The low-energy cosmic-ray nuclei and their propagation in interstellar space

1968 ◽  
Vol 46 (10) ◽  
pp. S553-S556 ◽  
Author(s):  
G. M. Comstock
Keyword(s):  
Additional Data ◽  
Cosmic Ray ◽  
Low Energy ◽  
Energy Spectra ◽  
Interstellar Space ◽  
Loss Measurement ◽  
Depletion Depth ◽  
Two Component ◽  
The University ◽  
Component Models

The differential energy spectra of the cosmic-ray nuclei helium, carbon, nitrogen, and oxygen above 30 MeV/nucleon, boron, neon, magnesium, and silicon above 50 MeV/nucleon, and the iron group above 100 MeV/nucleon, measured in October–December 1964 and May–June 1965 by the University of Chicago charged-particle telescope on board the OGO-I satellite (Comstock et al. 1966b), have been corrected to take account of the effective depletion depth of the gold–silicon solid-state detectors used for rate-of-energy-loss measurement. Additional data from October to December 1965 are included. The magnitudes and relative shapes of the spectra deduced by extrapolation to nearby interstellar space place important constraints on the allowed modes of interstellar propagation for these nuclei. Two-component models are shown to account for most of the observed properties of the interstellar cosmic-ray nuclei.

Composition and spectra of primary cosmic-ray electrons and nuclei above 10 10 eV

1975 ◽  
Vol 277 (1270) ◽  
pp. 349-363 ◽  
Keyword(s):  
Cosmic Ray ◽  
High Energy ◽  
Energy Spectra ◽  
Average Lifetime ◽  
Interstellar Space ◽  
Interstellar Matter ◽  
Electromagnetic Interactions ◽  
Nuclear Species ◽  
The Galaxy ◽  
High Energy Particles

Recent experiments have extended the knowledge of the flux and energy spectra of individual cosmic-ray components to much higher energies than had previously been accessible. Both electron and nuclear components show a behaviour at high energy which is unexpected, and which carries information regarding the sources and the propagation of particles between sources and observer. Electromagnetic interactions which are suffered by the electrons in interstellar space should steepen their spectrum, a steepening that would reveal the average lifetime a cosmic-ray particle spends in the galaxy. Measurements up to 1000 GeV show no such steepening. It was discovered that the composition of the nuclear species which is now measured up to 100 GeV/nucleon changes with energy. This change indicates traversal of less interstellar matter by the high energy particles than by those of lower energy. We discuss the experimental evidence and its implication.

Low-Energy Cosmic-Ray Composition and Energy Spectra Measured in June 1965

1967 ◽  
Vol 162 (5) ◽  
pp. 1291-1295 ◽  
Author(s):  
D. V. Reames ◽  
C. E. Fichtel
Keyword(s):  
Cosmic Ray ◽  
Low Energy ◽  
Energy Spectra

Low-energy cosmic-ray heavy nuclei during the time of solar minimum

1968 ◽  
Vol 46 (10) ◽  
pp. S598-S600
Author(s):  
E. Tamai ◽  
M. Tsubomatsu ◽  
K. Ogura
Keyword(s):  
Energy Range ◽  
Solar Minimum ◽  
Cosmic Ray ◽  
Low Energy ◽  
Energy Spectra ◽  
Solar Modulation ◽  
Atmospheric Depth ◽  
Heavy Nuclei ◽  
Multiply Charged ◽  
Α Particles

Nuclear emulsions were exposed at 2.3 g cm−2 atmospheric depth over Fort Churchill in 1965. These emulsions have been examined for the tracks of multiply-charged [Formula: see text] nuclei, with emphasis being paid particularly to those particles that stopped in the emulsions. Differential energy spectra of α particles and [Formula: see text], [Formula: see text]and [Formula: see text] nuclei were obtained in the energy interval 60–550 MeV/nucleon. They represent experimental results during the period when solar modulation effects were at a minimum. The fluxes of α particles and L, M, and H nuclei for energy intervals of 60–170, 100–400, 100–525, and 140–550 MeV/nucleon were found to be 20.9 ± 1.2, 2.4 ± 0.4, 4.8 ± 0.6, and 2.5 ± 0.4 particles m−2 sr−1 s−1, respectively. The results also show that the L/M and H/M ratios at the top of the atmosphere were 0.56 ± 0.16 and 0.34 ± 0.13 respectively, in the energy range from 140 to 350 MeV/nucleon. These values are appreciably greater than those observed at higher energies.

