 m.w.e.,316 m. w.e.,570 m.w.e.,3300 m.w.e.and 5200 m.w.e.) are presented.The characteristics of the hadron fluxes and other secondaries underground are reported.Problems of different source neutrino detection in cosmic rays are discussed.

Ryazhskaya, O. G.

1996-05-01

42

Detection of elusive radio and optical emission from cosmic-ray showers in the 1960s  

NASA Astrophysics Data System (ADS)

During the 1960s, a small but vibrant community of cosmic ray physicists, pioneered novel optical methods of detecting extensive air showers (EAS) in the Earth's atmosphere with the prime objective of searching for point sources of energetic cosmic ?-rays. Throughout that decade, progress was extremely slow. Attempts to use the emission of optical Cherenkov [1] radiation from showers as a basis for TeV gamma-ray astronomy proved difficult and problematical, given the rather primitive light-collecting systems in use at the time, coupled with a practical inability to reject the overwhelming background arising from hadronic showers. Simultaneously, a number of groups experimented with passive detection of radio emission from EAS as a possible cheap, simple, stand-alone method to detect and characterise showers of energy greater than 1016 eV. By the end of the decade, it was shown that the radio emission was quite highly beamed and hence the effective collection area for detection of high energy showers was quite limited, diminishing the effectiveness of the radio signature as a stand-alone shower detection channel. By the early 1970s much of the early optimism for both the optical and radio techniques was beginning to dissipate, greatly reducing research activity. However, following a long hiatus both avenues were in time revived, the optical in the early 1980s and the radio in the early 2000s. With the advent of digital logic hardware, powerful low-cost computing, the ability to perform Monte Carlo simulations and above all, greatly improved funding, rapid progress became possible. In time this work proved to be fundamental to both High Energy ?-ray Astronomy and Neutrino Astrophysics. Here, that first decade of experimental investigation in both fields is reviewed.

Fegan, David J.

2012-01-01

43

Effects of atmospheric electric fields on detection of ultrahigh-energy cosmic rays  

SciTech Connect

We show that atmospheric electric fields may affect the cosmic ray observations in several ways and may lead to an overestimation of the cosmic ray energies. The electric field in thunderclouds can be as high as a few kV/cm. This field can accelerate the shower electrons and can feed some additional energy into the shower. Therefore, ground array observations in certain weather conditions may overestimate the energy of ultrahigh-energy cosmic rays if they do not take this effect into account. In addition, the electric field can bend the muon trajectories and affect the direction and energy reconstruction of inclined showers. Finally, there is a possibility of an avalanche multiplication of the shower electrons due to a runaway breakdown, which may lead to a significant miscalculation of the cosmic ray energy.

Kusenko, Alexander [Department of Physics and Astronomy, UCLA, Los Angeles, California 90095-1547 (United States); Semikoz, Dmitry [Department of Physics and Astronomy, UCLA, Los Angeles, California 90095-1547 (United States); Institute for Nuclear Research RAS, 60th October Anniversary prospect 7a, 117312 Moscow (Russian Federation)

2004-12-15

44

Large doppler shift in radar detection of ultra-high energy cosmic rays.  

SciTech Connect

Radar detection of cosmic ray air showers has been discussed for 60 years, but never clearly observed. The topic was reexamined by Gorham in 2001 and some serious simulations were done by Takai, who also initiated the Mariachi project utilizing commercial television transmissions as a signal source. The air showers from ultra-high energy cosmic rays are expected to generate a plasma with plasma frequency in the high VHF region. One factor limiting the received signal strength is the short ion recombination time in air at low altitude. However, a major factor which has not been the center of attention so far is the possible large Doppler shifts for non-specular reflection, and the soft transition between specular and diffuse for small objects and short time scales. We discuss recent work on receivers, and simulations of the Doppler shift. These simulations assume a very short ion recombination time in the lower atmosphere, and use an extremely simple mathematical model. A central feature of our simulations is large Doppler shift from non-moving material.

Underwood, D. G.; High Energy Physics

2008-01-01

45

Relativistic effects in radar detection of ionization fronts produced by ultra-high energy cosmic rays  

NASA Astrophysics Data System (ADS)

We revisit the radar echo technique as an approach to detect ultra-high energy cosmic rays (UHECR). The UHECR extensive air showers generate disk-like ionization fronts propagating with a relativistic velocity and creating fast decaying plasma. We study the reflection of a radio wave, such as the one from a radar transmitter or commercial radio and TV station, from the relativistic ionization front. The reflected wave will be frequency upshifted due to the relativistic Doppler effect and propagate almost normally to the front due to relativistic aberration. The amplitude of the reflected wave depends strongly on the front velocity and parameters (density, collision frequency) of the plasma behind the front. We develop a theory that allows one to find the reflected wave. Using this theory and typical parameters of extensive air showers, we discuss the feasibility of UHECR detection.

Bakunov, M. I.; Maslov, A. V.; Novokovskaya, A. L.; Kryemadhi, A.

2010-06-01

46

Introduction to Cosmic Rays  

Microsoft Academic Search

Energetic particles, traditionally called Cosmic Rays, were discovered nearly a hundred years ago, and their origin is still uncertain. Their main constituents are the normal\\u000a nuclei as in the standard cosmic abundances of matter, with some enhancements for the heavier elements; there are also electrons,\\u000a positrons and antiprotons. Today we also have information on isotopic abundances, which show some anomalies,

Peter L. Biermann; Guenter Sigl

2001-01-01

47

Cosmic Ray Dosimetry  

NASA Astrophysics Data System (ADS)

Radiation levels at aircraft cruising altitudes are twenty times higher than at sea level. Thus, on average, a typical airline pilot receives a larger annual radiation dose than some one working in nuclear industry. The main source of this radiation is from galactic cosmic radiation, high energy particles generated by exploding stars within our own galaxy. In this work we study cosmic rays dosimetry at various aviation altitudes using the PARMA model.

Si Belkhir, F.; Attallah, R.

2010-10-01

48

Scintillator Cosmic Ray Super Telescope  

NASA Astrophysics Data System (ADS)

The Scintillator Cosmic Ray Super Telescope (SciCRST) is a new experiment to detect solar neutrons, and also it is expected to work as a muon and cosmic ray detector. The SciCRST consist of 14,848 plastic scintillator bars, and it will be installed at the top of Sierra Negra volcano, Mexico, 4580 m.a.s.l. We use a prototype, called as miniSciBar, to test the hardware and software of the final experiment. In this paper, we present the status and details of the experiment, and results of the prototype.

González, L. X.; Valdés-Galicia, J. F.; Matsubara, Y.; Nagai, Y.; Itow, Y.; Sako, T.; López, D.; Mitsuka, G.; Munakata, K.; Kato, C.; Yasue, S.; Kosai, M.; Tsurusashi, M.; Nakamo, Y.; Shibata, S.; Takamaru, H.; Kojima, H.; Tsuchiya, H.; Watanabe, K.; Koi, T.; Fragoso, E.; Hurtado, A.; Musalem, O.

2013-04-01

49

A cocoon of freshly accelerated cosmic rays detected by Fermi in the Cygnus superbubble  

NASA Astrophysics Data System (ADS)

Conspicuous stellar clusters, with high densities of massive stars, powerful stellar winds, and intense UV flux, have formed over the past few million years in the large molecular clouds of the Cygnus X region, 1.4 kpc away from the Sun. By capturing the gamma-ray signal of young cosmic rays spreading in the interstellar medium surrounding the clusters, the Fermi Large Area Telescope (LAT) has confirmed the long-standing hypothesis that massive-star forming regions host cosmic-ray factories. The 50-pc wide cocoon of energetic particles appears to fill the interstellar cavities carved by the stellar activity. The cocoon provides a first test case to study the impact of wind-powered turbulence on the early phases of cosmic-ray diffusion (between the sources and the Galaxy at large) and to study the acceleration potential of this type of superbubble environment for in-situ cosmic-ray production or to energize Galactic cosmic rays passing by.

Grenier, Isabelle A.; Tibaldo, Luigi; Fermi-LAT Collaboration

2013-02-01

50

Radio emission from extensive air showers as a method for cosmic-ray detection  

SciTech Connect

At the present time, radio emission from extensive air showers (EASs) is being considered as a new promising method for detecting cosmic rays of energy in the region E{sub 0} > 5 x 10{sup 16} eV. Radio emission from an EAS whose development is simulated by the Monte Carlo method is calculated here. The field of radio emission from an EAS is calculated on the basis of two representations of a shower: that as a set of individual particles and that as a continuous set of currents. The sensitivity of radio emission to EAS parameters in the frequency range 10-100 MHz is investigated. The results can be used to analyze experiments that being presently performed (CODALEMA and LOPES) and those that are being planned for the future.

Kalmykov, N. N.; Konstantinov, A. A., E-mail: elan1980@mail.r [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation); Engel, R. [Karlsruhe Institute of Technology (Germany)

2010-07-15

51

Detection of ultrahigh-energy cosmic rays and neutrinos by a lunar nanosatellite-borne radio receiver  

NASA Astrophysics Data System (ADS)

The feasibility of ultrahigh-energy cosmic ray and neutrino detection by a lunar nanosatellite-borne radio receiver is discussed. The estimated values of the energy threshold and event rate for cosmic ray detection are found to be Eth(CR) ? 1018 eV, N(CR, E ? 1019 eV) ? a few hundreds of events per day, and N(CR, E ? 1020 eV) is more than thousand events per year. Cosmic -ray particle energy and arrival angles will be measured. Thus, the proposed experiment will have very high scientific potential in detection of ultrahigh-energy cosmic rays comparable to that of the most ambitious proposals like EUSO and OWL, the cost being one or two orders of magnitude lower. Moreover, neutrinos with E > Eth(neutrino) ? 5\\cdot 1018 eV can be also detected in the same experiment at the rate of a few to a few hundreds of events per year depending on the neutrino-source model. The basic design of the antenna system and concept of the registration channel are presented.

Chechin, V. A.; Lomonosov, B. N.; Pichkhadze, K. M.; Poluhina, N. G.; Ryabov, V. A.; Sysoev, V. K.; Tsarev, V. A.

52

In Search of Cosmic Rays  

NSDL National Science Digital Library

The authors discuss the Cosmic Ray Observatory Project (CROP), focusing on their high school's participation in the project. Students build and monitor cosmic ray detectors to count and study cosmic rays and to determine whether or not the time of day inf

Streich, Derek; Antonelli, Jamie; Liebl, Michael; Mahoney, Sean

2001-11-01

53

Galactic cosmic rays and nucleosynthesis  

SciTech Connect

The nucleosynthesis of the light elements Li, Be and B by galactic cosmic rays is presented. Observations of cosmic rays and the nuclear reactions responsible for Li, Be and B nucleosynthesis are described, followed by some words on propagation. At the end, some open questions concerning galactic cosmic rays are discussed.

Kiener, Juergen [CSNSM, CNRS-IN2P3 and Universite Paris-Sud, Bat. 104-108, 91405 Orsay Campus (France)

2010-03-01

54

Cosmic Ray Studies of Antimatter  

Microsoft Academic Search

Forty years after the discovery of the antiproton the study of cosmic-ray antimatter continues to be an exciting and fertile field. Sensitive searches for heavy cosmic-ray antimatter continue, although in recent years their value as a probe of universal baryon symmetry has all but evaporated. Antiprotons and positrons have opened new windows on the origin and history of cosmic rays.

Gregory Tarlé

1996-01-01

55

Atmospheric Cosmic Ray Detectors  

NASA Astrophysics Data System (ADS)

This document is part of Part 2 'Principles and Methods' of Subvolume B 'Detectors for Particles and Radiation' of Volume 21 'Elementary Particles' of Landolt-Börnstein - Group I 'Elementary Particles, Nuclei and Atoms'. It contains the Section '6.1 Atmospheric Cosmic Ray Detectors' of Chapter '6 Detectors for Special Applications' with the content:

Blümer, J.; Engler, J.

56

Improvements of an x-ray microcalorimeter for detecting cosmic rays  

NASA Astrophysics Data System (ADS)

An X-ray microcalorimeter that consists of an x-ray absorber to transfer the incident photon energy to the temperature rise, a temperature sensor to detect the temperature change and suspending beams for thermal isolation from the substrate have been fabricated. Titanium/Gold thin film transition edge sensor (TES) is used as the temperature sensor. We fabricated and tested the first prototype in the previous study and obtained the transition temperature of 0.52 K, energy resolution of 550 eV (FWHM) for 6 keV radiation. These values were smaller than that of expected. We applied a Sn absorber and redesigned the microstructure of the x-ray microcalorimeter. Consequently, we have obtained 158 eV at 5.9 keV radiation of the energy resolution, which is about 4 times higher than that of the first prototype. This value is nearly equal to the conventional X-ray CCD. The highest energy resolution of the x-ray microcalorimeter of our design is estimated to approximately 5 eV at the operating point of 0.2 K. To realize such a good energy resolution calorimeter array, we are going to improve the sensitivity of the TES by optimizing the process condition. A Sn absorber formed by electroplating is also under evaluating simultaneously. It is necessary to fabricate uniform array structures.

Yokoyama, Yuichi; Shoji, Shuichi; Mitsuda, Kazuhisa; Fujimoto, Ryuichi; Miyazaki, Toshiyuki; Oshima, Tohru; Yamazaki, Masahiro; Iyomoto, Naoko; Futamoto, Kazuo; Ishizaki, Yoshinao; Kagei, Tomohiro

2000-10-01

57

The cosmic triad: Cosmic rays, gamma-rays and neutrinos  

NASA Astrophysics Data System (ADS)

The existence of ultra-high energy (UHE) cosmic rays (CRs) with energies up to 100 EeV is a strong motivation for neutrino astronomy at the EeV energy scale. It seems unavoidable that UHE CRs undergo hadronic interactions with radiation backgrounds and ambient matter prior to their arrival at Earth. These interactions result in a flux of secondary neutrinos and ?-rays with energies up to a few percent of the initial CR energy. So far, no high-energy neutrino source could be unambiguously identified. We will review the various indirect neutrino limits that arise from the cosmic connection of UHE CRs, ?-rays and neutrinos. At the EeV energy scale the diffuse flux of cosmogenic neutrinos associated with the propagation of ultra-high energy cosmic rays in the cosmic radiation background seems to be the most promising candidate for a future detection. We will discuss its model dependence w.r.t. nuclear composition and evolution of the sources.

Ahlers, Markus

2013-05-01

58

Search for cosmic ray sources using muons detected by the MACRO experiment  

Microsoft Academic Search

The MACRO underground detector at Gran Sasso Laboratory recorded 60 million secondary cosmic ray muons from February 1989 until December 2000. Different techniques were used to analyze this sample in search for density excesses from astrophysical point-like sources. No evidence for DC excesses for any source in an all-sky survey is reported. In addition, searches for muon excess correlated with

M. Ambrosio; R. Antolini; G. Auriemma; D. Bakari; A. Baldini; G. C. Barbarino; B. C. Barish; G. Battistoni; Y. Becherini; R. Bellotti; C. Bemporad; P. Bernardini; H. Bilokon; C. Bloise; C. Bower; M. Brigida; S. Bussino; F. Cafagna; M. Calicchio; D. Campana; M. Carboni; R. Caruso; S. Cecchini; F. Cei; V. Chiarella; B. C. Choudhary; S. Coutu; M. Cozzi; G. De Cataldo; H. Dekhissi; C. De Marzo; I. De Mitri; J. Derkaoui; M. De Vincenzi; A. Di Credico; O. Erriquez; C. Favuzzi; C. Forti; P. Fusco; G. Giacomelli; G. Giannini; N. Giglietto; M. Giorgini; M. Grassi; A. Grillo; F. Guarino; C. Gustavino; A. Habig; K. Hanson; R. Heinz; E. Iarocci; E. Katsavounidis; I. Katsavounidis; E. Kearns; H. Kim; S. Kyriazopoulou; E. Lamanna; D. S. Levin; P. Lipari; N. P. Longley; M. J. Longo; F. Loparco; F. Maaroufi; G. Mancarella; G. Mandrioli; A. Margiotta; A. Marini; D. Martello; A. Marzari-Chiesa; M. N. Mazziotta; D. G. Michael; P. Monacelli; T. Montaruli; M. Monteno; S. Mufson; J. Musser; D. Nicolò; R. Nolty; C. Orth; G. Osteria; O. Palamara; V. Patera; L. Patrizii; R. Pazzi; C. W. Peck; L. Perrone; S. Petrera; P. Pistilli; V. Popa; A. Rainò; J. Reynoldson; F. Ronga; A. Rrhioua; C. Satriano; E. Scapparone; K. Scholberg; A. Sciubba; P. Serra; M. Sioli; G. Sirri; M. Sitta; P. Spinelli; M. Spinetti; M. Spurio; R. Steinberg; J. L. Stone; L. R. Sulak; A. Surdo; G. Tarlè; V. Togo; M. Vakili; C. W. Walter; R. Webb

2003-01-01

59

Cosmic Rays: "A Thin Rain of Charged Particles."  

ERIC Educational Resources Information Center

|Discussed are balloons and electroscopes, understanding cosmic rays, cosmic ray paths, isotopes and cosmic-ray travel, sources of cosmic rays, and accelerating cosmic rays. Some of the history of the discovery and study of cosmic rays is presented. (CW)|

Friedlander, Michael

1990-01-01

60

A balloon-borne instrumentation for cosmic gamma-ray burst detection and measurement  

Microsoft Academic Search

A wide-field X-ray detector for observations of cosmic gamma-ray bursts has been prepared and launched on a balloon platform from the base of Trapani-Milo (Sicily) in July of 1983. The detector is an imaging type, 40 cm diameter gamma camera, paired with a 1.8 m diameter pseudorandom, 50% open mask, to make up the telescope. The detector works in the

G. Ventura; H. M. Horstman; A. Brighenti; C. Cavani; M. Camprini; P. Cazzola; G. Giovannini; C. Labanti; J. M. Poulsen

1984-01-01

61

Cosmic Ray research in Armenia  

NASA Astrophysics Data System (ADS)

Cosmic Ray research on Mt. Aragats began in 1934 with the measurements of East-West anisotropy by the group from Leningrad Physics-Technical Institute and Norair Kocharian from Yerevan State University. Stimulated by the results of their experiments in 1942 Artem and Abraham Alikhanyan brothers organized a scientific expedition to Aragats. Since that time physicists were studying Cosmic Ray fluxes on Mt. Aragats with various particle detectors: mass spectrometers, calorimeters, transition radiation detectors, and huge particle detector arrays detecting protons and nuclei accelerated in most violent explosions in Galaxy. Latest activities at Mt. Aragats include Space Weather research with networks of particle detectors located in Armenia and abroad, and detectors of Space Education center in Yerevan.

Chilingarian, A.; Mirzoyan, R.; Zazyan, M.

2009-11-01

62

The Microwave Air Yield Beam Experiment (MAYBE): measurement of GHz radiation for Ultra-High Energy Cosmic Rays detection  

NASA Astrophysics Data System (ADS)

We present measurements of microwave emission from an electron beam induced air plasma, performed at the electron Van de Graaff facility of the Argonne National Laboratory. Radio emission is studied over a wide range of frequencies between 1 and 15 GHz. This measurement provides further insight on microwave emission from extensive air showers as a novel detection technique for Ultra-High Energy Cosmic Rays.

Williams, Christopher; Bohacova, Martina; Bonifazi, Carla; Cataldi, Gabriella; Chemerisov, Sergey; de Mello Neto, Joao; Facal San Luis, Pedro; Fox, Brendan; Gorham, Peter W.; Hojvat, Carlos; Hollon, Nick; Meyhandan, Rishi; Reyes, Luis; Rouille D'Orfeuil, Benjamin; Santos, Edivaldo M.; Pochez, James; Privitera, Paolo; Spinka, Hal; Verzi, Valerio; Monasor, Maria; Zhou, Jing

2012-03-01

63

The AMY experiment to measure GHz radiation for Ultra-High Energy Cosmic Ray detection  

NASA Astrophysics Data System (ADS)

The Air Microwave Yield (AMY) project aims to measure the emission in the GHz regime from test-beam induced air-shower. The experiment is using the Beam Test Facility (BTF) of the Frascati INFN National Laboratories in Italy. The final purpose is to characterize a process to be used in a next generation of ultra-high energy cosmic rays (UHECRs) detectors. We describe the experimental apparatus and the first test performed in November 2011.

Alvarez-Muniz, J.; Bohacova, M.; Cataldi, G.; Coluccia, M. R.; Creti, P.; De Mitri, I.; Di Giulio, C.; Engel, R.; Facal San Luis, P.; Iarlori, M.; Martello, D.; Monasor, M.; Perrone, L.; Petrera, S.; Privitera, P.; Riegel, M.; Rizi, V.; Rodriguez Fernandez, G.; Salamida, F.; Salina, G.; Settimo, M.; Smida, R.; Verzi, V.; Werner, F.; Williams, C.

2013-02-01

64

Indirect dark matter detection with cosmic antimatter  

Microsoft Academic Search

The indirect detection of particle dark matter (DM) is based on the search for anomalous components in cosmic rays (CRs) due to the annihilation of DM pairs in the galactic halo, on the top of the standard astrophysical production. These additional exotic components are potentially detectable at Earth as spectral distortions for the various cosmic radiations: $\\\\chi + \\\\chi \\\\to

Pierre Salati; Fiorenza Donato; Nicolao Fornengo

2010-01-01

65

Dark Matter Content in Q-Cosmology and Its Detectability in Anisotropy of Cosmic Gamma-Ray Spectra  

NASA Astrophysics Data System (ADS)

Dissipative Liouville cosmology (Q-Cosmology) introduces the effect of the dilaton field and central charge deficit on relic density of cold dark matter (CDM). The result is a reduction factor of 10 of the relic density, as compared to the value obtained in ordinary cosmology (Lahanas et al, 2007). Since dark matter particles are weakly interacting, annihilation can only occur in regions with high density, such as dark matter halos. Previous works on the anisotropy of the cosmic gamma-ray background (CGB) have shown that dark matter annihilation can be separated from the known background in the anisotropy data (Endo, Komatsu, 2007). In this talk, we first explain the dark matter content of the universe in Q-Cosmology and then study the detectability of this new model in the anisotropy of the cosmic gammy-ray spectra.

Truong, Phuongmai; Dutta, Bhaskar; Campbell, Sheldon; Krislock, Abram

2007-10-01

66

The Origin of Cosmic Rays  

Microsoft Academic Search

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

Blasi; Pasquale

2008-01-01

67

Forbush decreases in cosmic rays  

Microsoft Academic Search

The cosmic-ray time variation called Forbush decreases are examined in an overview of observational data with attention given to the three species of Forbush decreases. References are made to the satellite observations of magnetic fields associated with Forbush decreases and of the interactions between interplanetary shock and coronal ejection. The 27-day variations of cosmic rays are discussed in terms of

D. Venkatesan; A. G. Ananth

1991-01-01

68

Cosmic Ray Neutron Flux Measurements  

NASA Astrophysics Data System (ADS)

Cosmic rays are high-energetic particles originating from outer space that bombard the upper atmosphere of the Earth. Almost 90% of cosmic ray particles consist of protons, electrons and heavy ions. When these particles hit the Earth's atmosphere, cascade of secondary particles are formed. The most abundant particles reach to the surface of the Earth are muons, electrons and neutrons. In recent years many research groups are looking into potential applications of the effects of cosmic ray radiation at the surface of the Earth [1, 2]. At Georgia State University we are working on a long-term measurement of cosmic ray flux distribution. This study includes the simultaneous measurement of cosmic ray muons, neutrons and gamma particles at the Earth surface in downtown Atlanta. The initial effort is focusing on the correlation studies of the cosmic ray particle flux distribution and the atmospheric weather conditions. In this presentation, I will talk about the development of a cosmic ray detector using liquid scintillator and the preliminary results. [4pt] [1] K.Borozdin, G.Hogan, C.Morris, W.Priedhorsky, A.Saunders, L.Shultz, M.Teasdale, ``Radiographic imaging with cosmic-ray muons'', Nature, Vol.422, p.277, Mar.2003[0pt] [2] Svensmark Henrik, Physical Review 81, 3, (1998)

Dayananda, Mathes

2009-11-01

69

Acceleration et propagation des rayons cosmiques. Production, oscillations et detection de neutrinos. (Acceleration and propagation of cosmic rays. Production, oscillation and detection of neutrinos).  

National Technical Information Service (NTIS)

This thesis is devoted to studies on cosmic rays and neutrinos, particles astrophysically relevant. In recent years, the old problem of cosmic-ray acceleration and propagation has become alive again, with the discovery of the diffusive shock acceleration ...

P. O. Lagage

1987-01-01

70

Cosmic-Rays and Gamma Ray Bursts  

NASA Astrophysics Data System (ADS)

Cosmic-rays are subatomic particles of energies ranging between a few eV to hundreds of TeV. These particles register a power-law spectrum, and it seems that most of them originate from astrophysical galactic and extragalactic sources. The shock acceleration in superalfvenic astrophysical plasmas, is believed to be the main mechanism responsible for the production of the non-thermal cosmic-rays. Especially, the importance of the very high energy cosmic-ray acceleration, with its consequent gamma-ray radiation and neutrino production in the shocks of the relativistic jets of Gamma Ray Bursts, is a favourable theme of study. I will discuss the cosmic-ray shock acceleration mechanism particularly focusing on simulation studies of cosmic-ray acceleration occurring in the relativistic shocks of GRB jets.

Meli, A.

2013-07-01

71

Exploring design tradeoffs of a distributed algorithm for cosmic ray event detection  

NASA Astrophysics Data System (ADS)

Many sensor networks, including large particle detector arrays measuring high-energy cosmic-ray air showers, traditionally rely on centralised trigger algorithms to find spatial and temporal coincidences of individual nodes. Such schemes suffer from scalability problems, especially if the nodes communicate wirelessly or have bandwidth limitations. However, nodes which instead communicate with each other can, in principle, use a distributed algorithm to find coincident events themselves without communication with a central node. We present such an algorithm and consider various design tradeoffs involved, in the context of a potential trigger for the Auger Engineering Radio Array (AERA).

Yousaf, S.; Bakhshi, R.; van Steen, M.; Voulgaris, S.; Kelley, J. L.

2013-03-01

72

High energy neutrinos from astrophysical accelerators of cosmic ray nuclei  

Microsoft Academic Search

Ongoing experimental efforts to detect cosmic sources of high energy neutrinos are guided by the expectation that astrophysical accelerators of cosmic ray protons would also generate neutrinos through interactions with ambient matter and\\/or photons. However, there will be a reduction in the predicted neutrino flux if cosmic ray sources accelerate not only protons but also significant numbers of heavier nuclei,

Luis A. Anchordoqui; Dan Hooper; Subir Sarkar; Andrew M. Taylor

2008-01-01

73

A Correlation Between the Highest Energy Cosmic Rays and Nearby Active Galactic Nuclei Detected by Fermi  

NASA Astrophysics Data System (ADS)

We analyze the correlation of the positions of ?-ray sources in the Fermi Large Area Telescope (LAT) First Source Catalog (1FGL) and the First LAT Active Galactic Nuclei (AGNs) Catalog (1LAC) with the arrival directions of ultra-high-energy cosmic rays (UHECRs) observed with the Pierre Auger Observatory, in order to investigate the origin of UHECRs. We find that Galactic sources and blazars identified in the 1FGL are not significantly correlated with UHECRs, while the 1LAC sources display a mild correlation (2.6? level) on an ?2fdg4 angular scale. When selecting only the 1LAC AGNs closer than 200 Mpc, we find a strong association (5.4?) between their positions and the directions of UHECRs on an ?17° angular scale; the probability of the observed configuration being due to an isotropic flux of cosmic rays is 5 × 10-8. There is also a 5? correlation with nearby 1LAC sources on a 6fdg5 scale. We identify seven "?-ray loud" AGNs which are associated with UHECRs within ?17° and are likely candidates for the production sites of UHECRs: Centaurus A, NGC 4945, ESO 323-G77, 4C+04.77, NGC 1218, RX J0008.0+1450, and NGC 253. We interpret these results as providing additional support to the hypothesis of the origin of UHECRs in nearby extragalactic objects. As the angular scales of the correlations are large, we discuss the possibility that intervening magnetic fields might be considerably deflecting the trajectories of the particles on their way to Earth.

Nemmen, Rodrigo S.; Bonatto, Charles; Storchi-Bergmann, Thaisa

2010-10-01

74

The Origin of Cosmic Rays  

Microsoft Academic Search

The isotropy and composition of the primary cosmic radiation suggest that cosmic rays are trapped within the galaxy for an average time of the order of 106 years,-a long time compared with the time of escape along straight-line paths, but short compared with the mean life against nuclear collisions with interstellar matter. If one accepts this conclusion, it appears possible

Philip Morrison; Stanislaw Olbert; Bruno Rossi

1954-01-01

75

Fast time correlation detection in associated particle spectrometry of spontaneous fission neutrons and cosmic-ray backgrounds  

NASA Astrophysics Data System (ADS)

We have investigated neutron spectrometry using fast gamma-ray detectors (BaF2) in coincidence with a gamma/neutron detector (plastic scintillator). Neutron spectra of spontaneous fission sources are determined by time-of-flight between correlated gamma and neutron detections using the associated particle (AP) technique. When the source is within a ~1 meter zone of detector separation, the correlated neutron detection efficiency is high because of the multiplicity of gamma-rays (10 gammas/fission in 252Cf) and neutrons (3.6 neutrons/fission). Cosmic-ray produced neutron detection efficiency is quite low in an AP measurement using a <50ns coincidence window because time-of-flight of most events is long from its creation within the 120 meters e-folding neutron range of air. We found that the AP signal to background ratio was dominated by uncorrelated coincidences and propose a triple coincidence system (1 neutron and 2 gamma-ray detectors) to improve performance. The gamma/gamma-ray coincidence time distribution is related to the target's production history where fast neutron multiplication may be a dominant physical process. MCNPX calculations suggest that the gamma-ray time history of Depleted Uranium (DU) and Highly Enriched Uranium (HEU) provide separable signatures because fast neutron multiplication is much higher in HEU.

Forman, Leon; Dioszegi, Istvan; Vanier, Peter E.

2010-08-01

76

The ANITA experiment: new high-energy neutrino limits and detection of ultra-high energy cosmic rays  

NASA Astrophysics Data System (ADS)

The ANITA (ANtarctic Impulsive Transient Antenna) instrument is a balloon-borne telescope designed to detect coherent radio Cherenkov emission in the frequency range of 200-1200 MHz from showers produced in the Antarctic ice by interaction of cosmogenic ultra-high energy neu-trinos with energy greater than about 3 x 1018 eV. We will discuss results from the second flight (ANITA-II), which was launched in December 2008 from Antarctica and included signif-icant improvements in sensitivity and efficiency for neutrino detection over that of ANITA-I, which was launched in December 2006. Additionally, the balloon trajectory of ANITA-II gave substantially more time over deep ice than that of ANITA-I. We will present upper limits on neutrinos that constrain models of neutrino origin. In addition, we have 16 events detected in the ANITA-I flight with strong evidence of their origin as geosynchrotron radio emission reflecting off of the Antarctic snow from ultra-high-energy (of order 1019 eV) cosmic-ray air showers. The increasing aperture of this technique with energy allows us to set limits on the presence of cosmic rays with energies beyond 1020 eV.

Binns, Walter; Gorham, P. W.; Allison, P.; Baughmann, B.; Beatty, J. J.; Belov, K.; Besson, D. Z.; Bevan, S.; Binns, W. R.; Chen, C.; Chen, P.; Clem, J. M.; Connolly, A.; Detrixhe, M.; Demarco, D.; Dowkontt, P. F.; Goodhue-Vieregg, A.; Grashorn, E.; Hill, N. Griffith. B.; Hoover, S.; Israel, M. H.; Javaid, A.; Liewer, K. M.; Matsuno, S.; Mercurio, B. C.; Miki, C.; Mottram, M.; Nam, J.; Nichol, R. J.; Palladino, K.; Romero-Wolf, A.; Ruckman, L.; Saltzberg, D.; Seckel, D.; Varner, G. S.; Wang, Y.

77

Cosmic rays: 1912-2012  

NASA Astrophysics Data System (ADS)

One hundred years ago, using balloon flights up to 5 kilometers altitude, Victor Hess demonstrated that the intensity of penetrating ionizing radiation increased with altitude, indicating that Earth is exposed to high-energy radiation from space [Hess, 1912]. Since that observation, these “cosmic rays” have enabled discoveries basic to elementary particle physics and astrophysics. This discovery earned Hess the 1936 Nobel Prize in Physics, shared with Carl Anderson, who discovered the positron among the secondary cosmic rays near the ground [Anderson, 1933]. Then, the only known ionizing radiation with range in air more than about 30 centimeters was the ? ray (electromagnetic radiation with energy above about 100 kiloelectron volts), so the radiation from space was assumed to be ? rays and was called “cosmic rays.” That name has stuck, although the “cosmic rays” studied today are not actually rays but particles. Indeed, ? rays do impinge on Earth, and ? ray astronomy is a burgeoning area of astrophysics, but the term “cosmic rays” continues to apply to the charged particles that make up the bulk of the incident ionizing radiation.

Israel, Martin H.

2012-09-01

78

The Highest Energy Cosmic Rays  

NASA Astrophysics Data System (ADS)

I refuse to start yet another abstract saying that the origin of cosmic rays is a mystery. Instead, I would like to highlight the progress made by ultra-high energy cosmic ray experiments in the last three years. The Pierre Auger Observatory and the Telescope Array are the largest cosmic ray detectors ever built, and together they cover the entire sky at the highest energies. I will present the most recent experimental results, and discuss their implications toward an understanding of the origin of Extragalactic cosmic rays. Finding the transition between Galactic and Extragalactic origin is an important step forward because it will allow us to concentrate our searches on specific energy ranges and specific objects in the sky.

Mostafa, Miguel

2012-03-01

79

A cosmic ray propagation model  

NASA Astrophysics Data System (ADS)

This work describes a stepwise program of interstellar cosmic ray propagation that is used to study the sensitivity of propagation models of ultra heavy cosmic ray nuclei (UH nuclei). We have evaluated the uncertainties introduced in the predicted abundances by calculating the fragmentation cross sections using different procedures, by varying the input energy, and by varying the escape length of the cosmic ray nuclei. These uncertainties have been compared with the predicted differences introduced by assuming that the source abundances resemble either solar system, pure r-, or pure s-process material. These comparisons allow us to determine how the uncertainties in the above mentioned parameters affect the abundances of the cosmic ray nuclei. We conclude that the uncertainties in nuclear cross sections presently prevent us from drawing any but the broadest conclusions from the measured abundances.

Clinton, Robert Russell

80

School Cosmic Ray Outreach Detector (SCROD)  

NASA Astrophysics Data System (ADS)

We report on our studies of applying novel detector technologies developed for LHC-era experiments to cosmic ray detection. In particular, we are investigating usage of scintillating tiles with embedded wavelength-shifting fibers and avalanche photodiode readout as part of a robust, inexpensive cosmic air shower detector. In the near future, we are planning to deploy detector stations based on this technology at area high schools and colleges as part of an outreach and education effort, known as SCROD.

Anchordoqui, L.; Cook, J.; MacLeod, J.; McCauley, T.; Moussienko, I.; Paul, T.; Reucroft, S.; Swain, J.; Terry, R.

81

Cosmic-Ray Underground. I  

Microsoft Academic Search

Behaviour of elementary particles in the cosmic-ray in moderate high energy region can be infered by the analysis of cosmic-ray phenomena underground, but few such attempts have ever been made and all of them have failed in giving a satisfactory understanding of the problem. Several years ago one of us (S.T.) tried without success to explain the remarkable bend of

Satio Hayakawa; Sin-Itiro Tomonaga

1949-01-01

82

Cosmic-Ray-Induced Radioactivity in Terrestrial Materials  

Microsoft Academic Search

Cosmic-ray-induced activities have been detected in a few laboratory materials both at sea level and at mountain altitude. The measured amounts are found to be consistent with those expected to be produced from known flux of cosmic-ray neutrons and negative muons. Introduction. While passing through the earth's atmosphere cosmic rays interact with air nuclei and produce easily detectable quantities of

RAMAAND MASATAKE HONDA

1961-01-01

83

Primary cosmic ray mass composition seen through gamma rays detected by passive balloon-borne emulsion chambers  

Microsoft Academic Search

The gamma rays detected by passive balloon-borne emulsion chambers in the stratosphere allow indirect testing of the conclusions based on the analysis of the primary particle tracks. Here we show that observed experimental data on gamma rays are in agreement with the atmospheric origin of their production. It can be seen that gamma rays from different passive balloon-borne experiments are

V. KOPENKIN

84

Astrophysics of Galactic Charged Cosmic Rays  

NASA Astrophysics Data System (ADS)

A review is given of the main properties of the charged component of galactic cosmic rays, particles detected at Earth with an energy spanning from tens of MeV up to about 1019 eV. After a short introduction to the topic and a historical overview, the properties of cosmic rays are discussed with respect to different energy ranges. The origin and the propagation of nuclei in the Galaxy are dealt with from a theoretical point of view. The mechanisms leading to the acceleration of nuclei by supernova remnants and to their subsequent diffusion through the inhomogeneities of the galactic magnetic field are discussed, and some clue is given on the predictions and observations of fluxes of antimatter, both from astrophysical sources and from dark matter annihilation in the galactic halo.The experimental techniques and instrumentations employed for the detection of cosmic rays at Earth are described. Direct methods are viable up to ? 1014 eV, by means of experiments flown on balloons or satellites, while above that energy, due to their very low flux, cosmic rays can be studied only indirectly by exploiting the particle cascades they produce in the atmosphere.The possible physical interpretation of the peculiar features observed in the energy spectrum of galactic cosmic rays, and in particular the so-called "knee" at about 4 ×1015 eV, is discussed. A section is devoted to the region between about 1018 and 1019 eV, which is believed to host the transition between galactic and extragalactic cosmic rays. The conclusion gives some perspectives on the cosmic ray astrophysics field. Thanks to a wealth of different experiments, this research area is living a very flourishing era. The activity is exciting both from the theoretical and the instrumental sides, and its interconnection with astronomy, astrophysics, and particle physics experiences nonstop growth.

Castellina, Antonella; Donato, Fiorenza

85

Cosmic Ray Identification and Ramp-fitting in JWST Data  

NASA Astrophysics Data System (ADS)

Cosmic rays are expected to significantly affect on-orbit JWST detectors as the cosmic-ray environment does not benefit from shielding by the Earth's magnetic field. Data is read non-destructively (up-the-ramp) so cosmic rays can be recognized as jumps in the pixel ramps as signal accumulates. Because the effect of a cosmic ray is to add a large and unpredictable number of counts to the signal, it is important to correctly flag cosmic rays to enable valid count rates to be calculated for science pixel data. Once the cosmic rays are identified, a fit can be performed for the data between cosmic ray-affected reads, allowing the count rate for each pixel to be estimated. In lieu of having on-orbit data on which to test cosmic ray rejection algorithms and fitting algorithms, a set of Python scripts was written to generate artificial datasets that include realistic celestial sources and cosmic rays. An investigation was made into ways of detecting cosmic rays, and then how to measure the underlying count rate signal in the presence of these jumps. As the on-orbit datasets will be large, techniques to reduce the processing time by reducing the memory requirements and reordering the data have been investigated. Cosmic ray rejection and ramp fitting will be incorporated into the JWST Calibration pipeline to reduce on-orbit data.

Grumm, D.; Greenfield, P.

2012-09-01

86

Investigation of primary cosmic rays at the Moon's surface  

NASA Astrophysics Data System (ADS)

The possibility of experimentally studying primary cosmic rays at the Moon's surface is considered. A mathematical simulations of showers initiated in the lunar regolith by high-energy particles of primary cosmic rays is performed. It is shown that such particles can in principle be recorded by simultaneously detecting three components of backscattered radiation (secondary neutrons, gamma rays, and radio emission).

Kalmykov, N. N.; Konstantinov, A. A.; Muhamedshin, R. A.; Podorozhniy, D. M.; Sveshnikova, L. G.; Turundaevskiy, A. N.; Tkachev, L. G.; Chubenko, A. P.; Vasilyev, O. A.

2013-01-01

87

Monopole annihilation and highest energy cosmic rays  

SciTech Connect

Cosmic rays with energies exceeding 10[sup 20] eV have been detected. The origin of these highest energy cosmic rays remains unknown. Established astrophysical acceleration mechanisms encounter severe difficulties in accelerating particles to these energies. Alternative scenarios where these particles are created by the decay of cosmic topological defects have been suggested in the literature. In this paper we study the possibility of producing the highest energy cosmic rays through a process that involves the formation of metastable magnetic monopole-antimonopole bound states and their subsequent collapse. The annihilation of the heavy monopole-antimonopole pairs constituting the monopolonia can produce energetic nucleons, [gamma] rays, and neutrinos whose expected flux we estimate and discuss in relation to experimental data so far available. The monopoles we consider are the ones that could be produced in the early Universe during a phase transition at the grand unification energy scale. We find that observable cosmic ray fluxes can be produced with monopole abundances compatible with present bounds.

Bhattacharjee, P. (Isaac Newton Institute, University of Cambridge, 20 Clarkson Road, Cambridge CB3 0EH (United Kingdom) Indian Institute of Astrophysics, Sarjapur Road, Koramangala, Bangalore 560 034 (India)); Sigl, G. (Department of Astronomy Astrophysics, Enrico Fermi Institute, The University of Chicago, Chicago, Illinois 60637-1433 (United States) NASA/Fermilab Astrophysics Center, Fermi National Accelerator Laboratory, Batavia, Illinois 60510-0500 (United States))

1995-04-15

88

Cosmic Ray physics with ARGO-YBJ  

NASA Astrophysics Data System (ADS)

The ARGO-YBJ experiment has been in stable data taking from November 2007 till February 2013 at the Yang-BaJing Cosmic Ray Laboratory (Tibet, P.R.China, 4300 m a.s.l.). It exploits the full coverage and the high altitude to detect air showers with an energy threshold as low as a few hundred GeV. The detector is made of a single layer of RPCs operated in streamer mode, fully instrumenting a central carpet of about 5800 m. A guard ring extends the partially instrumented area to about 11,000 m. The main results so far achieved on Cosmic Ray physics are reported.

Iacovacci, M.

2013-06-01

89

Catching Cosmic Rays with a DSLR  

ERIC Educational Resources Information Center

|Cosmic rays are high-energy particles from outer space that continually strike the Earth's atmosphere and produce cascades of secondary particles, which reach the surface of the Earth, mainly in the form of muons. These particles can be detected with scintillator detectors, Geiger counters, cloud chambers, and also can be recorded with commonly…

Sibbernsen, Kendra

2010-01-01

90

Cosmic Rays from Cygnus X-3  

Microsoft Academic Search

Today many investigators adhere to the idea that cosmic rays receive all their energy from discrete sources with interstellar space acting only as a diffusive medium. An object that accelerates particles to cosmic-ray velocities will almost inevitably produce gamma rays as well. Hence, gamma rays are therefore an effective probe of the source of cosmic radiation even though they account

P. Kevin MacKeown; Trevor C. Weekes

1985-01-01

91

Direct observations of galactic cosmic rays  

NASA Astrophysics Data System (ADS)

The mysterious " radiation ... entering our atmosphere from above" discovered by Hess in 1912 is now known to be dominated by relativistic charged particles, mostly with energies in the GeV-range, but extending to energies higher by many orders of magnitude. As none of these particles can penetrate the earth's atmosphere without interaction, detailed studies of their composition and energy spectra require observations with high-altitude balloons or spacecraft. This became possible only towards the middle of the 20th century. The direct measurements have now revealed much detail about the Galactic cosmic rays below 1015eV, but do not yet provide much overlap with the air-shower region of energies. A historic overview of the measurements is given, beginning with the realization that the majority of the cosmic rays are protons. The discovery and astrophysical significance of the heavier nuclei, and of the ultra-heavy nuclei beyond iron and up to the actinides, are then described, and measurements of the isotopic composition are discussed. Observations of the individual energy spectra are reviewed, and finally, the detection of electrons, positrons, and anti-protons in the cosmic rays, and the searches for exotic or unusual phenomena are summarized. Emphasis is given to the fact that all of these discoveries have become possible through the evolution of increasingly sophisticated detection techniques, a process that is continuing through the present time. The precise knowledge of the abundance distributions of the elements in the cosmic rays and of their isotopic composition permits a comparison with the "universal abundance scale" and provides strong constraints on the origin of the cosmic-ray material in the interstellar medium. "Clock-isotopes" reveal the time history of the particles. The shapes of the energy spectra of the individual cosmic-ray components are related to evolving ideas about particle acceleration and propagation in the Galaxy. In conclusion, prospects for future work are briefly discussed.

Müller, Dietrich

2012-08-01

92

The microphysics and macrophysics of cosmic rays  

NASA Astrophysics Data System (ADS)

This review paper commemorates a century of cosmic ray research, with emphasis on the plasma physics aspects. Cosmic rays comprise only ~10-9 of interstellar particles by number, but collectively their energy density is about equal to that of the thermal particles. They are confined by the Galactic magnetic field and well scattered by small scale magnetic fluctuations, which couple them to the local rest frame of the thermal fluid. Scattering isotropizes the cosmic rays and allows them to exchange momentum and energy with the background medium. I will review a theory for how the fluctuations which scatter the cosmic rays can be generated by the cosmic rays themselves through a microinstability excited by their streaming. A quasilinear treatment of the cosmic ray-wave interaction then leads to a fluid model of cosmic rays with both advection and diffusion by the background medium and momentum and energy deposition by the cosmic rays. This fluid model admits cosmic ray modified shocks, large scale cosmic ray driven instabilities, cosmic ray heating of the thermal gas, and cosmic ray driven galactic winds. If the fluctuations were extrinsic turbulence driven by some other mechanism, the cosmic ray background coupling would be entirely different. Which picture holds depends largely on the nature of turbulence in the background medium.

Zweibel, Ellen G.

2013-05-01

93

Cosmic Rays and Global Warming  

SciTech Connect

Some workers have claimed that the observed temporal correlations of (low level) terrestrial cloud cover with the cosmic ray intensity changes, due to solar modulation, 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 in some detail. So far, we have not found any evidence in support and so our conclusions are to doubt it. From the absence of corroborative evidence we estimate that less than 15% at the 95% confidence level, of the 11-year cycle warming variations are due to cosmic rays and less than 2% of the warming over the last 43 years is due to this cause. The origin of the correlation itself is probably the cycle of solar irradiance although there is, as yet, no certainty.

Sloan, T. [Physics Department, University of Lancaster, Lancaster, UK (United Kingdom); Wolfendale, A. W. [Physics Department, Durham University, Durham (United Kingdom)

2008-01-24

94

Cosmic Rays and Sunspot Numbers  

NSDL National Science Digital Library

In this activity students analyze and compare two or more graphs to determine if there is a correlation between sunspot number and the variation of cosmic ray flux. They discover that cosmic rays are very energetic particles, mostly protons and electrons, that enter the solar system from the depths of interstellar space and that although the Earth's magnetic field partially shields us from these particles, so too does the much more extended solar wind with its own magnetic field. This is a three-part lesson in which students will construct line graphs displaying the cosmic ray flux and sunspot numbers for a period of time, and then determine if there is a correlation. In order to compare these two sets of data, students will need to scale the data in order to visualize the results. Teacher and student notes for the graphing calculator are included.

Higley, Susan

95

Cosmic Ray Anisotropy with KASCADE  

NASA Astrophysics Data System (ADS)

The anisotropy of cosmic rays with energies in the region of the knee in the energy spectrum is investigated in three different persp ectives based on the arrival directions of about 150 Mio. extensive air showers measured by KASCADE. The different analyses are a harmonic analysis of the right ascension distribution and a point source search of showers above 0.5 PeV as well as an auto correlation analysis of showers above 100 PeV. All three analyses agree inside the statistical limits with an isotropic distribution of the arrival directions of cosmic rays.

