WorldWideScience

Sample records for high energy bursts

  1. Spectra of gamma-ray bursts at high energies

    International Nuclear Information System (INIS)

    Matz, S.M.

    1986-01-01

    Between 1980 February and 1983 August the Gamma-Ray Spectrometer (GRS) on the Solar Maximum Mission satellite (SMM) observed 71 gamma-ray bursts. These events form a representative subset of the class of classical gamma-ray bursts. Since their discovery more than 15 years ago, hundreds of gamma-ray bursts have been detected; however, most observations have been limited to an energy range of roughly 30 keV-1 MeV. The large sensitive area and spectral range of the GRS allow, for the first time, an investigation of the high energy (>1 MeV) behavior of a substantial number of gamma-ray bursts. It is found that high-energy emission is seen in a large fraction of all events and that the data are consistent with all bursts emitting to at least 5 MeV with no cut-offs. Further, no burst spectrum measured by GRS has a clear high-energy cut-off. The high-energy emission can be a significant part of the total burst energy on the average about 30% of the observed energy above 30 keV is contained in the >1 MeV photons. The fact that the observations are consistent with the presence of high-energy emission in all events implies a limit on the preferential beaming of high-energy photons, from any mechanism. Single-photon pair-production in a strong magnetic field produces such beaming; assuming that the low-energy emission is isotropic, the data imply an upper limit of 1 x 10 12 G on the typical magnetic field at burst radiation sites

  2. Structural bursts produced by high energy muons in the rock

    International Nuclear Information System (INIS)

    Honda, K.; Takahashi, T.; Teramoto, Y.; Higashi, S.; Ozaki, S.

    1975-01-01

    Lateral structures of bursts produced by high energy muons in the rock have been observed at a depth 30 mw. e. underground by use of two layers of proportional counters. The running times were 7940 hr. The number of structural bursts observed, which have two cores in the both layers ( 1 >= 200, N 2 >= 20 particles) is 110, 1.6% of total events. These structural bursts have two types; 1) incident directions of two cores are parallel, 2) two cores intersect in the rock within 2 m above the roof of the tunnel. The events of this 2) type have large transverse momentum. (orig.) [de

  3. High energy particles from {gamma}-ray bursts

    Energy Technology Data Exchange (ETDEWEB)

    Waxman, E [Weizmann Institute of Science, Rehovot (Israel)

    2001-11-15

    A review is presented of the fireball model of {gamma}-ray bursts (GRBs), and of the production in GRB fireballs of high energy protons and neutrinos. Constraints imposed on the model by recent afterglow observations, which support the association of GRB and ultra-high energy cosmic-ray (UHECR) sources, are discussed. Predictions of the GRB model for UHECR production, which can be tested with planned large area UHECR detectors and with planned high energy neutrino telescopes, are reviewed. (author)

  4. High energy photons and neutrinos from gamma ray bursts

    International Nuclear Information System (INIS)

    Dar, A.

    1998-01-01

    The Hubble space telescope has recently discovered thousands of gigantic comet-like objects in a ring around the central star in the nearest planetary nebula. It is suggested that such circumstellar rings exist around most of stars. Collisions of the relativistic debris from gamma ray bursts in dense stellar regions with such gigantic comet-like objects, which have been stripped off from the circumstellar rings by gravitational perturbations, produce detectable fluxes of high energy gamma-rays and neutrinos from gamma ray bursts

  5. Detection of artifacts from high energy bursts in neonatal EEG.

    Science.gov (United States)

    Bhattacharyya, Sourya; Biswas, Arunava; Mukherjee, Jayanta; Majumdar, Arun Kumar; Majumdar, Bandana; Mukherjee, Suchandra; Singh, Arun Kumar

    2013-11-01

    Detection of non-cerebral activities or artifacts, intermixed within the background EEG, is essential to discard them from subsequent pattern analysis. The problem is much harder in neonatal EEG, where the background EEG contains spikes, waves, and rapid fluctuations in amplitude and frequency. Existing artifact detection methods are mostly limited to detect only a subset of artifacts such as ocular, muscle or power line artifacts. Few methods integrate different modules, each for detection of one specific category of artifact. Furthermore, most of the reference approaches are implemented and tested on adult EEG recordings. Direct application of those methods on neonatal EEG causes performance deterioration, due to greater pattern variation and inherent complexity. A method for detection of a wide range of artifact categories in neonatal EEG is thus required. At the same time, the method should be specific enough to preserve the background EEG information. The current study describes a feature based classification approach to detect both repetitive (generated from ECG, EMG, pulse, respiration, etc.) and transient (generated from eye blinking, eye movement, patient movement, etc.) artifacts. It focuses on artifact detection within high energy burst patterns, instead of detecting artifacts within the complete background EEG with wide pattern variation. The objective is to find true burst patterns, which can later be used to identify the Burst-Suppression (BS) pattern, which is commonly observed during newborn seizure. Such selective artifact detection is proven to be more sensitive to artifacts and specific to bursts, compared to the existing artifact detection approaches applied on the complete background EEG. Several time domain, frequency domain, statistical features, and features generated by wavelet decomposition are analyzed to model the proposed bi-classification between burst and artifact segments. A feature selection method is also applied to select the

  6. High-energy neutrinos from gamma ray bursts

    International Nuclear Information System (INIS)

    Dermer, Charles D.; Atoyan, Armen

    2003-01-01

    We treat high-energy neutrino production in gamma ray bursts (GRBs). Detailed calculations of photomeson neutrino production are presented for the collapsar model, where internal nonthermal synchrotron radiation is the primary target photon field, and the supranova model, where external pulsar-wind synchrotron radiation provides important additional target photons. Detection of > or approx. 10 TeV neutrinos from GRBs with Doppler factors > or approx. 200, inferred from γ-ray observations, would support the supranova model. Detection of or approx. 3x10 -4 erg cm -2 offer a realistic prospect for detection of ν μ

  7. The Prompt and High Energy Emission of Gamma Ray Bursts

    International Nuclear Information System (INIS)

    Meszaros, P.

    2009-01-01

    I discuss some recent developments concerning the prompt emission of gamma-ray bursts, in particular the jet properties and radiation mechanisms, as exemplified by the naked-eye burst GRB 080319b, and the prompt X-ray emission of XRB080109/SN2008d, where the progenitor has, for the first time, been shown to contribute to the prompt emission. I discuss then some recent theoretical calculations of the GeV/TeV spectrum of GRB in the context of both leptonic SSC models and hadronic models. The recent observations by the Fermi satellite of GRB 080916C are then reviewed, and their implications for such models are discussed, together with its interesting determination of a bulk Lorentz factor, and the highest lower limit on the quantum gravity energy scale so far.

  8. High-energy charged particle bursts in the near-Earth space as earthquake precursors

    Directory of Open Access Journals (Sweden)

    S. Yu. Aleksandrin

    2003-02-01

    Full Text Available The experimental data on high-energy charged particle fluxes, obtained in various near-Earth space experiments (MIR orbital station, METEOR-3, GAMMA and SAMPEX satellites were processed and analyzed with the goal to search for particle bursts. Particle bursts have been selected in every experiment considered. It was shown that the significant part of high-energy charged particle bursts correlates with seismic activity. Moreover, the particle bursts are observed several hours before strong earthquakes; L-shells of particle bursts and corresponding earthquakes are practically the same. Some features of a seismo-magnetosphere connection model, based on the interaction of electromagnetic emission of seismic origin and radiation belt particles, were considered. Key words. Ionospheric physics (energetic particles, trapped; energetic particles, precipitating; magnetosphere-ionosphere interactions

  9. High energy neutrinos from gamma-ray bursts with precursor supernovae.

    Science.gov (United States)

    Razzaque, Soebur; Mészáros, Peter; Waxman, Eli

    2003-06-20

    The high energy neutrino signature from proton-proton and photo-meson interactions in a supernova remnant shell ejected prior to a gamma-ray burst provides a test for the precursor supernova, or supranova, model of gamma-ray bursts. Protons in the supernova remnant shell and photons entrapped from a supernova explosion or a pulsar wind from a fast-rotating neutron star remnant provide ample targets for protons escaping the internal shocks of the gamma-ray burst to interact and produce high energy neutrinos. We calculate the expected neutrino fluxes, which can be detected by current and future experiments.

  10. Very high-energy gamma rays from gamma-ray bursts.

    Science.gov (United States)

    Chadwick, Paula M

    2007-05-15

    Very high-energy (VHE) gamma-ray astronomy has undergone a transformation in the last few years, with telescopes of unprecedented sensitivity having greatly expanded the source catalogue. Such progress makes the detection of a gamma-ray burst at the highest energies much more likely than previously. This paper describes the facilities currently operating and their chances for detecting gamma-ray bursts, and reviews predictions for VHE gamma-ray emission from gamma-ray bursts. Results to date are summarized.

  11. High-energy emission from gamma-ray bursts

    International Nuclear Information System (INIS)

    Nolan, P.L.; Share, G.H.; Matz, S.; Chupp, E.L.; Forrest, D.J.; Rieger, E.

    1984-01-01

    We discuss broad-band continuum spectroscopy of 17 gamma-ray bursts above 0.3 MeV. The spectra were fitted by 3 trial functions, none of which provided an adequate fit to all the spectra. Most were too hard for a thermal bremsstarhlung function. Harder functional forms, such as thermal synchrotron or power-law, provide better fits for most of the spectra. The strong emission observed above 1 MeV raises some interesting theoretical questions

  12. VERY HIGH ENERGY OBSERVATIONS OF GAMMA-RAY BURSTS WITH STACEE

    International Nuclear Information System (INIS)

    Jarvis, A.; Ong, R. A.; Ball, J.; Carson, J. E.; Zweerink, J.; Williams, D. A.; Aune, T.; Covault, C. E.; Driscoll, D. D.; Fortin, P.; Mukherjee, R.; Gingrich, D. M.; Hanna, D. S.; Kildea, J.; Lindner, T.; Mueller, C.; Ragan, K.

    2010-01-01

    Gamma-ray bursts (GRBs) are the most powerful explosions known in the universe. Sensitive measurements of the high-energy spectra of GRBs can place important constraints on the burst environments and radiation processes. Until recently, there were no observations during the first few minutes of GRB afterglows in the energy range between 30 GeV and ∼1 TeV. With the launch of the Swift GRB Explorer in late 2004, GRB alerts and localizations within seconds of the bursts became available. The Solar Tower Atmospheric Cherenkov Effect Experiment (STACEE) was a ground-based, gamma-ray telescope with an energy threshold of ∼150 GeV for sources at zenith. At the time of Swift's launch, STACEE was in a rare position to provide >150 GeV follow-up observations of GRBs as fast as three minutes after the burst alert. In addition, STACEE performed follow-up observations of several GRBs that were localized by the HETE-2 and INTEGRAL satellites. Between 2002 June and 2007 July, STACEE made follow-up observations of 23 GRBs. Upper limits are placed on the high-energy gamma-ray fluxes from 21 of these bursts.

  13. Constraining the High-Energy Emission from Gamma-Ray Bursts with Fermi

    Science.gov (United States)

    Gehrels, Neil; Harding, A. K.; Hays, E.; Racusin, J. L.; Sonbas, E.; Stamatikos, M.; Guirec, S.

    2012-01-01

    We examine 288 GRBs detected by the Fermi Gamma-ray Space Telescope's Gamma-ray Burst Monitor (GBM) that fell within the field-of-view of Fermi's Large Area Telescope (LAT) during the first 2.5 years of observations, which showed no evidence for emission above 100 MeV. We report the photon flux upper limits in the 0.1-10 GeV range during the prompt emission phase as well as for fixed 30 s and 100 s integrations starting from the trigger time for each burst. We compare these limits with the fluxes that would be expected from extrapolations of spectral fits presented in the first GBM spectral catalog and infer that roughly half of the GBM-detected bursts either require spectral breaks between the GBM and LAT energy bands or have intrinsically steeper spectra above the peak of the nuF(sub v) spectra (E(sub pk)). In order to distinguish between these two scenarios, we perform joint GBM and LAT spectral fits to the 30 brightest GBM-detected bursts and find that a majority of these bursts are indeed softer above E(sub pk) than would be inferred from fitting the GBM data alone. Approximately 20% of this spectroscopic subsample show statistically significant evidence for a cut-off in their high-energy spectra, which if assumed to be due to gamma gamma attenuation, places limits on the maximum Lorentz factor associated with the relativistic outflow producing this emission. All of these latter bursts have maximum Lorentz factor estimates that are well below the minimum Lorentz factors calculated for LAT-detected GRBs, revealing a wide distribution in the bulk Lorentz factor of GRB outflows and indicating that LAT-detected bursts may represent the high end of this distribution.

  14. NEUTRINO EMISSION FROM HIGH-ENERGY COMPONENT GAMMA-RAY BURSTS

    International Nuclear Information System (INIS)

    Becker, Julia K.; Olivo, Martino; Halzen, Francis; O Murchadha, Aongus

    2010-01-01

    Gamma-ray bursts (GRBs) have the potential to produce the particle energies (up to 10 21 eV) and energy budget (10 44 erg yr -1 Mpc -3 ) to accommodate the spectrum of the highest energy cosmic rays; on the other hand, there is no observational evidence that they accelerate hadrons. The Fermi Gamma-ray Space Telescope recently observed two bursts that exhibit a power-law high-energy extension of a typical (Band) photon spectrum that extends to ∼30 GeV. On the basis of fireball phenomenology we argue that these two bursts, along with GRB941017 observed by EGRET in 1994, show indirect evidence for considerable baryon loading. Since the detection of neutrinos is the only unambiguous way to establish that GRBs accelerate protons, we use two methods to estimate the neutrino flux produced when they interact with fireball photons to produce charged pions and neutrinos. While the number of events expected from the two Fermi bursts discussed is small, should GRBs be the sources of the observed cosmic rays, a GRB941017-like event that has a hadronic power-law tail extending to several tens of GeV will be detected by the IceCube neutrino telescope.

  15. A Search for High-Energy Counterparts to Fast Radio Bursts

    Science.gov (United States)

    Cunningham, Virginia A.; Cenko, Bradley

    2018-01-01

    We report on a search for high-energy counterparts to Fast Radio Bursts (FRBs) with the Fermi Gamma-ray Burst Monitor (GBM), Fermi Large Area Telescope (LAT), and the Swift Burst Alert Telescope (BAT). We find no significant associations for any of the 14 FRBs in our sample, but report upper limits to the high-energy fluence for each on timescales of ∼0.1, 1, 10, and 100 s. We report lower limits on the radio to high-energy fluence, fr / fγ, for timescales of ∼0.1 and 100 s. The non-detection of high-energy emission is expected if FRBs are analogous to the giant pulses seen from the Crab pulsar, but the observed radio fluences of FRBs are orders of magnitude larger than even the most extreme giant pulses would be at the implied cosmological distances. It has also been proposed that events similar to magnetar hyperflares produce FRBs; this might be a viable model, but our fr / fγ lower limits are in tension with the fr / fγ upper limit for the 2004 superburst of SGR 1806‑20, for 6 out of the 12 FRBs that we study. This demonstrates the utility of analyses of high-energy data for FRBs in tracking down the nature of these elusive sources.

  16. Bursts of the Crab Nebula gamma-ray emission at high and ultra-high energies

    Directory of Open Access Journals (Sweden)

    Lidvansky A.S.

    2017-01-01

    Full Text Available Characteristics of the flares of gamma rays detected from the Crab Nebula by the AGILE and Fermi-LAT satellite instruments are compared with those of a gamma ray burst recorded by several air shower arrays on February 23, 1989 and with one recent observation made by the ARGO-YBJ array. It is demonstrated that though pulsar-periodicity and energy spectra of emissions at 100 MeV (satellite gamma ray telescopes and 100 TeV (EAS arrays are different, their time structures seem to be similar. Moreover, maybe the difference between “flares” and “waves” recently found in the Crab Nebula emission by the AGILE team also exists at ultra-high energies.

  17. A possible very high energy gamma-ray burst from Hercules X-1

    International Nuclear Information System (INIS)

    Vishwanath, P.R.; Bhat, P.N.; Ramanamurthy, P.V.; Sreekantan, B.V.

    1989-01-01

    A large increase is observed in the trigger rate in the direction of Hercules X-1 in the Atmospheric Cerenkov array at Pachmarhi, India. The burst lasted from 2147 UT to 2201 UT on April 11, 1986. The accidental coincidence rate did not show any increase during the burst. Barring any electronic noise or celestial or terrestrial optical phenomenon with time structure similar to that of atmospheric Cerenkov phenomenon, the increase is ascribed to TeV gamma rays from Her X-1. The number of gamma-ray events during the burst amounted to about 54 percent of the cosmic-ray flux, resulting in a 42-sigma effect. This is the largest TeV gamma-ray signal seen from any source till now. The time-averaged flux for the burst period is 1.8 x 10 photons/sq cm per s above a threshold energy of 0.4 TeV, which results in a luminosity of 1.8 x 10 to the 37 ergs/s. The burst took place at the end of the 'high on' state in the 35-day cycle of the Her X-1 binary system indicating accretion disk as the possible production site. 14 refs

  18. High energy bursts from a solid state laser operated in the heat capacity limited regime

    Science.gov (United States)

    Albrecht, G.; George, E.V.; Krupke, W.F.; Sooy, W.; Sutton, S.B.

    1996-06-11

    High energy bursts are produced from a solid state laser operated in a heat capacity limited regime. Instead of cooling the laser, the active medium is thermally well isolated. As a result, the active medium will heat up until it reaches some maximum acceptable temperature. The waste heat is stored in the active medium itself. Therefore, the amount of energy the laser can put out during operation is proportional to its mass, the heat capacity of the active medium, and the temperature difference over which it is being operated. The high energy burst capacity of a heat capacity operated solid state laser, together with the absence of a heavy, power consuming steady state cooling system for the active medium, will make a variety of applications possible. Alternately, cooling takes place during a separate sequence when the laser is not operating. Industrial applications include new material working processes. 5 figs.

  19. High-energy photons and neutrinos from gamma-ray bursts

    International Nuclear Information System (INIS)

    Dar, A.

    1998-01-01

    The Hubble Space Telescope has recently discovered thousands of gigantic cometlike objects in a ring around the central star in the nearest planetary nebula. It is assumed that such circumstellar rings exist around the majority of stars. Collisions of relativistic debris from gamma-ray bursts (GRB) in dense stellar regions with such gigantic cometlike objects, which have been stripped off from the circumstellar rings by gravitational perturbations, produce detectable fluxes of high energy γ rays and neutrinos from GRBs

  20. Neutron stars as X-ray burst sources. II. Burst energy histograms and why they burst

    International Nuclear Information System (INIS)

    Baan, W.A.

    1979-01-01

    In this work we explore some of the implications of a model for X-ray burst sources where bursts are caused by Kruskal-Schwarzschild instabilities at the magnetopause of an accreting and rotating neutron star. A number of simplifying assumptions are made in order to test the model using observed burst-energy histograms for the rapid burster MXB 1730--335. The predicted histograms have a correct general shape, but it appears that other effects are important as well, and that mode competition, for instance, may suppress the histograms at high burst energies. An explanation is ventured for the enhancement in the histogram at the highest burst energies, which produces the bimodal shape in high accretion rate histograms. Quantitative criteria are given for deciding when accreting neutron stars are steady sources or burst sources, and these criteria are tested using the X-ray pulsars

  1. THE HIGH ENERGY BUDGET ALLOCATIONS IN SHOCKS AND GAMMA RAY BURSTS

    International Nuclear Information System (INIS)

    Eichler, David; Guetta, Dafne; Pohl, Martin

    2010-01-01

    The statistical distribution of energies among particles responsible for long gamma-ray burst (GRB) emission is analyzed in light of recent results of the Fermi Observatory. The all-sky flux, F γ , recorded by the Gamma-Ray Burst Monitor (GBM) is shown, despite its larger energy range, to be not significantly larger than that reported by the Burst and Transient Explorer, suggesting a relatively small flux in the 3-30 MeV energy range. The present-day energy input rate in γ-rays recorded by the GBM from long GRBs is found, assuming star formation rates in the literature, to be W-dot(0)=0.5 F γ H/c=5x10 42 erg Mpc -3 yr -1 . The Large Area Telescope fluence, when observed, is about 5%-10% per decade of the total, in good agreement with the predictions of saturated, nonlinear shock acceleration. The high-energy component of long GRBs, as measured by Fermi, is found to contain only ∼10 -2.5 of the energy needed to produce ultrahigh-energy cosmic rays (UHECRs) above 4 EeV, assuming the latter to be extragalactic, when various numerical factors are carefully included, if the cosmic-ray source spectrum has a spectral index of -2. The observed γ-ray fraction of the required UHECR energy is even smaller if the source spectrum is softer than E -2 . The AMANDA II limits rule out such a GRB origin for UHECRs if much more than 10 -2 of the cosmic-ray energy goes into neutrinos that are within, and simultaneous with, the γ-ray beam. It is suggested that 'orphan' neutrinos out of the γ-ray beam might be identifiable via orphan afterglow or other wide angle signatures of GRBs in lieu of coincidence with prompt γ-rays, and it is recommended that feasible single neutrino trigger criteria be established to search for such coincidences.

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

    International Nuclear Information System (INIS)

    Baerwald, Philipp

    2014-07-01

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

  3. Stacked search for time shifted high energy neutrinos from gamma ray bursts with the Antares neutrino telescope

    International Nuclear Information System (INIS)

    Adrian-Martinez, S.; Ardid, M.; Felis, I.; Martinez-Mora, J.A.; Saldana, M.; Albert, A.; Drouhin, D.; Racca, C.; Andre, M.; Anghinolfi, M.; Anton, G.; Eberl, T.; Enzenhoefer, A.; Fehn, K.; Folger, F.; Geisselsoeder, S.; Geyer, K.; Gleixner, A.; Graf, K.; Hallmann, S.; Hoessl, J.; Hofestaedt, J.; James, C.W.; Kalekin, O.; Katz, U.; Kiessling, D.; Lahmann, R.; Richter, R.; Roensch, K.; Schmid, J.; Schnabel, J.; Seitz, T.; Sieger, C.; Tselengidou, M.; Wagner, S.; Aubert, J.J.; Bertin, V.; Brunner, J.; Busto, J.; Carr, J.; Costantini, H.; Coyle, P.; Dornic, D.; Mathieu, A.; Vallee, C.; Baret, B.; Barrios-Marti, J.; Hernandez-Rey, J.J.; Sanchez-Losa, A.; Toennis, C.; Zornoza, J.D.; Zuniga, J.; Basa, S.; Marcelin, M.; Nezri, E.; Biagi, S.; Coniglione, R.; Distefano, C.; Piattelli, P.; Riccobene, G.; Sapienza, P.; Trovato, A.; Bormuth, R.; Jong, M. de; Samtleben, D.F.E.; Bouwhuis, M.C.; Heijboer, A.J.; Michael, T.; Steijger, J.J.M.; Visser, E.; Bruijn, R.; Capone, A.; De Bonis, G.; Fermani, P.; Perrina, C.; Caramete, L.; Pavalas, G.E.; Popa, V.; Chiarusi, T.; Circella, M.; Creusot, A.; Galata, S.; Gracia-Ruiz, R.; Van Elewyck, V.; Dekeyser, I.; Lefevre, D.; Tamburini, C.; Deschamps, A.; Hello, Y.; Donzaud, C.; Dumas, A.; Gay, P.; Elsaesser, D.; Kadler, M.; Kreter, M.; Mueller, C.; Fusco, L.A.; Margiotta, A.; Pellegrino, C.; Spurio, M.; Giordano, V.; Haren, H. van; Hugon, C.; Taiuti, M.; Kooijman, P.; Kouchner, A.; Kreykenbohm, I.; Wilms, J.; Kulikovskiy, V.; Leonora, E.; Loucatos, S.; Marinelli, A.; Migliozzi, P.; Moussa, A.; Pradier, T.; Sanguineti, M.; Schuessler, F.; Stolarczyk, T.; Vallage, B.; Vivolo, D.

    2017-01-01

    A search for high-energy neutrino emission correlated with gamma-ray bursts outside the electromagnetic prompt-emission time window is presented. Using a stacking approach of the time delays between reported gamma-ray burst alerts and spatially coincident muon-neutrino signatures, data from the Antares neutrino telescope recorded between 2007 and 2012 are analysed. One year of public data from the IceCube detector between 2008 and 2009 have been also investigated. The respective timing profiles are scanned for statistically significant accumulations within 40 days of the Gamma Ray Burst, as expected from Lorentz Invariance Violation effects and some astrophysical models. No significant excess over the expected accidental coincidence rate could be found in either of the two data sets. The average strength of the neutrino signal is found to be fainter than one detectable neutrino signal per hundred gamma-ray bursts in the Antares data at 90% confidence level. (orig.)

  4. Stacked search for time shifted high energy neutrinos from gamma ray bursts with the Antares neutrino telescope

    Energy Technology Data Exchange (ETDEWEB)

    Adrian-Martinez, S.; Ardid, M.; Felis, I.; Martinez-Mora, J.A.; Saldana, M. [Universitat Politecnica de Valencia, Institut d' Investigacio per a la Gestio Integrada de les Zones Costaneres (IGIC), Gandia (Spain); Albert, A.; Drouhin, D.; Racca, C. [GRPHE-Institut Universitaire de Technologie de Colmar, 34 rue du Grillenbreit, BP 50568, Colmar (France); Andre, M. [Technical University of Catalonia, Laboratory of Applied Bioacoustics, Vilanova i la Geltru, Barcelona (Spain); Anghinolfi, M. [INFN-Sezione di Genova, Genoa (Italy); Anton, G.; Eberl, T.; Enzenhoefer, A.; Fehn, K.; Folger, F.; Geisselsoeder, S.; Geyer, K.; Gleixner, A.; Graf, K.; Hallmann, S.; Hoessl, J.; Hofestaedt, J.; James, C.W.; Kalekin, O.; Katz, U.; Kiessling, D.; Lahmann, R.; Richter, R.; Roensch, K.; Schmid, J.; Schnabel, J.; Seitz, T.; Sieger, C.; Tselengidou, M.; Wagner, S. [Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Erlangen Centre for Astroparticle Physics, Erlangen (Germany); Aubert, J.J.; Bertin, V.; Brunner, J.; Busto, J.; Carr, J.; Costantini, H.; Coyle, P.; Dornic, D.; Mathieu, A.; Vallee, C. [CPPM, Aix-Marseille Universite, CNRS/IN2P3, Marseille (France); Baret, B.; Barrios-Marti, J.; Hernandez-Rey, J.J.; Sanchez-Losa, A.; Toennis, C.; Zornoza, J.D.; Zuniga, J. [CSIC-Universitat de Valencia, IFIC-Instituto de Fisica Corpuscular, Edificios Investigacion de Paterna, Paterna, Valencia (Spain); Basa, S.; Marcelin, M.; Nezri, E. [Pole de l' Etoile Site de Chateau-Gombert, LAM-Laboratoire d' Astrophysique de Marseille, Marseille Cedex 13 (France); Biagi, S.; Coniglione, R.; Distefano, C.; Piattelli, P.; Riccobene, G.; Sapienza, P.; Trovato, A. [INFN-Laboratori Nazionali del Sud (LNS), Catania (Italy); Bormuth, R.; Jong, M. de; Samtleben, D.F.E. [Nikhef, Science Park, Amsterdam (Netherlands); Universiteit Leiden, Leids Instituut voor Onderzoek in Natuurkunde, Leiden (Netherlands); Bouwhuis, M.C.; Heijboer, A.J.; Michael, T.; Steijger, J.J.M.; Visser, E. [Nikhef, Science Park, Amsterdam (Netherlands); Bruijn, R. [Nikhef, Science Park, Amsterdam (Netherlands); Universiteit van Amsterdam, Instituut voor Hoge-Energie Fysica, Amsterdam (Netherlands); Capone, A.; De Bonis, G.; Fermani, P.; Perrina, C. [INFN-Sezione di Roma, Rome (Italy); Dipartimento di Fisica dell' Universita La Sapienza, Rome (Italy); Caramete, L.; Pavalas, G.E.; Popa, V. [Institute for Space Sciences, Bucharest, Magurele (Romania); Chiarusi, T. [INFN-Sezione di Bologna, Bologna (Italy); Circella, M. [INFN-Sezione di Bari, Bari (Italy); Creusot, A.; Galata, S.; Gracia-Ruiz, R.; Van Elewyck, V. [APC, Universite Paris Diderot, CNRS/IN2P3, CEA/IRFU, Observatoire de Paris, Sorbonne Paris Cite, Paris (France); Dekeyser, I.; Lefevre, D.; Tamburini, C. [Aix-Marseille University, Mediterranean Institute of Oceanography (MIO), Marseille Cedex 9 (France); Universite du Sud Toulon-Var, CNRS-INSU/IRD UM 110, La Garde Cedex (France); Deschamps, A.; Hello, Y. [Geoazur, Universite Nice Sophia-Antipolis, CNRS/INSU, IRD, Observatoire de la Cote d' Azur, Sophia Antipolis (France); Donzaud, C. [APC, Universite Paris Diderot, CNRS/IN2P3, CEA/IRFU, Observatoire de Paris, Sorbonne Paris Cite, Paris (France); Universite Paris-Sud, Orsay Cedex (France); Dumas, A.; Gay, P. [Clermont Universite, Universite Blaise Pascal, CNRS/IN2P3, Laboratoire de Physique Corpusculaire, BP 10448, Clermont-Ferrand (France); Elsaesser, D.; Kadler, M.; Kreter, M.; Mueller, C. [Universitaet Wuerzburg, Institut fuer Theoretische Physik und Astrophysik, Wuerzburg (Germany); Fusco, L.A.; Margiotta, A.; Pellegrino, C.; Spurio, M. [INFN-Sezione di Bologna, Bologna (Italy); Dipartimento di Fisica dell' Universita, Bologna (Italy); Giordano, V. [INFN-Sezione di Catania, Catania (Italy); Haren, H. van [Royal Netherlands Institute for Sea Research (NIOZ), ' t Horntje, Texel (Netherlands); Hugon, C.; Taiuti, M. [INFN-Sezione di Genova, Genoa (Italy); Dipartimento di Fisica dell' Universita, Genoa (Italy); Kooijman, P. [Nikhef, Science Park, Amsterdam (Netherlands); Universiteit Utrecht, Faculteit Betawetenschappen, Utrecht (Netherlands); Universiteit van Amsterdam, Instituut voor Hoge-Energie Fysica, Amsterdam (Netherlands); Kouchner, A. [APC, Universite Paris Diderot, CNRS/IN2P3, CEA/IRFU, Observatoire de Paris, Sorbonne Paris Cite, Paris (France); Institut Universitaire de France, Paris (France); Kreykenbohm, I.; Wilms, J. [Universitaet Erlangen-Nuernberg, Dr. Remeis-Sternwarte and ECAP, Bamberg (Germany); Kulikovskiy, V. [INFN-Laboratori Nazionali del Sud (LNS), Catania (Italy); Moscow State University, Skobeltsyn Institute of Nuclear Physics, Moscow (Russian Federation); Leonora, E. [INFN-Sezione di Catania, Catania (Italy); Dipartimento di Fisica ed Astronomia dell' Universita, Catania (Italy); Loucatos, S. [APC, Universite Paris Diderot, CNRS/IN2P3, CEA/IRFU, Observatoire de Paris, Sorbonne Paris Cite, Paris (France); CEA Saclay, Direction des Sciences de la Matiere, Institut de recherche sur les lois fondamentales de l' Univers, Service de Physique des Particules, Gif-sur-Yvette Cedex (France); Marinelli, A. [INFN-Sezione di Pisa, Pisa (Italy); Dipartimento di Fisica dell' Universita, Pisa (Italy); Migliozzi, P. [INFN-Sezione di Napoli, Naples (IT); Moussa, A. [University Mohammed I, Laboratory of Physics of Matter and Radiations, Oujda (MA); Pradier, T. [Universite de Strasbourg et CNRS/IN2P3, IPHC-Institut Pluridisciplinaire Hubert Curien, 23 rue du Loess, BP 28, Strasbourg Cedex 2 (FR); Sanguineti, M. [Dipartimento di Fisica dell' Universita, Genoa (IT); Schuessler, F.; Stolarczyk, T.; Vallage, B. [CEA Saclay, Direction des Sciences de la Matiere, Institut de recherche sur les lois fondamentales de l' Univers, Service de Physique des Particules, Gif-sur-Yvette Cedex (FR); Vivolo, D. [INFN-Sezione di Napoli, Naples (IT); Dipartimento di Fisica dell' Universita Federico II di Napoli, Naples (IT)

    2017-01-15

    A search for high-energy neutrino emission correlated with gamma-ray bursts outside the electromagnetic prompt-emission time window is presented. Using a stacking approach of the time delays between reported gamma-ray burst alerts and spatially coincident muon-neutrino signatures, data from the Antares neutrino telescope recorded between 2007 and 2012 are analysed. One year of public data from the IceCube detector between 2008 and 2009 have been also investigated. The respective timing profiles are scanned for statistically significant accumulations within 40 days of the Gamma Ray Burst, as expected from Lorentz Invariance Violation effects and some astrophysical models. No significant excess over the expected accidental coincidence rate could be found in either of the two data sets. The average strength of the neutrino signal is found to be fainter than one detectable neutrino signal per hundred gamma-ray bursts in the Antares data at 90% confidence level. (orig.)

  5. Limits to the Fraction of High-energy Photon Emitting Gamma-Ray Bursts

    Science.gov (United States)

    Akerlof, Carl W.; Zheng, WeiKang

    2013-02-01

    After almost four years of operation, the two instruments on board the Fermi Gamma-ray Space Telescope have shown that the number of gamma-ray bursts (GRBs) with high-energy photon emission above 100 MeV cannot exceed roughly 9% of the total number of all such events, at least at the present detection limits. In a recent paper, we found that GRBs with photons detected in the Large Area Telescope have a surprisingly broad distribution with respect to the observed event photon number. Extrapolation of our empirical fit to numbers of photons below our previous detection limit suggests that the overall rate of such low flux events could be estimated by standard image co-adding techniques. In this case, we have taken advantage of the excellent angular resolution of the Swift mission to provide accurate reference points for 79 GRB events which have eluded any previous correlations with high-energy photons. We find a small but significant signal in the co-added field. Guided by the extrapolated power-law fit previously obtained for the number distribution of GRBs with higher fluxes, the data suggest that only a small fraction of GRBs are sources of high-energy photons.

  6. LIMITS TO THE FRACTION OF HIGH-ENERGY PHOTON EMITTING GAMMA-RAY BURSTS

    International Nuclear Information System (INIS)

    Akerlof, Carl W.; Zheng, WeiKang

    2013-01-01

    After almost four years of operation, the two instruments on board the Fermi Gamma-ray Space Telescope have shown that the number of gamma-ray bursts (GRBs) with high-energy photon emission above 100 MeV cannot exceed roughly 9% of the total number of all such events, at least at the present detection limits. In a recent paper, we found that GRBs with photons detected in the Large Area Telescope have a surprisingly broad distribution with respect to the observed event photon number. Extrapolation of our empirical fit to numbers of photons below our previous detection limit suggests that the overall rate of such low flux events could be estimated by standard image co-adding techniques. In this case, we have taken advantage of the excellent angular resolution of the Swift mission to provide accurate reference points for 79 GRB events which have eluded any previous correlations with high-energy photons. We find a small but significant signal in the co-added field. Guided by the extrapolated power-law fit previously obtained for the number distribution of GRBs with higher fluxes, the data suggest that only a small fraction of GRBs are sources of high-energy photons.

  7. Solution High-Energy Burst Assembly (SHEBA) results from subprompt critical experiments with uranyl fluoride fuel

    International Nuclear Information System (INIS)

    Cappiello, C.C.; Butterfield, K.B.; Sanchez, R.G.

    1997-10-01

    The Solution High-Energy Burst Assembly (SHEBA) was originally constructed during 1980 and was designed to be a clean free-field geometry, right-circular, cylindrically symmetric critical assembly employing U(5%)O 2 F 2 solution as fuel. A second version of SHEBA, employing the same fuel but equipped with a fuel pump and shielding pit, was commissioned in 1993. This report includes data and operating experience for the 1993 SHEBA only. Solution-fueled benchmark work focused on the development of experimental measurements of the characterization of SHEBA; a summary of the results are given. A description of the system and the experimental results are given in some detail in the report. Experiments were designed to: (1) study the behavior of nuclear excursions in a low-enrichment solution, (2) evaluate accidental criticality alarm detectors for fuel-processing facilities, (3) provide radiation spectra and dose measurements to benchmark radiation transport calculations on a low-enrichment solution system similar to centrifuge enrichment plants, and (4) provide radiation fields to calibrate personnel dosimetry. 15 refs., 37 figs., 10 tabs

  8. High-energy emission from bright gamma-ray bursts using Fermi

    Energy Technology Data Exchange (ETDEWEB)

    Bissaldi, Elisabetta

    2010-05-25

    Among the scientific objectives of one of the present NASA missions, the Fermi Gamma-ray Space Telescope (FGST), is the study of gamma-ray bursts (GRBs). Fermi's payload comprises two science instruments, the Large Area Telescope (LAT) and the Gamma-Ray Burst Monitor (GBM). GBM was designed to detect and localize bursts for the Fermi mission. By means of an array of 12 NaI(Tl) (8 keV to 1 MeV) and two BGO (0.2 to 40 MeV) scintillation detectors, GBM extends the energy range (20 MeV to > 300 GeV) of the LAT instrument into the traditional range of current GRB databases. The physical detector response of the GBM instrument to GRBs has been determined with the help of Monte Carlo simulations, which are supported and verified by on-ground individual detector calibration measurements. The GBM detectors have been calibrated from 10 keV to 17.5 MeV using various gamma sources, and the detector response has been derived by simulations over the entire energy range (8 keV to 40 MeV) using GEANT. The GBM instrument has been operating successfully in orbit since June 11, 2008. The total trigger count from the time GBM triggering was enabled in July 2008 through December 2009 is 655, and about 380 of these triggers were classified as GRBs. Moreover, GBM detected several bursts in common with the LAT. These amazing detections mainly fulfill the primary science goal of GBM, which is the joint analysis of spectra and time histories of GRBs observed by both Fermi instruments. For every trigger, GBM provides near-real time on-board burst locations to permit repointing of the spacecraft and to obtain LAT observations of delayed emission from bursts. GBM and LAT refined locations are rapidly disseminated to the scientific community, often permitting extensive multiwavelength follow-up observations by NASA's Swift mission or other space- based observatories, and by numerous ground-based telescopes, thus allowing redshift determinations. Calculations of LAT upper limits are

  9. High-energy emission from bright gamma-ray bursts using Fermi

    International Nuclear Information System (INIS)

    Bissaldi, Elisabetta

    2010-01-01

    Among the scientific objectives of one of the present NASA missions, the Fermi Gamma-ray Space Telescope (FGST), is the study of gamma-ray bursts (GRBs). Fermi's payload comprises two science instruments, the Large Area Telescope (LAT) and the Gamma-Ray Burst Monitor (GBM). GBM was designed to detect and localize bursts for the Fermi mission. By means of an array of 12 NaI(Tl) (8 keV to 1 MeV) and two BGO (0.2 to 40 MeV) scintillation detectors, GBM extends the energy range (20 MeV to > 300 GeV) of the LAT instrument into the traditional range of current GRB databases. The physical detector response of the GBM instrument to GRBs has been determined with the help of Monte Carlo simulations, which are supported and verified by on-ground individual detector calibration measurements. The GBM detectors have been calibrated from 10 keV to 17.5 MeV using various gamma sources, and the detector response has been derived by simulations over the entire energy range (8 keV to 40 MeV) using GEANT. The GBM instrument has been operating successfully in orbit since June 11, 2008. The total trigger count from the time GBM triggering was enabled in July 2008 through December 2009 is 655, and about 380 of these triggers were classified as GRBs. Moreover, GBM detected several bursts in common with the LAT. These amazing detections mainly fulfill the primary science goal of GBM, which is the joint analysis of spectra and time histories of GRBs observed by both Fermi instruments. For every trigger, GBM provides near-real time on-board burst locations to permit repointing of the spacecraft and to obtain LAT observations of delayed emission from bursts. GBM and LAT refined locations are rapidly disseminated to the scientific community, often permitting extensive multiwavelength follow-up observations by NASA's Swift mission or other space- based observatories, and by numerous ground-based telescopes, thus allowing redshift determinations. Calculations of LAT upper limits are mainly based

  10. Burst of energy

    Science.gov (United States)

    The Discovery Center of Idaho (DCI) was the recipient of a grant from US DOE's Museum Science Education Program to build six permanent energy related exhibits to provide the public with hands-on experience with energy issues. Because of its volunteer support system, DC was able to build eleven exhibits. These exhibits are described and photographs are included. The signs used for the exhibits are reproduced as well as the materials used to advertise them to the public. Examples of DCI's newsletter are included that mention the new exhibits.

  11. Burst of Energy

    Energy Technology Data Exchange (ETDEWEB)

    1992-01-01

    The Discovery Center of Idaho (DCI) was the recipient of a grant from US DOE's Museum Science Education Program to build six permanent energy related exhibits to provide the public with hands-on experience with energy issues. Because of its volunteer support system, DC was able to build eleven exhibits. These exhibits are described and photographs are included. The signs used for the exhibits are reproduced as well as the materials used to advertise them to the public. Examples of DCI's newsletter are included that mention the new exhibits.

  12. High energy, single frequency, tunable laser source operating in burst mode for space based lidar applications

    Science.gov (United States)

    Cosentino, Alberto; Mondello, Alessia; Sapia, Adalberto; D'Ottavi, Alessandro; Brotini, Mauro; Gironi, Gianna; Suetta, Enrico

    2017-11-01

    This paper describes energetic, spatial, temporal and spectral characterization measurements of the Engineering Qualification Model (EQM) of the Laser Transmitter Assembly (TXA) used in the ALADIN instrument currently under development for the ESA ADM-AEOLUS mission (EADS Astrium as prime contractor for the satellite and the instrument). The EQM is equivalent to the Flight Model, with the exception of some engineering grade components. The Laser Transmitter Assembly, based on a diode pumped tripled Nd:YAG laser, is used to generate laser pulses at a nominal wavelength of 355 nm. This laser is operated in burst mode, with a pulse repetition cycle of 100 Hz during bursts. It is capable to operate in Single Longitudinal Mode and to be tuned over 25 GHz range. An internal "network" of sensors has been implemented inside the laser architecture to allow "in flight" monitoring of transmitter. Energy in excess of 100 mJ, with a spatial beam quality factor (M2) lower than 3, a spectral linewidth less than 50 MHz with a frequency stability better than 4 MHz on short term period have been measured on the EQM. Most of the obtained results are well within the expected values and match the Instrument requirements. They constitute an important achievement, showing the absence of major critical areas in terms of performance and the capability to obtain them in a rugged and compact structure suitable for space applications. The EQM will be submitted in the near future to an Environmental test campaign.

  13. A gamma-ray burst with a high-energy spectral component inconsistent with the synchrotron shock model.

    Science.gov (United States)

    González, M M; Dingus, B L; Kaneko, Y; Preece, R D; Dermer, C D; Briggs, M S

    2003-08-14

    Gamma-ray bursts are among the most powerful events in nature. These events release most of their energy as photons with energies in the range from 30 keV to a few MeV, with a smaller fraction of the energy radiated in radio, optical, and soft X-ray afterglows. The data are in general agreement with a relativistic shock model, where the prompt and afterglow emissions correspond to synchrotron radiation from shock-accelerated electrons. Here we report an observation of a high-energy (multi-MeV) spectral component in the burst of 17 October 1994 that is distinct from the previously observed lower-energy gamma-ray component. The flux of the high-energy component decays more slowly and its fluence is greater than the lower-energy component; it is described by a power law of differential photon number index approximately -1 up to about 200 MeV. This observation is difficult to explain with the standard synchrotron shock model, suggesting the presence of new phenomena such as a different non-thermal electron process, or the interaction of relativistic protons with photons at the source.

  14. High-energy Neutrino Emission from Short Gamma-Ray Bursts: Prospects for Coincident Detection with Gravitational Waves

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, Shigeo S.; Murase, Kohta; Mészáros, Peter [Department of Physics, Pennsylvania State University, University Park, PA 16802 (United States); Kiuchi, Kenta [Center for Gravitational Physics, Yukawa Institute for Theoretical Physics, Kyoto, Kyoto 606-8502 (Japan)

    2017-10-10

    We investigate current and future prospects for coincident detection of high-energy neutrinos and gravitational waves (GWs). Short gamma-ray bursts (SGRBs) are believed to originate from mergers of compact star binaries involving neutron stars. We estimate high-energy neutrino fluences from prompt emission, extended emission (EE), X-ray flares, and plateau emission, and we show that neutrino signals associated with the EE are the most promising. Assuming that the cosmic-ray loading factor is ∼10 and the Lorentz factor distribution is lognormal, we calculate the probability of neutrino detection from EE by current and future neutrino detectors, and we find that the quasi-simultaneous detection of high-energy neutrinos, gamma-rays, and GWs is possible with future instruments or even with current instruments for nearby SGRBs having EE. We also discuss stacking analyses that will also be useful with future experiments such as IceCube-Gen2.

  15. Variability in fluence and spectrum of high-energy photon bursts produced by lightning leaders

    OpenAIRE

    Celestin , Sebastien; Xu , Wei; Pasko , Victor P.

    2015-01-01

    International audience; In this paper, we model the production and acceleration of thermal runaway electrons during negative corona flash stages of stepping lightning leaders and the corresponding terrestrial gamma ray flashes (TGFs) or negative cloud-to-ground (−CG) lightning-produced X-ray bursts in a unified fashion. We show how the source photon spectrum and fluence depend on the potential drop formed in the lightning leader tip region during corona flash and how the X-ray burst spectrum ...

  16. A serach for moderate- and high-energy neturino emission correlated with gamma-ray bursts

    Science.gov (United States)

    Becker-Szendy, R.; Bratton, C. B.; Breault, J.; Casper, D.; Dye, S. T.; Gajewski, W.; Goldhaber, M.; Haines, T. J.; Halverson, P. G.; Kielczewska, D.

    1995-01-01

    A temporal correlation analysis between moderate- (60 Mev less than or equal to E(sub nu)greater than or equal to 2500 MeV) and high-energy (E(sub nu) greater than or equal to 2000 MeV) neutrino interactions consist of two types: the moderate-energy interactions that are contained within the volume of IMB-3 and the upward-going muons produced by high-energy nu(sub mu) interactions in the rock around the detector. No evidence is found for moderate- or high-energy neutrino emission from GRBs nor for any neutrino/neutrino correlation. The nonobservation of nu/GRB correlations allows upper limits to be placed on the neutrino flux associated with GRBs.

  17. NEW FERMI-LAT EVENT RECONSTRUCTION REVEALS MORE HIGH-ENERGY GAMMA RAYS FROM GAMMA-RAY BURSTS

    Energy Technology Data Exchange (ETDEWEB)

    Atwood, W. B. [Santa Cruz Institute for Particle Physics, Department of Physics and Department of Astronomy and Astrophysics, University of California at Santa Cruz, Santa Cruz, CA 95064 (United States); Baldini, L. [Universita di Pisa and Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa (Italy); Bregeon, J.; Pesce-Rollins, M.; Sgro, C.; Tinivella, M. [Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa (Italy); Bruel, P. [Laboratoire Leprince-Ringuet, Ecole polytechnique, CNRS/IN2P3, Palaiseau (France); Chekhtman, A. [Center for Earth Observing and Space Research, College of Science, George Mason University, Fairfax, VA 22030 (United States); Cohen-Tanugi, J. [Laboratoire Univers et Particules de Montpellier, Universite Montpellier 2, CNRS/IN2P3, F-34095 Montpellier (France); Drlica-Wagner, A.; Omodei, N.; Rochester, L. S.; Usher, T. L. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Granot, J. [Department of Natural Sciences, The Open University of Israel, 1 University Road, P.O. Box 808, Ra' anana 43537 (Israel); Longo, F. [Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, I-34127 Trieste (Italy); Razzaque, S. [Department of Physics, University of Johannesburg, Auckland Park 2006 (South Africa); Zimmer, S., E-mail: melissa.pesce.rollins@pi.infn.it, E-mail: nicola.omodei@stanford.edu, E-mail: granot@openu.ac.il [Department of Physics, Stockholm University, AlbaNova, SE-106 91 Stockholm (Sweden)

    2013-09-01

    Based on the experience gained during the four and a half years of the mission, the Fermi-LAT Collaboration has undertaken a comprehensive revision of the event-level analysis going under the name of Pass 8. Although it is not yet finalized, we can test the improvements in the new event reconstruction with the special case of the prompt phase of bright gamma-ray bursts (GRBs), where the signal-to-noise ratio is large enough that loose selection cuts are sufficient to identify gamma rays associated with the source. Using the new event reconstruction, we have re-analyzed 10 GRBs previously detected by the Large Area Telescope (LAT) for which an X-ray/optical follow-up was possible and found four new gamma rays with energies greater than 10 GeV in addition to the seven previously known. Among these four is a 27.4 GeV gamma ray from GRB 080916C, which has a redshift of 4.35, thus making it the gamma ray with the highest intrinsic energy ({approx}147 GeV) detected from a GRB. We present here the salient aspects of the new event reconstruction and discuss the scientific implications of these new high-energy gamma rays, such as constraining extragalactic background light models, Lorentz invariance violation tests, the prompt emission mechanism, and the bulk Lorentz factor of the emitting region.

  18. High energy, single frequency, tunable laser source operating in burst mode for space based lidar applications

    Science.gov (United States)

    Cosentino, Alberto; Mondello, Alessia; Sapia, Adalberto; D'Ottavi, Alessandro; Brotini, Mauro; Nava, Enzo; Stucchi, Emanuele; Trespidi, Franco; Mariottini, Cristina; Wazen, Paul; Falletto, Nicolas; Fruit, Michel

    2017-11-01

    This paper describes the laser transmitter assembly used in the ALADIN instrument currently in C/D development phase for the ESA ADM-AEOLUS mission (EADS Astrium as prime contractor for the satellite and the instrument). The Laser Transmitter Assembly (TXA), based on a diode pumped tripled Nd:YAG laser, is used to generate tunable laser pulses of 150 mJ at a nominal wavelength of 355 nm. This laser is operated in burst mode, with a pulse repetition cycle of 100 Hz. The TXA is composed of the following units: a diodepumped CW Nd:YAG Laser named Reference Laser Head (RLH), used to inject a diode-pumped, Q-switched, amplified and frequency tripled Nd:YAG Laser working in the third harmonic referred as Power Laser Head (PLH) and a Transmitter Laser Electronics (TLE) containing all the control and power electronics needed for PLH and RLH operation. The TXA is made by an European consortium under the leadership of Galileo Avionica (It), and including CESI (It), Quantel (Fr), TESAT (Ge) and Thales (Fr).

  19. Model-dependent estimate on the connection between fast radio bursts and ultra high energy cosmic rays

    International Nuclear Information System (INIS)

    Li, Xiang; Zhou, Bei; He, Hao-Ning; Fan, Yi-Zhong; Wei, Da-Ming

    2014-01-01

    The existence of fast radio bursts (FRBs), a new type of extragalatic transient, has recently been established, and quite a few models have been proposed. In this work, we discuss the possible connection between the FRB sources and ultra high energy (>10 18 eV) cosmic rays. We show that in the blitzar model and the model of merging binary neutron stars, which includes the huge energy release of each FRB central engine together with the rather high rate of FRBs, the accelerated EeV cosmic rays may contribute significantly to the observed ones. In other FRB models, including, for example, the merger of double white dwarfs and the energetic magnetar radio flares, no significant EeV cosmic ray is expected. We also suggest that the mergers of double neutron stars, even if they are irrelevant to FRBs, may play a nonignorable role in producing EeV cosmic ray protons if supramassive neutron stars are formed in a sufficient fraction of mergers and the merger rate is ≳ 10 3 yr –1 Gpc –3 . Such a possibility will be unambiguously tested in the era of gravitational wave astronomy.

  20. Search for very-high-energy emission from Gamma-ray Bursts using the first 18 months of data from the HAWC Gamma-ray Observatory

    OpenAIRE

    The HAWC collaboration; Alfaro, R.; Alvarez, C.; Álvarez, J. D.; Arceo, R.; Arteaga-Velázquez, J. C.; Rojas, D. Avila; Solares, H. A. Ayala; Barber, A. S.; Bautista-Elivar, N.; Becerril, A.; Belmont-Moreno, E.; BenZvi, S. Y.; Bernal, A.; Braun, J.

    2017-01-01

    The High Altitude Water Cherenkov (HAWC) Gamma-ray Observatory is an extensive air shower detector operating in central Mexico, which has recently completed its first two years of full operations. If for a burst like GRB 130427A at a redshift of 0.34 and a high-energy component following a power law with index -1.66, the high-energy component is extended to higher energies with no cut-off other than from extragalactic background light attenuation, HAWC would observe gamma rays with a peak ene...

  1. Burst of Energy. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1992-12-01

    The Discovery Center of Idaho (DCI) was the recipient of a grant from US DOE`s Museum Science Education Program to build six permanent energy related exhibits to provide the public with hands-on experience with energy issues. Because of its volunteer support system, DC was able to build eleven exhibits. These exhibits are described and photographs are included. The signs used for the exhibits are reproduced as well as the materials used to advertise them to the public. Examples of DCI`s newsletter are included that mention the new exhibits.

  2. Observations of the highest energy gamma-rays from gamma-ray bursts

    International Nuclear Information System (INIS)

    Dingus, Brenda L.

    2001-01-01

    EGRET has extended the highest energy observations of gamma-ray bursts to GeV gamma rays. Such high energies imply the fireball that is radiating the gamma-rays has a bulk Lorentz factor of several hundred. However, EGRET only detected a few gamma-ray bursts. GLAST will likely detect several hundred bursts and may extend the maximum energy to a few 100 GeV. Meanwhile new ground based detectors with sensitivity to gamma-ray bursts are beginning operation, and one recently reported evidence for TeV emission from a burst

  3. First limits on the very-high energy gamma-ray afterglow emission of a fast radio burst. H.E.S.S. observations of FRB 150418

    Science.gov (United States)

    H.E.S.S. Collaboration; Abdalla, H.; Abramowski, A.; Aharonian, F.; Ait Benkhali, F.; Akhperjanian, A. G.; Andersson, T.; Angüner, E. O.; Arakawa, M.; Arrieta, M.; Aubert, P.; Backes, M.; Balzer, A.; Barnard, M.; Becherini, Y.; Becker Tjus, J.; Berge, D.; Bernhard, S.; Bernlöhr, K.; Blackwell, R.; Böttcher, M.; Boisson, C.; Bolmont, J.; Bordas, P.; Bregeon, J.; Brun, F.; Brun, P.; Bryan, M.; Büchele, M.; Bulik, T.; Capasso, M.; Carr, J.; Casanova, S.; Cerruti, M.; Chakraborty, N.; Chalme-Calvet, R.; Chaves, R. C. G.; Chen, A.; Chevalier, J.; Chrétien, M.; Coffaro, M.; Colafrancesco, S.; Cologna, G.; Condon, B.; Conrad, J.; Cui, Y.; Davids, I. D.; Decock, J.; Degrange, B.; Deil, C.; Devin, J.; Dewilt, P.; Dirson, L.; Djannati-Ataï, A.; Domainko, W.; Donath, A.; Drury, L. O.'c.; Dutson, K.; Dyks, J.; Edwards, T.; Egberts, K.; Eger, P.; Ernenwein, J.-P.; Eschbach, S.; Farnier, C.; Fegan, S.; Fernandes, M. V.; Fiasson, A.; Fontaine, G.; Förster, A.; Funk, S.; Füßling, M.; Gabici, S.; Gajdus, M.; Gallant, Y. A.; Garrigoux, T.; Giavitto, G.; Giebels, B.; Glicenstein, J. F.; Gottschall, D.; Goyal, A.; Grondin, M.-H.; Hahn, J.; Haupt, M.; Hawkes, J.; Heinzelmann, G.; Henri, G.; Hermann, G.; Hervet, O.; Hinton, J. A.; Hofmann, W.; Hoischen, C.; Holler, M.; Horns, D.; Ivascenko, A.; Iwasaki, H.; Jacholkowska, A.; Jamrozy, M.; Janiak, M.; Jankowsky, D.; Jankowsky, F.; Jingo, M.; Jogler, T.; Jouvin, L.; Jung-Richardt, I.; Kastendieck, M. A.; Katarzyński, K.; Katsuragawa, M.; Katz, U.; Kerszberg, D.; Khangulyan, D.; Khélifi, B.; Kieffer, M.; King, J.; Klepser, S.; Klochkov, D.; Kluźniak, W.; Kolitzus, D.; Komin, Nu.; Kosack, K.; Krakau, S.; Kraus, M.; Krüger, P. P.; Laffon, H.; Lamanna, G.; Lau, J.; Lees, J.-P.; Lefaucheur, J.; Lefranc, V.; Lemière, A.; Lemoine-Goumard, M.; Lenain, J.-P.; Leser, E.; Lohse, T.; Lorentz, M.; Liu, R.; López-Coto, R.; Lypova, I.; Marandon, V.; Marcowith, A.; Mariaud, C.; Marx, R.; Maurin, G.; Maxted, N.; Mayer, M.; Meintjes, P. J.; Meyer, M.; Mitchell, A. M. W.; Moderski, R.; Mohamed, M.; Mohrmann, L.; Morå, K.; Moulin, E.; Murach, T.; Nakashima, S.; de Naurois, M.; Niederwanger, F.; Niemiec, J.; Oakes, L.; O'Brien, P.; Odaka, H.; Öttl, S.; Ohm, S.; Ostrowski, M.; Oya, I.; Padovani, M.; Panter, M.; Parsons, R. D.; Pekeur, N. W.; Pelletier, G.; Perennes, C.; Petrucci, P.-O.; Peyaud, B.; Piel, Q.; Pita, S.; Poon, H.; Prokhorov, D.; Prokoph, H.; Pühlhofer, G.; Punch, M.; Quirrenbach, A.; Raab, S.; Reimer, A.; Reimer, O.; Renaud, M.; de Los Reyes, R.; Richter, S.; Rieger, F.; Romoli, C.; Rowell, G.; Rudak, B.; Rulten, C. B.; Sahakian, V.; Saito, S.; Salek, D.; Sanchez, D. A.; Santangelo, A.; Sasaki, M.; Schlickeiser, R.; Schüssler, F.; Schulz, A.; Schwanke, U.; Schwemmer, S.; Seglar-Arroyo, M.; Settimo, M.; Seyffert, A. S.; Shafi, N.; Shilon, I.; Simoni, R.; Sol, H.; Spanier, F.; Spengler, G.; Spies, F.; Stawarz, Ł.; Steenkamp, R.; Stegmann, C.; Stycz, K.; Sushch, I.; Takahashi, T.; Tavernet, J.-P.; Tavernier, T.; Taylor, A. M.; Terrier, R.; Tibaldo, L.; Tiziani, D.; Tluczykont, M.; Trichard, C.; Tsuji, N.; Tuffs, R.; Uchiyama, Y.; van der Walt, D. J.; van Eldik, C.; van Rensburg, C.; van Soelen, B.; Vasileiadis, G.; Veh, J.; Venter, C.; Viana, A.; Vincent, P.; Vink, J.; Voisin, F.; Völk, H. J.; Vuillaume, T.; Wadiasingh, Z.; Wagner, S. J.; Wagner, P.; Wagner, R. M.; White, R.; Wierzcholska, A.; Willmann, P.; Wörnlein, A.; Wouters, D.; Yang, R.; Zabalza, V.; Zaborov, D.; Zacharias, M.; Zanin, R.; Zdziarski, A. A.; Zech, A.; Zefi, F.; Ziegler, A.; Żywucka, N.; Superb Collaboration; Jankowski, F.; Keane, E. F.; Petroff, E.

    2017-01-01

    Aims: Following the detection of the fast radio burst FRB150418 by the SUPERB project at the Parkes radio telescope, we aim to search for very-high energy gamma-ray afterglow emission. Methods: Follow-up observations in the very-high energy gamma-ray domain were obtained with the H.E.S.S. imaging atmospheric Cherenkov telescope system within 14.5 h of the radio burst. Results: The obtained 1.4 h of gamma-ray observations are presented and discussed. At the 99% C.L. we obtained an integral upper limit on the gamma-ray flux of Φγ(E > 350 GeV) FRB 150418. Conclusions: No hints for high-energy afterglow emission of FRB 150418 were found. Taking absorption on the extragalactic background light into account and assuming a distance of z = 0.492 based on radio and optical counterpart studies and consistent with the FRB dispersion, we constrain the gamma-ray luminosity at 1 TeV to L < 5.1 × 1047 erg/s at 99% C.L.

  4. Gamma-ray bursts at high redshift

    NARCIS (Netherlands)

    Wijers, R.A.M.J.

    1999-01-01

    Gamma-ray bursts are much brighter than supernovae, and could therefore possibly probe the Universe to high redshift. The presently established GRB redshifts range from 0.83 to 5, and quite possibly even beyond that. Since most proposed mechanisms for GRB link them closely to deaths of massive

  5. Pair creation by very high-energy photons in gamma-ray bursts a unified picture for the energetics of GRBs

    CERN Document Server

    Totani, T

    1999-01-01

    The extreme energetics of the gamma-ray burst (GRB) 990123 have revealed that some GRBs emit quite a large amount of energy, and the total energy release from GRBs seems to change from burst to burst by a factor of 10/sup 2/-10/sup $9 3/ as E/sub gamma , iso/~10/sup 52-55/ erg, where E/sub gamma , iso/ is the observed GRB energy when the radiation is isotropic. If all GRBs are triggered by similar events, such a wide dispersion in energy release seems odd. The $9 author proposes a unified picture for the energetics of GRBs, in which all GRB events release roughly the same amount of energy E/sub iso/~10 /sup 55-56/ erg relativistic motion, with the baryon load problem almost resolved. A mild $9 dispersion in the initial Lorentz factor ( Gamma ) results in a difference of E/sub gamma , iso/ by up to a factor of m/sub p//m/sub e/~10/sup 3/. Protons work as `a hidden energy reservoir' of the total GRB energy, and E/sub gamma , $9 iso/ depends on the energy transfer efficiency from protons into electrons (or posit...

  6. iPTF14yb: The First Discovery of a Gamma-Ray Burst Afterglow Independent of a High-Energy Trigger

    Science.gov (United States)

    Cenko, S. Bradley; Urban, Alex L.; Perley, Daniel A.; Horesh, Assaf; Corsi, Alessandra; Fox, Derek B.; Cao, Yi; Kasliwal, Mansi M.; Lien, Amy; Arcavi, Iair; hide

    2015-01-01

    We report here the discovery by the Intermediate Palomar Transient Factory (iPTF) of iPTF14yb, a luminous (Mr >> -27.8 mag), cosmological (redshift 1.9733), rapidly fading optical transient. We demonstrate, based on probabilistic arguments and a comparison with the broader population, that iPTF14yb is the optical afterglow of the long-duration gamma-ray burst GRB 140226A. This marks the first unambiguous discovery of a GRB afterglow prior to (and thus entirely independent of) an associated high-energy trigger. We estimate the rate of iPTF14yb-like sources (i.e., cosmologically distant relativistic explosions) based on iPTF observations, inferring an all-sky value of Rrel = 610/yr (68% confidence interval of 110-2000/yr). Our derived rate is consistent (within the large uncertainty) with the all-sky rate of on-axis GRBs derived by the Swift satellite. Finally, we briefly discuss the implications of the nondetection to date of bona fide "orphan" afterglows (i.e., those lacking detectable high-energy emission) on GRB beaming and the degree of baryon loading in these relativistic jets.