Galactic ?-ray Lines Resulting from Interactions Between Low Energy Cosmic Rays and the Interstellar Medium

1979 ◽  
Vol 32 (4) ◽  
pp. 383 ◽  
Author(s):  
Masato Yoshimori
Keyword(s):  
Cosmic Rays ◽  
Supernova Remnants ◽  
Galactic Plane ◽  
Crab Nebula ◽  
Cosmic Ray ◽  
Low Energy ◽  
Longitudinal Distribution ◽  
Galactic Centre ◽  
Interstellar Space ◽  
Interstellar Gas

Calculated spectral profiles and galactic distributions are presented for y-ray lines resulting from interactions between low energy cosmic rays and the interstellar gas and dust. Calculated local intensities are also presented for y-ray lines from discrete sources such as supernova remnants and dense interstellar gas clouds. The y-ray lines from excited dust nuclei (which have long mean lifetimes) are sharp, having widths of the order of a few keV; the lines from excited gas nuclei are relatively narrow, having widths of the order of 100 keV; and the lines from excited cosmic ray nuclei are broad, having widths of the order of 1 MeV. The longitudinal distribution of y-ray lines in the galactic plane shows a significant concentration toward the galactic centre, and a rapid falloff beyond I;. 50�. The most intense y-ray lines arise from positron annihilation (0�511 MeV) and the deexcitation of 12C* (4�439 MeV) and 160* (6�131 MeV). In the direction of the galactic centre, these lines have estimated intensities of the order of 10-5 photons cm-2s-1rad- 1, and so they may be resolved from the diffuse y-ray background there by observing with a high resolution Ge(Li) detector. In the direction of several strong discrete sources, the estimated fluxes are generally lower: ~10-6 photons cm-2s-1 for the Crab Nebula and the Vela pulsar, ~10-8 photons cm-2 s-1 for the interstellar dense cloud pOph, but ~10-5 photons cm-2 s-1 for the ring cloud around the galactic centre. The calculated intensities of various other y-ray lines are compared with available experimental data, and their detectability is considered. The implication of the galactic distribution of low energy cosmic rays for the gas density of the interstellar space through which the cosmic rays propagate is also discussed.

Two anisotropies of the cosmic-ray particles producing the cosmic-ray diurnal variation

1968 ◽  
Vol 46 (10) ◽  
pp. S828-S830
Author(s):  
Masatoshi Kitamura
Keyword(s):  
Cosmic Rays ◽  
Diurnal Variation ◽  
Interplanetary Space ◽  
Geomagnetic Latitude ◽  
Cosmic Ray ◽  
Diurnal Variations ◽  
Low Energy ◽  
The Other ◽  
Energy Spectra ◽  
Cosmic Ray Intensity

The solar diurnal variations of both meson and nucleon components of cosmic rays at sea level at geomagnetic latitude 57.5° and geomagnetic longitude 0° are analyzed by the model in which two anisotropies of cosmic-ray particles (one of them, Δj1, from about 20 h L.T. and the other, Δj2, from about 8 h L.T. in interplanetary space) produce the solar diurnal variation of the cosmic-ray intensity on the earth.When the energy spectra of Δj1 and Δj2 are represented by [Formula: see text] and [Formula: see text], respectively, where j0(E) is the normal energy spectrum of the primary cosmic rays, it is shown that the evaluation for m1 = 1, 2, m2 = 0 and the cutoffs at 8 and 10 BeV on the low-energy side of spectra of both Δj1 and Δj2 agree well with the observational results at Deep River.

