Energy Spectrum Of Primary Cosmic Rays Research Articles

Tokyo large air shower project

A preliminary experiment to detect large air showers by means of radio echoes and to study the high-energy end of the primary cosmic-ray energy spectrum has been started at this Institute. The fundamental idea and the first approach of the experiment are presented. Using the telemetry system between two pairs of a simple scintillation array, which has been constructed to identify and calibrate the showers in the above experiment, the decoherence curve of air showers has been measured between 100 and 1 300 m together with the particle density in each detector. This simple experiment will give the power of the size spectrum above 109.

The Primary Cosmic-Ray Electron Energy Spectrum from 10 TO 40 Mev

view Abstract Citations (10) References (6) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Primary Cosmic-Ray Electron Energy Spectrum from 10 TO 40 Mev Fan, C. Y. ; Gloeckler, G. ; Simpson, J. A. ; Verma, S. D. Abstract The differential energy spectrum of primary cosmic ray electrons in the energy range 10 - 40 MeV was measured on the IMP-ITT satellite during the period of minimum solar modulation for galactic cosmic rays. The average flux was found to be 3 ± 2 electrons/(m2 sec sterad MeV) and the differential energy spectrum joins previous measurements made at lower and higher energies Publication: The Astrophysical Journal Pub Date: February 1968 DOI: 10.1086/149471 Bibcode: 1968ApJ...151..737F full text sources ADS |

The Primary Cosmic-Ray Electron Spectrum Near Solar Minimum

view Abstract Citations (40) References (26) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Primary Cosmic-Ray Electron Spectrum Near Solar Minimum L'Heureux, Jacques Abstract Two balloon flights were made from Fort Churchill, Manitoba, in the summer of 1965 to continue our investigation of the flux and energy spectrum of the primary cosmic-ray electron component. The spectrum was studied for energies from 20 MeV to 5.5 BeV. Above 1.2 BeV, the differential energy spectrum can be represented by a power la of the form dJ/dE = (48 + 15)E-(2 110 3) electrons . For energies below 1 BeV the spectrum becomes flatter (slope <= 1.6). Between 20 and 270 MeV the total flux rather than the differential flux has been measured. Its value is 180 + 30 electrons . A comparison of our results with data at higher energies obtained by other authors indicates that the spectrum is steeper above 10 BeV ( = 2.45). Our data are also compared with the results obtained from the observations of the non-thermal radio emission from high galactic latitudes. The electron energy spectrum obtained in this experiment is, for energies greater than 1 BeV, in agreement with the spectrum of galactic electrons as derived from the radio-noise measurements. Below 1 BeV the measured electron energy spectrum is flatter than would be predicted on the basis of the radio-noise frequency spectrum for frequencies less than 50 Mc/s (corresponding to electrons below 1 BeV). This might be an indication that solar modulation, even near solar minimum, affects the electron spectrum measured at Earth. The measurements were carried out using a counter system A total-absorbtion lead-glass Cerenkov counter was used to obtain the energy of the electrons Low-energy protons were rejected by the use of a gas (erenkov threshold counter. Guard counters served to identify high-energy protons. Publication: The Astrophysical Journal Pub Date: May 1967 DOI: 10.1086/149162 Bibcode: 1967ApJ...148..399L full text sources ADS |

Energy Spectrum of Primary Cosmic-Rays

Energy Spectrum of Primary Cosmic-Rays

The multiply charged primary cosmic radiation at solar minimum, 1965

Primary cosmic ray charge and energy spectra for helium through oxygen during 1965 minimum solar modulation effect

The density spectrum of air showers at sea level and mountain altitudes

The cosmic-ray differential density spectrum in the range 3 to 10000 p/m2 has been obtained, using Wilson cloud chambers, at sea level and at 2285 m a.s.l. In neither case can the whole spectrum be fitted by a single power law. Using a three-parameter fit the sea-level spectrum is best approximated by two power laws of exponents − 2.491±0.036 and −3.42±0.32, respectively, joining at 560± 180 particles per square metre. At 2285 m a.s.l. the three best parameters are − 2.431 ±0.015, − 4.8−0.8+1.3 and 6000−800+1000 particles per square metre. The change with altitude supports the hypothesis that the change in exponent is due to a steepening of the primary cosmic-ray energy spectrum.

Cosmic ray measurements in the U.K. Scout I satellite

The main purpose of this experiment is to make accurate measurements of the primary cosmic ray energy spectrum and of the way in which this spectrum changes as a result of modulation by the inter-planetary magnetic field. The cosmic ray intensity will be measured as a function of latitude and longitude using Geiger-Muller counters, which respond to the total flux of primary particles, and a Cerenkov counter, which responds only to the heavy primaries with a charge of six or greater. An outline of the physical background to the experiment is given, together with a description of the sensor and its associated electronics.