  7. On the possibility of highest energy cosmic rays bursts and their correlation with gamma rays bursts e.g. March 5th, 1979 event

    International Nuclear Information System (INIS)

    Drukier, K.

    1982-01-01

    The avalanche production of magnetic monopoles is possible in neutron stars. Big part of the magnetic field energy can be used to accelerate a pulse of 10 30 monopoles to the energy E > approximately 10 17 eV. Thus the neutron stars may be ''point'' sources of bursts of highest energy Cosmic Rays. The emission of brehmsstrahlung photons by these highly relativistic monopoles would be seen as X and gamma bursts. This ''exotic'' model for March 5th, 1979 event, predicts that it has been followed by burst of highest energy Cosmic Rays coming from the direction of LMC supernovae remanent N49

  8. High energy astrophysics

    International Nuclear Information System (INIS)

    Engel, A.R.

    1979-01-01

    High energy astrophysical research carried out at the Blackett Laboratory, Imperial College, London is reviewed. Work considered includes cosmic ray particle detection, x-ray astronomy, gamma-ray astronomy, gamma and x-ray bursts. (U.K.)

  9. BurstMem: A High-Performance Burst Buffer System for Scientific Applications

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Teng [Auburn University, Auburn, Alabama; Oral, H Sarp [ORNL; Wang, Yandong [Auburn University, Auburn, Alabama; Settlemyer, Bradley W [ORNL; Atchley, Scott [ORNL; Yu, Weikuan [Auburn University, Auburn, Alabama

    2014-01-01

    The growth of computing power on large-scale sys- tems requires commensurate high-bandwidth I/O system. Many parallel file systems are designed to provide fast sustainable I/O in response to applications soaring requirements. To meet this need, a novel system is imperative to temporarily buffer the bursty I/O and gradually flush datasets to long-term parallel file systems. In this paper, we introduce the design of BurstMem, a high- performance burst buffer system. BurstMem provides a storage framework with efficient storage and communication manage- ment strategies. Our experiments demonstrate that BurstMem is able to speed up the I/O performance of scientific applications by up to 8.5 on leadership computer systems.

  10. Z-burst scenario for the highest energy cosmic rays

    International Nuclear Information System (INIS)

    Fodor, Z.

    2002-10-01

    The origin of highest energy cosmic rays is yet unknown. An appealing possibility is the so-called Z-burst scenario, in which a large fraction of these cosmic rays are decay products of Z bosons produced in the scattering of ultrahigh energy neutrinos on cosmological relic neutrinos. The comparison between the observed and predicted spectra constrains the mass of the heaviest neutrino. The required neutrino mass is fairly robust against variations of the presently unknown quantities, such as the amount of relic neutrino clustering, the universal photon radio background and the extragalactic magnetic field. Considering different possibilities for the ordinary cosmic rays the required neutrino masses are determined. In the most plausible case that the ordinary cosmic rays are of extragalactic origin and the universal radio background is strong enough to suppress high energy photons, the required neutrino mass is 0.08 eV ≤ m ν ≤ 0.40 eV. The required ultrahigh energy neutrino flux should be detected in the near future by experiments such as AMANDA, RICE or the Pierre Auger Observatory. (orig.)

  11. High sensitivity neutron bursts detecting system

    International Nuclear Information System (INIS)

    Shyam, A.; Kaushik, T.C.; Srinivasan, M.; Kulkarni, L.V.

    1993-01-01

    Technique and instrumentation to detect multiplicity of fast neutrons, emitted in sharp bursts, has been developed. A bank of 16 BF 3 detectors, in an appropriate thermalising assembly, efficiency ∼ 16%, is used to detect neutron bursts. The output from this setup, through appropriate electronics, is divided into two paths. The first is directly connected to a computer controlled scalar. The second is connected to another similar scalar through a delay time unit (DTU). The DTU design is such that once it is triggered by a count pulse than it does not allow any counts to be recorded for a fixed dead time set at ∼ 100 μs. The difference in counts recorded directly and through DTU gives the total number of neutrons produced in bursts. This setup is being used to study lattice cracking, anomalous effects in solid deuterium systems and various reactor physics experiments. (author). 3 refs., 1 fig

  12. High repetition rate burst-mode spark gap

    International Nuclear Information System (INIS)

    Faltens, A.; Reginato, L.; Hester, R.; Chesterman, A.; Cook, E.; Yokota, T.; Dexter, W.

    1978-01-01

    Results are presented on the design and testing of a pressurized gas blown spark gap switch capable of high repetition rates in a burst mode of operation. The switch parameters which have been achieved are as follows: 220-kV, 42-kA, a five pulse burst at 1-kHz, 12-ns risetime, 2-ns jitter at a pulse width of 50-ns

  13. Direct observations of low-energy solar electrons associated with a type 3 solar radio burst

    Science.gov (United States)

    Frank, L. A.; Gurnett, D. A.

    1972-01-01

    On 6 April 1971 a solar X-ray flare and a type 3 solar radio noise burst were observed with instrumentation on the eccentric-orbiting satellite IMP 6. The type 3 solar radio noise burst was detected down to a frequency of 31 kHz. A highly anisotropic packet of low-energy solar electron intensities arrived at the satellite approximately 6000 seconds after the onset of the solar flare. This packet of solar electron intensities was observed for 4200 seconds. Maximum differential intensities of the solar electrons were in the energy range of one to several keV. The frequency drift rate of the type 3 radio noise at frequencies below 178 kHz also indicated an average particle speed corresponding to that of a 3-keV electron. The simultaneous observations of these solar electron intensities and of the type 3 solar radio burst are presented, and their interrelationships are explored.

  14. Energy budget in collimated gamma-ray bursts

    International Nuclear Information System (INIS)

    Tudose, Valeriu; Biermann, Peter

    2003-01-01

    There is increasing evidence for the existence of collimation in some, if not most, of the gamma-ray bursts. This would have direct implications, for instance, on the energy budget, the rate of events, but also indirect consequences for the theoretical models because it provides a tool to differentiate between their predictions. We consider the case of a structured jet, i.e. we assume the energy within the jet varies as a power-law, being a function of the angle between the jet axis and an arbitrary direction. We analyze first the situation in which the jet axis and the line of sight have a particular orientation, then we relax this assumption by allowing for an arbitrary viewing angle with respect to the symmetry axis of the jet. A qualitative study of the total energy content of the jet is performed. It turns out that the 'real' energy could be higher than what is inferred from observations. (authors)

  15. Identifying high-redshift gamma-ray bursts with RATIR

    Energy Technology Data Exchange (ETDEWEB)

    Littlejohns, O. M.; Butler, N. R. [School of Earth and Space Exploration, Arizona State University, AZ 85287 (United States); Cucchiara, A. [Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Watson, A. M.; Lee, W. H.; Richer, M. G.; De Diego, J. A.; Georgiev, L.; González, J.; Román-Zúñiga, C. G. [Instituto de Astronomía, Universidad Nacional Autónoma de México, Apartado Postal 70-264, 04510 México, D. F. (Mexico); Kutyrev, A. S.; Troja, E.; Gehrels, N.; Moseley, H. [NASA, Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Klein, C. R.; Fox, O. D.; Bloom, J. S. [Astronomy Department, University of California, Berkeley, CA 94720-7450 (United States); Prochaska, J. X.; Ramirez-Ruiz, E. [Department of Astronomy and Astrophysics, UCO/Lick Observatory, University of California, 1156 High Street, Santa Cruz, CA 95064 (United States)

    2014-07-01

    We present a template-fitting algorithm for determining photometric redshifts, z {sub phot}, of candidate high-redshift gamma-ray bursts (GRBs). Using afterglow photometry, obtained by the Reionization and Transients InfraRed (RATIR) camera, this algorithm accounts for the intrinsic GRB afterglow spectral energy distribution, host dust extinction, and the effect of neutral hydrogen (local and cosmological) along the line of sight. We present the results obtained by this algorithm and the RATIR photometry of GRB 130606A, finding a range of best-fit solutions, 5.6 < z {sub phot} < 6.0, for models of several host dust extinction laws (none, the Milky Way, Large Magellanic Clouds, and Small Magellanic Clouds), consistent with spectroscopic measurements of the redshift of this GRB. Using simulated RATIR photometry, we find that our algorithm provides precise measures of z {sub phot} in the ranges of 4 < z {sub phot} ≲ 8 and 9 < z {sub phot} < 10 and can robustly determine when z {sub phot} > 4. Further testing highlights the required caution in cases of highly dust-extincted host galaxies. These tests also show that our algorithm does not erroneously find z {sub phot} < 4 when z {sub sim} > 4, thereby minimizing false negatives and allowing us to rapidly identify all potential high-redshift events.

  16. Identifying high-redshift gamma-ray bursts with RATIR

    International Nuclear Information System (INIS)

    Littlejohns, O. M.; Butler, N. R.; Cucchiara, A.; Watson, A. M.; Lee, W. H.; Richer, M. G.; De Diego, J. A.; Georgiev, L.; González, J.; Román-Zúñiga, C. G.; Kutyrev, A. S.; Troja, E.; Gehrels, N.; Moseley, H.; Klein, C. R.; Fox, O. D.; Bloom, J. S.; Prochaska, J. X.; Ramirez-Ruiz, E.

    2014-01-01

    We present a template-fitting algorithm for determining photometric redshifts, z phot , of candidate high-redshift gamma-ray bursts (GRBs). Using afterglow photometry, obtained by the Reionization and Transients InfraRed (RATIR) camera, this algorithm accounts for the intrinsic GRB afterglow spectral energy distribution, host dust extinction, and the effect of neutral hydrogen (local and cosmological) along the line of sight. We present the results obtained by this algorithm and the RATIR photometry of GRB 130606A, finding a range of best-fit solutions, 5.6 < z phot < 6.0, for models of several host dust extinction laws (none, the Milky Way, Large Magellanic Clouds, and Small Magellanic Clouds), consistent with spectroscopic measurements of the redshift of this GRB. Using simulated RATIR photometry, we find that our algorithm provides precise measures of z phot in the ranges of 4 < z phot ≲ 8 and 9 < z phot < 10 and can robustly determine when z phot > 4. Further testing highlights the required caution in cases of highly dust-extincted host galaxies. These tests also show that our algorithm does not erroneously find z phot < 4 when z sim > 4, thereby minimizing false negatives and allowing us to rapidly identify all potential high-redshift events.

  17. Transverse mode instabilities in burst operation of high-power fiber laser systems

    Science.gov (United States)

    Jauregui, Cesar; Stihler, Christoph; Tünnermann, Andreas; Limpert, Jens

    2018-02-01

    We propose, to the best of our knowledge, the first mitigation strategy for TMI based on controlling the phase shift between the thermally-induced index grating and the modal intensity pattern. In particular, in this work we present a study of transverse mode instabilities in burst operation in a high-power fiber laser system. It is shown that, with a careful choice of the parameters, this operation regime can potentially lead to the mitigation of TMI by forcing an energy transfer from the higher-order-modes into the fundamental mode during the burst.

  18. Possibility of observing high energy neutrinos from gamma bursts, with the Antanares telescope, feasibility study; Possibilite d'observation, par le telescope antares, de neutrinos de haute energie associes aux sursauts gamma et validation des techniques de detection a l'aide d'un prototype

    Energy Technology Data Exchange (ETDEWEB)

    Kouchner, A

    2001-04-01

    The European Antares collaboration intends to build a deep-sea neutrino telescope with a detection surface of about 1/10 km{sup 2} in the Mediterranean sea. The universe is transparent to neutrinos, so their study provides a unique means of improving our knowledge of the nature and origin of cosmic rays and their emission from the most powerful astrophysical sources in the cosmos. Neutrinos also offer the possibility of opening a new energy window (E>TeV) for observation of the universe. The first part of the thesis is dedicated to a study of the possibility of using the future telescope to look for correlations between gamma-ray bursts and high-energy neutrinos. It is based, on one hand, on the predictions of neutrino fluxes from gamma-ray bursts in the framework of the theoretical model of 'fireballs', and, on the other hand, on the temporal properties of the gamma-ray bursts in the 4. BATSE catalogue. The second part of the thesis presents the results obtained with a prototype detector line deployed, at the end of 1999, some forty km south-west off Marseilles. The objective was to operate a complete apparatus, similar to the future detector lines, from the shore, and under realistic conditions. Data from 7 photomultiplier tubes disposed along the detector line were transmitted through 37 km of optical fiber to the shore, where they were used to reconstruct tracks due to atmospheric muons, thus validating the detection principles and methods. (author)

  19. High-latitude Pc 1 bursts arising in the dayside boundary layer region

    International Nuclear Information System (INIS)

    Hansen, H.J.; Fraser, B.J.; Menk, F.W.; Hu, Y.D.; Newell, P.T.; Meng, C.I.; Morris, R.J.

    1992-01-01

    Dayside Pc 1 geomagnetic pulsation bursts have been studied using a three-station array of induction magnetometers located at high latitudes. Associated magnetic variations in the form of solitary pulses often lead the Pc 1 bursts by 1 to 2 min. These pulses are typically associated with riometer absorption events and consequently the precipitation of fluxes of keV electrons. The Pc 1 bursts are interpreted as resulting from ion cyclotron waves which have propagated to the ionosphere from the equatorial boundary layer region. The associated boundary layer ions, identified by the low-altitude DMSP F7 satellite, range between 1 and 5 keV in energy. These particles are considered to be the most likely free energy source for the ion cyclotron waves. It is considered that such resonant ions enter the magnetosphere via the cleft and cusp because this enables a prenoon time of occurrence of most of the observations to be explained. Measured time delays of 40 to 120 s between the associated riometer absorption and Pc 2 bursts are consistent with an ion cyclotron wave generations region located in the equatorial magnetosphere

  20. Pulse-burst PIV in a high-speed wind tunnel

    International Nuclear Information System (INIS)

    Beresh, Steven; Kearney, Sean; Wagner, Justin; Guildenbecher, Daniel; Henfling, John; Spillers, Russell; Pruett, Brian; Jiang, Naibo; Slipchenko, Mikhail; Mance, Jason; Roy, Sukesh

    2015-01-01

    Time-resolved particle image velocimetry (TR-PIV) has been achieved in a high-speed wind tunnel, providing velocity field movies of compressible turbulence events. The requirements of high-speed flows demand greater energy at faster pulse rates than possible with the TR-PIV systems developed for low-speed flows. This has been realized using a pulse-burst laser to obtain movies at up to 50 kHz, with higher speeds possible at the cost of spatial resolution. The constraints imposed by use of a pulse-burst laser are limited burst duration of 10.2 ms and a low duty cycle for data acquisition. Pulse-burst PIV has been demonstrated in a supersonic jet exhausting into a transonic crossflow and in transonic flow over a rectangular cavity. The velocity field sequences reveal the passage of turbulent structures and can be used to find velocity power spectra at every point in the field, providing spatial distributions of acoustic modes. The present work represents the first use of TR-PIV in a high-speed ground-test facility. (paper)

  1. Acoustic characteristics of bubble bursting at the surface of a high-viscosity liquid

    International Nuclear Information System (INIS)

    Liu Xiao-Bo; Zhang Jian-Run; Li Pu

    2012-01-01

    An acoustic pressure model of bubble bursting is proposed. An experiment studying the acoustic characteristics of the bursting bubble at the surface of a high-viscosity liquid is reported. It is found that the sudden bursting of a bubble at the high-viscosity liquid surface generates N-shape wave at first, then it transforms into a jet wave. The fundamental frequency of the acoustic signal caused by the bursting bubble decreases linearly as the bubble size increases. The results of the investigation can be used to understand the acoustic characteristics of bubble bursting. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  2. Gamma Ray Bursts - Observations

    Science.gov (United States)

    Gehrels, N.; Cannizzo, J. K.

    2010-01-01

    We are in an exciting period of discovery for gamma-ray bursts. The Swift observatory is detecting 100 bursts per year, providing arcsecond localizations and sensitive observations of the prompt and afterglow emission. The Fermi observatory is observing 250 bursts per year with its medium-energy GRB instrument and about 10 bursts per year with its high-energy LAT instrument. In addition, rapid-response telescopes on the ground are providing new capabilities to study optical emission during the prompt phase and spectral signatures of the host galaxies. The combined data set is enabling great advances in our understanding of GRBs including afterglow physics, short burst origin, and high energy emission.

  3. High-z Universe with Gamma Ray Bursts

    Science.gov (United States)

    Kouveliotou, C.

    2011-01-01

    Gamma-Ray Bursts (GRBs) are the most luminous explosions in space and trace the cosmic star formation history back to the first generations of stars. Their bright afterglows allow us to trace the abundances of heavy elements to large distances, thereby measuring cosmic chemical evolution. To date GRBs have been detected up to distances of z=8.23 and possibly even beyond z9. This makes GRBs a unique and powerful tool to probe the high-z Universe up to the re-ionization era. We discuss the current status of the field, place it in context with other probes, and also discuss new mission concepts that have been planned to utilize GRBs as probes.

  4. Possibility of observing high energy neutrinos from gamma bursts, with the Antanares telescope, feasibility study; Possibilite d'observation, par le telescope antares, de neutrinos de haute energie associes aux sursauts gamma et validation des techniques de detection a l'aide d'un prototype

    Energy Technology Data Exchange (ETDEWEB)

    Kouchner, A

    2001-04-01

    The European Antares collaboration intends to build a deep-sea neutrino telescope with a detection surface of about 1/10 km{sup 2} in the Mediterranean sea. The universe is transparent to neutrinos, so their study provides a unique means of improving our knowledge of the nature and origin of cosmic rays and their emission from the most powerful astrophysical sources in the cosmos. Neutrinos also offer the possibility of opening a new energy window (E>TeV) for observation of the universe. The first part of the thesis is dedicated to a study of the possibility of using the future telescope to look for correlations between gamma-ray bursts and high-energy neutrinos. It is based, on one hand, on the predictions of neutrino fluxes from gamma-ray bursts in the framework of the theoretical model of 'fireballs', and, on the other hand, on the temporal properties of the gamma-ray bursts in the 4. BATSE catalogue. The second part of the thesis presents the results obtained with a prototype detector line deployed, at the end of 1999, some forty km south-west off Marseilles. The objective was to operate a complete apparatus, similar to the future detector lines, from the shore, and under realistic conditions. Data from 7 photomultiplier tubes disposed along the detector line were transmitted through 37 km of optical fiber to the shore, where they were used to reconstruct tracks due to atmospheric muons, thus validating the detection principles and methods. (author)

  5. External Shock in a Multi-bursting Gamma-Ray Burst: Energy Injection Phase Induced by the Later Launched Ejecta

    Science.gov (United States)

    Lin, Da-Bin; Huang, Bao-Quan; Liu, Tong; Gu, Wei-Min; Mu, Hui-Jun; Liang, En-Wei

    2018-01-01

    Central engines of gamma-ray bursts (GRBs) may be intermittent and launch several episodes of ejecta separated by a long quiescent interval. In this scenario, an external shock is formed due to the propagation of the first launched ejecta into the circum-burst medium and the later launched ejecta may interact with the external shock at a later period. Owing to the internal dissipation, the later launched ejecta may be observed at a later time (t jet). In this paper, we study the relation of t b and t jet, where t b is the collision time of the later launched ejecta with the formed external shock. It is found that the relation of t b and t jet depends on the bulk Lorentz factor (Γjet) of the later launched ejecta and the density (ρ) of the circum-burst medium. If the value of Γjet or ρ is low, the t b would be significantly larger than t jet. However, the t b ∼ t jet can be found if the value of Γjet or ρ is significantly large. Our results can explain the large lag of the optical emission relative to the γ-ray/X-ray emission in GRBs, e.g., GRB 111209A. For GRBs with a precursor, our results suggest that the energy injection into the external shock and thus more than one external-reverse shock may appear in the main prompt emission phase. According to our model, we estimate the Lorentz factor of the second launched ejecta in GRB 160625B.

  6. Prediction of failure strain and burst pressure in high yield-to-tensile strength ratio linepipe

    International Nuclear Information System (INIS)

    Law, M.; Bowie, G.

    2007-01-01

    Failure pressures and strains were predicted for a number of burst tests as part of a project to explore failure strain in high yield-to-tensile strength ratio linepipe. Twenty-three methods for predicting the burst pressure and six methods of predicting the failure strain are compared with test results. Several methods were identified which gave accurate and reliable estimates of burst pressure. No method of accurately predicting the failure strain was found, though the best was noted

  7. Prediction of failure strain and burst pressure in high yield-to-tensile strength ratio linepipe

    Energy Technology Data Exchange (ETDEWEB)

    Law, M. [Institute of Materials and Engineering Science, Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, NSW (Australia)]. E-mail: mlx@ansto.gov.au; Bowie, G. [BlueScope Steel Ltd., Level 11, 120 Collins St, Melbourne, Victoria 3000 (Australia)

    2007-08-15

    Failure pressures and strains were predicted for a number of burst tests as part of a project to explore failure strain in high yield-to-tensile strength ratio linepipe. Twenty-three methods for predicting the burst pressure and six methods of predicting the failure strain are compared with test results. Several methods were identified which gave accurate and reliable estimates of burst pressure. No method of accurately predicting the failure strain was found, though the best was noted.

  8. REPEATING FAST RADIO BURSTS FROM HIGHLY MAGNETIZED PULSARS TRAVELING THROUGH ASTEROID BELTS

    International Nuclear Information System (INIS)

    Dai, Z. G.; Wang, J. S.; Huang, Y. F.; Wu, X. F.

    2016-01-01

    Very recently, Spitler et al. and Scholz et al. reported their detections of 16 additional bright bursts in the direction of the fast radio burst (FRB) 121102. This repeating FRB is inconsistent with all of the catastrophic event models put forward previously for hypothetically non-repeating FRBs. Here, we propose a different model, in which highly magnetized pulsars travel through the asteroid belts of other stars. We show that a repeating FRB could originate from such a pulsar encountering a large number of asteroids in the belt. During each pulsar-asteroid impact, an electric field induced outside of the asteroid has such a large component parallel to the stellar magnetic field that electrons are torn off the asteroidal surface and accelerated to ultra-relativistic energies instantaneously. The subsequent movement of these electrons along magnetic field lines will cause coherent curvature radiation, which can account for all of the properties of an FRB. In addition, this model can self-consistently explain the typical duration, luminosity, and repetitive rate of the 17 bursts of FRB 121102. The predicted occurrence rate of repeating FRB sources may imply that our model would be testable in the next few years.

  9. REPEATING FAST RADIO BURSTS FROM HIGHLY MAGNETIZED PULSARS TRAVELING THROUGH ASTEROID BELTS

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Z. G.; Wang, J. S.; Huang, Y. F. [School of Astronomy and Space Science, Nanjing University, Nanjing 210093 (China); Wu, X. F., E-mail: dzg@nju.edu.cn [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China)

    2016-09-20

    Very recently, Spitler et al. and Scholz et al. reported their detections of 16 additional bright bursts in the direction of the fast radio burst (FRB) 121102. This repeating FRB is inconsistent with all of the catastrophic event models put forward previously for hypothetically non-repeating FRBs. Here, we propose a different model, in which highly magnetized pulsars travel through the asteroid belts of other stars. We show that a repeating FRB could originate from such a pulsar encountering a large number of asteroids in the belt. During each pulsar-asteroid impact, an electric field induced outside of the asteroid has such a large component parallel to the stellar magnetic field that electrons are torn off the asteroidal surface and accelerated to ultra-relativistic energies instantaneously. The subsequent movement of these electrons along magnetic field lines will cause coherent curvature radiation, which can account for all of the properties of an FRB. In addition, this model can self-consistently explain the typical duration, luminosity, and repetitive rate of the 17 bursts of FRB 121102. The predicted occurrence rate of repeating FRB sources may imply that our model would be testable in the next few years.

  10. Radio and X-ray observations of a multiple impulsive solar burst with high time resolution

    International Nuclear Information System (INIS)

    Kosugi, T.

    1981-01-01

    A well-developed multiple impulsive microwave burst occurred on February 17, 1979 simultaneously with a hard X-ray burst and a large group of type III bursts at metric wavelengths. The whole event is composed of serveral subgroups of elementary spike bursts. Detailed comparisons between these three classes of emissions with high time resolution of approx. equal to0.5 s reveal that individual type III bursts coincide in time with corresponding elementary X-ray and microwave spike bursts. It suggests that a non-thermal electron pulse generating a type III spike burst is produced simultaneously with those responsible for the corresponding hard X-ray and microwave spike bursts. The rise and decay characteristic time scales of the elementary spike burst are << 1 s, and approx. equal to1 s and approx. equal to3 s for type III, hard X-ray and microwave emissions respectively. Radio interferometric observations made at 17 GHz reveal that the spatial structure varies from one subgroup to others while it remains unchanged in a subgroup. Spectral evolution of the microwave burst seems to be closely related to the spatial evolution. The spatial evolution together with the spectral evolution suggests that the electron-accelerating region shifts to a different location after it stays at one location for several tens of seconds, duration of a subgroup of elementary spike bursts. We discuss several requirements for a model of the impulsive burst which come out from these observational results, and propose a migrating double-source model. (orig.)

  11. Weak-scale hidden sector and energy transport in fireball models of gamma-ray bursts

    International Nuclear Information System (INIS)

    Demir, Durmus A.; Mosquera Cuesta, Herman J.

    2000-12-01

    The annihilation of pairs of very weakly interacting particles in the neighborhood of gamma-ray sources is introduced here as a plausible mechanism to overcome the baryon load problem. This way we can explain how these very high energy gamma-ray bursts can be powered at the onset of very energetic events like supernovae (collapsars) explosions or coalescences of binary neutron stars. Our approach uses the weak-scale hidden sector models in which the Higgs sector of the standard model is extended to include a gauge singlet that only interacts with the Higgs particle. These particles would be produced either during the implosion of the red supergiant star core or at the aftermath of a neutron star binary merger. The whole energetics and timescales of the relativistic blast wave, the fireball, are reproduced. (author)

  12. Burst analysis tool for developing neuronal networks exhibiting highly varying action potential dynamics

    Directory of Open Access Journals (Sweden)

    Fikret Emre eKapucu

    2012-06-01

    Full Text Available In this paper we propose a firing statistics based neuronal network burst detection algorithm for neuronal networks exhibiting highly variable action potential dynamics. Electrical activity of neuronal networks is generally analyzed by the occurrences of spikes and bursts both in time and space. Commonly accepted analysis tools employ burst detection algorithms based on predefined criteria. However, maturing neuronal networks, such as those originating from human embryonic stem cells (hESC, exhibit highly variable network structure and time-varying dynamics. To explore the developing burst/spike activities of such networks, we propose a burst detection algorithm which utilizes the firing statistics based on interspike interval (ISI histograms. Moreover, the algorithm calculates interspike interval thresholds for burst spikes as well as for pre-burst spikes and burst tails by evaluating the cumulative moving average and skewness of the ISI histogram. Because of the adaptive nature of the proposed algorithm, its analysis power is not limited by the type of neuronal cell network at hand. We demonstrate the functionality of our algorithm with two different types of microelectrode array (MEA data recorded from spontaneously active hESC-derived neuronal cell networks. The same data was also analyzed by two commonly employed burst detection algorithms and the differences in burst detection results are illustrated. The results demonstrate that our method is both adaptive to the firing statistics of the network and yields successful burst detection from the data. In conclusion, the proposed method is a potential tool for analyzing of hESC-derived neuronal cell networks and thus can be utilized in studies aiming to understand the development and functioning of human neuronal networks and as an analysis tool for in vitro drug screening and neurotoxicity assays.

  13. Intermittent energy bursts and recurrent topological change of a twisting magnetic flux tube

    International Nuclear Information System (INIS)

    Amo, Hiroyoshi; Sato, Tetsuya; Kageyama, Akira.

    1994-09-01

    When continuously twisted, a magnetic flux tube suffers a large kink distortion in the middle part of the tube, like a knot-of-tension instability of a bundle of twisted rubber strings, and reconnection is triggered starting with the twisted field lines and quickly proceeding to the untwisted field lines at the twist-untwist boundary, whereby a giant burst-like energy release takes place. Subsequently, bursts occur intermittently and reconnection advances deeper into the untwisted region. Then, a companion pair of the linked twist-untwist flux tubes reconnect with each other to return to the original axisymmetric tube. The process is thus repeatable. (author)

  14. Study on spontaneous bursts of high voltage slow wave activities in electroencephalograms of the aged

    International Nuclear Information System (INIS)

    Yoshida, Ryoichi; Otomo, Eiichi

    1985-01-01

    100 EEGs with bursts of high voltage slow wave activities (bursts) were found in 1150 of aged subjects sixty years and over. In these cases computerized cranial tomography (CT) examinations were carried out within 60 days of EEG recordings and CT findings (bursts CTs) were compared with those of 100 cases without bursts (control CTs). Another 100 consecutive CTs of cases with matched the age and the disease were used as the control. The results were as follows: 1) In bursts CTs, the incidence of normal findings was only 7%, while it was 18% in control CTs. The difference was statistically significant (p<0.001). 2) Brain atrophy was remarkable in bursts CTs. In bursts CT, the incidence of brain atrophy showed more than minor degree was 89%, while it was 64% in control CTs. The difference was statistically significant (p<0.001). 3) The incidences of periventricular lucency (PVL), enlargement of the inferior and posterior horn of the lateral ventricle, basal ganglia calcification observed on CT were significantly higher (55%, 39%, 12%) in bursts CTs than in control CTs (p<0.01, p<0.01, p<0.05). 4) The incidence of focal lesions was lower in bursts CTs than in control CTs. In paticular, large lesions were recognized in only 3% of bursts CTs, whereas those were noted in 15% of control CTs. The difference was statistically significant (p<0.01). 5) Small lesions were recognized in 21% of neurological normal patients with bursts, while they were found in 5% of these of control CTs. 6) Frontal and thalamic lesions were found more frequently in bursts CTs (26%, 13%) than in control CTs (21%, 8%), but the difference was not statistically significant. 7) The correlation between the side showing high voltage of bursts and the side with lesions observed on CT was good. In this way, it may be conceivable that appearance of bursts is not due to only focal lesions but results from generalized brain disfunction, such as aging and others. (author)

  15. Model error assessment of burst capacity models for energy pipelines containing surface cracks

    International Nuclear Information System (INIS)

    Yan, Zijian; Zhang, Shenwei; Zhou, Wenxing

    2014-01-01

    This paper develops the probabilistic characteristics of the model errors associated with five well-known burst capacity models/methodologies for pipelines containing longitudinally-oriented external surface cracks, namely the Battelle and CorLAS™ models as well as the failure assessment diagram (FAD) methodologies recommended in the BS 7910 (2005), API RP579 (2007) and R6 (Rev 4, Amendment 10). A total of 112 full-scale burst test data for cracked pipes subjected internal pressure only were collected from the literature. The model error for a given burst capacity model is evaluated based on the ratios of the test to predicted burst pressures for the collected data. Analysis results suggest that the CorLAS™ model is the most accurate model among the five models considered and the Battelle, BS 7910, API RP579 and R6 models are in general conservative; furthermore, the API RP579 and R6 models are markedly more accurate than the Battelle and BS 7910 models. The results will facilitate the development of reliability-based structural integrity management of pipelines. - Highlights: • Model errors for five burst capacity models for pipelines containing surface cracks are characterized. • Basic statistics of the model errors are obtained based on test-to-predicted ratios. • Results will facilitate reliability-based design and assessment of energy pipelines

  16. Revisiting the Correlations of Peak Luminosity with Spectral Lag and Peak Energy of the Observed Gamma-ray Bursts

    Directory of Open Access Journals (Sweden)

    Yun-A Jo

    2016-12-01

    Full Text Available An analysis of light curves and spectra of observed gamma-ray bursts in gamma-ray ranges is frequently demanded because the prompt emission contains immediate details regarding the central engine of gamma-ray bursts (GRBs. We have revisited the relationship between the collimation-corrected peak luminosity and the spectral lag, investigating the lag-luminosity relationships in great detail by focusing on spectral lags resulting from all possible combinations of channels. Firstly, we compiled the opening angle data and demonstrated that the distribution of opening angles of 205 long GRBs is represented by a double Gaussian function having maxima at ~ 0.1 and ~ 0.3 radians. We confirmed that the peak luminosity and the spectral lag are anti-correlated, both in the observer frame and in the source frame. We found that, in agreement with our previous conclusion, the correlation coefficient improves significantly in the source frame. It should be noted that spectral lags involving channel 2 (25-50 keV yield high correlation coefficients, where Swift/Burst Alert Telescope (BAT has four energy channels (channel 1: 15-25 keV, channel 2: 25-50 keV, channel 3: 50-100 keV, channel 4: 100-200 keV. We also found that peak luminosity is positively correlated with peak energy.

  17. Evaluation of effective energy deposition in test fuel during power burst experiment in NSRR

    International Nuclear Information System (INIS)

    Ohnishi, Nobuaki; Inabe, Teruo

    1982-01-01

    In an inpile experiment to study the fuel behavior under reactivity-initiated accident conditions, it is of great importance to understand the time-dependent characteristics of the energy deposited in the test fuel by burst power. The evaluation of the time-dependent energy deposition requires the knowledge of the fission rates and energy deposition per fission in the test fuel, both as a function of time. In the present work, the authors attempted to evaluate the relative fission rate change in the test fuel subjected to the power burst testing in the NSRR through the measurements and analyses of the fission power changes in the NSRR. Utilizing a micro fission chamber and a conventional larger fission chamber, they successfully measured the reactor fission power change ranging over a dozen of decades in magnitude and a thousand seconds in time. The measured power transient agreed quite well with calculated results. In addition, the time-dependent energy deposition per fission in the test fuel including the energy contribution from the driver core was analytically evaluated. The analyses indicate that the energy of about 175 MeV/fission is promptly deposited in the test fuel and that the additional energy of about 11 MeV is deposited afterwards. Finally the fractions of energy deposited in the test fuel until various times after power burst were determined by coupling the time-dependent relative fissions and energy deposition per fission in the test fuel. The prompt energy deposition ranges from about 50 to 80% of the total energy deposition for the reactivity insertion between 1.5 and 4.7 $, and the remaining is the delayed energy deposition. (author)

  18. GRB 120521C at z ∼ 6 and the properties of high-redshift γ-ray bursts

    Energy Technology Data Exchange (ETDEWEB)

    Laskar, Tanmoy; Berger, Edo; Zauderer, B. Ashley; Margutti, Raffaella; Fong, Wen-fai [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Tanvir, Nial; Wiersema, Klaas [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Levan, Andrew [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Perley, Daniel [Department of Astronomy, California Institute of Technology, MC 249-17, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Menten, Karl [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Hrudkova, Marie [Isaac Newton Group of Telescopes, Apartado de Correos 321, E-387 00 Santa Cruz de la Palma, Canary Islands (Spain)

    2014-01-20

    We present optical, near-infrared, and radio observations of the afterglow of GRB 120521C. By modeling the multi-wavelength data set, we derive a photometric redshift of z ≈ 6.0, which we confirm with a low signal-to-noise ratio spectrum of the afterglow. We find that a model with a constant-density environment provides a good fit to the afterglow data, with an inferred density of n ≲ 0.05 cm{sup –3}. The radio observations reveal the presence of a jet break at t {sub jet} ≈ 7 d, corresponding to a jet opening angle of θ{sub jet} ≈ 3°. The beaming-corrected γ-ray and kinetic energies are E {sub γ} ≈ E{sub K} ≈ 3 × 10{sup 50} erg. We quantify the uncertainties in our results using a detailed Markov Chain Monte Carlo analysis, which allows us to uncover degeneracies between the physical parameters of the explosion. To compare GRB 120521C to other high-redshift bursts in a uniform manner we re-fit all available afterglow data for the two other bursts at z ≳ 6 with radio detections (GRBs 050904 and 090423). We find a jet break at t {sub jet} ≈ 15 d for GRB 090423, in contrast to previous work. Based on these three events, we find that γ-ray bursts (GRBs) at z ≳ 6 appear to explode in constant-density environments, and exhibit a wide range of energies and densities that span the range inferred for lower redshift bursts. On the other hand, we find a hint for narrower jets in the z ≳ 6 bursts, potentially indicating a larger true event rate at these redshifts. Overall, our results indicate that long GRBs share a common progenitor population at least to z ∼ 8.

  19. High Energy Density Laboratory Astrophysics

    CERN Document Server

    Lebedev, Sergey V

    2007-01-01

    During the past decade, research teams around the world have developed astrophysics-relevant research utilizing high energy-density facilities such as intense lasers and z-pinches. Every two years, at the International conference on High Energy Density Laboratory Astrophysics, scientists interested in this emerging field discuss the progress in topics covering: - Stellar evolution, stellar envelopes, opacities, radiation transport - Planetary Interiors, high-pressure EOS, dense plasma atomic physics - Supernovae, gamma-ray bursts, exploding systems, strong shocks, turbulent mixing - Supernova remnants, shock processing, radiative shocks - Astrophysical jets, high-Mach-number flows, magnetized radiative jets, magnetic reconnection - Compact object accretion disks, x-ray photoionized plasmas - Ultrastrong fields, particle acceleration, collisionless shocks. These proceedings cover many of the invited and contributed papers presented at the 6th International Conference on High Energy Density Laboratory Astrophys...

  20. The bright and choked gamma-ray burst contribution to the IceCube and ANTARES low-energy excess

    Science.gov (United States)

    Denton, Peter B.; Tamborra, Irene

    2018-04-01

    The increasing statistics of the high-energy neutrino flux observed by the IceCube Observatory points towards an excess of events above the atmospheric neutrino background in the 30–400 TeV energy range. Such an excess is compatible with the findings of the ANTARES Telescope and it would naturally imply the possibility that more than one source class contributes to the observed flux. Electromagnetically hidden sources have been invoked to interpret this excess of events at low energies. By adopting a unified model for the electromagnetically bright and choked gamma-ray bursts and taking into account particle acceleration at the internal and collimation shock radii, we discuss whether bright and choked bursts are viable candidates. Our findings suggest that, although producing a copious neutrino flux, choked and bright astrophysical jets cannot be the dominant sources of the excess of neutrino events. A fine tuning of the model parameters or distinct scenarios for choked jets should be invoked in order to explain the low-energy neutrino data of IceCube and ANTARES.

  1. Gamma-ray bursts from stellar remnants - Probing the universe at high redshift

    NARCIS (Netherlands)

    Wijers, R.A.M.J.; Bloom, J.S.; Bagla, J.S.; Natarajan, P.

    1998-01-01

    A gamma-ray burst (GRB) releases an amount of energy similar to that of a supernova explosion, which combined with its rapid variability suggests an origin related to neutron stars or black holes. Since these compact stellar remnants form from the most massive stars not long after their birth, GRBs

  2. High spectral resolution studies of gamma ray bursts on new missions

    International Nuclear Information System (INIS)

    Desai, U. D.; Acuna, M. H.; Cline, T. L.; Dennis, B. R.; Orwig, L. E.; Trombka, J. I.; Starr, R. D.

    1996-01-01

    Two new missions will be launched in 1996 and 1997, each carrying X-ray and gamma ray detectors capable of high spectral resolution at room temperature. The Argentine Satelite de Aplicaciones Cientificas (SAC-B) and the Small Spacecraft Technology Initiative (SSTI) Clark missions will each carry several arrays of X-ray detectors primarily intended for the study of solar flares and gamma-ray bursts. Arrays of small (1 cm 2 ) cadmium zinc telluride (CZT) units will provide x-ray measurements in the 10 to 80 keV range with an energy resolution of ≅6 keV. Arrays of both silicon avalanche photodiodes (APD) and P-intrinsic-N (PIN) photodiodes (for the SAC-B mission only) will provide energy coverage from 2-25 keV with ≅1 keV resolution. For SAC-B, higher energy spectral data covering the 30-300 keV energy range will be provided by CsI(Tl) scintillators coupled to silicon APDs, resulting in similar resolution but greater simplicity relative to conventional CsI/PMT systems. Because of problems with the Pegasus launch vehicle, the launch of SAC-B has been delayed until 1997. The launch of the SSTI Clark mission is scheduled for June 1996

  3. The high energy astronomy observatories

    Science.gov (United States)

    Neighbors, A. K.; Doolittle, R. F.; Halpers, R. E.

    1977-01-01

    The forthcoming NASA project of orbiting High Energy Astronomy Observatories (HEAO's) designed to probe the universe by tracing celestial radiations and particles is outlined. Solutions to engineering problems concerning HEAO's which are integrated, yet built to function independently are discussed, including the onboard digital processor, mirror assembly and the thermal shield. The principle of maximal efficiency with minimal cost and the potential capability of the project to provide explanations to black holes, pulsars and gamma-ray bursts are also stressed. The first satellite is scheduled for launch in April 1977.

  4. High Energy $\

    CERN Multimedia

    2002-01-01

    This experiment is a high statistics exposure of BEBC filled with hydrogen to both @n and &bar.@n beams. The principal physics aims are : \\item a) The study of the production of charmed mesons and baryons using fully constrained events. \\end{enumerate} b) The study of neutral current interactions on the free proton. \\item c) Measurement of the cross-sections for production of exclusive final state N* and @D resonances. \\item d) Studies of hadronic final states in charged and neutral current reactions. \\item e) Measurement of inclusive charged current cross-sections and structure functions. \\end{enumerate}\\\\ \\\\ The neutrino flux is determined by monitoring the flux of muons in the neutrino shield. The Internal Picket Fence and External Muon Identifier of BEBC are essential parts of the experiment. High resolution cameras are used to search for visible decays of short-lived particles.

  5. Very high-frequency gravitational waves from magnetars and gamma-ray bursts

    Science.gov (United States)

    Wen, Hao; Li, Fang-Yu; Li, Jin; Fang, Zhen-Yun; Beckwith, Andrew

    2017-12-01

    Extremely powerful astrophysical electromagnetic (EM) systems could be possible sources of high-frequency gravitational waves (HFGWs). Here, based on properties of magnetars and gamma-ray bursts (GRBs), we address “Gamma-HFGWs” (with very high-frequency around 1020 Hz) caused by ultra-strong EM radiation (in the radiation-dominated phase of GRB fireballs) interacting with super-high magnetar surface magnetic fields (˜1011 T). By certain parameters of distance and power, the Gamma-HFGWs would have far field energy density Ω gw around 10-6, and they would cause perturbed signal EM waves of ˜10-20 W/m2 in a proposed HFGW detection system based on the EM response to GWs. Specially, Gamma-HFGWs would possess distinctive envelopes with characteristic shapes depending on the particular structures of surface magnetic fields of magnetars, which could be exclusive features helpful to distinguish them from background noise. Results obtained suggest that magnetars could be involved in possible astrophysical EM sources of GWs in the very high-frequency band, and Gamma-HFGWs could be potential targets for observations in the future. Supported by National Natural Science Foundation of China (11605015, 11375279, 11205254, 11647307) and the Fundamental Research Funds for the Central Universities (106112017CDJXY300003, 106112017CDJXFLX0014)

  6. High energy

    International Nuclear Information System (INIS)

    Bonner, B.E.; Roberts, J.B. Jr.

    1993-01-01

    We report here on progress made for the period from December 1, 1992 (the date of submission of our latest progress report) to November 30, 1993 for DOE Grant No. DE-FG05-92ER40717. The new results from the SMC experiment have generated a buzz of theoretical activity. Our involvement with the D0 experiment and the upgrade has increased substantially during the past two years so that we now have six people heavily committed and making what can only be described as a large and disproportionate impact on D0 physics output. Some of the new developments made here at Rice in Neural Network and Probability Density Estimation techniques for data analysis promise to have applications both in D0 and beyond. We report a load of new results from our high-p t jet photoproduction experiment. In addition we have been working on KTeV, albeit without having adequate funding for this work. Progress on the theoretical front has been nothing short of amazing, as is reported herein. In a grand lecture tour during this sabbatical year, Paul Stevenson has already reported his breakthroughs at ten institutions, including CERN, Oxford, Cambridge, Rutherford Lab, Imperial College, and Durham University. The group at Rice University has had an exceptionally productive year and we are justifiably proud of the progress which is reported here

  7. Ultrahigh energy neutrino afterglows of nearby long duration gamma-ray bursts

    Science.gov (United States)

    Thomas, Jessymol K.; Moharana, Reetanjali; Razzaque, Soebur

    2017-11-01

    Detection of ultrahigh energy (UHE, ≳1 PeV ) neutrinos from astrophysical sources will be a major advancement in identifying and understanding the sources of UHE cosmic rays (CRs) in nature. Long duration gamma-ray burst (GRB) blast waves have been considered as potential acceleration sites of UHECRs. These CRs are expected to interact with GRB afterglow photons, which are synchrotron radiation from relativistic electrons coaccelerated with CRs in the blast wave, and naturally produce UHE neutrinos. Fluxes of these neutrinos are uncertain, however, and crucially depend on the observed afterglow modeling. We have selected a sample of 23 long duration GRBs within redshift 0.5 for which adequate electromagnetic afterglow data are available and which could produce high flux of UHE afterglow neutrinos, being nearby. We fit optical, x-ray, and γ -ray afterglow data with an adiabatic blast wave model in a constant density interstellar medium and in a wind environment where the density of the wind decreases as the inverse square of the radius from the center of the GRB. The blast wave model parameters extracted from these fits are then used for calculating UHECR acceleration and p γ interactions to produce UHE neutrino fluxes from these GRBs. We have also explored the detectability of these neutrinos by currently running and upcoming large area neutrino detectors, such as the Pierre Auger Observatory, IceCube Gen-2, and KM3NeT observatories. We find that our realistic flux models from nearby GRBs will be unconstrained in the foreseeable future.

  8. THE PEAK ENERGY-DURATION CORRELATION AND POSSIBLE IMPLICATIONS ON GAMMA RAY BURST PROGENITOR

    Directory of Open Access Journals (Sweden)

    Heon-Young Chang

    2006-09-01

    Full Text Available We investigate the correlation between the peak energy and the burst duration using available long GRB data with known redshift, whose circumburst medium type has been suggested via afterglow light curve modeling. We find that the peak energy and the burst duration of the observed GRBs are correlated both in the observer frame and in the GRB rest frame. For our total sample we obtain, for instance, the Spearman rank-order correlation values sim 0.75 and sim 0.65 with the chance probabilities P=1.0 times 10^{-3} and P=6.0 times 10^{-3} in the observer frame and in the GRB rest frame, respectively. We note that taking the effects of the expanding universe into account reduces the value a bit. We further attempt to separate our GRB sample into the ``ISM'' GRBs and the ``WIND'' GRBs according to environment models inferred from the afterglow light curves and apply statistical tests, as one may expect that clues on the progenitor of GRBs can be deduced directly from prompt emission properties other than from the ambient environment surrounding GRBs. We find that two subsamples of GRBs show different correlation coefficients. That is, the Spearman rank-order correlation are sim 0.65 and sim 0.57 for the ``ISM'' GRBs and ``WIND'' GRBs, respectively, after taking the effects of the expanding universe into account. It is not yet, however, statistically very much significant that the GRBS in two types of circumburst media show statistically characteristic behaviors, from which one may conclude that all the long bursts are not originated from a single progenitor population. A larger size of data is required to increase the statistical significance.

  9. Phase change based cooling for high burst mode heat loads with temperature regulation above the phase change temperature

    Science.gov (United States)

    The United States of America as represented by the United States Department of Energy

    2009-12-15

    An apparatus and method for transferring thermal energy from a heat load is disclosed. In particular, use of a phase change material and specific flow designs enables cooling with temperature regulation well above the fusion temperature of the phase change material for medium and high heat loads from devices operated intermittently (in burst mode). Exemplary heat loads include burst mode lasers and laser diodes, flight avionics, and high power space instruments. Thermal energy is transferred from the heat load to liquid phase change material from a phase change material reservoir. The liquid phase change material is split into two flows. Thermal energy is transferred from the first flow via a phase change material heat sink. The second flow bypasses the phase change material heat sink and joins with liquid phase change material exiting from the phase change material heat sink. The combined liquid phase change material is returned to the liquid phase change material reservoir. The ratio of bypass flow to flow into the phase change material heat sink can be varied to adjust the temperature of the liquid phase change material returned to the liquid phase change material reservoir. Varying the flowrate and temperature of the liquid phase change material presented to the heat load determines the magnitude of thermal energy transferred from the heat load.

  10. Energy input and response from prompt and early optical afterglow emission in gamma-ray bursts.

    Science.gov (United States)

    Vestrand, W T; Wren, J A; Wozniak, P R; Aptekar, R; Golentskii, S; Pal'shin, V; Sakamoto, T; White, R R; Evans, S; Casperson, D; Fenimore, E

    2006-07-13

    The taxonomy of optical emission detected during the critical first few minutes after the onset of a gamma-ray burst (GRB) defines two broad classes: prompt optical emission correlated with prompt gamma-ray emission, and early optical afterglow emission uncorrelated with the gamma-ray emission. The standard theoretical interpretation attributes prompt emission to internal shocks in the ultra-relativistic outflow generated by the internal engine; early afterglow emission is attributed to shocks generated by interaction with the surrounding medium. Here we report on observations of a bright GRB that, for the first time, clearly show the temporal relationship and relative strength of the two optical components. The observations indicate that early afterglow emission can be understood as reverberation of the energy input measured by prompt emission. Measurements of the early afterglow reverberations therefore probe the structure of the environment around the burst, whereas the subsequent response to late-time impulsive energy releases reveals how earlier flaring episodes have altered the jet and environment parameters. Many GRBs are generated by the death of massive stars that were born and died before the Universe was ten per cent of its current age, so GRB afterglow reverberations provide clues about the environments around some of the first stars.

  11. High spectral resolution measurements of a solar flare hard X-ray burst

    International Nuclear Information System (INIS)

    Lin, R.P.; Schwartz, R.A.; NASA, Goddard Space Flight Center, Greenbelt, MD)

    1987-01-01

    Observations are reported of an intense solar flare hard X-ray burst on June 27, 1980, made with a balloon-borne array of liquid nitrogen-cooled Ge detector which provided unprecedented spectral resolution (no more than 1 keV FWHM). The hard X-ray spectra throughout the impulsive phase burst fitted well to a double power-law form, and emission from an isothermal 0.1-1 billion K plasma can be specifically excluded. The temporal variations of the spectrum indicate that the hard X-ray burst is made up of two superposed components: individual spikes lasting about 3-15 sec, which have a hard spectrum and a break energy of 30-65 keV; and a slowly varying component characterized by a soft spectrum with a constant low-energy slope and a break energy which increases from 25 kev to at least 100 keV through the event. The double power-law shape indicates that DC electric field acceleration, similar to that occurring in the earth's auroral zone, may be the source of the energetic electrons which produce the hard X-ray emission. 39 references

  12. Cosmological model-independent Gamma-ray bursts calibration and its cosmological constraint to dark energy

    International Nuclear Information System (INIS)

    Xu, Lixin

    2012-01-01

    As so far, the redshift of Gamma-ray bursts (GRBs) can extend to z ∼ 8 which makes it as a complementary probe of dark energy to supernova Ia (SN Ia). However, the calibration of GRBs is still a big challenge when they are used to constrain cosmological models. Though, the absolute magnitude of GRBs is still unknown, the slopes of GRBs correlations can be used as a useful constraint to dark energy in a completely cosmological model independent way. In this paper, we follow Wang's model-independent distance measurement method and calculate their values by using 109 GRBs events via the so-called Amati relation. Then, we use the obtained model-independent distances to constrain ΛCDM model as an example

  13. Burst annealing of high temperature GaAs solar cells

    Science.gov (United States)

    Brothers, P. R.; Horne, W. E.

    1991-01-01

    One of the major limitations of solar cells in space power systems is their vulnerability to radiation damage. One solution to this problem is to periodically heat the cells to anneal the radiation damage. Annealing was demonstrated with silicon cells. The obstacle to annealing of GaAs cells was their susceptibility to thermal damage at the temperatures required to completely anneal the radiation damage. GaAs cells with high temperature contacts and encapsulation were developed. The cells tested are designed for concentrator use at 30 suns AMO. The circular active area is 2.5 mm in diameter for an area of 0.05 sq cm. Typical one sun AMO efficiency of these cells is over 18 percent. The cells were demonstrated to be resistant to damage after thermal excursions in excess of 600 C. This high temperature tolerance should allow these cells to survive the annealing of radiation damage. A limited set of experiments were devised to investigate the feasibility of annealing these high temperature cells. The effect of repeated cycles of electron and proton irradiation was tested. The damage mechanisms were analyzed. Limitations in annealing recovery suggested improvements in cell design for more complete recovery. These preliminary experiments also indicate the need for further study to isolate damage mechanisms. The primary objective of the experiments was to demonstrate and quantify the annealing behavior of high temperature GaAs cells. Secondary objectives were to measure the radiation degradation and to determine the effect of repeated irradiation and anneal cycles.

  14. Burst annealing of high temperature GaAs solar cells

    International Nuclear Information System (INIS)

    Brothers, P.R.; Horne, W.E.

    1991-01-01

    One of the major limitations of solar cells in space power systems is their vulnerability to radiation damage. One solution to this problem is to periodically heat the cells to anneal the radiation damage. Annealing was demonstrated with silicon cells. The obstacle to annealing of GaAs cells was their susceptibility to thermal damage at the temperatures required to completely anneal the radiation damage. GaAs cells with high temperature contacts and encapsulation were developed. The cells tested are designed for concentrator use at 30 suns AMO. The circular active area is 2.5 mm in diameter for an area of 0.05 sq cm. Typical one sun AMO efficiency of these cells is over 18 percent. The cells were demonstrated to be resistant to damage after thermal excursions in excess of 600 degree C. This high temperature tolerance should allow these cells to survive the annealing of radiation damage. A limited set of experiments were devised to investigate the feasibility of annealing these high temperature cells. The effect of repeated cycles of electron and proton irradiation was tested. The damage mechanisms were analyzed. Limitations in annealing recovery suggested improvements in cell design for more complete recovery. These preliminary experiments also indicate the need for further study to isolate damage mechanisms. The primary objective of the experiments was to demonstrate and quantify the annealing behavior of high temperature GaAs cells. Secondary objectives were to measure the radiation degradation and to determine the effect of repeated irradiation and anneal cycles

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

    International Nuclear Information System (INIS)

    Eichler, David; Pohl, Martin

    2011-01-01

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

  16. Correlation between peak energy and Fourier power density spectrum slope in gamma-ray bursts

    Science.gov (United States)

    Dichiara, S.; Guidorzi, C.; Amati, L.; Frontera, F.; Margutti, R.

    2016-05-01

    Context. The origin of the gamma-ray burst (GRB) prompt emission still defies explanation, in spite of recent progress made, for example, on the occasional presence of a thermal component in the spectrum along with the ubiquitous non-thermal component that is modelled with a Band function. The combination of finite duration and aperiodic modulations make GRBs hard to characterise temporally. Although correlations between GRB luminosity and spectral hardness on one side and time variability on the other side have long been known, the loose and often arbitrary definition of the latter makes the interpretation uncertain. Aims: We characterise the temporal variability in an objective way and search for a connection with rest-frame spectral properties for a number of well-observed GRBs. Methods: We studied the individual power density spectra (PDS) of 123 long GRBs with measured redshift, rest-frame peak energy Ep,I of the time-averaged ν Fν spectrum, and well-constrained PDS slope α detected with Swift, Fermi and past spacecraft. The PDS were modelled with a power law either with or without a break adopting a Bayesian Markov chain Monte Carlo technique. Results: We find a highly significant Ep,I-α anti-correlation. The null hypothesis probability is ~10-9. Conclusions: In the framework of the internal shock synchrotron model, the Ep,I-α anti-correlation can hardly be reconciled with the predicted Ep,I ∝ Γ-2, unless either variable microphysical parameters of the shocks or continual electron acceleration are assumed. Alternatively, in the context of models based on magnetic reconnection, the PDS slope and Ep,I are linked to the ejecta magnetisation at the dissipation site, so that more magnetised outflows would produce more variable GRB light curves at short timescales (≲1 s), shallower PDS, and higher values of Ep,I. Full Table 1 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc

  17. High autumn temperature delays spring bud burst in boreal trees, counterbalancing the effect of climatic warming

    Energy Technology Data Exchange (ETDEWEB)

    Heide, O. M. [Agricultural Univesity of Norway, Department of Biology and Nature Conservation, As (Norway)

    2003-09-01

    The effect of temperature during short-day dormancy induction on the duration and stability of bud dormancy was examined in three boreal tree species (2 birches and 1 alder) grown in a controlled environment. The phenology of the latitudinal range of birch populations, and the relationship between spring bud burst and autumn and spring temperatures were also studied. Results showed that during short-day dormancy induction in the autumn high temperatures delayed bud burst in the following spring in both controlled and natural environments. It is suggested that this response to higher autumn temperatures may be a manifestation of a general synergism between high temperature and short-day photoperiodic processes, and may be an adaptive mechanism common to boreal trees. It is further conjectured that this mechanism may be important in counterbalancing the potentially adverse effects of higher winter temperatures on dormancy stability of boreal trees during climate warming. 23 refs., 2 tabs., 4 figs.

  18. High autumn temperature delays spring bud burst in boreal trees, counterbalancing the effect of climatic warming.

    Science.gov (United States)

    Heide, O M

    2003-09-01

    The effect of temperature during short-day (SD) dormancy induction was examined in three boreal tree species in a controlled environment. Saplings of Betula pendula Roth, B. pubescens Ehrh. and Alnus glutinosa (L.) Moench. were exposed to 5 weeks of 10-h SD induction at 9, 15 and 21 degrees C followed by chilling at 5 degrees C for 40, 70, 100 and 130 days and subsequent forcing at 15 degrees C in a 24-h photoperiod for 60 days. In all species and with all chilling periods, high temperature during SD dormancy induction significantly delayed bud burst during subsequent flushing at 15 degrees C. In A. glutinosa, high temperature during SD dormancy induction also significantly increased the chilling requirement for dormancy release. Field experiments at 60 degrees N with a range of latitudinal birch populations revealed a highly significant correlation between autumn temperature and days to bud burst in the subsequent spring. September temperature alone explained 20% of the variation between years in time of bud burst. In birch populations from 69 and 71 degrees N, which ceased growing and shed their leaves in August when the mean temperature was 15 degrees C, bud burst occurred later than expected compared with lower latitude populations (56 degrees N) in which dormancy induction took place more than 2 months later at a mean temperature of about 6 degrees C. It is concluded that this autumn temperature response may be important for counterbalancing the potentially adverse effects of higher winter temperatures on dormancy stability of boreal trees during climate warming.

  19. Solar X-ray bursts

    International Nuclear Information System (INIS)

    Urnov, A.M.

    1980-01-01

    In the popular form the consideration is given to the modern state tasks and results of X-ray spectrometry of solar bursts. The operation of X-ray spectroheliograph is described. Results of spectral and polarization measurings of X-ray radiation of one powerful solar burst are presented. The conclusion has been drawn that in the process of burst development three characteristic stages may be distingwished: 1) the initial phase; just in this period processes which lead to observed consequences-electromagnetic and corpuscular radiation are born; 2) the impulse phase, or the phase of maximum, is characterised by sharp increase of radiation flux. During this phase the main energy content emanates and some volumes of plasma warm up to high temperatures; 3) the phase of burst damping, during which plasma cools and reverts to the initial condition

  20. Observations of cosmic gamma ray bursts with WATCH on EURECA

    DEFF Research Database (Denmark)

    Brandt, Søren; Lund, N.; Castro-Tirado, A. J.

    1995-01-01

    19 Cosmic Gamma-Ray Bursts were detected by the WATCH wide field X-ray monitor during the 11 months flight of EURECA. The identification of the bursts were complicated by a high frequency of background of events caused by high energy cosmic ray interactions in the detector and by low energy, trap...

  1. High energy transients: The millisecond domain

    Science.gov (United States)

    Rao, A. R.

    2018-02-01

    The search for high energy transients in the millisecond domain has come to the focus in recent times due to the detection of gravitational wave events and the identification of fast radio bursts as cosmological sources. Here we highlight the sensitivity limitations in the currently operating hard X-ray telescopes and give some details of the search for millisecond events in the AstroSat CZT Imager data.

  2. Computer aided method of low voltage power distribution networks protection system against lightning and electromagnetic pulse generated by high altitude nuclear burst

    International Nuclear Information System (INIS)

    Laroubine, J.

    1989-01-01

    The lightning creates an electromagnetic field which produces a slow duration and high energy pulse of current on low voltage power distribution networks. On the other hand an high altitude nuclear burst generates an electromagnetic pulse which causes fast and intense interferences. We describe here the specifications of a passive filter that can reject these interferences. We used a computer aided method of simulation to create a prototype. Experimental results confirm the validity of the model used for simulation [fr

  3. High energy astrophysics an introduction

    CERN Document Server

    Courvoisier, Thierry J -L

    2013-01-01

    High-energy astrophysics has unveiled a Universe very different from that only known from optical observations. It has revealed many types of objects in which typical variability timescales are as short as years, months, days, and hours (in quasars, X-ray binaries, and other objects), and even down to milli-seconds in gamma ray bursts. The sources of energy that are encountered are only very seldom nuclear fusion, and most of the time gravitation, a paradox when one thinks that gravitation is, by many orders of magnitude, the weakest of the fundamental interactions. The understanding of these objects' physical conditions and the processes revealed by high-energy astrophysics in the last decades is nowadays part of astrophysicists' culture, even of those active in other domains of astronomy. This book evolved from lectures given to master and PhD students at the University of Geneva since the early 1990s. It aims at providing astronomers and physicists intending to be active in high-energy astrophysics a broad...

  4. Why high energy physics

    International Nuclear Information System (INIS)

    Diddens, A.N.; Van de Walle, R.T.

    1981-01-01

    An argument is presented for high energy physics from the point of view of the practitioners. Three different angles are presented: The cultural consequence and scientific significance of practising high energy physics, the potential application of the results and the discovery of high energy physics, and the technical spin-offs from the techniques and methods used in high energy physics. (C.F.)

  5. Thermonuclear model for high energy transients

    International Nuclear Information System (INIS)

    Woosley, S.E.

