WorldWideScience

Sample records for cosmic radiation field

  1. Cosmic Radiation Fields: Sources in the early Universe

    Science.gov (United States)

    Raue, Martin; Kneiske, Tanja; Horns, Dieter; Elsaesser, Dominik; Hauschildt, Peter

    The workshop "Cosmic Radiation Fields - Sources in the Early Universe" (CRF 2010) focuses on the connection between the extragalactic infrared background and sources in the early universe, in particular stars powered by dark matter burning (Dark Stars; DS). The workshop covers the following topics: the cosmic infrared background, formation of early stars, dark stars, effect of dark matter in the early universe, dark matter halos, primordial star formation rate, and reionization. Further information can be found on the conference webpage: http://www.desy.de/crf2010/. Organizing committee: Tanja Kneiske, Martin Raue, Dominik Elsaesser, Alexander Gewering-Peine, Peter Hausschildt, Dieter Horns, and Andreas Maurer.

  2. CONCORD: comparison of cosmic radiation detectors in the radiation field at aviation altitudes

    OpenAIRE

    Meier Matthias M.; Trompier François; Ambrozova Iva; Kubancak Jan; Matthiä Daniel; Ploc Ondrej; Santen Nicole; Wirtz Michael

    2016-01-01

    Space weather can strongly affect the complex radiation field at aviation altitudes. The assessment of the corresponding radiation exposure of aircrew and passengers has been a challenging task as well as a legal obligation in the European Union for many years. The response of several radiation measuring instruments operated by different European research groups during joint measuring flights was investigated in the framework of the CONCORD (COmparisoN of COsmic Radiation Detectors) campaign ...

  3. CONCORD: comparison of cosmic radiation detectors in the radiation field at aviation altitudes

    Directory of Open Access Journals (Sweden)

    Meier Matthias M.

    2016-01-01

    Full Text Available Space weather can strongly affect the complex radiation field at aviation altitudes. The assessment of the corresponding radiation exposure of aircrew and passengers has been a challenging task as well as a legal obligation in the European Union for many years. The response of several radiation measuring instruments operated by different European research groups during joint measuring flights was investigated in the framework of the CONCORD (COmparisoN of COsmic Radiation Detectors campaign in the radiation field at aviation altitudes. This cooperation offered the opportunity to measure under the same space weather conditions and contributed to an independent quality control among the participating groups. The CONCORD flight campaign was performed with the twin-jet research aircraft Dassault Falcon 20E operated by the flight facility Oberpfaffenhofen of the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt, DLR. Dose rates were measured at four positions in the atmosphere in European airspace for about one hour at each position in order to obtain acceptable counting statistics. The analysis of the space weather situation during the measuring flights demonstrates that short-term solar activity did not affect the results which show a very good agreement between the readings of the instruments of the different institutes.

  4. CONCORD: comparison of cosmic radiation detectors in the radiation field at aviation altitudes

    Science.gov (United States)

    Meier, Matthias M.; Trompier, François; Ambrozova, Iva; Kubancak, Jan; Matthiä, Daniel; Ploc, Ondrej; Santen, Nicole; Wirtz, Michael

    2016-05-01

    Space weather can strongly affect the complex radiation field at aviation altitudes. The assessment of the corresponding radiation exposure of aircrew and passengers has been a challenging task as well as a legal obligation in the European Union for many years. The response of several radiation measuring instruments operated by different European research groups during joint measuring flights was investigated in the framework of the CONCORD (COmparisoN of COsmic Radiation Detectors) campaign in the radiation field at aviation altitudes. This cooperation offered the opportunity to measure under the same space weather conditions and contributed to an independent quality control among the participating groups. The CONCORD flight campaign was performed with the twin-jet research aircraft Dassault Falcon 20E operated by the flight facility Oberpfaffenhofen of the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt, DLR). Dose rates were measured at four positions in the atmosphere in European airspace for about one hour at each position in order to obtain acceptable counting statistics. The analysis of the space weather situation during the measuring flights demonstrates that short-term solar activity did not affect the results which show a very good agreement between the readings of the instruments of the different institutes.

  5. Isotope selective photodissociation of N-2 by the interstellar radiation field and cosmic rays

    OpenAIRE

    Heays, Alan N.; Visser, Ruud; Gredel, Roland; Ubachs, Wim; Lewis, Brenton R.; Gibson, Stephen T.; van Dishoeck, Ewine F.

    2014-01-01

    Photodissociation of 14N2 and 14N15N occurs in interstellar clouds, circumstellar envelopes, protoplanetary discs, and other environments due to UV radiation from stellar sources and the presence of cosmic rays. This source of N atoms initiates the formation of complex N-bearing species and influences their isotopic composition. To study the photodissociation rates of 14N15N by UV continuum radiation and both isotopologues in a field of cosmic ray induced photons. To determine the effect of t...

  6. Cosmic radiation and magnetic fields: Exposure assessment and health outcomes among airline flight crews

    Science.gov (United States)

    Nicholas, Joyce Shealy

    Airline flight crews are chronically exposed to cosmic radiation and to magnetic fields generated by the aircraft's electrical system. Potential disease risks have been identified in health studies among commercial flight crews outside of the United States and among military pilots within the United States. The objectives of this study were (1) to quantify exposure to both cosmic radiation and magnetic fields onboard aircraft, (2) to develop a methodology for estimating career cosmic radiation doses to individual crew members, and (3) to compare mortality among United States commercial pilots and navigators with that of all occupational groups. Cosmic radiation equivalent doses to bone marrow and skeletal tissue were calculated on a flight-by-flight basis. Flight-by-flight calculations were used to develop an estimation methodology for cumulative (career) cosmic radiation doses. Magnetic fields were measured directly onboard aircraft during flight. Health outcomes among United States commercial pilots and navigators were investigated using proportional mortality ratios, proportional cancer mortality ratios, and mortality odds ratios. Based on the sample used in this study, the cosmic radiation equivalent dose to bone marrow and skeletal tissue associated with air travel ranges from 30 to 570 microsieverts per 100 flight hours (not including ground time) depending on altitude, latitude, phase of solar cycle, and flight duration. Magnetic field exposure appears to be characterized by frequencies between 100 and 800 hertz and varies in strength depending on stages of flight, location within the aircraft, and aircraft type. Based on limited measurements, maximum field strengths may increase from 0.6 microtesla in economy class to 1.2 microtesla in first class, suggesting that cockpit exposures may be higher. Potential synergistic effects of cosmic radiation and magnetic fields may be associated with certain cancers found in excess among flight crews, in particular

  7. Isotope selective photodissociation of N2 by the interstellar radiation field and cosmic rays

    CERN Document Server

    Heays, Alan N; Gredel, Roland; Ubachs, Wim; Lewis, Brenton R; Gibson, Stephen T; van Dishoeck, Ewine F

    2014-01-01

    Photodissociation of 14N2 and 14N15N occurs in interstellar clouds, circumstellar envelopes, protoplanetary discs, and other environments due to UV radiation from stellar sources and the presence of cosmic rays. This source of N atoms initiates the formation of complex N-bearing species and influences their isotopic composition. To study the photodissociation rates of 14N15N by UV continuum radiation and both isotopologues in a field of cosmic ray induced photons. To determine the effect of these on the isotopic composition of more complex molecules. High-resolution photodissociation cross sections of N2 are used from an accurate and comprehensive quantum- mechanical model of the molecule based on laboratory experiments. A similarly high-resolution spectrum of H2 emission following interactions with cosmic rays has been constructed. The spectroscopic data are used to calculate dissociation rates which are input into isotopically differentiated chemical models, describing an interstellar cloud and a protoplane...

  8. Characterization of the Cosmic Radiation Field at Flight Altitudes and Estimation of Aircrew Exposure

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Jong Ho

    2004-02-15

    Cosmic radiation field at flight altitudes was simulated using the FLUKA Monte Carlo transport code and the spectra of secondary particles were obtained from the simulation. The obtained particle spectra were converted into effective dose rates by means of appropriate sets of conversion coefficients. The result shows that higher dose rates are observed at the higher altitude than the lower, at the higher latitude than the lower, and at the solar minimum than the maximum. Also it is confirmed that CARI-6 used in the estimation of aircrew exposure along specific flights provides approximately the same doses as the results of FLUKA calculations. Accordingly, the route doses to the personnels on board due to cosmic radiation were calculated for Korean-based commercial international airline routes using CARI-6. Annual individual doses to aircrew and the collective effective dose of passengers were estimated by applying the calculated route doses to the flight schedules of aircrew and the air travel statistics of Korea. The result shows that the annual doses to aircrew exceed the annual dose limit of public and are comparable to those of the group of workers occupationally exposed. Therefore it is necessary to consider the aircrew as the occupational exposure group. Also the annual collective dose to 11 million Korean passengers in 2001 appeared to be 136 man-Sv.

  9. Cosmic Rays and Radiative Instabilities

    CERN Document Server

    Hartquist, T W; Falle, S A E G; Pittard, J M; Van Loo, S

    2011-01-01

    In the absence of magnetic fields and cosmic rays, radiative cooling laws with a range of dependences on temperature affect the stability of interstellar gas. For about four and a half decades, astrophysicists have recognised the importance of the thermal instablity for the formation of clouds in the interstellar medium. Even in the past several years, many papers have concerned the role of the thermal instability in the production of molecular clouds. About three and a half decades ago, astrophysicists investigating radiative shocks noticed that for many cooling laws such shocks are unstable. Attempts to address the effects of cosmic rays on the stablity of radiative media that are initially uniform or that have just passed through shocks have been made. The simplest approach to such studies involves the assumption that the cosmic rays behave as a fluid. Work based on such an approach is described. Cosmic rays have no effect on the stability of initially uniform, static media with respect to isobaric perturb...

  10. Radiation from cosmic string standing waves

    Science.gov (United States)

    Olum; Blanco-Pillado

    2000-05-01

    We have simulated large-amplitude standing waves on an Abelian-Higgs cosmic string in classical lattice field theory. The radiation rate falls exponentially with wavelength, as one would expect from the field profile around a gauge string. Our results agree with those of Moore and Shellard, but not with those of Vincent, Antunes, and Hindmarsh. The radiation rate falls too rapidly to sustain a scaling solution via direct radiation of particles from string length. There is thus reason to doubt claims of strong constraints on cosmic string theories from cosmic ray observations.

  11. Small-scale primordial magnetic fields and anisotropies in the cosmic microwave background radiation

    Energy Technology Data Exchange (ETDEWEB)

    Jedamzik, Karsten [Laboratoire de Univers et Particules, UMR5299-CNRS, Université de Montpellier II, F-34095 Montpellier (France); Abel, Tom, E-mail: karsten.jedamzik@um2.fr, E-mail: tabel@slac.stanford.edu [Kavli Institute for Particle Astrophysics and Cosmology, SLAC/Stanford University, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States)

    2013-10-01

    It is shown that small-scale magnetic fields present before recombination induce baryonic density inhomogeneities of appreciable magnitude. The presence of such inhomogeneities changes the ionization history of the Universe, which in turn decreases the angular scale of the Doppler peaks and increases Silk damping by photon diffusion. This unique signature could be used to (dis)prove the existence of primordial magnetic fields of strength as small as B ≅ 10{sup −11} Gauss by cosmic microwave background observations.

  12. Analytic solutions in the dyon black hole with a cosmic string: Scalar fields, Hawking radiation and energy flux

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, H.S., E-mail: horacio.santana.vieira@hotmail.com [Departamento de Física, Universidade Federal da Paraíba, Caixa Postal 5008, CEP 58051-970, João Pessoa, PB (Brazil); Centro de Ciências, Tecnologia e Saúde, Universidade Estadual da Paraíba, CEP 58233-000, Araruna, PB (Brazil); Bezerra, V.B., E-mail: valdir@fisica.ufpb.br [Departamento de Física, Universidade Federal da Paraíba, Caixa Postal 5008, CEP 58051-970, João Pessoa, PB (Brazil); Silva, G.V., E-mail: gislainevs@hotmail.com [Departamento de Física, Universidade Federal da Paraíba, Caixa Postal 5008, CEP 58051-970, João Pessoa, PB (Brazil)

    2015-11-15

    Charged massive scalar fields are considered in the gravitational and electromagnetic field produced by a dyonic black hole with a cosmic string along its axis of symmetry. Exact solutions of both angular and radial parts of the covariant Klein–Gordon equation in this background are obtained, and are given in terms of the confluent Heun functions. The role of the presence of the cosmic string in these solutions is showed up. From the radial solution, we obtain the exact wave solutions near the exterior horizon of the black hole, and discuss the Hawking radiation spectrum and the energy flux. -- Highlights: •A cosmic string is introduced along the axis of symmetry of the dyonic black hole. •The covariant Klein–Gordon equation for a charged massive scalar field in this background is analyzed. •Both angular and radial parts are transformed to a confluent Heun equation. •The resulting Hawking radiation spectrum and the energy flux are obtained.

  13. Measurements of the high energy neutron component of cosmic radiation fields in aircraft using etched track dosemeters

    CERN Document Server

    Bartlett, D T; Tanner, R J; Steele, J D

    2001-01-01

    Measurements of the complex cosmic radiation field in aircraft at altitude are made with a passive survey meter comprising routine-use thermoluminescent detectors and etched track detectors. The energy dependence of response of the etched track detectors used to determine the neutron component has been characterized, partly, up to a neutron energy of 180 MeV. The neutron detectors are routinely calibrated in the CERN EC Ref.Field. The 15% determination level for total dose equivalent is 100 mu Sv. The evidence is that the passive survey meter provides a reliable determination of route dose. (41 refs).

  14. Electromagnetic radiation of superconducting cosmic strings

    Science.gov (United States)

    Rogozin, D. A.; Zadorozhna, L. V.

    2013-12-01

    Cosmic strings are relics of the early Universe which can be formed during the phase transitions of fields with spontaneously broken symmetry in the early Universe. Their existence finds support in modern superstrings theories, both in compactification models and in theories with extended additional dimensions. Strings can hold currents, effectively become electrically superconducting wires of astrophysical dimensions. Superconducting cosmic strings can serve as powerful sources of non-thermal radiation in wide energy range. Mechanisms of radiation are synchrotron, synchrotron self-Compton and inverse-Compton on CMB photons radiation of electrons accelerated by bow shock wave, created by magnetosphere of relativistically moving string in intergalactic medium (IGM). Expected fluxes of radiation from the shocked plasma around superconducting cosmic strings are calculated for strings with various tensions and for different cases of their location. Possibilities of strings detection by existing facilities are estimated.

  15. Hydrology and Cosmic radiation

    DEFF Research Database (Denmark)

    Andreasen, Mie

    and calibration. Yet, soil moisture measurements are traditionally provided on either point or kilometer scale from electromagnetic based sensors and satellite retrievals, respectively. Above the ground surface, the cosmic-ray neutron intensity (eV range) is inversely correlated to all hydrogen present...

  16. Cosmic magnetic fields

    CERN Document Server

    Kronberg, Philipp P

    2016-01-01

    Magnetic fields are important in the Universe and their effects contain the key to many astrophysical phenomena that are otherwise impossible to understand. This book presents an up-to-date overview of this fast-growing topic and its interconnections to plasma processes, astroparticle physics, high energy astrophysics, and cosmic evolution. The phenomenology and impact of magnetic fields are described in diverse astrophysical contexts within the Universe, from galaxies to the filaments and voids of the intergalactic medium, and out to the largest redshifts. The presentation of mathematical formulae is accessible and is designed to add insight into the broad range of topics discussed. Written for graduate students and researchers in astrophysics and related disciplines, this volume will inspire readers to devise new ways of thinking about magnetic fields in space on galaxy scales and beyond.

  17. Control of the Earth's electric field intensity through solar wind modulation of galactic cosmic radiation: Support for a proposed atmospheric electrical sun-weather mechanism

    Science.gov (United States)

    Markson, R.

    1980-01-01

    The ionospheric potential and galactic cosmic radiation, found to be inversely correlated with the solar wind velocity are examined as being germane to weather modification. Since the ionospheric potential is proportional to the fair weather electric field intensity and cosmic radiation is the dominant source of atmospheric ionization, it is concluded that the Earth's overall electric field varies in phase with atmospheric ionization and that the latter is modulated by the solar wind. A proposed mechanism, in which solar control of ionizing radiation influences atmospheric electrification and thus possibly cloud physical processes is discussed. An experimental approach to critically test the proposed mechanism through comparison of the temporal variation of the Earth's electric field with conditions in the interplanetary medium is outlined.

  18. Cosmic Tachyon Background Radiation

    CERN Document Server

    Tomaschitz, R

    1999-01-01

    The equilibrium statistical mechanics of a background radiation of superluminal particles is investigated, based on a vectorial wave equation for tachyons of the Proca type. The partition function, the spectral energy density, and the various thermodynamic variables of an ideal Bose gas of tachyons in an open Robertson-Walker cosmology are derived. The negative mass square in the wave equation changes the frequency scaling in the Rayleigh-Jeans law, and there are also significant changes in the low temperature regime as compared to the microwave background, in particular in the caloric and thermal equations of state.

  19. Cosmic rays, geomagnetic field and climate changes

    Science.gov (United States)

    Shea, M.; Smart, D.

    The possibility of a connection between cosmic radiation and climate has intrigued scientists for the past several decades. The recent studies of Friis -Christensen and Svensmark has shown an observed variation of 3-4% of the global cloud cover between 1980 and 1995 that appeared to be directly correlated with the change in galactic cosmic radiation flux over the solar cycle. However, in studies of this type, not only the solar cycle modulation of cosmic radiation must be considered, but also the changes in the cosmic radiation impinging at the top of the atmosphere as a result of the long term evolution of the geomagnetic field. We present preliminary results of an on-going study of geomagnetic cutoff rigidities over a 400-year interval. These results show (1) the change in cutoff rigidity is sufficient large so that the change in cosmic radiation flux impacting the earth is approximately equal to the relative change in flux over a solar cycle, and (2) the changes in cutoff rigidity are non- uniform over the globe with both significant increases and decreases at mid-latitude locations.

  20. An empirical approach to the measurement of the cosmic radiation field at jet aircraft altitudes

    CERN Document Server

    Green, A R; Lewis, B J; Kitching, F; McCall, M J; Desormeaux, M; Butler, A A

    2005-01-01

    Researchers at the Royal Military College of Canada have accumulated extensive dose measurements performed at jet altitudes on over 160 flights and with a wide variety of detectors including a tissue equivalent proportional counter (TEPC), a smart wide energy neutron detection instrument (SWENDI), bubble detectors, thermoluminescent detectors (TLD) and an ion chamber. The summation of the individual low and high LET results from the latter equipment compared successfully to those from the TEPC on each flight. The data from these numerous worldwide flights have been encapsulated into a program that calculates the radiation dose for any flight in the world at any period in the solar cycle. This experimentally based program, Predictive Code for AIRcrew Exposure (PCAIRE) has been designed to be used by the airline industry to meet national dosimetry requirements. In Canada, for example, such a code can be used, supported by periodic measurements. With this latter requirement in mind and a desire to decrease equip...

  1. Origin of cosmic magnetic fields

    Science.gov (United States)

    Rees, M. J.

    2006-06-01

    The first significant cosmic fields, and the seed field for galactic dynamos probably developed after the formation of the first non-linear structures. The history of star formation and the intergalactic medium is controlled, at least in part, by how and when galaxies and their precursors acquired their fields. The amplification of fields behind shocks, and the diffusivity of the magnetic flux, are crucial to the interpretation of radio sources, gamma ray burst afterglows, and other energetic cosmic phenomena. The build-up of magnetic fields is an important aspect of the overall cosmogonic process.

  2. Radiative Feedback Effects during Cosmic Reionization

    Science.gov (United States)

    Sullivan, David; Iliev, Ilian T.

    2016-10-01

    We present coupled radiation hydrodynamical simulations of the epoch of reionization, aimed at probing self-feedback on galactic scales. Unlike previous works, which assume a (quasi) homogeneous UV background, we self-consistently evolve both the radiation field and the gas to model the impact of previously unresolved processes such as spectral hardening and self-shielding. We find that the characteristic halo mass with a gas fraction half the cosmic mean, Mc (z), a quantity frequently used in semi-analytical models of galaxy formation, is significantly larger than previously assumed. While this results in an increased suppression of star formation in the early Universe, our results are consistent with the extrapolated stellar abundance matching models from Moster et al. 2013.

  3. Galactic cosmic radiation environment models

    Science.gov (United States)

    Badhwar, G. D.; O'Neill, P. M.; Troung, A. G.

    2001-02-01

    Models of the radiation environment in free space and in near earth orbits are required to estimate the radiation dose to the astronauts for Mars, Space Shuttle, and the International Space Station missions, and to estimate the rate of single event upsets and latch-ups in electronic devices. Accurate knowledge of the environment is critical for the design of optimal shielding during both the cruise phase and for a habitat on Mars or the Moon. Measurements of the energy spectra of galactic cosmic rays (GCR) have been made for nearly four decades. In the last decade, models have been constructed that can predict the energy spectra of any GCR nuclei to an accuracy of better than 25%. Fresh and more accurate measurements have been made in the last year. These measurements can lead to more accurate models. Improvements in these models can be made in determining the local interstellar spectra and in predicting the level of solar modulation. It is the coupling of the two that defines a GCR model. This paper reviews of two of the more widely used models, and a comparison of their predictions with new proton and helium data from the Alpha Magnetic Spectrometer (AMS), and spectra of beryllium to iron in the ~40 to 500 MeV/n acquired by the Advanced Composition Explorer (ACE) during the 1997-98 solar minimum. Regressions equations relating the IMP-8 helium count rate to the solar modulation deceleration parameter calculated using the Climax neutron monitor rate have been developed and may lead to improvements in the predictive capacity of the models. .

  4. Cosmic decoherence: massive fields

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Junyu [Department of Physics, California Institute of Technology,Pasadena, California 91125 (United States); School of the Gifted Young, University of Science and Technology of China,Hefei, Anhui 230026 (China); Sou, Chon-Man; Wang, Yi [Department of Physics, The Hong Kong University of Science and Technology,Clear Water Bay, Kowloon, Hong Kong (China)

    2016-10-14

    We study the decoherence of massive fields during inflation based on the Zurek’s density matrix approach. With the cubic interaction between inflaton and massive fields, the reduced density matrix for the massive fields can be calculated in the Schrödinger picture which is related to the variance of the non-Gaussian exponent in the wave functional. The decoherence rate is computed in the one-loop form from functional integration. For heavy fields with m≳O(H), quantum fluctuations will easily stay in the quantum state and decoherence is unlikely. While for light fields with mass smaller than O(H), quantum fluctuations are easily decohered within 5∼10 e-folds after Hubble crossing. Thus heavy fields can play a key role in studying problems involving inflationary quantum information.

  5. Cosmic Decoherence: Massive Fields

    CERN Document Server

    Liu, Junyu; Wang, Yi

    2016-01-01

    We study the decoherence of massive fields during inflation based on the Zurek's density matrix approach. With the cubic interaction between inflaton and massive fields, the reduced density matrix for the massive fields can be calculated in the Schr\\"odinger picture which is related to the variance of the non-Gaussian exponent in the wave functional. The decoherence rate is computed in the one-loop form from functional integration. For heavy fields with $m\\gtrsim \\mathcal{O}(H)$, quantum fluctuations will easily stay in the quantum state and decoherence is unlikely. While for light fields with mass smaller than $\\mathcal{O}(H)$, quantum fluctuations are easily decohered within $5\\sim10$ e-folds after Hubble crossing. Thus heavy fields can play a key role in studying problems involving inflationary quantum information.

  6. Electromagnetic field and cosmic censorship

    CERN Document Server

    Düztaş, Koray

    2013-01-01

    We construct a gedanken experiment in which an extremal Kerr black hole interacts with a test electromagnetic field. Using Teukolsky's solutions for electromagnetic perturbations in Kerr spacetime, and the conservation laws imposed by the energy momentum tensor of the electromagnetic field and the Killing vectors of the spacetime, we prove that this interaction cannot convert the black hole into a naked singularity, thus cosmic censorship conjecture is not violated in this case.

  7. A GPU-based Calculation Method for Near Field Effects of Cherenkov Radiation Induced by Ultra High Energy Cosmic Neutrinos

    CERN Document Server

    Hu, Chia-Yu; Chen, Pisin

    2010-01-01

    The radio approach for detecting the ultra-high energy cosmic neutrinos has become a mature field. The Cherenkov signals in radio detection are originated from the charge excess of particle showers due to Askaryan effect. The conventional way of calculating the Cherenkov pulses by making Fraunhofer approximation fails when the sizes of the elongated showers become comparable with the detection distances. We present a calculation method of Cherenkov pulses based on the finite-difference time-domain (FDTD) method, and attain a satisfying effeciency via the GPU- acceleration. Our method provides a straightforward way of the near field calculation, which would be important for ultra high energy particle showers, especailly the electromagnetic showers induced by the high energy leptons produced in the neutrino charge current interactions.

  8. Field Independent Cosmic Evolution

    Directory of Open Access Journals (Sweden)

    Nayem Sk

    2013-01-01

    Full Text Available It has been shown earlier that Noether symmetry does not admit a form of corresponding to an action in which is coupled to scalar-tensor theory of gravity or even for pure theory of gravity taking anisotropic model into account. Here, we prove that theory of gravity does not admit Noether symmetry even if it is coupled to tachyonic field and considering a gauge in addition. To handle such a theory, a general conserved current has been constructed under a condition which decouples higher-order curvature part from the field part. This condition, in principle, solves for the scale-factor independently. Thus, cosmological evolution remains independent of the form of the chosen field, whether it is a scalar or a tachyon.

  9. Cosmic radiations; A la rencontre des rayons cosmiques

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2011-09-15

    Cosmic radiations were discovered one century ago, they were detected indirectly by their positive effect on the conductivity of the air through the ionization of atoms and molecules composing the air. The first measurement made on balloons showed that the ionization was increasing with altitude which discredited the idea that the radiations were coming from the earth itself. Other measurement campaigns showed that the cosmic radiations were very low at the equator which supported the idea that cosmic radiations were made up of charged particles that are deflected by the earth magnetic field. During the forties and the fifties the study of cosmic radiations led to the discovery of a broad range of particles: positrons, muons, pions, kaons and hyperons. The first observations on stratospheric balloons confirmed the origin of the showers of particles that had been detected with a series of ground detectors dispatched on a large area a few years before. These showers of particles are produced by primary cosmic rays mainly energetic protons colliding with nitrogen and oxygen atoms of the atmosphere. (A.C.)

  10. Cosmic radiation exposure and persistent cognitive dysfunction

    Science.gov (United States)

    Parihar, Vipan K.; Allen, Barrett D.; Caressi, Chongshan; Kwok, Stephanie; Chu, Esther; Tran, Katherine K.; Chmielewski, Nicole N.; Giedzinski, Erich; Acharya, Munjal M.; Britten, Richard A.; Baulch, Janet E.; Limoli, Charles L.

    2016-01-01

    The Mars mission will result in an inevitable exposure to cosmic radiation that has been shown to cause cognitive impairments in rodent models, and possibly in astronauts engaged in deep space travel. Of particular concern is the potential for cosmic radiation exposure to compromise critical decision making during normal operations or under emergency conditions in deep space. Rodents exposed to cosmic radiation exhibit persistent hippocampal and cortical based performance decrements using six independent behavioral tasks administered between separate cohorts 12 and 24 weeks after irradiation. Radiation-induced impairments in spatial, episodic and recognition memory were temporally coincident with deficits in executive function and reduced rates of fear extinction and elevated anxiety. Irradiation caused significant reductions in dendritic complexity, spine density and altered spine morphology along medial prefrontal cortical neurons known to mediate neurotransmission interrogated by our behavioral tasks. Cosmic radiation also disrupted synaptic integrity and increased neuroinflammation that persisted more than 6 months after exposure. Behavioral deficits for individual animals correlated significantly with reduced spine density and increased synaptic puncta, providing quantitative measures of risk for developing cognitive impairment. Our data provide additional evidence that deep space travel poses a real and unique threat to the integrity of neural circuits in the brain. PMID:27721383

  11. Cosmic radiation exposure and persistent cognitive dysfunction.

    Science.gov (United States)

    Parihar, Vipan K; Allen, Barrett D; Caressi, Chongshan; Kwok, Stephanie; Chu, Esther; Tran, Katherine K; Chmielewski, Nicole N; Giedzinski, Erich; Acharya, Munjal M; Britten, Richard A; Baulch, Janet E; Limoli, Charles L

    2016-10-10

    The Mars mission will result in an inevitable exposure to cosmic radiation that has been shown to cause cognitive impairments in rodent models, and possibly in astronauts engaged in deep space travel. Of particular concern is the potential for cosmic radiation exposure to compromise critical decision making during normal operations or under emergency conditions in deep space. Rodents exposed to cosmic radiation exhibit persistent hippocampal and cortical based performance decrements using six independent behavioral tasks administered between separate cohorts 12 and 24 weeks after irradiation. Radiation-induced impairments in spatial, episodic and recognition memory were temporally coincident with deficits in executive function and reduced rates of fear extinction and elevated anxiety. Irradiation caused significant reductions in dendritic complexity, spine density and altered spine morphology along medial prefrontal cortical neurons known to mediate neurotransmission interrogated by our behavioral tasks. Cosmic radiation also disrupted synaptic integrity and increased neuroinflammation that persisted more than 6 months after exposure. Behavioral deficits for individual animals correlated significantly with reduced spine density and increased synaptic puncta, providing quantitative measures of risk for developing cognitive impairment. Our data provide additional evidence that deep space travel poses a real and unique threat to the integrity of neural circuits in the brain.

  12. Does electromagnetic radiation accelerate galactic cosmic rays

    Science.gov (United States)

    Eichler, D.

    1977-01-01

    The 'reactor' theories of Tsytovich and collaborators (1973) of cosmic-ray acceleration by electromagnetic radiation are examined in the context of galactic cosmic rays. It is shown that any isotropic synchrotron or Compton reactors with reasonable astrophysical parameters can yield particles with a maximum relativistic factor of only about 10,000. If they are to produce particles with higher relativistic factors, the losses due to inverse Compton scattering of the electromagnetic radiation in them outweigh the acceleration, and this violates the assumptions of the theory. This is a critical restriction in the context of galactic cosmic rays, which have a power-law spectrum extending up to a relativistic factor of 1 million.

  13. Search for Antihelium in the Cosmic Radiation

    DEFF Research Database (Denmark)

    Streitmatter, R.E.; Barbier, L.M.; Christian, E.R.;

    1996-01-01

    The balloon-borne Isotope Matter-Antimatter Experiment (IMAX) was flown from Lynn Lake, Manitoba Canada on July 16-17, 1992. Sixteen hours of data were taken. Measurements of multiple dE/dX, rigidity, and time of flight were used to search for antihelium in the cosmic radiation. A report on the r...

  14. Higher Dimensional Radiation Collapse and Cosmic Censorship

    CERN Document Server

    Ghosh, S G

    2000-01-01

    We study the occurrence of naked singularities in the spherically symmetric collapse of radiation shells in a higher dimensional spacetime. The necessary conditions for the formation of a naked singularity or a black hole are obtained. The naked singularities are found to be strong in the Tipler's sense and thus violating cosmic censorship conjecture.

  15. Generation of Cosmic Magnetic Fields at Recombination

    CERN Document Server

    Hogan, C J

    2000-01-01

    It is shown that the standard cosmological model predicts ab initio generation of large-scale cosmic magnetic fields at the epoch of recombination of the primeval plasma. Matter velocities dominated by coherent flows on a scale $L\\approx 50h^{-1}(1+z)^{-1}$ Mpc lead to a dipole of radiation flux in the frame of the moving matter. Thomson scattering of the radiation differentially accelerates the electrons and ions, creating large-scale coherent electric currents and magnetic fields. This process is analyzed using magnetohydrodynamic equations which include a modification of Ohm's law describing the effect of Thomson drag on the electrons. The field strength saturates near equipartition with the baryon kinetic energy density at $B\\simeq 5\\times 10^{-5}$G. Magnetic stresses significantly damp baryonic motions at the epoch of last scattering, reducing the predicted background radiation anisotropy at small angles and changing estimates of fitted cosmological parameters. The field at late times retains its large-s...

  16. High-energy Gamma Rays from the Milky Way: Three-dimensional Spatial Models for the Cosmic-Ray and Radiation Field Densities in the Interstellar Medium

    Science.gov (United States)

    Porter, T. A.; Jóhannesson, G.; Moskalenko, I. V.

    2017-09-01

    High-energy γ-rays of interstellar origin are produced by the interaction of cosmic-ray (CR) particles with the diffuse gas and radiation fields in the Galaxy. The main features of this emission are well understood and are reproduced by existing CR propagation models employing 2D galactocentric cylindrically symmetrical geometry. However, the high-quality data from instruments like the Fermi Large Area Telescope reveal significant deviations from the model predictions on few to tens of degrees scales, indicating the need to include the details of the Galactic spiral structure and thus requiring 3D spatial modeling. In this paper, the high-energy interstellar emissions from the Galaxy are calculated using the new release of the GALPROP code employing 3D spatial models for the CR source and interstellar radiation field (ISRF) densities. Three models for the spatial distribution of CR sources are used that are differentiated by their relative proportion of input luminosity attributed to the smooth disk or spiral arms. Two ISRF models are developed based on stellar and dust spatial density distributions taken from the literature that reproduce local near- to far-infrared observations. The interstellar emission models that include arms and bulges for the CR source and ISRF densities provide plausible physical interpretations for features found in the residual maps from high-energy γ-ray data analysis. The 3D models for CR and ISRF densities provide a more realistic basis that can be used for the interpretation of the nonthermal interstellar emissions from the Galaxy.

  17. Hazards of cosmic radiation; Radiation cosmique: danger dans l'espace

    Energy Technology Data Exchange (ETDEWEB)

    Bonnet-Bidaud, J.M.; Dzitko, H

    2000-06-01

    The main limitations on long-distance space transport is neither the energy source nor the propulsion system but appears to be the protection of cosmonauts from radiation. Cosmic radiation is made up of protons (87%), alpha particles (12%) and heavy nuclei (1%), all these particles travel through interstellar space and come from the explosion of stars at the end of their life. The earth is protected from cosmic radiation by 3 natural shields: (i) the magnetic field generated by the solar wind, (ii) the earth magnetic field (magnetosphere), and (iii) the earth atmosphere, this elusive layer of air is equivalent to a 10 meter-high volume of water. Magnetosphere and atmosphere reduce the radiation dose by a factor 4000. According to a European directive (1996) air crews must be considered as radiation workers. (A.C.)

  18. Cosmic radiation algorithm utilizing flight time tables

    Energy Technology Data Exchange (ETDEWEB)

    Katja Kojo, M.Sc.; Mika Helminen, M.Sc.; Anssi Auvinen, M.D.Ph.D. [STUK - Radiation and Nuclear Safety Authority, Helsinki (Finland); Katja Kojo, M.Sc.; Anssi Auvinen, M.D.Ph.D. [Tampere Univ., School of Public Health (Finland); Gerhard Leuthold, D.Sc. [GSF - Research Center, Institute of Radiation Protection, Neuherberg (Germany)

    2006-07-01

    Cosmic radiation is considerably higher on cruising altitudes used in aviation than at ground level. Exposure to cosmic radiation may increase cancer risk among pilots and cabin crew. The International Commission on Radiation Protection (ICRP) has recommended that air crew should be classified as radiation workers. Quantification of cosmic radiation doses is necessary for assessment of potential health effects of such occupational exposure. For Finnair cabin crew (cabin attendants and stewards), flight history is not available for years prior to 1991 and therefore, other sources of information on number and type of flights have to be used. The lack of systematically recorded information is a problem for dose estimation for many other flight companies personnel as well. Several cosmic radiation dose estimations for cabin crew have been performed using different methods (e.g. 2-5), but they have suffered from various shortcomings. Retrospective exposure estimation is not possible with personal portable dosimeters. Methods that employ survey data for occupational dose assessment are prone to non-differential measurement error i.e. the cabin attendants do not remember correctly the number of past flights. Assessment procedures that utilize surrogate measurement methods i.e. the duration of employment, lack precision. The aim of the present study was to develop an assessment method for individual occupational exposure to cosmic radiation based on flight time tables. Our method provides an assessment method that does not require survey data or systematic recording of flight history, and it is rather quick, inexpensive, and possible to carry out in all other flight companies whose past time tables for the past periods exist. Dose assessment methods that employ survey data are prone to random error i.e. the cabin attendants do not remember correctly the number or types of routes that they have flown during the past. Our method avoids this since survey data are not needed

  19. Cosmic radiation exposure at aircraft crew workplaces

    Energy Technology Data Exchange (ETDEWEB)

    Latocha, M.; Beck, P.; Rollet, S. [ARC Seibersdorf Research, Seibersdorf (Austria); Latocha, M. [Institute of Nuclear Physics Polish Academy of Sciences, Krakow (Poland)

    2006-07-01

    E.U.R.A.D.O.S. working group W.G.5. on air crew dosimetry coordinated research of some 24 international institutes to exchange experimental data and results of calculations of the radiation exposure in aircraft altitudes due to cosmic radiation. The purpose was to provide a data-set for all European Union Member States for the assessment of individual doses, the validity of different approaches, and to provide an input to technical recommendations by the Article 31 group of experts and the European Commission. The results of this work have been recently published and are available for the international community. The radiation protection quantity of interest is effective dose, E (ISO), but the comparison of measurement results and the results of calculations, is done in terms of the operational quantity ambient dose equivalent, H{sup *}(10). This paper gives an overview of the E.U.R.A.D.O.S. Aircraft Crew In-Flight Database which was implemented under the responsibility of A.R.C. Seibersdorf research. It discusses calculation models for air crew dose assessment comparing them with measurements contained in this database. Further it presents current developments using updated information of galactic cosmic radiation proton spectra and new results of the recently finalized European research project D.O.S.M.A.X. on dosimetry of aircraft crew at solar maximum. (authors)

  20. Cosmic Ray transport in turbulent magnetic field

    CERN Document Server

    Yan, Huirong

    2013-01-01

    Cosmic ray (CR) transport and acceleration is determined by the properties of magnetic turbulence. Recent advances in MHD turbulence call for revisions in the paradigm of cosmic ray transport. We use the models of magnetohydrodynamic turbulence that were tested in numerical simulation, in which turbulence is injected at large scale and cascades to to small scales. We shall address the issue of the transport of CRs, both parallel and perpendicular to the magnetic field. We shall demonstrate compressible fast modes are dominant cosmic ray scatterer from both quasilinear and nonlinear theories. We shall also show that the self-generated wave growth by CRs are constrained by preexisting turbulence and discuss the process in detail in the context of shock acceleration at supernova remnants and their implications. In addition, we shall dwell on the nonlinear growth of kinetic gyroresonance instability of cosmic rays induced by large scale compressible turbulence. This gyroresonance of cosmic rays on turbulence is d...

  1. Anencephalus, drinking water, geomagnetism and cosmic radiation.

    Science.gov (United States)

    Archer, V E

    1979-01-01

    The mortality rates from anencephalus from 1950-1969 in Canadian cities are shown to be strongly correlated with city growth rate and with horizontal geomagnetic flux, which is directly related to the intensity of cosmic radiation. They are also shown to have some association with the magnesium content of drinking water. Prior work with these data which showed associations with magnesium in drinking water, mean income, latitude and longitude was found to be inadequate because it dismissed the observed geographic associations as having little biological meaning, and because the important variables of geomagnetism and city growth rate were overlooked.

  2. Kriging interpolating cosmic velocity field

    Science.gov (United States)

    Yu, Yu; Zhang, Jun; Jing, Yipeng; Zhang, Pengjie

    2015-10-01

    Volume-weighted statistics of large-scale peculiar velocity is preferred by peculiar velocity cosmology, since it is free of the uncertainties of galaxy density bias entangled in observed number density-weighted statistics. However, measuring the volume-weighted velocity statistics from galaxy (halo/simulation particle) velocity data is challenging. Therefore, the exploration of velocity assignment methods with well-controlled sampling artifacts is of great importance. For the first time, we apply the Kriging interpolation to obtain the volume-weighted velocity field. Kriging is a minimum variance estimator. It predicts the most likely velocity for each place based on the velocity at other places. We test the performance of Kriging quantified by the E-mode velocity power spectrum from simulations. Dependences on the variogram prior used in Kriging, the number nk of the nearby particles to interpolate, and the density nP of the observed sample are investigated. First, we find that Kriging induces 1% and 3% systematics at k ˜0.1 h Mpc-1 when nP˜6 ×1 0-2(h-1 Mpc )-3 and nP˜6 ×1 0-3(h-1 Mpc )-3 , respectively. The deviation increases for decreasing nP and increasing k . When nP≲6 ×1 0-4(h-1 Mpc )-3 , a smoothing effect dominates small scales, causing significant underestimation of the velocity power spectrum. Second, increasing nk helps to recover small-scale power. However, for nP≲6 ×1 0-4(h-1 Mpc )-3 cases, the recovery is limited. Finally, Kriging is more sensitive to the variogram prior for a lower sample density. The most straightforward application of Kriging on the cosmic velocity field does not show obvious advantages over the nearest-particle method [Y. Zheng, P. Zhang, Y. Jing, W. Lin, and J. Pan, Phys. Rev. D 88, 103510 (2013)] and could not be directly applied to cosmology so far. However, whether potential improvements may be achieved by more delicate versions of Kriging is worth further investigation.

  3. Magnetohydrodynamic experiments on cosmic magnetic fields

    CERN Document Server

    Stefani, Frank; Gerbeth, Gunter

    2008-01-01

    It is widely known that cosmic magnetic fields, including the fields of planets, stars, and galaxies, are produced by the hydromagnetic dynamo effect in moving electrically conducting fluids. It is less well known that cosmic magnetic fields play also an active role in cosmic structure formation by enabling outward transport of angular momentum in accretion disks via the magnetorotational instability (MRI). Considerable theoretical and computational progress has been made in understanding both processes. In addition to this, the last ten years have seen tremendous efforts in studying both effects in liquid metal experiments. In 1999, magnetic field self-excitation was observed in the large scale liquid sodium facilities in Riga and Karlsruhe. Recently, self-excitation was also obtained in the French "von Karman sodium" (VKS) experiment. An MRI-like mode was found on the background of a turbulent spherical Couette flow at the University of Maryland. Evidence for MRI as the first instability of an hydrodynamica...

  4. New type scalar fields for cosmic acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Kehagias, A; Pakis, S [Department of Physics, National Technical University of Athens, GR-15773, Zografou, Athens (Greece)

    2007-05-15

    We present a model where a non-conventional scalar field may act like dark energy and leads to cosmic acceleration. The latter is driven by an appropriate field configuration, which result in an effective cosmological constant. The potential role of such a scalar in the cosmological constant problem is also discussed.

  5. Radiative feedback and cosmic molecular gas: numerical method

    Science.gov (United States)

    Petkova, Margarita; Maio, Umberto

    2012-06-01

    We present the results from self-consistent numerical simulations of cosmic structure formation with a multifrequency radiative transfer scheme and non-equilibrium molecular chemistry of 13 primordial species (e-, H, H+, H-, He, He+, He++, H2, H?, D, D+, HD and HeH+), performed using the simulation code GADGET. We describe our implementation and we show tests for ionized sphere expansion in a static and dynamic density field around a central radiative source, and for cosmological abundance evolution coupled with the cosmic microwave background radiation. As a demonstrative application of radiative feedback on molecular gas, we also run cosmological simulations of early structure formation in a ˜1-Mpc sized box. Our tests agree well with analytical and numerical expectations. Consistent with other works, we find that ionization fronts from central sources can boost H2 fractions in shock-compressed gas. The tight dependence on H2 also leads to a corresponding boost of HD fractions. We see a strong lowering of the typical molecular abundances up to several orders of magnitude, which partially hinders further gas collapse of pristine neutral gas. This clearly suggests the need for reionized gas or metal cooling in the formation of the following generation of structures.

  6. Earth's magnetic field as a radiator to detect cosmic ray electrons of energy greater than 10 to the 12th eV

    Science.gov (United States)

    Balasubrahmanyan, V. K.; Stephens, S. A.

    1983-10-01

    Synchrotron emission by a high-energy electron in the geomagnetic field and its dependence upon different arrival directions over Palestine, Texas, where major balloon-borne experiments are being conducted, is studied. The dependence of detector response on the arrival direction of electron, the different criteria which are adopted to identify an electron event, the area of the detector, and the energy of the electron are discussed. An omnidirectional circular detector is used to examine whether it is possible to determine the energy of an electron without knowing its arrival direction. The collecting power of a detector is estimated as a function of the energy of electrons for different detector areas with different selection criteria, and this information is used to calculate the event rates expected by folding in the energy spectrum of cosmic ray electrons to show the viability of detecting cosmic ray electrons at energies greater than a few TeV.

  7. Consistency relation for cosmic magnetic fields

    DEFF Research Database (Denmark)

    Jain, R. K.; Sloth, M. S.

    2012-01-01

    to be extremely useful to test some recent calculations in the literature. Apart from primordial non-Gaussianity induced by the curvature perturbations, such a cross correlation might provide a new observational probe of inflation and can in principle reveal the primordial nature of cosmic magnetic fields. DOI...

  8. POLARBEAR constraints on cosmic birefringence and primordial magnetic fields

    Science.gov (United States)

    Ade, Peter A. R.; Arnold, Kam; Atlas, Matt; Baccigalupi, Carlo; Barron, Darcy; Boettger, David; Borrill, Julian; Chapman, Scott; Chinone, Yuji; Cukierman, Ari; Dobbs, Matt; Ducout, Anne; Dunner, Rolando; Elleflot, Tucker; Errard, Josquin; Fabbian, Giulio; Feeney, Stephen; Feng, Chang; Gilbert, Adam; Goeckner-Wald, Neil; Groh, John; Hall, Grantland; Halverson, Nils W.; Hasegawa, Masaya; Hattori, Kaori; Hazumi, Masashi; Hill, Charles; Holzapfel, William L.; Hori, Yasuto; Howe, Logan; Inoue, Yuki; Jaehnig, Gregory C.; Jaffe, Andrew H.; Jeong, Oliver; Katayama, Nobuhiko; Kaufman, Jonathan P.; Keating, Brian; Kermish, Zigmund; Keskitalo, Reijo; Kisner, Theodore; Kusaka, Akito; Le Jeune, Maude; Lee, Adrian T.; Leitch, Erik M.; Leon, David; Li, Yun; Linder, Eric; Lowry, Lindsay; Matsuda, Frederick; Matsumura, Tomotake; Miller, Nathan; Montgomery, Josh; Myers, Michael J.; Navaroli, Martin; Nishino, Haruki; Okamura, Takahiro; Paar, Hans; Peloton, Julien; Pogosian, Levon; Poletti, Davide; Puglisi, Giuseppe; Raum, Christopher; Rebeiz, Gabriel; Reichardt, Christian L.; Richards, Paul L.; Ross, Colin; Rotermund, Kaja M.; Schenck, David E.; Sherwin, Blake D.; Shimon, Meir; Shirley, Ian; Siritanasak, Praween; Smecher, Graeme; Stebor, Nathan; Steinbach, Bryan; Suzuki, Aritoki; Suzuki, Jun-ichi; Tajima, Osamu; Takakura, Satoru; Tikhomirov, Alexei; Tomaru, Takayuki; Whitehorn, Nathan; Wilson, Brandon; Yadav, Amit; Zahn, Alex; Zahn, Oliver; Polarbear Collaboration

    2015-12-01

    We constrain anisotropic cosmic birefringence using four-point correlations of even-parity E -mode and odd-parity B -mode polarization in the cosmic microwave background measurements made by the POLARization of the Background Radiation (POLARBEAR) experiment in its first season of observations. We find that the anisotropic cosmic birefringence signal from any parity-violating processes is consistent with zero. The Faraday rotation from anisotropic cosmic birefringence can be compared with the equivalent quantity generated by primordial magnetic fields if they existed. The POLARBEAR nondetection translates into a 95% confidence level (C.L.) upper limit of 93 nanogauss (nG) on the amplitude of an equivalent primordial magnetic field inclusive of systematic uncertainties. This four-point correlation constraint on Faraday rotation is about 15 times tighter than the upper limit of 1380 nG inferred from constraining the contribution of Faraday rotation to two-point correlations of B -modes measured by Planck in 2015. Metric perturbations sourced by primordial magnetic fields would also contribute to the B -mode power spectrum. Using the POLARBEAR measurements of the B -mode power spectrum (two-point correlation), we set a 95% C.L. upper limit of 3.9 nG on primordial magnetic fields assuming a flat prior on the field amplitude. This limit is comparable to what was found in the Planck 2015 two-point correlation analysis with both temperature and polarization. We perform a set of systematic error tests and find no evidence for contamination. This work marks the first time that anisotropic cosmic birefringence or primordial magnetic fields have been constrained from the ground at subdegree scales.

  9. Cosmic Radiation - An Aircraft Manufacturer's View

    Energy Technology Data Exchange (ETDEWEB)

    Hume, C

    1999-07-01

    The relevance and context of cosmic radiation to an aircraft maker Airbus Industrie are outlined. Some future developments in aircraft and air traffic are described, along with their possible consequences for exposure. (author)

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

    Science.gov (United States)

    Kusenko, Alexander

    2013-12-01

    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 ux of ultrahigh-energy cosmicrays 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.

  11. Testing inflation with the cosmic background radiation

    CERN Document Server

    Bond, J R

    1994-01-01

    In inflation cosmologies, cosmic structure develops through the gravitational instability of the inevitable quantum noise in primordial scalar fields. I show how the acceleration of the universe defines the shape of the primordial spectrum of gravitational metric and scalar field fluctuations. I assess how we can determine the shape and overall amplitude over the five decades or so of spatial wavelengths we can probe, and use current data ... to show how far we are in this program. Broad-band power amplitudes are given for CMB anisotropy detections up to spring 1994 ... I show that COBE band-powers found with full Bayesian analysis of the 53,90,31 a+b GHz first year DMR (and FIRS) maps are in good agreement, and are essentially independent of spectral slope and degree of (sharp) signal-to-noise filtering. Further, after (smooth) optimal signal-to-noise filtering (\\ie Weiner-filtering), the different DMR maps reveal the same large scale features and correlation functions with little dependence upon slope. Howe...

  12. Galactic cosmic ray induced radiation dose on terrestrial exoplanets

    CERN Document Server

    Atri, Dimitra; Griessmeier, Jean-Mathias

    2013-01-01

    This past decade has seen tremendous advancements in the study of extrasolar planets. Observations are now made with increasing sophistication from both ground and space based instruments, and exoplanets are characterized with increasing precision. There is a class of particularly interesting exoplanets, falling in the habitable zone, which is defined as the area around a star where the planet is capable of supporting liquid water on its surface. Theoretical calculations also suggest that close-in exoplanets are more likely to have weaker planetary magnetic fields, especially in case of super earths. Such exoplanets are subjected to a high flux of Galactic Cosmic Rays (GCRs) due to their weak magnetic moments. GCRs are energetic particles of astrophysical origin, which strike the planetary atmosphere and produce secondary particles, including muons, which are highly penetrating. Some of these particles reach the planetary surface and contribute to the radiation dose. Along with the magnetic field, another fac...

  13. Kriging Interpolating Cosmic Velocity Field

    CERN Document Server

    Yu, Yu; Jing, Yipeng; Zhang, Pengjie

    2015-01-01

    [abridge] Volume-weighted statistics of large scale peculiar velocity is preferred by peculiar velocity cosmology, since it is free of uncertainties of galaxy density bias entangled in mass-weighted statistics. However, measuring the volume-weighted velocity statistics from galaxy (halo/simulation particle) velocity data is challenging. For the first time, we apply the Kriging interpolation to obtain the volume-weighted velocity field. Kriging is a minimum variance estimator. It predicts the most likely velocity for each place based on the velocity at other places. We test the performance of Kriging quantified by the E-mode velocity power spectrum from simulations. Dependences on the variogram prior used in Kriging, the number $n_k$ of the nearby particles to interpolate and the density $n_P$ of the observed sample are investigated. (1) We find that Kriging induces $1\\%$ and $3\\%$ systematics at $k\\sim 0.1h{\\rm Mpc}^{-1}$ when $n_P\\sim 6\\times 10^{-2} ({\\rm Mpc}/h)^{-3}$ and $n_P\\sim 6\\times 10^{-3} ({\\rm Mpc...

  14. Galactic cosmic ray-induced radiation dose on terrestrial exoplanets.

    Science.gov (United States)

    Atri, Dimitra; Hariharan, B; Grießmeier, Jean-Mathias

    2013-10-01

    This past decade has seen tremendous advancements in the study of extrasolar planets. Observations are now made with increasing sophistication from both ground- and space-based instruments, and exoplanets are characterized with increasing precision. There is a class of particularly interesting exoplanets that reside in the habitable zone, which is defined as the area around a star where the planet is capable of supporting liquid water on its surface. Planetary systems around M dwarfs are considered to be prime candidates to search for life beyond the Solar System. Such planets are likely to be tidally locked and have close-in habitable zones. Theoretical calculations also suggest that close-in exoplanets are more likely to have weaker planetary magnetic fields, especially in the case of super-Earths. Such exoplanets are subjected to a high flux of galactic cosmic rays (GCRs) due to their weak magnetic moments. GCRs are energetic particles of astrophysical origin that strike the planetary atmosphere and produce secondary particles, including muons, which are highly penetrating. Some of these particles reach the planetary surface and contribute to the radiation dose. Along with the magnetic field, another factor governing the radiation dose is the depth of the planetary atmosphere. The higher the depth of the planetary atmosphere, the lower the flux of secondary particles will be on the surface. If the secondary particles are energetic enough, and their flux is sufficiently high, the radiation from muons can also impact the subsurface regions, such as in the case of Mars. If the radiation dose is too high, the chances of sustaining a long-term biosphere on the planet are very low. We have examined the dependence of the GCR-induced radiation dose on the strength of the planetary magnetic field and its atmospheric depth, and found that the latter is the decisive factor for the protection of a planetary biosphere.

  15. On the radiative and thermodynamic properties of the cosmic radiations using COBE FIRAS instrument data: I. Cosmic microwave background radiation

    Science.gov (United States)

    Fisenko, Anatoliy I.; Lemberg, Vladimir

    2014-07-01

    Using the explicit form of the functions to describe the monopole and dipole spectra of the Cosmic Microwave Background (CMB) radiation, the exact expressions for the temperature dependences of the radiative and thermodynamic functions, such as the total radiation power per unit area, total energy density, number density of photons, Helmholtz free energy density, entropy density, heat capacity at constant volume, and pressure in the finite range of frequencies v 1≤ v≤ v 2 are obtained. Since the dependence of temperature upon the redshift z is known, the obtained expressions can be simply presented in z representation. Utilizing experimental data for the monopole and dipole spectra measured by the COBE FIRAS instrument in the 60-600 GHz frequency interval at the temperature T=2.72548 K, the values of the radiative and thermodynamic functions, as well as the radiation density constant a and the Stefan-Boltzmann constant σ are calculated. In the case of the dipole spectrum, the constants a and σ, and the radiative and thermodynamic properties of the CMB radiation are obtained using the mean amplitude T amp=3.358 mK. It is shown that the Doppler shift leads to a renormalization of the radiation density constant a, the Stefan-Boltzmann constant σ, and the corresponding constants for the thermodynamic functions. The expressions for new astrophysical parameters, such as the entropy density/Boltzmann constant, and number density of CMB photons are obtained. The radiative and thermodynamic properties of the Cosmic Microwave Background radiation for the monopole and dipole spectra at redshift z≈1089 are calculated.

  16. Design of a transition radiation detector for cosmic rays

    Science.gov (United States)

    Hartmann, G.; Mueller, D.; Prince, T.

    1975-01-01

    Transition radiation detectors consisting of sandwiches of plastic foam radiators and multiwire proportional chambers can be used to identify cosmic ray particles with energies gamma ? E/mc-squared is greater than 10 to the 3rd and to measure their energy in the region gamma is roughly equal to 10 to the 3rd

  17. Comparative Measurements of Cosmic Radiation Monitors for Aircrew Exposure Assessment

    Science.gov (United States)

    Getley, I. L.; Bennett, L. G. I.; Boudreau, M. L.; Lewis, B. J.; Green, A. R.; Butler, A.; Takada, M.; Nakamura, T.

    Various commercially available electronic personal dosimeters (EPDs) have recently been flown on numerous scheduled airline flights in order to determine their viability as small, convenient monitors to measure cosmic radiation at altitude. Often, frequent flyers or airline crew will acquire such dosimeters and report the readings from their flights, without due regard for the mixed radiation field at altitude, which is different from the intended fields on land. A sampling of EPDs has been compared to two types of spectrometers, which measure the total radiation spectrum. The "HAWK" tissue equivalent proportional counter is considered a reference instrument and measures the total dose equivalent H*(10). The Liulin-4N and 4SN linear energy transfer spectrometers each have a silicon semiconductor-based PIN diode detector which provides an absorbed dose, D, but have been further developed to provide H*(10). A Thermo Electron FH41B and B-10, and EPD-N2, and several personal dosimeters (Fuji NRY-21 and NRF-20, and RADOS DIS-100) were also flown.

  18. Comparative Measurements of Cosmic Radiation Monitors for Aircrew Exposure Assessment

    Science.gov (United States)

    Getley, I. L.; Bennett, L. G. I.; Boudreau, M. L.; Lewis, B. J.; Green, A. R.; Butler, A.; Takada, M.; Nakamura, T.

    Various commercially available electronic personal dosimeters (EPDs) have recently been flown on numerous scheduled airline flights in order to determine their viability as small, convenient monitors to measure cosmic radiation at altitude. Often, frequent flyers or airline crew will acquire such dosimeters and report the readings from their flights, without due regard for the mixed radiation field at altitude, which is different from the intended fields on land. A sampling of EPDs has been compared to two types of spectrometers, which measure the total radiation spectrum. The “HAWK” tissue equivalent proportional counter is considered a reference instrument and measures the total dose equivalent H * (10). The Liulin-4N and 4SN linear energy transfer spectrometers each have a silicon semiconductor-based PIN diode detector which provides an absorbed dose, D, but have been further developed to provide H * (10). A Thermo Electron FH41B and B-10, and EPD-N2, and several personal dosimeters (Fuji NRY-21 and NRF-20, and RADOS DIS-100) were also flown.

  19. Cosmic Magnetic Fields: Observations and Prospects

    CERN Document Server

    Beck, Rainer

    2011-01-01

    Synchrotron emission, its polarization and its Faraday rotation at radio frequencies of 0.2-10 GHz are powerful tools to study the strength and structure of cosmic magnetic fields. The observational results are reviewed for spiral, barred and flocculent galaxies, the Milky Way, halos and relics of galaxy clusters, and for the intergalactic medium. Polarization observations with the forthcoming large radio telescopes will open a new era in the observation of cosmic magnetic fields and will help to understand their origin. At low frequencies, LOFAR (10-250 MHz) will allow us to map the structure of weak magnetic fields in the outer regions and halos of galaxies and galaxy clusters. Polarization at higher frequencies (1-10 GHz), as observed with the EVLA, ASKAP, MeerKAT, APERTIF and the SKA, will trace magnetic fields in the disks and central regions of nearby galaxies in unprecedented detail. Surveys of Faraday rotation measures of pulsars will map the Milky Way's magnetic field with high precision. All-sky sur...

  20. Water, air, Earth and cosmic radiation.

    Science.gov (United States)

    Bassez, Marie-Paule

    2015-06-01

    In the context of the origin of life, rocks are considered mainly for catalysis and adsorption-desorption processes. Here it is shown how some rocks evolve in energy and might induce synthesis of molecules of biological interest. Radioactive rocks are a source of thermal energy and water radiolysis producing molecular hydrogen, H2. Mafic and ultramafic rocks evolve in water and dissolved carbon dioxide releasing thermal energy and H2. Peridotites and basalts contain ferromagnesian minerals which transform through exothermic reactions with the generation of heat. These reactions might be triggered by any heating process such as radioactive decay, hydrothermal and subduction zones or post-shock of meteorite impacts. H2 might then be generated from endothermic hydrolyses of the ferromagnesian minerals olivine and pyroxene. In both cases of mafic and radioactive rocks, production of CO might occur through high temperature hydrogenation of CO2. CO, instead of CO2, was proven to be necessary in experiments synthesizing biological-type macromolecules with a gaseous mixture of CO, N2 and H2O. In the geological context, N2 is present in the environment, and the activation source might arise from cosmic radiation and/or radionuclides. Ferromagnesian and radioactive rocks might consequently be a starting point of an hydrothermal chemical evolution towards the abiotic formation of biological molecules. The two usually separate worlds of rocks and life are shown to be connected through molecular and thermodynamic chemical evolution. This concept has been proposed earlier by the author (Bassez J Phys: Condens Matter 15:L353-L361, 2003, 2008a, 2008b; Bassez Orig Life Evol Biosph 39(3-4):223-225, 2009; Bassez et al. 2011; Bassez et al. Orig Life Evol Biosph 42(4):307-316, 2012, Bassez 2013) without thermodynamic details. This concept leads to signatures of prebiotic chemistry such as radionuclides and also iron and magnesium carbonates associated with serpentine and/or talc

  1. Water, Air, Earth and Cosmic Radiation

    Science.gov (United States)

    Bassez, Marie-Paule

    2015-06-01

    In the context of the origin of life, rocks are considered mainly for catalysis and adsorption-desorption processes. Here it is shown how some rocks evolve in energy and might induce synthesis of molecules of biological interest. Radioactive rocks are a source of thermal energy and water radiolysis producing molecular hydrogen, H2. Mafic and ultramafic rocks evolve in water and dissolved carbon dioxide releasing thermal energy and H2. Peridotites and basalts contain ferromagnesian minerals which transform through exothermic reactions with the generation of heat. These reactions might be triggered by any heating process such as radioactive decay, hydrothermal and subduction zones or post-shock of meteorite impacts. H2 might then be generated from endothermic hydrolyses of the ferromagnesian minerals olivine and pyroxene. In both cases of mafic and radioactive rocks, production of CO might occur through high temperature hydrogenation of CO2. CO, instead of CO2, was proven to be necessary in experiments synthesizing biological-type macromolecules with a gaseous mixture of CO, N2 and H2O. In the geological context, N2 is present in the environment, and the activation source might arise from cosmic radiation and/or radionuclides. Ferromagnesian and radioactive rocks might consequently be a starting point of an hydrothermal chemical evolution towards the abiotic formation of biological molecules. The two usually separate worlds of rocks and life are shown to be connected through molecular and thermodynamic chemical evolution. This concept has been proposed earlier by the author (Bassez J Phys: Condens Matter 15:L353-L361, 2003, 2008a, 2008b; Bassez Orig Life Evol Biosph 39(3-4):223-225, 2009; Bassez et al. 2011; Bassez et al. Orig Life Evol Biosph 42(4):307-316, 2012, Bassez 2013) without thermodynamic details. This concept leads to signatures of prebiotic chemistry such as radionuclides and also iron and magnesium carbonates associated with serpentine and/or talc, which

  2. A Holographic Bound on Cosmic Magnetic Fields

    CERN Document Server

    McInnes, Brett

    2015-01-01

    Magnetic fields large enough to be observable are ubiquitous in astrophysics, even at extremely large length scales. This has led to the suggestion that such fields are seeded at very early (inflationary) times, and subsequently amplified by various processes involving, for example, dynamo effects. Many such mechanisms give rise to extremely large magnetic fields at the end of inflationary reheating, and therefore also during the quark-gluon plasma epoch of the early universe. Such plasmas have a well-known holographic description. We show that holography imposes an upper bound on the intensity of magnetic fields (scaled by the squared temperature) in these circumstances, and that the values expected in some models of cosmic magnetism come close to attaining that bound.

  3. A holographic bound on cosmic magnetic fields

    Directory of Open Access Journals (Sweden)

    Brett McInnes

    2015-03-01

    Full Text Available Magnetic fields large enough to be observable are ubiquitous in astrophysics, even at extremely large length scales. This has led to the suggestion that such fields are seeded at very early (inflationary times, and subsequently amplified by various processes involving, for example, dynamo effects. Many such mechanisms give rise to extremely large magnetic fields at the end of inflationary reheating, and therefore also during the quark–gluon plasma epoch of the early universe. Such plasmas have a well-known holographic description in terms of a thermal asymptotically AdS black hole. We show that holography imposes an upper bound on the intensity of magnetic fields (≈3.6×1018gauss at the hadronization temperature in these circumstances; this is above, but not far above, the values expected in some models of cosmic magnetogenesis.

  4. Galactic cosmic ray radiation levels in spacecraft on interplanetary missions

    Science.gov (United States)

    Shinn, J. L.; Nealy, J. E.; Townsend, L. W.; Wilson, J. W.; Wood, J.S.

    1994-01-01

    Using the Langley Research Center Galactic Cosmic Ray (GCR) transport computer code (HZETRN) and the Computerized Anatomical Man (CAM) model, crew radiation levels inside manned spacecraft on interplanetary missions are estimated. These radiation-level estimates include particle fluxes, LET (Linear Energy Transfer) spectra, absorbed dose, and dose equivalent within various organs of interest in GCR protection studies. Changes in these radiation levels resulting from the use of various different types of shield materials are presented.

  5. Radiometer system to map the cosmic background radiation

    Science.gov (United States)

    Gorenstein, M. V.; Muller, R. A.; Smoot, G. F.; Tyson, J. A.

    1978-01-01

    A 33-GHz airborne radiometer system has been developed to map large angular scale variations in the temperature of the 3 K cosmic background radiation. A ferrite circulator switches a room-temperature mixer between two antennas pointing 60 deg apart in the sky. In 40 min of observing, the radiometer can measure the anisotropy of the microwave background with an accuracy of plus or minus 1 mK rms, or about 1 part in 3000 of 3 K. The apparatus is flown in a U-2 jet to 20 km altitude where 33-GHz thermal microwave emission from the atmosphere is at a low level. A second radiometer, tuned to 54 GHz near oxygen emission lines, monitors spurious signals from residual atmospheric radiation. The antennas, which have an extremely low side-lobe response of less than -65 dB past 60 deg, reject anisotropic radiation from the earth's surface. Periodic interchange of the antenna positions and reversal of the aircraft's flight direction cancel equipment-based imbalances. The system has been operated successfully in U-2 aircraft flown from NASA-Ames at Moffett Field, Calif.

  6. Comparison of codes assessing radiation exposure of aircraft crew due to galactic cosmic radiation

    Energy Technology Data Exchange (ETDEWEB)

    Bottollier-Depois, Jean-Francois [IRSN Institute for Radiological Protection and Nuclear Safety, Fontenay-aux-Roses (France); Beck, Peter; Latocha, Marcin [AIT Austrian Institute of Technology, Vienna (Austria). Health and Environment Dept.; Mares, Vladimir; Ruehm, Werner [HMGU Helmholtz Zentrum Muenchen, Neuherberg (Germany). Inst. of Radiation Protection; Matthiae, Daniel [DLR Deutsches Zentrum fuer Luft- und Raumfahrt, Koeln (Germany). Inst. of Aerospace Medicine; Wissmann, Frank [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany)

    2012-05-15

    The aim of this report is to compare the doses and dose rates calculated by various codes assessing radiation exposure of aircraft crew due to cosmic radiation. Some of the codes are used routinely for radiation protection purposes while others are purely for scientific use. The calculations were done using a set of representative, real flight routes around the globe. The results are presented in an anonymous way. This comparison is of major importance since a real determination of effective dose is not possible and, therefore, the different methods used to evaluate effective doses can be compared. Eleven codes have been used in this comparison exercise organised by EURADOS on harmonization of aircrew dosimetry practices in European countries. Some of these codes are based on simulations of the secondary field of cosmic radiation by Monte Carlo techniques; others use analytical solutions of the problem, while still others are mainly based on a fit to experimental data. The overall agreement between the codes, however, is better than 20 % from the median.

  7. Biotropic Effect of Radiation Conditions on Orbital Cosmic Stations

    Science.gov (United States)

    Tsetlin, Vladimir; Ushakov, Igor; Gurieva, Tamar; Moisa, Svetlana; Zotin, Alexei; Lobanov, Alexei

    On the orbit of pilot orbital stations the crews undergo to low doses of chronic irradiation of cosmic radiation. The studying of radiobiological effects in different living systems were carried out in the ship’s side (OC “MIR” and ICS) and model surface experiments (power dose 200 mGy/day, density of neutron flow 30 particles/sm2 sec). It was shown that ionized radiation effects on embryonal development of Japanese quail embryo, inducing morphological disturbances in 12% of embryos. Many years ontogenesis (more 15 years of life in OC “MIR”) of microbial association evoked replacement of dominant types of micromycetes and bacterium and increasing of colony-formed units (CFU) in four orders. In laboratory low doses of γ-radiation induced the increasing of flight strain biomass of Aspergillus niger that corresponds to a radiation hormezis and also the increasing of radio-sensitivity. Moreover, under γ-neutron radiation were marked some deviations in morphology of supporting cell and numerous head falls of Aspergillus niger. The irradiation of Protozoa by low doses led to that spontaneous motion activity of spirostoms (Spirostomum ambiguum Ehbg.) accommodated in water processing by mixed γ-neutron radiation decreased twice that testified the fact that the definite factor of γ-neutron radiation effect is the changing of water medium state. In dry seeds of the highest plants wetting in water of preliminary low doses α-and γ-irradiation field in 100-300 times lower than geomagnetic one) the germination of seeds was higher approximately twice under γ-radiation. Low doses of γ-radiation decreased and α-radiation increased a negative influence of hypo-magnetic field on these processes. It was shown that hypomagnetic field occurred, in general, beneficial effect on the development of Planorbarius corneus: the portion of teratogenic effect is decreased, embryos initially occurred in hypomagnetic conditions were characterized by lowering mortality. Mobility

  8. Aircrew Exposure from Cosmic Radiation on Commercial Airline Routes

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, B.J.; McCall, M.J.; Green, A.R.; Bennett, L.G.I.; Pierre, M.; Schrewe, U.J.; O' Brien, K.; Felsberger, E

    2001-07-01

    As a result of the recent recommendations of the ICRP 60, and in anticipation of possible regulation on occupational exposure of Canadian-based aircrew, an extensive study was carried out by the Royal Military College of Canada over a one-year period to measure the cosmic radiation at commercial jet altitudes. A tissue-equivalent proportional counter was used to measure the ambient total dose equivalent rate on 62 flight routes, resulting in over 20,000 data points at one-minute intervals at various altitudes and geomagnetic latitudes (i.e. which span the full cut-off rigidity of the Earth's magnetic field). These data were then compared to similar experimental work at the Physikalisch Technische Bundesanstalt, using a different suite of equipment, to measure separately the low and high linear energy transfer components of the mixed radiation field, and to predictions with the LUIN transport code. All experimental and theoretical results were in excellent agreement. From these data, a semi-empirical model was developed to allow for the interpolation of the dose rate for any global position, altitude and date (i.e. heliocentric potential). Through integration of the dose rate function over a great circle flight path, a computer code was developed to provide an estimate of the total dose equivalent on any route worldwide at any period in the solar cycle. (author)

  9. A realistic treatment of geomagnetic Cherenkov radiation from cosmic ray air showers

    NARCIS (Netherlands)

    Werner, Klaus; de Vries, Krijn D.; Scholten, Olaf

    2012-01-01

    We present a macroscopic calculation of coherent electro-magnetic radiation from air showers initiated by ultra-high energy cosmic rays, based on currents obtained from three-dimensional Monte Carlo simulations of air showers in a realistic geo-magnetic field. We discuss the importance of a correct

  10. A macroscopic description of coherent geo-magnetic radiation from cosmic-ray air showers

    NARCIS (Netherlands)

    Scholten, O.; Werner, K.; Rusydi, F.

