scholarly journals On the stopping of fast particles and on the creation of positive electrons

1934 ◽  
Vol 146 (856) ◽  
pp. 83-112 ◽  
Keyword(s):  
Quantum Mechanics ◽  
Cross Section ◽  
Nuclear Charge ◽  
Primary Energy ◽  
Stopping Power ◽  
Nuclear Scattering ◽  
The Third ◽  
High Energies ◽  
Order Of Magnitude ◽  
Very High

The stopping power of matter for fast particles is at present believed to be due to three different processes: (1) the ionization; (2) the nuclear scattering; (3) the emission of radiation under the influence of the electric field of a nucleus. The first two processes have been treated in quantum mechanics by Bethe, Møller, and Bloch in a very satisfactory way. A provisional estimation of the order of magnitude to be expected in the third process has been given by Heitler. The result obtained was that the cross-section ϕ for the energy loss by radiation for very fast particles (if the primary energy E 0 ≫ mc 2 ) is of the order ϕ ∽ Z 2 /137 ( e 2 / mc 2 ) 2 , (1) Where Z is the nuclear charge. It is the aim of the present paper to discuss in greater detain the rate of loss of energy by this third process and its dependence on the primary energy; in particular we shall consider the effect of screening . The results obtained for very high energies (> 137 mc 2 ) seem to be in disagreement with experiments made by Anderson ( cf . 7).

Electron Energy Dependence of Amorphization in Zr3Fe

1993 ◽  
Vol 316 ◽  
Author(s):  
A.T. Motta ◽  
L.M. Howe ◽  
P.R. Okamoto
Keyword(s):  
Electron Energy ◽  
Cross Section ◽  
Sharp Increase ◽  
Low Dose ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
High Energies ◽  
Intermediate Energies ◽  
Low Energies ◽  
Order Of Magnitude

ABSTRACTThis paper reports the results from a study conducted to determine the effect of electron energy on the dose-to-amorphization of Zr3Fe at 23-30 K. Zr3Fe samples were irradiated in the HVEM at Argonne National Laboratory, at energies ranging from 200 to 900 keV. Amorphization occurred at electron energies from 900 keV down to 250 keV. Three distinct regions were observed: between 900 and 700 keV amorphization occurred at a constant low dose of ~ 4 × 1021 e cm-2; a higher plateau at 1022 was observed between 600 and 400 keV, and finally there was a sharp increase in the dose-to-amorphization below 400 keV, so that at 250 keV the necessary dose was an order of magnitude higher than that at 900 keV. In the region below 400 keV there was evidence of a dependence of the dose-to-amorphization on the orientation of the sample with respect to the electron beam. The results can be analyzed in terms of a composite displacement cross section dominated at high energies by displacements of Zr and Fe atoms, by displacements of Fe atoms at intermediate energies and of secondary displacements of lattice atoms by recoil impurities at low energies.

scholarly journals ADELIC HARMONIC OSCILLATOR

1995 ◽  
Vol 10 (16) ◽  
pp. 2349-2365 ◽  
Author(s):  
BRANKO DRAGOVICH
Keyword(s):  
Quantum Mechanics ◽  
Harmonic Oscillator ◽  
Functional Relation ◽  
Vacuum State ◽  
One Dimensional ◽  
High Energies ◽  
The Riemann Zeta Function ◽  
Adelic Quantum Mechanics ◽  
Riemann Zeta ◽  
Very High

Using the Weyl quantization we formulate one-dimensional adelic quantum mechanics, which unifies and treats ordinary and p-adic quantum mechanics on an equal footing. As an illustration the corresponding harmonic oscillator is considered. It is a simple, exact and instructive adelic model. Eigenstates are Schwartz-Bruhat functions. The Mellin transform of the simplest vacuum state leads to the well-known functional relation for the Riemann zeta function. Some expectation values are calculated. The existence of adelic matter at very high energies is suggested.

scholarly journals Taming the Energy Rise of the Total Proton-Proton Cross-Section

Universe ◽  
2019 ◽  
Vol 5 (5) ◽  
pp. 106 ◽  
Author(s):  
Sergey Ostapchenko ◽  
Marcus Bleicher
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Strong Increase ◽  
Momentum Fraction ◽  
Proton Proton ◽  
High Energies ◽  
Model Predictions ◽  
Potential Impact ◽  
Very High