    1982-01-01

    The thermonuclear model for x- and γ-ray bursts is discussed. Different regimes of nuclear burning are reviewed, each appropriate to a given range of (steady state) accretion rate. Accretion rates in the range 10 -14 to 10 -8 Msub solar y -1 all appear capable of producing x-ray transients of various durations and intervals. Modifications introduced by radiatively driven mass loss, the thermal inertia of the envelope, different burning mechanisms, and two-dimensional considerations are discussed as are difficulties encountered when the thermonuclear model is confronted with observations of rapidly recurrent bursts (less than or equal to 10 min), and super-Eddington luminosities and temperatures. Results from a numerical simulation of a combined hydrogen-helium runaway initiated at pycnonuclear density are presented for the first time. The thermonuclear model for γ-ray bursts is also reviewed and updated, particularly with regard to the breakdown of the steady state hypothesis employed in previous work. Solely on the basis of nuclear instability, γ-ray bursts of various types appear possible for a very broad variety of accretion rates (approx. 10 -17 to approx. 10 -11 Msub solar y -1 ) although other considerations may restrict this range. The thermonuclear model appears capable of yielding a great diversity of high energy transient phenomena for various accretion rates, magnetic field configurations, and neutron star envelope histories

  6. High energy astrophysics. An introduction

    Energy Technology Data Exchange (ETDEWEB)

    Courvoisier, Thierry J.L. [Geneva Univ., Versoix (Switzerland). ISDC, Data Centre for Astrophysics

    2013-07-01

    Based on observational examples this book reveals and explains high-energy astrophysical processes. Presents the theory of astrophysical processes in a didactic approach by deriving equations step by step. With several attractive astronomical pictures. High-energy astrophysics has unveiled a Universe very different from that only known from optical observations. It has revealed many types of objects in which typical variability timescales are as short as years, months, days, and hours (in quasars, X-ray binaries, and other objects), and even down to milli-seconds in gamma ray bursts. The sources of energy that are encountered are only very seldom nuclear fusion, and most of the time gravitation, a paradox when one thinks that gravitation is, by many orders of magnitude, the weakest of the fundamental interactions. The understanding of these objects' physical conditions and the processes revealed by high-energy astrophysics in the last decades is nowadays part of astrophysicists' culture, even of those active in other domains of astronomy. This book evolved from lectures given to master and PhD students at the University of Geneva since the early 1990s. It aims at providing astronomers and physicists intending to be active in high-energy astrophysics a broad basis on which they should be able to build the more specific knowledge they will need. While in the first part of the book the physical processes are described and derived in detail, the second part studies astrophysical objects in which high-energy astrophysics plays a crucial role. This two-pronged approach will help students recognise physical processes by their observational signatures in contexts that may differ widely from those presented here.

  7. 25-Gbit/s burst-mode optical receiver using high-speed avalanche photodiode for 100-Gbit/s optical packet switching.

    Science.gov (United States)

    Nada, Masahiro; Nakamura, Makoto; Matsuzaki, Hideaki

    2014-01-13

    25-Gbit/s error-free operation of an optical receiver is successfully demonstrated against burst-mode optical input signals without preambles. The receiver, with a high-sensitivity avalanche photodiode and burst-mode transimpedance amplifier, exhibits sufficient receiver sensitivity and an extremely quick response suitable for burst-mode operation in 100-Gbit/s optical packet switching.

  8. Relativistic motion in gamma-ray bursts

    International Nuclear Information System (INIS)

    Krolik, J.H.; Pier, E.A.

    1991-01-01

    Three fundamental problems affect models of gamma-ray bursts, i.e., the energy source, the ability of high-energy photons to escape the radiation region, and the comparative weakness of X-ray emission. It is indicated that relativistic bulk motion of the gamma-ray-emitting plasma generically provides a solution to all three of these problems. Results show that, if the plasma that produces gamma-ray bursts has a bulk relativistic velocity with Lorentz factor gamma of about 10, several of the most troubling problems having to do with gamma-ray bursts are solved. 42 refs

  9. Ultra-high energy signals from Hercules X-1

    International Nuclear Information System (INIS)

    Haines, T.J.; Alexandreas, D.E.; Allen, R.C.

    1988-01-01

    The expectation that high-energy neutrinos are emitted from astrophysical objects depends strongly on the observation of those objects in gamma-rays, especially at TeV and PeV energies. A search for bursts of gamma-ray events from Hercules X-1 at energies above 50 TeV yielded two significant bursts, both occurring on UT 24 July 1986. The events were pulsed with a period of 1.23568 s, significantly different from estimates of the pulsar period at that time. The probability that the signal is a random background fluctuation is about 2 /times/ 10/sup /minus/5/, not including the fact that there were two other independent observations of the source at nearly the same time. The muon content of the burst events is anomalous when compared with expectations of gamma-ray showers, perhaps signalling the onset of new physics at these energies. 9 refs., 4 figs., 1 tab

  10. High speed cinematography of the initial break-point of latex condoms during the air burst test.

    Science.gov (United States)

    Stube, R; Voeller, B; Davidhazy, A

    1990-06-01

    High speed cinematography of latex condoms inflated to burst under standard (ISO) conditions reveals that rupture of the condom typically is initiated at a small focal point on the shank of the condom and then rapidly propagates throughout the condom's surface, often ending with partial or full severance of the condom at its point of attachment to the air burst instrument. This sequence of events is the reverse of that sometimes hypothesized to occur, where initiation of burst was considered to begin at the attachment point and to constitute a testing method artifact. This hypothesis of breakage at the attachment point, if true, would diminish the value of the air burst test as a standard for assessing manufacturing quality control as well as for condom strength measurements and comparisons.

  11. Utilizing the Updated Gamma-Ray Bursts and Type Ia Supernovae to Constrain the Cardassian Expansion Model and Dark Energy

    Directory of Open Access Journals (Sweden)

    Jun-Jie Wei

    2015-01-01

    Full Text Available We update gamma-ray burst (GRB luminosity relations among certain spectral and light-curve features with 139 GRBs. The distance modulus of 82 GRBs at z>1.4 can be calibrated with the sample at z≤1.4 by using the cubic spline interpolation method from the Union2.1 Type Ia supernovae (SNe Ia set. We investigate the joint constraints on the Cardassian expansion model and dark energy with 580 Union2.1 SNe Ia sample (z<1.4 and 82 calibrated GRBs’ data (1.4high-z GRBs to 580 SNe Ia significantly improves the constraint on Ωm-ΩΛ plane. In the Cardassian expansion model, the best fit is Ωm=0.24-0.15+0.15 and n=0.16-0.52+0.30  (1σ, which is consistent with the ΛCDM cosmology (n=0 in the 1σ confidence region. We also discuss two dark energy models in which the equation of state w(z is parameterized as w(z=w0 and w(z=w0+w1z/(1+z, respectively. Based on our analysis, we see that our universe at higher redshift up to z=8.2 is consistent with the concordance model within 1σ confidence level.

  12. Observations of short gamma-ray bursts.

    Science.gov (United States)

    Fox, Derek B; Roming, Peter W A

    2007-05-15

    We review recent observations of short-hard gamma-ray bursts and their afterglows. The launch and successful ongoing operations of the Swift satellite, along with several localizations from the High-Energy Transient Explorer mission, have provoked a revolution in short-burst studies: first, by quickly providing high-quality positions to observers; and second, via rapid and sustained observations from the Swift satellite itself. We make a complete accounting of Swift-era short-burst localizations and proposed host galaxies, and discuss the implications of these observations for the distances, energetics and environments of short bursts, and the nature of their progenitors. We then review the physical modelling of short-burst afterglows: while the simplest afterglow models are inadequate to explain the observations, there have been several notable successes. Finally, we address the case of an unusual burst that threatens to upset the simple picture in which long bursts are due to the deaths of massive stars, and short bursts to compact-object merger events.

  13. Low energy spectral index and Ep evolution of quasi-thermal photosphere emission of gamma-ray bursts

    International Nuclear Information System (INIS)

    Deng, Wei; Zhang, Bing

    2014-01-01

    Recent observations by the Fermi satellite suggest that a photosphere emission component is contributing to the observed spectrum of many gamma-ray bursts (GRBs). One important question is whether the photosphere component can interpret the typical 'Band' function of GRBs with a typical low energy photon spectral index α ∼ –1. We perform a detailed study of the photosphere emission spectrum by progressively introducing several physical ingredients previously not fully incorporated, including the probability distribution of the location of a dynamically evolving photosphere, superposition of emission from an equal arrival time 'volume' in a continuous wind, the evolution of optical depth of a wind with finite but evolving outer boundary, as well as the effect of different top-hat wind luminosity (L w ) profiles. By assuming a comoving blackbody spectrum emerging from the photosphere, we find that for an outflow with a constant or increasing L w , the low-energy spectrum below the peak energy (E p ), can be modified to F ν ∼ ν 1.5 (α ∼ +0.5). A softer (–1 < α < +0.5) or flat (α = –1) spectrum can be obtained during the L w decreasing phase or high-latitude-emission-dominated phase. We also study the evolution of E p as a function of wind and photosphere luminosity in this photosphere model. An E p – L tracking pattern can be reproduced if a certain positive dependence between the dimensionless entropy η and L w is introduced. However, the hard-to-soft evolution pattern cannot be reproduced unless a contrived condition is invoked. In order to interpret the Band spectrum, a more complicated photosphere model or a different energy dissipation and radiation mechanism is needed.

  14. Review of GRANAT observations of gamma-ray bursts

    DEFF Research Database (Denmark)

    Terekhov, O.; Denissenko, D.; Sunyaev, R.

    1995-01-01

    The GRANAT observatory was launched into a high apogee orbit on 1 December, 1989. Three instruments onboard GRANAT - PHEBUS, WATCH and SIGMA are able to detect gamma-ray bursts in a very broad energy range from 6 keV up to 100 MeV. Over 250 gamma-ray bursts were detected. We discuss the results...... of the observations of the time histories and spectral evolution of the detected events provided by the different instruments in different energy ranges. Short Gamma-Ray Bursts ( 2 s) events. Evidence of the existence...... of four differently behaving componenents in gamma-ray burst spectra is discussed. Statistical properties of the gamma-ray burst sources based on the 5 years of observations with (∼ 10−6 erg/cm2) sensitivity as well as the results of high sensitivity (∼ 10−8 erg/cm2) search for Gamma-Ray Bursts within...

  15. CONSTRAINTS ON VERY HIGH ENERGY EMISSION FROM GRB 130427A

    International Nuclear Information System (INIS)

    Aliu, E.; Errando, M.; Aune, T.; Barnacka, A.; Beilicke, M.; Buckley, J. H.; Bugaev, V.; Benbow, W.; Cerruti, M.; Berger, K.; Biteau, J.; Byrum, K.; Cardenzana, J. V; Dickinson, H. J.; Eisch, J. D.; Chen, X.; Ciupik, L.; Connaughton, V.; Cui, W.; Falcone, A.

    2014-01-01

    Prompt emission from the very fluent and nearby (z = 0.34) gamma-ray burst GRB 130427A was detected by several orbiting telescopes and by ground-based, wide-field-of-view optical transient monitors. Apart from the intensity and proximity of this GRB, it is exceptional due to the extremely long-lived high-energy (100 MeV to 100 GeV) gamma-ray emission, which was detected by the Large Area Telescope on the Fermi Gamma-Ray Space Telescope for ∼70 ks after the initial burst. The persistent, hard-spectrum, high-energy emission suggests that the highest-energy gamma rays may have been produced via synchrotron self-Compton processes though there is also evidence that the high-energy emission may instead be an extension of the synchrotron spectrum. VERITAS, a ground-based imaging atmospheric Cherenkov telescope array, began follow-up observations of GRB 130427A ∼71 ks (∼20 hr) after the onset of the burst. The GRB was not detected with VERITAS; however, the high elevation of the observations, coupled with the low redshift of the GRB, make VERITAS a very sensitive probe of the emission from GRB 130427A for E > 100 GeV. The non-detection and consequent upper limit derived place constraints on the synchrotron self-Compton model of high-energy gamma-ray emission from this burst

  16. Very high energy colliders

    International Nuclear Information System (INIS)

    Richter, B.

    1986-03-01

    The luminosity and energy requirements are considered for both proton colliders and electron-positron colliders. Some of the basic design equations for high energy linear electron colliders are summarized, as well as design constraints. A few examples are given of parameters for very high energy machines. 4 refs., 6 figs

  17. High energy neutron radiography

    International Nuclear Information System (INIS)

    Gavron, A.; Morley, K.; Morris, C.; Seestrom, S.; Ullmann, J.; Yates, G.; Zumbro, J.

    1996-01-01

    High-energy spallation neutron sources are now being considered in the US and elsewhere as a replacement for neutron beams produced by reactors. High-energy and high intensity neutron beams, produced by unmoderated spallation sources, open potential new vistas of neutron radiography. The authors discuss the basic advantages and disadvantages of high-energy neutron radiography, and consider some experimental results obtained at the Weapons Neutron Research (WNR) facility at Los Alamos

  18. Detection of intensity bursts using Hawkes processes: An application to high-frequency financial data

    Science.gov (United States)

    Rambaldi, Marcello; Filimonov, Vladimir; Lillo, Fabrizio

    2018-03-01

    Given a stationary point process, an intensity burst is defined as a short time period during which the number of counts is larger than the typical count rate. It might signal a local nonstationarity or the presence of an external perturbation to the system. In this paper we propose a procedure for the detection of intensity bursts within the Hawkes process framework. By using a model selection scheme we show that our procedure can be used to detect intensity bursts when both their occurrence time and their total number is unknown. Moreover, the initial time of the burst can be determined with a precision given by the typical interevent time. We apply our methodology to the midprice change in foreign exchange (FX) markets showing that these bursts are frequent and that only a relatively small fraction is associated with news arrival. We show lead-lag relations in intensity burst occurrence across different FX rates and we discuss their relation with price jumps.

  19. Gamma-Ray Bursts: Lighting Up the High-Redshift Universe

    Science.gov (United States)

    Toy, Vicki Louise

    Gamma-ray bursts (GRBs) are the most luminous events in the Universe with Egamma,iso ˜ 1048-54 erg. Leading models hypothesize that GRBs are created from inter- nal collisions within collimated and ultrarelativistic jets. The jets then shock-heat the surrounding material (e.g. interstellar medium) to create GRB afterglows. These afterglows are extremely useful probes of the Universe because long GRBs are (1) bright events that can be used as backlights for absorption studies, (2) able to probe at all redshifts massive stars exist, and (3) transient events that allow us to follow- up on the host galaxies at late times. In this thesis we study the environments of GRBs. We first explore the relationship between GRB and supernova (SN) using a nearby GRB-SN (GRB 130702A/SN 2013dx) at z = 0.145. There are only nine other GRB-SNe that were close enough to have extensive spectroscopic and photometric follow-up of the SN at late times. We create a quasi-bolometic light curve of SN 2013dx and fit an analytical equation to the quasi-bolometric light curve combined with measurements of the photospheric velocity to determine SN parameters: mass of 56Ni, kinetic energy, and ejecta mass. We examine the relationship between SN parameters and E gamma,iso for the 10 well-studied GRB-SNe, but find no correlations despite numerical simulation predictions that the mass of 56Ni should correlate with the degree of asymmetry. We then move to larger distance scales and use GRB afterglows as bright back- lights to study distant galaxies. We examine the galactic environments of Damped Lyman-alpha systems (DLAs; NHI ≥ 1020.3 cm-2 ) identified with GRB afterglows at z ˜ 2 - 6. We use late-time photometry after the GRB afterglow has faded to determine star formation rates (SFRs) from rest-frame ultraviolet measurements or spectral energy distribution (SED) models from multiband photometry. We com- pare our sample's SFRs to a sample of quasars (QSOs) DLA host galaxies. Despite the

  20. The Drift Burst Hypothesis

    OpenAIRE

    Christensen, Kim; Oomen, Roel; Renò, Roberto

    2016-01-01

    The Drift Burst Hypothesis postulates the existence of short-lived locally explosive trends in the price paths of financial assets. The recent US equity and Treasury flash crashes can be viewed as two high profile manifestations of such dynamics, but we argue that drift bursts of varying magnitude are an expected and regular occurrence in financial markets that can arise through established mechanisms such as feedback trading. At a theoretical level, we show how to build drift bursts into the...

  1. NO CORRELATION BETWEEN HOST GALAXY METALLICITY AND GAMMA-RAY ENERGY RELEASE FOR LONG-DURATION GAMMA-RAY BURSTS

    International Nuclear Information System (INIS)

    Levesque, Emily M.; Kewley, Lisa J.; Soderberg, Alicia M.; Berger, Edo

    2010-01-01

    We compare the redshifts, host galaxy metallicities, and isotropic (E γ,iso ) and beaming-corrected (E γ ) gamma-ray energy release of 16 long-duration gamma-ray bursts (LGRBs) at z γ,iso , or E γ . These results are at odds with previous theoretical and observational predictions of an inverse correlation between gamma-ray energy release and host metallicity, as well as the standard predictions of metallicity-driven wind effects in stellar evolutionary models. We consider the implications that these results have for LGRB progenitor scenarios, and discuss our current understanding of the role that metallicity plays in the production of LGRBs.

  2. RAPID, MACHINE-LEARNED RESOURCE ALLOCATION: APPLICATION TO HIGH-REDSHIFT GAMMA-RAY BURST FOLLOW-UP

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, A N; Richards, Joseph W; Butler, Nathaniel R; Bloom, Joshua S [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Long, James; Broderick, Tamara [Department of Statistics, University of California, Berkeley, CA 94720-3860 (United States)

    2012-02-20

    As the number of observed gamma-ray bursts (GRBs) continues to grow, follow-up resources need to be used more efficiently in order to maximize science output from limited telescope time. As such, it is becoming increasingly important to rapidly identify bursts of interest as soon as possible after the event, before the afterglows fade beyond detectability. Studying the most distant (highest redshift) events, for instance, remains a primary goal for many in the field. Here, we present our Random Forest Automated Triage Estimator for GRB redshifts (RATE GRB-z ) for rapid identification of high-redshift candidates using early-time metrics from the three telescopes onboard Swift. While the basic RATE methodology is generalizable to a number of resource allocation problems, here we demonstrate its utility for telescope-constrained follow-up efforts with the primary goal to identify and study high-z GRBs. For each new GRB, RATE GRB-z provides a recommendation-based on the available telescope time-of whether the event warrants additional follow-up resources. We train RATE GRB-z using a set consisting of 135 Swift bursts with known redshifts, only 18 of which are z > 4. Cross-validated performance metrics on these training data suggest that {approx}56% of high-z bursts can be captured from following up the top 20% of the ranked candidates, and {approx}84% of high-z bursts are identified after following up the top {approx}40% of candidates. We further use the method to rank 200 + Swift bursts with unknown redshifts according to their likelihood of being high-z.

  3. Analyses of High-Energy Sources with ESA Gaia

    Czech Academy of Sciences Publication Activity Database

    Hudec, R.; Šimon, Vojtěch; Hudcová, Věra

    2010-01-01

    Roč. 1248, - (2010), s. 583-584 ISSN 1551-7616. [X-ray astronomy 2009. Bologna, 07.09.2009-11.09.2009] Institutional research plan: CEZ:AV0Z10030501 Keywords : high-energy sources * gamma-ray bursts * low-dispersion spectra Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  4. High energy hadron scattering

    International Nuclear Information System (INIS)

    Johnson, R.C.

    1980-01-01

    High energy and small momentum transfer 2 'yields' 2 hadronic scattering processes are described in the physical framework of particle exchange. Particle production in high energy collisions is considered with emphasis on the features of inclusive reactions though with some remarks on exclusive processes. (U.K.)

  5. The high energy galaxy

    International Nuclear Information System (INIS)

    Cesarsky, C.J.

    1986-08-01

    The galaxy is host to a wide variety of high energy events. I review here recent results on large scale galactic phenomena: cosmic-ray origin and confinement, the connexion to ultra high energy gamma-ray emission from X-ray binaries, gamma ray and synchrotron emission in interstellar space, galactic soft and hard X-ray emission

  6. Observation of gamma-ray bursts with GINGA

    International Nuclear Information System (INIS)

    Murakami, Toshio; Fujii, Masami; Nishimura, Jun

    1989-01-01

    Gamma-ray Burst Detector System (GBD) on board the scientific satellite 'GINGA' which was launched on Feb. 5, 1987, was realized as an international cooperation between ISAS and LANL. It has recorded more than 40 Gamma-Ray Burst candidates during 20 months observation. Although many observational evidences were accumulated in past 20 years after the discovery of gamma-ray burst by LANL scientists, there are not enough evidence to determine the origin and the production mechanism of the gamma-ray burst. GBD consists of a proportional counter and a NaI scintillation counter so that it became possible to observe energy spectrum of the gamma-ray burst with high energy resolution over wide range of energy (1.5-380 keV) together with high time resolution. As the result of observation, the following facts are obtained: (1) A large fraction of observed gamma-ray bursts has a long X-ray tail after the harder part of gamma-ray emission has terminated. (2) Clear spectral absorption features with harmonic in energy was observed in some of the energy spectrum of gamma-ray bursts. These evidences support the hypothesis that the strongly magnetized neutron star is the origin of gamma-ray burst. (author)

  7. Quadri-Pulse Theta Burst Stimulation using Ultra-High Frequency Bursts - A New Protocol to Induce Changes in Cortico-Spinal Excitability in Human Motor Cortex

    DEFF Research Database (Denmark)

    Jung, Nikolai H; Gleich, Bernhard; Gattinger, Norbert

    2016-01-01

    Patterned transcranial magnetic stimulation (TMS) such as theta burst stimulation (TBS) or quadri-pulse stimulation (QPS) can induce changes in cortico-spinal excitability, commonly referred to as long-term potentiation (LTP)-like and long-term depression (LTD)-like effects in human motor cortex (M...... of sinusoidal TMS pulses elicited either a posterior-anterior (PA) or anterior-posterior (AP) directed current in M1. Motor evoked potentials (MEPs) were recorded before and after qTBS to probe changes in cortico-spinal excitability. PA-qTBS at 666 Hz caused a decrease in PA-MEP amplitudes, whereas AP...... in cortico-spinal excitability. Induced current direction in the brain appears to be relevant when qTBS targets I-wave periodicity, corroborating that high-fidelity spike timing mechanisms are critical for inducing bi-directional plasticity in human M1....

  8. Extreme Transients in the High Energy Universe

    Science.gov (United States)

    Kouveliotou, Chryssa

    2013-01-01

    The High Energy Universe is rich in diverse populations of objects spanning the entire cosmological (time)scale, from our own present-day Milky Way to the re-ionization epoch. Several of these are associated with extreme conditions irreproducible in laboratories on Earth. Their study thus sheds light on the behavior of matter under extreme conditions, such as super-strong magnetic fields (in excess of 10^14 G), high gravitational potentials (e.g., Super Massive Black Holes), very energetic collimated explosions resulting in relativistic jet flows (e.g., Gamma Ray Bursts, exceeding 10^53 ergs). In the last thirty years, my work has been mostly focused on two apparently different but potentially linked populations of such transients: magnetars (highly magnetized neutron stars) and Gamma Ray Bursts (strongly beamed emission from relativistic jets), two populations that constitute unique astrophysical laboratories, while also giving us the tools to probe matter conditions in the Universe to redshifts beyond z=10, when the first stars and galaxies were assembled. I did not make this journey alone I have either led or participated in several international collaborations studying these phenomena in multi-wavelength observations; solitary perfection is not sufficient anymore in the world of High Energy Astrophysics. I will describe this journey, present crucial observational breakthroughs, discuss key results and muse on the future of this field.

  9. A HIGH-FREQUENCY TYPE II SOLAR RADIO BURST ASSOCIATED WITH THE 2011 FEBRUARY 13 CORONAL MASS EJECTION

    Energy Technology Data Exchange (ETDEWEB)

    Cho, K.-S.; Kim, R.-S. [Korea Astronomy and Space Science Institute, Whaamdong, Yooseong-ku, Daejeon, 305-348 (Korea, Republic of); Gopalswamy, N.; Kwon, R.-Y.; Yashiro, S., E-mail: kscho@kasi.re.kr [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2013-03-10

    We examine the relationship between the high-frequency (425 MHz) type II radio burst and the associated white-light coronal mass ejection (CME) that occurred on 2011 February 13. The radio burst had a drift rate of 2.5 MHz s{sup -1}, indicating a relatively high shock speed. From SDO/AIA observations we find that a loop-like erupting front sweeps across high-density coronal loops near the start time of the burst (17:34:17 UT). The deduced distance of shock formation (0.06 Rs) from the flare center and speed of the shock (1100 km s{sup -1}) using the measured density from SDO/AIA observations are comparable to the height (0.05 Rs, from the solar surface) and speed (700 km s{sup -1}) of the CME leading edge observed by STEREO/EUVI. We conclude that the type II burst originates even in the low corona (<59 Mm or 0.08 Rs, above the solar surface) due to the fast CME shock passing through high-density loops.

  10. Implications of fast radio bursts for superconducting cosmic strings

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Yun-Wei [Institute of Astrophysics, Central China Normal University, 152 Luoyu Road, Wuhan 430079 (China); Cheng, Kwong-Sang [Department of Physics, The University of Hong Kong, Pokfulam Road, Hong Kong (China); Shiu, Gary; Tye, Henry, E-mail: yuyw@phy.ccnu.edu.cn, E-mail: hrspksc@hku.hk, E-mail: shiu@ust.hk, E-mail: iastye@ust.hk [Department of Physics and Institute for Advanced Study, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong (China)

    2014-11-01

    Highly beamed, short-duration electromagnetic bursts could be produced by superconducting cosmic string (SCS) loops oscillating in cosmic magnetic fields. We demonstrated that the basic characteristics of SCS bursts such as the electromagnetic frequency and the energy release could be consistently exhibited in the recently discovered fast radio bursts (FRBs). Moreover, it is first showed that the redshift distribution of the FRBs can also be well accounted for by the SCS burst model. Such agreements between the FRBs and SCS bursts suggest that the FRBs could originate from SCS bursts and thus they could provide an effective probe to study SCSs. The obtained values of model parameters indicate that the loops generating the FRBs have a small length scale and they are mostly formed in the radiation-dominated cosmological epoch.

  11. Implications of fast radio bursts for superconducting cosmic strings

    International Nuclear Information System (INIS)

    Yu, Yun-Wei; Cheng, Kwong-Sang; Shiu, Gary; Tye, Henry

    2014-01-01

    Highly beamed, short-duration electromagnetic bursts could be produced by superconducting cosmic string (SCS) loops oscillating in cosmic magnetic fields. We demonstrated that the basic characteristics of SCS bursts such as the electromagnetic frequency and the energy release could be consistently exhibited in the recently discovered fast radio bursts (FRBs). Moreover, it is first showed that the redshift distribution of the FRBs can also be well accounted for by the SCS burst model. Such agreements between the FRBs and SCS bursts suggest that the FRBs could originate from SCS bursts and thus they could provide an effective probe to study SCSs. The obtained values of model parameters indicate that the loops generating the FRBs have a small length scale and they are mostly formed in the radiation-dominated cosmological epoch

  12. High energy colliders

    International Nuclear Information System (INIS)

    Palmer, R.B.; Gallardo, J.C.

    1997-02-01

    The authors consider the high energy physics advantages, disadvantages and luminosity requirements of hadron (pp, p anti p), lepton (e + e - , μ + μ - ) and photon-photon colliders. Technical problems in obtaining increased energy in each type of machine are presented. The machines relative size are also discussed

  13. A strategy to unveil transient sources of ultra-high-energy cosmic rays

    Directory of Open Access Journals (Sweden)

    Takami Hajime

    2013-06-01

    Full Text Available Transient generation of ultra-high-energy cosmic rays (UHECRs has been motivated from promising candidates of UHECR sources such as gamma-ray bursts, flares of active galactic nuclei, and newly born neutron stars and magnetars. Here we propose a strategy to unveil transient sources of UHECRs from UHECR experiments. We demonstrate that the rate of UHECR bursts and/or flares is related to the apparent number density of UHECR sources, which is the number density estimated on the assumption of steady sources, and the time-profile spread of the bursts produced by cosmic magnetic fields. The apparent number density strongly depends on UHECR energies under a given rate of the bursts, which becomes observational evidence of transient sources. It is saturated at the number density of host galaxies of UHECR sources. We also derive constraints on the UHECR burst rate and/or energy budget of UHECRs per source as a function of the apparent source number density by using models of cosmic magnetic fields. In order to obtain a precise constraint of the UHECR burst rate, high event statistics above ∼ 1020 eV for evaluating the apparent source number density at the highest energies and better knowledge on cosmic magnetic fields by future observations and/or simulations to better estimate the time-profile spread of UHECR bursts are required. The estimated rate allows us to constrain transient UHECR sources by being compared with the occurrence rates of known energetic transient phenomena.

  14. Radio Afterglows of Gamma Ray Bursts

    Indian Academy of Sciences (India)

    Lekshmi Resmi

    2017-09-12

    Sep 12, 2017 ... ments on-board high energy missions like BeppoSAX1,. CGRO2, HETE3, .... rest energy of a solar mass object (GRB 080916C; Abdo et al. 2009). ..... Though the same afterglow physics applies to short bursts too, there are.

  15. Fourier Analysis of Radio Bursts Observed with Very High Time Resolution

    Czech Academy of Sciences Publication Activity Database

    Dabrowski, Bartosz Premyslaw; Karlický, Marian; Rudawy, P.

    2015-01-01

    Roč. 290, č. 1 (2015), s. 169-180 ISSN 0038-0938 Institutional support: RVO:67985815 Keywords : solar corona * flares * radio bursts Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 2.862, year: 2015

  16. High energy positron imaging

    International Nuclear Information System (INIS)

    Chen Shengzu

    2003-01-01

    The technique of High Energy Positron Imaging (HEPI) is the new development and extension of Positron Emission Tomography (PET). It consists of High Energy Collimation Imaging (HECI), Dual Head Coincidence Detection Imaging (DHCDI) and Positron Emission Tomography (PET). We describe the history of the development and the basic principle of the imaging methods of HEPI in details in this paper. Finally, the new technique of the imaging fusion, which combined the anatomical image and the functional image together are also introduced briefly

  17. High-energy detector

    Science.gov (United States)

    Bolotnikov, Aleksey E [South Setauket, NY; Camarda, Giuseppe [Farmingville, NY; Cui, Yonggang [Upton, NY; James, Ralph B [Ridge, NY

    2011-11-22

    The preferred embodiments are directed to a high-energy detector that is electrically shielded using an anode, a cathode, and a conducting shield to substantially reduce or eliminate electrically unshielded area. The anode and the cathode are disposed at opposite ends of the detector and the conducting shield substantially surrounds at least a portion of the longitudinal surface of the detector. The conducting shield extends longitudinally to the anode end of the detector and substantially surrounds at least a portion of the detector. Signals read from one or more of the anode, cathode, and conducting shield can be used to determine the number of electrons that are liberated as a result of high-energy particles impinge on the detector. A correction technique can be implemented to correct for liberated electron that become trapped to improve the energy resolution of the high-energy detectors disclosed herein.

  18. Hard burst emission from the soft gamma repeater SGR 1900+14

    NARCIS (Netherlands)

    Woods, P.M.; Kouveliotou, C.; van Paradijs, J.; Briggs, M.S.; Hurley, K.; Göğüş, E.; Preece, R.D.; Giblin, T.W.; Thompson, C.; Duncan, R.C.

    1999-01-01

    We present evidence for burst emission from SGR 1900+14 with a power-law high-energy spectrum extending beyond 500 keV. Unlike previous detections of high-energy photons during bursts from soft gamma repeaters (SGRs), these emissions are not associated with extraordinarily bright flares. Not only is

  19. Windowless microfluidic platform based on capillary burst valves for high intensity x-ray measurements

    International Nuclear Information System (INIS)

    Vig, Asger Laurberg; Enevoldsen, Nikolaj; Thilsted, Anil Haraksingh; Eriksen, Johan; Kristensen, Anders; Haldrup, Kristoffer; Feidenhans'l, Robert; Nielsen, Martin Meedom

    2009-01-01

    We propose and describe a microfluidic system for high intensity x-ray measurements. The required open access to a microfluidic channel is provided by an out-of-plane capillary burst valve (CBV). The functionality of the out-of-plane CBV is characterized with respect to the diameter of the windowless access hole, ranging from 10 to 130 μm. Maximum driving pressures from 22 to 280 mbar corresponding to refresh rates of the exposed sample from 300 Hz to 54 kHz is demonstrated. The microfluidic system is tested at beamline ID09b at the ESRF synchrotron radiation facility in Grenoble, and x-ray scattering measurements are shown to be feasible and to require only very limited amounts of sample, <1 ml/h of measurements without recapturing of sample. With small adjustments of the present chip design, scattering angles up to 30 deg. can be achieved without shadowing effects and integration on-chip mixing and spectroscopy appears straightforward.

  20. High energy nuclear excitations

    International Nuclear Information System (INIS)

    Gogny, D.; Decharge, J.

    1983-09-01

    The main purpose of this talk is to see whether a simple description of the nuclear excitations permits one to characterize some of the high energy structures recently observed. The discussion is based on the linear response to different external fields calculated using the Random Phase Approximation. For those structure in heavy ion collisions at excitation energies above 50 MeV which cannot be explained with such a simple approach, we discuss a possible mechanism for this heavy ion scattering

  1. Balloon observation of gamma-ray burst

    International Nuclear Information System (INIS)

    Nishimura, Jun; Fujii, Masami; Yamagami, Takamasa; Oda, Minoru; Ogawara, Yoshiaki

    1978-01-01

    Cosmic gamma-ray burst is an interesting high energy astrophysical phenomenon, but the burst mechanism has not been well understood. Since 1975, long duration balloon flight has been conducted to search for gamma-ray bursts and to determine the source locations. A rotating cross-modulation collimator was employed to determine the locations of sources, and four NaI(Tl) scintillation counters were employed to detect hard X-ray with energy from 20 to 200 keV. The balloon light was performed at altitude of 8.3 mb from September 28, 1977, and the observation time of 79 hours was achieved. In this experiment, the monitor counter was not mounted. The count increase was observed at 16 h 22 m 31 s JST on October 1, 1977. The event disappeared after 1 sec. The total flux is estimated to be 1.6 x 10 -6 erg/cm 2 sec at the top of the atmosphere. When this event was observed, the solar-terrestrial environment was also quiet. Thus, this event was attributed to a small gamma-ray burst. Unfortunately, the duration of the burst was so short that the position of the burst source was not able to be determined. (Yoshimori, M.)

  2. High energy radiation detector

    International Nuclear Information System (INIS)

    Vosburgh, K.G.

    1975-01-01

    The high energy radiation detector described comprises a set of closely spaced wedge reflectors. Each wedge reflector is composed of three sides forming identical isoceles triangles with a common apex and an open base forming an equilateral triangle. The length of one side of the base is less than the thickness of the coat of material sensitive to high energy radiation. The wedge reflectors reflect the light photons spreading to the rear of the coat in such a way that each reflected track is parallel to the incident track of the light photon spreading rearwards. The angle of the three isosceles triangles with a common apex is between 85 and 95 deg. The first main surface of the coat of high energy radiation sensitive material is in contact with the projecting edges of the surface of the wedge reflectors of the reflecting element [fr

  3. Theoretical high energy physics

    International Nuclear Information System (INIS)

    Lee, T.D.

    1991-01-01

    This report discusses theoretical research in high energy physics at Columbia University. Some of the research topics discussed are: quantum chromodynamics with dynamical fermions; lattice gauge theory; scattering of neutrinos by photons; atomic physics constraints on the properties of ultralight-ultraweak gauge bosons; black holes; Chern- Simons physics; S-channel theory of superconductivity; charged boson system; gluon-gluon interactions; high energy scattering in the presence of instantons; anyon physics; causality constraints on primordial magnetic manopoles; charged black holes with scalar hair; properties of Chern-Aimona-Higgs solitons; and extended inflationary universe

  4. Theoretical high energy physics

    International Nuclear Information System (INIS)

    Lee, T.D.

    1992-01-01

    This progress report discusses research by Columbia University staff in high energy physics. Some of the topics discussed are as follows: lattice gauge theory; quantum chromodynamics; parity doublets; solitons; baryon number violation; black holes; magnetic monopoles; gluon plasma; Chern-Simons theory; and the inflationary universe

  5. High energy astrophysics

    International Nuclear Information System (INIS)

    Shklorsky, I.S.

    1979-01-01

    A selected list of articles of accessible recent review articles and conference reports, wherein up-to-date summaries of various topics in the field of high energy astrophysics can be found, is presented. A special report outlines work done in the Soviet Union in this area. (Auth.)

  6. High energy battery. Hochenergiebatterie

    Energy Technology Data Exchange (ETDEWEB)

    Boehm, H.; Beyermann, G.; Bulling, M.

    1992-03-26

    In a high energy battery with a large number of individual cells in a housing with a cooling medium flowing through it, it is proposed that the cooling medium should be guided so that it only affects one or both sides of the cells thermally.

  7. High energy beam cooling

    International Nuclear Information System (INIS)

    Berger, H.; Herr, H.; Linnecar, T.; Millich, A.; Milss, F.; Rubbia, C.; Taylor, C.S.; Meer, S. van der; Zotter, B.

    1980-01-01

    The group concerned itself with the analysis of cooling systems whose purpose is to maintain the quality of the high energy beams in the SPS in spite of gas scattering, RF noise, magnet ripple and beam-beam interactions. Three types of systems were discussed. The status of these activities is discussed below. (orig.)

  8. High Energy Physics

    Science.gov (United States)

    Untitled Document [Argonne Logo] [DOE Logo] High Energy Physics Home Division ES&H Personnel Collider Physics Cosmic Frontier Cosmic Frontier Theory & Computing Detector R&D Electronic Design Mechanical Design Neutrino Physics Theoretical Physics Seminars HEP Division Seminar HEP Lunch Seminar HEP

  9. Theoretical High Energy Physics

    Energy Technology Data Exchange (ETDEWEB)

    Christ, Norman H.; Weinberg, Erick J.

    2014-07-14

    we provide reports from each of the six faculty supported by the Department of Energy High Energy Physics Theory grant at Columbia University. Each is followed by a bibliography of the references cited. A complete list of all of the publications in the 12/1/2010-04/30/2014 period resulting from research supported by this grant is provided in the following section. The final section lists the Ph.D. dissertations based on research supported by the grant that were submitted during this period.

  10. High energy dosimetry

    International Nuclear Information System (INIS)

    Ruhm, W.

    2010-01-01

    Full text: Currently, quantification of doses from high-energy radiation fields is a topical issue. This is so because high-energy neutrons play an important role for radiation exposure of air crew members and personnel outside the shielding of ion therapy facilities. In an effort to study air crew exposure from cosmic radiation in detail, two Bonner Sphere Spectrometers (BSSs) have recently been installed to measure secondary neutrons from cosmic radiation, one at the environmental research station 'Schneefernerhaus' at an altitude of 2650 m on the Zugspitze mountain, Germany, the other at the Koldewey station close to the North Pole on Spitsbergen. Based on the measured neutron fluence distributions and on fluence-to-dose conversion coefficients, mean ambient dose equivalent rate values of 75.0 ± 2.9 nSv/h and 8.7 ± 0.6 nSv/h were obtained for October 2008, respectively. Neutrons with energies above about 20 MeV contribute about 50% to dose, at 2650 m. Ambient dose equivalent rates measured by means of a standard rem counter and an extended rem counter at the Schneefernerhaus confirm this result. In order to study the response of state-of-the-art radiation instrumentation in such a high-energy radiation field, a benchmark exercise that included both measurements in and simulation of the stray neutron radiation field at the high-energy particle accelerator at GSI, Germany, were performed. This CONRAD (COordinated Network for RAdiation Dosimetry) project was funded by the European Commission, and the organizational framework was provided by the European Radiation Dosimetry Group, EURADOS. The Monte Carlo simulations of the radiation field and the experimental determination of the neutron spectra with various Bonner Sphere Spectrometers suggest the neutron fluence distributions to be very similar to those of secondary neutrons from cosmic radiation. The results of this intercomparison exercise in terms of ambient dose equivalent are also discussed

  11. Dust extinction in high-z galaxies with gamma-ray burst afterglow spectroscopy

    DEFF Research Database (Denmark)

    Elíasdóttir, Á.; Fynbo, J. P. U.; Hjorth, J.

    2009-01-01

    We report the clear detection of the 2175 Å dust absorption feature in the optical afterglow spectrum of the gamma-ray burst (GRB) GRB 070802 at a redshift of z = 2.45. This is the highest redshift for a detected 2175 Å dust bump to date, and it is the first clear detection of the 2175 Å bump...

  12. High-pass filtering and dynamic gain regulation enhance vertical bursts transmission along the mossy fiber pathway of cerebellum

    Directory of Open Access Journals (Sweden)

    Jonathan Mapelli

    2010-05-01

    Full Text Available Signal elaboration in the cerebellum mossy fiber input pathway presents controversial aspects, especially concerning gain regulation and the spot-like (rather than beam-like appearance of granular-to-molecular layer transmission. By using voltage-sensitive dye (VSD imaging in rat cerebellar slices (Mapelli et al., 2010, we found that mossy fiber bursts optimally excited the granular layer above ~50 Hz and the overlaying molecular layer above ~100 Hz, thus generating a cascade of high-pass filters. NMDA receptors enhanced transmission in the granular, while GABA-A receptors depressed transmission in both the granular and molecular layer. Burst transmission gain was controlled through a dynamic frequency-dependent involvement of these receptors. Moreover, while high-frequency transmission was enhanced along vertical lines connecting the granular to molecular layer, no high-frequency enhancement was observed along the parallel fiber axis in the molecular layer. This was probably due to the stronger effect of Purkinje cell GABA-A receptor-mediated inhibition occurring along the parallel fibers than along the granule cell axon ascending branch. The consequent amplification of burst responses along vertical transmission lines could explain the spot-like activation of Purkinje cells observed following punctuate stimulation in vivo .

  13. Energy coupling of nuclear bursts in and above the ocean surface: source region calculations and experimental validation

    International Nuclear Information System (INIS)

    Clarke, D.B.; Harben, P.E.; Rock, D.W.; White, J.W.; Piacsek, A.

    1997-01-01

    In support of the Comprehensive Test Ban, research is under way on the long range propagation of signals from nuclear explosions in deep underwater sound (SOFAR) channel. Initially our work at LLNL on signals in the source region considered explosions in or above deep ocean. We studied the variation of wave properties and source region energy coupling as a function of height or depth of burst. Initial calculations on the CALE hydrodynamics code were linked at a few hundred milliseconds to a version of NRL's weak code, NPE, which solves the nonlinear progressive wave equation. The simulation of the wave propagation was carried down to 5000 m depth and out to 10,000 m range. We have completed ten such simulations at a variety of heights and depths below the ocean surface

  14. High energy physics problems

    International Nuclear Information System (INIS)

    Arbuzov, B.A.

    1977-01-01

    Described are modern views on the particle structure and particle interactions at high energies. According to the latest data recieved, all particles can be classified in three groups: 1) strong interacting hadrons; 2) leptons, having no strong interactions; 3) photon. The particle structure is described in a quark model, and with the use of gluons. The elementary particle theory is based on the quantum field theory. The energy increase of interacting particles enables to check the main theory principles, such as conventions for causality, relativistic invariance and unitarity. Investigations of weak interactions are of great importance. The progress in this field is connected with unified gauge theories of weak and electromagnetic interactions. For weak interactions promissing are the experiments with colliding electron-proton rings. The new data, especially at higher energies, will lead to a further refinement of the nature of particles and their interactions

  15. A repeating fast radio burst.

    Science.gov (United States)

    Spitler, L G; Scholz, P; Hessels, J W T; Bogdanov, S; Brazier, A; Camilo, F; Chatterjee, S; Cordes, J M; Crawford, F; Deneva, J; Ferdman, R D; Freire, P C C; Kaspi, V M; Lazarus, P; Lynch, R; Madsen, E C; McLaughlin, M A; Patel, C; Ransom, S M; Seymour, A; Stairs, I H; Stappers, B W; van Leeuwen, J; Zhu, W W

    2016-03-10

    Fast radio bursts are millisecond-duration astronomical radio pulses of unknown physical origin that appear to come from extragalactic distances. Previous follow-up observations have failed to find additional bursts at the same dispersion measure (that is, the integrated column density of free electrons between source and telescope) and sky position as the original detections. The apparent non-repeating nature of these bursts has led to the suggestion that they originate in cataclysmic events. Here we report observations of ten additional bursts from the direction of the fast radio burst FRB 121102. These bursts have dispersion measures and sky positions consistent with the original burst. This unambiguously identifies FRB 121102 as repeating and demonstrates that its source survives the energetic events that cause the bursts. Additionally, the bursts from FRB 121102 show a wide range of spectral shapes that appear to be predominantly intrinsic to the source and which vary on timescales of minutes or less. Although there may be multiple physical origins for the population of fast radio bursts, these repeat bursts with high dispersion measure and variable spectra specifically seen from the direction of FRB 121102 support an origin in a young, highly magnetized, extragalactic neutron star.

  16. High energy nuclear physics

    International Nuclear Information System (INIS)

    Meyer, J.

    1988-01-01

    The 1988 progress report of the High Energy Nuclear Physics laboratory (Polytechnic School, France), is presented. The Laboratory research program is focused on the fundamental physics of interactions, on the new techniques for the acceleration of charged particles and on the nuclei double beta decay. The experiments are performed on the following topics: the measurement of the π 0 inclusive production and the photons production in very high energy nuclei-nuclei interactions and the nucleon stability. Concerning the experiments under construction, a new detector for LEP, the study and simulation of the hadronic showers in a calorimeter and the H1 experiment (HERA), are described. The future research programs and the published papers are listed [fr

  17. High energy medical accelerators

    International Nuclear Information System (INIS)

    Mandrillon, P.

    1990-01-01

    The treatment of tumours with charged particles, ranging from protons to 'light ions' (carbon, oxygen, neon), has many advantages, but up to now has been little used because of the absence of facilities. After the successful pioneering work carried out with accelerators built for physics research, machines dedicated to this new radiotherapy are planned or already in construction. These high energy medical accelerators are presented in this paper. (author) 15 refs.; 14 figs.; 8 tabs

  18. Theoretical high energy physics

    International Nuclear Information System (INIS)

    Lee, T.D.

    1990-05-01

    This report discusses progress on theoretical high energy physics at Columbia University in New York City. Some of the topics covered are: Chern-Simons gauge field theories; dynamical fermion QCD calculations; lattice gauge theory; the standard model of weak and electromagnetic interactions; Boson-fermion model of cuprate superconductors; S-channel theory of superconductivity and axial anomaly and its relation to spin in the parton model

  19. Probing Pre-Galactic Metal Enrichment with High-Redshift Gamma-Ray Bursts

    Science.gov (United States)

    Wang, F. Y.; Bromm, Volker; Greif, Thomas H.; Stacy, Athena; Dai, Z. G.; Loeb, Abraham; Cheng, K. S.

    2012-01-01

    We explore high-redshift gamma-ray bursts (GRBs) as promising tools to probe pre-galactic metal enrichment. We utilize the bright afterglow of a Population III (Pop III) GRB exploding in a primordial dwarf galaxy as a luminous background source, and calculate the strength of metal absorption lines that are imprinted by the first heavy elements in the intergalactic medium (IGM). To derive the GRB absorption line diagnostics, we use an existing highly resolved simulation of the formation of a first galaxy which is characterized by the onset of atomic hydrogen cooling in a halo with virial temperature approximately greater than10(exp 4) K.We explore the unusual circumburst environment inside the systems that hosted Pop III stars, modeling the density evolution with the self-similar solution for a champagne flow. For minihalos close to the cooling threshold, the circumburst density is roughly proportional to (1 + z) with values of about a few cm(exp -3). In more massive halos, corresponding to the first galaxies, the density may be larger, n approximately greater than100 cm(exp -3). The resulting afterglow fluxes are weakly dependent on redshift at a fixed observed time, and may be detectable with the James Webb Space Telescope and Very Large Array in the near-IR and radio wavebands, respectively, out to redshift z approximately greater than 20. We predict that the maximum of the afterglow emission shifts from near-IR to millimeter bands with peak fluxes from mJy to Jy at different observed times. The metal absorption line signature is expected to be detectable in the near future. GRBs are ideal tools for probing the metal enrichment in the early IGM, due to their high luminosities and featureless power-law spectra. The metals in the first galaxies produced by the first supernova (SN) explosions are likely to reside in low-ionization stages (C II, O I, Si II and Fe II). We show that, if the afterglow can be observed sufficiently early, analysis of the metal lines may

  20. Very high energy colliders

    International Nuclear Information System (INIS)

    Richter, B.

    1985-05-01

    The conclusions are relatively simple, but represent a considerable challenge to the machine builder. High luminosity is essential. We may in the future discover some new kind of high cross section physics, but all we know now indicates that the luminosity has to increase as the square of the center of mass energy. A reasonable luminosity to scale from for electron machines would be 10 33 cm -2 s -1 at a center of mass energy of 3 TeV. The required emittances in very high energy machines are small. It will be a real challenge to produce these small emittances and to maintain them during acceleration. The small emittances probably make acceleration by laser techniques easier, if such techniques will be practical at all. The beam spot sizes are very small indeed. It will be a challenge to design beam transport systems with the necessary freedom from aberration required for these small spot sizes. It would of course help if the beta functions at the collision points could be reduced. Beam power will be large - to paraphrase the old saying, ''power is money'' - and efficient acceleration systems will be required

  1. Laboratory Astrophysics Using High Energy Density Photon and Electron Beams

    CERN Document Server

    Bingham, Robert

    2005-01-01

    The development of intense laser and particle beams has opened up new opportunities to study high energy density astrophysical processes in the Laboratory. With even higher laser intensities possible in the near future vacuum polarization processes such as photon - photon scattering with or without large magnetic fields may also be experimentally observed. In this talk I will review the status of laboratory experiments using intense beans to investigate extreme astrophysical phenomena such as supernovae explosions, gamma x-ray bursts, ultra-high energy cosmic accelerators etc. Just as intense photon or electron beams can excite relativistic electron plasma waves or wakefields used in plasma acceleration, intense neutrino beams from type II supernovae can also excite wakefields or plasma waves. Other instabilities driven by intense beams relevant to perhaps x-ray bursts is the Weibel instability. Simulation results of extreme processes will also be presented.

  2. Fermi observations of high-energy gamma-ray emission from GRB 080916C.

    Science.gov (United States)

    Abdo, A A; Ackermann, M; Arimoto, M; Asano, K; Atwood, W B; Axelsson, M; Baldini, L; Ballet, J; Band, D L; Barbiellini, G; Baring, M G; Bastieri, D; Battelino, M; Baughman, B M; Bechtol, K; Bellardi, F; Bellazzini, R; Berenji, B; Bhat, P N; Bissaldi, E; Blandford, R D; Bloom, E D; Bogaert, G; Bogart, J R; Bonamente, E; Bonnell, J; Borgland, A W; Bouvier, A; Bregeon, J; Brez, A; Briggs, M S; Brigida, M; Bruel, P; Burnett, T H; Burrows, D; Busetto, G; Caliandro, G A; Cameron, R A; Caraveo, P A; Casandjian, J M; Ceccanti, M; Cecchi, C; Celotti, A; Charles, E; Chekhtman, A; Cheung, C C; Chiang, J; Ciprini, S; Claus, R; Cohen-Tanugi, J; Cominsky, L R; Connaughton, V; Conrad, J; Costamante, L; Cutini, S; Deklotz, M; Dermer, C D; de Angelis, A; de Palma, F; Digel, S W; Dingus, B L; do Couto E Silva, E; Drell, P S; Dubois, R; Dumora, D; Edmonds, Y; Evans, P A; Fabiani, D; Farnier, C; Favuzzi, C; Finke, J; Fishman, G; Focke, W B; Frailis, M; Fukazawa, Y; Funk, S; Fusco, P; Gargano, F; Gasparrini, D; Gehrels, N; Germani, S; Giebels, B; Giglietto, N; Giommi, P; Giordano, F; Glanzman, T; Godfrey, G; Goldstein, A; Granot, J; Greiner, J; Grenier, I A; Grondin, M-H; Grove, J E; Guillemot, L; Guiriec, S; Haller, G; Hanabata, Y; Harding, A K; Hayashida, M; Hays, E; Hernando Morat, J A; Hoover, A; Hughes, R E; Jóhannesson, G; Johnson, A S; Johnson, R P; Johnson, T J; Johnson, W N; Kamae, T; Katagiri, H; Kataoka, J; Kavelaars, A; Kawai, N; Kelly, H; Kennea, J; Kerr, M; Kippen, R M; Knödlseder, J; Kocevski, D; Kocian, M L; Komin, N; Kouveliotou, C; Kuehn, F; Kuss, M; Lande, J; Landriu, D; Larsson, S; Latronico, L; Lavalley, C; Lee, B; Lee, S-H; Lemoine-Goumard, M; Lichti, G G; Longo, F; Loparco, F; Lott, B; Lovellette, M N; Lubrano, P; Madejski, G M; Makeev, A; Marangelli, B; Mazziotta, M N; McBreen, S; McEnery, J E; McGlynn, S; Meegan, C; Mészáros, P; Meurer, C; Michelson, P F; Minuti, M; Mirizzi, N; Mitthumsiri, W; Mizuno, T; Moiseev, A A; Monte, C; Monzani, M E; Moretti, E; Morselli, A; Moskalenko, I V; Murgia, S; Nakamori, T; Nelson, D; Nolan, P L; Norris, J P; Nuss, E; Ohno, M; Ohsugi, T; Okumura, A; Omodei, N; Orlando, E; Ormes, J F; Ozaki, M; Paciesas, W S; Paneque, D; Panetta, J H; Parent, D; Pelassa, V; Pepe, M; Perri, M; Pesce-Rollins, M; Petrosian, V; Pinchera, M; Piron, F; Porter, T A; Preece, R; Rainò, S; Ramirez-Ruiz, E; Rando, R; Rapposelli, E; Razzano, M; Razzaque, S; Rea, N; Reimer, A; Reimer, O; Reposeur, T; Reyes, L C; Ritz, S; Rochester, L S; Rodriguez, A Y; Roth, M; Ryde, F; Sadrozinski, H F-W; Sanchez, D; Sander, A; Saz Parkinson, P M; Scargle, J D; Schalk, T L; Segal, K N; Sgrò, C; Shimokawabe, T; Siskind, E J; Smith, D A; Smith, P D; Spandre, G; Spinelli, P; Stamatikos, M; Starck, J-L; Stecker, F W; Steinle, H; Stephens, T E; Strickman, M S; Suson, D J; Tagliaferri, G; Tajima, H; Takahashi, H; Takahashi, T; Tanaka, T; Tenze, A; Thayer, J B; Thayer, J G; Thompson, D J; Tibaldo, L; Torres, D F; Tosti, G; Tramacere, A; Turri, M; Tuvi, S; Usher, T L; van der Horst, A J; Vigiani, L; Vilchez, N; Vitale, V; von Kienlin, A; Waite, A P; Williams, D A; Wilson-Hodge, C; Winer, B L; Wood, K S; Wu, X F; Yamazaki, R; Ylinen, T; Ziegler, M

    2009-03-27

    Gamma-ray bursts (GRBs) are highly energetic explosions signaling the death of massive stars in distant galaxies. The Gamma-ray Burst Monitor and Large Area Telescope onboard the Fermi Observatory together record GRBs over a broad energy range spanning about 7 decades of gammaray energy. In September 2008, Fermi observed the exceptionally luminous GRB 080916C, with the largest apparent energy release yet measured. The high-energy gamma rays are observed to start later and persist longer than the lower energy photons. A simple spectral form fits the entire GRB spectrum, providing strong constraints on emission models. The known distance of the burst enables placing lower limits on the bulk Lorentz factor of the outflow and on the quantum gravity mass.

  3. Fermi Observations of high-energy gamma-ray emissions from GRB 080916C

    CERN Document Server

    Abdo, A A; Arimoto, M; Asano, K; Atwood, W B; Axelsson, M; Baldini, L; Ballet, J; Band, D L; Barbiellini, Guido; Baring, Matthew G; Bastieri, Denis; Battelino, M; Baughman, B M; Bechtol, K; Bellardi, F; Bellazzini, R; Berenji, B; Bhat, P N; Bissaldi, E; Blandford, R D; Bloom, Elliott D; Bogaert, G; Bogart, J R; Bonamente, E; Bonnell, J; Borgland, A W; Bouvier, A; Bregeon, J; Brez, A; Briggs, M S; Brigida, M; Bruel, P; Burnett, Thompson H; Burrows, David N; Busetto, Giovanni; Caliandro, G A; Cameron, R A; Caraveo, P A; Casandjian, J M; Ceccanti, M; Cecchi, C; Celotti, Annalisa; Charles, E; Chekhtman, A; Cheung, C.C.Teddy; Chiang, J; Ciprini, S; Claus, R; Cohen-Tanugi, Johann; Cominsky, Lynn R; Connaughton, V; Conrad, J; Costamante, L; Cutini, S; DeKlotz, M; Dermer, C D; De Angelis, Alessandro; de Palma, F; Digel, S W; Dingus, B L; do Couto e Silva, Eduardo; Drell, P S; Dubois, R; Dumora, D; Edmonds, Y; Evans, P A; Fabiani, D; Farnier, C; Favuzzi, C; Finke, Justin D; Fishman, G; Focke, W B; Frailis, M; Fukazawa, Y; Funk, S; Fusco, P; Gargano, F; Gasparrini, D; Gehrels, N; Germani, S; Giebels, B; Giglietto, N; Giommi, P; Giordano, F; Glanzman, Thomas Lynn; Godfrey, Gary L; Goldstein, A; Granot, J; Greiner, J; Grenier, I A; Grondin, M H; Grove, J.Eric; Guillemot, L; Guiriec, S; Haller, G; Hanabata, Y; Harding, Alice K; Hayashida, M; Hays, Elizabeth A; Hernando Morata, J A; Hoover, A; Hughes, R E; Johannesson, G; Johnson, A S; Johnson, R P; Johnson, T J; Johnson, W N; Kamae, Tsuneyoshi; Katagiri, H; Kataoka, J; Kavelaars, A; Kawai, N; Kelly, H; Kennea, J; Kerr, M; Kippen, R M; Knodlseder, J; Kocevski, D; Kocian, M L; Komin, N; Kouveliotou, C; Kuehn, Frederick Gabriel Ivar; Kuss, Michael; Lande, J; Landriu, D; Larsson, S; Latronico, L; Lavalley, C; Lee, B; Lee, S H; Lemoine-Goumard, M; Lichti, G G; Longo, F; Loparco, F; Lott, B; Lovellette, M N; Lubrano, Pasquale; Madejski, G M; Makeev, A; Marangelli, B; Mazziotta, M N; McBreen, Sheila; McEnery, J E; McGlynn, S; Meegan, C; Miszaros, P; Meurer, C; Michelson, P F; Minuti, M; Mirizzi, N; Mitthumsiri, W; Mizuno, T; Moiseev, A A; Monte, C; Monzani, M E; Moretti, E; Morselli, A; Moskalenko, Igor Vladimirovich; Murgia, Simona; Nakamori, T; Nelson, D; Nolan, P L; Norris, J P; Nuss, E; Ohno, M; Ohsugi, Takashi; Okumura, Akira; Omodei, N; Orlando, E; Ormes, J F; Ozaki, M; Paciesas, W S; Paneque, D; Panetta, J H; Parent, D; Pelassa, V; Pepe, M; Perri, M; Pesce-Rollins, M; Petrosian, Vahe; Pinchera, M; Piron, F; Porter, Troy A; Preece, R; Rainr, S; Ramirez-Ruiz, E; Rando, R; Rapposelli, E; Razzano, M; Razzaque, Soebur; Rea, N; Reimer, A; Reimer, O; Reposeur, Thierry; Reyes, Luis C; Ritz, S; Rochester, L S; Rodriguez, A Y; Roth, M; Ryde, F; Sadrozinski, H F W; Sanchez, D; Sander, A; Parkinson, P.M.Saz; Scargle, J D; Schalk, T L; Segal, K N; Sgro, C; Shimokawabe, T; Siskind, E J; Smith, D A; Smith, P D; Spandre, G; Spinelli, P; Stamatikos, M; Starck, Jean-Luc; Stecker, Floyd William; Steinle, H; Stephens, T E; Strickman, M S; Suson, Daniel J; Tagliaferri, G.; Tajima, Hiroyasu; Takahashi, H; Takahashi, T; Tanaka, T; Tenze, A; Thayer, J B; Thayer, J G; Thompson, D J; Tibaldo, L; Torres, Diego F; Tosti, G; Tramacere, A; Turri, M; Tuvi, S; Usher, T L; van der Horst, A J; Vigiani, L; Vilchez, N; Vitale, V; von Kienlin, A; Waite, A P; Williams, D A; Wilson-Hodge, C; Winer, B L; Wood, K S; Wu, X F; Yamazaki, R; Ylinen, T; Ziegler, M

    2009-01-01

    Gamma-ray bursts (GRBs) are highly energetic explosions signaling the death of massive stars in distant galaxies. The Gamma-ray Burst Monitor and Large Area Telescope onboard the Fermi Observatory together record GRBs over a broad energy range spanning about 7 decades of gammaray energy. In September 2008, Fermi observed the exceptionally luminous GRB 080916C, with the largest apparent energy release yet measured. The high-energy gamma rays are observed to start later and persist longer than the lower energy photons. A simple spectral form fits the entire GRB spectrum, providing strong constraints on emission models. The known distance of the burst enables placing lower limits on the bulk Lorentz factor of the outflow and on the quantum gravity mass.

  4. Ultra-high energy cosmic rays and prompt TeV gamma rays from ...

    Indian Academy of Sciences (India)

    physics pp. 789-792. Ultra-high energy cosmic rays and prompt. TeV gamma rays from gamma ray bursts ... The origin of the observed ultra-high energy cosmic ray (UHECR) events with ... are proton and electron rest mass, respectively.

  5. Localised Microwave Bursts During ELMs on MAST

    Directory of Open Access Journals (Sweden)

    Freethy Simon

    2015-01-01

    Full Text Available Bursts of microwave emission are observed during ELM events on the Mega Ampère Spherical Tokamak. In agreement with observations on other machines, these bursts are up to 3 orders of magnitude more intense than the thermal background, but are electron cyclotron in nature. The peak in microwave emission is ~20μ before the peak in midplane Dα emission. Using the Synthetic Aperture Microwave Imaging radiometer, we are able to demonstrate that these bursts are often highly spatially localised and preferentially occur at the tokamak midplane. It is hypothesised that the localisation is a result of Doppler resonance broadening for electron Bernstein waves and the high perpendicular electron energies could be the result of pitch angle scattering in high collisionality regions of the plasma.

  6. Production of high energy neutrinos in relativistic supernova shock waves

    International Nuclear Information System (INIS)

    Weaver, T.A.

    1979-01-01

    The possibility of producing high-energy neutrinos (> approx. 10 GeV) in relativistic supernova shock waves is considered. It is shown that, even if the dissipation in such shocks is due to hard hadron--hadron collisions, the resulting flux of neutrinos is too small to be observed by currently envisioned detectors. The associated burst of hard γ-rays, however, may be detectable. 3 tables

  7. The supernova-gamma-ray burst-jet connection.

    Science.gov (United States)

    Hjorth, Jens

    2013-06-13

    The observed association between supernovae and gamma-ray bursts represents a cornerstone in our understanding of the nature of gamma-ray bursts. The collapsar model provides a theoretical framework for this connection. A key element is the launch of a bipolar jet (seen as a gamma-ray burst). The resulting hot cocoon disrupts the star, whereas the (56)Ni produced gives rise to radioactive heating of the ejecta, seen as a supernova. In this discussion paper, I summarize the observational status of the supernova-gamma-ray burst connection in the context of the 'engine' picture of jet-driven supernovae and highlight SN 2012bz/GRB 120422A--with its luminous supernova but intermediate high-energy luminosity--as a possible transition object between low-luminosity and jet gamma-ray bursts. The jet channel for supernova explosions may provide new insights into supernova explosions in general.