    2008-01-01

    We have developed a macroscopic description of coherent electromagnetic radiation from air showers initiated by ultra-high-energy cosmic rays due to the presence of the geo-magnetic field. This description offers it simple and direct insight in the relation between the properties of the air shower a

  11. How Space Radiation Risk from Galactic Cosmic Rays at the International Space Station Relates to Nuclear Cross Sections

    Science.gov (United States)

    Lin, Zi-Wei; Adams, J. H., Jr.

    2005-01-01

    Space radiation risk to astronauts is a major obstacle for long term human space explorations. Space radiation transport codes have thus been developed to evaluate radiation effects at the International Space Station (ISS) and in missions to the Moon or Mars. We study how nuclear fragmentation processes in such radiation transport affect predictions on the radiation risk from galactic cosmic rays. Taking into account effects of the geomagnetic field on the cosmic ray spectra, we investigate the effects of fragmentation cross sections at different energies on the radiation risk (represented by dose-equivalent) from galactic cosmic rays behind typical spacecraft materials. These results tell us how the radiation risk at the ISS is related to nuclear cross sections at different energies, and consequently how to most efficiently reduce the physical uncertainty in our predictions on the radiation risk at the ISS.

  12. Cosmic Rays Induced Background Radiation on Board of Commercial Flights

    CERN Document Server

    Pinilla, S; Núñez, L A

    2015-01-01

    The aim of this work is to determine the total integrated flux of cosmic radiation which a commercial aircraft is exposed to along specific flight trajectories. To study the radiation background during a flight and its modulation by effects such as altitude, latitude, exposure time and transient magnetospheric events, we perform simulations based on Magnetocosmics and CORSIKA codes, the former designed to calculate the geomagnetic effects on cosmic rays propagation and the latter allows us to simulate the development of extended air showers in the atmosphere. In this first work, by considering the total flux of cosmic rays from 5 GeV to 1 PeV, we obtained the expected integrated flux of secondary particles on board of a commercial airplane during the Bogot\\'a-Buenos Aires trip by point-to-point numerical integration.

  13. Gravitational Collapse of Radiating Dyon Solution and Cosmic Censorship Hypothesis

    Institute of Scientific and Technical Information of China (English)

    K.D.Patil; S.S.Zade; A.N.Mohod

    2008-01-01

    @@ We investigate the possibifity of cosmic censorship violation in the gravitational collapse of radiating dyon solution.It is shown that the final outcome of the collapse depends sensitively on the electric and magnetic charge parameters.The graphs of the outer apparent horizon,inner Cauchy horizon for different values of parameters are drawn.

  14. X-Ray Emission from Star-Forming Galaxies - Signatures of Cosmic Rays and Magnetic Fields

    CERN Document Server

    Schober, Jennifer; Klessen, Ralf S

    2014-01-01

    The evolution of magnetic fields in galaxies is still an open problem in astrophysics. In nearby galaxies the far-infrared-radio correlation indicates the coupling between magnetic fields and star formation. The correlation arises from the synchrotron emission of cosmic ray electrons traveling through the interstellar magnetic fields. However, with an increase of the interstellar radiation field (ISRF), inverse Compton scattering becomes the dominant energy loss mechanism of cosmic ray electrons with a typical emission frequency in the X-ray regime. The ISRF depends on the one hand on the star formation rate and becomes stronger in starburst galaxies, and on the other hand increases with redshift due to the evolution of the cosmic microwave background. With a model for the star formation rate of galaxies, the ISRF, and the cosmic ray spectrum, we can calculate the expected X-ray luminosity resulting from the inverse Compton emission. Except for galaxies with an active galactic nucleus the main additional cont...

  15. High energy radiation from black holes gamma rays, cosmic rays, and neutrinos

    CERN Document Server

    Dermer, Charles D

    2009-01-01

    Bright gamma-ray flares observed from sources far beyond our Milky Way Galaxy are best explained if enormous amounts of energy are liberated by black holes. The highest- energy particles in nature--the ultra-high-energy cosmic rays--cannot be confined by the Milky Way's magnetic field, and must originate from sources outside our Galaxy. Understanding these energetic radiations requires an extensive theoretical framework involving the radiation physics and strong-field gravity of black holes. In High Energy Radiation from Black Holes, Charles Dermer and Govind Menon present a systemat

  16. On the origin of cosmic magnetic fields

    Science.gov (United States)

    Kulsrud, Russell M.; Zweibel, Ellen G.

    2008-04-01

    We review the extensive and controversial literature concerning how the cosmic magnetic fields pervading nearly all galaxies and clusters of galaxies actually got started. Some observational evidence supports a hypothesis that the field is already moderately strong at the beginning of the life of a galaxy and its disc. One argument involves the chemical abundance of the light elements Be and B, while a second one is based on the detection of strong magnetic fields in very young high red shift galaxies. Since this problem of initial amplification of cosmic magnetic fields involves important plasma problems it is obvious that one must know the plasma in which the amplification occurs. Most of this review is devoted to this basic problem and for this it is necessary to devote ourselves to reviewing studies that take place in environments in which the plasma properties are most clearly understood. For this reason the authors have chosen to restrict themselves almost completely to studies of dynamos in our Galaxy. It is true that one can get a much better idea of the grand scope of galactic fields in extragalactic systems. However, most mature galaxies share the same dilemma as ours of overcoming important plasma problems. Since the authors are both trained in plasma physics we may be biased in pursuing this approach, but we feel it is justified by the above argument. In addition we feel we can produce a better review by staying close to that which we know best. In addition we have chosen not to consider the saturation problem of the galactic magnetic field since if the original dynamo amplification fails the saturation question does not arise. It is generally accepted that seed fields, whose strength is of order 10-20 G, easily spring up in the era preceding galaxy formation. Several mechanisms have been proposed to amplify these seed magnetic fields to a coherent structure with the microgauss strengths of the currently observed galactic magnetic fields. The standard

  17. Shielding from cosmic radiation for interplanetary missions Active and passive methods

    CERN Document Server

    Spillantini, P; Durante, M; Müller-Mellin, R; Reitz, G; Rossi, L; Shurshakov, V; Sorbi, M

    2007-01-01

    Shielding is arguably the main countermeasure for the exposure to cosmic radiation during interplanetary exploratory missions. However, shielding of cosmic rays, both of galactic or solar origin, is problematic, because of the high energy of the charged particles involved and the nuclear fragmentation occurring in shielding materials. Although computer codes can predict the shield performance in space, there is a lack of biological and physical measurements to benchmark the codes. An attractive alternative to passive, bulk material shielding is the use of electromagnetic fields to deflect the charged particles from the spacecraft target. Active shielding concepts based on electrostatic fields, plasma, or magnetic fields have been proposed in the past years, and should be revised based on recent technological improvements. To address these issues, the European Space Agency (ESA) established a Topical Team (TT) in 2002 including European experts in the field of space radiation shielding and superconducting magn...

  18. Spectator fields and their imprints on the Cosmic Microwave Background

    CERN Document Server

    Wang, Lingfei

    2016-01-01

    When a subdominant light scalar field ends slow roll during inflation, but well after the Hubble exit of the pivot scales, it may determine the cosmological perturbations. This thesis investigates how such a scalar field, the spectator, may leave its impact on the Cosmic Microwave Background (CMB) radiation and be consequently constrained. We first introduce the observables of the CMB, namely the power spectrum $P_\\zeta$, spectral index $n_s$ and its running $dn_s/d\\ln k$, the non-Gaussianities $f_{NL}$, $g_{NL}$ and $\\tau_{NL}$, and the lack of isocurvature and polarization modes. Based on these studies, we derive the cosmological predictions for the spectator scenario, revealing its consistency with the CMB for inflection point potentials, hyperbolic tangent potentials, and those with a sudden phase transition. In the end, we utilize the spectator scenario to explain the CMB power asymmetry, with a brief tachyonic fast-roll phase.

  19. Detection of Cosmic Microwave Background Structure in a Second Field with the Cosmic Anisotropy Telescope

    CERN Document Server

    Baker, J C; Hobson, M P; Jones, M E; Kneissl, R; Lasenby, A N; O'Sullivan, C M M; Pooley, G G; Rocha, G; Saunders, R; Scott, P F; Waldram, E M; Baker, Joanne C.; Grainge, Keith; Jones, Michael E.; Pooley, Guy; Saunders, Richard

    1999-01-01

    We describe observations at frequencies near 15 GHz of the second 2x2 degree field imaged with the Cambridge Cosmic Anisotropy Telescope (CAT). After the removal of discrete radio sources, structure is detected in the images on characteristic scales of about half a degree, corresponding to spherical harmonic multipoles in the approximate range l= 330--680. A Bayesian analysis confirms that the signal arises predominantly from the cosmic microwave background (CMB) radiation for multipoles in the lower half of this range; the average broad-band power in a bin with centroid l=422 (theta = 51') is estimated to be Delta_T/T=2.1^{+0.4}_{-0.5} x 10^{-5}. For multipoles centred on l=615 (theta =35'), we find contamination from Galactic emission is significant, and constrain the CMB contribution to the measured power in this bin to be Delta_T/T <2.0 x 10^{-5} (1-sigma upper limit). These new results are consistent with the first detection made by CAT in a completely different area of sky. Together with data from ot...

  20. Cosmic radiation dose measurements from the RaD-X flight campaign

    Science.gov (United States)

    Mertens, Christopher J.; Gronoff, Guillaume P.; Norman, Ryan B.; Hayes, Bryan M.; Lusby, Terry C.; Straume, Tore; Tobiska, W. Kent; Hands, Alex; Ryden, Keith; Benton, Eric; Wiley, Scott; Gersey, Brad; Wilkins, Richard; Xu, Xiaojing

    2016-10-01

    The NASA Radiation Dosimetry Experiment (RaD-X) stratospheric balloon flight mission obtained measurements for improving the understanding of cosmic radiation transport in the atmosphere and human exposure to this ionizing radiation field in the aircraft environment. The value of dosimetric measurements from the balloon platform is that they can be used to characterize cosmic ray primaries, the ultimate source of aviation radiation exposure. In addition, radiation detectors were flown to assess their potential application to long-term, continuous monitoring of the aircraft radiation environment. The RaD-X balloon was successfully launched from Fort Sumner, New Mexico (34.5°N, 104.2°W) on 25 September 2015. Over 18 h of flight data were obtained from each of the four different science instruments at altitudes above 20 km. The RaD-X balloon flight was supplemented by contemporaneous aircraft measurements. Flight-averaged dosimetric quantities are reported at seven altitudes to provide benchmark measurements for improving aviation radiation models. The altitude range of the flight data extends from commercial aircraft altitudes to above the Pfotzer maximum where the dosimetric quantities are influenced by cosmic ray primaries. The RaD-X balloon flight observed an absence of the Pfotzer maximum in the measurements of dose equivalent rate.

  1. Occupational cosmic radiation exposure and cancer in airline cabin crew.

    Energy Technology Data Exchange (ETDEWEB)

    Kojo, K.

    2013-03-15

    Cosmic radiation dose rates are considerably higher at cruising altitudes of airplanes than at ground level. Previous studies have found increased risk of certain cancers among aircraft cabin crew, but the results are not consistent across different studies. Despite individual cosmic radiation exposure assessment is important for evaluating the relation between cosmic radiation exposure and cancer risk, only few previous studies have tried to develop an exposure assessment method. The evidence for adverse health effects in aircrews due to ionizing radiation is inconclusive because quantitative dose estimates have not been used. No information on possible confounders has been collected. For an occupational group with an increased risk of certain cancers it is very important to assess if the risk is related to occupational exposure. The goal of this thesis was to develop two separate retrospective exposure assessment methods for occupational exposure to cosmic radiation. The methods included the assessment based on survey on flight histories and based on company flight timetables. Another goal was to describe the cancer incidence among aircraft cabin crew with a large cohort in four Nordic countries, i.e., Finland, Iceland, Norway, and Sweden. Also the contribution of occupational as well as non-occupational factors to breast and skin cancer risk among the cabin crew was studied with case-control studies. Using the survey method of cosmic radiation exposure assessment, the median annual radiation dose of Finnish airline cabin crew was 0.6 milliSievert (mSv) in the 1960s, 3.3 mSv in the 1970s, and 3.6 mSv in the 1980s. With the flight timetable method, the annual radiation dose increased with time being 0.7 mSv in the 1960 and 2.1 mSv in the 1995. With the survey method, the median career dose was 27.9 mSv and with the timetable method 20.8 mSv. These methods provide improved means for individual cosmic radiation exposure assessment compared to studies where cruder

  2. A relationship between galactic cosmic radiation and tree rings.

    Science.gov (United States)

    Dengel, Sigrid; Aeby, Dominik; Grace, John

    2009-11-01

    Here, we investigated the interannual variation in the growth rings formed by Sitka spruce (Picea sitchensis) trees in northern Britain (55 degrees N, 3 degrees W) over the period 1961-2005 in an attempt to disentangle the influence of atmospheric variables acting at different times of year. Annual growth rings, measured along the north radius of freshly cut (frozen) tree discs and climatological data recorded at an adjacent site were used in the study. Correlations were based on Pearson product-moment correlation coefficients between the annual growth anomaly and these climatic and atmospheric factors. Rather weak correlations between these variables and growth were found. However, there was a consistent and statistically significant relationship between growth of the trees and the flux density of galactic cosmic radiation. Moreover, there was an underlying periodicity in growth, with four minima since 1961, resembling the period cycle of galactic cosmic radiation. * We discuss the hypotheses that might explain this correlation: the tendency of galactic cosmic radiation to produce cloud condensation nuclei, which in turn increases the diffuse component of solar radiation, and thus increases the photosynthesis of the forest canopy.

  3. Cosmic magnetic fields from velocity perturbations in the early Universe

    CERN Document Server

    Betschart, G; Marklund, M; Betschart, Gerold; Dunsby, Peter K.S.; Marklund, Mattias

    2004-01-01

    We show, using a covariant and gauge-invariant charged multifluid perturbation scheme, that velocity perturbations of the matter-dominated dust Friedmann-Lemaitre-Robertson-Walker (FLRW) model can lead to the generation of cosmic magnetic fields. Moreover, using cosmic microwave background (CMB) constraints, it is argued that these fields can reach strengths of between 10^{-28} and 10^{-29} G at the time the dynamo mechanism sets in, making them plausible seed field candidates.

  4. Effects of microgravity and cosmic radiations on human T lymphocytes

    Directory of Open Access Journals (Sweden)

    P. Pippia

    2011-01-01

    Full Text Available In space living organisms, including cells, are affected by two new environmental conditions: microgravity and cosmic radiations. Several experiments in dedicated space missions and in simulated microgravity have shown that low gravity causes a dramatic depression of the mitogenic in vitro activation of T lymphocytes. The goal of this reserch was to determine in space (on board the International Space Station the ability of adherent monocytes to migrate, as well as to interact with T-cells. A reduced motility of the J-111 cells and changes in the structures of actin, tubulin and vinculin were observed. Moreover, we demonstrated that LFA-I/ICAM-I interactions occur in space and are dependent on activation time but show differences in number, arrangement and fluorescence intensity, depending on time and experimental conditions. In order to evaluate the effects of cosmic radiations on the gene expression in human T lymphocytes we exposed these cells to high quote cosmic radiation during two stratospheric balloon trans-mediterranean flights (BIRBA missions. The gene expression was analized by cDNA microarray hybridization technology. Activated T cells react to the ionizing stress by activating genes involved in cell cycle check-point, oxidative stress response, heat shock proteins production or by repressing denes involved in antigen recognition.

  5. A 3-Dimensional Analysis of the Galactic Gamma-Ray Emission Resulting from Cosmic-Ray Interactions with the Interstellar Gas and Radiation Fields

    Science.gov (United States)

    Sodroski, Thomas J.; Dwek, Eli (Technical Monitor)

    2001-01-01

    The contractor will provide support for the analysis of data under ADP (NRA 96-ADP- 09; Proposal No . 167-96adp). The primary task objective is to construct a 3-D model for the distribution of high-energy (20 MeV - 30 GeV) gamma-ray emission in the Galactic disk. Under this task the contractor will utilize data from the EGRET instrument on the Compton Gamma-Ray Observatory, H I and CO surveys, radio-continuum surveys at 408 MHz, 1420 MHz, 5 GHz, and 19 GHz, the COBE Diffuse Infrared Background Experiment (DIME) all-sky maps from 1 to 240 p, and ground-based B, V, J, H, and K photometry. The respective contributions to the gamma-ray emission from cosmic ray/matter interactions, inverse Compton scattering, and extragalactic emission will be determined.

  6. Cosmic Radiation – A Legal and Medical Issue in Aviation

    Directory of Open Access Journals (Sweden)

    Nataša Tomić-Petrović

    2012-03-01

    Full Text Available Research into the effects of different effects of radiation on human health has only recently been brought to light while the events in Hiroshima and Nagasaki have revived the interest in the research into the effects of ionizing radiation on organisms. The man has to live with radiation regardless of the risk. Protection efficiency is related with proper understanding of dangers coming from radiation and radiological contamination and protection methods. Knowledge in radiation protection is an important tool in the battle for survival on our planet. Our public today still seems insufficiently informed when it comes to hazards brought about by natural sources of radiation. Based on the published results it seems that the cosmic radiation hazard to passengers in contemporary air transport is nonexistent. Nevertheless, for some air crew categories (frequent intercontinental flights it is possible that annual absorbed doses are quite close to the doses absorbed by workers handling radiation sources, even the possibility of exceeding the prescribed levels is not inconceivable.

  7. Self-organization of cosmic radiation pressure instability

    Science.gov (United States)

    Hogan, Craig J.

    1991-01-01

    Under some circumstances the absorption of radiation momentum by an absorbing medium opens the possibility of a dynamical instability, sometimes called 'mock gravity'. Here, a simplified abstract model is studied in which the radiation source is assumed to remain spatially uniform, there is no reabsorption or reradiated light, and no forces other than radiative pressure act on the absorbing medium. It is shown that this model displays the unique feature of being not only unstable, but also self-organizing. The structure approaches a statistical dynamical steady state which is almost independent of initial conditions. In this saturated state the absorbers are concentrated in thin walls around empty bubbles; as the instability develops the big bubbles get bigger and the small ones get crushed and disappear. A linear analysis shows that to first order the thin walls are indeed stable structures. It is speculated that this instability may play a role in forming cosmic large-scale structure.

  8. Computation of cosmic radiation spectra and application to aircrew dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Song Jae

    2002-02-15

    Using the Monte Carlo radiation transport code FLUKA- 99, secondary cosmic radiation energy spectra and intensities of neutrons, protons, photons, electrons, and muons were calculated for different geographical latitude and longitude at the commercial jet's altitudes ranging from 27000 ft to 41000 ft. The Badhwar's proton model was used to construct the primary cosmic radiation spectrum and effect of the vertical cutoff rigidity was considered after spectra similar to those given in literature were resulted. By applying the effective dose conversion factors, a calculation tool for aircrew doses was developed. According to the resulting dose rate distribution, effective dose rate over North pole region is around three times of that over equator region due to the geomagnetical shielding effect. Illustrative assessments of aircrew doses were made for four distinctive routes of Korean airliners : Seoul - New York (USA), London (UK), Sydney (Australia) and Mumbai(India). The effective doses to aircrew incurred from a round trip were 0.047, 0.055, 0.018, and 0.018{mu}Sv, respectively. If aircrew work 500 hour s a year at the cruise altitude of a international airline, the individual dose would reach 2 mSv which is about the same size as the average annual dose of workers at a nuclear power plant.

  9. Magnetic fields and cosmic rays in clusters of galaxies

    CERN Document Server

    Kushnir, Doron; Waxman, Eli

    2009-01-01

    We argue that the observed correlation between the radio luminosity and the X-ray luminosity in radio emitting galaxy clusters implies that the radio emission is due to secondary electrons that are produced by p-p interactions and lose their energy by emitting synchrotron radiation in a strong magnetic field, B>(8\\pi a T_{CMB}^4)^{1/2}\\simeq 3\\muG. We construct a simple model that naturally explains the correlation, and show that the observations provide stringent constraints on cluster magnetic fields and cosmic rays (CRs): Within the cores of clusters, the ratio beta_{core} between the CR energy (per logarithmic particle energy interval) and the thermal energy is beta_{core}\\sim 10^{-4}; The source of these CRs is most likely the cluster accretion shock, which is inferred to deposit in CRs ~ a few percent of the thermal energy it generates; The diffusion time of 100 GeV CRs over scales \\gtrsim100 kpc is not short compared to the Hubble time; Cluster magnetic fields are enhanced by mergers to \\gtrsim 1 % of ...

  10. THE MYSTERY OF THE COSMIC DIFFUSE ULTRAVIOLET BACKGROUND RADIATION

    Energy Technology Data Exchange (ETDEWEB)

    Henry, Richard Conn [Henry A. Rowland Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, MD 21218 (United States); Murthy, Jayant [Indian Institute of Astrophysics, Bengaluru (India); Overduin, James; Tyler, Joshua, E-mail: henry@jhu.edu, E-mail: jmurthy@yahoo.com, E-mail: joverduin@towson.edu, E-mail: 97tyler@cardinalmail.cua.edu [Department of Physics, Astronomy and Geosciences, Towson University, Towson, MD 21252 (United States)

    2015-01-01

    The diffuse cosmic background radiation in the Galaxy Evolution Explorer far-ultraviolet (FUV, 1300-1700 Å) is deduced to originate only partially in the dust-scattered radiation of FUV-emitting stars: the source of a substantial fraction of the FUV background radiation remains a mystery. The radiation is remarkably uniform at both far northern and far southern Galactic latitudes and increases toward lower Galactic latitudes at all Galactic longitudes. We examine speculation that this might be due to interaction of the dark matter with the nuclei of the interstellar medium, but we are unable to point to a plausible mechanism for an effective interaction. We also explore the possibility that we are seeing radiation from bright FUV-emitting stars scattering from a ''second population'' of interstellar grains—grains that are small compared with FUV wavelengths. Such grains are known to exist, and they scatter with very high albedo, with an isotropic scattering pattern. However, comparison with the observed distribution (deduced from their 100 μm emission) of grains at high Galactic latitudes shows no correlation between the grains' location and the observed FUV emission. Our modeling of the FUV scattering by small grains also shows that there must be remarkably few such ''smaller'' grains at high Galactic latitudes, both north and south; this likely means simply that there is very little interstellar dust of any kind at the Galactic poles, in agreement with Perry and Johnston. We also review our limited knowledge of the cosmic diffuse background at ultraviolet wavelengths shortward of Lyα—it could be that our ''second component'' of the diffuse FUV background persists shortward of the Lyman limit and is the cause of the reionization of the universe.

  11. Earth's magnetic field as a radiator to detect cosmic ray electrons of energy greater than 10 to the 12th power eV

    Science.gov (United States)

    Stephens, S. A.; Balasubrahmanyan, V. K.

    1983-07-01

    The synchrotron emission by electrons of energy greater than a few TeV in Earth's magnetic field was examined. An omnidirectional detector, it is shown, can be satisfactorily used to estimate the energy. The collecting power of the detector, it is also shown, is a sensitive function of the area of the detector, the energy of electron, and the number of photons required to identify an electron. The event rate expected was calculated using an ideal balloon-borne detector.

  12. First measurements of cosmic muons with magnetic field in CMS

    Energy Technology Data Exchange (ETDEWEB)

    Biallass, P; Hebbeker, T; Hoepfner, K [Physics Institute IIIA, RWTH Aachen, Physikzentrum, 52056 Aachen (Germany)], E-mail: biallass@cern.ch

    2008-05-15

    The reconstruction of cosmic muons is important for testing and aligning the Compact Muon Solenoid experiment (CMS). In this context the Magnet Test and Cosmic Challenge (MTCC) with its comprehensive cosmic data taking periods including the presence of the 4 Tesla magnetic field has been like a dress rehearsal of detector hardware and software for the upcoming startup of the CMS detector. In addition to data taking also the comparison with simulated events is a crucial part of physics analyses. With respect to these tasks a dedicated cosmic muon generator, CMSCGEN, has been developed and compared with data from MTCC. As an example results from a reconstruction study using the barrel muon system are shown, comparing data and Monte Carlo prediction at the level of single chambers up to reconstructed tracks including momentum measurements.

  13. On the gravitational, dilatonic, and axionic radiative damping of cosmic strings

    Science.gov (United States)

    Buonanno, Alessandra; Damour, Thibault

    1999-07-01

    We study the radiation reaction on cosmic strings due to the emission of dilatonic, gravitational and axionic waves. After verifying the (on average) conservative nature of the time-symmetric self-interactions, we concentrate on the finite radiation damping force associated with the half-retarded minus half-advanced ``reactive'' fields. We reexamine a recent proposal of using a ``local back reaction approximation'' for the reactive fields. Using dimensional continuation as a convenient technical tool, we find, contrary to previous claims, that this proposal leads to antidamping in the case of the axionic field, and to zero (integrated) damping in the case of the gravitational field. One gets normal positive damping only in the case of the dilatonic field. We propose to use a suitably modified version of the local dilatonic radiation reaction as a substitute for the exact (nonlocal) gravitational radiation reaction. The incorporation of such a local approximation to gravitational radiation reaction should allow one to complete, in a computationally nonintensive way, string network simulations and to give better estimates of the amount and spectrum of gravitational radiation emitted by a cosmologically evolving network of massive strings.

  14. STARLIFE - An International Campaign to Study the Role of Galactic Cosmic Radiation in Astrobiological Model Systems

    Science.gov (United States)

    Moeller, Ralf; Raguse, Marina; Leuko, Stefan; Berger, Thomas; Hellweg, Christine Elisabeth; Fujimori, Akira; Okayasu, Ryuichi; Horneck, Gerda

    2017-02-01

    In-depth knowledge regarding the biological effects of the radiation field in space is required for assessing the radiation risks in space. To obtain this knowledge, a set of different astrobiological model systems has been studied within the STARLIFE radiation campaign during six irradiation campaigns (2013-2015). The STARLIFE group is an international consortium with the aim to investigate the responses of different astrobiological model systems to the different types of ionizing radiation (X-rays, γ rays, heavy ions) representing major parts of the galactic cosmic radiation spectrum. Low- and high-energy charged particle radiation experiments have been conducted at the Heavy Ion Medical Accelerator in Chiba (HIMAC) facility at the National Institute of Radiological Sciences (NIRS) in Chiba, Japan. X-rays or γ rays were used as reference radiation at the German Aerospace Center (DLR, Cologne, Germany) or Beta-Gamma-Service GmbH (BGS, Wiehl, Germany) to derive the biological efficiency of different radiation qualities. All samples were exposed under identical conditions to the same dose and qualities of ionizing radiation (i) allowing a direct comparison between the tested specimens and (ii) providing information on the impact of the space radiation environment on currently used astrobiological model organisms.

  15. X-ray emission from star-forming galaxies - signatures of cosmic rays and magnetic fields

    Science.gov (United States)

    Schober, J.; Schleicher, D. R. G.; Klessen, R. S.

    2015-01-01

    The evolution of magnetic fields in galaxies is still an open problem in astrophysics. In nearby galaxies the far-infrared-radio correlation indicates the coupling between magnetic fields and star formation. The correlation arises from the synchrotron emission of cosmic ray electrons travelling through the interstellar magnetic fields. However, with an increase of the interstellar radiation field (ISRF), inverse Compton scattering becomes the dominant energy loss mechanism of cosmic ray electrons with a typical emission frequency in the X-ray regime. The ISRF depends on the one hand on the star formation rate and becomes stronger in starburst galaxies, and on the other hand increases with redshift due to the higher temperature of the cosmic microwave background. With a model for the star formation rate of galaxies, the ISRF, and the cosmic ray spectrum, we can calculate the expected X-ray luminosity resulting from the inverse Compton emission. Except for galaxies with an active galactic nucleus the main additional contribution to the X-ray luminosity comes from X-ray binaries. We estimate this contribution with an analytical model as well as with an observational relation, and compare it to the pure inverse Compton luminosity. Using data from the Chandra Deep Field Survey and far-infrared observations from Atacama Large Millimeter/Submillimeter Array, we then determine upper limits for the cosmic ray energy. Assuming that the magnetic energy in a galaxy is in equipartition with the energy density of the cosmic rays, we obtain upper limits for the magnetic field strength. Our results suggest that the mean magnetic energy of young galaxies is similar to the one in local galaxies. This points towards an early generation of galactic magnetic fields, which is in agreement with current dynamo evolution models.

  16. Cosmic Ray Small Scale Anisotropies and Local Turbulent Magnetic Fields

    CERN Document Server

    López-Barquero, Vanessa; Xu, S; Desiati, P; Lazarian, A

    2015-01-01

    Cosmic ray anisotropy is observed in a wide energy range and at different angular scales by a variety of experiments. However, a comprehensive and satisfactory explanation has been elusive for over a decade now. The arrival distribution of cosmic rays on Earth is the convolution of the distribution of their sources and of the effects of geometry and properties of the magnetic field through which particles propagate. It is generally believed that the anisotropy topology at the largest angular scale is adiabatically shaped by diffusion in the structured interstellar magnetic field. On the contrary, the medium and small angular scale structure could be an effect of non diffusive propagation of cosmic rays in perturbed magnetic fields. In particular, a possible explanation of the observed small scale anisotropy observed at TeV energy scale, may come from the effect of particle scattering in turbulent magnetized plasmas. We perform numerical integration of test particle trajectories in low-$\\beta$ compressible mag...

  17. Simulation study on original characteristic spectrum of gamma radiation field cosmic-induced on lunabase rocks%月表岩石诱发γ辐射场原始谱特征模拟

    Institute of Scientific and Technical Information of China (English)

    赵剑锟; 葛良全; 张庆贤; 卢贞瑞; 罗耀耀

    2015-01-01

    Background: With large differences in mass density, Basalt, KREEP and Dunite are representative and widely distributed on lunar surface. Cosmic-inducedg-ray is produced after energetic particles (Galactic Cosmic Rays, GCR; Solar Particle Event, SPE) impacting on lunabase rocks.Purpose:This study aims at discovering the factors of cosmic-inducedg-ray spectrum and then utilizing the gamma ray data for lunar exploration more efficiency.Methods: A Monte Carlo model for proton-induced gamma ray is designed for the FLUKA simulation software to research cosmic-induced gamma original spectrum. Data analysis is applied to find the relationship between the characteristic spectrum and the densities of lunabase rocks.Results: The model is appropriate to simulate cosmic-inducedg-ray original spectrum. A great variety of original spectrum characteristics, such as energies of main elements, positron annihilation peak and radiation balanced peak, are acquired.Conclusion: A positive correlation is found between mass density of lunabase rock and characteristic peak intensity. These researches for original spectrum can be applied to comparing different lunar gamma-ray spectrum and rock mass density mapping on lunar surface as a reference.%玄武岩、克里普岩、橄榄岩在月球表面广泛分布,并具有一定的代表性,并且岩石密度差异较大,高能粒子(Galactic Cosmic Rays, GCR;Solar Particle Event, SPE)与岩石相互作用后激发g射线。利用蒙特卡罗软件FLUKA开展了月表高能质子诱发g射线的研究,获取了月表多种成岩主元素的特征g射线能量峰、正电子湮灭峰和g辐射平衡峰等原始谱特征信息。通过数据分析表明特征峰强度与月表岩石密度呈正相关。原始谱特征的研究不仅可以为不同系列绕月g数据的对比研究提供参考,也可为在全月表面进行基于核辐射方法的岩石密度填图研究提供理论支撑。

  18. Quantum collapse as a source of the seeds of cosmic structure during the radiation era

    Science.gov (United States)

    León, Gabriel; Landau, Susana J.; Piccirilli, María Pía

    2014-10-01

    The emergence of the seeds of cosmic structure, from a perfect isotropic and homogeneous Universe, has not been clearly explained by the standard version of inflationary models as the dynamics involved preserve the homogeneity and isotropy at all times. A proposal that attempts to deal with this problem, by introducing "the self-induced collapse hypothesis," has been introduced by D. Sudarsky and collaborators in previous papers. In all these works, the collapse of the wave function of the inflaton mode is restricted to occur during the inflationary period. In this paper, we analyze the possibility that the collapse happens during the radiation era. A viable model can be constructed under the condition that the inflaton field variable must be affected by the collapse while the momentum variable can or cannot be affected. Another condition to be fulfilled is that the time of collapse must be independent of k . However, when comparing with recent observational data, the predictions of the model cannot be distinguished from the ones provided by the standard inflationary scenario. The main reason for this arises from the requirement that primordial power spectrum obtained for the radiation era matches the amplitude of scalar fluctuations consistent with the latest cosmic microwave background observations. This latter constraint results in a limit on the possible times of collapse and ensures that the contribution of the inflaton field to the energy-momentum tensor is negligible compared to the contribution of the radiation fields.

  19. Regional cosmic ray induced ionization and geomagnetic field changes

    Directory of Open Access Journals (Sweden)

    G. A. Kovaltsov

    2007-08-01

    Full Text Available Cosmic ray induced ionization (CRII is an important factor of outer space influences on atmospheric properties. Variations of CRII are caused by two different processes – solar activity variations, which modulate the cosmic ray flux in interplanetary space, and changes of the geomagnetic field, which affects the cosmic ray access to Earth. Migration of the geomagnetic dipole axis may greatly alter CRII in some regions on a time scale of centuries and longer. Here we present a study of CRII regional effects of the geomagnetic field changes during the last millennium for two regions: Europe and the Far East. We show that regional effects of the migration of the geomagnetic dipole axis may overcome global changes due to solar activity variations.

  20. Lyman α radiation hydrodynamics of galactic winds before cosmic reionization

    Science.gov (United States)

    Smith, Aaron; Bromm, Volker; Loeb, Abraham

    2017-01-01

    The dynamical impact of Lyman α (Lyα) radiation pressure on galaxy formation depends on the rate and duration of momentum transfer between Lyα photons and neutral hydrogen gas. Although photon trapping has the potential to multiply the effective force, ionizing radiation from stellar sources may relieve the Lyα pressure before appreciably affecting the kinematics of the host galaxy or efficiently coupling Lyα photons to the outflow. We present self-consistent Lyα radiation-hydrodynamics simulations of high-z galaxy environments by coupling the Cosmic Lyα Transfer code (COLT) with spherically symmetric Lagrangian frame hydrodynamics. The accurate but computationally expensive Monte Carlo radiative transfer calculations are feasible under the one-dimensional approximation. The initial starburst drives an expanding shell of gas from the centre and in certain cases, Lyα feedback significantly enhances the shell velocity. Radiative feedback alone is capable of ejecting baryons into the intergalactic medium (IGM) for protogalaxies with a virial mass of Mvir ≲ 108 M⊙. We compare the Lyα signatures of Population III stars with 105 K blackbody emission to that of direct collapse black holes with a non-thermal Compton-thick spectrum and find substantial differences if the Lyα spectra are shaped by gas pushed by Lyα radiation-driven winds. For both sources, the flux emerging from the galaxy is reprocessed by the IGM such that the observed Lyα luminosity is reduced significantly and the time-averaged velocity offset of the Lyα peak is shifted redward.

  1. Real-Time Aircraft Cosmic Ray Radiation Exposure Predictions from the NAIRAS Model

    Science.gov (United States)

    Mertens, C. J.; Tobiska, W.; Kress, B. T.; Xu, X.

    2012-12-01

    The Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS) is a prototype operational model for predicting commercial aircraft radiation exposure from galactic and solar cosmic rays. NAIRAS predictions are currently streaming live from the project's public website, and the exposure rate nowcast is also available on the SpaceWx smartphone app for iPhone, IPad, and Android. Cosmic rays are the primary source of human exposure to high linear energy transfer radiation at aircraft altitudes, which increases the risk of cancer and other adverse health effects. Thus, the NAIRAS model addresses an important national need with broad societal, public health and economic benefits. There is also interest in extending NAIRAS to the LEO environment to address radiation hazard issues for the emerging commercial spaceflight industry. The processes responsible for the variability in the solar wind, interplanetary magnetic field, solar energetic particle spectrum, and the dynamical response of the magnetosphere to these space environment inputs, strongly influence the composition and energy distribution of the atmospheric ionizing radiation field. Real-time observations are required at a variety of locations within the geospace environment. The NAIRAS model is driven by real-time input data from ground-, atmospheric-, and space-based platforms. During the development of the NAIRAS model, new science questions and observational data gaps were identified that must be addressed in order to obtain a more reliable and robust operational model of atmospheric radiation exposure. The focus of this talk is to present the current capabilities of the NAIRAS model, discuss future developments in aviation radiation modeling and instrumentation, and propose strategies and methodologies of bridging known gaps in current modeling and observational capabilities.

  2. Survey on the Monto Carlo Calculation of the Atmospheric Cosmic Radiation Field%空间辐射场蒙特卡罗模拟计算方法研究

    Institute of Scientific and Technical Information of China (English)

    李春娟; 陈军; 张伟华

    2011-01-01

    The calculation of the radiation environment caused by galactic cosmic rays with Monto Carlo method has been investigated. The model setup method and the variance reduction technics usually used in the calculation are analysized. The spectra of secondary particles resulting from interactions of primary galactic cosmic rays with the nuclei in the atmosphere calculated by Roesler with FLUKA code and by Anid with MCNPX code are discussed and compared to a large variety of experimental data. One method to assess the dose on arbitrary routes is proposed, and the properties of the radiation environment caused by galactic cosmic rays are discussed.%对利用蒙特卡罗方法对由银河宇宙射线引起的空间辐射场各成分进行计算的方法进行了调研,对计算模型的建立以及计算过程中通常使用的方差减小技术进行分析,给出了美国的Roesler等人利用FLUKA程序以及加拿大Anid等人利用MCNPX程序计算得到的由银河宇宙射线引起的空间辐射场各量值及其与实验结果的比较,验证了计算方法与计算模型的可靠性.对任意航线空间辐射场剂量分布预评估方法进行分析,给出了由银河宇宙射线引起的空间辐射场的基本特征.

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

    Science.gov (United States)

    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

    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

  4. Far Infrared Spectrometry of the Cosmic Background Radiation

    Science.gov (United States)

    Mather, J. C.

    1974-01-01

    I describe two experiments to measure the cosmic background radiation near 1 mm wavelength. The first was a ground-based search for spectral lines, made with a Fabry-Perot interferometer and an InSb detector. The second is a measurement of the spectrum from 3 to 18 cm{sup -1}, made with a balloon-borne Fourier transform spectrometer. It is a polarizing Michelson interferometer, cooled in liquid helium, and operated with a germanium bolometer. I give the theory of operation, construction details, and experimental results. The first experiment was successfully completed but the second suffered equipment malfunction on its first flight. I describe the theory of Fourier transformations and give a new understanding of convolutional phase correction computations. I discuss for infrared bolometer calibration procedures, and tabulate test results on nine detectors. I describe methods of improving bolometer sensitivity with immersion optics and with conductive film blackening.

  5. Thick Galactic Cosmic Radiation Shielding Using Atmospheric Data

    Science.gov (United States)

    Youngquist, Robert C.; Nurge, Mark A.; Starr, Stanley O.; Koontz, Steven L.

    2013-01-01

    NASA is concerned with protecting astronauts from the effects of galactic cosmic radiation and has expended substantial effort in the development of computer models to predict the shielding obtained from various materials. However, these models were only developed for shields up to about 120 g!cm2 in thickness and have predicted that shields of this thickness are insufficient to provide adequate protection for extended deep space flights. Consequently, effort is underway to extend the range of these models to thicker shields and experimental data is required to help confirm the resulting code. In this paper empirically obtained effective dose measurements from aircraft flights in the atmosphere are used to obtain the radiation shielding function of the earth's atmosphere, a very thick shield. Obtaining this result required solving an inverse problem and the method for solving it is presented. The results are shown to be in agreement with current code in the ranges where they overlap. These results are then checked and used to predict the radiation dosage under thick shields such as planetary regolith and the atmosphere of Venus.

  6. Cosmic expansion from boson and fermion fields

    Energy Technology Data Exchange (ETDEWEB)

    De Souza, Rudinei C; Kremer, Gilberto M, E-mail: rudijantsch@gmail.com, E-mail: kremer@fisica.ufpr.br [Departamento de Fisica, Universidade Federal do Parana, Curitiba (Brazil)

    2011-06-21

    This paper consists in analyzing an action that describes boson and fermion fields minimally coupled to the gravity and a common matter field. The self-interaction potentials of the fields are not chosen a priori but from the Noether symmetry approach. The Noether forms of the potentials allow the boson field to play the role of dark energy and matter and the fermion field to behave as standard matter. The constant of motion and the cyclic variable associated with the Noether symmetry allow the complete integration of the field equations, whose solution produces a universe with alternated periods of accelerated and decelerated expansion.

  7. Cosmic expansion from boson and fermion fields

    CERN Document Server

    de Souza, Rudinei C

    2011-01-01

    This paper consists in analyzing an action that describes boson and fermion fields minimally coupled to the gravity and a common matter field. The self-interaction potentials of the fields are not chosen a priori but from the Noether symmetry approach. The Noether forms of the potentials allow the boson field to play the role of dark energy and matter and the fermion field to behave as standard matter. The constant of motion and the cyclic variable associated with the Noether symmetry allow the complete integration of the field equations, whose solution produces a Universe with alternated periods of accelerated and decelerated expansion.

  8. A non-parametric model for the cosmic velocity field

    NARCIS (Netherlands)

    Branchini, E; Teodoro, L; Frenk, CS; Schmoldt, [No Value; Efstathiou, G; White, SDM; Saunders, W; Sutherland, W; Rowan-Robinson, M; Keeble, O; Tadros, H; Maddox, S; Oliver, S

    1999-01-01

    We present a self-consistent non-parametric model of the local cosmic velocity field derived from the distribution of IRAS galaxies in the PSCz redshift survey. The survey has been analysed using two independent methods, both based on the assumptions of gravitational instability and linear biasing.

  9. Observations of the diffuse UV radiation field

    Science.gov (United States)

    Murthy, Jayant; Henry, R. C.; Feldman, P. D.; Tennyson, P. D.

    1989-01-01

    Spectra are presented for the diffuse UV radiation field between 1250 to 3100 A from eight different regions of the sky, which were obtained with the Johns Hopkins UVX experiment. UVX flew aboard the Space Shuttle Columbia (STS-61C) in January 1986 as part of the Get-Away Special project. The experiment consisted of two 1/4 m Ebert-Fastie spectrometers, covering the spectral range 1250 to 1700 A at 17 A resolution and 1600 to 3100 A at 27 A resolution, respectively, with a field of view of 4 x .25 deg, sufficiently small to pick out regions of the sky with no stars in the line of sight. Values were found for the diffuse cosmic background ranging in intensity from 300 to 900 photons/sq cm/sec/sr/A. The cosmic background is spectrally flat from 1250 to 3100 A, within the uncertainties of each spectrometer. The zodiacal light begins to play a significant role in the diffuse radiation field above 2000 A, and its brightness was determined relative to the solar emission. Observed brightnesses of the zodiacal light in the UV remain almost constant with ecliptic latitude, unlike the declining visible brightnesses, possibly indicating that those (smaller) grains responsible for the UV scattering have a much more uniform distribution with distance from the ecliptic plane than do those grains responsible for the visible scattering.

  10. Anisotropy in the cosmic radiation at TeV energy

    CERN Document Server

    Iuppa, Roberto

    2013-01-01

    In recent years very important results were obtained from cosmic ray experiments about the arrival direction distribution of primaries in the TeV energy range. As most of these particles are charged nuclei, they are deflected by the magnetic field they pass through before reaching the Earth surface, the effect of the Lorentz force being inversely proportional to the particle energy. As far as the local interstellar medium is known, the gyroradius of a 10 TeV proton is expected to be only 100 a.u., small enough to make the arrival direction distribution isotropic. Since 1930s a "large scale" (90{\\deg}-120{\\deg}) anisotropy is known to exist, generally interpreted as the combined effect of sources far away and magnetic fields nearby. Nonetheless, in the last decade experiments like Tibet-ASg, Milagro, ARGO-YBJ and IceCube discovered structures as wide as 10{\\deg}-30{\\deg} all over the sky at ~ 10 TeV energy, what is unexplainable within the standard model of cosmic rays. In this paper a review of the most recen...

  11. Quantum optical dipole radiation fields

    CERN Document Server

    Stokes, Adam

    2016-01-01

    We introduce quantum optical dipole radiation fields defined in terms of photon creation and annihilation operators. These fields are identified through their spatial dependence, as the components of the total fields that survive infinitely far from the dipole source. We use these radiation fields to perturbatively evaluate the electromagnetic radiated energy-flux of the excited dipole. Our results indicate that the standard interpretation of a bare atom surrounded by a localised virtual photon cloud, is difficult to sustain, because the radiated energy-flux surviving infinitely far from the source contains virtual contributions. It follows that there is a clear distinction to be made between a radiative photon defined in terms of the radiation fields, and a real photon, whose identification depends on whether or not a given process conserves the free energy. This free energy is represented by the difference between the total dipole-field Hamiltonian and its interaction component.

  12. Extragalactic Cosmic Rays and Magnetic Fields: Facts and Fiction

    CERN Document Server

    Ensslin, T A

    2005-01-01

    A critical discussion of our knowledge about extragalactic cosmic rays and magnetic fields is attempted. What do we know for sure? What are our prejudices? How do we confront our models with the observations? How can we assess the uncertainties in our modeling and in our observations? Unfortunately, perfect answers to these questions can not be given. Instead, I describe efforts I am involved in to gain reliable information about relativistic particles and magnetic fields in extragalactic space.

  13. Acceleration and Particle Field Interactions of Cosmic Rays II: Calculations

    CERN Document Server

    Tawfik, A; Ghoneim, M T; Hady, A

    2010-01-01

    Based on the generic acceleration model, which suggests different types of electromagnetic interactions between the cosmic charged particles and the different configurations of the electromagnetic (plasma) fields, the ultra high energy cosmic rays are studied. The plasma fields are assumed to vary, spatially and temporally. The well-known Fermi accelerations are excluded. Seeking for simplicity, it is assumed that the energy loss due to different physical processes is negligibly small. The energy available to the plasma sector is calculated in four types of electromagnetic fields. It has been found that the drift in a time--varying magnetic field is extremely energetic. The energy scale widely exceeds the Greisen-Zatsepin-Kuzmin (GZK) cutoff. The polarization drift in a time--varying electric field is also able to raise the energy of cosmic rays to an extreme value. It can be compared with the Hillas mechanism. The drift in a spatially--varying magnetic field is almost as strong as the polarization drift. The...

  14. Cosmic Web of Galaxies in the COMOS Field

    Science.gov (United States)

    Darvish, Behnam; Martin, Christopher D.; Mobasher, Bahram; Scoville, Nicholas; Sobral, David; COSMOS science Team

    2017-01-01

    We use a mass complete sample of galaxies with accurate photometric redshifts in the COSMOS field to estimate the density field and to extract the components of the cosmic web. The comic web extraction algorithm relies on the signs and the ratio of eigenvalues of the Hessian matrix and is enable to integrate the density field into clusters, filaments and the field. We show that at z 0.8, the trend flattens out. For star-forming galaxies only, the median star-formation rate declines by ~ 0.3-0.4 dex from the field to clusters for both satellites and centrals, only at z < 0.5. We argue that for satellite galaxies, the main role of the cosmic web environment is to control their star-forming/quiescent fraction, whereas for centrals, it is mainly to control their overall star-formation rate. Given these, we suggest that most satellite galaxies experience a rapid quenching mechanism as they fall from the field into clusters through the channel of filaments, whereas for central galaxies, it is mostly due to a slow quenching process. Our preliminary results highlight the importance of the large-scale cosmic web on the evolution of galaxies.

  15. High Precision Cosmology with the Cosmic Background Radiation

    Science.gov (United States)

    Farhang, Marzieh

    In this thesis we investigate the two cosmic epochs of inflation and recombination, through their imprints on the temperature and polarization anisotropies of the cosmic microwave background radiation. To probe the early universe we develop a map-based maximum-likelihood estimator to measure the amplitude of inflation-induced gravity waves, parametrized by r, from the cosmic microwave background (CMB) polarization maps. Being optimal by construction, the estimator avoids E-B mixing, a possible source of contamination in the tiny B-mode detection, the target of many current and near future CMB experiments. We explore the leakage from the E- to the B-mode of polarization by using this estimator to study the linear response of the B-mode signal at different scales to variations in the E- mode power. Similarly, for various observational cases, we probe the dependence of r measurement on the signal from different scales of E and B polarization. The estimator is used to make forecasts for Spider-like and Planck-like experimental specifications and to investigate the sky-coverage optimization of the Spider-like case. We compare the forecast errors on r to the results from a similar multipole-based estimator which, by ignoring the mode-mixing, sets a lower limit on the achievable error on r. We find that an experiment with Spider-like specifications with fsky ˜ 0:02--0:2 could place a 2sigma r ≈ 0:014 bound (˜ 95% CL), which rises to 0:02 with an ℓ-dependent foreground residual left over from an assumed efficient component separation. For the Planck-like survey, a Galaxy-masked ( fsky = 0:75) sky would give 2sigmar ≈ 0:015, rising to ≈ 0:05 with the foreground residuals. We also use a novel information-based framework to compare how different generations of CMB experiments reveal information about the early universe, through their measurements of r. We also probe the epoch of recombination by investigating possible fluctuations in the free electron fraction Xe

  16. Constraining the cosmic radiation density due to lepton number

    Energy Technology Data Exchange (ETDEWEB)

    Mangano, Gianpiero [Istituto Nazionale di Fisica Nucleare - Sezione di Napoli Complesso Universitario di Monte S. Angelo, I-80126 Napoli (Italy); Miele, Gennaro [Istituto Nazionale di Fisica Nucleare - Sezione di Napoli Complesso Universitario di Monte S. Angelo, I-80126 Napoli (Italy); Dipartimento di Scienze Fisiche, Università di Napoli Federico II Complesso Universitario di Monte S. Angelo, I-80126 Napoli (Italy); Pastor, Sergio [Instituto de Física Corpuscular (CSIC-Universitat de València), Ed. Institutos de Investigación, Apdo. correos 22085, E-46071 Valencia (Spain); Pisanti, Ofelia [Istituto Nazionale di Fisica Nucleare - Sezione di Napoli Complesso Universitario di Monte S. Angelo, I-80126 Napoli (Italy); Dipartimento di Scienze Fisiche, Università di Napoli Federico II Complesso Universitario di Monte S. Angelo, I-80126 Napoli (Italy); Sarikas, Srdjan [Dipartimento di Scienze Fisiche, Università di Napoli Federico II Complesso Universitario di Monte S. Angelo, I-80126 Napoli (Italy); Max-Planck-Institut für Physik (Werner-Heisenberg-Institut) Föhringer Ring 6, 80802 München (Germany)

    2013-04-15

    The cosmic energy density in the form of radiation before and during Big Bang Nucleosynthesis is typically parameterized in terms of the effective number of neutrinos N{sub eff}, and it is a key parameters in cosmological models slightly more general than the successful minimal ΛCDM scenario. This quantity, in case of no extra degrees of freedom, depends upon the chemical potential and the temperature characterizing the three active neutrino distributions, as well as by their possible non-thermal features. We summarize here the results of a recent analysis to determine the BBN bound on N{sub eff} from primordial neutrino–antineutrino asymmetries, with a careful treatment of the dynamics of neutrino oscillations, and considering quite a wide range for the total lepton number in the neutrino sector, η{sub ν}=η{sub ν{sub e}}+η{sub ν{sub μ}}+η{sub ν{sub τ}} and the initial electron neutrino asymmetry η{sub ν{sub e}{sup in}}. Comparing these results with the forthcoming measurement of N{sub eff} by the Planck satellite will give insight on the nature of the radiation content of the universe.

  17. POLARBEAR Constraints on Cosmic Birefringence and Primordial Magnetic Fields

    CERN Document Server

    Ade, Peter A R; Atlas, Matt; Baccigalupi, Carlo; Barron, Darcy; Boettger, David; Borrill, Julian; Chapman, Scott; Chinone, Yuji; Cukierman, Ari; Dobbs, Matt; Ducout, Anne; Dunner, Rolando; Elleflot, Tucker; Errard, Josquin; Fabbian, Giulio; Feeney, Stephen; Feng, Chang; Gilbert, Adam; Goeckner-Wald, Neil; Groh, John; Hall, Grantland; Halverson, Nils W; Hasegawa, Masaya; Hattori, Kaori; Hazumi, Masashi; Hill, Charles; Holzapfel, William L; Hori, Yasuto; Howe, Logan; Inoue, Yuki; Jaehnig, Gregory C; Jaffe, Andrew H; Jeong, Oliver; Katayama, Nobuhiko; Kaufman, Jonathan P; Keating, Brian; Kermish, Zigmund; Keskitalo, Reijo; Kisner, Theodore; Kusaka, Akito; Jeune, Maude Le; Lee, Adrian T; Leitch, Erik M; Leon, David; Li, Yun; Linder, Eric; Lowry, Lindsay; Matsuda, Frederick; Matsumura, Tomotake; Miller, Nathan; Montgomery, Josh; Myers, Michael J; Navaroli, Martin; Nishino, Haruki; Okamura, Takahiro; Paar, Hans; Peloton, Julien; Pogosian, Levon; Poletti, Davide; Puglisi, Giuseppe; Raum, Christopher; Rebeiz, Gabriel; Reichardt, Christian L; Richards, Paul L; Ross, Colin; Rotermund, Kaja M; Schenck, David E; Sherwin, Blake D; Shimon, Meir; Shirley, Ian; Siritanasak, Praween; Smecher, Graeme; Stebor, Nathan; Steinbach, Bryan; Suzuki, Aritoki; Suzuki, Jun-ichi; Tajima, Osamu; Takakura, Satoru; Tikhomirov, Alexei; Tomaru, Takayuki; Whitehorn, Nathan; Wilson, Brandon; Yadav, Amit; Zahn, Alex; Zahn, Oliver

    2015-01-01

    We constrain anisotropic cosmic birefringence using four-point correlations of even-parity $E$-mode and odd-parity $B$-mode polarization in the cosmic microwave background measurements made by the POLARBEAR experiment in its first season of observations. We find that the anisotropic cosmic birefringence signal from any parity violating processes is consistent with zero. The Faraday rotation from anisotropic cosmic birefringence can be compared with the equivalent quantity generated by primordial magnetic fields if they existed. The POLARBEAR non-detection translates into a 95% confidence level (C.L.) upper limit of 93 nano-Gauss (nG) on the amplitude of an equivalent primordial magnetic field inclusive of systematic uncertainties. This four-point correlation constraint on Faraday rotation is about 15 times tighter than the upper limit of 1380 nG inferred from constraining the contribution of Faraday rotation to two-point correlations of $B$-modes measured by Planck in 2015. Metric perturbations sourced by pri...

  18. Cosmic-ray source of runaway electrons in thundercloud electric field.

    Science.gov (United States)

    Babich, L. P.; Bochkov, E. I.; Kutsyk, I. M.

    2008-12-01

    To increase an accuracy of numerical simulations of the high-altitude and high-energy electric phenomena in thunderstorm atmosphere basing on the electric breakdown combining the cosmic-ray effects and relativistic runaway electron (RE) avalanches it is necessary to have accurate source of seed REs produced by cosmic rays. We calculated the source using the Monte-Carlo technique. Actually a number of secondary electrons was calculated with energies above the runaway threshold depending on the field overvoltage relative to the minimum of the drag force affecting electrons. The cosmic radiation propagation through the atmosphere was simulated based on simplified model of the nuclear cascade: a cosmic proton was assumed to completely lose its energy in the first interaction with air nuclei, producing 15 pions with equal energies. The flux of primary radiation was divided into 20 angular groups containing equal number of particles. In view of the lack of the experimental data on the RE source it is impossible to directly estimate the accuracy of the obtained source. Therefore the model reliability was verified by comparing results of secondary radiation calculations with known experimental altitude variations in the secondary cosmic rays and their spectra. The source was calculated as the specific generation rate of the secondary electrons by cosmic radiation dependent on electric field overvoltage and the altitude above the Earth's surface. It is recommended as a source of relativistic runaway electron avalanches in numerical simulations of electric discharges in atmosphere controlled by REs in thunderstorm fields and their emissions: optical, gamma and neutrons. The source already was used to simulate the high-altitude discharge and its emissions. In particular, the calculated gamma-ray pulses (photon numbers and spectra, pulse duration) agree with detected terrestrial gamma-ray flashes (TGFs). Conclusions of the published analyses (Cummer and Lyons, 2005; Cummer et

  19. Cosmic string interactions induced by gauge and scalar fields

    CERN Document Server

    Kabat, Daniel

    2012-01-01

    We study the interaction between two parallel cosmic strings induced by gauge fields and by scalar fields with non-minimal couplings to curvature. For small deficit angles the gauge field behaves like a collection of non-minimal scalars with a specific value for the non-minimal coupling. We check this equivalence by computing the interaction energy between strings at first order in the deficit angles. This result provides another physical context for the "contact terms" which play an important role in the renormalization of black hole entropy due to a spin-1 field.

  20. 9,400 years of cosmic radiation and solar activity from ice cores and tree rings

    National Research Council Canada - National Science Library

    Friedhelm Steinhilber; Jose A. Abreu; Jürg Beer; Irene Brunner; Marcus Christl; Hubertus Fischer; Ulla Heikkilä; Peter W. Kubik; Mathias Mann; Ken G. McCracken; Heinrich Miller; Hiroko Miyahara; Hans Oerter; Frank Wilhelms

    2012-01-01

    .... Cosmic-ray produced radionuclides, such as ¹⁰Be and ¹⁴C which are stored in polar ice cores and tree rings, offer the unique opportunity to reconstruct the history of cosmic radiation and solar activity over many millennia...

  1. Cosmic background radiation anisotropy in an open inflation, cold dark matter cosmogony

    Science.gov (United States)

    Kamionkowski, Marc; Ratra, Bharat; Spergel, David N.; Sugiyama, Naoshi

    1994-01-01

    We compute the cosmic background radiation anisotropy, produced by energy-density fluctuations generated during an early epoch of inflation, in an open cosmological model based on the cold dark matter scenario. At Omega(sub 0) is approximately 0.3-0.4, the Cosmic Background Explorer (COBE) normalized open model appears to be consistent with most observations.

  2. Skewon field and cosmic wave propagation

    CERN Document Server

    Ni, Wei-Tou

    2013-01-01

    For the study of the gravitational coupling of electromagnetism and the equivalence principle, we have used the spacetime constitutive tensor density {chi}ijkl, and discovered the nonmetric (axion) part (A){chi}ijkl (equal to {phi}eijkl) of {chi}ijkl worthy investigation. Since we have used Lagrangian formalism, {chi}ijkl is effectively symmetric under the interchange of index pairs, ij and kl, and has 21 independent degrees of freedom. Hehl, Obukhov and Rubilar have started from charge-flux formalism to study electromagnetism, discovered the antisymmetric part (Sk){chi}ijkl (15 degrees of freedom) of {chi}ijkl under the interchange of index pairs ij and kl worthy investigation, and called it skewon field. In this paper, we study the propagation of the Hehl-Obukhov-Rubilar skewon field in weak gravity field/dilute matter or with weak violation of the Einstein Equivalence Principle (EEP), and further classify it into Type I and Type II skewons. From the dispersion relation we show that no dissipation/no amplif...

  3. Inside the Meteorite — Bacterial Spore Survival After Exposure to Galactic Cosmic Radiation

    Science.gov (United States)

    Moeller, R.; Berger, T.; Matthiä, D.; Okayasu, R.; Kato, T.; Kitamura, H.; Reitz, G.

    2010-04-01

    Based on their unique resistance to various space parameters, bacterial spores are one of the model systems used for astrobiological studies. In our research, we studied the response of Bacillus subtilis spores to the exposure of galactic cosmic radiation.

  4. Multilayer Polymeric Shielding to Protect Humans from Galactic Cosmic Radiation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In Sub-topic X4.01, NASA has identified a need for advanced radiation-shielding materials and structures to protect humans from the hazards of galactic cosmic...

  5. Evaluation of viscera and other tissues. [cosmic radiation effects

    Science.gov (United States)

    Ellis, J. T.; Kraft, L. M.; Lushbaugh, C. C.; Humason, G. L.; Hartroft, W. S.; Porta, E. A.; Bailey, O. T.; Greep, R. O.; Leach, C. S.; Laird, T.

    1975-01-01

    Histopathological findings in the lungs, livers, bone marrows, small intestines, gonads, kidneys, and other tissues of the four pocket mice (Perognathus longimembris) that survived the Apollo XVII flight were evaluated in the light of their immediate environment and as targets of HZE cosmic ray particles. Results of this study failed to disclose changes that could be ascribed to the HZE particle radiation. Decreased numbers of erythropoietic cells in the bone marrow of the flight mice were probably related to the increased oxygen pressure. The small intestine showed no changes. Ovaries and testes appeared normal. Two of the three surviving male flight mice displayed early stages of spermatogenesis, just as ground-based controls did at the same season. Abnormalities were also not found in the thyroid, parathyroids, adrenals, or kidneys. The status of the juxtaglomerular apparatus could not be evaluated. The lungs exhibited nonspecific slight reactions. A variety of incidental lesions were noted in the livers of both the flight mice and their controls. The heart muscle showed nothing that could be regarded as pathological. Sections of skeletal muscle examined were free from significant change.

  6. A Cosmic Microwave Background Radiation Polarimeter Using Superconducting Bearings

    CERN Document Server

    Hanany, S; Johnson, B; Jones, T; Hull, J R; Ma, K B

    2003-01-01

    Measurements of the polarization of the cosmic microwave background (CMB) radiation are expected to significantly increase our understanding of the early universe. We present a design for a CMB polarimeter in which a cryogenically cooled half wave plate rotates by means of a high-temperature superconducting (HTS) bearing. The design is optimized for implementation in MAXIPOL, a balloon-borne CMB polarimeter. A prototype bearing, consisting of commercially available ring-shaped permanent magnet and an array of YBCO bulk HTS material, has been constructed. We measured the coefficient of friction as a function of several parameters including temperature between 15 and 80 K, rotation frequency between 0.3 and 3.5 Hz, levitation distance between 6 and 10 mm, and ambient pressure between 10^{-7} and 1 torr. The low rotational drag of the HTS bearing allows rotations for long periods of time with minimal input power and negligible wear and tear thus making this technology suitable for a future satellite mission.

  7. Radiative feedback and cosmic molecular gas: the role of different radiative sources

    CERN Document Server

    Maio, U; De Lucia, G; Borgani, S

    2016-01-01

    We present results from multifrequency radiative hydrodynamical chemistry simulations addressing primordial star formation and related stellar feedback from various populations of stars, stellar energy distributions (SEDs) and initial mass functions. Spectra for massive stars, intermediate-mass stars and regular solar-like stars are adopted over a grid of 150 frequency bins and consistently coupled with hydrodynamics, heavy-element pollution and non-equilibrium species calculations. Powerful massive population III stars are found to be able to largely ionize H and, subsequently, He and He$^+$, causing an inversion of the equation of state and a boost of the Jeans masses in the early intergalactic medium. Radiative effects on star formation rates are between a factor of a few and 1 dex, depending on the SED. Radiative processes are responsible for gas heating and photoevaporation, although emission from soft SEDs has minor impacts. These findings have implications for cosmic gas preheating, primordial direct-c...

  8. Radiative feedback and cosmic molecular gas: the role of different radiative sources

    Science.gov (United States)

    Maio, Umberto; Petkova, Margarita; De Lucia, Gabriella; Borgani, Stefano

    2016-08-01

    We present results from multifrequency radiative hydrodynamical chemistry simulations addressing primordial star formation and related stellar feedback from various populations of stars, stellar spectral energy distributions (SEDs) and initial mass functions. Spectra for massive stars, intermediate-mass stars and regular solar-like stars are adopted over a grid of 150 frequency bins and consistently coupled with hydrodynamics, heavy-element pollution and non-equilibrium species calculations. Powerful massive Population III stars are found to be able to largely ionize H and, subsequently, He and He+, causing an inversion of the equation of state and a boost of the Jeans masses in the early intergalactic medium. Radiative effects on star formation rates are between a factor of a few and 1 dex, depending on the SED. Radiative processes are responsible for gas heating and photoevaporation, although emission from soft SEDs has minor impacts. These findings have implications for cosmic gas preheating, primordial direct-collapse black holes, the build-up of `cosmic fossils' such as low-mass dwarf galaxies, the role of active galactic nuclei during reionization, the early formation of extended discs and angular-momentum catastrophe.

  9. Characterization of Silicon Photomultiplier Detectors using Cosmic Radiation

    Science.gov (United States)

    Zavala, Favian; Castro, Juan; Niduaza, Rexavalmar; Wedel, Zachary; Fan, Sewan; Ritt, Stefan; Fatuzzo, Laura

    2014-03-01

    The silicon photomultiplier light detector has gained a lot of attention lately in fields such as particle physics, astrophysics, and medical physics. Its popularity stems from its lower cost, compact size, insensitivity to magnetic fields, and its excellent ability to distinguish a quantized number of photons. They are normally operated at room temperature and biased above their breakdown voltages. As such, they may also exhibit properties that may hinder their optimal operation which include a thermally induced high dark count rate, after pulse effects, and cross talk from photons in nearby pixels. At this poster session, we describe our data analysis and our endeavor to characterize the multipixel photon counter (MPPC) detectors from Hamamatsu under different bias voltages and temperature conditions. Particularly, we describe our setup which uses cosmic rays to induce scintillation light delivered to the detector by wavelength shifting optical fibers and the use of a fast 1 GHz waveform sampler, the domino ring sampler (DRS4) digitizer board. Department of Education grant number P031S90007.

  10. The Unified First law in "Cosmic Triad" Vector Field Scenario

    CERN Document Server

    Zhang, Yi; Zhu, Zong-Hong

    2011-01-01

    In this letter, we try to apply the unified first law to the "cosmic triad" vector field scenario both in the minimal coupling case and in the non-minimalcoupling case. After transferring the non-minimally coupling action in Jordan frame to Einstein frame, the correct dynamical equation (Friedmann equation) is gotten in a thermal equilibrium process by using the already existing entropy while the entropy in the non-minimal coupled "cosmic triad" scenario has not been derived. And after transferring the variables back to Jordan frame, the corresponding Friedmann equation is demonstrated to be correct. For complete arguments, we also calculate the related Misner-Sharp energy in Jordan and Einstein frames.

  11. Cosmic radiation measurements on the Foton-M4 satellite by passive detectors

    Science.gov (United States)

    Strádi, Andrea; Pálfalvi, József K.; Szabó, Julianna; Pázmándi, Tamás; Ivanova, Olga A.; Shurshakov, Vyacheslav A.

    2017-02-01

    The Russian Foton spacecraft was designed to deliver scientific experiments to low Earth orbit and return them safely to the ground for further analysis. During the 44-d Foton-M4 satellite mission in 2014 several passive cosmic ray detectors were exposed outside (in a single holder) and inside (in 4 locations) the recoverable capsule to study the radiation field. The applied thermoluminescent detectors (TLDs) are more sensitive to the particles with LET under 10 keV μm-1, while the solid state nuclear track detectors (SSNTDs) measure the particles having LET over this value. According to our measurements the average internal absorbed dose rate varied between 374-562 μGy/day for low LET radiation and 40-52 μGy/day for high LET radiation. Outside the capsule the dose rate was much higher, 1078 μGy/day for low LET radiation and 75 μGy/day for high LET radiation. Within the paper the obtained absorbed dose rates has been compared to those measured on the previous Foton-M flights, during the Bion-M1 mission and in the Columbus module of the International Space Station.

  12. On Divergence in Radiation Fields

    CERN Document Server

    Fricke, Joerg

    2016-01-01

    Three thought experiments demonstrate that under certain circumstances radiation fields have to be attenuated or amplified multiplicatively in order not to violate the conservation of energy. Modulation of radiation by means other than superposition is theoretically made possible by plugging additional terms into the source slots of the Maxwell equations. Modulated radiation would enable the well focused stimulation of neurons for diagnostic and therapeutic purposes.

  13. DNDO Report: Predicting Solar Modulation Potentials for Modeling Cosmic Background Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Behne, Patrick Alan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-08-08

    The modeling of the detectability of special nuclear material (SNM) at ports and border crossings requires accurate knowledge of the background radiation at those locations. Background radiation originates from two main sources, cosmic and terrestrial. Cosmic background is produced by high-energy galactic cosmic rays (GCR) entering the atmosphere and inducing a cascade of particles that eventually impact the earth’s surface. The solar modulation potential represents one of the primary inputs to modeling cosmic background radiation. Usosokin et al. formally define solar modulation potential as “the mean energy loss [per unit charge] of a cosmic ray particle inside the heliosphere…” Modulation potential, a function of elevation, location, and time, shares an inverse relationship with cosmic background radiation. As a result, radiation detector thresholds require adjustment to account for differing background levels, caused partly by differing solar modulations. Failure to do so can result in higher rates of false positives and failed detection of SNM for low and high levels of solar modulation potential, respectively. This study focuses on solar modulation’s time dependence, and seeks the best method to predict modulation for future dates using Python. To address the task of predicting future solar modulation, we utilize both non-linear least squares sinusoidal curve fitting and cubic spline interpolation. This material will be published in transactions of the ANS winter meeting of November, 2016.

