Energy Spectrum Of Primary Cosmic Rays Research Articles

Primary cosmic-ray energy spectrum around the knee energy region measured by the Tibet hybrid experiment

The Tibet hybrid experiment composed of emulsion chambers, burst detectors and the Tibet-II air-shower array was done at Yangbajing (4,300m above sea level, 606 g/cm2) in Tibet. For 3-year operation, we have observed 177 γ-families (ΣEγ > 20 TeV) accompanying air showers with the shower size Ne > 2 × 105. Using this data set and a neural network method to select proton and helium induced events, the primary proton and helium energy spectra are deduced between 1015 and 1016eV. The proton spectrum, thus obtained, can be expressed by a single power-law function with a differential index of −3.01±0.11 and −3.05±0.12 based on the QGSJET+HD and SIBYLL+HD models, respectively, which are steeper than that extrapolated from the direct observations of −2.74±0.01 in the energy range below 1014 eV. Our result suggests that the main component responsible for making the knee structure of the all-particle spectrum should be composed of nuclei heavier than helium.

UNDERGROUND MUON ENERGY SPECTRA WITH THE MACRO TRD

The MACRO detector was located in the Hall B of the Gran Sasso underground Laboratories under an average rock overburden of 3700 hg/cm2. A TRD composed by three identical modules, covering an horizontal area of 36 m2, was added to the MACRO detector in order to measure the residual energy of muons entering MACRO. This kind of measurement provides a useful tool to study the primary cosmic ray energy spectra and composition, their interactions with the Earth's atmosphere and the propagation of muons inside the rock. The results of the measurement of the energy of single and double muons crossing MACRO will be presented. Our data show that double muons are more energetic than single ones in the rock depth range from 3000 to 6500 hg/cm2. Single muon data confirm the reliability of the models adopted to describe the cosmic ray interactions with the atmosphere and the muon propagation inside the rock.

Cutoff of primary cosmic ray energy spectrum without the knee and the ankle

Experimental and theoretical situation in investigations of cosmic rays with energies higher than the knee is considered. The evidences of new state of matter production in interactions of PeV cosmic rays are analysed. Theoretical model of cosmic ray acceleration in cosmic plasma pinches with constant slope of energy spectrum γ = 3 is described. Consequences for future experiments and for interpretation of their results around the cutoff are discussed.

Energy spectrum and elemental composition of cosmic rays in the PeV region

KASCADE (KArlsruhe Shower Core and Array DEtector) is determining flux spectra for different primary mass groups to disentangle the knee feature of the primary cosmic-ray energy spectrum. The energy spectra of the light element groups result in a knee-like bending and a steepening above the knee. The topology of the individual knee positions suggests a rigidity dependence. To proof the rigidity dependence the KASCADE array is now extended by a factor 10 in area. The major goal of KASCADE-Grande is the observation of the ’iron-knee’ in the cosmic-ray spectrum at around 100 PeV which is expected following the KASCADE observations. PACS: 98.70.Sa Cosmic rays

The ATIC long duration balloon project

Long Duration Balloon (LDB) scientific experiments, launched to circumnavigate the south pole over Antarctica, have particular advantages compared to Shuttle or other Low Earth Orbit (LEO) missions in terms of cost, weight, scientific “duty factor” and work force development. The Advanced Thin Ionization Calorimeter (ATIC) cosmic-ray astrophysics experiment is a good example of a university-based project that takes full advantage of current LDB capability. The ATIC experiment is currently being prepared for its first LDB science flight that will investigate the charge composition and energy spectra of primary cosmic-rays over the energy range from about 10 10 to 10 14 eV. The instrument is built around a fully active, Bismuth–Germanate (BGO) ionization calorimeter to measure the energy deposited by cascades formed by particles interacting in a thick carbon target. A highly segmented silicon matrix, located above the target, provides good incident charge resolution plus rejection of “backscattered” particles from the cascade. Trajectory reconstruction is based on the cascade profile in the BGO calorimeter, plus information from the three pairs of scintillator hodoscope layers in the target section above it. A full evaluation of the experiment was performed during a test flight occurring between 28 December 2000 and 13 January 2001 where ATIC was carried to an altitude of ∼37 km above Antarctica by a ∼850,000 m 3 helium filled balloon for one circumnavigation of the continent. All systems behaved well, the detectors performed as expected, >43 GB of engineering and cosmic-ray event data were returned and these data are now undergoing preliminary data analysis. During the coming 2002–2003 Antarctica summer season, we are preparing for an ATIC science flight with ∼15 to 30 days of data collection in the near-space environment of Long Duration Balloon (LDB) float altitudes.