  8. Long X-ray burst monitoring with INTEGRAL

    DEFF Research Database (Denmark)

    X-ray bursts are thermonuclear explosions on the surface of accreting neutron stars in low mass X-ray binary systems. In the frame of the INTEGRAL observational Key Programme over the Galactic Center a good number of the known X-ray bursters are frequently being monitored. An international...... collaboration lead by the JEM-X team at the Danish National Space Center has proposed to exploit the improved sensitivity of the INTEGRAL instruments to investigate the observational properties and physics up to high energies of exceptional burst events lasting between a few tens of minutes and several hours....... Of special interest are low luminosity bursting sources that exhibit X-ray bursts of very different durations allowing to study the transition from a hydrogen-rich bursting regime to a pure helium regime and from helium burning to carbon burning. I will present results obtained from INTEGRAL archive data...

  9. Spatial distribution of the gamma-ray bursts at very high redshift

    Science.gov (United States)

    Mészáros, Attila

    2018-05-01

    The author - with his collaborators - already in years 1995-96 have shown - purely from the analyses of the observations - that the gamma-ray bursts (GRBs) can be till redshift 20. Since that time several other statistical studies of the spatial distribution of GRBs were provided. Remarkable conclusions concerning the star-formation rate and the validity of the cosmological principle were obtained about the regions of the cosmic dawn. In this contribution these efforts are surveyed.

  10. Theoretical high energy physics

    International Nuclear Information System (INIS)

    Lee, T.D.

    1993-01-01

    Brief reports are given on the work of several professors. The following areas are included: quantum chromodynamics calculations using numerical lattice gauge theory and a high-speed parallel computer; the ''spin wave'' description of bosonic particles moving on a lattice with same-site exclusion; a high-temperature expansion to 13th order for the O(4)-symmetric φ 4 model on a four-dimensional F 4 lattice; spin waves and lattice bosons; superconductivity of C 60 ; meson-meson interferometry in heavy-ion collisions; baryon number violation in the Standard Model in high-energy collisions; hard thermal loops in QCD; electromagnetic interactions of anyons; the relation between Bose-Einstein and BCS condensations; Euclidean wormholes with topology S 1 x S 2 x R; vacuum decay and symmetry breaking by radiative corrections; inflationary solutions to the cosmological horizon and flatness problems; and magnetically charged black holes

  11. High frequency energy measurements

    International Nuclear Information System (INIS)

    Stotlar, S.C.

    1981-01-01

    High-frequency (> 100 MHz) energy measurements present special problems to the experimenter. Environment or available electronics often limit the applicability of a given detector type. The physical properties of many detectors are frequency dependent and in some cases, the physical effect employed can be frequency dependent. State-of-the-art measurements generally involve a detection scheme in association with high-speed electronics and a method of data recording. Events can be single or repetitive shot requiring real time, sampling, or digitizing data recording. Potential modification of the pulse by the detector and the associated electronics should not be overlooked. This presentation will review typical applications, methods of choosing a detector, and high-speed detectors. Special considerations and limitations of some applications and devices will be described

  12. High energy photon emission from wakefields

    Energy Technology Data Exchange (ETDEWEB)

    Farinella, D. M., E-mail: dfarinel@uci.edu; Lau, C. K.; Taimourzadeh, S.; Hwang, Y.; Abazajian, K.; Canac, N.; Taborek, P.; Tajima, T. [Department of Physics and Astronomy, University of California, Irvine, California 92697 (United States); Zhang, X. M., E-mail: zhxm@siom.ac.cn [Department of Physics and Astronomy, University of California, Irvine, California 92697 (United States); Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Koga, J. K., E-mail: koga.james@qst.go.jp [Kansai Photon Science Institute, Japan Atomic Energy Agency (JAEA), Kizugawa, Kyoto 619-0215 (Japan); Ebisuzaki, T., E-mail: ebisu@riken.jp [RIKEN, Wako, Saitama 351-0198 (Japan)

    2016-07-15

    Experimental evidence has accumulated to indicate that wakefield acceleration (WFA) accompanies intense and sometimes coherent emission of radiation such as from betatron radiation. The investigation of this issue has additional impetus nowadays because we are learning (1) there is an additional acceleration process of the ponderomotive acceleration; (2) WFA may become relevant in much higher density regimes; (3) WFA has been proposed as the mechanism for extreme high energy cosmic ray acceleration and gamma ray bursts for active galactic nuclei. These require us to closely examine the radiative mechanisms in WFA anew. We report studies of radiation from wakefield (self-injected betatron) and ponderomotive (laser field) mechanisms in scalings of the frequency and intensity of the driver, as well as the plasma density.

  13. High energy ion implantation

    International Nuclear Information System (INIS)

    Ziegler, J.F.

    1985-01-01

    High energy ion implantation offers the oppertunity for unique structures in semiconductor processing. The unusual physical properties of such implantations are discussed as well as the special problems in masking and damage annealing. A review is made of proposed circuit structures which involve deep implantation. Examples are: deep buried bipolar collectors fabricated without epitaxy, barrier layers to reduce FET memory sensitivity to soft-fails, CMOS isolation well structures, MeV implantation for customization and correction of completed circuits, and graded reach-throughs to deep active device components. (orig.)

  14. High energy physics

    International Nuclear Information System (INIS)

    Fortney, L.R.; Goshaw, A.T.; Walker, W.D.

    1991-01-01

    This progress report presents a review of research done over the past five years by the Duke High Energy Physics Group. This research has been centered at Fermilab where we have had a continuing involvement with both the Tevatron collider and fixed-target programs. In 1988 we began extensive detector R ampersand D for the SSC through its Major Subsystem Program. Duke has been an active member of the Solenoidal Detector Collaboration (SDC) since its formation. These last five years has also been used to finish the analysis of data from a series of hybrid bubble chamber experiments which formed the core of Duke's research program in the early 1980's

  15. High energy cosmic rays

    CERN Document Server

    Stanev, Todor

    2010-01-01

    Offers an accessible text and reference (a cosmic-ray manual) for graduate students entering the field and high-energy astrophysicists will find this an accessible cosmic-ray manual Easy to read for the general astronomer, the first part describes the standard model of cosmic rays based on our understanding of modern particle physics. Presents the acceleration scenario in some detail in supernovae explosions as well as in the passage of cosmic rays through the Galaxy. Compares experimental data in the atmosphere as well as underground are compared with theoretical models

  16. Prospects at high energies

    International Nuclear Information System (INIS)

    Quigg, C.

    1988-11-01

    I discuss some possibilities for neutrino experiments in the fixed-target environment of the SPS, Tevatron, and UNK, with their primary proton beams of 0.4, 0.9, and 3.0 TeV. The emphasis is on unfinished business: issues that have been recognized for some time, but not yet resolved. Then I turn to prospects for proton-proton colliders to explore the 1-TeV scale. I review the motivation for new physics in the neighborhood of 1 TeV and mention some discovery possibilities for high-energy, high-luminosity hadron colliders and the implications they would have for neutrino physics. I raise the possibility of the direct study of neutrino interactions in hadron colliders. I close with a report on the status of the SSC project. 38 refs., 17 figs

  17. High energy high repetition-rate thin-disk amplifier for OPCPA pumping

    Energy Technology Data Exchange (ETDEWEB)

    Schulz, Michael

    2013-08-15

    The development of a pump laser system for a high power and high repetition rate optical parametric chirped-pulse amplification (OPCPA) is presented in this thesis. The OPCPA system requires pump pulse energies in the range of tens of millijoules at high repetition rates with sub-picosecond pulse durations. This can be achieved to some extend with Innoslab amplifier technology. However, scaling to higher pulse energies at high repetition rates may be problematic. With the thin-disk amplifier presented in this thesis, output energies of 140 mJ at 100 kHz repetition rate could be achieved in burst-mode operation, which is a world record for this type of laser amplifier. Due to its material and spectral properties, ytterbium doped YAG (Yb:YAG) is used as a gain medium for the high power amplifier stages. The low quantum defect and the comparatively large emission bandwidth makes this material the choice for high power operation and sub-picosecond compressed pulse durations. The output beam profile as well as the shape of the output bursts is ideal to pump an OPCPA system. An OPCPA output energy in the millijoule range with repetition rates of 100 kHz to 1 MHz is needed to generate seed pulses for the FEL and for the application as pump-probe laser at the FEL facility. Since the development of this laser system needs to meet requirements set by the Free-Electron Laser in Hamburg (FLASH), the amplifier is conceived for burst-mode operation. The main requirement is a high intra-burst pulse repetition rate of more than 100 kHz and a uniform pulse train (burst) with equal properties for every pulse. The burst-mode is an operation mode where the laser never reaches a lasing equilibrium, which means that the behavior of the amplifier is similar to a switch-on of the laser system for every burst. This makes the development of the amplifier system difficult. Therefore, an analytical model has been developed to study the amplification process during the burst. This includes the

  18. High energy high repetition-rate thin-disk amplifier for OPCPA pumping

    International Nuclear Information System (INIS)

    Schulz, Michael

    2013-08-01

    The development of a pump laser system for a high power and high repetition rate optical parametric chirped-pulse amplification (OPCPA) is presented in this thesis. The OPCPA system requires pump pulse energies in the range of tens of millijoules at high repetition rates with sub-picosecond pulse durations. This can be achieved to some extend with Innoslab amplifier technology. However, scaling to higher pulse energies at high repetition rates may be problematic. With the thin-disk amplifier presented in this thesis, output energies of 140 mJ at 100 kHz repetition rate could be achieved in burst-mode operation, which is a world record for this type of laser amplifier. Due to its material and spectral properties, ytterbium doped YAG (Yb:YAG) is used as a gain medium for the high power amplifier stages. The low quantum defect and the comparatively large emission bandwidth makes this material the choice for high power operation and sub-picosecond compressed pulse durations. The output beam profile as well as the shape of the output bursts is ideal to pump an OPCPA system. An OPCPA output energy in the millijoule range with repetition rates of 100 kHz to 1 MHz is needed to generate seed pulses for the FEL and for the application as pump-probe laser at the FEL facility. Since the development of this laser system needs to meet requirements set by the Free-Electron Laser in Hamburg (FLASH), the amplifier is conceived for burst-mode operation. The main requirement is a high intra-burst pulse repetition rate of more than 100 kHz and a uniform pulse train (burst) with equal properties for every pulse. The burst-mode is an operation mode where the laser never reaches a lasing equilibrium, which means that the behavior of the amplifier is similar to a switch-on of the laser system for every burst. This makes the development of the amplifier system difficult. Therefore, an analytical model has been developed to study the amplification process during the burst. This includes the

  19. High energy physics

    International Nuclear Information System (INIS)

    Kernan, A.; Shen, B.C.; Ma, E.

    1997-01-01

    This proposal is for the continuation of the High Energy Physics program at the University of California at Riverside. In hadron collider physics the authors will complete their transition from experiment UA1 at CERN to the DZERO experiment at Fermilab. On experiment UA1 their effort will concentrate on data analysis at Riverside. At Fermilab they will coordinate the high voltage system for all detector elements. They will also carry out hardware/software development for the D0 muon detector. The TPC/Two-Gamma experiment has completed its present phase of data-taking after accumulating 160 pb - 1 of luminosity. The UC Riverside group will continue data and physics analysis and make minor hardware improvement for the high luminosity run. The UC Riverside group is participating in design and implementation of the data acquisition system for the OPAL experiment at LEP. Mechanical and electronics construction of the OPAL hadron calorimeter strip readout system is proceeding on schedule. Data analysis and Monte Carlo detector simulation efforts are proceeding in preparation for the first physics run when IEP operation comenses in fall 1989

  20. High energy astrophysical techniques

    CERN Document Server

    Poggiani, Rosa

    2017-01-01

    This textbook presents ultraviolet and X-ray astronomy, gamma-ray astronomy, cosmic ray astronomy, neutrino astronomy, and gravitational wave astronomy as distinct research areas, focusing on the astrophysics targets and the requirements with respect to instrumentation and observation methods. The purpose of the book is to bridge the gap between the reference books and the specialized literature. For each type of astronomy, the discussion proceeds from the orders of magnitude for observable quantities. The physical principles of photon and particle detectors are then addressed, and the specific telescopes and combinations of detectors, presented. Finally the instruments and their limits are discussed with a view to assisting readers in the planning and execution of observations. Astronomical observations with high-energy photons and particles represent the newest additions to multimessenger astronomy and this book will be of value to all with an interest in the field.

  1. A highly efficient SDRAM controller supporting variable-length burst access and batch process for discrete reads

    Science.gov (United States)

    Li, Nan; Wang, Junzheng

    2016-03-01

    A highly efficient Synchronous Dynamic Random Access Memory (SDRAM) controller supporting variable-length burst access and batch process for discrete reads is proposed in this paper. Based on the Principle of Locality, command First In First Out (FIFO) and address range detector are designed within this controller to accelerate its responses to discrete read requests, which dramatically improves the average Effective Bus Utilization Ratio (EBUR) of SDRAM. Our controller is finally verified by driving the Micron 256-Mb SDRAM MT48LC16M16A2. Successful simulation and verification results show that our controller exhibits much higher EBUR than do most existing designs in case of discrete reads.

  2. Heterogeneity in Short Gamma-Ray Bursts

    Science.gov (United States)

    Norris, Jay P.; Gehrels Neil; Scargle, Jeffrey D.

    2011-01-01

    We analyze the Swift/BAT sample of short gamma-ray bursts, using an objective Bayesian Block procedure to extract temporal descriptors of the bursts' initial pulse complexes (IPCs). The sample comprises 12 and 41 bursts with and without extended emission (EE) components, respectively. IPCs of non-EE bursts are dominated by single pulse structures, while EE bursts tend to have two or more pulse structures. The medians of characteristic timescales - durations, pulse structure widths, and peak intervals - for EE bursts are factors of approx 2-3 longer than for non-EE bursts. A trend previously reported by Hakkila and colleagues unifying long and short bursts - the anti-correlation of pulse intensity and width - continues in the two short burst groups, with non-EE bursts extending to more intense, narrower pulses. In addition we find that preceding and succeeding pulse intensities are anti-correlated with pulse interval. We also examine the short burst X-ray afterglows as observed by the Swift/XRT. The median flux of the initial XRT detections for EE bursts (approx 6 X 10(exp -10) erg / sq cm/ s) is approx > 20 x brighter than for non-EE bursts, and the median X-ray afterglow duration for EE bursts (approx 60,000 s) is approx 30 x longer than for non-EE bursts. The tendency for EE bursts toward longer prompt-emission timescales and higher initial X-ray afterglow fluxes implies larger energy injections powering the afterglows. The longer-lasting X-ray afterglows of EE bursts may suggest that a significant fraction explode into more dense environments than non-EE bursts, or that the sometimes-dominant EE component efficiently p()wers the afterglow. Combined, these results favor different progenitors for EE and non-EE short bursts.

  3. HETEROGENEITY IN SHORT GAMMA-RAY BURSTS

    International Nuclear Information System (INIS)

    Norris, Jay P.; Gehrels, Neil; Scargle, Jeffrey D.

    2011-01-01

    We analyze the Swift/BAT sample of short gamma-ray bursts, using an objective Bayesian Block procedure to extract temporal descriptors of the bursts' initial pulse complexes (IPCs). The sample is comprised of 12 and 41 bursts with and without extended emission (EE) components, respectively. IPCs of non-EE bursts are dominated by single pulse structures, while EE bursts tend to have two or more pulse structures. The medians of characteristic timescales-durations, pulse structure widths, and peak intervals-for EE bursts are factors of ∼2-3 longer than for non-EE bursts. A trend previously reported by Hakkila and colleagues unifying long and short bursts-the anti-correlation of pulse intensity and width-continues in the two short burst groups, with non-EE bursts extending to more intense, narrower pulses. In addition, we find that preceding and succeeding pulse intensities are anti-correlated with pulse interval. We also examine the short burst X-ray afterglows as observed by the Swift/X-Ray Telescope (XRT). The median flux of the initial XRT detections for EE bursts (∼6x10 -10 erg cm -2 s -1 ) is ∼>20x brighter than for non-EE bursts, and the median X-ray afterglow duration for EE bursts (∼60,000 s) is ∼30x longer than for non-EE bursts. The tendency for EE bursts toward longer prompt-emission timescales and higher initial X-ray afterglow fluxes implies larger energy injections powering the afterglows. The longer-lasting X-ray afterglows of EE bursts may suggest that a significant fraction explode into denser environments than non-EE bursts, or that the sometimes-dominant EE component efficiently powers the afterglow. Combined, these results favor different progenitors for EE and non-EE short bursts.

  4. High frequency ion sound waves associated with Langmuir waves in type III radio burst source regions

    Directory of Open Access Journals (Sweden)

    G. Thejappa

    2004-01-01

    Full Text Available Short wavelength ion sound waves (2-4kHz are detected in association with the Langmuir waves (~15-30kHz in the source regions of several local type III radio bursts. They are most probably not due to any resonant wave-wave interactions such as the electrostatic decay instability because their wavelengths are much shorter than those of Langmuir waves. The Langmuir waves occur as coherent field structures with peak intensities exceeding the Langmuir collapse thresholds. Their scale sizes are of the order of the wavelength of an ion sound wave. These Langmuir wave field characteristics indicate that the observed short wavelength ion sound waves are most probably generated during the thermalization of the burnt-out cavitons left behind by the Langmuir collapse. Moreover, the peak intensities of the observed short wavelength ion sound waves are comparable to the expected intensities of those ion sound waves radiated by the burnt-out cavitons. However, the speeds of the electron beams derived from the frequency drift of type III radio bursts are too slow to satisfy the needed adiabatic ion approximation. Therefore, some non-linear process such as the induced scattering on thermal ions most probably pumps the beam excited Langmuir waves towards the lower wavenumbers, where the adiabatic ion approximation is justified.

  5. The series elastic shock absorber: tendon elasticity modulates energy dissipation by muscle during burst deceleration.

    Science.gov (United States)

    Konow, Nicolai; Roberts, Thomas J

    2015-04-07

    During downhill running, manoeuvring, negotiation of obstacles and landings from a jump, mechanical energy is dissipated via active lengthening of limb muscles. Tendon compliance provides a 'shock-absorber' mechanism that rapidly absorbs mechanical energy and releases it more slowly as the recoil of the tendon does work to stretch muscle fascicles. By lowering the rate of muscular energy dissipation, tendon compliance likely reduces the risk of muscle injury that can result from rapid and forceful muscle lengthening. Here, we examine how muscle-tendon mechanics are modulated in response to changes in demand for energy dissipation. We measured lateral gastrocnemius (LG) muscle activity, force and fascicle length, as well as leg joint kinematics and ground-reaction force, as turkeys performed drop-landings from three heights (0.5-1.5 m centre-of-mass elevation). Negative work by the LG muscle-tendon unit during landing increased with drop height, mainly owing to greater muscle recruitment and force as drop height increased. Although muscle strain did not increase with landing height, ankle flexion increased owing to increased tendon strain at higher muscle forces. Measurements of the length-tension relationship of the muscle indicated that the muscle reached peak force at shorter and likely safer operating lengths as drop height increased. Our results indicate that tendon compliance is important to the modulation of energy dissipation by active muscle with changes in demand and may provide a mechanism for rapid adjustment of function during deceleration tasks of unpredictable intensity. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  6. High energy magnetic excitations

    International Nuclear Information System (INIS)

    Endoh, Yasuo

    1988-01-01

    The report emphasizes that the current development in condensed matter physics opens a research field fit to inelastic neutron scattering experiments in the eV range which is easilly accessed by spallation neutron sources. Several important subjects adopted at thermal reactors are shown. It is desired to extend the implementation of the spectroscopic experiments for investigation of higher energy magnetic excitations. For La 2 CuO 4 , which is the mother crystal of the first high Tc materials found by Bednortz and Muller, it seems to be believed that the magnetism is well characterized by the two-dimensional Heisenberg antiferromagnetic Hamiltonian, and it is widely accepted that the magnetism is a most probable progenitor of high Tc superconductors. The unusual properties of spin correlations in this crystal have been studied extensively by standard neutron scattering techniques with steady neutrons at BNL. FeSi is not ordered magnetically but shows a very unique feature of temperature induced magnetism, which also has been studied extensively by using the thermal neutron scattering technique at BNL. In these experiments, polarized neutrons are indispensable to extract the clean magnetic components out of other components of non-magnetic scattering. (N.K.)

  7. Advances in gamma-ray burst astronomy

    International Nuclear Information System (INIS)

    Cline, T.L.; Desai, U.D.

    1976-01-01

    Work at Goddard is presently being carried out in three major areas of gamma-ray burst research: (1) A pair of simultaneously operating 0.8-m 2 burst detectors were successfully balloon-borne at locations 800 miles apart on 9 May, 1975, each to atmospheric depths of 3 to 4 g cm -2 , for a 20-h period of coincident data coverage. This experiment investigates the size spectrum of bursts in the 10 -7 to 10 -6 erg cm -2 size region where dozens of events per day are expected on a -1.5 index integral power-law extrapolation. Considerable separation in latitude was used to avoid possible atmospheric and auroral secondary effects. Its results are not yet available. (2) A deep-space burst detector, the first spacecraft instrument built specifically for gamma-ray burst studies, was recently successfully integrated into the Helios-B space probe. Its use at distances of up to 2 AU will make possible the first high-resolution directional study of gamma-ray burst source locations. Similar modifications to several other space vehicles are also being prepared. (3) The gamma-ray instrument on the IMP-7 satellite is presently the most sensitive burst detector still operating in orbit. Its results have shown that all measured event-average energy spectra are consistent with being alike. Using this characteristic spectrum to select IMP-7 candidate events of smaller size than those detected using other spacecraft in coincidence, a size spectrum is constructed which fits the -1.5 index power law down to 2.5 x 10 -5 erg cm -2 per event, at an occurrence rate of about once per month. (Auth.)

  8. Burst Speed of Wild Fishes under High-Velocity Flow Conditions Using Stamina Tunnel with Natural Guidance System in River

    Science.gov (United States)

    Izumi, Mattashi; Yamamoto, Yasuyuki; Yataya, Kenichi; Kamiyama, Kohhei

    Swimming experiments were conducted on wild fishes in a natural guidance system stamina tunnel (cylindrical pipe) installed in a fishway of a local river under high-velocity flow conditions (tunnel flow velocity : 211 to 279 cm·s-1). In this study, the swimming characteristics of fishes were observed. The results show that (1) the swimming speeds of Tribolodon hakonensis (Japanese dace), Phoxinus lagowshi steindachneri (Japanese fat-minnow), Plecoglossus altivelis (Ayu), and Zacco platypus (Pale chub) were in proportion to their body length under identical water flow velocity conditions; (2) the maximum burst speed of Japanese dace and Japanese fat-minnow (measuring 4 to 6 cm in length) was 262 to 319 cm·s-1 under high flow velocity conditions (225 to 230 cm·s-1), while the maximum burst speed of Ayu and Pale chub (measuring 5 cm to 12 cm in length) was 308 to 355 cm·s-1 under high flow velocity conditions (264 to 273 cm·s-1) ; (3) the 50cm-maximum swimming speed of swimming fishes was 1.07 times faster than the pipe-swimming speed; (4) the faster the flow velocity, the shorter the swimming distance became.

  9. Computing in high energy physics

    Energy Technology Data Exchange (ETDEWEB)

    Watase, Yoshiyuki

    1991-09-15

    The increasingly important role played by computing and computers in high energy physics is displayed in the 'Computing in High Energy Physics' series of conferences, bringing together experts in different aspects of computing - physicists, computer scientists, and vendors.

  10. FSU High Energy Physics

    Energy Technology Data Exchange (ETDEWEB)

    Prosper, Harrison B. [Florida State Univ., Tallahassee, FL (United States); Adams, Todd [Florida State Univ., Tallahassee, FL (United States); Askew, Andrew [Florida State Univ., Tallahassee, FL (United States); Berg, Bernd [Florida State Univ., Tallahassee, FL (United States); Blessing, Susan K. [Florida State Univ., Tallahassee, FL (United States); Okui, Takemichi [Florida State Univ., Tallahassee, FL (United States); Owens, Joseph F. [Florida State Univ., Tallahassee, FL (United States); Reina, Laura [Florida State Univ., Tallahassee, FL (United States); Wahl, Horst D. [Florida State Univ., Tallahassee, FL (United States)

    2014-12-01

    The High Energy Physics group at Florida State University (FSU), which was established in 1958, is engaged in the study of the fundamental constituents of matter and the laws by which they interact. The group comprises theoretical and experimental physicists, who sometimes collaborate on projects of mutual interest. The report highlights the main recent achievements of the group. Significant, recent, achievements of the group’s theoretical physicists include progress in making precise predictions in the theory of the Higgs boson and its associated processes, and in the theoretical understanding of mathematical quantities called parton distribution functions that are related to the structure of composite particles such as the proton. These functions are needed to compare data from particle collisions, such as the proton-proton collisions at the CERN Large Hadron Collider (LHC), with theoretical predictions. The report also describes the progress in providing analogous functions for heavy nuclei, which find application in neutrino physics. The report highlights progress in understanding quantum field theory on a lattice of points in space and time (an area of study called lattice field theory), the progress in constructing several theories of potential new physics that can be tested at the LHC, and interesting new ideas in the theory of the inflationary expansion of the very early universe. The focus of the experimental physicists is the Compact Muon Solenoid (CMS) experiment at CERN. The report, however, also includes results from the D0 experiment at Fermilab to which the group made numerous contributions over a period of many years. The experimental group is particularly interested in looking for new physics at the LHC that may provide the necessary insight to extend the standard model (SM) of particle physics. Indeed, the search for new physics is the primary task of contemporary particle physics, one motivated by the need to explain certain facts, such as the

  11. High energy physics

    International Nuclear Information System (INIS)

    Kernan, A.; Shen, B.C.; Ma, E.

    1997-01-01

    This proposal is for the continuation of the High Energy Physics Program at the University of California, Riverside. In 1990, we will concentrate on analysis of LEP data from the OPAL detector. We expect to record 10 5 Z's by the end of 1989 and 10 6 in 1990. This data will be used to measure the number of quark-lepton families in the universe. In the second half of 1990 we will also be occupied with the installation of the D-Zero detector in the Tevatron Collider and the preparation of software for the 1991 run. A new initiative made possible by generous university support is a laboratory for detector development at UCR. The focus will be on silicon strip tracking detectors both for the D-Zero upgrade and for SSC physics. The theory program will pursue further various mass-generating radiative mechanisms for understanding small quark and lepton masses as well as some novel phenomenological aspects of supersymmetry

  12. High energy plasma accelerators

    International Nuclear Information System (INIS)

    Tajima, T.

    1985-05-01

    Colinear intense laser beams ω 0 , kappa 0 and ω 1 , kappa 1 shone on a plasma with frequency separation equal to the electron plasma frequency ω/sub pe/ are capable of creating a coherent large longitudinal electric field E/sub L/ = mc ω/sub pe//e of the order of 1GeV/cm for a plasma density of 10 18 cm -3 through the laser beat excitation of plasma oscillations. Accompanying favorable and deleterious physical effects using this process for a high energy beat-wave accelerator are discussed: the longitudinal dephasing, pump depletion, the transverse laser diffraction, plasma turbulence effects, self-steepening, self-focusing, etc. The basic equation, the driven nonlinear Schroedinger equation, is derived to describe this system. Advanced accelerator concepts to overcome some of these problems are proposed, including the plasma fiber accelerator of various variations. An advanced laser architecture suitable for the beat-wave accelerator is suggested. Accelerator physics issues such as the luminosity are discussed. Applications of the present process to the current drive in a plasma and to the excitation of collective oscillations within nuclei are also discussed

  13. Low-luminosity gamma-ray bursts as the sources of ultrahigh-energy cosmic ray nuclei

    Science.gov (United States)

    Zhang, B. Theodore; Murase, Kohta; Kimura, Shigeo S.; Horiuchi, Shunsaku; Mészáros, Peter

    2018-04-01

    Recent results from the Pierre Auger Collaboration have shown that the composition of ultrahigh-energy cosmic rays (UHECRs) becomes gradually heavier with increasing energy. Although gamma-ray bursts (GRBs) have been promising sources of UHECRs, it is still unclear whether they can account for the Auger results because of their unknown nuclear composition of ejected UHECRs. In this work, we revisit the possibility that low-luminosity GRBs (LL GRBs) act as the sources of UHECR nuclei and give new predictions based on the intrajet nuclear composition models considering progenitor dependencies. We find that the nuclear component in the jet can be divided into two groups according to the mass fraction of silicon nuclei, Si-free and Si-rich. Motivated by the connection between LL GRBs and transrelativistic supernovae, we also consider the hypernova ejecta composition. Then, we discuss the survivability of UHECR nuclei in the jet base and internal shocks of the jets, and show that it is easier for nuclei to survive for typical LL GRBs. Finally, we numerically propagate UHECR nuclei ejected from LL GRBs with different composition models and compare the resulting spectra and composition to Auger data. Our results show that both the Si-rich progenitor and hypernova ejecta models match the Auger data well, while the Si-free progenitor models have more difficulty in fitting the spectrum. We argue that our model is consistent with the newly reported cross-correlation between the UHECRs and starburst galaxies, since both LL GRBs and hypernovae are expected to be tracers of the star-formation activity. LL GRBs have also been suggested as the dominant origin of IceCube neutrinos in the PeV range, and the LL GRB origin of UHECRs can be critically tested by near-future multimessenger observations.

  14. The High Energy Transient Explorer (HETE): Mission and science overview

    International Nuclear Information System (INIS)

    Ricker, G.R.; Crew, G.B.; Doty, J.P.; Vanderspek, R.; Villasenor, J.; Atteia, J.-L.; Fenimore, E.E.; Galassi, M.; Graziani, C.; Lamb, D.Q.; Hurley, K.; Jernigan, J.G.; Kawai, N.; Matsuoka, M.; Pizzichini, G.; Shirasaki, Y.; Tamagawa, T.; Vedrenne, G.; Woosley, S.E.; Yoshida, A.

    2003-01-01

    The High Energy Transient Explorer (HETE ) mission is devoted to the study of gamma-ray bursts (GRBs) using soft X-ray, medium X-ray, and gamma-ray instruments mounted on a compact spacecraft. The HETE satellite was launched into equatorial orbit on 9 October 2000. A science team from France, Japan, Brazil, India, Italy, and the US is responsible for the HETE mission, which was completed for ∼ 1/3 the cost of a NASA Small Explorer (SMEX). The HETE mission is unique in that it is entirely 'self-contained', insofar as it relies upon dedicated tracking, data acquisition, mission operations, and data analysis facilities run by members of its international Science Team. A powerful feature of HETE is its potential for localizing GRBs within seconds of the trigger with good precision (∼ 10') using medium energy X-rays and, for a subset of bright GRBs, improving the localization to ∼ 30''accuracy using low energy X-rays. Real-time GRB localizations are transmitted to ground observers within seconds via a dedicated network of 14 automated 'Burst Alert Stations', thereby allowing prompt optical, IR, and radio follow-up, leading to the identification of counterparts for a large fraction of HETE -localized GRBs. HETE is the only satellite that can provide near-real time localizations of GRBs, and that can localize GRBs that do not have X-ray, optical, and radio afterglows, during the next two years. These capabilities are the key to allowing HETE to probe further the unique physics that produces the brightest known photon sources in the universe. To date (December 2002), HETE has produced 31 GRB localizations. Localization accuracies are routinely in the 4'- 20' range; for the five GRBs with SXC localization, accuracies are ∼1-2'. In addition, HETE has detected ∼ 25 bursts from soft gamma repeaters (SGRs), and >600 X-ray bursts (XRBs)

  15. Coherent combining pulse bursts in time domain

    Science.gov (United States)

    Galvanauskas, Almantas

    2018-01-09

    A beam combining and pulse stacking technique is provided that enhances laser pulse energy by coherent stacking pulse bursts (i.e. non-periodic pulsed signals) in time domain. This energy enhancement is achieved by using various configurations of Fabry-Perot, Gires-Tournois and other types of resonant cavities, so that a multiple-pulse burst incident at either a single input or multiple inputs of the system produces an output with a solitary pulse, which contains the summed energy of the incident multiple pulses from all beams. This disclosure provides a substantial improvement over conventional coherent-combining methods in that it achieves very high pulse energies using a relatively small number of combined laser systems, thus providing with orders of magnitude reduction in system size, complexity, and cost compared to current combining approaches.

  16. High energy neutron generator

    International Nuclear Information System (INIS)

    Barjon, R.; Breynat, G.

    1987-01-01

    This patent describes a generator of fast neutrons only slightly contaminated by neutrons of energy less than 15 MeV, comprising a source of charged particles of energy equal to at least 15 MeV, a target made of lithium deuteride, and means for cooling the target. The target comprises at least two elements placed in series in the path of the charged particles and separated from each other, the thickness of each of the elements being selected as a function of the average energy of the charged particles emitted from the source and the energy of the fast neutrons to be generated such that neutrons of energy equal to at least 15 MeV are emitted in the forward direction in response to the bombardment of the target from behind by the charged particles. The target cooling means comprises means for circulating between and around the elements a gas which does not chemically react with lithium deuteride

  17. Quantum-Gravity Based Photon Dispersion in Gamma-Ray Bursts: The Detection Problem

    International Nuclear Information System (INIS)

    Norris, Jay P.; Scargle, Jeffrey D.

    2007-01-01

    Gamma-ray bursts at cosmological distances offer a time-varying signal that can be used to search for energy-dependent photon dispersion effects. We show that short bursts with narrow pulse structures at high energies will offer the least ambiguous tests for energy-dependent dispersion effects. We discuss quantitative methods to search for such effects in time-tagged photon data. Utilizing observed gamma-ray burst profiles extrapolated to GeV energies, as may expected to be observed by GLAST, we also demonstrate the extent to which these methods can be used as an empirical exploration of quantum gravity formalisms

  18. Dosimetry of high energy radiation

    CERN Document Server

    Sahare, P D

    2018-01-01

    High energy radiation is hazardous to living beings and a threat to mankind. The correct estimation of the high energy radiation is a must and a single technique may not be very successful. The process of estimating the dose (the absorbed energy that could cause damages) is called dosimetry. This book covers the basic technical knowledge in the field of radiation dosimetry. It also makes readers aware of the dangers and hazards of high energy radiation.

  19. US Army Nuclear Burst Detection System (NBDS)

    International Nuclear Information System (INIS)

    Glaser, R.F.

    1980-07-01

    The Nuclear Burst Detection System (NBDS) was developed to meet the Army requirements of an unattended, automatic nuclear burst reporting system. It provides pertinent data for battlefield commanders on a timely basis with high reliability

  20. Renewable Energy Riding High

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    China is putting greater emphasis on green energy as it tries to clean up industry and meet target for cuts in carbon emissions over the past two years, China has already leapfrogged competitors from Denmark, Germany, Spain and the United States to become the world's largest maker of wind turbines and solar panels. At the same time, the country is also taking steps to build more nuclear reactors and energy-efficient coal power plants.

  1. Fast Radio Burst/Gamma-Ray Burst Cosmography

    Science.gov (United States)

    Gao, He; Li, Zhuo; Zhang, Bing

    2014-06-01

    Recently, both theoretical arguments and observational evidence suggested that a small fraction of fast radio bursts (FRBs) could be associated with gamma-ray bursts (GRBs). If such FRB/GRB association systems are commonly detected in the future, the combination of dispersion measures (DM) derived from FRBs and redshifts derived from GRBs makes these systems a plausible tool to conduct cosmography. We quantify uncertainties in deriving the redshift-dependent DM_{IGM} as a function of z and test how well dark energy models can be constrained with Monte Carlo simulations. We show that with several tens of FRB/GRB systems potentially detected in a decade or so, one may reach reasonable constraints on wCDM models. When combined with Type Ia supernova (SN Ia) data, unprecedented constraints on the dark energy equation of state may be achieved, thanks to the prospects of detecting FRB/GRB systems at relatively high redshifts. The ratio between the mean value \\lt {DM_IGM} (z)\\gt and luminosity distance (D L(z)) is insensitive to dark energy models. This gives the prospect of applying SN Ia data to calibrate \\lt {DM_IGM} (z)\\gt using a relatively small sample of FRB/GRB systems, allowing a reliable constraint on the baryon inhomogeneity distribution as a function of redshift. The methodology developed in this paper can also be applied if the FRB redshifts can be measured by other means. Some caveats of putting this method into practice are also discussed.

  2. Fast radio burst/gamma-ray burst cosmography

    International Nuclear Information System (INIS)

    Gao, He; Zhang, Bing; Li, Zhuo

    2014-01-01

    Recently, both theoretical arguments and observational evidence suggested that a small fraction of fast radio bursts (FRBs) could be associated with gamma-ray bursts (GRBs). If such FRB/GRB association systems are commonly detected in the future, the combination of dispersion measures (DM) derived from FRBs and redshifts derived from GRBs makes these systems a plausible tool to conduct cosmography. We quantify uncertainties in deriving the redshift-dependent DM IGM as a function of z and test how well dark energy models can be constrained with Monte Carlo simulations. We show that with several tens of FRB/GRB systems potentially detected in a decade or so, one may reach reasonable constraints on wCDM models. When combined with Type Ia supernova (SN Ia) data, unprecedented constraints on the dark energy equation of state may be achieved, thanks to the prospects of detecting FRB/GRB systems at relatively high redshifts. The ratio between the mean value and luminosity distance (D L (z)) is insensitive to dark energy models. This gives the prospect of applying SN Ia data to calibrate using a relatively small sample of FRB/GRB systems, allowing a reliable constraint on the baryon inhomogeneity distribution as a function of redshift. The methodology developed in this paper can also be applied if the FRB redshifts can be measured by other means. Some caveats of putting this method into practice are also discussed.

  3. Fast radio burst/gamma-ray burst cosmography

    Energy Technology Data Exchange (ETDEWEB)

    Gao, He; Zhang, Bing [Department of Physics and Astronomy, University of Nevada Las Vegas, NV 89154 (United States); Li, Zhuo, E-mail: gaohe@physics.unlv.edu, E-mail: zhang@physics.unlv.edu, E-mail: zhuo.li@pku.edu.cn [Department of Astronomy, School of Physics, Peking University, Beijing 100871 (China)

    2014-06-20

    Recently, both theoretical arguments and observational evidence suggested that a small fraction of fast radio bursts (FRBs) could be associated with gamma-ray bursts (GRBs). If such FRB/GRB association systems are commonly detected in the future, the combination of dispersion measures (DM) derived from FRBs and redshifts derived from GRBs makes these systems a plausible tool to conduct cosmography. We quantify uncertainties in deriving the redshift-dependent DM{sub IGM} as a function of z and test how well dark energy models can be constrained with Monte Carlo simulations. We show that with several tens of FRB/GRB systems potentially detected in a decade or so, one may reach reasonable constraints on wCDM models. When combined with Type Ia supernova (SN Ia) data, unprecedented constraints on the dark energy equation of state may be achieved, thanks to the prospects of detecting FRB/GRB systems at relatively high redshifts. The ratio between the mean value and luminosity distance (D {sub L}(z)) is insensitive to dark energy models. This gives the prospect of applying SN Ia data to calibrate using a relatively small sample of FRB/GRB systems, allowing a reliable constraint on the baryon inhomogeneity distribution as a function of redshift. The methodology developed in this paper can also be applied if the FRB redshifts can be measured by other means. Some caveats of putting this method into practice are also discussed.

  4. Different Types of X-Ray Bursts from GRS 1915+105 and Their Origin

    Science.gov (United States)

    Yadav, J. S.; Rao, A. R.; Agrawal, P. C.; Paul, B.; Seetha, S.; Kasturirangan, K.

    1999-06-01

    We report X-ray observations of the Galactic X-ray transient source GRS 1915+105 with the pointed proportional counters of the Indian X-ray Astronomy Experiment (IXAE) onboard the Indian satellite IRS-P3, which show remarkable richness in temporal variability. The observations were carried out on 1997 June 12-29 and August 7-10, in the energy range of 2-18 keV and revealed the presence of very intense X-ray bursts. All the observed bursts have a slow exponential rise, a sharp linear decay, and broadly can be put in two classes: irregular and quasi-regular bursts in one class, and regular bursts in the other. The regular bursts are found to have two distinct timescales and to persist over extended durations. There is a strong correlation between the preceding quiescent time and the burst duration for the quasi-regular and irregular bursts. No such correlation is found for the regular bursts. The ratio of average flux during the burst time to the average flux during the quiescent phase is high and variable for the quasi-regular and irregular bursts, while it is low and constant for the regular bursts. We present a comprehensive picture of the various types of bursts observed in GRS 1915+105 in the light of the recent theories of advective accretion disks. We suggest that the peculiar bursts that we have seen are characteristic of the change of state of the source. The source can switch back and forth between the low-hard state and the high-soft state near critical accretion rates in a very short timescale, giving rise to the irregular and quasi-regular bursts. The fast timescale for the transition of the state is explained by invoking the appearance and disappearance of the advective disk in its viscous timescale. The periodicity of the regular bursts is explained by matching the viscous timescale with the cooling timescale of the postshock region. A test of the model is presented using the publicly available 13-60 keV RXTE/PCA data for irregular and regular bursts

  5. Energy peaks: A high energy physics outlook

    Science.gov (United States)

    Franceschini, Roberto

    2017-12-01

    Energy distributions of decay products carry information on the kinematics of the decay in ways that are at the same time straightforward and quite hidden. I will review these properties and discuss their early historical applications, as well as more recent ones in the context of (i) methods for the measurement of masses of new physics particle with semi-invisible decays, (ii) the characterization of Dark Matter particles produced at colliders, (iii) precision mass measurements of Standard Model particles, in particular of the top quark. Finally, I will give an outlook of further developments and applications of energy peak method for high energy physics at colliders and beyond.

  6. BROOKHAVEN: High energy gold

    International Nuclear Information System (INIS)

    Bleser, Ed

    1992-01-01

    On April 24, Brookhaven's Alternating Gradient Synchrotron (AGS) started to deliver gold ions at 11.4 GeV per nucleon (2,000 GeV per ion) to experimenters who were delighted not only to receive the world's highest energy gold beam but also to receive it on schedule

  7. Rock Burst Monitoring by Integrated Microseismic and Electromagnetic Radiation Methods

    Science.gov (United States)

    Li, Xuelong; Wang, Enyuan; Li, Zhonghui; Liu, Zhentang; Song, Dazhao; Qiu, Liming

    2016-11-01

    For this study, microseismic (MS) and electromagnetic radiation (EMR) monitoring systems were installed in a coal mine to monitor rock bursts. The MS system monitors coal or rock mass ruptures in the whole mine, whereas the EMR equipment monitors the coal or rock stress in a small area. By analysing the MS energy, number of MS events, and EMR intensity with respect to rock bursts, it has been shown that the energy and number of MS events present a "quiet period" 1-3 days before the rock burst. The data also show that the EMR intensity reaches a peak before the rock burst and this EMR intensity peak generally corresponds to the MS "quiet period". There is a positive correlation between stress and EMR intensity. Buckling failure of coal or rock depends on the rheological properties and occurs after the peak stress in the high-stress concentration areas in deep mines. The MS "quiet period" before the rock burst is caused by the heterogeneity of the coal and rock structures, the transfer of high stress into internal areas, locked patches, and self-organized criticality near the stress peak. This study increases our understanding of coal and rock instability in deep mines. Combining MS and EMR to monitor rock burst could improve prediction accuracy.

  8. LAT Onboard Science: Gamma-Ray Burst Identification

    International Nuclear Information System (INIS)

    Kuehn, Frederick; Hughes, Richard; Smith, Patrick; Winer, Brian; Bonnell, Jerry; Norris, Jay; Ritz, Steven; Russell, James

    2007-01-01

    The main goal of the Large Area Telescope (LAT) onboard science program is to provide quick identification and localization of Gamma Ray Bursts (GRB) onboard the LAT for follow-up observations by other observatories. The GRB identification and localization algorithm will provide celestial coordinates with an error region that will be distributed via the Gamma ray burst Coordinate Network (GCN). We present results that show our sensitivity to bursts as characterized using Monte Carlo simulations of the GLAST observatory. We describe and characterize the method of onboard track determination and the GRB identification and localization algorithm. Onboard track determination is considerably different than in the on-ground case, resulting in a substantially altered point spread function. The algorithm contains tunable parameters which may be adjusted after launch when real bursts characteristics at very high energies have been identified

  9. Broadband Spectral Investigations of Magnetar Bursts

    Science.gov (United States)

    Kırmızıbayrak, Demet; Şaşmaz Muş, Sinem; Kaneko, Yuki; Göğüş, Ersin

    2017-09-01

    We present our broadband (2-250 keV) time-averaged spectral analysis of 388 bursts from SGR J1550-5418, SGR 1900+14, and SGR 1806-20 detected with the Rossi X-ray Timing Explorer (RXTE) here and as a database in a companion web-catalog. We find that two blackbody functions (BB+BB), the sum of two modified blackbody functions (LB+LB), the sum of a blackbody function and a power-law function (BB+PO), and a power law with a high-energy exponential cutoff (COMPT) all provide acceptable fits at similar levels. We performed numerical simulations to constrain the best fitting model for each burst spectrum and found that 67.6% of burst spectra with well-constrained parameters are better described by the Comptonized model. We also found that 64.7% of these burst spectra are better described with the LB+LB model, which is employed in the spectral analysis of a soft gamma repeater (SGR) for the first time here, than with the BB+BB and BB+PO models. We found a significant positive lower bound trend on photon index, suggesting a decreasing upper bound on hardness, with respect to total flux and fluence. We compare this result with bursts observed from SGR and AXP (anomalous X-ray pulsar) sources and suggest that the relationship is a distinctive characteristic between the two. We confirm a significant anticorrelation between burst emission area and blackbody temperature, and find that it varies between the hot and cool blackbody temperatures differently than previously discussed. We expand on the interpretation of our results in the framework of a strongly magnetized neutron star.

  10. Broadband Spectral Investigations of Magnetar Bursts

    Energy Technology Data Exchange (ETDEWEB)

    Kırmızıbayrak, Demet; Şaşmaz Muş, Sinem; Kaneko, Yuki; Göğüş, Ersin, E-mail: demetk@sabanciuniv.edu [Faculty of Engineering and Natural Sciences, Sabancı University, Orhanlı Tuzla, Istanbul 34956 (Turkey)

    2017-09-01

    We present our broadband (2–250 keV) time-averaged spectral analysis of 388 bursts from SGR J1550−5418, SGR 1900+14, and SGR 1806−20 detected with the Rossi X-ray Timing Explorer ( RXTE ) here and as a database in a companion web-catalog. We find that two blackbody functions (BB+BB), the sum of two modified blackbody functions (LB+LB), the sum of a blackbody function and a power-law function (BB+PO), and a power law with a high-energy exponential cutoff (COMPT) all provide acceptable fits at similar levels. We performed numerical simulations to constrain the best fitting model for each burst spectrum and found that 67.6% of burst spectra with well-constrained parameters are better described by the Comptonized model. We also found that 64.7% of these burst spectra are better described with the LB+LB model, which is employed in the spectral analysis of a soft gamma repeater (SGR) for the first time here, than with the BB+BB and BB+PO models. We found a significant positive lower bound trend on photon index, suggesting a decreasing upper bound on hardness, with respect to total flux and fluence. We compare this result with bursts observed from SGR and AXP (anomalous X-ray pulsar) sources and suggest that the relationship is a distinctive characteristic between the two. We confirm a significant anticorrelation between burst emission area and blackbody temperature, and find that it varies between the hot and cool blackbody temperatures differently than previously discussed. We expand on the interpretation of our results in the framework of a strongly magnetized neutron star.

  11. Fine structure in fast drift storm bursts

    International Nuclear Information System (INIS)

    McConnell, D.; Ellis, G.R.A.

    1981-01-01

    Recent observations with high time resolution of fast drift storm (FDS) solar bursts are described. A new variety of FDS bursts characterised by intensity maxima regularly placed in the frequency domain is reported. Possible interpretations of this are mentioned and the implications of the short duration of FDS bursts are discussed. (orig.)

  12. FERMI OBSERVATIONS OF GRB 090510: A SHORT-HARD GAMMA-RAY BURST WITH AN ADDITIONAL, HARD POWER-LAW COMPONENT FROM 10 keV TO GeV ENERGIES

    International Nuclear Information System (INIS)

    Ackermann, M.; Bechtol, K.; Berenji, B.; Blandford, R. D.; Bloom, E. D.; Borgland, A. W.; Bouvier, A.; Asano, K.; Atwood, W. B.; Axelsson, M.; Baldini, L.; Bellazzini, R.; Bregeon, J.; Ballet, J.; Barbiellini, G.; Baring, M. G.; Bastieri, D.; Bhat, P. N.; Bissaldi, E.; Bonamente, E.

    2010-01-01

    We present detailed observations of the bright short-hard gamma-ray burst GRB 090510 made with the Gamma-ray Burst Monitor (GBM) and Large Area Telescope (LAT) on board the Fermi observatory. GRB 090510 is the first burst detected by the LAT that shows strong evidence for a deviation from a Band spectral fitting function during the prompt emission phase. The time-integrated spectrum is fit by the sum of a Band function with E peak = 3.9 ± 0.3 MeV, which is the highest yet measured, and a hard power-law component with photon index -1.62 ± 0.03 that dominates the emission below ∼20 keV and above ∼100 MeV. The onset of the high-energy spectral component appears to be delayed by ∼0.1 s with respect to the onset of a component well fit with a single Band function. A faint GBM pulse and a LAT photon are detected 0.5 s before the main pulse. During the prompt phase, the LAT detected a photon with energy 30.5 +5.8 -2.6 GeV, the highest ever measured from a short GRB. Observation of this photon sets a minimum bulk outflow Lorentz factor, Γ∼> 1200, using simple γγ opacity arguments for this GRB at redshift z = 0.903 and a variability timescale on the order of tens of ms for the ∼100 keV-few MeV flux. Stricter high confidence estimates imply Γ ∼> 1000 and still require that the outflows powering short GRBs are at least as highly relativistic as those of long-duration GRBs. Implications of the temporal behavior and power-law shape of the additional component on synchrotron/synchrotron self-Compton, external-shock synchrotron, and hadronic models are considered.

  13. A first search for coincident gravitational waves and high energy neutrinos using LIGO, Virgo and ANTARES data from 2007

    NARCIS (Netherlands)

    Adrián-Martínez, S.; et al., [Unknown; Decowski, M.P.; Kooijman, P.; Lim, G.; Palioselitis, D.; Presani, E.; de Wolf, E.

    2013-01-01

    We present the results of the first search for gravitational wave bursts associated with high energy neutrinos. Together, these messengers could reveal new, hidden sources that are not observed by conventional photon astronomy, particularly at high energy. Our search uses neutrinos detected by the

  14. A first search for coincident gravitational waves and high energy neutrinos using LIGO, Virgo and ANTARES data from 2007

    NARCIS (Netherlands)

    Adrian-Martinez, S.; Al Samarai, I.; Albert, A.; Andre, M.; Anghinolfi, M.; Anton, G.; Anvar, S.; Ardid, M.; Astraatmadja, T.; Aubert, J-J.; Baret, B.; Basa, S.; Bertin, V.; Biagi, S.; Bigongiari, C.; Bogazzi, C.; Bou-Cabo, M.; Bouhou, B.; Bouwhuis, M.C.; Brunner, J.; Busto, J.; Capone, A.; Arloganu, C. C.; Carr, J.; Cecchini, S.; Charif, Z.; Charvis, Ph.; Chiarusi, T.; Circella, M.; Coniglione, R.; Core, L.; Costantini, H.; Coyle, P.; Creusot, A.; Curtil, C.; De Bonis, G.; Decowski, M. P.; Dekeyser, I.; Deschamps, A.; Distefano, C.; Donzaud, C.; Dornic, D.; Dorosti, Q.; Drouhin, D.; Eberl, T.; Emanuele, U.; Enzenhoefer, A.; Ernenwein, J-P.; Kavatsyuk, O.; Loehner, H.

    We present the results of the first search for gravitational wave bursts associated with high energy neutrinos. Together, these messengers could reveal new, hidden sources that are not observed by conventional photon astronomy, particularly at high energy. Our search uses neutrinos detected by the

  15. High energy cosmic ray astronomy

    International Nuclear Information System (INIS)

    Fonseca, V.

    1996-01-01

    A brief introduction to High Energy Cosmic Ray Astronomy is presented. This field covers a 17 decade energy range (2.10 4 -10 20 ) eV. Recent discoveries done with gamma-ray detectors on-board satellites and ground-based Cherenkov devices are pushing for a fast development of new and innovative techniques, specially in the low energy region which includes the overlapping of satellite and ground-based measurements in the yet unexplored energy range 20 keV-250 GeV. Detection of unexpected extremely high energy events have triggered the interest of the international scientific community. (orig.)

  16. Are there nuclear contributions to gamma ray burst spectra

    International Nuclear Information System (INIS)

    Matz, S.M.; Chupp, E.L.; Forrest, D.J.; Share, G.H.; Nolan, P.L.; Rieger, E.

    1984-01-01

    We have examined the spectra of 38 γ-ray bursts observed by the Gamma Ray Spectrometer (GRS) on the Solar Maximum Mission (SMM) satellite for evidence of a nuclear contribution to the high energy flux. A sum of spectra from the nine bursts with detectable flux >4 MeV suggests but does not require a drop-off above 7 MeV. A cutoff between 7 and 8 MeV is consistent with a high energy spectrum dominated by nuclear lines

  17. High Energy Cosmic Electrons: Messengers from Nearby Cosmic Ray Sources or Dark Matter?

    Science.gov (United States)

    Moiseev, Alexander

    2011-01-01

    This slide presentation reviews the recent discoveries by the Large Area Telescope (LAT) and the Gamma-ray Burst Monitor (GBM) on board the Fermi Gamma-Ray Telescope in reference to high energy cosmic electrons, and whether their source is cosmic rays or dark matter. Specific interest is devoted to Cosmic Ray electrons anisotropy,

  18. High Energy Materials

    Indian Academy of Sciences (India)

    IAS Admin

    Propellants used in rockets, pyrotechnics used in festivities, explosives used for .... In World War II, Wernher von Braun designed the. V-2 rockets which were ... A. Solid Propellants. A solid propellant is made from low or diluted high explosives.

  19. PHYSICAL CONSTRAINTS ON FAST RADIO BURSTS

    Energy Technology Data Exchange (ETDEWEB)

    Luan, Jing; Goldreich, Peter, E-mail: jingluan@caltech.edu [California Institute of Technology, Pasadena, CA 91125 (United States)

    2014-04-20

    Fast radio bursts (FRBs) are isolated, ms radio pulses with dispersion measure (DM) of order 10{sup 3} pc cm{sup –3}. Galactic candidates for the DM of high latitude bursts detected at GHz frequencies are easily dismissed. DM from bursts emitted in stellar coronas are limited by free-free absorption and those from H II regions are bounded by the nondetection of associated free-free emission at radio wavelengths. Thus, if astronomical, FRBs are probably extragalactic. FRB 110220 has a scattering tail of ∼5.6 ± 0.1 ms. If the electron density fluctuations arise from a turbulent cascade, the scattering is unlikely to be due to propagation through the diffuse intergalactic plasma. A more plausible explanation is that this burst sits in the central region of its host galaxy. Pulse durations of order ms constrain the sizes of FRB sources implying high brightness temperatures that indicates coherent emission. Electric fields near FRBs at cosmological distances would be so strong that they could accelerate free electrons from rest to relativistic energies in a single wave period.

  20. PHYSICAL CONSTRAINTS ON FAST RADIO BURSTS

    International Nuclear Information System (INIS)

    Luan, Jing; Goldreich, Peter

    2014-01-01

    Fast radio bursts (FRBs) are isolated, ms radio pulses with dispersion measure (DM) of order 10 3 pc cm –3 . Galactic candidates for the DM of high latitude bursts detected at GHz frequencies are easily dismissed. DM from bursts emitted in stellar coronas are limited by free-free absorption and those from H II regions are bounded by the nondetection of associated free-free emission at radio wavelengths. Thus, if astronomical, FRBs are probably extragalactic. FRB 110220 has a scattering tail of ∼5.6 ± 0.1 ms. If the electron density fluctuations arise from a turbulent cascade, the scattering is unlikely to be due to propagation through the diffuse intergalactic plasma. A more plausible explanation is that this burst sits in the central region of its host galaxy. Pulse durations of order ms constrain the sizes of FRB sources implying high brightness temperatures that indicates coherent emission. Electric fields near FRBs at cosmological distances would be so strong that they could accelerate free electrons from rest to relativistic energies in a single wave period

  1. Numerical Assessment of the Influences of Gas Pressure on Coal Burst Liability

    Directory of Open Access Journals (Sweden)

    Haochen Zhao

    2018-01-01

    Full Text Available When coal mines exploit deep seams with high-gas content, risks are encountered due to the additional high likelihood of rock bursting potential problems. The bursts of coal pillars usually lead to severe fatalities, injuries, and destruction of property, including impeding access to active mine workings underground. The danger exists given that conditions in the already highly brittle coal material can be exacerbated by high stress and high gas pressure conditions. It is thus critical to develop methods that improve current understanding about bursting liability, and techniques to forecast or prevent coal bursting in underground coal mines. This study uses field data from a deep coal mine, and numerical modeling to investigate the effects of gas pressure and mechanical compressive stresses on coal bursting liability in high gas content coal seams. The bursting energy index is adopted to determine the coal bursting liability under high gas pressure conditions. The adopted methodology uses a two-staged approach comprising investigating the influence of gas pressure on the bursting liability of coal pillar, and the influence of the gas pressure on the resulting pillar failure mode. Based on numerical simulations of coal pillars, correlations are observed between the magnitudes of gas pressures and the bursting energy index. Irrespective of pillar size, failure time is shortest when the gas pressure achieves a threshold value between 50 kPa to 70 kPa. At 50 kPa, the value of the BEI increases by 50% going from the 4 m pillar to the 6 m pillar. The value of the BEI increases by 43% going from the 6 m high pillar to the 8 m high pillar at 50 kPa. When pillars fail there is a degree of stress relief leading to a reduction in bursting liability. The results suggest that before 50 kPa, pillar failure is largely due to mechanical loading. After 50 kPa, pillar failure is largely due to excessive gas pressures.

  2. Computing in high energy physics

    International Nuclear Information System (INIS)

    Watase, Yoshiyuki

    1991-01-01

    The increasingly important role played by computing and computers in high energy physics is displayed in the 'Computing in High Energy Physics' series of conferences, bringing together experts in different aspects of computing - physicists, computer scientists, and vendors

  3. Solar Radio Bursts and Space Weather

    Science.gov (United States)

    Gopalswamy, Natchimuthuk,

    2012-01-01

    Radio bursts from the Sun are produced by electron accelerated to relativistic energies by physical processes on the Sun such as solar flares and coronal mass ejections (CMEs). The radio bursts are thus good indicators of solar eruptions. Three types of nonthermal radio bursts are generally associated with CMEs. Type III bursts due to accelerated electrons propagating along open magnetic field lines. The electrons are thought to be accelerated at the reconnection region beneath the erupting CME, although there is another view that the electrons may be accelerated at the CME-driven shock. Type II bursts are due to electrons accelerated at the shock front. Type II bursts are also excellent indicators of solar energetic particle (SEP) events because the same shock is supposed accelerate electrons and ions. There is a hierarchical relationship between the wavelength range of type /I bursts and the CME kinetic energy. Finally, Type IV bursts are due to electrons trapped in moving or stationary structures. The low frequency stationary type IV bursts are observed occasionally in association with very fast CMEs. These bursts originate from flare loops behind the erupting CME and hence indicate tall loops. This paper presents a summary of radio bursts and their relation to CMEs and how they can be useful for space weather predictions.

  4. High-energy communication

    CERN Multimedia

    CERN Communication Group

    2015-01-01

    On Wednesday at 10.40 a.m., the LHC operators declared “stable beams” after two years of technical stop and a few months of commissioning. It was an exciting day for all the teams involved, including those who worked on communicating the news to the public and the media on multiple platforms.   CERN’s most successful tweet on 3 June featured collision images from ALICE, ATLAS, CMS and LHCb and was shared 800 times by the Twitter audience. Live blogging, social media posts, a live webcast, and a constant outpouring of photos and videos: Wednesday morning was a crazy time for the communication teams from CERN, the experiments and various institutes around the world. Even though the event started very early in the morning (the live CCC blog started at 7 a.m. and the live webcast at 8.20 a.m.), the public and the media tuned in to follow and generously cover the start of the LHC’s physics run at an unprecedented energy of 13 TeV. The statistics showed th...

  5. FERMI OBSERVATIONS OF HIGH-ENERGY GAMMA-RAY EMISSION FROM GRB 090217A

    International Nuclear Information System (INIS)

    Ackermann, M.; Ajello, M.; Bechtol, K.; Berenji, B.; Blandford, R. D.; Borgland, A. W.; Bouvier, A.; Baldini, L.; Bellazzini, R.; Bregeon, J.; Brez, A.; Ballet, J.; Barbiellini, G.; Baring, M. G.; Bastieri, D.; Bhat, P. N.; Briggs, M. S.; Bissaldi, E.; Bonamente, E.; Brigida, M.

    2010-01-01

    The Fermi observatory is advancing our knowledge of gamma-ray bursts (GRBs) through pioneering observations at high energies, covering more than seven decades in energy with the two on-board detectors, the Large Area Telescope (LAT) and the Gamma-ray Burst Monitor (GBM). Here, we report on the observation of the long GRB 090217A which triggered the GBM and has been detected by the LAT with a significance greater than 9σ. We present the GBM and LAT observations and on-ground analyses, including the time-resolved spectra and the study of the temporal profile from 8 keV up to ∼1 GeV. All spectra are well reproduced by a Band model. We compare these observations to the first two LAT-detected, long bursts GRB 080825C and GRB 080916C. These bursts were found to have time-dependent spectra and exhibited a delayed onset of the high-energy emission, which are not observed in the case of GRB 090217A. We discuss some theoretical implications for the high-energy emission of GRBs.

  6. Diagnostics from three rising submillimeter bursts

    International Nuclear Information System (INIS)

    Zhou, Ai-Hua; Li, Jian-Ping; Wang, Xin-Dong

    2016-01-01

    In this paper we investigate three novel rising submillimeter (THz) bursts that occurred sequentially in Super Active Region NOAA 10486. The average rising rate of the flux density above 200 GHz is only 20 sfu GHz −1 (corresponding to spectral index α of 1.6) for the THz spectral components of the 2003 October 28 and November 4 bursts, but it attained values of 235 sfu GHz −1 (α = 4.8) in the 2003 November 2 burst. The steeply rising THz spectrum can be produced by a population of highly relativistic electrons with a low-energy cutoff of 1 MeV, but it only requires a low-energy cutoff of 30 keV for the two slowly rising THz bursts, via gyrosynchrotron (GS) radiation based on our numerical simulations of burst spectra in the magnetic dipole field case. The electron density variation is much larger in the THz source than in the microwave (MW) source. It is interesting that the THz source radius decreased by 20%–50% during the decay phase for the three events, but the MW source increased by 28% for the 2003 November 2 event. In the paper we will present a formula that can be used to calculate the energy released by ultrarelativistic electrons, taking the relativistic correction into account for the first time. We find that the energy released by energetic electrons in the THz source exceeds that in the MW source due to the strong GS radiation loss in the THz range, although the modeled THz source area is 3–4 orders smaller than the modeled MW source one. The total energies released by energetic electrons via the GS radiation in radio sources are estimated, respectively, to be 5.2 × 10 33 , 3.9 × 10 33 and 3.7 × 10 32 erg for the October 28, November 2 and 4 bursts, which are 131, 76 and 4 times as large as the thermal energies of 2.9 × 10 31 , 2.1 × 10 31 and 5.2 × 10 31 erg estimated from soft X-ray GOES observations. (paper)

  7. High-energy cosmic rays

    Energy Technology Data Exchange (ETDEWEB)

    Gaisser, Thomas K. [Bartol Research Institute, University of Delaware, Newark, DE 19716 (United States)]. E-mail: gaisser@bartol.udel.edu; Stanev, Todor [Bartol Research Institute, University of Delaware, Newark, DE 19716 (United States)

    2006-10-17

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

  8. Ultra high energy cosmic rays

    International Nuclear Information System (INIS)

    Watson, A.A.

