High Energy Cosmic Ray Particles Research Articles

The photodisintegration of cosmic ray nuclei by solar photons: the Gerasimova-Zatsepin effect revisited

The interesting possibility of measuring the masses of high energy cosmic ray particles by observing pairs of extensive air showers arriving at the earth nearly simultaneously was proposed some years ago by Zatsepin (1951) and Gerasimova and Zatsepin (1960). Such showers would be created by the nuclear fragments originating as a result of the photodisintegration of massive nuclei interacting with the solar radiation field. In this paper we revisit this possibility in the context of existing and proposed detectors of high and ultra-high energy cosmic rays considering a simple, yet realistic, model of the interplanetary magnetic field. The possibility of observing the mass fragmentation of cosmic rays directly, however, remains challenging.

Les expositions d'origine naturelle en Suisse

L'exposition de la population la radioactivité d'origine naturelle est une caractéristique permanente et inluctable de la vie sur terre. Deux sources principales contribuent à cette exposition : les particules de haute énergie du rayonnement cosmique atteignant l'atmosphère terrestre et les nucléides radioactifs provenant de la croûte terrestre, qui marquent notre environnement comme notre propre corps. Ces sources sont responsables de notre exposition externe et interne. Les niveaux de ces expositions et leur domaine de variation en Suisse sont résumés ici et confrontés du point de vue de la dose efficace aux contributions d'origine artificielle. Il résulte que les expositions dues au bruit de fond naturel sont plus significatives pour la population que la plupart des expositions issues des sources engendrées par l'homme.

The Kascade Cosmic Ray Experiment

AbstractKascade is a large detector which is being built on the site of the Karlsruhe Nuclear Research Centre to study extensive air showers initiated by high energy cosmic ray particles in the atmosphere. The aim of the experiment is to obtain information about the chemical composition of primary cosmic rays in the energy range 500 TeV to 10 PeV, where little if anything is known at present. Special features of Kascade, as compared with previous experiments on extensive air showers, are the capability of registering many variables of a shower simultaneously and a very high rate of sampling. The design of the experiment, its present status and predicted performance are described.

Remarks on the origin of the cosmic radiation

In this article the present knowledge of the origin and acceleration of cosmic ray particles is summarized. This knowledge is obtained from investigations of the composition, the energy spectra, and the anisotropy of the radiation. Galactic objects known to accelerate particles and the process of shock acceleration are discussed. The extent of the energy spectra to 1020 eV combined with near isotropy of the flux forces one to contemplate an extragalactic origin for the cosmic rays of highest energy. At the present time one can only speculate on the sources of these particles. M ore than 20 years had passed since the discovery of cosmic radiation in 1911 when Zwicky was said to suggest that supernova explosions might be the source of this remarkable radiation. Zwicky, who investigated the supernova phenomenon, was aware that these objects produce the largest sudden energy release observed in our and similar galaxies and hence are candidates for the sources of high-energy cosmic ray particles. We know today that this was a remarkably accurate prediction, made at a time when little or nothing was known about the nature of the cosmic radiation, the interstellar medium, or the interplanetary medium through which the radiation must travel. Cosmic radiation encompasses all particles of high energy that are of astrophysical origin. It contains a wide range of species, and covers an enormous span of energies. The dominant species are protons and helium nuclei but, importantly, it also contains small quantities of all elements of the periodic system and their isotopes. In addition, electrons and the two antiparticles, positrons and antiprotons, are also observed. Missing are nuclides that decay radioactively with a lifetime too short to survive the journey between source and observer: neutrons, and many radioactive isotopes. The energies of cosmic ray particles reach 102o eV, by far the highest energy of any known radiation. The particle flux at these high energies is very small. The bulk of the cosmic rays is found around 108 and 109 eV, still high compared to laboratory standards. Particles over such a wide energy range need not necessarily be produced by the same type of source. One should not be surprised if several origins were to contribute to the observed radiation. Composition, energy spectra, and anisotropies in the arrival direction represent the most important evidence for the particle's origin and for the mechanisms leading to their acceleration. Additional evidence from gamma-ray astronomy, X-ray astronomy, and radioastronomy discloses the presence of cosmic rays in distant objects. Some of these features are now reasonably well understood, others are the subject of speculations.