The ATIC long duration balloon project

Long Duration Balloon (LDB) scientific experiments, launched to circumnavigate the south pole over Antarctica, have particular advantages compared to Shuttle or other Low Earth Orbit (LEO) missions in terms of cost, weight, scientific “duty factor” and work force development. The Advanced Thin Ionization Calorimeter (ATIC) cosmic-ray astrophysics experiment is a good example of a university-based project that takes full advantage of current LDB capability. The ATIC experiment is currently being prepared for its first LDB science flight that will investigate the charge composition and energy spectra of primary cosmic-rays over the energy range from about 10 10 to 10 14 eV. The instrument is built around a fully active, Bismuth–Germanate (BGO) ionization calorimeter to measure the energy deposited by cascades formed by particles interacting in a thick carbon target. A highly segmented silicon matrix, located above the target, provides good incident charge resolution plus rejection of “backscattered” particles from the cascade. Trajectory reconstruction is based on the cascade profile in the BGO calorimeter, plus information from the three pairs of scintillator hodoscope layers in the target section above it. A full evaluation of the experiment was performed during a test flight occurring between 28 December 2000 and 13 January 2001 where ATIC was carried to an altitude of ∼37 km above Antarctica by a ∼850,000 m 3 helium filled balloon for one circumnavigation of the continent. All systems behaved well, the detectors performed as expected, >43 GB of engineering and cosmic-ray event data were returned and these data are now undergoing preliminary data analysis. During the coming 2002–2003 Antarctica summer season, we are preparing for an ATIC science flight with ∼15 to 30 days of data collection in the near-space environment of Long Duration Balloon (LDB) float altitudes.

Pulsar PSR B0656+14, the Monogem Ring, and the Origin of the "Knee" in the Primary Cosmic-Ray Spectrum

The Monogem ring is a bright, diffuse, 25° diameter supernova remnant easily visible in soft X-ray images of the sky. Projected within the ring is a young radio pulsar, PSR B0656+14. An association between the remnant and pulsar has been considered but was seemingly ruled out by the direction and magnitude of the pulsar proper motion and by a distance estimate that placed the pulsar twice as far from Earth as the remnant. Here we show that in fact the pulsar was born very close to the center of the expanding remnant, both in distance and in projection. The inferred pulsar and remnant ages are in good agreement. The conclusion that the pulsar and remnant were born in the same supernova explosion is nearly inescapable. The remnant distance and age are in remarkable concordance with the predictions of a model for the primary cosmic-ray energy spectrum in which the knee feature is produced by a single dominant source.

High-energy gamma rays from the ‘single source’ of the knee

Recently, Erlykin and Wolfendale (Erlykin A D and Wolfendale A W 1997 J. Phys. G: Nucl. Part. Phys. 23 979) have proposed a ‘single source’ model of cosmic rays in which an explosion of a single, nearby and recent supernova is responsible for the ‘knee’ structure of the primary cosmic ray energy spectrum. In this paper, we discuss some estimates of the flux of gamma rays to be observed on the Earth from the proposed ‘single source’ of the knee. When compared with the observation, it appears that the single source, if it exists, is unlikely to be a supernova remnant.