Maier, G.; Antoni, T.; Apel, W. D.; Badea, F.; Bekk, K.; Bercuci, A.; Blümer, H.; Bozdog, H.; Brancus, I. M.; Büttner, C.; Chilingarian, A.; Daumiller, K.; Doll, P.; Engel, R.; Engler, J.; Feßler, F.; Gils, H. J.; Glasstetter, R.; Haungs, A.; Heck, D.; Hörandel, J. R.; Iwan, A.; Kampert, K. H.; Klages, H. O.; Mathes, H. J.; Mayer, H. J.; Milke, J.; Müller, M.; Obenland, R.; Oehlschläger, J.; Ostapchenko, S.; Petcu, M.; Rebel, H.; Risse, M.; Schatz, G.; Schieler, H.; Scholz, J.; Thouw, T.; Ulrich, H.; van Buren, J.; Vardanyan, A.; Weindl, A.; Wochele, J.; Zabierowski, J.

2003-07-01

96

People Interview: Cosmic rays uncover universe theories  

NASA Astrophysics Data System (ADS)

INTERVIEW Cosmic rays uncover universe theories David Smith talks to Paula Chadwick about why she is fascinated by cosmic and gamma rays, and how this is the year that their profile is going to be raised

2012-07-01

97

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

SciTech Connect

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

2012-12-15

98

Large-scale Distribution of Arrival Directions of Cosmic Rays Detected Above 1018 eV at the Pierre Auger Observatory  

NASA Astrophysics Data System (ADS)

A thorough search for large-scale anisotropies in the distribution of arrival directions of cosmic rays detected above 1018 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 1018 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 1018 eV from stationary Galactic sources densely distributed in the Galactic disk and predominantly emitting light particles in all directions.

Pierre Auger Collaboration; Abreu, P.; Aglietta, M.; Ahlers, M.; Ahn, E. J.; Albuquerque, I. F. M.; Allard, D.; Allekotte, I.; Allen, J.; Allison, P.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muñiz, J.; Alves Batista, R.; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; Andringa, S.; Anti?i'c, T.; Aramo, C.; Arganda, E.; Arqueros, F.; Asorey, H.; Assis, P.; Aublin, J.; Ave, M.; Avenier, M.; Avila, G.; Badescu, A. M.; Balzer, M.; Barber, K. B.; Barbosa, A. F.; Bardenet, R.; Barroso, S. L. C.; Baughman, B.; Bäuml, J.; Baus, C.; Beatty, J. J.; Becker, K. H.; Bellétoile, A.; Bellido, J. A.; BenZvi, S.; Berat, C.; Bertou, X.; Biermann, P. L.; Billoir, P.; Blanco, F.; Blanco, M.; Bleve, C.; Blümer, H.; Bohá?ová, M.; Boncioli, D.; Bonifazi, C.; Bonino, R.; Borodai, N.; Brack, J.; Brancus, I.; Brogueira, P.; Brown, W. C.; Bruijn, R.; Buchholz, P.; Bueno, A.; Buroker, L.; Burton, R. E.; Caballero-Mora, K. S.; Caccianiga, B.; Caramete, L.; Caruso, R.; Castellina, A.; Catalano, O.; Cataldi, G.; Cazon, L.; Cester, R.; Chauvin, J.; Cheng, S. H.; Chiavassa, A.; Chinellato, J. A.; Chirinos Diaz, J.; Chudoba, J.; Cilmo, M.; Clay, R. W.; Cocciolo, G.; Collica, L.; Coluccia, M. R.; Conceição, R.; Contreras, F.; Cook, H.; Cooper, M. J.; Coppens, J.; Cordier, A.; Coutu, S.; Covault, C. E.; Creusot, A.; Criss, A.; Cronin, J.; Curutiu, A.; Dagoret-Campagne, S.; Dallier, R.; Daniel, B.; Dasso, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; De Domenico, M.; De Donato, C.; de Jong, S. J.; De La Vega, G.; de Mello Junior, W. J. M.; de Mello Neto, J. R. T.; De Mitri, I.; de Souza, V.; de Vries, K. D.; del Peral, L.; del Río, M.; Deligny, O.; Dembinski, H.; Dhital, N.; Di Giulio, C.; Díaz Castro, M. L.; Diep, P. N.; Diogo, F.; Dobrigkeit, C.; Docters, W.; D'Olivo, J. C.; Dong, P. N.; Dorofeev, A.; dos Anjos, J. C.; Dova, M. T.; D'Urso, D.; Dutan, I.; Ebr, J.; Engel, R.; Erdmann, M.; Escobar, C. O.; Espadanal, J.; Etchegoyen, A.; Facal San Luis, P.; Falcke, H.; Fang, K.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Ferguson, A. P.; Fick, B.; Figueira, J. M.; Filevich, A.; Filip?i?, A.; Fliescher, S.; Fracchiolla, C. E.; Fraenkel, E. D.; Fratu, O.; Fröhlich, U.; Fuchs, B.; Gaior, R.; Gamarra, R. F.; Gambetta, S.; García, B.; Garcia Roca, S. T.; Garcia-Gamez, D.; Garcia-Pinto, D.; Garilli, G.; Gascon Bravo, A.; Gemmeke, H.; Ghia, P. L.; Giller, M.; Gitto, J.; Glass, H.; Gold, M. S.; Golup, G.; Gomez Albarracin, F.; Gómez Berisso, M.; Gómez Vitale, P. F.; Gonçalves, P.; Gonzalez, J. G.; Gookin, B.; Gorgi, A.; Gouffon, P.; Grashorn, E.; Grebe, S.; Griffith, N.; Grillo, A. F.; Guardincerri, Y.; Guarino, F.; Guedes, G. P.; Hansen, P.; Harari, D.; Harrison, T. A.; Harton, J. L.; Haungs, A.; Hebbeker, T.; Heck, D.; Herve, A. E.; Hill, G. C.; Hojvat, C.; Hollon, N.; Holmes, V. C.; Homola, P.; Hörandel, J. R.; Horvath, P.; Hrabovský, M.; Huber, D.; Huege, T.; Insolia, A.; Ionita, F.; Italiano, A.; Jansen, S.; Jarne, C.; Jiraskova, S.; Josebachuili, M.; Kadija, K.; Kampert, K. H.; Karhan, P.; Kasper, P.; Katkov, I.; Kégl, B.; Keilhauer, B.; Keivani, A.; Kelley, J. L.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Knapp, J.; Koang, D.-H.; Kotera, K.; Krohm, N.; Krömer, O.; Kruppke-Hansen, D.; Kuempel, D.; Kulbartz, J. K.; Kunka, N.; La Rosa, G.; Lachaud, C.; LaHurd, D.; Latronico, L.; Lauer, R.; Lautridou, P.; Le Coz, S.; Leão, M. S. A. B.; Lebrun, D.; Lebrun, P.; Leigui de Oliveira, M. A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; Link, K.; López, R.; Lopez Agüera, A.; Louedec, K.; Lozano Bahilo, J.; Lu, L.; Lucero, A.; Ludwig, M.; Lyberis, H.; Maccarone, M. C.; Macolino, C.; Maldera, S.; Maller, J.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Marin, J.; Marin, V.; Maris, I. C.; Marquez Falcon, H. R.; Marsella, G.; Martello, D.; Martin, L.; Martinez, H.; Martínez Bravo, O.; Martraire, D.; Masías Meza, J. J.; Mathes, H. J.; Matthews, J.; Matthews, J. A. J.; Matthiae, G.; Maurel, D.; Maurizio, D.; Mazur, P. O.; Medina-Tanco, G.; Melissas, M.; Melo, D.; Menichetti, E.; Menshikov, A.; Mertsch, P.; Messina, S.; Meurer, C.; Meyhandan, R.; Mi'canovi'c, S.; Micheletti, M. I.; Minaya, I. A.; Miramonti, L.; Molina-Bueno, L.; Mollerach, S.; Monasor, M.; Monnier Ragaigne, D.; Montanet, F.; Morales, B.; Morello, C.; Moreno, E.; Moreno, J. C.; Mostafá, M.; Moura, C. A.; Muller, M. A.; Müller, G.; Münchmeyer, M.; Mussa, R.; Navarra, G.; Navarro, J. L.; Navas, S.; Necesal, P.; Nellen, L.; Nelles, A.; Neuser, J.; Nhung, P. T.; Niechciol, M.; Niemietz, L.; Nierstenhoefer, N.; Nitz, D.; Nosek, D.; Nožka, L.; Oehlschläger, J.; Olinto, A.; Ortiz, M.; Pacheco, N.; Pakk Selmi-Dei, D.; Palatka, M.; Pallotta, J.; Palmieri, N.; Parente, G.; Parizot, E.; Parra, A.; Pastor, S.; Paul, T.

2012-12-01

99

Secular changes in the cosmic ray equator  

Microsoft Academic Search

Data of a number of latitude surveys of cosmic ray intensity with several crossings of the equator in the Atlantic Ocean, conducted during the 1954-1987 time period are analyzed to obtain the locations of the cosmic ray equator at different longitudes and epochs. These experimentally determined cosmic-ray-equator locations are compared with locations derived from simulated cosmic-ray intensities calculated as a

A. J. van der Walt; P. H. Stoker

1990-01-01

100

Search for Antimatter in Primary Cosmic Rays  

Microsoft Academic Search

COSMIC rays provide the only sample of the material outside the solar system which is available for examination and it even seems likely that some part of the cosmic ray flux originates outside our own galaxy. In the circumstances, it is understandable that there have been several searches for anti-nuclei in primary cosmic rays, partly so as to throw light

J. G. Greenhill; A. R. Clarke; H. Elliot

1971-01-01

101

Cosmic ray propagation in interstellar space  

Microsoft Academic Search

The astrophysics of cosmic rays is a very broad field of research, concerned with questions like where and how cosmic rays are accelerated, how they propagate and interact with the interstellar medium. In recent years a huge number of studies have been devoted to cosmic rays and to questions related to them as new and accurate observational data become available.

Ashraf Mohamed Samir Farahat

2005-01-01

102

Detectors for cosmic rays on ground and in Space  

NASA Astrophysics Data System (ADS)

The origin of cosmic rays has been a great mystery since they were discovered by Victor Hess in 1912. AGASA's observation of ultra-high-energy cosmic-rays (UHECR) possibly beyond the GZK (Greisen, Zatsepin and Kuzmin) cutoff stimulated the field in great deal. In addition, Kamiokande's detection of neutrinos from SN1987A and the detection of TeV gamma-rays from supernova remnants at H.E.S.S. have demonstrated the viability of neutrino and TeV gamma-ray astronomy for cosmic-ray research. A new generation of currently operating or soon-to-be-operating detectors for charged particles, gamma rays and neutrinos from cosmos will get us even closer to understanding the nature and origin of cosmic rays. Detectors for UHECRs, gamma rays and neutrinos are of particular importance in order to study the origins of cosmic rays since these particles are free from deflection due to magnetic fields. Detectors for antiparticles and gamma rays would be useful to detect cosmic rays originating from the decay of dark matter in the Universe. I will review these cosmic-ray detectors with particular emphasis on the differences of ground-based, balloon-borne and satellite-borne detectors.

Tajima, Hiroyasu

2007-10-01

103

Astroparticle Physics: Detectors for Cosmic Rays  

SciTech Connect

We describe the work that we have done over the last decade to design and construct instruments to measure properties of cosmic rays in Mexico. We describe the measurement of the muon lifetime and the ratio of positive to negative muons in the natural background of cosmic ray muons at 2000 m.a.s.l. Next we describe the detection of decaying and crossing muons in a water Cherenkov detector as well as a technique to separate isolated particles. We also describe the detection of isolated muons and electrons in a liquid scintillator detector and their separation. Next we describe the detection of extensive air showers (EAS) with a hybrid detector array consisting of water Cherenkov and liquid scintillator detectors, located at the campus of the University of Puebla. Finally we describe work in progress to detect EAS at 4600 m.a.s.l. with a water Cherenkov detector array and a fluorescence telescope at the Sierra Negra mountain.

Salazar, Humberto [Facultad de Ciencias Fisico-Matematicas, BUAP, Puebla Pue., 72570 (Mexico); Villasenor, Luis [Institute of Physics and Mathematics, Universidad Michoacana, Edificio C3, Ciudad Universitaria, Morelia, Mich., 58040 (Mexico)

2006-09-25

104

Cosmology, Relativity and Cosmic Rays  

NASA Astrophysics Data System (ADS)

This is a short review of the evolution of ideas and concepts about the Universe. It is based on the introductory talk given on the 25 of July 2008 within the Third School on Cosmic Rays and Astrophysics held in Arequipa, Peru.

López, Rebeca; Martínez, Humberto; Zepeda, Arnulfo

2009-04-01

105

Cosmic Ray Anisotropy with KASCADE  

Microsoft Academic Search

The anisotropy of cosmic rays with energies in the region of the knee in the energy spectrum is investigated in three different persp ectives based on the arrival directions of about 150 Mio. extensive air showers measured by KASCADE. The different analyses are a harmonic analysis of the right ascension distribution and a point source search of showers above 0.5

G. Maier; T. Antoni; W. D. Apel; F. Badea; K. Bekk; A. Bercuci; H. Blümer; H. Bozdog; I. M. Brancus; C. Büttner; A. Chilingarian; K. Daumiller; P. Doll; R. Engel; J. Engler; F. Feßler; H. J. Gils; R. Glasstetter; A. Haungs; D. Heck; J. R. Hörandel; A. Iwan; K. H. Kampert; H. O. Klages; H. J. Mathes; H. J. Mayer; J. Milke; M. Müller; R. Obenland; J. Oehlschläger; S. Ostapchenko; M. Petcu; H. Rebel; M. Risse; G. Schatz; H. Schieler; J. Scholz; T. Thouw; H. Ulrich; J. van Buren; A. Vardanyan; A. Weindl; J. Wochele; J. Zabierowski

2003-01-01

106

Cosmic Rays as Electrical Particles  

Microsoft Academic Search

Positive evidence that the primary cosmic rays consist of electrical particles is drawn from three types of experiments: 1. Latitude and directional asymmetry effects. Clay finds 83 percent as intense ionization at the equatorial minimum as in high latitudes. Of the remainder, Rossi's directional experiments show that about 12 percent at least is due to positively charged particles. Corresponding to

Arthur H. Compton

1936-01-01

107

Cosmic-ray sum rules  

SciTech Connect

We introduce new sum rules allowing to determine universal properties of the unknown component of the cosmic rays; we show how they can be used to predict the positron fraction at energies not yet explored by current experiments, and to constrain specific models.

Frandsen, Mads T. [Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP (United Kingdom); Masina, Isabella [Dip. di Fisica dell'Universita di Ferrara and INFN Sez. di Ferrara, Via Saragat 1, I-44100 Ferrara (Italy); CP3-Origins, University of Southern Denmark, Campusvej 55, DK-5230 Odense M (Denmark); Sannino, Francesco [CP3-Origins, University of Southern Denmark, Campusvej 55, DK-5230 Odense M (Denmark)

2011-06-15

108

Cosmic gamma-ray bursts  

Microsoft Academic Search

The results of the observation of cosmic gamma-ray bursts are discussed and available theoretical models are presented. Emphasis is placed on a cosmological model in which a gamma burst results from a powerful (? 1051–1053 erg) and very short ( ?10 –100 s) energy release which occurs in a compact ( ? 106–107 cm) region and gives rise to a

Konstantin A Postnov

1999-01-01

109

The Plasma Physics of Cosmic Rays  

NASA Astrophysics Data System (ADS)

Cosmic rays produce some of the most energetic emission in the Universe. They play a key role in the dynamics and energy balance of galactic gas, and allow us to probe galactic and intergalactic magnetic fields in the present epoch and over cosmic time. The acceleration and propagation of cosmic rays, and the mechanisms by which they interact collectively with their environments, are largely plasma physics problems. I will briefly review some salient aspects of cosmic ray astrophysics and describe recent progress toward understanding cosmic ray plasma physics.

Zweibel, Ellen

2012-03-01

110

The Plasma Physics of Cosmic Rays  

NASA Astrophysics Data System (ADS)

Cosmic rays are responsible for some of the most energetic emissions in the Universe, and new tools for studying them abound. Cosmic rays play a key role in galactic gas dynamics and energy balance, and allow us to probe galactic and intergalactic magnetic fields both in the present epoch and over cosmic time. The acceleration and propagation of high energy particles in astrophysical environments, and the mechanisms through which they interact collectively with the host medium, are largely plasma physics phenomena. I will briefly review some salient aspects of cosmic ray astrophysics, and describe recent progress in understanding cosmic ray plasma physics.

Gould Zweibel, Ellen

2012-05-01

111

Gamma ray bursts and cosmic ray origin  

Microsoft Academic Search

This paper presents the theoretical basis of the fireball\\/blast wave model, and some implications of recent results on GRB source models and cosmic-ray production from GRBs. BATSE observations of the prompt gamma-ray luminous phase, and Beppo-SAX and long wavelength afterglow observations of GRBs are briefly summarized. Derivation of spectral and temporal indices of an adiabatic blast wave decelerating in a

C. D. Dermer

2001-01-01

112

Gamma Ray Bursts and Cosmic Ray Origin  

Microsoft Academic Search

This paper presents the theoretical basis of the fireball\\/blast wave model, and some implications of recent results on GRB source models and cosmic-ray production from GRBs. BATSE observations of the prompt gamma-ray luminous phase, and Beppo-SAX and long wavelength afterglow observations of GRBs are briefly summarized. Derivation of spectral and temporal indices of an adiabatic blast wave decelerating in a

C. D. Dermer

2002-01-01

113

Gamma Ray Bursts and Cosmic Ray Origin  

Microsoft Academic Search

This paper presents the theoretical basis of the fireball\\/blast wave model,\\u000aand some implications of recent results on GRB source models and cosmic-ray\\u000aproduction from GRBs. BATSE observations of the prompt gamma-ray luminous\\u000aphase, and Beppo-SAX and long wavelength afterglow observations of GRBs are\\u000abriefly summarized. Derivation of spectral and temporal indices of an adiabatic\\u000ablast wave decelerating in a

C. D. Dermer

2002-01-01

114

Feasibility of Sea-level Cosmic-Ray Muon-Capture SNM Detection  

SciTech Connect

The first part of this report argues the average time between signal events for X-rays from negative muon capture on SNM is from a few to a few 10's of minutes, depending on how sophisticated one care's to make the detector. The second part of this report argues that the recoil proton background in the energy resolution window can be orders of magnitude larger than the expected signal. How could one evade this result? Firstly, one could conceive of a very highly segmented muon counter (or electromagnetic calorimeter) system to actually detect a stopping muon. This would be extraordinarily expensive for a large area and volume of a cargo container. There are also quite a few assumptions we applied to make the calculations tractable. For instance, we assumed the detector was fully efficient for a neutron recoil. probably something like 25% or 50% is more appropriate. However, probably the biggest uncertainty is the neutron energy spectrum. The Boehm et al. paper discusses the range of spectrum parameterizations, some of which are considerably softer and will lower the high-energy proton yield. This outcome is certainly possible. However, given the difference between signal and background rates, it would take a considerable change in detector parameters and particle yields to change the basic conclusion that this technique does not appear promising.

Rosenberg, L; Bernstein, A

2005-03-11

115

The discovery of cosmic rays  

NASA Astrophysics Data System (ADS)

The work leading to the discovery of cosmic rays by Victor Hess on August 7, 1912 is reviewed. In particular the almost forgotten work of the Italian Dominico Pacini in 1909-10 is described. Hess was awarded the Nobel Prize in Physics 1936, shared with Carl Anderson for the discovery of the positron. The reason for the long delay is discussed as well as the nominations and discussions put forward in the Nobel Committee's report to the Royal Swedish Academy of Sciences.

Carlson, Per; de Angelis, Alessandro

2011-04-01

116

Charged Cosmic Rays and Neutrinos  

NASA Astrophysics Data System (ADS)

High-energy neutrino astronomy has grown up, with IceCube as one of its main experiments having sufficient sensitivity to test "vanilla" models of astrophysical neutrinos. I review predictions of neutrino fluxes as well as the status of cosmic ray physics. I comment also briefly on an improvement of the Fermi-LAT limit for cosmogenic neutrinos and on the two neutrino events presented by IceCube first at "Neutrino 2012".

Kachelrieß, M.

2013-04-01

117

Cosmic rays in the classroom  

NASA Astrophysics Data System (ADS)

We use the context of astroparticle physics to introduce several fundamental concepts in physics and astrophysics. An activity has been developed using inexpensive materials that allows the reconstruction of the impact point and arrival direction of a cosmic ray particle measured by the Pierre Auger Observatory. The activity includes the discussion of fundamental concepts such as conservation of energy and momentum, centre of mass, trajectory, coordinate systems, speed, geo-orientation, time references and sky observation.

de Souza, Vitor; Alves Barros, Marcelo; César Marques Filho, Edson; Rodrigo Garbelotti, Cristiano; Alexandre João, Herbert

2013-03-01

118

Cosmic Connections: from Cosmic Rays to Gamma Rays, Cosmic Backgrounds and Magnetic Fields  

NASA Astrophysics Data System (ADS)

Combined data from gamma-ray telescopes and cosmic-ray detectors have produced some new surprising insights regarding intergalactic and galactic magnetic fields, as well as extragalactic background light. We review some recent advances, including a theory explaining the hard spectra of distant blazars and the measurements of intergalactic magnetic fields based on the spectra of distant sources. Furthermore, we discuss the possible contribution of transient galactic sources, such as past gamma-ray bursts and hypernova explosions in the Milky Way, to the observed flux of ultrahigh-energy cosmic-rays nuclei. The need for a holistic treatment of gamma rays, cosmic rays, and magnetic fields serves as a unifying theme for these seemingly unrelated phenomena.

Kusenko, Alexander

2013-01-01

119

Antennas for the detection of radio emission pulses from cosmic-ray induced air showers at the Pierre Auger Observatory  

NASA Astrophysics Data System (ADS)

The Pierre Auger Observatory is exploring the potential of the radio detection technique to study extensive air showers induced by ultra-high energy cosmic rays. The Auger Engineering Radio Array (AERA) addresses both technological and scientific aspects of the radio technique. A first phase of AERA has been operating since September 2010 with detector stations observing radio signals at frequencies between 30 and 80 MHz. In this paper we present comparative studies to identify and optimize the antenna design for the final configuration of AERA consisting of 160 individual radio detector stations. The transient nature of the air shower signal requires a detailed description of the antenna sensor. As the ultra-wideband reception of pulses is not widely discussed in antenna literature, we review the relevant antenna characteristics and enhance theoretical considerations towards the impulse response of antennas including polarization effects and multiple signal reflections. On the basis of the vector effective length we study the transient response characteristics of three candidate antennas in the time domain. Observing the variation of the continuous galactic background intensity we rank the antennas with respect to the noise level added to the galactic signal.

Abreu, P.; Aglietta, M.; Ahlers, M.; Ahn, E. J.; Albuquerque, I. F. M.; Allard, D.; Allekotte, I.; Allen, J.; Allison, P.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muñiz, J.; Alves Batista, R.; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; Andringa, S.; Anti?i?, T.; Aramo, C.; Arganda, E.; Arqueros, F.; Asorey, H.; Assis, P.; Aublin, J.; Ave, M.; Avenier, M.; Avila, G.; Badescu, A. M.; Balzer, M.; Barber, K. B.; Barbosa, A. F.; Bardenet, R.; Barroso, S. L. C.; Baughman, B.; Bäuml, J.; Baus, C.; Beatty, J. J.; Becker, K. H.; Bellétoile, A.; Bellido, J. A.; BenZvi, S.; Berat, C.; Bertou, X.; Biermann, P. L.; Billoir, P.; Blanco, F.; Blanco, M.; Bleve, C.; Blümer, H.; Bohá?ová, M.; Boncioli, D.; Bonifazi, C.; Bonino, R.; Borodai, N.; Brack, J.; Brancus, I.; Brogueira, P.; Brown, W. C.; Bruijn, R.; Buchholz, P.; Bueno, A.; Buroker, L.; Burton, R. E.; Caballero-Mora, K. S.; Caccianiga, B.; Caramete, L.; Caruso, R.; Castellina, A.; Catalano, O.; Cataldi, G.; Cazon, L.; Cester, R.; Chauvin, J.; Cheng, S. H.; Chiavassa, A.; Chinellato, J. A.; Chirinos Diaz, J.; Chudoba, J.; Cilmo, M.; Clay, R. W.; Cocciolo, G.; Collica, L.; Coluccia, M. R.; Conceição, R.; Contreras, F.; Cook, H.; Cooper, M. J.; Coppens, J.; Cordier, A.; Coutu, S.; Covault, C. E.; Creusot, A.; Criss, A.; Cronin, J.; Curutiu, A.; Dagoret-Campagne, S.; Dallier, R.; Daniel, B.; Dasso, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; De Domenico, M.; De Donato, C.; de Jong, S. J.; De La Vega, G.; de Mello Junior, W. J. M.; de Mello Neto, J. R. T.; De Mitri, I.; de Souza, V.; de Vries, K. D.; del Peral, L.; del Río, M.; Deligny, O.; Dembinski, H.; Dhital, N.; Di Giulio, C.; Díaz Castro, M. L.; Diep, P. N.; Diogo, F.; Dobrigkeit, C.; Docters, W.; D'Olivo, J. C.; Dong, P. N.; Dorofeev, A.; dos Anjos, J. C.; Dova, M. T.; D'Urso, D.; Dutan, I.; Ebr, J.; Engel, R.; Erdmann, M.; Escobar, C. O.; Espadanal, J.; Etchegoyen, A.; Facal San Luis, P.; Falcke, H.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Ferguson, A. P.; Fick, B.; Figueira, J. M.; Filevich, A.; Filip?i?, A.; Fliescher, S.; Fracchiolla, C. E.; Fraenkel, E. D.; Fratu, O.; Fröhlich, U.; Fuchs, B.; Gaior, R.; Gamarra, R. F.; Gambetta, S.; García, B.; Garcia Roca, S. T.; Garcia-Gamez, D.; Garcia-Pinto, D.; Gascon Bravo, A.; Gemmeke, H.; Ghia, P. L.; Giller, M.; Gitto, J.; Glass, H.; Gold, M. S.; Golup, G.; Gomez Albarracin, F.; Gómez Berisso, M.; Gómez Vitale, P. F.; Gonçalves, P.; Gonzalez, J. G.; Gookin, B.; Gorgi, A.; Gouffon, P.; Grashorn, E.; Grebe, S.; Griffith, N.; Grigat, M.; Grillo, A. F.; Guardincerri, Y.; Guarino, F.; Guedes, G. P.; Hansen, P.; Harari, D.; Harrison, T. A.; Harton, J. L.; Haungs, A.; Hebbeker, T.; Heck, D.; Herve, A. E.; Hojvat, C.; Hollon, N.; Holmes, V. C.; Homola, P.; Hörandel, J. R.; Horvath, P.; Hrabovský, M.; Huber, D.; Huege, T.; Insolia, A.; Ionita, F.; Italiano, A.; Jansen, S.; Jarne, C.; Jiraskova, S.; Josebachuili, M.; Kadija, K.; Kampert, K. H.; Karhan, P.; Kasper, P.; Katkov, I.; Kégl, B.; Keilhauer, B.; Keivani, A.; Kelley, J. L.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Knapp, J.; Koang, D.-H.; Kotera, K.; Krohm, N.; Krömer, O.; Kruppke-Hansen, D.; Kuempel, D.; Kulbartz, J. K.; Kunka, N.; La Rosa, G.; Lachaud, C.; LaHurd, D.; Latronico, L.; Lauer, R.; Lautridou, P.; Le Coz, S.; Leão, M. S. A. B.; Lebrun, D.; Lebrun, P.; Leigui de Oliveira, M. A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; Link, K.; López, R.; Lopez Agüera, A.; Louedec, K.; Lozano Bahilo, J.; Lu, L.; Lucero, A.; Ludwig, M.; Lyberis, H.; Maccarone, M. C.; Macolino, C.; Maldera, S.; Maller, J.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Marin, J.; Marin, V.; Maris, I. C.; Marquez Falcon, H. R.; Marsella, G.; Martello, D.; Martin, L.; Martinez, H.; Martínez Bravo, O.; Martraire, D.; Masías Meza, J. J.; Mathes, H. J.; Matthews, J.; Matthews, J. A. J.; Matthiae, G.; Maurel, D.; Maurizio, D.; Mazur, P. O.; Medina-Tanco, G.; Melissas, M.; Melo, D.; Menichetti, E.; Menshikov, A.; Mertsch, P.; Meurer, C.; Meyhandan, R.; Mi?anovi?, S.; Micheletti, M. I.; Minaya, I. A.; Miramonti, L.; Molina-Bueno, L.; Mollerach, S.; Monasor, M.; Monnier Ragaigne, D.; Montanet, F.; Morales, B.; Morello, C.; Moreno, E.; Moreno, J. C.; Mostafá, M.; Moura, C. A.; Muller, M. A.; Müller, G.; Münchmeyer, M.; Mussa, R.; Navarra, G.; Navarro, J. L.; Navas, S.; Necesal, P.; Nellen, L.; Nelles, A.; Neuser, J.; Nhung, P. T.; Niechciol, M.; Niemietz, L.; Nierstenhoefer, N.; Nitz, D.; Nosek, D.; Nožka, L.; Oehlschläger, J.; Olinto, A.; Ortiz, M.; Pacheco, N.; Pakk Selmi-Dei, D.; Palatka, M.; Pallotta, J.; Palmieri, N.; Parente, G.; Parizot, E.; Parra, A.; Pastor, S.; Paul, T.; Pech, M.; Pekala, J.; Pelayo, R.; Pepe, I. M.; Perrone, L.; Pesce, R.

2012-10-01

120

First results from the microwave air yield beam experiment (MAYBE): Measurement of GHz radiation for ultra-high energy cosmic ray detection  

NASA Astrophysics Data System (ADS)

We present measurements of microwave emission from an electron-beam induced air plasma performed at the 3 MeV electron Van de Graaff facility of the Argonne National Laboratory. Results include the emission spectrum between 1 and 15 GHz, the polarization of the microwave radiation and the scaling of the emitted power with respect to beam intensity. MAYBE measurements provide further insight on microwave emission from extensive air showers as a novel detection technique for Ultra-High Energy Cosmic Rays.

Williams, C.; Bohá?ová, M.; Bonifazi, C.; Cataldi, G.; Chemerisov, S.; de Mello Neto, J. R. T.; Facal San Luis, P.; Fox, B.; Gorham, P. W.; Hojvat, C.; Hollon, N.; Meyhandan, R.; Monasor, M.; Rouillé d'Orfeuil, B.; Santos, E. M.; Pochez, J.; Privitera, P.; Spinka, H.; Verzi, V.; Zhou, J.

2013-06-01

121

Cosmic-Ray Positive and Negative Electrons  

Microsoft Academic Search

A determination of the specific ionization of cosmic-ray particles, first, by a count of the number of drops per cm along cosmic-ray tracks on cloud-chamber photographs and, second, by measurements of the energy loss in lead has shown that the great bulk of the cosmic-ray particles of positive charge are positive electrons. The primary ionization was found to be about

Carl D. Anderson

1933-01-01

122

Cosmic ray Implications for Human Health  

NASA Astrophysics Data System (ADS)

There appears to be concern among some people about the possible effects of cosmic radiation on everyday life. The amount of cosmic radiation that reaches the Earth and its environment is a function of solar cycle, altitude and latitude. The possible effect of naturally occurring cosmic radiation on airplane crews and space flight personal is a subject of current study. This paper discusses the variables controlling the cosmic ray flux in the atmosphere and describes models and software that have been developed that provide quantitative information about the cosmic radiation exposure at flight altitudes. The discussion is extended to include the cosmic radiation exposure to manned spacecraft.

Shea, M. A.; Smart, D. F.

2000-07-01

123

Feasibility of Sea-Level Cosmic-Ray Muon-Capture SNM Detection.  

National Technical Information Service (NTIS)

The first part of this report argues the average time between signal events for X-rays from negative muon capture on SNM is from a few to a few 10's of minutes, depending on how sophisticated one care's to make the detector. The second part of this report...

L. Rosenberg A. Bernstein

2005-01-01

124

Feasibility of Sea-level Cosmic-Ray Muon-Capture SNM Detection  

Microsoft Academic Search

The first part of this report argues the average time between signal events for X-rays from negative muon capture on SNM is from a few to a few 10's of minutes, depending on how sophisticated one care's to make the detector. The second part of this report argues that the recoil proton background in the energy resolution window can be

L Rosenberg; A Bernstein

2005-01-01

125

Cosmic ray triggering using muon signal detected by the Hadronic Calorimeter of ATLAS  

Microsoft Academic Search

This paper presents the development of a matched filter syste m for muon detection using the muon output trigger signal, provided by the hadronic calorimeter of ATLAS detector, the Tile Calorimeter. A signal processing is done for this muon output to improve its signal-to-noise ratio and detection capability. The performance achieved for this system, using data from the testbeam period,

B. C. Ferreira; J. M. de Seixas; A. S. Cerqueira

126

High-energy cosmic ray interactions  

NASA Astrophysics Data System (ADS)

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; Orellana, Mariana; Reynoso, Matías M.; Vila, Gabriela S.

2009-04-01

127

High-energy cosmic ray interactions  

SciTech Connect

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)

2009-04-30

128

Cosmic Ray Acceleration in Supernova Remnants  

NASA Astrophysics Data System (ADS)

We review the main observational and theoretical facts about acceleration of Galactic cosmic rays in supernova remnants, discussing the arguments in favor and against a connection between cosmic rays and supernova remnants, the so-called supernova remnant paradigm for the origin of Galactic cosmic rays. Recent developments in the modeling of the mechanism of diffusive shock acceleration are discussed, with emphasis on the role of 1) magnetic field amplification, 2) acceleration of nuclei heavier than hydrogen, 3) presence of neutrals in the circumstellar environment. The status of the supernova-cosmic ray connection in the time of Fermi-LAT and Cherenkov telescopes is also discussed.

Blasi, P.

2011-06-01

129

Exploring the High-Energy Cosmic Ray Spectrum with a Toy Model of Cosmic Ray Diffusion  

Microsoft Academic Search

We introduce a static toy model of the cosmic ray (CR) universe in which cosmic ray propagation is taken to be diffusive and cosmic ray sources are distributed randomly with a density the same as that of local L* galaxies, $5 \\\\times 10^{-3}$ Mpc$^{-3}$. These sources \\

Roger Clay; Roland M. Crocker

2007-01-01

130

Cosmic ray modulation by interplanetary disturbances  

NASA Astrophysics Data System (ADS)

Interplanetary disturbances such as ICMEs (Interplanetary Coronal Mass Ejections) and CIRs (Corotating Interaction Regions), modulate high-energy cosmic rays reaching the Earth. Prior to the arrival of the disturbances at the Earth, ground based high-energy muon detectors can detect precursory effects in cosmic-ray anisotropy, such as precursory deficit and/or excess of intensity along the sunward IMF (Interplanetary Magnetic Field) direction. With suitable analyses, these precursors are found typically around 8 hours prior to the disturbance arrival at the Earth. The objective of this work is to analyze these precursors by using the Global Muon Detector Network (GMDN), an international network formed by four multidirectional muon detectors viewing a full range of the pitch angle measured from the sunward IMF direction. By analyzing the variation of the count rate global distribution of the observed intensity (instead of analyzing the count rate) precursory signatures can be enhanced when compared with analyses of count rates. For some events, it is possible to make almost a global distribution map of cosmic ray density using all the directional channels of the detectors. Precursory signature is generally accompanied by the interplanetary shock, but there are also some signatures not associated with the shock.

Braga, Carlos Roberto; Dal Lago, Alisson; Schuch, Nelson Jorge; da Silva, Marlos; Echer, Ezequiel; Demítrio Gonzalez Alarcon, Walter; Munakata, Kazuoki; Kuwabara, Takao; Kato, Chihiro; Bieber, John W.

131

Combined method for detecting hidden anomalies in galactic cosmic ray variations  

Microsoft Academic Search

A method has been proposed for detecting hidden periodicities in nonstationary finite time series with strong noise. The successive\\u000a application of the spectral singular expansion and wavelet transform makes it possible to calculate the energy of short signals\\u000a with an arbitrary form against a suppressing noise back-ground, the amplitude of which is several times as large as that of\\u000a a

V. V. Borog; A. V. Kryanev; D. K. Udumyan

2011-01-01

132

21st European Cosmic Ray Symposium  

NASA Astrophysics Data System (ADS)

European cosmic ray symposia (ECRS) are traditionally organised in years between those of international cosmic ray conferences (ICRC). The general topics are similar in both series, but European projects, and specifically the research preferences of the host country, are somewhat emphasised in European symposia. Precedence is also given to the discussion of effects that might be related to cosmic influences and are important for society, such as the global change of climate.

Király, P.; Kudela, K.; Stehlík, M.; Wolfendale, A. W.

2009-01-01

133

Development of cosmic x-ray polarimeter  

NASA Astrophysics Data System (ADS)

We present a performance study of a cosmic X-ray polarimeter which is based on the photoelectric effect in gas, and sensitive to a few to 30 keV range. In our polarimeter, the key device would be the 50 ?m pitch Gas Electron Multiplier (GEM). We have evaluated the modulation factor using highly polarized X-ray, provided by a synchrotron accelerator. In the analysis, we selected events by the eccentricity of the charge cloud of the photoelectron track. As a result, we obtained the relationship between the selection criteria for the eccentricity and the modulation factors; for example, when we selected the events which have their eccentricity of > 0.95, the polarimeter exhibited with the modulation factor of 0.32. In addition, we estimated the Minimum Detectable Polarization degree (MDP) of Crab Nebula with our polarimeter and found 10 ksec observation is enough to detect the polarization, if we adopt suitable X-ray mirrors.

Hayato, Asami; Tamagawa, Toru; Tsunoda, Naoko; Hashimoto, Shigehira; Miyamoto, Masao; Kohama, Mitsuhiro; Tokanai, Fuyuki; Hamagaki, Hideki; Inuzuka, Masahide; Miyasaka, Hiromasa; Sakurai, Ikuya; Makishima, Kazuo

2006-07-01

134

Solar Modulation of Cosmic Rays  

NASA Astrophysics Data System (ADS)

This is an overview of the solar modulation of cosmic rays in the heliosphere. It is a broad topic with numerous intriguing aspects so that a research framework has to be chosen to concentrate on. The review focuses on the basic paradigms and departure points without presenting advanced theoretical or observational details for which there exists a large number of comprehensive reviews. Instead, emphasis is placed on numerical modeling which has played an increasingly significant role as computational resources have become more abundant. A main theme is the progress that has been made over the years. The emphasis is on the global features of CR modulation and on the causes of the observed 11-year and 22-year cycles and charge-sign dependent modulation. Illustrative examples of some of the theoretical and observational milestones are presented, without attempting to review all details or every contribution made in this field of research. Controversial aspects are discussed where appropriate, with accompanying challenges and future prospects. The year 2012 was the centennial celebration of the discovery of cosmic rays so that several general reviews were dedicated to historical aspects so that such developments are briefly presented only in a few cases.

Potgieter, Marius

2013-06-01

135

Cygnus X-3 - Cosmic-ray powerhouse  

NASA Astrophysics Data System (ADS)

Cyg X-3, a high-energy X-ray binary located at the outskirts of the Galaxy which has been identified as the probable source of gamma rays of energies up to 10 PeV, is characterized in a survey of recent observational and theoretical investigations. The relationship between gamma rays and cosmic rays is reviewed; the observations establishing the 4.8-h periodicity of the gamma emissions are summarized; twin-jet/accretion-disk, pulsar, and dynamo models proposed to explain the Cyg X-3 emission are discussed; and the implications of very recent detections of secondary muons produced by neutrinos or some unknown primary particles (or by some unknown interaction of known particles) from Cyg X-3 are considered.

Smith, D. H.

1985-06-01

136

Cosmic rays and space weather  

NASA Astrophysics Data System (ADS)

It is well known that in periods of great FEP (Flare Energetic Particle), fluxes can be so big that memory of computers and other electronics in space may be destroyed, satellites and spacecrafts became dead (each year insurance companies paid more than 500,000,000 dollars for these failures). In these periods is necessary to switch off some part of electronics for short time to protect computer memories. These periods are also dangerous for astronauts on space-ships, and passengers and crew in commercial jets (especially during S5 radiation storms according to classification of NOAA). The problem is how to forecast exactly these dangerous phenomena. We show that exact forecast can be made by using high-energy particles (about 5-10 GeV/nucleon and higher) which transportation from the Sun is characterized by much bigger diffusion coefficient than for small and middle energy particles. Therefore high energy particles came from the Sun much more early (8-20 minutes after acceleration and escaping into solar wind) than main part of smaller energy particles caused dangerous situation for electronics and people health (about 30-60 minutes later). We describe here principles and experience of automatically working programs "FEP-Search-1 min", "FEP-Search-2 min","FEP-Search-5 min", developed and checked in the Emilio Segre' Observatory of Israel Cosmic Ray Center (2025 m above sea level, cut-off rigidity 10.8 GV). The second step is automatically determination of flare energetic particle spectrum, and then automatically determination of diffusion coefficient in the interplanetary space, time of ejection and energy spectrum of FEP in source; forecasting of expected FEP flux and radiation hazard for space-probes in space, satellites in the magnetosphere, jets and various objects in the atmosphere and on the ground. We will describe also the theory and experience of high energy cosmic ray using for forecasting of major geomagnetic storms accompanied by Forbush-effects (what influenced very much on communications, working of navigation systems, satellites and high-level technology systems in space and, the atmosphere, and on the ground). The review and original part will contain following parts: 1. Introduction (cosmic rays as object and instrument of space weather monitoring and forecasting). 2. On-line search of the start of great Flare Energetic Particle (FEP) events, automatically formation of Alerts, estimation of probability of false alerts and probability of missing alerts (realized in Israel Cosmic Ray Center and Emilio Segre’ Observatory). 3. On-line determination of flare energetic particle spectrum by the method of coupling functions. 4. Automatically determination of diffusion coefficient in the interplanetary space, time of ejection and energy spectrum of FEP in source; forecasting of expected FEP flux and radiation hazard for space-probes in space, satellites in the magnetosphere, jets and various objects in the atmosphere, and on the ground in dependence of cut-off rigidity. 5. Cosmic ray using for forecasting of major geomagnetic storms accompanied by Forbush-effects.

Dorman, L. I.

2003-04-01

137

A novel technique to detect special nuclear material using cosmic rays  

NASA Astrophysics Data System (ADS)

Resistive plate chambers (RPCs) are widely used in high energy physics for both tracking and triggering purposes, due to their excellent time resolution, rate capability, and good spatial resolution. RPCs can be produced cost-effectively on large scales, are of rugged build, and have excellent detection efficiency for charged particles. Our group has successfully built a muon scattering tomography (MST) prototype, using 12 RPCs to obtain tracking information of muons going through a target volume of ∼ 50 cm × 50 cm × 70 cm, reconstructing both the incoming and outgoing muon tracks. The required spatial granularity is achieved by using 330 readout strips per RPC with 1.5 mm pitch. The RPCs have shown an efficiency above 99% and an estimated intrinsic resolution below 1.1 mm. Due to these qualities, RPCs serve as excellent candidates for usage in volcano radiography.

Thomay, C.; Baesso, P.; Cussans, D.; Davies, J.; Glaysher, P.; Quillin, S.; Robertson, S.; Steer, C.; Vassallo, C.; Velthuis, J.

2012-12-01

138

Distinguishing spontaneous fission neutrons from cosmic-ray background  

Microsoft Academic Search

We have measured the neutron spectra of cosmic-rays and a spontaneous fission emitting source (Cf-252) using a neutron double scatter spectrometer. The energy range of measurements was 0.1-10 MeV where the spectrometer efficiency is determined to be up to 8.7%, depending on the separation between detection planes. Our cosmic-ray neutron spectrum measurement is in good agreement with the sea-level data

Leon Forman; Peter E. Vanier; Keith E. Welsh

2004-01-01

139

Cosmic Ray Diffusion Tensor Throughout the Heliosphere  

Microsoft Academic Search

We calculate the cosmic ray diffusion tensor based on a recently developed model of magnetohydrodynamic (MHD) turbulence in the expanding solar wind [Breech et al., 2008.]. Parameters of this MHD model are tuned by using published observations from Helios, Voyager 2, and Ulysses. We present solutions of two turbulence parameter sets and derive the characteristics of the cosmic ray diffusion

C. Pei; J. W. Bieber; B. Breech; R. A. Burger; J. Clem; W. H. Matthaeus

2008-01-01

140

Pulsars and possible local cosmic ray origin.  

National Technical Information Service (NTIS)

On the basis of the diffusion model of cosmic ray propagation in interstellar space the density of cosmic ray energy in the circumterrestrial space is calculated under assumption that the pulsars are indicators of place and time of supernovae explosions w...

H. M. Martirosyan

1987-01-01

141

Early cosmic ray research in France  

NASA Astrophysics Data System (ADS)

The French research on cosmic rays in the first half of the 20th century is summarized. The main experiments are described as the discovery of air cosmic ray showers by Pierre Auger. The results obtained at the French altitude laboratories like the ``Pic du Midi de Bigorre'' are also briefly presented.

Ravel, Olivier

2013-02-01

142

Early history of cosmic rays at Chicago  

NASA Astrophysics Data System (ADS)

Cosmic ray studies at the University of Chicago were started by Arthur Compton during the late 1920s. The high points of cosmic ray studies at Chicago under Compton and Marcel Schein are the focus of this report, which summarizes the research done at Chicago up to the end of World War II.

Yodh, Gaurang B.

2013-02-01

143

The Heliosphere and Galactic Cosmic Rays  

NASA Video Gallery

The heliosphere deflects galactic cosmic rays from entering the system. Galactic cosmic rays are a very high energy form of particle radiation that are extremely difficult to shield against and are harmful to astronauts. The boundaries surrounding our heliosphere deflect the majority of galactic radiation from the inner solar system.

Holly Zell

2010-09-28

144

The Highest-Energy Cosmic Rays  

Microsoft Academic Search

The search for the origin of cosmic rays with energies above 1018 eV has made considerable progress during the past few years. With new data from the High Resolution Fly's Eye experiment in Utah and the Pierre Auger Observatory in Argentina, a suppression of the cosmic ray flux above 5 × 1019 eV consistent with the predicted suppression arising from

James J. Beatty; Stefan Westerhoff

2009-01-01

145

Satellite Anomalies from Galactic Cosmic Rays  

Microsoft Academic Search

Anomalies in communication satellite operation have been caused by the unexpected triggering of digital circuits. Interactions with galactic cosmic rays were investigated as a mechanism for a number of these events. The mechanism assumed was the charging of the base-emitter capacitance of sensitive transistors to the turn-on voltage. The calculation of the cosmic ray event rate required the determination of

D. Binder; E. C. Smith; A. B. Holman

1975-01-01

146

The Corpuscular Explanation of Cosmic Rays  

Microsoft Academic Search

WITH reference to the attempts that are being made to determine whether the cosmic radiations are corpuscular or undulatory in character, such as those described by Bruno Rossi,1 there is one point which I have vainly tried to understand. Why is it assumed that such rays would or could have the high penetrating power of cosmic rays? As I tried

Frederick Soddy

1931-01-01

147

Feedback heating by cosmic rays in clusters of galaxies  

NASA Astrophysics Data System (ADS)

Recent observations show that the cooling flows in the central regions of galaxy clusters are highly suppressed. Observed active galactic nuclei (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 towards a significant non-thermal particle population. Previous studies have focused on the dynamical effects of cosmic ray pressure support, but none has 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 intra-cluster medium (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, Pc/Pg <~ 0.1 and ?Pc <~ 0.1?g, is well within observational bounds. Cosmic ray heating is a very attractive alternative to mechanical heating, and may become particularly compelling if Gamma-ray Large Array Space Telescope (GLAST) detects the ?-ray signature of cosmic rays in clusters.