  14. DNDO Report: Predicting Solar Modulation Potentials for Modeling Cosmic Background Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Behne, Patrick Alan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-08-08

    The modeling of the detectability of special nuclear material (SNM) at ports and border crossings requires accurate knowledge of the background radiation at those locations. Background radiation originates from two main sources, cosmic and terrestrial. Cosmic background is produced by high-energy galactic cosmic rays (GCR) entering the atmosphere inducing a cascade of particles that eventually impact the earth’s surface. The solar modulation potential represents one of the primary inputs to modeling cosmic background radiation. Usosokin et al. formally define solar modulation potential as “the mean energy loss [per unit charge] of a cosmic ray particle inside the heliosphere…” Modulation potential, a function of elevation, location, and time, shares an inverse relationship with cosmic background radiation. As a result, radiation detector thresholds require adjustment to account for differing background levels, caused partly by differing solar modulations. Failure to do so can result in higher rates of false positives and failed detection of SNM for low and high levels of solar modulation potential, respectively. This study focuses on solar modulation’s time dependence and seeks the best method to predict modulation for future dates using Python. To address the task of predicting future solar modulation, we utilize both non-linear least squares sinusoidal curve fitting and cubic spline interpolation. This material will be published in transactions of the ANS winter meeting of November, 2016.

  15. Scientific results from the cosmic background explorer (COBE). [Information on cosmic radiation

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, C.L.; Boggess, N.W.; Cheng, E.S.; Hauser, M.G.; Kelsall, T.; Mather, J.C.; Moseley, S.H. Jr.; Shafer, R.A.; Silverberg, R.F. (NASA/Goddard Space Flight Center, Greenbelt, MD (United States)); Murdock, T.L. (General Research Corp., Danvers, MA (United States)); Smoot, G.F. (Lawrence Berkeley Lab., CA (United States)); Weiss, R. (Massachusetts Inst. of Technology, Cambridge (United States)); Wright, E.L. (Univ. of California, Los Angeles (United States))

    1993-06-01

    The National Aeronautics and Space Administration (NASA) has flown the COBE satellite to observe the Big Bang and the subsequent formation of galaxies and large-scale structure. Data from the Far-Infrared Absolute Spectrophotometer (FIRAS) show that the spectrum of the cosmic microwave background is that of a black body of temperature T = 2.73 [+-] 0.06 K, with no deviation from a black-body spectrum greater than 0.25% of the peak brightness. The data from the Differential Microwave Radiometers (DMR) show statistically significant cosmic microwave background anisotropy, consistent with a scale-invariant primordial density fluctuation spectrum. Measurements from the Diffuse Infrared Background Experiment (DIRBE) provide new conservation upper limits to the cosmic infrared background. Extensive modeling of solar system and galactic infrared foregrounds is required for further improvement in the cosmic infrared background limits. 104 refs., 1 tab.

  16. Milestones in the Observations of Cosmic Magnetic Fields

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Magnetic fields are observed everywhere in the universe. In this review,we concentrate on the observational aspects of the magnetic fields of Galactic and extragalactic objects. Readers can follow the milestones in the observations of cosmic magnetic fields obtained from the most important tracers of magnetic fields,namely, the star-light polarization, the Zeeman effect, the rotation measures (RMs,hereafter) of extragalactic radio sources, the pulsar RMs, radio polarization observations, as well as the newly implemented sub-mm and mm polarization capabilities.The magnetic field of the Galaxy was first discovered in 1949 by optical polarization observations. The local magnetic fields within one or two kpc have been well delineated by starlight polarization data. The polarization observations of diffuse Galactic radio background emission in 1962 confirmed unequivocally the existence of a Galactic magnetic field. The bulk of the present information about the magnetic fields in the Galaxy comes from analysis of rotation measures of extragalactic radio sources and pulsars, which can be used to construct the 3-D magnetic field structure in the Galactic halo and Galactic disk. Radio synchrotron spurs in the Galactic center show a poloidal field, and the polarization mapping of dust emission and Zeeman observation in the central molecular zone reveal a toroidal magnetic field parallel to the Galactic plane. For nearby galaxies, both optical polarization and multifrequency radio polarization data clearly show the large-scale magnetic field following the spiral arms or dust lanes. For more distant objects, radio polarization is the only approach available to show the magnetic fields in the jets or lobes of radio galaxies or quasars. Clusters of galaxies also contain widely distributed magnetic fields, which are reflected by radio halos or the RM distribution of background objects. The intergalactic space could have been magnetized by outflows or galactic superwinds even in

  17. Study on the Contribution of the Galactic Cosmic Rays to the Galactic Halo Magnetic Field

    CERN Document Server

    Qu, Xiao-bo; Xue, Liang; Liu, Cheng; Hu, Hong-bo

    2011-01-01

    Based on the measured cosmic ray anisotropy, a model was built to calculate the Galactic cosmic ray's contribution to the large scale Galactic magnetic field. The general agreement in the large scale structure of the Galactic magnetic field between the calculation and the observations is obtained. This result shows that the model is in the right approach in understanding the cosmic ray's contribution to the Galactic magnetic field, and in the mean while, it indicates that the observed anisotropy of cosmic rays on the earth is not just a local behavior in solar vicinity but represents a microcosm of the global anisotropy of the Galactic cosmic rays.

  18. Mapping the exposure of the Brazilian population to natural background radiation - cosmic radiation

    Energy Technology Data Exchange (ETDEWEB)

    Rochedo, Elaine R.R., E-mail: elaine@ird.gov.br [Instituto de Radioprotecao e Dosimetria (lRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Salles, Krause C.S.; Prado, Nadya M.C., E-mail: krausesalles@yahoo.com.br, E-mail: nadya@ime.ib.br [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil)

    2013-07-01

    The main objective of this work is to statically and graphically describe the exposure of the Brazilian population to natural background radiation. in this stage, doses due to cosmic rays is being assessed based on sea level dose rates, corrected by latitude and altitude, according to the model recommended by UNSCEAR. In this work, the doses were estimated for ali Brazilian municipalities with more than 100.000 inhabitants. The 253 municipalities selected for this study include about 52% of the Brazilian population. Average dose rate was estimated to be about 50 n Sv/h with a variation coefficient of 31%. The estimated doses have shown a strong influence of altitude on dose rates, with a correlation coefficient of 0,998 for ao exponential fit. This result confirms previous studies that show a large effect of the altitude 00 exposure from cosmic radiation. Considering the same occupation and shielding conditions used by UNSCEAR as global averages, average annual dose was estimated to be 0,37 (0,24 - 0,76) mSv/y, very close to UNSCEAR worldwide average of 0,38 (0,3 - 1,0) mSv/y. (author)

  19. The source of cosmic radiations; A la source des rayons cosmiques

    Energy Technology Data Exchange (ETDEWEB)

    Letessier-Selvon, A. [Laboratoire de Physique Nucleaire et Hautes Energies, 75 - Paris (France)

    2008-11-15

    The existence of the GZD (Greisen-Zatsepin-Kuzmin) limit comes from the fact that the cosmological diffuse background interacts with cosmological radiations and can reduce dramatically their energy. As a consequence cosmic radiations traveling over large intergalactic distances can not have an energy over 60*10{sup 18} eV (the GZK limit). Another consequence is that a cosmic radiation with an energy greater that the GZK limit comes necessarily from a region no more than 500 million light-years away. The Auger observatory that at term will cover a surface of 3000 km{sup 2} has been designed to study high energy cosmic radiations through the detection of the huge particle showers they trigger when interacting with particles from the upper part of the atmosphere. The first results of the Auger observatory shows three important things. First, the Auger detector's ability to detect is 30 times greater than that of previous experiments. Secondly, 27 events with an energy greater than the GZK limit have been detected and for 20 of them a very active galaxy is located in their incident direction within a distance of 300*10{sup 6} km, these galaxies are then highly suspected to be the source of very high energy cosmic radiations. Thirdly, the graph of the measured cosmic radiation flux shows a brutal drop around 60*10{sup 18} eV which is the GZK limit. (A.C.)

  20. Study of the Intensity Time Variations of the Cosmic Radiation.

    Science.gov (United States)

    different neutron multiplicities at Durham and Mt. Washington, and of the Pioneer 8 cosmic-ray telescope indicated the form of the modulation was different for the 11-year variation and for Forbush decreases during 1968-1970.

  1. Transport of Cosmic Rays in Chaotic Magnetic Fields

    CERN Document Server

    Casse, F; Pelletier, G; Casse, Fabien; Lemoine, Martin; Pelletier, Guy

    2002-01-01

    The transport of charged particles in disorganised magnetic fields is an important issue which concerns the propagation of cosmic rays of all energies in a variety of astrophysical environments, such as the interplanetary, interstellar and even extra-galactic media, as well as the efficiency of Fermi acceleration processes. We have performed detailed numerical experiments using Monte-Carlo simulations of particle propagation in stochastic magnetic fields in order to measure the parallel and transverse spatial diffusion coefficients and the pitch angle scattering time as a function of rigidity and strength of the turbulent magnetic component. We confirm the extrapolation to high turbulence levels of the scaling predicted by the quasi-linear approximation for the scattering frequency and parallel diffusion coefficient at low rigidity. We show that the widely used Bohm diffusion coefficient does not provide a satisfactory approximation to diffusion even in the extreme case where the mean field vanishes. We find ...

  2. A class of effective field theory models of cosmic acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Bloomfield, Jolyon K.; Flanagan, Éanna É., E-mail: jkb84@cornell.edu, E-mail: eef3@cornell.edu [Center for Radiophysics and Space Research, Cornell University, Space Science Building, Ithaca, NY 14853 (United States)

    2012-10-01

    We explore a class of effective field theory models of cosmic acceleration involving a metric and a single scalar field. These models can be obtained by starting with a set of ultralight pseudo-Nambu-Goldstone bosons whose couplings to matter satisfy the weak equivalence principle, assuming that one boson is lighter than all the others, and integrating out the heavier fields. The result is a quintessence model with matter coupling, together with a series of correction terms in the action in a covariant derivative expansion, with specific scalings for the coefficients. After eliminating higher derivative terms and exploiting the field redefinition freedom, we show that the resulting theory contains nine independent free functions of the scalar field when truncated at four derivatives. This is in contrast to the four free functions found in similar theories of single-field inflation, where matter is not present. We discuss several different representations of the theory that can be obtained using the field redefinition freedom. For perturbations to the quintessence field today on subhorizon lengthscales larger than the Compton wavelength of the heavy fields, the theory is weakly coupled and natural in the sense of t'Hooft. The theory admits a regime where the perturbations become modestly nonlinear, but very strong nonlinearities lie outside its domain of validity.

  3. Lower Bound on the Cosmic TeV Gamma-ray Background Radiation

    CERN Document Server

    Inoue, Yoshiyuki

    2015-01-01

    The Fermi gamma-ray space telescope has revolutionized our understanding of the cosmic gamma-ray background radiation in the GeV band. However, investigation on the cosmic TeV gamma-ray background radiation still remains sparse. Here, we report the lower bound on the cosmic TeV gamma-ray background spectrum placed by the cumulative flux of individual detected extragalactic TeV sources including blazars, radio galaxies, and starburst galaxies. The current limit on the cosmic TeV gamma-ray background above 0.1 TeV is obtained as $3\\times10^{-8} (E/100~{\\rm GeV})^{-0.6} \\exp(-E/2000~{\\rm GeV})~{\\rm [GeV/cm^2/s/sr]} < E^2dN/dE < 1\\times10^{-7} (E/100~{\\rm GeV})^{-0.5}~{\\rm [GeV/cm^2/s/sr]}$, where the upper bound is set by requirement that the cascade flux from the cosmic TeV gamma-ray background radiation can not exceed the measured cosmic GeV gamma-ray background spectrum (Inoue & Ioka 2012). Two nearby blazars, Mrk 421 and Mrk 501, explain ~70% of the cumulative flux at 0.8-4 TeV, while extreme blaza...

  4. Cosmological Implications of the Effective Field Theory of Cosmic Acceleration

    CERN Document Server

    Mueller, Eva-Maria; Watson, Scott

    2012-01-01

    We consider cosmological constraints arising from the background expansion history on the ef- fective field theory of cosmic acceleration, a theoretical framework that allows for a unified way to classify both models of dark energy and modified gravity within the linear regime. In the Einstein frame, the most general action for the background can be written in terms of a canonical scalar field which is non-minimally coupled to matter. The leading corrections to the action are expressible through a quartic kinetic term, and scalar couplings to a Gauss-Bonnet curvature term and the Einstein tensor. We determine the implications of the terms in this general action for the predicted expansion history in the context of dynamical attractors. We find that each modifies the matter dominated and/or accelerative eras in ways that allow us to place cosmological constraints on them. We present current constraints on the effective action using the latest Type Ia supernovae, Cosmic Microwave Background, and Baryonic Acoust...

  5. Cosmic Electromagnetic Fields due to Perturbations in the Gravitational Field

    CERN Document Server

    Mongwane, Bishop; Osano, Bob

    2012-01-01

    We use non-linear gauge-invariant perturbation theory to study the interaction of an inflation produced seed magnetic field with density and gravitational wave perturbations in an almost Friedmann-Lema\\^itre-Robertson-Walker (FLRW) spacetime. We compare the effects of this coupling under the assumptions of poor conductivity, infinite conductivity and the case where the electric field is sourced via the coupling of velocity perturbations to the seed field in the ideal magnetohydrodynamic (MHD) regime, thus generalizing, improving on and correcting previous results. We solve our equations for long wavelength limits and numerically integrate the resulting equations to generate power spectra for the electromagnetic field variables, showing where the modes cross the horizon. We find that the rotation of the electric field dominates the power spectrum on small scales, in agreement with previous arguments.

  6. Cosmic rays and radiations from the cosmos; Rayons cosmiques et rayonnement du cosmos

    Energy Technology Data Exchange (ETDEWEB)

    Parizot, E

    2005-12-01

    This document gathers a lot of recent information concerning cosmic radiations, it is divided into 4 parts. Part I: energy, mass and angular spectra of cosmic rays. Part II: general phenomenology of cosmic rays, this part deals with the standard model, the maximal energy of protons inside supernova remnants, nucleosynthesis of light elements, and super-bubbles. Part III: radiations from the cosmos, this part deals with high energy gamma rays, non-thermal radiation of super-bubbles, positron transport, and the Compton trail of gamma-ray bursts. Part IV: the Pierre Auger observatory (OPA), this part deals with the detection of gamma ray bursts at OPA, the measurement of anisotropy, and top-down models. (A.C.)

  7. Acceleration and Particle Field Interactions of Cosmic Rays I: Formalism

    CERN Document Server

    Tawfik, A; Ghoneim, M T; Hady, A A

    2010-01-01

    The acceleration of cosmic rays is conjectured to be the output from various interactions with the electromagnetic fields in astrophysical bodies, like magnetic matter clumps, and from the well-known shock and stochastic Fermi mechanism. The latter apparently does not depend on the particle's charge, quantitatively. Therefore, the motion of the charged particle parallel to magnetic field $\\mathbf{B}$ and under the influence of the force $\\mathbf{F}$. is assumed to be composed in an acceleration by non-magnetic force $\\mathbf{F}_{\\parallel}$ and gyromotion along $\\mathbf{B}$, plus a drift in direction of $\\mathbf{F}_{\\perp}$. In this letter, the model and its formalism are introduced. Also various examples for drift and accelerating forces are studied.

  8. The chemical composition of the cosmic radiation around the ankle and the related spectral indices

    CERN Document Server

    Codino, Antonio

    2009-01-01

    Some recent measurements of the chemical composition of the cosmic radiation indicate that at the energy of 3 x 10 **18 eV, around the ankle, light cosmic ions dominate the spectrum as it occurs in the preknee energy region. Taking advantage of a recent theory of cosmic radiation which provides a quantitative explanation of the knee, the second knee and the ankle, the chemical composition of cosmic radiation is explicitly calculated giving individual ion spectra and ion fractions from 10 ** 12 eV to 5 x 10 ** 19 eV. The calculation assumes two components of the cosmic radiation feeding the ion flux at Earth: one originated in the disc volume and another one, called extradisc component, which from the disc boundaries traverses the Galaxy reaching the solar system. Data above 10 ** 17 eV collected during half century of experimentation by Auger, HiRes, Agasa, Akeno, Fly' s Eye, Yakutsk, Haverah Park and Volcano Ranch experiments are reviewed, examined and compared with the theoretical . The comparison between c...

  9. Modeling of Aircrew Radiation Exposure from Galactic Cosmic Rays and Solar Particle Events

    Science.gov (United States)

    Takada, M.; Lewis, B. J.; Boudreau, M.; Al Anid, H.; Bennett, L. G. I.

    The predictive code for aircrew radiation exposure (PCAIRE) was based on empirical correlations, which were developed from measurement flights during solar cycle 23, for the prediction of the ambient dose equivalent rates. To extend to the extremum conditions of solar modulation and altitude, bounding correlations have been further developed with the LUIN transport code and incorporated into the model. For interpolation between the bounding solar-cycle conditions, the new NASA solar modulation model has been used. The conversion ratio of effective dose to ambient dose equivalent, applied to the (measured) PCAIRE estimate for the legal regulation of aircrew exposure, was re-evaluated in this work to take into consideration the new ICRP-92 radiation weighting factors and different possible irradiation geometries of the source cosmic-radiation field. A computational analysis with MCNPX was used to estimate additional aircrew exposure that may result from sporadic solar particle events, considering the geostationary operational environmental satellite data. These predictions were compared to the ambient dose equivalent rates measured with a TEPC onboard an aircraft prior to and during the event, and were further compared to count rate data observed at various neutron monitors on the ground.

  10. Recent studies on the exposure of aircrew to cosmic and solar radiation

    Energy Technology Data Exchange (ETDEWEB)

    O' Sullivan, D

    2002-07-01

    Investigations of the impact of cosmic and solar radiation on aircrew involve many challenges. The great variety of primary and secondary ionising and non-ionising radiation, the wide range of energies involved and the role played by the Earth's atmosphere and magnetic field and the Sun combine to produce a very complicated scenario. These factors are reflected in conditions on aviation routes where exposure to radiation varies with altitude, latitude and stage of solar cycle. The great increase in air travel and consequent rise in numbers of aircrew whose occupation requires them to work in this environment has prompted new concern about exposure risks at aviation altitudes. The situation has also been highlighted by the tendency for aircraft to fly at higher altitudes in recent years and by the 1990 recommendations of the ICRP that exposure of civil aircrew be considered as being occupational. These have recently been translated into a legal requirement in the European Union. Several studies have been completed using a very wide range of detectors on subsonic and supersonic routes and new investigations are underway. With the completion of the DOSMAX project in another three years or so, world data for a whole solar cycle will be more complete than ever before. Results indicate that for most routes investigated during solar minimum, aircrew are unlikely to receive doses in excess of 6 mSv.yr{sup -1}. (author)

  11. Modelling of aircrew radiation exposure from galactic cosmic rays and solar particle events.

    Science.gov (United States)

    Takada, M; Lewis, B J; Boudreau, M; Al Anid, H; Bennett, L G I

    2007-01-01

    Correlations have been developed for implementation into the semi-empirical Predictive Code for Aircrew Radiation Exposure (PCAIRE) to account for effects of extremum conditions of solar modulation and low altitude based on transport code calculations. An improved solar modulation model, as proposed by NASA, has been further adopted to interpolate between the bounding correlations for solar modulation. The conversion ratio of effective dose to ambient dose equivalent, as applied to the PCAIRE calculation (based on measurements) for the legal regulation of aircrew exposure, was re-evaluated in this work to take into consideration new ICRP-92 radiation-weighting factors and different possible irradiation geometries of the source cosmic-radiation field. A computational analysis with Monte Carlo N-Particle eXtended Code was further used to estimate additional aircrew exposure that may result from sporadic solar energetic particle events considering real-time monitoring by the Geosynchronous Operational Environmental Satellite. These predictions were compared with the ambient dose equivalent rates measured on-board an aircraft and to count rate data observed at various ground-level neutron monitors.

  12. Ageing effects on image sensors due to terrestrial cosmic radiation

    NARCIS (Netherlands)

    Nampoothiri, G.G.; Horemans, M.L.R.; Theuwissen, A.J.P.

    2011-01-01

    We analyze the “ageing” effect on image sensors introduced by neutrons present in natural (terrestrial) cosmic environment. The results obtained at sea level are corroborated for the first time with accelerated neutron beam tests and for various image sensor operation conditions. The results reveal

  13. THE MODULATION OF HEAVY NUCLEI IN THE PRIMARY COSMIC RADIATION,

    Science.gov (United States)

    The ntensities of the primary cosmic ray heavy nuclei, Z equal to or greater than 3, have been studied during several Forbush decreases. Fifteen...observed before, during or after four of the largest Forbush decreases that occurred in the last solar cycle. Examination of this data, together with that

  14. Novel computational approaches for the analysis of cosmic magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Saveliev, Andrey [Universitaet Hamburg, Hamburg (Germany); Keldysh Institut, Moskau (Russian Federation)

    2016-07-01

    In order to give a consistent picture of cosmic, i.e. galactic and extragalactic, magnetic fields, different approaches are possible and often even necessary. Here we present three of them: First, a semianalytic analysis of the time evolution of primordial magnetic fields from which their properties and, subsequently, the nature of present-day intergalactic magnetic fields may be deduced. Second, the use of high-performance computing infrastructure by developing powerful algorithms for (magneto-)hydrodynamic simulations and applying them to astrophysical problems. We are currently developing a code which applies kinetic schemes in massive parallel computing on high performance multiprocessor systems in a new way to calculate both hydro- and electrodynamic quantities. Finally, as a third approach, astroparticle physics might be used as magnetic fields leave imprints of their properties on charged particles transversing them. Here we focus on electromagnetic cascades by developing a software based on CRPropa which simulates the propagation of particles from such cascades through the intergalactic medium in three dimensions. This may in particular be used to obtain information about the helicity of extragalactic magnetic fields.

  15. Dosimetry of cosmic radiation in the troposphere based on the measurements at the summit of Mt. Fuji

    Energy Technology Data Exchange (ETDEWEB)

    Yasuda, H.; Yajima, K.; Yoshida, S. [National Insitute of Radiological Sciences, Chiba (Japan). Research Center for Radiation Protection

    2011-07-01

    Dose rate of cosmic-ray origin neutrons (abbreviated to ''cosmic neutrons'') at aviation altitude was estimated based on the measurements at Mt. Fuji. Cosmic neutrons were measured in a facility of the Mt. Fuji Weather Station located at the summit of Mt. Fuji, the highest mountain in Japan (3776m in altitude), in the summer of 2008 and 2009. The average of 1 cm ambient dose equivalent H*(10) for two measurements was verified by numerical model simulation and then used to empirically estimate the solar force field potential (FFP). The H*(10) rates at aviation altitude estimated from the measurements at Mt. Fuji were compared to those obtained in in-flight measurements onboard a civilian aircraft flying near Mt. Fuji at the time between the two measurements at the mountain. According to the results obtained, we expect that the empirical estimation based on the measurements at Mt. Fuji will work effectively for dosimetry of cosmic radiation in troposphere. (orig.)

  16. Nonlinear evolution of cosmic magnetic fields and cosmic microwave background anisotropies

    Science.gov (United States)

    Tashiro, Hiroyuki; Sugiyama, Naoshi; Banerjee, Robi

    2006-01-01

    In this work we investigate the effects of primordial magnetic fields on cosmic microwave background anisotropies (CMB). Based on cosmological magneto-hydro dynamic (MHD) simulations [R. Banerjee and K. Jedamzik, Phys. Rev. DPRVDAQ0556-2821 70, 123003 (2004).10.1103/PhysRevD.70.123003] we calculate the CMB anisotropy spectra and polarization induced by fluid fluctuations (Alfvén modes) generated by primordial magnetic fields. The strongest effect on the CMB spectra comes from the transition epoch from a turbulent regime to a viscous regime. The balance between magnetic and kinetic energy until the onset of the viscous regime provides a one to one relation between the comoving coherence length L and the comoving magnetic field strength B, such as L˜30(B/10-9Gauss)3pc. The resulting CMB temperature and polarization anisotropies for the initial power law index of the magnetic fields n>3/2 are somewhat different from the ones previously obtained by using linear perturbation theory. In particular, differences can appear on intermediate scales l20000. On scales l0.7Mpc for the most extreme case, or B0.8Mpc for the most conservative case. We may also expect higher signals on large scales of the polarization spectra compared to linear calculations. The signal may even exceed the B-mode polarization from gravitational lensing depending on the strength of the primordial magnetic fields. On very small scales, the diffusion damping scale of nonlinear calculations turns out to be much smaller than the one of linear calculations if the comoving magnetic field strength B>16nGauss. If the magnetic field strength is smaller, the diffusion scales become smaller too. Therefore we expect to have both, temperature and polarization anisotropies, even beyond l>10000 regardless of the strength of the magnetic fields. The peak values of the temperature anisotropy and the B-mode polarization spectra are approximately 40μK and a few μK, respectively.

  17. The Cosmic Background Radiation circa nu2K

    CERN Document Server

    Bond, J R; Prunet, S; Ade, P; Balbi, A; Bock, J J; Borrill, J; Boscaleri, A; Coble, K; Crill, B P; De Bernardis, P; Farese, P; Ferreira, P; Ganga, K; Giacometti, M; Hanany, S; Hivon, E; Hristov, V V; Iacoangeli, A; Jaffe, A; Lange, A; Lee, A; Martinis, L; Masi, S; Mauskopf, P D; Melchiorri, A; Montroy, T; Netterfield, C B; Oh, S; Pascale, E; Piacentini, F; Rabii, B; Rao, S; Richards, P; Romeo, G; Ruhl, J E; Scaramuzzi, F; Sforza, D M; Smoot, G F; Stompor, R; Winant, C; Wu, P

    2000-01-01

    We describe the implications of cosmic microwave background (CMB) observations and galaxy and cluster surveys of large scale structure (LSS) for theories of cosmic structure formation, especially emphasizing the recent Boomerang and Maxima CMB balloon experiments. The inflation-based cosmic structure formation paradigm we have been operating with for two decades has never been in better shape. Here we primarily focus on a simplified inflation parameter set, {omega_b,omega_{cdm},Omega_{tot}, Omega_\\Lambda,n_s,\\tau_C, \\sigma_8}. Combining all of the current CMB+LSS data points to the remarkable conclusion that the local Hubble patch we can access has little mean curvature (Omega_{tot}=1.08\\pm 0.06) and the initial fluctuations were nearly scale invariant (n_s=1.03\\pm 0.08), both predictions of (non-baroque) inflation theory. The baryon density is found to be slightly larger than that preferred by independent Big Bang Nucleosynthesis estimates (omega_b=0.030\\pm 0.005 cf. 0.019\\pm 0.002). The CDM density is in th...

  18. Zero modes on cosmic strings in an external magnetic field

    CERN Document Server

    Ferrer, F; Starkman, G D; Vachaspati, T; Ferrer, Francesc; Mathur, Harsh; Starkman, Glenn D.; Vachaspati, Tanmay

    2006-01-01

    A classical analysis suggests that an external magnetic field can cause trajectories of charge carriers on a superconducting domain wall or cosmic string to bend, thus expelling charge carriers with energy above the mass threshold into the bulk. We study this process by solving the Dirac equation for a fermion of mass $m_f$ and charge $e$, in the background of a domain wall and a magnetic field of strength $B$. We find that the modes of the charge carriers get shifted into the bulk, in agreement with classical expectations. However the dispersion relation for the zero modes changes dramatically -- instead of the usual linear dispersion relation, $\\omega_k =k$, the new dispersion relation is well fit by $\\omega \\approx m_f tanh(k/k_*)$ where $k_*=m_f$ for a thin wall in the weak field limit, and $k_*=eBw$ for a thick wall of width $w$. This result shows that the energy of the charge carriers on the domain wall remains below the threshold for expulsion even in the presence of an external magnetic field. If char...

  19. Further considerations of cosmic ray modulation of infra-red radiation in the atmosphere

    CERN Document Server

    Aplin, Karen

    2015-01-01

    Understanding effects of ionisation in the lower atmosphere is a new interdisciplinary area, crossing traditionally distinct scientific boundaries. Following the paper of Erlykin et al. (Astropart. Phys. 57--58 (2014) 26--29) we develop the interpretation of observed changes in long-wave (LW) radiation (Aplin and Lockwood, Env. Res. Letts. 8, 015026 (2013)), by taking account of cosmic ray ionisation yields and atmospheric radiative transfer. To demonstrate this, we show that the thermal structure of the whole atmosphere needs to be considered along with the vertical profile of ionisation. Allowing for ionisation by all components of a cosmic ray shower and not just by the muons, reveals that the effect we have detected is certainly not inconsistent with laboratory observations of the LW absorption cross section. The analysis presented here, although very different from that of Erlykin et al., does come to the same conclusion that the events detected were not caused by individual cosmic ray primaries -- not b...

  20. Implementing Badhwar-O'Neill Galactic Cosmic Ray Model for the Analysis of Space Radiation Exposure

    Science.gov (United States)

    Kim, Myung-Hee Y.; O'Neill, Patrick M.; Slaba, Tony C.

    2014-01-01

    For the analysis of radiation risks to astronauts and planning exploratory space missions, accurate energy spectrum of galactic cosmic radiation (GCR) is necessary. Characterization of the ionizing radiation environment is challenging because the interplanetary plasma and radiation fields are modulated by solar disturbances and the radiation doses received by astronauts in interplanetary space are likewise influenced. A model of the Badhwar-O'Neill 2011 (BO11) GCR environment, which is represented by GCR deceleration potential theta, has been derived by utilizing all of the GCR measurements from balloons, satellites, and the newer NASA Advanced Composition Explorer (ACE). In the BO11 model, the solar modulation level is derived from the mean international sunspot numbers with time-delay, which has been calibrated with actual flight instrument measurements to produce better GCR flux data fit during solar minima. GCR fluxes provided by the BO11 model were compared with various spacecraft measurements at 1 AU, and further comparisons were made for the tissue equivalent proportional counters measurements at low Earth orbits using the high-charge and energy transport (HZETRN) code and various GCR models. For the comparison of the absorbed dose and dose equivalent calculations with the measurements by Radiation Assessment Detector (RAD) at Gale crater on Mars, the intensities and energies of GCR entering the heliosphere were calculated by using the BO11 model, which accounts for time-dependent attenuation of the local interstellar spectrum of each element. The BO11 model, which has emphasized for the last 24 solar minima, showed in relatively good agreement with the RAD data for the first 200 sols, but it was resulted in to be less well during near the solar maximum of solar cycle 24 due to subtleties in the changing heliospheric conditions. By performing the error analysis of the BO11 model and the optimization in reducing overall uncertainty, the resultant BO13 model

  1. Noncommutative double scalar fields in FRW cosmology as cosmical oscillators

    Energy Technology Data Exchange (ETDEWEB)

    Malekolkalami, Behrooz; Farhoudi, Mehrdad, E-mail: b_malekolkalami@sbu.ac.i, E-mail: m-farhoudi@sbu.ac.i [Department of Physics, Shahid Beheshti University, G.C., Evin, Tehran 19839 (Iran, Islamic Republic of)

    2010-12-21

    We investigate the effects caused by noncommutativity of the phase space generated by two scalar fields that have non-minimal conformal couplings to the background curvature in the FRW cosmology. We restrict deformation of the minisuperspace to noncommutativity between the scalar fields and between their canonical conjugate momenta. Then, the investigation is carried out by means of a comparative analysis of the mathematical properties (supplemented with some diagrams) of the time evolution of variables in a classical model and the wavefunction of the universe in a quantum perspective, both in the commutative and noncommutative frames. We find that the imposition of noncommutativity causes more ability in tuning time solutions of the scalar fields and, hence, has important implications in the evolution of the Universe. We find that the noncommutative parameter in the momenta sector is the only responsible parameter for the noncommutative effects in the spatially flat universes. A distinguishing feature of the noncommutative solutions of the scalar fields is that they can be simulated with the well-known three harmonic oscillators depending on three values of the spatial curvature, namely the free, forced and damped harmonic oscillators corresponding to the flat, closed and open universes, respectively. In this respect, we call them cosmical oscillators. In particular, in closed universes, when the noncommutative parameters are small, the cosmical oscillators have an analogous effect with the familiar beating effect in the sound phenomena. Some of the special solutions in the classical model and the allowed wavefunctions in the quantum model make bounds on the values of the noncommutative parameters. The existence of a non-zero constant potential (i.e. a cosmological constant) does not change time evolutions of the scalar fields, but modifies the scale factor. An interesting feature of the well-behaved solutions of the wavefunctions is that the functional form of

  2. Measurement of the cosmic background radiation temperature at 6. 3 cm

    Energy Technology Data Exchange (ETDEWEB)

    Mandolesi, N.; Calzolari, P.; Cortiglioni, S.; Morigi, G.

    1984-06-15

    We present results of a measurement of the cosmic background radiation temperature at a wavelength of 6.3 cm. We obtained the value T/sub CBR/ = 2.71 +- 0.20 K. This is in good agreement with, and has a smaller error than, any previous measurement at equal or longer wavelengths.

  3. Cosmic radiation in aviation: radiological protection of Air France aircraft crew.

    Science.gov (United States)

    Desmaris, G

    2016-06-01

    Cosmic radiation in aviation has been a concern since the 1960s, and measurements have been taken for several decades by Air France. Results show that aircraft crew generally receive 3-4 mSv y(-1) for 750 boarding hours. Compliance with the trigger level of 6 mSv y(-1) is achieved by route selection. Work schedules can be developed for pregnant pilots to enable the dose to the fetus to be kept below 1 mSv. Crew members are informed of their exposition and the potential health impact. The upcoming International Commission on Radiological Protection (ICRP) report on cosmic radiation in aviation will provide an updated guidance. A graded approach proportionate with the time of exposure is recommended to implement the optimisation principle. The objective is to keep exposures of the most exposed aircraft members to reasonable levels. ICRP also recommends that information about cosmic radiation be disseminated, and that awareness about cosmic radiation be raised in order to favour informed decision-making by all concerned stakeholders.

  4. Cosmic radiation during air travel: trends in exposure of aircrews and airline passengers

    NARCIS (Netherlands)

    Blaauboer RO; LSO

    2004-01-01

    An unfavourable effect of flying is the enhanced exposure of both passengers and aircrew to cosmic radiation at high altitudes. On the basis of a detailed survey on passengers arriving at or departing from Amsterdam Schiphol Airport in the 1988-1997 period, estimates of individual effective dose for

  5. Cosmic microwave background bispectrum of tensor passive modes induced from primordial magnetic fields

    CERN Document Server

    Shiraishi, Maresuke; Yokoyama, Shuichiro; Ichiki, Kiyotomo; Takahashi, Keitaro

    2011-01-01

    If the seed magnetic fields exist in the early Universe, tensor components of their anisotropic stresses are not compensated prior to neutrino decoupling and the tensor metric perturbations generated from them survive passively. Consequently, due to the decay of these metric perturbations after recombination, so-called, integrated Sachs-Wolfe effect, the large-scale fluctuations of the cosmic microwave background (CMB) radiation are significantly boosted. This kind of the CMB anisotropy is called "tensor passive mode". Because these fluctuations deviate largely from the Gaussian statistics due to the quadratic dependence on the strength of the Gaussian magnetic field, not only the power spectrum but also the higher-order correlations have reasonable signals. With these motives, we compute the CMB bispectrum induced by this mode. When the magnetic spectrum obeys a nearly scale-invariant shape, we obtain an estimation of a typical value of the normalized reduced bispectrum as $\\ell_1(\\ell_1 + 1)\\ell_3(\\ell_3+1)...

  6. The large-scale properties of simulated cosmic magnetic fields

    CERN Document Server

    Marinacci, Federico; Mocz, Philip; Pakmor, Ruediger

    2015-01-01

    We perform uniformly sampled large-scale cosmological simulations including magnetic fields with the moving mesh code AREPO. We run two sets of MHD simulations: one including adiabatic gas physics only; the other featuring the fiducial feedback model of the Illustris simulation. In the adiabatic case, the magnetic field amplification follows the $B \\propto \\rho^{2/3}$ scaling derived from `flux-freezing' arguments, with the seed field strength providing an overall normalisation factor. At high baryon overdensities the amplification is enhanced by shear flows and turbulence. Feedback physics and the inclusion of radiative cooling change this picture dramatically. Gas collapses to much larger densities and the magnetic field is amplified strongly, reaching saturation and losing memory of the initial seed field. At lower densities a dependence on the seed field strength and orientation, which in principle can be used to constrain models of cosmological magnetogenesis, is still present. Inside the most massive ha...

  7. The cosmic background radiation circa {nu}2K

    Energy Technology Data Exchange (ETDEWEB)

    Bond, J. Richard; Pogosyan, Dmitry; Prunet, Simon

    2000-01-01

    We describe the implications of cosmic microwave background (CMB) observations and galaxy and cluster surveys of large scale structure (LSS) for theories of cosmic structure formation, especially emphasizing the recent Boomerang and Maxima CMB balloon experiments. The inflation-based cosmic structure formation paradigm we have been operating with for two decades has never been in better shape. Here we primarily focus on a simplified inflation parameter set, {l_brace}{omega}{sub b}, {omega}{sub cdm}, {omega}{sub tot}, {omega}{sub {lambda}}, n{sub s}, {tau}{sub C}, {sigma}{sub 8}{r_brace}. Combining all of the current CMB+LSS data points to the remarkable conclusion that the local Hubble patch we can access has little mean curvature ({omega}{sub tot} = 1.08 {+-} 0.06) and the initial fluctuations were nearly scale invariant (n{sub s} 1.03 {+-} 0.08), both predictions of (non-baroque) inflation theory. The baryon density is found to be slightly larger than that preferred by independent Big Bang Nucleosynthesis estimates ({omega}{sub b}-{omega}{sub b}h{sup 2} 0.030 {+-} 0.005 cf. 0.019 {+-} 0.002). The CDM density is in the expected range ({omega}{sub cdm} 0.17{+-}0.02). Even stranger is the CMB+LSS evidence that the density of the universe is dominated by unclustered energy akin to the cosmological constant ({omega}{sub {lambda}} = 0.66 {+-} 0.06), at the same level as that inferred from high redshift supernova observations. We also sketch the CMB+LSS implications for massive neutrinos.

  8. Radiation -- A Cosmic Hazard to Human Habitation in Space

    Science.gov (United States)

    Lewis, Ruthan; Pellish, Jonathan

    2017-01-01

    Radiation exposure is one of the greatest environmental threats to the performance and success of human and robotic space missions. Radiation permeates all space and aeronautical systems, challenges optimal and reliable performance, and tests survival and survivability. We will discuss the broad scope of research, technological, and operational considerations to forecast and mitigate the effects of the radiation environment for deep space and planetary exploration.

  9. Dark energy and the cosmic microwave background radiation

    Science.gov (United States)

    Dodelson, S.; Knox, L.

    2000-01-01

    We find that current cosmic microwave background anisotropy data strongly constrain the mean spatial curvature of the Universe to be near zero, or, equivalently, the total energy density to be near critical-as predicted by inflation. This result is robust to editing of data sets, and variation of other cosmological parameters (totaling seven, including a cosmological constant). Other lines of argument indicate that the energy density of nonrelativistic matter is much less than critical. Together, these results are evidence, independent of supernovae data, for dark energy in the Universe.

  10. Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy

    CERN Document Server

    Aab, Alexander; Aglietta, Marco; Ahn, Eun-Joo; Samarai, Imen Al; Albuquerque, Ivone; Allekotte, Ingomar; Allison, Patrick; Almela, Alejandro; Castillo, Jesus Alvarez; Alvarez-Muñiz, Jaime; Batista, Rafael Alves; Ambrosio, Michelangelo; Aminaei, Amin; Anastasi, Gioacchino Alex; Anchordoqui, Luis; Andringa, Sofia; Aramo, Carla; Arqueros, Fernando; Arsene, Nicusor; Asorey, Hernán Gonzalo; Assis, Pedro; Aublin, Julien; Avila, Gualberto; Awal, Nafiun; Badescu, Alina Mihaela; Baus, Colin; Beatty, Jim; Becker, Karl Heinz; Bellido, Jose A; Berat, Corinne; Bertaina, Mario Edoardo; Bertou, Xavier; Biermann, Peter; Billoir, Pierre; Blaess, Simon G; Blanco, Alberto; Blanco, Miguel; Blazek, Jiri; Bleve, Carla; Blümer, Hans; Boháčová, Martina; Boncioli, Denise; Bonifazi, Carla; Borodai, Nataliia; Brack, Jeffrey; Brancus, Iliana; Bretz, Thomas; Bridgeman, Ariel; Brogueira, Pedro; Buchholz, Peter; Bueno, Antonio; Buitink, Stijn; Buscemi, Mario; Caballero-Mora, Karen S; Caccianiga, Barbara; Caccianiga, Lorenzo; Candusso, Marina; Caramete, Laurentiu; Caruso, Rossella; Castellina, Antonella; Cataldi, Gabriella; Cazon, Lorenzo; Cester, Rosanna; Chavez, Alan G; Chiavassa, Andrea; Chinellato, Jose Augusto; Chudoba, Jiri; Cilmo, Marco; Clay, Roger W; Cocciolo, Giuseppe; Colalillo, Roberta; Coleman, Alan; Collica, Laura; Coluccia, Maria Rita; Conceição, Ruben; Contreras, Fernando; Cooper, Mathew J; Cordier, Alain; Coutu, Stephane; Covault, Corbin; Cronin, James; Dallier, Richard; Daniel, Bruno; Dasso, Sergio; Daumiller, Kai; Dawson, Bruce R; de Almeida, Rogerio M; de Jong, Sijbrand J; De Mauro, Giuseppe; Neto, Joao de Mello; De Mitri, Ivan; de Oliveira, Jaime; de Souza, Vitor; del Peral, Luis; Deligny, Olivier; Dhital, Niraj; Di Giulio, Claudio; Di Matteo, Armando; Diaz, Johana Chirinos; Castro, Mary Lucia Díaz; Diogo, Francisco; Dobrigkeit, Carola; Docters, Wendy; D'Olivo, Juan Carlos; Dorofeev, Alexei; Hasankiadeh, Qader Dorosti; Anjos, Rita dos; Dova, Maria Teresa; Ebr, Jan; Engel, Ralph; Erdmann, Martin; Erfani, Mona; Escobar, Carlos O; Espadanal, Joao; Etchegoyen, Alberto; Falcke, Heino; Fang, Ke; Farrar, Glennys; Fauth, Anderson; Fazzini, Norberto; Ferguson, Andrew P; Fick, Brian; Figueira, Juan Manuel; Filevich, Alberto; Filipčič, Andrej; Fratu, Octavian; Freire, Martín Miguel; Fujii, Toshihiro; García, Beatriz; Garcia-Gamez, Diego; Garcia-Pinto, Diego; Gate, Florian; Gemmeke, Hartmut; Gherghel-Lascu, Alexandru; Ghia, Piera Luisa; Giaccari, Ugo; Giammarchi, Marco; Giller, Maria; Głas, Dariusz; Glaser, Christian; Glass, Henry; Golup, Geraldina; Berisso, Mariano Gómez; Vitale, Primo F Gómez; González, Nicolás; Gookin, Ben; Gordon, Jacob; Gorgi, Alessio; Gorham, Peter; Gouffon, Philippe; Griffith, Nathan; Grillo, Aurelio; Grubb, Trent D; Guarino, Fausto; Guedes, Germano; Hampel, Matías Rolf; Hansen, Patricia; Harari, Diego; Harrison, Thomas A; Hartmann, Sebastian; Harton, John; Haungs, Andreas; Hebbeker, Thomas; Heck, Dieter; Heimann, Philipp; Herve, Alexander E; Hill, Gary C; Hojvat, Carlos; Hollon, Nicholas; Holt, Ewa; Homola, Piotr; Hörandel, Jörg; Horvath, Pavel; Hrabovský, Miroslav; Huber, Daniel; Huege, Tim; Insolia, Antonio; Isar, Paula Gina; Jandt, Ingolf; Jansen, Stefan; Jarne, Cecilia; Johnsen, Jeffrey A; Josebachuili, Mariela; Kääpä, Alex; Kambeitz, Olga; Kampert, Karl Heinz; Kasper, Peter; Katkov, Igor; Keilhauer, Bianca; Kemp, Ernesto; Kieckhafer, Roger; Klages, Hans; Kleifges, Matthias; Kleinfeller, Jonny; Krause, Raphael; Krohm, Nicole; Kuempel, Daniel; Mezek, Gasper Kukec; Kunka, Norbert; Awad, Alaa Metwaly Kuotb; LaHurd, Danielle; Latronico, Luca; Lauer, Robert; Lauscher, Markus; Lautridou, Pascal; Coz, Sandra Le; Lebrun, Didier; Lebrun, Paul; de Oliveira, Marcelo Augusto Leigui; Letessier-Selvon, Antoine; Lhenry-Yvon, Isabelle; Link, Katrin; Lopes, Luis; López, Rebeca; Casado, Aida López; Louedec, Karim; Lucero, Agustin; Malacari, Max; Mallamaci, Manuela; Maller, Jennifer; Mandat, Dusan; Mantsch, Paul; Mariazzi, Analisa; Marin, Vincent; Mariş, Ioana; Marsella, Giovanni; Martello, Daniele; Martinez, Humberto; Bravo, Oscar Martínez; Martraire, Diane; Meza, Jimmy Masías; Mathes, Hermann-Josef; Mathys, Sebastian; Matthews, James; Matthews, John; Matthiae, Giorgio; Maurizio, Daniela; Mayotte, Eric; Mazur, Peter; Medina, Carlos; Medina-Tanco, Gustavo; Meissner, Rebecca; Mello, Victor; Melo, Diego; Menshikov, Alexander; Messina, Stefano; Micheletti, Maria Isabel; Middendorf, Lukas; Minaya, Ignacio A; Miramonti, Lino; Mitrica, Bogdan; Molina-Bueno, Laura; Mollerach, Silvia; Montanet, François; Morello, Carlo; Mostafá, Miguel; Moura, Celio A; Muller, Marcio Aparecido; Müller, Gero; Müller, Sarah; Navas, Sergio; Necesal, Petr; Nellen, Lukas; Nelles, Anna; Neuser, Jens; Nguyen, Phong H; Niculescu-Oglinzanu, Mihai; Niechciol, Marcus; Niemietz, Lukas; Niggemann, Tim; Nitz, Dave; Nosek, Dalibor; Novotny, Vladimir; Nožka, Lyberis; Núñez, Luis; Ochilo, Livingstone; Oikonomou, Foteini; Olinto, Angela; Pacheco, Noelia; Selmi-Dei, Daniel Pakk; Palatka, Miroslav; Pallotta, Juan; Papenbreer, Philipp; Parente, Gonzalo; Parra, Alejandra; Paul, Thomas; Pech, Miroslav; Pękala, Jan; Pelayo, Rodrigo; Pepe, Iuri; Perrone, Lorenzo; Petermann, Emily; Peters, Christine; Petrera, Sergio; Petrov, Yevgeniy; Phuntsok, Jamyang; Piegaia, Ricardo; Pierog, Tanguy; Pieroni, Pablo; Pimenta, Mário; Pirronello, Valerio; Platino, Manuel; Plum, Matthias; Porcelli, Alessio; Porowski, Czeslaw; Prado, Raul Ribeiro; Privitera, Paolo; Prouza, Michael; Quel, Eduardo J; Querchfeld, Sven; Quinn, Sean; Rautenberg, Julian; Ravel, Olivier; Ravignani, Diego; Reinert, Darius; Revenu, Benoît; Ridky, Jan; Risse, Markus; Ristori, Pablo; Rizi, Vincenzo; de Carvalho, Washington Rodrigues; Rojo, Jorge Rubén Rodriguez; Rodríguez-Frías, Maria Dolores; Rogozin, Dmytro; Rosado, Jaime; Roth, Markus; Roulet, Esteban; Rovero, Adrian; Saffi, Steven J; Saftoiu, Alexandra; Salazar, Humberto; Saleh, Ahmed; Greus, Francisco Salesa; Salina, Gaetano; Gomez, Jose Sanabria; Sánchez, Federico; Sanchez-Lucas, Patricia; Santos, Edivaldo Moura; Santos, Eva; Sarazin, Fred; Sarkar, Biswaijt; Sarmento, Raul; Sarmiento-Cano, Christian; Sato, Ricardo; Scarso, Carlos; Schauer, Markus; Scherini, Viviana; Schieler, Harald; Schmidt, David; Scholten, Olaf; Schoorlemmer, Harm; Schovánek, Petr; Schröder, Frank G; Schulz, Alexander; Schulz, Johannes; Schumacher, Johannes; Sciutto, Sergio; Segreto, Alberto; Settimo, Mariangela; Shadkam, Amir; Shellard, Ronald C; Sigl, Guenter; Sima, Octavian; Śmiałkowski, Andrzej; Šmída, Radomir; Snow, Gregory; Sommers, Paul; Sonntag, Sebastian; Sorokin, J; Squartini, Ruben; Srivastava, Yogendra N; Stanca, Denis; Stanič, Samo; Stapleton, James; Stasielak, Jaroslaw; Stephan, Maurice; Stutz, Anne; Suarez, Federico; Durán, Mauricio Suarez; Suomijärvi, Tiina; Supanitsky, A Daniel; Sutherland, Michael; Swain, John; Szadkowski, Zbigniew; Taborda, Oscar Alejandro; Tapia, Alex; Tepe, Andreas; Theodoro, Vanessa Menezes; Timmermans, Charles; Peixoto, Carlos J Todero; Toma, Gabriel; Tomankova, Lenka; Tomé, Bernardo; Tonachini, Aurelio; Elipe, Guillermo Torralba; Machado, Diego Torres; Travnicek, Petr; Trini, Marta; Ulrich, Ralf; Unger, Michael; Urban, Martin; Galicia, Jose F Valdés; Valiño, Ines; Valore, Laura; van Aar, Guus; van Bodegom, Patrick; Berg, Ad M van den; van Velzen, Sjoert; van Vliet, Arjen; Varela, Enrique; Cárdenas, Bernardo Vargas; Varner, Gary; Vasquez, Rafael; Vázquez, Jose R; Vázquez, Ricardo; Veberič, Darko; Verzi, Valerio; Vicha, Jakub; Videla, Mariela; Villaseñor, Luis; Vlcek, Brian; Vorobiov, Serguei; Wahlberg, Hernan; Wainberg, Oscar; Walz, David; Watson, Alan; Weber, Marc; Weidenhaupt, Klaus; Weindl, Andreas; Welling, Christoph; Werner, Felix; Widom, Allan; Wiencke, Lawrence; Wilczyński, Henryk; Winchen, Tobias; Wittkowski, David; Wundheiler, Brian; Wykes, Sarka; Yang, Lili; Yapici, Tolga; Yushkov, Alexey; Zas, Enrique; Zavrtanik, Danilo; Zavrtanik, Marko; Zepeda, Arnulfo; Zimmermann, Benedikt; Ziolkowski, Michael; Zuccarello, Francesca

    2016-01-01

    We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8 \\pm 0.7 (stat) \\pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principle calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the direct calibration of any cosmic-ray radio detector against the well-established energy scale of the Pierre Auger Observatory.

  11. Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy.

    Science.gov (United States)

    Aab, A; Abreu, P; Aglietta, M; Ahn, E J; Al Samarai, I; Albuquerque, I F M; Allekotte, I; Allison, P; Almela, A; Alvarez Castillo, J; Alvarez-Muñiz, J; Alves Batista, R; Ambrosio, M; Aminaei, A; Anastasi, G A; Anchordoqui, L; Andringa, S; Aramo, C; Arqueros, F; Arsene, N; Asorey, H; Assis, P; Aublin, J; Avila, G; Awal, N; Badescu, A M; Baus, C; Beatty, J J; Becker, K H; Bellido, J A; Berat, C; Bertaina, M E; Bertou, X; Biermann, P L; Billoir, P; Blaess, S G; Blanco, A; Blanco, M; Blazek, J; Bleve, C; Blümer, H; Boháčová, M; Boncioli, D; Bonifazi, C; Borodai, N; Brack, J; Brancus, I; Bretz, T; Bridgeman, A; Brogueira, P; Buchholz, P; Bueno, A; Buitink, S; Buscemi, M; Caballero-Mora, K S; Caccianiga, B; Caccianiga, L; Candusso, M; Caramete, L; Caruso, R; Castellina, A; Cataldi, G; Cazon, L; Cester, R; Chavez, A G; Chiavassa, A; Chinellato, J A; Chudoba, J; Cilmo, M; Clay, R W; Cocciolo, G; Colalillo, R; Coleman, A; Collica, L; Coluccia, M R; Conceição, R; Contreras, F; Cooper, M J; Cordier, A; Coutu, S; Covault, C E; Cronin, J; Dallier, R; Daniel, B; Dasso, S; Daumiller, K; Dawson, B R; de Almeida, R M; de Jong, S J; De Mauro, G; de Mello Neto, J R T; De Mitri, I; de Oliveira, J; de Souza, V; Del Peral, L; Deligny, O; Dhital, N; Di Giulio, C; Di Matteo, A; Diaz, J C; Díaz Castro, M L; Diogo, F; Dobrigkeit, C; Docters, W; D'Olivo, J C; Dorofeev, A; Dorosti Hasankiadeh, Q; Dos Anjos, R C; Dova, M T; Ebr, J; Engel, R; Erdmann, M; Erfani, M; Escobar, C O; Espadanal, J; Etchegoyen, A; Falcke, H; Fang, K; Farrar, G; Fauth, A C; Fazzini, N; Ferguson, A P; Fick, B; Figueira, J M; Filevich, A; Filipčič, A; Fratu, O; Freire, M M; Fujii, T; García, B; Garcia-Gamez, D; Garcia-Pinto, D; Gate, F; Gemmeke, H; Gherghel-Lascu, A; Ghia, P L; Giaccari, U; Giammarchi, M; Giller, M; Głas, D; Glaser, C; Glass, H; Golup, G; Gómez Berisso, M; Gómez Vitale, P F; González, N; Gookin, B; Gordon, J; Gorgi, A; Gorham, P; Gouffon, P; Griffith, N; Grillo, A F; Grubb, T D; Guarino, F; Guedes, G P; Hampel, M R; Hansen, P; Harari, D; Harrison, T A; Hartmann, S; Harton, J L; Haungs, A; Hebbeker, T; Heck, D; Heimann, P; Herve, A E; Hill, G C; Hojvat, C; Hollon, N; Holt, E; Homola, P; Hörandel, J R; Horvath, P; Hrabovský, M; Huber, D; Huege, T; Insolia, A; Isar, P G; Jandt, I; Jansen, S; Jarne, C; Johnsen, J A; Josebachuili, M; Kääpä, A; Kambeitz, O; Kampert, K H; Kasper, P; Katkov, I; Keilhauer, B; Kemp, E; Kieckhafer, R M; Klages, H O; Kleifges, M; Kleinfeller, J; Krause, R; Krohm, N; Kuempel, D; Kukec Mezek, G; Kunka, N; Kuotb Awad, A W; LaHurd, D; Latronico, L; Lauer, R; Lauscher, M; Lautridou, P; Le Coz, S; Lebrun, D; Lebrun, P; Leigui de Oliveira, M A; Letessier-Selvon, A; Lhenry-Yvon, I; Link, K; Lopes, L; López, R; López Casado, A; Louedec, K; Lucero, A; Malacari, M; Mallamaci, M; Maller, J; Mandat, D; Mantsch, P; Mariazzi, A G; Marin, V; Mariş, I C; Marsella, G; Martello, D; Martinez, H; Martínez Bravo, O; Martraire, D; Masías Meza, J J; Mathes, H J; Mathys, S; Matthews, J; Matthews, J A J; Matthiae, G; Maurizio, D; Mayotte, E; Mazur, P O; Medina, C; Medina-Tanco, G; Meissner, R; Mello, V B B; Melo, D; Menshikov, A; Messina, S; Micheletti, M I; Middendorf, L; Minaya, I A; Miramonti, L; Mitrica, B; Molina-Bueno, L; Mollerach, S; Montanet, F; Morello, C; Mostafá, M; Moura, C A; Muller, M A; Müller, G; Müller, S; Navas, S; Necesal, P; Nellen, L; Nelles, A; Neuser, J; Nguyen, P H; Niculescu-Oglinzanu, M; Niechciol, M; Niemietz, L; Niggemann, T; Nitz, D; Nosek, D; Novotny, V; Nožka, L; Núñez, L A; Ochilo, L; Oikonomou, F; Olinto, A; Pacheco, N; Pakk Selmi-Dei, D; Palatka, M; Pallotta, J; Papenbreer, P; Parente, G; Parra, A; Paul, T; Pech, M; Pȩkala, J; Pelayo, R; Pepe, I M; Perrone, L; Petermann, E; Peters, C; Petrera, S; Petrov, Y; Phuntsok, J; Piegaia, R; Pierog, T; Pieroni, P; Pimenta, M; Pirronello, V; Platino, M; Plum, M; Porcelli, A; Porowski, C; Prado, R R; Privitera, P; Prouza, M; Quel, E J; Querchfeld, S; Quinn, S; Rautenberg, J; Ravel, O; Ravignani, D; Reinert, D; Revenu, B; Ridky, J; Risse, M; Ristori, P; Rizi, V; Rodrigues de Carvalho, W; Rodriguez Rojo, J; Rodríguez-Frías, M D; Rogozin, D; Rosado, J; Roth, M; Roulet, E; Rovero, A C; Saffi, S J; Saftoiu, A; Salazar, H; Saleh, A; Salesa Greus, F; Salina, G; Sanabria Gomez, J D; Sánchez, F; Sanchez-Lucas, P; Santos, E; Santos, E M; Sarazin, F; Sarkar, B; Sarmento, R; Sarmiento-Cano, C; Sato, R; Scarso, C; Schauer, M; Scherini, V; Schieler, H; Schmidt, D; Scholten, O; Schoorlemmer, H; Schovánek, P; Schröder, F G; Schulz, A; Schulz, J; Schumacher, J; Sciutto, S J; Segreto, A; Settimo, M; Shadkam, A; Shellard, R C; Sigl, G; Sima, O; Śmiałkowski, A; Šmída, R; Snow, G R; Sommers, P; Sonntag, S; Sorokin, J; Squartini, R; Srivastava, Y N; Stanca, D; Stanič, S; Stapleton, J; Stasielak, J; Stephan, M; Stutz, A; Suarez, F; Suarez Durán, M; Suomijärvi, T; Supanitsky, A D; Sutherland, M S; Swain, J; Szadkowski, Z; Taborda, O A; Tapia, A; Tepe, A; Theodoro, V M; Timmermans, C; Todero Peixoto, C J; Toma, G; Tomankova, L; Tomé, B; Tonachini, A; Torralba Elipe, G; Torres Machado, D; Travnicek, P; Trini, M; Ulrich, R; Unger, M; Urban, M; Valdés Galicia, J F; Valiño, I; Valore, L; van Aar, G; van Bodegom, P; van den Berg, A M; van Velzen, S; van Vliet, A; Varela, E; Vargas Cárdenas, B; Varner, G; Vasquez, R; Vázquez, J R; Vázquez, R A; Veberič, D; Verzi, V; Vicha, J; Videla, M; Villaseñor, L; Vlcek, B; Vorobiov, S; Wahlberg, H; Wainberg, O; Walz, D; Watson, A A; Weber, M; Weidenhaupt, K; Weindl, A; Welling, C; Werner, F; Widom, A; Wiencke, L; Wilczyński, H; Winchen, T; Wittkowski, D; Wundheiler, B; Wykes, S; Yang, L; Yapici, T; Yushkov, A; Zas, E; Zavrtanik, D; Zavrtanik, M; Zepeda, A; Zimmermann, B; Ziolkowski, M; Zuccarello, F

    2016-06-17

    We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8±0.7(stat)±6.7(syst)  MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principles calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the direct calibration of any cosmic-ray radio detector against the well-established energy scale of the Pierre Auger Observatory.

  12. Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy

    Science.gov (United States)

    Aab, A.; Abreu, P.; Aglietta, M.; Ahn, E. J.; Al Samarai, I.; Albuquerque, I. F. M.; Allekotte, I.; Allison, P.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muñiz, J.; Alves Batista, R.; Ambrosio, M.; Aminaei, A.; Anastasi, G. A.; Anchordoqui, L.; Andringa, S.; Aramo, C.; Arqueros, F.; Arsene, N.; Asorey, H.; Assis, P.; Aublin, J.; Avila, G.; Awal, N.; Badescu, A. M.; Baus, C.; Beatty, J. J.; Becker, K. H.; Bellido, J. A.; Berat, C.; Bertaina, M. E.; Bertou, X.; Biermann, P. L.; Billoir, P.; Blaess, S. G.; Blanco, A.; Blanco, M.; Blazek, J.; Bleve, C.; Blümer, H.; Boháčová, M.; Boncioli, D.; Bonifazi, C.; Borodai, N.; Brack, J.; Brancus, I.; Bretz, T.; Bridgeman, A.; Brogueira, P.; Buchholz, P.; Bueno, A.; Buitink, S.; Buscemi, M.; Caballero-Mora, K. S.; Caccianiga, B.; Caccianiga, L.; Candusso, M.; Caramete, L.; Caruso, R.; Castellina, A.; Cataldi, G.; Cazon, L.; Cester, R.; Chavez, A. G.; Chiavassa, A.; Chinellato, J. A.; Chudoba, J.; Cilmo, M.; Clay, R. W.; Cocciolo, G.; Colalillo, R.; Coleman, A.; Collica, L.; Coluccia, M. R.; Conceição, R.; Contreras, F.; Cooper, M. J.; Cordier, A.; Coutu, S.; Covault, C. E.; Cronin, J.; Dallier, R.; Daniel, B.; Dasso, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; de Jong, S. J.; De Mauro, G.; de Mello Neto, J. R. T.; De Mitri, I.; de Oliveira, J.; de Souza, V.; del Peral, L.; Deligny, O.; Dhital, N.; Di Giulio, C.; Di Matteo, A.; Diaz, J. C.; Díaz Castro, M. L.; Diogo, F.; Dobrigkeit, C.; Docters, W.; D'Olivo, J. C.; Dorofeev, A.; Dorosti Hasankiadeh, Q.; dos Anjos, R. C.; Dova, M. T.; Ebr, J.; Engel, R.; Erdmann, M.; Erfani, M.; Escobar, C. O.; Espadanal, J.; Etchegoyen, A.; Falcke, H.; Fang, K.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Ferguson, A. P.; Fick, B.; Figueira, J. M.; Filevich, A.; Filipčič, A.; Fratu, O.; Freire, M. M.; Fujii, T.; García, B.; Garcia-Gamez, D.; Garcia-Pinto, D.; Gate, F.; Gemmeke, H.; Gherghel-Lascu, A.; Ghia, P. L.; Giaccari, U.; Giammarchi, M.; Giller, M.; Głas, D.; Glaser, C.; Glass, H.; Golup, G.; Gómez Berisso, M.; Gómez Vitale, P. F.; González, N.; Gookin, B.; Gordon, J.; Gorgi, A.; Gorham, P.; Gouffon, P.; Griffith, N.; Grillo, A. F.; Grubb, T. D.; Guarino, F.; Guedes, G. P.; Hampel, M. R.; Hansen, P.; Harari, D.; Harrison, T. A.; Hartmann, S.; Harton, J. L.; Haungs, A.; Hebbeker, T.; Heck, D.; Heimann, P.; Herve, A. E.; Hill, G. C.; Hojvat, C.; Hollon, N.; Holt, E.; Homola, P.; Hörandel, J. R.; Horvath, P.; Hrabovský, M.; Huber, D.; Huege, T.; Insolia, A.; Isar, P. G.; Jandt, I.; Jansen, S.; Jarne, C.; Johnsen, J. A.; Josebachuili, M.; Kääpä, A.; Kambeitz, O.; Kampert, K. H.; Kasper, P.; Katkov, I.; Keilhauer, B.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Krause, R.; Krohm, N.; Kuempel, D.; Kukec Mezek, G.; Kunka, N.; Kuotb Awad, A. W.; LaHurd, D.; Latronico, L.; Lauer, R.; Lauscher, M.; Lautridou, P.; Le Coz, S.; Lebrun, D.; Lebrun, P.; Leigui de Oliveira, M. A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; Link, K.; Lopes, L.; López, R.; López Casado, A.; Louedec, K.; Lucero, A.; Malacari, M.; Mallamaci, M.; Maller, J.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Marin, V.; Mariş, I. C.; Marsella, G.; Martello, D.; Martinez, H.; Martínez Bravo, O.; Martraire, D.; Masías Meza, J. J.; Mathes, H. J.; Mathys, S.; Matthews, J.; Matthews, J. A. J.; Matthiae, G.; Maurizio, D.; Mayotte, E.; Mazur, P. O.; Medina, C.; Medina-Tanco, G.; Meissner, R.; Mello, V. B. B.; Melo, D.; Menshikov, A.; Messina, S.; Micheletti, M. I.; Middendorf, L.; Minaya, I. A.; Miramonti, L.; Mitrica, B.; Molina-Bueno, L.; Mollerach, S.; Montanet, F.; Morello, C.; Mostafá, M.; Moura, C. A.; Muller, M. A.; Müller, G.; Müller, S.; Navas, S.; Necesal, P.; Nellen, L.; Nelles, A.; Neuser, J.; Nguyen, P. H.; Niculescu-Oglinzanu, M.; Niechciol, M.; Niemietz, L.; Niggemann, T.; Nitz, D.; Nosek, D.; Novotny, V.; Nožka, L.; Núñez, L. A.; Ochilo, L.; Oikonomou, F.; Olinto, A.; Pacheco, N.; Pakk Selmi-Dei, D.; Palatka, M.; Pallotta, J.; Papenbreer, P.; Parente, G.; Parra, A.; Paul, T.; Pech, M.; PÈ©kala, J.; Pelayo, R.; Pepe, I. M.; Perrone, L.; Petermann, E.; Peters, C.; Petrera, S.; Petrov, Y.; Phuntsok, J.; Piegaia, R.; Pierog, T.; Pieroni, P.; Pimenta, M.; Pirronello, V.; Platino, M.; Plum, M.; Porcelli, A.; Porowski, C.; Prado, R. R.; Privitera, P.; Prouza, M.; Quel, E. J.; Querchfeld, S.; Quinn, S.; Rautenberg, J.; Ravel, O.; Ravignani, D.; Reinert, D.; Revenu, B.; Ridky, J.; Risse, M.; Ristori, P.; Rizi, V.; Rodrigues de Carvalho, W.; Rodriguez Rojo, J.; Rodríguez-Frías, M. D.; Rogozin, D.; Rosado, J.; Roth, M.; Roulet, E.; Rovero, A. C.; Saffi, S. J.; Saftoiu, A.; Salazar, H.; Saleh, A.; Salesa Greus, F.; Salina, G.; Sanabria Gomez, J. D.; Sánchez, F.; Sanchez-Lucas, P.; Santos, E.; Santos, E. M.; Sarazin, F.; Sarkar, B.; Sarmento, R.; Sarmiento-Cano, C.; Sato, R.; Scarso, C.; Schauer, M.; Scherini, V.; Schieler, H.; Schmidt, D.; Scholten, O.; Schoorlemmer, H.; Schovánek, P.; Schröder, F. G.; Schulz, A.; Schulz, J.; Schumacher, J.; Sciutto, S. J.; Segreto, A.; Settimo, M.; Shadkam, A.; Shellard, R. C.; Sigl, G.; Sima, O.; Śmiałkowski, A.; Šmída, R.; Snow, G. R.; Sommers, P.; Sonntag, S.; Sorokin, J.; Squartini, R.; Srivastava, Y. N.; Stanca, D.; Stanič, S.; Stapleton, J.; Stasielak, J.; Stephan, M.; Stutz, A.; Suarez, F.; Suarez Durán, M.; Suomijärvi, T.; Supanitsky, A. D.; Sutherland, M. S.; Swain, J.; Szadkowski, Z.; Taborda, O. A.; Tapia, A.; Tepe, A.; Theodoro, V. M.; Timmermans, C.; Todero Peixoto, C. J.; Toma, G.; Tomankova, L.; Tomé, B.; Tonachini, A.; Torralba Elipe, G.; Torres Machado, D.; Travnicek, P.; Trini, M.; Ulrich, R.; Unger, M.; Urban, M.; Valdés Galicia, J. F.; Valiño, I.; Valore, L.; van Aar, G.; van Bodegom, P.; van den Berg, A. M.; van Velzen, S.; van Vliet, A.; Varela, E.; Vargas Cárdenas, B.; Varner, G.; Vasquez, R.; Vázquez, J. R.; Vázquez, R. A.; Veberič, D.; Verzi, V.; Vicha, J.; Videla, M.; Villaseñor, L.; Vlcek, B.; Vorobiov, S.; Wahlberg, H.; Wainberg, O.; Walz, D.; Watson, A. A.; Weber, M.; Weidenhaupt, K.; Weindl, A.; Welling, C.; Werner, F.; Widom, A.; Wiencke, L.; Wilczyński, H.; Winchen, T.; Wittkowski, D.; Wundheiler, B.; Wykes, S.; Yang, L.; Yapici, T.; Yushkov, A.; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zepeda, A.; Zimmermann, B.; Ziolkowski, M.; Zuccarello, F.; Pierre Auger Collaboration

    2016-06-01

    We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8 ±0.7 (stat)±6.7 (syst) MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principles calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the direct calibration of any cosmic-ray radio detector against the well-established energy scale of the Pierre Auger Observatory.

  13. High-energy cosmic-ray electrons - A new measurement using transition-radiation detectors

    Science.gov (United States)

    Hartmann, G.; Mueller, D.; Prince, T.

    1977-01-01

    A new detector for cosmic-ray electrons, consisting of a combination of a transition-radiation detector and a shower detector, has been constructed, calibrated at accelerator beams, and exposed in a balloon flight under 5 g/sq cm of atmosphere. The design of this instrument and the methods of data analysis are described. Preliminary results in the energy range 9-300 GeV are presented. The energy spectrum of electrons is found to be significantly steeper than that of protons, consistent with a long escape lifetime of cosmic rays in the galaxy.

  14. Natural radiation doses for cosmic and terrestrial components in Costa Rica

    Energy Technology Data Exchange (ETDEWEB)

    Mora, Patricia [Centro de Investigacion en Ciencias Atomicas, Nucleares y Moleculares, Universidad de Costa Rica, San Pedro de Montes de Oca, San Jose (Costa Rica)]. E-mail: pmora@cariari.ucr.ac.cr; Picado, Esteban [Centro de Investigacion en Ciencias Atomicas, Nucleares y Moleculares, Universidad de Costa Rica, San Pedro de Montes de Oca, San Jose (Costa Rica); Minato, Susumu [Radiation Earth Science Laboratory, Yamaguchi-cho 9-6, Higashi-ku, Nagoya, 461-0024 (Japan)

    2007-01-15

    A study of external natural radiation, cosmic and terrestrial components, was carried out with in situ measurements using NaI scintillation counters while driving along the roads in Costa Rica for the period July 2003-July 2005. The geographical distribution of the terrestrial air-absorbed dose rates and the total effective dose rates (including cosmic) are represented on contour maps. Information on the population density of the country permitted the calculation of the per capita doses. The average effective dose for the total cosmic component was 46.88{+-}18.06 nSv h{sup -1} and the average air-absorbed dose for the terrestrial component was 29.52{+-}14.46 nGy h{sup -1}. The average total effective dose rate (cosmic plus terrestrial components) was 0.60{+-}0.18 mSv per year. The effective dose rate per capita was found to be 83.97 nSv h{sup -1} which gives an annual dose of 0.74 mSv. Assuming the world average for the internal radiation component, the natural radiation dose for Costa Rica will be 2.29 mSv annually.