    1986-01-01

    Cosmic radiation was discovered 70 years ago but its origin remains an open question. The background to this problem is outlined and attempts to discover the origin of the most energetic and rarest group above 10 15 eV are described. Measurements of the energy spectrum and arrival direction pattern of the very highest energy particles, mean energy about 6 x 10 19 eV, are used to argue that these particles originate outside our galaxy. Recent evidence from the new field of ultra high energy γ-ray astronomy are discussed in the context of a galactic origin hypothesis for lower energy cosmic rays. (author)

  9. High frequency action potential bursts (≥ 100 Hz) in L2/3 and L5B thick tufted neurons in anaesthetized and awake rat primary somatosensory cortex

    NARCIS (Netherlands)

    C.P.J. de Kock (Christiaan); B. Sakmann (Bert)

    2008-01-01

    textabstractHigh frequency (≥ 100 Hz) bursts of action potentials (APs) generated by neocortical neurons are thought to increase information content and, through back-propagation, to influence synaptic integration and efficacy in distal dendritic compartments. It was recently shown in acute slice

  10. High energy physics

    International Nuclear Information System (INIS)

    Kernan, A.; Shen, B.C.; Ma, E.

    1997-01-01

    Hadron collider studies will focus on: (i) the search for the top quark with the newly installed D0 detector at the Fermilab Tevatron collider, (ii) the upgrade of the D0 detector to match the new main injector luminosity and (iii) R ampersand D on silicon microstrip tracking devices for the SSC. High statistics studies of Z 0 decay will continue with the OPAL detector at LEP. These studies will include a direct measurement of Z decay to neutrinos, the search for Higgs and heavy quark decays of Z. Preparations for the Large Scintillation Neutrino Detector (LSND) to measure neutrino oscillations at LAMPF will focus on data acquisition and testing of photomultiplier tubes. In the theoretical area E. Ma will concentrate on mass-generating radiative mechanisms for light quarks and leptons in renormalizable gauge field theories. J. Wudka's program includes a detailed investigation of the magnetic-flip approach to the solar neutrino

  11. The Terzan 2 Cluster Taken by the High Energy Astronomy Observatory (HEAO)-2

    Science.gov (United States)

    1980-01-01

    The dramatic change in x-ray emission from the Terzan 2 cluster is shown in this series of 2.5-minute exposures taken with the High Energy Astronomy Observatory (HEAO)-2/Einstein Observatory immediately before, during, and after the burst. Total exposure (20 minutes) of the object, including the outburst, is shown in the fourth photograph. These images represent the first observation of an x-ray burst in progress. The actual burst lasted 50 seconds. Among the rarest, and most bizarre, phenomena observed by x-ray astronomers are the so-called cosmic bursters (x-ray sources that suddenly and dramatically increase in intensity then subside). These sudden bursts of intense x-ray radiation apparently come from compact objects with a diameter smaller than 30 miles (48 kilometers). Yet, despite their minuscule size, a typical x-ray burster can release more x-ray energy in a single brief burst than our Sun does in an entire week. The HEAO-2, the first imaging and largest x-ray telescope built to date, was capable of producing actual photographs of x-ray objects. Shortly after launch, the HEAO-2 was nicknamed the Einstein Observatory by its scientific experimenters in honor of the centernial of the birth of Albert Einstein, whose concepts of relativity and gravitation have influenced much of modern astrophysics, particularly x-ray astronomy. The HEAO was designed and developed by TRW, Inc. under the project management of the Marshall Space Flight Center.

  12. Gamma ray bursts: Current status of observations and theory

    International Nuclear Information System (INIS)

    Meegan, C.A.

    1990-04-01

    Gamma ray bursts display a wide range of temporal and spectral characteristics, but typically last several seconds and emit most of their energy in a low energy, gamma ray region. The burst sources appear to be isotropically distributed on the sky. Several lines of evidence suggest magnetic neutron stars as sources for bursts. A variety of energy sources and emission mechanisms are proposed

  13. Microseismic Precursory Characteristics of Rock Burst Hazard in Mining Areas Near a Large Residual Coal Pillar: A Case Study from Xuzhuang Coal Mine, Xuzhou, China

    Science.gov (United States)

    Cao, An-ye; Dou, Lin-ming; Wang, Chang-bin; Yao, Xiao-xiao; Dong, Jing-yuan; Gu, Yu

    2016-11-01

    Identification of precursory characteristics is a key issue for rock burst prevention. The aim of this research is to provide a reference for assessing rock burst risk and determining potential rock burst risk areas in coal mining. In this work, the microseismic multidimensional information for the identification of rock bursts and spatial-temporal pre-warning was investigated in a specific coalface which suffered high rock burst risk in a mining area near a large residual coal pillar. Firstly, microseismicity evolution prior to a disastrous rock burst was qualitatively analysed, and the abnormal clustering of seismic sources, abnormal variations in daily total energy release, and event counts can be regarded as precursors to rock burst. Secondly, passive tomographic imaging has been used to locate high seismic activity zones and assess rock burst hazard when the coalface passes through residual pillar areas. The results show that high-velocity or velocity anomaly regions correlated well with strong seismic activities in future mining periods and that passive tomography has the potential to describe, both quantitatively and periodically, hazardous regions and assess rock burst risk. Finally, the bursting strain energy index was further used for short-term spatial-temporal pre-warning of rock bursts. The temporal sequence curve and spatial contour nephograms indicate that the status of the danger and the specific hazardous zones, and levels of rock burst risk can be quantitatively and rapidly analysed in short time and in space. The multidimensional precursory characteristic identification of rock bursts, including qualitative analysis, intermediate and short-time quantitative predictions, can guide the choice of measures implemented to control rock bursts in the field, and provides a new approach to monitor and forecast rock bursts in space and time.

  14. High energy physics research

    International Nuclear Information System (INIS)

    Piroue, P.A.

    1992-10-01

    The goal of this research is to understand the fundamental constituents of matter and their interactions. At this time, the following activities are underway: e + e - interactions and Z 0 physics at CERN; studies to upgrade the L3 detector at LHC; very high statistics charm physics at Fermilab; search for the H particle at BNL; search for the fifth force; rare kaon decay experiments at BNL; study of B-meson physics at hadron colliders; e + e - pair creation by light at SLAC; R ampersand D related to SSC experiments and the GEM detector; and theoretical research in elementary particle physics and cosmology. The main additions to the activities described in detail in the original grant proposal are (1) an experiment at SLAC (E-144) to study strong-field QED effects in e-laser and γ-laser collisions, and (2) a search for the H particle at BNL (E-188). The R ampersand D efforts for the GEM detector have also considerably expanded. In this paper we give a brief status report for each activity currently under way

  15. High energy physics

    International Nuclear Information System (INIS)

    1992-01-01

    The Counter Group continues to work on data analysis for Fermilab Experiment E653. Altogether, they expect several thousand reconstructed charm events and approximately 25 B pair events of which 12 have been observed thus far. Preparation continue for Fermilab Experiment E781, a high statistics study of charm baryon production. In the Theory Group, Cutkosky and collaborators study hadron phenomenology and non-perturbative QCD calculations. Levine has a long standing program in computational QED to obtain improved theoretical values for g-2 of the electron. Wolfenstein, Li, and their collaborators have worked on areas of weak interaction phenomenology that may yield insights beyond the standard model, e.g. CP violation and non-zero neutrino masses. Holman has been concerned with phase transitions in gauge theories relevant to cosmological problems. During 1991 most of the group effort was concentrated on the L3 experiment at CERN. Highlights of the results from the analysis of the Z degrees resonance include (a) a measurement of the strong coupling constant α s for b quarks (b) a precision measurement of the average time of B hadrons and (c) a direct determination of the number of light neutrino faculties from the reaction e + e - → ν bar νγ. We also began a major upgrade of the L3 luminosity monitor by replacing PWC chamber by a Si strip system in front of the BGO calorimeters. Finally we have continued our SSC R ampersand D work on BaF 2 by joining the GEM collaboration

  16. Conference on High Energy Physics

    CERN Document Server

    2016-01-01

    Conference on High Energy Physics (HEP 2016) will be held from August 24 to 26, 2016 in Xi'an, China. This Conference will cover issues on High Energy Physics. It dedicates to creating a stage for exchanging the latest research results and sharing the advanced research methods. HEP 2016 will be an important platform for inspiring international and interdisciplinary exchange at the forefront of High Energy Physics. The Conference will bring together researchers, engineers, technicians and academicians from all over the world, and we cordially invite you to take this opportunity to join us for academic exchange and visit the ancient city of Xi’an.

  17. Future of high energy physics

    International Nuclear Information System (INIS)

    Panofsky, W.K.H.

    1984-06-01

    A rough overview is given of the expectations for the extension of high energy colliders and accelerators into the xtremely high energy range. It appears likely that the SSC or something like it will be the last gasp of the conventional method of producing high energy proton-proton collisions using synchrotron rings with superconducting magnets. It is likely that LEP will be the highest energy e+e - colliding beam storage ring built. The future beyond that depends on the successful demonstrations of new technologies. The linear collider offers hope in this respect for some extension in energy for electrons, and maybe even for protons, but is too early to judge whether, by how much, or when such an extension will indeed take place

  18. High Energy Transport Code HETC

    International Nuclear Information System (INIS)

    Gabriel, T.A.

    1985-09-01

    The physics contained in the High Energy Transport Code (HETC), in particular the collision models, are discussed. An application using HETC as part of the CALOR code system is also given. 19 refs., 5 figs., 3 tabs

  19. Research in high energy physics

    International Nuclear Information System (INIS)

    1992-01-01

    This report discusses research being conducted in high energy physics in the following areas; quantum chromodynamics; drift chambers; proton-antiproton interactions; particle decays; particle production; polarimeters; quark-gluon plasma; and conformed field theory

  20. Computing in high energy physics

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Sarah; Devenish, Robin [Nuclear Physics Laboratory, Oxford University (United Kingdom)

    1989-07-15

    Computing in high energy physics has changed over the years from being something one did on a slide-rule, through early computers, then a necessary evil to the position today where computers permeate all aspects of the subject from control of the apparatus to theoretical lattice gauge calculations. The state of the art, as well as new trends and hopes, were reflected in this year's 'Computing In High Energy Physics' conference held in the dreamy setting of Oxford's spires. The conference aimed to give a comprehensive overview, entailing a heavy schedule of 35 plenary talks plus 48 contributed papers in two afternoons of parallel sessions. In addition to high energy physics computing, a number of papers were given by experts in computing science, in line with the conference's aim – 'to bring together high energy physicists and computer scientists'.

  1. [Research in high energy physics

    International Nuclear Information System (INIS)

    1991-01-01

    This report discusses progress in the following research in high energy physics: The crystal ball experiment; delco at PEP; proton decay experiment; MACRO detector; mark III detector; SLD detector; CLEO II detector; and the caltech L3 group

  2. Computing in high energy physics

    International Nuclear Information System (INIS)

    Smith, Sarah; Devenish, Robin

    1989-01-01

    Computing in high energy physics has changed over the years from being something one did on a slide-rule, through early computers, then a necessary evil to the position today where computers permeate all aspects of the subject from control of the apparatus to theoretical lattice gauge calculations. The state of the art, as well as new trends and hopes, were reflected in this year's 'Computing In High Energy Physics' conference held in the dreamy setting of Oxford's spires. The conference aimed to give a comprehensive overview, entailing a heavy schedule of 35 plenary talks plus 48 contributed papers in two afternoons of parallel sessions. In addition to high energy physics computing, a number of papers were given by experts in computing science, in line with the conference's aim – 'to bring together high energy physicists and computer scientists'

  3. Problems of high energy physics

    International Nuclear Information System (INIS)

    Kadyshevskij, V.G.

    1989-01-01

    Some problems of high energy physics are discussed. The main attention is paid to describibg the standard model. The model comprises quantum chromodynamics and electroweak interaction theory. The problem of CP breaking is considered as well. 8 refs.; 1 tab

  4. Developments in high energy theory

    Indian Academy of Sciences (India)

    journal of. July 2009 physics pp. 3–60. Developments in high energy theory .... and operated by CERN (European Organization for Nuclear Research), this ma- ...... [2] S Dodelson, Modern cosmology (Academic Press, Amsterdam, 2003).

  5. Research in high energy physics

    International Nuclear Information System (INIS)

    1992-01-01

    This report discusses research being conducted in high energy physics in the following areas: quantum chromodynamics; drift chambers; proton-antiproton interactions; particle decays; particle production; polarimeters; quark-gluon plasma; and conformed field theory

  6. Energy spectrum of tau leptons induced by the high energy Earth-skimming neutrinos

    International Nuclear Information System (INIS)

    Tseng, J.-J.; Yeh, T.-W.; Lee, F.-F.; Lin, G.-L.; Athar, H.; Huang, M.A.

    2003-01-01

    We present a semianalytic calculation of the tau-lepton flux emerging from the Earth induced by incident high energy neutrinos interacting inside the Earth for 10 5 ≤E ν /GeV≤10 10 . We obtain results for the energy dependence of the tau-lepton flux coming from the Earth-skimming neutrinos, because of the neutrino-nucleon charged-current scattering as well as the resonant ν(bar sign) e e - scattering. We illustrate our results for several anticipated high energy astrophysical neutrino sources such as the active galactic nuclei, the gamma-ray bursts, and the Greisen-Zatsepin-Kuzmin neutrino fluxes. The tau-lepton fluxes resulting from rock-skimming and ocean-skimming neutrinos are compared. Such comparisons can render useful information about the spectral indices of incident neutrino fluxes

  7. Solar microwave bursts - A review

    Science.gov (United States)

    Kundu, M. R.; Vlahos, L.

    1982-01-01

    Observational and theoretical results on the physics of microwave bursts that occur in the solar atmosphere are reviewed. Special attention is given to the advances made in burst physics over the last few years with the great improvement in spatial and time resolution, especially with instruments like the NRAO three-element interferometer, the Westerbork Synthesis Radio Telescope, and more recently the Very Large Array. Observations made on the preflare build-up of an active region at centimeter wavelengths are reviewed. Three distinct phases in the evolution of cm bursts, namely the impulsive phase, the post-burst phase, and the gradual rise and fall, are discussed. Attention is also given to the flux density spectra of centimeter bursts. Descriptions are given of observations of fine structures with temporal resolution of 10-100 ms in the intensity profiles of cm-wavelength bursts. High spatial resolution observations are analyzed, with special reference to the one- and two-dimensional maps of cm burst sources.

  8. Powerful Radio Burst Indicates New Astronomical Phenomenon

    Science.gov (United States)

    2007-09-01

    Astronomers studying archival data from an Australian radio telescope have discovered a powerful, short-lived burst of radio waves that they say indicates an entirely new type of astronomical phenomenon. Region of Strong Radio Burst Visible-light (negative greyscale) and radio (contours) image of Small Magellanic Cloud and area where burst originated. CREDIT: Lorimer et al., NRAO/AUI/NSF Click on image for high-resolution file ( 114 KB) "This burst appears to have originated from the distant Universe and may have been produced by an exotic event such as the collision of two neutron stars or the death throes of an evaporating black hole," said Duncan Lorimer, Assistant Professor of Physics at West Virginia University (WVU) and the National Radio Astronomy Observatory (NRAO). The research team led by Lorimer consists of Matthew Bailes of Swinburne University in Australia, Maura McLaughlin of WVU and NRAO, David Narkevic of WVU, and Fronefield Crawford of Franklin and Marshall College in Lancaster, Pennsylvania. The astronomers announced their findings in the September 27 issue of the online journal Science Express. The startling discovery came as WVU undergraduate student David Narkevic re-analyzed data from observations of the Small Magellanic Cloud made by the 210-foot Parkes radio telescope in Australia. The data came from a survey of the Magellanic Clouds that included 480 hours of observations. "This survey had sought to discover new pulsars, and the data already had been searched for the type of pulsating signals they produce," Lorimer said. "We re-examined the data, looking for bursts that, unlike the usual ones from pulsars, are not periodic," he added. The survey had covered the Magellanic Clouds, a pair of small galaxies in orbit around our own Milky Way Galaxy. Some 200,000 light-years from Earth, the Magellanic Clouds are prominent features in the Southern sky. Ironically, the new discovery is not part of these galaxies, but rather is much more distant

  9. A review of gamma ray bursts

    CERN Document Server

    Rees, Martin J

    2000-01-01

    Gamma-ray bursts, an enigma for more than 25 years, are now coming into focus. They involve extraordinary power outputs, and highly relativistic dynamics. The 'trigger' involves stellar-mass compact objects. The most plausible progenitors, ranging from neutron star binary mergers to collapsars (sometimes called 'hypernovae') eventually lead to the formation of a black hole with a torus of hot neutron-density material around it, the extractable energy being up to 10 sup 5 sup 4 ergs. Magnetic fields may exceed 10 sup 1 sup 5 G and particles may be accelerated up to > or approx. 10 sup 2 sup 0 eV. Details of the afterglow may be easier to understand than the initial trigger. Bursts at very high redshift can be astronomically-important as probes of the distant universe.

  10. Active Galactic Nuclei: Sources for ultra high energy cosmic rays?

    International Nuclear Information System (INIS)

    Biermann, Peter L.; Becker, Julia K.; Caramete, Laurentiu; Curutiu, Alex; Engel, Ralph; Falcke, Heino; Gergely, Laszlo A.; Isar, P. Gina; Maris, Ioana C.; Meli, Athina; Kampert, Karl-Heinz; Stanev, Todor; Tascau, Oana; Zier, Christian

    2009-01-01

    The origin of ultra high energy cosmic rays promises to lead us to a deeper understanding of the structure of matter. This is possible through the study of particle collisions at center-of-mass energies in interactions far larger than anything possible with the Large Hadron Collider, albeit at the substantial cost of no control over the sources and interaction sites. For the extreme energies we have to identify and understand the sources first, before trying to use them as physics laboratories. Here we describe the current stage of this exploration. The most promising contenders as sources are radio galaxies and gamma ray bursts. The sky distribution of observed events yields a hint favoring radio galaxies. Key in this quest are the intergalactic and galactic magnetic fields, whose strength and structure are not yet fully understood. Current data and statistics do not yet allow a final judgement. We outline how we may progress in the near future.

  11. Active Galactic Nuclei: Sources for ultra high energy cosmic rays?

    Energy Technology Data Exchange (ETDEWEB)

    Biermann, Peter L. [MPI for Radioastronomy, Bonn (Germany); Dept. of Phys. and Astron., Univ. of Bonn (Germany); Dept. of Phys. and Astr., Univ. of Alabama, Tuscaloosa, AL (United States); Dept. of Phys., Univ. of Alabama at Huntsville, AL (United States); Inst. Nucl. Phys. FZ, Karlsruhe Inst. of Techn. (KIT) (Germany); Becker, Julia K. [Institution foer Fysik, Goeteborgs Univ. (Sweden); Dept. of Phys., Univ. Dortmund, Dortmund (Germany); Caramete, Laurentiu [MPI for Radioastronomy, Bonn (Germany); Institute for Space Studies, Bucharest (Romania); Curutiu, Alex [MPI for Radioastronomy, Bonn (Germany); Engel, Ralph [Inst. Nucl. Phys. FZ, Karlsruhe Inst. of Techn. (KIT) (Germany); Falcke, Heino [Dept. of Astrophys., IMAP, Radboud Univ., Nijmegen (Netherlands); ASTRON, Dwingeloo (Netherlands); Gergely, Laszlo A. [Dept. Appl. Sci., London South Bank University (United Kingdom); Dept. of Theoret. and Exp. Phys., Univ. of Szeged, Szeged (Hungary); Isar, P. Gina [Inst. Nucl. Phys. FZ, Karlsruhe Inst. of Techn. (KIT) (Germany); Institute for Space Studies, Bucharest (Romania); Maris, Ioana C. [Inst. Nucl. Phys. FZ, Karlsruhe Inst. of Techn. (KIT) (Germany); Meli, Athina [Physik. Inst. Univ. Erlangen-Nuernberg (Germany); Kampert, Karl-Heinz [Phys. Dept., Univ. Wuppertal (Germany); Stanev, Todor [Bartol Research Inst., Univ. of Delaware, Newark, DE (United States); Tascau, Oana [Phys. Dept., Univ. Wuppertal (Germany); Zier, Christian [MPI for Radioastronomy, Bonn (Germany); Raman Res. Inst., Bangalore (India)

    2009-05-15

    The origin of ultra high energy cosmic rays promises to lead us to a deeper understanding of the structure of matter. This is possible through the study of particle collisions at center-of-mass energies in interactions far larger than anything possible with the Large Hadron Collider, albeit at the substantial cost of no control over the sources and interaction sites. For the extreme energies we have to identify and understand the sources first, before trying to use them as physics laboratories. Here we describe the current stage of this exploration. The most promising contenders as sources are radio galaxies and gamma ray bursts. The sky distribution of observed events yields a hint favoring radio galaxies. Key in this quest are the intergalactic and galactic magnetic fields, whose strength and structure are not yet fully understood. Current data and statistics do not yet allow a final judgement. We outline how we may progress in the near future.

  12. Observational constraints on multimessenger sources of gravitational waves and high-energy neutrinos.

    Science.gov (United States)

    Bartos, Imre; Finley, Chad; Corsi, Alessandra; Márka, Szabolcs

    2011-12-16

    Many astronomical sources of intense bursts of photons are also predicted to be strong emitters of gravitational waves (GWs) and high-energy neutrinos (HENs). Moreover some suspected classes, e.g., choked gamma-ray bursts, may only be identifiable via nonphoton messengers. Here we explore the reach of current and planned experiments to address this question. We derive constraints on the rate of GW and HEN bursts based on independent observations by the initial LIGO and Virgo GW detectors and the partially completed IceCube (40-string) HEN detector. We then estimate the reach of joint GW+HEN searches using advanced GW detectors and the completed km(3) IceCube detector to probe the joint parameter space. We show that searches undertaken by advanced detectors will be capable of detecting, constraining, or excluding, several existing models with 1 yr of observation. © 2011 American Physical Society

  13. Conversion of zero point energy into high-energy photons

    Energy Technology Data Exchange (ETDEWEB)

    Ivlev, B. I. [Universidad Autonoma de San Luis Potosi, Instituto de Fisica, Av. Manuel Nava No. 6, Zona Universitaria, 78290 San Luis Potosi, SLP (Mexico)

    2016-11-01

    An unusual phenomenon, observed in experiments is studied. X-ray laser bursts of keV energy are emitted from a metal where long-living states, resulting in population inversion, are totally unexpected. Anomalous electron-photon states are revealed to be formed inside the metal. These states are associated with narrow, 10{sup -11} cm, potential well created by the local reduction of zero point electromagnetic energy. In contrast to analogous van der Waals potential well, leading to attraction of two hydrogen atoms, the depth of the anomalous well is on the order of 1 MeV. The states in that well are long-living which results in population inversion and subsequent laser generation observed. The X-ray emission, occurring in transitions to lower levels, is due to the conversion of zero point electromagnetic energy. (Author)

  14. The dynamic behavior of microbubbles during long ultrasound tone-burst excitation: mechanistic insights into ultrasound-microbubble mediated therapeutics using high-speed imaging and cavitation detection

    Science.gov (United States)

    Pacella, John J.; Villanueva, Flordeliza S.

    2015-01-01

    Ultrasound (US)-microbubble (MB) mediated therapies have been shown to restore perfusion and enhance drug/gene delivery. Due to the presumption that MBs do not persist during long US exposure under high acoustic pressures, most schemes utilize short US pulses when a high US pressure is employed. However, we recently observed an enhanced thrombolytic effect using long US pulses at high acoustic pressures. Therefore we explored the fate of MBs during long tone-burst exposures (5 ms) at various acoustic pressures and MB concentrations via direct high-speed optical observation and passive cavitation detection. MBs first underwent stable or inertial cavitation depending on the acoustic pressure, and then formed gas-filled clusters that continued to oscillate, break up, and form new clusters. Cavitation detection confirmed continued, albeit diminishing acoustic activity throughout the 5-ms US excitation. These data suggest that persisting cavitation activity during long tone-bursts may confer additional therapeutic effects. PMID:26603628

  15. The First Fermi-LAT Gamma-Ray Burst Catalog

    NARCIS (Netherlands)

    Ackermann, M.; et al., [Unknown; van der Horst, A.J.

    2013-01-01

    In three years of observations since the beginning of nominal science operations in 2008 August, the Large Area Telescope (LAT) on board the Fermi Gamma-Ray Space Telescope has observed high-energy (gsim 20 MeV) γ-ray emission from 35 gamma-ray bursts (GRBs). Among these, 28 GRBs have been detected

  16. High energy HF pulsed lasers

    International Nuclear Information System (INIS)

    Patterson, E.L.; Gerber, R.A.

    1976-01-01

    Recent experiments show that pulsed HF lasers are capable of producing high energy with good efficiency. Preliminary experiments show that the laser radiation from the high-gain medium can be controlled with a low-power probe laser beam or with low-level feedback. These results indicate that the HF laser may have potential for second-generation laser fusion experiments

  17. The Fermi Gamma-ray Burst Monitor Instrument

    International Nuclear Information System (INIS)

    Bhat, P. N.; Briggs, M. S.; Connaughton, V.; Paciesas, W. S.; Preece, R. D.; Meegan, C. A.; Lichti, G. G.; Diehl, R.; Greiner, J.; Kienlin, A. von; Fishman, G. J.; Kouveliotou, C.; Kippen, R. M.

    2009-01-01

    The Fermi Gamma-ray Space Telescope launched on June 11, 2008 carries two experiments onboard--the Large Area Telescope (LAT) and the Gamma-ray Burst Monitor (GBM). The primary mission of the GBM instrument is to support the LAT in observing γ-ray bursts (GRBs) by providing low-energy measurements with high temporal and spectral resolution as well as rapid burst locations over a large field-of-view (≥8 sr). The GBM will complement the LAT measurements by observing GRBs in the energy range 8 keV to 40 MeV, the region of the spectral turnover in most GRBs. The GBM detector signals are processed by the onboard digital processing unit (DPU). We describe some of the hardware features of the DPU and its expected limitations during intense triggers.

  18. Assessing high wind energy penetration

    DEFF Research Database (Denmark)

    Tande, J.O.

    1995-01-01

    In order to convincingly promote installing wind power capacity as a substantial part of the energy supply system, a set of careful analyses must be undertaken. This paper applies a case study concentrated on assessing the cost/benefit of high wind energy penetration. The case study considers...... expanding the grid connected wind power capacity in Praia, the capital of Cape Verde. The currently installed 1 MW of wind power is estimated to supply close to 10% of the electric energy consumption in 1996. Increasing the wind energy penetration to a higher level is considered viable as the project...... with the existing wind power, supply over 30% of the electric consumption in 1996. Applying the recommended practices for estimating the cost of wind energy, the life-cycle cost of this 2.4 MW investment is estimated at a 7% discount rate and a 20 year lifetime to 0.26 DKK/kW h....

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

    International Nuclear Information System (INIS)

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

    2007-01-01

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

  20. High energy proton PIXE [HEPP

    International Nuclear Information System (INIS)

    McKee, J.S.C.

    1993-01-01

    Studies of particle induced X-ray emission (PIXE) have been widespread and detailed in recent years and despite the fact that most data obtained are from low energy 1-3 MeV experiments, the value of higher energy proton work with its emphasis on K X-ray emission has become more marked as time has progressed. The purpose of this review paper is to outline the history of analysis using high energy protons and to compare and contrast the results obtained with those from lower energy analysis using more firmly established analytical techniques. The work described will concentrate exclusively on proton induced processes and will attempt to outline the rationale for selecting an energy, greater than 20 and up to 70 MeV protons for initiating particles. The relative ease and accuracy of the measurements obtained will be addressed. Clearly such X-ray studies should be seen as complementing low energy work in many instances rather than competing directly with them. However, it will be demonstrated that above a Z value of approximately 20, K X-ray analysis using high energy protons is the only way to go in this type of analysis. (author)

  1. High energy elastic hadron scattering

    International Nuclear Information System (INIS)

    Fearnly, T.A.

    1986-04-01

    The paper deals with the WA7 experiment at the CERN super proton synchrotron (SPS). The elastic differential cross sections of pion-proton, kaon-proton, antiproton-proton, and proton-proton at lower SPS energies over a wide range of momentum transfer were measured. Some theoretical models in the light of the experimental results are reviewed, and a comprehensive impact parameter analysis of antiproton-proton elastic scattering over a wide energy range is presented. A nucleon valence core model for high energy proton-proton and antiproton-proton elastic scattering is described

  2. Are we observing Lorentz violation in gamma ray bursts?

    International Nuclear Information System (INIS)

    Pavlopoulos, Theodore G.

    2005-01-01

    From recent observations of gamma-ray bursts (GRBs), it appears that spectral time lags between higher-energy gamma rays photons and lower-energy photons vary with energy difference and time (distance) traveled. These lags appear to be smaller for the most luminous (close) bursts but larger for the fainter (farther away) bursts. From this observation, it has been suggested that it might be possible to determine the distance (L) these bursts have traveled from these time lags alone, without performing any red-shift measurements. These observed spreads (dispersion) of high-energy electromagnetic pulses of different energies with time contradict the special theory of relativity (STR). However, extended theories (ET) of the STR have been developed that contain a dispersive term, predicting the above observations. An example of such an ET is presented, allowing us to derive a relationship between time lags of gamma rays of different energies and distance L traveled from their origin. In addition, this theory predicts the origin of X-ray flashes

  3. High Energy Physics Departments - Overview

    International Nuclear Information System (INIS)

    Bartke, J.

    1999-01-01

    Following the tradition, the activities of the seven new units created in 1997 on the basis of the former Department of High Energy Physics are presented under a common header, they are: Department of Particle Theory (Dept 5); Department of Leptonic Interactions (Dept 11); Department of Hadron Structure (Dept 12); Department of High Energy Nuclear Interactions (Dept 13); The ALICE Experiment Laboratory (NAL); The ATLAS Experiment Laboratory (NAT); High Energy Physics Detector Construction Group (PBD). The research covers a variety of problems of the experimental and theoretical high energy particle physics: the hadronic and leptonic interactions with nucleons and nuclei (characteristics of particle production, including heavy quark physics), e + e - interactions and tests of the Standard Model (also radiative corrections), ultrarelativistic heavy ion interactions and search for the quark-gluon plasma, as well as the spectra, composition and interactions of high energy cosmic ray particles. Research on detectors and accelerator components as well as the development of the apparatus for the high energy physics experiments at future accelerators: LHC (CERN, Geneva), RHIC (Brookhaven), B-Factory (KEK, Tsukuba) and TESLA (DESY) is also presented. The technology of new materials with unique properties such as carbon-carbon composites is also worked on from the point of view of their application in high energy physics experiments. The Division is located in a separate building on the campus of the University of Mining and Metallurgy (UMM). This location, close to the Jagiellonian University (JU), facilitates the collaboration with the latter and with the UMM. The joint weekly seminars carried out for nearly 40 years prove this long term tradition. A substantial part of the activities is teaching and training students from the academic community in Cracow. Joint research, teaching and academic training in the high energy physics are carried out within the M. Miesowicz

  4. Pulse energy evolution for high-resolution Lamb wave inspection

    International Nuclear Information System (INIS)

    Hua, Jiadong; Zeng, Liang; Gao, Fei; Lin, Jing

    2015-01-01

    Generally, tone burst excitation methods are used to reduce the effect of dispersion in Lamb wave inspection. In addition, algorithms for dispersion compensation are required to simplify responses, especially in long-range inspection. However, the resolution is always limited by the time duration of tone burst excitation. A pulse energy evolution method is established to overcome this limitation. In this method, a broadband signal with a long time (e.g. a chirp, white noise signal, or a pseudo-random sequence) is used as excitation to actuate Lamb waves. First of all, pulse compression is employed to estimate system impulse response with a high signal-to-noise ratio. Then, dispersion compensation is applied repeatedly with systemically varied compensation distances, obtaining a series of compensated signals. In these signals, amplitude (or energy) evolution associated with the change of compensation distance is utilized to estimate the actual propagation distance of the interested wave packet. Finally, the defect position is detected by an imaging algorithm. Several experiments are given to validate the proposed method. (paper)

  5. Coded aperture detector for high precision gamma-ray burst source locations

    International Nuclear Information System (INIS)

    Helmken, H.; Gorenstein, P.

    1977-01-01

    Coded aperture collimators in conjunction with position-sensitive detectors are very useful in the study of transient phenomenon because they combine broad field of view, high sensitivity, and an ability for precise source locations. Since the preceeding conference, a series of computer simulations of various detector designs have been carried out with the aid of a CDC 6400. Particular emphasis was placed on the development of a unit consisting of a one-dimensional random or periodic collimator in conjunction with a two-dimensional position-sensitive Xenon proportional counter. A configuration involving four of these units has been incorporated into the preliminary design study of the Transient Explorer (ATREX) satellite and are applicable to any SAS or HEAO type satellite mission. Results of this study, including detector response, fields of view, and source location precision, will be presented

  6. Strong interactions at high energy

    International Nuclear Information System (INIS)

    Anselmino, M.

    1995-01-01

    Spin effects in strong interaction high energy processes are subtle phenomena which involve both short and long distance physics and test perturbative and non perturbative aspects of QCD. Moreover, depending on quantities like interferences between different amplitudes and relative phases, spin observables always test a theory at a fundamental quantum mechanical level; it is then no surprise that spin data are often difficult to accommodate within the existing models. A report is made on the main issues and contributions discussed in the parallel Session on the open-quote open-quote Strong interactions at high energy close-quote close-quote in this Conference. copyright 1995 American Institute of Physics

  7. Winter time burst of CO2 from the High Arctic soils of Svalbard

    DEFF Research Database (Denmark)

    Friborg, Thomas; Hansen, Birger; Elberling, Bo

    of relatively few measurements which appear to give small and constant emission rates. Further, most studies of the processes behind winter time emission of CO2 conclude that the flux during this time of year can be linked to the respiratory release of CO2 from soil micro organisms, which is temperature...... the winter at a high arctic location in Svalbard (78°N). Measurements were conducted in the field during the winter season of 2004-2005 and show reliable and continuous measurements of CO2 fluxes down to a level of 0.01 ìmol m-2 s-1 and good correspondence with other types of soil chambers. Our results...... indicate that a substantial part of the annual CO2 emission from the ecosystem occur during the freeze in period, where more CO2 is emitted from the soil over a few weeks than the accumulated flux for the rest of the winter. During the coldest part of the...

  8. Material Surface Damage under High Pulse Loads Typical for ELM Bursts and Disruptions in ITER

    Energy Technology Data Exchange (ETDEWEB)

    Landman, I.S.; Pestchanyi, S.E.; Bazylev, B.N [Forschungszentrum Karlsruhe (Germany). Inst. for Pulsed Power and Microwave Technology; Safronov, V.M. [Troitsk Inst. for Innovation and Fusion Research (TRINITI) (Russian Federation); Garkusha, I.E. [Kharkov Inst. of Physics and Technology (KIPT) (Ukraine). Inst. of Plasma Physics

    2004-08-01

    The divertor armour material for the tokamak ITER will probably be carbon manufactured as fibre composites (CFC) and tungsten as either brush-like structures or thin plates. Disruptive pulse loads where the heat deposition Q may reach 10{sup 2} MJ/m{sup 2} on a time scale {tau} of 3 ms, or operation in the ELMy H-mode at repetitive loads with Q {approx} 3MJ/m{sup 2} and {tau}{approx}0.3 ms; deteriorate armour performance. This work surveys recent numerical and experimental investigations of erosion mechanisms at these off-normal regimes carried out at FZK, TRINITI, and IPP-Kharkov. The modelling uses the anisotropic thermomechanics code PEGASUS-3D for the simulation of CFC brittle destruction, the surface melt motion code MEMOS-1.5D for tungsten targets, and the radiation-magnetohydrodynamics code FOREV-2D for calculating the plasma impact and simulating the heat loads for the ITER regime. Experiments aimed at validating these codes are being carried out at the plasma gun facilities MK-200UG, QSPA-T, and QSPA-Kh50 which produce powerful streams of hydrogen plasma with Q=10-30MJ/m{sup 2} and {tau} = 0.03-0.5 ms. Essential results are, for CFC targets, the experiments at high heat loads and the development of a local overheating model incorporated in PEGASUS-3D, and for the tungsten targets the analysis of evaporation- and melt motion erosion on the base of MEMOS-1.5D calculations for repetitive ELMs.

  9. Material Surface Damage under High Pulse Loads Typical for ELM Bursts and Disruptions in ITER

    Science.gov (United States)

    Landman, I. S.; Pestchanyi, S. E.; Safronov, V. M.; Bazylev, B. N.; Garkusha, I. E.

    The divertor armour material for the tokamak ITER will probably be carbon manufactured as fibre composites (CFC) and tungsten as either brush-like structures or thin plates. Disruptive pulse loads where the heat deposition Q may reach 102 MJ/m 2 on a time scale Ïä of 3 ms, or operation in the ELMy H-mode at repetitive loads with Q âe 1/4 3 MJ/m2 and Ïä âe 1/4 0.3 ms, deteriorate armour performance. This work surveys recent numerical and experimental investigations of erosion mechanisms at these off-normal regimes carried out at FZK, TRINITI, and IPP-Kharkov. The modelling uses the anisotropic thermomechanics code PEGASUS-3D for the simulation of CFC brittle destruction, the surface melt motion code MEMOS-1.5D for tungsten targets, and the radiation-magnetohydrodynamics code FOREV-2D for calculating the plasma impact and simulating the heat loads for the ITER regime. Experiments aimed at validating these codes are being carried out at the plasma gun facilities MK-200UG, QSPA-T, and QSPA-Kh50 which produce powerful streams of hydrogen plasma with Q = 10–30 MJ/m2 and Ïä = 0.03–0.5 ms. Essential results are, for CFC targets, the experiments at high heat loads and the development of a local overheating model incorporated in PEGASUS-3D, and for the tungsten targets the analysis of evaporation- and melt motion erosion on the base of MEMOS-1.5D calculations for repetitive ELMs.

  10. Radio Flares from Gamma-ray Bursts

    Science.gov (United States)

    Kopač, D.; Mundell, C. G.; Kobayashi, S.; Virgili, F. J.; Harrison, R.; Japelj, J.; Guidorzi, C.; Melandri, A.; Gomboc, A.

    2015-06-01

    We present predictions of centimeter and millimeter radio emission from reverse shocks (RSs) in the early afterglows of gamma-ray bursts (GRBs) with the goal of determining their detectability with current and future radio facilities. Using a range of GRB properties, such as peak optical brightness and time, isotropic equivalent gamma-ray energy, and redshift, we simulate radio light curves in a framework generalized for any circumburst medium structure and including a parameterization of the shell thickness regime that is more realistic than the simple assumption of thick- or thin-shell approximations. Building on earlier work by Mundell et al. and Melandri et al. in which the typical frequency of the RS was suggested to lie at radio rather than optical wavelengths at early times, we show that the brightest and most distinct RS radio signatures are detectable up to 0.1-1 day after the burst, emphasizing the need for rapid radio follow-up. Detection is easier for bursts with later optical peaks, high isotropic energies, lower circumburst medium densities, and at observing frequencies that are less prone to synchrotron self-absorption effects—typically above a few GHz. Given recent detections of polarized prompt gamma-ray and optical RS emission, we suggest that detection of polarized radio/millimeter emission will unambiguously confirm the presence of low-frequency RSs at early time.

  11. RADIO FLARES FROM GAMMA-RAY BURSTS

    International Nuclear Information System (INIS)

    Kopač, D.; Mundell, C. G.; Kobayashi, S.; Virgili, F. J.; Harrison, R.; Japelj, J.; Gomboc, A.; Guidorzi, C.; Melandri, A.

    2015-01-01

    We present predictions of centimeter and millimeter radio emission from reverse shocks (RSs) in the early afterglows of gamma-ray bursts (GRBs) with the goal of determining their detectability with current and future radio facilities. Using a range of GRB properties, such as peak optical brightness and time, isotropic equivalent gamma-ray energy, and redshift, we simulate radio light curves in a framework generalized for any circumburst medium structure and including a parameterization of the shell thickness regime that is more realistic than the simple assumption of thick- or thin-shell approximations. Building on earlier work by Mundell et al. and Melandri et al. in which the typical frequency of the RS was suggested to lie at radio rather than optical wavelengths at early times, we show that the brightest and most distinct RS radio signatures are detectable up to 0.1–1 day after the burst, emphasizing the need for rapid radio follow-up. Detection is easier for bursts with later optical peaks, high isotropic energies, lower circumburst medium densities, and at observing frequencies that are less prone to synchrotron self-absorption effects—typically above a few GHz. Given recent detections of polarized prompt gamma-ray and optical RS emission, we suggest that detection of polarized radio/millimeter emission will unambiguously confirm the presence of low-frequency RSs at early time

  12. High-energy atomic physics

    CERN Document Server

    Drukarev, Evgeny G

    2016-01-01

    This self-contained text introduces readers to the field of high-energy atomic physics - a new regime of photon-atom interactions in which the photon energies significantly exceed the atomic or molecular binding energies, and which opened up with the recent advent of new synchrotron sources. From a theoretical point of view, a small-parameter characteristic of the bound system emerged, making it possible to perform analytic perturbative calculations that can in turn serve as benchmarks for more powerful numerical computations. The first part of the book introduces readers to the foundations of this new regime and its theoretical treatment. In particular, the validity of the small-parameter perturbation expansion and of the lowest-order approximation is critically reviewed. The following chapters then apply these insights to various atomic processes, such as photoionization as a many-body problem, dominant mechanisms for the production of ions at higher energies, Compton scattering and ionization accompanied b...

  13. The gluon condensation at high energy hadron collisions

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Wei, E-mail: weizhu@mail.ecnu.edu.cn [Department of Physics, East China Normal University, Shanghai 200241 (China); Lan, Jiangshan [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

    2017-03-15

    We report that the saturation/CGC model of gluon distribution is unstable under action of the chaotic solution in a nonlinear QCD evolution equation, and it evolves to the distribution with a sharp peak at the critical momentum. We find that this gluon condensation is caused by a new kind of shadowing–antishadowing effects, and it leads to a series of unexpected effects in high energy hadron collisions including astrophysical events. For example, the extremely intense fluctuations in the transverse-momentum and rapidity distributions of the gluon jets present the gluon-jet bursts; a sudden increase of the proton–proton cross sections may fill the GZK suppression; the blocking QCD evolution will restrict the maximum available energy of the hadron–hadron colliders.

  14. Solar Drift-Pair Bursts

    Science.gov (United States)

    Stanislavsky, A.; Volvach, Ya.; Konovalenko, A.; Koval, A.

    2017-08-01

    In this paper a new sight on the study of solar bursts historically called drift pairs (DPs) is presented. Having a simple morphology on dynamic spectra of radio records (two short components separated in time, and often they are very similar) and discovered at the dawn of radio astronomy, their features remain unexplained totally up to now. Generally, the DPs are observed during the solar storms of type III bursts, but not every storm of type III bursts is linked with DPs. Detected by ground-based instruments at decameter and meter wavelengths, the DP bursts are limited in frequency bandwidth. They can drift from high frequencies to low ones and vice versa. Their frequency drift rate may be both lower and higher than typical rates of type III bursts at the same frequency range. The development of low-frequency radio telescopes and data processing provide additional possibilities in the research. In this context the fresh analysis of DPs, made from recent observations in the summer campaign of 2015, are just considered. Their study was implemented by updated tools of the UTR-2 radio telescope at 9-33 MHz. During 10-12 July of 2015, DPs forming the longest patterns on dynamic spectra are about 7% of the total number of recorded DPs. Their marvelous resemblance in frequency drift rates with the solar S-bursts is discussed.

  15. VERITAS OBSERVATIONS OF GAMMA-RAY BURSTS DETECTED BY SWIFT

    International Nuclear Information System (INIS)

    Acciari, V. A.; Benbow, W.; Aliu, E.; Errando, M.; Arlen, T.; Aune, T.; Beilicke, M.; Buckley, J. H.; Bugaev, V.; Bradbury, S. M.; Byrum, K.; Cannon, A.; Collins-Hughes, E.; Cesarini, A.; Connolly, M. P.; Christiansen, J. L.; Ciupik, L.; Cui, W.; Duke, C.; Falcone, A.

    2011-01-01

    We present the results of 16 Swift-triggered Gamma-ray burst (GRB) follow-up observations taken with the Very Energetic Radiation Imaging Telescope Array System (VERITAS) telescope array from 2007 January to 2009 June. The median energy threshold and response time of these observations were 260 GeV and 320 s, respectively. Observations had an average duration of 90 minutes. Each burst is analyzed independently in two modes: over the whole duration of the observations and again over a shorter timescale determined by the maximum VERITAS sensitivity to a burst with a t –1.5 time profile. This temporal model is characteristic of GRB afterglows with high-energy, long-lived emission that have been detected by the Large Area Telescope on board the Fermi satellite. No significant very high energy (VHE) gamma-ray emission was detected and upper limits above the VERITAS threshold energy are calculated. The VERITAS upper limits are corrected for gamma-ray extinction by the extragalactic background light and interpreted in the context of the keV emission detected by Swift. For some bursts the VHE emission must have less power than the keV emission, placing constraints on inverse Compton models of VHE emission.

  16. A theory for narrow-banded radio bursts at Uranus - MHD surface waves as an energy driver

    Science.gov (United States)

    Farrell, W. M.; Curtis, S. A.; Desch, M. D.; Lepping, R. P.

    1992-01-01

    A possible scenario for the generation of the narrow-banded radio bursts detected at Uranus by the Voyager 2 planetary radio astronomy experiment is described. In order to account for the emission burstiness which occurs on time scales of hundreds of milliseconds, it is proposed that ULF magnetic surface turbulence generated at the frontside magnetopause propagates down the open/closed field line boundary and mode-converts to kinetic Alfven waves (KAW) deep within the polar cusp. The oscillating KAW potentials then drive a transient electron stream that creates the bursty radio emission. To substantiate these ideas, Voyager 2 magnetometer measurements of enhanced ULF magnetic activity at the frontside magnetopause are shown. It is demonstrated analytically that such magnetic turbulence should mode-convert deep in the cusp at a radial distance of 3 RU.

  17. Gamma-ray burst observations with new generation imaging atmospheric Cerenkov Telescopes in the FERMI era

    International Nuclear Information System (INIS)

    Covino, S.; Campana, S.; Garczarczyk, M.; Galante, N.; Gaug, M.; Antonelli, A.; Bastieri, D.; Longo, F.; Scapin, V.

    2009-01-01

    After the launch and successful beginning of operations of the FERMI satellite, the topics related to high-energy observations of gamma-ray bursts have obtained a considerable attention by the scientific community. Undoubtedly, the diagnostic power of high-energy observations in constraining the emission processes and the physical conditions of gamma-ray burst is relevant. We briefly discuss how gamma-ray burst observations with ground-based imaging array Cerenkov telescopes, in the GeV-TeV range, can compete and cooperate with FERMI observations, in the MeV-GeV range, to allow researchers to obtain a more detailed and complete picture of the prompt and afterglow phases of gamma-ray bursts.

  18. Multiprocessors for high energy physics

    International Nuclear Information System (INIS)

    Pohl, M.

    1987-01-01

    I review the role, status and progress of multiprocessor projects relevant to high energy physics. A short overview of the large variety of multiprocessors architectures is given, with special emphasis on machines suitable for experimental data reconstruction. A lot of progress has been made in the attempt to make the use of multiprocessors less painful by creating a ''Parallel Programming Environment'' supporting the non-expert user. A high degree of usability has been reached for coarse grain (event level) parallelism. The program development tools available on various systems (subroutine packages, preprocessors and parallelizing compilers) are discussed in some detail. Tools for execution control and debugging are also developing, thus opening the path from dedicated systems for large scale, stable production towards support of a more general job mix. At medium term, multiprocessors will thus cover a growing fraction of the typical high energy physics computing task. (orig.)

  19. Instrumentation in high energy physics

    International Nuclear Information System (INIS)

    Serin, L.

    2007-01-01

    The instrumentation in high energy physics is a wide and advanced domain which cannot be covered in a single lesson. The main basic physics processes for charged and neutral particles are recalled with the definition of a few concepts needed to understand or design a detector. The application of these principles to charged particle measurement devices (momentum), light detection or energy measurement are presented mostly with examples from collider experiments. The particle identification which is often the combination of different techniques in a same experiment is also discussed. Finally in a very short section, a few considerations about electronics/processing with their impact on the detector performance are given

  20. Cosmic gamma bursts

    International Nuclear Information System (INIS)

    Ehstulin, I.V.

    1980-01-01

    A brief consideration is being given to the history of cosmic gamma burst discovery and modern knowledge of their properties. The time dependence of gamma bursts is described and their possible sources are discussed

  1. High energy particle experiment for the GEOTAIL mission

    International Nuclear Information System (INIS)

    1989-09-01

    The high energy particle experiment for GEOTAIL mission was designed to understand the particle acceleration mechanism, energy flow, boundary dynamics and magnetic reconnection mechanism in the geotail region, solar flare particle acceleration mechanism, the propagation mechanism through interplanetary space, and the origin, lifetime and propagation mechanism of cosmic ray heavy ions. In order to achieve these objectives, particle detectors, burst detectors, medium energy isotope telescopes and a high energy isotope telescope will be placed in the spacecraft which will be launched in 1992 as one of the spacecraft missions in the International Solar Terrestrial Physics program. With these detectors, electrons, protons and helium, carbon, silicon and iron particles will be detected. The characteristics and the main technique used for each instrument to observe high energy particles are summarized. The details of the scientific objectives, the basic principle of particle identification, the electronic system and data processing system, key parameter information, telemetry data formats, preflight and in-flight calibration method and data an analysis plan are described in this report. (K.I.)

  2. Cosmic gamma-ray bursts

    International Nuclear Information System (INIS)

    Hurley, K.

    1989-01-01

    This paper reviews the essential aspects of the gamma-ray burst (GRB) phenomenon, with emphasis on the more recent results. GRBs are introduced by their time histories, which provide some evidence for a compact object origin. The energy spectra of bursts are presented and they are seen to demonstrate practically unambiguously that the origin of some GRBs involves neutron stars. Counterpart searches are reviewed briefly and the statistical properties of bursters treated. This paper presents a review of the three known repeating bursters (the Soft Gamma Repeaters). Extragalactic and galactic models are discussed and future prospects are assessed

  3. Computing in high energy physics

    International Nuclear Information System (INIS)

    Hertzberger, L.O.; Hoogland, W.

    1986-01-01

    This book deals with advanced computing applications in physics, and in particular in high energy physics environments. The main subjects covered are networking; vector and parallel processing; and embedded systems. Also examined are topics such as operating systems, future computer architectures and commercial computer products. The book presents solutions that are foreseen as coping, in the future, with computing problems in experimental and theoretical High Energy Physics. In the experimental environment the large amounts of data to be processed offer special problems on-line as well as off-line. For on-line data reduction, embedded special purpose computers, which are often used for trigger applications are applied. For off-line processing, parallel computers such as emulator farms and the cosmic cube may be employed. The analysis of these topics is therefore a main feature of this volume

  4. Harvard University High Energy Physics

    International Nuclear Information System (INIS)

    1993-01-01

    The mainly experimental research program in high energy physics at Harvard is summarized in a descriptive fashion according to the following outline: Proton endash antiproton colliding beam program at Fermilab -- CDF (forward/backward electromagnetic calorimeters -- FEM, central muon extension -- CMX, gas calorimetry and electronics development, front-end electronics upgrades, software development, physics analysis, timetable), electron -- positron collisions in the upsilon region -- CLEO (the hardware projects including CLEO II barrel TOF system and silicon drift detector R ampersand D, physics analysis), search for ν μ to ν τ oscillations with the NOMAD experiment at CERN, the solenoidal detector collaboration at the SSC, muon scattering at FNAL -- E665, the L3 experiment, and phenomenological analysis of high-energy bar pp cross sections. 149 refs

  5. A high energy physics perspective

    International Nuclear Information System (INIS)

    Marciano, W.J.

    1997-01-01

    The status of the Standard model and role of symmetry in its development are reviewed. Some outstanding problems are surveyed and possible solutions in the form of additional open-quotes Hidden Symmetries close quotes are discussed. Experimental approaches to uncover open-quotes New Physicsclose quotes associated with those symmetries are described with emphasis on high energy colliders. An outlook for the future is given

  6. [Research in high energy physics

    International Nuclear Information System (INIS)

    LoSecco, J.

    1989-01-01

    We review the efforts of the Notre Dame non accelerator high energy physics group. Our major effort has been directed toward the IMB deep underground detector. Since the departure of the Michigan group our responsibilities to the group have grown. We are also very active in pursuing physics with the IMB 3 detector. Currently we are studying proton decay, point neutrino sources and neutrino oscillations with the contained event sample

  7. Cosmology for high energy physicists

    International Nuclear Information System (INIS)

    Albrecht, A.

    1987-11-01

    The standard big bang model of cosmology is presented. Although not perfect, its many successes make it a good starting point for most discussions of cosmology. Places are indicated where well understood laboratory physics is incorporated into the big bang, leading to successful predictions. Much less established aspects of high energy physics and some of the new ideas they have introduced into the field of cosmology are discussed, such as string theory, inflation and monopoles. 49 refs., 5 figs

  8. High Energy Physics in Europe

    International Nuclear Information System (INIS)

    Anon.

    1980-01-01

    A thorough survey of the present and possible future activities and resources in high energy physics in the CERN Member States has been carried out by a Working Group of ECFA (European Committee for Future Accelerators) under the Chairmanship of John Mulvey. The aim has been to obtain a view of the present European scene and to see whether it looks well adapted to the effective exploitation of possible future machines in Europe (particular LEP) and the rest of the world

  9. Gamma ray bursts of black hole universe

    Science.gov (United States)

    Zhang, T. X.

    2015-07-01

    Slightly modifying the standard big bang theory, Zhang recently developed a new cosmological model called black hole universe, which has only a single postulate but is consistent with Mach's principle, governed by Einstein's general theory of relativity, and able to explain existing observations of the universe. In the previous studies, we have explained the origin, structure, evolution, expansion, cosmic microwave background radiation, quasar, and acceleration of black hole universe, which grew from a star-like black hole with several solar masses through a supermassive black hole with billions of solar masses to the present state with hundred billion-trillions of solar masses by accreting ambient matter and merging with other black holes. This study investigates gamma ray bursts of black hole universe and provides an alternative explanation for the energy and spectrum measurements of gamma ray bursts according to the black hole universe model. The results indicate that gamma ray bursts can be understood as emissions of dynamic star-like black holes. A black hole, when it accretes its star or merges with another black hole, becomes dynamic. A dynamic black hole has a broken event horizon and thus cannot hold the inside hot (or high-frequency) blackbody radiation, which flows or leaks out and produces a GRB. A star when it collapses into its core black hole produces a long GRB and releases the gravitational potential energy of the star as gamma rays. A black hole that merges with another black hole produces a short GRB and releases a part of their blackbody radiation as gamma rays. The amount of energy obtained from the emissions of dynamic star-like black holes are consistent with the measurements of energy from GRBs. The GRB energy spectra derived from this new emission mechanism are also consistent with the measurements.

  10. High energy electron positron physics

    International Nuclear Information System (INIS)

    Ali, A.; Soding, P.

    1987-01-01

    With the termination of the physics program at PETRA in a year from now, and with the start of TRISTAN and the SLC and later LEP, an era of e/sup +/e/sup -/ physics will come to an end and a new one begins. The field is changing from a field of a few specialists, to becoming one of the mainstream efforts of the high energy community. It seems appropriate at this moment to summarize what has been learned over the past years, in a way more useful to any high energy physicist in particular to newcomers in the e/sup +/e/sup -/ field. This is the purpose of the book. This book should be used as a reference for future workers in the field of e/sup +/e/sup -/ interactions. It includes the most relevant data, parametrizations, theoretical background, and a chapter on detectors. Contents: Foreword; Detectors for High Energy e/sup +/e/sup -/ Physics; Lepton Pair Production and Electroweak Parameters; Hadron Production, Strong and Electroweak Properties; tau Physics; Recent Results on the Charm Sector; Bottom Physics; Lifetime Measurements of tau, Charmed and Beauty Hadrons; Υ Spectroscopy; Hadronic Decays of the Υ; Quark and Gluon Fragmentation in the e/sup +/e/sup -/ Continuum; Jet Production and QCD; Two Photon Physics; Search for New Particles

  11. Astrophysics at very high energies

    International Nuclear Information System (INIS)

    Aharonian, Felix; Bergstroem, Lars; Dermer, Charles

    2013-01-01

    Presents three complementary lectures on very-high-energy astrophysics given by worldwide leaders in the field. Reviews the recent advances in and prospects of gamma-ray astrophysics and of multi-messenger astronomy. Prepares readers for using space and ground-based gamma-ray observatories, as well as neutrino and other multi-messenger detectors. With the success of Cherenkov Astronomy and more recently with the launch of NASA's Fermi mission, very-high-energy astrophysics has undergone a revolution in the last years. This book provides three comprehensive and up-to-date reviews of the recent advances in gamma-ray astrophysics and of multi-messenger astronomy. Felix Aharonian and Charles Dermer address our current knowledge on the sources of GeV and TeV photons, gleaned from the precise measurements made by the new instrumentation. Lars Bergstroem presents the challenges and prospects of astro-particle physics with a particular emphasis on the detection of dark matter candidates. The topics covered by the 40th Saas-Fee Course present the capabilities of current instrumentation and the physics at play in sources of very-high-energy radiation to students and researchers alike. This book will encourage and prepare readers for using space and ground-based gamma-ray observatories, as well as neutrino and other multi-messenger detectors.

  12. High Energy Physics Departments - Overview

    International Nuclear Information System (INIS)

    Bartke, J.

    2000-01-01

    Full text: Following our long-time tradition we will present under a common header the activities of the seven new units created in 1997 on the basis of the former Department of High Energy Physics: Department of Particle Theory (Dept. V); Department of Leptonic Interactions (Dept XI); Department of Hadron Structure (Dept XII); Department of High Energy Nuclear Interactions (Dept XIII); The ALICE Experiment Laboratory (NAL); The ATLAS Experiment Laboratory (NAT); High Energy Physics Detector Construction Group (PBD). At the end we will list our common activities: lectures and courses as well as seminars. Our research covers a variety of problems of the experimental and theoretical high energy particle physics: the hadronic and leptonic interactions with nucleons and nuclei (characteristics of particle production, including heavy quark physics), e + e - interactions and tests of the Standard Model (also evaluation of radiative corrections), ultrarelativistic heavy ion interactions and search for the quark-gluon plasma, as well as the spectra, composition and interactions of high energy cosmic ray particles. Research on detectors and accelerator components as well as the development of the apparatus for the high energy physics experiments at future accelerators: LHC (CERN, Geneva), RHIC (Brookhaven), B-Factory (KEK, Tsukuba) and TESLA (DESY, Hamburg) is also carried out. The technology of new materials with unique properties such as carbon-carbon composites is also worked on from the point of view of their application in high energy physics experiments. The Division is located in a separate building on the campus of the University of Mining and Metallurgy. This location, close to the Jagiellonian University, facilitates the collaboration with the latter and with the University of Mining and Metallurgy. The joint weekly seminars carried out for nearly 40 years prove this long term tradition. A substantial part of our activities is teaching and training students from

  13. Quantum chromodynamics at high energy

    CERN Document Server

    Kovchegov, Yuri V

    2012-01-01

    Filling a gap in the current literature, this book is the first entirely dedicated to high energy QCD including parton saturation. It presents groundbreaking progress on the subject and describes many of the problems at the forefront of research, bringing postgraduate students, theorists and advanced experimentalists up to date with the current status of the field. A broad range of topics in high energy QCD are covered, most notably on the physics of parton saturation and the Color Glass Condensate (CGC). The material is presented in a pedagogical way, with numerous examples and exercises. Discussion ranges from the quasi-classical McLerran–Venugopalan model to the linear and non-linear BFKL/BK/JIMWLK small-x evolution equations. The authors adopt both a theoretical and experimental outlook and present the physics of strong interactions in a universal way, making it useful to physicists from various sub-communities and applicable to processes studied at high energy accelerators around the world.

  14. Fast Fourier transformation results from gamma-ray burst profiles

    Science.gov (United States)

    Kouveliotou, Chryssa; Norris, Jay P.; Fishman, Gerald J.; Meegan, Charles A.; Wilson, Robert B.; Paciesas, W. S.

    1992-01-01

    Several gamma-ray bursts in the BATSE data have sufficiently long durations and complex temporal structures with pulses that appear to be spaced quasi-periodically. In order to test and quantify these periods we have applied fast Fourier transformations (FFT) to all these events. We have also performed cross spectral analyses of the FFT of the two extreme (high-low) energy bands in each case to determine the lead/lag of the pulses in different energies.

  15. High energy overcurrent protective device

    Science.gov (United States)

    Praeg, Walter F.

    1982-01-01

    Electrical loads connected to capacitance elements in high voltage direct current systems are protected from damage by capacitance discharge overcurrents by connecting between the capacitance element and the load, a longitudinal inductor comprising a bifilar winding wound about a magnetic core, which forms an incomplete magnetic circuit. A diode is connected across a portion of the bifilar winding which conducts a unidirectional current only. Energy discharged from the capacitance element is stored in the inductor and then dissipated in an L-R circuit including the diode and the coil winding. Multiple high voltage circuits having capacitance elements may be connected to loads through bifilar windings all wound about the aforementioned magnetic core.

  16. Department of High Energy Physics: Overview

    International Nuclear Information System (INIS)

    Bialkowska, H.

    2004-01-01

    Full text: The activities of the Department of High Energy Physics are centered around experiments performed at accelerators in the following laboratories: - At CERN, the European Laboratory for Particle Physics in Geneva, Switzerland: - DELPHI at LEP e + e - storage ring - the tests of the Standard Model, b-quark physics, gamma-gamma interactions and search for Higgs boson and supersymmetric particles; - NA4B - the CP-violation and rare K 0 decays; - COMPASS (Compact Muon and Proton Apparatus for Structure and Spectroscopy) - studies the gluon polarization in the nucleon; - NA49 and WA98 - heavy ion physics, looking for possible effects of the phase transition to the quark-gluon plasma state. At CELSIUS Storage Ring in Uppsala, Sweden: - WASA - a precise study of near threshold resonance production. - At RHIC - study of pp elastic scattering. - At DESY in Hamburg, Germany: - ZEUS - deep inelastic scattering of electrons and protons, proton structure functions, diffractive photon-photon interactions. - Super-Kamiokande and K2 K - a study of neutrino oscillations. The groups from our Department participated in the construction phase of the experiments, both in hardware and in development of the software used in data analysis. Presently they take part in the data collection, detector performance supervision and data analysis. The Department is also involved in the preparation of new experiments: - search for optical flashes of cosmic origin: ''π of the sky'' project - search for optical counterparts of γ ray bursts, - CMS (Compact Muon Solenoid) at the LHC, - LHCb (b-quark production and CP-violation) at the LHC (Large Hadron Collider) at CERN, - ALICE - experiment to study the heavy ion interactions at the LHC, - ICARUS - tests of a liquid argon TPC, in preparation for neutrino beam (CERN to Gran Sasso), and to be used for cosmic neutrino detection, - study of charge exchange processes in d-p collisions at Nuclotron in Dubna. A mechanical workshop attached to our

  17. Photoproduction at high energy and high intensity

    CERN Multimedia

    2002-01-01

    The photon beam used for this programme is tagged and provides a large flux up to very high energies (150-200 GeV). It is also hadron-free, since it is obtained by a two-step conversion method. A spectrometer is designed to exploit this beam and to perform a programme of photoproduction with a high level of sensitivity (5-50 events/picobarn).\\\\ \\\\ Priority will be given to the study of processes exhibiting the point-like behaviour of the photon, especially deep inelastic Compton scattering. The spectrometer has two magnets. Charged tracks are measured by MWPC's located only in field-free regions. Three calorimeters provide a large coverage for identifying and measuring electrons and photons. An iron filter downstream identifies muons. Most of the equipment is existing and recuperated from previous experiments.

