Coupled-channel method for nuclear scattering of Dirac particles: High-energy electrons on calcium

1977 ◽  
Vol 15 (5) ◽  
pp. 1786-1800 ◽  
Author(s):  
Robert L. Mercer
Keyword(s):  
High Energy ◽  
Nuclear Scattering ◽  
Dirac Particles ◽  
High Energy Electrons ◽  
Coupled Channel

scholarly journals The angular distribution of photoelectrons from the K shell

1937 ◽  
Vol 162 (908) ◽  
pp. 95-110 ◽  
Keyword(s):  
Angular Distribution ◽  
High Energy ◽  
X Rays ◽  
Nuclear Scattering ◽  
Uniform Illumination ◽  
Expansion Chamber ◽  
Metal Foils ◽  
High Energy Electrons ◽  
Source Of Error ◽  
Representative Samples

In an investigation with the cloud chamber on the properties of X-rays, Wilson (1923) observed that although photoelectrons due to a narrow pencil of X-rays were ejected from the gas atoms in all directions, there was, especially in the case of high-energy electrons, a preponderance with forward components in their velocities of ejection. Wilson’s pictures threw light on results obtained earlier by workers in X-ray fields, who found an excess of electrons ejected forwards from thin metal foils by X-rays, and have since inspired a number of experiments designed to determine with precision the angular distribution of photoelectrons. A survey of the different methods developed for this purpose has been given by Compton and Allison (1935). Of these the cloud expansion chamber has proved the most satisfactory, in spite of the inevitable disadvantages associated with statistical methods. If a suitable gas is chosen, the shells from which the electrons are ejected can usually be identified, and the directions of ejection can be determined from measurements relating to the initial portions of the cloud tracks. No trouble is ever encountered in distinguishing photoelectron tracks from those due to recoil electrons. The method has been criticized by Watson (1927), who suggested the possibility of nuclear scattering within the radius of the first drop. This objection has been answered by Kirchner (1927), who was able to show from an application of Rutherford’s theory of nuclear scattering to the problem, that under normal conditions of observation the effect of nuclear scattering on the initial directions of ejection as measured from track photographs could be neglected. The most likely source of error appears to lie in the systematic exclusion of tracks in certain angular intervals determined by the experimental arrangement (e. g. positions of cameras, lighting, etc.), and much thought has been given by different workers (Kirchner 1927; Williams, Nuttall and Barlow 1928) as to the best means for ensuring representative samples of tracks for measurement. In this respect our experience leads us to believe that a requirement of fundamental importance is sufficient and uniform illumination throughout the whole chamber.

Nuclear scattering of high energy electrons

1959 ◽  
Vol 12 (2) ◽  
pp. 177-180 ◽  
Author(s):  
E. Predazzi
Keyword(s):  
High Energy ◽  
Nuclear Scattering ◽  
High Energy Electrons

scholarly journals Properties of Elementary Particle Fluxes in Primary Cosmic Rays Measured with the Alpha Magnetic Spectrometer on the International Space Station

2019 ◽  
Vol 209 ◽  
pp. 01007
Author(s):  
Francesco Nozzoli
Keyword(s):  
Electron Flux ◽  
Space Station ◽  
Cosmic Ray ◽  
High Energy ◽  
Precision Measurements ◽  
High Energy Electrons ◽  
Electrons And Positrons ◽  
Positron Flux ◽  
Rigidity Dependence ◽  
Alpha Magnetic Spectrometer

Precision measurements by AMS of the fluxes of cosmic ray positrons, electrons, antiprotons, protons as well as their rations reveal several unexpected and intriguing features. The presented measurements extend the energy range of the previous observations with much increased precision. The new results show that the behavior of positron flux at around 300 GeV is consistent with a new source that produce equal amount of high energy electrons and positrons. In addition, in the absolute rigidity range 60–500 GV, the antiproton, proton, and positron fluxes are found to have nearly identical rigidity dependence and the electron flux exhibits different rigidity dependence.

scholarly journals Polar Middle Atmospheric Responses to Medium Energy Electron (MEE) Precipitation Using Numerical Model Simulations