  15. 9,400 years of cosmic radiation and solar activity from ice cores and tree rings.

    Science.gov (United States)

    Steinhilber, Friedhelm; Abreu, Jose A; Beer, Jürg; Brunner, Irene; Christl, Marcus; Fischer, Hubertus; Heikkilä, Ulla; Kubik, Peter W; Mann, Mathias; McCracken, Ken G; Miller, Heinrich; Miyahara, Hiroko; Oerter, Hans; Wilhelms, Frank

    2012-04-17

    Understanding the temporal variation of cosmic radiation and solar activity during the Holocene is essential for studies of the solar-terrestrial relationship. Cosmic-ray produced radionuclides, such as (10)Be and (14)C which are stored in polar ice cores and tree rings, offer the unique opportunity to reconstruct the history of cosmic radiation and solar activity over many millennia. Although records from different archives basically agree, they also show some deviations during certain periods. So far most reconstructions were based on only one single radionuclide record, which makes detection and correction of these deviations impossible. Here we combine different (10)Be ice core records from Greenland and Antarctica with the global (14)C tree ring record using principal component analysis. This approach is only possible due to a new high-resolution (10)Be record from Dronning Maud Land obtained within the European Project for Ice Coring in Antarctica in Antarctica. The new cosmic radiation record enables us to derive total solar irradiance, which is then used as a proxy of solar activity to identify the solar imprint in an Asian climate record. Though generally the agreement between solar forcing and Asian climate is good, there are also periods without any coherence, pointing to other forcings like volcanoes and greenhouse gases and their corresponding feedbacks. The newly derived records have the potential to improve our understanding of the solar dynamics and to quantify the solar influence on climate.

  16. Gravitational radiation resistance, radiation damping and field fluctuations

    Science.gov (United States)

    Schaefer, G.

    1981-03-01

    Application is made of two different generalized fluctuation-dissipation theorems and their derivations to the calculation of the gravitational quadrupole radiation resistance using the radiation-reaction force given by Misner, Thorne and Wheeler and the usual tidal force on one hand and the tidal force and the free gravitational radiation field on the other hand. The quantum-mechanical version (including thermal generalizations) of the well known classical quadrupole radiation damping formula is obtained as a function of the radiation resistance.

  17. On the radiative and thermodynamic properties of the Cosmic Microwave Background radiation using COBE FIRAS instrument data

    CERN Document Server

    Fisenko, Anatoliy I

    2014-01-01

    Use formulas to describe the monopole and dipole spectra of the Cosmic Microwave Background (CMB) radiation, the exact expressions for the temperature dependences of the radiative and thermodynamic functions, such as the total radiation power per unit area, total energy density, number density of photons, Helmholtz free energy density, entropy density, heat capacity at constant volume, pressure, enthalpy density, and internal energy density in the finite range of frequencies are obtained. Since the dependence of temperature upon the redshift z is known, the obtained expressions can be simply presented in z representation. Utilizing experimental data for the monopole and dipole spectra measured by the COBE FIRAS instrument in the 60 - 600 GHz frequency interval at the temperature T = 2.728 K, the values of the radiative and thermodynamic functions, as well as the radiation density constant a and the Stefan-Boltzmann constant are calculated. In the case of the dipole spectrum, the constants a and the Stefan-Bol...

  18. Energy deposition study of low-energy cosmic radiation at sea level

    Science.gov (United States)

    Wijesinghe, Pushpa

    In this dissertation work, a computer simulation model based on the Geant4 simulation package has been designed and developed to study the energy deposition and track structures of cosmic muons and their secondary electrons in tissue-like materials. The particle interactions in a cubic water volume were first simulated. To analyze the energy deposition and tracks in small structures, with the intention of studying the energy localization in nanometric structures such as DNA, the chamber was sliced in three dimentions. Validation studies have been performed by comparing the results with experimental, theoretical, and other simulation results to test the accuracy of the simulation model. A human body phantom in sea-level muon environment was modeled to measure the yearly dose to a human from cosmic muons. The yearly dose in this phantom is about 22 millirems. This is close to the accepted value for the yearly dose from cosmic radiation at sea level. Shielding cosmic muons with a concrete slab from 0 to 2 meters increased the dose received by the body. This dissertation presents an extensive study on the interactions of secondary electrons created by muons in water. Index words. Radiation Dosimetry Simulation, Track Structures, Sea-Level muon Flux, Energy Deposition

  19. High-impedence NbSi TES sensors for studying the cosmic microwave background radiation

    CERN Document Server

    Nones, Claudia; Benoit, Alain; Bergé, Laurent; Bideau, Aurelien; Camus, Philippe; Dumoulin, Louis; Monfardini, Alessandro; Rigaut, Olivier

    2012-01-01

    Precise measurements of the cosmic microwave background (CMB) are crucial in cosmology, because any proposed model of the universe must account for the features of this radiation. Of all CMB measurements that the scientific community has not yet been able to perform, the CMB B-mode polarization is probably the most challenging from the instrumental point of view. The signature of primordial gravitational waves, which give rise to a B-type polarization, is one of the goals in cosmology today and amongst the first objectives in the field. For this purpose, high-performance low-temperature bolometric cameras, made of thousands of pixels, are currently being developed by many groups, which will improve the sensitivity to B-mode CMB polarization by one or two orders of magnitude compared to the Planck satellite HFI detectors. We present here a new bolometer structure that is able to increase the pixel sensitivities and to simplify the fabrication procedure. This innovative device replaces delicate membrane-based s...

  20. Quantum collapse as source of the seeds of cosmic structure during the radiation era

    CERN Document Server

    León, Gabriel; Piccirilli, María Pía

    2014-01-01

    The emergence of the seeds of cosmic structure, from a perfect isotropic and homogeneous Universe, has not been clearly explained by the standard version of inflationary models as the dynamics involved preserve the homogeneity and isotropy at all times. A proposal that attempts to deal with this problem, by introducing "the self-induced collapse hypothesis," has been introduced by D. Sudarsky and collaborators in previous papers. In all these works, the collapse of the wave function of the inflaton mode is restricted to occur during the inflationary period. In this paper, we analyse the possibility that the collapse happens during the radiation era. A viable model can be constructed under the condition that the inflaton field variable must be affected by the collapse while the momentum variable can or cannot be affected. Another condition to be fulfilled is that the time of collapse must be independent of $k$. However, when comparing with recent observational data, the predictions of the model cannot be disti...

  1. CHARM Facility Test Area Radiation Field Description

    CERN Document Server

    Thornton, Adam

    2016-01-01

    Specification document summarising the radiation field of the CHARM facility test area. This will act as a guide to any potential users of the facility as to what they can expect in terms of radiation, given in the form of radiation spectra information and fluence for each test position, along with general radiation maps for the test area and Montrac test location.

  2. Investigation of energy spectrum and nuclear interactions of primary cosmic radiation; Badanie widma energetycznego i oddzialywan jadrowych pierwotnego promieniowania kosmicznego

    Energy Technology Data Exchange (ETDEWEB)

    Wilczynski, H. [Dept. of High Energy Physics, The H. Niewodniczanski Inst. of Nuclear Physics, Cracow (Poland)

    1996-12-31

    In the paper the JACEE experiment data analysis: energy spectra in the energy range 10{sup 12} - 10{sup 15} eV of different nuclides in cosmic radiation and some aspects of nuclear interactions at energy above 10{sup 12} eV/nucleon is presented. The data were compared with results of theory of cosmic radiation acceleration by striking waves arises from supernova stars explosions. In the interactions of cosmic radiation nuclei the short-lived particles production has been observed what agrees with long-distance component of cascades initiated by cosmic radiation interactions. In one case an interaction with asymmetric photons emission were observed 72 refs, 33 figs, 4 tabs

  3. Lyman-alpha radiation hydrodynamics of galactic winds before cosmic reionization

    CERN Document Server

    Smith, Aaron; Loeb, Abraham

    2016-01-01

    The dynamical impact of Lyman-alpha (Ly{\\alpha}) radiation pressure on galaxy formation depends on the rate and duration of momentum transfer between Ly{\\alpha} photons and neutral hydrogen gas. Although photon trapping has the potential to multiply the effective force, ionizing radiation from stellar sources may relieve the Ly{\\alpha} pressure before appreciably affecting the kinematics of the host galaxy or efficiently coupling Ly{\\alpha} photons to the outflow. We present self-consistent Ly{\\alpha} radiation-hydrodynamics simulations of high-$z$ galaxy environments by coupling the Cosmic Ly{\\alpha} Transfer code (COLT) with spherically symmetric Lagrangian frame hydrodynamics. The accurate but computationally expensive Monte-Carlo radiative transfer calculations are feasible under the one-dimensional approximation. In certain cases Ly{\\alpha} feedback significantly enhances the velocity of the shell of gas expanding around a central source. Radiative feedback alone is capable of ejecting baryons into the i...

  4. Electron Heating, Magnetic Field Amplification, and Cosmic Ray Precursor Length at Supernova Remnant Shocks

    CERN Document Server

    Laming, J Martin; Ghavamian, Parviz; Rakowski, Cara

    2014-01-01

    We investigate the observability, by direct and indirect means, of a shock precursor arising from magnetic field amplification by cosmic rays. We estimate the depth of such a precursor under conditions of nonresonant amplification, which can provide magnetic field strengths comparable to those inferred for supernova remnants. Magnetic field generation occurs as the streaming cosmic rays induce a plasma return current, and may be quenched either by nonresonant or resonant channels. In the case of nonresonant saturation, the cosmic rays become magnetized and amplification saturates at higher magnetic fields. The precursor can extend out to $10^{17} - 10^{18}$ cm and is potentially detectable. If resonant saturation occurs, the cosmic rays are scattered by turbulence and the precursor length will likely be much smaller. The dependence of precursor length on shock velocity has implications for electron heating. In the case of resonant saturation, this dependence is similar to that in the more familiar resonantly ...

  5. On the Light Speed Anisotropy vs Cosmic Microwave Background Dipole: European Synchrotron Radiation Facility Measurements

    CERN Document Server

    Gurzadyan, V G; Kashin, A; Margarian, A T; Bartalini, O; Bellini, V; Castoldi, M; D'Angelo, A; Didelez, J P; Salvo, R D; Fantini, A; Gervino, G; Ghio, F; Girolami, B; Giusa, A; Guidal, M; Hourany, E; Knyazyan, S; Kouznetsov, V; Kunne, Ronald Alexander; Lapik, A; Levi-Sandri, P; Llères, A; Mehrabyan, S S; Moricciani, D; Nedorezov, V; Perrin, C; Rebreyend, D; Russo, G; Rudnev, N; Schärf, C; Sperduto, M L; Sutera, M C; Turinge, A

    2007-01-01

    The measurement of the Compton edge of the scattered electrons in GRAAL facility in European Synchrotron Radiation Facility (ESRF) in Grenoble with respect to the Cosmic Microwave Background dipole reveals up to 10 sigma variations larger than the statistical errors. We now show that the variations are not due to the frequency variations of the accelerator. The nature of Compton edge variations remains unclear, thus outlining the imperative of dedicated studies of light speed anisotropy.

  6. What is cosmic radiation?; Qu'est ce-que le rayonnement cosmique?

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    The earth was indeed receiving ionizing radiations from the heavens. This cosmic radiation consists of particles travelling near the speed of light. It consists of two components, the first of which is permanent and of galactic origin, while the other is more sporadic, depending on the sun's activities. Natural land-based sources expose each of us to an average total dose of 2.4 mSv per year (source UNSCEAR). In addition, the human activities using ionizing radiation contribute to an average annual exposure of 1.4 mSv, originating primarily with medical activities ( radiodiagnostic and radiation therapy). Members of flights crew are subject to exposure. The total dose of cosmic radiation received is is directly proportional with the duration of exposure, and thus with the duration of the flight. Measurement taken on board aircraft during the 1990's showed that flight personnel (on long haul flights) receive an average dose of approximately the same magnitude as the one due to exposure to natural radioactivity in France. The damage caused by ionizing radiation depends on the quantity of energy released by radiation into the cells of each organ or tissue of the human body(exposure dose). For a given quantity of absorbed energy (dose expressed in Gray), the damage will vary according to the nature of the radiation and the affected organ. These effects are of two types: acute effects and deferred effects. Two measurements are essential for radiation protection: the measurements of the dose of radiation absorbed by the body and the assessment of the risk associated with the absorbed dose. Two units were thus created: the gray and the sievert. (N.C.)

  7. Analysis of the nature of excessive cosmic radiation in the area of the Brazilian magnetic anomaly at altitudes 250-500km, from Kosmos-225 satellite data

    Science.gov (United States)

    Raychenko, L. V.

    1974-01-01

    Results are presented from a study of the region of anomalous cosmic radiation in the area of the Brazilian magnetic anomaly at the altitudes 250-500 km, using data measurements taken on the Kosmos-225 satellite (14-29 June 1968). The existence of a stable intensity anomaly discovered in the experiments on the second and third Soviet spacecraft-satellites is confirmed. The total vector of the geomagnetic field at different altitudes was compared with isoline maps. An altitude profile of the South Atlantic anomaly of radiation intensity was obtained, using data from the same instrument. The nature of the anomalies in cosmic radiation intensity over the regions of negative magnetic anomalies is discussed.

  8. Airline pilot cosmic radiation and circadian disruption exposure assessment from logbooks and company records.

    Science.gov (United States)

    Grajewski, Barbara; Waters, Martha A; Yong, Lee C; Tseng, Chih-Yu; Zivkovich, Zachary; Cassinelli, Rick T

    2011-06-01

    US commercial airline pilots, like all flight crew, are at increased risk for specific cancers, but the relation of these outcomes to specific air cabin exposures is unclear. Flight time or block (airborne plus taxi) time often substitutes for assessment of exposure to cosmic radiation. Our objectives were to develop methods to estimate exposures to cosmic radiation and circadian disruption for a study of chromosome aberrations in pilots and to describe workplace exposures for these pilots. Exposures were estimated for cosmic ionizing radiation and circadian disruption between August 1963 and March 2003 for 83 male pilots from a major US airline. Estimates were based on 523 387 individual flight segments in company records and pilot logbooks as well as summary records of hours flown from other sources. Exposure was estimated by calculation or imputation for all but 0.02% of the individual flight segments' block time. Exposures were estimated from questionnaire data for a comparison group of 51 male university faculty. Pilots flew a median of 7126 flight segments and 14 959 block hours for 27.8 years. In the final study year, a hypothetical pilot incurred an estimated median effective dose of 1.92 mSv (absorbed dose, 0.85 mGy) from cosmic radiation and crossed 362 time zones. This study pilot was possibly exposed to a moderate or large solar particle event a median of 6 times or once every 3.7 years of work. Work at the study airline and military flying were the two highest sources of pilot exposure for all metrics. An index of work during the standard sleep interval (SSI travel) also suggested potential chronic sleep disturbance in some pilots. For study airline flights, median segment radiation doses, time zones crossed, and SSI travel increased markedly from the 1990s to 2003 (P(trend) airline pilots, many of whom have been exposed to increasing cosmic radiation and circadian disruption from the 1990s through 2003. This assessment is likely to decrease exposure

  9. Gravitational Radiation from Ultra High Energy Cosmic Rays in Models with Large Extra Dimensions

    CERN Document Server

    Koch, B; Bleicher, M; Koch, Ben; Drescher, Hans-Joachim; Bleicher, Marcus

    2006-01-01

    The effects of classical gravitational radiation in models with large extra dimensions are investigated for ultra high energy cosmic rays (CRs). The cross sections are implemented into a simulation package (SENECA) for high energy hadron induced CR air showers. We predict that gravitational radiation from quasi-elastic scattering could be observed at incident CR energies above $10^9$ GeV for a setting with more than two extra dimensions. It is further shown that this gravitational energy loss can alter the energy reconstruction for CR energies $E_{\\rm CR}\\ge 5\\cdot 10^9$ GeV.

  10. Probing the Light Speed Anisotropy with respect to the Cosmic Microwave Background Radiation Dipole

    CERN Document Server

    Gurzadyan, V G; Kashin, A L; Margarian, A T; Bartalini, O; Bellini, V; Castoldi, M; D'Angelo, A; Didelez, J P; Salvo, R D; Fantini, A; Gervino, G; Ghio, F; Girolami, B; Giusa, A; Hourany, E; Knyazyan, S; Kuznetsov, V E; Lapik, A; Levi-Sandri, P; Llères, A; Mehrabyan, S S; Moricciani, D; Nedorezov, V; Perrin, C; Rebreyend, D; Russo, G; Rudnev, N; Schärf, C; Sperduto, M L; Sutera, M C; Turinge, A

    2005-01-01

    We have studied the angular fluctuations in the speed of light with respect to the apex of the dipole of Cosmic Microwave Background (CMB) radiation using the experimental data obtained with GRAAL facility, located at the European Synchrotron Radiation Facility (ESRF) in Grenoble. The measurements were based on the stability of the Compton edge of laser photons scattered on the 6 GeV monochromatic electron beam. The results enable to obtain a conservative constraint on the anisotropy in the light speed variations \\Delta c(\\theta)/c < 3 10^{-12}, i.e. with higher precision than from previous experiments.

  11. Rydberg atom detection of the temporal coherence of cosmic microwave background radiation

    CERN Document Server

    Tscherbul, Timur V

    2013-01-01

    Rydberg atoms immersed in cold blackbody radiation are shown to display long-lived quantum coherence effects on timescales of tens of picoseconds. By solving non-Markovian equations of motion with no free parameters we obtain the time evolution of the density matrix, and demonstrate that the blackbody-induced temporal coherences manifest as quantum beats in time-resolved fluorescence intensities of the Rydberg atoms. A measurable fluorescence signal can be obtained with a cold trapped ensemble of 1e8 Rydberg atoms subject to 2.7 K cosmic microwave background radiation (CMB), allowing for novel insights into previously unexamined quantum coherence properties of CMB.

  12. Effects of Nuclear Cross Sections at Different Energies on the Radiation Hazard from Galactic Cosmic Rays

    Science.gov (United States)

    Lin, Z. W.; Adams, J. H., Jr.

    2006-01-01

    The radiation hazard for astronauts from galactic cosmic rays is a major obstacle in long duration human space explorations. Space radiation transport codes have been developed to calculate radiation environment on missions to the Moon, Mars or beyond. We have studied how uncertainties in fragmentation cross sections at different energies affect the accuracy of predictions from such radiation transport. We find that, in deep space, cross sections between 0.3 and 0.85 GeV/u usually have the largest effect on dose-equivalent behind shielding in solar minimum GCR environments, and cross sections between 0.85 and 1.2 GeV/u have the largest effect in solar maximum GCR environments. At the International Space Station, cross sections at higher energies have the largest effect due to the geomagnetic cutoff.

  13. Evaluation of exposure to cosmic radiation of flight crews of Lithuanian airlines.

    Science.gov (United States)

    Morkŭnas, Gendrutis; Pilkyte, Laima; Ereminas, Darius

    2003-01-01

    In Lithuania the average annual effective dose due to cosmic radiation at the sea level is 0.38 mSv. The dose rate caused by cosmic radiation increases with altitude due to the decrease in attenuation of cosmic radiation by atmosphere. Dose rates at altitudes of commercial flights are tens times higher than those at the sea level. For this reason people who frequently fly receive higher doses which might even be subject to legal regulations. The European Council Directive (96/29/Euratom) on basic radiation safety standards requires that doses of aircrews members be assessed and the appropriate measures taken, depending on the assessment results. The aim of this study was to evaluate potential doses, which can be received by members of aircrews of Lithuanian Airlines. The assessment was done by performing measurements and calculations. Measurements were performed in flying aircrafts by thermoluminescent detectors, Geiger Muller counters and neutron rem counter. Such an approach lead to evaluation of doses due to directly ionizing particles and neutrons. Calculations were done with the help of the code CARI-6M. Such parameters as flight route, solar activity, duration and altitudes of flight were taken into account. Doses received during different flights and in different aircrafts were assessed. The results of measurements and calculations were compared and differences discussed. The results were also compared with the data obtained in other similar studies. It was found that the highest doses are received in flights to Paris, London, Amsterdam, and Frankfurt by aircraft B737. A number of flights causing annual doses higher than 1 mSv was estimated. Despite the fact that only European flights are operated by Lithuanian Airlines the dose of 1 mSv may be exceeded under some circumstances. If it happens some radiation protection measures shall be taken. These measures are also discussed.

  14. Lyman-alpha radiation hydrodynamics of galactic winds before cosmic reionization

    Science.gov (United States)

    Smith, Aaron; Bromm, Volker; Loeb, Abraham

    2017-01-01

    Radiation from the first stars and galaxies initiated the dramatic phase transition marking an end to the cosmic dark ages. The emission and absorption signatures from the Lyman-alpha transition of neutral hydrogen have been indispensable in extending the observational frontier for high-redshift galaxies into the epoch of reionization. Lyman-alpha radiative transfer provides clues about the processes leading to Lyman-alpha escape from individual galaxies and the subsequent transmission through the intergalactic medium. Cosmological simulations incorporating Lyman-alpha radiative transfer enhance our understanding of fundamental physics by supplying the inferred spectra and feedback on the gas. We discuss the dynamical impact of Lyman-alpha radiation pressure on galaxy formation throughout cosmic reionization with the first fully coupled Lyman-alpha radiation-hydrodynamics simulations. We self-consistently follow the chemistry, cooling, self-gravity, and ionizing radiation in protogalaxies and find that Lyman-alpha radiation pressure turns out to be dynamically important in several spherically symmetric simulations. As a case in point we apply our model to the COSMOS redshift 7 (CR7) galaxy at z = 6.6, which exhibits a +160 km/s velocity offset between the Lyman-alpha and HeII line peaks. We find that a massive black hole with a nonthermal Compton-thick spectrum is able to reproduce the observed Lyman-alpha signatures as a result of higher photon trapping and longer potential lifetime. We conclude with a general discussion of Lyman-alpha radiation in the first galaxies by considering simulations that cover the expected range of halo and source properties.

  15. Atmospheric Radiation Modeling of Galactic Cosmic Rays Using LRO/CRaTER and the EMMREM Model with Comparisons to Balloon and Airline Based Measurements

    Science.gov (United States)

    Joyce, C. J.

    2016-12-01

    The current state of the Sun and solar wind, with uncommonly low densities and weak magnetic fields, has resulted in galactic cosmic ray fluxes that are elevated to levels higher than have ever before been observed in the space age. Given the continuing trend of declining solar activity, it is clear that accurate modeling of GCR radiation is becoming increasingly important in the field of space weather. Such modelling is essential not only in the planning of future manned space missions, but is also important for assessing the radiation risks to airline passengers, particularly given NASA's plans to develop supersonic aircraft that will fly at much higher altitudes than commercial aircraft and thus be more vulnerable to radiation from GCRs. We provide an analysis of the galactic cosmic ray radiation environment of Earth's atmosphere using measurements from the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) aboard the Lunar Reconnaissance Orbiter (LRO) together with the Badhwar-O'Neil model and dose lookup tables generated by the Earth-Moon-Mars Radiation Environment Module (EMMREM). Newly available measurements of atmospheric dose rates from instruments aboard commercial and research aircraft enable evaluation of the accuracy of the model in computing atmospheric dose rates. Additionally, a newly available dataset of balloon-based measurements, including simultaneous balloon launches from California and New Hampshire, provide an additional means of comparison to the model. When compared to the available observations of atmospheric radiation levels, the computed dose rates seem to be sufficiently accurate, falling within recommended radiation uncertainty limits.

  16. Viscosity and inertia in cosmic-ray transport - Effects of an average magnetic field

    Science.gov (United States)

    Williams, L. L.; Jokipii, J. R.

    1991-01-01

    A generalized transport equation is introduced which describes the transport and propagation of cosmic rays in a magnetized, collisionless medium. The equation is valid if the cosmic-ray distribution function is nearly isotropic in momentum, if the ratio of fluid speed to fluid-flow particle speed is small, and if the ratio of collision time to time for change in the macroscopic flow is small. Five independent cosmic-ray viscosity coefficients are found, and the ralationship of this viscosity to particle orbits in a magnetic field is presented.

  17. The High Energy cosmic-Radiation Detection (HERD) Facility onboard China's Future Space Station

    CERN Document Server

    Zhang, S N

    2014-01-01

    The High Energy cosmic-Radiation Detection (HERD) facility is one of several space astronomy payloads of the cosmic lighthouse program onboard China's Space Station, which is planned for operation starting around 2020 for about 10 years. The main scientific objectives of HERD are indirect dark matter search, precise cosmic ray spectrum and composition measurements up to the knee energy, and high energy gamma-ray monitoring and survey. HERD is composed of a 3-D cubic calorimeter (CALO) surrounded by microstrip silicon trackers (STKs) from five sides except the bottom. CALO is made of about 10$^4$ cubes of LYSO crystals, corresponding to about 55 radiation lengths and 3 nuclear interaction lengths, respectively. The top STK microstrips of seven X-Y layers are sandwiched with tungsten converters to make precise directional measurements of incoming electrons and gamma-rays. In the baseline design, each of the four side SKTs is made of only three layers microstrips. All STKs will also be used for measuring the cha...

  18. Characteristic of the radiation field in low Earth orbit and in deep space.

    Science.gov (United States)

    Reitz, Guenther

    2008-01-01

    The radiation exposure in space by cosmic radiation can be reduced through careful mission planning and constructive measures as example the provision of a radiation shelter, but it cannot be completely avoided. The reason for that are the extreme high energies of particles in this field and the herewith connected high penetration depth in matter. For missions outside the magnetosphere ionizing radiation is recognized as the key factor through its impact on crew health and performance. In absence of sporadic solar particle events the radiation exposure in Low Earth orbit (LEO) inside Spacecraft is determined by the galactic cosmic radiation (protons and heavier ions) and by the protons inside the South Atlantic Anomaly (SAA), an area where the radiation belt comes closer to the earth surface due to a displacement of the magnetic dipole axes from the Earth's center. In addition there is an albedo source of neutrons produced as interaction products of the primary galactic particles with the atoms of the earth atmosphere. Outside the spacecraft the dose is dominated by the electrons of the horns of the radiation belt located at about 60" latitude in Polar Regions. The radiation field has spatial and temporal variations in dependence of the Earth magnetic field and the solar cycle. The complexity of the radiation field inside a spacecraft is further increased through the interaction of the high energy components with the spacecraft shielding material and with the body of the astronauts. In interplanetary missions the radiation belt will be crossed in a couple of minutes and therefore its contribution to their radiation exposure is quite small, but subsequently the protection by the Earth magnetic field is lost, leaving only shielding measures as exposure reduction means. The report intends to describe the radiation field in space, the interaction of the particles with the magnetic field and shielding material and give some numbers on the radiation exposure in low earth

  19. Cosmic-ray diffusion in a sectored magnetic field in the distant heliosheath

    CERN Document Server

    Florinski, V; Kota, J; Guo, X; 10.1088/0004-637X/754/1/31

    2013-01-01

    Very high intensities of galactic cosmic rays measured by Voyager 1 in the heliosheath appear to be incompatible with the presence of a modulation "wall" near the heliopause produced by a pile up of the heliospheric magnetic field. We propose that the modulation wall is a structure permeable to cosmic rays as a result of a sectored magnetic field topology compressed by plasma slowdown on approach to the heliopause and stretched to high latitudes by latitudinal flows in the heliosheath. The tightly folded warped current sheet permits efficient cosmic-ray transport in the radial direction via a drift-like mechanism. We show that when stochastic variations in the sector widths are taken into account, particle transport becomes predominantly diffusive both along and across the magnetic sectors. Using a test-particle model for cosmic rays in the heliosheath we investigate the dependence of the diffusion coefficients on the properties of the sector structure and on particle energy.

  20. COSMIC-RAY DIFFUSION IN A SECTORED MAGNETIC FIELD IN THE DISTANT HELIOSHEATH

    Energy Technology Data Exchange (ETDEWEB)

    Florinski, V. [Department of Physics, University of Alabama, Huntsville, AL 35899 (United States); Alouani-Bibi, F.; Guo, X. [Center for Space Plasma and Aeronomic Research, University of Alabama, Huntsville, AL 35899 (United States); Kota, J. [Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721 (United States)

    2012-07-20

    Very high intensities of galactic cosmic rays measured by Voyager 1 in the heliosheath appear to be incompatible with the presence of a modulation 'wall' near the heliopause produced by a pile up of the heliospheric magnetic field. We propose that the modulation wall is a structure permeable to cosmic rays as a result of a sectored magnetic field topology compressed by plasma slowdown on approach to the heliopause and stretched to high latitudes by latitudinal flows in the heliosheath. The tightly folded warped current sheet permits efficient cosmic-ray transport in the radial direction via a drift-like mechanism. We show that when stochastic variations in the sector widths are taken into account, particle transport becomes predominantly diffusive both along and across the magnetic sectors. Using a test-particle model for cosmic rays in the heliosheath we investigate the dependence of the diffusion coefficients on the properties of the sector structure and on particle energy.

  1. Investigations of aircrews exposure to cosmic radiation - results, conclusions and suggestions

    CERN Document Server

    Bilski, P; Horwacik, T; Marczewska, B; Ochab, E; Olko, P

    2002-01-01

    In frame of a research project undertaken in collaboration with Polish airlines LOT, analysis of aircrews exposure to cosmic radiation has been performed. The applied methods included measurements of radiation doses with thermoluminescent detectors (MTS-N, MCP-N) and track detectors (CR-39) and also calculations of route doses with the CARI computer code. The obtained results indicate that aircrews of nearly all airplanes, with exception of these flying only on ATR aircraft, exceed regularly or may exceed in some conditions, effective doses of 1 mSv. In case of Boeing-767 aircrews such exceeding occurs always, independently of solar activity. Investigations revealed, that during these periods of the solar cycle, when intensity of cosmic radiation is high, exceeding of 6 mSv level is also possible. These results indicate, that according to Polish and European regulations it is necessary for airlines to provide regular estimations of radiation exposure of aircrews. Basing on the obtained results a system for pe...

  2. Cosmic Ray Test of Mini-drift Thick Gas Electron Multiplier Chamber for Transition Radiation Detector

    CERN Document Server

    Yang, S; Buck, B; Li, C; Ljubicic, T; Majka, R; Shao, M; Smirnov, N; Visser, G; Xu, Z; Zhou, Y

    2014-01-01

    A thick gas electron multiplier (THGEM) chamber with an effective readout area of 10$\\times$10 cm$^{2}$ and a 11.3 mm ionization gap has been tested along with two regular gas electron multiplier (GEM) chambers in a cosmic ray test system. The thick ionization gap makes the THGEM chamber a mini-drift chamber. This kind mini-drift THGEM chamber is proposed as part of a transition radiation detector (TRD) for identifying electrons at an Electron Ion Collider (EIC) experiment. Through this cosmic ray test, an efficiency larger than 94$\\%$ and a spatial resolution $\\sim$220 $\\mu$m are achieved for the THGEM chamber at -3.65 kV. Thanks to its outstanding spatial resolution and thick ionization gap, the THGEM chamber shows excellent track reconstruction capability. The gain uniformity and stability of the THGEM chamber are also presented.

  3. Bursts of gravitational radiation from superconducting cosmic strings and the neutrino mass spectrum

    Energy Technology Data Exchange (ETDEWEB)

    Mosquera Cuesta, Herman J. [Abdus Salam International Centre for Theoretical Physics, Trieste (Italy)]|[Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil). Lab. de Cosmologia e Fisica Experimental de Altas Energias; Morejon Gonzalez, Danays [Pontificia Univ. Catolica do Rio de Janeiro, RJ (Brazil)

    2001-02-01

    Berezinsky, Hnatyk and Vilenkin showed that superconducting cosmic strings could be central engines for cosmological gamma-ray bursts and for producing the neutrino component of ultra-high energy cosmic rays. A consequence of this mechanism would be that a detectable cusp-triggered gravitational wave burst should be release simultaneously with the {gamma}-ray surge. If contemporary measurements of both {gamma} and {nu} radiation could be made for any particular source, then the cosmological time-delay between them might be useful for putting unprecedently tight bounds on the neutrino mass spectrum. Such measurements could consistently verify or rule out the model since strictly correlated behaviour is expected for the duration of the event and for the time variability of the spectra. (author)

  4. Changes in cosmic ray cut-off rigidities due to secular variations of the geomagnetic field

    Directory of Open Access Journals (Sweden)

    A. Bhattacharyya

    Full Text Available An analytical expression is derived for the cutoff rigidity of cosmic rays arriving at a point in an arbitrary direction, when the main geomagnetic field is approximated by that of an eccentric dipole. This expression is used to determine changes in geomagnetic cutoffs due to secular variation of the geomagnetic field since 1835. Effects of westward drift of the quadrupole field and decrease in the effective dipole moment are seen in the isorigidity contours. On account of the immense computer time required to determine the cutoff rigidities more accurately using the particle trajectory tracing technique, the present formulation may be useful in estimating the transmission factor of the geomagnetic field in cosmic ray studies, modulation of cosmogenic isotope production by geomagnetic secular variation, and the contribution of geomagnetic field variation to long term changes in climate through cosmic ray related modulation of the current flow in the global electric circuit.

  5. Cosmic Radiation and Aircrew Exposure: Implementation of European Requirements in Civil Aviation, Dublin, 1-3 July 1998

    Science.gov (United States)

    Talbot, Lee

    1999-03-01

    The European Union's Basic Safety Standards Directive (96/29/Euratom) lays down safety standards for the protection of workers and the general public against the effects of ionising radiations. Article 42 of the Directive deals with the protection of aircrew. It states that for crew of jet aircraft who are likely to be subject to exposure to more than 1 mSv y-1 appropriate measures must be taken, in particular: to assess the exposure of the crew concerned, to take into account the assessed exposure when organising working schedules with a view to reducing the doses of highly exposed aircrew, to inform concerned workers of the health risks involved in their work, to apply Article 10 to female aircrew. (The unborn child shall be treated like a member of the public.) This Directive must be transformed into national law of the 15 member states of the European Union by 13 May 2000. The European Commission and the Radiological Protection Institute of Ireland sponsored this International Conference. The objective of this conference was to assist both the airline industry and the national regulatory organisations in identifying the means available to comply with the requirements of the Directive. Over 200 delegates attended the conference from more than 25 countries. The welcoming addresses were made by Mary Upton (Director of the Radiological Protection Institute of Ireland), Joe Jacob (Minister for State responsible for Nuclear Safety) and James Currie (Director-General for the Environment, Nuclear Safety and Civil Protection). Mr Currie stated that there was a need for political decisions to be based on good science, and that technological trends will lead to higher and longer flights, and therefore higher radiation doses. The first day concentrated on the scientific basis of measurement, calculation and monitoring of cosmic radiation. The first speaker, Dr Heinrich from the University of Siegen, Germany, talked about the physics of cosmic radiation fields. He pointed

  6. Primordial Gravitational Waves and Rescattered Electromagnetic Radiation in the Cosmic Microwave Background

    CERN Document Server

    Kim, Dong-Hoon

    2016-01-01

    Understanding the interaction of primordial gravitational waves (GWs) with the Cosmic Microwave Background (CMB) plasma is important for observational cosmology. In this article, we provide an analysis of an effect apparently overlooked as yet. We consider a single free electric charge and suppose that it can be agitated by primordial GWs propagating through the CMB plasma, resulting in periodic, regular motion along particular directions. Light reflected by the charge will be partially polarized, and this will imprint a characteristic pattern on the CMB. We study this effect by considering a simple model in which anisotropic incident electromagnetic (EM) radiation is rescattered by a charge sitting in spacetime perturbed by GWs and becomes polarized. As the charge is driven to move along particular directions, we calculate its dipole moment to determine the leading-order rescattered EM radiation. The Stokes parameters of the rescattered radiation exhibit a net linear polarization. We investigate how this pol...

  7. Cosmic and solar radiation exposure for aircrew over a solar cycle

    Energy Technology Data Exchange (ETDEWEB)

    Desormeaux, M. [Royal Military College of Canada, Dept. of Chemistry and Chemical Engineering, Kingston, Ontario (Canada)

    2003-07-01

    Over the past decade, extensive research has been performed at the Royal Military College of Canada to determine the radiation exposure of aircrew, and to assess the recommendation of the International Commission for Radiological Protection (ICRP) that aircrew should be considered as occupationally exposed workers. This research confirmed the ICRP findings and demonstrated that galactic cosmic radiation could be effectively predicted, which has led to the development of a semi-empirical computer model capable of predicting route doses over an entire solar cycle. Following ongoing validation, model improvement has been performed for short-haul and low-altitude flights, as well as flights done during solar minimum conditions. Furthermore, a model has also been proposed to account for the additional radiation exposure from solar particle events (SPEs). (author)

  8. Cosmic and solar radiation exposure for aircrew over a solar cycle

    Energy Technology Data Exchange (ETDEWEB)

    Desormeaux, M. [Royal Military College of Canada, Kingston, Ontario (Canada)

    2003-08-01

    Over the past decade, extensive research has been performed at the Royal Military College of Canada to determine the radiation exposure of aircrew, and to assess the recommendation of the International Commission for Radiological Protection (ICRP) that aircrew should be considered as occupationally exposed workers. This research confirmed the ICRP findings and demonstrated that galactic cosmic radiation could be effectively predicted, which has led to the development of a semi-empirical computer model capable of predicting route doses over an entire solar cycle. Following ongoing validation, model improvement has been performed for short-haul and low-altitude flights, as well as flights done during solar minimum conditions. Furthermore, a model has also been proposed to account for the additional radiation exposure from solar particle events (SPEs). (author)

  9. New Measurements of the Cosmic Background Radiation Spectrum

    Science.gov (United States)

    Smoot, G. F.; De Amici, G.; Levin, S.; Witebsky, C.

    We continue consideration of ways-and-means for creating, in an evolutionary, ever-more-powerful manner, a continually-updated data-base of salient atmospheric properties sufficient for finite differenced integration-based, high-fidelity weather prediction over intervals of 2-3 weeks, leveraging the 10{sup 14} FLOPS digital computing systems now coming into existence. A constellation comprised of 10{sup 6}-10{sup 9} small atmospheric sampling systems--high-tech superpressure balloons carrying early 21st century semiconductor devices, drifting with the local winds over the meteorological spectrum of pressure-altitudes--that assays all portions of the troposphere and lower stratosphere remains the central feature of the proposed system. We suggest that these devices should be active-signaling, rather than passive-transponding, as we had previously proposed only for the ground- and aquatic-situated sensors of this system. Instead of periodic interrogation of the intra-atmospheric transponder population by a constellation of sophisticated small satellites in low Earth orbit, we now propose to retrieve information from the instrumented balloon constellation by existing satellite telephony systems, acting as cellular tower-nodes in a global cellular telephony system whose ''user-set'' is the atmospheric-sampling and surface-level monitoring constellations. We thereby leverage the huge investment in cellular (satellite) telephony and GPS technologies, with large technical and economic gains. This proposal minimizes sponsor forward commitment along its entire programmatic trajectory, and moreover may return data of weather-predictive value soon after field activities commence. We emphasize its high near-term value for making better mesoscale, relatively short-term weather predictions with computing-intensive means, and its great long-term utility in enhancing the meteorological basis for global change predictive studies. We again note that adverse impacts of weather

  10. The Spectrumof the Cosmic Background Radiation: Early and RecentMeasurements from the White Mountain Research Station

    Energy Technology Data Exchange (ETDEWEB)

    Smoot, G.F.

    1985-09-01

    The White Mountain Research Station has provided a support facility at a high, dry, radio-quiet site for measurements that have established the blackbody character of the cosmic microwave background radiation. This finding has confirmed the interpretation of the radiation as a relic of the primeval fireball and helped to establish the hot Big Bang theory as the standard cosmological model.

  11. Cosmic-Ray Small-scale Anisotropies and Local Turbulent Magnetic Fields

    Science.gov (United States)

    López-Barquero, V.; Farber, R.; Xu, S.; Desiati, P.; Lazarian, A.

    2016-10-01

    Cosmic-ray anisotropy has been observed in a wide energy range and at different angular scales by a variety of experiments over the past decade. However, no comprehensive or satisfactory explanation has been put forth to date. The arrival distribution of cosmic rays at Earth is the convolution of the distribution of their sources and of the effects of geometry and properties of the magnetic field through which particles propagate. It is generally believed that the anisotropy topology at the largest angular scale is adiabatically shaped by diffusion in the structured interstellar magnetic field. On the contrary, the medium- and small-scale angular structure could be an effect of nondiffusive propagation of cosmic rays in perturbed magnetic fields. In particular, a possible explanation for the observed small-scale anisotropy observed at the TeV energy scale may be the effect of particle propagation in turbulent magnetized plasmas. We perform numerical integration of test particle trajectories in low-β compressible magnetohydrodynamic turbulence to study how the cosmic rays’ arrival direction distribution is perturbed when they stream along the local turbulent magnetic field. We utilize Liouville’s theorem for obtaining the anisotropy at Earth and provide the theoretical framework for the application of the theorem in the specific case of cosmic-ray arrival distribution. In this work, we discuss the effects on the anisotropy arising from propagation in this inhomogeneous and turbulent interstellar magnetic field.

  12. Propagation of ultrahigh energy cosmic rays in extragalactic magnetic fields: a view from cosmological simulations

    Science.gov (United States)

    Hackstein, S.; Vazza, F.; Brüggen, M.; Sigl, G.; Dundovic, A.

    2016-11-01

    We use the CRPROPA code to simulate the propagation of ultrahigh energy cosmic rays (with energy ≥1018eV and pure proton composition) through extragalactic magnetic fields that have been simulated with the cosmological ENZO code. We test both primordial and astrophysical magnetogenesis scenarios in order to investigate the impact of different magnetic field strengths in clusters, filaments and voids on the deflection of cosmic rays propagating across cosmological distances. We also study the effect of different source distributions of cosmic rays around simulated Milky Way-like observers. Our analysis shows that the arrival spectra and anisotropy of events are rather insensitive to the distribution of extragalactic magnetic fields, while they are more affected by the clustering of sources within an ˜50 Mpc distance to observers. Finally, we find that in order to reproduce the observed degree of isotropy of cosmic rays at ˜EeV energies, the average magnetic fields in cosmic voids must be ˜ 0.1 nG, providing limits on the strength of primordial seed fields.

  13. Features of the galactic magnetic field regarding deflections of ultra-high-energy cosmic rays

    Energy Technology Data Exchange (ETDEWEB)

    Wirtz, Marcus; Erdmann, Martin; Mueller, Gero; Urban, Martin [III. Physikalisches Institut A, RWTH Aachen University (Germany)

    2016-07-01

    Most recent models of the galactic magnetic field have been derived from Faraday rotation measurements and imply strong deflections even for ultra-high energy cosmic rays. We investigate the characteristics of the different field parametrizations and point out similarities and interesting features. Among them are extragalactic regions which are invisible for an Earth bound observation and the transition from diffuse to ballistic behaviour in the 1 EeV energy regime. Applying this knowledge to a directional analysis, there are indications for deflection patterns by the galactic magnetic field in cosmic ray arrival directions measured by the Pierre Auger Observatory.

  14. Quasi light fields: extending the light field to coherent radiation

    CERN Document Server

    Accardi, Anthony

    2009-01-01

    Imaging technologies such as dynamic viewpoint generation are engineered for incoherent radiation using the traditional light field, and for coherent radiation using electromagnetic field theory. We present a model of coherent image formation that strikes a balance between the utility of the light field and the comprehensive predictive power of Maxwell's equations. We synthesize research in optics and signal processing to formulate, capture, and form images from quasi light fields, which extend the light field from incoherent to coherent radiation. Our coherent cameras generalize the classic beamforming algorithm in sensor array processing, and invite further research on alternative notions of image formation.

  15. On the slow time geomagnetic field modulation of galactic cosmic rays

    Science.gov (United States)

    Okpala, Kingsley

    2016-07-01

    Cosmic rays of galactic origin are modulated by both heliospheric and geomagnetic conditions. The mutual (and mutually exclusive) contribution of both heliospheric and geomagnetic conditions to galactic cosmic rays (GCR) modulation is still an open question. While the rapid-time association of the galactic cosmic ray variation with different heliophysical and geophysical phenomena has been well studied, not so much attention has been paid to slow-time variations especially with regards to local effects. In this work, we employed monthly means of cosmic ray count rates from two mid latitude (Hermanus and Rome), and two higher latitude (Inuvik and Oulu) neutron monitors (NM), and compared their variability with geomagnetic stations that are in close proximity to the NMs. The data spans 1966 to 2008 and covers four (4) solar cycles. The difference (DeltaCR)between the mean count rate of all days and the mean of the five quietest days for each month was compared with the Dst-related disturbance (DeltaH) derived from the nearby geomagnetic stations. Zeroth- and First- correlation between the cosmic ray parameters and geomagnetic parameters was performed to ascertain statistical association and test for spurious association. Our results show that solar activity is generally strongly correlated (>0.75) with mean strength of GCR count rate and geomagnetic field during individual solar cycles. The correlation between mean strength of cosmic ray intensity and Geomagnetic field strength is spurious and is basically moderated by the solar activity. The signature of convection driven disturbances at high latitude geomagnetic stations was evident during the declining phase of the solar cycles close to the solar minimum. The absence of this feature in the slow-time varying cosmic ray count rates in all stations, and especially in the mid latitude geomagnetic stations suggest that the local geomagnetic disturbance contributes much less in modulating the cosmic ray flux.

  16. Essential properties of the Difference Method for the Search of the Anisotropy of the Primary Cosmic Radiation

    CERN Document Server

    Pavlyuchenko, V P; Nikolskaya, N M; Erlykin, A D

    2015-01-01

    The methodical properties of the original difference method for the search of the anisotropy at the knee region of the primary cosmic radiation energy spectrum are analyzed. The main feature of the suggested method is a study of the difference in the EAS characteristics in different directions but not their intensity. It is shown that the method is stable to the random experimental errors and allows to separate the anomalies related to the laboratory coordinate system from the anomalies in the celestial coordinates. The method uses multiple scattering of the charge particles in the Galaxy magnetic fields to study the whole celestial sphere including the regions outside of the line of sight of the installation.

  17. Cosmic Microwave Background Radiation Constraints on a Modified Chaplygin Gas Model

    Institute of Scientific and Technical Information of China (English)

    LIU Dao-Jun; LI Xin-Zhou

    2005-01-01

    @@ A modified Chaplygin gas model of unifying dark energy and dark matter with the exotic equation of state p = Bρ- A/ρα , which can also explain the recent expansion of the universe, is investigated by means of constraining the location of the peak of the cosmic microwave background radiation spectrum. We find that the result of CMBR measurements does not exclude the nonzero value of parameter B, but allows it in the range -0.35 (<~) B (<~) 0.025.

  18. Estimates of cosmic radiation dose received by aircrew of DCTA’s flight test special group

    Directory of Open Access Journals (Sweden)

    Cláudio Antonio Federico

    2010-08-01

    Full Text Available Aircraft crews are subjected to radiation doses of cosmic origin in the regular exercise of their functions. The present paper gives an estimate of typical doses received by crews of the Flight Test Special Group of DCTA (GEEV from July 2007 to November 2009. The dose estimates were performed using the CARI-6 and PCAIRE codes and were compared with each other and with values obtained by other authors in other regions of the globe, being analyzed from the standpoint of estimating radiobiological risk.

  19. Southern Hemisphere Measurement of the Anisotropy in the CosmicMicrowave Background Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Smoot, George F.; Lubin, Phil M.

    1979-06-01

    A recent measurement of the anisotropy in the Cosmic Background Radiation from the southern hemisphere (Lima, Peru) is essentially in agreement with previous measurements from the northern hemisphere. The net anisotropy can be described as a first order spherical harmonic (Doppler) anisotropy of amplitude 3.1 {+-} 0.4 m{sup o}K with a quadrupole anisotropy of less than 1 m{sup o}K. In addition, measurements of the linear polarization yield an upper limit of 1 m{sup o}K, or one part in 3000, at 95% C.L. for the amplitudes of any spherical harmonic through third order.

  20. Pulsar Wind Nebulae with Bow Shocks: Non-thermal Radiation and Cosmic Ray Leptons

    Science.gov (United States)

    Bykov, A. M.; Amato, E.; Petrov, A. E.; Krassilchtchikov, A. M.; Levenfish, K. P.

    2017-07-01

    Pulsars with high spin-down power produce relativistic winds radiating a non-negligible fraction of this power over the whole electromagnetic range from radio to gamma-rays in the pulsar wind nebulae (PWNe). The rest of the power is dissipated in the interactions of the PWNe with the ambient interstellar medium (ISM). Some of the PWNe are moving relative to the ambient ISM with supersonic speeds producing bow shocks. In this case, the ultrarelativistic particles accelerated at the termination surface of the pulsar wind may undergo reacceleration in the converging flow system formed by the plasma outflowing from the wind termination shock and the plasma inflowing from the bow shock. The presence of magnetic perturbations in the flow, produced by instabilities induced by the accelerated particles themselves, is essential for the process to work. A generic outcome of this type of reacceleration is the creation of particle distributions with very hard spectra, such as are indeed required to explain the observed spectra of synchrotron radiation with photon indices Γ≲ 1.5. The presence of this hard spectral component is specific to PWNe with bow shocks (BSPWNe). The accelerated particles, mainly electrons and positrons, may end up containing a substantial fraction of the shock ram pressure. In addition, for typical ISM and pulsar parameters, the e+ released by these systems in the Galaxy are numerous enough to contribute a substantial fraction of the positrons detected as cosmic ray (CR) particles above few tens of GeV and up to several hundred GeV. The escape of ultrarelativistic particles from a BSPWN—and hence, its appearance in the far-UV and X-ray bands—is determined by the relative directions of the interstellar magnetic field, the velocity of the astrosphere and the pulsar rotation axis. In this respect we review the observed appearance and multiwavelength spectra of three different types of BSPWNe: PSR J0437-4715, the Guitar and Lighthouse nebulae, and

  1. Estimating field scale root zone soil moisture using the cosmic-ray neutron probe

    Science.gov (United States)

    Peterson, A. M.; Helgason, W. D.; Ireson, A. M.

    2015-12-01

    Many practical hydrological, meteorological and agricultural management problems require estimates of soil moisture with an areal footprint equivalent to "field scale", integrated over the entire root zone. The cosmic-ray neutron probe is a promising instrument to provide field scale areal coverage, but these observations are shallow and require depth scaling in order to be considered representative of the entire root zone. A study to identify appropriate depth-scaling techniques was conducted at a grazing pasture site in central Saskatchewan, Canada over a two year period. Area-averaged soil moisture was assessed using a cosmic-ray neutron probe. Root zone soil moisture was measured at 21 locations within the 5002 m2 area, using a down-hole neutron probe. The cosmic-ray neutron probe was found to provide accurate estimates of field scale surface soil moisture, but accounted for less than 40 % of the seasonal change in root zone storage due to its shallow measurement depth. The root zone estimation methods evaluated were: (1) the coupling of the cosmic-ray neutron probe with a time stable neutron probe monitoring location, (2) coupling the cosmic-ray neutron probe with a representative landscape unit monitoring approach, and (3) convolution of the cosmic-ray neutron probe measurements with the exponential filter. The time stability method provided the best estimate of root zone soil moisture (RMSE = 0.004 cm3 cm-3), followed by the exponential filter (RMSE = 0.012 cm3 cm-3). The landscape unit approach, which required no calibration, had a negative bias but estimated the cumulative change in storage reasonably. The feasibility of applying these methods to field sites without existing instrumentation is discussed. It is concluded that the exponential filter method has the most potential for estimating root zone soil moisture from cosmic-ray neutron probe data.

  2. Study of the dosimetric characteristics of cosmic radiation at civil aviation altitudes

    CERN Document Server

    Ferrari, A; Rancati, T

    2002-01-01

    The dependence of the doses on solar activity for intermediate levels of the solar modulation parameter has been studied by means of simulations carried out by the Monte Carlo transport code FLUKA. The vertical cut-off rigidities investigated lie between 0.4 and 6.1 GV. The calculated results show that the linear dependence proposed in a previous work, for the effective dose rate as a function of the solar modulation parameter, can be considered as an acceptable approximation. In addition, some dosimetric characteristics of cosmic radiation and some properties of the dosemeters in use for monitoring in the cosmic ray environment have been analysed with a view to simplifying measurements. The depth-dose curves in the ICRU sphere and the response of a tissue-equivalent ionisation chamber have been determined by the FLUKA code for a number of cosmic ray spectra. On the basis of the calculated results, it is concluded that a value of the depth, d, which would make the ambient dose equivalent a conservative predic...

  3. Calibration approaches of cosmic-ray neutron sensing for soil moisture measurement in cropped fields

    Directory of Open Access Journals (Sweden)

    C. A. Rivera Villarreyes

    2013-04-01

    Full Text Available Measurement of soil moisture at the plot or hill-slope scale is an important link between local vadose-zone hydrology and catchment hydrology. This study evaluates the applicability of the cosmic-ray neutron sensing for soil moisture in cropped fields. Measurements of cosmic-ray neutrons (fast neutrons were performed at a lowland farmland in Bornim (Brandenburg, Germany cropped with sunflower and winter rye. Three field calibration approaches and four different ways of integration the soil moisture profile to an integral value for cosmic-ray neutron sensing were evaluated in this study. The cosmic-ray sensing (CRS probe was calibrated against a network of classical point-scale soil moisture measurements. A large CRS parameter variability was observed by choosing calibration periods within the different growing stages of sunflower and winter rye. Therefore, it was not possible to identify a single set of parameters perfectly estimating soil moisture for both sunflower and winter rye periods. On the other hand, CRS signal and its parameter variability could be understood by some crop characteristics and by predicting the attenuated neutrons by crop presence. This study proves the potentiality of the cosmic-ray neutron sensing at the field scale; however, its calibration needs to be adapted for seasonal vegetation in cropped fields.

  4. Propagation of Ultra High Energy Cosmic Rays in Extragalactic Magnetic Fields: A view from cosmological simulations

    CERN Document Server

    Hackstein, Stefan; Brueggen, Marcus; Sigl, Guenter; Dundovic, Andrej

    2016-01-01

    We use the CRPropa code to simulate the propagation of ultra high energy cosmic rays (with energy $\\geq 10^{18} \\rm eV$ and pure proton composition) through extragalactic magnetic fields that have been simulated with the cosmological ENZO code.We test both primordial and astrophysical magnetogenesis scenarios in order to investigate the impact of different magnetic field strengths in clusters, filaments and voids on the deflection of cosmic rays propagating across cosmological distances. We also study the effect of different source distributions of cosmic rays around simulated Milky-Way like observers. Our analysis shows that the arrival spectra and anisotropy of events are rather insensitive to the distribution of extragalactic magnetic fields, while they are more affected by the clustering of sources within a $\\sim 50$ Mpc distance to observers. Finally, we find that in order to reproduce the observed degree of isotropy of cosmic rays at $\\sim $ EeV energies, the average magnetic fields in cosmic voids must...

  5. On the radiative and thermodynamic properties of the cosmic radiations using COBE FIRAS instrument data: II. Extragalactic far infrared background radiation

    Science.gov (United States)

    Fisenko, Anatoliy I.; Lemberg, Vladimir

    2014-07-01

    Using formula to describe the average spectrum of the extragalactic far infrared background (FIRB) radiation measured by the COBE FIRAS instrument in the 0.15-2.4 THz frequency interval at mean temperature T=18.5 K, the radiative and thermodynamic properties, such as the total emissivity, total radiation power per unit area, total energy density, number density of photons, Helmholtz free energy density, entropy density, heat capacity at constant volume, and pressure are calculated. The value for the total intensity received in the 0.15-2.4 THz frequency interval is equal to 13.6 nW m-2 sr-1. This value is about 19.4 % of the total intensity expected from the energy released by stellar nucleosynthesis over cosmic history. The radiative and thermodynamic functions of the extragalactic far infrared background (FIRB) radiation are calculated at redshift z=1.5.

  6. Ultra high molecular weight polyethylene as a base material for shielding cosmic radiation in aerospace applications

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Marlon A., E-mail: marlon@ieav.cta.br [Instituto de Estudos Avancados (IEAv), Sao Jose dos Campos, SP (Brazil). Divisao de Fisica Aplicada; Goncalez, Odair L. [Instituto Tecnologico de Aeronautica (PG/CTE/ITA), Sao Jose dos Campos, SP (Brazil). Programa de Pos-Graduacao em Ciencias e Tecnologias Espaciais

    2013-07-01

    Materials with high content of hydrogen have good properties of shielding against the effects of cosmic rays (CR) because are less effective than materials with high nuclear masses in the generation of secondary radiation. Beside the Aluminum, Polyethylene has been used as a reference and as a base material for composites applied in structures and in shielding of ionizing radiation for aerospace applications. Ultra high molecular weight polyethylene (UHMWPE), pure and doped 10% by mass with cadmium chloride, had its shielding properties for CR evaluated in this paper. Methodology used was based in conventional radioactive sources employed on simple geometries experiments and then computational simulation for isotropic fluxes of cosmic-ray high energy particles. Transmission experiments were performed with a3.7GBq (100 mCi){sup 241}Am-Be neutron source and a set of conventional calibration gamma radiation sources. Samples were characterized according to their gamma total attenuation coefficients from 59 to 1,408 keV, dose deposition curve for {sup 60}Co gamma-rays, fast neutron transmission coefficient, generation and self-absorption of thermal neutrons as well as their generation of internal cascades of secondary electrons and gamma-rays by nuclear interactions of fast neutrons with shielding material. Main effects of the additive in the polyethylene base were the most effective removal of gamma radiation and of secondary electrons with energies below 200 keV, the reduction of the albedo as well as the thermal neutrons transmission. Dose reduction due to primary CR were not significant, since the largest contribution to the doses due to high energy ionizing particles transmitted and, also, due to secondary radiation with energy above 1 MeV produced in shielding. (author)

  7. Statistical Perturbation Theory of Cosmic Fields; 1, Basic Formalism and Second-order Theory

    CERN Document Server

    Matsubara, T

    2000-01-01

    We formulate a general method for perturbative evaluations of statistics of smoothed cosmic fields, which we call as ``Statistical Perturbation Theory''. The formalism is an extensive generalization of the method used by Matsubara (1994) who derived a weakly nonlinear formula of the genus statistic in a 3D density field. After describing the general method, we apply the formalism especially to analyses of more general genus statistics, level-crossing statistics, Minkowski functionals, and a density extrema statistic, regardless of the dimensions in which each statistic is defined. The relation between the Minkowski functionals and other geometrical statistics is clearly described. These examples are applied to some cosmic fields, including 3D density field, 3D velocity field, 2D projected density field, and 2D weak lensing field. The results are detailed for second order theory of the formalism. The reason why the genus curves etc. in CDM-like models exhibit smaller deviations from Gaussian predictions when t...

  8. Small-scale anisotropy of the cosmic background radiation and scattering by cloudy plasma

    CERN Document Server

    Peebles, P J E

    1998-01-01

    If the first stars formed soon after decoupling of baryons from the thermal cosmic background radiation (CBR), the radiation may have been last scattered in a cloudy plasma. We discuss the resulting small-scale anisotropy of the CBR in the limit where the plasma clouds are small compared to the mean distance between clouds along a line of sight. This complements the perturbative analysis valid for mildly nonlinear departures from homogeneity at last scattering. We conclude that reasonable choices for the cloud parameters imply CBR anisotropy consistent with the present experimental limits, in agreement with the perturbative approach. This means the remarkable isotropy of the CBR need not contradict the early small-scale structure formation predicted in some cosmogonies.

  9. Coherent dynamics of Rydberg atoms in cosmic-microwave-background radiation

    Science.gov (United States)

    Tscherbul, Timur V.; Brumer, Paul

    2014-01-01

    Rydberg atoms excited by cold blackbody radiation are shown to display long-lived quantum coherences on time scales of tens of picoseconds. By solving non-Markovian equations of motion with no free parameters we obtain the time evolution of the density matrix and demonstrate that the blackbody-induced temporal coherences manifest as slowly decaying (100 ps) quantum beats in time-resolved fluorescence. An analytic model shows the dependence of the coherent dynamics on the energy splitting between atomic eigenstates, transition dipole moments, and coherence time of the radiation. Experimental detection of the fluorescence signal from a trapped ensemble of 108 Rydberg atoms is discussed, but shown to be technically challenging at present, requiring cosmic-microwave-background amplification somewhat beyond current practice.

  10. Linear Energy Transfer (LET) spectra of cosmic radiation in low Earth orbit

    Science.gov (United States)

    Parnell, T. A.; Watts, J. W., Jr.; Akopova, A. B.; Magradze, N. V.; Dudkin, V. E.; Kovalev, E. E.; Potapov, Yu. V.; Benton, E. V.; Frank, A. L.; Benton, E. R.

    1995-01-01

    Integral linear energy transfer (LET) spectra of cosmic radiation (CR) particles were measured on five Cosmos series spacecraft in low Earth orbit (LEO). Particular emphasis is placed on results of the Cosmos 1887 biosatellite which carried a set of joint U.S.S.R.-U.S.A. radiation experiments involving passive detectors that included thermoluminescent detectors (TLD's), plastic nuclear track detectors (PNTD's), fission foils, nuclear photo-emulsions, etc. which were located both inside and outside the spacecraft. Measured LET spectra are compared with those theoretically calculated. Results show that there is some dependence of LET spectra on orbital parameters. The results are used to estimate the CR quality factor (QF) for the COSMOS 1887 mission.

  11. Cross-calibration of the Transition Radiation Detector of AMS-02 for an Energy Measurement of Cosmic-Ray Ions

    CERN Document Server

    Obermeier, Andreas

    2014-01-01

    Since May 2011 the AMS-02 experiment is installed on the International Space Station and is observing cosmic radiation. It consists of several state-of-the-art sub-detectors, which redundantly measure charge and energy of traversing particles. Due to the long exposure time of AMS-02 of many years the measurement of momentum for protons and ions is limited systematically by the spatial resolution and magnetic field strength of the silicon tracker. The maximum detectable rigidity for protons is about 1.8~TV, for helium about 3.6~TV. We investigate the possibility to extend the range of the energy measurement for heavy nuclei ($Z\\geq2$) with the transition radiation detector (TRD). The response function of the TRD shows a steep increase in signal from the level of ionization at a Lorentz factor $\\gamma$ of about 500 to $\\gamma\\approx20000$, where the transition radiation signal saturates. For heavy ions the signal fluctuations in the TRD are sufficiently small to allow an energy measurement with the TRD beyond t...

  12. The Cosmic Microwave Background Radiation-A Unique Window on the Early Universe

    Science.gov (United States)

    Hinshaw, Gary

    2010-01-01

    The cosmic microwave background radiation is the remnant heat from the Big Bang. It provides us with a unique probe of conditions in the early universe, long before any organized structures had yet formed. The anisotropy in the radiation's brightness yields important clues about primordial structure and additionally provides a wealth of information about the physics of the early universe. Within the framework of inflationary dark matter models, observations of the anisotropy on sub-degree angular scales reveals the signatures of acoustic oscillations of the photon-baryon fluid at a redshift of 11 00. Data from the first seven years of operation of the Wilkinson Microwave Anisotropy Probe (WMAP) satellite provide detailed full-sky maps of the cosmic microwave background temperature and polarization anisotropy. Together, the data provide a wealth of cosmological information, including the age of the universe, the epoch when the first stars formed, and the overall composition of baryonic matter, dark matter, and dark energy. The results also provide constraints on the period of inflationary expansion in the very first moments of time. WMAP, part of NASA's Explorers program, was launched on June 30, 2001. The WMAP satellite was produced in a partnership between the Goddard Space Flight Center and Princeton University. The WMAP team also includes researchers at the Johns Hopkins University; the Canadian Institute of Theoretical Astrophysics; University of Texas; Oxford University; University of Chicago; Brown University; University of British Columbia; and University of California, Los Angeles.

  13. Introducing CoDa (Cosmic Dawn): Radiation-Hydrodynamics of Galaxy Formation in the Early Universe

    Science.gov (United States)

    Ocvirk, Pierre; Gillet, Nicolas; Shapiro, Paul; Aubert, Dominique; Iliev, Ilian; Romain, Teyssier; Yepes, Gustavo; Choi, Jun-hwan; Sullivan, David; Knebe, Alexander; Gottloeber, Stefan; D'Aloisio, Anson; Park, Hyunbae; Hoffman, Yehuda

    2015-08-01

    CoDa (Cosmic Dawn) is the largest fully coupled radiation hydrodynamics simulation of the reionization of the local Universe to date. It was performed using RAMSES-CUDATON running on 8192 nodes (i.e. 8192 GPUs) on the titan supercomputer at Oak Ridge National Laboratory to simulate a 64 h-1Mpc side box down to z=4.23. In this simulation, reionization proceeds self-consistently, driven by stellar radiation. We compare the simulation's reionization history, ionizing flux density, the cosmic star formation history and the CMB Thompson scattering optical depth with their observational values. Luminosity functions are also in rather good agreement with high redshift observations, although very bright objects (MAB1600 gas filaments present a sheathed structure, with a hot envelope surrounding a cooler core. They are however not able to self-shield, while regions denser than 10^-4.5 H atoms per comoving h^-3cm^3 are. Haloes below M ˜ 3.10^9 M⊙ are severely affected by the expanding, rising UV background: their ISM is quickly photo-heated to temperatures above our star formation threshold and therefore stop forming stars after local reionization has occured. Overall, the haloes between 10^(10-11) M⊙ dominate the star formation budget of the box for most of the Epoch of Reionization. Several additional studies will follow, looking for instance at environmental effects on galaxy properties, and the regimes of accretion.

  14. Aircrew Exposure To Cosmic Radiation Evaluated By Means Of Several Methods; Results Obtained In 2006

    Science.gov (United States)

    Ploc, Ondřej; Spurný, František; Jadrníčková, Iva; Turek, Karel

    2008-08-01

    Routine evaluation of aircraft crew exposure to cosmic radiation in the Czech Republic is performed by means of calculation method. Measurements onboard aircraft work as a control tool of the routine method, as well as a possibility of comparison of results measured by means of several methods. The following methods were used in 2006: (1) mobile dosimetry unit (MDU) type Liulin—a spectrometer of energy deposited in Si-detector; (2) two types of LET spectrometers based on the chemically etched track detectors (TED); (3) two types of thermoluminescent detectors; and (4) two calculation methods. MDU represents currently one of the most reliable equipments for evaluation of the aircraft crew exposure to cosmic radiation. It is an active device which measures total energy depositions (Edep) in the semiconductor unit, and, after appropriate calibration, is able to give a separate estimation for non-neutron and neutron-like components of H*(10). This contribution consists mostly of results acquired by means of this equipment; measurements with passive detectors and calculations are mentioned because of comparison. Reasonably good agreement of all data sets could be stated.

  15. The Cosmic Microwave Background Radiation-A Unique Window on the Early Universe

    Science.gov (United States)

    Hinshaw, Gary

    2010-01-01

    The cosmic microwave background radiation is the remnant heat from the Big Bang. It provides us with a unique probe of conditions in the early universe, long before any organized structures had yet formed. The anisotropy in the radiation's brightness yields important clues about primordial structure and additionally provides a wealth of information about the physics of the early universe. Within the framework of inflationary dark matter models, observations of the anisotropy on sub-degree angular scales reveals the signatures of acoustic oscillations of the photon-baryon fluid at a redshift of 11 00. Data from the first seven years of operation of the Wilkinson Microwave Anisotropy Probe (WMAP) satellite provide detailed full-sky maps of the cosmic microwave background temperature and polarization anisotropy. Together, the data provide a wealth of cosmological information, including the age of the universe, the epoch when the first stars formed, and the overall composition of baryonic matter, dark matter, and dark energy. The results also provide constraints on the period of inflationary expansion in the very first moments of time. WMAP, part of NASA's Explorers program, was launched on June 30, 2001. The WMAP satellite was produced in a partnership between the Goddard Space Flight Center and Princeton University. The WMAP team also includes researchers at the Johns Hopkins University; the Canadian Institute of Theoretical Astrophysics; University of Texas; Oxford University; University of Chicago; Brown University; University of British Columbia; and University of California, Los Angeles.

  16. Wireless Phones Electromagnetic Field Radiation Exposure Assessment

    OpenAIRE

    A. D. Usman; W. F.W. Ahmad; M. Z. A. A. Kadir; M. Mokhtar

    2009-01-01

    Problem statement: Inadequate knowledge of electromagnetic field emitted by mobile phones and increased usage at close proximity, created a lot of skepticism and speculations among end users on its safety or otherwise. Approach: In this study, near field electromagnetic field radiation measurements were conducted on different brand of mobile phones in active mode using a tri-axis isotropic probe and electric field meter. Results: The highest electromagnetic field exposure was recorded when th...

  17. Lunar radiation environment and space weathering from the Cosmic Ray Telescope for the Effects of Radiation (CRaTER)

    Science.gov (United States)

    Schwadron, N. A.; Baker, T.; Blake, B.; Case, A. W.; Cooper, J. F.; Golightly, M.; Jordan, A.; Joyce, C.; Kasper, J.; Kozarev, K.; Mislinski, J.; Mazur, J.; Posner, A.; Rother, O.; Smith, S.; Spence, H. E.; Townsend, L. W.; Wilson, J.; Zeitlin, C.

    2012-03-01

    The Cosmic Ray Telescope for the Effects of Radiation (CRaTER) measures linear energy transfer by Galactic Cosmic Rays (GCRs) and Solar Energetic Particles (SEPs) on the Lunar Reconnaissance Orbiter (LRO) Mission in a circular, polar lunar orbit. GCR fluxes remain at the highest levels ever observed during the space age. One of the largest SEP events observed by CRaTER during the LRO mission occurred on June 7, 2011. We compare model predictions by the Earth-Moon-Mars Radiation Environment Module (EMMREM) for both dose rates from GCRs and SEPs during this event with results from CRaTER. We find agreement between these models and the CRaTER dose rates, which together demonstrate the accuracy of EMMREM, and its suitability for a real-time space weather system. We utilize CRaTER to test forecasts made by the Relativistic Electron Alert System for Exploration (REleASE), which successfully predicts the June 7th event. At the maximum CRaTER-observed GCR dose rate (˜11.7 cGy/yr where Gy is a unit indicating energy deposition per unit mass, 1 Gy = 1 J/kg), GCRs deposit ˜88 eV/molecule in water over 4 billion years, causing significant change in molecular composition and physical structure (e.g., density, color, crystallinity) of water ice, loss of molecular hydrogen, and production of more complex molecules linking carbon and other elements in the irradiated ice. This shows that space weathering by GCRs may be extremely important for chemical evolution of ice on the Moon. Thus, we show comprehensive observations from the CRaTER instrument on the Lunar Reconnaissance Orbiter that characterizes the radiation environment and space weathering on the Moon.

