EVAPORATION NEUTRONS FROM COSMIC RAY NUCLEAR INTERACTIONS IN VARIOUS ELEMENTS

1956 ◽  
Vol 34 (3) ◽  
pp. 288-303 ◽  
Author(s):  
K. W. Geiger
Keyword(s):  
Cosmic Rays ◽  
Cross Section ◽  
Cross Sections ◽  
Boron Trifluoride ◽  
Cosmic Ray ◽  
Atomic Weight ◽  
Nuclear Interactions ◽  
The Mean ◽  
Neutron Multiplicities ◽  
Interaction Cross Sections

Production of evaporation neutrons from nuclear interactions by cosmic rays is investigated in C, Al, Fe, Cu, Pb, and Bi. Boron trifluoride counters in a paraffin moderator in which the element under study is placed serve to detect the evaporation neutrons. A cosmic ray telescope allows the consideration of ionizing neutron-producing particles separately and it is found that of the total neutrons 14.6% are produced by ionizing particles. The mean neutron multiplicities are worked out and they show an increase with the two-thirds power of the atomic weight of the element in which the interactions take place. Also, the rate of interactions is calculated and this gives the relative interaction cross-sections which are found to increase slightly more with atomic weight than expected if the cross-section is geometric. An estimate of the intensity of the N-component is made and discussed in connection with measurements published by other authors.

Anomalous interactions of secondary particles emitted from relativistic heavy primary interactions

1968 ◽  
Vol 46 (5) ◽  
pp. 343-358 ◽  
Author(s):  
B. Judek
Keyword(s):  
Cross Section ◽  
Cosmic Ray ◽  
Secondary Particles ◽  
Nuclear Interactions ◽  
Charged Secondary ◽  
Singly Charged

Interaction mean free paths of relativistic secondary particles emitted from interactions of heavy primary cosmic-ray nuclei in emulsions were measured. The results show that among the Be, Li, He, and singly charged secondary nuclei there are particles present which interact with a cross section several times higher than the expected geometrical value. The stars produced by these particles have the characteristics of ordinary nuclear interactions. There appears to be no interpretation of these observations in terms of any known particle phenomena.

scholarly journals Quantitative Ausmessung des Brom-Affinitätskontinuums und Bestimmung der Detachment-und Attachment-Querschnitte

1970 ◽  
Vol 25 (11) ◽  
pp. 1617-1626 ◽  
Author(s):  
H. Frank ◽  
M. Neiger ◽  
H.-P. Popp
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Electron Affinity ◽  
Elastic Cross Section ◽  
Electron Atom ◽  
Intensity Measurements ◽  
Long Wave ◽  
The Mean ◽  
Intense Electron

Abstract A wall stabilized low-current cylindric arc was used to produce the radiation of the negative Bromine-ions. The radiation consists of an affinity-continuum with a long-wave threshold of 3682 Å, yielding an electron affinity for Bromine of 3.366 eV, and of an intense electron-atom Bremsstrahlung in the visible. Intensity measurements of the continua allow the determination of the photo-detachment-and attachment-cross-sections of Bromine and also the determination of the mean elastic cross-section of electrons against Bromine atoms.

scholarly journals Are Further Cross Section Measurements Necessary for Space Radiation Protection or Ion Therapy Applications? Helium Projectiles

2020 ◽  
Vol 8 ◽  
Author(s):  
John W. Norbury ◽  
Giuseppe Battistoni ◽  
Judith Besuglow ◽  
Luca Bocchini ◽  
Daria Boscolo ◽  
...  
Keyword(s):  
Radiation Protection ◽  
Cross Section ◽  
Cross Sections ◽  
Nuclear Reactions ◽  
Production Cross ◽  
Cosmic Ray ◽  
Space Radiation ◽  
Radiation Shielding ◽  
Light Ions ◽  
Ion Therapy

The helium (4He) component of the primary particles in the galactic cosmic ray spectrum makes significant contributions to the total astronaut radiation exposure. 4He ions are also desirable for direct applications in ion therapy. They contribute smaller projectile fragmentation than carbon (12C) ions and smaller lateral beam spreading than protons. Space radiation protection and ion therapy applications need reliable nuclear reaction models and transport codes for energetic particles in matter. Neutrons and light ions (1H, 2H, 3H, 3He, and 4He) are the most important secondary particles produced in space radiation and ion therapy nuclear reactions; these particles penetrate deeply and make large contributions to dose equivalent. Since neutrons and light ions may scatter at large angles, double differential cross sections are required by transport codes that propagate radiation fields through radiation shielding and human tissue. This work will review the importance of 4He projectiles to space radiation and ion therapy, and outline the present status of neutron and light ion production cross section measurements and modeling, with recommendations for future needs.