Long-Term Effects of Iron Particle (HZE) Irradiation on Mouse Spermatogonia

High-energy (HZE) cosmic ray particles in space present an environmental hazard, especially to long-duration high altitude space travel. The energy released when these particles slow down and stop in living tissue causes deleterious biological effects, including death of cells. In order to study and quantitate the effects of this radiation, a number of cell systems could be used. The spermatogonial cell population in mouse testes has a rapidly dividing cell population, can be examined three days after irradiation, and is one of the most sensitive tissues to radiation. Therefore, it is ideally suited for quantitative studies of radiation effects. Previous work has shown that the various types of spermatogonial cells differ in their radiation sensitivity and that this can be very easily evaluated with the light/electron microscope. Using the system of staging established by Oak-berg and Huckins, the mixed or single cell population can be evaluated. Our work, using this method, has revealed cell sensitivity at doses as low as one rad. In these experiments, the animals were sacrificed three days post-irradiation because this is the time when maximum cell loss can be viewed. However, we are now reporting long term results of HZE particles using iron irradiation.

Variations of cosmic-ray energy in interplanetary space

A consistent theory of energy exchange between high-energy charged cosmic-ray particles and the random inhomogeneities of a magnetic field frozen in the moving solar wind plasma is developed. It is shown that the mode of the particle energy variations at a given law of plasma velocity variation in space is determined by the specific form of the particle distribution function. The equation for the density of cosmic-ray energy is obtained. Consideration is given to the generation of a charged particle energy spectrum in the course of multiple scatterings by the random inhomogeneities of the magnetic field.

On the mediation of a shock front by Fermi-accelerated cosmic rays

view Abstract Citations (69) References (16) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS On the mediation of a shock front by Fermi-accelerated cosmic rays Blandford, R. D. Abstract Fermi acceleration of high-energy cosmic ray particles by the converging fluid flows on either side of a shock front is investigated. The effect of the preshock cosmic ray pressure in mediating the shock compression and thereby the particle acceleration is studied for a shock in which this pressure can be regarded as a perturbation. The resulting spectral distortions are dictated by the energy dependence of the spatial diffusion coefficient and the Mach number of the shock. Examples are computed for diffusion coefficients independent of and proportional to the particle momentum. The implications of these results for the efficiency of the particle acceleration mechanism are briefly discussed. Publication: The Astrophysical Journal Pub Date: May 1980 DOI: 10.1086/157998 Bibcode: 1980ApJ...238..410B Keywords: Cosmic Rays; Energetic Particles; High Energy Interactions; Particle Acceleration; Shock Fronts; Diffusion Coefficient; Energy Spectra; Mach Number; Particle Diffusion; Perturbation Theory; Relativistic Particles; Space Radiation full text sources ADS |

Suprathermal grains: On intergalactic magnetic fields

Charged dust grains of radiia≃3×10−6∼3×10−5 cm may be driven out of the galaxy due to radiation pressure of starlight. Once clear of the main gas-dust layer, dust grains may then escape into intergalactic space. Such grains are virtually indestructible-being evaporated only during galaxy formation. The dust grains, once injected into the intergalactic medium, may acquire suprathermal energy, thus ‘suprathermal grains’ in collision with magnetized cloud by the Fermi process. In order to attain relativistic energy, suprathermal grains have to move in and out (‘scattering’) of the magnetic field of the medium. It is now well established that high energy cosmic rays are of the order 1020 eV or more. We have speculated that these high energy (>-1018 eV) cosmic ray particles are charged dust grains, of intergalactic origin. This is possible only if there exists a magnetic field in the intergalactic medium.