  18. Cosmic inflation in a landscape of heavy-fields

    CERN Document Server

    Cespedes, Sebastian

    2013-01-01

    Heavy isocurvature fields may have a strong influence on the low energy dynamics of curvature perturbations during inflation, as long as the inflationary trajectory becomes non-geodesic in the multi-field target space (the landscape). If fields orthogonal to the inflationary trajectory are sufficiently heavy, one expects a reliable effective field theory describing the low energy dynamics of curvature perturbations, with self-interactions determined by the shape of the inflationary trajectory. Previous work analyzing the role of heavy-fields during inflation have mostly focused in the effects on curvature perturbations due to a single heavy-field. In this article we extend the results of these works by studying models of inflation in which curvature perturbations interact with two heavy-fields. We show that the second heavy-field (orthogonal to both tangent and normal directions of the inflationary trajectory) may significantly affect the evolution of curvature modes. We compute the effective field theory for...

  19. High-impedance NbSi TES sensors for studying the cosmic microwave background radiation

    Science.gov (United States)

    Nones, C.; Marnieros, S.; Benoit, A.; Bergé, L.; Bideaud, A.; Camus, P.; Dumoulin, L.; Monfardini, A.; Rigaut, O.

    2012-12-01

    Precise measurements of the cosmic microwave background (CMB) are crucial in cosmology because any proposed model of the universe must account for the features of this radiation. The CMB has a thermal blackbody spectrum at a temperature of 2.725 K, i.e. the spectrum peaks in the microwave range frequency of 160.2 GHz, corresponding to a 1.9-mm wavelength. Of all CMB measurements that the scientific community has not yet been able to perform, the CMB B-mode polarization is probably the most challenging from the instrumental point of view. The signature of primordial gravitational waves, which give rise to a B-type polarization, is one of the goals in cosmology today and amongst the first objectives in the field. For this purpose, high-performance low-temperature bolometric cameras, made of thousands of pixels, are currently being developed by many groups, which will improve the sensitivity to B-mode CMB polarization by one or two orders of magnitude compared to the Planck satellite HFI detectors. We present here a new bolometer structure that is able to increase the pixel sensitivities and to simplify the fabrication procedure. This innovative device replaces delicate membrane-based structures and eliminates the mediation of phonons: the incoming energy is directly captured and measured in the electron bath of an appropriate sensor and the thermal decoupling is achieved via the intrinsic electron-phonon decoupling of the sensor at very low temperature. Reported results come from a 204-pixel array of NbxSi1-x transition edge sensors with a meander structure fabricated on a 2-inch silicon wafer using electron-beam co-evaporation and a cleanroom lithography process. To validate the application of this device to CMB measurements, we have performed an optical calibration of our sample in the focal plane of a dilution cryostat test bench. We have demonstrated a light absorption close to 20% and an optical noise equivalent power of about 7×10-16 W/√Hz, which is highly

  20. Cosmic radiation and airline pilots. Exposure patterns of Norwegian SAS-pilots 1960 to 1994

    Energy Technology Data Exchange (ETDEWEB)

    Tveten, U.

    1997-02-01

    The work which is presented in this report is part of a Norwegian epidemiological project, carried out in cooperation between Institutt for Energiteknikk (IFE), the Norwegian Cancer Registry (NCR) and the Norwegian Radiation Protection Authority (NRPA). The project has been partially financed by the Norwegian Research Council. Originating from the Norwegian project, a number of similar projects have been started or are in the planning stage in a number of European countries. The present report lays the ground for estimation of individual exposure histories to cosmic radiation of pilots employed by the Scandinavian Airline System (SAS). The results presented in this report (radiation doserates for the different types of aircraft in the different years) will, in a later stage of the project, be utilized to estimate the individual radiation exposure histories. The major sources of information used as basis for this work is the collection of old SAS time tables found in the SAS Museum at Fornebu Airport in Oslo, and information provided by members of the Pilots Associations.

  1. Cosmic radiation and airline pilots. Exposure patterns of Norwegian pilots flying aircraft not used by SAS

    Energy Technology Data Exchange (ETDEWEB)

    Tveten, U.

    1997-05-01

    The work which is presented in this report is part of a Norwegian epidemiological project, carried out in cooperation between Institutt for Energiteknikk (IFE), the Norwegian Cancer Registry (NCR) and the Norwegian Radiation Protection Authority (NRPA). The project has been partially financed by the Norwegian Research Council. Originating from the Norwegian project, a number of similar projects have been started or are in the planning stage in a number of European countries. The present report lays the ground for estimation of individual exposure histories to cosmic radiation of pilots flying a great diversity of different aircrafts. Aircrafts that appear in the time-tables of the Scandinavian Airline System (SAS) have been treated in an earlier report. The results presented in this report (radiation doserates for the different types of aircrafts in the different years) will, in a later stage of the project be utilized to estimate the individual radiation exposure histories. The major sources of information used as basis for the work in this report is information provided by several active pilots, members of the Pilots Associations, along with calculations performed using US Federal Aviation Administration`s computer code CARI-3N. 2 refs.

  2. Radiation Backgrounds at Cosmic Dawn: X-Rays from Compact Binaries

    CERN Document Server

    Madau, Piero

    2016-01-01

    We compute the expected X-ray diffuse background and radiative feedback on the intergalactic medium (IGM) from X-ray binaries prior and during the epoch of reionization. The cosmic evolution of compact binaries is followed using a population synthesis technique that treats separately neutron stars and black hole binaries in different spectral states and is calibrated to reproduce the observed X-ray properties of galaxies at z6. Radiative transfer effects modulate the background spectrum, which shows a characteristic peak between 1 and 2 keV. While the filtering of X-ray radiation through the IGM slightly increases the mean excess energy per photoionization, it also weakens the radiation intensity below 1 keV, lowering the mean photoionization and heating rates. Numerical integration of the rate and energy equations shows that the contribution of X-ray binaries to the ionization of the bulk IGM is negligible, with the electron fraction never exceeding 1%. Direct HeI photoionizations are the main source of IGM ...

  3. Cosmic inflation in a landscape of heavy-fields

    Science.gov (United States)

    Céspedes, Sebastián; Palma, Gonzalo A.

    2013-10-01

    Heavy isocurvature fields may have a strong influence on the low energy dynamics of curvature perturbations during inflation, as long as the inflationary trajectory becomes non-geodesic in the multi-field target space (the landscape). If fields orthogonal to the inflationary trajectory are sufficiently heavy, one expects a reliable effective field theory describing the low energy dynamics of curvature perturbations, with self-interactions determined by the shape of the inflationary trajectory. Previous work analyzing the role of heavy-fields during inflation have mostly focused in the effects on curvature perturbations due to a single heavy-field. In this article we extend the results of these works by studying models of inflation in which curvature perturbations interact with two heavy-fields. We show that the second heavy-field (orthogonal to both tangent and normal directions of the inflationary trajectory) may significantly affect the evolution of curvature modes. We compute the effective field theory for the low energy curvature perturbations obtained by integrating out the two heavy-fields and show that the presence of the second heavy-field implies the existence of additional self-interactions not accounted for in the single heavy-field case. We conclude that future observations will be able to constrain the number of heavy fields interacting with curvature perturbations.

  4. From the Gyration of Electrons to Cosmic Magnetic Fields

    Science.gov (United States)

    Wang, Xia-Wei

    2010-01-01

    Employing Bohr's quantum theory, the author deduces three limits, which correspond to the magnetic fields of white dwarfs, neutron stars and the strongest in the universe. The author discusses the possible origins of magnetic fields due to collapse of stars, which produces a magnetic field of 10[superscript 8] T. Although the complete analysis…

  5. Dynamic Cosmic Strings, 1

    CERN Document Server

    Sjodin, K R P; Vickers, J A

    2001-01-01

    The field equations for a time dependent cylindrical cosmic string coupled togravity are reformulated in terms of geometrical variables defined on a2+1-dimensional spacetime by using the method of Geroch decomposition. Unlikethe 4-dimensional spacetime the reduced case is asymptotically flat. Anumerical method for solving the field equations which involves conformallycompactifying the space and including null infinity as part of the grid isdescribed. It is shown that the code reproduces the results of a number ofvacuum solutions with one or two degrees of freedom. In the final section theinteraction between the cosmic string and a pulse of gravitational radiation isbriefly described. This will be fully analysed in the sequel.

  6. Radiative corrections from heavy fast-roll fields during inflation

    Energy Technology Data Exchange (ETDEWEB)

    Jain, Rajeev Kumar; Sandora, McCullen; Sloth, Martin S. [CP" 3-Origins, Center for Cosmology and Particle Physics Phenomenology,University of Southern Denmark,Campusvej 55, 5230 Odense M (Denmark)

    2015-06-09

    We investigate radiative corrections to the inflaton potential from heavy fields undergoing a fast-roll phase transition. We find that a logarithmic one-loop correction to the inflaton potential involving this field can induce a temporary running of the spectral index. The induced running can be a short burst of strong running, which may be related to the observed anomalies on large scales in the cosmic microwave spectrum, or extend over many e-folds, sustaining an effectively constant running to be searched for in the future. We implement this in a general class of models, where effects are mediated through a heavy messenger field sitting in its minimum. Interestingly, within the present framework it is a generic outcome that a large running implies a small field model with a vanishing tensor-to-scalar ratio, circumventing the normal expectation that small field models typically lead to an unobservably small running of the spectral index. An observable level of tensor modes can also be accommodated, but, surprisingly, this requires running to be induced by a curvaton. If upcoming observations are consistent with a small tensor-to-scalar ratio as predicted by small field models of inflation, then the present study serves as an explicit example contrary to the general expectation that the running will be unobservable.

  7. Effects of the galactic magnetic field upon large scale anisotropies of extragalactic cosmic rays

    Energy Technology Data Exchange (ETDEWEB)

    Harari, D.; Mollerach, S.; Roulet, E., E-mail: harari@cab.cnea.gov.ar, E-mail: mollerach@cab.cnea.gov.ar, E-mail: roulet@cab.cnea.gov.ar [CONICET, Centro Atómico Bariloche, Bustillo 9500, 8400 Bariloche (Argentina)

    2010-11-01

    The large scale pattern in the arrival directions of extragalactic cosmic rays that reach the Earth is different from that of the flux arriving to the halo of the Galaxy as a result of the propagation through the galactic magnetic field. Two different effects are relevant in this process: deflections of trajectories and (de)acceleration by the electric field component due to the galactic rotation. The deflection of the cosmic ray trajectories makes the flux intensity arriving to the halo from some direction to appear reaching the Earth from another direction. This applies to any intrinsic anisotropy in the extragalactic distribution or, even in the absence of intrinsic anisotropies, to the dipolar Compton-Getting anisotropy induced when the observer is moving with respect to the cosmic rays rest frame. For an observer moving with the solar system, cosmic rays traveling through far away regions of the Galaxy also experience an electric force coming from the relative motion (due to the rotation of the Galaxy) of the local system in which the field can be considered as being purely magnetic. This produces small changes in the particles momentum that can originate large scale anisotropies even for an isotropic extragalactic flux.

  8. Primordial magnetic field from non-inflationary cosmic expansion in Horava-Lifshitz gravity

    CERN Document Server

    Maeda, Satoshi; Shiromizu, Tetsuya

    2009-01-01

    The origin of large-scale magnetic field in the universe is one of the greatest mysteries in modern cosmology. We present a new mechanism for generation of large-scale magnetic field, based on the power-counting renormalizable theory of gravitation recently proposed by Horava. Contrary to the usual case in general relativity, the U(1) gauge symmetry of a Maxwell action in this theory permits terms breaking conformal invariance in the ultraviolet. Moreover, for high frequency modes, the anisotropic scaling intrinsic to the theory inevitably makes the sound horizon far outside the Hubble horizon. Consequently, non-inflationary cosmic expansion in the early universe naturally generates super-horizon quantum fluctuations of the magnetic field. Specializing our consideration to the case with the dynamical critical exponent $z=3$, we show an explicit set of parameters for which (i) the amplitude of generated magnetic field is large enough as a seed for the dynamo mechanism; (ii) backreaction to the cosmic expansion...

  9. Probing Solar Magnetic Field with the "Cosmic-Ray Shadow" of the Sun

    CERN Document Server

    Amenomori, M; Chen, D; Chen, T L; Chen, W Y; Cui, S W; Danzengluobu,; Ding, L K; Feng, C F; Feng, Zhaoyang; Feng, Z Y; Gou, Q B; Guo, Y Q; Hakamada, K; He, H H; He, Z T; Hibino, K; Hotta, N; Hu, Haibing; Hu, H B; Huang, J; Jia, H Y; Jiang, L; Kajino, F; Kasahara, K; Katayose, Y; Kato, C; Kawata, K; Labaciren,; Le, G M; Li, A F; Li, H J; Li, W J; Liu, C; Liu, J S; Liu, M Y; Lu, H; Meng, X R; Mizutani, K; Munakata, K; Nanjo, H; Nishizawa, M; Ohnishi, M; Ohta, I; Onuma, H; Ozawa, S; Qian, X L; Qu, X B; Saito, T; Saito, T Y; Sakata, M; Sako, T K; Shao, J; Shibata, M; Shiomi, A; Shirai, T; Sugimoto, H; Takita, M; Tan, Y H; Tateyama, N; Torii, S; Tsuchiya, H; Udo, S; Wang, H; Wu, H R; Xue, L; Yamamoto, Y; Yang, Z; Yasue, S; Yuan, A F; Yuda, T; Zhai, L M; Zhang, H M; Zhang, J L; Zhang, X Y; Zhang, Y; Zhang, Yi; Zhang, Ying; Zhaxisangzhu,; Zhou, X X

    2013-01-01

    We report on a clear solar-cycle variation of the Sun's shadow in the 10 TeV cosmic-ray flux observed by the Tibet air shower array during a full solar cycle from 1996 to 2009. In order to clarify the physical implications of the observed solar cycle variation, we develop numerical simulations of the Sun's shadow, using the Potential Field Source Surface (PFSS) model and the Current Sheet Source Surface (CSSS) model for the coronal magnetic field. We find that the intensity deficit in the simulated Sun's shadow is very sensitive to the coronal magnetic field structure, and the observed variation of the Sun's shadow is better reproduced by the CSSS model. This is the first successful attempt to evaluate the coronal magnetic field models by using the Sun's shadow observed in the TeV cosmic-ray flux.

  10. Calibration of solid state nuclear track detectors at high energy ion beams for cosmic radiation measurements: HAMLET results

    Energy Technology Data Exchange (ETDEWEB)

    Szabo, J., E-mail: julianna.szabo@energia.mta.hu [Hungarian Academy of Sciences, Centre for Energy Research, Konkoly Thege Miklos ut 29-33, 1525 Budapest 114, P.O. Box 49 (Hungary); Palfalvi, J.K. [Hungarian Academy of Sciences, Centre for Energy Research, Konkoly Thege Miklos ut 29-33, 1525 Budapest 114, P.O. Box 49 (Hungary)

    2012-12-01

    The MATROSHKA experiments and the related HAMLET project funded by the European Commission aimed to study the dose burden of the crew working on the International Space Station (ISS). During these experiments a human phantom equipped with several thousands of radiation detectors was exposed to cosmic rays inside and outside the ISS. Besides the measurements realized in Earth orbit, the HAMLET project included also a ground-based program of calibration and intercomparison of the different detectors applied by the participating groups using high-energy ion beams. The Space Dosimetry Group of the Centre for Energy Research (formerly Atomic Energy Research Institute) participated in these experiments with passive solid state nuclear track detectors (SSNTDs). The paper presents the results of the calibration experiments performed in the years 2008-2011 at the Heavy Ion Medical Accelerator (HIMAC) of the National Institute of Radiological Sciences (NIRS), Chiba, Japan. The data obtained serve as update and improvement for the previous calibration curves which are necessary for the evaluation of the SSNTDs exposed in unknown space radiation fields.

  11. A Generalization of Gauge Symmetry, Fourth-Order Gauge Field Equations and Accelerated Cosmic-Expansion

    OpenAIRE

    2014-01-01

    A generalization of the usual gauge symmetry leads to fourth-order gauge field equations, which imply a new constant force independent of distances. The force associated with the new $U_1$ gauge symmetry is repulsive among baryons. Such a constant force based on baryon charge conservation gives a field-theoretic understanding of the accelerated cosmic-expansion in the observable portion of the universe dominated by baryon galaxies. In consistent with all conservation laws and known forces, a ...

  12. Probing Atmospheric Electric Fields in Thunderstorms through Radio Emission from Cosmic-Ray-Induced Air Showers

    CERN Document Server

    Schellart, P; Buitink, S; Corstanje, A; Enriquez, J E; Falcke, H; Hörandel, J R; Nelles, A; Rachen, J P; Rossetto, L; Scholten, O; ter Veen, S; Thoudam, S; Ebert, U; Koehn, C; Rutjes, C; Alexov, A; Anderson, J M; Avruch, I M; Bentum, M J; Bernardi, G; Best, P; Bonafede, A; Breitling, F; Broderick, J W; Brüggen, M; Butcher, H R; Ciardi, B; de Geus, E; de Vos, M; Duscha, S; Eislöffel, J; Fallows, R A; Frieswijk, W; Garrett, M A; Grießmeier, J; Gunst, A W; Heald, G; Hessels, J W T; Hoeft, M; Holties, H A; Juette, E; Kondratiev, V I; Kuniyoshi, M; Kuper, G; Mann, G; McFadden, R; McKay-Bukowski, D; McKean, J P; Mevius, M; Moldon, J; Norden, M J; Orru, E; Paas, H; Pandey-Pommier, M; Pizzo, R; Polatidis, A G; Reich, W; Röttgering, H; Scaife, A M M; Schwarz, D J; Serylak, M; Smirnov, O; Steinmetz, M; Swinbank, J; Tagger, M; Tasse, C; Toribio, M C; van Weeren, R J; Vermeulen, R; Vocks, C; Wise, M W; Wucknitz, O; Zarka, P

    2015-01-01

    We present measurements of radio emission from cosmic ray air showers that took place during thunderstorms. The intensity and polarization patterns of these air showers are radically different from those measured during fair-weather conditions. With the use of a simple two-layer model for the atmospheric electric field, these patterns can be well reproduced by state-of-the-art simulation codes. This in turn provides a novel way to study atmospheric electric fields.

  13. Bremsstrahlung Energy Losses for Cosmic Ray Electrons and Positrons

    CERN Document Server

    Widom, A; Srivastava, R

    2015-01-01

    Recently cosmic ray electrons and positrons, i.e. cosmic ray charged leptons, have been observed. To understand the distances from our solar system to the sources of such lepton cosmic rays, it is important to understand energy losses from cosmic electrodynamic fields. Energy losses for ultra-relativistic electrons and/or positrons due to classical electrodynamic bremsstrahlung are computed. The energy losses considered are (i) due to Thompson scattering from fluctuating electromagnetic fields in the background cosmic thermal black body radiation and (ii) due to the synchrotron radiation losses from quasi-static domains of cosmic magnetic fields. For distances to sources of galactic length proportions, the lepton cosmic ray energy must be lass than about a TeV.

  14. New Measurements of the Cosmic Background Radiation Temperature at3.3 mm Wavelength

    Energy Technology Data Exchange (ETDEWEB)

    Witebsky, C.; Smoot, G.; De Amici, G.; Friedman, S.D.

    1986-02-01

    We have measured the temperature of the cosmic background radiation (CBR) at 3.3 mm wavelength in 1982, 1983, and 1984 as part of a larger project to determine the CBR temperature at five wavelengths from 12 cm to 3.3 mm (Smoot et al. 1985). The 3.3-mm measurements yield a brightness temperature of 2.57 K with a 1{sigma} uncertainty of 20.12 K. This paper describes the instrument, the measurement techniques, and the data-analysis procedures used. Our result is in good agreement with recent measurements at comparable wavelengths by Meyer and Jura (1985) and by Peterson, Richards, and Timusk (1985), but it disagrees with the temperatures reported by Woody and Richards (1981).

  15. Measurement of the large-scale anisotropy of the cosmic background radiation at 3mm

    Energy Technology Data Exchange (ETDEWEB)

    Epstein, G.L.

    1983-12-01

    A balloon-borne differential radiometer has measured the large-scale anisotropy of the cosmic background radiation (CBR) with high sensitivity. The antenna temperature dipole anistropy at 90 GHz (3 mm wavelength) is 2.82 +- 0.19 mK, corresponding to a thermodynamic anistropy of 3.48 +- mK for a 2.7 K blackbody CBR. The dipole direction, 11.3 +- 0.1 hours right ascension and -5.7/sup 0/ +- 1.8/sup 0/ declination, agrees well with measurements at other frequencies. Calibration error dominates magnitude uncertainty, with statistical errors on dipole terms being under 0.1 mK. No significant quadrupole power is found, placing a 90% confidence-level upper limit of 0.27 mK on the RMS thermodynamic quadrupolar anistropy. 22 figures, 17 tables.

  16. Hawking radiation via tunneling from the spacetime of a spinning cosmic string black holes

    CERN Document Server

    Jusufi, Kimet

    2015-01-01

    In this paper, we study Hawking radiation as a massless particles tunneling process across the event horizon from the Schwarzschild and Reissner-Nordstr\\"om black holes pierced by an infinitely long spinning cosmic string and a global monopole. Applying the WKB approximation and using a generalized Painlev\\'e line element for stationary axisymmetric spacetimes, also by taking into account that the ADM mass of the black hole decreases due to the presence of topological defects, it is shown that the Hawking temperature remains unchanged for these black holes. The tunneling of charged massive particles from Reissner-Nordstr\\"om black holes is also studied, in both cases the tunneling rate is related to the change of the Bekenstein-Hawking entropy. The results extend the work of Parikh and Wilczek and are consistent with an underlying unitary theory.

  17. A Flat Universe from High-Resolution Maps of the Cosmic MicrowaveBackground Radiation

    Energy Technology Data Exchange (ETDEWEB)

    de Bernardis, P.; Ade, P.A.R.; Bock, J.J.; Bond, J.R.; Borrill,J.; Boscaleri, A.; Coble, K.; Crill, B.P.; De Gasperis, G.; Farese, P.C.; Ferreira, P.G.; Ganga, K.; Giacometti, M.; Hivon, E.; Hristov, V.V.; Iacoangeli, A.; Jaffe, A.H.; Lange, A.E.; Martinis, L.; Masi, S.; Mason,P.; Mauskopf, P.D.; Melchiorri, A.; Miglio, L.; Montroy, T.; Netterfield,C.B.; Pascale, E.; Piacentini, F.; Pogosyan, D.; Prunet, S.; Rao, S.; Romeo, G.; Ruhl, J.E.; Scaramuzzi, F.; Sforna, D.; Vittorio, N.

    2000-04-28

    The blackbody radiation left over from the Big Bang has been transformed by the expansion of the Universe into the nearly isotropic 2.73 K Cosmic Microwave Background. Tiny inhomogeneities in the early Universe left their imprint on the microwave background in the form of small anisotropies in its temperature. These anisotropies contain information about basic cosmological parameters, particularly the total energy density and curvature of the universe. Here we report the first images of resolved structure in the microwave background anisotropies over a significant part of the sky. Maps at four frequencies clearly distinguish the microwave background from foreground emission. We compute the angular power spectrum of the microwave background, and find a peak at Legendre multipole {ell}{sub peak} = (197 {+-} 6), with an amplitude DT{sub 200} = (69 {+-} 8){mu}K. This is consistent with that expected for cold dark matter models in a flat (euclidean) Universe, as favored by standard inflationary scenarios.

  18. Studies about space radiation promote new fields in radiation biology.

    Science.gov (United States)

    Ohnishi, Takeo; Takahashi, Akihisa; Ohnishi, Ken

    2002-12-01

    Astronauts are constantly exposed to space radiation of various types of energy with a low dose-rate during long-term stays in space. Therefore, it is important to determine correctly the biological effects of space radiation on human health. Studies about biological the effects at a low dose and a low dose-rate include various aspects of microbeams, bystander effects, radioadaptive responses and hormesis which are important fields in radiation biology. In addition, space radiations contain high linear energy transfer (LET) particles. In particular, neutrons may cause reverse effectiveness at a low dose-rate in comparison to ionizing radiation. We are also interested in p53-centered signal transduction pathways involved in the cell cycle, DNA repair and apoptosis induced by space radiations. We must also study whether the relative biological effectiveness (RBE) of space radiation is affected by microgravity which is another typical component in space. To confirm this, we must prepare centrifuge systems in an International Space Station (ISS). In addition, we must prepare many types of equipment for space experiments in an ISS, because we cannot use conventional equipment from our laboratories. Furthermore, the research for space radiation might give us valuable information about the birth and evolution of life on the Earth. We can also realize the importance of preventing the ozone layer from depletion by the use of exposure equipment to sunlight in an ISS. For these reasons, we desire to educate space researchers of the next generation based on the consideration of the preservation of the Earth from research about space radiation.

  19. On climate response to changes in the cosmic ray flux and radiative budget

    CERN Document Server

    Shaviv, N J

    2004-01-01

    We examine the results linking cosmic ray flux (CRF) variations to global climate change. We then proceed to study various periods over which there are estimates for the radiative forcing, temperature change and CRF variations relative to today. These include the Phanerozoic as a whole, the Cretaceous, the Eocene, the Last Glacial Maximum, the 20th century, as well as the 11-yr solar cycle. This enables us to place quantitative limits on climate sensitivity to both changes in the CRF, Phi_CR, and the radiative budget, F, under equilibrium. Under the assumption that the CRF is indeed a climate driver, we find that the sensitivity to CRF variations is consistently fitted with mu := -Phi_0 (dT_global/ d Phi_CR) = 6.5 +/- 2.5 K (where Phi_0 is the CR energy flux today). Additionally, the sensitivity to radiative forcing changes is lambda := dT_global/ dF_0 = 0.35 +/- 0.09 K/(W/m^2), at the current temperature, while its temperature derivative is negligible with d lambda / dT_0 = 0.01 +/- 0.03 1/(W/m^2). If the ob...

  20. Cosmic radiation and mortality from cancer among male German airline pilots: extended cohort follow-up.

    Science.gov (United States)

    Hammer, Gaël Paul; Blettner, Maria; Langner, Ingo; Zeeb, Hajo

    2012-06-01

    Commercial airline pilots are exposed to cosmic radiation and other specific occupational factors, potentially leading to increased cancer mortality. This was analysed in a cohort of 6,000 German cockpit crew members. A mortality follow-up for the years 1960-2004 was performed and occupational and dosimetry data were collected for this period. 405 deaths, including 127 cancer deaths, occurred in the cohort. The mortality from all causes and all cancers was significantly lower than in the German population. Total mortality decreased with increasing radiation doses (rate ratio (RR) per 10 mSv: 0.85, 95 % CI: 0.79, 0.93), contrasting with a non-significant increase of cancer mortality (RR per 10 mSv: 1.05, 95 % CI: 0.91, 1.20), which was restricted to the group of cancers not categorized as radiogenic in categorical analyses. While the total and cancer mortality of cockpit crew is low, a positive trend of all cancer with radiation dose is observed. Incomplete adjustment for age, other exposures correlated with duration of employment and a healthy worker survivor effect may contribute to this finding. More information is expected from a pooled analysis of updated international aircrew studies.

  1. Primordial Gravitational Waves and Rescattered Electromagnetic Radiation in the Cosmic Microwave Background

    Science.gov (United States)

    Kim, Dong-Hoon; Trippe, Sascha

    2016-10-01

    Understanding the interaction of primordial gravitational waves (GWs) with the Cosmic Microwave Background (CMB) plasma is important for observational cosmology. In this article, we provide an analysis of an apparently as-yet-overlooked effect. We consider a single free electric charge and suppose that it can be agitated by primordial GWs propagating through the CMB plasma, resulting in periodic, regular motion along particular directions. Light reflected by the charge will be partially polarized, and this will imprint a characteristic pattern on the CMB. We study this effect by considering a simple model in which anisotropic incident electromagnetic (EM) radiation is rescattered by a charge sitting in spacetime perturbed by GWs, and becomes polarized. As the charge is driven to move along particular directions, we calculate its dipole moment to determine the leading-order rescattered EM radiation. The Stokes parameters of the rescattered radiation exhibit a net linear polarization. We investigate how this polarization effect can be schematically represented out of the Stokes parameters. We work out the representations of gradient modes (E-modes) and curl modes (B-modes) to produce polarization maps. Although the polarization effect results from GWs, we find that its representations, the E- and B-modes, do not practically reflect the GW properties such as strain amplitude, frequency, and polarization states.

  2. Epidemiological investigations of aircrew: an occupational group with low-level cosmic radiation exposure.

    Science.gov (United States)

    Zeeb, Hajo; Hammer, Gaël P; Blettner, Maria

    2012-03-01

    Aircrew and passengers are exposed to low-level cosmic ionising radiation. Annual effective doses for flight crew have been estimated to be in the order of 2-5 mSv and can attain 75 mSv at career end. Epidemiological studies in this occupational group have been conducted over the last 15-20 years, usually with a focus on radiation-associated cancer. These studies are summarised in this note. Overall cancer risk was not elevated in most studies and subpopulations analysed, while malignant melanoma, other skin cancers and breast cancer in female aircrew have shown elevated incidence, with lesser risk elevations in terms of mortality. In some studies, including the large German cohort, brain cancer risk appears elevated. Cardiovascular mortality risks were generally very low. Dose information for pilots was usually derived from calculation procedures based on routine licence information, types of aircraft and routes/hours flown, but not on direct measurements. However, dose estimates have shown high validity when compared with measured values. No clear-cut dose-response patterns pointing to a higher risk for those with higher cumulative doses were found. Studies on other health outcomes have shown mixed results. Overall, aircrew are a highly selected group with many specific characteristics and exposures that might also influence cancers or other health outcomes. Radiation-associated health effects have not been clearly established in the studies available so far.

  3. Effects of Nuclear Cross Sections at Different Energies on Space Radiation Exposure from Galactic Cosmic Rays

    Science.gov (United States)

    Li, Zi-Wei; Adams, James H., Jr.

    2007-01-01

    Space radiation from galactic cosmic rays (GCR) is a major hazard to space crews, especially in long duration human space explorations. For this reason, they will be protected by radiation shielding that fragments the GCR heavy ions. Here we investigate how sensitive the crew's radiation exposure is to nuclear fragmentation cross sections at different energies. We find that in deep space cross sections between about 0.2 and 1.2 GeV/u have the strongest effect on dose equivalent behind shielding in solar minimum GCR environments, and cross sections between about 0.6 and 1.7 GeV/u are the most important at solar maximum'. On the other hand, at the location of the International Space Station, cross sections at_higher -energies, between about 0.6 and 1.7 GeV /u at solar minimum and between about 1.7 and 3.4 GeV/u'at,solar maximum, are the most important This is. due-to the average geomagnetic cutoff for the ISS orbit. We also show the effect of uncertainties in the fragmentation cross sections on the elemental energy spectra behind shielding. These results help to focus the studies of fragmentation cross sections on the proper energy range in order to improve our predictions of crew exposures.

  4. The simulation of TGF origin in lightning leader electric fields by cosmic ray shower electrons

    Science.gov (United States)

    Connell, P. H.; Atri, D.

    2015-12-01

    With the TGF simulation package LEPTRACK we can easily create all kinds of electric field geometries and electron flux fields to simulate Relativistic Runaway Electron Avalanches - it is script driven, with the details of high energy scattering physics hidden from the user, and an easily accessible output database for each particle created or scattered. We will show the results of simulating a realistic scenario of TGF origin based on cosmic ray shower electron flux fields in the neighbourhood of electric field geometries expected around lightning leader tips. Electron fluxes are derived from simulations using the CORSIKA cosmic ray simulation package and leader electric field geometry from current models. Presuming a TGF observed at orbital altitudes must come from a lightning leader pointing "upwards", and that cosmic rays enter at angles pointing "downwards" to "horizontal", we will show which combinations allow the electron flux to curve into the compact electric field of the leader and gain sufficient acceleration to create a TGF photon flux observable in orbit.

  5. Radiative Corrections from Heavy Fast-Roll Fields during Inflation

    CERN Document Server

    Jain, Rajeev Kumar; Sloth, Martin S

    2015-01-01

    We investigate radiative corrections to the inflaton potential from heavy fields undergoing a fast-roll phase transition. We find that a logarithmic one-loop correction to the inflaton potential involving this field can induce a temporary running of the spectral index. The induced running can be a short burst of strong running, which may be related to the observed anomalies on large scales in the cosmic microwave spectrum, or extend over many e-folds, sustaining an effectively constant running to be searched for in the future. We implement this in a general class of models, where effects are mediated through a heavy messenger field sitting in its minimum. Interestingly, within the present framework it is a generic outcome that a large running implies a small field model with a vanishing tensor-to-scalar ratio, circumventing the normal expectation that small field models typically lead to an unobservable small running of the spectral index. An observable level of tensor modes can also be accommodated, but, sur...

  6. Effects of magnetic fields on the cosmic-ray ionization of molecular cloud cores

    CERN Document Server

    Padovani, Marco

    2011-01-01

    Low-energy cosmic rays are the dominant source of ionization for molecular cloud cores. The ionization fraction, in turn, controls the coupling of the magnetic field to the gas and hence the dynamical evolution of the cores. The purpose of this work is to compute the attenuation of the cosmic-ray flux rate in a cloud core taking into account magnetic focusing, magnetic mirroring, and all relevant energy loss processes. We adopt a standard cloud model characterized by a mass-to-flux ratio supercritical by a factor of about 2 to describe the density and magnetic field distribution of a low-mass starless core, and we follow the propagation of cosmic rays through the core along flux tubes enclosing different amount of mass. We then extend our analysis to cores with different mass-to-flux ratios. We find that mirroring always dominates over focusing, implying a reduction of the cosmic-ray ionization rate by a factor of about 2-3 over most of a solar-mass core with respect to the value in the intercloud medium outs...

  7. A microscopic, non-equilibrium, statistical field theory for cosmic structure formation

    Science.gov (United States)

    Bartelmann, Matthias; Fabis, Felix; Berg, Daniel; Kozlikin, Elena; Lilow, Robert; Viermann, Celia

    2016-04-01

    Building upon the recent pioneering work by Mazenko and by Das and Mazenko, we develop a microscopic, non-equilibrium, statistical field theory for initially correlated canonical ensembles of classical microscopic particles obeying Hamiltonian dynamics. Our primary target is cosmic structure formation, where initial Gaussian correlations in phase space are believed to be set by inflation. We give an exact expression for the generating functional of this theory and work out suitable approximations. We specify the initial correlations by a power spectrum and derive general expressions for the correlators of the density and the response field. We derive simple closed expressions for the lowest-order contributions to the nonlinear cosmological power spectrum, valid for arbitrary wave numbers. We further calculate the bispectrum expected in this theory within these approximations and the power spectrum of cosmic density fluctuations to first order in the gravitational interaction, using a recent improvement of the Zel’dovich approximation. We show that, with a modification motivated by the adhesion approximation, the nonlinear growth of the density power spectrum found in numerical simulations of cosmic structure evolution is reproduced well to redshift zero and for arbitrary wave numbers even within first-order perturbation theory. Our results present the first fully analytic calculation of the nonlinear power spectrum of cosmic structures.

  8. Latitudinal Dependence of Cosmic Rays Modulation at 1 AU and Interplanetary-Magnetic-Field Polar Correction

    CERN Document Server

    Bobik, P; Boschini, M J; Consolandi, C; Della Torre, S; Gervasi, M; Grandi, D; Kudela, K; Pensotti, S; Rancoita, P G; Rozza, D; Tacconi, M

    2012-01-01

    The cosmic rays differential intensity inside the heliosphere, for energy below 30 GeV/nuc, depends on solar activity and interplanetary magnetic field polarity. This variation, termed solar modulation, is described using a 2-D (radius and colatitude) Monte Carlo approach for solving the Parker transport equation that includes diffusion, convection, magnetic drift and adiabatic energy loss. Since the whole transport is strongly related to the interplanetary magnetic field (IMF) structure, a better understanding of his description is needed in order to reproduce the cosmic rays intensity at the Earth, as well as outside the ecliptic plane. In this work an interplanetary magnetic field model including the standard description on ecliptic region and a polar correction is presented. This treatment of the IMF, implemented in the HelMod Monte Carlo code (version 2.0), was used to determine the effects on the differential intensity of Proton at 1\\,AU and allowed one to investigate how latitudinal gradients of proton...

  9. Electro- and Magnetostatics of a Cosmic Pseudoscalar Field Coupled to Electromagnetism

    Energy Technology Data Exchange (ETDEWEB)

    Caldwell, Robert; Motta, Leonardo dias da [Department of Physics and Astronomy, Dartmouth College, 6127 Wilder Laboratory, Hanover, NH 03755 (United States)

    2009-10-15

    A spatially-inhomogeneous, time-varying cosmic pseudoscalar field coupled to electromagnetism via the Chern-Simons invariant F{sub m}u{sub n}uF-tilde{sup m}u{sup n}u acts as a new source of charge and current for electromagnetic fields. We evaluate the magnetic field produced by a static electric charge, and the electric field resulting from a stationary current. We show that the pseudoscalar exerts a torque on objects carrying both electric charge and a magnetic moment.

  10. Scalar-field quintessence by cosmic shear: CFHT data analysis and forecasts for DUNE

    CERN Document Server

    Schimd, C; Schimd, Carlo; Tereno, Ismael

    2006-01-01

    A light scalar field, minimally or not-minimally coupled to the metric field, is a well-defined candidate for the dark energy, overcoming the coincidence problem intrinsic to the cosmological constant and avoiding the difficulties of parameterizations. We present a general description of the weak gravitational lensing valid for every metric theory of gravity, including vector and tensor perturbations for a non-flat spatial metric. Based on this description, we investigate two minimally-coupled scalar field quintessence models using VIRMOS-Descart and CFHTLS cosmic shear data, and forecast the constraints for the proposed space-borne wide-field imager DUNE.

  11. Symmetry breaking and cosmic acceleration in scalar field models

    CERN Document Server

    Sadjadi, M Mohseni; Sepangi, H R

    2015-01-01

    We study the possible role of symmetry breaking in the onset of the acceleration of the Universe in a scalar field dark energy model. We propose a new scenario in which acceleration of the Universe is driven by a positive potential produced by means of symmetry breaking.

  12. Cosmic Dawn (CoDa): the First Radiation-Hydrodynamics Simulation of Reionization and Galaxy Formation in the Local Universe

    CERN Document Server

    Ocvirk, Pierre; Shapiro, Paul R; Aubert, Dominique; Iliev, Ilian T; Teyssier, Romain; Yepes, Gustavo; Choi, Jun-Hwan; Sullivan, David; Knebe, Alexander; Gottloeber, Stefan; D'Aloisio, Anson; Park, Hyunbae; Hoffman, Yehuda; Stranex, Timothy

    2015-01-01

    Cosmic reionization by starlight from early galaxies affected their evolution, thereby impacting reionization, itself. Star formation suppression, for example, may explain the observed underabundance of Local Group dwarfs relative to N-body predictions for Cold Dark Matter. Reionization modelling requires simulating volumes large enough ~(100 Mpc)^3 to sample reionization "patchiness", while resolving millions of galaxy sources above ~10^8 Msun, combining gravitational and gas dynamics with radiative transfer. Modelling the Local Group requires initial cosmological density fluctuations pre-selected to form the well-known structures of the local universe today. Cosmic Dawn ("CoDa") is the first such fully-coupled, radiation-hydrodynamics simulation of reionization of the local universe. Our new hybrid CPU-GPU code, RAMSES-CUDATON, performs hundreds of radiative transfer and ionization rate-solver timesteps on the GPUs for each hydro-gravity timestep on the CPUs. CoDa simulated (91 Mpc)^3 with 4096^3 particles ...

  13. Single particle effects, Biostack, and risk evaluation - Studies on the radiation risk from Galactic cosmic rays

    Science.gov (United States)

    Curtis, Stanley B.

    1993-01-01

    The possible health risks posed by Galactic cosmic rays, especially the possible heightened cancer risk, are examined. The results of the Biostack studies of the biological effects of high-energy cosmic rays are discussed. The biological mechanisms involved in possible harm due to cosmic rays are considered.

  14. Cosmic-ray neutron transport at a forest field site

    DEFF Research Database (Denmark)

    Andreasen, Mie; Jensen, Karsten Høgh; Desilets, Darin

    2017-01-01

    parameters describing the subsurface to match measured height profiles and time series of thermal and epithermal neutron intensities at a field site in Denmark. Overall, modeled thermal and epithermal neutron intensities are in satisfactory agreement with measurements; however, the choice of forest canopy...... conceptualization is found to be significant. Modeling results show that the effect of canopy interception, soil chemistry and dry bulk density of litter and mineral soil on neutron intensity is small. On the other hand, the neutron intensity decreases significantly with added litter-layer thickness, especially...... for epithermal neutron energies. Forest biomass also has a significant influence on the neutron intensity height profiles at the examined field site, altering both the shape of the profiles and the ground-level thermal-to-epithermal neutron ratio. This ratio increases with increasing amounts of biomass...

  15. The role of cosmic rays on magnetic field diffusion and the formation of protostellar discs

    CERN Document Server

    Padovani, Marco; Hennebelle, Patrick; Commerçon, Benoît; Joos, Marc

    2014-01-01

    The formation of protostellar discs is severely hampered by magnetic braking, as long as magnetic fields remain frozen in the gas. The latter condition depends on the levels of ionisation that characterise the innermost regions of a collapsing cloud. The chemistry of dense cloud cores and, in particular, the ionisation fraction is largely controlled by cosmic rays. The aim of this paper is to evaluate whether the attenuation of the flux of cosmic rays expected in the regions around a forming protostar is sufficient to decouple the field from the gas, thereby influencing the formation of centrifugally supported disc. We adopted the method developed in a former study to compute the attenuation of the cosmic-ray flux as a function of the column density and the field strength in clouds threaded by poloidal and toroidal magnetic fields. We applied this formalism to models of low- and high-mass star formation extracted from numerical simulations of gravitational collapse that include rotation and turbulence. For ea...

  16. Detection of cosmic gamma-rays using a heliostat field

    Science.gov (United States)

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

    2001-08-01

    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.

  17. Galactic synchrotron radiation from radio to microwaves, and its relation to cosmic-ray propagation models: past, present and future

    Science.gov (United States)

    Orlando, Elena

    2016-04-01

    Galactic synchrotron radiation observed from radio to microwaves is produced by cosmic-ray (CR) electrons propagating in magnetic fields (B-fields). The low-frequency foreground component separated maps by WMAP and Planck depend on the assumed synchrotron spectrum. The synchrotron spectrum varies for different line of sights as a result of changes on the CR spectrum due to propagation effects and source distributions. Our present knowledge of the CR spectrum at different locations in the Galaxy is not sufficient to distinguish various possibilities in the modeling. As a consequence uncertainties on synchrotron emission models complicate the foreground component separation analysis with Planck and future microwave telescopes. Hence, any advancement in synchrotron modeling is important for separating the different foreground components.The first step towards a more comprehensive understanding of degeneracy and correlation among the synchrotron model parameters is outlined in our Strong et al. 2011 and Orlando et al. 2013 papers. In the latter the conclusion was that CR spectrum, propagation models, B-fields, and foreground component separation analysis need to be studied simultaneously in order to properly obtain and interpret the synchrotron foreground. Indeed for the officially released Planck maps, we use only the best spectral model from our above paper for the component separation analysis.Here we present a collections of our latest results on synchrotron, CRs and B-fields in the context of CR propagation, showing also our recent work on B-fields within the Planck Collaboration. We underline also the importance of using the constraints on CRs that we obtain from gamma ray observations. Methods and perspectives for further studies on the synchrotron foreground will be addressed.

  18. An Instrument for Investigation of the Cosmic Microwave Background Radiation at Intermediate Angular Scales

    Science.gov (United States)

    Wollack, E. J.; Devlin, M. J.; Jarosik, N.; Netterfield, C. B.; Page, L.; Wilkinson, D.

    1997-02-01

    We describe an off-axis microwave telescope for observations of the anisotropy in the cosmic microwave background (CMB) radiation on angular scales between 0.5d and 3°. The receiver utilizes cryogenic high electron mobility transistor (HEMT) amplifiers and detects the total power in multiple 3 GHz wide channels. Both frequency and polarization information are recorded allowing discrimination between CMB radiation and potential foreground sources and allowing checks for systematic effects. The instrumental radiometric offset is small (~1 mK). Data are taken by rapidly sampling while sweeping the beam many beamwidths across the sky. After detection, a spatio-temporal filter is formed in software that optimizes the sensitivity in a multipole band in the presence of atmospheric fluctuations. Observations were made from Saskatoon, Saskatchewan (SK), Canada, during the winter of 1993 with six channels between 27.6 and 34.0 GHz, in 1994 with 12 channels between 27.6 and 44.1 GHz, and in 1995 with six channels between 38.2 and 44.1 GHz. The performance of the instrument and assessment of the atmospheric noise at this site are discussed.

  19. Cosmic Rays at Earth

    Science.gov (United States)

    Grieder, P. K. F.

    In 1912 Victor Franz Hess made the revolutionary discovery that ionizing radiation is incident upon the Earth from outer space. He showed with ground-based and balloon-borne detectors that the intensity of the radiation did not change significantly between day and night. Consequently, the sun could not be regarded as the sources of this radiation and the question of its origin remained unanswered. Today, almost one hundred years later the question of the origin of the cosmic radiation still remains a mystery. Hess' discovery has given an enormous impetus to large areas of science, in particular to physics, and has played a major role in the formation of our current understanding of universal evolution. For example, the development of new fields of research such as elementary particle physics, modern astrophysics and cosmology are direct consequences of this discovery. Over the years the field of cosmic ray research has evolved in various directions: Firstly, the field of particle physics that was initiated by the discovery of many so-called elementary particles in the cosmic radiation. There is a strong trend from the accelerator physics community to reenter the field of cosmic ray physics, now under the name of astroparticle physics. Secondly, an important branch of cosmic ray physics that has rapidly evolved in conjunction with space exploration concerns the low energy portion of the cosmic ray spectrum. Thirdly, the branch of research that is concerned with the origin, acceleration and propagation of the cosmic radiation represents a great challenge for astrophysics, astronomy and cosmology. Presently very popular fields of research have rapidly evolved, such as high-energy gamma ray and neutrino astronomy. In addition, high-energy neutrino astronomy may soon initiate as a likely spin-off neutrino tomography of the Earth and thus open a unique new branch of geophysical research of the interior of the Earth. Finally, of considerable interest are the biological

  20. Study of inflationary generalized cosmic Chaplygin gas for standard and tachyon scalar fields

    Energy Technology Data Exchange (ETDEWEB)

    Sharif, M.; Saleem, Rabia [University of the Punjab, Department of Mathematics, Lahore (Pakistan)

    2014-07-15

    We consider an inflationary universe model in the context of the generalized cosmic Chaplygin gas by taking the matter field as standard and tachyon scalar fields. We evaluate the corresponding scalar fields and scalar potentials during the intermediate and logamediate inflationary regimes by modifying the first Friedmann equation. In each case, we evaluate the number of e-folds, scalar as well as tensor power spectra, scalar spectral index, and the important observational parameter, the tensor-scalar ratio in terms of inflation. The graphical behavior of this parameter shows that the model remains incompatible with WMAP7 and Planck observational data in each case. (orig.)

  1. Study of Inflationary Generalized Cosmic Chaplygin Gas for Standard and Tachyon Scalar Fields

    CERN Document Server

    Sharif, M

    2014-01-01

    We consider an inflationary universe model in the context of generalized cosmic Chaplygin gas by taking matter field as standard and tachyon scalar fields. We evaluate the corresponding scalar fields and scalar potentials during intermediate and logamediate inflationary regimes by modifying the first Friedmann equation. In each case, we evaluate the number of e-folds, scalar as well as tensor power spectra, scalar spectral index and important observational parameter, i.e., tensor-scalar ratio in terms of inflatons. The graphical behavior of this parameter shows that the model remains incompatible with WMAP7 and Planck observational data in each case.

  2. Neutrinos from Cosmic Accelerators including Magnetic Field and Flavor Effects

    Directory of Open Access Journals (Sweden)

    Walter Winter

    2012-01-01

    Full Text Available We review the particle physics ingredients affecting the normalization, shape, and flavor composition of astrophysical neutrinos fluxes, such as different production modes, magnetic field effects on the secondaries (muons, pions, and kaons, and flavor mixing, where we focus on pγ interactions. We also discuss the interplay with neutrino propagation and detection, including the possibility to detect flavor and its application in particle physics, and the use of the Glashow resonance to discriminate pγ from pp interactions in the source. We illustrate the implications on fluxes and flavor composition with two different models: (1 the target photon spectrum is dominated by synchrotron emission of coaccelerated electrons and (2 the target photon spectrum follows the observed photon spectrum of gamma-ray bursts. In the latter case, the multimessenger extrapolation from the gamma-ray fluence to the expected neutrino flux is highlighted.

  3. Cosmic magnetic fields and dark energy in extended electromagnetism

    Energy Technology Data Exchange (ETDEWEB)

    Beltran Jimenez, Jose; Maroto, Antonio L, E-mail: Jose.Beltran@unige.ch, E-mail: maroto@fis.ucm.es [Departamento de Fisica Teorica, Universidad Complutense de Madrid, 28040, Madrid (Spain)

    2011-09-22

    We discuss an extended version of electromagnetism in which the usual gauge fixing term is promoted into a physical contribution that introduces a new scalar state in the theory. This new state can be generated from vacuum quantum fluctuations during an inflationary era and, on super-Hubble scales, gives rise to an effective cosmological constant. The value of such a cosmological constant coincides with the one inferred from observations as long as inflation took place at the electroweak scale. On the other hand, the new state also generates an effective electric charge density on sub-Hubble scales that produces both vorticity and magnetic fields with coherent lengths as large as the present Hubble horizon.

  4. Weak cosmic censorship, dyonic Kerr-Newman black holes and Dirac fields

    Science.gov (United States)

    Zsolt Tóth, Gábor

    2016-06-01

    It was investigated recently, with the aim of testing the weak cosmic censorship conjecture, whether an extremal Kerr black hole can be converted into a naked singularity by interaction with a massless classical Dirac test field, and it was found that this is possible. We generalize this result to electrically and magnetically charged rotating extremal black holes (i.e. extremal dyonic Kerr-Newman black holes) and massive Dirac test fields, allowing magnetically or electrically uncharged or nonrotating black holes and the massless Dirac field as special cases. We show that the possibility of the conversion is a direct consequence of the fact that the Einstein-Hilbert energy-momentum tensor of the classical Dirac field does not satisfy the null energy condition, and is therefore not in contradiction with the weak cosmic censorship conjecture. We give a derivation of the absence of superradiance of the Dirac field without making use of the complete separability of the Dirac equation in the dyonic Kerr-Newman background, and we determine the range of superradiant frequencies of the scalar field. The range of frequencies of the Dirac field that can be used to convert a black hole into a naked singularity partially coincides with the superradiant range of the scalar field. We apply horizon-penetrating coordinates, as our arguments involve calculating quantities at the event horizon. We describe the separation of variables for the Dirac equation in these coordinates, although we mostly avoid using it.

  5. Special electromagnetic fields in type D vacuum space-times and cosmic censorship

    CERN Document Server

    Düztaş, Koray

    2016-01-01

    We consider two test, null electromagnetic fields aligned with the two repeated principal null directions of the type D background, and a test, non-null field special in the sense that the principal null directions of the electromagnetic field lie along the repeated principal null directions of the space-time. We prove the existence of the non-null field in type D background. This field behaves as $1/r^2$ and its contribution to the energy and angular momentum fluxes vanishes in Kerr background. For that reason the special non-null field does not lead to any perturbation of black hole parameters of mass and angular momentum; thus it does not challenge the cosmic censorship conjecture. The conjecture also stays valid in the interaction of an extremal or a nearly extremal Kerr black hole with the null field directed along $n^a$. However, the null field directed along $l^a$ leads to a generic violation of cosmic censorship conjecture.

  6. Accounting for Cosmic Variance in Studies of Gravitationally-Lensed High-Redshift Galaxies in the Hubble Frontier Field Clusters

    CERN Document Server

    Robertson, Brant E; Dunlop, James S; McLure, Ross J; Stark, Daniel P; McLeod, Derek

    2014-01-01

    Strong gravitational lensing provides a powerful means for studying faint galaxies in the distant universe. By magnifying the apparent brightness of background sources, massive clusters enable the detection of galaxies fainter than the usual sensitivity limit for blank fields. However, this gain in effective sensitivity comes at the cost of a reduced survey volume and, in this {\\it Letter}, we demonstrate there is an associated increase in the cosmic variance uncertainty. As an example, we show that the cosmic variance uncertainty of the high redshift population viewed through the Hubble Space Telescope Frontier Field cluster Abell 2744 increases from ~35% at redshift z~7 to >~65% at z~10. Previous studies of high redshift galaxies identified in the Frontier Fields have underestimated the cosmic variance uncertainty that will affect the ultimate constraints on both the faint end slope of the high-redshift luminosity function and the cosmic star formation rate density, key goals of the Frontier Field program.

  7. Accounting for Cosmic Variance in Studies of Gravitationally Lensed High-redshift Galaxies in the Hubble Frontier Field Clusters

    Science.gov (United States)

    Robertson, Brant E.; Ellis, Richard S.; Dunlop, James S.; McLure, Ross J.; Stark, Dan P.; McLeod, Derek

    2014-12-01

    Strong gravitational lensing provides a powerful means for studying faint galaxies in the distant universe. By magnifying the apparent brightness of background sources, massive clusters enable the detection of galaxies fainter than the usual sensitivity limit for blank fields. However, this gain in effective sensitivity comes at the cost of a reduced survey volume and, in this Letter, we demonstrate that there is an associated increase in the cosmic variance uncertainty. As an example, we show that the cosmic variance uncertainty of the high-redshift population viewed through the Hubble Space Telescope Frontier Field cluster Abell 2744 increases from ~35% at redshift z ~ 7 to >~ 65% at z ~ 10. Previous studies of high-redshift galaxies identified in the Frontier Fields have underestimated the cosmic variance uncertainty that will affect the ultimate constraints on both the faint-end slope of the high-redshift luminosity function and the cosmic star formation rate density, key goals of the Frontier Field program.

  8. Chiral-field microwave antennas (Chiral microwave near fields for far-field radiation)

    CERN Document Server

    Kamenetskii, E O; Shavit, R

    2015-01-01

    In a single-element structure we obtain a radiation pattern with a squint due to chiral microwave near fields originated from a magnetostatic-mode ferrite disk. At the magnetostatic resonances, one has strong subwavelength localization of energy of microwave radiation. Magnetostatic oscillations in a thin ferrite disk are characterized by unique topological properties: the Poynting-vector vortices and the field helicity. The chiral-topology near fields allow obtaining unique phase structure distribution for far-field microwave radiation.

  9. Cosmic-Ray Moisture Probe on North Slope of Alaska Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Desilets, Darin [Hydroinnova LLC

    2016-06-15

    In September of 2014 a wide-area snow monitoring device was installed at the U.S. Department of Energy (DOE)’s Barrow, Alaska Atmospheric Radiation Measurement (ARM) Climate Research Facility site. The device is special in that it uses measurements of cosmic-ray neutrons as a proxy for snow water equivalent (SWE) depth. A unique characteristic of the technology is that it integrates over a wide area (as much as 40 ha), in contrast to conventional ground-based technologies, which essentially give point samples. Conventional point-scale technologies are problematic in the Arctic, both because extreme weather conditions are taxing on equipment, and because point measurements can fail to accurately characterize the average SWE over a larger area, even when excellent precision is obtained. The sensor installed in Barrow is, by far, the northernmost of a constellation of sites that makeup the U.S. COsmic ray Soil Moisture Observing System (COSMOS). The sensor is used for SWE measurements in winter and soil moisture measurements in summer. The ability of this type of sensor to operate in the Arctic had not been verified until now. The cosmic-ray sensor was installed on a tripod located approximately 150 m south of the ARM User Facility (Figure 1), and within boundaries of land managed by the ARM Facility. The sensor consists of both “bare” and “moderated” channels, where the moderated channel is the primary output used to calculate SWE. A QDL2100 data logger with pressure sensor was located inside of the User Facility, and a Campbell CS215 temperature and humidity sensor was attached to a rail on the upper deck of the User Facility, to enable near-real-time absolute humidity corrections to the data. The cosmic-ray sensors are connected to the data logger using an armored Cat5e cable that lies on top of the tundra. Data are retrieved hourly via Iridium satellite link.

  10. Bound and Radiation Fields in Rindler Frame

    CERN Document Server

    Hirayama, T

    2001-01-01

    Energy-momentum tensor of Li\\'enard-Wiechert field is split into bound and emitted parts in Rindler frame, by generalizing the reasoning of Teitelboim used in inertial frame. Our discussion proceeds with the the notion of ``energy'' defined with respect to the Killing vector field attached to the frame. We obtain the ``radiation formula in Rindler frame''(Rindler version of Larmor formula) and it is found that the radiation power is proportional to the square of ``acceleration $\\alpha^\\mu$ of the charge relative to the Rindler frame''. This result makes us split the Li\\'enard-Wiechert field into the part $\\tII$ which is linear in $\\alpha^\\mu$ and the part $\\tI$ which is independent of $\\alpha^\\mu$, and by using them, we split the energy-momentum tensor into two parts. We find that these are properly interpreted as the emitted and bound parts of the tensor in Rindler frame. In our identification of radiation, a charge does not radiate not only in the case where the charge is fixed to the Rindler frame, but als...

  11. Formation of secondary radiation fields at NICA

    Science.gov (United States)

    Timoshenko, G.; Paraipan, M.

    2009-09-01

    The crucial points of a radiation shielding design for a relativistic heavy ion accelerator are the source term problem, neutron fluence and dose attenuation characteristics of the shielding. Simulations of the radiation shielding for JINR's Nuclotron-Based Ion Facility (NICA) project were carried out using the GEANT4 code. Some regularities in the secondary neutron field generation at the 4.5 GeV/n uranium beam interaction with thick targets are discussed. Neutron attenuation by the ordinary concrete shielding of NICA was considered as well.

  12. Cosmic expansion history from SNe Ia data via information field theory: the charm code

    Science.gov (United States)

    Porqueres, Natàlia; Enßlin, Torsten A.; Greiner, Maksim; Böhm, Vanessa; Dorn, Sebastian; Ruiz-Lapuente, Pilar; Manrique, Alberto

    2017-03-01

    We present charm (cosmic history agnostic reconstruction method), a novel inference algorithm that reconstructs the cosmic expansion history as encoded in the Hubble parameter H(z) from SNe Ia data. The novelty of the approach lies in the usage of information field theory, a statistical field theory that is very well suited for the construction of optimal signal recovery algorithms. The charm algorithm infers non-parametrically s(a) = ln(ρ(a) /ρcrit0), the density evolution which determines H(z), without assuming an analytical form of ρ(a) but only its smoothness with the scale factor a = (1 + z)-1. The inference problem of recovering the signal s(a) from the data is formulated in a fully Bayesian way. In detail, we have rewritten the signal as the sum of a background cosmology and a perturbation. This allows us to determine the maximum a posteriory estimate of the signal by an iterative Wiener filter method. Applying charm to the Union2.1 supernova compilation, we have recovered a cosmic expansion history that is fully compatible with the standard ΛCDM cosmological expansion history with parameter values consistent with the results of the Planck mission.

  13. Cosmology with hybrid expansion law: scalar field reconstruction of cosmic history and observational constraints

    Energy Technology Data Exchange (ETDEWEB)

    Akarsu, Özgür [Department of Physics, Koç University, 34450 Sariyer, İstanbul (Turkey); Kumar, Suresh [Department of Mathematics, BITS Pilani, Pilani Campus, Rajasthan-333031 (India); Myrzakulov, R.; Sami, M. [Centre of Theoretical Physics, Jamia Millia Islamia, New Delhi-110025 (India); Xu, Lixin, E-mail: oakarsu@ku.edu.tr, E-mail: sukuyd@gmail.com, E-mail: rmyrzakulov@gmail.com, E-mail: samijamia@gmail.com, E-mail: lxxu@dlut.edu.cn [Institute of Theoretical Physics, Dalian University of Technology, Dalian, 116024 (China)

    2014-01-01

    In this paper, we consider a simple form of expansion history of Universe referred to as the hybrid expansion law - a product of power-law and exponential type of functions. The ansatz by construction mimics the power-law and de Sitter cosmologies as special cases but also provides an elegant description of the transition from deceleration to cosmic acceleration. We point out the Brans-Dicke realization of the cosmic history under consideration. We construct potentials for quintessence, phantom and tachyon fields, which can give rise to the hybrid expansion law in general relativity. We investigate observational constraints on the model with hybrid expansion law applied to late time acceleration as well as to early Universe a la nucleosynthesis.

  14. The unified first law in 'cosmic triad' vector field scenario

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Yi, E-mail: zhangyia@cqupt.edu.cn [College of Mathematics and Physics, Chongqing University of Posts and Telecommunications, Chongqing 400065 (China); Department of Astronomy, Beijing Normal University, Beijing 100875 (China); Gong Yungui, E-mail: gongyg@cqupt.edu.cn [College of Mathematics and Physics, Chongqing University of Posts and Telecommunications, Chongqing 400065 (China); Zhu Zonghong, E-mail: zhuzh@bnu.edu.cn [Department of Astronomy, Beijing Normal University, Beijing 100875 (China)

    2011-06-13

    In this Letter, we try to apply the unified first law to the 'cosmic triad' vector field scenario both in the minimal coupling case and in the non-minimal coupling case. After transferring the non-minimally coupling action in the Jordan frame to the Einstein frame, the correct dynamical equation (Friedmann equation) is gotten in a thermal equilibrium process by using the already existing entropy while the entropy in the non-minimal coupled 'cosmic triad' scenario has not been derived. And after transferring the variables back to the Jordan frame, the corresponding Friedmann equation is demonstrated to be correct. For complete arguments, we also calculate the related Misner-Sharp energy in the Jordan and Einstein frames.

  15. Electric field of thunderclouds and cosmic rays: evidence for acceleration of particles (runaway electrons)

    CERN Document Server

    Khaerdinov, N S; Petkov, V B; 12th International Conference on Atmospheric Electricity

    2004-01-01

    We present the data on correlations of the intensity of the soft component of cosmic rays with the local electric field of the near-earth atmosphere during thunderstorm periods at the Baksan Valley (North Caucasus, 1700 m a. s. l.). The large-area array for studying the extensive air showers of cosmic rays is used as a particle detector. An electric field meter of the "electric mill" type (rain-protected) is mounted on the roof of the building in the center of this array. The data were obtained in the summer seasons of 2000-2002. We observe strong enhancements of the soft component intensity before some lightning strokes. At the same time, the analysis of the regression curve "intensity versus field" discovers a bump at the field sign that is opposite to the field sign corresponding to acceleration of electrons. It is interpreted as a signature of runaway electrons from the region of the strong field (with opposite sign) overhead.

  16. A generalization of gauge symmetry, fourth-order gauge field equations and accelerated cosmic expansion

    Science.gov (United States)

    Hsu, Jong-Ping

    2014-02-01

    A generalization of the usual gauge symmetry leads to fourth-order gauge field equations, which imply a new constant force independent of distances. The force associated with the new U1 gauge symmetry is repulsive among baryons. Such a constant force based on baryon charge conservation gives a field-theoretic understanding of the accelerated cosmic expansion in the observable portion of the universe dominated by baryon galaxies. In consistent with all conservation laws and known forces, a simple rotating "dumbbell model" of the universe is briefly discussed.

  17. A Generalization of Gauge Symmetry, Fourth-Order Gauge Field Equations and Accelerated Cosmic-Expansion

    CERN Document Server

    Hsu, Jong-Ping

    2014-01-01

    A generalization of the usual gauge symmetry leads to fourth-order gauge field equations, which imply a new constant force independent of distances. The force associated with the new $U_1$ gauge symmetry is repulsive among baryons. Such a constant force based on baryon charge conservation gives a field-theoretic understanding of the accelerated cosmic-expansion in the observable portion of the universe dominated by baryon galaxies. In consistent with all conservation laws and known forces, a simple rotating `dumbbell model' of the universe is briefly discussed.

  18. Precise Mapping of the Magnetic Field in the CMS Barrel Yoke using Cosmic Rays

    CERN Document Server

    Chatrchyan, S; Sirunyan, A M; Adam, W; Arnold, B; Bergauer, H; Bergauer, T; Dragicevic, M; Eichberger, M; Erö, J; Friedl, M; Frühwirth, R; Ghete, V M; Hammer, J; Hänsel, S; Hoch, M; Hörmann, N; Hrubec, J; Jeitler, M; Kasieczka, G; Kastner, K; Krammer, M; Liko, D; Magrans de Abril, I; Mikulec, I; Mittermayr, F; Neuherz, B; Oberegger, M; Padrta, M; Pernicka, M; Rohringer, H; Schmid, S; Schöfbeck, R; Schreiner, T; Stark, R; Steininger, H; Strauss, J; Taurok, A; Teischinger, F; Themel, T; Uhl, D; Wagner, P; Waltenberger, W; Walzel, G; Widl, E; Wulz, C E; Chekhovsky, V; Dvornikov, O; Emeliantchik, I; Litomin, A; Makarenko, V; Marfin, I; Mossolov, V; Shumeiko, N; Solin, A; Stefanovitch, R; Suarez Gonzalez, J; Tikhonov, A; Fedorov, A; Karneyeu, A; Korzhik, M; Panov, V; Zuyeuski, R; Kuchinsky, P; Beaumont, W; Benucci, L; Cardaci, M; De Wolf, E A; Delmeire, E; Druzhkin, D; Hashemi, M; Janssen, X; Maes, T; Mucibello, L; Ochesanu, S; Rougny, R; Selvaggi, M; Van Haevermaet, H; Van Mechelen, P; Van Remortel, N; Adler, V; Beauceron, S; Blyweert, S; D'Hondt, J; De Weirdt, S; Devroede, O; Heyninck, J; Kalogeropoulos, A; Maes, J; Maes, M; Mozer, M U; Tavernier, S; Van Doninck, W; Van Mulders, P; Villella, I; Bouhali, O; Chabert, E C; Charaf, O; Clerbaux, B; De Lentdecker, G; Dero, V; Elgammal, S; Gay, A P R; Hammad, G H; Marage, P E; Rugovac, S; Vander Velde, C; Vanlaer, P; Wickens, J; Grunewald, M; Klein, B; Marinov, A; Ryckbosch, D; Thyssen, F; Tytgat, M; Vanelderen, L; Verwilligen, P; Basegmez, S; Bruno, G; Caudron, J; Delaere, C; Demin, P; Favart, D; Giammanco, A; Grégoire, G; Lemaitre, V; Militaru, O; Ovyn, S; Piotrzkowski, K; Quertenmont, L; Schul, N; Beliy, N; Daubie, E; Alves, G A; Pol, M E; Souza, M H G; Carvalho, W; De Jesus Damiao, D; De Oliveira Martins, C; Fonseca De Souza, S; Mundim, L; Oguri, V; Santoro, A; Silva Do Amaral, S M; Sznajder, A; Fernandez Perez Tomei, T R; Ferreira Dias, M A; Gregores, E M; Novaes, S F; Abadjiev, K; Anguelov, T; Damgov, J; Darmenov, N; Dimitrov, L; Genchev, V; Iaydjiev, P; Piperov, S; Stoykova, S; Sultanov, G; Trayanov, R; Vankov, I; Dimitrov, A; Dyulendarova, M; Kozhuharov, V; Litov, L; Marinova, E; Mateev, M; Pavlov, B; Petkov, P; Toteva, Z; Chen, G M; Chen, H S; Guan, W; Jiang, C H; Liang, D; Liu, B; Meng, X; Tao, J; Wang, J; Wang, Z; Xue, Z; Zhang, Z; Ban, Y; Cai, J; Ge, Y; Guo, S; Hu, Z; Mao, Y; Qian, S J; Teng, H; Zhu, B; Avila, C; Baquero Ruiz, M; Carrillo Montoya, C A; Gomez, A; Gomez Moreno, B; Ocampo Rios, A A; Osorio Oliveros, A F; Reyes Romero, D; Sanabria, J C; Godinovic, N; Lelas, K; Plestina, R; Polic, D; Puljak, I; Antunovic, Z; Dzelalija, M; Brigljevic, V; Duric, S; Kadija, K; Morovic, S; Fereos, R; Galanti, M; Mousa, J; Papadakis, A; Ptochos, F; Razis, P A; Tsiakkouri, D; Zinonos, Z; Hektor, A; Kadastik, M; Kannike, K; Müntel, M; Raidal, M; Rebane, L; Anttila, E; Czellar, S; Härkönen, J; Heikkinen, A; Karimäki, V; Kinnunen, R; Klem, J; Kortelainen, M J; Lampén, T; Lassila-Perini, K; Lehti, S; Lindén, T; Luukka, P; Mäenpää, T; Nysten, J; Tuominen, E; Tuominiemi, J; Ungaro, D; Wendland, L; Banzuzi, K; Korpela, A; Tuuva, T; Nedelec, P; Sillou, D; Besancon, M; Chipaux, R; Dejardin, M; Denegri, D; Descamps, J; Fabbro, B; Faure, J L; Ferri, F; Ganjour, S; Gentit, F X; Givernaud, A; Gras, P; Hamel de Monchenault, G; Jarry, P; Lemaire, M C; Locci, E; Malcles, J; Marionneau, M; Millischer, L; Rander, J; Rosowsky, A; Rousseau, D; Titov, M; Verrecchia, P; Baffioni, S; Bianchini, L; Bluj, M; Busson, P; Charlot, C; Dobrzynski, L; Granier de Cassagnac, R; Haguenauer, M; Miné, P; Paganini, P; Sirois, Y; Thiebaux, C; Zabi, A; Agram, J L; Besson, A; Bloch, D; Bodin, D; Brom, J M; Conte, E; Drouhin, F; Fontaine, J C; Gelé, D; Goerlach, U; Gross, L; Juillot, P; Le Bihan, A C; Patois, Y; Speck, J; Van Hove, P; Baty, C; Bedjidian, M; Blaha, J; Boudoul, G; Brun, H; Chanon, N; Chierici, R; Contardo, D; Depasse, P; Dupasquier, T; El Mamouni, H; Fassi, F; Fay, J; Gascon, S; Ille, B; Kurca, T; Le Grand, T; Lethuillier, M; Lumb, N; Mirabito, L; Perries, S; Vander Donckt, M; Verdier, P; Djaoshvili, N; Roinishvili, N; Roinishvili, V; Amaglobeli, N; Adolphi, R; Anagnostou, G; Brauer, R; Braunschweig, W; Edelhoff, M; Esser, H; Feld, L; Karpinski, W; Khomich, A; Klein, K; Mohr, N; Ostaptchouk, A; Pandoulas, D; Pierschel, G; Raupach, F; Schael, S; Schultz von Dratzig, A; Schwering, G; Sprenger, D; Thomas, M; Weber, M; Wittmer, B; Wlochal, M; Actis, O; Altenhöfer, G; Bender, W; Biallass, P; Erdmann, M; Fetchenhauer, G; Frangenheim, J; Hebbeker, T; Hilgers, G; Hinzmann, A; Hoepfner, K; Hof, C; Kirsch, M; Klimkovich, T; Kreuzer, P; Lanske, D; Merschmeyer, M; Meyer, A; Philipps, B; Pieta, H; Reithler, H; Schmitz, S A; Sonnenschein, L; Sowa, M; Steggemann, J; Szczesny, H; Teyssier, D; Zeidler, C; Bontenackels, M; Davids, M; Duda, M; Flügge, G; Geenen, H; Giffels, M; Haj Ahmad, W; Hermanns, T; Heydhausen, D; Kalinin, S; Kress, T; Linn, A; Nowack, A; Perchalla, L; Poettgens, M; Pooth, O; Sauerland, P; Stahl, A; Tornier, D; 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    2010-01-01

    The CMS detector is designed around a large 4 T superconducting solenoid, enclosed in a 12000-tonne steel return yoke. A detailed map of the magnetic field is required for the accurate simulation and reconstruction of physics events in the CMS detector, not only in the inner tracking region inside the solenoid but also in the large and complex structure of the steel yoke, which is instrumented with muon chambers. Using a large sample of cosmic muon events collected by CMS in 2008, the field in the steel of the barrel yoke has been determined with a precision of 3 to 8% depending on the location.