Guo, Fulai; Oh, S. Peng

2008-02-01

148

The galactic origin of cosmic rays. II  

NASA Astrophysics Data System (ADS)

The cosmic ray pressure limit to cosmic ray acceleration in the interstellar medium (ISM) is considered. It is found that the beta equals 1 Alfven speed streaming limit imposes a new and strong constraint on supernova-ISM shock models of cosmic-ray acceleration. A more detailed analysis is, therefore, required. Ultra-high energy cosmic rays are also discussed, giving attention to sources of cosmic rays inside and outside the Galaxy. In connection with complexities and constraints, one source for all energies within all galaxies is finally considered, taking into account a flattening of the source in slope and the characteristics of spectrum and flux produced by the shock ejection of the envelope of a type I supernova.

Colgate, S. A.

149

Cosmic ray effects in microcalorimeter arrays  

Microsoft Academic Search

We have identified signals resulting from cosmic rays and environmental gamma rays depositing energy in the pixels and in the silicon frame of the Astro-E2\\/X-Ray Spectrometer microcalorimeter array. Coincidences between pixels and between the array and an anti-coincidence detector determined the nature of the events. Pulse shapes and amplitudes from the cosmic ray events helped refine the thermal model of

C. K. Stahle; K. R. Boyce; G. V. Brown; J. Cottam; E. Figueroa-Feliciano; M. Galeazzi; R. L. Kelley; D. McCammon; F. S. Porter; A. E. Szymkowiak; W. A. Tillotson

2004-01-01

150

Cosmic Rays: A Review for Astrobiologists  

NASA Astrophysics Data System (ADS)

Cosmic rays represent one of the most fascinating research themes in modern astronomy and physics. Significant progress is being made toward an understanding of the astrophysics of the sources of cosmic rays and the physics of interactions in the ultrahigh-energy range. This is possible because several new experiments in these areas have been initiated. Cosmic rays may hold answers to a great number of fundamental questions, but they also shape our natural habitat and influence the radiation environment of our planet Earth. The importance of the study of cosmic rays has been acknowledged in many fields, including space weather science and astrobiology. Here, we concentrate on the astrobiological aspects of cosmic rays with regard to the enormous amount of new data available, some of which may, in fact, improve our knowledge about the radiation of cosmic origin on Earth. We focus on fluxes arriving at Earth and doses received, and will guide the reader through the wealth of scientific literature on cosmic rays. We have prepared a concise and self-contained source of data and recipes useful for performing interdisciplinary research in cosmic rays and their effects on life on Earth.

Ferrari, Franco; Szuszkiewicz, Ewa

2009-05-01

151

Cosmic multi-muon bundles detected by DELPHI  

Microsoft Academic Search

The DELPHI detector at LEP, located 100 m underground, has been used to detect multi-muon bundles originated from cosmic ray interactions in the atmosphere. The cosmic events registered during the years 1999 and 2000 correspond roughly to 1.6 106 s of effective run time. The muon multiplicity distribution has been measured over a wide range of multiplicities. This paper provides

J. Ridky; P. Travnicek

2003-01-01

152

Gamma-ray Constraints on Cosmic Rays in Galactic Winds  

NASA Astrophysics Data System (ADS)

Our group is constructing a hybrid thermal gas and cosmic-ray pressure driven wind model. This model is built on past work by Breitschwerdt et al. (1991) and Zirakashvili et al. (1996), and was motivated by unexplained high latitude Galactic X-ray emission observed by ROSAT, and further tested with radio synchrotron observations. In this poster, the role of cosmic-ray protons in generating gamma-ray emission in a Galactic wind is explored. In interacting with the wind plasma, cosmic-ray protons have three mechanisms to generate gamma-rays (pion production, Bremsstrahlung, and inverse Compton scattering), which can be detected by the Fermi Gamma-ray Space Telescope. To test the model, we have calculated the gamma-ray intensity from the wind model of Everett et al (2010), and we compare these predictions to the observed emission in the central Milky Way. Also, we have recently developed a new wind model which includes an azimuthal magnetic field and galactic rotation; we compare the driving in this improved model to the previous one, and report on the gamma-ray emissivity of this model as well. In the future we will apply this model to other galaxies which are observed to have a large scale wind, such as M82 and NGC 253. Understanding the high latitude gamma-ray emission from relativistic particles in galactic winds may help to constrain dark-matter models as well. This work has been supported by NASA through grant NNX10AO50G, and by the NSF through grants NSF AST-0907837 and NSF PHY-0821899 (to the Center for Magnetic Self-Organization in Laboratory and Astrophysical Plasmas).

Hu, Kaiqi; Everett, J. E.; Zweibel, E. G.

2011-01-01

153

Origin of Galactic Cosmic Rays  

NASA Astrophysics Data System (ADS)

The origin of the bulk of cosmic rays (CRs) observed at Earth is the topic of a century long investigation, paved with successes and failures. From the energetic point of view, supernova remnants (SNRs) remain the most plausible sources of CRs up to rigidity ˜106-107GV. This confidence somehow resulted in the construction of a paradigm, the so-called SNR paradigm: CRs are accelerated through diffusive shock acceleration in SNRs and propagate diffusively in the Galaxy in an energy dependent way. Qualitative confirmation of the SNR acceleration scenario has recently been provided by gamma ray and X-ray observations. Diffusive propagation in the Galaxy is probed observationally through measurement of the secondary to primary nuclei flux ratios (such as B/C). There are however some weak points in the paradigm, which suggest that we are probably missing some physical ingredients in our models. The theory of diffusive shock acceleration at SNR shocks predicts spectra of accelerated particles which are systematically too hard compared with the ones inferred from gamma ray observations. Moreover, hard injection spectra indirectly imply a steep energy dependence of the diffusion coefficient in the Galaxy, which in turn leads to anisotropy larger than the observed one. Moreover recent measurements of the flux of nuclei suggest that the spectra have a break at rigidity ˜200GV, which does not sit well with the common wisdom in acceleration and propagation. In this paper I will review these new developments and suggest some possible implications.

Blasi, Pasquale

2013-06-01

154

Cosmic-Ray Modulation Equations  

NASA Astrophysics Data System (ADS)

The temporal variation of the cosmic-ray intensity in the heliosphere is called cosmic-ray modulation. The main periodicity is the response to the 11-year solar activity cycle. Other variations include a 27-day solar rotation variation, a diurnal variation, and irregular variations such as Forbush decreases. General awareness of the importance of this cosmic-ray modulation has greatly increased in the last two decades, mainly in communities studying cosmogenic nuclides, upper atmospheric physics and climate, helio-climatology, and space weather, where corrections need to be made for these modulation effects. Parameterized descriptions of the modulation are even used in archeology and in planning the flight paths of commercial passenger jets. The qualitative, physical part of the modulation is generally well-understood in these communities. The mathematical formalism that is most often used to quantify it is the so-called Force-Field approach, but the origins of this approach are somewhat obscure and it is not always used correct. This is mainly because the theory was developed over more than 40 years, and all its aspects are not collated in a single document. This paper contains a formal mathematical description intended for these wider communities. It consists of four parts: (1) a description of the relations between four indicators of "energy", namely energy, speed, momentum and rigidity, (2) the various ways of how to count particles, (3) the description of particle motion with transport equations, and (4) the solution of such equations, and what these solutions mean. Part (4) was previously described in Caballero-Lopez and Moraal (J. Geophys. Res, 109: A05105, doi: 10.1029/2003JA010358, 2004). Therefore, the details are not all repeated here. The style of this paper is not to be rigorous. It rather tries to capture the relevant tools to do modulation studies, to show how seemingly unrelated results are, in fact, related to one another, and to point out the historical context of some of the results. The paper adds no new knowledge. The summary contains advice on how to use the theory most effectively.

Moraal, H.

2013-06-01

155

Supersymmetry and ultrahigh-energy cosmic rays  

SciTech Connect

The production of supersymmetric particles in ultrahigh-energy cosmic-ray interactions in the atmosphere is investigated. We find that the pair production and subsequent decay of a light (approx.3--5 GeV) gluino can lead to fluxes of neutral, weakly interacting superparticles which can be comparable to neutrino fluxes. Relevant processes for detecting photinos or scalar neutrinos in large neutrino detectors are discussed and several reactions with cross sections as large as those of ordinary ..nu.. interactions are examined.

Robinett, R.W.

1985-07-29

156

SLAC Cosmic Ray Telescope Facility  

SciTech Connect

SLAC does not have a test beam for the HEP detector development at present. We have therefore created a cosmic ray telescope (CRT) facility, which is presently being used to test the FDIRC prototype. We have used it in the past to debug this prototype with the original SLAC electronics before going to the ESA test beam. Presently, it is used to test a new waveform digitizing electronics developed by the University of Hawaii, and we are also planning to incorporate the new Orsay TDC/ADC electronics. As a next step, we plan to put in a full size DIRC bar box with a new focusing optics, and test it together with a final SuberB electronics. The CRT is located in building 121 at SLAC. We anticipate more users to join in the future. This purpose of this note is to provide an introductory manual for newcomers.

Va'vra, J.

2010-02-15

157

Sulphur mountain: Cosmic ray intensity records  

SciTech Connect

This book deals with the comic ray intensity registrations at the Sulphur Mountain Cosmic Ray Laboratory. The time series of intensity form a valuable data-set, for studying cosmic ray intensity variations and their dependence on solar activity. The IGY neutron monitor started operating from July 1, 1957 and continued through 1963. Daily mean values are tabulated for the period and these are also represented in plots. This monitor was set up by the National Research Council of Canada.

Venkatesan, D.; Mathews, T.

1985-01-01

158

Cosmic Rays Variations and Human Physiological State  

NASA Astrophysics Data System (ADS)

It was obtained in our previous investigations that geomagnetic activity as an indirect indicator of solar activity correlates with some human physiological and psycho-physiological parameters. A lot of studies indicate that other parameters of space weather like cosmic rays Forbush decreases affect myocardial infarction, brain stroke, car accidents, etc. The purpose of that work was to study the effect of cosmic rays variations on human physiological status. It was established that the decrease in cosmic rays intensity was related to an increase in systolic and diastolic blood pressure and reported subjective psycho-physiological complaints in healthy volunteers.

Dimitrova, S.

2009-12-01

159

Cosmic-Ray Spectra in Interstellar Space  

SciTech Connect

At energies below {approx}300 MeV/nuc our knowledge of cosmic-ray spectra outside the heliosphere is obscured by the energy loss that cosmic rays experience during transport through the heliosphere into the inner solar system. This paper compares measurements of secondary electron-capture isotope abundances and cosmic-ray spectra from ACE with a simple model of interstellar propagation and solar modulation in order to place limits on the range of interstellar spectra that are compatible with both sets of data.

Mewaldt, R.A.; Cummings, A.C.; Davis, A.J.; Leske, R.A.; Stone, E.C. [California Institute of Technology, Pasadena, CA 91126 (United States); Wiedenbeck, M.E. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena CA 91190 (United States); Scott, L.M.; Binns, W.R.; Israel, M.H. [Department of Physics, Washington University, St. Louis MO. 63105 (United States); Rosenvinge, T.T. von [NASA/Goddard Space Flight Center, Greenbelt MD 20771 (United States)

2004-09-15

160

Cosmic ray propagation in the local superbubble  

NASA Astrophysics Data System (ADS)

It is suggested that a ring of HI gas lying in the galactic plane is part of a supershell which formed some 3 x to the 7th power years ago. The consequences of a closed magnetic supershell for cosmic ray propagation are examined and it is concluded that there is no evidence which precludes the production and trapping of cosmic rays in such a region. A consequence of superbubble confinement is that the mean age of cosmic rays would be independent of energy. This can be tested by high energy observations of the isotopic composition of Be.

Steitmatter, R. E.; Balasubrahmanyan, V. K.; Protheroe, R. J.; Ormes, J. F.

1984-09-01

161

Cosmic ray propagation in the local superbubble  

NASA Astrophysics Data System (ADS)

It is suggested that a ring of HI gas lying in the galactic plane is part of a supershell which formed some 3 x 10 to the 7th power years ago. The consequences of a closed magnetic supershell for cosmic ray propagation are examined and it is concluded that there is no evidence which precludes the production and trapping of cosmic rays in such a region. A consequence of superbubble confinement is that the mean age of cosmic rays would be independent of energy. This can be tested by high energy observations of the isotopic composition of Be.

Streitmatter, R. E.; Balasubrahmanyan, V. K.; Ormes, J. F.; Protheroe, R. J.

1985-02-01

162

Cosmic ray ionization of lower Venus atmosphere  

NASA Astrophysics Data System (ADS)

The high energy solar and galactic cosmic rays are known to ionize Earth's atmosphere. The cosmic ray degradation and production of electron-ion pairs in Venus ionosphere are computed. At lower altitudes, the Venus atmosphere is dense and cosmic ray particles are known to decay and give rise to various charged and neutral particles. The flux and degradation of dominant cascade particles, namely neutrinos and pions, are computed and ionization contributions at lower altitudes are estimated. Using the height profile of pion flux, the muon ray flux is computed and used to estimate ionization at lower altitudes. It is shown that cosmic-ray produced ionization descends to much lower altitudes intercepting the thickness of the Venus cloud deck. The dynamical features of the Venus cloud deck are used to show the likely charging and charge separation processes resulting in cloud-to-cloud lightning discharges.

Upadhyay, H. O.; Singh, R. N.

1995-04-01

163

A theory of cosmic rays  

NASA Astrophysics Data System (ADS)

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 the 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.

Dar, Arnon; de Rújula, A.

2008-09-01

164

A Simplified Model for the Acceleration of Cosmic Ray Particles  

ERIC Educational Resources Information Center

|Two important questions concerning cosmic rays are: Why are electrons in the cosmic rays less efficiently accelerated than nuclei? How are particles accelerated to great energies in ultra-high energy cosmic rays? In order to answer these questions we construct a simple model of the acceleration of a charged particle in the cosmic ray. It is not…

Gron, Oyvind

2010-01-01

165

Cosmic-ray positrons: are there primary sources?  

Microsoft Academic Search

Galactic cosmic rays consist of primary and secondary particles. Primary cosmic rays are thought to be energized by first order Fermi acceleration processes at supernova shock fronts within our Galaxy. The cosmic rays that eventually reach the Earth from this source are mainly protons and atomic nuclei, but also include electrons. Secondary cosmic rays are created in collisions of primary

Stéphane Coutu; Steven W. Barwick; James J. Beatty; Amit Bhattacharyya; Chuck R. Bower; Christopher J. Chaput; Georgia A. de Nolfo; Michael A. DuVernois; Allan Labrador; Shawn P. McKee; Dietrich Müller; James A. Musser; Scott L. Nutter; Eric Schneider; Simon P. Swordy; Gregory Tarlé; Andrew D. Tomasch; Eric Torbet

1999-01-01

166

DISTINGUISHING SPONTANEOUS FISSION NEUTRONS FROM COSMIC-RAY BACKGROUND.  

SciTech Connect

We have measured the neutron spectra of cosmic-rays and a spontaneous fission emitting source (Cf-252) using a neutron double scatter spectrometer. The energy range of measurements was 0.1-10 MeV where the spectrometer efficiency is determined to be up to 8.7% depending on the separation between detection planes. Our cosmic-ray neutron spectrum measurement is in good agreement with the sea-level data reported by Goldhagen and his co-workers. In the energy range 0.1-1.0 MeV, the cosmic-ray and Cf-252 spectra are different and separable. This difference is expected from the applicable models that describe the phenomena, ''equilibrium slowing down'' (cosmic-rays) and ''Maxwellian kinetic temperature'' emission (spontaneous fission). We show that >80% of Cf-252 neutrons and <25% of cosmic-ray related neutrons are emitted in this energy range of measurement, and conclude that neutron spectroscopy provides effective ways to distinguish a fission source from the cosmic-ray background.

FORMAN,L.

2004-08-02

167

Distinguishing spontaneous fission neutrons from cosmic-ray background  

NASA Astrophysics Data System (ADS)

We have measured the neutron spectra of cosmic-rays and a spontaneous fission emitting source (Cf-252) using a neutron double scatter spectrometer. The energy range of measurements was 0.1-10 MeV where the spectrometer efficiency is determined to be up to 8.7%, depending on the separation between detection planes. Our cosmic-ray neutron spectrum measurement is in good agreement with the sea-level data reported by Goldhagen and his co-workers. In the energy range 0.1-1.0 MeV, the cosmic-ray and Cf-252 spectra are different and separable. This difference is expected from the applicable models that describe the phenomena, 'equilibrium slowing down' (cosmic-rays) and 'Maxwellian kinetic temperature' emission (spontaneous fission). We show that >80% of Cf-252 neutrons and <25% of cosmic-ray related neutrons are emitted in this energy range of measurement, and conclude that neutron spectroscopy provides effective ways to distinguish a fission source from the cosmic-ray background.

Forman, Leon; Vanier, Peter E.; Welsh, Keith E.

2004-10-01

168

The anisotropy of multi-TeV cosmic rays  

NASA Astrophysics Data System (ADS)

The arrival directions of cosmic rays will be isotropized by the deflection of these charged particles in the Galactic magnetic fields. For example, a 10 TeV proton in a typical Galactic field of 2 micro Gauss has a gyroradius of only 0.005 parsec (=1000 AU) which is much smaller than the distance to any postulated sources. However, observations of TeV cosmic rays by Milagro, Tibet III, ARGO, and IceCube, show anisotropies on both large and small angular scales. These observations require the detection of large numbers of cosmic rays because the anisotropies are less than a few parts in 1000. The large angular scale anisotropies, such as a dipole, could point to diffusion from a nearby source, but the smaller scale anisotropies of extent ~10 degrees are much more difficult to explain. Possibilities that have been explored in the literature include magnetic funneling of cosmic rays from nearby sources and acceleration by magnetic reconnection in the heliosphere's magnetotail. No matter what the mechanism, these observations provide new information about cosmic ray production, nearby magnetic fields, and how the cosmic rays observed at Earth are affected by their propagation.

Dingus, Brenda

2013-02-01

169

Ground level radiation from cosmic ray shower secondaries  

NASA Astrophysics Data System (ADS)

Most cosmic ray secondaries never reach ground level, however high energy cosmic rays produce muons and neutrons which do. These particles are known to cause increased radiation and cancer rates under current day cosmic ray flux. Episodic increases in the high energy cosmic ray flux increase this radiation, and thus the risk to biological life. Our work models the flux of neutrons and muons produced by high energy cosmic rays, exploring the possibility of biological impact due to extended periods of increase high energy cosmic ray muon flux. Our results find secondary muon radiation to be significant in cosmic ray flux increasing events.

Overholt, Andrew

2013-04-01

170

Cosmic Rays in the Earth'S Magnetic Field.  

National Technical Information Service (NTIS)

Studies are presented of the behavior of cosmic rays in the earth's magnetic field. It discusses the theory of motion of charged particles in an idealized field model and presents results of trajectory calculations of asymptotic directions and cutoff rigi...

L. I. Dorman V. S. Smirnov M. I. Tyasto

1973-01-01

171

Cosmic rays from pulsars and magnetars  

NASA Astrophysics Data System (ADS)

We compare the expected abundance of cosmic ray electrons and positrons from pulsars and magnetars. We assume that the distribution of infant pulsars and magnetars follows that of high-mass stars in the Milky Way and that the production rate of cosmic rays is proportional to the spin-down and magnetic-decay power of pulsars and magnetars, respectively. In combination with primary and secondary cosmic ray leptons from other sources (especially supernova remnants), we find that both magnetars and pulsars can easily account for the observed cosmic ray spectrum, in particular the dip seen by HESS (High-Energy Stereoscopic System) at several TeV and the increase in positron fraction found by PAMELA (Payload for Antimatter Exploration and Light Nuclei Astrophysics).

Heyl, Jeremy S.; Gill, Ramandeep; Hernquist, Lars

2010-07-01

172

Cosmic ray gradients in the outer heliosphere.  

NASA Astrophysics Data System (ADS)

Pioneer 10 and 11 spacecraft are now probing the outer heliosphere. The authors have used the UCSD instruments on board to study the gradient, and to look at the time and spatial variations of the cosmic ray intensities.

Fillius, W.; Wake, B.; Ip, W.-H.; Axford, I.

1983-08-01

173

Cosmic ray test of INO RPC stack  

NASA Astrophysics Data System (ADS)

The India-based Neutrino Observatory (INO) collaboration is planning to build a 50 kt magnetised iron calorimeter (ICAL) detector using glass Resistive Plate Chambers (RPCs) as active detector elements. A stack of 12 such glass RPCs of 1 m ×1 m in area is tracking cosmic ray muons for over three years. In this paper, we will review the constructional aspects of the stack and discuss the performance of the RPCs using this cosmic ray data.

Bhuyan, M.; Datar, V. M.; Kalmani, S. D.; Lahamge, S. M.; Mondal, N. K.; Nagaraj, P.; Pal, S.; Reddy, L. V.; Redij, A.; Samuel, D.; Saraf, M. N.; Satyanarayana, B.; Shinde, R. R.; Verma, P.

2012-01-01

174

Galactic Cosmic Rays and the Environment  

Microsoft Academic Search

SH.3.6.14 Galactic Cosmic Rays and the Environment G. Cini Castagnoli, G. Bonino, P. Della Monica, C. Taricco Istituto di Cosmogeofisica, CNR, Corso Fiume 4, 10133 Torino, Italy and Dipartimento di Fisica Generale, Università di Torino, Via P. Giuria 1, 10125 Torino Recently Svensmark and Friis-Christensen (1997) reported an indication that the Galactic Cosmic Rays (GCR) modulated by the solar wind

G. Cini Castagnoli

1999-01-01

175

Chaotic Properties of High Energy Cosmic Rays  

Microsoft Academic Search

Using the dimension of correlation analysis, we study the time series intervals of the high-energy cosmic ray data, obtained in the mount of Chacaltaya, in the experiment S.Y.S. Some of the analyzed groups present a fractal dimension close to 3. This fractal dimension seems to show that the transport system of cosmic ray would be chaotic under some circumstances. Results

A. Ticona; R. Ticona; N. Martinic; I. Poma; R. Gutierrez; R. Calle; E. Rodriguez

2006-01-01

176

EDITORIAL: Focus on High Energy Cosmic Rays FOCUS ON HIGH ENERGY COSMIC RAYS  

NASA Astrophysics Data System (ADS)

The topic of high-energy cosmic rays has recently attracted significant attention. While the AGASA and HiRes Observatories have closed after many years of successful operation, the Pierre Auger Observatory began taking data in January 2004 and the first results have been reported. Plans for the next generation of instruments are in hand: funding is now being sought for the northern phase of the Auger Observatory and plans for a space detector, JEM-EUSO, to be launched in 2013-14 are well advanced with the long-term target of a dedicated satellite for the 2020s. It therefore seemed an appropriate time to make a collection of outstanding and original research articles from the leading experimental groups and from some of the theorists who seek to interpret the hard-won data and to speculate on the origin of the highest energy cosmic rays. This focus issue in New Journal of Physics on the topic of high energy cosmic rays, contains a comprehensive account of the work of the Yakutsk group (A A Ivanov, S P Knurenko and I Ye Sleptsov) who have used Cerenkov radiation produced by shower particles in the air to provide the basis for energy calibration. This technique contrasts with that of detecting fluorescence radiation from space that is proposed for the JEM-EUSO instrument to be placed on the International Space Station in 2013, described by Y Takahashi. Supplementing this is an article by A Santangelo and A Petrolini describing the scientific goals, requirements and main instrument features of the Super Extreme Universe Space Observatory mission (S-EUSO). The use of fluorescence light to measure energies was the key component of the HiRes instrument and is also used extensively by the Pierre Auger Collaboration so an article, by F Arqueros, F Blanco and J Rosado, summarizing the properties of fluorescence emission, still not fully understood, is timely. M Nagano, one of the architects of the AGASA Observatory, has provided an overview of the experimental situation with regard to the energy spectrum of the highest energy cosmic rays. The remaining contributions are of a more theoretical nature and discuss propagation (T Stanev), the time structure of multi-messenger signals (G H W Sigl), ultra-high energy cosmic ray production near black holes (A Yu Neronov, D V Semikoz and I I Tkachev), production in jets associated with black holes (C D Dermer, S Razzaque, J Finke and A Atoyan) and emission from a specific object, Cen A (M Kachelriess, S S Ostapchenko and R Tomas). Additionally the potential of high energy cosmic rays to give information about features of hadronic interactions, specifically the cross-section for p-air collisions, is discussed in the paper by R Ulrich et al. We thank all our authors most sincerely for their efforts and Tim Smith and his editorial team for their hard work. We believe that this collection of articles will be of great value to workers in the field: further contributions to this focus issue will be published during the course of 2009. Focus on High Energy Cosmic Rays Contents The cosmic ray energy spectrum as measured using the Pierre Auger Observatory Giorgio Matthiae The northern site of the Pierre Auger Observatory Johannes Blümer and the Pierre Auger Collaboration Searching for new physics with ultrahigh energy cosmic rays Floyd W Stecker and Sean T Scully On the measurement of the proton-air cross section using air shower data R Ulrich, J Blümer, R Engel, F Schüssler and M Unger High energy radiation from Centaurus A M Kachelrieß, S Ostapchenko and R Tomàs Ultra-high-energy cosmic rays from black hole jets of radio galaxies C D Dermer, S Razzaque, J D Finke and A Atoyan Ultra-high energy cosmic ray production in the polar cap regions of black hole magnetospheres A Yu Neronov, D V Semikoz and I I Tkachev Time structure and multi-messenger signatures of ultra-high energy cosmic ray sources Günter Sigl Propagation of ultrahigh-energy cosmic rays Todor Stanev Search for the end of the energy spectrum of primary cosmic rays M Nagano Analysis of the fluorescence emission from atmospheric ni

Teshima, Masahiro; Watson, Alan A.

2009-06-01

177

Cosmic ray acceleration in young supernova remnants  

NASA Astrophysics Data System (ADS)

We investigate the appearance of magnetic field amplification resulting from a cosmic ray escape current in the context of supernova remnant shock waves. The current is inversely proportional to the maximum energy of cosmic rays, and is a strong function of the shock velocity. Depending on the evolution of the shock wave, which is drastically different for different circumstellar environments, the maximum energy of cosmic rays as required to generate enough current to trigger the non-resonant hybrid instability that confines the cosmic rays follows a different evolution and reaches different values. We find that the best candidates to accelerate cosmic rays to ˜ few PeV energies are young remnants in a dense environment, such as a red supergiant wind, as may be applicable to Cassiopeia A. We also find that for a typical background magnetic field strength of 5 ?G the instability is quenched in about 1000 years, making SN1006 just at the border of candidates for cosmic ray acceleration to high energies.

Schure, K. M.; Bell, A. R.

2013-10-01

178

Multi-spectra Cosmic Ray Flux Measurement  

NASA Astrophysics Data System (ADS)

The Earth's upper atmosphere is constantly bombarded by rain of charged particles known as primary cosmic rays. These primary cosmic rays will collide with the atmospheric molecules and create extensive secondary particles which shower downward to the surface of the Earth. In recent years, a few studies have been done regarding to the applications of the cosmic ray measurements and the correlations between the Earth's climate conditions and the cosmic ray fluxes [1,2,3]. Most of the particles, which reach to the surface of the Earth, are muons together with a small percentage of electrons, gammas, neutrons, etc. At Georgia State University, multiple cosmic ray particle detectors have been constructed to measure the fluxes and energy distributions of the secondary cosmic ray particles. In this presentation, we will briefly describe these prototype detectors and show the preliminary test results. Reference: [1] K.Borozdin, G.Hogan, C.Morris, W.Priedhorsky, A.Saunders, L.Shultz, M.Teasdale, Nature, Vol.422, 277 (2003). [2] L.V. Egorova, V. Ya Vovk, O.A. Troshichev, Journal of Atmospheric and Terrestrial Physics 62, 955-966 (2000). [3] Henrik Svensmark, Phy. Rev. Lett. 81, 5027 (1998). )

He, Xiaochun; Dayananda, Mathes

2010-02-01

179

Magnetic Experiments on the Cosmic Rays  

Microsoft Academic Search

BOTHE and Kolhörster1 wore the first to show that the cosmic rays manifest themselves to us as highly penetrating corpuscular rays. Direct experimental data on the nature as well as on the energy of these rays are still lacking; they might be obtained by experiments on the magnetic deflection if a sufficiently large and intense magnetic field could bo reached.

Bruno Rossi

1931-01-01

180

Cosmic-ray Helium Hardening  

NASA Astrophysics Data System (ADS)

Recent observations by the CREAM and ATIC-2 experiments suggest that (1) the spectrum of cosmic-ray (CR) helium is harder than that of CR protons below the knee energy, 1015eV, and (2) all CR spectra become hard at gsim1011eV nucleon-1. We propose a new idea, that higher energy CRs are generated in a more helium-rich region, to explain the hardening without introducing different sources for CR helium. The helium-to-proton ratio at ~100 TeV exceeds the Big Bang abundance Y = 0.25 by several times, and the different spectrum is not reproduced within the diffusive shock acceleration theory. We argue that CRs are produced in a chemically enriched region, such as a superbubble, and the outward-decreasing abundance naturally leads to the hard spectrum of CR helium if CRs escape from the supernova remnant shock in an energy-dependent way. We provide a simple analytical spectrum that also fits well the hardening due to the decreasing Mach number in the hot superbubble with ~106 K. Our model predicts hard and concave spectra for heavier CR elements.

Ohira, Yutaka; Ioka, Kunihito

2011-03-01

181

Cosmic Rays and Space Weather  

NASA Astrophysics Data System (ADS)

In this review-paper we consider following problems. 1. Cosmic rays (CR) as element of space weather 1.1. Influence of CR on the Earth's atmosphere and global climate change 1.2. Radia-tion hazard from galactic CR 1.3. Radiation hazard from solar CR 1.4. Radiation hazard from energetic particle precipitation from radiation belts 2. CR as tool for space weather forecasting 2.1. Forecasting of the part of global climate change caused by CR intensity variations 2.2. Forecasting of radiation hazard for aircrafts and spacecrafts caused by variations of galactic CR intensity 2.3. Forecasting of the radiation hazard from solar CR events by using on-line one-min ground neutron monitors network and satellite data 2.4. Forecasting of great magnetic storms hazard by using on-line one hour CR intensity data from ground based world-wide network of neutron monitors and muon telescopes 3. CR, space weather, and satellite anomalies 4. CR, space weather, and people health

Dorman, Lev

182

Cosmogenic gamma rays and the composition of cosmic rays  

SciTech Connect

We discuss the prospects of detecting the sources of ultrahigh energy (UHE) cosmic ray (CR) nuclei via their emission of cosmogenic {gamma} rays in the GeV to TeV energy range. These {gamma} rays result from electromagnetic cascades initiated by high energy photons, electrons, and positrons that are emitted by CRs during their propagation in the cosmic radiation background and are independent of the simultaneous emission of {gamma} rays in the vicinity of the source. The corresponding production power by UHE CR nuclei (with mass number A and charge Z) is dominated by pion photo production ({proportional_to}A) and Bethe-Heitler pair production ({proportional_to}Z{sup 2}). We show that the cosmogenic {gamma}-ray signal from a single steady UHE CR source is typically more robust with respect to variations of the source composition and injection spectrum than the accompanying signal of cosmogenic neutrinos. We study the diffuse emission from the sum of extragalactic CR sources as well as the point-source emission of the closest sources.

Ahlers, Markus [C. N. Yang Institute for Theoretical Physics, SUNY at Stony Brook, Stony Brook, New York 11794-3840 (United States); Salvado, Jordi [Departament d'Estructura i Constituents de la Materia and Institut de Ciencies del Cosmos, Universitat de Barcelona, 647 Diagonal, E-08028 Barcelona (Spain)

2011-10-15

183

Ultra-high-energy cosmic rays: the experimental situation  

NASA Astrophysics Data System (ADS)

The methods of detection of high-energy cosmic rays are briefly described and it is shown that results on the energy spectrum and arrival direction distribution obtained above 4×1019eV confound theoretical expectation. There is an urgent need for better statistics as only about 12 events above 1020eV have been detected and the limit to the energy which cosmic rays can reach is not known. The new, funded, instruments, the Pierre Auger Observatory and the Hi-Res fluorescence detector, are described and the plans for an ambitious satellite observatory (Airwatch/OWL) are outlined.

Watson, A. A.

2000-08-01

184

Search for superheavy elements in galactic cosmic rays  

NASA Astrophysics Data System (ADS)

The charge distribution of approximately 6000 nuclei with charge numbers above 55 in galactic cosmic rays has been obtained in the OLIMPIYA project. Three superheavy nuclei with the charge numbers in the range 105 < Z < 130 have been detected. The regression analysis has provided a more accurate estimate of the charge number of one of these nuclei (119{-6/+10} with a probability of 95%). Such nuclei should form stability islands. Their detection in nature confirms theoretical predictions and justifies efforts for their synthesis under terrestrial conditions. The model calculations performed in this work possibly can explain the results of some experiments on the investigation of the charge composition of cosmic rays in which particles with charge numbers in the range 94 < Z < 100 were detected (they cannot enter into the composition of primary cosmic radiation because their lifetime is very short). The calculations indicate that events with Z > 92 are due to the fragmentation of heavier nuclei from the stability island, rather than to methodical inaccuracies or fault of instruments. Several such events have been revealed. Thus, the track method makes it possible to obtain the results very important for understanding of the physical picture of the world. The results obtained within the OLIMPIYA project show that the study of tracks of galactic cosmic rays in olivine crystals from meteorites opens new capabilities for the investigation of fluxes and spectra in cosmic rays in the region of heavy and superheavy nuclei.

Bagulya, A. V.; Kashkarov, L. L.; Konovalova, N. S.; Okat'eva, N. M.; Polukhina, N. G.; Starkov, N. I.

2013-08-01

185

Cosmic Ray Acceleration in Astrophysical Environments  

NASA Astrophysics Data System (ADS)

Cosmic ray acceleration in astrophysical shocks is important. We discuss these shocks' properties and we perform Monte Carlo simulations studying their efficiency in accelerating particles (i.e. protons or electrons) up to very high energies with an application to astrophysical regions such as Super Novae, Active Galactic Nuclei hot spots and Gamma Ray Bursts. The efficiency of the acceleration mechanism at shocks varies in regard to the inclination of the magnetic field to the shock normal (e.g. subluminal shocks, superluminal shocks). This fact could have consequences to the contribution of the very high energy cosmic rays to the observed cosmic ray spectrum and the relevant neutrino and gamma-ray emission.

Meli, A.; Mastichiadis, A.

2008-01-01

186

THE INTERACTION OF COSMIC RAYS WITH DIFFUSE CLOUDS  

SciTech Connect

We study the change in cosmic-ray pressure, the change in cosmic-ray density, and the level of cosmic-ray-induced heating via Alfven-wave damping when cosmic rays move from a hot ionized plasma to a cool cloud embedded in that plasma. The general analysis method outlined here can apply to diffuse clouds in either the ionized interstellar medium or in galactic winds. We introduce a general-purpose model of cosmic-ray diffusion building upon the hydrodynamic approximation for cosmic rays (from McKenzie and Voelk and Breitschwerdt and collaborators). Our improved method self-consistently derives the cosmic-ray flux and diffusivity under the assumption that the streaming instability is the dominant mechanism for setting the cosmic-ray flux and diffusion. We find that, as expected, cosmic rays do not couple to gas within cool clouds (cosmic rays exert no forces inside of cool clouds), that the cosmic-ray density does not increase within clouds (it may decrease slightly in general, and decrease by an order of magnitude in some cases), and that cosmic-ray heating (via Alfven-wave damping and not collisional effects as for {approx}10 MeV cosmic rays) is only important under the conditions of relatively strong (10 {mu}G) magnetic fields or high cosmic-ray pressure ({approx}10{sup -11} erg cm{sup -3}).

Everett, John E.; Zweibel, Ellen G., E-mail: everett@physics.wisc.edu [Department of Astronomy, University of Wisconsin-Madison, Madison, WI 53706 (United States)

2011-10-01

187

Positron fraction in cosmic rays and models of cosmic-ray propagation  

SciTech Connect

The positron fraction observed by PAMELA and other experiments up to {approx}100 GeV is analyzed in terms of models of cosmic-ray propagation. It is shown that generically we expect the positron fraction to reach {approx}0.6 at energies of several TeV, and its energy dependence bears an intimate but subtle connection with that of the boron to carbon ratio in cosmic rays. The observed positron fraction can be fit in a model that assumes a significant fraction of the boron below {approx}10 GeV is generated through spallation of cosmic-ray nuclei in a cocoonlike region surrounding the sources, and the positrons of energy higher than a few GeV are almost exclusively generated through cosmic-ray interactions in the general interstellar medium. Such a model is consistent with the bounds on cosmic-ray anisotropies and other observations.

Cowsik, R.; Burch, B. [Physics Department and McDonnell Center for the Space Sciences, Washington University, St. Louis, Missouri 63130 (United States)

2010-07-15

188

Diffuse Galactic gamma rays from shock-accelerated cosmic rays.  

PubMed

A shock-accelerated particle flux is proportional to p(-s), where p is the particle momentum, follows from simple theoretical considerations of cosmic-ray acceleration at nonrelativistic shocks followed by rigidity-dependent escape into the Galactic halo. A flux of shock-accelerated cosmic-ray protons with s?2.8 provides an adequate fit to the Fermi Large Area Telescope ?-ray emission spectra of high-latitude and molecular cloud gas when uncertainties in nuclear production models are considered. A break in the spectrum of cosmic-ray protons claimed by Neronov, Semikoz, and Taylor [Phys. Rev. Lett. 108, 051105 (2012)] when fitting the ?-ray spectra of high-latitude molecular clouds is a consequence of using a cosmic-ray proton flux described by a power law in kinetic energy. PMID:23002818

Dermer, Charles D

2012-08-29

189

The galactic cosmic ray ionization rate  

PubMed Central

The chemistry that occurs in the interstellar medium in response to cosmic ray ionization is summarized, and a review of the ionization rates that have been derived from measurements of molecular abundances is presented. The successful detection of large abundances of H3+ in diffuse clouds and the recognition that dissociative recombination of H3+ is fast has led to an upward revision of the derived ionization rates. In dense clouds the molecular abundances are sensitive to the depletion of carbon monoxide, atomic oxygen, nitrogen, water, and metals and the presence of large molecules and grains. Measurements of the relative abundances of deuterated species provide information about the ion removal mechanisms, but uncertainties remain. The models, both of dense and diffuse clouds, that are used to interpret the observations may be seriously inadequate. Nevertheless, it appears that the ionization rates differ in dense and diffuse clouds and in the intercloud medium.

Dalgarno, A.

2006-01-01

190

Cosmic-ray ionization and chemistry: observations.  

NASA Astrophysics Data System (ADS)

The interaction between cosmic-rays and the dense regions of the ISM has important consequences on the physical and chemical state of the ISM. A major consequence is the ionisation of the ISM. I review here how the cosmic rays ionisation rate zeta is measured in the ISM and the values so far measured in ``average'' galactic clouds. I then discuss new observations in the direction of clouds spatially associated with bright gamma -rays TeV sources. The TeV emission is believed to be caused by the decay of pi 0 pions created by the irradiation of molecular clouds by large fluxes of cosmic rays just produced in SNRs. The measured zeta , enhanced by a factor 100 in at least one case, confirms this hypothesis. In addition, the high zeta causes a peculiar chemistry with the cloud possessing regions in Low and High Ionisation Phases (called LIP and HIP, in the literature), also briefly reviewed in this contribution.

Ceccarelli, C.

191

Some aspects of galactic cosmic ray acceleration  

NASA Astrophysics Data System (ADS)

I give a synopsis of two aspects of the Galactic Cosmic Ray (GCR) acceleration problem: the importance of the medium energy gamma-ray window, and several specific astrophysical sources which merit further investigation. NOTE: figures may be found in the on-line version only: atro-ph/0309758.

Butt, Yousaf Mahmood

2005-01-01

192

Terrestrial effects of high energy cosmic rays  

Microsoft Academic Search

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. 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

Dimitra Atri

2011-01-01

193

Cosmic Ray Interactions in Shielding Materials  

SciTech Connect

This document provides a detailed study of materials used to shield against the hadronic particles from cosmic ray showers at Earth’s surface. This work was motivated by the need for a shield that minimizes activation of the enriched germanium during transport for the MAJORANA collaboration. The materials suitable for cosmic-ray shield design are materials such as lead and iron that will stop the primary protons, and materials like polyethylene, borated polyethylene, concrete and water that will stop the induced neutrons. The interaction of the different cosmic-ray components at ground level (protons, neutrons, muons) with their wide energy range (from kilo-electron volts to giga-electron volts) is a complex calculation. Monte Carlo calculations have proven to be a suitable tool for the simulation of nucleon transport, including hadron interactions and radioactive isotope production. The industry standard Monte Carlo simulation tool, Geant4, was used for this study. The result of this study is the assertion that activation at Earth’s surface is a result of the neutronic and protonic components of the cosmic-ray shower. The best material to shield against these cosmic-ray components is iron, which has the best combination of primary shielding and minimal secondary neutron production.

Aguayo Navarrete, Estanislao; Kouzes, Richard T.; Ankney, Austin S.; Orrell, John L.; Berguson, Timothy J.; Troy, Meredith D.

2011-09-08

194

Measurement of the energy of horizontal cosmic ray muons  

NASA Astrophysics Data System (ADS)

An experiment in which the energy of cosmic ray muons is determined by measuring the electron positron pairs that they radiate off when passing through matter is described. The detector is a stack of lead converters interspersed with ionization chambers for particle detection. The chambers use as active medium the liquid tetra methyl silane (TMS). The radiated quanta initiate electromagnetic cascades in the lead and are recognized due to the characteristic shower development. The energy spectrum of horizontal muons is presented and from this the primary cosmic ray spectrum is deduced.

Gettert, Michael

1993-03-01

195

Some methods in high energy cosmic ray measurement  

NASA Astrophysics Data System (ADS)

Problems concerning ion chamber and emulsion detection techniques for high energy cosmic ray measurement are investigated. The calculation of the average energy actually deposited in an ion chamber by an ultra-high energy particle of large mass and charge is examined. A calculational scheme already applied successfully to particles of charge 1 is extended. Also, the calibration of a plate of plastic scintillator for measurement of the position of a cosmic ray shower passing through it is discussed. The method of calibration is to inject pulses of flight at known positions on the plate and record the responses of photomultiplier tubes at the corner of the plate.

Shand, J. B., Jr.

1980-10-01

196

Cosmic ray sun shadow in Soudan 2 underground muon flux.  

SciTech Connect

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. The authors 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.

Allison, W. W. M.; Alner, G. J.; Ayres, D. S.; Barrett, W. L.; Bode, C.; Fields, T. H.; Goodman, M. C.; Joffe-Minor, T.; Price, L. E.; Seidlein, R.; Soudan 2 Collaboration; Thron, J. L.

1999-06-23

197

Supernova Remnants, Cosmic Rays, and GLAST  

SciTech Connect

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)

2006-02-13

198

Supernova Remnants, Cosmic Rays, and GLAST  

ScienceCinema

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.

199

Monitor observations of cosmic rays on the Salyut-4 station  

Microsoft Academic Search

The characteristics of Salyut-4 observations of cosmic rays from December 1974 to July 1975 are examined. Particular attention is given to the latitude effect of the detected radiation; the longitude dependence at low and middle latitudes; attitude effects; absolute fluxes and energy spectra; the role of negative planetary magnetic anomalies; and the neutron component. The main conclusion of the study

V. I. Liagushin; N. A. Mamontova; B. M. Makhmudov; M. A. Saraeva; P. I. Shavrin; Iu. Iu. Iushkov

1984-01-01

200

Search for microwave emission from ultrahigh energy cosmic rays  

NASA Astrophysics Data System (ADS)

We present a search for microwave emission from air showers induced by ultrahigh energy cosmic rays with the microwave detection of air showers experiment. No events were found, ruling out a wide range of power flux and coherence of the putative emission, including those suggested by recent laboratory measurements.

Alvarez-Muñiz, J.; Berlin, A.; Bogdan, M.; Bohá?ová, M.; Bonifazi, C.; Carvalho, W. R., Jr.; de Mello Neto, J. R. T.; Facal San Luis, P.; Genat, J. F.; Hollon, N.; Mills, E.; Monasor, M.; Privitera, P.; Reyes, L. C.; Rouille d'Orfeuil, B.; Santos, E. M.; Wayne, S.; Williams, C.; Zas, E.; Zhou, J.

2012-09-01

201

The HEAO-3 Cosmic Ray Isotope spectrometer  

NASA Astrophysics Data System (ADS)

This paper describes the Cosmic Ray Isotope instrument launched aboard the HEAO-3 satellite on September 20, 1979. The primary purpose of the experiment is to measure the isotopic composition of cosmic ray nuclei from Be-7 to Fe-58 over the energy range 0.5 to 7 GeV/nucleon. In addition charge spectra will be measured between beryllium and tin over the energy range 0.5 to 25 GeV/nucleon. The charge and isotope abundances measured by the experiment provide essential information needed to further our understanding of the origin and propagation of high energy cosmic rays. The instrument consists of 5 Cerenkov counters, a 4 element neon flash tube hodoscope and a time-of-flight system. The determination of charge and energy for each particle is based on the multiple Cerenkov technique and the mass determination will be based upon a statistical analysis of particle trajectories in the geomagnetic field.

Bouffard, M.; Engelmann, J. J.; Koch, L.; Soutoul, A.; Lund, N.; Peters, B.; Rasmussen, I. L.

202

Positron Abundance in Galactic Cosmic Rays  

NASA Astrophysics Data System (ADS)

On 2000 August 25 from Lynn Lake, Manitoba, we conducted a balloon flight of the LEE/AESOP (Low Energy Electrons/Anti-Electron Sub Orbital Payload) payload to measure the spectrum of cosmic-ray electrons (resolved into negatrons and positrons) from 500 MeV to 3 GeV. Analysis of the data from that flight reveals a significant decrease in the cosmic-ray positron abundance from a level that remained relatively stable throughout the decade of the 1990s. Errors on the new determination are comparatively large due to the low particle fluxes at solar maximum. Nevertheless, the magnitude of the effect is consistent with predictions based on the assumption that cosmic-ray modulation effects with 22 yr periodicity are related simply and directly to charge sign and large-scale structure of the magnetic field embedded in the solar wind.

Clem, John M.; Evenson, Paul A.

2002-03-01

203

Bruno Rossi: Cosmic Ray Research 1929 - 1953  

NASA Astrophysics Data System (ADS)

Bruno Rossi, a fresh PhD from the University of Bologna, arrived in Florence in 1928. He was appointed assistant to Antonio Garbasso, professor of experimental physics. Garbosso at that time was Mayor of Florence. His days of physics were over which gave the young Rossi a freedom to follow any line of research. After some agonizing he came upon research in cosmic rays following the discovery that a large part of the cosmic rays were charged particles. Thus began a long period of creative research. Rossi had all the talents needed, a powerful intellect and the natural ability to construct apparatus that gave clear results for his experiments. I will give some examples of his many discoveries concerning the nature of cosmic rays.

Cronin, Jim

2012-03-01

204

Cosmic ray astrophysics and hadronic interactions  

NASA Astrophysics Data System (ADS)

Research in cosmic rays is now nearly a century old, but most of the fundamental questions in this field remain unanswered, on the other hand the perspectives of future studies in the next decade are very bright. New detectors will provide higher quality data in the entire energy range from 108 to 1020 eV (or more if particles of higher energy have non negligible fluxes), moreover cosmic ray astrophysics must now be considered, together with gamma, neutrino and gravitational wave astronomy, as one of the subfields of the high energy astrophysics, and using information from these four ``messengers'' there is the potential of a detailed understanding of the origin of the high energy radiation in the universe. High energy cosmic rays are measured indirectly observing the showers they generate in the atmosphere, and a correct and detailed interpretation of these measurements will require an improved understanding of the properties of hadronic interactions. The new collider experiments, and in particular the LHC project at CERN offer the unique possibility to perform measurements of great value for cosmic ray astrophysics. It is of great importance for cosmic research that this possibility is fully exploited with the appropriate instrumentation and analysis.