Elastic scattering of target protons in nucleon-nucleus collisions

The study of elastic nucleon-nucleon collisions in the energy region above 100 GeV is of special interest in respect of 1) the primary-energy dependence of the total elastic cross-section and 2) the increase of interaction radius of a nucleon with increasing primary energy, which have been conjectured by the extensive studies in the energy region below 30 GeV. At present, since cosmic rays are the only source for high-energy particles (> 100 GeV), the problem is not explored as has been done at accelerator energy. The elastic scatterings of high-energy cosmic-ray particles by free protons or protons in a target nucleus which give rise to only one visible grey or black track (iV h : 1) in nuclear emulsion are very rare and it is difficult to find them. Only a few such experiments have so far been carried out (1.s). There is, however, a probability in an inelastic nucleon-nucleus collision that an incident pr imary nucleon, during the collision with nucleus, collides elastically with other nucleons in the same nucleus producing (( knock-on protons ~ which appear as grey tracks ((30--500) MeV) in nuclear emulsion. The frequency of these elastic p-p collisions in nuclei depends on I) the total elastic p-p cross-section and II) the interaction radius of the nucleon. A rough estimate shows that these elastic protons are expected to be ~ 0.5 per proton-light-nucleus (Z = 7) collision if a 5 mb total elastic cross-section when 1 fm interaction radius is assumed. Therefore, the problems I) and II) mentioned above can be investigated by using knock-on protons associated with inelastic nucleonnucleon interactions. A sample of 67 nucleon-light-nucleus interactions with ZTh~ 7 and primary energy between 50 and 10 a GeV found in the Dublin part of the ICEF stack has been analysed. The grain density, multiple scattering and in some cases the range were measured for all grey tracks whose dip angles to emulsion surface were ~ 30 ~ Also the energy and the polar angle to the direction of the primary of those tracks have been determined. We identified 41 knock-on protons with kinetic energy greater than 30 5[eV. The analysis for nucleon-nucleus events is based on this sample and is shown in Table I. The number of knock-on protons Pk observed, with dip angle ~ 30 ~ is given in the 4th and 5th line of Table I for E(pk)~ 30 MeV.

Monte Carlo Simulation on Propagation of Cosmic-Rays in the Atmosphere

A simulation study is made on propagation and multiplication of the high energy cosmic-ray components in their passage through the atmosphere. The study is planned to simulate observation of high energy cosmic-ray phenomena by the emulsion chambers exposed at high altitude laboratories and to make clear how the observation of such kind will disclose unknown mechanism of the extremely high energy interactions-multiple production of mesons. In particular, the following two models of the multiple meson production are examined in the present simulation: 1) Two-fire-ball model,l> abbreviated as 2F; 2) H-quantum model,2> abbreviated as HQ. The outline of our simulation is as follows. A high energy primary cosmic-ray particle collides with an air nucleus of the upper atmosphere and causes the multiple meson production according to mechanism of the assumed models. The secondary nuclear-active particles, charged n-mesons and an outgoing nucleon, among the generated particles collide in their turn with air nuclei and they develop the so-called nuclear cascade processes while passing through the atmosphere. Gamma-rays, being the decay products of n°-mesons produced by the successive nuclear collisions, are the source of the atmospheric electromagnetic cascade showers. We make a record of particles with energies above a certain threshold energy both of the nuclear-active component and of the electro-magnetic component, which arrived at the observation level. The record consists of data of the arriving particles together with those on the primary particle. The present simulation calculation corresponds to observation of high energy cosmic-ray particles by the emulsion chamber exposed at the mountain altitudes. In particular, it provides us data of the artificial families: identity, energy and spatial distribution of member particles of the families. It is instructive to learn what kind of pattern the artificial families show at the observation plane under a certain assumption. This is indispensable for

Trajectories of high-energy cosmic rays in the galactic disk

Trajectories of high-energy cosmic ray particles, the rigidity of which corresponds to protons of energy E0 = 1018 eV, have been calculated numerically, using a quasi-longitudinal model of the magnetic field in the galactic disk. In this way an idea of cosmic radiation transfer at extremely high energies is obtained under specified assumptions concerning the magnetic field in the galactic disk. The galactic or extragalactic origin of particles reaching the Earth, as well as the angular distribution of such particles, is discussed. The possibility of particle transfer from the galactic centre to the Earth is investigated.

Inelastic cross sections of nucleons and π mesons in carbon and lead near 100 GeV

An experiment to measure the cross section for high-energy cosmic-ray neutrons and charged nuclear-active particle interactions with Pb and C nuclei has been carried out at an altitude of 2 000 m. Large spark chambers were used in a detector which selected neutrons and charged nuclear-active particles in the region of 100 GeV. The results are σπ(nPb) = (1.65 ± 0.17) barn, σπ(nC) = (0.204 ± 0.02) barn, σπ(πPb) = (1.53 ± 0.17) barn, σπ(πC) = (0.168 ± 0.017) barn.