New changes in the low-energy particle cut-Off and spectrum of the primary cosmic radiation

At the Guanafuato conference on cosmic radiation some experiments were reported which showed that the primary cosmic-ray energy spectrum as well as the low-energy cut-off are not permanent features of cosmic radiation but undergo remarkable changes with time. This suggests that the mechanism responsible for the low-energy cut-off is operating within or in the vicinity of the solar system. lt was suggested at that time that the observed phenomena may be solar controlled and related to the activity cycle of the sun. Information on changes in spectrum and cut-off was obtained by measuring the nucleonic component intensity as a function of geometric latitude at high altitude. The results of the investigation are graphically shown. (A.C.)

Direct Determination of Primary Cosmic-Ray Alpha-Particle Energy Spectrum by New Method

The flux of cosmic-ray alpha particles has been measured at $\ensuremath{\lambda}=41\ifmmode^\circ\else\textdegree\fi{}\mathrm{N} \mathrm{and} 55\ifmmode^\circ\else\textdegree\fi{}\mathrm{N}$ and the energy spectrum in the region 883-285 Mev/nucleon has been determined by the use of a combination of a scintillation and \ifmmode \check{C}\else \v{C}\fi{}erenkov counter. This spectrum is not dependent on geomagnetic theory. It has been found that the integral alpha spectrum can be fitted with the function ${J}_{0\ensuremath{\alpha}}(E)=\frac{431}{{(1+E)}^{1.4\ifmmode\pm\else\textpm\fi{}0.2}}\mathrm{particles}/{\mathrm{m}}^{2}\ensuremath{-}\mathrm{s}\mathrm{e}\mathrm{c}\ensuremath{-}\mathrm{s}\mathrm{t}\mathrm{e}\mathrm{r}\mathrm{a}\mathrm{d},$ and ${J}_{0\ensuremath{\alpha}}({E}_{1})=87\ifmmode\pm\else\textpm\fi{}9 \mathrm{particles}/{\mathrm{m}}^{2}\ensuremath{-}\mathrm{s}\mathrm{e}\mathrm{c}\ensuremath{-}\mathrm{s}\mathrm{t}\mathrm{e}\mathrm{r}\mathrm{a}\mathrm{d}, \ensuremath{\lambda}=41\ifmmode^\circ\else\textdegree\fi{}\mathrm{N},$ ${J}_{0\ensuremath{\alpha}}(0.285 \mathrm{Bev})=292\ifmmode\pm\else\textpm\fi{}25 \mathrm{particles}/{\mathrm{m}}^{2}\ensuremath{-}\mathrm{s}\mathrm{e}\mathrm{c}\ensuremath{-}\mathrm{s}\mathrm{t}\mathrm{e}\mathrm{r}\mathrm{a}\mathrm{d}, \ensuremath{\lambda}=55\ifmmode^\circ\else\textdegree\fi{}\mathrm{N}.$ ${J}_{0\ensuremath{\alpha}}(E)$ is the flux of $\ensuremath{\alpha}$ particles at the top of the atmosphere with kinetic energy $\ensuremath{\geqq}E$ (in Bev/nucleon). ${E}_{1}$ is the cutoff energy/nucleon for $\ensuremath{\alpha}$ particles at 41\ifmmode^\circ\else\textdegree\fi{}N. An absorption mean free path ${\ensuremath{\lambda}}_{\ensuremath{\alpha}}=45\ifmmode\pm\else\textpm\fi{}7$ g/${\mathrm{cm}}^{2}$ has been measured for alpha particles. The properties of this new detector are discussed and a study is made of the energy response of the \ifmmode \check{C}\else \v{C}\fi{}erenkov counter to fast multiply-charged particles.

Energy Distribution of the Primary Cosmic Radiation

The primary cosmic-ray energy spectrum usually assumed, N(E) = kE-n, where n has been assigned various values ranging from 2.5 to 2.9, by different writers obviously cannot hold for small values of the particle energy, E. To assume a cutoff of the primary radiation at an assigned value of, say, 3 or 4 Bev is also unsatisfactory, since a latitude effect at 30,000 ft,(1) as well as at balloon altitudes,(2,3) has been measured down to energies for protons to at least 1 Bev. It therefore appears (at least at the time these experiments were performed) that no definite cutoff occurs, although the energy brought in by these low energy particles must be relatively small.