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 133
Author(s):  
Ji-Hee Lee ◽  
Geonhwa Jee ◽  
Young-Sil Kwak ◽  
Heejin Hwang ◽  
Annika Seppälä ◽  
...  
Keyword(s):  
Climate Model ◽  
Middle Atmosphere ◽  
Meridional Circulation ◽  
Stratospheric Ozone ◽  
High Energy ◽  
Chemical Changes ◽  
Temperature Changes ◽  
Mesospheric Temperature ◽  
High Energy Electrons ◽  
Circulation Changes

Energetic particle precipitation (EPP) is known to be an important source of chemical changes in the polar middle atmosphere in winter. Recent modeling studies further suggest that chemical changes induced by EPP can also cause dynamic changes in the middle atmosphere. In this study, we investigated the atmospheric responses to the precipitation of medium-to-high energy electrons (MEEs) over the period 2005–2013 using the Specific Dynamics Whole Atmosphere Community Climate Model (SD-WACCM). Our results show that the MEE precipitation significantly increases the amounts of NOx and HOx, resulting in mesospheric and stratospheric ozone losses by up to 60% and 25% respectively during polar winter. The MEE-induced ozone loss generally increases the temperature in the lower mesosphere but decreases the temperature in the upper mesosphere with large year-to-year variability, not only by radiative effects but also by adiabatic effects. The adiabatic effects by meridional circulation changes may be dominant for the mesospheric temperature changes. In particular, the meridional circulation changes occasionally act in opposite ways to vary the temperature in terms of height variations, especially at around the solar minimum period with low geomagnetic activity, which cancels out the temperature changes to make the average small in the polar mesosphere for the 9-year period.

The Effects of High-Energy Electrons on the Charging of Spacecraft Dielectrics

1979 ◽  
Vol 26 (6) ◽  
pp. 5101-5106 ◽  
Author(s):  
M. J. Treadaway ◽  
C. E. Mallon ◽  
T. M. Flanagan ◽  
R. Denson ◽  
E. P. Wenaas
Keyword(s):  
High Energy ◽  
High Energy Electrons

scholarly journals Ovaries of Chrysanthemum Irradiated with High-Energy Photons and High-Energy Electrons Can Regenerate Plants with Novel Traits

Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1111
Author(s):  
Natalia Miler ◽  
Iwona Jedrzejczyk ◽  
Seweryn Jakubowski ◽  
Janusz Winiecki
Keyword(s):  
Total Dose ◽  
In Vitro Regeneration ◽  
High Energy ◽  
Mutation Breeding ◽  
Chrysanthemum Morifolium ◽  
Physical Factors ◽  
Strong Impact ◽  
Breeding Method ◽  
High Energy Electrons

Classical mutation breeding using physical factors is a common breeding method for ornamental crops. The aim of our study was to examine the utility of ovaries excised from irradiated inflorescences of Chrysanthemum × morifolium (Ramat.) as explants for breeding purposes. We studied the in vitro regeneration capacity of the ovaries of two chrysanthemum cultivars: ‘Profesor Jerzy’ and ‘Karolina’ preceded by irradiation with high-energy photons (total dose 5, 10 and 15 Gy) and high-energy electrons (total dose 10 Gy). Growth and inflorescence parameters of greenhouse acclimatized regenerants were recorded, and ploidy level was estimated with flow cytometry. The strong impact of genotype on regeneration efficiency was recorded—cultivar ‘Karolina’ produced only 7 viable shoots, while ‘Profesor Jerzy’ produced totally 428 shoots. With an increase of irradiation dose, the regeneration decreased, the least responsive were explants irradiated with 15 Gy high-energy photons and 10 Gy high-energy electrons. Regenerants of ‘Profesor Jerzy’ obtained from these explants possessed shorter stem and flowered later. The highest number of stable, color and shape inflorescence variations were obtained from explants treated with 10 Gy high-energy photons. Variations of inflorescences were predominantly changes of shape—from full to semi-full. New color phenotypes were dark yellow, light yellow and pinkish, among them only the dark yellow phenotype remained stable during second year cultivation. None of the regenerants were haploid. The application of ovaries irradiated within the whole inflorescence of chrysanthemum can be successfully applied in the breeding programs, provided the mother cultivar regenerate in vitro efficiently.

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