  18. Hard X-ray spectral investigations of gamma-ray bursts 120521C and 130606A at high-redshift z ˜ 6

    Science.gov (United States)

    Yasuda, T.; Urata, Y.; Enomoto, J.; Tashiro, M. S.

    2017-04-01

    This study presents a temporal and spectral analysis of the prompt emission of two high-redshift gamma-ray bursts (GRBs), 120521C at z ˜ 6 and 130606A at z ˜ 5.91, using data obtained from the Swift-XRT/BAT and the Suzaku-WAM simultaneously. Based on follow-up XRT observations, the longest durations of the prompt emissions were approximately 80 s (120521C) and 360 s (130606A) in the rest-frames of the two GRBs. These objects are thus categorized as long-duration GRBs; however, the durations are short compared with the predicted duration of GRBs originating from first-generation stars. Because of the wide bandpass of the instruments, covering the ranges 15 keV-5 MeV (BAT-WAM) and 0.3 keV-5.0 MeV (XRT-BAT-WAM), we could successfully determine the νFν peak energies E_peak^src in the rest-frame and isotropic-equivalent radiated energies Eiso; E^src_peak = 682^{+845}_{-207} keV and E_iso = (8. 25^{+2.24}_{-1.96}) × 10^{52} erg for 120521C, and E^src_peak = 1209^{+553}_{-304} keV and E_iso = (2.82^{+0.17}_{-0.71}) × 10^{53} erg for 130606A. These obtained characteristic parameters are in accordance with the well-known relationship between E_peak^src and Eiso (Amati relationship). In addition, we examined the relationships between E_peak^src and the 1-s peak luminosity, Lp, and between E_peak^src and the geometrical corrected radiated energy, Eγ, and confirmed the E_peak^src-Lp (Yonetoku) and E_peak^src-Eγ (Ghirlanda) relationships. The results imply that these high-redshift GRBs at z ˜ 6, which are expected to have radiated during the reionization epoch, have properties similar to those of low-redshift GRBs regarding X-ray prompt emission.

  19. THE FERMI-GBM X-RAY BURST MONITOR: THERMONUCLEAR BURSTS FROM 4U 0614+09

    International Nuclear Information System (INIS)

    Linares, M.; Chakrabarty, D.; Connaughton, V.; Bhat, P. N.; Briggs, M. S.; Preece, R.; Jenke, P.; Kouveliotou, C.; Wilson-Hodge, C. A.; Van der Horst, A. J.; Camero-Arranz, A.; Finger, M.; Paciesas, W. S.; Beklen, E.; Von Kienlin, A.

    2012-01-01

    Thermonuclear bursts from slowly accreting neutron stars (NSs) have proven difficult to detect, yet they are potential probes of the thermal properties of the NS interior. During the first year of a systematic all-sky search for X-ray bursts using the Gamma-ray Burst Monitor aboard the Fermi Gamma-ray Space Telescope we have detected 15 thermonuclear bursts from the NS low-mass X-ray binary 4U 0614+09 when it was accreting at nearly 1% of the Eddington limit. We measured an average burst recurrence time of 12 ± 3 days (68% confidence interval) between 2010 March and 2011 March, classified all bursts as normal duration bursts and placed a lower limit on the recurrence time of long/intermediate bursts of 62 days (95% confidence level). We discuss how observations of thermonuclear bursts in the hard X-ray band compare to pointed soft X-ray observations and quantify such bandpass effects on measurements of burst radiated energy and duration. We put our results for 4U 0614+09 in the context of other bursters and briefly discuss the constraints on ignition models. Interestingly, we find that the burst energies in 4U 0614+09 are on average between those of normal duration bursts and those measured in long/intermediate bursts. Such a continuous distribution in burst energy provides a new observational link between normal and long/intermediate bursts. We suggest that the apparent bimodal distribution that defined normal and long/intermediate duration bursts during the last decade could be due to an observational bias toward detecting only the longest and most energetic bursts from slowly accreting NSs.

  20. Extending the search for high-energy muon neutrinos from GRBs with ANTARES

    CERN Multimedia

    2017-01-01

    Gamma-ray bursts (GRBs) are transient sources, potential sites of cosmic-rays acceleration: they are expected to produce high-energy neutrinos in pγ interactions through the decay of charged mesons, thus they constitute promising targets for neutrino telescopes. A search for muon neutrinos from GRBs using 9 years of ANTARES data is here presented, assuming particle acceleration at internal shocks, as expected in the fireball model.

  1. IV. Workshop on High Energy Spin Physics

    International Nuclear Information System (INIS)

    Nurushev, S.

    1992-01-01

    In this proceedings the results on high energy spin physics are summarized. The theory of spin phenomenon and the experimental results at intermediate energy and at high energy spin physics and new technical developments in polarization experiments are presented

  2. Developments in high energy physics

    International Nuclear Information System (INIS)

    Mukhi, Sunil; Roy, Probir

    2009-01-01

    This non-technical review article is aimed at readers with some physics background, including beginning research students. It provides a panoramic view of the main theoretical developments in high energy physics since its inception more than half a century ago, a period in which experiments have spanned an enormous range of energies, theories have been developed leading up to the standard model, and proposals - including the radical paradigm of string theory - have been made to go beyond the standard model. The list of references provided here is not intended to properly credit all original work but rather to supply the reader with a few pointers to the literature, specifically highlighting work done by Indian authors. (author)

  3. Assessing high wind energy penetration

    International Nuclear Information System (INIS)

    Tande, J.O.

    1995-01-01

    In order to convincingly promote installing wind power capacity as a substantial part of the energy supply system, a set of careful analyses must be undertaken. This paper applies a case study concentrated on assessing the cost/benefit of high wind energy penetration. The case study considers expanding the grid connected wind power capacity in Praia, the capital of Cape Verde. The currently installed 1 MW of wind power is estimated to supply close to 10% of the electric energy consumption in 1996. Increasing the wind energy penetration to a higher level is considered viable as the project settings are close to ideal, including a very capable national utility company, Electra, a conventional power supply system based on imported heavy fuel and gas oil, and favourable wind conditions with an estimated annual average of 9.3 m/s at the hub height of the wind turbines. With the applied case study assumptions, simulations with WINSYS over the lifetime of the assessed wind power investment show that investments up to 4.2 MW are economically viable. The economic optimum is found at 2.4 MW reaching an internal rate of return of almost 8% p.a. This 2.4 MW of wind power would, together with the existing wind power, supply over 30% of the electric consumption in 1996. Applying the recommended practices for estimating the cost of wind energy, the life-cycle cost of this 2.4 MW investment is estimated at a 7% discount rate and a 20 year lifetime to 0.26 DKK/kW h. (Author)

  4. Energy Systems High-Pressure Test Laboratory | Energy Systems Integration

    Science.gov (United States)

    Facility | NREL Energy Systems High-Pressure Test Laboratory Energy Systems High-Pressure Test Laboratory In the Energy Systems Integration Facility's High-Pressure Test Laboratory, researchers can safely test high-pressure hydrogen components. Photo of researchers running an experiment with a hydrogen fuel

  5. Observations of gamma-ray bursts

    International Nuclear Information System (INIS)

    Strong, I.B.; Klebesadel, R.W.; Evans, W.D.

    1975-01-01

    Observational data on gamma-ray bursts are reviewed. Information is grouped into temporal properties, energy fluxes and spectral properties, and directions and distributions of the sources in space. (BJG)

  6. Use of water-Cherenkov detectors to detect Gamma Ray Bursts at the Large Aperture GRB Observatory (LAGO)

    International Nuclear Information System (INIS)

    Allard, D.; Allekotte, I.; Alvarez, C.; Asorey, H.; Barros, H.; Bertou, X.; Burgoa, O.; Gomez Berisso, M.; Martinez, O.; Miranda Loza, P.; Murrieta, T.; Perez, G.; Rivera, H.; Rovero, A.; Saavedra, O.; Salazar, H.; Tello, J.C.; Ticona Peralda, R.; Velarde, A.; Villasenor, L.

    2008-01-01

    The Large Aperture GRB Observatory (LAGO) project aims at the detection of high energy photons from Gamma Ray Bursts (GRB) using the single particle technique in ground-based water-Cherenkov detectors (WCD). To reach a reasonable sensitivity, high altitude mountain sites have been selected in Mexico (Sierra Negra, 4550 m a.s.l.), Bolivia (Chacaltaya, 5300 m a.s.l.) and Venezuela (Merida, 4765 m a.s.l.). We report on detector calibration and operation at high altitude, search for bursts in 4 months of preliminary data, as well as search for signal at ground level when satellites report a burst

  7. Use of water-Cherenkov detectors to detect Gamma Ray Bursts at the Large Aperture GRB Observatory (LAGO)

    Energy Technology Data Exchange (ETDEWEB)

    Allard, D. [APC, CNRS et Universite Paris 7 (France); Allekotte, I. [Centro Atomico Bariloche, Instituto Balseiro (Argentina); Alvarez, C. [Facultad de Ciencias Fisico-Matematicas de la BUAP (Mexico); Asorey, H. [Centro Atomico Bariloche, Instituto Balseiro (Argentina); Barros, H. [Laboratorio de Fisica Nuclear, Universidad Simon Bolivar, Caracas (Venezuela, Bolivarian Republic of); Bertou, X. [Centro Atomico Bariloche, Instituto Balseiro (Argentina)], E-mail: bertou@cab.cnea.gov.ar; Burgoa, O. [Instituto de Investigaciones Fisicas, UMSA (Bolivia); Gomez Berisso, M. [Centro Atomico Bariloche, Instituto Balseiro (Argentina); Martinez, O. [Facultad de Ciencias Fisico-Matematicas de la BUAP (Mexico); Miranda Loza, P. [Instituto de Investigaciones Fisicas, UMSA (Bolivia); Murrieta, T.; Perez, G. [Facultad de Ciencias Fisico-Matematicas de la BUAP (Mexico); Rivera, H. [Instituto de Investigaciones Fisicas, UMSA (Bolivia); Rovero, A. [Instituto de Astronomia y Fisica del Espacio (Argentina); Saavedra, O. [Dipartimento di Fisica Generale and INFN, Torino (Italy); Salazar, H. [Facultad de Ciencias Fisico-Matematicas de la BUAP (Mexico); Tello, J.C. [Laboratorio de Fisica Nuclear, Universidad Simon Bolivar, Caracas (Venezuela, Bolivarian Republic of); Ticona Peralda, R.; Velarde, A. [Instituto de Investigaciones Fisicas, UMSA (Bolivia); Villasenor, L. [Facultad de Ciencias Fisico-Matematicas de la BUAP (Mexico); Instituto de Fisica y Matematicas, Universidad de Michoacan (Mexico)

    2008-09-21

    The Large Aperture GRB Observatory (LAGO) project aims at the detection of high energy photons from Gamma Ray Bursts (GRB) using the single particle technique in ground-based water-Cherenkov detectors (WCD). To reach a reasonable sensitivity, high altitude mountain sites have been selected in Mexico (Sierra Negra, 4550 m a.s.l.), Bolivia (Chacaltaya, 5300 m a.s.l.) and Venezuela (Merida, 4765 m a.s.l.). We report on detector calibration and operation at high altitude, search for bursts in 4 months of preliminary data, as well as search for signal at ground level when satellites report a burst.

  8. Duke University high energy physics

    International Nuclear Information System (INIS)

    Fortney, L.R.; Goshaw, A.T.; Walker, W.D.

    1992-07-01

    This Progress Report presents a review of the research done in 1992 by the Duke High Energy Physics Group. This is the first year of a three-year grant which was approved by the Office of High Energy Physics at DOE after an external review of our research program during the summer of 1991. Our research is centered at Fermilab where we are involved with two active experiments, one using the Tevatron collider (CDF, the Collider Detector Facility) and the other using a proton beam in the high intensity laboratory (E771, study of beauty production). In addition to these running experiments we are continuing the analysis of data from experiments E735 (collider search for a quark-gluon plasma), E705 (fixed target study of direct photon and Χ meson production) and E597 (particle production from hadron-nucleus collisions). Finally, this year has seen an expansion of our involvement with the design of the central tracking detector for the Solenoidal Detector Collaboration (SDC) and an increased role in the governance of the collaboration. Descriptions of these research activities are presented in this report

  9. Light Dawns on Dark Gamma-ray Bursts

    Science.gov (United States)

    2010-12-01

    Gamma-ray bursts are among the most energetic events in the Universe, but some appear curiously faint in visible light. The biggest study to date of these so-called dark gamma-ray bursts, using the GROND instrument on the 2.2-metre MPG/ESO telescope at La Silla in Chile, has found that these gigantic explosions don't require exotic explanations. Their faintness is now fully explained by a combination of causes, the most important of which is the presence of dust between the Earth and the explosion. Gamma-ray bursts (GRBs), fleeting events that last from less than a second to several minutes, are detected by orbiting observatories that can pick up their high energy radiation. Thirteen years ago, however, astronomers discovered a longer-lasting stream of less energetic radiation coming from these violent outbursts, which can last for weeks or even years after the initial explosion. Astronomers call this the burst's afterglow. While all gamma-ray bursts [1] have afterglows that give off X-rays, only about half of them were found to give off visible light, with the rest remaining mysteriously dark. Some astronomers suspected that these dark afterglows could be examples of a whole new class of gamma-ray bursts, while others thought that they might all be at very great distances. Previous studies had suggested that obscuring dust between the burst and us might also explain why they were so dim. "Studying afterglows is vital to further our understanding of the objects that become gamma-ray bursts and what they tell us about star formation in the early Universe," says the study's lead author Jochen Greiner from the Max-Planck Institute for Extraterrestrial Physics in Garching bei München, Germany. NASA launched the Swift satellite at the end of 2004. From its orbit above the Earth's atmosphere it can detect gamma-ray bursts and immediately relay their positions to other observatories so that the afterglows could be studied. In the new study, astronomers combined Swift

  10. Potentially lethal effects of astrophysical high energy explosive events

    International Nuclear Information System (INIS)

    Zarauza, Dario; Martin, Osmel; Rolando Cardenas

    2007-01-01

    In this work we compare the biological extinction risks posed by different types of high energy explosive events, if they occur at distances close enough to inhabited planets. These events are several kinds of supernovae and gamma ray bursts. We mainly consider the ozone depletion, leaving other effects, as photon retransmission and muon showers, for future work. In order to estimate the damage on ozonosphere, we use a simple analytical model for ozone depletion. We also mention some hints to look for the signatures of these events on Earth biogeochemical record, and evaluate the possibility of applying these results to the astrobiologically interesting sample of stars gathered by Porto de Mello, del Peloso and Ghezzi. (Author)

  11. Swift Burst Alert Telescope Data Products and Analysis Software

    International Nuclear Information System (INIS)

    Krimm, Hans A.; Barbier, Louis M.; Barthelmy, Scott D.; Cummings, Jay R.; Gehrels, Neil; Parsons, Ann M.; Tueller, Jack; Fenimore, Edward E.; Palmer, David M.; Hullinger, Derek D.; Markwardt, Craig B.

    2004-01-01

    The Burst Alert Telescope (BAT) on the Swift gamma-ray burst mission serves as the GRB trigger for Swift as well as a sensitive imaging telescope for the energy range of 15-150 keV. All BAT data products will be available to the astronomical community along with a complete set of analysis tools. Gamma-ray burst data products include rapid discovery messages delivered immediately via the GRB Coordinates Network, and event-by-event data from which light curves and spectra of the burst are generated. During nominal operations, the instrument provides accumulated survey histograms with 5-minute time sampling and appropriate energy resolution. These survey accumulations are analyzed in a pipeline to detect new sources and derive light curves of known sources. The 5-minute surveys will also be combined to produce the BAT all sky hard X-ray survey. In addition, the instrument accumulates high time resolution light curves of the brightest BAT sources in multiple energy bands, which are merged into a source light curve database on the ground. The BAT science data products and analysis tools will be described in this paper

  12. Weak interactions at high energies

    International Nuclear Information System (INIS)

    Ellis, J.

    1978-08-01

    Review lectures are presented on the phenomenological implications of the modern spontaneously broken gauge theories of the weak and electromagnetic interactions, and some observations are made about which high energy experiments probe what aspects of gauge theories. Basic quantum chromodynamics phenomenology is covered including momentum dependent effective quark distributions, the transverse momentum cutoff, search for gluons as sources of hadron jets, the status and prospects for the spectroscopy of fundamental fermions and how fermions may be used to probe aspects of the weak and electromagnetic gauge theory, studies of intermediate vector bosons, and miscellaneous possibilities suggested by gauge theories from the Higgs bosons to speculations about proton decay. 187 references

  13. High temperature thermoelectric energy conversion

    International Nuclear Information System (INIS)

    Wood, C.

    1986-01-01

    Considerable advances were made in the late '50's and early early '60's in the theory and development of materials for high-temperature thermoelectric energy conversion. This early work culminated in a variety of materials, spanning a range of temperatures, with the product of the figure of merit, Z, and temperature, T, i.e., the dimensionless figure of merit, ZT, of the order of one. This experimental limitation appeared to be universal and led a number of investigators to explore the possibility that a ZT - also represents a theoretical limitation. It was found not to be so

  14. New decoding methods of interleaved burst error-correcting codes

    Science.gov (United States)

    Nakano, Y.; Kasahara, M.; Namekawa, T.

    1983-04-01

    A probabilistic method of single burst error correction, using the syndrome correlation of subcodes which constitute the interleaved code, is presented. This method makes it possible to realize a high capability of burst error correction with less decoding delay. By generalizing this method it is possible to obtain probabilistic method of multiple (m-fold) burst error correction. After estimating the burst error positions using syndrome correlation of subcodes which are interleaved m-fold burst error detecting codes, this second method corrects erasure errors in each subcode and m-fold burst errors. The performance of these two methods is analyzed via computer simulation, and their effectiveness is demonstrated.

  15. High energy beam manufacturing technologies

    International Nuclear Information System (INIS)

    Geskin, E.S.; Leu, M.C.

    1989-01-01

    Technological progress continues to enable us to utilize ever widening ranges of physical and chemical conditions for material processing. The increasing cost of energy, raw materials and environmental control make implementation of advanced technologies inevitable. One of the principal avenues in the development of material processing is the increase of the intensity, accuracy, flexibility and stability of energy flow to the processing site. The use of different forms of energy beams is an effective way to meet these sometimes incompatible requirements. The first important technological applications of high energy beams were welding and flame cutting. Subsequently a number of different kinds of beams have been used to solve different problems of part geometry control and improvement of surface characteristics. Properties and applications of different specific beams were subjects of a number of fundamental studies. It is important now to develop a generic theory of beam based manufacturing. The creation of a theory dealing with general principles of beam generation and beam-material interaction will enhance manufacturing science as well as practice. For example, such a theory will provide a format approach for selection and integration of different kinds of beams for a particular application. And obviously, this theory will enable us to integrate the knowledge bases of different manufacturing technologies. The War of the Worlds by H. G. Wells, as well as a number of more technical, although less exciting, publications demonstrate both the feasibility and effectiveness of the generic approach to the description of beam oriented technology. Without any attempt to compete with Wells, we still hope that this volume will contribute to the creation of the theory of beam oriented manufacturing

  16. High energy polarized electron beams

    International Nuclear Information System (INIS)

    Rossmanith, R.

    1987-01-01

    In nearly all high energy electron storage rings the effect of beam polarization by synchrotron radiation has been measured. The buildup time for polarization in storage rings is of the order of 10 6 to 10 7 revolutions; the spins must remain aligned over this time in order to avoid depolarization. Even extremely small spin deviations per revolution can add up and cause depolarization. The injection and the acceleration of polarized electrons in linacs is much easier. Although some improvements are still necessary, reliable polarized electron sources with sufficiently high intensity and polarization are available. With the linac-type machines SLC at Stanford and CEBAF in Virginia, experiments with polarized electrons will be possible

  17. Duke University High Energy Physics

    International Nuclear Information System (INIS)

    Fortney, L.R.; Goshaw, A.T.; Walker, W.D.

    1993-03-01

    The research program of the Duke High Energy Physics Group is described in this Progress Report and a separate Proposal containing their plans for 1994. These two documents are supplemented by compilations of selected publications, thesis abstracts, and the curriculum vitae of the eleven Ph.D. physicists who are carrying out this research program. This Progress Report contains a review of the research which has been done over the first half (1992 and 1993 to date) of the current three-year DOE grant, plus some earlier research to establish a broader perspective of the research interests. High energy physics research at Duke has three components. The first, Task A, is based upon experiments carried out at Fermilab's Tevatron Collider. The group is finishing the analysis of data from their first collider experiment (E735), a study of inclusive particle production from bar p p collisions at √ bar s = 1.8 TeV. The second component of the research, Task B, deals primarily with heavy flavor physics. The third part of the research program, Task D, deals with preparation for research at the SSC. The authors have been active in the development of tracking detectors for the SSC since 1989, and are now concentrating on the design and construction of straw tube drift chambers for the solenoid detector

  18. Spinoff from high energy physics

    International Nuclear Information System (INIS)

    Hoffmann, Hans

    1994-01-01

    This year the CERN Courier is featuring the spinoff and technological benefits arising from research in fundamental physics. After initial illustrations in applied data processing sectors, this article by Hans Hoffman of CERN examines the rationale and underlying objectives of the 'new awareness' of the market value of basic science. He is the Chairman of a new panel on the subject set up recently by the International Committee for Future Accelerators (ICFA). The other members are: Oscar Barbalat of CERN, Hans Christian Dehne of DESY, Sin-ichi Kurakawa of KEK, Gennady Kulipanov of the Budker Institute (Novosibirsk), Anthony Montgomery, formerly of the SSC, A. H. Walenta of Siegen, Germany, and Zhongqiang Yu of IHEP Beijing. High energy physics - the quest to find and understand the structure of matter - is mainly seen as an essential part of human culture. However this basic science increasingly has to jostle for funding attention with other branches of science. Applied sciences aim for a rapid transformation of investment cash into viable market products. In times of economic difficulties this is attractive to funding agencies and governments, and economic usefulness and technological relevance also become criteria for a basic science like high energy physics.

  19. High energy physics and cosmology

    International Nuclear Information System (INIS)

    Silk, J.I.

    1991-01-01

    This research will focus on the implications of recent theories and experiments in high energy physics of the evolution of the early universe, and on the constraints that cosmological considerations can place on such theories. Several problems are under investigation, including studies of the nature of dark matter and the signature of annihilations in the galactic halo, where the resulting γ-ray fluxes are potentially observable, and in stars, where stellar evolution may be affects. We will develop constraints on the inflationary predictions of scale-free primordial fluctuations in a universe at critical closure density by studying their linear and non-linear evolution after they re-enter the particle horizon, examining the observable imprint of primordial density fluctuations on the cosmic microwave background radiation in both flat and curved cosmological models, and implications for observations of large-scale galaxy clustering and structure formation theories. We will also study spectral distortions in the microwave background radiation that are produced by exotic particle decays in the very early universe. We expect such astrophysical considerations to provide fruitful insights both into high-energy particle physics and into possible cosmological for the early universe

  20. High-energy transients with Fermi/GBM

    International Nuclear Information System (INIS)

    Gruber, David

    2012-01-01

    For most of mankind's history, astronomy was performed on-ground in the optical energy range. It was only when space-based missions, built more than 50 years ago, detected photons with mind-boggling energies that the exploration of the violent Universe really began. These γ-ray photons still provide us with an unprecedented wealth of information for the most energetic processes taking place in the cosmos. Faithful to the olympic slogan ''higher, faster, further'', an increasing armada of γ-ray satellites was built and launched over the last couple of decades with Fermi being the youngest of its kind. In this thesis, I use data from the Gamma-Ray Burst Monitor (GBM) onboard the Fermi satellite. The focus of this work lies on three very different classes of high-energy astrophysical transients: Gamma-Ray Bursts (GRBs), solar flares and Soft Gamma Repeaters (SGRs). In Chapter 2, I present GRB 091024A, a burst of very long duration in γ-rays where optical data could be acquired well during its active phase. The optical light curve shows very intriguing features which I subsequently interpret as the so called ''optical flash'', a fundamental property of the ''fireball'' model. Although predicted by the latter model, only a handful of GRBs show such a behavior, making them interesting transients to study. Furthermore, I present the fundamental temporal and spectral properties of 47 GBM-detected GRBs with known redshifts. As GRBs explode at cosmological distances it is of uttermost importance to study them in their restframe to get a better understanding of their emission mechanisms. I confirm several correlations already found in the past together with an intriguing connection between redshift and the peak energy (E peak ) of GRBs. Although this correlation is heavily influenced by instrumental effects, it is not unexpected from other experimental results, giving it more credibility. Finally, I present the results of the search for untriggered GRBs in GBM data. This

  1. Broadband Study of GRB 091127: A Sub-energetic Burst at Higher Redshift?

    Science.gov (United States)

    Troja, E.; Sakamoto, T.; Guidorzi, C.; Norris, J. P.; Panaitescu, A.; Kobayashi, S.; Omodei, N.; Brown, J. C.; Burrows, D. N.; Evans, P. A.; Gehrels, N.; Marshall, F. E.; Mawson, N.; Melandri, A.; Mundell, C. G.; Oates, S. R.; Pal'shin, V.; Preece, R. D.; Racusin, J. L.; Steele, I. A.; Tanvir, N. R.; Vasileiou, V.; Wilson-Hodge, C.; Yamaoka, K.

    2012-12-01

    GRB 091127 is a bright gamma-ray burst (GRB) detected by Swift at a redshift z = 0.49 and associated with SN 2009nz. We present the broadband analysis of the GRB prompt and afterglow emission and study its high-energy properties in the context of the GRB/SN association. While the high luminosity of the prompt emission and standard afterglow behavior are typical of cosmological long GRBs, its low-energy release (E γ < 3 × 1049 erg), soft spectrum, and unusual spectral lag connect this GRB to the class of sub-energetic bursts. We discuss the suppression of high-energy emission in this burst, and investigate whether this behavior could be connected with the sub-energetic nature of the explosion.

  2. BROADBAND STUDY OF GRB 091127: A SUB-ENERGETIC BURST AT HIGHER REDSHIFT?

    Energy Technology Data Exchange (ETDEWEB)

    Troja, E.; Sakamoto, T.; Brown, J. C.; Gehrels, N.; Marshall, F. E.; Racusin, J. L. [NASA, Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Guidorzi, C. [Physics Department, University of Ferrara, via Saragat 1, I-44122, Ferrara (Italy); Norris, J. P. [Physics Department, Boise State University, 1910 University Drive, Boise, ID 83725 (United States); Panaitescu, A. [Space Science and Applications, MS D466, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Kobayashi, S.; Mawson, N.; Melandri, A.; Mundell, C. G.; Steele, I. A. [Astrophysics Research Institute, Liverpool John Moores University, Twelve Quays House, Egerton Wharf, CH41 1LD Birkenhead (United Kingdom); Omodei, N. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Burrows, D. N. [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States); Evans, P. A. [X-ray and Observational Astronomy Group, Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH (United Kingdom); Oates, S. R. [Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey RH5 6NT (United Kingdom); Pal' shin, V. [Ioffe Physico-Technical Institute, Laboratory for Experimental Astrophysics, 26 Polytekhnicheskaya, St Petersburg 194021 (Russian Federation); Preece, R. D. [Department of Physics, University of Alabama in Huntsville, NSSTC, 320 Sparkman Drive, Huntsville, AL 35805 (United States); and others

    2012-12-10

    GRB 091127 is a bright gamma-ray burst (GRB) detected by Swift at a redshift z = 0.49 and associated with SN 2009nz. We present the broadband analysis of the GRB prompt and afterglow emission and study its high-energy properties in the context of the GRB/SN association. While the high luminosity of the prompt emission and standard afterglow behavior are typical of cosmological long GRBs, its low-energy release (E{sub {gamma}} < 3 Multiplication-Sign 10{sup 49} erg), soft spectrum, and unusual spectral lag connect this GRB to the class of sub-energetic bursts. We discuss the suppression of high-energy emission in this burst, and investigate whether this behavior could be connected with the sub-energetic nature of the explosion.

  3. Transient optical emission from the error box of the gamma-ray burst of 28 February 1997

    DEFF Research Database (Denmark)

    van Paradijs, J.; Groot, P.J.; Galama, T.

    1997-01-01

    For almost a quarter of a century(1), the origin of gamma-ray bursts-brief, energetic bursts of high-energy photons-has remained unknown. The detection of a counterpart at another wavelength has long been thought to be a key to understanding the nature of these bursts (see, for example, ref. 2...... in that galaxy and thus that gamma-ray bursts in general lie at cosmological distance.......), but intensive searches have not revealed such a counterpart. The distribution and properties of the bursts(3) are explained naturally if they lie at cosmological distances (a few Gpc)(4), but there is a countervailing view that they are relatively local objects(5), perhaps distributed in a very large halo...

  4. Experimental High Energy Physics Research

    Energy Technology Data Exchange (ETDEWEB)

    Hohlmann, Marcus [Florida Inst. of Technology, Melbourne, FL (United States). Dept. of Physics and Space Sciences

    2016-01-13

    This final report summarizes activities of the Florida Tech High Energy Physics group supported by DOE under grant #DE-SC0008024 during the period June 2012 – March 2015. We focused on one of the main HEP research thrusts at the Energy Frontier by participating in the CMS experiment. We were exploiting the tremendous physics opportunities at the Large Hadron Collider (LHC) and prepared for physics at its planned extension, the High-Luminosity LHC. The effort comprised a physics component with analysis of data from the first LHC run and contributions to the CMS Phase-2 upgrades in the muon endcap system (EMU) for the High-Luminosity LHC. The emphasis of our hardware work was the development of large-area Gas Electron Multipliers (GEMs) for the CMS forward muon upgrade. We built a production and testing site for such detectors at Florida Tech to complement future chamber production at CERN. The first full-scale CMS GE1/1 chamber prototype ever built outside of CERN was constructed at Florida Tech in summer 2013. We conducted two beam tests with GEM prototype chambers at CERN in 2012 and at FNAL in 2013 and reported the results at conferences and in publications. Principal Investigator Hohlmann served as chair of the collaboration board of the CMS GEM collaboration and as co-coordinator of the GEM detector working group. He edited and authored sections of the detector chapter of the Technical Design Report (TDR) for the GEM muon upgrade, which was approved by the LHCC and the CERN Research Board in 2015. During the course of the TDR approval process, the GEM project was also established as an official subsystem of the muon system by the CMS muon institution board. On the physics side, graduate student Kalakhety performed a Z' search in the dimuon channel with the 2011 and 2012 CMS datasets that utilized 20.6 fb⁻¹ of p-p collisions at √s = 8 TeV. For the dimuon channel alone, the 95% CL lower limits obtained on the mass of a Z' resonance are 2770 Ge

  5. Dynamics of high energy reactions

    International Nuclear Information System (INIS)

    Field, R.D.

    1979-01-01

    During last several years, a new framework to describe strong interaction physics has emerged, i.e. quantum chromodynamics (QCD). It is the simplest field theory which incorporates color-dependent force among quarks. This force is generated by the exchange of colored vector gluons coupled to the quarks in gauge-invariant manner. The theory is closely related to the most successful quantum field theory, QED, and the only but very important difference is the gauge group involved. Although the theory is well defined, precisely what it predicts is not yet clearly known. However, at very high energy or momentum transfer Q, the effective coupling between quarks and gluons decreases toward zero with increasing Q 2 , and the calculation of a process involving high Q 2 is possible by the use of perturbation theory. In this paper, many applications of QCD to the processes involving high momentum transfer are examined. The effective coupling resulting from strong interaction between quarks and gluons, the scale violation in deep inelastic lepton scattering, large mass muon pair production, quark and gluon fragmentation functions, large transverse momentum meson and jet production in hadron-hadron collision, and the search for three-jet events are discussed. (Kako, I.)

  6. High-energy particle diffraction

    International Nuclear Information System (INIS)

    Barone, V.; Predazzi, E.

    2002-01-01

    This monograph gives a comprehensive and up-to-date overview of soft and hard diffraction processes in strong interaction physics. The first part covers the general formalism (the optical analogy, the eikonal picture, high-energy kinematics, S-matrix theory) and soft hadron-hadron scattering (including the Regge theory) in a complete and mature presentation. It can be used as a textbook in particle physics classes. The remainder of the book is devoted to the 'new diffraction': the pomeron in QCD, low-x physics, diffractive deep inelastic scattering and related processes, jet production etc. It presents recent results and experimental findings and their phenomenological interpretations. This part addresses graduate students as well as researchers. (orig.)

  7. Diffraction of high energy electrons

    International Nuclear Information System (INIS)

    Bourret, A.

    1981-10-01

    The diffraction of electrons by a crystal is examined to study its structure. As the electron-substance interaction is strong, it must be treated in a dynamic manner. Using the N waves theory and physical optics the base equations giving the wave at the outlet are deduced for a perfect crystal and their equivalence is shown. The more complex case of an imperfect crystal is then envisaged in these two approaches. In both cases, only the diffraction of high energy electrons ( > 50 KeV) are considered since in the diffraction of slow electrons back scattering cannot be ignored. Taking into account an increasingly greater number of beams, through fast calculations computer techniques, enables images to be simulated in very varied conditions. The general use of the Fast Fourier Transform has given a clear cut practical advantage to the multi-layer method [fr

  8. On Gamma-Ray Bursts

    CERN Document Server

    Ruffini, Remo; Bianco, Carlo Luciano; Caito, Letizia; Chardonnet, Pascal; Cherubini, Christian; Dainotti, Maria Giovanna; Fraschetti, Federico; Geralico, Andrea; Guida, Roberto; Patricelli, Barbara; Rotondo, Michael; Hernandez, Jorge Armando Rueda; Vereshchagin, Gregory; Xue, She-Sheng

    2008-01-01

    (Shortened) We show by example how the uncoding of Gamma-Ray Bursts (GRBs) offers unprecedented possibilities to foster new knowledge in fundamental physics and in astrophysics. After recalling some of the classic work on vacuum polarization in uniform electric fields by Klein, Sauter, Heisenberg, Euler and Schwinger, we summarize some of the efforts to observe these effects in heavy ions and high energy ion collisions. We then turn to the theory of vacuum polarization around a Kerr-Newman black hole, leading to the extraction of the blackholic energy, to the concept of dyadosphere and dyadotorus, and to the creation of an electron-positron-photon plasma. We then present a new theoretical approach encompassing the physics of neutron stars and heavy nuclei. It is shown that configurations of nuclear matter in bulk with global charge neutrality can exist on macroscopic scales and with electric fields close to the critical value near their surfaces. These configurations may represent an initial condition for the...

  9. Solution High-Energy Burst Assembly (SHEBA) results from subprompt critical experiments with uranyl fluoride fuel

    International Nuclear Information System (INIS)

    Cappiello, C.C.; Butterfield, K.B.; Sanchez, R.G.; Bounds, J.A.; Kimpland, R.H.; Damjanovich, R.P.; Jaegers, P.J.

    1997-01-01

    Experiments were performed to measure a variety of parameters for SHEBA: behavior of the facility during transient and steady-state operation; characteristics of the SHEBA fuel; delayed-critical solution height vs solution temperature; initial reactor period and reactivity vs solution height; calibration of power level vs reactor power instrumentation readings; flux profile in SHEBA; radiation levels and neutron spectra outside the assembly for code verification and criticality alarm and dosimetry purposes; and effect on reactivity of voids in the fuel

  10. Possible galactic origin of. gamma. -ray bursts

    Energy Technology Data Exchange (ETDEWEB)

    Manchanda, R K; Ramsden, D [Southampton Univ. (UK). Dept. of Physics

    1977-03-31

    It is stated that extragalactic models for the origin of non-solar ..gamma..-ray bursts include supernova bursts in remote galaxies, and the collapse of the cores of active stars, whilst galactic models are based on flare stars, thermonuclear explosions in neutron stars and the sudden accretion of cometary gas on to neutron stars. The acceptability of any of these models may be tested by the observed size spectrum of the ..gamma..-ray bursts. The extragalactic models predict a power law spectrum with number index -1.5, whilst for the galactic models the number index will be -1. Experimental data on ..gamma..-ray bursts is, however, still meagre, and so far only 44 confirmed events have been recorded by satellite-borne instruments. The number spectrum of the observed ..gamma..-ray bursts indicates that the observed distribution for events with an energy < 10/sup -4/ erg/cm/sup 2/ is flat; this makes the choice of any model completely arbitrary. An analysis of the observed ..gamma..-ray events is here presented that suggests very interesting possibilities for their origin. There appears to be a preferred mean energy for ..gamma..-ray bursts; some 90% of the recorded events show a mean energy between 5 x 10/sup -5/ and 5 x 10/sup -4/ erg/cm/sup 2/, contrary to the predicted characteristics of the number spectrum of various models. A remarkable similarity is found between the distribution of ..gamma..-ray bursts and that of supernova remnants, suggesting a genetic relationship between the two and the galactic origin of the ..gamma..-ray bursts, and the burst source could be identified with completely run down neutron stars, formed during supernova explosions.

  11. A search for spectral lines in gamma-ray bursts using TGRS

    International Nuclear Information System (INIS)

    Kurczynski, P.; Palmer, D.; Seifert, H.; Teegarden, B. J.; Gehrels, N.; Cline, T. L.; Ramaty, R.; Hurley, K.; Madden, N. W.; Pehl, R. H.

    1998-01-01

    We present the results of an ongoing search for narrow spectral lines in gamma-ray burst data. TGRS, the Transient Gamma-Ray Spectrometer aboard the Wind satellite is a high energy-resolution Ge device. Thus it is uniquely situated among the array of space-based, burst sensitive instruments to look for line features in gamma-ray burst spectra. Our search strategy adopts a two tiered approach. An automated 'quick look' scan searches spectra for statistically significant deviations from the continuum. We analyzed all possible time accumulations of spectra as well as individual spectra for each burst. Follow-up analysis of potential line candidates uses model fitting with F-test and χ 2 tests for statistical significance

  12. Magnetar-like X-Ray Bursts Suppress Pulsar Radio Emission

    Energy Technology Data Exchange (ETDEWEB)

    Archibald, R. F.; Lyutikov, M.; Kaspi, V. M.; Tendulkar, S. P. [Department of Physics and McGill Space Institute, McGill University, 3600 University Street, Montreal, QC H3A 2T8 (Canada); Burgay, M.; Possenti, A. [INAF–Osservatorio Astronomico di Cagliari, Via della Scienza 5, I-09047 Selargius (Italy); Esposito, P.; Rea, N. [Anton Pannekoek Institute for Astronomy, University of Amsterdam, Postbus 94249, 1090 GE Amsterdam (Netherlands); Israel, G. [INAF–Osservatorio Astronomico di Roma, via Frascati 33, I-00040 Monteporzio Catone, Roma (Italy); Kerr, M. [Space Science Division, Naval Research Laboratory, Washington, DC 20375-5352 (United States); Sarkissian, J. [CSIRO Astronomy and Space Science, Parkes Observatory, P.O. Box 276, Parkes, NSW 2870 (Australia); Scholz, P., E-mail: archibald@astro.utoronto.ca [National Research Council of Canada, Herzberg Astronomy and Astrophysics, Dominion Radio Astrophysical Observatory, P.O. Box 248, Penticton, BC V2A 6J9 (Canada)

    2017-11-10

    Rotation-powered pulsars and magnetars are two different observational manifestations of neutron stars: rotation-powered pulsars are rapidly spinning objects that are mostly observed as pulsating radio sources, while magnetars, neutron stars with the highest known magnetic fields, often emit short-duration X-ray bursts. Here, we report simultaneous observations of the high-magnetic-field radio pulsar PSR J1119−6127 at X-ray, with XMM-Newton and NuSTAR , and at radio energies with the Parkes radio telescope, during a period of magnetar-like bursts. The rotationally powered radio emission shuts off coincident with the occurrence of multiple X-ray bursts and recovers on a timescale of ∼70 s. These observations of related radio and X-ray phenomena further solidify the connection between radio pulsars and magnetars and suggest that the pair plasma produced in bursts can disrupt the acceleration mechanism of radio-emitting particles.

  13. Observing a Burst with Sunglasses

    Science.gov (United States)

    2003-11-01

    Unique Five-Week VLT Study of the Polarisation of a Gamma-Ray Burst Afterglow "Gamma-ray bursts (GRBs)" are certainly amongst the most dramatic events known in astrophysics. These short flashes of energetic gamma-rays, first detected in the late 1960's by military satellites, last from less than one second to several minutes. GRBs have been found to be situated at extremely large ("cosmological") distances. The energy released in a few seconds during such an event is larger than that of the Sun during its entire lifetime of more than 10,000 million years. The GRBs are indeed the most powerful events since the Big Bang known in the Universe, cf. ESO PR 08/99 and ESO PR 20/00. During the past years circumstantial evidence has mounted that GRBs signal the collapse of extremely massive stars, the so-called hypernovae. This was finally demonstrated some months ago when astronomers, using the FORS instrument on ESO's Very Large Telescope (VLT), documented in unprecedented detail the changes in the spectrum of the light source ("the optical afterglow") of the gamma-ray burst GRB 030329 (cf. ESO PR 16/03). A conclusive and direct link between cosmological gamma-ray bursts and explosions of very massive stars was provided on this occasion. Gamma-Ray Burst GRB 030329 was discovered on March 29, 2003 by NASA's High Energy Transient Explorer spacecraft. Follow-up observations with the UVES spectrograph at the 8.2-m VLT KUEYEN telescope at the Paranal Observatory (Chile) showed the burst to have a redshift of 0.1685 [1]. This corresponds to a distance of about 2,650 million light-years, making GRB 030329 the second-nearest long-duration GRB ever detected. The proximity of GRB 030329 resulted in very bright afterglow emission, permitting the most extensive follow-up observations of any afterglow to date. A team of astronomers [2] led by Jochen Greiner of the Max-Planck-Institut für extraterrestrische Physik (Germany) decided to make use of this unique opportunity to study the

  14. A 20 Mfps high frame-depth CMOS burst-mode imager with low power in-pixel NMOS-only passive amplifier

    Science.gov (United States)

    Wu, L.; San Segundo Bello, D.; Coppejans, P.; Craninckx, J.; Wambacq, P.; Borremans, J.

    2017-02-01

    This paper presents a 20 Mfps 32 × 84 pixels CMOS burst-mode imager featuring high frame depth with a passive in-pixel amplifier. Compared to the CCD alternatives, CMOS burst-mode imagers are attractive for their low power consumption and integration of circuitry such as ADCs. Due to storage capacitor size and its noise limitations, CMOS burst-mode imagers usually suffer from a lower frame depth than CCD implementations. In order to capture fast transitions over a longer time span, an in-pixel CDS technique has been adopted to reduce the required memory cells for each frame by half. Moreover, integrated with in-pixel CDS, an in-pixel NMOS-only passive amplifier alleviates the kTC noise requirements of the memory bank allowing the usage of smaller capacitors. Specifically, a dense 108-cell MOS memory bank (10fF/cell) has been implemented inside a 30μm pitch pixel, with an area of 25 × 30μm2 occupied by the memory bank. There is an improvement of about 4x in terms of frame depth per pixel area by applying in-pixel CDS and amplification. With the amplifier's gain of 3.3, an FD input-referred RMS noise of 1mV is achieved at 20 Mfps operation. While the amplification is done without burning DC current, including the pixel source follower biasing, the full pixel consumes 10μA at 3.3V supply voltage at full speed. The chip has been fabricated in imec's 130nm CMOS CIS technology.

  15. Caging in high energy reactions

    International Nuclear Information System (INIS)

    Ache, H.J.

    1977-01-01

    The concept of caging high energy reactions is considered. It is noted that there is no easy and unambiguous way, short of a complete and very tedious product and mechanistic analysis, which is feasible only for very few systems, to determine the contribution made by caging. It is emphasized that some products resulting from the hot reaction with a certain substrate may be formed via caging while others are not. In research on the mechanism of caging the results of Roots work on the reactions of hot 18 F with the CF 3 CH 3 system seem to provide evidence for caging, with 18 F being the caged moiety, thus proceeding via a radical--radical recombination mechanism. Their work with H 2 S additive also seems to indicate that scavenging via hydrogen abstraction from H 2 S to form does not interfere with the radical--radical recombination consistent with Bunkers molecular approach to explain the cage effects. In other research a series of observations resulting from stereochemical and combined stereochemical density variation techniques seem to favor a caged-complex. It is clear that a more conclusive answer can only be reached by more systematic studies, utilizing the whole range of nuclear reactions such as (n,2n), (n,γ) and E.C. processes in mechanistically well defined systems to elucidate the effect of variations in the recoil energies, by carrying out studies in different solvents or host substances to assess the effect of the physical parameters, such as molecule size and intermolecular interactions on the escape probability or caging efficiencies

  16. High energy physics and cosmology

    International Nuclear Information System (INIS)

    Silk, J.I.; Davis, M.

    1989-01-01

    This research will focus on the implications of recent theories and experiments in high energy physics for the evolution of the early Universe, and on the constraints that cosmological considerations can place on such theories. Several problems are under investigation, including the development of constraints on the inflationary predictions of scale--free primordial fluctuations in a universe at critical closure density by studying their linear and non-linear evolution after they re-enter the particle horizon. We will examine the observable imprint of primordial density fluctuations on the cosmic microwave background radiation curved cosmological models. Most astronomical evidence points to an open universe: one of our goals is to reconcile this conclusion with the particle physics input. We will investigate the response of the matter distribution to a network of cosmic strings produced during an early symmetry-breaking transition, and compute the resulting cosmic microwave background anisotropies. We will simulate the formation of large-scale structures whose dynamics are dominated by weakly interacting particles such as axions, massive neutrinos or photinos in order to model the formation of galaxies, galaxy clusters and superclusters. We will study of the distortions in the microwave background radiation, both spectral and angular, that are produced by ionized gas associated with forming clusters and groups of galaxies. We will also study constraints on exotic cooling mechanisms involving axions and majorons set by stellar evolution and the energy input into low mass stars by cold dark matter annihilation galactic nuclei. We will compute the detailed gamma ray spectrum predicted by various cold dark matter candidates undergoing annihilation in the galactic halo and bulge

  17. [High energy physics and cosmology

    International Nuclear Information System (INIS)

    Silk, J.I.; Davis, M.

    1988-01-01

    This research will focus on the implications of recent theories and experiments in high energy physics for the evolution of the early Universe, and on the constraints that cosmological considerations can place on such theories. Several problems are under investigation, including the development of constraints on the inflationary predictions of scale-free primordial fluctuations in a universe at critical closure density by studying their linear and non-linear evolution after they re-enter the particle horizon. We will examine the observable imprint of primordial density fluctuations on the cosmic microwave background radiation in curved cosmological models. Most astronomical evidence points to an open universe: one of our goals is to reconcile this conclusion with the particle physics input. We will investigate the response of the matter distribution to a network of cosmic strings produced during an early symmetry--breaking transition, and compute the resulting cosmic microwave background anisotropies. We will simulate the formation of large--scale structures whose dynamics are dominated by weakly interacting particles such as axions massive neutrinos or photinos in order to model the formation of galaxies, galaxy clusters and superclusters. We will study the distortions in the microwave background radiation, both spectral and angular, that are produced by ionized gas associated with forming clusters and groups of galaxies. We will also study constraints on exotic cooling mechanisms involving axions and majorons set by stellar evolution and the energy input into low mass stars by cold dark matter annihilation in galactic nuclei. We will compute the detailed gamma ray spectrum predicted by various cold dark matter candidates undergoing annihilation in the galactic halo and bulge

  18. Ultra-High Energy Cosmic Rays and Neutrinos

    International Nuclear Information System (INIS)

    Nagataki, Shigehiro

    2011-01-01

    In this paper, simulation of propagation of UHE-protons from nearby galaxies is presented. We found good parameter sets to explain the arrival distribution of UHECRs reported by AGASA and energy spectrum reported by HiRes. Using a good parameter set, we demonstrated how the distribution of arrival direction of UHECRs will be as a function of event numbers. We showed clearly that 1000-10000 events are necessary to see the clear source distribution. We also showed that effects of interactions and trapping of UHE-Nuclei in a galaxy cluster are very important. Especially, when a UHECR source is a bursting source such as GRB/AGN flare, heavy UHE-Nuclei are trapped for a long time in the galaxy cluster, which changes the spectrum and chemical composition of UHECRs coming from the galaxy cluster. We also showed that such effects can be also important when there have been sources of UHE-Nuclei in Milky Way. Since light nuclei escape from Milky Way in a short timescale, the chemical composition of UHECRs observed at the Earth can be heavy at high-energy range. Finally, we showed how much high-energy neutrinos are produced in GRBs. Since GRB neutrinos do not suffer from magnetic field bending, detection of high-energy neutrinos are very important to identify sources of UHECRs. Especially, for the case of GRBs, high-energy neutrinos arrive at the earth with gamma-rays simultaneously, which is very strong feature to identify the sources of UHECRs.

  19. Quantum Sensing for High Energy Physics

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Zeeshan; et al.

    2018-03-29

    Report of the first workshop to identify approaches and techniques in the domain of quantum sensing that can be utilized by future High Energy Physics applications to further the scientific goals of High Energy Physics.

  20. HIGH ENERGY PHYSICS POTENTIAL AT MUON COLLIDERS

    International Nuclear Information System (INIS)

    PARSA, Z.

    2000-01-01

    In this paper, high energy physics possibilities and future colliders are discussed. The μ + μ - collider and experiments with high intensity muon beams as the stepping phase towards building Higher Energy Muon Colliders (HEMC) are briefly reviewed and encouraged

  1. Lasers and future high energy colliders

    International Nuclear Information System (INIS)

    Parsa, Z.

    1998-02-01

    Future high energy colliders, directions for particle physics and relationship to new technology such as lasers are discussed. Experimental approaches to explore New Physics with emphasis on the utility of high energy colliders are also discussed

  2. A time-dependent search for high-energy neutrinos from bright GRBs with ANTARES

    Directory of Open Access Journals (Sweden)

    Celli Silvia

    2017-01-01

    Full Text Available Astrophysical point-like neutrino sources, like Gamma-Ray Bursts (GRBs, are one of the main targets for neutrino telescopes, since they are among the best candidates for Ultra-High-Energy Cosmic Ray (UHECR acceleration. From the interaction between the accelerated protons and the intense radiation fields of the source jet, charged mesons are produced, which then decay into neutrinos. The methods and the results of a search for high-energy neutrinos in spatial and temporal correlation with the detected gamma-ray emission are presented for four bright GRBs observed between 2008 and 2013: a time-dependent analysis, optimised for each flare of the selected bursts, is performed to predict detailed neutrino spectra. The internal shock scenario of the fireball model is investigated, relying on the neutrino spectra computed through the numerical code NeuCosmA. The analysis is optimized on a per burst basis, through the maximization of the signal discovery probability. Since no events in ANTARES data passed the optimised cuts, 90% C.L. upper limits are derived on the expected neutrino fluences.

  3. THE FIVE YEAR FERMI/GBM MAGNETAR BURST CATALOG

    Energy Technology Data Exchange (ETDEWEB)

    Collazzi, A. C. [SciTec, Inc., 100 Wall Street, Princeton, NJ 08540 (United States); Kouveliotou, C.; Horst, A. J. van der; Younes, G. A. [Department of Physics, The George Washington University, 725 21st Street NW, Washington, DC 20052 (United States); Kaneko, Y.; Göğüş, E. [Sabancı University, Orhanlı-Tuzla, İstanbul 34956 (Turkey); Lin, L. [François Arago Centre, APC, 10 rue Alice Domon et Léonie Duquet, F-75205 Paris (France); Granot, J. [Department of Natural Sciences, The Open University of Israel, 1 University Road, P.O. Box 808, Raanana 43537 (Israel); Finger, M. H. [Universities Space Research Association, NSSTC, 320 Sparkman Drive, Huntsville, AL 35805 (United States); Chaplin, V. L. [School of Medicine, Vanderbilt University, 1161 21st Avenue S, Nashville, TN 37232 (United States); Huppenkothen, D. [Center for Data Science, New York University, 726 Broadway, 7th Floor, New York, NY 10003 (United States); Watts, A. L. [Anton Pannekoek Institute, University of Amsterdam, Postbus 94249, 1090 GE Amsterdam (Netherlands); Kienlin, A. von [Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse 1, D-85748 Garching (Germany); Baring, M. G. [Department of Physics and Astronomy, Rice University, MS-108, P.O. Box 1892, Houston, TX 77251 (United States); Gruber, D. [Planetarium Südtirol, Gummer 5, I-39053 Karneid (Italy); Bhat, P. N. [CSPAR, University of Alabama in Huntsville, 320 Sparkman Drive, Huntsville, AL 35899 (United States); Gibby, M. H., E-mail: acollazzi@scitec.com [Jacobs Technology, Inc., Huntsville, AL (United States); and others

    2015-05-15

    Since launch in 2008, the Fermi Gamma-ray Burst Monitor (GBM) has detected many hundreds of bursts from magnetar sources. While the vast majority of these bursts have been attributed to several known magnetars, there is also a small sample of magnetar-like bursts of unknown origin. Here, we present the Fermi/GBM magnetar catalog, providing the results of the temporal and spectral analyses of 440 magnetar bursts with high temporal and spectral resolution. This catalog covers the first five years of GBM magnetar observations, from 2008 July to 2013 June. We provide durations, spectral parameters for various models, fluences, and peak fluxes for all the bursts, as well as a detailed temporal analysis for SGR J1550–5418 bursts. Finally, we suggest that some of the bursts of unknown origin are associated with the newly discovered magnetar 3XMM J185246.6+0033.7.

  4. Testing Special Relativity at High Energies with Astrophysical Sources

    Science.gov (United States)

    Stecker, F. W.

    2007-01-01

    Since the group of Lorentz boosts is unbounded, there is a question as to whether Lorentz invariance (LI) holds to infinitely short distances. However, special and general relativity may break down at the Planck scale. Various quantum gravity scenarios such as loop quantum gravity, as well as some forms of string theory and extra dimension models may imply Lorentz violation (LV) at ultrahigh energies. The Gamma-Ray Large Area Space Telescope (GLAST), to be launched in mid-December, will measure the spectra of distant extragalactic sources of high energy gamma-rays, particularly active galactic nuclei and gamma-ray bursts. GLAST can look for energy-dependent gamma-ray propagation effects from such sources as a signal of Lorentz invariance violation. These sources may also exhibit the high energy cutoffs predicted to be the result of intergalactic annihilation interactions with low energy photons having a flux level as determined by various astronomical observations. With LV the threshold for such interactions can be significantly raised, changing the predicted absorption turnover in the observed spectrum of the sources. Stecker and Glashow have shown that the existence such absorption features in the spectra of extragalactic sources puts constraints on LV. Such constraints have important implications for some quantum gravity and large extra dimension models. Future spaceborne detectors dedicated to measuring gamma-ray polarization can look for birefringence effects as a possible signal of loop quantum gravity. A very small LV may also result in the modification or elimination of the GZK effect, thus modifying the spectrum of ultrahigh energy cosmic rays. This possibility can be explored with ground-based arrays such as Auger or with a space based detector system such as the proposed OWL satellite mission.

  5. Hadron dynamics at high energies

    International Nuclear Information System (INIS)

    Storrow, J.K.

    1977-01-01

    The nine lectures give a very brief introduction to hadron dynamics at high energies. They concentrate on basic concepts such as Regge poles, duality and geometrical ideas, and simple applications of these ideas to the problem of understanding data. To some extent two body phenomenology is emphasized at the expense of multiparticle final states and when the latter have been considered they have concentrated on inclusive reactions. One lecture discussed data on 2-2 reactions in order to provide the motivation for Regge pole theory, then two lectures are devoted to basic concepts. Then duality is introduced and shown to provide reasonable restrictions on a pole model. A lecture is then devoted to discussing geometrical ideas i.e. the t-dependence of data is looked at from an s-channel point of view. The section on two-body phenomenology is then concluded by discussing applications of the above ideas to two reactions-pion-nucleon scattering and np charge exchange scattering. The remaining three lectures are devoted to multiparticle reactions. Exclusive reactions are considered briefly and then the remainder of the course is concerned with inclusive reactions. The concepts of scaling and limiting fragmentation are discussed and Mueller's generalised optical theorem introduced and then applied in various kinematic limits. (author)

  6. Detection Techniques of Microsecond Gamma-Ray Bursts Using Ground-based Telescopes

    International Nuclear Information System (INIS)

    Krennrich, F.; Le Bohec, S.; Weekes, T. C.

    2000-01-01

    Gamma-ray observations above 200 MeV are conventionally made by satellite-based detectors. The EGRET detector on the Compton Gamma Ray Observatory has provided good sensitivity for the detection of bursts lasting for more than 200 ms. Theoretical predictions of high-energy gamma-ray bursts produced by quantum mechanical decay of primordial black holes (Hawking) suggest the emission of bursts on shorter timescales. The final stage of a primordial black hole results in a burst of gamma rays, peaking around 250 MeV and lasting for 1/10 of a microsecond or longer depending on particle physics. In this work we show that there is an observational window using ground-based imaging Cerenkov detectors to measure gamma-ray burst emission at energies E>200 MeV. This technique, with a sensitivity for bursts lasting nanoseconds to several microseconds, is based on the detection of multiphoton-initiated air showers. (c) (c) 2000. The American Astronomical Society

  7. Search for high energy skimming neutrinos at a surface detector array

    International Nuclear Information System (INIS)

    Vo Van Thuan; Hoang Van Khanh; Pham Ngoc Diep

    2010-01-01

    In the present study we propose a new method for detection of high energy cosmological muon neutrinos by transition radiations at a medium interface. The emerging electro-magnetic radiations induced by earth-skimming heavy charged leptons are able to trigger a few of aligned neighboring local water Cherenkov stations at a surface detector array similar to the Pierre Auger Observatory. The estimation applied to the model of Gamma Ray Burst induced neutrino fluxes and the spherical earth surface shows a competitive rate of muon neutrino events in the energy range below the GZK cut-off. (author)

  8. FERMI OBSERVATIONS OF HIGH-ENERGY GAMMA-RAY EMISSION FROM GRB 080825C

    International Nuclear Information System (INIS)

    Abdo, A. A.; Ackermann, M.; Bechtol, K.; Berenji, B.; Bloom, E. D.; Borgland, A. W.; Bouvier, A.; Asano, K.; Atwood, W. B.; Axelsson, M.; Baldini, L.; Bellazzini, R.; Bregeon, J.; Ballet, J.; Band, D. L.; Barbiellini, G.; Bastieri, D.; Bhat, P. N.; Bissaldi, E.; Bonamente, E.

    2009-01-01

    The Fermi Gamma-ray Space Telescope has opened a new high-energy window in the study of gamma-ray bursts (GRBs). Here we present a thorough analysis of GRB 080825C, which triggered the Fermi Gamma-ray Burst Monitor (GBM), and was the first firm detection of a GRB by the Fermi Large Area Telescope (LAT). We discuss the LAT event selections, background estimation, significance calculations, and localization for Fermi GRBs in general and GRB 080825C in particular. We show the results of temporal and time-resolved spectral analysis of the GBM and LAT data. We also present some theoretical interpretation of GRB 080825C observations as well as some common features observed in other LAT GRBs.

  9. Superconducting magnets in high energy physics

    International Nuclear Information System (INIS)

    Prodell, A.G.

    1978-01-01

    The applications of superconducting magnets in high energy physics in the last ten years have made feasible developments which are vital to high energy research. These developments include high magnetic field, large volume detectors, such as bubble chambers, required for effective resolution of high energy particle trajectories, particle beam transport magnets, and superconducting focusing and bending magnets for the very high energy accelerators and storage rings needed to pursue the study of interactions between elementary particles. The acceptance of superconductivity as a proven technology in high energy physics was reinforced by the recognition that the existing large accelerators using copper-iron magnets had reached practical limits in terms of magnetic field intensity, cost, space, and energy usage, and that large-volume, high-field, copper-iron magnets were not economically feasible. Some of the superconducting magnets and associated systems being used in and being developed for high energy physics are described

  10. High energy physics and grid computing

    International Nuclear Information System (INIS)

    Yu Chuansong

    2004-01-01

    The status of the new generation computing environment of the high energy physics experiments is introduced briefly in this paper. The development of the high energy physics experiments and the new computing requirements by the experiments are presented. The blueprint of the new generation computing environment of the LHC experiments, the history of the Grid computing, the R and D status of the high energy physics grid computing technology, the network bandwidth needed by the high energy physics grid and its development are described. The grid computing research in Chinese high energy physics community is introduced at last. (authors)

  11. X-Ray Spectral Characteristics of Ginga Gamma-Ray Bursts

    International Nuclear Information System (INIS)

    Strohmayer, T.E.; Fenimore, E.E.; Murakami, T.; Yoshida, A.

    1998-01-01

    We have investigated the spectral characteristics of a sample of bright gamma-ray bursts detected with the gamma-ray burst sensors aboard the satellite Ginga. This instrument employed a proportional and scintillation counter to provide sensitivity to photons in the 2 endash 400 keV region and as such provided a unique opportunity to characterize the largely unexplored X-ray properties of gamma-ray bursts. The photon spectra of the Ginga bursts are well described by a low-energy slope, a bend energy, and a high-energy slope. In the energy range where they can be compared, this result is consistent with burst spectral analyses obtained from the BATSE experiment aboard the Compton Gamma-Ray Observatory. However, below 20 keV we find evidence for a positive spectral number index in approximately 40% of our burst sample, with some evidence for a strong rolloff at lower energies in a few events. There is a correlation (Pearson's r = -0.62) between the low-energy slope and the bend energy. We find that the distribution of spectral bend energies extends below 10 keV. There has been some concern in cosmological models of gamma-ray bursts (GRBs) that the bend energy covers only a small dynamic range. Our result extends the observed dynamic range, and, since we observe bend energies down to the limit of our instrument, perhaps observations have not yet limited the range. The Ginga trigger range was virtually the same as that of BATSE, yet we find a different range of fit parameters. One possible explanation might be that GRBs have two break energies, one often in the 50 endash 500 keV range and the other near 5 keV. Both BATSE and Ginga fit with only a single break energy, so BATSE tends to find breaks near the center of its energy range, and we tend to find breaks in our energy range. The observed ratio of energy emitted in the X-rays relative to the gamma rays can be much larger than a few percent and, in fact, is sometimes larger than unity. The average for our 22 bursts

  12. Testing Einstein's Equivalence Principle With Fast Radio Bursts.

    Science.gov (United States)

    Wei, Jun-Jie; Gao, He; Wu, Xue-Feng; Mészáros, Peter

    2015-12-31

    The accuracy of Einstein's equivalence principle (EEP) can be tested with the observed time delays between correlated particles or photons that are emitted from astronomical sources. Assuming as a lower limit that the time delays are caused mainly by the gravitational potential of the Milky Way, we prove that fast radio bursts (FRBs) of cosmological origin can be used to constrain the EEP with high accuracy. Taking FRB 110220 and two possible FRB/gamma-ray burst (GRB) association systems (FRB/GRB 101011A and FRB/GRB 100704A) as examples, we obtain a strict upper limit on the differences of the parametrized post-Newtonian parameter γ values as low as [γ(1.23  GHz)-γ(1.45  GHz)]radio energies, improving by 1 to 2 orders of magnitude the previous results at other energies based on supernova 1987A and GRBs.