Muon density measurements with the KASCADE central detector

Frequency distributions of local muon densities in high-energy extensive air showers (EAS) are presented as signature of the primary cosmic ray energy spectrum in the knee region. Together with the gross shower variables like shower core position, angle of incidence, and the shower sizes, the KASCADE experiment is able to measure local muon densities for two different muon energy thresholds. The spectra have been reconstructed for various core distances, as well as for particular subsamples, classified on the basis of the shower size ratio N μ/ N e. The measured density spectra of the total sample exhibit clear kinks reflecting the knee of the primary energy spectrum. While relatively sharp changes of the slopes are observed in the spectrum of EAS with small values of the shower size ratio, no such feature is detected at EAS of large N μ/ N e ratio in the energy range of 1–10 PeV. Comparing the spectra for various thresholds and core distances with detailed Monte Carlo simulations the validity of EAS simulations is discussed.

The new Tien-Shan Atmospheric Čerenkov Telescope (TACT). Contemporary status: all-particle spectrum measured

Abstract Results for the primary cosmic ray energy spectrum at 100–1000 TeV, data on the lateral distribution function for Cerenkov light of EAS and curvature of Cerenkov photon front are presented. Measurements were carried out using an array for observation of discrete gamma-sources in the TeV region.

Around and above the knee

Problems related to the origin of the knee in the PeV region of the primary cosmic ray energy spectrum are discussed. The most important ones among them are the shape of spectra for different cosmic ray components at different atmospheric depths, and the variation of the mass composition with primary energy. The knee is a complicated phenomenon, and simple models seem unable to explain its origin.

Camera obscura for observation of EAS in Cerenkov light

A new instrument, a camera obscura with a number of light apertures (or slits), is suggested for observation of EAS images in Cerenkov light. Its advantages (over mirror-imaging telescopes) are a low night-sky light noise, a wide field of view and absence of aberrations. This camera is effective for measurements of bright objects such as EAS of energies higher than 103 TeV. Analysis of EAS images in the 'knee' region of the primary cosmic-ray energy spectrum (E0 approximately=3*103 TeV) could give new information on the expected variation of cosmic-ray composition in this energy region.

Akeno Giant Air Shower Array (AGASA) covering 100 km 2 area

A very large surface array has been constructed recently at Akeno, 120 km west of Tokyo, to study the spectral features of the primary cosmic ray energy spectrum at the highest energies and to search for discrete sources emitting cosmic rays at energies above 10 17 eV. The new array, AGASA (Akeno Giant Air Shower Array) spread over an area of about 100 km 2, consists of 111 scintillation detectors, each 2.2 m 2 in area and 27 muon detectors of six different sizes. The distance between the detectors is about 1 km. The data acquisition network developed for AGASA links detectors with each other and with the four branch controllers with two optical-fiber cables for all communications. We present here the salient design features of AGASA and discuss the estimates of the accuracy in the determination of arrival direction and primary energy of showers expected to be achieved with AGASA.

The Knee of the Cosmic Ray Energy Spectrum

An examination is made of possible primary cosmic ray energy spectra which are consistent with observed air shower size spectra. At the size spectrum knee, it is necessary to have a very sharp primary spectrum break in order to be consistent with both the size spectrum and also air shower ftuctuations. Such a break may be due to energy loss at the cosmic ray source.

Sea Level Muon Spectrum Derived from Bugaev Model Using the Primary Cosmic Ray Energy Spectrum of Grigorov et al

AbstractIn a recent paper BHATTACHARYYA has derived the pion and kaon production spectra in the atmosphere using a form of the primary nucleon energy spectrum of the measurements of GRIGOROV et al. and the interaction model of BUGAEV et al. The sea level muon spectrum derived from these meson spectra agrees with the magnetic spectrograph data of ALLKOFER et al. and AYRE et al.In this report a critical analysis of the paper has been made and some obvious mistakes in the formulation have been pointed out. The formulation of BUGAEV et al. and the data of GRIGOROV at al. have been misinterpreted by BHATTACHARYYA. The corrected results have been properly interpreted in this report.