  19. Precise mapping of the magnetic field in the CMS barrel yoke using cosmic rays

    Energy Technology Data Exchange (ETDEWEB)

    Chatrchyan, S. [Yerevan Physics Institute (Aremenia); et al.,

    2010-03-01

    The CMS detector is designed around a large 4 T superconducting solenoid, enclosed in a 12000-tonne steel return yoke. A detailed map of the magnetic field is required for the accurate simulation and reconstruction of physics events in the CMS detector, not only in the inner tracking region inside the solenoid but also in the large and complex structure of the steel yoke, which is instrumented with muon chambers. Using a large sample of cosmic muon events collected by CMS in 2008, the field in the steel of the barrel yoke has been determined with a precision of 3 to 8% depending on the location.

  20. Precise Mapping of the Magnetic Field in the CMS Barrel Yoke using Cosmic Rays

    CERN Document Server

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Dagenhart, W; Demarteau, M; Derylo, G; Dykstra, D; Eartly, D P; Elias, J E; Elvira, V D; Evans, D; Feng, L; Fischler, M; Fisk, I; Foulkes, S; Freeman, J; Gartung, P; Gottschalk, E; Grassi, T; Green, D; Guo, Y; Gutsche, O; Hahn, A; Hanlon, J; Harris, R M; Holzman, B; Howell, J; Hufnagel, D; James, E; Jensen, H; Johnson, M; Jones, C D; Joshi, U; Juska, E; Kaiser, J; Klima, B; Kossiakov, S; Kousouris, K; Kwan, S; Lei, C M; Limon, P; Lopez Perez, J A; Los, S; Lueking, L; Lukhanin, G; Lusin, S; Lykken, J; Maeshima, K; Marraffino, J M; Mason, D; McBride, P; Miao, T; Mishra, K; Moccia, S; Mommsen, R; Mrenna, S; Muhammad, A S; Newman-Holmes, C; Noeding, C; O'Dell, V; Prokofyev, O; Rivera, R; Rivetta, C H; Ronzhin, A; Rossman, P; Ryu, S; Sekhri, V; Sexton-Kennedy, E; Sfiligoi, I; Sharma, S; Shaw, T M; Shpakov, D; Skup, E; Smith, R P; Soha, A; Spalding, W J; Spiegel, L; Suzuki, I; Tan, P; Tanenbaum, W; Tkaczyk, S; Trentadue, R; Uplegger, L; Vaandering, E W; Vidal, R; Whitmore, J; Wicklund, E; Wu, W; Yarba, J; Yumiceva, F; Yun, J C; Acosta, D; Avery, P; Barashko, V; Bourilkov, D; Chen, M; Di Giovanni, G P; Dobur, D; Drozdetskiy, A; Field, R D; Fu, Y; Furic, I K; Gartner, J; Holmes, D; Kim, B; Klimenko, S; Konigsberg, J; Korytov, A; Kotov, K; Kropivnitskaya, A; Kypreos, T; Madorsky, A; Matchev, K; Mitselmakher, G; Pakhotin, Y; Piedra Gomez, J; Prescott, C; Rapsevicius, V; Remington, R; Schmitt, M; Scurlock, B; Wang, D; Yelton, J; Ceron, C; Gaultney, V; Kramer, L; Lebolo, L M; Linn, S; Markowitz, P; Martinez, G; Rodriguez, J L; Adams, T; Askew, A; Baer, H; Bertoldi, M; Chen, J; Dharmaratna, W G D; Gleyzer, S V; Haas, J; Hagopian, S; Hagopian, V; Jenkins, M; Johnson, K F; Prettner, E; Prosper, H; Sekmen, S; Baarmand, M M; Guragain, S; Hohlmann, M; Kalakhety, H; Mermerkaya, H; Ralich, R; Vodopiyanov, I; Abelev, B; Adams, M R; Anghel, I M; Apanasevich, L; Bazterra, V E; Betts, R R; Callner, J; Castro, M A; Cavanaugh, R; Dragoiu, C; Garcia-Solis, E J; Gerber, C E; Hofman, D J; Khalatian, S; Mironov, C; Shabalina, E; Smoron, A; Varelas, N; Akgun, U; Albayrak, E A; Ayan, A S; Bilki, B; Briggs, R; Cankocak, K; Chung, K; Clarida, W; Debbins, P; Duru, F; Ingram, F D; Lae, C K; McCliment, E; Merlo, J P; Mestvirishvili, A; Miller, M J; Moeller, A; Nachtman, J; Newsom, C R; Norbeck, E; Olson, J; Onel, Y; Ozok, F; Parsons, J; Schmidt, I; Sen, S; Wetzel, J; Yetkin, T; Yi, K; Barnett, B A; Blumenfeld, B; Bonato, A; Chien, C Y; Fehling, D; Giurgiu, G; Gritsan, A V; Guo, Z J; Maksimovic, P; Rappoccio, S; Swartz, M; Tran, N V; Zhang, Y; Baringer, P; Bean, A; Grachov, O; Murray, M; Radicci, V; Sanders, S; Wood, J S; Zhukova, V; Bandurin, D; Bolton, T; Kaadze, K; Liu, A; Maravin, Y; Onoprienko, D; Svintradze, I; Wan, Z; Gronberg, J; Hollar, J; Lange, D; Wright, D; Baden, D; Bard, R; Boutemeur, M; Eno, S C; Ferencek, D; Hadley, N J; Kellogg, R G; Kirn, M; Kunori, S; Rossato, K; Rumerio, P; Santanastasio, F; Skuja, A; Temple, J; Tonjes, M B; Tonwar, S C; Toole, T; Twedt, E; Alver, B; Bauer, G; Bendavid, J; Busza, W; Butz, E; Cali, I A; Chan, M; D'Enterria, D; Everaerts, P; Gomez Ceballos, G; Hahn, K A; Harris, P; Jaditz, S; Kim, Y; Klute, M; Lee, Y J; Li, W; Loizides, C; Ma, T; Miller, M; Nahn, S; Paus, C; Roland, C; Roland, G; Rudolph, M; Stephans, G; Sumorok, K; Sung, K; Vaurynovich, S; Wenger, E A; Wyslouch, B; Xie, S; Yilmaz, Y; Yoon, A S; Bailleux, D; Cooper, S I; Cushman, P; Dahmes, B; De Benedetti, A; Dolgopolov, A; Dudero, P R; Egeland, R; Franzoni, G; Haupt, J; Inyakin, A; Klapoetke, K; Kubota, Y; Mans, J; Mirman, N; Petyt, D; Rekovic, V; Rusack, R; Schroeder, M; Singovsky, A; Zhang, J; Cremaldi, L M; Godang, R; Kroeger, R; Perera, L; Rahmat, R; Sanders, D A; Sonnek, P; Summers, D; Bloom, K; Bockelman, B; Bose, S; Butt, J; Claes, D R; Dominguez, A; Eads, M; Keller, J; Kelly, T; Kravchenko, I; Lazo-Flores, J; Lundstedt, C; Malbouisson, H; Malik, S; Snow, G R; Baur, U; Iashvili, I; Kharchilava, A; Kumar, A; Smith, K; Strang, M; Alverson, G; Barberis, E; Boeriu, O; Eulisse, G; 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Wigmans, R; Yazgan, E; Engh, D; Florez, C; Johns, W; Pathak, S; Sheldon, P; Andelin, D; Arenton, M W; Balazs, M; Boutle, S; Buehler, M; Conetti, S; Cox, B; Hirosky, R; Ledovskoy, A; Neu, C; Phillips II, D; Ronquest, M; Yohay, R; Gollapinni, S; Gunthoti, K; Harr, R; Karchin, P E; Mattson, M; Sakharov, A; Anderson, M; Bachtis, M; Bellinger, J N; Carlsmith, D; Crotty, I; Dasu, S; Dutta, S; Efron, J; Feyzi, F; Flood, K; Gray, L; Grogg, K S; Grothe, M; Hall-Wilton, R; Jaworski, M; Klabbers, P; Klukas, J; Lanaro, A; Lazaridis, C; Leonard, J; Loveless, R; Magrans de Abril, M; Mohapatra, A; Ott, G; Polese, G; Reeder, D; Savin, A; Smith, W H; Sourkov, A; Swanson, J; Weinberg, M; Wenman, D; Wensveen, M; White, A

    2010-01-01

    The CMS detector is designed around a large 4 T superconducting solenoid, enclosed in a 12000-tonne steel return yoke. A detailed map of the magnetic field is required for the accurate simulation and reconstruction of physics events in the CMS detector, not only in the inner tracking region inside the solenoid but also in the large and complex structure of the steel yoke, which is instrumented with muon chambers. Using a large sample of cosmic muon events collected by CMS in 2008, the field in the steel of the barrel yoke has been determined with a precision of 3 to 8% depending on the location.

  1. The Cosmic Microwave Background Radiation Power Spectrum as a Random Bit Generator for Symmetric and Asymmetric-Key Cryptography

    CERN Document Server

    Lee, Jeffrey S

    2016-01-01

    In this note, the Cosmic Microwave Background (CMB) Radiation is shown to be capable of functioning as a Random Bit Generator, and constitutes an effectively infinite supply of truly random one-time pad values of arbitrary length. It is further argued that the CMB power spectrum potentially conforms to the FIPS 140-2 standard. Additionally, its applicability to the generation of a (n x n) random key matrix for a Vernam cipher is established.

  2. Effects of External Radiation Fields on Line Emission—Application to Star-forming Regions

    Science.gov (United States)

    Chatzikos, Marios; Ferland, G. J.; Williams, R. J. R.; Porter, Ryan; van Hoof, P. A. M.

    2013-12-01

    A variety of astronomical environments contain clouds irradiated by a combination of isotropic and beamed radiation fields. For example, molecular clouds may be irradiated by the isotropic cosmic microwave background, as well as by a nearby active galactic nucleus. These radiation fields excite atoms and molecules and produce emission in different ways. We revisit the escape probability theorem and derive a novel expression that accounts for the presence of external radiation fields. We show that when the field is isotropic the escape probability is reduced relative to that in the absence of external radiation. This is in agreement with previous results obtained under ad hoc assumptions or with the two-level system, but can be applied to complex many-level models of atoms or molecules. This treatment is in the development version of the spectral synthesis code CLOUDY. We examine the spectrum of a Spitzer cloud embedded in the local interstellar radiation field and show that about 60% of its emission lines are sensitive to background subtraction. We argue that this geometric approach could provide an additional tool toward understanding the complex radiation fields of starburst galaxies.

  3. Propagation of high-energy cosmic rays in extragalactic turbulent magnetic fields: resulting energy spectrum and composition

    CERN Document Server

    Globus, N; Parizot, E

    2007-01-01

    We extend previous studies of mixed-composition extragalactic cosmic-ray source models, by investigating the influence of a non-negligible extragalactic magnetic field on the propagated cosmic-ray spectrum and composition. We study the transport of charged particles in turbulent fields and the transition from a ballistic to a diffusive propagation regime. We introduce a method allowing a fast integration of the particle trajectories, which allows us to calculate extragalactic cosmic-ray spectra in the general case, without using either the diffusive or the rectilinear approximation. We find that the main features of the mixed-composition models -- regarding the interpretation of the ankle and the non-monotonous evolution of the average cosmic-ray mass -- remain essentially unchanged as long as the magnetic field intensity does not exceed a few nG.

  4. Plasma wake field XUV radiation source

    Energy Technology Data Exchange (ETDEWEB)

    Prono, Daniel S. (Los Alamos, NM); Jones, Michael E. (Los Alamos, NM)

    1997-01-01

    A XUV radiation source uses an interaction of electron beam pulses with a gas to create a plasma radiator. A flowing gas system (10) defines a circulation loop (12) with a device (14), such as a high pressure pump or the like, for circulating the gas. A nozzle or jet (16) produces a sonic atmospheric pressure flow and increases the density of the gas for interacting with an electron beam. An electron beam is formed by a conventional radio frequency (rf) accelerator (26) and electron pulses are conventionally formed by a beam buncher (28). The rf energy is thus converted to electron beam energy, the beam energy is used to create and then thermalize an atmospheric density flowing gas to a fully ionized plasma by interaction of beam pulses with the plasma wake field, and the energetic plasma then loses energy by line radiation at XUV wavelengths Collection and focusing optics (18) are used to collect XUV radiation emitted as line radiation when the high energy density plasma loses energy that was transferred from the electron beam pulses to the plasma.

  5. The Stellar Extreme-Ultraviolet Radiation Field

    Science.gov (United States)

    Vallerga, John

    1998-04-01

    The local extreme ultraviolet (EUV) radiation field from stellar sources has been determined by combining the EUV spectra of 54 stars, taken with the spectrometers aboard the Extreme Ultraviolet Explorer satellite. The resultant spectrum over the range 70-730 Å is estimated to be 95% complete above 400 Å and 90% complete above 200 Å. The flux contributed by two B stars and three hot white dwarfs dominate the spectrum except at the shortest wavelengths, where an assortment of EUV source types contribute. The high electron densities measured toward nearby stars can be accounted for by photoionization from this radiation field, but the spectrum is too soft to explain the overionization of helium with respect to hydrogen recently measure in the Local Cloud.

  6. A new probe of the magnetic field power spectrum in cosmic web filaments

    Science.gov (United States)

    Hales, Christopher A.; Greiner, Maksim; Ensslin, Torsten A.

    2015-08-01

    Establishing the properties of magnetic fields on scales larger than galaxy clusters is critical for resolving the unknown origin and evolution of galactic and cluster magnetism. More generally, observations of magnetic fields on cosmic scales are needed for assessing the impacts of magnetism on cosmology, particle physics, and structure formation over the full history of the Universe. However, firm observational evidence for magnetic fields in large scale structure remains elusive. In an effort to address this problem, we have developed a novel statistical method to infer the magnetic field power spectrum in cosmic web filaments using observation of the two-point correlation of Faraday rotation measures from a dense grid of extragalactic radio sources. Here we describe our approach, which embeds and extends the pioneering work of Kolatt (1998) within the context of Information Field Theory (a statistical theory for Bayesian inference on spatially distributed signals; Enfllin et al., 2009). We describe prospects for observation, for example with forthcoming data from the ultra-deep JVLA CHILES Con Pol survey and future surveys with the SKA.

  7. Weak cosmic censorship, dyonic Kerr-Newman black holes and Dirac fields

    CERN Document Server

    Toth, Gabor Zsolt

    2015-01-01

    It was investigated recently, with the aim of testing the weak cosmic censorship conjecture, whether an extremal Kerr black hole can be converted into a naked singularity by interaction with a massless classical Dirac test field, and it was found that this is possible. We generalize this result to electrically and magnetically charged rotating extremal black holes (i.e. extremal dyonic Kerr-Newman black holes) and massive Dirac test fields, allowing magnetically or electrically uncharged or nonrotating black holes and the massless Dirac field as special cases. We show that the possibility of the conversion is a direct consequence of the fact that the Einstein-Hilbert energy-momentum tensor of the classical Dirac field does not satisfy the null energy condition, and is therefore not in contradiction with the weak cosmic censorship conjecture. We give a derivation of the absence of superradiance of the Dirac field without making use of the complete separability of the Dirac equation in dyonic Kerr-Newman backgr...

  8. Future Observations of Cosmic Magnetic Fields with LOFAR, SKA and Its Precursors

    Science.gov (United States)

    Beck, Rainer

    Polarization observations with the forthcoming large radio telescopes will open a new era in the observation of magnetic fields and should help to understand their origin. Low-frequency radio synchrotron emission from the Milky Way, galaxies and galaxy clusters, observed with the new Low Frequency Array (LOFAR) and the planned Square Kilometre Array (SKA), traces low-energy cosmic ray electrons and allows us to map the structure of weak magnetic fields in the outer regions and halos of galaxies, in halos and relics of clusters and in the Milky Way. Polarization at higher frequencies (1-10 GHz), to be observed with the SKA and its precursors Australia SKA Pathfinder (ASKAP) and the South African MeerKAT telescopes, will trace magnetic fields in the disks and central regions of galaxies and in cluster relics in unprecedented detail. All-sky surveys of Faraday rotation measures towards a dense grid of polarized background sources with ASKAP (project POSSUM) and the SKA are dedicated to measure magnetic fields in intervening galaxies, clusters and intergalactic filaments, and will be used to model the overall structure and strength of magnetic fields in the Milky Way. Cosmic magnetism is "key science" for LOFAR, ASKAP and the SKA.

  9. Response of TL dosemeters to cosmic radiation on board passenger aircraft

    CERN Document Server

    Bilski, P; Marczewska, B; Olko, P

    2002-01-01

    Measurements were performed with various LiF based TLDs on board seven Polish aircraft, flying long-distance or middle-distance routes. All of the /sup 7/LiF detectors used (various types of /sup 7 /LiF:Mg, Ti and /sup 7/LiF:Mg, Cu, P detectors), which measure the non-neutron component of the radiation field, produced consistent results. It was found that the characteristics of the TLD response (ratio of different detector responses, glow curve shapes) after doses of radiation at flying altitudes differ from those obtained after exposure at the CERN facility (CERF), suggesting a lower contribution of densely ionising radiation. The neutron induced TL signal was also more affected by the thickness of the holder, suggesting the presence of a softer neutron energy spectrum at flight altitudes. Further in-flight and CERF exposures of detectors are planned to resolve these issues. (5 refs).

  10. Radiating black holes in Einstein-Maxwell-dilaton theory and cosmic censorship violation

    Science.gov (United States)

    Aniceto, Pedro; Pani, Paolo; Rocha, Jorge V.

    2016-05-01

    We construct exact, time-dependent, black hole solutions of Einstein-Maxwell-dilaton theory with arbitrary dilaton coupling, a. For a = 1 this theory arises as the four-dimensional low-energy effective description of heterotic string theory. These solutions represent electrically charged, spherically symmetric black holes emitting or absorbing charged null fluids and generalize the Vaidya and Bonnor-Vaidya solutions of general relativity and of Einstein-Maxwell theory, respectively. The a = 1 case stands out as special, in the sense that it is the only choice of the coupling that allows for a time-dependent dilaton field in this class of solutions. As a by-product, when a = 1 we show that an electrically charged black hole in this theory can be overcharged by bombarding it with a stream of electrically charged null fluid, resulting in the formation of a naked singularity. This provides an example of cosmic censorship violation in an exact dynamical solution to low-energy effective string theory and in a case in which the total stress-energy tensor satisfies all energy conditions. When a ≠ 1, our solutions necessarily have a time-independent scalar field and consequently cannot be overcharged.

  11. Long-term modulation of galactic cosmic radiation and its model for space exploration

    Science.gov (United States)

    Badhwar, G. D.; O'Neill, P. M.

    1994-10-01

    As the human exploration of space has received new attention in the United States, studies find that exposure to space radiation could adversely impact the mission design. Galactic Cosmic Radiation (GCR), with its very wide range of charges and energies, is particularly important for a mission to Mars, because it imposes a stiff mass penalty for spacecraft shielding. Dose equivalent versus shielding thickness calculations, show a rapid initial drop on exposure with thickness, but an asymptotic behavior at a higher shielding thickness. Uncertainties in the radiobiology are largely unknown. For a fixed radiation risk, this leads to large uncertainties in shielding thickness for small uncertainties in estimated dose. In this paper we investigate the application of steady-state, spherically-symmetric diffusion-convection theory of solar modulation to individual measurements of differential energy spectra from 1954 to 1989 in order to estimate the diffusion coefficient, kappa(r,t), as a function of time. We have correlated the diffusion coefficient to the Climax neutron monitor rates and show that, if the diffusion coefficient can be separated into independent functions of space and time: kappa(r,t)=K(t) k0 beta Pk1 (r), where beta is the particle velocity and P the rigidity, then (i) The time dependent quantity 1/K(t), which is proportional to the deceleration potential, phi(r,t), is linearly related to the Climax neutron monitor counting rate. (ii) The coefficients obtained from hydrogen or helium intensity measurements are the same. (iii) There are different correlation functions for odd and even solar cycles. (iv) The correlation function for the Climax neutron monitor counting rate for given time, t, can be used to estimate mean deceleration parameter phi(t) to within +/- 15% with 90% confidence. We have shown that k(r,t) determined from hydrogen and/or helium data, can be used to fit the oxygen and iron differential energy spectra with a root mean square error of

  12. Slow decay of cosmic magnetic fields superadiabatically in curvature-torsion scales

    CERN Document Server

    de Andrade, L C Garcia

    2014-01-01

    Recently Barrow, and Tsagas [Phys Rev D 77: 107302, (2008)] have shown that slow decay of cosmological magnetic slowly decay in FRW universes on curvature scales as $B\\sim{a^{-1}}$ in the context of general relativity (GR). This helps possible amplification of cosmic magnetic fields. In this paper starting from dynamo equations in spacetimes with torsion we obtain also slow decay of magnetic fields naturally on curvature-torsion scales of Riemann-Cartan spacetime on a de Sitter universe. In this case the constant of proportionality between the magnetic field and the curvature scale is the torsion in the present universe. Thus the B-field becomes $B\\sim{\\frac{{\\eta}}{H_{0}}Ta^{-1}}$ where T is torsion vector modulus, $H_{0}$ is the Hubble constant and $\\eta$ is the diffusive scale.

  13. Turbulent magnetic field amplification driven by cosmic-ray pressure gradients

    CERN Document Server

    Drury, Luke O'C

    2012-01-01

    Observations of non-thermal emission from several supernova remnants suggest that magnetic fields close to the blastwave are much stronger than would be naively expected from simple shock compression of the field permeating the interstellar medium (ISM). We present a simple model which is capable of achieving sufficient magnetic field amplification to explain the observations. We propose that the cosmic-ray pressure gradient acting on the inhomogeneous ISM upstream of the supernova blastwave induces strong turbulence upstream of the supernova blastwave. The turbulence is generated through the differential acceleration of the upstream ISM which occurs as a result of density inhomogeneities in the ISM. This turbulence then amplifies the pre-existing magnetic field. Numerical simulations are presented which demonstrate that amplification factors of 20 or more are easily achievable by this mechanism when reasonable parameters for the ISM and supernova blastwave are assumed. The length scale over which this amplif...

  14. Dynamical effects of self-generated magnetic fields in cosmic ray modified shocks

    CERN Document Server

    Caprioli, Damiano; Amato, Elena; Vietri, Mario

    2008-01-01

    Recent observations of greatly amplified magnetic fields ($\\delta B/B\\sim 100$) around supernova shocks are consistent with the predictions of the non-linear theory of particle acceleration (NLT), if the field is generated upstream of the shock by cosmic ray induced streaming instability. The high acceleration efficiencies and large shock modifications predicted by NLT need however to be mitigated to confront observations, and this is usually assumed to be accomplished by some form of turbulent heating. We show here that magnetic fields with the strength inferred from observations have an important dynamical role on the shock, and imply a shock modification substantially reduced with respect to the naive unmagnetized case. The effect appears as soon as the pressure in the turbulent magnetic field becomes comparable with the pressure of the thermal gas. The relative importance of this unavoidable effect and of the poorly known turbulent heating is assessed. More specifically we conclude that even in the cases ...

  15. Radiation damage of polymers in ultrasonic fields

    Energy Technology Data Exchange (ETDEWEB)

    Anbalagan, Poornnima

    2008-07-01

    Radiation damage has always been a topic of great interest in various fields of sciences. In this work, an attempt is made to probe into the effect of subthreshold ultrasonic waves on the radiation damage created by irradiation of deuterons in polymer samples wherein the polymer samples act as model systems. Two equal volumes of radiation damage were produced in a single polymer sample wherein a standing wave of ultrasound was introduced into one. Three polymers namely, Polycarbonate, Polymethylmethacrylate and Polyvinyl chloride were used in this work. Four independent techniques were used to analyze the irradiated samples and visualize the radiation damage. Interferometric measurements give a measure of the refractive index modulation in the irradiated sample. Polymers, being transparent, do not absorb in the visible region of the electromagnetic spectrum. UV-Vis absorption spectroscopy shows absorption peaks in the visible region in irradiated polymer samples. Ion irradiation causes coloration of polymers. The light microscope is used to measure the absorption of white light by the irradiated polymers. Positron annihilation spectroscopy is used to obtain a measure of the open volume created by irradiation in polymers. A comparison between the irradiated region and the region exposed to ultrasonic waves simultaneously with irradiation in a polymer sample shows the polymer specific influence of the ultrasonic standing wave. (orig.)

  16. Momentum of the Pure Radiation Field

    Directory of Open Access Journals (Sweden)

    Lehnert B.

    2007-01-01

    Full Text Available The local momentum equation of the pure radiation field is considered in terms of an earlier elaborated and revised electromagnetic theory. In this equation the contribution from the volume force is found to vanish in rectangular geometry, and to become nonzero but negligible in cylindrical geometry. Consequently the radiated momentum is due to the Poynting vector only, as in conventional electrodynamics. It results in physically relevant properties of a photon model having an angular momentum (spin. The Poynting vector concept is further compared to the quantized momentum concept for a free particle, as represented by a spatial gradient operator acting on the wave function. However, this latter otherwise successful concept leads to difficulties in the physical interpretation of known and expected photon properties such as the spin, the negligible loss of transverse momentum across a bounding surface, and the Lorentz invariance.

  17. Cosmic magnetization: from spontaneously emitted aperiodic turbulent to ordered equipartition fields.

    Science.gov (United States)

    Schlickeiser, R

    2012-12-28

    It is shown that an unmagnetized nonrelativistic thermal electron-proton plasma spontaneously emits aperiodic turbulent magnetic field fluctuations of strength |δB|=3.5β(e)g(1/3)W(e)(1/2)  G, where β(e) is the normalized thermal electron temperature, W(e) the thermal plasma energy density, and g the plasma parameter. For the unmagnetized intergalactic medium, immediately after the reionization onset, the field strengths from this mechanism are about 2×10(-16)  G in cosmic voids and 2×10(-10)  G in protogalaxies, both too weak to affect the dynamics of the plasma. Accounting for simultaneous viscous damping reduces these estimates to 2×10(-21)  G in cosmic voids and 2×10(-12)  G in protogalaxies. The shear and/or compression of the intergalactic and protogalactic medium exerted by the first supernova explosions locally amplify these seed fields and make them anisotropic, until the magnetic restoring forces affect the gas dynamics at ordered plasma betas near unity.

  18. Cosmic Ray Acceleration by E-Parallel Reconnection of Force-Free Fields

    CERN Document Server

    Colgate, S A; Colgate, Stirling A.; Li, Hui

    2004-01-01

    We propose that nearly every accelerated CR was part of the parallel current that maintains all force-free (f-f) magnetic fields. Charged particles are accelerated by the E-parallel (to the magnetic filed B) produced by reconnection. The inferred total energy in extra-galactic cosmic rays is 10^(60) ergs per galaxy spacing volume, provided that acceleration mechanisms assumed do not preferentially only accelerate ultra high energy cosmic rays (UHECRs). This total energy is about 10^5 times the parent galactic CR or magnetic energy. The formation energy of supermassive black holes (SMBHs) at galaxy centers, 10^(62) ergs, becomes the only feasible source. An efficient dynamo process converts gravitational free energy into magnetic energy in an accretion disk around a SMBH. Aided by Keplerian winding, this dynamo converts a poloidal seed field into f-f fields, which are transported into the general inter-galactic medium (IGM). This magnetic energy is also efficiently converted into particle energies, as evidence...

  19. Latitudinal Dependence of Cosmic Rays Modulation at 1 AU and Interplanetary Magnetic Field Polar Correction

    Directory of Open Access Journals (Sweden)

    P. Bobik

    2013-01-01

    Full Text Available The cosmic rays differential intensity inside the heliosphere, for energy below 30 GeV/nuc, depends on solar activity and interplanetary magnetic field polarity. This variation, termed solar modulation, is described using a 2D (radius and colatitude Monte Carlo approach for solving the Parker transport equation that includes diffusion, convection, magnetic drift, and adiabatic energy loss. Since the whole transport is strongly related to the interplanetary magnetic field (IMF structure, a better understanding of his description is needed in order to reproduce the cosmic rays intensity at the Earth, as well as outside the ecliptic plane. In this work an interplanetary magnetic field model including the standard description on ecliptic region and a polar correction is presented. This treatment of the IMF, implemented in the HelMod Monte Carlo code (version 2.0, was used to determine the effects on the differential intensity of Proton at 1 AU and allowed one to investigate how latitudinal gradients of proton intensities, observed in the inner heliosphere with the Ulysses spacecraft during 1995, can be affected by the modification of the IMF in the polar regions.

  20. Probing Atmospheric Electric Fields through Radio Emission from Cosmic-Ray-Induced Air Showers

    Science.gov (United States)

    Scholten, Olaf; Trinh, Gia; Buitink, Stijn; Corstanje, Arthur; Ebert, Ute; Enriquez, Emilio; Falcke, Heino; Hoerandel, Joerg; Nelles, Anna; Schellart, Pim; Rachen, Joerg; Rutjes, Casper; ter Veen, Sander; Rossetto, Laura; Thoudam, Satyendra

    2016-04-01

    Energetic cosmic rays impinging on the atmosphere create a particle avalanche called an extensive air shower. In the leading plasma of this shower electric currents are induced that generate coherent radio wave emission that has been detected with LOFAR, a large and dense array of simple radio antennas primarily developed for radio-astronomy observations. Our measurements are performed in the 30-80 MHz frequency band. For fair weather conditions the observations are in excellent agreement with model calculations. However, for air showers measured under thunderstorm conditions we observe large differences in the intensity and polarization patterns from the predictions of fair weather models. We will show that the linear as well as the circular polarization of the radio waves carry clear information on the magnitude and orientation of the electric fields at different heights in the thunderstorm clouds. We will show that from the measured data at LOFAR the thunderstorm electric fields can be reconstructed. We thus have established the measurement of radio emission from extensive air showers induced by cosmic rays as a new tool to probe the atmospheric electric fields present in thunderclouds in a non-intrusive way. In part this presentation is based on the work: P. Schellart et al., Phys. Rev. Lett. 114, 165001 (2015).

  1. Virtual radiation fields for ALARA determination

    Energy Technology Data Exchange (ETDEWEB)

    Knight, T.W.

    1995-12-31

    As computing power has increased, so too has the ability to model and simulate complex systems and processes. In addition, virtual reality technology has made it possible to visualize and understand many complex scientific and engineering problems. For this reason, a virtual dosimetry program called Virtual Radiation Fields (VRF) is developed to model radiation dose rate and cumulative dose to a receptor operating in a virtual radiation environment. With the design and testing of many facilities and products taking place in the virtual world, this program facilitates the concurrent consideration of radiological concerns during the design process. Three-dimensional (3D) graphical presentation of the radiation environment is made possible through the use of IGRIP, a graphical modeling program developed by Deneb Robotics, Inc. The VRF simulation program was designed to model and display a virtual dosimeter. As a demonstration of the program`s capability, the Hanford tank, C-106, was modeled to predict radiation doses to robotic equipment used to remove radioactive waste from the tank. To validate VRF dose predictions, comparison was made with reported values for tank C-106, which showed agreement to within 0.5%. Graphical information is presented regarding the 3D dose rate variation inside the tank. Cumulative dose predictions were made for the cleanup operations of tank C-106. A four-dimensional dose rate map generated by VRF was used to model the dose rate not only in 3D space but also as a function of the amount of waste remaining in the tank. This allowed VRF to predict dose rate at any stage in the waste removal process for an accurate simulation of the radiological conditions throughout the tank cleanup procedure.

  2. LiteBIRD: a small satellite for the study of B-mode polarization and inflation from cosmic background radiation detection

    Science.gov (United States)

    Hazumi, M.; Borrill, J.; Chinone, Y.; Dobbs, M. A.; Fuke, H.; Ghribi, A.; Hasegawa, M.; Hattori, K.; Hattori, M.; Holzapfel, W. L.; Inoue, Y.; Ishidoshiro, K.; Ishino, H.; Karatsu, K.; Katayama, N.; Kawano, I.; Kibayashi, A.; Kibe, Y.; Kimura, N.; Koga, K.; Komatsu, E.; Lee, A. T.; Matsuhara, H.; Matsumura, T.; Mima, S.; Mitsuda, K.; Morii, H.; Murayama, S.; Nagai, M.; Nagata, R.; Nakamura, S.; Natsume, K.; Nishino, H.; Noda, A.; Noguchi, T.; Ohta, I.; Otani, C.; Richards, P. L.; Sakai, S.; Sato, N.; Sato, Y.; Sekimoto, Y.; Shimizu, A.; Shinozaki, K.; Sugita, H.; Suzuki, A.; Suzuki, T.; Tajima, O.; Takada, S.; Takagi, Y.; Takei, Y.; Tomaru, T.; Uzawa, Y.; Watanabe, H.; Yamasaki, N.; Yoshida, M.; Yoshida, T.; Yotsumoto, K.

    2012-09-01

    LiteBIRD [Lite (Light) satellite for the studies of B-mode polarization and Inflation from cosmic background Radiation Detection] is a small satellite to map the polarization of the cosmic microwave background (CMB) radiation over the full sky at large angular scales with unprecedented precision. Cosmological inflation, which is the leading hypothesis to resolve the problems in the Big Bang theory, predicts that primordial gravitational waves were created during the inflationary era. Measurements of polarization of the CMB radiation are known as the best probe to detect the primordial gravitational waves. The LiteBIRD working group is authorized by the Japanese Steering Committee for Space Science (SCSS) and is supported by JAXA. It has more than 50 members from Japan, USA and Canada. The scientific objective of LiteBIRD is to test all the representative inflation models that satisfy single-field slow-roll conditions and lie in the large-field regime. To this end, the requirement on the precision of the tensor-to-scalar ratio, r, at LiteBIRD is equal to or less than 0.001. Our baseline design adopts an array of multi-chroic superconducting polarimeters that are read out with high multiplexing factors in the frequency domain for a compact focal plane. The required sensitivity of 1.8μKarcmin is achieved with 2000 TES bolometers at 100mK. The cryogenic system is based on the Stirling/JT technology developed for SPICA, and the continuous ADR system shares the design with future X-ray satellites.

  3. Theoretical Evaluation of the Radiation Hazards from Cosmic Rays Within Space Vehicles

    Science.gov (United States)

    Katz, Robert

    1998-01-01

    We may summarize our efforts as follows: a. Improvement of our calculations of the radial dose distribution from delta rays ejected in the passage of heavy ions through matter through the application of new data to a previous calculation by Kobetich and Katz (1968). Supplementing this calculation, we have found the radial distribution of electron energy spectra and the radial distribution of microdosimetric quantities (Cucinotta et al, 1996, 1997). b. Extension of the Katz model of cellular survival to bacteria, to lethal mutations in C. Elegans in vivo, to mutation induction in vitro, to thindown in radiobiology (observed experimentally at GSI, Darmstadt, and there called "Darmstadt hooks", predicted by Katz theory years before GSI was constructed). c. Coupling the Katz theory of RBE to the NASA theory of the diffusion of heavy ion beams in matter to yield predictions of the effects for monoenergetic heavy ion beams as well as range modulated beams used for cancer therapy. Here we have directed attention to the role of "ion-kill" (the effects produced by heavy ions passing through the nucleus of a cell), responsible for increased RBE, decreased OER, and reduced repair. We predict that the use of beams of heavy ions in cancer therapy will create late effect problems for fractionated therapy. We highlight also the damage by "ion-kill", from single heavy ions in the cosmic rays, to the central nervous system in space flight. d. The coupling of Katz theory and the NASA theory of heavy ion diffusion and penetration through matter, and knowledge of the space radiation environment, has been applied to design of shielding, to the cell damage in space flight.

  4. On the angular distribution of cosmic rays from an individual source in a turbulent magnetic field

    CERN Document Server

    Harari, Diego; Roulet, Esteban

    2015-01-01

    We obtain the angular distribution of the cosmic rays reaching an observer from an individual source and after propagation through a turbulent magnetic field, for different ratios between the source distance and the diffusion length. We study both the high-energy quasi-rectilinear regime as well as the transition towards the diffusive regime at lower energies where the deflections become large. We consider the impact of energy losses, showing that they tend to enhance the anisotropy of the source at a given energy. We also discuss lensing effects, in particular those that could result from the regular galactic magnetic field component, and show that the effect of the turbulent extragalactic magnetic fields can smooth out the divergent magnification peaks that would result for point-like sources in the limit of no turbulent deflections.

  5. Gravitational Waves from Abelian Gauge Fields and Cosmic Strings at Preheating

    CERN Document Server

    Dufaux, Jean-Francois; Garcia-Bellido, Juan

    2010-01-01

    Primordial gravitational waves provide a very important stochastic background that could be detected soon with interferometric gravitational wave antennas or indirectly via the induced patterns in the polarization anisotropies of the cosmic microwave background. The detection of these waves will open a new window into the early Universe, and therefore it is important to characterize in detail all possible sources of primordial gravitational waves. In this paper we develop theoretical and numerical methods to study the production of gravitational waves from out-of-equilibrium gauge fields at preheating. We then consider models of preheating after hybrid inflation, where the symmetry breaking field is charged under a local U(1) symmetry. We analyze in detail the dynamics of the system in both momentum and configuration space, and show that gauge fields leave specific imprints in the resulting gravitational wave spectra, mainly through the appearence of new peaks at characteristic frequencies that are related to...

  6. Simulation of Cosmic Microwave Background Polarization Fields for AMiBA Experiment

    CERN Document Server

    Park, C G; Park, Chan-Gyung; Park, Changbom

    2002-01-01

    We have made a topological study of cosmic microwave background (CMB) polarization maps by simulating the AMiBA experiment results. A $\\Lambda$CDM CMB sky is adopted to make mock interferometric observations designed for the AMiBA experiment. CMB polarization fields are reconstructed from the AMiBA mock visibility data using the maximum entropy method. We have also considered effects of Galactic foregrounds on the CMB polarization fields. The genus statistic is calculated from the simulated $Q$ and $U$ polarization maps, where $Q$ and $U$ are Stokes parameters. Our study shows that the Galactic foreground emission, even at low Galactic latitude, is expected to have small effects on the CMB polarization field. Increasing survey area and integration time is essential to detect non-Gaussian signals of cosmological origin through genus measurement.

  7. Probing the Cosmic X-Ray and MeV Gamma-Ray Background Radiation through the Anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Yoshiyuki [Stanford Univ., CA (United States). Kavli Inst. for Particle Astrophysics and Cosmology; SLAC National Accelerator Lab., Menlo Park, CA (United States); Murase, Kohta [Inst. for Advanced Study, Princeton, NJ (United States). School of Natural Sciences; Madejski, Grzegorz M. [Stanford Univ., CA (United States). Kavli Inst. for Particle Astrophysics and Cosmology; SLAC National Accelerator Lab., Menlo Park, CA (United States); Uchiyama, Yasunobu [Stanford Univ., CA (United States). Kavli Inst. for Particle Astrophysics and Cosmology; SLAC National Accelerator Lab., Menlo Park, CA (United States); Rikkyo Univ., Tokyo (Japan). Dept. of Physics

    2013-09-24

    While the cosmic soft X-ray background is very likely to originate from individual Seyfert galaxies, the origin of the cosmic hard X-ray and MeV gamma-ray background is not fully understood. It is expected that Seyferts including Compton thick population may explain the cosmic hard X-ray background. At MeV energy range, Seyferts having non-thermal electrons in coronae above accretion disks or MeV blazars may explain the background radiation. We propose that future measurements of the angular power spectra of anisotropy of the cosmic X-ray and MeV gamma-ray backgrounds will be key to deciphering these backgrounds and the evolution of active galactic nuclei (AGNs). As AGNs trace the cosmic large-scale structure, spatial clustering of AGNs exists. We show that e-ROSITA will clearly detect the correlation signal of unresolved Seyferts at 0.5-2 keV and 2-10 keV bands and will be able to measure the bias parameter of AGNs at both bands. Once the future hard X-ray all sky satellites achieve the sensitivity better than 10-12 erg/cm2/s-1 at 10-30 keV or 30-50 keV - although this is beyond the sensitivities of current hard X-ray all sky monitors - angular power spectra will allow us to independently investigate the fraction of Compton-thick AGNs in all Seyferts. We also find that the expected angular power spectra of Seyferts and blazars in the MeV range are different by about an order of magnitude, where the Poisson term, so-called shot noise, is dominant. Current and future MeV instruments will clearly disentangle the origin of the MeV gamma-ray background through the angular power spectrum.

  8. Probing the cosmic x-ray and MeV gamma ray background radiation through the anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Yoshiyuki [Stanford Univ., CA (United States); Murase, Kohta [Inst. for Advanced Study, Princeton, NJ (United States); Madejski, Grzegorz M. [Stanford Univ., CA (United States); Uchiyama, Yasunobu [Stanford Univ., CA (United States); Rikkyo Univ., Tokyo (Japan)

    2013-09-24

    While the cosmic soft X-ray background is very likely to originate from individual Seyfert galaxies, the origin of the cosmic hard X-ray and MeV gamma-ray background is not fully understood. It is expected that Seyferts including Compton thick population may explain the cosmic hard X-ray background. At MeV energy range, Seyferts having non-thermal electrons in coronae above accretion disks or MeV blazars may explain the background radiation. We propose that future measurements of the angular power spectra of anisotropy of the cosmic X-ray and MeV gamma-ray backgrounds will be key to deciphering these backgrounds and the evolution of active galactic nuclei (AGNs). As AGNs trace the cosmic large-scale structure, spatial clustering of AGNs exists. We show that e-ROSITA will clearly detect the correlation signal of unresolved Seyferts at 0.5-2 keV and 2-10 keV bands and will be able to measure the bias parameter of AGNs at both bands. Once future hard X-ray all sky satellites achieve a sensitivity better than 10–12 erg cm–2 s–1 at 10-30 keV or 30-50 keV—although this is beyond the sensitivities of current hard X-ray all sky monitors—angular power spectra will allow us to independently investigate the fraction of Compton-thick AGNs in all Seyferts. We also find that the expected angular power spectra of Seyferts and blazars in the MeV range are different by about an order of magnitude, where the Poisson term, so-called shot noise, is dominant. Current and future MeV instruments will clearly disentangle the origin of the MeV gamma-ray background through the angular power spectrum.

  9. Occupational cosmic radiation exposure in Portuguese airline pilots: study of a possible correlation with oxidative biological markers.

    Science.gov (United States)

    Silva, Rodrigo; Folgosa, Filipe; Soares, Paulo; Pereira, Alice S; Garcia, Raquel; Gestal-Otero, Juan Jesus; Tavares, Pedro; Gomes da Silva, Marco D R

    2013-05-01

    Several studies have sought to understand the health effects of occupational exposure to cosmic radiation. However, only few biologic markers or associations with disease outcomes have so far been identified. In the present study, 22 long- and 26 medium-haul male Portuguese airline pilots and 36 factory workers who did not fly regularly were investigated. The two groups were comparable in age and diet, were non-smokers, never treated with ionizing radiation and other factors. Cosmic radiation exposure in pilots was quantified based on direct monitoring of 51 flights within Europe, and from Europe to North and South America, and to Africa. Indirect dose estimates in pilots were performed based on the SIEVERT (Système informatisé d'évaluation par vol de l'exposition au rayonnement cosmique dans les transports aériens) software for 6,039 medium- and 1,366 long-haul flights. Medium-haul pilots had a higher cosmic radiation dose rate than long-haul pilots, that is, 3.3 ± 0.2 μSv/h and 2.7 ± 0.3 μSv/h, respectively. Biological tests for oxidative stress on blood and urine, as appropriate, at two time periods separated by 1 year, included measurements of antioxidant capacity, total protein, ferritin, hemoglobin, creatinine and 8-hydroxy-2-deoxyguanosine (8OHdG). Principal components analysis was used to discriminate between the exposed and unexposed groups based on all the biological tests. According to this analysis, creatinine and 8OHdG levels were different for the pilots and the unexposed group, but no distinctions could be made among the medium- and the long-haul pilots. While hemoglobin levels seem to be comparable between the studied groups, they were directly correlated with ferritin values, which were lower for the airline pilots.

  10. Effects of External Radiation Fields on Line Emission - Application to Star-forming Regions

    CERN Document Server

    Chatzikos, Marios; Williams, Robin; van Hoof, Peter; Porter, Ryan

    2013-01-01

    A variety of astronomical environments contain clouds irradiated by a combination of isotropic and beamed radiation fields. For example, molecular clouds may be irradiated by the isotropic cosmic microwave background (CMB), as well as by a nearby active galactic nucleus (AGN). These radiation fields excite atoms and molecules and produce emission in different ways. We revisit the escape probability theorem and derive a novel expression that accounts for the presence of external radiation fields. We show that when the field is isotropic the escape probability is reduced relative to that in the absence of external radiation. This is in agreement with previous results obtained under ad hoc assumptions or with the two-level system, but can be applied to complex many-level models of atoms or molecules. This treatment is in the development version of the spectral synthesis code Cloudy. We examine the spectrum of a Spitzer cloud embedded in the local interstellar radiation field, and show that about 60 percent of it...

  11. Cosmic expansion history from SN Ia data via information field theory

    CERN Document Server

    Porqueres, Natàlia; Greiner, Maksim; Böhm, Vanessa; Dorn, Sebastian; Ruiz-Lapuente, Pilar; Manrique, Alberto

    2016-01-01

    We present a novel inference algorithm that reconstructs the cosmic expansion history as encoded in the Hubble parameter $H(z)$ from SNe Ia data. The novelty of the approach lies in the usage of information field theory, a statistical field theory that is very well suited for the construction of optimal signal recovery algorithms. The algorithm infers non-parametrically $s(a)=\\ln(\\rho(a)/\\rho_{\\mathrm{crit}0})$, the density evolution which determines $H(z)$, without assuming an analytical form of $\\rho(a)$ but only its smoothness with the scale factor $a=(1+z)^{-1}$. The inference problem of recovering the signal $s(a)$ from the data is formulated in a fully Bayesian way. In detail, we rewrite the signal as the sum of a background cosmology and a perturbation. This allows to determine the maximum a posteriory estimate of the signal by an iterative Wiener filter method. Applying this method to the Union2.1 supernova compilation, we recover a cosmic expansion history that is fully compatible with the standard $...

  12. Voyager Observations of Magnetic Fields and Cosmic Rays in the Heliosheath

    Science.gov (United States)

    Burlaga, L. F.; Ness, N. F.; Stone, E.; McDonald, F. B.

    2011-01-01

    The major features of the profile of greater than 70 MeV/nuc cosmic ray intensity (CRI) observed by Voyager 1 (VI) in the heliosheath from 2005.8-2010.24 are described by the empirical "CR-B" relation as the cumulative effect of variations of the magnetic field strength B. The CRI profile observed by Voyager 2 (V2) from 2008.60 to 2010.28 in the heliosheath is also described by the CR-B relation. On a smaller scale, of the order of a hundred days, a sequence on CRI decreases observed by V 1 during 2006 was interpreted as the effect of a propagating interplanetary shock first interacting with the termination shock, then moving past V1, and finally reflecting from the heliopause and propagating back to V1. Our observations show that the second CRI decrease in this sequence began during the passage of a "Global Merged Interaction Region" (GMIR), 40 days after the arrival of the GMIR and its possible shock. The first and third CRI decreases in the sequence were associated with local enhancements of B. The magnetic field observations associated with the second sequence of 3 cosmic ray intensity decreases observed by V 1 in 2007/2008 are more difficult to reconcile with the scenario of Webber et al. (2009) and the CR-B relation. The discrepancy might indicate the importance of latitudinal effects

  13. On the possible origin of the large scale cosmic magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Coroniti, F. V. [Department of Physics and Astronomy, University of California, 430 Portola Plaza, Los Angeles, CA 90095-1547 (United States)

    2014-01-10

    The possibility that the large scale cosmic magnetic field is directly generated at microgauss, equipartition levels during the reionization epoch by collisionless shocks that are forced to satisfy a downstream shear flow boundary condition is investigated through the development of two models—the accretion of an ionized plasma onto a weakly ionized cool galactic disk and onto a cool filament of the cosmic web. The dynamical structure and the physical parameters of the models are synthesized from recent cosmological simulations of the early reionization era after the formation of the first stars. The collisionless shock stands upstream of the disk and filament, and its dissipation is determined by ion inertial length Weibel turbulence. The downstream shear boundary condition is determined by the rotational neutral gas flow in the disk and the inward accretion flow along the filament. The shocked plasma is accelerated to the downstream shear flow velocity by the Weibel turbulence, and the relative shearing motion between the electrons and ions produces a strong, ion inertial scale current sheet that generates an equipartition strength, large scale downstream magnetic field, ∼10{sup –6} G for the disk and ∼6 × 10{sup –8} G for the filament. By assumption, hydrodynamic turbulence transports the shear-shock generated magnetic flux throughout the disk and filament volume.

  14. Cosmic Web of Galaxies in the COSMOS Field: Public Catalog and Different Quenching for Centrals and Satellites

    CERN Document Server

    Darvish, Behnam; Martin, D Christopher; Sobral, David; Scoville, Nick Z; Stroe, Andra; Hemmati, Shoubaneh; Kartaltepe, Jeyhan

    2016-01-01

    We use a mass complete (log($M/M_{\\odot}$) $\\geqslant$ 9.6) sample of galaxies with accurate photometric redshifts in the COSMOS field to construct the density field and the cosmic web to $z$=1.2. The comic web extraction relies on the density field Hessian matrix and breaks the density field into clusters, filaments and the field. We provide the density field and cosmic web measures to the community. We show that at $z$ $\\lesssim$ 0.8, the median star-formation rate (SFR) in the cosmic web gradually declines from the field to clusters and this decline is especially sharp for satellites ($\\sim$ 1 dex vs. $\\sim$ 0.5 dex for centrals). However, at $z$ $\\gtrsim$ 0.8, the trend flattens out for the overall galaxy population and satellites. For star-forming galaxies only, the median SFR is constant at $z$ $\\gtrsim$ 0.5 but declines by $\\sim$ 0.3-0.4 dex from the field to clusters for satellites and centrals at $z$ $\\lesssim$ 0.5. We argue that for satellites, the main role of the cosmic web environment is to contr...

  15. TeV Cosmic-Ray Anisotropy from the Magnetic Field at the Heliospheric Boundary

    CERN Document Server

    López-Barquero, Vanessa; Desiati, P; Lazarian, A; Pogorelov, N V; Yan, H

    2016-01-01

    We performed numerical calculations to test the suggestion by Desiati & Lazarian (2013) that the anisotropies of TeV cosmic rays may arise from their interactions with the heliosphere. For this purpose, we used a magnetic field model of the heliosphere and performed direct numerical calculations of particle trajectories. Unlike earlier papers testing the idea, we did not employ time-reversible techniques that are based on Liouville's theorem. We showed numerically that for scattering by the heliosphere the conditions of Liouville's theorem are not satisfied and the adiabatic approximation and time-reversibility of the particle trajectories are not valid. Our results indicate sensitivity to the magnetic structure of the heliospheric magnetic field, and we expect that this will be useful for probing this structure in future research.

  16. Excitation of magnetization using a modulated radiation damping field.

    Science.gov (United States)

    Walls, Jamie D; Huang, Susie Y; Lin, Yung-Ya

    2006-10-12

    In this work, pulsed-field gradients are used to modulate the radiation damping field generated by the detection coil in an NMR experiment in order that spins with significantly different chemical shifts can affect one another via the radiation damping field. Experiments performed on solutions of acetone/water and acetone/DMSO/water demonstrate that spins with chemical shift differences much greater than the effective radiation damping field strength can still be coupled by modulating the radiation damping field. Implications for applications in high-field NMR and for developing sensitive magnetization detectors are discussed.

  17. Cosmic Dawn (CoDa): the First Radiation-Hydrodynamics Simulation of Reionization and Galaxy Formation in the Local Universe

    Science.gov (United States)

    Ocvirk, Pierre; Gillet, Nicolas; Shapiro, Paul R.; Aubert, Dominique; Iliev, Ilian T.; Teyssier, Romain; Yepes, Gustavo; Choi, Jun-Hwan; Sullivan, David; Knebe, Alexander; Gottlöber, Stefan; D'Aloisio, Anson; Park, Hyunbae; Hoffman, Yehuda; Stranex, Timothy

    2016-12-01

    Cosmic reionization by starlight from early galaxies affected their evolution, thereby impacting reionization itself. Star formation suppression, for example, may explain the observed underabundance of Local Group dwarfs relative to N-body predictions for cold dark matter. Reionization modelling requires simulating volumes large enough [˜ (100 Mpc)3] to sample reionization `patchiness', while resolving millions of galaxy sources above ˜108 M⊙ combining gravitational and gas dynamics with radiative transfer. Modelling the Local Group requires initial cosmological density fluctuations pre-selected to form the well-known structures of the Local Universe today. Cosmic Dawn (`CoDa') is the first such fully coupled, radiation-hydrodynamics simulation of reionization of the Local Universe. Our new hybrid CPU-GPU code, RAMSES-CUDATON, performs hundreds of radiative transfer and ionization rate-solver timesteps on the GPUs for each hydro-gravity timestep on the CPUs. CoDa simulated (91Mpc)3 with 40963 particles and cells, to redshift 4.23, on ORNL supercomputer Titan, utilizing 8192 cores and 8192 GPUs. Global reionization ended slightly later than observed. However, a simple temporal rescaling which brings the evolution of ionized fraction into agreement with observations also reconciles ionizing flux density, cosmic star formation history, CMB electron scattering optical depth and galaxy UV luminosity function with their observed values. Photoionization heating suppressed the star formation of haloes below ˜2 × 109 M⊙, decreasing the abundance of faint galaxies around MAB1600 = [-10, -12]. For most of reionization, star formation was dominated by haloes between 1010-1011 M⊙ , so low-mass halo suppression was not reflected by a distinct feature in the global star formation history. Intergalactic filaments display sheathed structures, with hot envelopes surrounding cooler cores, but do not self-shield, unlike regions denser than 100 .

  18. Cosmic Dawn (CoDa): the First Radiation-Hydrodynamics Simulation of Reionization and Galaxy Formation in the Local Universe

    Science.gov (United States)

    Ocvirk, Pierre; Gillet, Nicolas; Shapiro, Paul R.; Aubert, Dominique; Iliev, Ilian T.; Teyssier, Romain; Yepes, Gustavo; Choi, Jun-Hwan; Sullivan, David; Knebe, Alexander; Gottlöber, Stefan; D'Aloisio, Anson; Park, Hyunbae; Hoffman, Yehuda; Stranex, Timothy

    2016-08-01

    Cosmic reionization by starlight from early galaxies affected their evolution, thereby impacting reionization, itself. Star formation suppression, for example, may explain the observed underabundance of Local Group dwarfs relative to N-body predictions for Cold Dark Matter. Reionization modelling requires simulating volumes large enough [ ˜ (100 Mpc)3] to sample reionization "patchiness", while resolving millions of galaxy sources above ˜108 M⊙ , combining gravitational and gas dynamics with radiative transfer. Modelling the Local Group requires initial cosmological density fluctuations pre-selected to form the well-known structures of the local universe today. Cosmic Dawn ("CoDa") is the first such fully-coupled, radiation-hydrodynamics simulation of reionization of the local universe. Our new hybrid CPU-GPU code, RAMSES-CUDATON, performs hundreds of radiative transfer and ionization rate-solver timesteps on the GPUs for each hydro-gravity timestep on the CPUs. CoDa simulated (91Mpc)3 with 40963 particles and cells, to redshift 4.23, on ORNL supercomputer Titan, utilizing 8192 cores and 8192 GPUs. Global reionization ended slightly later than observed. However, a simple temporal rescaling which brings the evolution of ionized fraction into agreement with observations also reconciles ionizing flux density, cosmic star formation history, CMB electron scattering optical depth and galaxy UV luminosity function with their observed values. Photoionization heating suppressed the star formation of haloes below ˜2 × 109 M⊙ , For most of reionization, star formation was dominated by haloes between 1010 - 1011 M⊙ , so low-mass halo suppression was not reflected by a distinct feature in the global star formation history. Intergalactic filaments display sheathed structures, with hot envelopes surrounding cooler cores, but do not self-shield, unlike regions denser than 100 .

  19. Bulk gravitational field and dark radiation on the brane in dilatonic brane world

    CERN Document Server

    Yoshiguchi, H; Yoshiguchi, Hiroyuki; Koyama, Kazuya

    2004-01-01

    We discuss the connection between the dark radiation on the brane and the bulk gravitational field in a dilatonic brane world model proposed by Koyama and Takahashi where the exact solutions for the five dimensional cosmological perturbations can be obtained analytically. It is shown that the dark radiation perturbation is related to the non-normalizable Kaluza-Klein (KK) mode of the bulk perturbations. For the de Sitter brane in the anti-de Sitter bulk, the squared mass of this KK mode is $2 H^2$ where $H$ is the Hubble parameter on the brane. This mode is shown to be connected to the excitation of small black hole in the bulk in the long wavelength limit. The exact solution for an anisotropic stress on the brane induced by this KK mode is found, which plays an important role in the calculation of cosmic microwave background radiation anisotropies in the brane world.

  20. Atmospheric electric field effects of cosmic rays detected in Mexico City

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, L. X; Valdes-Galicia, J. F [Instituto de Geofisica, Universidad National Autonoma de Mexico, Mexico D.F(Mexico)

    2006-10-15

    We studied the possible effects of atmospheric electric fields, generated in thunderstorms, on the cosmic ray intensity detected at the Earth's surface by investigating the variations of the counting rates of the cosmic-ray nucleonic component, obtained from the neutron monitor installed in Mexico City, for thunderstorms during 1996 and 1997. These were years of minimum solar activity. We compare our experimental results with the general theory of cosmic ray meteorological effects by Dorman (1995). The observed intensity variation is about 0.2%. According to Dorman (1995), the effect should be between 0.27% and 0.81% on the counting rate of the neutron monitor when the atmospheric electric field intensities are around 100 to 300 Vcm-1.Our results show that either the electric field in Mexico City had less intensity than assumed by Dorman (1995), or the electric field is not uniform in time and height during the development of the thunderstorm. [Spanish] Estudiamos los posibles efectos de los campos electricos atmosfericos, generados en las tormentas electricas, sobre la intensidad de los rayos cosmicos detectados en la superficie terrestre, analizando las variaciones de las razones de conteo de la componente nucleonica de los rayos cosmicos, obtenidas por el monitor de neutrones instalado en la ciudad de Mexico, durante tormentas electricas ocurridas entre 1996 y 1997, anos del minimo solar. Comparamos nuestros resultados experimentales con la teoria general de los efectos meteorologicos en los rayos cosmicos, desarrollada por Dorman (1995). Se observo una variacion en la intensidad de alrededor de 0.2%. De acuerdo con Dorman (1995), el efecto puede estar entre 0.27 % y 0.81% en las razones de conteo del monitor de neutrones cuando las intensidades del campo electrico atmosferico se encuentran al rededor de 100 a 300 Vcm-1. Nuestros resultados muestran que los campos electricos en la ciudad de Mexico tuvieron menos intensidad que los campos electricos asumidos

  1. Cosmological consequences of classical flavor-space locked gauge field radiation

    Science.gov (United States)

    Bielefeld, Jannis; Caldwell, Robert R.

    2015-06-01

    We propose a classical SU(2) gauge field in a flavor-space locked configuration as a species of radiation in the early Universe and show that it would have a significant imprint on a primordial stochastic gravitational wave spectrum. In the flavor-space locked configuration, the electric and magnetic fields of each flavor are parallel and mutually orthogonal to other flavors, with isotropic and homogeneous stress energy. Due to the non-Abelian coupling, the gauge field breaks the symmetry between left- and right-circularly polarized gravitational waves. This broken chiral symmetry results in a unique signal: nonzero cross-correlation of the cosmic microwave background temperature and polarization, T B and E B , both of which should be zero in the standard, chiral symmetric case. We forecast the ability of current and future cosmic microwave background experiments to constrain this model. Furthermore, a wide range of behavior is shown to emerge, depending on the gauge field coupling, abundance, and allocation into electric and magnetic field energy density. The fluctuation power of primordial gravitational waves oscillates back and forth into fluctuations of the gauge field. In certain cases, the gravitational wave spectrum is shown to be suppressed or amplified by up to an order of magnitude depending on the initial conditions of the gauge field.

  2. The discrimination between cosmic positrons and protons with the Transition Radiation Detector of the AMS experiment on the International Space Station

    Energy Technology Data Exchange (ETDEWEB)

    Millinger, Mark

    2012-10-08

    The aim of this thesis is the development and validation of a particle identification method with the Transition Radiation Detector (TRD) of the Alpha Magnetic Spectrometer AMS-02 to allow for the determination of the positron fraction in the cosmic lepton flux. Independent measurements indicate that a significant amount of about 23% of the energy density in the universe consists of an unknown mass contribution, the so-called Dark Matter. The Neutralino, as the most popular Dark Matter particle candidate, may produce an additional signal in the spectrum of cosmic rays. The fraction of positrons in the cosmic lepton flux possibly contains such a Dark Matter signal at high particle momenta. The currently most precise measurements in the region of this excess are provided by the satellite-borne PAMELA and Fermi detectors. Momentumdependent systematic uncertainties, especially the mis-identification of protons as positrons, could imitate the signal. However, if this positron excess is produced by Dark Matter the fraction should decrease above a theoretical energy threshold to the expectations, based on particle propagation. The energy region measured up to now does not show such a progress. Due to its significantly increased event statistics and its capability to measure up to higher particle energies, this signature could be observed with AMS-02. The number of events, which can be recorded by a detector, is limited by the combination of aperture and observable solid angle, quantified by the geometrical acceptance, and the observation time. As the cosmic particle flux follows a power-law in particle momentum with exponent {gamma} {approx} -3, the observable momentum interval is thus constrained by statistics. Due to its large geometrical acceptance of about 0.5 m{sup 2}sr, its long observation time of at least 9 years and its high proton suppression factor of >or similar 10{sup 6} AMS-02 will record large and clean lepton samples and thus provide a precise measurement

  3. Searching for high energy cosmic ray electrons using the Earth's magnetic field.

    Science.gov (United States)

    Nutter, S.; Bower, C.; Coutu, S.; Duvernois, M.; Martell, A.; Muller, D.; Musser, J.; Schubnell, M.; Tarle, G.; Yagi, A.

    2006-04-01

    The Cosmic Ray Electron Synchrotron Telescope (CREST) instrument is a balloon payload designed to measure the flux of primary cosmic ray electrons at energies greater than 2 TeV. Because electrons at these energies lose energy rapidly during propagation through the interstellar medium, their detection would indicate the existence of sources which are within a few kiloparsecs. In order to obtain the needed large exposure time and aperture of the detector, we use an approach that depends on the detection of synchrotron photons emitted when the electrons travel through the earth's magnetic field. Such photons have energies in the x-ray and gamma-ray region, hence CREST incorporates an array of inorganic scintillators. Since the primary electrons do not need to pass through the detector, the effective detection area is much larger than the actual detector array size. To verify the technique and to determine background count rates, a prototype array of BGO and BaF2 crystals was flown on high altitude balloon from Ft. Sumner, N.M. in autumn 2005. The full detector system is currently under construction. It will consist of a 1600 crystal array, and will be carried on Long-Duration Balloons on circumpolar trajectory.

  4. Cosmic Web of Galaxies in the COSMOS Field: Public Catalog and Different Quenching for Centrals and Satellites

    Science.gov (United States)

    Darvish, Behnam; Mobasher, Bahram; Martin, D. Christopher; Sobral, David; Scoville, Nick; Stroe, Andra; Hemmati, Shoubaneh; Kartaltepe, Jeyhan

    2017-03-01

    We use a mass complete (log(M/{M}ȯ ) ≥slant 9.6) sample of galaxies with accurate photometric redshifts in the COSMOS field to construct the density field and the cosmic web to z = 1.2. The comic web extraction relies on the density field Hessian matrix and breaks the density field into clusters, filaments, and the field. We provide the density field and cosmic web measures to the community. We show that at z ≲ 0.8, the median star formation rate (SFR) in the cosmic web gradually declines from the field to clusters and this decline is especially sharp for satellites (∼1 dex versus ∼0.5 dex for centrals). However, at z ≳ 0.8, the trend flattens out for the overall galaxy population and satellites. For star-forming (SF) galaxies only, the median SFR is constant at z ≳ 0.5 but declines by ∼0.3–0.4 dex from the field to clusters for satellites and centrals at z ≲ 0.5. We argue that for satellites, the main role of the cosmic web environment is to control their SF fraction, whereas for centrals, it is mainly to control their overall SFR at z ≲ 0.5 and to set their fraction at z ≳ 0.5. We suggest that most satellites experience a rapid quenching mechanism as they fall from the field into clusters through filaments, whereas centrals mostly undergo a slow environmental quenching at z ≲ 0.5 and a fast mechanism at higher redshifts. Our preliminary results highlight the importance of the large-scale cosmic web on galaxy evolution.

  5. Temperature field for radiative tomato peeling

    Science.gov (United States)

    Cuccurullo, G.; Giordano, L.

    2017-01-01

    Nowadays peeling of tomatoes is performed by using steam or lye, which are expensive and polluting techniques, thus sustainable alternatives are searched for dry peeling and, among that, radiative heating seems to be a fairly promising method. This paper aims to speed up the prediction of surface temperatures useful for realizing dry-peeling, thus a 1D-analytical model for the unsteady temperature field in a rotating tomato exposed to a radiative heating source is presented. Since only short times are of interest for the problem at hand, the model involves a semi-infinite slab cooled by convective heat transfer while heated by a pulsating heat source. The model being linear, the solution is derived following the Laplace Transform method. A 3D finite element model of the rotating tomato is introduced as well in order to validate the analytical solution. A satisfactory agreement is attained. Therefore, two different ways to predict the onset of the peeling conditions are available which can be of help for proper design of peeling plants. Particular attention is paid to study surface temperature uniformity, that being a critical parameter for realizing an easy tomato peeling.

  6. Evolution of Mass and Velocity Field in the Cosmic Web: Comparison between Baryonic and Dark Matter

    Science.gov (United States)

    Zhu, Weishan; Feng, Long-Long

    2017-03-01

    We investigate the evolution of the cosmic web since z = 5 in grid-based cosmological hydrodynamical simulations, focusing on the mass and velocity fields of both baryonic and cold dark matter. The tidal tensor of density is used as the main method for web identification, with λ th = 0.2–1.2. The evolution trends in baryonic and dark matter are similar, although moderate differences are observed. Sheets appear early, and their large-scale pattern may have been set up by z = 3. In terms of mass, filaments supersede sheets as the primary collapsing structures from z ∼ 2–3. Tenuous filaments assembled with each other to form prominent ones at z < 2. In accordance with the construction of the frame of the sheets, the cosmic divergence velocity, v div, was already well-developed above 2–3 Mpc by z = 3. Afterwards, the curl velocity, v curl, grew dramatically along with the rising of filaments, becoming comparable to v div, for <2–3 Mpc at z = 0. The scaling of v curl can be described by the hierarchical turbulence model. The alignment between the vorticity and the eigenvectors of the shear tensor in the baryonic matter field resembles that in the dark matter field, and is even moderately stronger between {\\boldsymbol{ω }} and {{\\boldsymbol{e}}}1, and ω and {{\\boldsymbol{e}}}3. Compared with dark matter, there is slightly less baryonic matter found residing in filaments and clusters, and its vorticity developed more significantly below 2–3 Mpc. These differences may be underestimated because of the limited resolution and lack of star formation in our simulation. The impact of the change of dominant structures in overdense regions at z ∼ 2–3 on galaxy formation and evolution is shortly discussed.

  7. Cosmic rays: a review for astrobiologists.

    Science.gov (United States)

    Ferrari, Franco; Szuszkiewicz, Ewa

    2009-05-01

    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.

  8. Inhomogeneous extragalactic magnetic fields and the second knee in the cosmic ray spectrum

    CERN Document Server

    Kotera, Kumiko

    2007-01-01

    Various experiments indicate the existence of a second knee around energy E=3 10^{17} eV in the cosmic ray spectrum. This feature could be the signature of the end of the galactic component and of the emergence of the extragalactic one, provided that the latter cuts off at low energies. Recent analytical calculations have shown that this cut-off could be a consequence of the existence of extragalactic magnetic fields: low energy protons diffuse on extragalactic magnetic fields and cannot reach the observer within a given time. We study the influence of inhomogeneous magnetic fields on the magnetic horizon, using a newly written original semi-analytical propagation code. Our results indicate that, at a fixed value of the volume averaged magnetic field , the amplitude of the low energy cut-off is mainly controled by the strength of magnetic fields in the voids of the large scale structure distribution. Our simulations also enable us to constrain some crucial parameters: should be greater than 0.3 nG and not ex...