A Study of High Energy Nuclear Interactions with Large Emulsion Cloud Chamber

A large emulsion cloud chamber (E. C. C.) carried by a balloon was exposed at high altitude (October, 1963, Kobe). The characteristics of the interactions of high energy cosmic ray particles (\({\gtrsim}10^{13}\) eV) with other nuclei were examined. Forty-two events with energies higher than 10 12 eV were observed, from which the events of nuclear interactions in the carbon producer were selected. The transverse momenta of γ-rays which were the decay products of π°-mesons emitted from jets were estimated at 230 MeV/c (assuming that the P t distribution of γ-ray resembles that of π°'s, and the average P t value of π° is about twice that of γ). The curve of P t distribution does not fit the Gaussian form. In the energy region of about 10 12 eV, the energy spectrum can be fit by single power laws of 1.50±0.42 for Σ E γ , and 1.60±0.25 for E γ . There is no correlation between P t and E γ .

ANGULAR DISTRIBUTION OF NUCLEAR INTERACTIONS OF HIGH ENERGY COSMIC RAY PARTICLES WITH PARAFFIN

A cloud chamber experiment is described, in which the angular distribution of secondary particles produced in nuclear interaction by high energy cosmic ray particles with paraffin has been studied. Sixty-four ns ≥4 events with average primary energy of 70 BeV have been analysed. The result shows that, in this energy region, the angular distribution in CMS is not isotropic but possesses maxima in the 0° and 180° directions; furthermore, there is already an appreciable fraction ( 20%) of the events with angular distribution exhibiting the features given by the fire-ball model.

Information that isotopic measurements provide about space and the cosmos

The study of the isotopic abundances of the rare gases helium, neon, and argon in iron meteorites lead to the conclusion that the rare gases are produced mainly by the action of the cosmic rays with the meteorites. The high energy cosmic ray particles produce nuclear spallation reactions with the elements composing the meteorites. By comparing the cosmic-ray produced radioactive isotopes of different half lives such as H/sup 3/, Ar/sup 37/, Ar/sup 39/, Cl/sup 36/, Al/su p 26/, Be/sup 10/, and K/sup 40/ it is possible to investigate the constancy of cosmic rays in time and space. The measurements indicate that during the last 500,000 years there was no greater than a 10% change in the intensity of cosmic rays, and that cosmic rays near the earth have about the same intensity as cosmic rays in the asteroidal belt some 450 million kilometers further from the sun. In addition there is evidence that indicates that some of the meteorites have undergone collisions in space previous to being captured by the earth. (auth)

Triggered spark counter arrays of large area (square meters) for experiments on very high energy cosmic ray particles

The constructional and operational features of triggered spark counters of large area are described. These counters are being used, in conjunction with nuclear emulsions, in current experiments in this laboratory on high energy nuclear interacting particles which arrive simultaneously over large areas, sometimes associated and at other times unassociated with air showers. For these experiments the spark counters and emulsions are being used in arrays covering an area of a few square meters.

Explosive showers produced by high-energy cosmic-ray particles

BS>This paper was previously abstracted from the original language and appears in NSA, Vol. 12. as abstract No. 9250.

Multiple Events Produced in Hydrogen by Very High Energy Cosmic-Ray Particles at an Altitude of 90,000 Feet

Multiple Events Produced in Hydrogen by Very High Energy Cosmic-Ray Particles at an Altitude of 90,000 Feet

Multiple Events Produced in Hydrogen by Very High Energy Cosmic-Ray Particles at an Altitude of 90,000 Feet

Multiple Events Produced in Hydrogen by Very High Energy Cosmic-Ray Particles at an Altitude of 90,000 Feet

XCIX. Experiments with nuclear-track emulsions sensitive at minimum ionizing power

Summary The angular distribution of straight-line tracks duo to high energy cosmic ray particles at sea level and their number per cm.2 per day at sea level and below an absorber (equivalent to 60 m. of water) have been investigated. Slow electron tracks are recorded at a rate of 104 per cm.2 per day in a 200 micron thickemulsion. The sensitivity of the emulsion to particles at minimum ionization does not change at low temperature (-80° C), although a decrease of 24 per cent was found for X-ray exposures at -80° C. as compared with room temperature. A number of pair formation tracks produced by a 25 MeV. synchrotron have been observed. In all cases but two, one particle (presumably the positron) stops in the emulsion before slowing down. Two examples of elastic collisions between particles at minimum ionization and electrons and the formation of a multiple star are discussed.