Lipari, Paolo

2003-07-01

205

Structure Formation Cosmic Rays: Identifying Observational Constraints  

NASA Astrophysics Data System (ADS)

Shocks that arise from baryonic in-fall and merger events during the structure formation are believed to be a source of cosmic rays. These "structure formation cosmic rays" (SFCRs) would essentially be primordial in composition, namely, mostly made of protons and alpha particles. However, very little is known about this population of cosmic rays. One way to test the level of its presence is to look at the products of hadronic reactions between SFCRs and the ISM. A perfect probe of these reactions would be 6Li. The rare isotope 6Li is produced only by cosmic rays, dominantly in alpha alpha rightarrow 6Li fusion reactions with the ISM helium. Consequently, this nuclide provides a unique diagnostic of the history of cosmic rays. Exactly because of this unique property is 6Li affected most by the presence of an additional cosmic ray population. In turn, this could have profound consequences for the Big-Bang nucleosynthesis: cosmic rays created during cosmic structure formation would lead to pre-Galactic Li production, which would act as a "contaminant" to the primordial 7Li content of metal-poor halo stars. Given the already existing problem of establishing the concordance between 7Li observed in halo stars and primordial 7Li as predicted by the WMAP, it is crucial to set limits to the level of this "contamination". However, the history of SFCRs is not very well known. Thus we propose a few model- independent ways of testing the SFCR species and their history, as well as the existing lithium problem: 1) we establish the connection between gamma-ray and 6Li production, which enables us to place constraints on the SFCR-made lithium by using the observed Extragalactic Gamma-Ray Background (EGRB); 2) we propose a new site for testing the primordial and SFCR-made lithium, namely, low-metalicity High-Velocity Clouds (HVCs), which retain the pre-Galactic composition without any significant depletion. Although using one method alone may not give us strong constraints, using them in concert will shed a new light on the SFCR population and possibly give some answers about the pressing lithium problem.

Prodanovic, T.; Fields, B. D.

2005-06-01

206

Cosmic-ray Muon Flux In Belgrade  

SciTech Connect

Two identical plastic scintillator detectors, of prismatic shape (50x23x5)cm similar to NE102, were used for continuous monitoring of cosmic-ray intensity. Muon {delta}E spectra have been taken at five minute intervals, simultaneously from the detector situated on the ground level and from the second one at the depth of 25 m.w.e in the low-level underground laboratory. Sum of all the spectra for the years 2002-2004 has been used to determine the cosmic-ray muon flux at the ground level and in the underground laboratory.

Banjanac, R.; Dragic, A.; Jokovic, D.; Udovicic, V. [Institute of Physics, University of Belgrade, Belgrade (Serbia and Montenegro); Puzovic, J.; Anicin, I. [Faculty of Physics, University of Belgrade, Belgrade (Serbia and Montenegro)

2007-04-23

207

Cosmic Rays, Carbon Dioxide, and Climate  

NASA Astrophysics Data System (ADS)

Several recent papers have applied correlation analysis to climate-related time series in the hope of finding evidence for causal relationships. For a critical discussion of correlations between solar variability, cosmic rays, and cloud cover, see Laut [2003]. A prominent new example is a paper by Shaviv and Veizer [2003], which claims that fluctuations in cosmic ray flux reaching the Earth can explain 66% of the temperature variance over the past 520 m.y., and that the sensitivity of climate to a doubling of CO2 is less than previously estimated.

Rahmstorf, Stefan; Archer, David; Ebel, Denton S.; Eugster, Otto; Jouzel, Jean; Maraun, Douglas; Neu, Urs; Schmidt, Gavin A.; Severinghaus, Jeff; Weaver, Andrew J.; Zachos, Jim

2004-01-01

208

Energy loss measurement of cosmic ray muons  

NASA Astrophysics Data System (ADS)

Measurements of energy losses of high energy cosmic ray muons in an ionization chamber are presented. The chamber consists of 16 single gap layers, and the liquid tetra methyl silane (TMS) was used as active medium. The absolute energy loss and the relativistic rise were measured and compared with theoretical calculations. The importance of the measurements within the framework of the cosmic ray experiment KASCADE (German acronym for Karlsruhe Shower Core and Array Detector) are discussed, especially with respect to energy calibration of hadrons and high energy muons above 1 TeV.

Unger, Joseph

1993-02-01

209

Cosmic-ray Muon Flux In Belgrade  

NASA Astrophysics Data System (ADS)

Two identical plastic scintillator detectors, of prismatic shape (50×23×5)cm similar to NE102, were used for continuous monitoring of cosmic-ray intensity. Muon ?E spectra have been taken at five minute intervals, simultaneously from the detector situated on the ground level and from the second one at the depth of 25 m.w.e in the low-level underground laboratory. Sum of all the spectra for the years 2002-2004 has been used to determine the cosmic-ray muon flux at the ground level and in the underground laboratory.

Banjanac, R.; Dragi?, A.; Jokovi?, D.; Udovi?i?, V.; Puzovi?, J.; Ani?in, I.

2007-04-01

210

Cosmic Ray Anisotropy with the KASCADE Experiment  

NASA Astrophysics Data System (ADS)

Anisotropies in the arrival directions of cosmic rays reflect their source distribution and propagation properties. In the presented analysis extensive air shower measurements with KASCADE are analyzed with respect to large and small scale anisotropies. The resulting upper limits on large scale anisotropy amplitudes of 10-3 to 10-2 restrict the parameter space of several propagation models. No cosmic ray point sources could be found in a sky survey of the northern hemisphere. Typical upper flux limits for point sources are around 10-10 m-2s-1.

Maier, Gernot; Antoni, T.; Apel, W. D.; Badea, A. F.; Bekk, K.; Bercuci, A.; Blümer, H.; Bozdog, H.; Brancus, I. M.; Büttner, C.; Chilingarian, A.; Daumiller, K.; Doll, P.; Engel, R.; Engler, J.; Feßler, F.; Gils, H. J.; Glasstetter, R.; Haungs, A.; Heck, D.; Hörandel, J. R.; Kampert, K.-H.; Klages, H. O.; Mathes, H. J.; Mayer, H. J.; Milke, J.; Müller, M.; Obenland, R.; Oehlschläger, J.; Ostapchenko, S.; Petcu, M.; Rebel, H.; Risse, A.; Risse, M.; Roth, M.; Schatz, G.; Schieler, H.; Scholz, J.; Thouw, T.; Ulrich, H.; van Buren, J.; Vardanyan, A.; Weindl, A.; Wochele, J.; Zabierowski, J.

211

Using GEANT4 to model the photonic component of cosmic ray air showers.  

NASA Astrophysics Data System (ADS)

The CREST (Cosmic Ray Electron Synchrotron Telescope) project uses a high altitude balloon to carry a cosmic ray detector into Earth's upper atmosphere. The purpose of the project is to understand more about the local galactic sources that produce high-energy electron cosmic rays by detecting the linear pattern of synchrotron radiation emitted as the electrons are diverted by Earth's magnetic field. While this pattern is very distinct, there is a possibility that a similar pattern could be mimicked by cosmic ray air showers, which also produce temporally and spatially correlated photons. To estimate the background event rate due to air showers at balloon altitudes, GEANT4 is used to simulate cosmic ray air showers. The simulation entails modeling the composition and structure of earth's atmosphere by representing it as hundreds of variable density layers, along with reproducing the cosmic ray incident energy spectrum and composition. Information about photons is recorded as they pass through different depths in the atmosphere.

Bench, J.; Nutter, S.

2006-04-01

212

The Mystery of Ultra-High Energy Cosmic Rays  

SciTech Connect

Cosmic rays with energies well above 1019 eV are messengers of an unknown extremely high-energy universe. The current state and future prospects of ultra high energy cosmic ray physics are briefly reviewed.

Olinto, Angela V. [Department of Astronomy and Astrophysics, EFI, KICP, University of Chicago, 5640 S. Ellis Ave, Chicago, IL 60637, Chicago (United States)

2006-07-11

213

Elemental Composition and Energy Spectra of Galactic Cosmic Rays.  

National Technical Information Service (NTIS)

A brief review is presented of the major features of the elemental composition and energy spectra of galactic cosmic rays. The requirements for phenomenological models of cosmic ray composition and energy spectra are discussed, and possible improvements t...

R. A. Mewaldt

1988-01-01

214

Fermi-LAT and cosmic rays  

NASA Astrophysics Data System (ADS)

The Fermi Gamma-ray Space Telescope was launched on June 11, 2008; within days of full activation, the first Large Area Telescope (LAT) all-sky map of the sky revealed new high-energy sources and since the start of science operations in August 2008, the LAT has been observing the entire sky once every three hours. These observations have revealed more than 1,873 high-energy gamma-ray sources, including several classes of active galaxies, pulsars, pulsar wind nebulae, supernova remnants, binary sources, high-energy gamma-ray bursts, a nova, the Sun and most recently Terrestrial Gamma Ray Flashes. Fermi-LAT has mapped the Galactic diffuse gamma-ray emission created by cosmic-ray interactions in the interstellar medium, and measured the spectrum of isotropic emission. In addition, Fermi-LAT is a capable detector of high-energy electrons. It has measured electrons in cosmic rays with unprecedented accuracy and used Earth's shadow and geomagnetic field to measure cosmic ray positrons. I will give an overview of the latest results of the Fermi mission.

Michelson, Peter

2012-07-01

215

Microphysics of Cosmic Ray Driven Plasma Instabilities  

NASA Astrophysics Data System (ADS)

Energetic nonthermal particles (cosmic rays, CRs) are accelerated in supernova remnants, relativistic jets and other astrophysical objects. The CR energy density is typically comparable with that of the thermal components and magnetic fields. In this review we discuss mechanisms of magnetic field amplification due to instabilities induced by CRs. We derive CR kinetic and magnetohydrodynamic equations that govern cosmic plasma systems comprising the thermal background plasma, comic rays and fluctuating magnetic fields to study CR-driven instabilities. Both resonant and non-resonant instabilities are reviewed, including the Bell short-wavelength instability, and the firehose instability. Special attention is paid to the longwavelength instabilities driven by the CR current and pressure gradient. The helicity production by the CR current-driven instabilities is discussed in connection with the dynamo mechanisms of cosmic magnetic field amplification.

Bykov, A. M.; Brandenburg, A.; Malkov, M. A.; Osipov, S. M.

2013-05-01

216

Charge Sign Dependence in Cosmic Ray Solar Modulation  

Microsoft Academic Search

The steady flux of cosmic rays entering the heliosphere provides a unique probe for studying the magnetic fields carried by the solar wind. Fluctuations in these magnetic fields produce an anti-correlation between cosmic ray intensities observed at Earth and the level of solar activity (solar modulation). Cosmic ray electrons and nuclei respond differently to solar modulation, with the differences being

John Clem; P. Evenson

2009-01-01

217

Solar-Cosmic-Ray-Produced Nuclides in Extraterrestrial Matter  

Microsoft Academic Search

There are two main types of cosmic rays that have sufficient energy to induce nuclear reactions -- the galactic cosmic rays (GCR) and solar cosmic rays (also called solar energetic particles). Both types of particles can have production rates and production ratios in the small objects often found in cold and hot deserts that are different from those seen for

Robert C. Reedy

2000-01-01

218

Testing the cosmic ray-lightning connection hypothesis  

Microsoft Academic Search

The proposed dependence of atmospheric electrical properties on the ionizing influence of cosmic rays has resulted in numerous attempts to obtain convincing correlations. While most of the studies remain largely theoretical, a few results indicate that there is a plausible link between lightning activity and cosmic ray ionization. Using global lightning and assimilated cosmic ray data, the present work suggests

Ogbonnaya Okike; Andrew B. Collier

2011-01-01

219

Gamma rays from cosmic rays in supernova remnants  

NASA Astrophysics Data System (ADS)

Context. Cosmic rays are thought to be accelerated at supernova remnant (SNR) shocks, but obtaining conclusive evidence for this hypothesis is difficult. Aims: New data from ground-based ?-ray telescopes and the Large Area Telescope on the Fermi Gamma-ray Space Telescope are used to test this hypothesis. A simple model for ?-ray production efficiency is compared with measured ?-ray luminosities of SNRs, and the GeV to TeV fluxes ratios of SNRs are examined for correlations with SNR ages. Methods: The supernova explosion is modeled as an expanding spherical shell of material that sweeps up matter from the surrounding interstellar medium (ISM). The accumulated kinetic energy of the shell, which provides the energy available for nonthermal particle acceleration, changes when matter is swept up from the ISM and the SNR shell decelerates. A fraction of this energy is assumed to be converted into the energy of cosmic-ray electrons or protons. Three different particle radiation processes - nuclear pion-production interactions, nonthermal electron bremsstrahlung, and Compton scattering - are considered. Results: The efficiencies for ?-ray production by these three processes are compared with ?-ray luminosities of SNRs. Our results suggest that SNRs become less ?-ray luminous at ?104 yr, and are consistent with the hypothesis that supernova remnants accelerate cosmic rays with an efficiency of ?10% for the dissipation of kinetic energy into nonthermal cosmic rays. Weak evidence for an increasing GeV to TeV flux ratio with SNR age is found.

Dermer, C. D.; Powale, G.

2013-05-01

220

The Production of Cosmic Gamma Rays in Interstellar and Intergalactic Cosmic-Ray Collisions. Iv: Gamma-Ray Production from Cosmic Proton-Antiproton Interactions  

Microsoft Academic Search

Various cosmological situations are discussed in which the annihilation of anti-matter will produce cosmic gamma-rays. An upper limit is placed on the amount of cosmic matter-antimatter interaction consistent with recent cosmic gamma-ray observation It is shown that the production of mesons other than pions have little effect on the annihilation gamma-rays spectrum. It is also shown that gamma rays arising

F. W. Stecker

1967-01-01

221

Detecting ultra-high energy cosmic rays from space with unprecedented acceptance: objectives and design of the JEM-EUSO mission  

NASA Astrophysics Data System (ADS)

The Extreme Universe Space Observatory on the Japanese Experiment Module (JEM-EUSO) of the International Space Station (ISS) is the first mission that will study from space Ultra High-Energy Cosmic Rays (UHECR). JEM-EUSO will observe Extensive Air Showers (EAS) produced by UHECRs traversing the Earth's atmosphere from above. For each event, the detector will make accurate measurements of the energy, arrival direction and nature of the primary particle using a target volume far greater than what is achievable from ground. The corresponding increase in statistics will help to clarify the origin and sources of UHECRs as well as the environment traversed during production and propagation. Possibly this will bring new light onto particle physics mechanisms operating at energies well beyond those achievable by man-made accelerators. The spectrum of scientific goals of the JEM-EUSO mission includes as exploratory objectives the detection of high-energy gamma rays and neutrinos, the study of cosmic magnetic fields, and tests of relativity and quantum gravity effects at extreme energies. In parallel JEM-EUSO will systematically perform observation of the surface of the Earth in the infra-red and ultra-violet ranges, studying also atmospheric phenomena (Transient Luminous Effects). The apparatus is a 2 t detector using Fresnel-based optics to focus the UV-light from EAS on a focal surface composed of about 6 000~multianode photomultipliers for a total of ~3 · 105 channels. A multi-layer parallel architecture has been devised to handle the data flow and select valid triggers, reducing it to a rate compatible with downlink constraints. Each processing level filters the event with increasingly complex algorithms using ASICs, FPGAs and DSPs in this order to reject spurious triggers and reduce the data rate.

Casolino, M.; Adams, J. H.; Bertaina, M. E.; Christl, M. J.; Ebisuzaki, T.; Gorodetzky, P.; Hachisu, Y.; Kajino, F.; Kawasaki, Y.; Medina-Tanco, G.; Miyamoto, H.; Ohomori, H.; Parizot, E.; Park, I.; Picozza, P.; Sakaki, N.; Santangelo, A.; Shinozaki, K.; Takizawa, Y.; Tsuno, K.; JEM-EUSO Collaboration

2011-10-01

222

Cosmic ray physics from low to extreme energies: status and perspectives  

Microsoft Academic Search

Since their discovery, almost one century ago, cosmic rays provide a powerful tool to investigate phenomena covering both astrophysical and fundamental physics issues. The detection of cosmic rays from low to extreme energies is potentially linked to some of the most intriguing and still unsolved questions of physics and cosmology. Among them, are the nature of the dark matter, the

M. T. Brunetti; R. Battiston; P. Blasi; D. de Marco; P. Lipari; B. Sacco

2004-01-01

223

Cosmic ray physics from low to extreme energies: Status and perspectives  

Microsoft Academic Search

Since their discovery, almost one century ago, cosmic rays provide a powerful tool to investigate phenomena covering both astrophysical and fundamental physics issues. The detection of cosmic rays from low to extreme energies is potentially linked to some of the most intriguing and still unsolved questions of physics and cosmology. Among them, are the nature of the dark matter, the

R. Battiston; P. Blasi; M. T. Brunetti; D. De Marco; P. Lipari; B. Sacco; A. Santangelo

2006-01-01

224

Nature of Cosmic gamma Ray Bursts.  

National Technical Information Service (NTIS)

The nature of cosmic gamma ray burst is studied. The sources of the observed gamma bursts are supposed to be presented by the two populations of galactic objects, namely: the old neutron stars concentrated in the galactic disk; and the old degenerated dwa...

N. I. Shakura N. N. Shakura

1990-01-01

225

Isotropic Modulation of Galactic Cosmic Rays.  

National Technical Information Service (NTIS)

Phenomena associated with cosmic ray isotropic modulation are reviewed. Both short-term and long-term variations are considered. For the most part, neutrino monitor data is cited. Results are used to explain solar activity cycle-related modulation fluctua...

N. Iucci

1979-01-01

226

Early cosmic ray research in Italy  

NASA Astrophysics Data System (ADS)

The contribution of Italian scientists and Italian institutions to the study of cosmic rays will be covered from the precursor experiments in 1908-1910 up to the identification of the muon by Conversi, Pancini and Piccioni in 1945-1946 experiments.

Spillantini, Piero

2013-02-01

227

Cosmic ray transport in strong turbulence  

Microsoft Academic Search

Recently, several non-linear theories for cosmic ray transport have been proposed to achieve agreement with numerical test particle simulations. Some of these theories, which can be seen as an improvement of quasi-linear theory, agree with simulations. Because recent reports have shown that the perpendicular mean free path could be larger than the parallel mean free path, the assumption of strong

A. Shalchi

2005-01-01

228

Heliosphere Changes Affect Cosmic Ray Penetration  

NASA Video Gallery

The changes in the size of our solar system’s boundaries also cause changes to the galactic cosmic rays that enter the solar system. Although these boundaries do a good job of deflecting the majority of harmful galactic radiation, some fraction of this galactic radiation always makes it into the solar system.

Holly Zell

2010-09-28

229

Green River Community College Cosmic Ray Detector  

Microsoft Academic Search

The Washington Area Large scale Time coincidence Array (WALTA) researches high-energy cosmic ray and has placed particle detector arrays around the Seattle area to increase the accuracy of muon information. Green River Community College is one of the schools in collaboration with WALTA and offers its students under-graduate research by working with the particle detector arrays, data collecting and reporting.

Andrea Roma; Crissy Harrington; Mirela Isic; Andrew Adams; Ron Draper

2008-01-01

230

Life Extinctions by Cosmic Ray Jets  

Microsoft Academic Search

High energy cosmic ray jets from nearby mergers or accretion induced collapse of neutron stars that hit the atmosphere can produce lethal fluxes of atmospheric muons at ground level, underground and underwater, destroy the ozone layer, and radioactivate the environment. They could have caused some of the massive life extinctions on planet Earth in the past 570 Myr. Biological mutations

Arnon Dar; Ari Laor; Nir J. Shaviv

1998-01-01

231

The Cosmic Gamma-Ray Bursts  

Microsoft Academic Search

Cosmic gamma-ray bursts are one of the great frontiers of astrophysics today. They are a playground of relativists and observers alike. They may teach us about the death of stars and the birth of black holes, the physics in extreme conditions, and help us probe star formation in the distant and obscured universe. In this review we summarise some of

S. G. Djorgovski; D. A. Frail; S. R. Kulkarni; R. Sari; J. S. Bloom; T. J. Galama; F. A. Harrison; P. A. Price; D. Fox; D. E. Reichart; S. Yost; E. Berger; A. Diercks; R. Goodrich; F. Chaffee

2002-01-01

232

Numerical likelihood analysis of cosmic ray anisotropies  

SciTech Connect

A numerical likelihood approach to the determination of cosmic ray anisotropies is presented which offers many advantages over other approaches. It allows a wide range of statistically meaningful hypotheses to be compared even when full sky coverage is unavailable, can be readily extended in order to include measurement errors, and makes maximum unbiased use of all available information.

Carlos Hojvat et al.

2003-07-02

233

Modeling galactic cosmic rays at lunar orbit  

Microsoft Academic Search

High-energy particles such as galactic cosmic rays (GCRs) and solar energetic particles (SEPs) have sufficient kinetic energy to produce undesirable biological effects in astronauts as well as environmental effects on spacecraft electronic systems. In low Earth orbit, such radiation effects are minimized owing to the strong geomagnetic cutoff from Earth's internal magnetic field. However, the risks increase at higher altitudes

Chia-Lin Huang; Harlan Spence; Brian Kress; Simon Shepherd

2008-01-01

234

Cosmic ray muons in the deep ocean  

Microsoft Academic Search

A measurement of cosmic ray muon flux was obtained at ocean depths ranging from 2 km to 4 km at 500 m intervals off the West Coast of the Big Island of Hawaii. A brief description of the experiment and the results will be presented in this paper.

J. Babson; B. Barish; R. Becker-Szenzy; H. Bradner; R. Cady; J. Clem; S. T. Dye; J. Gaidos; P. Gorham; P. K. F. Grieder; T. Kitamura; W. Kropp; J. Learned; S. Matsuno; R. March; K. Mitsui; D. O'Conner; Y. Ohashi; A. Okada; V. Peterson; L. Price; F. Reines; A. Roberts; C. Roos; H. Sobel; V. Stenger; M. Webster; C. Wilson

1990-01-01

235

Study of the primary cosmic ray mass composition using gamma rays  

Microsoft Academic Search

Context: The gamma rays detected by passive balloon-borne emulsion chambers in the stratosphere give additional information on primary cosmic ray composition and allow indirect testing of the conclusions based on the study of the primary particle tracks. Aims: We search for a consistent view of the balloon experiments with traditional calorimeter-type emulsion conducted at various atmospheric depths in the stratosphere.

V. Kopenkin; Y. Fujimoto

2007-01-01

236

Isotopic Composition of Cosmic Rays:. Results from the Cosmic Ray Isotope Spectrometer on the Ace Spacecraft  

NASA Astrophysics Data System (ADS)

Over the past seven years the Cosmic Ray Isotope Spectrometer (CRIS) on the ACE spacecraft has returned data with an unprecedented combination of excellent mass resolution and high statistics, describing the isotopic composition of elements from lithium through nickel in the energy interval ~ 50 to 500 MeV/nucleon. These data have demonstrated: * The time between nucleosynthesis and acceleration of the cosmic-ray nuclei is at least 105 years. The supernova in which nucleosynthesis takes place is thus not the same supernova that accelerates a heavy nucleus to cosmic-ray energy. * The mean confinement time of cosmic rays in the Galaxy is 15 Myr. * The isotopic composition of the cosmic-ray source is remarkably similar to that of solar system. The deviations that are observed, particularly at 22Ne and 58Fe, are consistent with a model in which the cosmic-ray source is OB associations in which the interstellar medium has solar-system composition enriched by roughly 20% admixture of ejecta from Wolf-Rayet stars and supernovae. * Cosmic-ray secondaries that decay only by electron capture provide direct evidence for energy loss of cosmic rays as they penetrate the solar system. This invited overview paper at ECRS 19 was largely the same as an invited paper presented a month earlier at the 8th Nuclei in the Cosmos Conference in Vancouver. The proceedings of that conference will be published shortly by Elsevier as a special edition of Nuclear Physics A. For further summary of results from CRIS, the reader is referred to URL <> and links on that page to CRIS and to Science News.

Israel, M. H.

237

Development of cosmic x-ray polarimeter  

Microsoft Academic Search

We present a performance study of a cosmic X-ray polarimeter which is based on the photoelectric effect in gas, and sensitive to a few to 30 keV range. In our polarimeter, the key device would be the 50 mum pitch Gas Electron Multiplier (GEM). We have evaluated the modulation factor using highly polarized X-ray, provided by a synchrotron accelerator. In

Asami Hayato; Toru Tamagawa; Naoko Tsunoda; Shigehira Hashimoto; Masao Miyamoto; Mitsuhiro Kohama; Fuyuki Tokanai; Hideki Hamagaki; Masahide Inuzuka; Hiromasa Miyasaka; Ikuya Sakurai; Kazuo Makishima

2006-01-01

238

In Search of Cosmic Rays: A Student Physics Project Aimed at Finding the Origin of Cosmic Rays.  

ERIC Educational Resources Information Center

Describes an ongoing project, the Cosmic Ray Observatory Project (CROP), being conducted by the University of Nebraska in partnership with several high schools. Each school group has installed cosmic ray detectors, and initial activities have included calibrating equipment, gathering preliminary data, and learning about cosmic ray showers. Aims to…

Antonelli, Jamie; Mahoney, Sean; Streich, Derek; Liebl, Michael

2001-01-01

239

Three-dimensional cosmic ray anisotropy in interplanetary space. III. Origin of cosmic ray solar semidiurnal variation  

Microsoft Academic Search

Annual modulation of cosmic-ray daily variation, observed by ion-; chambers at Cheltenhan and Christchurch, were studied in order to determaine the ; anisotropy responsible for the solar semi-diurnal variation of cosmic rays. So ; far, two hypotheses have beenproposed for the explanation of the anisotropy. One ; is called the density gradient hypothesis which assumes the existence of cosmic-; ray

K. Nagashima; H. Ueno; K. Fujimoto; Z. Fujii; I. Kondo

1972-01-01

240

Supernova Remnants as the Sources of Galactic Cosmic Rays  

NASA Astrophysics Data System (ADS)

The origin of cosmic rays holds still many mysteries hundred years after they were first discovered. Supernova remnants have for long been the most likely sources of Galactic cosmic rays. I discuss here some recent evidence that suggests that supernova remnants can indeed efficiently accelerate cosmic rays. For this conference devoted to the Astronomical Institute Utrecht I put the emphasis on work that was done in my group, but placed in a broader context: efficient cosmic-ray acceleration and the implications for cosmic-ray escape, synchrotron radiation and the evidence for magnetic-field amplification, potential X-ray synchrotron emission from cosmic-ray precursors, and I conclude with the implications of cosmic-ray escape for a Type Ia remnant like Tycho and a core-collapse remnant like Cas A.

Vink, J.

2013-01-01

241

Cosmic-Ray Transport and Interaction with Shocks  

NASA Astrophysics Data System (ADS)

This paper reviews selected topics in cosmic-ray transport in the heliosphere, as well as recent insights on the interaction of cosmic rays with shocks. Topics include: (a) recent observations suggesting very long inferred scattering mean-free paths of cosmic rays, (b) recent insights into the diffusion of cosmic rays normal to a magnetic field, (c) the physics of super-diffusion and sub-diffusion, and (e) the interaction of cosmic rays with shocks moving through large-scale irregular magnetic fields.

Giacalone, Joe

2013-06-01

242

Measurement of Cosmic-Ray TeV Electrons  

NASA Astrophysics Data System (ADS)

The Cosmic Ray Electron Synchrotron Telescope (CREST) high-altitude balloon experiment is a pathfinding effort to detect for the first time multi-TeV cosmic-ray electrons. At these energies distant sources will not contribute to the local electron spectrum due to the strong energy losses of the electrons and thus TeV observations will reflect the distribution and abundance of nearby acceleration sites. CREST will detect electrons indirectly by measuring the characteristic synchrotron photons generated in the Earth's magnetic field. The instrument consist of an array of 1024 BaF2 crystals viewed by photomultiplier tubes surrounded by a hermetic scintillator shield. Since the primary electron itself need not traverse the payload, an effective detection area is achieved that is several times the nominal 6.4 m2 instrument. CREST is scheduled to fly in a long duration circumpolar orbit over Antarctica during the 2011-12 season.

Schubnell, Michael; Anderson, T.; Bower, C.; Coutu, S.; Gennaro, J.; Geske, M.; Mueller, D.; Musser, J.; Nutter, S.; Park, N.; Tarle, G.; Wakely, S.

2011-09-01

243

Acceleration of cosmic rays and gamma-ray emission from supernova remnants in the Galaxy  

NASA Astrophysics Data System (ADS)

Galactic cosmic rays are believed to be accelerated at supernova remnant shocks. Though very popular and robust, this conjecture still needs a conclusive proof. The strongest support to this idea is probably the fact that supernova remnants are observed in gamma-rays, which are indeed expected as the result of the hadronic interactions between the cosmic rays accelerated at the shock and the ambient gas. However, also leptonic processes can, in most cases, explain the observed gamma-ray emission. This implies that the detections in gamma-rays do not necessarily mean that supernova remnants accelerate cosmic ray protons. To overcome this degeneracy, the multiwavelength emission (from radio to gamma-rays) from individual supernova remnants has been studied and in a few cases it has been possible to ascribe the gamma-ray emission to one of the two processes (hadronic or leptonic). Here, we adopt a different approach and, instead of a case-by-case study we aim for a population study and we compute the number of supernova remnants which are expected to be seen in TeV gamma-rays above a given flux under the assumption that these objects indeed are the sources of cosmic rays. The predictions found here match well with current observational results, thus providing a novel consistency check for the supernova remnant paradigm for the origin of Galactic cosmic rays. Moreover, hints are presented for the fact that particle spectra significantly steeper than E-2 are produced at supernova remnants. Finally, we expect that several of the supernova remnants detected by HESS in the survey of the Galactic plane should exhibit a gamma-ray emission dominated by hadronic processes (i.e. neutral-pion decay). The fraction of the detected remnants for which the leptonic emission dominates over the hadronic one depends on the assumed values of the physical parameters (especially the magnetic field strength at the shock) and can be as high as roughly a half.

Cristofari, P.; Gabici, S.; Casanova, S.; Terrier, R.; Parizot, E.

2013-10-01

244

Cosmic ray nonlinear processes in gamma-ray sources  

Microsoft Academic Search

The interaction of cosmic ray (CR) particles (protons, nuclei and electrons) with matter determine the main processes of high energy gamma-ray (GR) generation through neutral pions decay and bremsstrahlung emission. On the other side, the acceleration and propagation of these particles is mainly determined by nonlinear processes of CR in GR sources: the influence of CR pressure on plasma dynamics;

L. I. Dorman

1996-01-01

245

Determination and study of the cosmic-ray composition above 100 TeV  

SciTech Connect

This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The goal of this project was to develop a new technique using ground-based measurements to determine the cosmic-ray composition at energies around 10{sup 15} eV (the knee in the cosmic-ray spectrum). Cosmic rays are high-energy nuclei that continuously bombard the earth. Though cosmic rays were first detected in the 1870s it wasn`t until 1915 that their cosmic origin was established. At present, the authors still do not know the source of cosmic rays. At energies above 50 TeV (1 TeV = 1 trillion electron-volts) they do not know the composition of the cosmic rays. At about 5 PeV (1PeV = 10{sup 15} eV) the cosmic ray spectrum steepens. Knowledge of the composition above and below this point can help determine the origin of cosmic rays.

Sinnis, G.; Haines, T.J.; Hoffman, C.M. [and others

1998-11-01

246

Cosmic-ray Exposure Ages of Meteorites  

NASA Astrophysics Data System (ADS)

The classic idea of a cosmic-ray exposure (CRE) age for a meteorite is based on a simple but useful picture of meteorite evolution, the one-stage irradiation model. The precursor rock starts out on a parent body, buried under a mantle of material many meters thick that screens out cosmic rays. At a time ti, a collision excavates a precursor rock - a "meteoroid." The newly liberated meteoroid, now fully exposed to cosmic rays, orbits the Sun until a time tf, when it strikes the Earth, where the overlying blanket of air (and possibly of water or ice) again shuts out almost all cosmic rays (cf. Masarik and Reedy, 1995). The quantity tf-ti is called the CRE age, t. To obtain the CRE age of a meteorite, we measure the concentrations in it of one or more cosmogenic nuclides (Table 1), which are nuclides that cosmic rays produce by inducing nuclear reactions. Many shorter-lived radionuclides excluded from Table 1 such as 22Na (t1/2=2.6 yr) and 60Co (t1/2=5.27 yr) can also furnish valuable information, but can be measured only in meteorites that fell within the last few half-lives of those nuclides (see, e.g., Leya et al. (2001) and references therein). Table 1. Cosmogenic nuclides used for calculating exposure ages NuclideHalf-lifea (Myr) Radionuclides 14C0.005730 59Ni0.076 41Ca0.1034 81Kr0.229 36Cl0.301 26Al0.717 10Be1.51 53Mn3.74 129I15.7 Stable nuclides 3He 21Ne 38Ar 83Kr 126Xe a http://www2.bnl.gov/ton. CRE ages have implications for several interrelated questions. From how many different parent bodies do meteorites come? How well do meteorites represent the population of the asteroid belt? How many distinct collisions on each parent body have created the known meteorites of each type? How often do asteroids collide? How big and how energetic were the collisions that produced meteoroids? What factors control the CRE age of a meteorite and how do meteoroid orbits evolve through time? We will touch on these questions below as we examine the data.By 1975, the CRE ages of hundreds of meteorites had been estimated from noble gas measurements. Histograms of the CRE age distributions pointed to several important observations.(i) The CRE ages of meteorites increase in the order stones detection limits for cosmogenic nuclides and

Herzog, G. F.

2003-12-01

247

Gamma ray bursts from superconducting cosmic strings  

SciTech Connect

Cusps of superconducting strings can serve as GRB engines. A powerful beamed pulse of electromagnetic radiation from a cusp produces a jet of accelerated particles, whose propagation is terminated by the shock responsible for GRB. A single free parameter, the string scale of symmetry breaking {eta}{approx}10{sup 14} GeV, together with reasonable assumptions about the magnitude of cosmic magnetic fields and the fraction of volume that they occupy, explains the GRB rate, duration, and fluence, as well as the observed ranges of these quantities. The wiggles on the string can drive the short-time structures of GRB. This model predicts that GRBs are accompanied by strong bursts of gravitational radiation which should be detectable by LIGO, VIRGO, and LISA detectors. Another prediction is the diffuse x- and gamma-ray radiation at 8 MeV--100 GeV with a spectrum and flux comparable to the observed. The weakness of the model is the prediction of too low a rate of GRBs from galaxies, as compared with observations. This suggests that either the capture rate of string loops by galaxies is underestimated in our model or that GRBs from cusps are responsible for only a subset of the observed GRBs not associated with galaxies.

Berezinsky, V.; Hnatyk, B.; Vilenkin, A.

2001-08-15

248

Geant Simulation of Cosmic Ray Veto System  

NASA Astrophysics Data System (ADS)

The double-beta decay processes can provide essential details on the interactions of neutrinos, and many experiments are underway that may be able to detect the highly sought neutrinoless double-beta decay channel. This decay can provide a measurement of the absolute mass scale of neutrinos, but only if the Nuclear Matrix Elements (NME) of the candidate nuclei are known to high precision. Predictions for the NMEs of one of the most heavily studied candidates,^76Ge, vary by at least 50% and need to be further investigated. The University of Notre Dame Nuclear Structure Lab is in a unique position to probe the pairing structure of nucleons in ^76Ge via a two-proton transfer reaction. A time of flight measurement identifies neutrons from the ^76Ge(^3He,n) reaction using a large acceptance neutron detector. The cosmic ray background in our detector is large compared to the neutron signal, making it necessary to construct a plastic scintillator veto counter. At least an 80% rejection of background is necessary to cut the fractional error in half. A Geant simulation of the veto plastic is necessary in understanding the expected vetoed background signal in our detector and optimizing the rejection system. This project will report on the energy spectrum our Geant simulation predicts from the scintillator, as well as the accuracy of our model compared to the actual energy spectrum taken from our scintillator. The data's relevance to the veto system and error analysis will be discussed.

Russell, Matthew

2009-10-01

249

Unparticle physics on cosmic ray photon and e±  

NASA Astrophysics Data System (ADS)

We study the effects of unparticle physics on the cosmic ray photon and e±, including on the pair production (PP) and elastic scattering (ES) of cosmic ray photon off various background radiations, and on the inverse Compton scattering of cosmic ray e± with cosmic radiations. We compute the spin-averaged amplitudes squared of three processes and find that the advent of unparticle will never significantly change the interactions of cosmic ray photon and e± with various background radiations, although the available papers show that ES which occurs in the tree-level through unparticle exchanges will easily surpass PP in the approximate parameter regions.

Chen, Shao-Xia; Hu, Rong

2009-10-01

250

Solar-planetary relationships: Cosmic rays 1979-1982  

NASA Astrophysics Data System (ADS)

The reviews of cosmic ray studies (1979-1982) cover a broad area reflecting the present scope of this discipline. Cosmic ray physics transcended the narrow restricted specialties of composition, flux, and modulation long ago. In fact, the cosmic ray energy regime appears to be anything above “thermal” (a remark attributed to Professor Bruno Rossi). At the present time, the relationship of cosmic ray studies to solar-terrestrial physics encompasses an extremely wide range of interrelated and associated astrophysical phenomena from the sun to the interplanetary medium and throughout the domain of the heliosphere. Because solar-terrestrial and astrophysical processes impress their signature on the cosmic ray flux, it is quite natural to look for these effects in the cosmic radiation data. For this reason, the reviews associated with cosmic rays cover solar activity, shocks and associated structure in the interplanetary medium, composition and modulation, and long-term effects.

Shea, M. A.

251

TRACING THE SOURCES OF COSMIC RAYS WITH MOLECULAR IONS  

SciTech Connect

The rate of ionization by cosmic rays (CRs) in interstellar gas directly associated with {gamma}-ray-emitting supernova remnants (SNRs) is for the first time calculated to be several orders of magnitude larger than the Galactic average. Analysis of ionization-induced chemistry yields the first quantitative prediction of the astrophysical H{sup +} {sub 2} emission line spectrum, which should be detectable together with H{sup +} {sub 3} lines. The predicted coincident observation of those emission lines and {gamma}-rays will help prove that SNRs are sources of CRs.

Becker, Julia K.; Schuppan, Florian [Ruhr-Universitaet Bochum, Fakultaet fuer Physik and Astronomie, Theoretische Physik IV, D-44780 Bochum (Germany); Black, John H.; Mohammadtaher Safarzadeh, E-mail: julia@tp4.rub.de [Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, SE-439 92 Onsala (Sweden)

2011-10-01

252

Cosmic ray acceleration in supernova blast waves  

NASA Astrophysics Data System (ADS)

Cosmic ray spectra produced over the lifetime of an evolving SNR blast wave are determined by solving the test particle approximation of diffusive shock acceleration in plane, steady shocks with homogeneous upstream and downstream media. The injection of 500-eV particles at the shock produces power laws up to at least 3 trillion eV. These power law spectra are at least as hard as the source spectra used in Leaky Box propagation calculations, as has been independently found by Bogdan and Voelk (1983). The correspondence of the present model to the reacceleration model of Blandford and Ostriker (1980) is shown, and it is demonstrated that the cooling effect in these models' expanding remnants may be sufficient to explain the overabundance of cosmic ray antiprotons in the 0.1-10 GeV kinetic energy range.

Moraal, H.; Axford, W. I.

1983-09-01

253

Measuring TeV Cosmic-Ray Electrons with CREST  

NASA Astrophysics Data System (ADS)

There is strong indirect evidence for the supernova shock acceleration of galactic cosmic-ray electrons through observations of non-thermal X-rays and TeV gamma rays from supernova remnants (SNRs). Current and past electron detectors, typically flown by high altitude balloons, have been limited in their ability to study high energy electrons in the local cosmic-ray flux by their short exposure times and small apertures. To date, no measurements have been made at energies greater than 2 TeV. Yet the detection of high-energy electrons would be extremely significant, yielding information about the spatial distribution of nearby cosmic ray sources. High-energy electrons lose energy rapidly during propagation in the Galaxy through synchrotron and inverse Compton processes and thus TeV electrons reaching the solar system have to originate at distances < 1 kpc, leaving few known supernova remnants from which these particles could originate. The spectral shape of high-energy electrons should, therefore, be strongly affected by the number of nearby sources, and their distance distribution. Conversely, if no such features in the high-energy electron spectrum are observed it will call into question our understanding of cosmic ray sources and propagation. The balloon-borne Cosmic Ray Electron Synchrotron Telescope (CREST) will detect high-energy electrons by measuring the X-ray synchrotron photons generated by these electrons in the Earth's magnetic field. This technique results in a substantial increase in the acceptance and sensitivity of the apparatus compared to the traditional direct detection of electrons. The instrument will consist of a 2m x 2m array of BGO crystals. Simulation studies indicate that with an ultra-long duration (100 day) flight, as many as 250 such electrons will be detected with energies greater than 2 TeV, with an expected background of only 1 event. A prototype instrument is currently being developed and will be flown in 2005 on a conventional balloon. The full CREST instrument will be flown in 2007 in Antarctica. This work is supported by a grant from the National Aeronautics and Space Administration.

Schubnell, M.; Bower, C.; Coutu, S.; DuVernois, M.; McKee, S.; Muller, D.; Musser, J.; Nutter, S.; Swordy, S.; Tarle, G.; Tomasch, A.; Yagi, A.

2004-08-01

254

Cosmic ?-ray bursts: Observations and modeling  

Microsoft Academic Search

It is now commonly accepted that cosmic ?-ray bursts (GRBs) are of cosmological origin. This conclusion is based on the statistical\\u000a analysis of GRBs and the measurements of line redshifts in GRB optical afterglows, i.e., in the so-called long GRBs. In this\\u000a review, the models of radiation and models of GRB sources are considered. In most of these models, if

G. S. Bisnovatyi-Kogan

2006-01-01

255

The Cosmic Gamma-Ray Bursts  

Microsoft Academic Search

Cosmic gamma-ray bursts are one of the great frontiers of astrophysics today.\\u000aThey are a playground of relativists and observers alike. They may teach us\\u000aabout the death of stars and the birth of black holes, the physics in extreme\\u000aconditions, and help us probe star formation in the distant and obscured\\u000auniverse. In this review we summarise some of

S. G. Djorgovski; D. A. Frail; S. R. Kulkarni; R. Sari; J. S. Bloom; T. J. Galama; F. A. Harrison; P. A. Price; D. Fox; D. E. REICHART; S. Yost; E. Berger; A. Diercks; R. Goodrich; F. Chaffee

2001-01-01

256

Joint acceleration mechanisms for solar cosmic rays  

NASA Astrophysics Data System (ADS)

Using Monte Carlo method we have simulated solar cosmic ray spectra (3He, 4He, O and Fe) at the flare site and at the Earth. It is shown that besides stochastic acceleration by Alfvenic turbulence an impulsive electric field of the current sheet significantly affects the ion energy spectra at low energies. Both mechanisms could explain some peculiarities in the energy spectra of heavy ions observed in experiments onboard ACE.

Lytova, M. F.; Ostryakov, V. M.

2013-02-01

257

Cosmic ray gradients in the outer heliosphere  

NASA Astrophysics Data System (ADS)

Launched in 1972 and 1973 respectively, the Pioneer 10 and 11 spacecraft are now probing the outer heliosphere on their final escape from the sun. The data in this paper extend for almost an entire solar cycle from launch to early 1983, when Pioneer 10 was at a heliocentric distance of 29 AU and Pioneer 11, 13 AU. The UCSD instruments on board were used to study the gradient, and to look at the time and spatial variations of the cosmic ray intensities.

Walker, F.; Wake, B.; Ip, W.-H.; Axford, I.

1983-08-01

258

Density of Cosmic-Ray Neutrons in the Atmosphere  

Microsoft Academic Search

A new method of measuring cosmic-ray neutrons has been developed, yielding a precision (___2 per cent) heretofore unattainable in balloon instrumentation. Ionization chambers using a quartz fiber electrometer of the Neher design and filled with BøFs detected the neutrons by means of the BXø(n, a)Li 7 reaction. Ionization chambers filled with BxxFs or argon measured the background current due to

Ralph F. Miles

1964-01-01

259

Acceleration and propagation of ultrahigh energy cosmic rays  

NASA Astrophysics Data System (ADS)

The origin of the highest energy cosmic rays represents one of the most conspicuous enigmas of modern astrophysics, in spite of gigantic experimental efforts in the past fifty years, and of active theoretical research. The past decade has known exciting experimental results, most particularly the detection of a cut-off at the expected position for the long sought Greisen-Zatsepin-Kuzmin suppression as well as evidence for large scale anisotropies. This paper summarizes and discusses recent achievements in this field.

Lemoine, Martin

2013-02-01

260

Ultra High Energy Cosmic Rays: Spectral Signatures and Observations  

NASA Astrophysics Data System (ADS)

We review the observations of Ultra High Energy Cosmic Rays (UHECR), focusing on the energy spectra as measured by HiRes, Telescope Array (TA) and Auger detectors. We found that highest energy Auger steepening does not agree with GZK cutoff, which is most probably explained by the nuclei mass composition detected by Auger. At present the difference in mass composition in Auger and HiRes/TA data remains the main unsolved problem of UHECR origin.

Grigorieva, S.

2013-02-01

261

Erich Regener - a forgotten cosmic ray pioneer  

NASA Astrophysics Data System (ADS)

In the 1930s the German physicist Erich Regener (1881-1955), did important work on the measurement of the rate production of ionisation in the atmosphere and deep under-water. He discovered, along with one of his students, Georg Pfotzer, the altitude at which the production of ionisation in the atmosphere reaches a maximum, often and misleadingly called the Pfotzer maximum. He was one of the first to estimate the energy density of cosmic rays, an estimate used by Baade and Zwicky to postulate that supernovae might be the source of cosmic rays. Yet Regener's name is little known largely because he was forced to take early retirement by the National Socialists in 1937 as his wife had Jewish ancestors. In this paper we review his work on cosmic rays and the subsequent influence that he had on the subject through his son, his son-in-law, his grandson and his students. He was nominated for the Nobel Prize in Physics by Schroedinger in 1938. He died in 1955 at the age of 73.

Carlson, Per; Watson, Alan

2013-04-01

262

Electrons and Positrons in Cosmic Rays  

NASA Astrophysics Data System (ADS)

This review concentrates on the results obtained, over the last ten years, on the astrophysics of high-energy cosmic ray electrons and positrons. The anomalies, observed in the data of recent experiments (possible bump in the electron spectrum and the PAMELA anomaly in the positron fraction) are discussed through the systematic use of simple analytical solutions of the transport equations for cosmic ray electrons. Three main ways of explaining the origin of the anomalies are considered: the conservative way supposing the positrons to be pure secondary particles; the nearby sources like pulsars origin; and the dark matter origin. This review discusses, also, the inability to select the pulsars model or the dark matter model to explain the electron anomalies on the basis of the electron spectra with the usual large energy binning ( 15%). It is argued that the signature of nearby pulsars origin of the anomalies against the dark matter origin could be the fine structure of the cosmic ray electron spectrum predicted in the Malyshev et al. paper (2009) and which was observed in the data from the high-resolution ATIC experiment (2009-2011). To date, the high-resolution ATIC data was the only experimental result of this type published in the literature. Therefore, they should be tested by other experiments as soon as possible. Generally, there is, also, rather controversial situations between the data of the majority of recent experiments and, consequently, there is a noted urgent need for new high-precision and high-statistical experiments.

Panov, A. D.

2013-02-01

263

Observing cosmic nuclei in gamma rays  

NASA Astrophysics Data System (ADS)

Nucleosynthesis events in cosmic objects create new nuclei, admixtures of radioactive isotopes being part of the matter ejected into interstellar space by these events. Gamma rays are emitted in radioactive decays, and can be measured with space-based gamma-ray telescopes. Four mission years of INTEGRAL have led to discoveries of new sources and to detailed astronomical refinements of already-known gamma-ray line emission. As part of the main science objectives of INTEGRAL's spectrometer SPI, diffuse emission from annihilation of positrons has presented a new puzzle, as the Galactic distribution of their presumed sources does not agree with the gamma-ray image. Recent massive-star nucleosynthesis is traced throughout the Galaxy with radioactivites seen in 26Al and now also 60Fe gamma rays; precision line spectroscopy now reveals Doppler shifts for the 26Al line, separately for different parts of the Galaxy. This provides new insights into the dynamics of hot interstellar gas. The processes generating new atomic nuclei in stars and supernovae are reflected in the abundances of the ejected radioactivities. For individual supernovae, measurements of 44Ti with its 85 year decay time probes the symmetry of the supernova interior. Since such gamma-ray measurements probe the generation of new nuclei in cosmic sites through a radiation process which is independent of environmental parameters such as temperature or ionization, it will remain worthwhile to further develop instrumentation in this window to the nuclear-physics universe.