Abundances and spectra for cosmic-ray nuclei from lithium to iron for 2 to 150 GeV per nucleon

view Abstract Citations (90) References (54) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Abundances and spectra for cosmic-ray nuclei from lithium to iron for 2 to 150 GeV per nucleon. Orth, C. D. ; Buffington, A. ; Smoot, G. F. ; Mast, T. S. Abstract Measurements of primary cosmic-ray composition and energy spectra made with a balloon-borne superconducting magnetic spectrometer are described. Results for both 6.7 g/sq cm equivalent vertical atmospheric depth and the top of the atmosphere are presented for the absolute and relative integral abundances, the differential energy spectra, and the spectral indices for cosmic-ray nuclei from Li to Fe and energies of 2 to 50 GeV/n. It is found that propagation effects can explain essentially all the elemental abundances, that the abundances of Li, Be, and B for rigidities below 10 GV/c are consistent with an energy-independent mean interstellar path length of 4.5 + or - 0.5 g/sq cm for the 'leaky box' propagation model, that the abundances of all elements above 10 GV/c are consistent with a path length that decreases as the inverse n-th power of rigidity, and that n equals 0.6 (+0.4, -0.3) for the simplest assumptions made in fitting the source spectra. Publication: The Astrophysical Journal Pub Date: December 1978 DOI: 10.1086/156692 Bibcode: 1978ApJ...226.1147O Keywords: Abundance; Energy Spectra; Particle Energy; Primary Cosmic Rays; Astronomical Models; Balloon-Borne Instruments; Data Reduction; Electric Charge; Instrument Errors; Propagation; Superconducting Magnets; Space Radiation; Cosmic Rays:Element Abundances full text sources ADS |

A model for the break in the primary cosmic-ray energy spectrum at ∼1015 eV

A model for the break in the primary cosmic-ray energy spectrum at ∼1015 eV

Primary Cosmic-Ray Electron Energy Spectrum from 10 to 200 MeV Observed in Interplanetary Space

Quiet time primary cosmic ray electron flux and energy spectrum from 10 to 200 Mev in interplanetary space observed by OGO 5 satellite

The energy-loss spectrum of extensive air showers recorded by the Haverah Park 500 m array

An integral energy-loss spectrum of air showers is presented for each of four zenith angle intervals 0 degrees -20 degrees , 20 degrees -30 degrees on 2950 showers selected from over 30 000 recorded by the Haverah Park 500m air shower array in a running time of 6.4*107s. Here the energy loss of a shower is defined as the energy dissipated by the shower in an annulus of water 1.2 m thick in the range of distance 100 m to 1000 m from the shower axis. The energy-loss spectra for the four zenith angle intervals may be represented by power laws of exponent -1.94+or-0.06, -2.10+or-0.06, -2.26+or-0.09 and -2.22+or-0.10, respectively, over the energy-loss range 1014.6-1015.6 eV. This corresponds, in so far as the relation between energy loss and primary energy has been established to primary energies in the range 1017-1018 ev. The zenith angle distribution of the selected showers is consistent with exponential atmospheric absorption with an absorption length of 150+or-5 g cm-2. The results show no indication of a change in the slope of the primary cosmic ray energy spectrum within the energy range 1017- 1018 ev.

The composition of low-energy cosmic rays in 1965

Primary cosmic-ray energy spectra and charge composition have been measured during the 1965 period of solar modulation minimum. A dE/dx vs. E type of scintillator–photomultiplier detector on board the eccentric-orbiting NASA spacecraft OGO-I was used. The charge composition was measured through neon over an energy range of 25 to 200 MeV/nucleon, depending upon the specific component. The spectra for all groups are nearly flat during this time, with the oxygen flux at about 0.005 nucleus/(M2-sr-s-MeV/nucleon). The relative abundances found are Li, 0.27; Be, 0.11; B, 0.37; C, 1.20; N, 0.30; O 1.00; F, [Formula: see text]; Ne, 0 12 An L/M ratio of 0.30 ± 0.06 is found.