  13. High density energy storage capacitor

    International Nuclear Information System (INIS)

    Whitham, K.; Howland, M.M.; Hutzler, J.R.

    1979-01-01

    The Nova laser system will use 130 MJ of capacitive energy storage and have a peak power capability of 250,000 MW. This capacitor bank is a significant portion of the laser cost and requires a large portion of the physical facilities. In order to reduce the cost and volume required by the bank, the Laser Fusion Program funded contracts with three energy storage capacitor producers: Aerovox, G.E., and Maxwell Laboratories, to develop higher energy density, lower cost energy storage capacitors. This paper describes the designs which resulted from the Aerovox development contract, and specifically addresses the design and initial life testing of a 12.5 kJ, 22 kV capacitor with a density of 4.2 J/in 3 and a projected cost in the range of 5 cents per joule

  14. States of high energy density

    International Nuclear Information System (INIS)

    Murray, M.

    1988-02-01

    The transverse energy, E/sub tau/ spectra for O 16 and S 32 incident for various elements at 200 GeVnucleon are shown. The target and projectile dependencies of the data are discussed. The energy density achieved is estimated. For O 16 on Tungsten the multiplicity spectrum is also presented as well as the pseudorapidity spectra as a function of the transverse energy. The multiplicity cross section dσdN as measured in the backward hemisphere (0.9 < /eta/ < 2.9/ is found to be very similar in shape to the transverse energy distribution dσdE/tau/ reflecting the particular geometry of nucleus nucleus nucleus collisions. The dependence on the atomic mass of the target, A/sub tau/ and projectile A/sub p/ is not what one would expect from naive considerations

  15. High energy neutrinos: sources and fluxes

    Energy Technology Data Exchange (ETDEWEB)

    Stanev, Todor [Bartol Research Institute, Department of Physics and Astronomy, University of Delaware, Newark DE 19716 (United States)

    2006-05-15

    We discuss briefly the potential sources of high energy astrophysical neutrinos and show estimates of the neutrino fluxes that they can produce. A special attention is paid to the connection between the highest energy cosmic rays and astrophysical neutrinos.

  16. The emission of Gamma Ray Bursts as a test-bed for modified gravity

    Directory of Open Access Journals (Sweden)

    S. Capozziello

    2015-11-01

    Full Text Available The extreme physical conditions of Gamma Ray Bursts can constitute a useful observational laboratory to test theories of gravity where very high curvature regimes are involved. Here we propose a sort of curvature engine capable, in principle, of explaining the huge energy emission of Gamma Ray Bursts. Specifically, we investigate the emission of radiation by charged particles non-minimally coupled to the gravitational background where higher order curvature invariants are present. The coupling gives rise to an additional force inducing a non-geodesic motion of particles. This fact allows a strong emission of radiation by gravitationally accelerated particles. As we will show with some specific model, the energy emission is of the same order of magnitude of that characterizing the Gamma Ray Burst physics. Alternatively, strong curvature regimes can be considered as a natural mechanism for the generation of highly energetic astrophysical events. Possible applications to cosmology are discussed.

  17. Multiplicities in high energy interactions

    International Nuclear Information System (INIS)

    Derrick, M.

    1984-01-01

    Charged particle multiplicities in hadronic collision have been measured for all energies up to √s = 540 GeV in the center of mass. Similar measurements in e + e - annihilation cover the much smaller range - up to √s = 40 GeV. Data are also available from deep inelastic neutrino scattering up to √s approx. 10 GeV. The experiments measure the mean charged multiplicity , the rapidity density at y = O, and the distributions in prong number. The mean number of photons associated with the events can be used to measure the π 0 and eta 0 multiplicities. Some information is also available on the charged pion, kaon, and nucleon fractions as well as the K 0 and Λ 0 rates and for the higher energy data, the identically equal fraction. We review this data and consider the implications of extrapolations to SSC energies. 13 references

  18. High education and nuclear energy

    International Nuclear Information System (INIS)

    Ghitescu, Petre; Prisecaru, Ilie; Stefanescu, Petre

    1998-01-01

    The Faculty of Energy of the University 'Politecnica' in Bucharest is the only faculty in Romania in the field of nuclear energy education. With an experience of more than 29 years, the Faculty of Energy offers the major 'Nuclear Power Plants', which students graduate after a 5-year education as engineers in the Nuclear Power Plant major. Among the principal objectives of the development and reshape of the Romanian education system was mentioned the upgrading of organizational forms by introducing the transfer credit system, and starting in the fall '97 by accrediting Radioprotection and Nuclear Safety Master education. As a result of co-operation and assistance offered by TEMPUS-SENECA program, the new major is shaped and endowed with a modern curriculum harmonized with UE and IAEA requirements and a modern and performing laboratory. This way the Romanian higher education offers a fully correct and concordant structure with UE countries education. (authors)

  19. Bursting neurons and ultrasound avoidance in crickets

    Directory of Open Access Journals (Sweden)

    Gary eMarsat

    2012-07-01

    Full Text Available Decision making in invertebrates often relies on simple neural circuits composed of only a few identified neurons. The relative simplicity of these circuits makes it possible to identify the key computation and neural properties underlying decisions. In this review, we summarize recent research on the neural basis of ultrasound avoidance in crickets, a response that allows escape from echolocating bats. The key neural property shaping behavioral output is high-frequency bursting of an identified interneuron, AN2, which carries information about ultrasound stimuli from receptor neurons to the brain. AN2's spike train consists of clusters of spikes –bursts– that may be interspersed with isolated, non-burst spikes. AN2 firing is necessary and sufficient to trigger avoidance steering but only high-rate firing, such as occurs in bursts, evokes this response. AN2 bursts are therefore at the core of the computation involved in deciding whether or not to steer away from ultrasound. Bursts in AN2 are triggered by synaptic input from nearly synchronous bursts in ultrasound receptors. Thus the population response at the very first stage of sensory processing –the auditory receptor- already differentiates the features of the stimulus that will trigger a behavioral response from those that will not. Adaptation, both intrinsic to AN2 and within ultrasound receptors, scales the burst-generating features according to the stimulus statistics, thus filtering out background noise and ensuring that bursts occur selectively in response to salient peaks in ultrasound intensity. Furthermore AN2’s sensitivity to ultrasound varies adaptively with predation pressure, through both developmental and evolutionary mechanisms. We discuss how this key relationship between bursting and the triggering of avoidance behavior is also observed in other invertebrate systems such as the avoidance of looming visual stimuli in locusts or heat avoidance in beetles.

  20. High energy particle accelerators as radiation Sources

    Energy Technology Data Exchange (ETDEWEB)

    Abdelaziz, M E [National Center for Nuclear Safety and Radiation Vontrol, Atomic Energy Authority, Cairo (Egypt)

    1997-12-31

    Small accelerators in the energy range of few million electron volts are usually used as radiation sources for various applications, like radiotherapy, food irradiation, radiation sterilization and in other industrial applications. High energy accelerators with energies reaching billions of electron volts also find wide field of applications as radiation sources. Synchrotrons with high energy range have unique features as radiation sources. This review presents a synopsis of cyclic accelerators with description of phase stability principle of high energy accelerators with emphasis on synchrotrons. Properties of synchrotron radiation are given together with their applications in basic and applied research. 13 figs.,1 tab.

  1. The Transient High Energy Sky and Early Universe Surveyor (THESEUS)

    Science.gov (United States)

    Amati, Lorenzo; O'Brien, Paul T.; Götz, Diego

    2016-07-01

    The Transient High Energy Sky and Early Universe Surveyor (THESEUS) is a mission concept under development by a large international collaboration aimed at exploiting gamma-ray bursts for investigating the early Universe. The main scientific objectives of THESEUS include: investigating the star formation rate and metallicity evolution of the ISM and IGM up to redshift 9-10, detecting the first generation (pop III) of stars, studying the sources and physics of re-ionization, detecting the faint end of galaxies luminosity function. These goals will be achieved through a unique combination of instruments allowing GRB detection and arcmin localization over a broad FOV (more than 1sr) and an energy band extending from several MeVs down to 0.3 keV with unprecedented sensitivity, as well as on-board prompt (few minutes) follow-up with a 0.6m class IR telescope with both imaging and spectroscopic capabilities. Such instrumentation will also allow THESEUS to unveil and study the population of soft and sub-energetic GRBs, and, more in general, to perform monitoring and survey of the X-ray sky with unprecedented sensitivity.

  2. Moderate energy ions for high energy density physics experiments

    International Nuclear Information System (INIS)

    Grisham, L.R.

    2004-01-01

    This paper gives the results of a preliminary exploration of whether moderate energy ions (≅0.3-3 MeV/amu) could be useful as modest-cost drivers for high energy density physics experiments. It is found that if the target thickness is chosen so that the ion beam enters and then leaves the target in the vicinity of the peak of the dE/dX (stopping power) curve, high uniformity of energy deposition may be achievable while also maximizing the amount of energy per beam particle deposited within the target

  3. Gamma-Ray Bursts from Neutron Star Kicks

    Science.gov (United States)

    Huang, Y. F.; Dai, Z. G.; Lu, T.; Cheng, K. S.; Wu, X. F.

    2003-09-01

    The idea that gamma-ray bursts might be a phenomenon associated with neutron star kicks was first proposed by Dar & Plaga. Here we study this mechanism in more detail and point out that the neutron star should be a high-speed one (with proper motion larger than ~1000 km s-1). It is shown that the model agrees well with observations in many aspects, such as the energetics, the event rate, the collimation, the bimodal distribution of durations, the narrowly clustered intrinsic energy, and the association of gamma-ray bursts with supernovae and star-forming regions. We also discuss the implications of this model on the neutron star kick mechanism and suggest that the high kick speed was probably acquired as the result of the electromagnetic rocket effect of a millisecond magnetar with an off-centered magnetic dipole.

  4. Harvard University High Energy Physics progress report

    International Nuclear Information System (INIS)

    1992-01-01

    The principal goals of this work are to carry out forefront programs in high energy physics research and to provide first rate educational opportunities for students. The experimental program supported through HEPL is carried out at the major accelerator centers in the world and addresses some of the most important questions in high energy physics. The program is based at Harvard's High Energy Physics Laboratory, which has offices, computing facilities, and engineering support, and both electronics and machine shops

  5. Split School of High Energy Physics 2015

    CERN Document Server

    2015-01-01

    Split School of High Energy Physics 2015 (SSHEP 2015) was held at the Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture (FESB), University of Split, from September 14 to September 18, 2015. SSHEP 2015 aimed at master and PhD students who were interested in topics pertaining to High Energy Physics. SSHEP 2015 is the sixth edition of the High Energy Physics School. Previous five editions were held at the Department of Physics, University of Sarajevo, Bosnia and Herzegovina.

  6. High-energy electron diffraction and microscopy

    CERN Document Server

    Peng, L M; Whelan, M J

    2011-01-01

    This book provides a comprehensive introduction to high energy electron diffraction and elastic and inelastic scattering of high energy electrons, with particular emphasis on applications to modern electron microscopy. Starting from a survey of fundamental phenomena, the authors introduce the most important concepts underlying modern understanding of high energy electron diffraction. Dynamical diffraction in transmission (THEED) and reflection (RHEED) geometries is treated using ageneral matrix theory, where computer programs and worked examples are provided to illustrate the concepts and to f

  7. Particle accelerators and lasers high energy sources

    International Nuclear Information System (INIS)

    Watteau, J.P.

    1985-04-01

    Particle accelerators and lasers are to-day precious devices for physicist and engineer. Their performance and scope do not stop growing. Producing thin beams of high energy particles or photons, they are able to be very high energy sources which interact strongly with matter. Numerous applications use them: research, industry, communication, medicine, agroalimentary, defence, and soon. In this note, their operation principles are described and some examples of their use as high energy sources are given [fr

  8. Renewable energy at high altitudes

    International Nuclear Information System (INIS)

    Beltramo, R.; Cuzzolin, B.

    2000-01-01

    Improving environmental performance by paying greater attention to the environment factor is becoming the prime objective of many companies and organizations in general. But not theirs alone. Even the tourism sector is making a number of efforts in this direction. This is the case, for example, of the Regina Margherita Refuge located on Point Gnifetti on the Monte Rosa massif, where a research project called Crest was conducted. This was a study on the feasibility of meeting the refuge's energy sources, that is, by using a photovoltaic or hybrid (wind-based and photovoltaic) energy production system. A plant thus able to exploit the landscape and meteorological characteristics typical of a mountain refuge, saving money and reducing the pollution load [it

  9. High-energy cosmic rays

    CERN Document Server

    Cronin, James Watson

    1996-01-01

    Recently two cosmic rays with energy in excess of 2 1020 eV have been recorded. These are some 108 times more energetic than the protons produced by accelerators on earth. There is no credible understanding of the mechanism of acceleration by known a Because of the short mean free path in the cosmic background radiation they must come from nearby distances on a cosmological scale (< 50 Mpc). Their magnetic rigidity suggests that they should point to their source. Lectures will cover the present available data on the highest energy cosmic rays, their detection, possible acceleration mechanisms, their propagation in the galaxy and in extra galactic space and design of new detectors where simulations of air show ers play an important role.

  10. Predicting rock bursts in mines

    Science.gov (United States)

    Spall, H.

    1979-01-01

    In terms of lives lost, rock bursts in underground mines can be as hazardous as earthquakes on the surface. So it is not surprising that fo the last 40 years the U.S Bureau of Mines has been using seismic methods for detecting areas in underground mines where there is a high differential stress which could lead to structural instability of the rock mass being excavated.

  11. Correlation of high energy muons with primary composition in extensive air shower

    Science.gov (United States)

    Chou, C.; Higashi, S.; Hiraoka, N.; Ozaki, S.; Sato, T.; Suwada, T.; Takahasi, T.; Umeda, H.

    1985-01-01

    An experimental investigation of high energy muons above 200 GeV in extensive air showers has been made for studying high energy interaction and primary composition of cosmic rays of energies in the range 10 to the 14th power approx. 10 to the 15th power eV. The muon energies are estimated from the burst sizes initiated by the muons in the rock, which are measured by four layers of proportional counters, each of area 5 x 2.6 sq m, placed at 30 m.w.e. deep, Funasaka tunnel vertically below the air shower array. These results are compared with Monte Carlo simulations based on the scaling model and the fireball model for two primary compositions, all proton and mixed.

  12. High Energy Astrophysics Science Archive Research Center

    Data.gov (United States)

    National Aeronautics and Space Administration — The High Energy Astrophysics Science Archive Research Center (HEASARC) is the primary archive for NASA missions dealing with extremely energetic phenomena, from...

  13. High Energy Solid State Laser Research Facility

    Data.gov (United States)

    Federal Laboratory Consortium — A suite of laboratories with advanced spectroscopic and laser equipment, this facility develops materials and techniques for advanced solid state high energy lasers....

  14. High energy physics and cloud computing

    International Nuclear Information System (INIS)

    Cheng Yaodong; Liu Baoxu; Sun Gongxing; Chen Gang

    2011-01-01

    High Energy Physics (HEP) has been a strong promoter of computing technology, for example WWW (World Wide Web) and the grid computing. In the new era of cloud computing, HEP has still a strong demand, and major international high energy physics laboratories have launched a number of projects to research on cloud computing technologies and applications. It describes the current developments in cloud computing and its applications in high energy physics. Some ongoing projects in the institutes of high energy physics, Chinese Academy of Sciences, including cloud storage, virtual computing clusters, and BESⅢ elastic cloud, are also described briefly in the paper. (authors)

  15. High Average Power, High Energy Short Pulse Fiber Laser System

    Energy Technology Data Exchange (ETDEWEB)

    Messerly, M J

    2007-11-13

    Recently continuous wave fiber laser systems with output powers in excess of 500W with good beam quality have been demonstrated [1]. High energy, ultrafast, chirped pulsed fiber laser systems have achieved record output energies of 1mJ [2]. However, these high-energy systems have not been scaled beyond a few watts of average output power. Fiber laser systems are attractive for many applications because they offer the promise of high efficiency, compact, robust systems that are turn key. Applications such as cutting, drilling and materials processing, front end systems for high energy pulsed lasers (such as petawatts) and laser based sources of high spatial coherence, high flux x-rays all require high energy short pulses and two of the three of these applications also require high average power. The challenge in creating a high energy chirped pulse fiber laser system is to find a way to scale the output energy while avoiding nonlinear effects and maintaining good beam quality in the amplifier fiber. To this end, our 3-year LDRD program sought to demonstrate a high energy, high average power fiber laser system. This work included exploring designs of large mode area optical fiber amplifiers for high energy systems as well as understanding the issues associated chirped pulse amplification in optical fiber amplifier systems.

  16. URBox : High tech energy and informal housing

    NARCIS (Netherlands)

    Cuperus, Y.J.; Smets, D.

    2011-01-01

    This paper reports on the URBox concept encompassing the high tech end of solar energy and informal low cost and affordable housing. It aims to contribute to solving the global energy crisis by building solar energy settlements in deserts where land is affordable and sunshine in abundance. First the

  17. Responding to high energy prices: energy management services

    International Nuclear Information System (INIS)

    Raynolds, M.

    2001-01-01

    Rapid growth in the number and sophistication of energy management companies has been observed in the wake of rising energy prices. These companies offer energy-efficiency consulting services to utilities, government and industry with the promise of improved cost efficiency, marketplace competitiveness and environmental commitments. The environmental benefits result from the reduction in emissions and pollutants associated with power production and natural gas used for space heating. In general, the stock in trade of these energy management companies is the energy audit involving evaluation of existing equipment in buildings and facilities and the resulting recommendations to install energy-efficient equipment such as lighting retrofits, boiler replacement, chiller replacement, variable speed drives, high-efficiency motors, improved insulation and weather proofing, water heaters and piping. The North American market for energy management services was estimated in 1997 at $208 billion (rising to $350 billion by 2004). Current market penetration is less than two per cent

  18. Bursting and critical layer frequencies in minimal turbulent dynamics and connections to exact coherent states

    Science.gov (United States)

    Park, Jae Sung; Shekar, Ashwin; Graham, Michael D.

    2018-01-01

    The dynamics of the turbulent near-wall region is known to be dominated by coherent structures. These near-wall coherent structures are observed to burst in a very intermittent fashion, exporting turbulent kinetic energy to the rest of the flow. In addition, they are closely related to invariant solutions known as exact coherent states (ECS), some of which display nonlinear critical layer dynamics (motions that are highly localized around the surface on which the streamwise velocity matches the wave speed of ECS). The present work aims to investigate temporal coherence in minimal channel flow relevant to turbulent bursting and critical layer dynamics and its connection to the instability of ECS. It is seen that the minimal channel turbulence displays frequencies very close to those displayed by an ECS family recently identified in the channel flow geometry. The frequencies of these ECS are determined by critical layer structures and thus might be described as "critical layer frequencies." While the bursting frequency is predominant near the wall, the ECS frequencies (critical layer frequencies) become predominant over the bursting frequency at larger distances from the wall, and increasingly so as Reynolds number increases. Turbulent bursts are classified into strong and relatively weak classes with respect to an intermittent approach to a lower branch ECS. This temporally intermittent approach is closely related to an intermittent low drag event, called hibernating turbulence, found in minimal and large domains. The relationship between the strong burst and the instability of the lower branch ECS is further discussed in state space. The state-space dynamics of strong bursts is very similar to that of the unstable manifolds of the lower branch ECS. In particular, strong bursting processes are always preceded by hibernation events. This precursor dynamics to strong turbulence may aid in development of more effective control schemes by a way of anticipating dynamics

  19. Swiftly searching the sky: the first three years of the Swift gamma-ray burst explorer

    International Nuclear Information System (INIS)

    Nousek, John; Varela, Karen; Quijandria, Fernando

    2009-01-01

    The Swift Gamma-Ray Burst Explorer has revolutionized the study of these remarkable high-energy explosions. We summarize the technical developments which lead to the creation of the Swift mission, and outline the highlights of the first three years, and the prospects ahead.

  20. High-Energy Neutrino Interactions

    CERN Multimedia

    2002-01-01

    This experiment studies neutrino interactions in iron at the highest available energies using the narrow-band neutrino beam N3 and the wide-band neutrino beam N1. The basis of the detector is a massive target-calorimeter in which the energy deposited by a neutrino (or antineutrino) is measured by electronic techniques and the momentum of outgoing muons is determined by magnetic deflection. The detector is constructed in the form of a 20 m long iron-cored toroidal magnet, composed of modules of length 70~cm and 90~cm, and of 3.75~m diameter. Drift chambers placed in between each module measure the trajectory of muons from the neutrino interactions. The modules are of three types. The first ten modules are constructed of 2.5~cm iron plates with 20~scintillator planes inserted between the plates. The next five modules are constructed of 5~cm plates with 15~planes of scintillator and the last six modules are constructed of 15~cm plates with 5~planes of scintillators. The total mass of the detector is @=~1400 tons...

  1. HOW ELSE CAN WE DETECT FAST RADIO BURSTS?

    Energy Technology Data Exchange (ETDEWEB)

    Lyutikov, Maxim [Department of Physics and Astronomy, Purdue University, 525 Northwestern Avenue, West Lafayette, IN 47907-2036 (United States); Lorimer, Duncan R., E-mail: lyutikov@purdue.edu [Department of Physics and Astronomy, West Virginia University, Morgantown, WV 26506-6315 (United States)

    2016-06-20

    We discuss possible electromagnetic signals accompanying Fast Radio Bursts (FRBs) that are expected in the scenario where FRBs originate in neutron star magnetospheres. For models involving Crab-like giant pulses, no appreciable contemporaneous emission is expected at other wavelengths. However, magnetar giant flares, driven by the reconfiguration of the magnetosphere, can produce both contemporaneous bursts at other wavelengths as well as afterglow-like emission. We conclude that the best chances are: (i) prompt short GRB-like emission, (ii) a contemporaneous optical flash that can reach naked eye peak luminosity (but only for a few milliseconds), and (iii) a high-energy afterglow emission. Case (i) could be tested by coordinated radio and high-energy experiments. Case (ii) could be seen in a coordinated radio-optical surveys, e.g., by the Palomar Transient Factory in a 60 s frame as a transient object of m = 15–20 mag with an expected optical detection rate of about 0.1 hr{sup −1}, an order of magnitude higher than in radio. Shallow, but large-area sky surveys such as ASAS-SN and EVRYSCOPE could also detect prompt optical flashes from the more powerful Lorimer-burst clones. The best constraints on the optical to radio power for this kind of emission could be provided by future observations with facilities like Large Synoptic Survey Telescope. Case (iii) might be seen in relatively rare cases that the relativistically ejected magnetic blob is moving along the line of sight.

  2. HOW ELSE CAN WE DETECT FAST RADIO BURSTS?

    International Nuclear Information System (INIS)

    Lyutikov, Maxim; Lorimer, Duncan R.

    2016-01-01

    We discuss possible electromagnetic signals accompanying Fast Radio Bursts (FRBs) that are expected in the scenario where FRBs originate in neutron star magnetospheres. For models involving Crab-like giant pulses, no appreciable contemporaneous emission is expected at other wavelengths. However, magnetar giant flares, driven by the reconfiguration of the magnetosphere, can produce both contemporaneous bursts at other wavelengths as well as afterglow-like emission. We conclude that the best chances are: (i) prompt short GRB-like emission, (ii) a contemporaneous optical flash that can reach naked eye peak luminosity (but only for a few milliseconds), and (iii) a high-energy afterglow emission. Case (i) could be tested by coordinated radio and high-energy experiments. Case (ii) could be seen in a coordinated radio-optical surveys, e.g., by the Palomar Transient Factory in a 60 s frame as a transient object of m = 15–20 mag with an expected optical detection rate of about 0.1 hr"−"1, an order of magnitude higher than in radio. Shallow, but large-area sky surveys such as ASAS-SN and EVRYSCOPE could also detect prompt optical flashes from the more powerful Lorimer-burst clones. The best constraints on the optical to radio power for this kind of emission could be provided by future observations with facilities like Large Synoptic Survey Telescope. Case (iii) might be seen in relatively rare cases that the relativistically ejected magnetic blob is moving along the line of sight.

  3. A Strong Limit on the Very-high-energy Emission from GRB 150323A

    Science.gov (United States)

    Abeysekara, A. U.; Archer, A.; Benbow, W.; Bird, R.; Brose, R.; Buchovecky, M.; Bugaev, V.; Connolly, M. P.; Cui, W.; Errando, M.; Falcone, A.; Feng, Q.; Finley, J. P.; Flinders, A.; Fortson, L.; Furniss, A.; Gillanders, G. H.; Hütten, M.; Hanna, D.; Hervet, O.; Holder, J.; Hughes, G.; Humensky, T. B.; Johnson, C. A.; Kaaret, P.; Kar, P.; Kelley-Hoskins, N.; Kertzman, M.; Kieda, D.; Krause, M.; Krennrich, F.; Lang, M. J.; Lin, T. T. Y.; Maier, G.; McArthur, S.; Moriarty, P.; Mukherjee, R.; O’Brien, S.; Ong, R. A.; Park, N.; Perkins, J. S.; Petrashyk, A.; Pohl, M.; Popkow, A.; Pueschel, E.; Quinn, J.; Ragan, K.; Reynolds, P. T.; Richards, G. T.; Roache, E.; Rulten, C.; Sadeh, I.; Santander, M.; Sembroski, G. H.; Shahinyan, K.; Tyler, J.; Wakely, S. P.; Weiner, O. M.; Weinstein, A.; Wells, R. M.; Wilcox, P.; Wilhelm, A.; Williams, D. A.; Zitzer, B.; VERITAS Collaboration; Vurm, Indrek; Beloborodov, Andrei

    2018-04-01

    On 2015 March 23, the Very Energetic Radiation Imaging Telescope Array System (VERITAS) responded to a Swift-Burst Alert Telescope (BAT) detection of a gamma-ray burst, with observations beginning 270 s after the onset of BAT emission, and only 135 s after the main BAT emission peak. No statistically significant signal is detected above 140 GeV. The VERITAS upper limit on the fluence in a 40-minute integration corresponds to about 1% of the prompt fluence. Our limit is particularly significant because the very-high-energy (VHE) observation started only ∼2 minutes after the prompt emission peaked, and Fermi-Large Area Telescope observations of numerous other bursts have revealed that the high-energy emission is typically delayed relative to the prompt radiation and lasts significantly longer. Also, the proximity of GRB 150323A (z = 0.593) limits the attenuation by the extragalactic background light to ∼50% at 100–200 GeV. We conclude that GRB 150323A had an intrinsically very weak high-energy afterglow, or that the GeV spectrum had a turnover below ∼100 GeV. If the GRB exploded into the stellar wind of a massive progenitor, the VHE non-detection constrains the wind density parameter to be A ≳ 3 × 1011 g cm‑1, consistent with a standard Wolf–Rayet progenitor. Alternatively, the VHE emission from the blast wave would be weak in a very tenuous medium such as the interstellar medium, which therefore cannot be ruled out as the environment of GRB 150323A.

  4. Interferometry of high energy nuclear collisions

    International Nuclear Information System (INIS)

    Padula, S.S.

    1990-01-01

    The interferometry is used for determining large space time dimensions of the Quark Gluon Plasma formed in high energy nuclear collisions or in high multiplicity fluctuations in p-barp collisions. (M.C.K.)

  5. High energy physics in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Month, M.

    1985-10-16

    The US program in high energy physics from 1985 to 1995 is reviewed. The program depends primarily upon work at the national accelerator centers, but includes a modest but diversified nonaccelerator program. Involvement of universities is described. International cooperation in high energy physics is discussed, including the European, Japanese, USSR, and the People's Republic of China's programs. Finally, new facilities needed by the US high energy physics program are discussed, with particular emphasis given to a Superconducting Super Collider for achieving ever higher energies in the 20 TeV range. (LEW)

  6. High energy physics in the United States

    International Nuclear Information System (INIS)

    Month, M.

    1985-01-01

    The US program in high energy physics from 1985 to 1995 is reviewed. The program depends primarily upon work at the national accelerator centers, but includes a modest but diversified nonaccelerator program. Involvement of universities is described. International cooperation in high energy physics is discussed, including the European, Japanese, USSR, and the People's Republic of China's programs. Finally, new facilities needed by the US high energy physics program are discussed, with particular emphasis given to a Superconducting Super Collider for achieving ever higher energies in the 20 TeV range

  7. A unified treatment of high energy interactions

    International Nuclear Information System (INIS)

    Drescher, H.J.; Werner, K.; Ostapchenko, S.; Centre National de la Recherche Scientifique, 44 - Nantes

    1999-01-01

    It is well known that high energy interactions as different as electron-positron annihilation, deep inelastic lepton-nucleon scattering, proton-proton interactions, and nucleus-nucleus collisions have many features in common. Based upon this observation, a model for all these interactions is constructed which relies on the fundamental hypothesis that the behavior of high energy interactions is universal. (author)

  8. CAMAC high energy physics electronics hardware

    International Nuclear Information System (INIS)

    Kolpakov, I.F.

    1977-01-01

    CAMAC hardware for high energy physics large spectrometers and control systems is reviewed as is the development of CAMAC modules at the High Energy Laboratory, JINR (Dubna). The total number of crates used at the Laboratory is 179. The number of CAMAC modules of 120 different types exceeds 1700. The principles of organization and the structure of developed CAMAC systems are described. (author)

  9. Expectations for ultra-high energy interactions

    International Nuclear Information System (INIS)

    Feynman, R.P.

    1978-01-01

    Strong interactions at ultra-high energies are discussed with emphasis on the hadrons produced in high energy collisions. Evidence is considered that quantum chromodynamics might be the right theory, and also some estimates are given of quantum chromodynamics asymptotic-freedom phenomena, the work under discussion being very preliminary. 6 references

  10. New aspects of high energy density plasma

    International Nuclear Information System (INIS)

    Hotta, Eiki

    2005-10-01

    The papers presented at the symposium on 'New aspects of high energy density plasma' held at National Institute for Fusion Science are collected in this proceedings. The papers reflect the present status and recent progress in the experiments and theoretical works on high energy density plasma produced by pulsed power technology. The 13 of the presented papers are indexed individually. (J.P.N.)

  11. NICER Eyes on Bursting Stars

    Science.gov (United States)

    Kohler, Susanna

    2018-03-01

    What happens to a neutron stars accretion disk when its surface briefly explodes? A new instrument recently deployed at the International Space Station (ISS) is now watching bursts from neutron stars and reporting back.Deploying a New X-Ray MissionLaunch of NICER aboard a Falcon 9 rocket in June 2017. [NASA/Tony Gray]In early June of 2017, a SpaceX Dragon capsule on a Falcon 9 rocket launched on a resupply mission to the ISS. The pressurized interior of the Dragon contained the usual manifest of crew supplies, spacewalk equipment, and vehicle hardware. But the unpressurized trunk of the capsule held something a little different: the Neutron star Interior Composition Explorer (NICER).In the two weeks following launch, NICER was extracted from the SpaceX Dragon capsule and installed on the ISS. And by the end of the month, the instrument was already collecting its first data set: observations of a bright X-ray burst from Aql X-1, a neutron star accreting matter from a low-mass binary companion.Impact of BurstsNICERs goal is to provide a new view of neutron-star physics at X-ray energies of 0.212 keV a window that allows us to explore bursts of energy that neutron stars sometimes emit from their surfaces.Artists impression of an X-ray binary, in which a compact object accretes material from a companion star. [ESA/NASA/Felix Mirabel]In X-ray burster systems, hydrogen- and helium-rich material from a low-mass companion star piles up in an accretion disk around the neutron star. This material slowly funnels onto the neutron stars surface, forming a layer that gravitationally compresses and eventually becomes so dense and hot that runaway nuclear fusion ignites.Within seconds, the layer of material is burned up, producing a burst of emission from the neutron star that outshines even the inner regions of the hot accretion disk. Then more material funnels onto the neutron star and the process begins again.Though we have a good picture of the physics that causes these bursts

  12. High energy physics at UCR

    Energy Technology Data Exchange (ETDEWEB)

    Kernan, A.; Shen, B.C.

    1997-07-01

    The hadron collider group is studying proton-antiproton interactions at the world`s highest collision energy 2 TeV. Data-taking with the D0 detector is in progress at Fermilab and the authors have begun the search for the top quark. S. Wimpenny is coordinating the effort to detect t{bar t} decaying to two leptons, the most readily identifiable channel. At UC Riverside design and testing for a silicon tracker for the D0 upgrade is in progress; a parallel development for the SDC detector at SSC is also underway. The major group effort of the lepton group has been devoted to the OPAL experiment at LEP. They will continue to focus on data-taking to improve the quality and quantity of their data sample. A large number of papers have been published based on approximately 500,000 events taken so far. The authors will concentrate on physics analysis which provides stringent tests of the Standard Model. The authors are continuing participation in the RD5 experiment at the SPS to study muon triggering and tracking. The results of this experiment will provide critical input for the design of the Compact Muon Solenoid experiment being proposed for the LHC. The theory group has been working on problems concerning the possible vilation of e-{mu}-{tau} universality, effective Lagrangians, neutrino physics, as well as quark and lepton mass matrices.

  13. High energy physics at UCR

    International Nuclear Information System (INIS)

    Kernan, A.; Shen, B.C.

    1997-01-01

    The hadron collider group is studying proton-antiproton interactions at the world's highest collision energy 2 TeV. Data-taking with the D0 detector is in progress at Fermilab and the authors have begun the search for the top quark. S. Wimpenny is coordinating the effort to detect t bar t decaying to two leptons, the most readily identifiable channel. At UC Riverside design and testing for a silicon tracker for the D0 upgrade is in progress; a parallel development for the SDC detector at SSC is also underway. The major group effort of the lepton group has been devoted to the OPAL experiment at LEP. They will continue to focus on data-taking to improve the quality and quantity of their data sample. A large number of papers have been published based on approximately 500,000 events taken so far. The authors will concentrate on physics analysis which provides stringent tests of the Standard Model. The authors are continuing participation in the RD5 experiment at the SPS to study muon triggering and tracking. The results of this experiment will provide critical input for the design of the Compact Muon Solenoid experiment being proposed for the LHC. The theory group has been working on problems concerning the possible vilation of e-μ-τ universality, effective Lagrangians, neutrino physics, as well as quark and lepton mass matrices

  14. High energy density lithium batteries

    CERN Document Server

    Aifantis, Katerina E; Kumar, R Vasant

    2010-01-01

    Cell phones, portable computers and other electronic devices crucially depend on reliable, compact yet powerful batteries. Therefore, intensive research is devoted to improving performance and reducing failure rates. Rechargeable lithium-ion batteries promise significant advancement and high application potential for hybrid vehicles, biomedical devices, and everyday appliances. This monograph provides special focus on the methods and approaches for enhancing the performance of next-generation batteries through the use of nanotechnology. Deeper understanding of the mechanisms and strategies is

  15. Remarks on High Energy Evolution

    OpenAIRE

    Kovner, Alex; Lublinsky, Michael

    2005-01-01

    We make several remarks on the B-JIMWLK hierarchy. First, we present a simple and instructive derivation of this equation by considering an arbitrary projectile wave function with small number of valence gluons. We also generalize the equation by including corrections which incorporate effects of high density in the projectile wave function. Second, we systematically derive the dipole model approximation to the hierarchy. We show that in the dipole approximation the hierarchy has a simplifyin...

  16. Ultra high energy gamma-ray astronomy

    International Nuclear Information System (INIS)

    Wdowczyk, J.

    1986-01-01

    The experimental data on ultra high energy γ-rays are reviewed and a comparison of the properties of photon and proton initiated shower is made. The consequences of the existence of the strong ultra high energy γ-ray sources for other observations is analysed and possible mechanisms for the production of ultra high energy γ-rays in the sources are discussed. It is demonstrated that if the γ-rays are produced via cosmic ray interactions the sources have to produce very high fluxes of cosmic ray particles. In fact it is possible that a small number of such sources can supply the whole Galactic cosmic ray flux

  17. X-ray echoes from gamma-ray bursts

    International Nuclear Information System (INIS)

    Dermer, C.D.; Hurley, K.C.; Hartmann, D.H.

    1991-01-01

    The identification of an echo of reflected radiation in time histories of gamma-ray burst spectra can provide important information about the existence of binary companions or accretion disks in gamma-ray burst systems. Because of the nature of Compton scattering, the spectrum of the echo will be attenuated at gamma-ray energies compared with the spectrum of the primary burst emission. The expected temporal and spectral signatures of the echo and a search for such echoes are described, and implications for gamma-ray burst models are discussed. 35 refs

  18. Observation of cosmic gamma ray burst by Hinotori

    International Nuclear Information System (INIS)

    Okudaira, Kiyoaki; Yoshimori, Masato; Hirashima, Yo; Kondo, Ichiro.

    1982-01-01

    The solar gamma ray detecor (SGR) on Hinotori has no collimator, and the collimator of a hard X-ray monitor is not effective for gamma ray with energy more than 100 KeV. Accordingly, the detection system can detect cosmic gamma ray burst, and two bursts were observed. The first burst was detected on February 28, 1981, and the source of the burst was in the direction of 81 degree from Venus. The time profile and the spectrum were observed. In July 21, 1981, the second burst was detected. The time profile obtained with the SGR was compared with those of PVO (Pioneer Venus Orbiter) and LASL-ISEE. The time difference among the data of time profiles indicated that the source of the burst was not the sun. The spectrum was also measured. (Kato, T.)

  19. Gamma-Ray Bursts: 4th Huntsville Symposium. Proceedings

    International Nuclear Information System (INIS)

    Meegan, C.A.; Preece, R.D.; Koshut, T.M.

    1998-01-01

    These proceedings represent papers presented at the Fourth Huntsville Gamma-Ray Bursts Symposium held in September, 1997 in Huntsville, Alabama, USA. This conference occurred at a crucial time in the history of the gamma-ray burst research. In early 1997, 30 years after the detection of the first gamma-ray burst by the Vela satellites, counterparts to bursts were finally detected at optical and radio wavelengths. The symposium attracted about 200 scientists from 16 countries. Some of the topics discussed include gamma-ray burst spectra, x-ray observations, optical observations, radio observations, host galaxies, shocks and afterglows and models of gamma-ray bursts. There were 183 papers presented, out of these, 16 have been abstracted for the Energy Science and Technology database

  20. Bubble bursting at an interface

    Science.gov (United States)

    Kulkarni, Varun; Sajjad, Kumayl; Anand, Sushant; Fezzaa, Kamel

    2017-11-01

    Bubble bursting is crucial to understanding the life span of bubbles at an interface and more importantly the nature of interaction between the bulk liquid and the outside environment from the point of view of chemical and biological material transport. The dynamics of the bubble as it rises from inside the liquid bulk to its disappearance on the interface after bursting is an intriguing process, many aspects of which are still being explored. In our study, we make detailed high speed imaging measurements to examine carefully the hole initiation and growth in bursting bubbles that unearth some interesting features of the process. Previous analyses available in literature are revisited based on our novel experimental visualizations. Using a combination of experiments and theory we investigate the role of various forces during the rupturing process. This work aims to further our current knowledge of bubble dynamics at an interface with an aim of predicting better the bubble evolution from its growth to its eventual integration with the liquid bulk.

  1. High- and middle-energy geothermics

    International Nuclear Information System (INIS)

    Anon.

    1995-01-01

    High and middle energy geothermal resources correspond to temperature intervals of 220-350 C and 90-180 C, respectively, and are both exploited for electricity production. Exploitation techniques and applications of high and of middle energy geothermics are different. High energy geothermics is encountered in active volcanic and tectonic zones, such as the circum-Pacific fire-belt, the lesser Antilles, the peri-Mediterranean Alpine chain or the African rift zone. The geothermal steam is directly expanded in a turbine protected against gas and minerals corrosion. About 350 high energy plants are distributed in more than 20 different countries and represent 6000 M We. The cost of high energy installed geothermal kWh ranges from 0.20 to 0.50 French Francs. Middle energy geothermics is encountered in sedimentary basins (between 2000 and 4000 m of depth), in localized fractured zones or at lower depth in the high energy geothermal fields. Heat exchangers with organic fluid Rankine cycle technology is used to produce electricity. Unit power of middle energy plants generally ranges from few hundreds of k W to few MW and correspond to a worldwide installed power of about 400 M We. The annual progression of geothermal installed power is estimated to 4 to 8 % in the next years and concerns principally the circum-Pacific countries. In France, geothermal resources are mainly localized in overseas departments. (J.S.). 3 photos

  2. High energy hadron spin-flip amplitude

    International Nuclear Information System (INIS)

    Selyugin, O.V.

    2016-01-01

    The high-energy part of the hadron spin-flip amplitude is examined in the framework of the new high-energy general structure (HEGS) model of the elastic hadron scattering at high energies. The different forms of the hadron spin-flip amplitude are compared in the impact parameter representation. It is shown that the existing experimental data of the proton-proton and proton-antiproton elastic scattering at high energy in the region of the diffraction minimum and at large momentum transfer give support in the presence of the energy-independent part of the hadron spin-flip amplitude with the momentum dependence proposed in the works by Galynskii-Kuraev. [ru

  3. Individual Dosimetry for High Energy Radiation Fields

    International Nuclear Information System (INIS)

    Spurny, F.

    1999-01-01

    The exposure of individuals on board aircraft increased interest in individual dosimetry in high energy radiation fields. These fields, both in the case of cosmic rays as primary radiation and at high energy particle accelerators are complex, with a large diversity of particle types, their energies, and linear energy transfer (LET). Several already existing individual dosemeters have been tested in such fields. For the component with high LET (mostly neutrons) etched track detectors were tested with and without fissile radiators, nuclear emulsions, bubble detectors for both types available and an albedo dosemeter. Individual dosimetry for the low LET component has been performed with thermoluminescent detectors (TLDs), photographic film dosemeters and two types of electronic individual dosemeters. It was found that individual dosimetry for the low LET component was satisfactory with the dosemeters tested. As far as the high LET component is concerned, there are problems with both the sensitivity and the energy response. (author)

  4. Study on cosmic gamma bursts in the ''KONUS'' experiment

    International Nuclear Information System (INIS)

    Mazets, E.P.; Golenetskij, S.V.; Il'inskij, V.N.; Panov, V.N.; Aptekar', R.L.; Gur'yan, Yu.A.; Sokolov, I.A.; Sokolova, Z.Ya.; Kharitonova, T.V.

    1979-01-01

    Made are the investigations of cosmic gamma bursts with the help of the ''Konus'' apparatus, positioned on the ''Venera 11'' and ''Venera 12'' automatic interplanetary stations. 37 gamma bursts have been recorded in the energy range from 50 to 150 keV during the observation period from September to December 1978. Time profiles of bursts on 4, 9 and 24.11.1978 are presented. For the most events the time of burst increase and decrease constitute parts and units of seconds. Differential energy spectra are measured for all recorded bursts. In many cases the spectrum shape is similar to the grade one with the 1.5-2.3 index. In a graphical form built up are the integral distributions of gamma bursts appearence frequency in dependence on their intensity and maximum capacity in the burst peak. Galaxy coordinates of the 17-teen bursts, for which a simple localization is possible, are put on the celestial sphere map. The type of the integral distributions and the source distribution about the celestial sphere show that the gamma burst sources are whithin the Galaxy

  5. Sources of type III solar microwave bursts

    Directory of Open Access Journals (Sweden)

    Zhdanov D.A.

    2016-06-01

    Full Text Available Microwave fine structures allow us to study plasma evolution in an energy release region. The Siberian Solar Radio Telescope (SSRT is a unique instrument designed to examine fine structures at 5.7 GHz. A complex analysis of data from RATAN-600, 4–8 GHz spectropolarimeter, and SSRT, simultaneously with EUV data, made it possible to localize sources of III type microwave bursts in August 10, 2011 event within the entire frequency band of burst occurrence, as well as to determine the most probable region of primary energy release. To localize sources of III type bursts from RATAN-600 data, an original method for data processing has been worked out. At 5.7 GHz, the source of bursts was determined along two coordinates, whereas at 4.5, 4.7, 4.9, 5.1, 5.3, 5.5, and 6.0 GHz, their locations were identified along one coordinate. The size of the burst source at 5.1 GHz was found to be maximum as compared to those at other frequencies.

  6. Intercomparison of high energy neutron personnel dosimeters

    International Nuclear Information System (INIS)

    McDonald, J.C.; Akabani, G.; Loesch, R.M.

    1993-03-01

    An intercomparison of high-energy neutron personnel dosimeters was performed to evaluate the uniformity of the response characteristics of typical neutron dosimeters presently in use at US Department of Energy (DOE) accelerator facilities. It was necessary to perform an intercomparison because there are no national or international standards for high-energy neutron dosimetry. The testing that is presently under way for the Department of Energy Laboratory Accreditation Program (DOELAP) is limited to the use of neutron sources that range in energy from about 1 keV to 2 MeV. Therefore, the high-energy neutron dosimeters presently in use at DOE accelerator facilities are not being tested effectively. This intercomparison employed neutrons produced by the 9 Be(p,n) 9 B interaction at the University of Washington cyclotron, using 50-MeV protons. The resulting neutron energy spectrum extended to a maximum of approximately 50-MeV, with a mean energy of about 20-MeV. Intercomparison results for currently used dosimeters, including Nuclear Type A (NTA) film, thermoluminescent dosimeter (TLD)-albedo, and track-etch dosimeters (TEDs), indicated a wide variation in response to identical doses of high-energy neutrons. Results of this study will be discussed along with a description of plans for future work

  7. Practical neutron dosimetry at high energies

    International Nuclear Information System (INIS)

    McCaslin, J.B.; Thomas, R.H.

    1980-10-01

    Dosimetry at high energy particle accelerators is discussed with emphasis on physical measurements which define the radiation environment and provide an immutable basis for the derivation of any quantities subsequently required for risk evaluation. Results of inter-laboratory dosimetric comparisons are reviewed and it is concluded that a well-supported systematic program is needed which would make possible detailed evaluations and inter-comparisons of instruments and techniques in well characterized high energy radiation fields. High-energy dosimetry is so coupled with radiation transport that it is clear their study should proceed concurrently

  8. Computing in high-energy physics

    International Nuclear Information System (INIS)

    Mount, Richard P.

    2016-01-01

    I present a very personalized journey through more than three decades of computing for experimental high-energy physics, pointing out the enduring lessons that I learned. This is followed by a vision of how the computing environment will evolve in the coming ten years and the technical challenges that this will bring. I then address the scale and cost of high-energy physics software and examine the many current and future challenges, particularly those of management, funding and software-lifecycle management. Lastly, I describe recent developments aimed at improving the overall coherence of high-energy physics software

  9. Computing in high-energy physics

    Science.gov (United States)

    Mount, Richard P.

    2016-04-01

    I present a very personalized journey through more than three decades of computing for experimental high-energy physics, pointing out the enduring lessons that I learned. This is followed by a vision of how the computing environment will evolve in the coming ten years and the technical challenges that this will bring. I then address the scale and cost of high-energy physics software and examine the many current and future challenges, particularly those of management, funding and software-lifecycle management. Finally, I describe recent developments aimed at improving the overall coherence of high-energy physics software.

  10. CERN and the high energy frontier

    Directory of Open Access Journals (Sweden)

    Tsesmelis Emmanuel

    2014-04-01

    Full Text Available This paper presents the particle physics programme at CERN at the high-energy frontier. Starting from the key open questions in particle physics and the large-scale science facilities existing at CERN, concentrating on the Large Hadron Collider(LHC, this paper goes on to present future possibilities for global projects in high energy physics. The paper presents options for future colliders, all being within the framework of the recently updated European Strategy for Particle Physics, and all of which have a unique value to add to experimental particle physics. The paper concludes by outlining key messages for the way forward for high-energy physics research.

  11. On the Future High Energy Colliders

    Energy Technology Data Exchange (ETDEWEB)

    Shiltsev, Vladimir [Fermilab

    2015-09-28

    High energy particle colliders have been in the forefront of particle physics for more than three decades. At present the near term US, European and international strategies of the particle physics community are centered on full exploitation of the physics potential of the Large Hadron Collider (LHC) through its high-luminosity upgrade (HL-LHC). A number of the next generation collider facilities have been proposed and are currently under consideration for the medium and far-future of accelerator-based high energy physics. In this paper we offer a uniform approach to evaluation of various accelerators based on the feasibility of their energy reach, performance potential and cost range.

  12. Biological effects of high-energy radiation

    International Nuclear Information System (INIS)

    Curtis, S.B.

    1976-01-01

    The biological effects of high-energy radiation are reviewed, with emphasis on the effects of the hadronic component. Proton and helium ion effects are similar to those of the more conventional and sparsely ionizing x- and γ-radiation. Heavy-ions are known to be more biologically effective, but the long term hazard from accumulated damage has yet to be assessed. Some evidence of widely varying but dramatically increased effectiveness of very high-energy (approximately 70 GeV) hadron beams is reviewed. Finally, the importance of the neutron component in many situations around high-energy accelerators is pointed out

  13. New accelerators in high-energy physics

    International Nuclear Information System (INIS)

    Blewett, J.P.

    1982-01-01

    First, I should like to mention a few new ideas that have appeared during the last few years in the accelerator field. A couple are of importance in the design of injectors, usually linear accelerators, for high-energy machines. Then I shall review some of the somewhat sensational accelerator projects, now in operation, under construction or just being proposed. Finally, I propose to mention a few applications of high-energy accelerators in fields other than high-energy physics. I realize that this is a digression from my title but I hope that you will find it interesting

  14. The Average Temporal and Spectral Evolution of Gamma-Ray Bursts

    International Nuclear Information System (INIS)

    Fenimore, E.E.

    1999-01-01

    We have averaged bright BATSE bursts to uncover the average overall temporal and spectral evolution of gamma-ray bursts (GRBs). We align the temporal structure of each burst by setting its duration to a standard duration, which we call T left-angleDurright-angle . The observed average open-quotes aligned T left-angleDurright-angle close quotes profile for 32 bright bursts with intermediate durations (16 - 40 s) has a sharp rise (within the first 20% of T left-angleDurright-angle ) and then a linear decay. Exponentials and power laws do not fit this decay. In particular, the power law seen in the X-ray afterglow (∝T -1.4 ) is not observed during the bursts, implying that the X-ray afterglow is not just an extension of the average temporal evolution seen during the gamma-ray phase. The average burst spectrum has a low-energy slope of -1.03, a high-energy slope of -3.31, and a peak in the νF ν distribution at 390 keV. We determine the average spectral evolution. Remarkably, it is also a linear function, with the peak of the νF ν distribution given by ∼680-600(T/T left-angleDurright-angle ) keV. Since both the temporal profile and the peak energy are linear functions, on average, the peak energy is linearly proportional to the intensity. This behavior is inconsistent with the external shock model. The observed temporal and spectral evolution is also inconsistent with that expected from variations in just a Lorentz factor. Previously, trends have been reported for GRB evolution, but our results are quantitative relationships that models should attempt to explain. copyright copyright 1999. The American Astronomical Society

  15. High energy physics. Ultimate structure of matter and energy

    International Nuclear Information System (INIS)

    1979-04-01

    Some of the principle discoveries and insights and their development up to today are sketched. It is shown how one layer after another was discovered by penetrating farther into the structure of matter. Covered are the mounting energy scale, discoveries at high energy frontier, the families of quarks and leptons, the four forces of nature, some achievements of the past few years, particle accelerators and experimental apparatus. A glossary of terms is included

  16. The Drift Burst Hypothesis

    DEFF Research Database (Denmark)

    Christensen, Kim; Oomen, Roel; Renò, Roberto

    are an expected and regular occurrence in financial markets that can arise through established mechanisms such as feedback trading. At a theoretical level, we show how to build drift bursts into the continuous-time Itô semi-martingale model in such a way that the fundamental arbitrage-free property is preserved......, currencies and commodities. We find that the majority of identified drift bursts are accompanied by strong price reversals and these can therefore be regarded as “flash crashes” that span brief periods of severe market disruption without any material longer term price impacts....

  17. Dynamic encoding of natural luminance sequences by LGN bursts.

    Directory of Open Access Journals (Sweden)

    Nicholas A Lesica

    2006-07-01

    Full Text Available In the lateral geniculate nucleus (LGN of the thalamus, visual stimulation produces two distinct types of responses known as tonic and burst. Due to the dynamics of the T-type Ca(2+ channels involved in burst generation, the type of response evoked by a particular stimulus depends on the resting membrane potential, which is controlled by a network of modulatory connections from other brain areas. In this study, we use simulated responses to natural scene movies to describe how modulatory and stimulus-driven changes in LGN membrane potential interact to determine the luminance sequences that trigger burst responses. We find that at low resting potentials, when the T channels are de-inactivated and bursts are relatively frequent, an excitatory stimulus transient alone is sufficient to evoke a burst. However, to evoke a burst at high resting potentials, when the T channels are inactivated and bursts are relatively rare, prolonged inhibitory stimulation followed by an excitatory transient is required. We also observe evidence of these effects in vivo, where analysis of experimental recordings demonstrates that the luminance sequences that trigger bursts can vary dramatically with the overall burst percentage of the response. To characterize the functional consequences of the effects of resting potential on burst generation, we simulate LGN responses to different luminance sequences at a range of resting potentials with and without a mechanism for generating bursts. Using analysis based on signal detection theory, we show that bursts enhance detection of specific luminance sequences, ranging from the onset of excitatory sequences at low resting potentials to the offset of inhibitory sequences at high resting potentials. These results suggest a dynamic role for burst responses during visual processing that may change according to behavioral state.

  18. High to ultra-high power electrical energy storage.

    Science.gov (United States)

    Sherrill, Stefanie A; Banerjee, Parag; Rubloff, Gary W; Lee, Sang Bok

    2011-12-14

    High power electrical energy storage systems are becoming critical devices for advanced energy storage technology. This is true in part due to their high rate capabilities and moderate energy densities which allow them to capture power efficiently from evanescent, renewable energy sources. High power systems include both electrochemical capacitors and electrostatic capacitors. These devices have fast charging and discharging rates, supplying energy within seconds or less. Recent research has focused on increasing power and energy density of the devices using advanced materials and novel architectural design. An increase in understanding of structure-property relationships in nanomaterials and interfaces and the ability to control nanostructures precisely has led to an immense improvement in the performance characteristics of these devices. In this review, we discuss the recent advances for both electrochemical and electrostatic capacitors as high power electrical energy storage systems, and propose directions and challenges for the future. We asses the opportunities in nanostructure-based high power electrical energy storage devices and include electrochemical and electrostatic capacitors for their potential to open the door to a new regime of power energy.

  19. High energy physics and nuclear structure

    International Nuclear Information System (INIS)

    Measday, D.F.; Thomas, A.W.

    1980-01-01

    These proceedings contain the papers presented at the named conference. These concern eletromagnetic interactions, weak interactions, strong interactions at intermediate energy, pion reactions, proton reactions, strong interactions at high energy, as well as new facilities and applications. See hints under the relevant topics. (HSI)

  20. Ultra high-energy cosmic ray composition

    International Nuclear Information System (INIS)

    Longley, N.P.

    1993-01-01

    The Soudan 2 surface-underground cosmic ray experiment can simultaneously measure surface shower size, underground muon multiplicity, and underground muon separation for ultra high energy cosmic ray showers. These measurements are sensitive to the primary composition. Analysis for energies from 10 1 to 10 4 TeV favors a light flux consisting of predominantly H and He nuclei

  1. Pi-nucleon phenomenology at high energies

    International Nuclear Information System (INIS)

    Kogitz, S.

    1973-01-01

    A brief introduction to the phenomenology of strong interactions at high energy is presented. This includes discussion of the topics including absorption, finite energy sum rules, and duality. The application of these ideas to two-particle inelastic reactions is examined. (author)

  2. Experiments on very high energy heavy ions

    International Nuclear Information System (INIS)

    Willis, W.J.

    1981-01-01

    In this paper I describe experimental techniques which could be used to investigate central collision of very high energy heavy ions. For my purposes, the energy range is defined by the number of pions produced, Nsub(π) >> 100, and consequently Nsub(π) >> Nsub(nucleon). In this regime we may expect that new phenomena will appear. (orig.)

  3. Energy confinement of high-density tokamaks

    NARCIS (Netherlands)

    Schüller, F.C.; Schram, D.C.; Coppi, B.; Sadowski, W.

    1977-01-01

    Neoclassical ion heat conduction is the major energy loss mechanism in the center of an ohmically heated high-d. tokamak discharge (n>3 * 1020 m-3). This fixes the mutual dependence of plasma quantities on the axis and leads to scaling laws for the poloidal b and energy confinement time, given the

  4. Geometrical scaling in high energy hadron collisions

    International Nuclear Information System (INIS)

    Kundrat, V.; Lokajicek, M.V.

    1984-06-01

    The concept of geometrical scaling for high energy elastic hadron scattering is analyzed and its basic equations are solved in a consistent way. It is shown that they are applicable to a rather small interval of momentum transfers, e.g. maximally for |t| 2 for pp scattering at the ISR energies. (author)

  5. BURST FLUENCE DISTRIBUTIONS OF SOFT GAMMA REPEATERS 1806–20 AND 1900+14 IN THE ROSSI X-RAY TIMING EXPLORER PCA ERA

    International Nuclear Information System (INIS)

    Prieskorn, Zachary; Kaaret, Philip

    2012-01-01

    We study the fluence distributions of over 3040 bursts from SGR 1806–20 and over 1963 bursts from SGR 1900+14 using the complete set of observations available from the Rossi X-Ray Timing Explorer/Proportional Counter Array through 2011 March. Cumulative event distributions are presented for both sources and are fitted with single and broken power laws as well as an exponential cutoff. The distributions are best fitted by a broken power law with exponential cutoff; however the statistical significance of the cutoff is not high and the upper portion of the broken power law can be explained as the expected number of false bursts due to random noise fluctuations. Event distributions are also examined in high and low burst rate regimes and power-law indices are found to be consistent, independent of the burst rate. The contribution function of the event fluence is calculated. This distribution shows that the energy released in the soft gamma repeater (SGR) bursts is dominated by the most powerful events for both sources. The power-law nature of these distributions combined with the dominant energy dissipation of the system occurring in the large, less frequent bursts is indicative of a self-organized critical system, as suggested by Goğus et al. in 1999.

  6. Low energy current accumulator for high-energy proton rings

    International Nuclear Information System (INIS)

    Month, M.

    1977-01-01

    Building current in high-energy p-p colliding beam machines is most appropriately done in a low-energy (small circumference) current accumulator. Three significant factors favor such a procedure: First, large rings tend to be susceptible to unstable longitudinal density oscillations. These can be avoided by pumping up the beam in the accumulator. When the current stack is injected into the storage ring, potentially harmful instability is essentially neutralized. Second, high-field magnets characteristic of future high energy proton rings are designed with superconducting coils within the iron magnetic shield. This means coil construction and placement errors propagate rapidly within the beam aperture. An intermediate ''stacking ring'' allows the minimum use of the superconducting ring aperture. Finally, the coils are vulnerable to radiation heating and possible magnet quenching. By minimizing beam manipulaion in the superconducting environment and using only the central portion of the beam aperture, coil vulnerability can be put at a minimum

  7. Cosmic gamma-ray burst

    International Nuclear Information System (INIS)

    Yamagami, Takamasa

    1985-01-01

    Ballon experiments for searching gamma-ray burst were carried out by employing rotating-cross modulation collimators. From a very long observation of total 315 hours during 1975 to 1979, three gamma-ray intensity anomalies were observed which were speculated as a gamma-ray burst. As for the first gamma-ray intensity anomaly observed in 1975, the burst source could be located precisely but the source, heavenly body, could not be specified. Gamma-ray burst source estimation was made by analyzing distribution of burst source in the celestial sphere, burst size distribution, and burst peak. Using the above-mentioned data together with previously published ones, apparent inconsistency was found between the observed results and the adopted theory that the source was in the Galaxy, and this inconsistency was found due to the different time profiles of the burst observed with instruments of different efficiency. It was concluded by these analysis results that employment of logN - logP (relation between burst frequency and burst count) was better than that of logN - logS (burst size) in the examination of gamma-ray burst because the former was less uncertain than the latter. Analyzing the author's observed gamma-ray burst data and the related published data, it was clarified that the burst distribution was almost P -312 for the burst peak value larger than 10 -6 erg/cm 2 .sec. The author could indicate that the calculated celestial distribution of burst source was consistent with the observed results by the derivation using the logN - logP relationship and that the burst larger than 10 -6 erg/cm 2 .sec happens about one thousand times a year, about ten times of the previous value. (Takagi, S.)

  8. High-energy transients with Fermi/GBM

    Energy Technology Data Exchange (ETDEWEB)

    Gruber, David

    2012-10-09

    For most of mankind's history, astronomy was performed on-ground in the optical energy range. It was only when space-based missions, built more than 50 years ago, detected photons with mind-boggling energies that the exploration of the violent Universe really began. These {gamma}-ray photons still provide us with an unprecedented wealth of information for the most energetic processes taking place in the cosmos. Faithful to the olympic slogan ''higher, faster, further'', an increasing armada of {gamma}-ray satellites was built and launched over the last couple of decades with Fermi being the youngest of its kind. In this thesis, I use data from the Gamma-Ray Burst Monitor (GBM) onboard the Fermi satellite. The focus of this work lies on three very different classes of high-energy astrophysical transients: Gamma-Ray Bursts (GRBs), solar flares and Soft Gamma Repeaters (SGRs). In Chapter 2, I present GRB 091024A, a burst of very long duration in {gamma}-rays where optical data could be acquired well during its active phase. The optical light curve shows very intriguing features which I subsequently interpret as the so called ''optical flash'', a fundamental property of the ''fireball'' model. Although predicted by the latter model, only a handful of GRBs show such a behavior, making them interesting transients to study. Furthermore, I present the fundamental temporal and spectral properties of 47 GBM-detected GRBs with known redshifts. As GRBs explode at cosmological distances it is of uttermost importance to study them in their restframe to get a better understanding of their emission mechanisms. I confirm several correlations already found in the past together with an intriguing connection between redshift and the peak energy (E{sub peak}) of GRBs. Although this correlation is heavily influenced by instrumental effects, it is not unexpected from other experimental results, giving it more credibility

  9. The Transient High Energy Sky and Early Universe Surveyor

    Science.gov (United States)

    O'Brien, P. T.