Diehl, Roland

2008-01-01

264

The intergalactic propagation of ultrahigh energy cosmic ray nuclei  

SciTech Connect

We investigate the propagation of ultra-high energy cosmic ray nuclei (A = 1-56) from cosmologically distant sources through the cosmic radiation backgrounds. Various models for the injected composition and spectrum and of the cosmic infrared background are studied using updated photodisintegration cross-sections. The observational data on the spectrum and the composition of ultra-high energy cosmic rays are jointly consistent with a model where all of the injected primary cosmic rays are iron nuclei (or a mixture of heavy and light nuclei).

Hooper, Dan; /Fermilab; Sarkar, Subir; /Oxford U., Theor. Phys.; Taylor, Andrew M.; /Oxford U.

2006-08-01

265

TeV Gamma Rays and Cosmic-Ray Acceleration in Supernova Remnants  

NASA Astrophysics Data System (ADS)

If supernova remnants (SNRs) are the site of cosmic-ray acceleration, the associated nuclear interactions should result in an observable flux of ?^0-decay ?-rays for the nearest SNRs. Measurements of the TeV ?-ray flux from nearby, radio-bright SNRs have been made with the Whipple imaging air Cherenkov telescope but reveal no significant emission (Buckley et al. 1998). Three of these SNRs (IC443, ?-Cygni and W44) are spatially coincident with low-latitude unidentified sources detected with the Energetic Gamma-Ray Experiment Telescope (EGRET). If the EGRET ?-ray fluxes result from cosmic-ray interactions, then the EGRET and Whipple data are found to be collectively inconsistent with a cosmic-ray source spectrum flatter than ~ E-2.4. The Whipple upper limits for IC443 and ?-Cygni are also inconsistent with a priori predictions if these remnants are indeed expanding into regions where the average density of the interstellar medium is enhanced by the presence of molecular clouds. Recent observations of nonthermal X-rays in the limbs of a number of shell-type SNRs (including IC443, SN 1006 and Cassiopeia A) signify the presence of very high energy electrons (E>10 TeV) in the vicinity of SNR shells. More Recently, the CANGAROO atmospheric Cherenkov telescope has detected significant TeV emission from the remnant SN 1006 (Tanimori et al. 1998), but in this case the TeV emission most probably arises from inverse-Compton scattering by energetic electrons. Despite the growing body of evidence for shock acceleration of electrons in SNRs, there is still no direct evidence pointing to the source of cosmic ray nuclei and the data are beginning to require a modification of the simplest models of shock acceleration and energy dependent propagation of cosmic rays.

Buckley, James H.

1998-04-01

266

The Dynamical Role of Cosmic Rays in Galactic Winds  

NASA Astrophysics Data System (ADS)

Cosmic rays are well-known for generating synchrotron radiation, as well as for helping to ionize cool gas in the interstellar medium. In this paper, we review the dynamical role of cosmic rays, focusing in particular on the Streaming Instability and how cosmic-ray pressure can help to launch galactic winds. We review progress in modeling soft X-ray emission and synchrotron emission, observed towards the center of the Milky Way, as a wind driven by both cosmic-ray and thermal-gas pressure. We also outline our ongoing work to include driving by magnetic pressure and galactic rotation, in a general semi-analytic numerical framework.

Everett, J.; Zweibel, E.; Hu, K.

2010-12-01

267

Cosmic-Ray Neon, Wolf-Rayet Stars, and the Superbubble Origin of Galactic Cosmic Rays  

NASA Astrophysics Data System (ADS)

We report the abundances of neon isotopes in the Galactic cosmic rays (GCRs) using data from the Cosmic Ray Isotope Spectrometer (CRIS) aboard the Advanced Composition Explorer (ACE). These abundances have been measured for seven energy intervals over the energy range of 84<=E/M<=273 MeV nucleon-1. We have derived the 22Ne/20Ne ratio at the cosmic-ray source using the measured 21Ne, 19F, and 17O abundances as ``tracers'' of secondary production of the neon isotopes. Using this approach, the 22Ne/20Ne abundance ratio that we obtain for the cosmic-ray source is 0.387+/-0.007(statistical)+/-0.022(systematic). This corresponds to an enhancement by a factor of 5.3+/-0.3 over the 22Ne/20Ne ratio in the solar wind. This cosmic-ray source 22Ne/20Ne ratio is also significantly larger than that found in anomalous cosmic rays, solar energetic particles, most meteoritic samples of matter, and interplanetary dust particles. We compare our ACE CRIS data for neon and refractory isotope ratios, and data from other experiments, with recent results from two-component Wolf-Rayet (W-R) models. The three largest deviations of GCR isotope ratios from solar system ratios predicted by these models, 12C/16O, 22Ne/20Ne, and 58Fe/56Fe, are indeed present in the GCRs. In fact, all of the isotope ratios that we have measured are consistent with a GCR source consisting of about 80% material with solar system composition and about 20% W-R material. Since W-R stars are evolutionary products of OB stars, and most OB stars exist in OB associations that form superbubbles, the good agreement of these data with W-R models suggests that superbubbles are the likely source of at least a substantial fraction of GCRs.

Binns, W. R.; Wiedenbeck, M. E.; Arnould, M.; Cummings, A. C.; George, J. S.; Goriely, S.; Israel, M. H.; Leske, R. A.; Mewaldt, R. A.; Meynet, G.; Scott, L. M.; Stone, E. C.; von Rosenvinge, T. T.

2005-11-01

268

Supernova Remnant Kes 17: An Efficient Cosmic Ray Accelerator inside a Molecular Cloud  

NASA Astrophysics Data System (ADS)

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.; Castro, Daniel; Slane, Patrick O.; Temim, Tea; Hughes, John P.; Rakowski, Cara

2013-11-01

269

On the transition from Galactic to extragalactic cosmic rays  

NASA Astrophysics Data System (ADS)

The Earth is permanently exposed to a flux of high-energy ionized nuclei - the cosmic rays. Most of these particles are accelerated in our Galaxy, most probably in supernova remnants. Cosmic rays are magnetically bound to our Galaxy up to energies of about 10^17 to 10^18 eV. At higher energies the observed particles most likely originate in other galaxies and are usually referred to as extra-galactic cosmic rays. Thus, the energy region between 10^17 and 10^18 eV is of great astrophysical interest. From a detailed measurement of the composition of cosmic rays in this energy regime we expect deeper insight into both, the origin of Galactic and extra-galactic cosmic rays. The status of the actual research will be reviewed and implications on our understanding of the origin of cosmic rays will be discussed.

Hoerandel, Joerg

2012-03-01

270

Stability of a cosmic ray modified tangential discontinuity  

NASA Astrophysics Data System (ADS)

We consider the dispersion relation for waves in a cosmic ray modified plasma for the case when the background flow consists of a cosmic ray pressure balance structure, in which pg+pc=const. where pc and pg denote the cosmic ray and thermal gas pressures respectively. The stability analysis shows that waves at an arbitrary point in the flow may be driven unstable if the cosmic ray pressure gradient is sufficiently large to overcome wave damping due to cosmic ray diffusion. Following S. Chalov's work (1) we analyze the instability of a cosmic ray modified tangential discontinuity. Chalov considered the case where pc=const. throughout the structure, whereas in our analysis both pc and pg vary in the direction perpendicular to the surface separating two flow regions. Predictions of the linear theory are compared to numerical simulations. Applications to the stability of the heliopause are discussed.

Zakharian, A. R.; Webb, G. M.; Zank, G. P.

1999-06-01

271

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

SciTech Connect

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)

2007-06-19

272

Cosmic Ray induced Neutron and Gamma-Ray bursts in a Lead Pile  

SciTech Connect

The neutron background is created primarily by cosmic rays interactions. Of particular interest for SNM detection is an understanding of burst events that resemble fission chains. We have been studying the interaction of cosmic rays with a lead pile that is efficient at creating neutron bursts from cosmic ray interactions. The neutron burst size depends on the configuration of the lead. We have found that the largest bursts appear to have been created by primaries of energy over 100 GeV that have had a diffractive interaction with the atmosphere. The large events trigger muon coincidence paddles with very high efficiency, and the resulting interactions with the lead pile can create over 10, 000 neutrons in a burst.

Chapline, G; Hagmann, C; Kerr, P; Snyderman, N J; Wurtz, R

2007-05-08

273

Ultra-High Energy Cosmic Rays and Cosmogenic Neutrinos  

NASA Astrophysics Data System (ADS)

Although the sources and composition of ultra-high energies cosmic rays is unknown, in most scenarios a significant flux of very high energy neutrinos should be present throughout the universe. We show that even if ultra-high energy cosmic rays are composed of heavy nuclei from extragalactic sources, their propagation over cosmological distances generate a neutrino flux comparable to that of proton primaries depending on the maximum energy and cosmological evolution of the source. The resulting neutrino flux has a new peak at ˜ 1014 eV generated by neutron decay and reproduces the double peak structure due to photopion production at higher energies (˜ 1018 eV). The generated neutrino flux may be detected by future experiments.

Ave, M.; Busca, N.; Olinto, A. V.; Watson, A. A.; Yamamoto, T.

2004-11-01

274

Gamma-ray bursts, cosmic-rays and neutrinos  

Microsoft Academic Search

The ?-ray burst (GRB) model for production of ultra-high energy, > 1019 eV, cosmic-rays is based on the hypothesis that GRBs arise from the dissipation of the kinetic energy of relativistic fireballs at cosmological distances. Recent observations of delayed low energy emission, “afterglow,” from GRB sources strongly support the validity of this hypothesis. Observations also provide quantitative support for the

Eli Waxman

2000-01-01

275

Theory and Modeling of Galactic Cosmic Rays: Trends and Prospects  

NASA Astrophysics Data System (ADS)

We address past and future trends in the theory and modeling of galactic cosmic rays in the heliosphere, and select some of the outstanding issues where future progress is anticipated. We discuss the theory of diffusive transport, briefly discuss drifts, the force-field approximation, and current numerical methods. Special attention is given to the areas of modeling cosmic rays in the heliosheath, the implications of the recent unusual solar minimum, and the understanding of high rigidity cosmic-ray anisotropies.

Kóta, József

2013-06-01

276

Cosmic-Ray Modulation in the Heliosphere A Phenomenological Study  

Microsoft Academic Search

The heliospheric cosmic-ray network–Pioneer 10\\/11, Voyager 1\\/2, Ulysses and IMP 8 have provided detailed observations of galactic and anomalous cosmic rays over a period of time that now exceeds 25 years and extends to heliocentric distances beyond 65 AU. These data, when compared over consecutive 11 year solar cycles, clearly establishes the existence of a 22-year cosmic ray modulation cycle

Frank B. McDonald

1998-01-01

277

Evaluation of Cosmic Ray Rejection Algorithms on Single-Shot Exposures  

NASA Astrophysics Data System (ADS)

To maximise data output from single-shot astronomical images, the rejection of cosmic rays is important. We present the results of a benchmark trial comparing various cosmic ray rejection algorithms. The procedures assess relative performances and characteristics of the processes in cosmic ray detection, rates of false detections of true objects, and the quality of image cleaning and reconstruction. The cosmic ray rejection algorithms developed by Rhoads (2000, PASP, 112, 703), van Dokkum (2001, PASP, 113, 1420), Pych (2004, PASP, 116, 148), and the IRAF task XZAP by Dickinson are tested using both simulated and real data. It is found that detection efficiency is independent of the density of cosmic rays in an image, being more strongly affected by the density of real objects in the field. As expected, spurious detections and alterations to real data in the cleaning process are also significantly increased by high object densities. We find the Rhoads' linear filtering method to produce the best performance in the detection of cosmic ray events; however, the popular van Dokkum algorithm exhibits the highest overall performance in terms of detection and cleaning.

Farage, Catherine L.; Pimbblet, Kevin A.

2005-08-01

278

SurveillanceRadiographic imaging with cosmic-ray muons  

NASA Astrophysics Data System (ADS)

Despite its enormous success, X-ray radiography has its limitations: an inability to penetrate dense objects, the need for multiple projections to resolve three-dimensional structure, and health risks from radiation. Here we show that natural background muons, which are generated by cosmic rays and are highly penetrating, can be used for radiographic imaging of medium-to-large, dense objects, without these limitations and with a reasonably short exposure time. This inexpensive and harmless technique may offer a useful alternative for detecting dense materials - for example, a block of uranium concealed inside a truck full of sheep.

Borozdin, Konstantin N.; Hogan, Gary E.; Morris, Christopher; Priedhorsky, William C.; Saunders, Alexander; Schultz, Larry J.; Teasdale, Margaret E.

2003-03-01

279

Lithium, beryllium, and boron in cosmology and cosmic rays.  

NASA Astrophysics Data System (ADS)

Observations of metal-deficient halo stars indicate the presence of 6Li, Be, and B in the early Galaxy. It is shown that there is neither convincing observational evidence nor theoretical motivation that these elements are primordial. Evidence is presented which suggests that they were produced by cosmic ray interactions in the early interstellar medium. If the 6Li, Be and B are indeed of cosmic ray origin, then the same cosmic ray interactions also produce 7Li. One can deduce this (small) cosmic ray component to Li subtract this from the observed abundance to obtain the true, primordial Li abundance.

Fields, B. D.

280

A cosmic-ray-mediated shock in the solar system  

NASA Astrophysics Data System (ADS)

It is pointed out that the flare-induced blast wave of Aug. 4, 1972, the most violent disturbance in the solar wind on record, produced cosmic rays with an efficiency of about 50%. Such a high efficiency is predicted by the self-regulating production model of cosmic-ray origin in shocks. Most interplanetary shocks, according to simple theoretical analysis, are not strong enough to produce cosmic rays efficiently. However, if shock strength is the key parameter governing efficiency, as present interplanetary data suggest, then shocks from supernova blasts, quasar outbursts, and other violent astrophysical phenomena should be extremely efficient sources of cosmic rays.

Eichler, D.

1981-08-01

281

GeV ?-rays and the origin of cosmic rays  

NASA Astrophysics Data System (ADS)

The past decade has brought significant advances in our understanding of acceleration processes at work in shell-type as well as in plerionic Supernova remnants through observations from X-rays to VHE Gamma-rays. Unprecedented morphological studies of gamma-ray emission from shell-type Supernova remnants show a striking correlation to X ray emission. Gamma-ray energy spectra of up to 100~TeV confirm particle acceleration close to the "knee" in the Cosmic ray spectrum at 1~PeV in these objects. The Fermi-LAT is contributing to our understanding of these objects through observations in range between 20 MeV and 300 GeV. All these observations allow for the first time to severely constrain gamma-ray emission models and allow for studies of the parent population accelerated in these objects. I will review the current observational status of gamma-ray emission and our understanding of the origin of cosmic rays.

Funk, Stefan

2013-02-01

282

Cosmic Rays in Galactic and Extragalactic Magnetic Fields  

NASA Astrophysics Data System (ADS)

We briefly review sources of cosmic rays, their composition and spectra as well as their propagation in the galactic and extragalactic magnetic fields, both regular and fluctuating. A special attention is paid to the recent results of the X-ray and gamma-ray observations that shed light on the origin of the galactic cosmic rays and the challenging results of Pierre Auger Observatory on the ultra high energy cosmic rays. The perspectives of both high energy astrophysics and cosmic-ray astronomy to identify the sources of ultra high energy cosmic rays, the mechanisms of particle acceleration, to measure the intergalactic radiation fields and to reveal the structure of magnetic fields of very different scales are outlined.

Aharonian, Felix; Bykov, Andrei; Parizot, Etienne; Ptuskin, Vladimir; Watson, Alan

2012-05-01

283

Composition and energy spectra of cosmic rays--Implications for cosmic ray origins  

SciTech Connect

A brief review is presented of the energy spectrum and composition of the cosmic rays up to the knee region near 10{sup 15} eV. The measurements suggest a picture based on acceleration in supernova shocks, including shocks produced by interaction with the winds of massive pre-supernova stars, coupled with a leaky box model of propagation through the galaxy.

Cherry, Michael L. [Dept. of Physics and Astronomy, Louisiana State Univ., Baton Rouge, Los Angeles 70803 (United States)

1997-05-20

284

EDITORIAL: Focus on High Energy Cosmic Rays FOCUS ON HIGH ENERGY COSMIC RAYS  

Microsoft Academic Search

The topic of high-energy cosmic rays has recently attracted significant attention. While the AGASA and HiRes Observatories have closed after many years of successful operation, the Pierre Auger Observatory began taking data in January 2004 and the first results have been reported. Plans for the next generation of instruments are in hand: funding is now being sought for the northern

Masahiro Teshima; Alan A. Watson

2009-01-01

285

The galactic origin of cosmic rays. I  

NASA Astrophysics Data System (ADS)

The theoretical basis for the supernova envelope shock origin of cosmic rays is reviewed. The theoretical explanation of the SN Type I light curve requires the ejection of a relativistic mass fraction. The criterion of the adiabatic deceleration by Alfven wave trapping neither applies in theory, when beta is greater than 1, or practice, as in the Starfish high-altitude nuclear explosion experiment. Arguments of delayed acceleration due to K-capture are not applicable to SN ejecta because a period of prompt recombination exists before subsequent stripping in propagation.

Colgate, S. A.

286

Modulation of Cosmic Rays in the Heliosheath  

NASA Astrophysics Data System (ADS)

We present numerical simulations modeling the transport of galactic cosmic rays in the heliosphere including the termination shock (TS) and the heliosheath beyond the TS. The present work is a first stage aiming toward a 3-dimensional treatment. It is our purpose to develop a simple fast stochastic integration method that can handle discontinuities like the TS. Here, we consider a simple spherical model including diffusion, convection, adiabatic cooling and shock accleration at the TS. An incompressible heliosheath is assumed beyond the TS. We briefly address the underlying physics, present illustrative simulation results, and discuss their implications.

Kóta, J.

2011-10-01

287

Green River Community College Cosmic Ray Detector  

NASA Astrophysics Data System (ADS)

The Washington Area Large scale Time coincidence Array (WALTA) researches high-energy cosmic ray and has placed particle detector arrays around the Seattle area to increase the accuracy of muon information. Green River Community College is one of the schools in collaboration with WALTA and offers its students under-graduate research by working with the particle detector arrays, data collecting and reporting. The student's work ranges from polishing scintillators and planning the physical setup of detector components to solving data acquisition problems.

Roma, Andrea; Harrington, Crissy; Isic, Mirela; Adams, Andrew; Draper, Ron

2008-05-01

288

Galactic origin of cosmic rays I  

SciTech Connect

The theoretical basis for the supernova envelope shock origin of cosmic rays is reviewed. The theoretical explanation of the SN Type I light curve requires the ejection of a relativistic mass fraction. The criterion of the adiabatic decelleration by Alfven wave trapping neither applies in theory, when ..beta.. > 1, or practice, the Starfish high altitude nuclear explosion experiment. Arguments of delayed acceleration due to K-capture are not applicable to SN ejecta because a period of prompt recombination exists before subsequent stripping in propagation.

Colgate, S.A.

1981-01-01

289

Unusual anisotropic wave trains in cosmic rays  

NASA Astrophysics Data System (ADS)

Several workers have attempted to find out the possible origin of the "high amplitude wave trains" of enhanced diurnal variation of cosmic rays and to develop a suitable realistic theoretical model that can explain the different harmonics in individual days. The various observed harmonics of the cosmic-ray variation may be understood on a unified basis if the free-space cosmic-ray anisotropy is non-sinusoidal in form. The major objective of this paper is to study the first three harmonics of high-amplitude wave trains of cosmic-ray intensity over the period 1981-1994 for Deep River neutron monitoring station. The main characteristic of these events is that the high-amplitude wave trains show a maximum intensity of diurnal component in a direction earlier than 18:00 h/co-rotational direction. It is noteworthy that the amplitude significantly enhanced and the phase remains in the co-rotational direction during the years close to solar-activity maximum for first harmonic. Significant deviations have been observed in the semi-diurnal amplitude after the onset of solar-activity maximum. This leads us to conclude that the amplitude as well as direction of the first harmonic and the amplitude of second harmonic are correlated with solar-activity cycle during these HAEs. The amplitude and phase of all the three harmonics (diurnal/semi-diurnal/tri-diurnal) are not found to depend on the polarity of Bz component of interplanetary magnetic field for long-term variation. The occurrence of high-amplitude events is dominant for the positive polarity of Bz component of IMF. The occurrence of HAEs is dominant during the period of average solar-wind velocity, but their occurrence during HSSWSs cannot be denied. The possibility of occurrence of these events is more during the periods of co-rotating streams. The occurrence of HAE is dominant when Dst-index remains negative and this point is not reported earlier in the litterature. All the high amplitude events occurred, when geomagnetic activity index, Ap, remains ?20.

Mishra, Rajesh K.; Mishra, Rekha Agarwal

2007-11-01

290

Turbulent heating in solar cosmic ray theory  

NASA Astrophysics Data System (ADS)

The heating of minor ions in solar flares by wave-wave-particle interaction with Langmuir waves, or ion acoustic waves, can be described by a diffusion equation in velocity-space for the particle distribution function. The dependence of the heating on the ion charge and mass, and on the composition of the plasma, is examined in detail. It is found that the heating mechanisms proposed by Ibragimov and Kocharov cannot account for the enhanced abundances of heavy elements in the solar cosmic rays.

Weatherall, J.

1983-07-01

291

The cosmic-ray experiment KASCADE  

NASA Astrophysics Data System (ADS)

KASCADE has been designed to measure air showers of primary cosmic-ray energies in the PeV region and to investigate the knee phenomenon in the all-particle energy spectrum. Several observations are measured simultaneously for each event by different detector systems. The experiment started to take data in 1996 and has been completed and extended since then. The individual detector systems and their performances are described. Also, the experience in long-term operation of the experiment and the interplay between different components is outlined.

Antoni, T.; Apel, W. D.; Badea, F.; Bekk, K.; Bercuci, A.; Blümer, H.; Bozdog, H.; Brancus, I. M.; Büttner, C.; Chilingarian, A.; Daumiller, K.; Doll, P.; Engler, J.; Feßler, F.; Gils, H. J.; Glasstetter, R.; Haeusler, R.; Haungs, A.; Heck, D.; Hörandel, J. R.; Iwan, A.; Kampert, K.-H.; Klages, H. O.; Maier, G.; Mathes, H. J.; Mayer, H. J.; Milke, J.; Müller, M.; Obenland, R.; Oehlschläger, J.; Ostapchenko, S.; Petcu, M.; Rebel, H.; Risse, M.; Roth, M.; Schatz, G.; Schieler, H.; Scholz, J.; Thouw, T.; Ulrich, H.; Vardanyan, A.; Weber, J.; Weindl, A.; Wentz, J.; Wochele, J.; Zabierowski, J.; Zagromski, S.

2003-11-01

292

CRAnE: A JAS-based Data Acquisition System for Cosmic Rays  

SciTech Connect

Cosmic Ray Analysis Environment (CRAnE) is a software tool designed to collect and plot data from a cosmic ray telescope (CRT) connected to a computer serial port. As a plug-in to Java Analysis Studio (JAS), CRAnE provides visual displays of incoming cosmic ray rates as they are detected. In an effort to make the program user-friendly, it operates through a graphical user interface. This paper describes the features of CRAnE and includes installation and operation instructions in the appended user's manual.

Langeveld, Willy G.J.

2003-08-25

293

The first cosmic ray albedo proton map of the Moon  

NASA Astrophysics Data System (ADS)

Neutrons emitted from the Moon are produced by the impact of galactic cosmic rays (GCRs) within the regolith. GCRs are high-energy particles capable of smashing atomic nuclei in the lunar regolith and producing a shower of energetic protons, neutrons and other subatomic particles. Secondary particles that are ejected out of the regolith become “albedo” particles. The neutron albedo has been used to study the hydrogen content of the lunar regolith, which motivates our study of albedo protons. In principle, the albedo protons should vary as a function of the input GCR source and possibly as a result of surface composition and properties. During the LRO mission, the total detection rate of albedo protons between 60 MeV and 150 MeV has been declining since 2009 in parallel with the decline in the galactic cosmic ray flux, which validates the concept of an albedo proton source. On the other hand, the average yield of albedo protons has been increasing as the galactic cosmic ray spectrum has been hardening, consistent with a disproportionately stronger modulation of lower energy GCRs as solar activity increases. We construct the first map of the normalized albedo proton emission rate from the lunar surface to look for any albedo variation that correlates with surface features. The map is consistent with a spatially uniform albedo proton yield to within statistical uncertainties.

Wilson, Jody K.; Spence, Harlan E.; Kasper, Justin; Golightly, Michael; Bern Blake, J.; Mazur, Joe E.; Townsend, Lawrence W.; Case, Anthony W.; Dixon Looper, Mark; Zeitlin, Cary; Schwadron, Nathan A.

2012-06-01

294

FAMOUS - A prototype silicon photomultiplier telescope for the fluorescence detection of ultra-high-energy cosmic rays  

NASA Astrophysics Data System (ADS)

Due to their high photon detection efficiency, silicon photomultipliers (SiPMs) promise to increase the sensitivity of today's fluorescence telescopes which use photomultiplier tubes to detect light originating from extensive air showers. On the other hand, drawbacks like a small sensitive area, a strong temperature dependence, a high noise rate and a reduced dynamic range have to be managed. We present plans for FAMOUS, a prototype fluorescence telescope using SiPMs and a special light collecting optical system of Winston cones to increase the sensitive area. The prototype will make use of a Fresnel lens. For several different types of SiPMs we measured their characteristics. Moreover, we will present the R&D in compact modular electronics using photon counting techniques. An evaluation of the performance of the optical telescope design is performed by means of a full detector simulation.

Stephan, Maurice; Assis, Pedro; Brogueira, Pedro; Ferreira, Miguel; Hebbeker, Thomas; Lauscher, Markus; Mendes, Luís; Meurer, Christine; Middendorf, Lukas; Pimenta, Mário; Schumacher, Johannes

2013-06-01

295

A cosmic ray-climate link and cloud observations  

NASA Astrophysics Data System (ADS)

Despite over 35 years of constant satellite-based measurements of cloud, reliable evidence of a long-hypothesized link between changes in solar activity and Earth's cloud cover remains elusive. This work examines evidence of a cosmic ray cloud link from a range of sources, including satellite-based cloud measurements and long-term ground-based climatological measurements. The satellite-based studies can be divided into two categories: (1) monthly to decadal timescale analysis and (2) daily timescale epoch-superpositional (composite) analysis. The latter analyses frequently focus on sudden high-magnitude reductions in the cosmic ray flux known as Forbush decrease events. At present, two long-term independent global satellite cloud datasets are available (ISCCP and MODIS). Although the differences between them are considerable, neither shows evidence of a solar-cloud link at either long or short timescales. Furthermore, reports of observed correlations between solar activity and cloud over the 1983-1995 period are attributed to the chance agreement between solar changes and artificially induced cloud trends. It is possible that the satellite cloud datasets and analysis methods may simply be too insensitive to detect a small solar signal. Evidence from ground-based studies suggests that some weak but statistically significant cosmic ray-cloud relationships may exist at regional scales, involving mechanisms related to the global electric circuit. However, a poor understanding of these mechanisms and their effects on cloud makes the net impacts of such links uncertain. Regardless of this, it is clear that there is no robust evidence of a widespread link between the cosmic ray flux and clouds.

Laken, Benjamin A.; Pallé, Enric; ?alogovi?, Jaša; Dunne, Eimear M.

2012-11-01

296

The isotopic composition of cosmic-ray beryllium and its implication for the cosmic ray's age  

NASA Astrophysics Data System (ADS)

We report a new measurement of the cosmic-ray isotopic composition of beryllium in the low-energy range from 35 to 113 MeV per nucleon. This measurement was made using the High Energy Telescope of the CRS experiment on the Voyager 1 and 2 spacecraft during the time period from 1977 to 1991. In this overall time period of 14 years the average solar modulation level was about 500 MV. The cosmic-ray beryllium isotopes were completely separated with an average mass resolution sigma of 0.185 amu. The isotope fractions of Be-7, Be-9, and Be-10 obtained are 52.4 +/- 2.9%, 43.3 +/- 3.7%, and 4.3 +/- 1.5%, respectively. The measured cosmic-ray abundances of Be-7 and Be-9 are found to be in agreement with calculations based on standard Leaky-Box model for the interstellar propagation of cosmic-ray nuclei using the recent cross sections of the New Mexico-Saclay collaboration. From our observed ratio Be-10/Be = 4.3 +/- 1.5% we deduce an average interstellar density of about 0.28 (+0.14, -0.11) atoms/cu cm, and a cosmic-ray lifetime for escape of 27 (+19, -9) x 106 years. The surviving fraction of Be-10 is found to be 0.19 +/- 0.07. Modifications to the conclusions of the Leaky-Box model when a diffusion + convection halo model for propagation is used are also considered.

Lukasiak, A.; Ferrando, P.; McDonald, F. B.; Webber, W. R.

1994-03-01

297

Cosmic rays in the Milky Way and other galaxies  

NASA Astrophysics Data System (ADS)

Cosmic rays fill up the entire volume of galaxies, providing an important source of heating and ionisation of the interstellar medium, and may play a significant role in the regulation of star formation and evolution of galaxies. Diffuse emissions from radio to high-energy gamma rays (> 100 MeV) arising from various interactions between cosmic rays and the interstellar medium, interstellar radiation field, and magnetic field, are currently the best way to trace the intensities and spectra of cosmic rays in the Milky Way and other galaxies. In this talk, I will give an overview of the observations of the cosmic-ray induced emissions from our own and other galaxies, in particular, results from the Fermi-LAT and Imaging Air Cerenkov telescopes. I will also talk about what can be deduced about the cosmic-ray origin and propagation from these observations.

Porter, Troy

2012-07-01

298

Implications of Cosmic Radiation on the Martian Surface for Microbial Survival and Detection of Fluorescent Biosignatures  

NASA Astrophysics Data System (ADS)

We report experimental results on the survival of microbial life exposed to cosmic rays on Mars, building on our computer modeling of this ionizing radiation. On-going work is on the irradiation degradation of detectable fluorescent biosignatures.

Dartnell, L. R.; Storrie-Lombardi, M. C.; Muller, J.-P.; Griffiths, A. D.; Coates, A. J.; Ward, J. M.

2011-03-01

299

REal-time COsmic Ray Database (RECORD)  

NASA Astrophysics Data System (ADS)

In this paper we present a first distributed REal-time COsmic Ray Database (RECORD). The aim of the project is to develop a unified database with data from different neutron monitors collected together, in unified format and to provide a user with several commonly used data access methods. The database contains not only original cosmic ray data but also auxiliary data necessary for scientific data analysis. Currently the database includes Lomn.Stit, Moscow, Oulu; Tixie Bay, Yakutsk stations. The main database server is located in IKFIA SB RAS (Yakutsk) but there will be several mirrors of the database. The database and all its mirrors are up dated on the nearly real-time (1 hour) basis. The data access software includes WWW-interface, Perl scripts and C library, which may be linked to a user program. Most of frequently used functions are implemented to make it operable to users without SQL language knowledge. A draft of the data representation standard is suggested, based on common practice of neutron monitor community. The database engine is freely distributed open-sourced PostgreSQL server coupled with a set of replication to ols developed at Bio engineering division of the IRCCS E.Medea, Italy.

Usoskin, I.; Kozlov, Valery; Ksenofontov, Leonid, Kudela, Karel; Starodubtsev, Sergei; Turpanov, Alexey; Yanke, Victor

2003-07-01

300

Cosmic rays in the Milky Way  

NASA Astrophysics Data System (ADS)

One hundred years after Hess' discovery of the radiation coming from space, the main question about the origin of cosmic rays [CRs] is about to be answered. There have been many advances in recent years in both measurements of CRs and in the models describing their acceleration and propagation through the Galaxy. The Milky Way is the best-studied star-forming galaxy, and the only galaxy that direct measurements of CR intensities and spectra are available. Recent observations of diffuse ?-ray emission from other normal galaxies by Fermi opens a possibility to study CR dynamics from the outside, without line-of-sight confusion that hampers interpretation of the diffuse emissions of the Milky Way. I will overview what recently was learned from direct CR experiments and from observations of diffuse emissions arising from various kinds of interactions between CRs and the interstellar medium in our Galaxy.

Moskalenko, Igor V.

2013-02-01

301

Cosmic rays in star-forming galaxies  

NASA Astrophysics Data System (ADS)

The energy density of cosmic ray protons (CRp) in star-forming environments can be (i) measured from ?-ray ?o-decay emission, (ii) inferred from the measured radio non-thermal synchrotron emission (once a theoretical p/e ratio and particle-field equipartition have been assumed), and (iii) estimated from the observed supernova rate and the deduced CRp residency time. For most of the currently available galaxies where these methods can be simultaneously applied, the results of the various methods agree and suggest that CRp energy densities range from Script O(10-1) eV cm-3 in very quiet environments up to Script O(102) eV cm-3 in very active ones. The only case for which the methods do not agree is the Small Magellanic Cloud, where the discrepancy between measured and estimated CRp energy density may be due to a smaller characteristic CR confinement volume.

Persic, Massimo; Rephaeli, Yoel

2012-03-01

302

Two Sources of Cosmic X-rays in Scorpius and Sagittarius  

Microsoft Academic Search

WE have observed two separate and intense sources of cosmic X-rays in the region of the constellations Scorpius and Sagittarius during a rocket experiment launched on August 28, 1964. This is the same general region of the sky from which non-solar cosmic X-rays were first detected in June 1962 by Giacconi et al.1. In that earlier work a Geiger tube

R. Giacconi; H. Gursky; J. R. Waters; G. Clark; B. Rossi

1964-01-01

303

Magnetic Fields and Ultra High Energy Cosmic Rays  

SciTech Connect

The current state and future prospects of ultra high energy cosmic ray physics and the role of magnetic fields in the Galactic and extragalactic medium are reviewed. These cosmic rays with energies well above 1018 eV are messengers of an unknown extremely high-energy universe.

Olinto, Angela V. [Department of Astronomy and Astrophysics, EFI, KICP, University of Chicago, 5640 S. Ellis Ave, Chicago, IL 60637 (United States)

2005-09-28

304

WORLD-WIDE COSMIC-RAY VARIATIONS, 1937–1952  

Microsoft Academic Search

Annual means from continuous registration of cosmic-ray ionizktion at four stations from 1937 to 1952 show a variation of nearly four per cent, which is similar at all stations and which is negatively correlated with sunspot numbers. This variation in cosmic-ray intensity is quite similar for the annual means of all days, international magnetic quiet days, and international magnetic disturbed

Scott E. Forbush

1954-01-01

305

Automatic Recognition of Cosmic Rays at Deep Impact CCDs  

Microsoft Academic Search

The number of cosmic rays on images made by different cameras (HRI VIS, MRI VIS, ITS VIS, HRI IR) during the flight of Deep Impact to Comet Tempel 1 was studied for out-of peak and in the peak (during a flare) of solar activity. Both dark images, which contain only cosmic rays, and normal sky images were considered. We analyzed

S. I. Ipatov; M. F. A'Hearn

2005-01-01

306

THE COSMIC-RAY INTENSITY NEAR THE ARCHEAN EARTH  

SciTech Connect

We employ three-dimensional state-of-the-art magnetohydrodynamic models of the early solar wind and heliosphere and a two-dimensional model for cosmic-ray transport to investigate the cosmic-ray spectrum and flux near the Archean Earth. We assess how sensitive the cosmic-ray spectrum is to changes in the sunspot placement and magnetic field strength, the large-scale dipole magnetic field strength, the wind ram pressure, and the Sun's rotation period. Overall, our results confirm earlier work that suggested the Archean Earth would have experienced a greatly reduced cosmic-ray flux than is the case today. The cosmic-ray reduction for the early Sun is mainly due to the shorter solar rotation period and tighter winding of the Parker spiral, and to the different surface distribution of the more active solar magnetic field. These effects lead to a global reduction of the cosmic-ray flux at 1 AU by up to two orders of magnitude or more. Variations in the sunspot magnetic field have more effect on the flux than variations in the dipole field component. The wind ram pressure affects the cosmic-ray flux through its influence on the size of the heliosphere via the pressure balance with the ambient interstellar medium. Variations in the interstellar medium pressure experienced by the solar system in orbit through the Galaxy could lead to order of magnitude changes in the cosmic-ray flux at Earth on timescales of a few million years.

Cohen, O.; Drake, J. J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Kota, J. [Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721-0092 (United States)

2012-11-20

307

10Be Production in the Atmosphere by Galactic Cosmic Rays  

Microsoft Academic Search

Galactic cosmic ray nuclei and energetic protons produced in solar flares and accelerated by coronal mass ejections are the main sources of high-energy particles of extraterrestrial origin in near-Earth space and inside the Earth's atmosphere. The intensity of galactic cosmic rays inside the heliosphere is strongly influenced by the modulation of the interstellar source particles on their way through interplanetary

Daniel Matthiä; Klaudia Herbst; Bernd Heber; Thomas Berger; Günther Reitz

2011-01-01

308

Propagation and Energy Spectrum of Ultra High Energy Cosmic Rays  

NASA Astrophysics Data System (ADS)

We will review the main physical aspects of Ultra High Energy Cosmic Rays. We will discuss in particular their propagation through astrophysical backgrounds, focusing on the latest experimental observations of HiRes, Telescope Array and Auger. We will also review the issue of the transition between galactic and extra-galactic cosmic rays.

Aloisio, Roberto

2013-06-01

309

Gamma Rays, Cosmic Rays, and Extinct Radioactivity in Molecular Clouds  

Microsoft Academic Search

We investigate causal connection between two astonishingly big numbers: the very large 26Al concentration (5 × 10-5 of 27Al) in the early solar system and the very large nuclear excitation rate in Orion clouds. We present three separate pictures attributing 26Al within the early solar system and other molecular cloud cores to special cosmic-ray irradiation of those cloud cores. These

Donald D. Clayton; Liping Jin

1995-01-01

310

On transmissivity of low energy cosmic rays in disturbed magnetosphere  

NASA Astrophysics Data System (ADS)

Access of low energy cosmic rays to any position on the Earth depends on the state of the magnetosphere. Anisotropy of cosmic rays, deduced from the neutron monitor network, must assume the variable transmissivity of the magnetosphere especially during the geomagnetic disturbances. We illustrate that computations based on different available models of geomagnetic field during selected strong geomagnetic disturbances in 2003 and 2004 imply different profiles of cut-off rigidities in time, different transmissivity functions and different asymptotic directions. Using of cosmic ray records by neutron monitors at middle and low latitudes during geomagnetically active periods, in addition to cosmic ray anisotropy in interplanetary space deduced from high and low energy cosmic ray ground based measurements, may be used for checking validity of geomagnetic field models.

Kudela, K.; Bu?ík, R.; Bobík, P.

2008-10-01

311

Isotropic Variation of Cosmic Ray Intensity During Solar Cycle 21  

NASA Astrophysics Data System (ADS)

High counting rate neutron monitor data have been used to study the isotropic variation of cosmic ray intensity during the interval of 1976-86. Solar and geomagnetic disturbance index data have been obtained from solar geophysical data book(promt report). In this analysis a comparative study have been done to derive the variational trends of different solar,interplanetary and geomagnetic disturbance parameters and their effects on cosmic ray intensity. Cosmic ray inensity shows significant associated changes with solar parameters and does not show significant relationship with geomanetic disturbe index. Correlation between solar wind velocity and cosmic ray intensity is statistically significant.It has been found that the absence of polar coronal holes(PCH) during high solar activity period produces peculier changes in cosmic ray intensity along with interplanatary and geomagnetic disturbance index.

Shrivastava, P. K.

312

Measurements of the Cosmic-Ray Electron Spectrum  

NASA Astrophysics Data System (ADS)

Direct measurements of cosmic-ray electrons and positrons were first made in the early 1960s and since then a number of - mostly balloon borne - instruments were built to study this component of the cosmic radiation. The precise measurement of the intensities of CR electrons and positrons are key to our understanding of cosmic-ray origin and propagation. In addition the locally observed abundance of cosmic ray electrons and/or positrons may exhibit interesting spectral features. Recent reports by the PAMELA team of the observed rise in the cosmic-ray positron fraction above a few GeV and of an excess of cosmic-ray electrons around a few hundred GeV by the ATIC collaboration have resulted in a flurry of publications discussing these observations either as a possible dark matter signature or as a contribution from isolated astrophysical sources. While those interpretations are scientifically exciting, the possibility that measurements are contaminated by misidentified cosmic-ray protons cannot be ignored. This presentation will give a critical assessment of current measurements and discusses upcoming observations by the CREST instrument that will extend the cosmic-ray electron observations into the 10 TeV region.

Schubnell, Michael

2010-02-01

313

Enhancing the High School Physics Experience with Cosmic Ray Research -- The Cosmic Ray Observatory Project (CROP) in Nebraska  

Microsoft Academic Search

The Cosmic Ray Observatory Project (CROP) is a statewide education and research experiment involving Nebraska high school students, teachers, and university undergraduates in the study of extensive cosmic-ray air showers. A network of high school teams construct, install, and operate school-based detectors in coordination with University of Nebraska physics professors and graduate students. The detector system at each school is

Gregory Snow

2007-01-01

314

Tevatron QCD for Cosmic-Rays  

SciTech Connect

The two multi-purpose experiments D0 and CDF are operated at the Tevatron collider, where proton anti-proton collisions take place at a centre of mass energy of 1.96 TeV in Run II. In the kinematic plane of Q{sup 2}-scale and (anti-)proton momentum fraction x, Tevatron jet measurements cover a wide range, with phase space regions in common and beyond the HERA ep-collider reach. The kinematic limit of the Auger experiment is given by a centre of mass energy of 100 TeV. Cosmic rays cover a large region of the kinematic phase space at low momenta x, corresponding to forward proton/diffractive physics and also at low scales, corresponding to the hadronization scale and the underlying event. Therefore of particular interest are exclusive and diffractive measurements as well as underlying event, double parton scattering and minimum bias measurements. The kinematic limit of the Tevatron corresponds to the PeV energy region below the knee of the differential cosmic particle flux energy distribution. The data discussed here are in general corrected for detector effects, such as efficiency and acceptance. Therefore they can be used directly for testing and improving existing event generators and any future calculations/models. Comparisons take place at the hadronic final state (particle level).

Sonnenschein, Lars; /RWTH Aachen U.

2010-12-01

315

The Cosmic Ray Electron Synchrotron Telescope (CREST) Experiment  

NASA Astrophysics Data System (ADS)

CREST is a balloon-borne detector array of barium fluoride crystal scintillators which will measure the intensity and spectrum of multi-TeV electrons in the Cosmic Rays. By detecting the synchrotron photons emitted from electrons passing through the earth's magnetic field, CREST's acceptance is several times its geometric area. We present background measurement results from a small array prototype flight (CREST-I) and describe the full instrument (CREST-II) which is scheduled for an Antarctic Long Duration Balloon flight in late 2009.

Schubnell, M.; Bower, C.; Coutu, S.; et al.

316

Cosmic-ray antiproton constraints on light dark matter candidates  

NASA Astrophysics Data System (ADS)

Some direct detection experiments have recently collected excess events that could be interpreted as a dark matter (DM) signal, pointing to particles in the ~10 GeV mass range. We show that scenarios in which DM can self-annihilate with significant couplings to quarks are likely excluded by the cosmic-ray (CR) antiproton data, provided the annihilation is S-wave dominated when DM decouples in the early universe. These limits applies to most of supersymmetric candidates, e.g. in the minimal supersymmetric standard model (MSSM) and in the next-to-MSSM (NMSSM), and more generally to any thermal DM particle with hadronizing annihilation final states.

Lavalle, Julien

2012-07-01

317

Physics and Fluorescence Detection of Cosmic Ray Air Showers with Energies Between 10^16.5 eV and 10^19 eV  

NASA Astrophysics Data System (ADS)

The Telescope Array (TA) Experiment has been observing cosmic ray air showers at energies above 10^18 eV since 2008. The TA detectors include fluorescence telescopes that look between 3and 33in elevation and a surface array consisting of 507 plastic scintillators layed out on a 1.2km square grid. The TA collaboration is currently installing fluorescence telescopes that look between 33and 59in elevation and starting the construction of a graded infill array of surface detectors spaced at 400m and 600m. With these upgrades, the physics threshold of TA will be lowered to 10^16.5 eV. The TA Low Energy Extension (TALE) will explore the energy regime corresponding to that of the LHC in center-of-mass frame. This is also the range where the transition from galactic to extra- galactic cosmic ray flux is suspected to occur. We will give a brief overview of the physics of TALE, and report on the progress of the new fluorescence telescopes.

Zundel, Zachary

2012-10-01

318

PREFACE: 23rd European Cosmic Ray Symposium (and 32nd Russian Cosmic Ray Conference)  

NASA Astrophysics Data System (ADS)

The 23rd European Cosmic Ray Symposium (ECRS) took place in Moscow at the Lomonosov Moscow State University (3-7 July 2012), and was excellently organized by the Skobeltsyn Institute of Nuclear Physics of the Lomonosov Moscow State University, with the help of the Russian Academy of Sciences and the Council on the Complex Problem of Cosmic Rays of the Russian Academy of Sciences. The first symposia were held in 1968 in Lodz, Poland (high energy, extensive air showers and astrophysical aspects) and in Bern (solar and heliospheric phenomena) and the two 'strands' joined together in 1976 with the meeting in Leeds. Since then the symposia, which have been very successful, have covered all the major topics with some emphasis on European collaborations and on meeting the demands of young scientists. Initially, a driving force was the need to overcome the divisions caused by the 'Cold War' but the symposia continued even when that threat ceased and they have shown no sign of having outlived their usefulness. 2012 has been an important year in the history of cosmic ray studies, in that it marked the centenary of the discovery of enigmatic particles in the perilous balloon ascents of Victor Hess. A number of conferences have taken place in Western Europe during the year, but this one took place in Moscow as a tribute to the successful efforts of many former USSR and other Eastern European scientists in discovering the secrets of the subject, often under very difficult conditions. The symposium covers a wide range of scientific issues divided into the following topics: PCR-IPrimary cosmic rays I (E < 1015 eV) PCR-IIPrimary cosmic rays II (E > 1015 eV) MNCosmic ray muons and neutrinos GAGeV and TeV gamma astronomy SHEnergetic particles in the heliosphere (solar and anomalous CRs and GCR modulation) GEOCosmic rays and geophysics (energetic particles in the atmosphere and magnetosphere of the Earth) On a personal note, as I step down as co-founder and chairman of the International Advisory Committee, I should like to thank those very many colleagues and friends with whom I have had the pleasure of working over the past 45 years. These thanks are extended to the present organizers. The organizers are very grateful to the Russian Foundation of Basic Research and to the Dynasty non-profit foundation for financial support. Arnold Wolfendale

Erlykin, A. D.; Kokoulin, R. P.; Lidvansky, A. S.; Meroshnichenko, L. I.; Panasyuk, M. I.; Panov, A. D.; Wolfendale, A. W.