  9. Future Observations of Cosmic Magnetic Fields with the SKA and its Precursors

    CERN Document Server

    Beck, Rainer

    2011-01-01

    The origin of magnetic fields in the Universe is an open problem in astrophysics and fundamental physics. Polarization observations with the forthcoming large radio telescopes, especially the Square Kilometre Array (SKA), will open a new era in the observation of magnetic fields and should help to understand their origin. Low-frequency radio synchrotron emission, to be observed with LOFAR, MWA and the SKA, traces low-energy cosmic ray electrons and allows us to map the structure of weak magnetic fields in the outer regions and halos of galaxies, in halos and relics of galaxy clusters and in the Milky Way. Polarization at higher frequencies (1-10 GHz), to be observed with the SKA and its precursors ASKAP and MeerKAT, will trace magnetic fields in the disks and central regions of galaxies and in cluster relics in unprecedented detail. All-sky surveys of Faraday rotation measures towards a dense grid of polarized background sources with ASKAP (project POSSUM) and the SKA are dedicated to measure magnetic fields ...

  10. Force-field parameterization of the galactic cosmic ray spectrum: Validation for Forbush decreases

    Science.gov (United States)

    Usoskin, I. G.; Kovaltsov, G. A.; Adriani, O.; Barbarino, G. C.; Bazilevskaya, G. A.; Bellotti, R.; 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.; 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.; Panico, B.; 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.; Stozhkov, Y. I.; Vacchi, A.; Vannuccini, E.; Vasilyev, G. I.; Voronov, S. A.; Yurkin, Y. T.; Zampa, G.; Zampa, N.; Zverev, V. G.

    2015-06-01

    A useful parametrization of the energy spectrum of galactic cosmic rays (GCR) near Earth is offered by the so-called force-field model which describes the shape of the entire spectrum with a single parameter, the modulation potential. While the usefulness of the force-field approximation has been confirmed for regular periods of solar modulation, it was not tested explicitly for disturbed periods, when GCR are locally modulated by strong interplanetary transients. Here we use direct measurements of protons and α -particles performed by the PAMELA space-borne instrument during December 2006, including a major Forbush decrease, in order to directly test the validity of the force-field parameterization. We conclude that (1) The force-field parametrization works very well in describing the energy spectra of protons and α -particles directly measured by PAMELA outside the Earths atmosphere; (2) The energy spectrum of GCR can be well parameterized by the force-field model also during a strong Forbush decrease; (3) The estimate of the GCR modulation parameter, obtained using data from the world-wide neutron monitor network, is in good agreement with the spectra directly measured by PAMELA during the studied interval. This result is obtained on the basis of a single event analysis, more events need to be analyzed.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-07-01

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

  12. Structural analysis of the SDSS Cosmic Web - I. Non-linear density field reconstructions

    Science.gov (United States)

    Platen, Erwin; van de Weygaert, Rien; Jones, Bernard J. T.; Vegter, Gert; Calvo, Miguel A. Aragón

    2011-10-01

    This study is the first in a series in which we analyse the structure and topology of the Cosmic Web as traced by the Sloan Digital Sky Survey (SDSS). The main issue addressed in the present study is the translation of the irregularly distributed discrete spatial data in the galaxy redshift survey into a representative density field. The density field will form the basis for a statistical, topological and cosmographic study of the cosmic density field in our Local Universe. We investigate the ability of three reconstruction techniques to analyse and investigate web-like features and geometries in a discrete distribution of objects. The three methods are the linear Delaunay Tessellation Field Estimator (DTFE), its higher order equivalent Natural Neighbour Field Estimator (NNFE) and a version of the Kriging interpolation adapted to the specific circumstances encountered in galaxy redshift surveys, the Natural Lognormal Kriging technique. DTFE and NNFE are based on the local geometry defined by the Voronoi and Delaunay tessellations of the galaxy distribution. The three reconstruction methods are analysed and compared using mock magnitude- and volume-limited SDSS redshift surveys, obtained on the basis of the Millennium simulation. We investigate error trends, biases and the topological structure of the resulting fields, concentrating on the void population identified by the Watershed Void Finder. Environmental effects are addressed by evaluating the density fields on a range of Gaussian filter scales. Comparison with the void population in the original simulation yields the fraction of false void mergers and false void splits. In most tests DTFE, NNFE and Kriging have largely similar density and topology error behaviour. Cosmetically, higher order NNFE and Kriging methods produce more visually appealing reconstructions. Quantitatively, however, DTFE performs better, even while being computationally far less demanding. A successful recovery of the void population on

  13. Study on CYCIAE-100 radiation field and residual radioactivity

    Institute of Scientific and Technical Information of China (English)

    BI Yuan-Jie; ZHANG Tian-Jue; JIA Xian-Lu; ZHOU Zheng-He; WANG Feng; WEI Su-Min; ZHONG Jun-Qing; TANG Chuan-Xiang

    2009-01-01

    The accelerators should be properly designed to make the radiation field produced by beam loss ual radiation field.The induced radioactivity in accelerator components is the dominant source of occupational radiation exposure if the accelerator is well shielded.The source of radiation is the beam loss when cyclotron is operating.In this paper,the radiation field for CYCIAE-100 is calculated using Monte Carlo method and the radioactive contamination near stripping foil is studied.A method to reduce the dose equivalent rate of maintenance staff is also given.

  14. On the possibility of cosmic ray-induced ionizing radiation-powered life in subsurface environments in the Universe

    CERN Document Server

    Atri, Dimitra

    2015-01-01

    Photosynthesis is a highly efficient mechanism developed by terrestrial life to utilize the energy from photons of solar origin for biological use. Subsurface regions are isolated from the photosphere, and consequently are incapable of utilizing this energy. This opens up the opportunity for life to cultivate alternative mechanisms in order to take advantage of other available energy sources. Studies have shown that in subsurface environments, life can use energy generated from geochemical and geothermal processes to sustain a minimal metabolism. Another mechanism is radiolysis, in which particles emitted by radioactive substances are indirectly utilized for metabolism. One such example is the bacterium fueled by radiation, found 2 miles deep in a South African mine, which consumes hydrogen formed from particles emitted by radioactive U, Th and K present in rock. An additional source of radiation in the subsurface environments is secondary particles, such as muons generated by Galactic Cosmic Rays (GCRs). It ...

  15. The Cosmic Infrared Background Experiment (CIBER): The Wide-Field Imagers

    CERN Document Server

    Bock, J; Arai, T; Battle, J; Cooray, A; Hristov, V; Keating, B; Kim, M G; Lam, A C; Lee, D H; Levenson, L R; Mason, P; Matsumoto, T; Matsuura, S; Mitchell-Wynne, K; Nam, U W; Renbarger, T; Smidt, J; Suzuki, K; Tsumura, K; Wada, T; Zemcov, M

    2012-01-01

    We have developed and characterized an imaging instrument to measure the spatial properties of the diffuse near-infrared extragalactic background light in a search for fluctuations from z > 6 galaxies during the epoch of reionization. The instrument is part of the Cosmic Infrared Background Experiment (CIBER), designed to observe the extragalactic background light above the Earth's atmosphere during a suborbital sounding rocket flight. The imaging instrument incorporates a 2x2 degree field of view, to measure fluctuations over the predicted peak of the spatial power spectrum at 10 arcminutes, and 7"x7" pixels, to remove lower redshift galaxies to a depth sufficient to reduce the low-redshift galaxy clustering foreground below instrumental sensitivity. The imaging instrument employs two cameras with \\Delta \\lambda / \\lambda ~0.5 bandpasses centered at 1.1 and 1.6 microns to spectrally discriminate reionization extragalactic background fluctuations from local foreground fluctuations. CIBER operates at wavelengt...

  16. Extra-galactic magnetic fields and the second knee in the cosmic-ray spectrum

    CERN Document Server

    Lemoine, M

    2004-01-01

    Recent work suggests that the cosmic ray spectrum may be dominated by Galactic sources up to ~10^{17.5} eV, and by an extra-Galactic component beyond, provided this latter cuts off below the transition energy. Here it is shown that this cut-off could be interpreted as a signature of extra-galactic magnetic fields with equivalent average strength B and coherence length l_c such that B\\sqrt{l_c}~2.10^{-10} G.Mpc^{1/2}, assuming l_c < r_L (Larmor radius at 10^{17} eV) and continuously emitting sources with density 10^{-5}/Mpc^3. The extra-Galactic flux is suppressed below 10^{17} eV as the diffusive propagation time from the source to the detector becomes larger than the age of the Universe.

  17. Effects of a primordial magnetic field with log-normal distribution on the cosmic microwave background

    CERN Document Server

    Yamazaki, Dai G; Takahashi, Keitaro; 10.1103/PhysRevD.84.123006

    2011-01-01

    We study the effect of primordial magnetic fields (PMFs) on the anisotropies of the cosmic microwave background (CMB). We assume the spectrum of PMFs is described by log-normal distribution which has a characteristic scale, rather than power-law spectrum. This scale is expected to reflect the generation mechanisms and our analysis is complementary to previous studies with power-law spectrum. We calculate power spectra of energy density and Lorentz force of the log-normal PMFs, and then calculate CMB temperature and polarization angular power spectra from scalar, vector, and tensor modes of perturbations generated from such PMFs. By comparing these spectra with WMAP7, QUaD, CBI, Boomerang, and ACBAR data sets, we find that the current CMB data set places the strongest constraint at $k\\simeq 10^{-2.5}$ Mpc$^{-1}$ with the upper limit $B\\lesssim 3$ nG.

  18. Dynamic Cosmic Strings Numerical evolution of excited Cosmic Strings

    CERN Document Server

    Sperhake, U; Vickers, J A

    2001-01-01

    An implicit, fully characteristic, numerical scheme for solving the field equations of a cosmic string coupled to gravity is described. The inclusion of null infinity as part of the numerical grid allows us to apply suitable boundary conditions on the metric and matter fields to suppress unphysical divergent solutions. The code is tested by comparing the results with exact solutions, checking that static cosmic string initial data remain constant when evolved and undertaking a time dependent convergence analysis of the code. It is shown that the code is accurate, stable and exhibits clear second order convergence. The code is used to analyse the interaction between a Weber--Wheeler pulse of gravitational radiation with the string. The interaction causes the string to oscillate at frequencies inversely proportional to the masses of the scalar and vector fields of the string. After the pulse has largely radiated away the string continues to ring but the oscillations slowly decay and eventually the variables ret...

  19. A Macroscopic Description of Coherent Geo-Magnetic Radiation from Cosmic Rays

    NARCIS (Netherlands)

    Scholten, O.; Werner, K.; Caballero, Rogelio; D'Olivo, Juan Carlos; Medina-Tanco, Gustavo; Nellen, Lukas; Sánchez, Federico A.; Valdés-Galicia, José F.

    2008-01-01

    In an air shower induced by a cosmic ray, due to the high velocities, most of the particles are concentrated in the relatively thin shower front, which, for obvious reasons, is called the 'pancake'. This pancake, which for the present discussion is assumed to be charge neutral, contains large

  20. Measurement of 0.25-3.2 GeV antiprotons in the cosmic radiation

    DEFF Research Database (Denmark)

    Mitchell, J.W.; Barbier, L.M.; Christian, E.R.

    1996-01-01

    The balloon-borne Isotope Matter-Antimatter Experiment (IMAX) was flown from Lynn Lake, Manitoba, Canada on 16-17 July 1992. Using velocity and magnetic rigidity to determine mass, we have directly measured the abundances of cosmic ray antiprotons and protons in the energy range from 0.25 to 3.2 ...

  1. A Macroscopic Description of Coherent Geo-Magnetic Radiation from Cosmic Rays

    NARCIS (Netherlands)

    Scholten, O.; Werner, K.; Caballero, Rogelio; D'Olivo, Juan Carlos; Medina-Tanco, Gustavo; Nellen, Lukas; Sánchez, Federico A.; Valdés-Galicia, José F.

    2008-01-01

    In an air shower induced by a cosmic ray, due to the high velocities, most of the particles are concentrated in the relatively thin shower front, which, for obvious reasons, is called the 'pancake'. This pancake, which for the present discussion is assumed to be charge neutral, contains large number

  2. Cosmic rays and particle physics

    CERN Document Server

    Gaisser, Thomas K; Resconi, Elisa

    2016-01-01

    Fully updated for the second edition, this book introduces the growing and dynamic field of particle astrophysics. It provides an overview of high-energy nuclei, photons and neutrinos, including their origins, their propagation in the cosmos, their detection on Earth and their relation to each other. Coverage is expanded to include new content on high energy physics, the propagation of protons and nuclei in cosmic background radiation, neutrino astronomy, high-energy and ultra-high-energy cosmic rays, sources and acceleration mechanisms, and atmospheric muons and neutrinos. Readers are able to master the fundamentals of particle astrophysics within the context of the most recent developments in the field. This book will benefit graduate students and established researchers alike, equipping them with the knowledge and tools needed to design and interpret their own experiments and, ultimately, to address a number of questions concerning the nature and origins of cosmic particles that have arisen in recent resea...

  3. Study of the contribution of the different components of atmospheric cosmic radiation in dose received by the aircraft crew; Avaliacao da contribuicao dos diferentes componentes da radiacao cosmica atmosferica na dose em tripulacoes de aeronaves

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Marlon A.; Prado, Adriane C.M., E-mail: adriane.acm@hotmail.com, E-mail: marlon@ieav.cta.br [Instituto Tecnologico de Aeronautica (ITA/DCTA), Sao Jose dos Campos, SP (Brazil); Federico, Claudio A.; Goncalez, Odair L., E-mail: claudiofederico@ieav.cta.br, E-mail: odairl@ieav.cta.br [Instituto de Estudos Avancados (IEAv/DCTA), Sao Jose dos Campos, SP (Brazil)

    2014-07-01

    The crews and aircraft passengers are exposed to atmospheric cosmic radiation. The flow of this radiation is modulated by the solar cycle and space weather, varying with the geomagnetic latitude and altitude. This paper presents a study of the contributions of radiation in total ambient dose equivalent of the crews depending on flight altitude up to 20 km, during maximum and minimum solar and in equatorial and polar regions. The results of calculations of the particle flows generated by the EXPACS and QARM codes are used. The particles evaluated that contributing significantly in the ambient dose equivalent are neutrons, protons, electrons, positrons, alphas, photons, muons and charged pions. This review allows us to characterize the origin of the dose received by crews and also support a project of a dosimetric system suitable for this ionizing radiation field in aircraft and on the ground.

  4. Vacuum radiation induced by time dependent electric field

    Directory of Open Access Journals (Sweden)

    Bo Zhang

    2017-04-01

    Full Text Available Many predictions of new phenomena given by strong field quantum electrodynamics (SFQED will be tested on next generation multi-petawatt laser facilities in the near future. These new phenomena are basis to understand physics in extremely strong electromagnetic fields therefore have attracted wide research interest. Here we discuss a new SFQED phenomenon that is named as vacuum radiation. In vacuum radiation, a virtual electron loop obtain energy from time dependent external electric field and radiate an entangled photon pair. Features of vacuum radiation in a locally time dependent electric field including spectrum, characteristic temperature, production rate and power are given.

  5. Vacuum radiation induced by time dependent electric field

    Science.gov (United States)

    Zhang, Bo; Zhang, Zhi-meng; Hong, Wei; He, Shu-Kai; Teng, Jian; Gu, Yu-qiu

    2017-04-01

    Many predictions of new phenomena given by strong field quantum electrodynamics (SFQED) will be tested on next generation multi-petawatt laser facilities in the near future. These new phenomena are basis to understand physics in extremely strong electromagnetic fields therefore have attracted wide research interest. Here we discuss a new SFQED phenomenon that is named as vacuum radiation. In vacuum radiation, a virtual electron loop obtain energy from time dependent external electric field and radiate an entangled photon pair. Features of vacuum radiation in a locally time dependent electric field including spectrum, characteristic temperature, production rate and power are given.

  6. Interactions of cosmic superstrings

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, Mark G.; /Fermilab

    2007-06-01

    We develop methods by which cosmic superstring interactions can be studied in detail. These include the reconnection probability and emission of radiation such as gravitons or small string loops. Loop corrections to these are discussed, as well as relationships to (p; q)-strings. These tools should allow a phenomenological study of string models in anticipation of upcoming experiments sensitive to cosmic string radiation.

  7. ACCOUNTING FOR COSMIC VARIANCE IN STUDIES OF GRAVITATIONALLY LENSED HIGH-REDSHIFT GALAXIES IN THE HUBBLE FRONTIER FIELD CLUSTERS

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, Brant E.; Stark, Dan P. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Ellis, Richard S. [Department of Astronomy, California Institute of Technology, MS 249-17, Pasadena, CA 91125 (United States); Dunlop, James S.; McLure, Ross J.; McLeod, Derek, E-mail: brant@email.arizona.edu [Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh EH9 3HJ (United Kingdom)

    2014-12-01

    Strong gravitational lensing provides a powerful means for studying faint galaxies in the distant universe. By magnifying the apparent brightness of background sources, massive clusters enable the detection of galaxies fainter than the usual sensitivity limit for blank fields. However, this gain in effective sensitivity comes at the cost of a reduced survey volume and, in this Letter, we demonstrate that there is an associated increase in the cosmic variance uncertainty. As an example, we show that the cosmic variance uncertainty of the high-redshift population viewed through the Hubble Space Telescope Frontier Field cluster Abell 2744 increases from ∼35% at redshift z ∼ 7 to ≳ 65% at z ∼ 10. Previous studies of high-redshift galaxies identified in the Frontier Fields have underestimated the cosmic variance uncertainty that will affect the ultimate constraints on both the faint-end slope of the high-redshift luminosity function and the cosmic star formation rate density, key goals of the Frontier Field program.

  8. Theorem: A Static Magnetic N-pole Becomes an Oscillating Electric N-pole in a Cosmic Axion Field

    Energy Technology Data Exchange (ETDEWEB)

    Hill, Christopher T. [Fermilab

    2016-06-15

    We show for the classical Maxwell equations, including the axion electromagnetic anomaly source term, that a cosmic axion field induces an oscillating electric N-moment for any static magnetic N-moment. This is a straightforward result, accessible to anyone who has taken a first year graduate course in electrodynamics.

  9. Maps of Dust Infrared Emission for Use in Estimation of Reddening and Cosmic Microwave Background Radiation Foregrounds

    Science.gov (United States)

    Schlegel, David J.; Finkbeiner, Douglas P.; Davis, Marc

    1998-06-01

    We present a full-sky 100 μm map that is a reprocessed composite of the COBE/DIRBE and IRAS/ISSA maps, with the zodiacal foreground and confirmed point sources removed. Before using the ISSA maps, we remove the remaining artifacts from the IRAS scan pattern. Using the DIRBE 100 and 240 μm data, we have constructed a map of the dust temperature so that the 100 μm map may be converted to a map proportional to dust column density. The dust temperature varies from 17 to 21 K, which is modest but does modify the estimate of the dust column by a factor of 5. The result of these manipulations is a map with DIRBE quality calibration and IRAS resolution. A wealth of filamentary detail is apparent on many different scales at all Galactic latitudes. In high-latitude regions, the dust map correlates well with maps of H I emission, but deviations are coherent in the sky and are especially conspicuous in regions of saturation of H I emission toward denser clouds and of formation of H2 in molecular clouds. In contrast, high-velocity H I clouds are deficient in dust emission, as expected. To generate the full-sky dust maps, we must first remove zodiacal light contamination, as well as a possible cosmic infrared background (CIB). This is done via a regression analysis of the 100 μm DIRBE map against the Leiden-Dwingeloo map of H I emission, with corrections for the zodiacal light via a suitable expansion of the DIRBE 25 μm flux. This procedure removes virtually all traces of the zodiacal foreground. For the 100 μm map no significant CIB is detected. At longer wavelengths, where the zodiacal contamination is weaker, we detect the CIB at surprisingly high flux levels of 32 +/- 13 nW m-2 sr-1 at 140 μm and of 17 +/- 4 nW m-2 sr-1 at 240 μm (95% confidence). This integrated flux ~2 times that extrapolated from optical galaxies in the Hubble Deep Field. The primary use of these maps is likely to be as a new estimator of Galactic extinction. To calibrate our maps, we assume a

  10. Clusters of Galaxies Shock Waves and Cosmic Rays

    CERN Document Server

    Ryu, D; Ryu, Dongsu; Kang, Hyesung

    2002-01-01

    Recent observations of galaxy clusters in radio and X-ray indicate that cosmic rays and magnetic fields may be energetically important in the intracluster medium. According to the estimates based on theses observational studies, the combined pressure of these two components of the intracluster medium may range between $10% \\sim 100 %$ of gas pressure, although their total energy is probably time dependent. Hence, these non-thermal components may have influenced the formation and evolution of cosmic structures, and may provide unique and vital diagnostic information through various radiations emitted via their interactions with surrounding matter and cosmic background photons. We suggest that shock waves associated with cosmic structures, along with individual sources such as active galactic nuclei and radio galaxies, supply the cosmic rays and magnetic fields to the intracluster medium and to surrounding large scale structures. In order to study 1) the properties of cosmic shock waves emerging during the larg...

  11. Polarization of radiation of electrons in highly turbulent magnetic fields

    Science.gov (United States)

    Prosekin, A. Yu.; Kelner, S. R.; Aharonian, F. A.

    2016-09-01

    We study the polarization properties of the jitter and synchrotron radiation produced by electrons in highly turbulent anisotropic magnetic fields. The net polarization is provided by the geometry of the magnetic field the directions of which are parallel to a certain plane. Such conditions may appear in the relativistic shocks during the amplification of the magnetic field through the so-called Weibel instability. While the polarization properties of the jitter radiation allows extraction of direct information on the turbulence spectrum as well as the geometry of magnetic field, the polarization of the synchrotron radiation reflects the distribution of the magnetic field over its strength. For the isotropic distribution of monoenergetic electrons, we found that the degree of polarization of the synchrotron radiation is larger than the polarization of the jitter radiation. For the power-law energy distribution of electrons the relation between the degree of polarization of synchrotron and jitter radiation depends on the spectral index of the distribution.

  12. Polarization of radiation of electrons in highly turbulent magnetic fields

    CERN Document Server

    Prosekin, A Yu; Aharonian, F A

    2016-01-01

    We study the polarization properties of the jitter and synchrotron radiation produced by electrons in highly turbulent anisotropic magnetic fields. The net polarization is provided by the geometry of the magnetic field the directions of which are parallel to a certain plane. Such conditions may appear in the relativistic shocks during the amplification of the magnetic field through the so-called Weibel instability. While the polarization properties of the jitter radiation allows extraction of direct information on the turbulence spectrum as well as the geometry of magnetic field, the polarization of the synchrotron radiation reflects the distribution of the magnetic field over its strength. For the isotropic distribution of monoenergetic electrons, we found that the degree of polarization of the synchrotron radiation is larger than the polarization of the jitter radiation. For the power-law energy distribution of electrons the relation between the degree of polarization of synchrotron and jitter radiation dep...

  13. Cosmic Rays in Thunderstorms

    Science.gov (United States)

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

    2013-04-01

    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)

  14. Light-Cone Effect of Radiation Fields in Cosmological Radiative Transfer Simulations

    CERN Document Server

    Ahn, Kyungjin

    2015-01-01

    We present a novel method to implement time-delayed propagation of radiation fields in cosmological radiative transfer simulations. Time-delayed propagation of radiation fields requires construction of retarded-time fields by tracking the location and lifetime of radiation sources along the corresponding light-cones. Cosmological radiative transfer simulations have, until now, ignored this "light-cone effect" or implemented ray-tracing methods that are computationally demanding. We show that radiative transfer calculation of the time-delayed fields can be easily achieved in numerical simulations when periodic boundary conditions are used, by calculating the time-discretized retarded-time Green's function using the Fast Fourier Transform (FFT) method and convolving it with the source distribution. We also present a direct application of this method to the long-range radiation field of Lyman-Werner band photons, which is important in the high-redshift astrophysics with first stars.

  15. Characteristic recovery times of Forbush-type decreases in the cosmic radiation. I - Observations at earth at different energies

    Science.gov (United States)

    Lockwood, J. A.; Webber, W. R.; Jokipii, J. R.

    1986-01-01

    Data on 30 asymmetric Forbush decreases recorded by the IMP spacecraft at 1 AU and the Mt. Washington neutron monitor over the period 1972-84 are examined to characterize the recovery characteristics of cosmic rays after the events. The spacecraft data are concentrated at energies of 1.7 GV, while the terrestrial instruments recorded events at 5 GV. Attention is paid to the relative amplitudes of the recorded transient decreases, the characteristic recovery times, and the energy dependence of the amplitudes and recovery time. The recovery times were found to be equal at both energy levels, supporting a concept of energy independence for the recoveries. Also, no correlations were found between the recovery times and the occurrences of a solar magnetic field reversal or with phase in the solar modulation cycle. A time-dependent, two-dimensional model is defined, which expresses the cosmic ray particle distributions as a function of the decay of the disturbance, with a small dependence on the transport parameters of the cosmic rays.

  16. Amplification of perpendicular and parallel magnetic fields by cosmic ray currents

    Science.gov (United States)

    Matthews, J. H.; Bell, A. R.; Blundell, K. M.; Araudo, A. T.

    2017-08-01

    Cosmic ray (CR) currents through magnetized plasma drive strong instabilities producing amplification of the magnetic field. This amplification helps explain the CR energy spectrum as well as observations of supernova remnants and radio galaxy hotspots. Using magnetohydrodynamic simulations, we study the behaviour of the non-resonant hybrid (NRH) instability (also known as the Bell instability) in the case of CR currents perpendicular and parallel to the initial magnetic field. We demonstrate that extending simulations of the perpendicular case to 3D reveals a different character to the turbulence from that observed in 2D. Despite these differences, in 3D the perpendicular NRH instability still grows exponentially far into the non-linear regime with a similar growth rate to both the 2D perpendicular and 3D parallel situations. We introduce some simple analytical models to elucidate the physical behaviour, using them to demonstrate that the transition to the non-linear regime is governed by the growth of thermal pressure inside dense filaments at the edges of the expanding loops. We discuss our results in the context of supernova remnants and jets in radio galaxies. Our work shows that the NRH instability can amplify magnetic fields to many times their initial value in parallel and perpendicular shocks.

  17. Evolution of Magnetic Fields and Cosmic Ray Acceleration in Supernova Remnants

    CERN Document Server

    Schure, K M; Achterberg, A; Keppens, R

    2009-01-01

    Observations show that the magnetic field in young supernova remnants (SNRs) is significantly stronger than can be expected from the compression of the circumstellar medium (CSM) by a factor of four expected for strong blast waves. Additionally, the polarization is mainly radial, which is also contrary to expectation from compression of the CSM magnetic field. Cosmic rays (CRs) may help to explain these two observed features. They can increase the compression ratio to factors well over those of regular strong shocks by adding a relativistic plasma component to the pressure, and by draining the shock of energy when CRs escape from the region. The higher compression ratio will also allow for the contact discontinuity, which is subject to the Rayleigh-Taylor (R-T) instability, to reach much further out to the forward shock. This could create a preferred radial polarization of the magnetic field. With an adaptive mesh refinement MHD code (AMRVAC), we simulate the evolution of SNRs with three different configurati...

  18. Atmospheric secondary charged cosmic radiation at a place of 11.5 GV geomagnetic cut-off

    Science.gov (United States)

    Azcarate, I. N.

    2002-04-01

    An experiment performed with a balloon-borne plastic scintillator is described. The detector system was transported by a stratospheric balloon, that was launched from Reconquista, province of Santa Fe, Argentina, on 24 February 1992. The geomagnetic cut-off of the site was 11.5 GV. The energy-loss spectra of both the atmospheric gamma radiation ( for E^γ>= 4.15 MeV) and the charged component of the secondary cosmic radiation were alternatively measured at different altitudes, during the ascent of the balloon, and at ceiling altitude. The author analyzed the atmospheric gamma-ray spectrum in a previous paper ( Azcárate, 2000). It was necessary to perform the computation of the response of the detector to the charged radiation in order to explain , at least qualitatively, the energy-loss spectrum in the detector produced by this type of radiation. It is argued that at ceiling altitude the observed feature in the spectrum is produced mainly by relativistic muons falling horizontally upon the detector. The growth curve for the counting rate below this feature and the intensity of relativistic μ-mesons were also obtained. References : Azcárate, I.N., Revista Mexicana de Astronomía y Astrofísica, 36, 81, 2000.

  19. Influence of cosmic radiation on aerosol and cloud formation over short time periods

    DEFF Research Database (Denmark)

    Bondo, Torsten

    This thesis describes a study of Forbush decrease events. These are rapid decreases in the cosmic ray intensity in the Earth’s atmosphere, which are caused by a temporary increased magnetic shielding at Earth due to solar eruptions. The aim is to investigate how these transient ionization phenomena...... for cosmic rays. A list of the ionization change in the troposphere of the strongest Forbush decreases as compared to the ionization change over the solar cycle is calculated and indicates that only a few events induce ionization changes comparable to the solar cycle. Studies of recently available high...... gas concentration on aerosol and cloud optical properties over short time. The model is used to examine experimental efforts at DTU Space on the role of ions in nucleation, as well as it is used to investigate observational data on Forbush decreases in aerosols. The model confirms the existence...

  20. Measuring the chemical composition of cosmic rays at about 10 to the 13th - 10 to the 15th eV by utilizing the solar and geomagnetic fields

    Science.gov (United States)

    Heintze, J.; Lennert, P.; Polenz, S.; Schmidt, B.; Spitzer, J.

    1989-01-01

    According to a proposal of Lloyd-Evans (1985), the average charge of particles in the cosmic radiation near 100 TeV can be determined by observing the effect of the solar magnetic field on the sun's shadow in the angular distribution of energetic primary cosmic-ray particles. This suggestion is shown to be realizable with a new type of EAS array proposed for the purpose of high-energy gamma-ray astronomy. The same measurement provides information on the integrated strength of the solar magnetic field. As the array will be sensitive and provide good angular resolution down to a few TeV, more detailed results on the primary composition near 10 TeV can be obtained by investigating the shape of the shadow of the moon as affected by the geomagnetic field.

  1. Graphite/Ultra-High Modulus Polyethylene Hybrid Fiber Composites with Epoxy and Polyethylene Matrices for Cosmic Radiation Shielding

    Science.gov (United States)

    2003-01-01

    One of the most significant technical challenges in long-duration space missions is that of protecting the crew from harmful radiation. Protection against such radiation on a manned Mars mission will be of vital importance both during transit and while on the surface of the planet. The development of multifunctional materials that serve as integral structural members of the space vehicle and provide the necessary radiation shielding for the crew would be both mission enabling and cost effective. Additionally, combining shielding and structure could reduce total vehicle mass. Hybrid laminated composite materials having both ultramodulus polyethylene (PE) and graphite fibers in epoxy and PE matrices could meet such mission requirements. PE fibers have excellent physical properties, including the highest specific strength of any known fiber. Moreover, the high hydrogen (H) content of polyethylene makes the material an excellent shielding material for cosmic radiation. When such materials are incorporated into an epoxy or PE matrix a very effective shielding material is expected. Boron (B) may be added to the matrix resin or used as a coating to further increase the shielding effectiveness due to B s ability to slow thermal neutrons. These materials may also serve as micrometeorites shields due to PE s high impact energy absorption properties. It should be noted that such materials can be fabricated by existing equipment and methods. It is the objective of this work therefore to: (a) perform preliminary analysis of the radiation transport within these materials; (b) fabricate panels for mechanical property testing before and after radiation exposure. Preliminary determination on the effectiveness of the combinations of material components on both shielding and structural efficiency will be made.

  2. Graphite/Ultra-High Modulus Polyethylene Hybrid Fiber Composites with Epoxy and Polyethylene Matrices for Cosmic Radiation Shielding

    Science.gov (United States)

    2003-01-01

    One of the most significant technical challenges in long-duration space missions is that of protecting the crew from harmful radiation. Protection against such radiation on a manned Mars mission will be of vital importance both during transit and while on the surface of the planet. The development of multifunctional materials that serve as integral structural members of the space vehicle and provide the necessary radiation shielding for the crew would be both mission enabling and cost effective. Additionally, combining shielding and structure could reduce total vehicle mass. Hybrid laminated composite materials having both ultramodulus polyethylene (PE) and graphite fibers in epoxy and PE matrices could meet such mission requirements. PE fibers have excellent physical properties, including the highest specific strength of any known fiber. Moreover, the high hydrogen (H) content of polyethylene makes the material an excellent shielding material for cosmic radiation. When such materials are incorporated into an epoxy or PE matrix a very effective shielding material is expected. Boron (B) may be added to the matrix resin or used as a coating to further increase the shielding effectiveness due to B s ability to slow thermal neutrons. These materials may also serve as micrometeorites shields due to PE s high impact energy absorption properties. It should be noted that such materials can be fabricated by existing equipment and methods. It is the objective of this work therefore to: (a) perform preliminary analysis of the radiation transport within these materials; (b) fabricate panels for mechanical property testing before and after radiation exposure. Preliminary determination on the effectiveness of the combinations of material components on both shielding and structural efficiency will be made.

  3. The Cosmic Infrared Background Experiment (CIBER): The Wide-field Imagers

    Science.gov (United States)

    Bock, J.; Sullivan, I.; Arai, T.; Battle, J.; Cooray, A.; Hristov, V.; Keating, B.; Kim, M. G.; Lam, A. C.; Lee, D. H.; Levenson, L. R.; Mason, P.; Matsumoto, T.; Matsuura, S.; Mitchell-Wynne, K.; Nam, U. W.; Renbarger, T.; Smidt, J.; Suzuki, K.; Tsumura, K.; Wada, T.; Zemcov, M.

    2013-08-01

    We have developed and characterized an imaging instrument to measure the spatial properties of the diffuse near-infrared extragalactic background light (EBL) in a search for fluctuations from z > 6 galaxies during the epoch of reionization. The instrument is part of the Cosmic Infrared Background Experiment (CIBER), designed to observe the EBL above Earth's atmosphere during a suborbital sounding rocket flight. The imaging instrument incorporates a 2° × 2° field of view to measure fluctuations over the predicted peak of the spatial power spectrum at 10 arcmin, and 7'' × 7'' pixels, to remove lower redshift galaxies to a depth sufficient to reduce the low-redshift galaxy clustering foreground below instrumental sensitivity. The imaging instrument employs two cameras with Δλ/λ ~ 0.5 bandpasses centered at 1.1 μm and 1.6 μm to spectrally discriminate reionization extragalactic background fluctuations from local foreground fluctuations. CIBER operates at wavelengths where the electromagnetic spectrum of the reionization extragalactic background is thought to peak, and complements fluctuation measurements by AKARI and Spitzer at longer wavelengths. We have characterized the instrument in the laboratory, including measurements of the sensitivity, flat-field response, stray light performance, and noise properties. Several modifications were made to the instrument following a first flight in 2009 February. The instrument performed to specifications in three subsequent flights, and the scientific data are now being analyzed.

  4. Constraints on primordial magnetic fields from the optical depth of the cosmic microwave background

    CERN Document Server

    Kunze, Kerstin E

    2015-01-01

    Damping of magnetic fields via ambipolar diffusion and decay of magnetohydrodynamical (MHD) turbulence in the post decoupling era heats the intergalactic medium (IGM). Collisional ionization weakly ionizes the IGM, producing an optical depth to scattering of the cosmic microwave background (CMB). The optical depth generated at $z\\gg 10$ does not affect the "reionization bump" of the CMB polarization power spectrum at low multipoles, but affects the temperature and polarization power spectra at high multipoles. Using the Planck 2013 temperature and lensing data together with the WMAP 9-year polarization data, we constrain the present-day field strength, $B_0$, smoothed over the damping length at the decoupling epoch as a function of the spectral index, $n_B$. We find the 95% upper bounds of $B_0<0.56$, 0.31, and 0.14 nG for $n_B=-2.9$, $-2.5$, and $-1.5$, respectively. For these spectral indices, the optical depth is dominated by dissipation of the decaying MHD turbulence that occurs shortly after the decou...

  5. Identification of positrons and electrons in the cosmic radiation with the electromagnetic calorimeter ECAL for the AMS-02 experiment

    CERN Document Server

    AUTHOR|(CDS)2080883

    2011-07-19

    In May 2011 AMS-02 detector has been successfully installed on the International Space Station (ISS), where it will take data on cosmic radiation from 1 to 1000 GeV for at least 10 years. Among all scientific objectives of the experiment, one of the most important is the search for Dark Matter (DM), which constitutes 80% of the Universe matter, but its nature is still unknown. A DM signal can be identified by studying the combined fluxes of positrons, photons, antiprotons and antideuterium. Thanks to its high acceptance and its performances, AMS-02 detector can extend primary cosmic ray physics search to a new energy range with high accuracy. A key role for these measurements, in particular for the electromagnetic channels, is played by ECAL calorimeter. This subdetector has been developed to measure e− and e+ energy with an accuracy of few %. Thanks to its 3D shower reconstruction imaging capabilities, it also has a high separation power between electromagnetic and hadronic showers (e/p rejection), essent...

  6. Self-constructed detectors for environmental radiation sources. Instruments for detecting and measuring electric and magnetic fields as well as radioactive radiation; Selbstgebaute Detektoren fuer Strahlenquellen in der Umwelt. Pruef- und Messgeraete fuer elektrische und magnetische Felder sowie radioaktive Strahlung

    Energy Technology Data Exchange (ETDEWEB)

    Lay, Peter

    2011-07-01

    The book presents experiments for detecting and measuring radiation sources. This includes detectors for electric and magnetic fields, radioactive radiation and even cosmic radiation, all of which can be detected by simple (electronic) circuits. Apart from the practical experiments, also basic physical knowledge is provided. The book comprises the following chapters: 1. Introduction; 2. Electrostatic fields in the environment; 3. Magnetostatic fields; 4. Electrodynamic fields; 5. Magnetodynamic fields; 6. Electromagnetic radiation in the environment; 7. Radioactive radiation in the environment; 8. Cosmic radiation; 9. PC interface; 10. Professional radiation measurement; 11. Risk potential. [German] In diesem Buch werden Experimente vorgestellt, mit denen man die verschiedenen Strahlenquellen nachweisen und messtechnisch erfassen kann. Darunter zaehlen Detektoren zum Nachweis elektrischer und magnetischer Felder, radioaktiver Strahlung und sogar von Strahlen aus dem Weltall. Mit einfachen (elektronischen) Schaltungen werden diese Gefahrenquellen aufgespuert. Neben vielen praxiserprobten Experimenten wird auch das physikalische Grundwissen vermittelt. Das Buch ist in folgende Kapitel aufgeteilt: 1. Einfuehrung; 2. Elektrostatische Felder in der Umwelt; 3. Magnetostatische Felder; 4. Elektrodynamische Felder; 5. Magentodynamische Felder; 6. Elektromagnetische Strahlen in der Umwelt; 7. Radioaktive Strahlen in der Umwelt; 8. Strahlen aus dem Weltall; 9. PC-Schnittstelle; 10. Professionelle Strahlenmessung; 11. Gefahrenpotenzial.

  7. Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy

    NARCIS (Netherlands)

    Aab, A.; Abreu, P.; Aglietta, M.; Ahn, E. J.; Al Samarai, I.; Albuquerque, I. F. M.; Allekotte, I.; Allison, P.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muniz, J.; Batista, R. Alves; Ambrosio, M.; Aminaei, A.; Anastasi, G. A.; Anchordoqui, L.; Andringa, S.; Aramo, C.; Arqueros, F.; Arsene, N.; Asorey, H.; Assis, P.; Aublin, J.; Avila, G.; Awal, N.; Badescu, A. M.; Baus, C.; Beatty, J. J.; Becker, K. H.; Bellido, J. A.; Berat, C.; Bertaina, M. E.; Bertou, X.; Biermann, P. L.; Billoir, P.; Blaess, S. G.; Blanco, A.; Blanco, M.; Blazek, J.; Bleve, C.; Bluemer, H.; Bohacova, M.; Boncioli, D.; Bonifazi, C.; Borodai, N.; Brack, J.; Brancus, I.; Bretz, T.; Bridgeman, A.; Brogueira, P.; Buchholz, P.; Bueno, A.; Buitink, S.; Buscemi, M.; Caballero-Mora, K. S.; Caccianiga, B.; Caccianiga, L.; Candusso, M.; Caramete, L.; Caruso, R.; Castellina, A.; Cataldi, G.; Cazon, L.; Cester, R.; Chavez, A. G.; Chiavassa, A.; Chinellato, J. A.; Chudoba, J.; Cilmo, M.; Clay, R. W.; Cocciolo, G.; Colalillo, R.; Coleman, A.; Collica, L.; Coluccia, M. R.; Conceicao, R.; Contreras, F.; Cooper, M. J.; Cordier, A.; Coutu, S.; Covault, C. E.; Cronin, J.; Dallier, R.; Daniel, B.; Dasso, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; de Jong, S. J.; De Mauro, G.; de Mello Neto, J. R. T.; De Mitri, I.; de Oliveira, J.; de Souza, V.; del Peral, L.; Deligny, O.; Dhital, N.; Di Giulio, C.; Di Matteo, A.; Diaz, J. C.; Diaz Castro, M. L.; Diogo, F.; Dobrigkeit, C.; Docters, W.; D'Olivo, J. C.; Dorofeev, A.; Hasankiadeh, Q. Dorosti; dos Anjos, R. C.; Dova, M. T.; Ebr, J.; Engel, R.; Erdmann, M.; Erfani, M.; Escobar, C. O.; Espadanal, J.; Etchegoyen, A.; Falcke, H.; Fang, K.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Ferguson, A. P.; Fick, B.; Figueira, J. M.; Filevich, A.; Filipcic, A.; Fratu, O.; Freire, M. M.; Fujii, T.; Garcia, B.; Garcia-Gamez, D.; Garcia-Pinto, D.; Gate, F.; Gemmeke, H.; Gherghel-Lascu, A.; Ghia, P. L.; Giaccari, U.; Giammarchi, M.; Giller, M.; Glas, D.; Glaser, C.; Glass, H.; Golup, G.; Gomez Berisso, M.; Gomez Vitale, P. F.; Gonzalez, N.; Gookin, B.; Gordon, J.; Gorgi, A.; Gorham, P.; Gouffon, P.; Griffith, N.; Grillo, A. F.; Grubb, T. D.; Guarino, F.; Guedes, G. P.; Hampel, M. R.; Hansen, P.; Harari, D.; Harrison, T. A.; Hartmann, S.; Harton, J. L.; Haungs, A.; Hebbeker, T.; Heck, D.; Heimann, P.; Herve, A. E.; Hill, G. C.; Hojvat, C.; Hollon, N.; Holt, E.; Homola, P.; Horandel, J. R.; Horvath, P.; Hrabovsky, M.; Huber, D.; Huege, T.; Insolia, A.; Isar, P. G.; Jandt, I.; Jansen, S.; Jarne, C.; Johnsen, J. A.; Josebachuili, M.; Kaeaepae, A.; Kambeitz, O.; Kampert, K. H.; Kasper, P.; Katkov, I.; Keilhauer, B.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Krause, R.; Krohm, N.; Kuempel, D.; Mezek, G. Kukec; Kunka, N.; Awad, A. W. Kuotb; LaHurd, D.; Latronico, L.; Lauer, R.; Lauscher, M.; Lautridou, P.; Le Coz, S.; Lebrun, D.; Lebrun, P.; Leigui de Oliveira, M. A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; Link, K.; Lopes, L.; Lopez, R.; Lopez Casado, A.; Louedec, K.; Lucero, A.; Malacari, M.; Mallamaci, M.; Maller, J.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Marin, V.; Maris, I. C.; Marsella, G.; Martello, D.; Martinez, H.; Martinez Bravo, O.; Martraire, D.; Masias Meza, J. J.; Mathes, H. J.; Mathys, S.; Matthews, J.; Matthews, J. A. J.; Matthiae, G.; Maurizio, D.; Mayotte, E.; Mazur, P. O.; Medina, C.; Medina-Tanco, G.; Meissner, R.; Mello, V. B. B.; Melo, D.; Menshikov, A.; Messina, S.; Micheletti, M. I.; Middendorf, L.; Minaya, I. A.; Miramonti, L.; Mitrica, B.; Molina-Bueno, L.; Mollerach, S.; Montanet, F.; Morello, C.; Mostafa, M.; Moura, C. A.; Muller, M. A.; Mueller, G.; Mueller, S.; Navas, S.; Necesal, P.; Nellen, L.; Nelles, A.; Neuser, J.; Nguyen, P. H.; Niculescu-Oglinzanu, M.; Niechciol, M.; Niemietz, L.; Niggemann, T.; Nitz, D.; Nosek, D.; Novotny, V.; Nozka, L.; Nunez, L. A.; Ochilo, L.; Oikonomou, F.; Olinto, A.; Pacheco, N.; Pakk Selmi-Dei, D.; Palatka, M.; Pallotta, J.; Papenbreer, P.; Parente, G.; Parra, A.; Paul, T.; Pech, M.; Pekala, J.; Pelayo, R.; Pepe, I. M.; Perrone, L.; Petermann, E.; Peters, C.; Petrera, S.; Petrov, Y.; Phuntsok, J.; Piegaia, R.; Pierog, T.; Pieroni, P.; Pimenta, M.; Pirronello, V.; Platino, M.; Plum, M.; Porcelli, A.; Porowski, C.; Prado, R. R.; Privitera, P.; Prouza, M.; Quel, E. J.; Querchfeld, S.; Quinn, S.; Rautenberg, J.; Ravel, O.; Ravignani, D.; Reinert, D.; Revenu, B.; Ridky, J.; Risse, M.; Ristori, P.; Rizi, V.; Rodrigues de Carvalho, W.; Rodriguez Rojo, J.; Rodriguez-Frias, M. D.; Rogozin, D.; Rosado, J.; Roth, M.; Roulet, E.; Rovero, A. C.; Saffi, S. J.; Saftoiu, A.; Salazar, H.; Saleh, A.; Greus, F. Salesa; Salina, G.; Sanabria Gomez, J. D.; Sanchez, F.; Sanchez-Lucas, P.; Santos, E.; Santos, E. M.; Sarazin, F.; Sarkar, B.; Sarmento, R.; Sarmiento-Cano, C.; Sato, R.; Scarso, C.; Schauer, M.; Scherini, V.; Schieler, H.; Schmidt, D.; Scholten, O.; Schoorlemmer, H.; Schovanek, P.; Schroeder, F. G.; Schulz, A.; Schulz, J.; Schumacher, J.; Sciutto, S. J.; Segreto, A.; Settimo, M.; Shadkam, A.; Shellard, R. C.; Sigl, G.; Sima, O.; Smialkowski, A.; Smida, R.; Snow, G. R.; Sommers, P.; Sonntag, S.; Sorokin, J.; Squartini, R.; Srivastava, Y. N.; Stanca, D.; Stanic, S.; Stapleton, J.; Stasielak, J.; Stephan, M.; Stutz, A.; Suarez, F.; Suarez Duran, M.; Suomijarvi, T.; Supanitsky, A. D.; Sutherland, M. S.; Swain, J.; Szadkowski, Z.; Taborda, O. A.; Tapia, A.; Tepe, A.; Theodoro, V. M.; Timmermans, C.; Todero Peixoto, C. J.; Toma, G.; Tomankova, L.; Tome, B.; Tonachini, A.; Torralba Elipe, G.; Torres Machado, D.; Travnicek, P.; Trini, M.; Ulrich, R.; Unger, M.; Urban, M.; Valdes Galicia, J. F.; Valino, I.; Valore, L.; van Aar, G.; van Bodegom, P.; van den Berg, A. M.; van Velzen, S.; van Vliet, A.; Varela, E.; Vargas Cardenas, B.; Varner, G.; Vasquez, R.; Vazquez, J. R.; Vazquez, R. A.; Veberic, D.; Verzi, V.; Vicha, J.; Videla, M.; Villasenor, L.; Vlcek, B.; Vorobiov, S.; Wahlberg, H.; Wainberg, O.; Walz, D.; Watson, A. A.; Weber, M.; Weidenhaupt, K.; Weindl, A.; Welling, C.; Werner, F.; Widom, A.; Wiencke, L.; Wilczynski, H.; Winchen, T.; Wittkowski, D.; Wundheiler, B.; Wykes, S.; Yang, L.; Yapici, T.; Yushkov, A.; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zepeda, A.; Zimmermann, B.; Ziolkowski, M.; Zuccarello, F.

    2016-01-01

    We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8 +/- 0.7 (stat) +/- 6.7 (syst) MeV for cosmic rays with an energy o

  8. Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy

    NARCIS (Netherlands)

    Aab, A.; Abreu, P.; Aglietta, M.; Ahn, E. J.; Al Samarai, I.; Albuquerque, I.F.M.; Allekotte, I.; Buitink, S.; Docters, W.; Dorosti Hasankiadeh, Q.; Messina, S.; Scholten, O.; van den Berg, A.M.

    2016-01-01

    We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8 +/- 0.7 (stat) +/- 6.7 (syst) MeV for cosmic rays with an energy o

  9. Cosmic radiation dosimetry onboard aircrafts at the brazilian airspace; Dosimetria da radiacao cosmica no interior de aeronaves no espaco aereo brasileiro

    Energy Technology Data Exchange (ETDEWEB)

    Federico, Claudio Antonio

    2011-07-01

    The objective of this work is the establishment of a dosimetric system for the aircrew in the domestic territory. A technique to perform measurements of ambient dose equivalent in aircrafts was developed. An active detector was evaluated for onboard aircraft use, testing its adequacy to this specific type of measurement as well as its susceptibility to the magnetic and electromagnetic interferences. The equipment was calibrated in standard radiation beams and in a special field of the European Laboratory CERN, that reproduces with great proximity the real spectrum in aircraft flight altitudes; it was also tested in several flights, in an Brazilian Air Force's aircraft. The results were evaluated and compared with those obtained from several computational programs for cosmic radiation estimates, with respect to its adequacy for use in the South American region. The program CARI-6 was selected to evaluate the estimated averaged effective doses for the aircrew who operate in this region. A statistical distribution of aircrew effective doses in South America and Caribe was made, and the results show that a great part of this aircrew members are subjected to annual effective doses that exceed the dose limits for the members of the public. Additionally, a preliminary passive dosemeter, based in thermoluminescent detectors, was proposed; international collaborations with United Kingdom and Italy were established for joint measurements of the ambient equivalent doses in aircrafts. (author)

  10. Strong magnetic fields and SGRs/AXPs as white dwarf pulsar: a source of ultra-high energy cosmic rays

    Science.gov (United States)

    Lobato, Ronaldo V.; Malheiro, M.

    2016-04-01

    The origin of highest energy cosmic rays still remains a mystery in Astrophysics. In this work we consider the Soft Gamma Repeaters (SGRs) and Anomalous X-ray Pulsars (AXPs) as possible sources of ultra-high cosmic rays. These stars described as white dwarfs pulsars can achieved large electric potential differences in their surface and accelerate particles up to Lorentz factors γ ∼ 1010. Pulsars offer favorable sites for the injection of electrons and heavy nuclei, and accelerate them to ultrahigh energies. Once accelerated in the pulsar this particles can escape from the magnetosphere and produce the radiation observed. Here, we discuss the possibility of SGRs/AXPs as white dwarf pulsars to be possible sources of ultra-high energetic photons with E ∼ 1021eV.

  11. Radiation Fields in the Vicinity of Compact Accelerator Neutron Generators

    Energy Technology Data Exchange (ETDEWEB)

    David L. Chichester; Brandon W. Blackburn; Augustine J. Caffrey

    2006-10-01

    Intense pulsed radiation fields emitted from sealed tube neutron generators provide a challenge for modern health physics survey instrumentation. The spectral sensitivity of these survey instruments requires calibration under realistic field conditions while the pulsed emission characteristics of neutron generators can vary from conditions of steady-state operation. As a general guide for assessing radiological conditions around neutron generators, experiments and modeling simulations have been performed to assess radiation fields near DD and DT neutron generators. The presence of other materials and material configurations can also have important effects on the radiation dose fields around compact accelerator neutron generators.

  12. Reconstructing the Cosmic Velocity and Tidal Fields with Galaxy Groups Selected from the Sloan Digital Sky Survey

    CERN Document Server

    Wang, Huiyuan; Yang, Xiaohu; Bosch, Frank C van den

    2011-01-01

    [abridge]Cosmic velocity and tidal fields are important for the understanding of the cosmic web and the environments of galaxies, and can also be used to constrain cosmology. In this paper, we reconstruct these two fields in SDSS volume from dark matter halos represented by galaxy groups. Detailed mock catalogues are used to test the reliability of our method against uncertainties arising from redshift distortions, survey boundaries, and false identifications of groups by our group finder. We find that both the velocity and tidal fields, smoothed on a scale of ~2Mpc/h, can be reliably reconstructed in the inner region (~66%) of the survey volume. The reconstructed tidal field is used to split the cosmic web into clusters, filaments, sheets, and voids, depending on the sign of the eigenvalues of tidal tensor. The reconstructed velocity field nicely shows how the flows are diverging from the centers of voids, and converging onto clusters, while sheets and filaments have flows that are convergent along one and t...

  13. Cosmic radiation and airline pilots. Exposure patterns of Norwegian SAS-pilots 1960 to 1994. Revised Version

    Energy Technology Data Exchange (ETDEWEB)

    Tveten, U

    1999-02-01

    The present report is a revised version of an earlier report (IFE/KR/E-96/008). The revision has been carried out since a completely new version of the computational tool has recently been released. All calculations have been redone. The work which is presented in this report is part of a Norwegian epidemiological project, carried out in cooperation between Institute for Energy Technology (IFE), the Norwegian Cancer Registry (NCR) and the Norwegian Radiation Protection Authority (NRPA). Originating from the Norwegian project, a number of similar projects have been started in a number of European countries. The present report lays the ground for estimation of individual exposure histories to cosmic radiation of pilots employed by the the Scandinavian Airlines System (SAS). The result presented in this report (radiation dose rates for the different types of aircraft in the different years) were calculated with the most recent computer program for this purpose, the CARI-5E from the United States Civil Aviation Authority. The other major sources of information used as basis for this work is the collection of old SAS time tables found the the SAS Museum at Fornebu Airport in Oslo, and information provided by members of the Pilots Association in Norway.

  14. Radiological risk assessment of cosmic radiation at aviation altitudes (a trip from Houston Intercontinental Airport to Lagos International Airport

    Directory of Open Access Journals (Sweden)

    Paschal Ikenna Enyinna

    2016-01-01

    Full Text Available Radiological risk parameters associated with aircrew members traveling from Houston Intercontinental Airport to Lagos International Airport have been computed using computer software called EPCARD (version 3.2. The mean annual effective dose of radiation was computed to be 2.94 mSv/year. This result is above the standard permissible limit of 1 mSv/year set for the public and pregnant aircrew members but below the limit set for occupationally exposed workers. The Risk of cancer mortality and excess career time cancer risk computed ranged from 3.5 × 10−5 to 24.5 × 10−5 (with average of 14.7 × 10−5 and 7 × 10−4 to 49 × 10−4 (with average of 29.4 × 10−4 . Passengers and aircrew members should be aware of the extra cosmic radiation doses taken in during flights. All aircraft operators should monitor radiation doses incurred during aviation trips.

  15. The small contribution of molecular Bremsstrahlung radiation to the air-fluorescence yield of cosmic ray shower particles

    Science.gov (United States)

    Al Samarai, Imen; Deligny, Olivier; Rosado, Jaime

    2016-10-01

    A small contribution of molecular Bremsstrahlung radiation to the air-fluorescence yield in the UV range is estimated based on an approach previously developed in the framework of the radio-detection of showers in the gigahertz frequency range. First, this approach is shown to provide an estimate of the main contribution of the fluorescence yield due to the de-excitation of the C 3Πu electronic level of nitrogen molecules to the B 3Πg one amounting to Y[ 337 ] =(6.05 ± 1.50) MeV-1 at 800 hPa pressure and 293 K temperature conditions, which compares well to previous dedicated works and to experimental results. Then, under the same pressure and temperature conditions, the fluorescence yield induced by molecular Bremsstrahlung radiation is found to be Y[330-400]MBR = 0.10 MeV-1 in the wavelength range of interest for the air-fluorescence detectors used to detect extensive air showers induced in the atmosphere by ultra-high energy cosmic rays. This means that out of ≃175 photons with wavelength between 330 and 400 nm detected by fluorescence detectors, one of them has been produced by molecular Bremsstrahlung radiation. Although small, this contribution is not negligible in regards to the total budget of systematic uncertainties when considering the absolute energy scale of fluorescence detectors.

  16. Detecting dark matter in the Milky Way with cosmic and gamma radiation

    Science.gov (United States)

    Carlson, Eric C.

    Over the last decade, experiments in high-energy astroparticle physics have reached unprecedented precision and sensitivity which span the electromagnetic and cosmic-ray spectra. These advances have opened a new window onto the universe for which little was previously known. Such dramatic increases in sensitivity lead naturally to claims of excess emission, which call for either revised astrophysical models or the existence of exotic new sources such as particle dark matter. Here we stand firmly with Occam, sharpening his razor by (i) developing new techniques for discriminating astrophysical signatures from those of dark matter, and (ii) by developing detailed foreground models which can explain excess signals and shed light on the underlying astrophysical processes at hand. We concentrate most directly on observations of Galactic gamma and cosmic rays, factoring the discussion into three related parts which each contain significant advancements from our cumulative works. In Part I we introduce concepts which are fundamental to the Indirect Detection of particle dark matter, including motivations, targets, experiments, production of Standard Model particles, and a variety of statistical techniques. In Part II we introduce basic and advanced modelling techniques for propagation of cosmic-rays through the Galaxy and describe astrophysical gamma-ray production, as well as presenting state-of-the-art propagation models of the Milky Way.Finally, in Part III, we employ these models and techniques in order to study several indirect detection signals, including the Fermi GeV excess at the Galactic center, the Fermi 135 GeV line, the 3.5 keV line, and the WMAP-Planck haze.

  17. Probing physics at extreme energies with cosmic ultra-high energy radiation

    Indian Academy of Sciences (India)

    Günter Sigl

    2003-02-01

    The highest energy cosmic rays observed possess macroscopic energies and their origin is likely to be associated with the most energetic processes in the universe. Their existence triggered a flurry of theoretical explanations ranging from conventional shock acceleration to particle physics beyond the standard model (SM) and processes taking place at the earliest moments of our universe. Furthermore, many new experimental activities promise a strong increase of statistics at the highest energies and a combination with -ray and neutrino astrophysics will put strong constraints on these theoretical models. We give an overview over this quickly evolving research field with focus on testing new particle physics.

  18. Deficiencies of active electronic radiation protection dosimeters in pulsed fields.

    Science.gov (United States)

    Ankerhold, U; Hupe, O; Ambrosi, P

    2009-07-01

    Nowadays nearly all radiation fields used for X-ray diagnostics are pulsed. These fields are characterised by a high dose rate during the pulse and a short pulse duration in the range of a few milliseconds. The use of active electronic dosimeters has increased in the past few years, but these types of dosimeters might possibly not measure reliably in pulsed radiation fields. Not only personal dosimeters but also area dosimeters that are used mainly for dose rate measurements are concerned. These cannot be substituted by using passive dosimeter types. The characteristics of active electronic dosimeters determined in a continuous radiation field cannot be transferred to those in pulsed fields. Some provisional measurements with typical electronic dosimeters in pulsed radiation fields are presented to reveal this basic problem.

  19. Nonbaryonic dark matter and scalar field coupled with a transversal interaction plus decoupled radiation

    CERN Document Server

    Chimento, Luis P

    2013-01-01

    We analyze a universe filled with interacting dark matter, a scalar field accommodated as dark radiation along with dark energy plus a decoupled radiation term within the framework of spatially flat Friedmann-Robertson-Walker (FRW) spacetime. We work in a three-dimensional internal space spanned by the interaction vector and use a transversal interaction $\\mathbf{Q_t}$ for solving the source equation in order to find all the interacting component energy densities. We asymptotically reconstruct the scalar field and potential from an early radiation era to the late dominate dark energy one, passing through an intermediate epoch dominated by dark matter. We apply the $\\chi^{2}$ method to the updated observational Hubble data for constraining the cosmic parameters, contrast with the Union 2 sample of supernovae, and analyze the amount of dark energy in the radiation era. It turns out that our model fulfills the severe bound of $\\Omega_{\\rm \\phi}(z\\simeq 1100)<0.018$ at $2\\sigma$ level, is consistent with the r...

  20. Radiation reaction in quantum field theory

    Science.gov (United States)

    Higuchi, Atsushi

    2002-11-01

    We investigate radiation-reaction effects for a charged scalar particle accelerated by an external potential realized as a space-dependent mass term in quantum electrodynamics. In particular, we calculate the position shift of the final-state wave packet of the charged particle due to radiation at lowest order in the fine structure constant α and in the small ħ approximation. We show that it disagrees with the result obtained using the Lorentz-Dirac formula for the radiation-reaction force, and that it agrees with the classical theory if one assumes that the particle loses its energy to radiation at each moment of time according to the Larmor formula in the static frame of the potential. However, the discrepancy is much smaller than the Compton wavelength of the particle. We also point out that the electromagnetic correction to the potential has no classical limit.

  1. Resistance of lichens to simulated galactic cosmic radiation: limits of survival capacity and biosignature detection

    Science.gov (United States)

    de la Torre Noetzel, Rosa; Miller, Ana Z.; Cubero, Beatriz; Raguse, Marina; Meessen, Joachim

    2016-04-01

    Space constitutes an extremely harmful environment for survival of terrestrial organisms. Amongst extremophiles on Earth, lichens are one of the most resistant organisms to harsh terrestrial environments, as well as some species of microorganisms, such as bacteria (Moeller et al., 2010), criptoendolithic cyanobacteria and lithic fungi (de los Ríos et al. 2004). To study the survival capacity of lichens to the harmful radiation environment of space, we have selected the lichen Circinaria gyrosa, an astrobiological model defined by its high capacity of resistance to space conditions (De la Torre et al. 2010) and to a simulated Mars environment (Sanchez et al., 2012). Samples were irradiated with four types of space-relevant ionizing radiation in the STARLIFE campaign: helium and iron ion doses (up to 2,000 Gy), X-ray doses (up to 5,000 Gy) and ultra-high γ-ray doses (from 6 to 113 kGy). Results on resistance of C. gyrosa to space-relevant ionizing radiation and its post-irradiation viability were obtained by: (i) chlorophyll a fluorescence of photosystem II (PS II); (ii) epifluorescence microscopy; (iii) confocal laser-scanning microscopy (CLSM), and (iv) field emission scanning electron microscopy (FESEM). Results of photosynthetic activity and epifluorescence showed no significant changes on the viability of C. gyrosa with increasing doses of helium and iron ions as well as X-rays. In contrast, γ-irradiation elicited significant dose-correlated effects as revealed by all applied techniques. Relevant is the presence of whewellite-like crystals, detected by FESEM on C. gyrosa thalli after high irradiation doses, which has been also identified in previous Mars simulation studies (Böttcher et al., 2014). These studies contribute to the better understanding of the adaptability of extremophile organisms to harsh environments, as well as to estimate the habitability of a planet's surface, like Mars; they will be important for planning experiments on the search of life

  2. Separation of radiation from two sources from their known radiated sum field

    DEFF Research Database (Denmark)

    Laitinen, Tommi; Pivnenko, Sergey

    2011-01-01

    This paper presents a technique for complete and exact separation of the radiated fields of two sources (at the same frequency) from the knowledge of their radiated sum field. The two sources can be arbitrary but it must be possible to enclose the sources inside their own non-intersecting minimum...

  3. Does Galactic Magnetic Field Disturb the Correlation of the Highest Energy Cosmic Rays with their Sources?

    CERN Document Server

    Takami, Hajime

    2009-01-01

    The propagation trajectories of the highest energy cosmic rays can be deflected by Galactic magnetic field (GMF) and expected correlation between their arrival directions and the positions of their sources can be disturbed. In order to explore whether the possible correlation is disturbed or not, we simulate the arrival distribution of the highest energy protons (HEPs) with energies above $6 \\times 10^{19}$ eV taking 4 different GMF models into account and investigate the cross-correlation between the protons and sources assumed in the simulation. We show that the error of cross-correlation function adopted in this study is sufficiently small by accumulating 200 events. We also find that the correlation is not disturbed largely in many cases after 200 events accumulation and positive signals of the correlation are significantly expected at angular scale of 3-5$^{\\circ}$. Only in the cases of the northern sky with axisymmetric spiral structures of GMF, the cross-correlation functions are consistent with no cor...

  4. Multiple quantum collapse of the inflaton field and its implications on the birth of cosmic structure

    Energy Technology Data Exchange (ETDEWEB)

    Leon, Gabriel [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Mexico DF 04510 (Mexico); De Unanue, Adolfo [C3 Centro de Ciencias de la Complejidad, Universidad Nacional Autonoma de Mexico, Torre de IngenierIa, Circuito Exterior S/N Ciudad Universitaria, Mexico DF 04510 (Mexico); Sudarsky, Daniel, E-mail: gabriel.leon@nucleares.unam.mx, E-mail: adolfo@nucleares.unam.mx, E-mail: sudarsky@nucleares.unam.mx [Instituto de AstronomIa y Fisica del Espacio (UBA-CONICET), Casilla de Correos 67, Sucursal 28, 1428 Buenos Aires (Argentina)

    2011-08-07

    The standard inflationary account for the origin of cosmic structure is, without a doubt, extremely successful. However, it is not fully satisfactory as has been argued in Perez et al (2006 Class. Quantum Grav. 23 2317). The central point is that, in the standard accounts, the inhomogeneity and anisotropy of our universe seem to emerge, unexplained, from an exactly homogeneous and isotropic initial state through processes that do not break those symmetries. The proposal made there to address this shortcoming calls for a dynamical and self-induced quantum collapse of the original homogeneous and isotropic state of the inflaton. In this paper, we consider the possibility of a multiplicity of collapses in each one of the modes of the quantum field. As we will see, the results are sensitive to a more detailed characterization of the collapse than those studied in the previous works, and in this regard two simple options will be studied. We find important constraints on the model, most remarkably on the number of possible collapses for each mode.

  5. Assessment of a relative contribution of terrestrial background radiation in the test field by using RADIAGEMTM 2000 portable survey meter

    Directory of Open Access Journals (Sweden)

    Avdić Senada

    2016-01-01

    Full Text Available This study is focused on the radiological investigation of terrestrial gamma radiation in the test field with soil samples from different minefields in the Federation of Bosnia and Herzegovina. Measurements of ambient dose equivalent rate, commonly referred to as “air dose rate”, in the test field located in the Tuzla Canton, were performed by RADIAGEMTM 2000 portable survey meter, based on energy-compensated Geiger-Muller counter. Its performances were tested in the laboratory conditions with gamma point sources. Since all the samples in the test field were exposed to the same cosmic radiation, there was a possibility to assess a relative contribution of terrestrial gamma radiation due to soil samples of different composition. One set of measurements in the test field was performed with RADIAGEMTM 2000, at a height of about one meter above the ground and basic statistical parameters indicated that there was no significant difference of terrestrial gamma radiation from different soil samples. The other set of measurements was carried out with the same device placed on the ground in the test field. Processing of experimental data on terrestrial gamma radiation has shown that it was possible to make a difference between relative contributions of terrestrial gamma radiation from individual soil samples. The results of investigation could be useful for multiple purposes of public interest.

  6. Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey -- UDS Field

    Science.gov (United States)

    Faber, Sandra

    2010-09-01

    The Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey {CANDELS}is designed to document the ?rst third of galactic evolution from z =8 to 1.5 via deep imaging of more than 250,000 galaxies with WFC3/IRand ACS. It will also find the first Type Ia SNe beyond z > 1.5 andestablish their accuracy as standard candles for cosmology. Fivepremier multi-wavelength sky regions are selected from the SpitzerExtragalactic Deep Survey {SEDS} to provide complementary IRAC imagingdata down to 26.5 AB mag, a unique resource for stellar masses at allredshifts. The use of ?ve widely separated ?elds mitigates cosmicvariance and yields statistically robust and complete samples ofgalaxies down to 10^9 solar masses out to z 8.The program merges two originally separate MCT proposals. The Faberprogram incorporates a ?Wide? imaging survey in three separate fieldsto 2 orbit depth over 0.2 sq. degrees, plus a ?Deep? imaging surveyto 12 orbit depth in the two GOODS regions over 0.04 sq. degrees.In combination with ultra-deep imaging from the Hubble Ultradeep Fieldprogram {GO 11563}, the result is a three-tiered strategy that ef?cientlysamples both bright/rare and faint/common extragalactic objects. TheFerguson program adds an extensive high-redshift Type Ia SNe search,plus ultraviolet "daytime" UVIS exposures in GOODS-N to exploit theCVZ opportunity in that field.This program, GO 12064, is part of the Wide mosaic survey, which has thefollowing field centers and sizes: Field ID RA{2000} Dec{2000} WFC3 Dim. PA on sky UDS 02 17 38 -05 12 02 4x11 270 COSMOS 10 00 31 +02 24 00 4x11 180 EGS 14 19 31 +52 54 10 3x15 41 Science highlights from the Wide program: * Underlying structural properties of galaxies as revealed by WFC3-IR images sensitive to older stars {beyond the 4000-A break} and less affected by dust than ACS. A key redshift is z 2, where star-formation peaks, QSOs are most abundant, and where restframe B-band is still accessible to WFC3. Sample questions include: - Structure in young

  7. Radiation and reflection acoustical fields of an annular phased array

    Institute of Scientific and Technical Information of China (English)

    LAI Puxiang; ZHANG Bixing; WANG Chenghao

    2007-01-01

    The characteristics of the radiation and reflection acoustical fields of an annular phased array are investigated. The effects of the element number, element radius, interelement spacing, centre frequency, focus position, and other parameters on the radiation acoustical field of the annular phased array is theoretically studied. In experiment, an annular transducer with 8 equal-area elements is designed and fabricated, and a series of experimental measurements are conducted. The radiation acoustical field and its reflection on a liquid-solid interface are theoretically and experimentally studied. The experimental result is in good agreement with the theoretical one.