Steep rise of parton densities in the limit of small parton momentum fraction x poses a challenge for describing the observed energy-dependence of the total and inelastic proton-proton cross sections σ p p tot / inel : considering a realistic parton spatial distribution, one obtains a too-strong increase of σ p p tot / inel in the limit of very high energies. We discuss various mechanisms which allow one to tame such a rise, paying special attention to the role of parton-parton correlations. In addition, we investigate a potential impact on model predictions for σ p p tot, related to dynamical higher twist corrections to parton-production processes.

scholarly journals Laboratory data on atomic spectra for extreme ultra-violet solar spectroscopy

1965 ◽  
Vol 23 ◽  
pp. 25-26 ◽  
Author(s):  
B. Edlén
Keyword(s):  
Relative Abundance ◽  
A Priori ◽  
Laboratory Data ◽  
Solar Spectrum ◽  
Ultra Violet ◽  
Laboratory Work ◽  
Atomic Systems ◽  
The Third ◽  
Order Of Magnitude ◽  
Very High

Expected relative prominence of elements and ionization stages is estimated from existing recordings of the solar XUV spectrum. The following 3 groups of elements, apart from H and He, need be considered : (C, N, O), (Ne, Mg, Si, Fe), (Na, Al, S, Ar, Ca, Ni), the relative abundance descending by approximately an order of magnitude from one group to the next, and all other elements being at least another order of magnitude less abundant. Lines of low and medium stages of ionization are expected only from most abundant elements. The observed presence in the solar spectrum of lines from the neon-like Fe XVII suggests that very high stages of ionization must not be a priori excluded.These considerations indicate that a discussion of laboratory data may be confined to atomic systems containing from 1 to 18 electrons. Observed data on these 18 isoelectronic sequences, and the possibilities of their extrapolation, are reviewed. It is concluded that required data for the first 10 sequences are well in hand, but considerable laboratory work remains to be done on the third-period sequences.A comprehensive paper is being prepared for later publication.

UNDERSTANDING THE NATURE OF PROTON–AIR CROSS-SECTIONS AT VERY HIGH ENERGIES AND THE IMPLICATIONS

2001 ◽  
Vol 16 (37) ◽  
pp. 2387-2397 ◽  
Author(s):  
BHASKAR DE ◽  
S. BHATTACHARYYA ◽  
P. GUPTAROY
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Cross Section Data ◽  
Section Data ◽  
High Energies ◽  
Production Models ◽  
Simulation Based ◽  
Effective Role ◽  
Very High

The purpose of this paper is to focus on the possible effective role of two relatively less-known models in analyzing comprehensively the very up-to-date data on proton–air inelastic cross-sections at high and ultra high energies. The standard versions of all the familiar simulation-based multiparticle production models, which nowadays normally claim front-ranking positions, address on the contrary, only a small part of the cross-section data for a very limited or sectional range of energy values. Against this background, the relevance and impact of the present study have finally been highlighted.

scholarly journals Studying the thinning Effect of Longitudinal development in Extensive Air Showers for Primary Proton and Iron Nuclei at Ultra-High Energies

2020 ◽  
Vol 31 (3) ◽  
pp. 114
Author(s):  
Abbas R. Raham ◽  
Ahmed A. Al-Rubaiee ◽  
Majida H. Al-Kubaisy ◽  
Suror N. Esmaeel
Keyword(s):  
Charged Particles ◽  
Cosmic Ray ◽  
Primary Energy ◽  
Extensive Air Showers ◽  
Primary Proton ◽  
Air Showers ◽  
Longitudinal Development ◽  
High Energies ◽  
Charged Pions ◽  
Very High

In the present work, extensive air showers (EAS) effects are described by estimating the longitudinal development model of EAS at very high energies of various cosmic ray particles. The longitudinal development was simulated for charged particles such as gamma, charged pions and charged muons at very high energies 1017, 1018 and 1019eV. The simulation was performed using an air shower simulator system (AIRES) version 19.04.0. The effect of primary particles, energies, thinning energy and zenith angle (θ) on the number of charged particles (longitudinal development) produced in the EAS was taken into account. The rapprochement of the estimated longitudinal development of the charged particles such as the charged muons and charged pions with the experimental measurements (AUGER experiment) that gave a good agreement for primary proton at the fixed primary energy 1019eV for θ =0˚.

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