2013-02-01

319

6Li and Gamma Rays: Complementary Constraints on Cosmic-Ray History  

Microsoft Academic Search

The rare isotope 6Li is made only by cosmic rays, predominantly in alphaalpha-->6Li fusion reactions with interstellar medium (ISM) helium. Consequently, this nuclide provides a unique diagnostic of the history of cosmic rays in our Galaxy. The same hadronic cosmic-ray interactions also produce high-energy gamma-rays (mostly via pp-->pi0-->gammagamma). Thus, hadronic gamma-rays and 6Li are intimately linked. Specifically, 6Li directly encodes

Brian D. Fields; Tijana Prodanovic

2005-01-01

320

The propagation of ultraheavy cosmic ray nuclei  

NASA Astrophysics Data System (ADS)

The propagation of ultraheavy cosmic ray nuclei (Z greater than 30) has been studied using a model based on the leaky-box formalism. This model has been used to examine the possible composition of the source, the path length distribution, and the mean escape length of the confinement region. Various abundance ratios have been found that have a sensitive dependence on one or more of these factors. Comparison of the theoretical values of these ratios with published data suggests that the source composition is similar to that of solar system matter, but that in the Pt-Pb region, enrichment in material produced by the r-process cannot be ruled out. Data for the secondary-to-primary ratio (Ru-44 - Cd-48)/(Sn-50 - Ba-56) show the presence of significantly more secondaries than are predicted, even when a truncated path length distribution is used in the model.

Brewster, N. R.; Freier, P.-S.; Waddington, C. J.

1983-01-01

321

Early Cosmic Ray Research with Balloons  

NASA Astrophysics Data System (ADS)

The discovery of cosmic rays by Victor Hess during a balloon flight in 1912 at an altitude of 5350 m would not have been possible without the more than one hundred years development of scientific ballooning. The discovery of hot air and hydrogen balloons and their first flights in Europe is shortly described. Scientific ballooning was mainly connected with activities of meteorologists. It was also the geologist and meteorologist Franz Linke, who probably observed first indications of a penetrating radiation whose intensity seemed to increase with the altitude. Karl Bergwitz and Albert Gockel were the first physicists studying the penetrating radiation during balloon flights. The main part of the article deals with the discovery of the extraterrestrial radiation by V. Hess and the confirmation by Werner Kolhörster.

Walter, Michael

2013-06-01

322

Cosmic ray transport in strong turbulence  

NASA Astrophysics Data System (ADS)

Recently, several non-linear theories for cosmic ray transport have been proposed to achieve agreement with numerical test particle simulations. Some of these theories, which can be seen as an improvement of quasi-linear theory, agree with simulations. Because recent reports have shown that the perpendicular mean free path could be larger than the parallel mean free path, the assumption of strong turbulence could be reasonable. Therefore, a comparison between different theories and simulations done in the strong turbulence parameter regime for slab/2D composite geometry is presented. It is shown that transport theories and simulations can explain that the perpendicular mean free path can become larger than the parallel mean free path. Further, it is demonstrated that theories cannot reproduce simulations for strong turbulence with high accuracy.

Shalchi, A.

2005-10-01

323

Cosmic-ray muons at ultrahigh energies  

SciTech Connect

Fluxes of cosmic-ray muons were estimated over the energy range extending up to 10{sup 10} GeV. Data on the production of pions; kaons; {eta}, {eta} Prime , {rho}, {omega}, and {phi} mesons; charmed particles; and J/{psi} mesons from accelerator experiments devoted to studying interactions between nucleons and nuclei of air atoms up to nucleon energies of about 2 Multiplication-Sign 10{sup 4} GeV were used in respective calculations. At higher energies, use was made of the results obtained by calculating cross sections for the production of charmed particles and J/{psi} mesons on the basis of QCD models. It is shown that, in interpreting experimental data on extensive air showers, the production of both charmed particles and J/{psi} mesons in the Earth's atmosphere must be taken into account.

Volkova, L. V., E-mail: volkovainr@rambler.ru [Russian Academy of Sciences, Institute for Nuclear Research (Russian Federation)

2011-02-15

324

Cosmic Rays and Terrestrial Planetary Atmospheres  

NASA Astrophysics Data System (ADS)

Planetary atmospheres are constantly irradiated by both photon and particle radiation sources. 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 and photons. Increased ionization leads to changes in atmospheric chemistry, resulting in ozone depletion. This increases the flux of solar UVB radiation at the surface, which is potentially harmful to living organisms. Increased ionization affects the global electrical circuit, which could enhance the low-altitude cloud formation rate. Secondary particles such as muons and thermal neutrons produced as a result of hadronic interactions of the primary cosmic rays with the atmosphere are able to reach the ground, enhancing the biological radiation dose. I will present results obtained from a massive computer simulation using a Monte Carlo code CORSIKA to quantify these effects. Results are available in form of look-up tables for use by the scientific community.

Atri, D.

2011-12-01

325

Developing the Cosmic Ray Veto for ?-SNS  

NASA Astrophysics Data System (ADS)

The newly operational Spallation Neutron Source (SNS) will produce large quanities of neutrinos (˜2x10^7 ?/cm^2/s at 20m) at energies relevant to nuclear astrophysics. To exploit this opportunity, the proposed Neutrinos at the SNS (?-SNS) facility will host 2 detectors (target mass of ˜20 tons each) to measure neutrino-nucleus cross sections for a number of materials (e.g. C, O, Fe, Pb). Shielding the detectors from background is crucial so the facility will employ an iron bunker and a cosmic ray veto. As part of the ?-SNS collaboration, the Colorado School of Mines nuclear group is responsible for the design and construction of this veto. Presented in this talk is the current progress for the research and development of the highly efficient, low cost, large veto panels based on extruded plastic scintillator.

Erikson, L.; Eastburg, J.; Greife, U.

2006-10-01

326

Cosmic Ray Compaction of Porous Interstellar Ices  

NASA Astrophysics Data System (ADS)

We studied the compaction of microporous vapor-deposited ice films under irradiation with different ions in the 80-400 keV energy range. We found that porosity decreases exponentially with irradiation fluence, with a mean compaction area per ion that scales linearly with the stopping power of the projectile S above a threshold St=4 eV Å-1. The experiments roughly follow a universal dependence of ion-induced compaction with restricted dose (eV molecule-1). This behavior can be used to extrapolate our results to conditions of the interstellar medium. Relating our results to ionization rates of interstellar H2, we estimate that porous ice mantles on grains in dense molecular clouds are compacted by cosmic rays in ~10-50 million years.

Raut, U.; Famá, M.; Loeffler, M. J.; Baragiola, R. A.

2008-11-01

327

Plasma Physics of Cosmic Ray Acceleration  

NASA Astrophysics Data System (ADS)

For more than 30 years, first-order Fermi particle acceleration in collisionless shocks has remained the mechanism of choice for producing cosmic rays and other superthermal particle populations in various astrophysical environments. The high efficiency, and therefore nonlinear nature, of the mechanism has presented challenges and surprises for modelers over the years and I will briefly describe some of these. In particular, I will focus on magnetic field amplification and particle escape; two phenomena that highlight the difficult plasma physics involved and which are undergoing active current research. While collisionless shocks, with associated particle acceleration, are believed to exist on scales from the Earth bow shock to galaxy clusters, supernova remnants (SNRs) offer perhaps the best place to study the mechanism. This is the case because several SNRs show extremely broadband continuum emission from radio to TeV gamma rays, sometimes accompanied with thermal X-ray emission. Other aspects, such as the morphology and observed evolution of some young remnants, offer unique clues to fundamental properties of the underlying plasma physics of both the remnant and the coupled acceleration mechanism. I will show how the consistent modeling of SNR observations can result in important constraints on the underlying acceleration mechanism.

Ellison, Donald

2011-04-01

328

Change in cosmic-ray spectrum through the production of electron-positron pairs (analytical approach)  

SciTech Connect

We consider the change in primordial cosmic-ray spectrum through the production of electron-positron pairs in collisions with cosmic microwave background radiation photons. We suggest using these results to estimate the distances to cosmic-ray sources.

Vlasov, V. P., E-mail: vlasov@nfi.kiae.ru; Trubnikov, B. A., E-mail: batrub@nfi.kiae.r [Russian Research Center Kurchatov Institute (Russian Federation)

2009-12-15

329

Solar and Heliospheric Modulation of Galactic Cosmic Rays  

NASA Astrophysics Data System (ADS)

The significance of external influences on the environment of Earth and its atmosphere has become evident during recent years. Especially, on time scales of several hundred years, the cosmogenic isotope concentration during the Wolf-, Spoerer-, Maunder- and Dalton-Minimum indicates an increased cosmic ray flux. Because these grand minima of solar activity coincide with cold periods, a correlation of the Earth climate with the cosmic ray intensities is plausible. Any quantitative study of the effects of energetic particles on the atmosphere and environment of the Earth must address their transport to Earth and their interactions with the Earth’s atmosphere including their filtering by the terrestrial magnetosphere. The first problem is one of the fundamental problems in modern cosmic ray astrophysics, and corresponding studies began in the 1960s based on Parker’s cosmic ray modulation theory taking into account diffusion, convection, adiabatic deceleration, and (later) the drift of energetic particles in the global heliospheric magnetic field. It is well established that all of these processes determining the modulation of cosmic rays are depending on parameters that are varying with the solar magnetic cycle. Therefore, the galactic cosmic ray intensities close to Earth is the result of a complex modulation of the interstellar galactic spectrum within the heliosphere. The modern view of this cosmic ray modulation is summarized in our contribution.

Heber, B.; Fichtner, H.; Scherer, K.

2006-08-01

330

Disentangling cosmic-ray and dark-matter induced ?-rays in galaxy clusters  

NASA Astrophysics Data System (ADS)

Context. Galaxy clusters are among the best targets for indirect dark matter detection in ?-rays, despite the large astrophysical background expected from these objects. Detection is now within reach of current observatories (Fermi-LAT or Cerenkov telescopes); however, assessing the origin of this signal might be difficult. Aims: We investigate whether the behaviour of the number of objects per "flux" bin (log N - log F) and that of the stacked signal could be used as a signature of the dominant process at stake. Methods: We use the Clumpy code to integrate the signal from decaying or annihilating dark matter and from cosmic rays along the line of sight. We assume the standard Navarro-Frenk-White (NFW) profile for the dark matter density and rely on a parametrised emissivity for the cosmic-ray component. In this context, the consequences of stacking are explored using the MCXC meta-catalogue of galaxy clusters. Results: We find the value of the slope of the log N - log F power law (or the increase of the signal with the number of stacked objects) to be a clear diagnosis to disentangle decaying dark matter from cosmic-ray induced ?-rays. For dark matter annihilation, depending on the signal boost from the substructures, it is either similar to the cosmic-ray signal (no boost) or similar to the decay case (large boosts). The shift between the brightest object and its followers also depends on the signal origin. For annihilation, this shift and the stacked signal are poorly constrained because of the large uncertainty affecting the boost. We also underline that the angular dependence of the annihilation signal is not universal because of the substructure contribution.

Maurin, D.; Combet, C.; Nezri, E.; Pointecouteau, E.

2012-11-01

331

Cosmic Ray Composition Studies with the CASA-MIA Detector  

NASA Astrophysics Data System (ADS)

A measurement of the cosmic ray composition in the ``knee'' region of the spectrum (10^14 to 10^16 eV) would provide important information regarding the sources of cosmic rays at these energies. Data from the CASA-MIA (Chicago Air Shower Array and Michigan Muon Array) detector at Dugway, Utah are analyzed using a multi-parameter technique to infer the chemical composition of cosmic rays in this energy region. Such a technique allows the simultaneous use of multiple measured quantities from both the surface and underground portions of the detector to more accurately determine the probable primary compositon. Preliminary results will be presented.

Catanese, M.; Glasmacher, M. A. K.; Matthews, J.; Nitz, D.; Sinclair, D.; van der Velde, J. C.; Borione, A.; Covault, C. E.; Cronin, J. W.; Fick, B. E.; Fortson, L. F.; Gibbs, K. G.; Green, K. D.; Newport, B. J.; Ong, R. A.; Kieda, D. B.

1996-05-01

332

Scattering of cosmic rays by magnetohydrodynamic interstellar turbulence.  

PubMed

Recent advances in understanding of magnetohydrodynamic (MHD) turbulence call for substantial revisions in our understanding of cosmic ray transport. We use recently obtained scalings of MHD modes to calculate the scattering frequency for cosmic rays. We consider gyroresonance with MHD modes (Alfvénic, slow, and fast) and transit-time damping by fast modes. We conclude that the gyroresonance with fast modes is the dominant contribution to cosmic ray scattering for the typical interstellar conditions. In contrast to earlier studies, we find that Alfvénic and slow modes are inefficient because they are far from the isotropy usually assumed. PMID:12513130

Yan, Huirong; Lazarian, A

2002-12-27

333

A cosmic ray cocoon along the X-ray jet of M87?  

NASA Astrophysics Data System (ADS)

Relativistic jets propagating through an ambient medium must produce some observational effects along their side boundaries because of interactions across the large velocity gradient. One possible effect of such an interaction would be a sheared magnetic field structure at the jet boundaries, leading to a characteristic radio polarization pattern. As proposed by Ostrowski, another effect can come from the generation of a high-energy cosmic ray component at the boundary, producing dynamic effects on the medium surrounding the jet and forming a cocoon dominated by cosmic rays with a decreased thermal gas emissivity. We selected this process for our first attempt to look for the effects of this type of interaction. We analysed the Chandra X-ray data for the radio galaxy M87 in order to verify if the expected regions of diminished emissivity may be present near the spectacular X-ray jet in this source. The detailed analysis of the data, merged from 42 separate observations, shows signatures of lower emissivity surrounding the jet. In particular we detect an intensity dip along the part of the jet, which would be approximately 1.5 × 0.15 kpc2 in size, if situated along the jet which is inclined towards us. Due to a highly non-uniform X-ray background in the central region, we are not able to claim the discovery of a cosmic ray cocoon around the M87 jet: we only have demonstrated that the data show morphological structures which could be accounted for if a cosmic ray cocoon exists.

Dainotti, M. G.; Ostrowski, M.; Harris, D.; Siemiginowska, A.; Siejkowski, H.

2012-10-01

334

Relationships between cosmic ray neutron flux and rain flows in dependence on different latitudes and altitudes  

Microsoft Academic Search

A convenient tool for investigation of primary cosmic ray variations is the registration of secondary cosmic ray neutrons. A network of neutron monitors, aiming the studies of cosmic ray variations exists. At the same time cosmic ray variations may be related to some atmospheric processes. In this connection, using the data from Moskow neutron monitor (latitude 55 degree) and lead

Peter Velinov; Anatolii Belov; Viktor Yanke; Evgenia Eroshenko; Alexander Mishev; Yordan Tassev

2008-01-01

335

Peculiar high energy cosmic ray stratospheric event reveals a heavy primary origin particle above the knee region of the cosmic ray spectrum  

SciTech Connect

We wish to put forward an explanation for a peculiar cosmic ray event with energy {sigma}E{sub {gamma}}{>=}2x10{sup 15} eV detected in 1975 by the balloon borne emulsion chamber experiment performed in the stratosphere, at the altitude {>=}30 km above sea level. For almost 30 years the event has been described as unusual, invoking new exotic mechanisms or models. In our opinion there is no need for an extraordinary explanation. Contrary to the widespread belief, the event gives us an example of 'unrecognized standard physics'. At the same time this event revealed a variety of features which are of considerable interest for cosmic rays, nuclear physics, and astrophysics. Here we show that the observed family is most likely to be a result of a heavy nucleus interaction with an air nucleus. In this case a primary particle would originally have been in the energy region above 'the knee' of the cosmic ray spectrum.

Kopenkin, V.; Fujimoto, Y. [Advanced Research Institute for Science and Engineering, Waseda University, Shinjuku, Tokyo, 169 (Japan)

2005-01-15

336

Peculiar high energy cosmic ray stratospheric event reveals a heavy primary origin particle above the knee region of the cosmic ray spectrum  

NASA Astrophysics Data System (ADS)

We wish to put forward an explanation for a peculiar cosmic ray event with energy ?E??2×1015eV detected in 1975 by the balloon borne emulsion chamber experiment performed in the stratosphere, at the altitude ?30km above sea level. For almost 30 years the event has been described as unusual, invoking new exotic mechanisms or models. In our opinion there is no need for an extraordinary explanation. Contrary to the widespread belief, the event gives us an example of “unrecognized standard physics”. At the same time this event revealed a variety of features which are of considerable interest for cosmic rays, nuclear physics, and astrophysics. Here we show that the observed family is most likely to be a result of a heavy nucleus interaction with an air nucleus. In this case a primary particle would originally have been in the energy region above “the knee” of the cosmic ray spectrum.

Kopenkin, V.; Fujimoto, Y.

2005-01-01

337

TOPICAL REVIEW: The origin of the highest energy cosmic rays  

NASA Astrophysics Data System (ADS)

The recent detection of several cosmic ray particle events with energies beyond 0954-3899/23/1/002/img1 eV is challenging current astrophysical theories. The microwave background interacts with high-energy nuclei and protons and thus does not allow particles beyond 0954-3899/23/1/002/img2 eV to reach us from cosmological distances. However, we now have a significant number of clear events of particles with energies beyond this limit. These highest energy cosmic rays cannot be contained in our Galactic disc and therefore ought to originate further outside. In this review we first discuss the boundary conditions for theories to account for these very high-energy particles. The most stringent conditions arise from the space and time possible in any particular scenario for the acceleration, since (a) the Larmor radius scale has to fit clearly inside the system under consideration and (b) the time scale for acceleration needs to be actually available. Then we proceed to discuss the various proposals to explain these high-energy events. Many possible sites for their origin have been proposed, such as the decay of exotic particles, shocks in the large scale structure of the universe, compact objects, Gamma-ray bursts, large scale shocks in our Galactic halo, clusters of galaxies, active galactic nuclei, and, specifically, radio galaxies. This last theory has been worked out in most detail, and therefore ought to be refutable or confirmable in the near future. In any model in which the cosmic rays arrive from nearby cosmological distances, say, from sources related to galaxies, we can make some strong predictions. The clustering of arrival directions in the sky ought to correspond to the source clustering for energies at which intergalactic scattering by magnetic fields is no longer important, and for which the cosmologically local structure of the universe is still inhomogeneous. Above 0954-3899/23/1/002/img3 eV the arrival directions of cosmic rays, as seen by the Haverah Park and Akeno arrays, are no longer isotropic, but appear to partially cluster towards the supergalactic plane, the locus of cosmologically nearby normal galaxies, and radio galaxies. Some local enhancements of the very high-energy cosmic rays may be due to several identifiable radio galaxies; one such candidate is the radio galaxy 3C134. As a corollary we describe a minimalist theory for the origin of magnetic fields in galaxies, deriving them from magnetic stellar winds and stellar dynamos. If the correlation with the supergalactic plane, based here on the Haverah Park and Akeno data, can be verified with the data from future air shower experiments, it would provide strong support for the existence of very energetic nuclei, most likely cosmic ray protons, in sources that cluster cosmologically just as galaxies and radio galaxies do.

Biermann, Peter L.

1997-01-01

338

Understanding TeV-band Cosmic-Ray Anisotropy  

NASA Astrophysics Data System (ADS)

We investigate the temporal and spectral correlations between flux and anisotropy fluctuations of TeV-band cosmic rays in light of recent data taken with IceCube. We find that for a conventional distribution of cosmic-ray sources, the dipole anisotropy is higher than observed, even if source discreteness is taken into account. Moreover, even for a shallow distribution of galactic cosmic-ray sources and a reacceleration model, fluctuations arising from source discreteness provide a probability only of the order of 10% that the cosmic-ray anisotropy limits of the recent IceCube analysis are met. This probability estimate is nearly independent of the exact choice of source rate, but generous for a large halo size. The location of the intensity maximum far from the Galactic Center is naturally reproduced.

Pohl, Martin; Eichler, David

2013-03-01

339

The contribution by Domenico Pacini to the Cosmic Ray Physics  

NASA Astrophysics Data System (ADS)

Between 1900 and 1913 several people were investigating about the unknown radiation, later identified as Cosmic Rays. Several experimentalist tried to identify the origin of this radiation and in particular Victor Franz Hess, Theodor Wulf and Domenico Pacini. Among them Domenico Pacini had a crucial role to address the answer to the origin of this radiation in the right way, and V.F. Hess performed the complete set of measurements that definitively excluded an origin connected to the soil radioactive elements. However the most interesting and may be surprising point it that these pioneers defined 1 century ago the three experimental lines to study the Cosmic Rays: from space, on ground and underground and using only electroscopes. Domenico Pacini in particular may be considered the pioneer of the underground measurements on Cosmic Rays and Hess with his set of systematic measurements with balloon flights, originated the air-space studies on Cosmic Rays.

Giglietto, N.

2011-03-01

340

ASPIRE - Cloud Chambers as an Introduction to Cosmic Ray Observation  

NASA Astrophysics Data System (ADS)

ASPIRE is the K12 - Education & Public Outreach program for the Telescope Array ultra-high energy cosmic ray research project in Utah. The Telescope Array experiment studies ultra-high energy cosmic rays with an array of ˜500 surface scintillator detectors and three fluorescence telescope stations observing over 300 square miles in the West Desert of Utah. Telescope Array is a collaboration of international institutions from the United States, Japan, Korea, Russia and Belgium. Cloud chambers are an inexpensive and easy demonstration to visually observe evidence of charged particles and cosmic ray activity both for informal events as well as for K12 classroom activities. Join us in building a cloud chamber and observe cosmic rays with these table-top demonstrations. A brief overview of the Telescope Array project in Millard County, Utah will also be presented.

Callahan, Julie; Matthews, John; Jui, Charles

2012-03-01

341

Galactic cosmic-ray modulation and solar-terrestrial relationships  

NASA Astrophysics Data System (ADS)

Examples of the recent Italian scientific undertaking on galactic cosmic ray modulation, are given. Current ideas from the international community on long-term effects are discussed. The nucleonic component of primary cosmic rays is the appropriate one to study solar modulation from ground based measurements. Continuous registrations of this component started in the fifties in different sites of the Earth and since then a world wide network of neutron monitors, was established. Nucleonic intensities were recorded since July 1957 at Rome. Only a brief selection among many valuable works related to cosmic rays modulation. Space limitations do not permit a deeper discussion on the subject. Indirect methods to study cosmic ray modulation phenomena emerge from the analysis of cosmogenic nuclei contained in terrestrial and extraterrestrial samples.

Storini, Marisa

1988-10-01

342

Galactic cosmic-ray modulation and solar-terrestrial relationships  

NASA Astrophysics Data System (ADS)

Examples of the recent Italian scientific undertaking on galactic cosmic ray modulation, are given. Current ideas from the international community on long-term effects are discussed. The nucleonic component of primary cosmic rays is the appropriate one to study solar modulation from ground based measurements. Continuous registrations of this component started in the fifties in different sites of the earth, and since then a world wide network of neutron monitors was established. Nucleonic intensities were recorded since July 1957 at Rome. Only a brief selection among many valuable works related to cosmic rays modulation. Space limitations do not permit a deeper discussion on the subject. Indirect methods to study cosmic ray modulation phenomena emerge from the analysis of cosmogenic nuclei contained in terrestrial and extraterrestrial samples.

Storini, M.

1990-02-01

343

Supernova envelope shock origin of cosmic rays: a review  

SciTech Connect

The hydrodynamic shock origin of cosmic rays in the envelope of a Type I presupernova star is reviewed. The possibility of accelerating ultrahigh energy particles to greater than or equal to 10/sup 18/ eV is unique to the shock mechanism and currently no other suggested galactic or extragalactic site is likely. In this paper a review of the work leading to a renewed commitment to the origin of cosmic rays in the shock ejected envelope of supernova is given. The degree to which this interpretation applies to the origin of all cosmic rays is certainly uncertain and does not exclude the possibility of a fraction of the lower energy cosmic rays being accelerated in collisionless plasma shocks in the interstellar medium. 45 references, 3 figures.

Colgate, S.A.

1984-01-01

344

Time Structure of Ground Level and Satellite Cosmic Ray Increases.  

National Technical Information Service (NTIS)

The morphology of solar-related terrestrial cosmic ray increases was studied using neutron-monitor, satellite, and riometer data. Data from numerous events were compared with the power law intensity decay. Results for five ground level increases are mean ...

S. M. Bennett

1964-01-01

345

Progress towards a measurement of the UHE cosmic ray electron flux using the CREST Instrument  

NASA Astrophysics Data System (ADS)

Electrons of energy beyond about 3 TeV have never been detected in the flux of cosmic rays at Earth despite strong evidence of their presence in a number of supernova remnants (e.g., SN 1006). The detection of high energy electrons at Earth would be extremely significant, yielding information about the spatial distribution of nearby cosmic ray sources. With the Cosmic Ray Electron Synchrotron Telescope (CREST), our collaboration has adopted a novel approach to the detection of electrons of energies between 2 and 50 TeV which results in a substantial increase in the acceptance and sensitivity of the apparatus relative to its physics size. The first LDB flight of the CREST detector took place in January 2012, with a float duration of approximately 10 days. In this paper we describe the flight performance of the instrument, and progress in the analysis of the data obtained in this flight.

Musser, Jim; Wakely, Scott; Coutu, Stephane; Geske, Matthew; Nutter, Scott; Tarle, Gregory; Park, Nahee; Schubnell, Michael; Gennaro, Joseph; Muller, Dietrich

2012-07-01

346

Cosmic Ray Ruggedness of Power Semiconductor Devices for Hybrid Vehicles  

NASA Astrophysics Data System (ADS)

Power semiconductors that are used under high voltage conditions in hybrid vehicles (HVs) are required to have a high destruction tolerance against cosmic rays as well as to meet conventional quality standards. In this paper, the failure mechanism for single event burnouts (SEB) induced by cosmic rays in insulated gate bipolar transistors (IGBTs) was investigated. Device destruction tolerance can be greatly improved by adopting an optimized device design that greatly suppresses parasitic thyristor action.

Nishida, Shuichi; Shoji, Tomoyuki; Ohnishi, Toyokazu; Fujikawa, Touma; Nose, Noboru; Ishiko, Masayasu; Hamada, Kimimori

347

Cosmic Rays During the Most-Recent Sunspot Minimum  

NASA Astrophysics Data System (ADS)

During the sunspot minimum between solar cycles 23 and 24, galactic cosmic rays (GCR) reached the highest intensity seen during the spacecraft era. This was due in part to the lower open solar magnetic flux and slower solar wind seen during this period, compared to previous solar minima. The effects of cosmic-ray drifts along the heliospheric current sheet (HCS) has yet to be completely understood; but it is interesting to note that while the HCS was generally not as flat as one might expect given the very quiet Sun, it was at its flattest when the GCR intensity was at its highest. This is important because during this solar magnetic cycle, cosmic-ray protons drift into the heliosphere along the HCS. And, despite the unusually high GCR intensity during this solar minimum, the intensity of anomalous cosmic rays (ACR) was NOT seen to be as high as in previous sunspot minima. Moreover, the GCR electron intensity at the two Voyager spacecraft, which are both approaching the heliopause, is seen to be quite different. These observations lead to important questions regarding the transport of cosmic rays in the heliospheric magnetic field, which originates at the Sun. Particularly important is the transport of cosmic rays across the magnetic field, the role of the heliosheath in cosmic-ray modulation, drifts at the HCS, and the differences between ACRs and GCRs. In this talk, we will review our understanding of cosmic-ray transport in the solar and heliospheric magnetic field and discuss how observations will help resolve these recent puzzles and give constraints on transport parameters.

Giacalone, Joe; Jokipii, Jack; Kota, Jozsef

2012-07-01

348

Extended self-similarity of low-energy cosmic rays  

NASA Astrophysics Data System (ADS)

It is shown that the data on low-energy cosmic rays collected at the Oulu (Northern Finland) neutron monitor after the full-halo coronal mass ejection of July 14, 2000 exhibit well-defined extended self-similarity (ESS) in the time increments interval 0.3 17 hours. Comparison of the energy and ESS spectra of the cosmic-ray intensity fluctuations with those of the solar wind supports the idea of the solar-wind origin of these fluctuations.

Bershadskii, A.

2002-08-01

349

Low energy cosmic ray studies from a lunar base  

NASA Astrophysics Data System (ADS)

Studies of cosmic ray nuclei with energies less than about 7 GeV/nucleon in low earth orbit are hampered by the geomagnetic field. Even in high inclination orbits these effects can be significant. The lunar surface (or lunar orbit) provides an attractive site for carrying out low energy cosmic ray studies which require large detectors. The rationale and requirements for this type of experiment are described.

Wiedenbeck, M. E.

1990-03-01

350

Cosmic Rays During the Most-Recent Sunspot Minimum  

NASA Astrophysics Data System (ADS)

During the sunspot minimum between solar cycles 23 and 24, galactic cosmic rays (GCR) reached the highest intensity seen during the spacecraft era. This was due in part to the lower open solar magnetic flux and slower solar wind seen during this period, compared to previous solar minima. The effects of cosmic-ray drifts along the heliospheric current sheet (HCS) has yet to be completely understood; but it is interesting to note that while the HCS was generally not as flat as one might expect given the very quiet Sun, it was at its flattest when the GCR intensity was at its highest. This is important because during this solar magnetic cycle, cosmic-ray protons drift into the heliosphere along the HCS. And, despite the unusually high GCR intensity during this solar minimum, the intensity of anomalous cosmic rays (ACR) was NOT seen to be as high as in previous sunspot minima. Moreover, the GCR electron intensity at the two Voyager spacecraft, which are both approaching the heliopause, is seen to be quite different. These observations lead to important questions regarding the transport of cosmic rays in the heliospheric magnetic field, which originates at the Sun. Particularly important is the transport of cosmic rays across the magnetic field, the role of the heliosheath in cosmic-ray modulation, drifts at the HCS, and the differences between ACRs and GCRs. In this talk, we will review our understanding of cosmic-ray transport in the solar and heliospheric magnetic field and discuss how observations will help resolve these recent puzzles and give constraints on transport parameters.

Giacalone, J.; Jokipii, J. R.; Kota, J.

2011-12-01

351

A Test of Cosmic Ray Interplanetary Transport Theory  

Microsoft Academic Search

The daughter protons of the energetic neutrons (10-200MeV) produced in the June 3 1982 solar flare are noted as excellent particles for testing cosmic ray interplanetary transport theory. The long-standing discrepancy of about an order of magnitude between theory and observation concerning the cosmic ray transport mean free path in the interplanetary space is also reviewed to show the need

Liwei Dennis Zhang

1994-01-01

352

Wave Coupling in Oblique MHD Cosmic Ray Modified Shocks  

NASA Astrophysics Data System (ADS)

Numerical simulations and multiple scales perturbation methods are used to study wave interactions in magnetohydrodynamics with application to oblique cosmic ray modified shocks. Coupled evolution equations for the Alfven waves, fast and slow magneto-acoustic and entropy waves are solved using a spectral collocation method. Numerical simulations of the fully nonlinear cosmic ray MHD equations are compared to the solutions of the linear wave interaction equations.

Zakharian, Aramais

353

Low-Energy Cosmic-Ray Events Associated with Solar Flares  

Microsoft Academic Search

As a result of the IGY riometer program, it has been found that the measure- ment of ionospheric absorption in arctic regions is a sensitive method of detecting low-energy cosmic rays associated with solar flares. The normal morphology of these events is described, and details are given of the 24 such events that have been detected in the period from

George C. Reid; Harold Leinbach

1959-01-01

354

Performance study of the CMS barrel resistive plate chambers with cosmic rays  

Microsoft Academic Search

In October and November 2008, the CMS collaboration conducted a programme of cosmic ray data taking, which has recorded about 270 million events. The Resistive Plate Chamber system, which is part of the CMS muon detection system, was successfully operated in the full barrel. More than 98% of the channels were operational during the exercise with typical detection efficiency of

S. Chatrchyan; V. Khachatryan; A. M. Sirunyan; W. Adam; B. Arnold; H. Bergauer; T. Bergauer; M. Dragicevic; M. Eichberger; J. Ero; M. Friedl; R. Fruhwirth; V. M. Ghete; J. Hammer; S. Hansel; M. Hoch; N. Hormann; J. Hrubec; M. Jeitler; G. Kasieczka; K. Kastner; M. Krammer; D. Liko; I. M. de Abril; I. Mikulec; F. Mittermayr; B. Neuherz; M. Oberegger; M. Padrta; M. Pernicka; H. Rohringer; S. Schmid; R. Schofbeck; T. Schreiner; R. Stark; H. Steininger; J. Strauss; A. Taurok; F. Teischinger; T. Themel; D. Uhl; P. Wagner; W. Waltenberger; G. Walzel; E. Widl; C. E. Wulz; V. Chekhovsky; O. Dvornikov; I. Emeliantchik; A. Litomin; V. Makarenko; I. Marfin; V. Mossolov; N. Shumeiko; A. Solin; R. Stefanovitch; J. S. Gonzalez; A. Tikhonov; A. Fedorov; A. Karneyeu; M. Korzhik; V. Panov; R. Zuyeuski; P. Kuchinsky; W. Beaumont; L. Benucci; M. Cardaci; E. A. De Wolf; E. Delmeire; D. Druzhkin; M. Hashemi; X. Janssen; T. Maes; L. Mucibello; S. Ochesanu; R. Rougny; M. Selvaggi; H. Van Haevermaet; P. Van Mechelen; N. Van Remortel; V. Adler; S. Beauceron; S. Blyweert; J. DHondt; S. De Weirdt; O. Devroede; J. Heyninck; A. Kalogeropoulos; J. Maes; M. Maes; M. U. Mozer; S. Tavernier; W. Van Doninck; P. Van Mulders; I. Villella; O. Bouhali; E. C. Chabert; O. Charaf; B. Clerbaux; G. De Lentdecker; V. Dero; S. Elgammal; A. P. R. Gay; G. H. Hammad; P. E. Marage; S. Rugovac; C. V. Velde; P. Vanlaer; J. Wickens; M. Grunewald; B. Klein; A. Marinov; D. Ryckbosch; F. Thyssen; M. Tytgat; L. Vanelderen; P. Verwilligen; S. Basegmez; G. Bruno; J. Caudron; C. Delaere; P. Demin; D. Favart; A. Giammanco; G. Gregoire; V. Lemaitre; O. Militaru; S. Ovyn; K. Piotrzkowski; L. Quertenmont; N. Schul; N. Beliy; E. Daubie; G. A. Alves; M. E. Pol; M. H. G. Souza; W. Carvalho; D. D. Damiao; C. D. Martins; S. F. De Souza; L. Mundim; V. Oguri; A. Santoro; S. M. S. Do Amaral; A. Sznajder; Trfp Tomei; M. A. F. Dias; E. M. Gregores; S. F. Novaes; K. Abadjiev; T. Anguelov; J. Damgov; N. Darmenov; L. Dimitrov; V. Genchev; P. Iaydjiev; S. Piperov; S. Stoykova; G. Sultanov; R. Trayanov; I. Vankov; A. Dimitrov; M. Dyulendarova; V. Kozhuharov; L. Litov; E. Marinova; M. Mateev; B. Pavlov; P. Petkov; Z. Toteva; G. M. Chen; H. S. Chen; W. Guan; C. H. Jiang; D. Liang; B. Liu; X. Meng; J. Tao; J. Wang; Z. Wang; Z. Xue; Z. Zhang; Y. Ban; J. Cai; Y. Ge; S. Guo; Z. Hu; Y. Mao; S. J. Qian; H. Teng; B. Zhu; C. Avila; M. B. Ruiz; C. A. C. Montoya; A. Gomez; B. G. Moreno; A. A. O. Rios; A. F. O. Oliveros; D. R. Romero; J. C. Sanabria; N. Godinovic; K. Lelas; R. Plestina; D. Polic; I. Puljak; Z. Antunovic; M. Dzelalija; V. Brigljevic; S. Duric; K. Kadija; S. Morovic; R. Fereos; M. Galanti; J. Mousa; A. Papadakis; F. Ptochos; P. A. Razis; D. Tsiakkouri; Z. Zinonos; A. Hektor; M. Kadastik; K. Kannike; M. Muntel; M. Raidal; L. Rebane; E. Anttila; S. Czellar; J. Harkonen; A. Heikkinen; V. Karimaki; R. Kinnunen; J. Klem; M. J. Kortelainen; T. Lampen; K. Lassila-Perini; S. Lehti; T. Linden; P. Luukka; T. Maenpaa; J. Nysten; E. Tuominen; J. Tuominiemi; D. Ungaro; L. Wendland; K. Banzuzi; A. Korpela; T. Tuuva; P. Nedelec; D. Sillou; M. Besancon; R. Chipaux; M. Dejardin; D. Denegri; J. Descamps; B. Fabbro; J. L. Faure; F. Ferri; S. Ganjour; F. X. Gentit; A. Givernaud; P. Gras; G. H. de Monchenault; P. Jarry; M. C. Lemaire; E. Locci; J. Malcles; M. Marionneau; L. Millischer; J. Rander; A. Rosowsky; D. Rousseau; M. Titov; P. Verrecchia; S. Baffioni; L. Bianchini; M. Bluj; P. Busson; C. Charlot; L. Dobrzynski; R. G. de Cassagnac; M. Haguenauer; P. Mine; P. Paganini; Y. Sirois; C. Thiebaux; A. Zabi; J. L. Agram; A. Besson; D. Bloch; D. Bodin; J. M. Brom; E. Conte; F. Drouhin; J. C. Fontaine; D. Gele; U. Goerlach; L. Gross; P. Juillot; A. C. Le Bihan; Y. Patois; J. Speck; P. Van Hove; C. Baty; M. Bedjidian; J. Blaha; G. Boudoul; H. Brun; N. Chanon; R. Chierici; D. Contardo; P. Depasse; T. Dupasquier; H. El Mamouni; F. Fassi; J. Fay; S. Gascon; B. Ille; T. Kurca; T. Le Grand; M. Lethuillier; N. Lumb; L. Mirabito; S. Perries; M. V. Donckt; P. Verdier; N. Djaoshvili; N. Roinishvili; V. Roinishvili; N. Amaglobeli; R. Adolphi; G. Anagnostou; R. Brauer; W. Braunschweig; M. Edelhoff; H. Esser; L. Feld; W. Karpinski; A. Khomich; K. Klein; N. Mohr; A. Ostaptchouk; D. Pandoulas; G. Pierschel; F. Raupach; S. Schael; A. S. von Dratzig; G. Schwering; D. Sprenger; M. Thomas; M. Weber; B. Wittmer; M. Wlochal; O. Actis; G. Altenhofer; W. Bender; P. Biallass; M. Erdmann; G. Fetchenhauer; J. Frangenheim; T. Hebbeker; G. Hilgers; A. Hinzmann; K. Hoepfner; C. Hof; M. Kirsch; T. Klimkovich; P. Kreuzer; D. Lanske; M. Merschmeyer; A. Meyer; B. Philipps; H. Pieta; H. Reithler; S. A. Schmitz; L. Sonnenschein; M. Sowa; J. Steggemann; H. Szczesny; D. Teyssier; C. Zeidler; M. Bontenackels; M. Davids; M. Duda; G. Flugge; H. Geenen; M. Giffels; W. H. Ahmad; T. Hermanns; D. Heydhausen; S. Kalinin

2010-01-01

355

DO ULTRAHIGH ENERGY COSMIC RAYS COME FROM ACTIVE GALACTIC NUCLEI AND FERMI {gamma}-RAY SOURCES?  

SciTech Connect

We study possible correlations between ultrahigh energy cosmic rays (UHECRs), observed by Auger, AGASA, and Yakutsk, and nearby active galactic nuclei (AGNs) and Fermi sources. We consider the deflection effects by a Galactic magnetic field (GMF) model constrained by the most updated measurements. We found that the average deflection angles of UHECRs by the Galactic magnetic fields are less than 4{sup 0}. A correlation between the Auger cosmic-ray events and nearby AGNs with a significance level of {approx}4{sigma} was found for the Auger UHECR data sets with or without deflection correction. No correlation was found between the AGASA/Yakutsk events with nearby AGNs. Marginal correlations between the Auger events and the Fermi sources, and between AGASA events and Fermi AGNs were found when the deflections calculated by the GMF model were considered. However, no correlation was found between the Yakutsk data and Fermi sources. Some Fermi sources are close to the arrival directions of UHECR events detected by Auger, AGASA, and Yakutsk, most of which are probably chance coincidences rather than objects producing UHECRs in the nearby universe. Four Fermi sources, NGC 4945, ESO 323-G77, NGC 6951, and Cen A, within 100 Mpc have UHECR events within 3.{sup 0}1 from their positions, which could potentially be cosmic-ray accelerators. However, the association can only be confirmed if more UHECRs are preferably detected in these directions.

Jiang Yunying; Hou, L. G.; Han, J. L.; Sun, X. H.; Wang Wei, E-mail: hjl@nao.cas.c [National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100012 (China)

2010-08-10

356

Modulation of Galactic Cosmic Rays at Solar Minimum  

NASA Astrophysics Data System (ADS)

Cosmic ray particles respond to the heliospheric magnetic field in the expanding solar wind and its turbulence and therefore provide a unique probe for conditions in the changing heliosphere. During the last four years, concentrated around the solar minimum period of solar cycle 22, the exploration of the solar polar regions by the joint ESA/NASA mission Ulysses revealed the three-dimensional behavior of cosmic rays in the inner and middle heliosphere. Also during the last decades, the Pioneer and Voyager missions have greatly expanded our understanding of the structure and extent of the outer heliosphere. Simultaneously, numerical models describing the propagation of galactic cosmic rays are becoming sophisticated tools for interpreting and understanding these observations. We give an introduction to the subject of the modulation of galactic cosmic rays in the heliosphere during solar minimum. The modulation effects on cosmic rays of corotating interaction regions and their successors in the outer heliosphere are discussed in more detail by Gazis, McDonald et al. (1999) and McKibben, Jokipii et al. (1999) in this volume. Cosmic-ray observations from the Ulysses spacecraft at high heliographic latitudes are also described extensively in this volume by Kunow, Lee et al. (1999).

Heber, B.; Burger, R. A.

1999-07-01

357

Predicting the response of a submillimeter bolometer to cosmic rays.  

PubMed

Bolometers designed to detect submillimeter radiation also respond to cosmic, gamma, and x rays. Because detectors cannot be fully shielded from such energy sources, it is necessary to understand the effect of a photon or cosmic-ray particle being absorbed. The resulting signal (known as a glitch) can then be removed from raw data. We present measurements using an Americium-241 gamma radiation source to irradiate a prototype bolometer for the High Frequency Instrument in the Planck Surveyor satellite. Our measurements showed no variation in response depending on where the radiation was absorbed, demonstrating that the bolometer absorber and thermistor thermalize quickly. The bolometer has previously been fully characterized both electrically and optically. We find that using optically measured time constants underestimates the time taken for the detector to recover from a radiation absorption event. However, a full thermal model for the bolometer, with parameters taken from electrical and optical measurements, provides accurate time constants. Slight deviations from the model were seen at high energies; these can be accounted for by use of an extended model. PMID:12962375

Woodcraft, Adam L; Sudiwala, Rashmi V; Ade, Peter A R; Griffin, Matthew J; Wakui, Elley; Bhatia, Ravinder S; Lange, Andrew E; Bock, James J; Turner, Anthony D; Yun, Minhee H; Beeman, Jeffrey W

2003-09-01

358

Diffusive cosmic-ray acceleration at the Galactic Centre  

NASA Astrophysics Data System (ADS)

The diffuse TeV emission detected from the inner ˜2° of the Galaxy appears to be strongly correlated with the distribution of molecular gas along the Galactic ridge. Although it is not yet entirely clear whether the origin of the TeV photons is due to hadronic or leptonic interactions, the tight correlation of the intensity distribution with the molecular gas strongly points to a pionic-decay process involving relativistic protons. However, the spectrum of the TeV radiation - a power law with index ??-2.3- cannot be accommodated easily with the much steeper distribution of cosmic rays seen at the Earth. In earlier work, we examined the possible sources of these relativistic protons and concluded that neither the supermassive black hole Sagittarius A*[identified with the High-Energy Stereoscopic System (HESS) source J1745-290] nor several pulsar wind nebulae dispersed along the Galactic plane could produce a TeV emission profile morphologically similar to that seen by the HESS. We concluded from this earlier study that only relativistic protons accelerated throughout the intercloud medium could account for the observed diffuse TeV emission from this region. In this Letter, we develop a model for diffusive proton acceleration driven by a turbulent Alfvénic magnetic field present throughout the gaseous medium. Though circumstantial, this appears to be the first evidence that at least some cosmic rays are accelerated diffusively within the inner ˜300 pc of the Galaxy.

Melia, F.; Fatuzzo, M.

2011-01-01

359

Simulations of black hole air showers in cosmic ray detectors  

SciTech Connect

We present a comprehensive study of TeV black hole events in Earth's atmosphere originated by cosmic rays of very high energy. An advanced fortran Monte Carlo code is developed and used to simulate black hole extensive air showers from ultrahigh-energy neutrino-nucleon interactions. We investigate the characteristics of these events, compare the black hole air showers to standard model air showers, and test different theoretical and phenomenological models of black hole formation and evolution. The main features of black hole air showers are found to be independent of the model considered. No significant differences between models are likely to be observed at fluorescence telescopes and/or ground arrays. We also discuss the tau 'double-bang' signature in black hole air showers. We find that the energy deposited in the second bang is too small to produce a detectable peak. Our results show that the theory of TeV-scale black holes in ultrahigh-energy cosmic rays leads to robust predictions, but the fine prints of new physics are hardly to be investigated through atmospheric black hole events in the near future.

Ahn, Eun-Joo; Cavaglia, Marco [Department of Astronomy and Astrophysics and Kavli Institute for Cosmological Physics, University of Chicago, 5640 S. Ellis Ave, Chicago, Illinois 60637 (United States); Department of Physics and Astronomy, University of Mississippi, University, Mississippi 38677-1848 (United States)

2006-02-15

360

EMMA-a new underground cosmic-ray experiment  

SciTech Connect

An experiment observing underground muons originating from cosmic-ray air showers is under preparation in the Pyhaesalmi mine, Finland. The aim is to cover an area of about 200-300 m{sup 2}, and the detector setup is capable of measuring the muon multiplicity and their lateral distribution. The detector is placed at a depth of about 85 m (corresponding about 240 m w.e.), which gives a threshold energy of muons of about 45 GeV. The detection of the multimuon events is motivated by partly unknown composition of the primary cosmic rays in the energy region of 10{sup 15}-10{sup 16} eV, i.e., the knee region. In addition, by measuring only the higher energy muons of the air shower, the lowest energy muons being filtered out by the rock overburden, the data is sensitive also to the studies of the upper parts of the air shower. The experiment will be constructed mainly using drift chambers used previously in LEP detectors at CERN, but it can also be expanded using plastic scintillator detectors. The prototype detector is expected to be running in the beginning of 2006, and the full-size detector by the end of 2007.

Enqvist, T., E-mail: timo.enqvist@oulu.fi; Foehr, V.; Joutsenvaara, J. [CUPP (Finland); Keraenen, P. [University of Jyvaeskylae, Department of Physics (Finland); Kuusiniemi, P. [CUPP (Finland); Laitala, H.; Lehtola, M.; Mattila, A.; Narkilahti, J.; Nurmenniemi, S.; Peltoniemi, J.; Remes, H.; Raeihae, T. [University of Oulu, CUPP (Finland); Shen, C.; Reponen, M. [CUPP (Finland); Sarkamo, J.; Vaittinen, M. [University of Oulu, CUPP (Finland); Zhang, Z. [CUPP (Finland); Jaemsen, T. [University of Oulu, SGO (Finland); Ding, L. [Chinese Academy of Sciences, IHEP (China)] (and others)

2007-01-15

361

Galactic Cosmic Rays in the Outer Heliosphere  

NASA Astrophysics Data System (ADS)

We report a next generation model of galactic cosmic ray (GCR) transport in the three dimensional heliosphere. Our model is based on an accurate three-dimensional representation of the heliospheric interface. This representation is obtained by taking into account the interaction between partially ionized, magnetized plasma flows of the solar wind and the local interstellar medium. Our model reveal that after entering the heliosphere GCRs are stored in the heliosheath for several years. The preferred GCR entry locations are near the nose of the heliopause and at high latitudes. Low-energy (hundreds of MeV) galactic ions observed in the heliosheath have spent, on average, a longer time in the solar wind than those observed in the inner heliosphere, which would explain their cooled-off spectra at these energies. We also discuss radial gradients in the heliosheath and the implications for future Voyager observations. GCR storage times in different regions of the heliosphere: solar wind (red), heliosheath (green) and heliotail (blue) for an observer at 30 AU (left) and at 100 AU (right).