  8. A method for establishing constraints on galactic magnetic field models using ultra high energy cosmic rays and results from the data of the Pierre Auger Observatory

    Science.gov (United States)

    Sutherland, Michael Stephen

    2010-12-01

    The Galactic magnetic field is poorly understood. Essentially the only reliable measurements of its properties are the local orientation and field strength. Its behavior at galactic scales is unknown. Historically, magnetic field measurements have been performed using radio astronomy techniques which are sensitive to certain regions of the Galaxy and rely upon models of the distribution of gas and dust within the disk. However, the deflection of trajectories of ultra high energy cosmic rays arriving from extragalactic sources depends only on the properties of the magnetic field. In this work, a method is developed for determining acceptable global models of the Galactic magnetic field by backtracking cosmic rays through the field model. This method constrains the parameter space of magnetic field models by comparing a test statistic between backtracked cosmic rays and isotropic expectations for assumed cosmic ray source and composition hypotheses. Constraints on Galactic magnetic field models are established using data from the southern site of the Pierre Auger Observatory under various source distribution and cosmic ray composition hypotheses. Field models possessing structure similar to the stellar spiral arms are found to be inconsistent with hypotheses of an iron cosmic ray composition and sources selected from catalogs tracing the local matter distribution in the universe. These field models are consistent with hypothesis combinations of proton composition and sources tracing the local matter distribution. In particular, strong constraints are found on the parameter space of bisymmetric magnetic field models scanned under hypotheses of proton composition and sources selected from the 2MRS-VS, Swift 39-month, and VCV catalogs. Assuming that the Galactic magnetic field is well-described by a bisymmetric model under these hypotheses, the magnetic field strength near the Sun is less than 3-4 muG and magnetic pitch angle is less than -8°. These results comprise

  9. THE COSMIC INFRARED BACKGROUND EXPERIMENT (CIBER): THE WIDE-FIELD IMAGERS

    Energy Technology Data Exchange (ETDEWEB)

    Bock, J.; Battle, J. [Jet Propulsion Laboratory (JPL), National Aeronautics and Space Administration (NASA), Pasadena, CA 91109 (United States); Sullivan, I. [Department of Physics, University of Washington, Seattle, WA 98195 (United States); Arai, T.; Matsumoto, T.; Matsuura, S.; Tsumura, K. [Department of Space Astronomy and Astrophysics, Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara, Kanagawa 252-5210 (Japan); Cooray, A.; Mitchell-Wynne, K.; Smidt, J. [Center for Cosmology, University of California, Irvine, CA 92697 (United States); Hristov, V.; Lam, A. C.; Levenson, L. R.; Mason, P. [Department of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Keating, B.; Renbarger, T. [Department of Physics, University of California, San Diego, San Diego, CA 92093 (United States); Kim, M. G. [Department of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of); Lee, D. H. [Institute of Astronomy and Astrophysics, Academia Sinica, National Taiwan University, Taipei 10617, Taiwan (China); Nam, U. W. [Korea Astronomy and Space Science Institute (KASI), Daejeon 305-348 (Korea, Republic of); Suzuki, K. [Instrument Development Group of Technical Center, Nagoya University, Nagoya, Aichi 464-8602 (Japan); and others

    2013-08-15

    We have developed and characterized an imaging instrument to measure the spatial properties of the diffuse near-infrared extragalactic background light (EBL) in a search for fluctuations from z > 6 galaxies during the epoch of reionization. The instrument is part of the Cosmic Infrared Background Experiment (CIBER), designed to observe the EBL above Earth's atmosphere during a suborbital sounding rocket flight. The imaging instrument incorporates a 2 Degree-Sign Multiplication-Sign 2 Degree-Sign field of view to measure fluctuations over the predicted peak of the spatial power spectrum at 10 arcmin, and 7'' Multiplication-Sign 7'' pixels, to remove lower redshift galaxies to a depth sufficient to reduce the low-redshift galaxy clustering foreground below instrumental sensitivity. The imaging instrument employs two cameras with {Delta}{lambda}/{lambda} {approx} 0.5 bandpasses centered at 1.1 {mu}m and 1.6 {mu}m to spectrally discriminate reionization extragalactic background fluctuations from local foreground fluctuations. CIBER operates at wavelengths where the electromagnetic spectrum of the reionization extragalactic background is thought to peak, and complements fluctuation measurements by AKARI and Spitzer at longer wavelengths. We have characterized the instrument in the laboratory, including measurements of the sensitivity, flat-field response, stray light performance, and noise properties. Several modifications were made to the instrument following a first flight in 2009 February. The instrument performed to specifications in three subsequent flights, and the scientific data are now being analyzed.

  10. Ralph A. Alpher, George Antonovich Gamow, and the Prediction of the Cosmic Microwave Background Radiation

    OpenAIRE

    2014-01-01

    The first prediction of the existence of "relict radiation" or radiation remaining from the "Big Bang" was made in 1948. This derived from the seminal dissertation work of Ralph A. Alpher. He was a doctoral student of George A. Gamow and developed several critical advances in cosmology in late 1946, 1947, and 1948. Alpher developed the ideas of "hot" big bang cosmology to a high degree of physical precision, and was the first to present the idea that radiation, not matter, predominated the ea...

  11. Isotropic blackbody cosmic microwave background radiation as evidence for a homogeneous universe.

    Science.gov (United States)

    Clifton, Timothy; Clarkson, Chris; Bull, Philip

    2012-08-03

    The question of whether the Universe is spatially homogeneous and isotropic on the largest scales is of fundamental importance to cosmology but has not yet been answered decisively. Surprisingly, neither an isotropic primary cosmic microwave background (CMB) nor combined observations of luminosity distances and galaxy number counts are sufficient to establish such a result. The inclusion of the Sunyaev-Zel'dovich effect in CMB observations, however, dramatically improves this situation. We show that even a solitary observer who sees an isotropic blackbody CMB can conclude that the Universe is homogeneous and isotropic in their causal past when the Sunyaev-Zel'dovich effect is present. Critically, however, the CMB must either be viewed for an extended period of time, or CMB photons that have scattered more than once must be detected. This result provides a theoretical underpinning for testing the cosmological principle with observations of the CMB alone.

  12. Improving the radiation hardness of graphene field effect transistors

    Science.gov (United States)

    Alexandrou, Konstantinos; Masurkar, Amrita; Edrees, Hassan; Wishart, James F.; Hao, Yufeng; Petrone, Nicholas; Hone, James; Kymissis, Ioannis

    2016-10-01

    Ionizing radiation poses a significant challenge to the operation and reliability of conventional silicon-based devices. Here, we report the effects of gamma radiation on graphene field-effect transistors (GFETs), along with a method to mitigate those effects by developing a radiation-hardened version of our back-gated GFETs. We demonstrate that activated atmospheric oxygen from the gamma ray interaction with air damages the semiconductor device, and damage to the substrate contributes additional threshold voltage instability. Our radiation-hardened devices, which have protection against these two effects, exhibit minimal performance degradation, improved stability, and significantly reduced hysteresis after prolonged gamma radiation exposure. We believe this work provides an insight into graphene's interactions with ionizing radiation that could enable future graphene-based electronic devices to be used for space, military, and other radiation-sensitive applications.

  13. High Energy Particle Acceleration And Turbulent Magnetic Field Amplification In Shell-type Supernova Remnants (cosmic Rays, Cas A)

    CERN Document Server

    Keohane, J W

    1998-01-01

    This thesis contains observational studies of shell-type supernova remnants (SNRs), primarily using the ROSAT and ASCA X-ray observatories. These results include: (1) evidence for turbulent magnetic field amplification in the young supernova remnant Cas A, (2) upper limits on the maximum energy which SNRs accelerate cosmic rays. (1) When inhomogeneous absorption is taken into account, the soft X- ray and radio morphologies of the young SNR, Cas A, are strikingly similar. We conclude from the slope of the X-ray/radio surface brightness correlation, that the density of gas (traced by the X-ray) is proportional to the square of the magnetic field (traced by the radio). This implies that Cas A's magnetic field is continuously being amplified on small scales, as would be expected in a turbulent plasma. (2) SNRs are known to accelerate cosmic rays to GeV range energies, and they are generally assumed to produce the majority of Galactic cosmic rays with energies below 1,000 TeV (the "knee"). We investigate X-ray syn...

  14. Effect of near-earth thunderstorms electric field on the intensity of ground cosmic ray positrons/electrons in Tibet

    Science.gov (United States)

    Zhou, X. X.; Wang, X. J.; Huang, D. H.; Jia, H. Y.

    2016-11-01

    Monte Carlo simulations are performed to study the correlation between the ground cosmic ray intensity and near-earth thunderstorms electric field at YBJ (located at YangBaJing, Tibet, China, 4300 m a. s. l.). The variations of the secondary cosmic ray intensity are found to be highly dependent on the strength and polarity of the electric field. In negative fields and in positive fields greater than 600 V/cm, the total number of ground comic ray positrons and electrons increases with increasing electric field strength. And these values increase more obviously when involving a shower with lower primary energy or a higher zenith angle. While in positive fields ranging from 0 to 600 V/cm, the total number of ground comic ray positrons and electrons declines and the amplitude is up to 3.1% for vertical showers. A decrease of intensity occurs in inclined showers within the range of 0-500 V/cm, which is accompanied by smaller amplitudes. In this paper, the intensity changes are analyzed, especially concerning those decreasing phenomena in positive electric fields. Our simulation results could be helpful in understanding the decreases observed in some ground-based experiments (such as the Carpet air shower array and ARGO-YBJ), and also be useful in understanding the acceleration mechanisms of secondary charged particles caused by an atmospheric electric field.

  15. Effects of cosmic radiation on devices and embedded systems in aircrafts

    Energy Technology Data Exchange (ETDEWEB)

    Prado, Adriane C.M.; Federico, Claudio A.; Pereira Junior, Evaldo C.F.; Goncalez, Odair L., E-mail: claudiofederico@ieav.cta.br, E-mail: odairlelisgoncalez@gmail.com, E-mail: adriane.acm@hotmail.com, E-mail: evaldocarlosjr@gmail.com [Instituto de Estudos Avancados (IEAV/DCTA), Sao Jose dos Campos, SP (Brazil)

    2013-07-01

    Modern avionics systems use new electronic technologies devices that, due to their high degree of sophistication and miniaturization, are more susceptible to the effects of ionizing radiation, particularly the effect called 'Single Event Effect' (SEE) produced by neutron. Studies regarding the effects of radiation on electronic systems for space applications, such as satellites and orbital stations, have already been in progress for several years. However, tolerance requirements and specific studies, focusing on testing dedicated to avionics, have caused concern and gained importance in the last decade as a result of the accidents attributed to SEE in aircraft. Due to the development of a higher ceiling, an increase in airflow and a greater autonomy of certain aircrafts, the problem regarding the control of ionizing radiation dose received by the pilots, the crew and sensitive equipment became important in the areas of occupational health, radiation protection and flight safety. This paper presents an overview of the effects of ionizing radiation on devices and embedded systems in aircrafts, identifying and classifying these effects in relation to their potential risks in each device class. The assessment of these effects in avionics is a very important and emerging issue nowadays, which is being discussed by groups of the international scientific community; however, in South America, groups working in this area are still unknown. Consequently, this work is a great contribution and significantly valuable to the area of aeronautical engineering and flight safety associated to the effects of radiation on electronic components embedded in aircraft. (author)

  16. Space life sciences: structure and dynamics of the global space radiation field at aircraft altitudes.

    Science.gov (United States)

    2003-01-01

    This issue is devoted to research papers on the radiation environment encountered by aircraft crew members and the flying public, both of which are exposed to a higher than average radiation dose. Two types of space radiation are considered: galactic cosmic radiation and solar activity. The papers include reviews on atmospheric ionization radiation, the factors controlling this radiation, the modeling of this radiation, and measurements made on board specific aircraft flights during solar minimum and solar maximum conditions, and during the major solar proton events that occurred in 1989 and 2001.

  17. The Small Contribution of Molecular Bremsstrahlung Radiation to the Air-Fluorescence Yield of Cosmic Ray Shower Particles

    CERN Document Server

    Samarai, I Al; Rosado, J

    2016-01-01

    A small contribution of molecular Bremsstrahlung radiation to the air-fluorescence yield in the UV range is estimated based on an approach previously developed in the framework of the radio-detection of showers in the gigahertz frequency range. First, this approach is shown to provide an estimate of the main contribution of the fluorescence yield due to the de-excitation of the C $^3\\Pi_{\\mathrm{u}}$ electronic level of nitrogen molecules to the B $^3\\Pi_{\\mathrm{g}}$ one amounting to $Y_{[337]}=(6.05\\pm 1.50)~$ MeV$^{-1}$ at 800 hPa pressure and 293 K temperature conditions, which compares well to previous dedicated works and to experimental results. Then, under the same pressure and temperature conditions, the fluorescence yield induced by molecular Bremsstrahlung radiation is found to be $Y_{[330-400]}^{\\mathrm{MBR}}=0.10~$ MeV$^{-1}$ in the wavelength range of interest for the air-fluorescence detectors used to detect extensive air showers induced in the atmosphere by ultra-high energy cosmic rays. This m...

  18. Study of magnetic field expansion using a plasma generator for space radiation active protection

    Institute of Scientific and Technical Information of China (English)

    JIA Xiang-Hong; JIA Shao-Xia; XU Feng; BAI Yan-Qiang; WAN Jun; LIU Hong-Tao; JIANG Rui

    2013-01-01

    There are many active protecting methods including Electrostatic Fields,Confined Magnetic Field,Unconfined Magnetic Field and Plasma Shielding etc.for defending the high-energy solar particle events (SPE) and Galactic Cosmic Rays (GCR) in deep space exploration.The concept of using cold plasma to expand a magnetic field is the best one of all possible methods so far.The magnetic field expansion caused by plasma can improve its protective efficiency of space particles.One kind of plasma generator has been developed and installed into the cylindrical permanent magnet in the eccentric.A plasma stream is produced using a helical-shaped antenna driven by a radio-frequency (RF) power supply of 13.56 MHz,which exits from both sides of the magnet and makes the magnetic field expand on one side.The discharging belts phenomenon is similar to the Earth's radiation belt,but the mechanism has yet to be understood.A magnetic probe is used to measure the magnetic field expansion distributions,and the results indicate that the magnetic field intensity increases under higher increments of the discharge power.

  19. The Electromagnetic Dipole Radiation Field through the Hamiltonian Approach

    Science.gov (United States)

    Likar, A.; Razpet, N.

    2009-01-01

    The dipole radiation from an oscillating charge is treated using the Hamiltonian approach to electrodynamics where the concept of cavity modes plays a central role. We show that the calculation of the radiation field can be obtained in a closed form within this approach by emphasizing the role of coherence between the cavity modes, which is…

  20. Radiative heat transfer in the extreme near field.

    Science.gov (United States)

    Kim, Kyeongtae; Song, Bai; Fernández-Hurtado, Víctor; Lee, Woochul; Jeong, Wonho; Cui, Longji; Thompson, Dakotah; Feist, Johannes; Reid, M T Homer; García-Vidal, Francisco J; Cuevas, Juan Carlos; Meyhofer, Edgar; Reddy, Pramod

    2015-12-17

    Radiative transfer of energy at the nanometre length scale is of great importance to a variety of technologies including heat-assisted magnetic recording, near-field thermophotovoltaics and lithography. Although experimental advances have enabled elucidation of near-field radiative heat transfer in gaps as small as 20-30 nanometres (refs 4-6), quantitative analysis in the extreme near field (less than 10 nanometres) has been greatly limited by experimental challenges. Moreover, the results of pioneering measurements differed from theoretical predictions by orders of magnitude. Here we use custom-fabricated scanning probes with embedded thermocouples, in conjunction with new microdevices capable of periodic temperature modulation, to measure radiative heat transfer down to gaps as small as two nanometres. For our experiments we deposited suitably chosen metal or dielectric layers on the scanning probes and microdevices, enabling direct study of extreme near-field radiation between silica-silica, silicon nitride-silicon nitride and gold-gold surfaces to reveal marked, gap-size-dependent enhancements of radiative heat transfer. Furthermore, our state-of-the-art calculations of radiative heat transfer, performed within the theoretical framework of fluctuational electrodynamics, are in excellent agreement with our experimental results, providing unambiguous evidence that confirms the validity of this theory for modelling radiative heat transfer in gaps as small as a few nanometres. This work lays the foundations required for the rational design of novel technologies that leverage nanoscale radiative heat transfer.

  1. Evaluation of uncertainty in field soil moisture estimations by cosmic-ray neutron sensing

    Science.gov (United States)

    Scheiffele, Lena Maria; Baroni, Gabriele; Schrön, Martin; Ingwersen, Joachim; Oswald, Sascha E.

    2017-04-01

    Cosmic-ray neutron sensing (CRNS) has developed into a valuable, indirect and non-invasive method to estimate soil moisture at the field scale. It provides continuous temporal data (hours to days), relatively large depth (10-70 cm), and intermediate spatial scale measurements (hundreds of meters), thereby overcoming some of the limitations in point measurements (e.g., TDR/FDR) and of remote sensing products. All these characteristics make CRNS a favorable approach for soil moisture estimation, especially for applications in cropped fields and agricultural water management. Various studies compare CRNS measurements to soil sensor networks and show a good agreement. However, CRNS is sensitive to more characteristics of the land-surface, e.g. additional hydrogen pools, soil bulk density, and biomass. Prior to calibration the standard atmospheric corrections are accounting for the effects of air pressure, humidity and variations in incoming neutrons. In addition, the standard calibration approach was further extended to account for hydrogen in lattice water and soil organic material. Some corrections were also proposed to account for water in biomass. Moreover, the sensitivity of the probe was found to decrease with distance and a weighting procedure for the calibration datasets was introduced to account for the sensors' radial sensitivity. On the one hand, all the mentioned corrections showed to improve the accuracy in estimated soil moisture values. On the other hand, they require substantial additional efforts in monitoring activities and they could inherently contribute to the overall uncertainty of the CRNS product. In this study we aim (i) to quantify the uncertainty in the field soil moisture estimated by CRNS and (ii) to understand the role of the different sources of uncertainty. To this end, two experimental sites in Germany were equipped with a CRNS probe and compared to values of a soil moisture network. The agricultural fields were cropped with winter

  2. Tomography of binomial states of the radiation field

    NARCIS (Netherlands)

    Bazrafkan, MR; Man'ko, [No Value

    2004-01-01

    The symplectic, optical, and photon-number tomographic symbols of binomial states of the radiation field are studied. Explicit relations for all tomograms of the binomial states are obtained. Two measures for nonclassical properties of these states are discussed.

  3. Tomography of binomial states of the radiation field

    NARCIS (Netherlands)

    Bazrafkan, MR; Man'ko, [No Value

    2004-01-01

    The symplectic, optical, and photon-number tomographic symbols of binomial states of the radiation field are studied. Explicit relations for all tomograms of the binomial states are obtained. Two measures for nonclassical properties of these states are discussed.

  4. Effect of near-earth thunderstorms electric field on the intensity of ground cosmic ray positrons/electrons in Tibet

    CERN Document Server

    Zhou, X X; Huang, D H; Jia, H Y

    2016-01-01

    Monte Carlo simulations are performed to study the correlation between the ground cosmic ray intensity and near-earth thunderstorms electric field at YBJ (4300 m a.s.l., Tibet, China). The variations of the secondary cosmic ray intensity are found to be highly dependent on the strength and polarity of the electric field. In negative fields and in positive fields greater than 600 V/cm, the total number of ground comic ray positrons and electrons increases with increasing electric field strength. And these values increase more obviously when involving a shower with lower primary energy or a higher zenith angle. While in positive fields ranging from 0 to 600 V/cm, the total number of ground comic ray positrons and electrons declines and the amplitude is up to 3.1% for vertical showers. A decrease of intensity occurs for inclined showers in positive fields less than 500 V/cm, which is accompanied by smaller amplitudes. In this paper, the intensity changes are discussed, especially concerning the decreases in posi...

  5. Cosmic rays on earth

    Energy Technology Data Exchange (ETDEWEB)

    Allkofer, O.C.; Grieder, P.K.F.

    1984-01-01

    A data collection is presented that covers cosmic rays on earth. Included are all relevant data on flux and intensity measurements, energy spectra, and related data of all primary and secondary components of the cosmic radiation at all levels in the atmosphere, at sea level and underground. In those cases where no useful experimental data have been available, theoretical predictions were substituted.

  6. Occurrence of BOOP outside radiation field after radiation therapy for small cell lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Hamanishi, Tohru; Oida, Kazukiyo [Tenri Hospital, Nara (Japan); Morimatu, Takafumi (and others)

    2001-09-01

    We report a case of bronchiolitis obliterans organizing pneumonia (BOOP) that occurred outside the radiation field after radiation therapy for small cell lung cancer. A 74-year-old woman received chemotherapy and a total of 60 Gy of radiation therapy to the right hilum and mediastinum for small cell carcinoma of the suprahilar area of the right lung. Radiation pneumonitis developed within the radiation port 3 months after the completion of radiation therapy. She complained of cough and was admitted 7 months after completion of the radiation therapy. Chest radiography and computed tomography demonstrated peripheral alveolar opacities outside the radiation field on the side contralateral to that receiving the radiation therapy. Bronchoalveolar lavage showed that the total cell count was increased, with a markedly increased percentage of lymphocytes. Transbronchial lung biopsy revealed a histologic pattern consistent with BOOP. Treatment with corticosteroids resulted in rapid improvement of the symptoms and complete resolution of the radiographic abnormalities of the left lung. Although some cases of BOOP following radiation therapy for breast cancer have been reported, none of BOOP after radiation therapy for lung cancer have appeared in the literature. (author)

  7. Atmospheric radiation modeling of galactic cosmic rays using LRO/CRaTER and the EMMREM model with comparisons to balloon and airline based measurements

    Science.gov (United States)

    Joyce, C. J.; Schwadron, N. A.; Townsend, L. W.; deWet, W. C.; Wilson, J. K.; Spence, H. E.; Tobiska, W. K.; Shelton-Mur, K.; Yarborough, A.; Harvey, J.; Herbst, A.; Koske-Phillips, A.; Molina, F.; Omondi, S.; Reid, C.; Reid, D.; Shultz, J.; Stephenson, B.; McDevitt, M.; Phillips, T.

    2016-09-01

    We provide an analysis of the galactic cosmic ray radiation environment of Earth's atmosphere using measurements from the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) aboard the Lunar Reconnaissance Orbiter (LRO) together with the Badhwar-O'Neil model and dose lookup tables generated by the Earth-Moon-Mars Radiation Environment Module (EMMREM). This study demonstrates an updated atmospheric radiation model that uses new dose tables to improve the accuracy of the modeled dose rates. Additionally, a method for computing geomagnetic cutoffs is incorporated into the model in order to account for location-dependent effects of the magnetosphere. Newly available measurements of atmospheric dose rates from instruments aboard commercial aircraft and high-altitude balloons enable us to evaluate the accuracy of the model in computing atmospheric dose rates. When compared to the available observations, the model seems to be reasonably accurate in modeling atmospheric radiation levels, overestimating airline dose rates by an average of 20%, which falls within the uncertainty limit recommended by the International Commission on Radiation Units and Measurements (ICRU). Additionally, measurements made aboard high-altitude balloons during simultaneous launches from New Hampshire and California provide an additional comparison to the model. We also find that the newly incorporated geomagnetic cutoff method enables the model to represent radiation variability as a function of location with sufficient accuracy.

  8. Cosmic confusion

    CERN Document Server

    Magueijo, J

    1994-01-01

    We propose to minimise the cosmic confusion between Gaussian and non Gaussian theories by investigating the structure in the m's for each multipole of the cosmic radiation temperature anisotropies. We prove that Gaussian theories are (nearly) the only theories which treat all the m's equally. Hence we introduce a set of invariant measures of ``m-preference'' to be seen as non-Gaussianity indicators. We then derive the distribution function for the quadrupole ``m-preference'' measure in Gaussian theories. A class of physically motivated toy non Gaussian theories is introduced as an example. We show how the quadrupole m-structure is crucial in reducing the confusion between these theories and Gaussian theories.

  9. Limits on the radiative decay of sterile neutrino dark matter from the unresolved cosmic and soft x-ray backgrounds

    Science.gov (United States)

    Abazajian, Kevork N.; Markevitch, Maxim; Koushiappas, Savvas M.; Hickox, Ryan C.

    2007-03-01

    We present upper limits on line emission in the Cosmic X-ray background (CXB) that would be produced by decay of sterile neutrino dark matter. We employ the spectra of the unresolved component of the CXB in the Chandra Deep Fields North and South obtained with the Chandra CCD detector in the E=0.8 9keV band. The expected decay flux comes from the dark matter on the lines of sight through the Milky Way galactic halo. Our constraints on the sterile neutrino decay rate are sensitive to the modeling of the Milky Way halo. The highest halo mass estimates provide a limit on the sterile neutrino mass of msrocket-borne calorimeter by McCammon and collaborators.

  10. The imprint of the cosmic supermassive black hole growth history on the 21 cm background radiation

    CERN Document Server

    Tanaka, Takamitsu L; Perna, Rosalba

    2015-01-01

    The redshifted 21 cm transition line of hydrogen tracks the thermal evolution of the neutral intergalactic medium (IGM) at "cosmic dawn," during the emergence of the first luminous astrophysical objects (~100 Myr after the Big Bang) but before these objects ionized the IGM (~400-800 Myr after the Big Bang). Because X-rays, in particular, are likely to be the chief energy courier for heating the IGM, measurements of the 21 cm signature can be used to infer knowledge about the first astrophysical X-ray sources. Using analytic arguments and a numerical population synthesis algorithm, we argue that the progenitors of supermassive black holes (SMBHs) should be the dominant source of hard astrophysical X-rays---and thus the primary driver of IGM heating and the 21 cm signature---at redshifts $z 20$. An absence of such a signature in the forthcoming observational data would imply that SMBH formation occurred later (e.g. via so-called direct collapse scenarios), that it was not a common occurrence in early galaxies ...

  11. Contamination cannot explain the lack of large-scale power in the cosmic microwave background radiation

    CERN Document Server

    Bunn, Emory F

    2008-01-01

    Several anomalies appear to be present in the large-angle cosmic microwave background (CMB) anisotropy maps of WMAP. One of these is a lack of large-scale power. Because the data otherwise match standard models extremely well, it is natural to consider perturbations of the standard model as possible explanations. We show that, as long as the source of the perturbation is statistically independent of the source of the primary CMB anisotropy, no such model can explain this large-scale power deficit. On the contrary, any such perturbation always reduces the probability of obtaining any given low value of large-scale power. We rigorously prove this result when the lack of large-scale power is quantified with a quadratic statistic, such as the quadrupole moment. When a statistic based on the integrated square of the correlation function is used instead, we present strong numerical evidence in support of the result. The result applies to models in which the geometry of spacetime is perturbed (e.g., an ellipsoidal U...

  12. Spherical Shell Cosmological Model and Uniformity of Cosmic Microwave Background Radiation

    CERN Document Server

    Vlahovic, Branislav

    2012-01-01

    Considered is spherical shell as a model for visible universe and parameters that such model must have to comply with the observable data. The topology of the model requires that motion of all galaxies and light must be confined inside a spherical shell. Consequently the observable universe cannot be defined as a sphere centered on the observer, rather it is an arc length within the volume of the spherical shell. The radius of the shell is 4.46 $\\pm$ 0.06 Gpc, which is for factor $\\pi$ smaller than radius of a corresponding 3-sphere. However the event horizon, defined as the arc length inside the shell, has the size of 14.0 $\\pm$ 0.2 Gpc, which is in agreement with the observable data. The model predicts, without inflation theory, the isotropy and uniformity of the CMB. It predicts the correct value for the Hubble constant $H_0$ = 67.26 $\\pm$ 0.90 km/s/Mpc, the cosmic expansion rate $H(z)$, and the speed of the event horizon in agreement with observations. The theoretical suport for shell model comes from gen...

  13. Constraints on AGN feedback from its Sunyaev-Zel'dovich imprint on the cosmic background radiation

    Science.gov (United States)

    Soergel, Bjoern; Giannantonio, Tommaso; Efstathiou, George; Puchwein, Ewald; Sijacki, Debora

    2017-06-01

    We derive constraints on feedback by active galactic nuclei (AGN) by setting limits on their thermal Sunyaev-Zel'dovich (SZ) imprint on the cosmic microwave background. The amplitude of any SZ signature is small and degenerate with the poorly known sub-mm spectral energy distribution of the AGN host galaxy and other unresolved dusty sources along the line of sight. Here we break this degeneracy by combining microwave and sub-mm data from Planck with all-sky far-infrared maps from the AKARI satellite. We first test our measurement pipeline using the Sloan Digital Sky Survey (SDSS) redMaPPer catalogue of galaxy clusters, finding a highly significant detection (>20σ) of the SZ effect together with correlated dust emission. We then constrain the SZ signal associated with spectroscopically confirmed quasi-stellar objects (QSOs) from SDSS data release 7 (DR7) and the Baryon Oscillation Spectroscopic Survey (BOSS) DR12. We obtain a low-significance (1.6σ) hint of an SZ signal, pointing towards a mean thermal energy of ≃5 × 1060 erg, lower than reported in some previous studies. A comparison of our results with high-resolution hydrodynamical simulations including AGN feedback suggests QSO host masses of M200c ˜ 4 × 1012 h-1 M⊙, but with a large uncertainty. Our analysis provides no conclusive evidence for an SZ signal specifically associated with AGN feedback.

  14. Development of advanced radiation monitors for pulsed neutron fields

    CERN Document Server

    AUTHOR|(CDS)2081895

    The need of radiation detectors capable of efficiently measuring in pulsed neutron fields is attracting widespread interest since the 60s. The efforts of the scientific community substantially increased in the last decade due to the increasing number of applications in which this radiation field is encountered. This is a major issue especially at particle accelerator facilities, where pulsed neutron fields are present because of beam losses at targets, collimators and beam dumps, and where the correct assessment of the intensity of the neutron fields is fundamental for radiation protection monitoring. LUPIN is a neutron detector that combines an innovative acquisition electronics based on logarithmic amplification of the collected current signal and a special technique used to derive the total number of detected neutron interactions, which has been specifically conceived to work in pulsed neutron fields. Due to its special working principle, it is capable of overcoming the typical saturation issues encountere...

  15. Footprint Characteristics Revised for Field-Scale Soil Moisture Monitoring with Cosmic-Ray Neutrons

    CERN Document Server

    Köhli, M; Zreda, M; Schmidt, U; Dietrich, P; Zacharias, S

    2016-01-01

    Cosmic-ray neutron probes are widely used to monitor environmental water content near the surface. The method averages over tens of hectares and is unrivaled in serving representative data for agriculture and hydrological models at the hectometer scale. Recent experiments, however, indicate that the sensor response to environmental heterogeneity is not fully understood. Knowledge of the support volume is a prerequisite for the proper interpretation and validation of hydrogeophysical data. In a previous study, several physical simplifications have been introduced into a neutron transport model in order to derive the characteristics of the cosmic-ray probe's footprint. We utilize a refined source and energy spectrum for cosmic-ray neutrons and simulate their response to a variety of environmental conditions. Results indicate that the method is particularly sensitive to soil moisture in the first tens of meters around the probe, whereas the radial weights are changing dynamically with ambient water. The footprin...

  16. The effect of early radiation in N-body simulations of cosmic structure formation

    DEFF Research Database (Denmark)

    Adamek, Julian; Brandbyge, Jacob; Fidler, Christian

    2017-01-01

    Newtonian N-body simulations have been employed successfully over the past decades for the simulation of the cosmological large-scale structure. Such simulations usually ignore radiation perturbations (photons and massless neutrinos) and the impact of general relativity (GR) beyond the background...

  17. Polarized radiation diagnostics of stellar magnetic fields

    Science.gov (United States)

    Mathys, Gautier

    The main techniques used to diagnose magnetic fields in stars from polarimetric observations are presented. First, a summary of the physics of spectral line formation in the presence of a magnetic field is given. Departures from the simple case of linear Zeeman effect are briefly considered: partial Paschen-Back effect, contribution of hyperfine structure, and combined Stark and Zeeman effects. Important approximate solutions of the equation of transfer of polarized light in spectral lines are introduced. The procedure for disk-integration of emergent Stokes profiles, which is central to stellar magnetic field studies, is described, with special attention to the treatment of stellar rotation. This formalism is used to discuss the determination of the mean longitudinal magnetic field (through the photographic technique and through Balmer line photopolarimetry). This is done within the specific framework of Ap stars, which, with their unique large-scale organized magnetic fields, are an ideal laboratory for studies of stellar magnetism. Special attention is paid to those Ap stars whose magnetically split line components are resolved in high-dispersion Stokes I spectra, and to the determination of their mean magnetic field modulus. Various techniques of exploitation of the information contained in polarized spectral line profiles are reviewed: the moment technique (in particular, the determination of the crossover and of the mean quadratic field), Zeeman-Doppler imaging, and least-squares deconvolution. The prospects that these methods open for linear polarization studies are sketched. The way in which linear polarization diagnostics complement their Stokes I and V counterparts is emphasized by consideration of the results of broad band linear polarization measurements. Illustrations of the use of various diagnostics to derive properties of the magnetic fields of Ap stars are given. This is used to show the interest of deriving more physically realistic models of the

  18. Nuclear Radiation Fields on the Mars Surface: Risk Analysis for Long-term Living Environment

    Science.gov (United States)

    Anderson, Brooke M.; Clowdsley, Martha S.; Qualls, Garry D.; Nealy, John E.

    2005-01-01

    Mars, our nearest planet outward from the sun, has been targeted for several decades as a prospective site for expanded human habitation. Background space radiation exposures on Mars are expected to be orders of magnitude higher than on Earth. Recent risk analysis procedures based on detailed dosimetric techniques applicable to sensitive human organs have been developed along with experimental data regarding cell mutation rates resulting from exposures to a broad range of particle types and energy spectra. In this context, simulated exposure and subsequent risk for humans in residence on Mars are examined. A conceptual habitat structure, CAD-modeled with duly considered inherent shielding properties, has been implemented. Body self-shielding is evaluated using NASA standard computerized male and female models. The background environment is taken to consist not only of exposure from incident cosmic ray ions and their secondaries, but also include the contribution from secondary neutron fields produced in the tenuous atmosphere and the underlying regolith.

  19. Correlation analysis of gamma dose rate from natural radiation in the test field

    Directory of Open Access Journals (Sweden)

    Avdic Senada

    2016-01-01

    Full Text Available This paper deals with correlation analysis of gamma dose rate measured in the test field with the five distinctive soil samples from a few minefields in Federation of Bosnia and Herzegovina. The measurements of ambient dose equivalent rate, due to radionuclides present in each of the soil samples, were performed by the RADIAGEMTM 2000 portable survey meter, placed on the ground and 1m above the ground. The gamma spectrometric analysis of the same soil samples was carried out by GAMMA-RAD5 spectrometer. This study showed that there is a high correlation between the absorbed dose rate evaluated from soil radioactivity and the corresponding results obtained by the survey meter placed on the ground. Correlation analysis indicated that the survey meter, due to its narrow energy range, is not suitable for the examination of cosmic radiation contribution.

  20. Cosmic rays, clouds, and climate

    DEFF Research Database (Denmark)

    Marsh, N.; Svensmark, Henrik

    2000-01-01

    cloud radiative properties. Thus, a moderate influence on atmospheric aerosol distributions from cosmic ray ionisation would have a strong influence on the Earth's radiation budget. Historical evidence over the past 1000 years indicates that changes in climate have occurred in accord with variability...... in the Earth's radiation budget through trapping outgoing radiation and reflecting incoming radiation. If a physical link between these two features can be established, it would provide a mechanism linking solar activity and Earth's climate. Recent satellite observations have further revealed a correlation...... in cosmic ray intensities. Such changes are in agreement with the sign of cloud radiative forcing associated with cosmic ray variability as estimated from satellite observations....

  1. Radiation (absorbing) boundary conditions for electromagnetic fields

    Science.gov (United States)

    Bevensee, R. M.; Pennock, S. T.

    1987-01-01

    An important problem in finite difference or finite element computation of the electromagnetic field obeying the space-time Maxwell equations with self-consistent sources is that of truncating the outer numerical boundaries properly to avoid spurious numerical reflection. Methods for extrapolating properly the fields just beyond a numerical boundary in free space have been treated by a number of workers. This report avoids plane wave assumptions and derives boundary conditions more directly related to the source distribution within the region. The Panofsky-Phillips' relations, which enable one to extrapolate conveniently the vector field components parallel and perpendicular to a radial from the coordinate origin chosen near the center of the charge-current distribution are used to describe the space-time fields.

  2. The effect of early radiation in N-body simulations of cosmic structure formation

    Science.gov (United States)

    Adamek, Julian; Brandbyge, Jacob; Fidler, Christian; Hannestad, Steen; Rampf, Cornelius; Tram, Thomas

    2017-09-01

    Newtonian N-body simulations have been employed successfully over the past decades for the simulation of the cosmological large-scale structure. Such simulations usually ignore radiation perturbations (photons and massless neutrinos) and the impact of general relativity (GR) beyond the background expansion. This approximation can be relaxed and we discuss three different approaches that are accurate to leading order in GR. For simulations that start at redshift less than about 100, we find that the presence of early radiation typically leads to per cent-level effects on the numerical power spectra at large scales. Our numerical results agree across the three methods, and we conclude that all of the three methods are suitable for simulations in a standard cosmology. Two of the methods modify the N-body evolution directly, while the third method can be applied as a post-processing prescription.

  3. Self-organization of cosmic radiation pressure instability. II - One-dimensional simulations

    Science.gov (United States)

    Hogan, Craig J.; Woods, Jorden

    1992-01-01

    The clustering of statistically uniform discrete absorbing particles moving solely under the influence of radiation pressure from uniformly distributed emitters is studied in a simple one-dimensional model. Radiation pressure tends to amplify statistical clustering in the absorbers; the absorbing material is swept into empty bubbles, the biggest bubbles grow bigger almost as they would in a uniform medium, and the smaller ones get crushed and disappear. Numerical simulations of a one-dimensional system are used to support the conjecture that the system is self-organizing. Simple statistics indicate that a wide range of initial conditions produce structure approaching the same self-similar statistical distribution, whose scaling properties follow those of the attractor solution for an isolated bubble. The importance of the process for large-scale structuring of the interstellar medium is briefly discussed.

  4. Radiation-damped profiles of extremely high column density neutral hydrogen: implications of cosmic reionization

    Science.gov (United States)

    Bach, Kiehunn

    2017-01-01

    Incorporating the time-dependent second-order perturbation theory for the Lyman scattering cross-section, we investigate the intergalactic absorption profiles of extremely high column density systems near the end of cosmic reionization. Assuming a representative set of the redshift distribution of neutral hydrogen, we quantitatively examined the impact of inhomogeneous density on the intrinsic absorption profiles. The cumulative absorption by neutral patches in the line of sight mainly affects the far off-centre region of the red damping wing, but the effect is not significant. The shape of the line centre can be modified by the near-zone distribution due to high opacities of the near-resonance scattering. On the other hand, the HWHM (half width at half-maximum) as an effective line width is relatively less sensitive to the local inhomogeneity. Specifically, when the two local damping wings of Lyα and Lyβ are close in spectra of the strongly damped systems, accurate profiles of both lines are required. In the case of N_{H I}≲ 10^{21} { cm^{-2}}, the two-level approximation is marginally applicable for the damping wing fit within 5 - 7 per cent errors. However, as the local column density reaches N_{H I}˜ 10^{22.3} { cm^{-2}}, this classical approximation yields a relative error of a 10 per cent overestimation in the red wing and a 20 per cent underestimation in the blue wing of Lyα. If severe extinction by the Lyα forests is carefully subtracted, the intrinsic absorption profile will provide a better constraint on the local ionized states. For practical applications, an analytic fitting function for the Lyβ scattering is derived.

  5. Radiation Damped Profiles of Extremely High Column Density Neutral Hydrogen : Implications of Cosmic Reionization

    Science.gov (United States)

    Bach, Kiehunn

    2016-09-01

    Incorporating the time-dependent second-order perturbation theory for the Lyman scattering cross-section, we investigate the intergalactic absorption profiles of extremely high column density systems near the end of cosmic reionization. Assuming a representative set of the redshift distribution of neutral hydrogen, we quantitatively examined the impact of inhomogeneous density on the intrinsic absorption profiles. The cumulative absorption by neutral patches in the line-of-sight mainly affects the far off-center region of the red damping wing, but the effect is not significant. The shape of the line-center can be modified by the near-zone distribution due to high opacities of the near-resonance scattering. On the other hand, the HWHM (half width at half maximum) as an effective line-width is relatively less sensitive to the local inhomogeneity. Specifically, when the two local damping wings of Lyα and Lyβ are close in spectra of the strongly damped systems, accurate profiles of both lines are required. In the case of N HI ≲ 1021 cm-2, the two-level approximation is marginally applicable for the damping wing fit within 5 - 7% errors. However, as the local column density reaches N HI ˜ 1022.3 cm-2, this classical approximation yields a relative error of a 10% overestimation in the red wing and a 20% underestimation in the blue wing of Lyα. If severe extinction by the Lyα forests is carefully subtracted, the intrinsic absorption profile will provide a better constraint on the local ionized states. For practical applications, an analytic fitting function for the Lyβ scattering is derived.

  6. Ralph A. Alpher, George Antonovich Gamow, and the Prediction of the Cosmic Microwave Background Radiation

    CERN Document Server

    Alpher, Victor S

    2014-01-01

    The first prediction of the existence of "relict radiation" or radiation remaining from the "Big Bang" was made in 1948. This derived from the seminal dissertation work of Ralph A. Alpher. He was a doctoral student of George A. Gamow and developed several critical advances in cosmology in late 1946, 1947, and 1948. Alpher developed the ideas of "hot" big bang cosmology to a high degree of physical precision, and was the first to present the idea that radiation, not matter, predominated the early universal adiabatic expansion first suggested by A. Friedmann in the early 1920s. Alpher and Herman predicted the residual relic black-body temperature in 1948 and 1949 at around 5 K. However, to this day, this prediction, and other seminal ideas in big bang cosmology, have often been attributed erroneously to the better-known George A. Gamow. This article reviews some of the more egregious and even farcical errors in the scholarly literature about Ralph A. Alpher and his place in the history of big bang cosmology. Tw...

  7. Sound power radiated by sources in diffuse fields

    DEFF Research Database (Denmark)

    Polack, Jean-Dominique

    2000-01-01

    Sound power radiated by sources at low frequency notoriously depends on source position. We sampled the sound field of a rectangular room at 18 microphone and 4 source positions. Average power spectra were extrapolated from the reverberant field, taking into account the frequency dependent...... reverberation times. They reveal fluctuations that depend on source position and extend far above Schroeder frequency....

  8. Field calibration studies for ionisation chambers in mixed high-energy radiation fields.

    Science.gov (United States)

    Theis, C; Forkel-Wirth, D; Fuerstner, M; Mayer, S; Otto, Th; Roesler, S; Vincke, H

    2007-01-01

    The monitoring of ambient doses at work places around high-energy accelerators is a challenging task due the complexity of the mixed stray radiation fields encountered. At CERN, mainly Centronics IG5 high-pressure ionisation chambers are used to monitor radiation exposure in mixed fields. The monitors are calibrated in the operational quantity ambient dose equivalent H*(10) using standard, source-generated photon- and neutron fields. However, the relationship between ionisation chamber reading and ambient dose equivalent in a mixed high-energy radiation field can only be assessed if the spectral response to every component and the field composition is known. Therefore, comprehensive studies were performed at the CERN-EU high-energy reference field facility where the spectral fluence for each particle type has been assessed with Monte Carlo simulations. Moreover, studies have been performed in an accessible controlled radiation area in the vicinity of a beam loss point of CERN's proton synchrotron. The comparison of measurements and calculations has shown reasonable agreement for most exposure conditions. The results indicate that conventionally calibrated ionisation chambers can give satisfactory response in terms of ambient dose equivalent in stray radiation fields at high-energy accelerators in many cases. These studies are one step towards establishing a method of 'field calibration' of radiation protection instruments in which Monte Carlo simulations will be used to establish a correct correlation between the response of specific detectors to a given high-energy radiation field.

  9. Structural analysis of the SDSS Cosmic Web - I. Non-linear density field reconstructions

    NARCIS (Netherlands)

    Platen, Erwin; van de Weygaert, Rien; Jones, Bernard J. T.; Vegter, Gert; Calvo, Miguel A. Aragón

    2011-01-01

    This study is the first in a series in which we analyse the structure and topology of the Cosmic Web as traced by the Sloan Digital Sky Survey (SDSS). The main issue addressed in the present study is the translation of the irregularly distributed discrete spatial data in the galaxy redshift survey i

  10. Structural analysis of the SDSS Cosmic Web : I. Non-linear density field reconstructions

    NARCIS (Netherlands)

    Platen, Erwin; Weygaert, Rien van de; Jones, Bernard J.T.; Vegter, Gert; Aragón Calvo, Miguel A.

    2011-01-01

    This study is the first in a series in which we analyse the structure and topology of the Cosmic Web as traced by the Sloan Digital Sky Survey (SDSS). The main issue addressed in the present study is the translation of the irregularly distributed discrete spatial data in the galaxy redshift survey i

  11. On the Long-Term Variation of Galactic Cosmic Rays: Convection-Diffusion and Drift Modulations in the Heliosphere, Expected Radiation Hazard

    Science.gov (United States)

    Dorman, Lev

    On the basis of results obtained in our investigations of CR-SA hysteresis effects we determine the dimension of Heliosphere (modulation region), radial diffusion coefficient and other param-eters of convection-diffusion and drift mechanisms of cosmic ray (CR) long term variation in dependence of particles energy, level of solar activity (SA) and general solar magnetic field. This important information we obtain on the basis of CR and SA data in the past taking into account the theory of convection-diffusion and drift global modulation of galactic CR in the Heliosphere. By using these results and published regularly elsewhere predictions of expected sunspot number variation in near future and prediction of future next SA cycle we may made prediction of expected in near future (up to 10-12 years) long-term CR intensity variation. From other hand, we use estimated properties of connection between CR intensity long-term variation and some part of global climate change, controlled by solar activity through CR. We show that by this way we may made prediction of expected in near future (up to 10-12 years) radiation hazard from galactic CR in interplanetary space at different distances from the Sun (what is important for space probes and long-term missions to Mars and other planets and their satellites) and long-living objects on different orbits in the Earth's magnetosphere, as well as in the Earth's atmosphere (e.g. for airplanes at altitude about 10 km). Let us underline that in the last two cases become important to take into account also expected long-term changes in the planetary distribution of cutoff rigidities, which also influenced on observed galactic CR intensity, and corresponding radiation hazard.

  12. PyCosmic: A robust method to detect cosmics in CALIFA and other fiber-fed integral-field spectroscopy datasets

    CERN Document Server

    Husemann, B; Sandin, C; Sánchez, S F; García-Benito, R; Mast, D

    2012-01-01

    [Abridged] Detecting cosmic ray hits (cosmics) in fiber-fed IFS data of single exposures is a challenging task, because of the complex signal recorded by IFS instruments. Existing detection algorithms are commonly found to be unreliable in the case of IFS data and the optimal parameter settings are usually unknown a-priori for a given dataset. The CALIFA survey generates hundreds of IFS datasets for which a reliable and robust detection algorithm for cosmics is required as an important part of the fully automatic CALIFA data reduction pipeline. We developed a novel algorithm, PyCosmic, which combines the edge-detection algorithm of L.A.Cosmic with a point-spread function convolution scheme. We generated mock data to compute the efficiency of different algorithms for a wide range of characteristic fibre-fed IFS datasets using the PMAS and VIMOS IFS instruments as representative cases. PyCosmic is the only algorithm that achieves an acceptable detection performance for CALIFA data. We find that PyCosmic is the ...

  13. Radiative transfer in a clumpy universe: IV. New synthesis models of the cosmic UV/X-ray background

    CERN Document Server

    Haardt, Francesco

    2011-01-01

    We present improved synthesis models of the evolving spectrum of the UV/X-ray diffuse background, updating and extending our previous results. Five new main components are added to our radiative transfer code CUBA: (1) the sawtooth modulation of the background intensity from resonant line absorption in the Lyman series of cosmic hydrogen and helium; (2) the X-ray emission from obscured and unobscured quasars; (3) a piecewise parameterization of the distribution in redshift and column density of intergalactic absorbers that fits recent measurements of the mean free path of 1 ryd photons; (4) an accurate treatment of the photoionization structure of absorbers; and (5) the UV emission from star-forming galaxies at all redshifts. We provide tables of the predicted HI and HeII photoionization and photoheating rates for use, e.g., in cosmological hydrodynamics simulations of the Lya forest, and a new metallicity-dependent calibration to the UV luminosity density-star formation rate density relation. A "minimal cosm...

  14. Monte Carlo simulation of the Cherenkov radiation emitted by TeO{sub 2} crystal when crossed by cosmic muons

    Energy Technology Data Exchange (ETDEWEB)

    Casali, N., E-mail: nicola.casali@gmail.com [Dipartimento di Scienze Fisiche e Chimiche, Università degli studi dell' Aquila, Coppito (AQ) (Italy); Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Gran Sasso, Assergi (AQ) (Italy); Bellini, F. [Sapienza Università di roma, P.le A. Moro 2, Roma (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Roma, P.le A. Moro 2, Roma (Italy); Dafinei, I. [Istituto Nazionale di Fisica Nucleare, Sezione di Roma, P.le A. Moro 2, Roma (Italy); Marafini, M. [Museo Storico della Fisisca e Centro Studi e Ricerche “Enrico Fermi“, Piazza del Viminale 1, Roma (Italy); Morganti, S.; Orio, F.; Pinci, D.; Vignati, M.; Voena, C. [Istituto Nazionale di Fisica Nucleare, Sezione di Roma, P.le A. Moro 2, Roma (Italy)

    2013-12-21

    TeO{sub 2} crystals are currently used as bolometric detectors in experiments searching for the neutrinoless double beta decay of {sup 130}Te. The extreme rarity of the studied signal forces the experiments to reach an ultra low background level. The main background source is represented by α particles emitted by radioactive contaminants placed in the materials that compose and surround the detector. Recent measurements show that a particle discrimination in TeO{sub 2} bolometers detecting the light emitted by β/γ particles is possible, opening the possibility to make large improvements in the performance of experiments based on this kind of materials. In order to understand the nature of this light emission a measurement at room temperature with TeO{sub 2} crystals was performed. According to these results, the detected light was compatible with the Cherenkov emission, even though the scintillation hypothesis could not be discarded. In this work a Monte Carlo (MC) simulation of the Cherenkov radiation emitted by TeO{sub 2} crystal when crossed by cosmic muons was performed. The data from MC and the room temperature measurement are perfectly compatible and prove that the Cherenkov light is the only component of the light yield of TeO{sub 2} crystals.

  15. Energy spectrum and mass composition of primary cosmic radiation in the region above the knee from the GAMMA experiment

    CERN Document Server

    Martirosov, R M; Vardanyan, H S; Erlykin, A D; Nikolskaya, N M; Gallant, Y A; Jones, L W; Babayan, H A

    2012-01-01

    The energy spectrum of the primary cosmic radiation in the energy range 1 - 100 PeV and the extensive air shower (EAS) characteristics obtained on the basis of the expanded data bank of the GAMMA experiment (Mt. Aragats, Armenia) are presented. With increased statistics we confirm our previous results on the energy spectrum. The spectral index above the knee is about -3.1, but at energies beyond 20 PeV a flattening of the spectrum is observed. The existence of the 'bump' at about 70 PeV is confirmed with a significance of more than 4{\\sigma}. In the energy range of 10 - 100 PeV the shower age becomes energy independent and we observe a direct proportionality of the EAS size to the primary energy. This suggests an approximately constant depth of the EAS maximum in this energy range. This is evidence in favour of an increasing average mass of primary particles at energies above 20 PeV. The additional source scenario, which is a possible explanation of the 'bump' in the spectrum, also leads to the conclusion of ...

  16. Measurements of the anisotropy of the cosmic background radiation and diffuse galactic emission at millimeter and submillimeter wavelengths

    Science.gov (United States)

    Halpern, Mark; Benford, Richard; Meyer, Stephan; Muehlner, Dirk; Weiss, Rainer

    1988-01-01

    The results of a balloon-borne observing program to measure the large angular scale brightness distribution of the 2.7 K cosmic background radiation (CBR) at millimeter and submillimeter wavelengths are reported. A new determination of the dipole anisotropy of the CBR is found with 3.40 + or - 0.42 mK toward alpha = 12.1 + or - 0.24 hr, delta = - 23 + or - 5 deg in a 1.2 to 8/cm band and 4.7 + or - 1.4 mK toward alpha = 9.9 + 1.7 or - 1.1 hr, delta = - 38 + or - 21 deg between 5 and 18/cm, where the amplitudes are listed as thermodynamic temperatures. New estimates of the absolute temperature in these two bands of 2.86 + or - 0.26 K and 3.01 + or - 0.31 are obtained under the assumption that the CBR has a Planck spectrum. The diffuse Galactic emission is fitted by a secant distribution in Galactic latitude, and the resulting Galactic pole antenna temperatures are given. Maps of sky brightness, measurements of zodiacal emission, and measurements of fluctuations of the atmospheric emission which dominates the noise budget are also presented.

  17. Early results from the MIT millimeter and sub-millimeter balloon-borne anisotropy measurement. [of cosmic microwave background radiation

    Science.gov (United States)

    Meyer, Stephan S.; Cheng, Edward S.; Page, Lyman A.

    1991-01-01

    The MIT balloon-borne bolometric search for Cosmic Microwave Background Radiation (CMBR) anisotropies places the most stringent constraints to date on fluctuations in the CMBR. Four maps of half of the Northern Hemisphere at 1.8, 1.1, 0.63 and 0.44 mm wavelength, have a beam size of 3.8 deg with a 1 sigma sensitivity of less than 0.1 mK (thermodynamic) per FOV in each of the first two channels. Analysis of the sky map at 1.8 mm wavelength using a likelihood ratio test for galactic latitudes of 15 deg and greater yields a 95 percent confidence level (CL) upper limit on fluctuations of the CMBR at DeltaT/T less than or equal to 1.6 x 10 exp -5 with a statistical power of 92 percent for Gaussian fluctuations at a correlation angle of 13 deg. Between 3 deg and 22 deg, the upper limit for fluctuations is DeltaT/T less than or equal to 4.0 x 10 exp -5 (95 percent CL).

  18. A Bridge from Optical to Infrared Galaxies Explaining Local Properties, Predicting Galaxy Counts and the Cosmic Background Radiation

    CERN Document Server

    Totani, T; Totani, Tomonori; Takeuchi, Tsutomu T.

    2002-01-01

    We give an explanation for the origin of various properties observed in local infrared galaxies, and make predictions for galaxy counts and cosmic background radiation (CBR), by a new model extended from that for optical/near-infrared galaxies. Important new characteristics of this study are that (1) mass scale dependence of dust extinction is introduced based on the size-luminosity relation of optical galaxies, and that (2) the big grain dust temperature T_dust is calculated based on a physical consideration for energy balance, rather than using the empirical relation between T_dust and total infrared luminosity L_IR found in local galaxies, which has been employed in most of previous works. Consequently, the local properties of infrared galaxies, i.e., optical/infrared luminosity ratios, L_IR-T_dust correlation, and infrared luminosity function are outputs predicted by the model. Our model indeed reproduces these local properties reasonably well. We then found considerably different results for MIR-submm co...

  19. Estimation of occupational cosmic radiation exposure among airline personnel: Agreement between a job-exposure matrix, aggregate, and individual dose estimates.

    Science.gov (United States)

    Talibov, Madar; Salmelin, Raili; Lehtinen-Jacks, Susanna; Auvinen, Anssi

    2017-04-01

    Job-exposure matrices (JEM) are used for exposure assessment in occupational studies, but they can involve errors. We assessed agreement between the Nordic Occupational Cancer Studies JEM (NOCCA-JEM) and aggregate and individual dose estimates for cosmic radiation exposure among Finnish airline personnel. Cumulative cosmic radiation exposure for 5,022 airline crew members was compared between a JEM and aggregate and individual dose estimates. The NOCCA-JEM underestimated individual doses. Intraclass correlation coefficient was 0.37, proportion of agreement 64%, kappa 0.46 compared with individual doses. Higher agreement was achieved with aggregate dose estimates, that is annual medians of individual doses and estimates adjusted for heliocentric potentials. The substantial disagreement between NOCCA-JEM and individual dose estimates of cosmic radiation may lead to exposure misclassification and biased risk estimates in epidemiological studies. Using aggregate data may provide improved estimates. Am. J. Ind. Med. 60:386-393, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  20. Removing cosmic-ray hits from multiorbit HST Wide Field Camera images

    Science.gov (United States)

    Windhorst, Rogier A.; Franklin, Barbara E.; Neuschaefer, Lyman W.

    1994-01-01

    We present an optimized algorithm that removes cosmic rays ('CRs') from multiorbit Hubble Space Telescope (HST) Wide Field/Planetary Camera ('WF/PC') images. It computes the image noise in every iteration from the WF/PC CCD equation. This includes all known sources of random and systematic calibration errors. We test this algorithm on WF/PC stacks of 2-12 orbits as a function of the number of available orbits and the formal Poissonian sigma-clipping level. We find that the algorithm needs greater than or equal 4 WF/PC exposures to locate the minimal sky signal (which is noticeably affected by CRs), with an optimal clipping level at 2-2.5 x sigma(sub Poisson). We analyze the CR flux detected on multiorbit 'CR stacks,' which are constructed by subtracting the best CR filtered images from the unfiltered 8-12 orbit average. We use an automated object finder to determine the surface density of CRS as a function of the apparent magnitude (or ADU flux) they would have generated in the images had they not been removed. The power law slope of the CR 'counts' (gamma approximately = 0.6 for N(m) m(exp gamma)) is steeper than that of the faint galaxy counts down to V approximately = 28 mag. The CR counts show a drop off between 28 less than or approximately V less than or approximately 30 mag (the latter is our formal 2 sigma point source sensitivity without spherical aberration). This prevents the CR sky integral from diverging, and is likely due to a real cutoff in the CR energy distribution below approximately 11 ADU per orbit. The integral CR surface density is less than or approximately 10(exp 8)/sq. deg, and their sky signal is V approximately = 25.5-27.0 mag/sq. arcsec, or 3%-13% of our NEP sky background (V = 23.3 mag/sq. arcsec), and well above the EBL integral of the deepest galaxy counts (B(sub J) approximately = 28.0 mag/sq. arcsec). We conclude that faint CRs will always contribute to the sky signal in the deepest WF/PC images. Since WFPC2 has approximately 2.7x

  1. Spontaneous Radiation Emission from Short, High Field Strength Insertion Devices

    Energy Technology Data Exchange (ETDEWEB)

    Geoffrey Krafft

    2005-09-15

    Since the earliest papers on undulaters were published, it has been known how to calculate the spontaneous emission spectrum from ''short'' undulaters when the magnetic field strength parameter is small compared to unity, or in ''single'' frequency sinusoidal undulaters where the magnetic field strength parameter is comparable to or larger than unity, but where the magnetic field amplitude is constant throughout the undulater. Fewer general results have been obtained in the case where the insertion device is both short, i.e., the magnetic field strength parameter changes appreciably throughout the insertion device, and the magnetic field strength is high enough that ponderomotive effects, radiation retardation, and harmonic generation are important physical phenomena. In this paper a general method is presented for calculating the radiation spectrum for short, high-field insertion devices. It is used to calculate the emission from some insertion device designs of recent interest.

  2. Spontaneous radiation emission from short, high field strength magnetic devices

    Directory of Open Access Journals (Sweden)

    G. A. Krafft

    2006-01-01

    Full Text Available Since the earliest papers on undulators were published, it has been known how to calculate the spontaneous emission spectrum from short undulators when the magnetic field strength parameter is small compared to unity, or in “single” frequency sinusoidal undulators where the magnetic field strength parameter is comparable to or larger than unity, but where the magnetic field amplitude is constant throughout the undulator. Fewer general results have been obtained in the case where the magnetic device is both short, i.e., the magnetic field strength parameter changes appreciably throughout the device, and the magnetic field strength is high enough that ponderomotive effects, radiation retardation, and harmonic generation are important physical phenomena. In this paper a general method is presented for calculating the radiation spectrum for short, high-field magnetic devices. It is used to calculate the emission from some designs of recent interest.

  3. Results of Simulated Galactic Cosmic Radiation (GCR) and Solar Particle Events (SPE) on Spectra Restraint Fabric

    Science.gov (United States)

    Peters, Benjamin; Hussain, Sarosh; Waller, Jess

    2017-01-01

    Spectra or similar Ultra-high-molecular-weight polyethylene (UHMWPE) fabric is the likely choice for future structural space suit restraint materials due to its high strength-to-weight ratio, abrasion resistance, and dimensional stability. During long duration space missions, space suits will be subjected to significant amounts of high-energy radiation from several different sources. To insure that pressure garment designs properly account for effects of radiation, it is important to characterize the mechanical changes to structural materials after they have been irradiated. White Sands Test Facility (WSFTF) collaborated with the Crew and Thermal Systems Division at the Johnson Space Center (JSC) to irradiate and test various space suit materials by examining their tensile properties through blunt probe puncture testing and single fiber tensile testing after the materials had been dosed at various levels of simulated GCR and SPE Iron and Proton beams at Brookhaven National Laboratories. The dosages were chosen based on a simulation developed by the Structural Engineering Division at JSC for the expected radiation dosages seen by space suit softgoods seen on a Mars reference mission. Spectra fabric tested in the effort saw equivalent dosages at 2x, 10x, and 20x the predicted dose as well as a simulated 50 year exposure to examine the range of effects on the material and examine whether any degradation due to GCR would be present if the suit softgoods were stored in deep space for a long period of time. This paper presents the results of this work and outlines the impact on space suit pressure garment design for long duration deep space missions.

  4. Field Testing of a Portable Radiation Detector and Mapping System

    Energy Technology Data Exchange (ETDEWEB)

    Hofstetter, K.J. [Westinghouse Savannah River Company, AIKEN, SC (United States); Hayes, D.W.; Eakle, R.F.

    1998-03-01

    Researchers at the Savannah River Site (SRS) have developed a man- portable radiation detector and mapping system (RADMAPS) which integrates the accumulation of radiation information with precise ground locations. RADMAPS provides field personnel with the ability to detect, locate, and characterize nuclear material at a site or facility by analyzing the gamma or neutron spectra and correlating them with position. the man-portable field unit records gamma or neutron count rate information and its location, along with date and time, using an embedded Global Positioning System (GPS). RADMAPS is an advancement in data fusion, integrating several off-the-shelf technologies with new computer software resulting in a system that is simple to deploy and provides information useful to field personnel in an easily understandable form. Decisions on subsequent actions can be made in the field to efficiently use available field resources. The technologies employed in this system include: recording GPS, radiation detection (typically scintillation detectors), pulse height analysis, analog-to-digital converters, removable solid-state (Flash or SRAM) memory cards, Geographic Information System (GIS) software and personal computers with CD-ROM supporting digital base maps. RADMAPS includes several field deployable data acquisition systems designed to simultaneously record radiation and geographic positions. This paper summarizes the capabilities of RADMAPS and some of the results of field tests performed with the system.

  5. The dielectric response to the magnetic field of electromagnetic radiation

    Science.gov (United States)

    Mukherjee, Shouvik; Mukhopadhyay, Sourabh; Datta, Prasanta Kumar

    2017-04-01

    Light–matter interaction in transparent dielectrics is revisited, including the magnetic force on bound charges in the Lorentz oscillator model. The parameter ranges of incident radiation and the medium on which the magnetic field of the electromagnetic radiation will have a significant effect are traced using Floquet theory. The analysis reveals that the threshold intensity for a significant response of the magnetic field of the radiation at the second harmonic of the incident radiation can be reduced to {10}12 {{W}}{{cm}}-2 for off resonant and even lower for resonant interaction. This phenomenon has already been observed indirectly in experiments [1, 2]. Induced magnetizing current due to the magnetic force is shown to originate from a modified dielectric response, which may be useful in future magneto-optic devices, solar energy harvesting, and studying the ultrafast dynamics in doped dielectrics.

  6. Synchrotron radiation in strongly coupled conformal field theories

    CERN Document Server

    Athanasiou, Christiana; Liu, Hong; Nickel, Dominik; Rajagopal, Krishna

    2010-01-01

    Using gauge/gravity duality, we compute the energy density and angular distribution of the power radiated by a quark undergoing circular motion in strongly coupled ${\\cal N}=4$ supersymmetric Yang-Mills (SYM) theory. We compare the strong coupling results to those at weak coupling, finding them to be very similar. In both regimes, the angular distribution of the radiated power is in fact similar to that of synchrotron radiation produced by an electron in circular motion in classical electrodynamics: the quark emits radiation in a narrow beam along its velocity vector with a characteristic opening angle $\\alpha \\sim 1/\\gamma$. To an observer far away from the quark, the emitted radiation appears as a short periodic burst, just like the light from a lighthouse does to a ship at sea. Our strong coupling results are valid for any strongly coupled conformal field theory with a dual classical gravity description.

  7. IAEA programme in the field of radiation technology

    Science.gov (United States)

    Chmielewski, Andrzej G.; Haji-Saeid, Mohammad

    2005-07-01

    Radiation technologies applying gamma sources and electron accelerators for material modification are well-established processes. There are over 160 gamma industrial irradiators and 1300 electron industrial accelerators in operation worldwide. A new advancement in the field of radiation sources engineering is the development of high power direct e-/X conversion sources based on electron accelerators. Technologies to be developed beside environmental applications could be nanomaterials, structure engineered materials (sorbents, composites, ordered polymers, etc.) and natural polymers' processing. New products based on radiation-processed polysaccharides have already been commercialised in many countries of the East Asia and Pacific Region, especially in those being rich in natural polymers. Very important and promising applications concern environmental protection-radiation technology, being a clean and environment friendly process, helps to curb pollutants' emission as well. Industrial plants for flue gas treatment have been constructed in Poland and China. The pilot plant in Bulgaria using this technology has just started its operation. The Polish plant is equipped with accelerators of over 1 MW power, a breakthrough in radiation technology application. The industrial plant for wastewater treatment is under development in Korea and a pilot plant for sewage sludge irradiation has been in operation in India for many years. Due to recent developments, the Agency has restructured its programme and organized a Technical Meeting (TM) on "Emerging Applications of Radiation Technology for the 21st Century" at its Headquarters in Vienna, Austria, in April 2003, to review the present situation and possible developments of radiation technology to contribute to a sustainable development. This meeting provided the basic input to launch others in the most important fields of radiation technology applications: "Advances in Radiation Chemistry of Polymers" (Notre Dame, USA

  8. The Inhomogeneous Background of Hydrogen-Molecule Dissociating Radiation during Cosmic Reionization

    CERN Document Server

    Ahn, Kyungjin; Iliev, Ilian T; Mellema, Garrelt; Pen, Ue-Li

    2008-01-01

    The first, self-consistent calculations are presented of the cosmological, H2-dissociating UV background produced during the epoch of reionization by the sources of reionization. Large-scale radiative transfer simulations of reionization trace the impact of all the ionizing starlight on the IGM from all the sources in our simulation volume down to dwarf galaxies of mass ~10^8 Msun, identified by very high-resolution N-body simulations, including the self-regulating effect of IGM photoheating on dwarf galaxy formation. The UV continuum emitted below 13.6 eV by each source is then transferred through the same IGM, attenuated by atomic H Lyman series resonance lines, to predict the evolution of the inhomogeneous radiation background in the Lyman-Werner bands of H2 between 11 and 13.6 eV. On average, the intensity of this Lyman-Werner background is found to rise to the threshold level at which dissociation suppresses H2 cooling and star formation inside minihalos, long before reionization is complete. Spatial var...

  9. Modern Classical Electrodynamics and Electromagnetic Radiation - Vacuum Field Theory Aspects

    OpenAIRE

    2011-01-01

    The work is devoted to studying some new classical electrodynamics models of interacting charged point particles and related with them physical aspects. Based on the vacuum field theory no-geometry approach, developed in \\cite{BPT,BPT1}, the Lagrangian and Hamiltonian reformulations of some alternative classical electrodynamics models are devised. A problem closely related to the radiation reaction force is analyzed aiming to explain the Wheeler and Feynman reaction radiation mechanism, well ...

  10. The radiative transfer of synchrotron radiation through a compressed random magnetic field

    CERN Document Server

    Cawthorne, T V

    2014-01-01

    This paper examines the radiative transfer of synchrotron radiation in the presence of a magnetic field configuration resulting from the compression of a highly disordered magnetic field. It is shown that, provided Faraday rotation and circular polarization can be neglected, the radiative transfer equations for synchrotron radiation separate for this configuration, and the intensities and polarization values for sources that are uniform on large scales can be found straightforwardly in the case where opacity is significant. Although the emission and absorption coefficients must, in general, be obtained numerically, the process is much simpler than a full numerical solution to the transfer equations. Some illustrative results are given and an interesting effect, whereby the polarization increases while the magnetic field distribution becomes less strongly confined to the plane of compression, is discussed. The results are of importance for the interpretation of polarization near the edges of lobes in radio gal...

  11. Radiation hydrodynamics of triggered star formation: the effect of the diffuse radiation field

    CERN Document Server

    Haworth, Thomas J

    2011-01-01

    We investigate the effect of including diffuse field radiation when modelling the radiatively driven implosion of a Bonnor-Ebert sphere (BES). Radiation-hydrodynamical calculations are performed by using operator splitting to combine Monte Carlo photoionization with grid-based Eulerian hydrodynamics that includes self-gravity. It is found that the diffuse field has a significant effect on the nature of radiatively driven collapse which is strongly coupled to the strength of the driving shock that is established before impacting the BES. This can result in either slower or more rapid star formation than expected using the on-the-spot approximation depending on the distance of the BES from the source object. As well as directly compressing the BES, stronger shocks increase the thickness and density in the shell of accumulated material, which leads to short, strong, photo-evaporative ejections that reinforce the compression whenever it slows. This happens particularly effectively when the diffuse field is includ...

  12. Radiolysis of Serine in High Radiation Field

    Directory of Open Access Journals (Sweden)

    Ellen Y. Aguilar-Ovando

    2016-08-01

    Full Text Available The formation of amino acids under simulated condition suggests that this type of compounds were readily formed on the primitive Earth. Nevertheless, there is no conclusive explanation to the origin of their specific chirality in biological systems. Differences in their stability in the primitive conditions may give some clues about this unsolved problem. Protection mechanisms have been considered, such as the adsorption of the organic compounds onto mineral surfaces. By using HPLC/ELSD to analyze aqueous suspensions of serine adsorbed on clay (sodium montmorillonite and a meteorite (Allende irradiated in different doses with a cobalt-60 gamma source, the aim of this work was to study the possible protector role of these mineral surfaces when an amino acid, serine, is adsorbed onto them and the system is exposed to a high radiation source. The results showed that adsorption is better at acidic pH and desorption from the mineral at basic pH. The irradiation of the free amino acid destroyed it almost completely at a dose of 91 kGy, but the presence of the mineral abruptly decreases the d