The determination of the cross sections for the reactions 27 Al( n , α ) and 56 Fe( n , p ) for 14 MeV neutrons by an absolute method

1966 ◽  
Vol 292 (1429) ◽  
pp. 180-192 ◽  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Standard Error ◽  
Particle Method ◽  
Systematic Errors ◽  
Aluminium Foil ◽  
The Mean ◽  
The Cross ◽  
Experimental Values

Measurements of the cross sections for the reactions 27 Al( n , α ) 24 Na and 56 Fe( n, p ) 56 Mn for neutrons of energy 13.5 ± 0.1 MeV have been made by a radioactivation method. The neutron flux was determined by a variant of the 'associated particle’ method, in which the α -particles produced concurrently with the neutrons from the D + T reaction were estimated in terms of the volume of helium which accumulated when they were brought to rest in an aluminium foil. Cross section values obtained at 13.5 MeV were: for 27 Al( n , α ): 118.1 ± 6.0 mb : for 56 Fe( n, p ): 106.7 ± 4.7 mb. The errors quoted include both the standard error on the mean of the experimental values and an estimate of possible residual systematic errors. The excitation functions for both reactions in the energy region 13.5 to 14.8 MeV have also been investigated, in order to provide secondary cross section values over this range of energies. At 14.8 MeV the values found were: 27 Al( n , α )103.6 ± 5.5 mb; 56 Fe( n, p )96.7 ± 4.5 mb.

GLUON SATURATION AND THE TOTAL PROTON-AIR CROSS SECTION

2010 ◽  
Vol 19 (08n10) ◽  
pp. 1685-1689
Author(s):  
F. CARVALHO ◽  
F. O. DURÃES ◽  
S. SZPIGEL ◽  
F. S. NAVARRA
Keyword(s):  
Simple Model ◽  
Cross Section ◽  
Cross Sections ◽  
Cosmic Ray ◽  
Dipole Model ◽  
Perturbative Calculations ◽  
Experimental Cross ◽  
Energy Behavior ◽  
Gluon Saturation

In this work we propose a simple model for the total proton-air cross section, which is an improvement of the minijet model with the inclusion of a window in the pT-spectrum associated to the saturation physics. Our approach introduces a natural cutoff for the perturbative calculations which modifies the energy behavior of this component. The saturated component is calculated with a dipole model. The results are compared with experimental cross sections measured in cosmic ray experiments.

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

1968 ◽  
Vol 46 (10) ◽  
pp. S694-S696 ◽  
Author(s):  
A. V. Alakoz ◽  
V. N. Bolotov ◽  
M. I. Devishev ◽  
L. F. Klimanova ◽  
A. P. Shmeleva
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Cosmic Ray ◽  
High Energy ◽  
Active Particle ◽  
Particle Interactions ◽  
Active Particles ◽  
The Cross

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.

Cosmic-ray nuclei up to 10 10 eV/u in the galaxy

1975 ◽  
Vol 277 (1270) ◽  
pp. 319-348 ◽  
Keyword(s):  
Cosmic Rays ◽  
Solar System ◽  
Cross Sections ◽  
Cosmic Ray ◽  
Interstellar Space ◽  
Heavy Nuclei ◽  
Hydrogen Atoms ◽  
Interstellar Gas ◽  
The Galaxy ◽  
Ionization Cross Sections