Florinski, V. A.; Washimi, H.; Pogorelov, N. V.; Adams, J. H.; Zank, G. P.

2010-12-01

362

Development of cosmic ray hardened power MOSFETs  

SciTech Connect

Developmental power DMOS (double-diffused metal-oxide semiconductor) FETs (field effect transistors) were characterized in a simulated cosmic ray environment using heavy ions at the Brookhaven National Laboratory's tandem Van de Graaff accelerator facility. The primary failure mode encountered on FETS in this environment was susceptibility to single event burnout. Burnout of the power DMOS FET was catastrophic. Another failure mode was single event gate rupture. Although gate rupture is not as severe as burnout, its long-term effects are not known. Single event gate rupture causes performance degradation due to increased gate leakage current. An increase in current can pose serious problems to applications that cannot compensate for the added performance degradation. Long-term reliability of the gate oxide may be affected resulting in premature device failure. Each failure mode is discussed. Numerous processing lots were fabricated to experimentally verify that each failure mode could be successfully minimized. Test results show that an n-channel, 150-volt DMOS FET was fabricated that survived exposures to ions with LETs up to 80 MeV-cm{sup 2}/mg. Hardening approaches are discussed, including the advantages and disadvantages of each approach on the FETs performance.

Titus, J.L. (Naval Weapons Support Center, Advanced Technology Div., Crane, IN (US)); Jamiolkowski, L.S.; Wheatley, C.F. (Harris Semiconductor, Mountaintop, PA (US))

1989-12-01

363

The Pamela Cosmic Ray Space Observatory  

NASA Astrophysics Data System (ADS)

PAMELA is a satellite borne experiment designed to study with great accuracy cosmic rays of galactic, solar, and trapped nature in a wide energy range (protons: 80 MeV-700 GeV, electrons 50 MeV-400 GeV). Main objective is the study of the antimatter component: antiprotons (80 MeV-190 GeV), positrons (50 MeV-270 GeV) and search for antimatter with a precision of the order of 10-8). The experiment, housed on board the Russian Resurs-DK1 satellite, was launched on June, 15 2006 in a 350 × 600 km orbit with an inclination of 70 degrees. The detector is composed of a series of scintillator counters arranged at the extremities of a permanent magnet spectrometer to provide charge, Time-of-Flight and rigidity information. Lepton/hadron identification is performed by a Silicon-Tungsten calorimeter and a Neutron detector placed at the bottom of the device. An Anticounter system is used offline to reject false triggers coming from the satellite. In self-trigger mode the Calorimeter, the neutron detector and a shower tail catcher are capable of an independent measure of the lepton component up to 2 TeV. In this work we present some of its scientific results in its first five years of operation.

Casolino, Marco

2013-09-01

364

A Cosmic Ray Telescope For Educational Purposes  

SciTech Connect

Cosmic ray detectors are widely used, for educational purposes, in order to motivate students to the physics of elementary particles and astrophysics. Using a 'telescope' of scintillation counters, the directional characteristics, diurnal variation, correlation with solar activity, can be determined, and conclusions about the composition, origin and interaction of elementary particles with the magnetic field of earth can be inferred. A telescope was built from two rectangular scintillator panels with dimensions: 91.6x1.9x3.7 cm{sup 3}. The scintillators are placed on top of each other, separated by a fixed distance of 34.6 cm. They are supported by a wooden frame which can be rotated around a horizontal axis. Direction is determined by the coincidence of the signals of the two PMTs. Standard NIM modules are used for readout. This device is to be used in the undergraduate nuclear and particle physics laboratory. The design and construction of the telescope as well as some preliminary results are presented.

Voulgaris, G.; Kazanas, S.; Chamilothoris, I. [Department of Physics, National and Kapodistrian University of Athens (Greece)

2010-01-21

365

Cosmic Ray Driven Dynamo in Spiral Galaxies  

NASA Astrophysics Data System (ADS)

We investigate galactic magnetic field generation by means of direct simulations of magnetized ISM composed of ionized gas, magnetic fields and cosmic rays. We consider galactic disk of interstellar matter rotating under time-dependent galactic gravitational potential due to stars and dark matter particles forming disk, bulge and halo. The seed field is assumed to be of stellar origin and is considered to be supplied by supernovae remnants. As a result of underlying CR-driven dynamo process magnetic field is amplified up to the equipartition level. In the present model we note magnetic field reversals and further temporal changes of magnetic field polarity. We find the strongest magnetic field between spiral arms, which is aligned with the arms. In the presence of a galaxy companion galactic magnetic field evolution proceeds analogously until the merger event, after which magnetic field is disordered. For the simple comparison with real observed galaxies we make synthetic maps of synchrotron emission and show similarities to magnetic field structures observed in spiral galaxies such as NGC 6946.

Wólta?ski, Dominik; Hanasz, Micha?; Kowalik, Kacper

366

High energy irradiations simulating cosmic-ray-induced planetary gamma ray production: I. Fe target.  

NASA Astrophysics Data System (ADS)

A series of 6 GeV proton irradiations at the Argonne National Laboratory's Zero Gradient Synchrocyclotron included the bombardment of two thick Fe targets for the purpose of simulating the cosmic ray bombardment of planetary objects in space. Cosmic ray bombardment leads to characteristic gamma ray production, from which, by measuring their energy and intensity, surface composition may be derived.

Metzger, A. E.; Parker, R. H.; Yellin, J.

1986-03-01

367

Cosmic Ray Anomalies from the MSSM?  

SciTech Connect

The recent positron excess in cosmic rays (CR) observed by the PAMELA satellite may be a signal for dark matter (DM) annihilation. When these measurements are combined with those from FERMI on the total (e{sup +} + e{sup -}) ux and from PAMELA itself on the {anti p}p ratio, these and other results are difficult to reconcile with traditional models of DM, including the conventional minimal Supergravity (mSUGRA) version of Supersymmetry even if boosts as large as 10{sup 3-4} are allowed. In this paper, we combine the results of a previously obtained scan over a more general 19-parameter subspace of the Minimal Supersymmetric Standard Model (MSSM) with a corresponding scan over astrophysical parameters that describe the propagation of CR. We then ascertain whether or not a good fit to this CR data can be obtained with relatively small boost factors while simultaneously satisfying the additional constraints arising from gamma ray data. We find that a specific subclass of MSSM models where the Lightest Supersymmetric Particle (LSP) is mostly pure bino and annihilates almost exclusively into {tau} pairs comes very close to satisfying these requirements. The lightest in this set of models is found to be relatively close in mass to the LSP and is in some cases the nLSP. These models lead to a significant improvement in the overall fit to the data by {approx}1 unit of {chi}{sup 2}/dof in comparison to the best fit without Supersymmetry while employing boosts in the range {approx}100-200. The implications of these models for future experiments are discussed.

Cotta, R.C.; /SLAC; Conley, J.A.; /Bonn U.; Gainer, J.S.; /Argonne /Northwestern U.; Hewett, J.L.; Rizzo, T.G.; /SLAC

2011-08-11

368

Detectability of the first cosmic explosions  

NASA Astrophysics Data System (ADS)

We present a fully self-consistent simulation of a synthetic survey of the furthermost cosmic explosions. The appearance of the first generation of stars (Population III) in the Universe represents a critical point during cosmic evolution, signalling the end of the dark ages, a period of absence of light sources. Despite their importance, there is no confirmed detection of Population III stars so far. A fraction of these primordial stars are expected to die as pair-instability supernovae (PISNe), and should be bright enough to be observed up to a few hundred million years after the big bang. While the quest for Population III stars continues, detailed theoretical models and computer simulations serve as a testbed for their observability. With the upcoming near-infrared missions, estimates of the feasibility of detecting PISNe are not only timely but imperative. To address this problem, we combine state-of-the-art cosmological and radiative simulations into a complete and self-consistent framework, which includes detailed features of the observational process. We show that a dedicated observational strategy using ? 8 per cent of the total allocation time of the James Webb Space Telescope mission can provide us with up to ˜9-15 detectable PISNe per year.

de Souza, R. S.; Ishida, E. E. O.; Johnson, J. L.; Whalen, D. J.; Mesinger, A.

2013-10-01

369

Cosmic-Ray Positron Energy Spectrum Measured by PAMELA.  

PubMed

Precision measurements of the positron component in the cosmic radiation provide important information about the propagation of cosmic rays and the nature of particle sources in our Galaxy. The satellite-borne experiment PAMELA has been used to make a new measurement of the cosmic-ray positron flux and fraction that extends previously published measurements up to 300 GeV in kinetic energy. The combined measurements of the cosmic-ray positron energy spectrum and fraction provide a unique tool to constrain interpretation models. During the recent solar minimum activity period from July 2006 to December 2009, approximately 24?500 positrons were observed. The results cannot be easily reconciled with purely secondary production, and additional sources of either astrophysical or exotic origin may be required. PMID:24010424

Adriani, O; Barbarino, G C; Bazilevskaya, G A; Bellotti, R; Bianco, A; Boezio, M; Bogomolov, E A; Bongi, M; Bonvicini, V; Bottai, S; Bruno, A; Cafagna, F; Campana, D; Carbone, R; Carlson, P; Casolino, M; Castellini, G; De Donato, C; De Santis, C; De Simone, N; Di Felice, V; Formato, V; Galper, A M; Karelin, A V; Koldashov, S V; Koldobskiy, S A; Krutkov, S Y; Kvashnin, A N; Leonov, A; Malakhov, V; Marcelli, L; Martucci, M; Mayorov, A G; Menn, W; Mergé, M; Mikhailov, V V; Mocchiutti, E; Monaco, A; Mori, N; Munini, R; Osteria, G; Palma, F; Papini, P; Pearce, M; Picozza, P; Pizzolotto, C; Ricci, M; Ricciarini, S B; Rossetto, L; Sarkar, R; Scotti, V; Simon, M; Sparvoli, R; Spillantini, P; Stochaj, S J; Stockton, J C; Stozhkov, Y I; Vacchi, A; Vannuccini, E; Vasilyev, G I; Voronov, S A; Yurkin, Y T; Zampa, G; Zampa, N; Zverev, V G

2013-08-19

370

Cosmic Rays in Extragalactic Systems: Clusters and Beyond  

NASA Astrophysics Data System (ADS)

The existence of cosmic rays (CRs) accelerated outside our galaxy is by now established fact. For instance, the angular and spectral distributions of ultra high energy CRs (UHECRs) above roughly an EeV point clearly to their extragalactic origins. Diffuse nonthermal radio emis-sions in clusters and along their perimeters reveal GeV electrons filling volumes sometimes approaching Mpc scales. The radiative lifetimes of those leptonic CRs are so short that they must be accelerated or produced as secondaries in situ. The dominant energy sources for such extragalactic CRs are not clearly established, although they are likely to be consequences of strucure formation. Large-scale shocks (including cluster accretion shocks) and turbulence in-duced by structure formation are strong candidates. There is also the possibility that CRs may be produced through structure formation process on still larger scales associated with cos-mic filaments, although current evidence for that is sketchy. The effectiveness of processes in these environments that might accelerate CRs depends sensitively on poorly understood "mi-crophysics" in very dilute and weakly magnetized plasmas. All of these CR populations have the potential to produce diagnostic gamma rays in the GeV to TeV range. Consequently, detec-tion or improved detection limits by current and coming gamma ray observatories can provide unique and crucial information about physical processes and conditions in these environments. My talk will outline the current status of these issues. This work is supported by the US NSF, NASA and by the Minnesota Supercomputing Institute.

Jones, Thomas

371

Cosmic Topological Defects, Highest Energy Cosmic Rays, and the Baryon Asymmetry of the Universe  

NASA Astrophysics Data System (ADS)

It is pointed out that the observed extremely high energy cosmic rays (EHECR) above 1011 GeV and the observed baryon asymmetry of the Universe (BAU) may have a common origin in baryon number violating decays of supermassive X particles released from cosmic topological defects (TDs) such as cosmic strings and monopoles. The X particles produced by TDs in the recent epochs produce the EHECR, while the BAU is created by X particles released from TDs mainly in the very early Universe. In this scenario the EHECR is predicted to contain baryons as well as antibaryons with a small asymmetry between the two.

Bhattacharjee, Pijushpani

1998-07-01

372

Alteration of Organic Compounds in Small Bodies and Cosmic Dusts by Cosmic Rays and Solar Radiation  

NASA Astrophysics Data System (ADS)

A wide variety of complex organic compounds have been detected in extraterrestrial bodies like carbonaceous chondrites and comets, and their roles in the generation of terrestrial life are discussed. It was suggested that organics in small bodies were originally formed in ice mantles of interstellar dusts in dense cloud. Irradiation of frozen mixture of possible interstellar molecules including CO (or CH _{3}OH), NH _{3} and H _{2}O with high-energy particles gave complex amino acid precursors with high molecular weights [1]. Such complex organic molecules were taken in planetesimals or comets in the early solar system. In prior to the generation of the terrestrial life, extraterrestrial organics were delivered to the primitive Earth by such small bodies as meteorites, comets and space dusts. These organics would have been altered by cosmic rays and solar radiation (UV, X-rays) before the delivery to the Earth. We examined possible alteration of amino acids, their precursors and nucleic acid bases in interplanetary space by irradiation with high energy photons and heavy ions. A mixture of CO, NH _{3} and H _{2}O was irradiated with high-energy protons from a van de Graaff accelerator (TIT, Japan). The resulting products (hereafter referred to as CAW) are complex precursors of amino acids. CAW, amino acids (dl-Isovaline, glycine), hydantoins (amino acid precursors) and nucleic acid bases were irradiated with continuous emission (soft X-rays to IR; hereafter referred to as soft X-rays irradiation) from BL-6 of NewSUBARU synchrotron radiation facility (Univ. Hyogo). They were also irradiated with heavy ions (eg., 290 MeV/u C ^{6+}) from HIMAC accelerator (NIRS, Japan). After soft X-rays irradiation, water insoluble materials were formed. After irradiation with soft X-rays or heavy ions, amino acid precursors (CAW and hydantoins) gave higher ratio of amino acids were recovered after hydrolysis than free amino acids. Nucleic acid bases showed higher stability than free amino acids. Complex amino acid precursors with high molecular weights could be formed in simulated dense cloud environments. They would have been altered in the early solar system by irradiation with soft X-rays from the young Sun, which caused increase of hydrophobicity of the organics of interstellar origin. They were taken up by parent bodies of meteorites or comets, and could have been delivered to the Earth by meteorites, comets and cosmic dusts. Cosmic dusts were so small that they were directly exposed to the solar radiation, which might be critical for the survivability of organics in them. In order to evaluate the roles of space dusts as carriers of bioorganic compounds to the primitive Earth, we are planning the Tanpopo Mission, where collection of cosmic dusts by using ultra low-density aerogel, and exposure of amino acids and their precursors for years are planned by utilizing the Japan Experimental Module / Exposed Facility of the ISS [2]. The mission is now scheduled to start in 2013. We thank Dr. Katsunori Kawasaki of Tokyo Institute of Technology, and Dr. Satoshi Yoshida of National Institute of Radiological Sciences for their help in particles irradiation. We also thank to the members of JAXA Tanpopo Working Group (PI: Prof. Akihiko Yamagishi) for their helpful discussion. [1] K. Kobayashi, et al., in ``Astrobiology: from Simple Molecules to Primitive Life,'' ed. by V. Basiuk, American Scientific Publishers, Valencia, CA, (2010), pp. 175-186. [2] K. Kobayashi, et al., Trans. Jpn. Soc. Aero. Space Sci., in press (2012).

Kobayashi, Kensei; Kaneko, Takeo; Mita, Hajime; Obayashi, Yumiko; Takahashi, Jun-ichi; Sarker, Palash K.; Kawamoto, Yukinori; Okabe, Takuto; Eto, Midori; Kanda, Kazuhiro

2012-07-01

373

The Consequences of the Cosmic Star Formation Rate: X-Ray Number Counts  

Microsoft Academic Search

We discuss the observable consequences for the detection of galaxies in the X-ray bandpass resulting from a peak in the cosmic star formation rate at a redshift greater than 1. Following N. White and P. Ghosh, we assume a large evolution in the X-ray\\/B luminosity ratio at z~0.5-1.5 resulting from the X-ray binaries that have evolved from stars formed at

A. Ptak; R. Griffiths; N. White; P. Ghosh

2001-01-01

374

Medium scale anisotropy in the TeV cosmic ray flux observed by ARGO-YBJ  

NASA Astrophysics Data System (ADS)

Measuring the anisotropy of the arrival direction distribution of cosmic rays provides important information on the propagation mechanisms and the identification of their sources. In fact, the flux of cosmic rays is thought to be dependent on the arrival direction only due to the presence of nearby cosmic ray sources or particular magnetic-field structures. Recently, the observation of unexpected excesses at TeV energy down to an angular scale as narrow as ˜10° raised the possibility that the problem of the origin of Galactic cosmic rays may be addressed by studying the anisotropy. The ARGO-YBJ experiment is a full-coverage extensive air showers array, sensitive to cosmic rays with the energy threshold of a few hundred GeV. Searching for small-size deviations from the isotropy, the ARGO-YBJ Collaboration explored the declination region ?˜-20°-80°, making use of about 3.7×1011 events collected from November 2007 to May 2012. In this paper, the detection of different significant (up to 13 standard deviations) medium-scale anisotropy regions in the arrival directions of cosmic rays is reported. The observation was performed with unprecedented detail. The relative excess intensity with respect to the isotropic flux extends up to 10-3. The maximum excess occurs for proton energies of 10-20 TeV, suggesting the presence of unknown features of the magnetic fields the charged cosmic rays propagate through, or some contribution of nearby sources never considered so far. The observation of new weaker few-degree excesses throughout the sky region 195°?R.A.?290° is reported for the first time.

Bartoli, B.; Bernardini, P.; Bi, X. J.; Bolognino, I.; Branchini, P.; Budano, A.; Calabrese Melcarne, A. K.; Camarri, P.; Cao, Z.; Cardarelli, R.; Catalanotti, S.; Chen, S. Z.; Chen, T. L.; Creti, P.; Cui, S. W.; Dai, B. Z.; D'Amone, A.; Danzengluobu; De Mitri, I.; D'Ettorre Piazzoli, B.; Di Girolamo, T.; Di Sciascio, G.; Feng, C. F.; Feng, Zhaoyang; Feng, Zhenyong; Gou, Q. B.; Guo, Y. Q.; He, H. H.; Hu, Haibing; Hu, Hongbo; Iacovacci, M.; Iuppa, R.; Jia, H. Y.; Labaciren; Li, H. J.; Liguori, G.; Liu, C.; Liu, J.; Liu, M. Y.; Lu, H.; Ma, X. H.; Mancarella, G.; Mari, S. M.; Marsella, G.; Martello, D.; Mastroianni, S.; Montini, P.; Ning, C. C.; Panareo, M.; Panico, B.; Perrone, L.; Pistilli, P.; Ruggieri, F.; Salvini, P.; Santonico, R.; Sbano, S. N.; Shen, P. R.; Sheng, X. D.; Shi, F.; Surdo, A.; Tan, Y. H.; Vallania, P.; Vernetto, S.; Vigorito, C.; Wang, H.; Wu, C. Y.; Wu, H. R.; Xue, L.; Yan, Y. X.; Yang, Q. Y.; Yang, X. C.; Yao, Z. G.; Yuan, A. F.; Zha, M.; Zhang, H. M.; Zhang, L.; Zhang, X. Y.; Zhang, Y.; Zhaxiciren; Zhaxisangzhu; Zhou, X. X.; Zhu, F. R.; Zhu, Q. Q.; Zizzi, G.

2013-10-01

375

Cosmic ray proton spectrum determined with the imaging atmospheric Cherenkov technique  

Microsoft Academic Search

The HEGRA system of 4 imaging atmospheric Cherenkov telescopes (IACTs) has been used to determine the flux and the spectrum of cosmic ray protons over a limited energy range around 1.5 TeV. Although the IACT system is designed for the detection of gamma-rays with energies above 500 GeV, it has also a large detection area of ~=106 m2×3 msr for

F. Aharonian; A. G. Akhperjanian; J. A. Barrio; A. S. Belgarian; K. Bernlöhr; J. J. G. Beteta; H. Bojahr; S. Bradbury; I. Calle; J. L. Contreras; J. Cortina; A. Daum; T. Deckers; S. Denninghoff; V. Fonseca; J. C. Gonzalez; G. Heinzelmann; M. Hemberger; G. Hermann; M. Hess; A. Heusler; W. Hofmann; H. Hohl; I. Holl; D. Horns; A. Ibarra; R. Kankanyan; M. Kestel; O. Kirstein; C. Köhler; A. Konopelko; H. Kornmeyer; D. Kranich; H. Krawczynski; H. Lampeitl; A. Lindner; E. Lorenz; N. Magnussen; H. Meyer; R. Mirzoyan; A. Moralejo; L. Padilla; M. Panter; D. Petry; R. Plaga; A. Plyasheshnikov; J. Prahl; C. Prosch; G. Pühlhofer; G. Rauterberg; C. Renault; W. Rhode; A. Röhring; V. Sahakian; M. Samorski; D. Schmele; F. Schröder; W. Stamm; H. J. Völk; B. Wiebel-Sooth; C. A. Wiedner; M. Willmer; H. Wirth

1999-01-01

376

Acceleration of Cosmic Rays at Large Scale Cosmic Shocks in the Universe  

NASA Astrophysics Data System (ADS)

Cosmological hydrodynamic simulations of large scale structure in the universe have shown that accretion shocks and merger shocks form due to flow motions associated with the gravitational collapse of nonlinear structures. Estimated speed and curvature radius of these shocks could be as large as a few 1000 km/s and several Mpc, respectively. According to the diffusive shock acceleration theory, populations of cosmic-ray particles can be injected and accelerated to very high energy by astrophysical shocks in tenuous plasmas. In order to explore the cosmic ray acceleration at the cosmic shocks, we have performed nonlinear numerical simulations of cosmic ray (CR) modified shocks with the newly developed CRASH (Cosmic Ray Amr SHock) numerical code. We adopted the Bohm diffusion model for CRs, based on the hypothesis that strong Alfvén waves are self-generated by streaming CRs. The shock formation simulation includes a plasma-physics-based ``injection'' model that transfers a small proportion of the thermal proton flux through the shock into low energy CRs for acceleration there. We found that, for strong accretion shocks, CRs can absorb most of shock kinetic energy and the accretion shock speed is reduced up to 20 %, compared to pure gas dynamic shocks. For merger shocks with small Mach numbers, however, the energy transfer to CRs is only about 10-20 % with an associated CR particle fraction of 10(-3) . Nonlinear feedback due to the CR pressure is insignificant in the latter shocks. Although detailed results depend on models for the particle diffusion and injection, these calculations show that cosmic shocks in large scale structure could provide acceleration sites of extragalactic cosmic rays of the highest energy.

Kang, Hyesung; Jones, T. W.

2002-12-01

377

Cosmic-ray muons in the deep ocean  

SciTech Connect

A string of seven optical detectors deployed from a ship was used to detect the Cherenkov light from muons at ocean depths ranging from 2000 to 4000 m in intervals of {similar to}500 m. The flux and angular distributions of cosmic-ray muons were measured. An effective area for fivefold coincidences of 420 m{sup 2} for downward-going muons was achieved. The results are consistent with those derived from underground observations and theoretical calculations. The measured vertical intensity ranges from (9.84{plus minus}6.5){times}10{sup {minus}8} cm{sup {minus}2} s{sup {minus}1} sr{sup {minus}1} at 2090 m of water equivalent (mwe) to (4.57{plus minus}1.37){times}10{sup {minus}9} cm{sup {minus}2} s{sup {minus}1} sr{sup {minus}1} at 4157 mwe.

Babson, J.; Barish, B.; Becker-Szendy, R.; Bradner, H.; Cady, R.; Clem, J.; Dye, S.T.; Gaidos, J.; Gorham, P.; Grieder, P.K.F.; Jaworski, M.; Kitamura, T.; Kropp, W.; Learned, J.G.; Matsuno, S.; March, R.; Mitsui, K.; O'Connor, D.; Ohashi, Y.; Okada, A.; Peterson, V.; Price, L.; Reines, F.; Roberts, A.; Roos, C.; Sobel, H.; Stenger, V.J.; Webster, M.; Wilson, C. (University of Bern, Bern (Switzerland) California Institute of Technology, Pasadena, CA (USA) University of California at Irvine, Irvine, CA (USA) University of California at San Diego, La Jolla, CA (USA) Hawaii DUMAND Center, University of Hawaii, Honolulu, HI (USA) Purdue University, Layfayette, IN (USA) Institute for Cosmic Ray Research, University of Tokyo, Tokyo (Japan) Vanderbilt University, Nashville, TN (USA) University of Wisconsin, Madison, WI (USA)); DUMAND Collaboration

1990-12-01

378

Upper limit on the antihelium flux in primary cosmic rays  

NASA Astrophysics Data System (ADS)

The explanation of the observed baryon asymmetry, i.e., the almost complete absence of antimatter in the visible part of the universe, is one of the most important problems in cosmology. The real asymmetry value can be determined by direct measurements of the fluxes of antinuclei with charges | Z| ? 2 in primary cosmic rays near the Earth. The results of the search for antihelium using data from the PAMELA experiment obtained from June 2006 to December 2009 are presented. No events with a charge of -2 have been detected in the rigidity range of 0.6-600 GV. An upper limit on the antihelium/helium flux ratio \\overline {He} /He has been presented as a function of the energy. An integral upper level of 4.7 × 10-7 is the lowest limit at rigidities above 14 GV.

Mayorov, A. G.; Galper, A. M.; Adriani, O.; Bazilevskaya, G. A.; Barbarino, G.; Bellotti, R.; Boezio, M.; Bogomolov, E. A.; Bonvicini, V.; Bongi, M.; Bonechi, L.; Borisov, S. V.; Bottai, S.; Bruno, A.; Vacci, S.; Vannuccini, E.; Vasiliev, G. I.; Voronov, S. A.; Wu, Y.; Danilchenko, I. A.; Gillard, W.; Jerse, G.; Zampa, G.; Zampa, N.; Zverev, V. G.; Casolino, M.; Campana, D.; Carbone, R.; Karelin, A. V.; Carlson, P.; Castellini, G.; Cafagna, F.; Kvashnin, A. N.; Koldashov, S. V.; Koldobsky, S. A.; Krutkov, S. Yu.; Leonov, A. A.; Malakhov, V. V.; Malvezzi, V.; Marcelli, L.; Menn, W.; Mikhailov, V. V.; Mocchiutti, E.; Mori, N.; Nikonov, N. V.; Osteria, G.; Pizzolotto, S.; Papini, P.; De Pascale, M. P.; Picozza, P.; Pearce, M.; Ricci, M.; Ricciarini, S.; Runtso, M. F.; Simon, M.; De Simone, N.; Sparvoli, R.; Spillantini, P.; Stozhkov, Yu. I.; Di Felice, V.; Yurkin, Yu. T.

2011-08-01

379

Commissioning of the ATLAS Muon Spectrometer with cosmic rays  

NASA Astrophysics Data System (ADS)

The ATLAS detector at the Large Hadron Collider has collected several hundred million cosmic ray events during 2008 and 2009. These data were used to commission the Muon Spectrometer and to study the performance of the trigger and tracking chambers, their alignment, the detector control system, the data acquisition and the analysis programs. We present the performance in the relevant parameters that determine the quality of the muon measurement. We discuss the single element efficiency, resolution and noise rates, the calibration method of the detector response and of the alignment system, the track reconstruction efficiency and the momentum measurement. The results show that the detector is close to the design performance and that the Muon Spectrometer is ready to detect muons produced in high energy proton-proton collisions.

Aad, G.; Abbott, B.; Abdallah, J.; Abdelalim, A. A.; Abdesselam, A.; Abdinov, O.; Abi, B.; Abolins, M.; Abramowicz, H.; Abreu, H.; Acharya, B. S.; Adams, D. L.; Addy, T. N.; Adelman, J.; Adorisio, C.; Adragna, P.; Adye, T.; Aefsky, S.; Aguilar-Saavedra, J. A.; Aharrouche, M.; Ahlen, S. P.; Ahles, F.; Ahmad, A.; Ahmed, H.; Ahsan, M.; Aielli, G.; Akdogan, T.; Åkesson, T. P. A.; Akimoto, G.; Akimov, A. V.; Aktas, A.; Alam, M. S.; Alam, M. A.; Albrand, S.; Aleksa, M.; Aleksandrov, I. N.; Alexa, C.; Alexander, G.; Alexandre, G.; Alexopoulos, T.; Alhroob, M.; Aliev, M.; Alimonti, G.; Alison, J.; Aliyev, M.; Allport, P. P.; Allwood-Spiers, S. E.; Almond, J.; Aloisio, A.; Alon, R.; Alonso, A.; Alviggi, M. G.; Amako, K.; Amelung, C.; Amorim, A.; Amorós, G.; Amram, N.; Anastopoulos, C.; Andeen, T.; Anders, C. F.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Anduaga, X. S.; Angerami, A.; Anghinolfi, F.; Anjos, N.; Annovi, A.; Antonaki, A.; Antonelli, M.; Antonelli, S.; Antos, J.; Antunovic, B.; Anulli, F.; Aoun, S.; Arabidze, G.; Aracena, I.; Arai, Y.; Arce, A. T. H.; Archambault, J. P.; Arfaoui, S.; Arguin, J.-F.; Argyropoulos, T.; Arik, M.; Armbruster, A. J.; Arnaez, O.; Arnault, C.; Artamonov, A.; Arutinov, D.; Asai, M.; Asai, S.; Asfandiyarov, R.; Ask, S.; Åsman, B.; Asner, D.; Asquith, L.; Assamagan, K.; Astbury, A.; Astvatsatourov, A.; Atoian, G.; Auerbach, B.; Augsten, K.; Aurousseau, M.; Austin, N.; Avolio, G.; Avramidou, R.; Axen, D.; Ay, C.; Azuelos, G.; Azuma, Y.; Baak, M. A.; Bach, A. M.; Bachacou, H.; Bachas, K.; Backes, M.; Badescu, E.; Bagnaia, P.; Bai, Y.; Bain, T.; Baines, J. T.; Baker, O. K.; Baker, M. D.; Baker, S.; Dos Santos Pedrosa, F. Baltasar; Banas, E.; Banerjee, P.; Banerjee, S.; Banfi, D.; Bangert, A.; Bansal, V.; Baranov, S. P.; Baranov, S.; Barashkou, A.; Barber, T.; Barberio, E. L.; Barberis, D.; Barbero, M.; Bardin, D. Y.; Barillari, T.; Barisonzi, M.; Barklow, T.; Barlow, N.; Barnett, B. M.; Barnett, R. M.; Baroncelli, A.; Barr, A. J.; Barreiro, F.; Barreiro Guimarães da Costa, J.; Barrillon, P.; Bartoldus, R.; Bartsch, D.; Bates, R. L.; Batkova, L.; Batley, J. R.; Battaglia, A.; Battistin, M.; Bauer, F.; Bawa, H. S.; Bazalova, M.; Beare, B.; Beau, T.; Beauchemin, P. H.; Beccherle, R.; Becerici, N.; Bechtle, P.; Beck, G. A.; Beck, H. P.; Beckingham, M.; Becks, K. H.; Beddall, A. J.; Beddall, A.; Bednyakov, V. A.; Bee, C.; Begel, M.; Harpaz, S. Behar; Behera, P. K.; Beimforde, M.; Belanger-Champagne, C.; Bell, P. J.; Bell, W. H.; Bella, G.; Bellagamba, L.; Bellina, F.; Bellomo, M.; Belloni, A.; Belotskiy, K.; Beltramello, O.; Ben Ami, S.; Benary, O.; Benchekroun, D.; Bendel, M.; Benedict, B. H.; Benekos, N.; Benhammou, Y.; Benincasa, G. P.; Benjamin, D. P.; Benoit, M.; Bensinger, J. R.; Benslama, K.; Bentvelsen, S.; Beretta, M.; Berge, D.; Bergeaas Kuutmann, E.; Berger, N.; Berghaus, F.; Berglund, E.; Beringer, J.; Bernat, P.; Bernhard, R.; Bernius, C.; Berry, T.; Bertin, A.; Besana, M. I.; Besson, N.; Bethke, S.; Bianchi, R. M.; Bianco, M.; Biebel, O.; Biesiada, J.; Biglietti, M.; Bilokon, H.; Bindi, M.; Binet, S.; Bingul, A.; Bini, C.; Biscarat, C.; Bitenc, U.; Black, K. M.; Blair, R. E.; Blanchard, J.-B.; Blanchot, G.; Blocker, C.; Blondel, A.; Blum, W.; Blumenschein, U.; Bobbink, G. J.; Bocci, A.; Boehler, M.; Boek, J.; Boelaert, N.; Böser, S.; Bogaerts, J. A.; Bogouch, A.; Bohm, C.; Bohm, J.; Boisvert, V.; Bold, T.; Boldea, V.; Bondarenko, V. G.; Bondioli, M.; Boonekamp, M.; Bordoni, S.; Borer, C.; Borisov, A.; Borissov, G.; Borjanovic, I.; Borroni, S.; Bos, K.; Boscherini, D.; Bosman, M.; Boterenbrood, H.; Bouchami, J.; Boudreau, J.; Bouhova-Thacker, E. V.; Boulahouache, C.; Bourdarios, C.; Boveia, A.; Boyd, J.; Boyko, I. R.; Bozovic-Jelisavcic, I.; Bracinik, J.; Braem, A.; Branchini, P.; Brandenburg, G. W.; Brandt, A.; Brandt, G.; Brandt, O.; Bratzler, U.; Brau, B.; Brau, J. E.; Braun, H. M.; Brelier, B.; Bremer, J.; Brenner, R.; Bressler, S.; Britton, D.; Brochu, F. M.; Brock, I.; Brock, R.; Brodet, E.; Bromberg, C.; Brooijmans, G.; Brooks, W. K.; Brown, G.; Bruckman de Renstrom, P. A.; Bruncko, D.; Bruneliere, R.; Brunet, S.; Bruni, A.; Bruni, G.; Bruschi, M.; Bucci, F.; Buchanan, J.; Buchholz, P.; Buckley, A. G.; Budagov, I. A.; Budick, B.; Büscher, V.; Bugge, L.; Bulekov, O.; Bunse, M.; Buran, T.; Burckhart, H.; Burdin, S.; Burgess, T.; Burke, S.; Busato, E.; Bussey, P.; Buszello, C. P.; Butin, F.; Butler, B.; Butler, J. M.; Buttar, C. M.; Butterworth, J. M.; Byatt, T.; Caballero, J.; Cabrera Urbán, S.; Caforio, D.; Cakir, O.; Calafiura, P.; Calderini, G.; Calfayan, P.; Calkins, R.; Caloba, L. P.; Calvet, D.; Camarri, P.; Cameron, D.; Campana, S.; Campanelli, M.; Canale, V.; Canelli, F.; Canepa, A.; Cantero, J.; Capasso, L.; Capeans Garrido, M. D. M.

2010-12-01

380

Search for antimatter with the AMS cosmic ray detector  

NASA Astrophysics Data System (ADS)

Antimatter search results of the Alpha Magnetic Spectrometer (AMS) detector are presented. About 108 triggers were collected in the 1998 precursor flight onboard space shuttle Discovery. This ten day mission exposed the detector on a 51.7° orbit at an altitude around 350km. Identification of charged cosmic rays is achieved by multiple energy loss and time-of-flight measurements. Bending inside the 0.15T magnetic volume yields a measurement of the absolute value of the particle's rigidity. The supplemental knowledge of the sense of traversal identifies the sign of the charge. In the rigidity range 1 < R < 140 GV no antinucleus at any rigidity was detected, while 2.86 × 106 helium and 1.65 × 105 heavy nuclei were precisely measured. Hence, upper limits on the flux ratio Zbar/Z are given. Different prior assumptions on the antimatter spectrum are considered and corresponding limits are given.

Cristinziani, Markus

2003-01-01

381

Cosmic-ray Propagation and Interactions in the Galaxy  

SciTech Connect

We survey the theory and experimental tests for the propagation of cosmic rays in the Galaxy up to energies of 10{sup 15} eV. A guide to the previous reviews and essential literature is given, followed by an exposition of basic principles. The basic ideas of cosmic-ray propagation are described, and the physical origin of its processes are explained. The various techniques for computing the observational consequences of the theory are described and contrasted. These include analytical and numerical techniques. We present the comparison of models with data including direct and indirect--especially gamma-ray--observations, and indicate what we can learn about cosmic-ray propagation. Some particular important topics including electrons and antiparticles are chosen for discussion.

Strong, Andrew W.; /Garching, Max Planck Inst., MPE; Moskalenko, Igor V.; /Stanford U., HEPL /KIPAC, Menlo Park; Ptuskin, Vladimir S.; /Troitsk, IZMIRAN

2007-01-22

382

CMS data processing workflows during an extended cosmic ray run  

Microsoft Academic Search

The CMS Collaboration conducted a month-long data taking exercise, the Cosmic Run At Four Tesla, during October-November 2008, with the goal of commissioning the experiment for extended operation. With all installed detector systems participating, CMS recorded 270 million cosmic ray events with the solenoid at a magnetic field strength of 3.8 T. This paper describes the data flow from the

S. Chatrchyan; V. Khachatryan; A. M. Sirunyan; W. Adam; B. Arnold; H. Bergauer; T. Bergauer; M. Dragicevic; M. Eichberger; J. Ero; M. Friedl; R. Fruhwirth; V. M. Ghete; J. Hammer; S. Hansel; M. Hoch; N. Hormann; J. Hrubec; M. Jeitler; G. Kasieczka; K. Kastner; M. Krammer; D. Liko; I. M. de Abril; I. Mikulec; F. Mittermayr; B. Neuherz; M. Oberegger; M. Padrta; M. Pernicka; H. Rohringer; S. Schmid; R. Schofbeck; T. Schreiner; R. Stark; H. Steininger; J. Strauss; A. Taurok; F. Teischinger; T. Themel; D. Uhl; P. Wagner; W. Waltenberger; G. Walzel; E. Widl; C. E. Wulz; V. Chekhovsky; O. Dvornikov; I. Emeliantchik; A. Litomin; V. Makarenko; I. Marfin; V. Mossolov; N. Shumeiko; A. Solin; R. Stefanovitch; J. S. Gonzalez; A. Tikhonov; A. Fedorov; A. Karneyeu; M. Korzhik; V. Panov; R. Zuyeuski; P. Kuchinsky; W. Beaumont; L. Benucci; M. Cardaci; E. A. De Wolf; E. Delmeire; D. Druzhkin; M. Hashemi; X. Janssen; T. Maes; L. Mucibello; S. Ochesanu; R. Rougny; M. Selvaggi; H. Van Haevermaet; P. Van Mechelen; N. Van Remortel; V. Adler; S. Beauceron; S. Blyweert; J. DHondt; S. De Weirdt; O. Devroede; J. Heyninck; A. Kalogeropoulos; J. Maes; M. Maes; M. U. Mozer; S. Tavernier; W. Van Doninck; P. Van Mulders; I. Villella; O. Bouhali; E. C. Chabert; O. Charaf; B. Clerbaux; G. De Lentdecker; V. Dero; S. Elgammal; A. P. R. Gay; G. H. Hammad; P. E. Marage; S. Rugovac; C. V. Velde; P. Vanlaer; J. Wickens; M. Grunewald; B. Klein; A. Marinov; D. Ryckbosch; F. Thyssen; M. Tytgat; L. Vanelderen; P. Verwilligen; S. Basegmez; G. Bruno; J. Caudron; C. Delaere; P. Demin; D. Favart; A. Giammanco; G. Gregoire; V. Lemaitre; O. Militaru; S. Ovyn; K. Piotrzkowski; L. Quertenmont; N. Schul; N. Beliy; E. Daubie; G. A. Alves; M. E. Pol; M. H. G. Souza; W. Carvalho; D. D. Damiao; C. D. Martins; S. F. De Souza; L. Mundim; V. Oguri; A. Santoro; S. M. S. Do Amaral; A. Sznajder; Trfp Tomei; M. A. F. Dias; E. M. Gregores; S. F. Novaes; K. Abadjiev; T. Anguelov; J. Damgov; N. Darmenov; L. Dimitrov; V. Genchev; P. Iaydjiev; S. Piperov; S. Stoykova; G. Sultanov; R. Trayanov; I. Vankov; A. Dimitrov; M. Dyulendarova; V. Kozhuharov; L. Litov; E. Marinova; M. Mateev; B. Pavlov; P. Petkov; Z. Toteva; G. M. Chen; H. S. Chen; W. Guan; C. H. Jiang; D. Liang; B. Liu; X. Meng; J. Tao; J. Wang; Z. Wang; Z. Xue; Z. Zhang; Y. Ban; J. Cai; Y. Ge; S. Guo; Z. Hu; Y. Mao; S. J. Qian; H. Teng; B. Zhu; C. Avila; M. B. Ruiz; C. A. C. Montoya; A. Gomez; B. G. Moreno; A. A. O. Rios; A. F. O. Oliveros; D. R. Romero; J. C. Sanabria; N. Godinovic; K. Lelas; R. Plestina; D. Polic; I. Puljak; Z. Antunovic; M. Dzelalija; V. Brigljevic; S. Duric; K. Kadija; S. Morovic; R. Fereos; M. Galanti; J. Mousa; A. Papadakis; F. Ptochos; P. A. Razis; D. Tsiakkouri; Z. Zinonos; A. Hektor; M. Kadastik; K. Kannike; M. Muntel; M. Raidal; L. Rebane; E. Anttila; S. Czellar; J. Harkonen; A. Heikkinen; V. Karimaki; R. Kinnunen; J. Klem; M. J. Kortelainen; T. Lampen; K. Lassila-Perini; S. Lehti; T. Linden; P. Luukka; T. Maenpaa; J. Nysten; E. Tuominen; J. Tuominiemi; D. Ungaro; L. Wendland; K. Banzuzi; A. Korpela; T. Tuuva; P. Nedelec; D. Sillou; M. Besancon; R. Chipaux; M. Dejardin; D. Denegri; J. Descamps; B. Fabbro; J. L. Faure; F. Ferri; S. Ganjour; F. X. Gentit; A. Givernaud; P. Gras; G. H. de Monchenault; P. Jarry; M. C. Lemaire; E. Locci; J. Malcles; M. Marionneau; L. Millischer; J. Rander; A. Rosowsky; D. Rousseau; M. Titov; P. Verrecchia; S. Baffioni; L. Bianchini; M. Bluj; P. Busson; C. Charlot; L. Dobrzynski; R. G. de Cassagnac; M. Haguenauer; P. Mine; P. Paganini; Y. Sirois; C. Thiebaux; A. Zabi; J. L. Agram; A. Besson; D. Bloch; D. Bodin; J. M. Brom; E. Conte; F. Drouhin; J. C. Fontaine; D. Gele; U. Goerlach; L. Gross; P. Juillot; A. C. Le Bihan; Y. Patois; J. Speck; P. Van Hove; C. Baty; M. Bedjidian; J. Blaha; G. Boudoul; H. Brun; N. Chanon; R. Chierici; D. Contardo; P. Depasse; T. Dupasquier; H. El Mamouni; F. Fassi; J. Fay; S. Gascon; B. Ille; T. Kurca; T. Le Grand; M. Lethuillier; N. Lumb; L. Mirabito; S. Perries; M. Vander Donckt; P. Verdier; N. Djaoshvili; N. Roinishvili; V. Roinishvili; N. Amaglobeli; R. Adolphi; G. Anagnostou; R. Brauer; W. Braunschweig; M. Edelhoff; H. Esser; L. Feld; W. Karpinski; A. Khomich; K. Klein; N. Mohr; A. Ostaptchouk; D. Pandoulas; G. Pierschel; F. Raupach; S. Schael; A. S. von Dratzig; G. Schwering; D. Sprenger; M. Thomas; M. Weber; B. Wittmer; M. Wlochal; O. Actis; G. Altenhofer; W. Bender; P. Biallass; M. Erdmann; G. Fetchenhauer; J. Frangenheim; T. Hebbeker; G. Hilgers; A. Hinzmann; K. Hoepfner; C. Hof; M. Kirsch; T. Klimkovich; P. Kreuzer; D. Lanske; M. Merschmeyer; A. Meyer; B. Philipps; H. Pieta; H. Reithler; S. A. Schmitz; L. Sonnenschein; M. Sowa; J. Steggemann; H. Szczesny; D. Teyssier; C. Zeidler; M. Bontenackels; M. Davids; M. Duda; G. Flugge; H. Geenen; M. Giffels; W. H. Ahmad; T. Hermanns; D. Heydhausen; S. Kalinin

2010-01-01

383

Cosmic ray feedback in hydrodynamical simulations of galaxy formation  

NASA Astrophysics Data System (ADS)

It is well known that cosmic rays contribute significantly to the pressure of the interstellar medium in our own Galaxy, suggesting that they may play an important role in regulating star formation during the formation and evolution of galaxies. We here discuss a novel numerical treatment of the physics of cosmic rays and its implementation in the parallel smoothed particle hydrodynamics code GADGET-2. In our methodology, the non-thermal cosmic ray population of each gaseous fluid element is approximated by a simple power law spectrum in particle momentum, characterized by an amplitude, a cut-off, and a fixed slope. Adiabatic compression and a number of physical source and sink terms are modelled which modify the cosmic ray pressure of each particle. The most important sources considered are injection by supernovae and diffusive shock acceleration, while the primary sinks are thermalization by Coulomb interactions, and catastrophic losses by hadronic interactions. We also include diffusion of cosmic rays. Using a number of test problems, we show that our scheme is numerically robust and efficient, allowing us to carry out the first cosmological structure formation simulations that account for cosmic ray physics, together with radiative cooling and star formation. In simulations of isolated galaxies, we find that cosmic rays can significantly reduce the star formation efficiencies of small galaxies, with virial velocities below 80 km s-1, an effect that becomes progressively stronger towards low-mass scales. In cosmological simulations of the formation of dwarf galaxies at high redshift, we find that the total mass-to-light ratio of small halos and the faint end of the luminosity function are affected. The latter becomes slightly flatter. When cosmic ray acceleration in shock waves is followed as well, we find that up to 40% of the energy dissipated at structure formation shocks can appear as cosmic ray pressure at redshifts around z˜ 3{-}6, but this fraction drops to 10% at low redshifts when the shock distribution becomes increasingly dominated by lower Mach numbers. Despite this large cosmic ray energy content in the high-redshift intergalactic medium, the flux power spectrum of the Lyman-? forest is only affected on very small scales of k>0.1 km-1s, and at a weak level of 5{-}15%. Within virialized objects, we find lower contributions of CR-pressure, due to the increased efficiency of loss processes at higher densities, the lower Mach numbers of shocks inside halos, and the softer adiabatic index of CRs, which disadvantages them when a composite of thermal gas and cosmic rays is adiabatically compressed. The total energy in cosmic rays relative to the thermal energy within the virial radius drops from 20% for 1012 h-1 {M}_? halos to 5% for rich galaxy clusters of mass 1015 h-1 {M}_? in non-radiative simulations. Interestingly, the lower effective adiabatic index also increases the compressibility of the intrahalo medium, an effect that slightly increases the central concentration of the gas and the baryon fraction within the virial radius. We find that this can enhance the cooling rate onto central cluster galaxies, even though the galaxies in the cluster periphery become slightly less luminous as a result of cosmic ray feedback.

Jubelgas, M.; Springel, V.; Enßlin, T.; Pfrommer, C.

2008-04-01

384

Nineteenth International Cosmic Ray Conference. HE Sessions, volume 6  

SciTech Connect

Papers contributed to the 19th International Cosmic Ray Conference which address high energy interactions and related phenomena are compiled. Particular topic areas include cross sections; particle production; nuclei and nuclear matter; nucleus-nucleus collisions; gamma ray and hadron spectra; C-jets, a-jets, and super families; and emulsion chamber simulations.

Jones, F.C.