    2016-04-01

    The Transient High Energy Sky and Early Universe Surveyor is a mission which will be proposed for the ESA M5 call. THESEUS will address multiple components in the Early Universe ESA Cosmic Vision theme:4.1 Early Universe,4.2 The Universe taking shape, and4.3 The evolving violent Universe.THESEUS aims at vastly increasing the discovery space of the high energy transient phenomena over the entire cosmic history. This is achieved via a unique payload providing an unprecedented combination of: (i) wide and deep sky monitoring in a broad energy band(0.3 keV-20 MeV; (ii) focusing capabilities in the soft X-ray band granting large grasp and high angular resolution; and (iii) on board near-IR capabilities for immediate transient identification and first redshift estimate.The THESEUS payload consists of: (i) the Soft X--ray Imager (SXI), a set of Lobster Eye (0.3--6 keV) telescopes with CCD detectors covering a total FOV of 1 sr; (ii) the X--Gamma-rays spectrometer (XGS), a non-imaging spectrometer (XGS) based on SDD+CsI, covering the same FOV than the Lobster telescope extending the THESEUS energy band up to 20 MeV; and (iii) a 70cm class InfraRed Telescope (IRT) observing up to 2 microns with imaging and moderate spectral capabilities.The main scientific goals of THESEUS are to:(a) Explore the Early Universe (cosmic dawn and reionization era) by unveiling the Gamma--Ray Burst (GRBs) population in the first billion years}, determining when did the first stars form, and investigating the re-ionization epoch, the interstellar medium (ISM) and the intergalactic medium (IGM) at high redshifts.(b) Perform an unprecedented deep survey of the soft X-ray transient Universe in order to fill the present gap in the discovery space of new classes of transient; provide a fundamental step forward in the comprehension of the physics of various classes of Galactic and extra--Galactic transients, and provide real time trigger and accurate locations of transients for follow-up with next

  10. Laser fusion and high energy density science

    International Nuclear Information System (INIS)

    Kodama, Ryosuke

    2005-01-01

    High-power laser technology is now opening a variety of new fields of science and technology using laser-produced plasmas. The laser plasma is now recognized as one of the important tools for the investigation and application of matter under extreme conditions, which is called high energy density science. This chapter shows a variety of applications of laser-produced plasmas as high energy density science. One of the more attractive industrial and science applications is the generation of intense pulse-radiation sources, such as the generation of electro-magnetic waves in the ranges of EUV (Extreme Ultra Violet) to gamma rays and laser acceleration of charged particles. The laser plasma is used as an energy converter in this regime. The fundamental science applications of high energy density physics are shown by introducing laboratory astrophysics, the equation of state of high pressure matter, including warm dense matter and nuclear science. Other applications are also presented, such as femto-second laser propulsion and light guiding. Finally, a new systematization is proposed to explore the possibility of the high energy density plasma application, which is called high energy plasma photonics''. This is also exploration of the boundary regions between laser technology and beam optics based on plasma physics. (author)

  11. Physics at high energy photon photon colliders

    International Nuclear Information System (INIS)

    Chanowitz, M.S.

    1994-06-01

    I review the physic prospects for high energy photon photon colliders, emphasizing results presented at the LBL Gamma Gamma Collider Workshop. Advantages and difficulties are reported for studies of QCD, the electroweak gauge sector, supersymmetry, and electroweak symmetry breaking

  12. Organisation of high-energy physics

    CERN Document Server

    Kluyver, J C

    1981-01-01

    Tabulates details of major accelerator laboratories in western Europe, USA, and USSR, and describes the various organisations concerned with high-energy physics. The Dutch organisation uses the NIKHEF laboratory in Amsterdam and cooperates with CERN. (0 refs).

  13. New informative techniques in high energy physics

    International Nuclear Information System (INIS)

    Klimenko, S.V.; Ukhov, V.I.

    1992-01-01

    A number of new informative techniques applied to high energy physics are considered. These are the object-oriented programming, systems integration, UIMS, visualisation, expert systems, neural networks. 100 refs

  14. Multiplicity distributions in high energy collisions

    International Nuclear Information System (INIS)

    Giovannini, A.; Lupia, S.; Ugoccioni, R.

    1992-01-01

    We discuss the important phases in the evolution of our understanding of multiplicity distributions in high energy collisions with particular emphasis to intermittent behavior and shoulder structure problem. (orig.)

  15. Multiplicity distributions in high energy collisions

    Energy Technology Data Exchange (ETDEWEB)

    Giovannini, A.; Lupia, S.; Ugoccioni, R. (Dipt. di Fisica Teorica, Univ. Turin (Italy) INFN, Turin (Italy))

    1992-03-01

    We discuss the important phases in the evolution of our understanding of multiplicity distributions in high energy collisions with particular emphasis to intermittent behavior and shoulder structure problem. (orig.).

  16. The evolution of high energy accelerators

    International Nuclear Information System (INIS)

    Courant, E.D.

    1989-10-01

    In this lecture I would like to trace how high energy particle accelerators have grown from tools used for esoteric small-scale experiments to gigantic projects being hotly debated in Congress as well as in the scientific community

  17. High Energy Density Polymer Film Capacitors

    National Research Council Canada - National Science Library

    Boufelfel, Ali

    2006-01-01

    High-energy-density capacitors that are compact and light-weight are extremely valuable in a number of critical DoD systems that include portable field equipment, pulsed lasers, detection equipment...

  18. Research in High Energy Physics. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Conway, John S.

    2013-08-09

    This final report details the work done from January 2010 until April 2013 in the area of experimental and theoretical high energy particle physics and cosmology at the University of California, Davis.

  19. Studies In Theoretical High Energy Particle Physics

    Energy Technology Data Exchange (ETDEWEB)

    Keung, Wai Yee [Univ. of Illinois, Chicago, IL (United States)

    2017-07-01

    This is a final technical report for grant no. DE-SC0007948 describing research activities in theoretical high energy physics at University of Illinois at Chicago for the whole grant period from July 1, 2012 to March 31, 2017.

  20. Proceedings of progress in high energy physics

    International Nuclear Information System (INIS)

    Pauchy Hwang, W.Y.; Lee, S.C.; Lee, C.E.; Ernst, D.J.

    1991-01-01

    This book contains the proceedings of progress in high energy physics. Topics covered include: Particle Phenomology; Particles and Fields; Physics in 2 and 1 Dimensions; Cosmology, Astrophysics, and Gravitation; Some Perspertives on the Future of Particle Physics

  1. Integrated high voltage power supply utilizing burst mode control and its performance impact on dielectric electro active polymer actuators

    DEFF Research Database (Denmark)

    Andersen, Thomas; Rødgaard, Martin Schøler; Andersen, Michael A. E.

    Through resent years new high performing Dielectric Electro Active Polymers (DEAP) have emerged. To fully utilize the potential of DEAPs a driver with high voltage output is needed. In this paper a piezoelectric transformer based power supply for driving DEAP actuators is developed, utilizing...

  2. Elementary particle physics and high energy phenomena

    International Nuclear Information System (INIS)

    Barker, A.R.; Cumalat, J.P.; de Alwis, S.P.; DeGrand, T.A.; Ford, W.T.; Mahanthappa, K.T.; Nauenberg, U.; Rankin, P.; Smith, J.G.

    1992-06-01

    This report discusses the following research in high energy physics: the properties of the z neutral boson with the SLD detector; the research and development program for the SDC muon detector; the fixed-target k-decay experiments; the Rocky Mountain Consortium for HEP; high energy photoproduction of states containing heavy quarks; and electron-positron physics with the CLEO II and Mark II detectors. (LSP)

  3. Scaling violations at ultra-high energies

    International Nuclear Information System (INIS)

    Tung, W.K.

    1979-01-01

    The paper discusses some of the features of high energy lepton-hadron scattering, including the observed (Bjorken) scaling behavior. The cross-sections where all hadron final states are summed over, are examined and the general formulas for the differential cross-section are examined. The subjects of scaling, breaking and phenomenological consequences are studied, and a list of what ultra-high energy neutrino physics can teach QCD is given

  4. Elementary particle physics and high energy phenomena

    Energy Technology Data Exchange (ETDEWEB)

    Barker, A.R.; Cumalat, J.P.; de Alwis, S.P.; DeGrand, T.A.; Ford, W.T.; Mahanthappa, K.T.; Nauenberg, U.; Rankin, P.; Smith, J.G.

    1992-06-01

    This report discusses the following research in high energy physics: the properties of the z neutral boson with the SLD detector; the research and development program for the SDC muon detector; the fixed-target k-decay experiments; the Rocky Mountain Consortium for HEP; high energy photoproduction of states containing heavy quarks; and electron-positron physics with the CLEO II and Mark II detectors. (LSP).

  5. Research of high energy radioactivity identification detector

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yong Kyun; Lee, Yong Bum; Hwang, Jong Sun; Choi, Seok Ki

    1998-07-01

    {Delta} {Epsilon}-{Epsilon} telescope high radioactivity detector was designed, fabricated, and tested at the 35 MeV proton energy. We developed the computer code to calculate the energy loss of projectile ions in the matter. Using the code, we designed and fabricated a detector to measure 15-50 MeV protons. The detector was successfully tested to measure the energy of protons and deuterons and to identify the ions. In future, we would like to extend the present result to the development of a higher energy proton detector and a heavy ion detector. (author). 10 refs., 3 tabs., 14 figs

  6. High-energy cosmic-ray acceleration

    CERN Document Server

    Bustamante, M; de Paula, W; Duarte Chavez, J A; Gago, A M; Hakobyan, H; Jez, P; Monroy Montañez, J A; Ortiz Velasquez, A; Padilla Cabal, F; Pino Rozas, M; Rodriguez Patarroyo, D J; Romeo, G L; Saldaña-Salazar , U J; Velasquez, M; von Steinkirch, M

    2010-01-01

    We briefly review the basics of ultrahigh-energy cosmic-ray acceleration. The Hillas criterion is introduced as a geometrical criterion that must be fulfilled by potential acceleration sites, and energy losses are taken into account in order to obtain a more realistic scenario. The different available acceleration mechanisms are presented, with special emphasis on Fermi shock acceleration and its prediction of a power-law cosmic-ray energy spectrum. We conclude that first-order Fermi acceleration, though not entirely satisfactory, is the most promising mechanism for explaining the ultra-high-energy cosmic-ray flux.

  7. Star formation rates and stellar masses in z ~ 1 gamma-ray burst hosts

    DEFF Research Database (Denmark)

    Castro Cerón, José María; Michalowski, Michal; Hjorth, J.

    2006-01-01

    Cosmology: Observations, ISM: Dust, Extinction, Galaxies: High-Redshift, Galaxies: ISM, Gamma Rays: Bursts, Infrared: Galaxies Udgivelsesdato: Dec. 4......Cosmology: Observations, ISM: Dust, Extinction, Galaxies: High-Redshift, Galaxies: ISM, Gamma Rays: Bursts, Infrared: Galaxies Udgivelsesdato: Dec. 4...

  8. Report on high energy neutron dosimetry workshop

    International Nuclear Information System (INIS)

    Alvar, K.R.; Gavron, A.

    1993-01-01

    The workshop was called to assess the performance of neutron dosimetry per the responses from ten DOE accelerator facilities to an Office of Energy Research questionnaire regarding implementation of a personnel dosimetry requirement in DRAFT DOE 5480.ACC, ''Safety of Accelerator Facilities''. The goals of the workshop were to assess the state of dosimetry at high energy accelerators and if such dosimetry requires improvement, to reach consensus on how to proceed with such improvements. There were 22 attendees, from DOE Programs and contract facilities, DOE, Office of Energy Research (ER), Office of Environmental Safety and Health (EH), Office of Fusion Energy, and the DOE high energy accelerator facilities. A list of attendees and the meeting agenda are attached. Copies of the presentations are also attached

  9. Ultra-High-Energy Cosmic Rays

    CERN Document Server

    Dova, M.T.

    2015-05-22

    The origin of the ultra high energy cosmic rays (UHECR) with energies above E > 10 17 eV, is still unknown. The discovery of their sources will reveal the engines of the most energetic astrophysical accelerators in the universe. This is a written version of a series of lectures devoted to UHECR at the 2013 CERN-Latin-American School of High-Energy Physics. We present anintroduction to acceleration mechanisms of charged particles to the highest energies in astrophysical objects, their propagation from the sources to Earth, and the experimental techniques for their detection. We also discuss some of the relevant observational results from Telescope Array and Pierre Auger Observatory. These experiments deal with particle interactions at energies orders of magnitude higher than achieved in terrestrial accelerators.

  10. Cosmic physics: the high energy frontier

    International Nuclear Information System (INIS)

    Stecker, F W

    2003-01-01

    Cosmic rays have been observed up to energies 10 8 times larger than those of the best particle accelerators. Studies of astrophysical particles (hadrons, neutrinos and photons) at their highest observed energies have implications for fundamental physics as well as astrophysics. Thus, the cosmic high energy frontier is the nexus to new particle physics. This overview discusses recent advances being made in the physics and astrophysics of cosmic rays and cosmic γ-rays at the highest observed energies as well as the related physics and astrophysics of very high energy cosmic neutrinos. These topics touch on questions of grand unification, violations of Lorentz invariance as well as Planck scale physics and quantum gravity. (topical review)

  11. Nanolensed Fast Radio Bursts

    Science.gov (United States)

    Eichler, David

    2017-12-01

    It is suggested that fast radio bursts can probe gravitational lensing by clumpy dark matter objects that range in mass from 10-3 M ⊙-102 M ⊙. They may provide a more sensitive probe than observations of lensings of objects in the Magellanic Clouds, and could find or rule out clumpy dark matter with an extended mass spectrum.

  12. High-energy astrophysics and the search for sources of gravitational waves.

    Science.gov (United States)

    O'Brien, P T; Evans, P

    2018-05-28

    The dawn of the gravitational-wave (GW) era has sparked a greatly renewed interest into possible links between sources of high-energy radiation and GWs. The most luminous high-energy sources-gamma-ray bursts (GRBs)-have long been considered as very likely sources of GWs, particularly from short-duration GRBs, which are thought to originate from the merger of two compact objects such as binary neutron stars and a neutron star-black hole binary. In this paper, we discuss: (i) the high-energy emission from short-duration GRBs; (ii) what other sources of high-energy radiation may be observed from binary mergers; and (iii) how searches for high-energy electromagnetic counterparts to GW events are performed with current space facilities. While current high-energy facilities, such as Swift and Fermi, play a crucial role in the search for electromagnetic counterparts, new space missions will greatly enhance our capabilities for joint observations. We discuss why such facilities, which incorporate new technology that enables very wide-field X-ray imaging, are required if we are to truly exploit the multi-messenger era.This article is part of a discussion meeting issue 'The promises of gravitational-wave astronomy'. © 2018 The Author(s).

  13. High-energy astrophysics and the search for sources of gravitational waves

    Science.gov (United States)

    O'Brien, P. T.; Evans, P.

    2018-05-01

    The dawn of the gravitational-wave (GW) era has sparked a greatly renewed interest into possible links between sources of high-energy radiation and GWs. The most luminous high-energy sources-gamma-ray bursts (GRBs)-have long been considered as very likely sources of GWs, particularly from short-duration GRBs, which are thought to originate from the merger of two compact objects such as binary neutron stars and a neutron star-black hole binary. In this paper, we discuss: (i) the high-energy emission from short-duration GRBs; (ii) what other sources of high-energy radiation may be observed from binary mergers; and (iii) how searches for high-energy electromagnetic counterparts to GW events are performed with current space facilities. While current high-energy facilities, such as Swift and Fermi, play a crucial role in the search for electromagnetic counterparts, new space missions will greatly enhance our capabilities for joint observations. We discuss why such facilities, which incorporate new technology that enables very wide-field X-ray imaging, are required if we are to truly exploit the multi-messenger era. This article is part of a discussion meeting issue `The promises of gravitational-wave astronomy'.

  14. Recent achievements in the field of gamma-ray bursts

    International Nuclear Information System (INIS)

    Lu Tan; Dai Zigao

    2001-01-01

    Recent progresses in the field of gamma-ray bursts is briefly introduced. Gamma-ray bursts are the most energetic explosion since the Big Bang of the universe. Within a few tens of seconds, the energy released in gamma-ray bursts could be several hundred times larger than that released form the sun in its whole life (about 10 billion years). The authors will first briefly discuss the observational facts, based on which the authors will discuss the standard fireball model, the dynamical behavior and evolution of gamma-ray bursts and their afterglows. Then, various observational phenomena that contradict the standard model are given and the importance of these post-standard effects are pointed out. The questions related to the energy source of gamma-ray bursts are still unanswered, and other important questions also remain to be solved

  15. Extraction of microseismic waveforms characteristics prior to rock burst using Hilbert-Huang transform

    Science.gov (United States)

    Li, Xuelong; Li, Zhonghui; Wang, Enyuan; Feng, Junjun; Chen, Liang; Li, Nan; Kong, Xiangguo

    2016-09-01

    This study provides a new research idea concerning rock burst prediction. The characteristics of microseismic (MS) waveforms prior to and during the rock burst were studied through the Hilbert-Huang transform (HHT). In order to demonstrate the advantage of the MS features extraction based on HHT, the conventional analysis method (Fourier transform) was also used to make a comparison. The results show that HHT is simple and reliable, and could extract in-depth information about the characteristics of MS waveforms. About 10 days prior to the rock burst, the main frequency of MS waveforms transforms from the high-frequency to low-frequency. What's more, the waveforms energy also presents accumulation characteristic. Based on our study results, it can be concluded that the MS signals analysis through HHT could provide valuable information about the coal or rock deformation and fracture.

  16. High energy physics advisory panel's subpanel on vision for the future of high-energy physics

    International Nuclear Information System (INIS)

    1994-05-01

    This report was requested by the Secretary of Energy to (1) define a long-term program for pursuing the most important high-energy physics goals since the termination of the Superconducting Super Collider (SSC) project, (2) assess the current US high-energy physics program, and (3) make recommendations regarding the future of the field. Subjects on which recommendations were sought and which the report addresses were: high-energy physics funding priorities; facilitating international collaboration for future construction of large high-energy physics facilities; optimizing uses of the investment made in the SSC; how to encourage displaced scientists and engineers to remain in high-energy physics and to attract young scientists to enter the field in the future. The report includes a description of the state of high-energy physics research in the context of history, a summary of the SSC project, and documentation of the report's own origins and development

  17. HOW SOFT GAMMA REPEATERS MIGHT MAKE FAST RADIO BURSTS

    Energy Technology Data Exchange (ETDEWEB)

    Katz, J. I., E-mail: katz@wuphys.wustl.edu [Department of Physics and McDonnell Center for the Space Sciences, Washington University, St. Louis, Mo. 63130 (United States)

    2016-08-01

    There are several phenomenological similarities between soft gamma repeaters (SGRs) and fast radio bursts (FRBs), including duty factors, timescales, and repetition. The sudden release of magnetic energy in a neutron star magnetosphere, as in popular models of SGRs, can meet the energy requirements of FRBs, but requires both the presence of magnetospheric plasma, in order for dissipation to occur in a transparent region, and a mechanism for releasing much of that energy quickly. FRB sources and SGRs are distinguished by long-lived (up to thousands of years) current-carrying coronal arches remaining from the formation of the young neutron star, and their decay ends the phase of SGR/AXP/FRB activity even though “magnetar” fields may persist. Runaway increases in resistance when the current density exceeds a threshold, releases magnetostatic energy in a sudden burst, and produces high brightness GHz emission of FRB by a coherent process. SGRs are produced when released energy thermalizes as an equlibrium pair plasma. The failures of some alternative FRB models and the non-detection of SGR 1806-20 at radio frequencies are discussed in the appendices.

  18. HOW SOFT GAMMA REPEATERS MIGHT MAKE FAST RADIO BURSTS

    International Nuclear Information System (INIS)

    Katz, J. I.

    2016-01-01

    There are several phenomenological similarities between soft gamma repeaters (SGRs) and fast radio bursts (FRBs), including duty factors, timescales, and repetition. The sudden release of magnetic energy in a neutron star magnetosphere, as in popular models of SGRs, can meet the energy requirements of FRBs, but requires both the presence of magnetospheric plasma, in order for dissipation to occur in a transparent region, and a mechanism for releasing much of that energy quickly. FRB sources and SGRs are distinguished by long-lived (up to thousands of years) current-carrying coronal arches remaining from the formation of the young neutron star, and their decay ends the phase of SGR/AXP/FRB activity even though “magnetar” fields may persist. Runaway increases in resistance when the current density exceeds a threshold, releases magnetostatic energy in a sudden burst, and produces high brightness GHz emission of FRB by a coherent process. SGRs are produced when released energy thermalizes as an equlibrium pair plasma. The failures of some alternative FRB models and the non-detection of SGR 1806-20 at radio frequencies are discussed in the appendices.

  19. Department of High Energy Physics - Overview

    International Nuclear Information System (INIS)

    Bialkowska, H.

    2006-01-01

    The activities of the Department are centered around experiments performed at large accelerator laboratories: I. At CERN, the European Laboratory for Particle Physics in Geneva, Switzerland: - Data taking experiments: COMPASS (Compact Muon and Proton Apparatus for Structure and Spectroscopy) - studies of the gluon polarization in the nucleon; - Experiments that finished data taking but continue the analysis: NA49 and WA98 - heavy ion experiments, study hadronic and nuclear interactions, searching for the quark-gluon plasma. II. The 'Pi of the Sky' experiment, searching for optical flashes associated with Gamma Ray Bursts takes data with a set of CCD cameras mounted in the Chile Observatory Station, and works on an extension of the system. III. WASA experiment, recently transferred from the CELSIUS storage ring in Uppsala to Juelich, studies near threshold resonance production. IV. ZEUS experiment at HERA in Hamburg - studies of proton structure functions and diffractive interactions. V. Neutrino experiments at SuperKamiokande and K2K in Japan - studies of the neutrino oscillations. VI. Preparations for future experiments: a) ICARUS - in preparation for the neutrino beam from CERN, to study neutrino oscillations, b) Experiments at the future Large Hadron Collider at CERN: CMS - Compact Muon Solenoid, LHCb - study of b-quark production, ALICE - study of heavy ion collisions. A team of physicists, engineers and technicians, using our well equipped mechanical workshop, with 'clean room' (class 100 000) facilities has performed a large scale production of straw tube modules for the LHCb experiment. Preparations for LHC physics requires an active participation of the teams involved in the computer GRID implementation. There is also a small group involved in theoretical work on the phenomenology of quark-gluon plasma formation and the low energy hadronic reactions. Several physicists from our department are actively involved in science popularization. A close

  20. The high energy accelerator program in Japan

    International Nuclear Information System (INIS)

    Ozaki, S.

    1987-01-01

    The author observes that in order to survey the intentions of Japanese high energy physicists and to make a recommendation to the High Energy Committee on future plans for high energy physics in Japan, including accelerators after TRISTAN, international collaboration projects and non-accelerator physics, a subcommittee of fifteen members is formed. The committee recommendation reads: A) For a new energy frontier, 1. Immediate initiation of R/D efforts for an e/sup +/e/sup -/ linear collider of TeV class, constructs a possible home-based facility, 2. Promotes international collaborative experiments using the SSC for the hadron sector, B) As projects of immediate concern: 1. The energy of the TRISTAN main ring increases further makes a possible low energy, high luminosity e/sup +/e/sup -/ collider operation in the TRISTAN complex, 2. The intensity of the 12 GeV PS at KEK increases, 3. Experiments in non-accelerator particle physics are promoted. In this contribution, the current status of the TRISTAN project and some of the R/D program on accelerator technology are reported

  1. Indiana University High Energy Physics, Task A

    International Nuclear Information System (INIS)

    Brabson, B.; Crittenden, R.; Dzierba, A.

    1993-01-01

    This report discusses research at Indians University on the following high energy physics experiments: A search for mesons with unusual quantum numbers; hadronic states produced in association with high-mass dimuons; FNAL E740 (D0); superconducting super collider; and OPAL experiment at CERN

  2. High energy experimental physics: Progress report

    International Nuclear Information System (INIS)

    Rosen, J.; Miller, D.

    1988-01-01

    This report contains papers of high energy physics experiments and detector equipment design. Proposals are also given for future experiments. Some of the topics covered in this report are: high energy predictions for /bar char/pp and pp elastic scattering and total cross sections; D0 forward drift chambers; polarized beam facility; analyzing power measurment in inclusive pion production at high transverse momentum; Skyrme model for baryons; string models for color flux tubes; hadronic decays for the /tau/ lepton; and meson form factors in perturbative QCD

  3. High-energy air shock study in steel and grout pipes

    International Nuclear Information System (INIS)

    Glenn, H.D.; Kratz, H.R.; Keough, D.D.; Duganne, D.A.; Ruffner, D.J.; Swift, R.P.; Baum, D.

    1979-01-01

    Voitenko compressors are used to generate 43 mm/μs air shocks in both a steel and a grout outlet pipe containing ambient atmospheric air. Fiber-optic ports provide diaphragm burst times, time-of-arrival (TOA) data, and velocities for the shock front along the 20-mm-ID exit pipes. Pressure profiles are obtained at higher enthalpy shock propagation than ever before and at many locations along the exit pipes. Numerous other electronic sensors and postshot observations are described, as well as experimental results. The primary objectives of the experiments are as follows: (1) provide a data base for normalization/improvement of existing finite-difference codes that describe high-energy air shocks and gas propagation; (2) obtain quantitative results on the relative attenuation effects of two very different wall materials for high-energy air shocks and gas flows. The extensive experimental results satisfy both objectives

  4. Multi-Index Monitoring and Evaluation on Rock Burst in Yangcheng Mine

    OpenAIRE

    Tan, Yunliang; Yin, Yanchun; Gu, Shitan; Tian, Zhiwei

    2015-01-01

    Based on the foreboding information monitoring of the energy released in the developing process of rock burst, prediction system for rock burst can be established. By using microseismic method, electromagnetic radiation method, and drilling bits method, rock burst in Yangcheng Mine was monitored, and a system of multi-index monitoring and evaluation on rock burst was established. Microseismic monitoring and electromagnetic radiation monitoring were early warning method, and drilling bits moni...

  5. The LAGO Collaboration: Searching for high energy GRB emissions in Latin America

    Science.gov (United States)

    Barros, H.; Lago Collaboration

    2012-02-01

    During more than a decade Gamma Ray Bursts (GRB a cosmological phenomena of tremendous power) have been extensively studied in the keV - MeV energy range. However, the higher energy emission still remains a mystery. The Large Aperture GRB Observatory (L.A.G.O.) is an international collaboration started in 2005 aiming at a better understanding of the GRB by studying their emission at high energies (> 1 GeV), where the fluxes are low and measurements by satellites are difficult. This is done using the Single Particle Technique, by means of ground-based Water Cherenkov Detectors (WCD) at sites of high altitude. At those altitudes it is possible to detect air showers produced by high energy photons from the GRB, i. e. a higher rate of events on a short time scale, of the order of the second. The Pierre Auger Observatory could detect such GRB given its large number of detectors, but at 1400 m.a.s.l. the expected signal is quite small. At higher altitudes, similar performance is expected with only a very small number of WCD. As of 2011, high altitude WCD are in operation at Sierra Negra (Mexico, 4650 m.a.s.l.), Chacaltaya (Bolivia, 5200 m.a.s.l.), Maracapomacocha (Peru, 4200 m.a.s.l.), and new WCDs are being installed in Venezuela (Pico Espejo, 4750 m.a.s.l.), Argentina, Brazil, Chile, Colombia and Guatemala. Most of the new WCDs will not be at high enough altitude to detect GRB, never the less it will allow obtaining valuable measurements of secondaries at ground level, which are relevant for solar physics. The LAGO sensitivity to GRB is determined from simulations (under a sudden increase of 1 GeV - 1 TeV photons from a GRB) of the gamma initiated particle shower in the atmosphere and the WCD response to secondaries. We report on WDC calibration and operation at high altitude, GRB detectability, background rates, search for bursts in several months of preliminary data, as well as search for signals at ground level when satellite burst is reported, all these show the

  6. Opportunities for high wind energy penetration

    DEFF Research Database (Denmark)

    Tande, J.O.; Hansen, J.C.

    1997-01-01

    Wind power is today a mature technology, which at windy locations, is economically competitive to conventional power generation technologies. This and growing global environmental concerns have led governments to encourage and plan for wind energy development, a typical aim being 10% of electricity...... consumption. The successful operation of the three major power systems of Cape Verde, with a total wind energy penetration of about 15% since December 1994, demonstrates that power systems can be operated with high penetration of wind energy by adding simple control and monitoring systems only. Thorough...... analyses conclude that expanding to even above 15% wind energy penetration in the Cape Verde power systems is economical. Worldwide, numerous locations with favorable wind conditions and power systems similar to the Capeverdean provide good opportunities for installing wind farms and achieving high wind...

  7. High-energy capacitance electrostatic micromotors

    Science.gov (United States)

    Baginsky, I. L.; Kostsov, E. G.

    2003-03-01

    The design and parameters of a new electrostatic micromotor with high energy output are described. The motor is created by means of microelectronic technology. Its operation is based on the electromechanic energy conversion during the electrostatic rolling of the metallic films (petals) on the ferroelectric film surface. The mathematical simulation of the main characteristics of the rolling process is carried out. The experimentally measured parameters of the petal step micromotors are shown. The motor operation and its efficiency are investigated.

  8. High energy collisions of nuclei: experiments

    International Nuclear Information System (INIS)

    Heckman, H.H.

    1977-09-01

    Heavy-ion nuclear reactions with projectile energies up to 2.1 GeV/A are reviewed. The concept of ''rapidity'' is elucidated, and the reactions discussed are divided into sections dealing with target fragmentation, projectile fragmentation, and the intermediate region, with emphasis on the production of light nuclei in high-energy heavy-ion collisions. Target fragmentation experiments using nuclear emulsion and AgCl visual track detectors are also summarized. 18 figures

  9. High energy cosmic rays: sources and fluxes

    Energy Technology Data Exchange (ETDEWEB)

    Stanev, Todor; Gaisser, Thomas K.; Tilav, Serap

    2014-04-01

    We discuss the production of a unique energy spectrum of the high energy cosmic rays detected with air showers by shifting the energy estimates of different detectors. After such a spectrum is generated we fit the spectrum with three or four populations of cosmic rays that might be accelerated at different cosmic ray sources. We also present the chemical composition that the fits of the spectrum generates and discuss some new data sets presented this summer at the ICRC in Rio de Janeiro that may require new global fits.

  10. Hardon cross sections at ultra high energies

    International Nuclear Information System (INIS)

    Yodh, G.B.

    1987-01-01

    A review of results on total hadronic cross sections at ultra high energies obtained from a study of longitudinal development of cosmic ray air showers is given. The experimental observations show that proton-air inelastic cross section increases from 275 mb to over 500 mb as the collision energy in the center of mass increases from 20 GeV to 20 TeV. The proton-air inelastic cross section, obtained from cosmic ray data at √s = 30 TeV, is compared with calculations using various different models for the energy variation of the parameters of the elementary proton-proton interaction. Three conclusions are derived

  11. Exogenous Trehalose Largely Alleviates Ionic Unbalance, ROS Burst and PCD Occurrence Induced by High Salinity in Arabidopsis Seedlings

    Directory of Open Access Journals (Sweden)

    Lei eYang

    2014-10-01

    Full Text Available Trehalose (Tre has been reported to play a critical role in plant response to salinity and the involved mechanisms remain to be investigated in detail. Here, the putative roles of Tre in regulation of ionic balance, cellular redox state, cell death were studied in Arabidopsis under high salt condition. Our results found that the salt-induced restrictions on both vegetative and reproductive growth in salt-stressed plants were largely alleviated by exogenous supply with Tre. The microprobe analysis of ionic dynamics in the leaf and stem of florescence highlighted the Tre ability to retain K and K/Na ratio in plant tissues to improve salt tolerance. The flow cytometric (FCM assay of cellular levels of ROS (reactive oxygen species and PCD (programmed cell death displayed that Tre was able to antagonized salt-induced damages in redox state and cell death and sucrose did not play the same role with Tre. By comparing ionic distribution in leaf and IS (inflorescence stem, we found that Tre was able to restrict Na transportation to IS from leaves since that the ratio of Na accumulation in leaves relative to IS was largely improved due to Tre. The marked decrease of Na ion and improved sucrose level in IS might account for the promoted floral growth when Tre was included in the saline solution. At the same time, endogenous soluble sugars and antioxidant enzyme activities in the salt-stressed plants were also elevated by Tre to counteract high salt stress. We concluded that Tre could improve Arabidopsis salt resistance with respect to biomass accumulation and floral transition in the means of regulating plant redox state, cell death and ionic distribution.

  12. High Energy Density Sciences with High Power Lasers at SACLA

    Science.gov (United States)

    Kodama, Ryosuke

    2013-10-01

    One of the interesting topics on high energy density sciences with high power lasers is creation of extremely high pressures in material. The pressures of more than 0.1 TPa are the energy density corresponding to the chemical bonding energy, resulting in expectation of dramatic changes in the chemical reactions. At pressures of more than TPa, most of material would be melted on the shock Hugoniot curve. However, if the temperature is less than 1eV or lower than a melting point at pressures of more than TPa, novel solid states of matter must be created through a pressured phase transition. One of the interesting materials must be carbon. At pressures of more than TPa, the diamond structure changes to BC and cubic at more than 3TPa. To create such novel states of matter, several kinds of isentropic-like compression techniques are being developed with high power lasers. To explore the ``Tera-Pascal Science,'' now we have a new tool which is an x-ray free electron laser as well as high power lasers. The XFEL will clear the details of the HED states and also efficiently create hot dense matter. We have started a new project on high energy density sciences using an XFEL (SACLA) in Japan, which is a HERMES (High Energy density Revolution of Matter in Extreme States) project.

  13. Revisiting the dispersion measure of fast radio bursts associated with gamma-ray burst afterglows

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Yun-Wei, E-mail: yuyw@mail.ccnu.edu.cn [Institute of Astrophysics, Central China Normal University, Wuhan 430079 (China)

    2014-12-01

    Some fast radio bursts (FRBs) are expected to be associated with the afterglow emission of gamma-ray bursts (GRBs), while a short-lived, supermassive neutron star (NS) forms during the GRBs. I investigate the possible contributions to the dispersion measure (DM) of the FRBs from the GRB ejecta and the wind blown from the precollapsing NS. On the one hand, sometimes an internal X-ray plateau afterglow could be produced by the NS wind, which indicates that a great number of electron-positron pairs are carried by the wind. If the pair-generation radius satisfies a somewhat rigorous condition, the relativistic and dense wind would contribute a high DM to the associated FRB, which can be comparable to and even exceed the DM contributed by the intergalactic medium. On the other hand, if the wind only carries a Goldreich-Julian particle flux, its DM contribution would become negligible; meanwhile, the internal plateau afterglow would not appear. Alternatively, the FRB should be associated with a GRB afterglow produced by the GRB external shock, i.e., an energy-injection-caused shallow-decay afterglow or a normal single-power-law afterglow if the impulsive energy release of the GRB is high enough. In the latter case, the DM contributed by the high-mass GRB ejecta could be substantially important, in particular, for an environment of main-sequence stellar wind. In summary, a careful assessment on the various DM contributors could be required for the cosmological application of the expected FRB-GRB association. The future DM measurements of GRB-associated FRBs could provide a constraint on the physics of NS winds.

  14. Revisiting the dispersion measure of fast radio bursts associated with gamma-ray burst afterglows

    International Nuclear Information System (INIS)

    Yu, Yun-Wei

    2014-01-01

    Some fast radio bursts (FRBs) are expected to be associated with the afterglow emission of gamma-ray bursts (GRBs), while a short-lived, supermassive neutron star (NS) forms during the GRBs. I investigate the possible contributions to the dispersion measure (DM) of the FRBs from the GRB ejecta and the wind blown from the precollapsing NS. On the one hand, sometimes an internal X-ray plateau afterglow could be produced by the NS wind, which indicates that a great number of electron-positron pairs are carried by the wind. If the pair-generation radius satisfies a somewhat rigorous condition, the relativistic and dense wind would contribute a high DM to the associated FRB, which can be comparable to and even exceed the DM contributed by the intergalactic medium. On the other hand, if the wind only carries a Goldreich-Julian particle flux, its DM contribution would become negligible; meanwhile, the internal plateau afterglow would not appear. Alternatively, the FRB should be associated with a GRB afterglow produced by the GRB external shock, i.e., an energy-injection-caused shallow-decay afterglow or a normal single-power-law afterglow if the impulsive energy release of the GRB is high enough. In the latter case, the DM contributed by the high-mass GRB ejecta could be substantially important, in particular, for an environment of main-sequence stellar wind. In summary, a careful assessment on the various DM contributors could be required for the cosmological application of the expected FRB-GRB association. The future DM measurements of GRB-associated FRBs could provide a constraint on the physics of NS winds.

  15. DETECTION OF HIGH-ENERGY GAMMA-RAY EMISSION DURING THE X-RAY FLARING ACTIVITY IN GRB 100728A

    International Nuclear Information System (INIS)

    Abdo, A. A.; Ackermann, M.; Ajello, M.; Bechtol, K.; Berenji, B.; Blandford, R. D.; Borgland, A. W.; Baldini, L.; Bellazzini, R.; Bregeon, J.; Ballet, J.; Barbiellini, G.; Baring, M. G.; Bastieri, D.; Bhat, P. N.; Bissaldi, E.; Bonamente, E.; Bonnell, J.; Bouvier, A.; Brigida, M.

    2011-01-01

    We present the simultaneous Swift and Fermi observations of the bright GRB 100728A and its afterglow. The early X-ray emission is dominated by a vigorous flaring activity continuing until 1 ks after the burst. In the same time interval, high-energy emission is significantly detected by the Fermi/Large Area Telescope. Marginal evidence of GeV emission is observed up to later times. We discuss the broadband properties of this burst within both the internal and external shock scenarios, with a particular emphasis on the relation between X-ray flares, the GeV emission, and a continued long-duration central engine activity as their power source.

  16. High-energy hadron-hadron collisions

    International Nuclear Information System (INIS)

    Yang, C.N.

    1983-01-01

    While high energy collision experiments yield a wealth of complicated patterns, there are a few general and very striking features that stand out. Because of the universality of these features, and because of the dominating influence they have on high energy phenomena, it is the authors opinion that a physical picture of high energy collisions must address itself first of all to these features before going into specific details. In this short talk these general and striking features are stated and a physical picture developed in the last few years to specifically accommodate these features is described. The picture was originally discussed for elastic scattering. But it leads naturally, indeed inevitably as they shall discuss, to conclusions about inelastic processes, resulting in an idea called the hypothesis of limiting fragmentation

  17. Experimental and theoretical high energy physics research

    International Nuclear Information System (INIS)

    1992-01-01

    Progress in the various components of the UCLA High-Energy Physics Research program is summarized, including some representative figures and lists of resulting presentations and published papers. Principal efforts were directed at the following: (I) UCLA hadronization model, PEP4/9 e + e - analysis, bar P decay; (II) ICARUS and astroparticle physics (physics goals, technical progress on electronics, data acquisition, and detector performance, long baseline neutrino beam from CERN to the Gran Sasso and ICARUS, future ICARUS program, and WIMP experiment with xenon), B physics with hadron beams and colliders, high-energy collider physics, and the φ factory project; (III) theoretical high-energy physics; (IV) H dibaryon search, search for K L 0 → π 0 γγ and π 0 ν bar ν, and detector design and construction for the FNAL-KTeV project; (V) UCLA participation in the experiment CDF at Fermilab; and (VI) VLPC/scintillating fiber R ampersand D

  18. Magnetized environs of a repeating radio burst

    Science.gov (United States)

    Metzger, Brian D.

    2018-03-01

    One of the astrophysical sources that gives rise to the mysterious transients known as fast radio bursts is embedded in a highly magnetized environment, such as the vicinity of an accreting massive black hole or the birth nebula of a highly magnetized neutron star.

  19. The HESP (High Energy Solar Physics) project

    Science.gov (United States)

    Kai, K.

    1986-01-01

    A project for space observations of solar flares for the coming solar maximum phase is briefly described. The main objective is to make a comprehensive study of high energy phenomena of flares through simultaneous imagings in both hard and soft X-rays. The project will be performed with collaboration from US scientists. The HESP (High Energy Solar Physics) WG of ISAS (Institute of Space and Astronautical Sciences) has extensively discussed future aspects of space observations of high energy phenomena of solar flares based on successful results of the Hinotori mission, and proposed a comprehensive research program for the next solar maximum, called the HESP (SOLAR-A) project. The objective of the HESP project is to make a comprehensive study of both high energy phenomena of flares and quiet structures including pre-flare states, which have been left uncovered by SMM and Hinotori. For such a study simultaneous imagings with better resolutions in space and time in a wide range of energy will be extremely important.

  20. FAST RADIO BURSTS AND RADIO TRANSIENTS FROM BLACK HOLE BATTERIES

    Energy Technology Data Exchange (ETDEWEB)

    Mingarelli, Chiara M. F. [TAPIR, MC 350-17, California Institute of Technology, Pasadena, CA 91125 (United States); Levin, Janna [Institute for Strings, Cosmology and Astroparticle Physics (ISCAP), Columbia University, New York, NY 10027 (United States); Lazio, T. Joseph W. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)

    2015-12-01

    Most black holes (BHs) will absorb a neutron star (NS) companion fully intact without tidal disruption, suggesting the pair will remain dark to telescopes. Even without tidal disruption, electromagnetic (EM) luminosity is generated from the battery phase of the binary when the BH interacts with the NS magnetic field. Originally, the luminosity was expected to be in high-energy X-rays or gamma-rays, however, we conjecture that some of the battery power is emitted in the radio bandwidth. While the luminosity and timescale are suggestive of fast radio bursts (FRBs; millisecond-scale radio transients) NS–BH coalescence rates are too low to make these a primary FRB source. Instead, we propose that the transients form a FRB sub-population, distinguishable by a double peak with a precursor. The rapid ramp-up in luminosity manifests as a precursor to the burst which is 20%–80% as luminous given 0.5 ms timing resolution. The main burst arises from the peak luminosity before the merger. The post-merger burst follows from the NS magnetic field migration to the BH, causing a shock. NS–BH pairs are especially desirable for ground-based gravitational wave (GW) observatories since the pair might not otherwise be detected, with EM counterparts greatly augmenting the scientific leverage beyond the GW signal. The EM signal’s ability to break degeneracies in the parameters encoded in the GW and probe the NS magnetic field strength is quite valuable, yielding insights into open problems in NS magnetic field decay.

  1. FAST RADIO BURSTS AND RADIO TRANSIENTS FROM BLACK HOLE BATTERIES

    International Nuclear Information System (INIS)

    Mingarelli, Chiara M. F.; Levin, Janna; Lazio, T. Joseph W.

    2015-01-01

    Most black holes (BHs) will absorb a neutron star (NS) companion fully intact without tidal disruption, suggesting the pair will remain dark to telescopes. Even without tidal disruption, electromagnetic (EM) luminosity is generated from the battery phase of the binary when the BH interacts with the NS magnetic field. Originally, the luminosity was expected to be in high-energy X-rays or gamma-rays, however, we conjecture that some of the battery power is emitted in the radio bandwidth. While the luminosity and timescale are suggestive of fast radio bursts (FRBs; millisecond-scale radio transients) NS–BH coalescence rates are too low to make these a primary FRB source. Instead, we propose that the transients form a FRB sub-population, distinguishable by a double peak with a precursor. The rapid ramp-up in luminosity manifests as a precursor to the burst which is 20%–80% as luminous given 0.5 ms timing resolution. The main burst arises from the peak luminosity before the merger. The post-merger burst follows from the NS magnetic field migration to the BH, causing a shock. NS–BH pairs are especially desirable for ground-based gravitational wave (GW) observatories since the pair might not otherwise be detected, with EM counterparts greatly augmenting the scientific leverage beyond the GW signal. The EM signal’s ability to break degeneracies in the parameters encoded in the GW and probe the NS magnetic field strength is quite valuable, yielding insights into open problems in NS magnetic field decay

  2. Gamma-ray bursts

    CERN Document Server

    Wijers, Ralph A M J; Woosley, Stan

    2012-01-01

    Cosmic gamma ray bursts (GRBs) have fascinated scientists and the public alike since their discovery in the late 1960s. Their story is told here by some of the scientists who participated in their discovery and, after many decades of false starts, solved the problem of their origin. Fourteen chapters by active researchers in the field present a detailed history of the discovery, a comprehensive theoretical description of GRB central engine and emission models, a discussion of GRB host galaxies and a guide to how GRBs can be used as cosmological tools. Observations are grouped into three sets from the satellites CGRO, BeppoSAX and Swift, and followed by a discussion of multi-wavelength observations. This is the first edited volume on GRB astrophysics that presents a fully comprehensive review of the subject. Utilizing the latest research, Gamma-ray Bursts is an essential desktop companion for graduate students and researchers in astrophysics.

  3. Elementary particle physics and high energy phenomena

    International Nuclear Information System (INIS)

    Barker, A.R.; Cumalat, J.P.; De Alwis, S.P.; DeGrand, T.A.; Ford, W.T.; Mahanthappa, K.T.; Nauenberg, U.; Rankin, P.; Smith, J.G.

    1992-06-01

    Experimental and theoretical high-energy physics programs at the University of Colorado are reported. Areas of concentration include the following: study of the properties of the Z 0 with the SLD detector; fixed-target K-decay experiments; the R ampersand D program for the muon system: the SDC detector; high-energy photoproduction of states containing heavy quarks; electron--positron physics with the CLEO II detector at CESR; lattice QCD; and spin models and dynamically triangulated random surfaces. 24 figs., 2 tabs., 117 refs

  4. High energy physics computing in Japan

    International Nuclear Information System (INIS)

    Watase, Yoshiyuki

    1989-01-01

    A brief overview of the computing provision for high energy physics in Japan is presented. Most of the computing power for high energy physics is concentrated in KEK. Here there are two large scale systems: one providing a general computing service including vector processing and the other dedicated to TRISTAN experiments. Each university group has a smaller sized mainframe or VAX system to facilitate both their local computing needs and the remote use of the KEK computers through a network. The large computer system for the TRISTAN experiments is described. An overview of a prospective future large facility is also given. (orig.)

  5. Fast Radio Bursts with Extended Gamma-Ray Emission?

    International Nuclear Information System (INIS)

    Murase, Kohta; Mészáros, Peter; Fox, Derek B.

    2017-01-01

    We consider some general implications of bright γ -ray counterparts to fast radio bursts (FRBs). We show that even if these manifest in only a fraction of FRBs, γ -ray detections with current satellites (including Swift ) can provide stringent constraints on cosmological FRB models. If the energy is drawn from the magnetic energy of a compact object such as a magnetized neutron star, the sources should be nearby and be very rare. If the intergalactic medium is responsible for the observed dispersion measure, the required γ -ray energy is comparable to that of the early afterglow or extended emission of short γ -ray bursts. While this can be reconciled with the rotation energy of compact objects, as expected in many merger scenarios, the prompt outflow that yields the γ -rays is too dense for radio waves to escape. Highly relativistic winds launched in a precursor phase, and forming a wind bubble, may avoid the scattering and absorption limits and could yield FRB emission. Largely independent of source models, we show that detectable radio afterglow emission from γ -ray bright FRBs can reasonably be anticipated. Gravitational wave searches can also be expected to provide useful tests.

  6. Scientific Applications Performance Evaluation on Burst Buffer

    KAUST Repository

    Markomanolis, George S.

    2017-10-19

    Parallel I/O is an integral component of modern high performance computing, especially in storing and processing very large datasets, such as the case of seismic imaging, CFD, combustion and weather modeling. The storage hierarchy includes nowadays additional layers, the latest being the usage of SSD-based storage as a Burst Buffer for I/O acceleration. We present an in-depth analysis on how to use Burst Buffer for specific cases and how the internal MPI I/O aggregators operate according to the options that the user provides during his job submission. We analyze the performance of a range of I/O intensive scientific applications, at various scales on a large installation of Lustre parallel file system compared to an SSD-based Burst Buffer. Our results show a performance improvement over Lustre when using Burst Buffer. Moreover, we show results from a data hierarchy library which indicate that the standard I/O approaches are not enough to get the expected performance from this technology. The performance gain on the total execution time of the studied applications is between 1.16 and 3 times compared to Lustre. One of the test cases achieved an impressive I/O throughput of 900 GB/s on Burst Buffer.

  7. Progress in high-energy laser technology

    International Nuclear Information System (INIS)

    Miyanaga, Noriaki; Kitagawa, Yoneyoshi; Nakatsuka, Masahiro; Kanabe, Tadashi; Okuda, Isao

    2005-01-01

    The technological development of high-energy lasers is one of the key issues in laser fusion research. This paper reviews several technologies on the Nd:glass laser and KrF excimer laser that are being used in the current laser fusion experiments and related plasma experiments. Based on the GEKKO laser technology, a new high-energy Nd: glass laser system, which can deliver energy from 10 kJ (boad-band operation) to 20 kJ (narrow-band operation), is under construction. The key topics in KrF laser development are improved efficiency and repetitive operation, which aim at the development of a laser driven for fusion reactor. Ultra-intense-laser technology is also very important for fast ignition research. The key technology for obtaining the petawatt output with high beam quality is reviewed. Regarding the uniform laser irradiation required for high-density compression, the beam-smoothing methods on the GEKKO XII laser are reviewed. Finally, we discuss the present status of MJ-class lasers throughout the world, and summarize by presenting the feasibility of various applications of the high-energy lasers to a wide range of scientific and technological fields. (author)

  8. High Tc superconducting energy storage systems

    Energy Technology Data Exchange (ETDEWEB)

    Werfel, Frank [Adelwitz Technologiezentrum GmbH (ATZ), Arzberg-Adelwitz (Germany)

    2012-07-01

    Electric energy is basic to heat and light our homes, to power our businesses and to transport people and goods. Powerful storage techniques like SMES, Flywheel, Super Capacitor, and Redox - Flow batteries are needed to increase the overall efficiency, stability and quality of electrical grids. High-Tc superconductors (HTS) possess superior physical and technical properties and can contribute in reducing the dissipation and losses in electric machines as motors and generators, in electric grids and transportation. The renewable energy sources as solar, wind energy and biomass will require energy storage systems even more as a key technology. We survey the physics and the technology status of superconducting flywheel energy storage (FESS) and magnetic energy storage systems (SMES) for their potential of large-scale commercialization. We report about a 10 kWh / 250 kW flywheel with magnetic stabilization of the rotor. The progress of HTS conductor science and technological engineering are basic for larger SMES developments. The performance of superconducting storage systems is reviewed and compared. We conclude that a broad range of intensive research and development in energy storage is urgently needed to produce technological options that can allow both climate stabilization and economic development.

  9. A new method for calculating energy release rate in tunnel excavation subjected to high in situ stress

    Directory of Open Access Journals (Sweden)

    Xiao Qinghua

    2016-03-01

    Full Text Available Based on energy theory, energy release rate (EER and local energy release rate (LEER, a new index called FERR (Fractional Energy Release Rate is proposed, and this method can not only evaluate the risk of rock burst, but also can point out the location of high risk and the scale of rockburst. The FERR index is applied to the TBM assembling tunnel in Jinping Hydro Power Station II to evaluate the scale and intensity of rockburst, as well as the location where rockburst occurs. With FDM method adopted, the energy release rate of 3 excavation plans are calculated and the scale and risk of rockburst is evaluated, and the location of high risk of rockburst is also mapped. With FERR used in the evaluation, the rockburst is nicely controlled which ensured the safety and construction schedule of the project.

  10. Baryon number violation in high energy collisions

    International Nuclear Information System (INIS)

    Farrar, G.R.; Meng, R.

    1990-08-01

    We study the phenomenology of baryon number violation induced by electroweak instantons. We find that if the naive-instanton amplitudes were valid for arbitrarily high energies, the event rate at the SSC would be a few per hour, with a typical event consisting of 3 'primary' antileptons and 7 'primary' antiquark jets, accompanied by ≅ 85 electroweak gauge bosons, having a sharp threshold in the total sub-energy at about 17 TeV. We describe how to establish their electroweak-instanton-induced origin. The naive instanton approximation is known to overestimate the rate for these processes, so this work focusses attention on the need for more accurate calculations, and for a calculational method which is appropriate when the energy of the initial particles is above the sphaleron energy. (orig.)

  11. The development of a burst criterion for zircaloy fuel cladding under LOCA conditions

    International Nuclear Information System (INIS)

    Neitzel, H.J.; Rossinger, H.E.

    1980-02-01

    A burst criterion model, which assumes that deformation is controlled by steady-state creep, has been developed for a thin-walled cladding, in this case Zircaloy-4, subjected to a differential pressure and high temperature. The creep equation is integrated to obtain a burst time at the singularity of the strain. Once the burst time is known, the burst temperature and burst pressure can be calculated from the known temperature and pressure histories. A further relationship between burst stress and burst temperature is used to calculate the burst strain. Comparison with measured burst data shows good agreement between theory and experiment was found that, if the heating rate is constant, the burst temperature increases with decreasing stress, and that, if the stress level is constant, the burst temperature increases with increasing heating rate. It was also found that anisotropy alters the burst temperature and burst strain, and that test conditions in the α-Zr temperature range have no influence on the burst data. (auth)

  12. GRB 110205A: ANATOMY OF A LONG GAMMA-RAY BURST

    International Nuclear Information System (INIS)

    Gendre, B.; Stratta, G.; Atteia, J. L.; Klotz, A.; Boër, M.; Colas, F.; Vachier, F.; Kugel, F.; Rinner, C.; Laas-Bourez, M.; Strajnic, J.

    2012-01-01

    The Swift burst GRB 110205A was a very bright burst visible in the Northern Hemisphere. GRB 110205A was intrinsically long and very energetic and it occurred in a low-density interstellar medium environment, leading to delayed afterglow emission and a clear temporal separation of the main emitting components: prompt emission, reverse shock, and forward shock. Our observations show several remarkable features of GRB 110205A: the detection of prompt optical emission strongly correlated with the Burst Alert Telescope light curve, with no temporal lag between the two; the absence of correlation of the X-ray emission compared to the optical and high-energy gamma-ray ones during the prompt phase; and a large optical re-brightening after the end of the prompt phase, that we interpret as a signature of the reverse shock. Beyond the pedagogical value offered by the excellent multi-wavelength coverage of a gamma-ray burst with temporally separated radiating components, we discuss several questions raised by our observations: the nature of the prompt optical emission and the spectral evolution of the prompt emission at high energies (from 0.5 keV to 150 keV); the origin of an X-ray flare at the beginning of the forward shock; and the modeling of the afterglow, including the reverse shock, in the framework of the classical fireball model.

  13. Application of nanotechnologies in high energy physics

    International Nuclear Information System (INIS)

    Angelucci, R.; Corticelli, F.; Cuffiani, M.; Dallavalle, G.M.; Malferraxi, L.; Montanari, A.; Montanari, C.; Odorici, F.; Rizzoli, R.; Summonte, C.

    2003-01-01

    In the past, the progressive reduction of electronics integration scale has allowed high energy physics experiments to build particle detectors with a high number of sensitive channels and high spatial granularity, down to the micron scale. Nowadays, the increasing effort towards nanoelectronics and progresses in various fields of nanotechnologies, suggests that the time for nanodetectors is not far to come. As an example of possible application of nanotechnologies in HEP, we present results on fabrication of nanochannel matrices in anodic porous alumina as a template for preparing an array of carbon nanotubes, which we believe can be a promising building block in developing particle detectors with high spatial resolution

  14. 22nd DAE High Energy Physics Symposium

    CERN Document Server

    2018-01-01

    These proceedings gather invited and contributed talks presented at the XXII DAE-BRNS High Energy Physics (HEP) Symposium, which was held at the University of Delhi, India, on 12–16 December 2016. The contributions cover a variety of topics in particle physics, astroparticle physics, cosmology and related areas from both experimental and theoretical perspectives, namely (1) Neutrino Physics, (2) Standard Model Physics (including Electroweak, Flavour Physics), (3) Beyond Standard Model Physics, (4) Heavy Ion Physics & QCD (Quantum Chromodynamics), (5) Particle Astrophysics & Cosmology, (6) Future Experiments and Detector Development, (7) Formal Theory, and (8) Societal Applications: Medical Physics, Imaging, etc. The DAE-BRNS High Energy Physics Symposium, widely considered to be one of the leading symposiums in the field of Elementary Particle Physics, is held every other year in India and supported by the Board of Research in Nuclear Sciences (BRNS), Department of Atomic Energy (DAE), India. As man...

  15. Photodisintegration of the deuteron at high energy

    International Nuclear Information System (INIS)

    Holt, R.J.

    1992-01-01

    Measurements of the angular distribution for the γd→+pn reaction were performed at SLAC for photon energies between 0.7 and 1.8 GeV (experiment NE8) and between 1.6 and 4.4. GeV (experiment NE17). The final results for experiment NE8 will be presented, but only preliminary results for NE17 will be discussed. The data at θ cm = 90 degrees appear to follow the constituent counting rules. The angular distribution at high photon energies exhibit large values of the cross section at forward angles. There is evidence that the cross section may also be large at backward angles and high energies

  16. Advanced communications technology satellite high burst rate link evaluation terminal power control and rain fade software test plan, version 1.0

    Science.gov (United States)

    Reinhart, Richard C.

    1993-01-01

    The Power Control and Rain Fade Software was developed at the NASA Lewis Research Center to support the Advanced Communications Technology Satellite High Burst Rate Link Evaluation Terminal (ACTS HBR-LET). The HBR-LET is an experimenters terminal to communicate with the ACTS for various experiments by government, university, and industry agencies. The Power Control and Rain Fade Software is one segment of the Control and Performance Monitor (C&PM) Software system of the HBR-LET. The Power Control and Rain Fade Software automatically controls the LET uplink power to compensate for signal fades. Besides power augmentation, the C&PM Software system is also responsible for instrument control during HBR-LET experiments, control of the Intermediate Frequency Switch Matrix on board the ACTS to yield a desired path through the spacecraft payload, and data display. The Power Control and Rain Fade Software User's Guide, Version 1.0 outlines the commands and procedures to install and operate the Power Control and Rain Fade Software. The Power Control and Rain Fade Software Maintenance Manual, Version 1.0 is a programmer's guide to the Power Control and Rain Fade Software. This manual details the current implementation of the software from a technical perspective. Included is an overview of the Power Control and Rain Fade Software, computer algorithms, format representations, and computer hardware configuration. The Power Control and Rain Fade Test Plan provides a step-by-step procedure to verify the operation of the software using a predetermined signal fade event. The Test Plan also provides a means to demonstrate the capability of the software.

  17. Diverse Long-term Variability of Five Candidate High-mass X-Ray Binaries from Swift Burst Alert Telescope Observations

    Energy Technology Data Exchange (ETDEWEB)

    Corbet, Robin H. D. [University of Maryland, Baltimore County, MD 21250 (United States); Coley, Joel B. [NASA Postdoctoral Program, and Astroparticle Physics Laboratory, Code 661 NASA Goddard Space Flight Center, Greenbelt Road, MD 20771 (United States); Krimm, Hans A., E-mail: corbet@umbc.edu [Universities Space Research Association, 10211 Wincopin Circle, Suite 500, Columbia, MD 21044 (United States)

    2017-09-10

    We present an investigation of long-term modulation in the X-ray light curves of five little-studied candidate high-mass X-ray binaries using the Swift Burst Alert Telescope. IGR J14488-5942 and AX J1700.2-4220 show strong modulation at periods of 49.6 and 44 days, respectively, which are interpreted as orbital periods of Be star systems. For IGR J14488-5942, observations with the Swift X-ray Telescope show a hint of pulsations at 33.4 s. For AX J1700.2-4220, 54 s pulsations were previously found with XMM-Newton . Swift J1816.7-1613 exhibits complicated behavior. The strongest peak in the power spectrum is at a period near 150 days, but this conflicts with a determination of a period of 118.5 days by La Parola et al. AX J1820.5-1434 has been proposed to exhibit modulation near 54 days, but the extended BAT observations suggest modulation at slightly longer than double this at approximately 111 days. There appears to be a long-term change in the shape of the modulation near 111 days, which may explain the apparent discrepancy. The X-ray pulsar XTE J1906+090, which was previously proposed to be a Be star system with an orbital period of ∼30 days from pulse timing, shows peaks in the power spectrum at 81 and 173 days. The origins of these periods are unclear, although they might be the orbital period and a superorbital period respectively. For all five sources, the long-term variability, together with the combination of orbital and proposed pulse periods, suggests that the sources contain Be star mass donors.

  18. Effects of High Frequency Repeated Transcranial Magnetic Stimulation and Continuous Theta Burst Stimulation on Gambling Reinforcement, Delay Discounting, and Stroop Interference in Men with Pathological Gambling.

    Science.gov (United States)

    Zack, Martin; Cho, Sang Soo; Parlee, Jennifer; Jacobs, Mark; Li, Crystal; Boileau, Isabelle; Strafella, Antonio

    Repeated transcranial magnetic stimulation (rTMS) can reduce cravings and improve cognitive function in substance dependent individuals. Whether these benefits extend to individuals with pathological gambling (PG) is unclear. High-frequency rTMS of the medial prefrontal cortex (PFC) and continuous theta burst stimulation (cTBS) of the right dorsolateral PFC can reduce impulsive choice in healthy volunteers. This study aimed to assess the effects of these two protocols on gambling reinforcement and related responses in otherwise healthy men with PG. Participants (n = 9) underwent active or sham treatments at weekly intervals in a repeated-measures, Latin square design. Subjective and physiological responses were assessed before and after a 15-min slot machine game on each session. Delay discounting and Stroop tasks measured post-game impulsive choice and attentional control. Multivariate analysis of covariance, controlling for winnings on the slot machine under each treatment, found that rTMS reduced the post-game increase in Desire to Gamble; cTBS reduced amphetamine-like effects, and decreased diastolic blood pressure. Treatment had no significant univariate effects on bet size or speed of play in the game; however, a multivariate effect for the two indices suggested that treatment decreased behavioral activation. Neither treatment reduced impulsive choice, while both treatments increased Stroop interference. rTMS and cTBS can reduce gambling reinforcement in non-comorbid men with PG. Separate processes appear to mediate gambling reinforcement and betting behavior as against delay discounting and Stroop interference. Interventions that modify risky as opposed to temporal aspects of decision making may better predict therapeutic response in PG. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Observation of Galactic Sources of Very High Energy γ-RAYS with the Magic Telescope

    Science.gov (United States)

    Bartko, H.

    The MAGIC telescope with its 17m diameter mirror is today the largest operating single-dish Imaging Air Cherenkov Telescope (IACT). It is located on the Canary Island La Palma, at an altitude of 2200 m above sea level, as part of the Roque de los Muchachos European Northern Observatory. The MAGIC telescope detects celestial very high energy γ-radiation in the energy band between about 50 GeV and 10 TeV. Since the autumn of 2004 MAGIC has been taking data routinely, observing various objects, like supernova remnants (SNRs), γ-ray binaries, Pulsars, Active Galactic Nuclei (AGN) and Gamma-ray Bursts (GRB). We briefly describe the observational strategy, the procedure implemented for the data analysis, and discuss the results of observations of Galactic Sources.

  20. High energy excitations in itinerant ferromagnets

    International Nuclear Information System (INIS)

    Prange, R.E.

    1984-01-01

    Itinerant magnets, those whose electrons move throughout the crystal, are described by band theory. Single particle excitations offer confirmation of band theory, but their description requires important corrections. The energetics of magnetism in iron and nickel is also described in band theory but requires complex bands. Magnetism above the critical temperature and the location of the critical temperature offer discriminants between the two major models of magnetism at high temperature and can be addressed by high energy excitations