O f the nuclear cosmic rays arriving in the vicinity of Earth from interstellar space, more than 90% have energies less than 1010 eV /u.f Some effects of their modulation (including deceleration) in the Solar System are briefly discussed. The origin of particles at energies < 107 eV/u is still obscure. They could be due to stellar explosions or to solar emissions, or perhaps to interaction of interstellar gas with the solar wind. Between 108 and 1010 eV/u, the composition appears constant to ca. 30% within the statistics of available data. Cosmic rays traverse a mean path length of 6 g/cm 2 in a medium assumed to contain nine hydrogen atoms for each helium atom. Spallation reactions occurring in this medium result in enhancement of many cosmic-ray elements that are more scarce in the general abundances by several orders of magnitude. Cosmic-ray dwell time in the Galaxy seems to be < 107 years. The source composition of cosmic rays has been derived for elements with atomic numbers 1 ≤ Z ≤ 26. A comparison with abundances in the Solar System implies that the latter is richer in hydrogen and helium by a factor of ca. 20, in N and O by ca. 5, and in C by a factor of ca.2. Possible interpretations invoke (a) nucleosynthesis of cosmic rays in certain sources, e.g. supernovae, or (b) models of selective injection that depend, e.g. on ionization potentials or ionization cross sections. Calculated isotopic abundances of arriving cosmic rays are compared with the observed values now becoming available, and found to be in general agreement. Recent progress in probing the composition and spectrum of ultra-heavy nuclei is outlined.

scholarly journals Cosmic Ray Antiprotons 5–12 GeV

1981 ◽  
Vol 94 ◽  
pp. 257-258 ◽  
Author(s):  
T. K. Gaisser ◽  
A. J. Owens ◽  
Gary Steigman
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Production Cross Section ◽  
Production Cross ◽  
Cosmic Ray ◽  
Image Position ◽  
Energy Dependent ◽  
Complex Nuclei

Secondary antiprotons are a potentially interesting probe of cosmic ray propagation because their production cross section is strongly energy-dependent, increasing by more than two orders of magnitude between 10 and 1000 GeV/c. This is quite unlike the case for fragmentation cross sections of complex nuclei, which are virtually constant with energy. Moreover, the flux depends primarily on the environment seen by protons which need not be identical to that probed by other nuclei.

Cosmic Ray Interactions in Paraffin and Lead

1969 ◽  
Vol 24 (10) ◽  
pp. 1541-1543
Author(s):  
J. P. Mundra ◽  
D. P. Bhattacharyya ◽  
P. K. Senchaudhury
Keyword(s):  
Cosmic Rays ◽  
Cosmic Ray ◽  
Nuclear Interaction ◽  
Cloud Chamber ◽  
Continuous Increase ◽  
Transition Effect ◽  
Cosmic Ray Interactions ◽  
Nuclear Interactions

Abstract Nuclear interactions of cosmic rays under paraffin and lead have been studied by means of a counter controlled multiplate cloud chamber. The lead plates inside the chamber served as producer and analyser. A search has been made for the possible transition effect of nuclear interaction in lighter elements using charged components for triggering and to compare it with a previously observed apparent transition effect in graphite for neutron shower using coincidence of neutron counters. The results show a continuous increase of nuclear interaction with increasing thickness of paraffin absorber up to 30.4 gcm-2. A similar rise is also observed under 11.3 gem-2 of Pb.

scholarly journals Deexcitation Probabilities of Ne(3P2) by Kr for the Case E << D

1970 ◽  
Vol 24 ◽  
pp. 45-48
Author(s):  
Deba Bahadur Khadka
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Chemical Society ◽  
Ionization Cross ◽  
Penning Ionization ◽  
Collisional Energy ◽  
Theoretical Investigations ◽  
Probability Calculation ◽  
The Mean ◽  
Made In

The deexcitation probability calculation of the total Penning ionization cross section for Ne(3P2) by Kr has been made in the region of the collisional energy from 18.5 to 38.1 meV. Considering the magnitude of the mean collisional energy with respect to D, the application of the analysis in the case E >> D is expected to be more appropriate than in the case E << D. Theoretical investigations of Ne(3P2) by Kr for the case E >> D are also needed.Keywords: metastable atoms, resonance atoms, deexcitation cross sections, pulse radiolysis, impact parameter.DOI: 10.3126/jncs.v24i0.2390Journal of Nepal Chemical Society Vol.24 Page 45-48

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