1985-08-01

385

Recent results from VERITAS on VHE gamma rays and cosmic rays  

NASA Astrophysics Data System (ADS)

VERITAS is a major ground-based detector of very high energy (VHE, energy greater than 100 GeV) gamma rays and cosmic rays. Consisting of an array of four 12m-diameter atmospheric Cherenkov telescopes, VERITAS has been fully operational since September 2007. VERITAS has detected many astrophysical sources of VHE gamma rays, including, recently, the discovery of VHE emission from Tycho's Supernova remnant, from the Cygnus OB 1 region, from the CTA1 Supernova remnant, and from the Crab pulsar. In 2009, VERITAS was upgraded by relocation of one of the telescopes, leading to a significant improvement in sensitivity. A program to further improve the performance of VERITAS is now underway, in which the telescope trigger systems and the telescope cameras will be upgraded. This upgrade will lead to a lower energy threshold and a greater collection area for VERITAS, allowing it to make more sensitive observations of known galactic and extragalactic sources and to detect fainter and more distant sources. This talk will describe recent results from VERITAS, with an emphasis on those aspects that relate to the origin of cosmic rays.

Ong, Rene

2012-07-01

386

Estimates of galactic cosmic ray shielding requirements during solar minimum  

NASA Astrophysics Data System (ADS)

Estimates of radiation risk from galactic cosmic rays are presented for manned interplanetary missions. The calculations use the Naval Research Laboratory cosmic ray spectrum model as input into the Langley Research Center galactic cosmic ray transport code. This transport code, which transports both heavy ions and nucleons, can be used with any number of layers of target material, consisting of up to five different arbitrary constituents per layer. Calculated galactic cosmic ray fluxes, dose and dose equivalents behind various thicknesses of aluminum, water and liquid hydrogen shielding are presented for the solar minimum period. Estimates of risk to the skin and the blood-forming organs (BFO) are made using 0-cm and 5-cm depth dose/dose equivalent values, respectively, for water. These results indicate that at least 3.5 g/sq cm (3.5 cm) of water, or 6.5 g/sq cm (2.4 cm) of aluminum, or 1.0 g/sq cm (14 cm) of liquid hydrogen shielding is required to reduce the annual exposure below the currently recommended BFO limit of 0.5 Sv. Because of large uncertainties in fragmentation parameters and the input cosmic ray spectrum, these exposure estimates may be uncertain by as much as a factor of 2 or more. The effects of these potential exposure uncertainties or shield thickness requirements are analyzed.

Townsend, Lawrence W.; Nealy, John E.; Wilson, John W.; Simonsen, Lisa C.

1990-02-01

387

Cosmic ray anisotropies to 5 PeV  

NASA Astrophysics Data System (ADS)

Several large cosmic ray (CR) detectors have recently provided data on the arrival directions of CR, which taken together with previous data recorded over many decades allow the amplitude and phase of the first harmonic to be derived with reasonable precision and up to higher energies. We find a high degree of consistency amongst the various measurements. The new data indicate that at an energy above ~ 0.1 PeV a change of the CR anisotropy sets in. The amplitude of the first harmonic, which rises to 3 TeV, then diminishes and begins to rise again. The direction of the phase also changes to the opposite one. A measure of understanding follows from the use of two-dimensional maps of cosmic ray excesses over the mean background. When the energy of cosmic rays approaches the PeV region, the excess of cosmic rays moves from the Galactic Anti-Centre to the opposite direction of the Galactic Centre. The possible role of such potential cosmic ray sources as the supernovae Monogem Ring and Vela, which could help to explain some of the observed results, is discussed.

Erlykin, A. D.; Wolfendale, A. W.

2013-04-01

388

Ineffectiveness of Narrow CMEs for Cosmic Ray Modulation  

NASA Astrophysics Data System (ADS)

Monthly coronal mass ejection (CME) counts, - for all CMEs and CMEs with widths > 30?, - and monthly averaged speeds for the events in these two groups were compared with both the monthly averaged cosmic ray intensity and the monthly sunspot number. The monthly P i-index, which is a linear combination of monthly CME count rate and average speed, was also compared with the cosmic ray intensity and sunspot number. The main finding is that narrow CMEs, which were numerous during 2007 - 2009, are ineffective for modulation. A cross-correlation analysis, calculating both the Pearson ( r) product-moment correlation coefficient and the Spearman ( ?) rank correlation coefficient, has been used. Between all CMEs and cosmic ray intensity we found correlation coefficients r=- 0.49 and ?=- 0.46, while between CMEs with widths > 30? and cosmic ray intensity we found r=- 0.75 and ?=- 0.77, which implies a significant increase. Finally, the best expression for the P i-index for the examined period was analyzed. The highly anticorrelated behavior among this CME index, the cosmic ray intensity ( r=- 0.84 and ?=- 0.83), and the sunspot number ( r=+ 0.82 and ?=+ 0.89) suggests that the first one is a very useful solar-heliospheric parameter for heliospheric and space weather models in general.

Paouris, Evangelos

2013-06-01

389

Atmospheric cosmic rays and solar energetic particles at aircraft altitudes.  

PubMed

Galactic cosmic rays, which are thought to be produced and accelerated by a variety of mechanisms in the Milky Way galaxy, interact with the solar wind, the earth's magnetic field, and its atmosphere to produce hadron, lepton, and photon fields at aircraft altitudes that are quite unlike anything produced in the laboratory. The energy spectra of these secondary particles extend from the lowest possible energy to energies over an EeV. In addition to cosmic rays, energetic particles, generated on the sun by solar flares or coronal mass ejections, bombard the earth from time to time. These particles, while less energetic than cosmic rays, also produce radiation fields at aircraft altitudes which have qualitatively the same properties as cosmic rays. The authors have calculated atmospheric cosmic-ray angular fluxes, spectra, scalar fluxes, and ionization, and compared them with experimental data. Agreement with these data is seen to be good. These data have been used to calculate equivalent doses in a simplified human phantom at aircraft altitudes and the estimated health risks to aircraft crews. The authors have also calculated the radiation doses from several large solar energetic particle events (known as GLEs, or Ground Level Events), which took place in 1989, including the very large event known as GLE 42, which took place on September 29th and 30th of that year. The spectra incident on the atmosphere were determined assuming diffusive shock theory. Unfortunately, there are essentially no experimental data with which to compare these calculations. PMID:11542509

O'Brien, K; Friedberg, W; Sauer, H H; Smart, D F

1996-01-01

390

A ready-to-use galactic cosmic ray model  

NASA Astrophysics Data System (ADS)

Galactic cosmic ray nuclei close to Earth are of great importance in different fields of research. By studying their intensity in near-Earth interplanetary space and modeling their modulation in the heliosphere it is possible to gain knowledge both about the structure of the heliosphere and the transport processes within. Additionally, secondary phenomena like cloud formation, ionization processes in the atmosphere, cosmogenic nuclide production and radiation exposure in space and at aviation altitudes are related to the intensity of the galactic cosmic rays and their modulation in the heliosphere. In order to improve the knowledge about these processes and underlying mechanisms it is often beneficial to perform numerical simulations. A necessary prerequisite for such simulations is a model describing the galactic cosmic ray intensities for all particle types and energies of importance. Several of these models exist in the literature. However, many of these do not provide essential characteristics like the description of heavier nuclei or it is difficult to associate them to recent or actual solar modulation conditions. In this work a model is presented which describes the galactic cosmic ray spectra of nuclei based on a single parameter. The values of this parameter for different solar modulation conditions are derived from measurements of the Advanced Composition Explorer (ACE) spacecraft and Oulu neutron monitor count rates. Comparing the galactic cosmic ray spectra predicted by the model to a comprehensive set of experimental data from literature shows very good agreement.

Matthiä, Daniel; Berger, Thomas; Mrigakshi, Alankrita I.; Reitz, Günther

2013-02-01

391

The possible mechanism of galactic cosmic rays variability action on the hurricanes development  

NASA Astrophysics Data System (ADS)

The galactic cosmic rays effect on atmosphere is usually considered from the point of view of cosmic rays variability correlation with the global cloud coverage. And from this point of view it is unambiguously treated as a negative effect on the ground temperature due to decreasing of atmosphere transparency. At the same time a lot of latent heat is released due to formation of condensation nuclei on the ions produced by cosmic rays ionization of atmospheric gases. The maximum of ionization profile is near the tropopause altitude, so at this altitude the cosmic rays effect should be considered as positive. Instead of statistical correlation the short-term variations of cosmic rays intensity (Forbush decreases) can be used to check the temperature variability at the tropopause altitude. It was detected that such variations can reach up to 9 degrees Celsius as it happened during initial stage of development of the hurricane Katrina on days 25-26 of August 2005. This temperature decrease increased the temperature difference between the ocean surface and tropopause, and consequently increased the convective instability. Some estimates presented showing the effectiveness of the ionization in the heat production and increasing of vertical convection.

Pulinets, Sergey

392

Particle-in-cell simulation of astrophysical plasmas: Probing the origin of cosmic rays  

NASA Astrophysics Data System (ADS)

Cosmic rays, the product of natural extraterrestrial particle accelerators far more powerful than the LHC, were first detected a century ago. A "standard model" of cosmic-ray acceleration in supernova remnants has begun to emerge, but a number of questions still require satisfactory answers. The maximum particle energy attainable via the most favored mechanism, diffusive shock acceleration, is limited by the amplitude of magnetic-field turbulence in the unshocked interstellar or circumstellar medium, but cosmic rays are observed at high enough energies that some magnetic-field amplification is required. By what mechanisms might this amplification occur, and can it operate to a great enough extent to account for those cosmic rays thought to be of Galactic origin? A number of proposed solutions involve instabilities arising from interactions between cosmic rays and the upstream plasma, whose evolution becomes highly nonlinear. A related question explored is whether the presence of accelerated particles in the shock vicinity has any microscopic effect on the instabilities governing the shock itself. Particle-in-cell kinetic simulations allow us to investigate the growth and saturation of these instabilities at the (astrophysically) microscopic scale, providing valuable insights and important considerations for self-consistent macroscopic models of particle acceleration.

Stroman, Thomas Alan

393

High energy irradiations simulating cosmic-ray-induced planetary gamma ray production: I. Fe target  

NASA Astrophysics Data System (ADS)

A series of 6 GeV proton irradiations at the Argonne National Laboratory's Zero Gradient Synchrocyclotron included the bombardment of two thick Fe targets for the purpose of simulating the cosmic ray bombardment of planetary objects in space. Cosmic ray bombardment leads to characteristic gamma ray production, from which, by measuring their energy and intensity, surface composition may be derived. In this experiment, gamma ray energy spectra were obtained with a germanium solid state detector during the bombardment. The spectra show much detail, with 46 of the gamma ray lines ascribed to the Fe targets. The background includes recoil-broadened lines due to energetic neutron interactions in the Ge detector. A comparison with values predicted by modeling shows good agreement for Fe lines from neutron inelastic scattering and spallation reactions, and less satisfactory agreement for neutron capture reactions, the latter found to be due primarily to the difference in composition between the Fe target and the mean lunar abundance used in the modeling. Analysis of the irradiation results combined with continuum data obtained in lunar orbit indicates that 100 hours of measurement with a state-of-the-art instrument should generate a spectrum containing approximately 20 lines due to Fe alone, with a 2? sensitivity for detection of about 0.2%.

Metzger, Albert E.; Parker, Richard H.; Yellin, Joseph

1986-09-01

394

Medipix/Timepix cosmic ray tracking on BEXUS stratospheric balloon flights  

NASA Astrophysics Data System (ADS)

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.

Urbar, J.; Scheirich, J.; Jakubek, J.

2011-05-01

395

Supernova Remnants Interacting with Molecular Clouds:. a New way to Reveal Cosmic Rays  

NASA Astrophysics Data System (ADS)

Molecular clouds interact with the ambient cosmic rays. The decay of secondary particles may give rise to a detectable flux of very high-energy photons. Recently the H.E.S.S., MAGIC and VERITAS telescopes have observed such sources associated with large molecular clouds and shell-type supernova remnants. Emission lines of OH masers are also observed in coincidence. This ensures that the expanding wave front of the supernova interacts effectively with the cloud. Such natural configurations bring new material to confront with the hypothesis that supernova remnants are the Galactic cosmic-ray accelerators. We describe the approach towards a systematic observation of such associations, present the current data and review the prospects of these studies for answering the question of the origin of the Galactic cosmic rays.

Feinstein, F.; Fiasson, A.

2011-03-01

396

Black holes through cosmic time: Exploring the distant X-ray Universe with extragalactic Chandra surveys  

Microsoft Academic Search

Extragalactic X-ray surveys are exceptionally powerful tools for studying the evolution of supermassive black holes and their host galaxies, by detecting large numbers of active galactic nuclei (AGN) and star-forming galaxies over a wide range of redshifts and cosmic environments. With its sensitivity and superb angular resolution, Chandra has been at the forefront of recent extragalactic surveys. This article provides

Ryan C. Hickox

2009-01-01

397

Commissioning and performance of the CMS silicon strip tracker with cosmic ray muons  

Microsoft Academic Search

During autumn 2008, the Silicon Strip Tracker was operated with the full CMS experiment in a comprehensive test, in the presence of the 3.8 T magnetic field produced by the CMS superconducting solenoid. Cosmic ray muons were detected in the muon chambers and used to trigger the readout of all CMS sub-detectors. About 15 million events with a muon in

S. Chatrchyan; V. Khachatryan; A. M. Sirunyan; W. Adam; B. Arnold; H. Bergauer; T. Bergauer; M. Dragicevic; M. Eichberger; J. Ero; M. Friedl; R. Fruhwirth; V. M. Ghete; J. Hammer; S. Hansel; M. Hoch; N. Hormann; J. Hrubec; M. Jeitler; G. Kasieczka; K. Kastner; M. Krammer; D. Liko; I. M. de Abril; I. Mikulec; F. Mittermayr; B. Neuherz; M. Oberegger; M. Padrta; M. Pernicka; H. Rohringer; S. Schmid; R. Schofbeck; T. Schreiner; R. Stark; H. Steininger; J. Strauss; A. Taurok; F. Teischinger; T. Themel; D. Uhl; P. Wagner; W. Waltenberger; G. Walzel; E. Widl; C. E. Wulz; V. Chekhovsky; O. Dvornikov; I. Emeliantchik; A. Litomin; V. Makarenko; I. Marfin; V. Mossolov; N. Shumeiko; A. Solin; R. Stefanovitch; J. S. Gonzalez; A. Tikhonov; A. Fedorov; A. Karneyeu; M. Korzhik; V. Panov; R. Zuyeuski; P. Kuchinsky; W. Beaumont; L. Benucci; M. Cardaci; E. A. De Wolf; E. Delmeire; D. Druzhkin; M. Hashemi; X. Janssen; T. Maes; L. Mucibello; S. Ochesanu; R. Rougny; M. Selvaggi; H. Van Haevermaet; P. Van Mechelen; N. Van Remortel; V. Adler; S. Beauceron; S. Blyweert; J. DHondt; S. De Weirdt; O. Devroede; J. Heyninck; A. Kalogeropoulos; J. Maes; M. Maes; M. U. Mozer; S. Tavernier; W. Van Doninck; P. Van Mulders; I. Villella; O. Bouhali; E. C. Chabert; O. Charaf; B. Clerbaux; G. De Lentdecker; V. Dero; S. Elgammal; A. P. R. Gay; G. H. Hammad; P. E. Marage; S. Rugovac; C. V. Velde; P. Vanlaer; J. Wickens; M. Grunewald; B. Klein; A. Marinov; D. Ryckbosch; F. Thyssen; M. Tytgat; L. Vanelderen; P. Verwilligen; S. Basegmez; G. Bruno; J. Caudron; C. Delaere; P. Demin; D. Favart; A. Giammanco; G. Gregoire; V. Lemaitre; O. Militaru; S. Ovyn; K. Piotrzkowski; L. Quertenmont; N. Schul; N. Beliy; E. Daubie; G. A. Alves; M. E. Pol; M. H. G. Souza; W. Carvalho; D. D. Damiao; C. D. Martins; S. F. De Souza; L. Mundim; V. Oguri; A. Santoro; S. M. S. Do Amaral; A. Sznajder; Trfp Tomei; M. A. F. Dias; E. M. Gregores; S. F. Novaes; K. Abadjiev; T. Anguelov; J. Damgov; N. Darmenov; L. Dimitrov; V. Genchev; P. Iaydjiev; S. Piperov; S. Stoykova; G. Sultanov; R. Trayanov; I. Vankov; A. Dimitrov; M. Dyulendarova; V. Kozhuharov; L. Litov; E. Marinova; M. Mateev; B. Pavlov; P. Petkov; Z. Toteva; G. M. Chen; H. S. Chen; W. Guan; C. H. Jiang; D. Liang; B. Liu; X. Meng; J. Tao; J. Wang; Z. Wang; Z. Xue; Z. Zhang; Y. Ban; J. Cai; Y. Ge; S. Guo; Z. Hu; Y. Mao; S. J. Qian; H. Teng; B. Zhu; C. Avila; M. B. Ruiz; C. A. C. Montoya; A. Gomez; B. G. Moreno; A. A. O. Rios; A. F. O. Oliveros; D. R. Romero; J. C. Sanabria; N. Godinovic; K. Lelas; R. Plestina; D. Polic; I. Puljak; Z. Antunovic; M. Dzelalija; V. Brigljevic; S. Duric; K. Kadija; S. Morovic; R. Fereos; M. Galanti; J. Mousa; A. Papadakis; F. Ptochos; P. A. Razis; D. Tsiakkouri; Z. Zinonos; A. Hektor; M. Kadastik; K. Kannike; M. Muntel; M. Raidal; L. Rebane; E. Anttila; S. Czellar; J. Harkonen; A. Heikkinen; V. Karimaki; R. Kinnunen; J. Klem; M. J. Kortelainen; T. Lampen; K. Lassila-Perini; S. Lehti; T. Linden; P. Luukka; T. Maenpaa; J. Nysten; E. Tuominen; J. Tuominiemi; D. Ungaro; L. Wendland; K. Banzuzi; A. Korpela; T. Tuuva; P. Nedelec; D. Sillou; M. Besancon; R. Chipaux; M. Dejardin; D. Denegri; J. Descamps; B. Fabbro; J. L. Faure; F. Ferri; S. Ganjour; F. X. Gentit; A. Givernaud; P. Gras; G. H. de Monchenault; P. Jarry; M. C. Lemaire; E. Locci; J. Malcles; M. Marionneau; L. Millischer; J. Rander; A. Rosowsky; D. Rousseau; M. Titov; P. Verrecchia; S. Baffioni; L. Bianchini; M. Bluj; P. Busson; C. Charlot; L. Dobrzynski; R. G. de Cassagnac; M. Haguenauer; P. Mine; P. Paganini; Y. Sirois; C. Thiebaux; A. Zabi; J. L. Agram; A. Besson; D. Bloch; D. Bodin; J. M. Brom; E. Conte; F. Drouhin; J. C. Fontaine; D. Gele; U. Goerlach; L. Gross; P. Juillot; A. C. Le Bihan; Y. Patois; J. Speck; P. Van Hove; C. Baty; M. Bedjidian; J. Blaha; G. Boudoul; H. Brun; N. Chanon; R. Chierici; D. Contardo; P. Depasse; T. Dupasquier; H. El Mamouni; F. Fassi; J. Fay; S. Gascon; B. Ille; T. Kurca; T. Le Grand; M. Lethuillier; N. Lumb; L. Mirabito; S. Perries; M. V. Donckt; P. Verdier; N. Djaoshvili; N. Roinishvili; V. Roinishvili; N. Amaglobeli; R. Adolphi; G. Anagnostou; R. Brauer; W. Braunschweig; M. Edelhoff; H. Esser; L. Feld; W. Karpinski; A. Khomich; K. Klein; N. Mohr; A. Ostaptchouk; D. Pandoulas; G. Pierschel; F. Raupach; S. Schael; A. S. von Dratzig; G. Schwering; D. Sprenger; M. Thomas; M. Weber; B. Wittmer; M. Wlochal; O. Actis; G. Altenhofer; W. Bender; P. Biallass; M. Erdmann; G. Fetchenhauer; J. Frangenheim; T. Hebbeker; G. Hilgers; A. Hinzmann; K. Hoepfner; C. Hof; M. Kirsch; T. Klimkovich; P. Kreuzer; D. Lanske; M. Merschmeyer; A. Meyer; B. Philipps; H. Pieta; H. Reithler; S. A. Schmitz; L. Sonnenschein; M. Sowa; J. Steggemann; H. Szczesny; D. Teyssier; C. Zeidler; M. Bontenackels; M. Davids; M. Duda; G. Flugge; H. Geenen; M. Giffels; W. H. Ahmad; T. Hermanns; D. Heydhausen; S. Kalinin

2010-01-01

398

GRANAT\\/WATCH catalogue of cosmic gamma-ray bursts: December 1989 to September 1994  

Microsoft Academic Search

We present the catalogue of gamma-ray bursts (GRB) observed with the WATCH all-sky monitor on board the GRANAT satellite during the period December 1989 to September 1994. The cosmic origin of 95 bursts comprising the catalogue is confirmed either by their localization with WATCH or by their detection with other GRB experiments. For each burst its time history and information

S. Y. Sazonov; R. A. Sunyaev; Oleg V. Terekhov; Niels Lund; Soren Brandt; A. J. Castro-Tirado

1998-01-01

399

The MARIACHI Project: Mixed Apparatus for Radio Investigation of Atmospheric Cosmic Rays of High Ionization  

Microsoft Academic Search

Extreme Energy Cosmic Rays are nuclei that have been accelerated to kinetic energies in excess of 1020 eV. Where do they come from? How are they produced? Are they survivors of the early universe? Are they remnants of supernovas? MARIACHI, a unique collaboration between scientists, physics teachers and students, is an innovative technique that allows us to detect and study

M. D. Inglis; H. Takai; R. Warasia; J. Sundermier

2005-01-01

400

Abundance of low energy (50-150 MeV) antiprotons in cosmic rays  

NASA Astrophysics Data System (ADS)

The authors present the progress of their nuclear emulsion experiment to determine the abundance of low energy antiprotons in cosmic rays. They have not detected any so far and obtain an upper limit of p/p ? 4×10-4 in the energy range 50 - 150 MeV.

Apparao, K. M. V.; Biswas, S.; Durgaprasad, N.; Stephens, S. A.

1985-08-01

401

Pickup Ions and Cosmic Rays from Dust in the Heliosphere  

NASA Astrophysics Data System (ADS)

The combination of recent observational and theoretical work has completed the catalog of the sources of heliospheric Pickup Ions (PUIs). These PUIs are the seed population for Anomalous Cosmic Rays (ACRs), which are accelerated to high energies at or beyond the Termination Shock (TS). For elements with high First Ionization Potentials (high-FIP atoms: e.g., H, He, Ne, etc.), the dominant source of PUIs and ACRs is from neutral atoms that drift into the heliosphere from the Local Interstellar Medium (LISM) and, prior to ionization, are influenced primarily by solar gravitation and radiation pressure (for H). After ionization, these interstellar ions are pickup up by the solar wind, swept out, and are either accelerated near the TS or beyond it. Elements with low first ionization potentials (low-FIP atoms: e.g., C, Si, Mg, Fe, etc.) are also observed as PUIs by Ulysses and as ACRs by Wind and Voyager. But the low-FIP composition of this additional component reveals a very different origin. Low-FIP interstellar atoms are predominantly ionized in the LISM and therefore excluded from the heliosphere by the solar wind. Remarkably, a low-FIP component of PUIs was hypothesized by Banks (J. Geophys. Res. 76, 4341, 1971) over twenty years prior to its direct detection by Ulysses/SWICS (Geiss et al., J. Geophys. Res. 100(23), 373, 1995) The leading concept for the generation of Inner Source PUIs involves an effective recycling of solar wind on grains near the Sun, as originally suggested by Banks. Voyager and Wind also observe low-FIP ACRs, and a grain-related source appears likely and necessary. Two concepts have been proposed to explain these low-FIP ACRs: the first concept involves the acceleration of the Inner Source of PUIs, and the second involves a so-called Outer Source of PUIs generated from solar wind interaction with the large population of grains in the Kuiper Belt. We review here the observational and theoretical work over the last decade that shows how solar wind and heliospheric grains interact to produce pickup ions, and, in turn, anomalous cosmic rays. The inner and outer sources of pickup ions and anomalous cosmic rays exemplify dusty plasma interactions that are fundamental throughout the cosmos for the production of energetic particles and the formation of stellar systems.

Schwadron, N. A.; Gloeckler, G.

402

Pickup Ions and Cosmic Rays from Dust in the Heliosphere  

NASA Astrophysics Data System (ADS)

The combination of recent observational and theoretical work has completed the catalog of the sources of heliospheric Pickup Ions (PUIs). These PUIs are the seed population for Anomalous Cosmic Rays (ACRs), which are accelerated to high energies at or beyond the Termination Shock (TS). For elements with high First Ionization Potentials (high-FIP atoms: e.g., H, He, Ne, etc.), the dominant source of PUIs and ACRs is from neutral atoms that drift into the heliosphere from the Local Interstellar Medium (LISM) and, prior to ionization, are influenced primarily by solar gravitation and radiation pressure (for H). After ionization, these interstellar ions are pickup up by the solar wind, swept out, and are either accelerated near the TS or beyond it. Elements with low first ionization potentials (low-FIP atoms: e.g., C, Si, Mg, Fe, etc.) are also observed as PUIs by Ulysses and as ACRs by Wind and Voyager. But the low-FIP composition of this additional component reveals a very different origin. Low-FIP interstellar atoms are predominantly ionized in the LISM and therefore excluded from the heliosphere by the solar wind. Remarkably, a low-FIP component of PUIs was hypothesized by Banks (J. Geophys. Res. 76, 4341, 1971) over twenty years prior to its direct detection by Ulysses/SWICS (Geiss et al., J. Geophys. Res. 100(23), 373, 1995) The leading concept for the generation of Inner Source PUIs involves an effective recycling of solar wind on grains near the Sun, as originally suggested by Banks. Voyager and Wind also observe low-FIP ACRs, and a grain-related source appears likely and necessary. Two concepts have been proposed to explain these low-FIP ACRs: the first concept involves the acceleration of the Inner Source of PUIs, and the second involves a so-called Outer Source of PUIs generated from solar wind interaction with the large population of grains in the Kuiper Belt. We review here the observational and theoretical work over the last decade that shows how solar wind and heliospheric grains interact to produce pickup ions, and, in turn, anomalous cosmic rays. The inner and outer sources of pickup ions and anomalous cosmic rays exemplify dusty plasma interactions that are fundamental throughout the cosmos for the production of energetic particles and the formation of stellar systems.

Schwadron, N. A.; Gloeckler, G.

2007-06-01

403

Research in cosmic and gamma ray astrophysics: Cosmic physics portion  

Microsoft Academic Search

Research in particle astrophysics at the Space Radiation Laboratory (SRL) of the California Institute of Technology is supported under NASA Grant NAGW-1919. A three-year proposal for continuation of support was submitted a year ago and put into effect 1 October 1992. This report is the combined progress report and continuation application called for under the Federal Demonstration Project. Gamma-ray Astrophysics

Edward C. Stone; Richard A. Mewaldt; Stephen Schindler

1993-01-01

404

Photon losses in cosmic ray acceleration in active galactic nuclei  

SciTech Connect

The usual assumption of the acceleration of ultrahigh energy cosmic rays, greater than or equal to 10/sup 18/ eV in quasars, Seyfert galaxies, and other active galactic nuclei is challenged on the basis of the photon interactions with the accelerated nucleons. This is similar to the effect of the black body radiation on particles > 10/sup 20/ eV for times of the age of the universe except that the photon spectrum is harder and the energy density greater by approx. = 10/sup 13/. Hence, a single traversal, radial or circumferential, of radiation whose energy density is no greater than the emitted flux will damp an ultrahigh energy cosmic ray 10/sup 20/ eV by greater than 10/sup 4/ times its energy. Hence, it is unlikely that any reasonable configuration of acceleration can avoid disastrous photon energy loss. A different site for ultrahigh energy cosmic ray acceleration must be found.

Colgate, S.A.

1984-01-01

405

Initial conditions for radiation analysis: Solar modulation of cosmic rays  

NASA Astrophysics Data System (ADS)

Galactic and solar cosmic rays reaching Earth must first make their way through the turbulent and highly variable solar wind plasma. In a process termed "solar modulation," the intensity and energy spectrum of Galactic cosmic rays is altered by the solar wind. Important mechanisms of modulation include scattering by magnetic turbulence, adiabatic energy loss in the expanding wind, and drift in the inhomogeneous large-scale field. Theoretical tools for modeling cosmic ray transport in the solar wind include Parker's modulation equation and, for solar particle transport, the Boltzmann equation. This talk will summarize the factors governing particle transport and modulation and will present examples of quantitative modeling of these key processes. Supported by NSF grant ATM-0000315.

Bieber, J. W.

406

Cosmic-ray transport in the heliosphere: A global perspective  

NASA Astrophysics Data System (ADS)

Earth is shielded from the hazardous galactic radiation in the form or cosmic ray ions by the outwardly flow of the solar wind plasma and by the geomagnetic field. Understanding the effects of the global structure of the heliosphere on the transport of energetic charged particles remains an important challenge in space physics. The expanding bubble of the supersonic solar wind cools the populations of GeV ions that penetrate deeply into the interplanetary space. Beyond the solar wind lies the heliosheath that is believed to act as a long-term storage reservoir for the cosmic rays. The heliosheath and its magnetic field topology play an important role in modulating cosmic rays at large heliocentric distances. Understanding this role is crucial for interpreting the the puzzling Voyager spacecraft observations near the edge of the solar system.

Florinski, Vladimir

2013-02-01

407

Energy spectra and composition of primary cosmic rays  

NASA Astrophysics Data System (ADS)

New results are described on the energy spectra and relative abundances of primary cosmic ray nuclei from carbon to iron. The measurement was performed on the Spacelab-2 mission of the Space Shuttle Challenger in 1985, and extends to energies beyond 1 TeV per amu. The data indicate that the cosmic ray flux arriving near earth becomes enriched with heavier nuclei, most notably iron, as energy increases. Extrapolating to the source, with a simple leaky box model of galactic propagation with rigidity-dependent containment time, relative abundances of the elements are obtained that are quite similar to those reported at lower energy. In particular, the depletion of elements with high first ionization potential relative to the local galactic abundances, seems to persist in the cosmic ray source well up to TeV energies. A single power-law energy spectrum about E exp -2.1 provides a good description of the observed spectra of most elemental species.

Mueller, Dietrich; Swordy, Simon P.; Meyer, Peter; L'Heureux, Jacques; Grunsfeld, John M.

1991-06-01

408

A Cosmic-Ray Resolution to the Superbubble Energy Crisis  

NASA Astrophysics Data System (ADS)

Superbubbles (SBs) are among the greatest injectors of energy into the Galaxy, and have been proposed to be the acceleration site of Galactic cosmic rays. They are thought to be powered by the fast stellar winds and powerful supernova explosions of massive stars in dense stellar clusters and associations. Observations of the SB ``DEM L192'' in the neighboring Large Magellanic Cloud (LMC) show that it contains only about one-third the energy injected by its constituent stars via fast stellar winds and supernovae. It is not yet understood where the excess energy is going-thus, the so-called energy-crisis. We show here that it is very likely that a significant fraction of the unaccounted for energy is being taken up in accelerating cosmic rays, thus bolstering the argument for the SB origin of cosmic rays.

Butt, Yousaf M.; Bykov, Andrei M.

2008-04-01

409

Expansion Plans for the Telescope Array cosmic ray observatory  

NASA Astrophysics Data System (ADS)

The Telescope Array (TA) cosmic ray observatory has now been operational for nearly three years and will be the largest cosmic ray observatory in the Northern Hemisphere for the foreseeable future. Two major expansions are currently being planned. The first expansion, TA Low Energy Extension, will increase the dynamic range of TA in order to enable seamless observation from 10^16.5 to 10^20 eV in primary cosmic ray energy. The second expansion, TA Next, will dramatically increase the aperture of TA above 10^19.8 eV with the aim of searching for anisotropies inarrival directions for these highest energy events. Current efforts and future plans will be discussed.

Stokes, Benjamin

2011-04-01

410

Charge sign solar modulatio nof cosmic ray positrons and negatrons  

NASA Astrophysics Data System (ADS)

On August 25, 2000 (from Lynn Lake, Manitoba) we conducted a balloon flight of the LEE/AESOP payload to measure the spectrum of cosmic ray electrons (resolved into negatrons and positrons) from 500 MeV to 3 GeV. Analysis of the data from that flight reveals a significant decrease in the cosmic ray positron abundance from a level that remained relatively stable throughout the decade of the 1990's. Errors on the new determination are comparatively large due to the low particle fluxes at solar maximum. Nevertheless, the magnitude of the effect is consistent with predictions based on the assumption that cosmic ray modulation effects with 22-year periodicity are related simply and directly to charge sign and large-scale structure of the heliospheric magnetic field.

Clem, J. M.; Evenson, P.

2001-08-01

411

Opportunities in cosmic-ray physics and astrophysics  

NASA Astrophysics Data System (ADS)

The Board on Physics and Astronomy of the National Research Council established the Committee on Cosmic-Ray Physics to prepare a review of the field that addresses both experimental and theoretical aspects of the origin of cosmic radiation from outside the heliosphere. The following recommendations are made: NASA should provide the opportunity to measure cosmic-ray electrons, positrons, ultraheavy nuclei, isotopes, and antiparticles in space; NASA, the National Science Foundation (NSF), and the Department of Energy (DOE) should facilitate direct and indirect measurement of the elemental composition to as high an energy as possible, for which the support of long-duration ballooning and hybrid ground arrays will be needed; NSF and DOE should support the new Fly's Eye and provide for U.S. participation in the big projects on the horizon, which include giant arrays, ground-based gamma-ray astronomy, and neutrino telescopes; and NASA, NSF, and DOE should support a strong program of relevant theoretical investigations.

1995-09-01

412

The Cosmic Diffuse Gamma-Ray Background measured with COMPTEL  

NASA Astrophysics Data System (ADS)

One of the principal scientific goals of the Compton telescope COMPTEL onboard the Compton Gamma-Ray Observatory was to study the cosmic diffuse gamma-ray background (hereafter CDG). COMPTEL, which measures gamma-rays from 0.8-30 MeV, is uniquely suited to study the CDG because of its wide field-of-view (~ 1 sr), long exposure time, and capability of correcting for short- and long-lived instrumental backgrounds. We present a summary of the major COMPTEL results on the CDG. The CDG spectrum merges smoothly with the spectra at higher and lower energies, and is consistent with a transition from a softer to a harder component around a few MeV. No evidence for the MeV-bump, an excess of emission at MeV energies detected by previous experiments, could be found. Comparison of the CDG intensity from various regions of the sky allows us to place limits on the large-scale anisotropy of the CDG in selected energy bands. Upper limits on the relative deviations from isotropy consistent with the data at the 95% confidence limit range from about 24% to about 45% on scales of a few steradian. The COMPTEL results on the CDG are put in perspective with recent results at lower and higher energies, and the implications of these measurements for the origin of the CDG are discussed.

Weidenspointner, G.; Varendorff, M.; Diehl, R.; Lichti, G. G.; Schönfelder, V.; Kappadath, S. C.; Ryan, J.; Bloemen, H.; Hermsen, W.; Bennett, K.

413

Cosmic rays and stochastic magnetic reconnection in the heliotail  

NASA Astrophysics Data System (ADS)

Galactic cosmic rays are believed to be generated by diffusive shock acceleration processes in Supernova Remnants, and the arrival direction is likely determined by the distribution of their sources throughout the Galaxy, in particular by the nearest and youngest ones. Transport to Earth through the interstellar medium is expected to affect the cosmic ray properties as well. However, the observed anisotropy of TeV cosmic rays and its energy dependence cannot be explained with diffusion models of particle propagation in the Galaxy. Within a distance of a few parsec, diffusion regime is not valid and particles with energy below about 100 TeV must be influenced by the heliosphere and its elongated tail. The observation of a highly significant localized excess region of cosmic rays from the apparent direction of the downstream interstellar flow at 1-10 TeV energies might provide the first experimental evidence that the heliotail can affect the transport of energetic particles. In particular, TeV cosmic rays propagating through the heliotail interact with the 100-300 AU wide magnetic field polarity domains generated by the 11 yr cycles. Since the strength of non-linear convective processes is expected to be larger than viscous damping, the plasma in the heliotail is turbulent. Where magnetic field domains converge on each other due to solar wind gradient, stochastic magnetic reconnection likely occurs. Such processes may be efficient enough to re-accelerate a fraction of TeV particles as long as scattering processes are not strong. Therefore, the fractional excess of TeV cosmic rays from the narrow region toward the heliotail direction traces sightlines with the lowest smearing scattering effects, that can also explain the observation of a harder than average energy spectrum.

Desiati, P.; Lazarian, A.

2012-06-01

414

Cosmic rays, supernova, and the origin of ultrahigh energy particles  

SciTech Connect

The acceleration of ultrahigh energy cosmic rays, greater than or equal to10/sup 15 -20/ eV, is still an unsolved problem in high-energy astrophysics. The now classical mechanism of stochastic acceleration of cosmic rays in a strong shock in the interstellar or intergalactic medium is limited in time and dimension for all likely acceleration sites, particularly for the highest energies. Acceleration of cosmic rays across a plasma shock of velocity, ..beta../sub s/ (..beta../sub s/ = v/sub shock//c), requires 1/..beta../sub s/ number of crossings and therefore (1/..beta../sub s/)/sup 2/ number of scatterings for doubling the energy of a particle. This requires a space of the order of 1/..beta../sub s/ x the scattering length, or a multiple of the Larmor radius and hence, the space requirements to cosmic ray acceleration are very many Larmor orbits in dimension, as well as times that are larger by (1/..beta../sub s/)/sup 2/ x t/sub Larmor/. The acceleration of cosmic rays by the shock in the envelope of a Type 1 supernova is reviewed, and the interaction of the accelerated matter with the nearby ISM is considered. The spectrum of relativistic ejected matter is preferentially trapped in the ISM. Further acceleration of each energy group should take place in both the near relativistic shock wave and the compression by the following matter. The possible acceleration of ultrahigh energy cosmic rays in the accretion disk of a near-stationery magnetic neutron star such as Cyg-X3 is another strong possibility. Here the diffusion of magnetic flux radially outwards opposite to the viscous diffusion of mass radially inwards is considered as a likely topology for a unipolar generator acceleration of ultrahigh energy particles.

Colgate, S.A.

1985-01-01

415

Detection of gamma rays from a starburst galaxy.  

PubMed

Starburst galaxies exhibit in their central regions a highly increased rate of supernovae, the remnants of which are thought to accelerate energetic cosmic rays up to energies of approximately 10(15) electron volts. We report the detection of gamma rays--tracers of such cosmic rays--from the starburst galaxy NGC 253 using the High Energy Stereoscopic System (H.E.S.S.) array of imaging atmospheric Cherenkov telescopes. The gamma-ray flux above 220 billion electron volts is F = (5.5 +/- 1.0(stat) +/- 2.8(sys)) x 10(-13) cm(-2) s(-1), implying a cosmic-ray density about three orders of magnitude larger than that in the center of the Milky Way. The fraction of cosmic-ray energy channeled into gamma rays in this starburst environment is five times as large as that in our Galaxy. PMID:19779150

Acero, F; Aharonian, F; Akhperjanian, A G; Anton, G; Barres de Almeida, U; Bazer-Bachi, A R; Becherini, Y; Behera, B; Bernlöhr, K; Bochow, A; Boisson, C; Bolmont, J; Borrel, V; Brucker, J; Brun, F; Brun, P; Bühler, R; Bulik, T; Büsching, I; Boutelier, T; Chadwick, P M; Charbonnier, A; Chaves, R C G; Cheesebrough, A; Chounet, L-M; Clapson, A C; Coignet, G; Dalton, M; Daniel, M K; Davids, I D; Degrange, B; Deil, C; Dickinson, H J; Djannati-Ataï, A; Domainko, W; Drury, L O'C; Dubois, F; Dubus, G; Dyks, J; Dyrda, M; Egberts, K; Emmanoulopoulos, D; Espigat, P; Farnier, C; Fegan, S; Feinstein, F; Fiasson, A; Förster, A; Fontaine, G; Füssling, M; Gabici, S; Gallant, Y A; Gérard, L; Gerbig, D; Giebels, B; Glicenstein, J F; Glück, B; Goret, P; Göring, D; Hauser, D; Hauser, M; Heinz, S; Heinzelmann, G; Henri, G; Hermann, G; Hinton, J A; Hoffmann, A; Hofmann, W; Hofverberg, P; Hoppe, S; Horns, D; Jacholkowska, A; de Jager, O C; Jahn, C; Jung, I; Katarzy?ski, K; Katz, U; Kaufmann, S; Kerschhaggl, M; Khangulyan, D; Khélifi, B; Keogh, D; Klochkov, D; Klu?niak, W; Kneiske, T; Komin, Nu; Kosack, K; Kossakowski, R; Lamanna, G; Lenain, J-P; Lohse, T; Marandon, V; Martineau-Huynh, O; Marcowith, A; Masbou, J; Maurin, D; McComb, T J L; Medina, M C; Méhault, J; Moderski, R; Moulin, E; Naumann-Godo, M; de Naurois, M; Nedbal, D; Nekrassov, D; Nicholas, B; Niemiec, J; Nolan, S J; Ohm, S; Olive, J-F; de Oña Wilhelmi, E; Orford, K J; Ostrowski, M; Panter, M; Paz Arribas, M; Pedaletti, G; Pelletier, G; Petrucci, P-O; Pita, S; Pühlhofer, G; Punch, M; Quirrenbach, A; Raubenheimer, B C; Raue, M; Rayner, S M; Reimer, O; Renaud, M; Rieger, F; Ripken, J; Rob, L; Rosier-Lees, S; Rowell, G; Rudak, B; Rulten, C B; Ruppel, J; Sahakian, V; Santangelo, A; Schlickeiser, R; Schöck, F M; Schwanke, U; Schwarzburg, S; Schwemmer, S; Shalchi, A; Sikora, M; Skilton, J L; Sol, H; Stawarz, ?; Steenkamp, R; Stegmann, C; Stinzing, F; Superina, G; Szostek, A; Tam, P H; Tavernet, J-P; Terrier, R; Tibolla, O; Tluczykont, M; van Eldik, C; Vasileiadis, G; Venter, C; Venter, L; Vialle, J P; Vincent, P; Vivier, M; Völk, H J; Volpe, F; Wagner, S J; Ward, M; Zdziarski, A A; Zech, A

2009-09-24

416

Wolf-Rayet Stars and Cosmic Gamma-ray Bursts  

Microsoft Academic Search

The observational properties of cosmic gamma-ray bursts and of Wolf-Rayet (WR) stars and their CO cores at the end of their evolution are analyzed. WR stars do not have hydrogen envelopes, facilitating the transformation of the energy of collapse into observable gamma rays. Of the ≈90 well-localized gamma-ray bursts, 21 have optical identifications, of which 16 have measured redshifts (z=0.4

K. A. Postnov; A. M. Cherepashchuk

2001-01-01

417

Hybrid Cosmic Ray Detector at Pico de Orizaba  

NASA Astrophysics Data System (ADS)

In this work we present the design features and simulation of the hybrid detector under construction at 4300 m.a.s.l. equivalent to 620 g /cm2 .The goal of this observatory is to study the mass composition of the cosmic rays in the energy range of 1015 - 1018 eV. The observation technique include particle counting and fluorescence detection in order to improve the Energy and Xmax determination. This approach allow us to contribute in the knowledge of the knee composition, corresponding to medium to heavy nuclei. Introduction One of the open problems of the high energy cosmic ray is the composition of the primary particles with energies from 1 × 1015 to 1 × 1018 . In order to contribute to solve this issue, we have design and hybrid detector to be located in the Pico de Orizaba and Sierra la Negra Volcano es. One of the advantages of the site is the altitude, 4200 m.a.s.l, which may help us to observe the extended air showers nearby their maximum development, improving the determination of the parameters of the primary particle. The optical properties of the site have been studied by several years, showing stability and darkness to declare it as a good optical astronomical site. So, we thought that the installation of an fluorescence telescope, should complement the ground array and improve the overall performance of this observatory. In the other side, the implementation of the hybrid technique, based in montecarlo simulations, may allow us to separate the light and the heavy primary components. Based in simulations, we expect good quality measurement of the number of secondary particles due to the proximity of the array to the level of maximum development of the EAS Xmax .

Cotzomi, J.; Martinez, O.; Medina, M.; Moreno, E.; Salazar, H.; Ponce, G.; Pérez, L.; Villaseñor, L.; Khrenov, B.; Garipov, G.

2003-07-01

418

Building up the spectrum of cosmic rays in star-forming regions  

NASA Astrophysics Data System (ADS)

The common approach to compute the cosmic ray distribution in a starburst galaxy or region is equivalent to assuming that at any point within that environment, there is an accelerator inputting cosmic rays at a reduced rate. This rate should be compatible with the overall volume-average injection, given by the total number of accelerators that were active during the starburst age. These assumptions seem reasonable, especially under the supposition of a homogeneous and isotropic distribution of accelerators. However, in this approach the temporal evolution of the superposed spectrum is not explicitly derived; rather, it is essentially assumed ab initio. Here, we test the validity of this approach by following the temporal evolution and spatial distribution of the superposed cosmic ray spectrum and compare our results with those from theoretical models that treat the starburst region as a single source. In the calorimetric limit (with no cosmic ray advection), homogeneity is reached (typically within 20 per cent) across most of the starburst region. However, values of centre-to-edge intensity ratios can amount to a factor of several. Differences between the common homogeneous assumption for the cosmic ray distribution and our models are larger in the case of two-zone geometries, such as a central nucleus with a surrounding disc. We have also found that the decay of the cosmic ray density following the duration of the starburst process is slow, and even approximately 1 Myr after the burst ends (for a gas density of 35 cm-3) it may still be within an order of magnitude of its peak value. Based on our simulations, it seems that the detection of a relatively hard spectrum up to the highest gamma-ray energies from nearby starburst galaxies favours a relatively small diffusion coefficient (i.e. long diffusion time) in the region where most of the emission originates.

Torres, Diego F.; Cillis, Analía.; Lacki, Brian; Rephaeli, Yoel

2012-06-01

419

Time Structure of Gamma-Ray Signals Generated in Line-of-sight Interactions of Cosmic Rays from Distant Blazars  

NASA Astrophysics Data System (ADS)

Blazars are expected to produce both gamma rays and cosmic rays. Therefore, observed high-energy gamma rays from distant blazars may contain a significant contribution from secondary gamma rays produced along the line of sight by the interactions of cosmic-ray protons with background photons. Unlike the standard models of blazars that consider only the primary photons emitted at the source, models that include the cosmic-ray contribution predict that even ~10 TeV photons should be detectable from distant objects with redshifts as high as z >= 0.1. Secondary photons contribute to signals of point sources only if the intergalactic magnetic fields are very small, B <~ 10-14 G, and their detection can be used to set upper bounds on magnetic fields along the line of sight. Secondary gamma rays have distinct spectral and temporal features. We explore the temporal properties of such signals using a semi-analytical formalism and detailed numerical simulations, which account for all the relevant processes, including magnetic deflections. In particular, we elucidate the interplay of time delays coming from the proton deflections and from the electromagnetic cascade, and we find that, at multi-TeV energies, secondary gamma rays can show variability on timescales of years for B ~ 10-15 G.

Prosekin, Anton; Essey, Warren; Kusenko, Alexander; Aharonian, Felix

2012-10-01

420

Cosmic ray energy spectrum from measurements of air showers  

NASA Astrophysics Data System (ADS)

This review focuses on high-energy cosmic rays in the PeV energy range and above. Of particular interest is the knee of the spectrum around 3 PeV and the transition from cosmic rays of Galactic origin to particles from extra-galactic sources. Our goal is to establish a baseline spectrum from 1014 to 1020 eV by combining the results of many measurements at different energies. In combination with measurements of the nuclear composition of the primaries, the shape of the energy spectrum places constraints on the number and spectra of sources that may contribute to the observed spectrum.

Gaisser, T. K.; Stanev, T.; Tilav, S.

2013-04-01