The composition of low-energy cosmic rays in 1965

1968 ◽  
Vol 46 (10) ◽  
pp. S539-S543 ◽  
Author(s):  
D. E. Hagge ◽  
V. K. Balasubrahmanyan ◽  
F. B. McDonald
Keyword(s):  
Cosmic Rays ◽  
Energy Range ◽  
Cosmic Ray ◽  
Low Energy ◽  
Oxygen Flux ◽  
Energy Spectra ◽  
Solar Modulation ◽  
Charge Composition ◽  
Specific Component ◽  
Relative Abundances

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.

scholarly journals First-of-a-kind muography for nuclear waste characterization

2018 ◽  
Vol 377 (2137) ◽  
pp. 20180048 ◽  
Author(s):  
David Mahon ◽  
Anthony Clarkson ◽  
Simon Gardner ◽  
David Ireland ◽  
Ramsey Jebali ◽  
...  
Keyword(s):  
Nuclear Waste ◽  
Imaging System ◽  
Academic Research ◽  
Cosmic Ray ◽  
Laboratory Facility ◽  
Waste Container ◽  
High Resolution Images ◽  
And Performance ◽  
The Uk ◽  
The University

In the last decade, there has been a surge in the number of academic research groups and commercial companies exploiting naturally occurring cosmic-ray muons for imaging purposes in a range of industrial and geological applications. Since 2009, researchers at the University of Glasgow and the UK National Nuclear Laboratory (NNL) have pioneered this technique for the characterization of shielded nuclear waste containers with significant investment from the UK Nuclear Decommissioning Authority and Sellafield Ltd. Lynkeos Technology Ltd. was formed in 2016 to commercialize the Muon Imaging System (MIS) technology that resulted from this industry-funded academic research. The design, construction and performance of the Lynkeos MIS is presented along with first experimental and commercial results. The high-resolution images include the identification of small fragments of uranium within a surrogate 500-litre intermediate level waste container and metal inclusions within thermally treated GeoMelt® R&D Product Samples. The latter of these are from Lynkeos' first commercial contract with the UK National Nuclear Laboratory. The Lynkeos MIS will be deployed at the NNL Central Laboratory facility on the Sellafield site in Summer 2018 where it will embark upon a series of industry trials. This article is part of the Theo Murphy meeting issue ‘Cosmic-ray muography’.

Time-resolved ion cyclotron resonance

1978 ◽  
Vol 364 (1718) ◽  
pp. 367-381 ◽  
Keyword(s):  
Cyclotron Resonance ◽  
Low Energy ◽  
Interstellar Space ◽  
Ion Cyclotron Resonance ◽  
Absolute Rate ◽  
Time Resolved ◽  
Ion Molecule Reactions ◽  
Quadrupole Trap ◽  
Ion Cyclotron ◽  
Improved Technique

Ion cyclotron resonance (i. c. r.) is a technique for the study of ion-molecule reactions in the collisional range from thermal to several electron volts. The study of these reactions at low energy has been given impetus by the discovery of their importance in the ionosphere and in interstellar space. This communication identifies some possible weaknesses inherent in current i. c. r. work and suggests an improved technique with which it is possible to determine absolute rate constants more reliably. As an illustration of the technique a measurement of the rate constant for the reaction CH 4 + + CH 4 → k CH 5 + + CH 3 is presented. This value is k = 1.21 ± 0.09 × 10 -15 m 3 s -1 . A new i. c. r. cell design is discussed with which it is hoped to provide further improvement in reliability by the production of a homogeneous radiofrequency field within a true quadrupole trap.

EARLY RESULTS FROM THE HIGH-RESOLUTION FLY's EYE

2001 ◽  
Vol 16 (supp01c) ◽  
pp. 1019-1021
Author(s):  
JOHN BELZ
Keyword(s):  
High Resolution ◽  
Cosmic Ray ◽  
Energy Spectra ◽  
Fluorescence Technique ◽  
Early Results ◽  
One Year ◽  
High Resolution Fly's Eye

The High-Resolution Fly's Eye cosmic ray observatory has been operating in monocular (stereo) mode for about three years (one year), during which time we have observed extensive airshowers with an integrated aperture of ~ 1500 km2-sr-yr (~ 400 km-sr-yr) at 5×1019 eV. We describe the HiRes experiment and the nitrogen fluorescence technique, and present data taken in both monocular and stereo modes including preliminary energy spectra.

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