THE LOSS OF FREE ELECTRONS IN IRRADIATED AIR

1963 ◽  
Vol 41 (4) ◽  
pp. 625-631 ◽  
Author(s):  
B. G. Young ◽  
A. W. Johnson ◽  
J. A. Carruthers
Keyword(s):  
High Pressures ◽  
Irradiation Time ◽  
High Energy ◽  
Free Electrons ◽  
Loss Mechanism ◽  
High Energy Electrons ◽  
Ion Recombination ◽  
Three Body ◽  
Microwave Probe ◽  
Low Pressures

The loss of free electrons in air, nitrogen, and oxygen is studied as a function of pressure by continuously irradiating the gases with high-energy electrons and measuring the equilibrium electron densities with a microwave probe. At low pressures (1–10 mm Hg) electrons are lost by free diffusion to the chamber walls before cooling. At intermediate pressures (10–100 mm Hg) electrons cool rapidly without loss to thermal energy and then disappear by three-body attachment in air and oxygen, and by electron–ion recombination in nitrogen. At high pressures (100–1000 mm Hg) the electron density increases with irradiation time and the controlling loss mechanism is uncertain.

Nonstoichiometry and Chemical Diffusion in Co3O4 Cobalt Oxide

2015 ◽  
Vol 227 ◽  
pp. 421-424
Author(s):  
Zbigniew Grzesik ◽  
Anna Kaczmarska ◽  
Stanisław Mrowec
Keyword(s):  
Oxygen Pressure ◽  
High Pressures ◽  
Chemical Diffusion ◽  
Chemical Diffusion Coefficient ◽  
Low Oxygen ◽  
Free Electrons ◽  
Kinetic Rate ◽  
Deviation From Stoichiometry ◽  
Electron Holes ◽  
Low Pressures

Nonstoichiometry and chemical diffusion in Co3O4oxide have been studied as a function of temperature (973-1173 K) and oxygen pressure (30-105Pa), using thermogravimetric techniques. It has been found that at very low oxygen pressures, close to the dissociation pressure of the oxide, interstitial cations and quasi-free electrons are the predominant point defects, while at high pressures cation vacancies and electron holes predominate. This behaviour is reflected in complex dependence of the deviation from stoichiometry, y, in the Co3±yO4oxide on oxygen pressure. At low pressures, namely, deviation from stoichiometry decreases with increasing oxygen pressure, reaching virtually constant value in intermediate pressures and increases at highest pressure range. Finally, these data as well as the results of kinetic rate measurements of Co3±yO4formation have been utilized in calculating the chemical diffusion coefficient as a function of temperature.

Duration of energy storage following a discharge in xenon

1970 ◽  
Vol 48 (15) ◽  
pp. 1817-1829 ◽  
Author(s):  
P. R. Timpson ◽  
J. M. Anderson
Keyword(s):  
Diffusion Coefficient ◽  
Energy Storage ◽  
Metastable State ◽  
Exponential Decay ◽  
Resonance Line ◽  
High Pressures ◽  
Ambipolar Diffusion ◽  
Ion Recombination ◽  
Low Pressures ◽  
Positive Ion

It has been shown that the afterglow following a discharge in xenon consists of two parts: (1) the resonance line, whose intensity initially decays exponentially in agreement with Holstein's theory; (2) an accompanying distributed radiation, experimentally a continuum, extending to about 1900 a.u. The intensity of this continuum decays exponentially at the same rate as the population of the lower metastable state at all wavelengths and each pressure studied. All departures from an exponential decay seem to be caused by repopulation of states by ionic recombination and are current dependent. Electron disappearance is due to ambipolar diffusion at low pressures and ion recombination at high pressures. The value of the ambipolar diffusion coefficient indicates that the afterglow positive ion is Xe2+ for pressures greater than 0.3 Torr. No phenomena which could be due to interchange of population between metastable states have been found in xenon.

The kinetics and chemistry of the interaction of alkyl radicals. I. The disproportionation and combination of ethyl radicals

1956 ◽  
Vol 236 (1206) ◽  
pp. 318-332 ◽  
Keyword(s):  
Reaction Mechanisms ◽  
High Pressures ◽  
Excess Energy ◽  
Alkyl Radicals ◽  
Products Of Reaction ◽  
Three Body ◽  
Low Pressures ◽  
Ethyl Radicals

The combination and disproportionation of ethyl radicals has been studied over a range of pressures and under various conditions designed to separate the various reaction mechanisms which can occur. It is shown that in addition to the normal two-body reaction, a three-body reaction is important at high pressures, while at low pressures wall reactions become prominent. An interesting feature is the effect on the combination/disproportionation ratio of radicals formed with excess energy which retain that excess long enough so that the subsequent reactions are modified. It is suggested that these alternative reaction mechanisms are responsible for the variety of results reported in the literature for the products of reaction of ethyl radicals.

Untersuchungen am Elektronenstrahlplasma

1966 ◽  
Vol 21 (12) ◽  
pp. 2033-2039 ◽  
Author(s):  
Winfried Herrmann
Keyword(s):  
Beam Energy ◽  
Critical Pressure ◽  
High Pressures ◽  
Essential Feature ◽  
High Energy ◽  
Quiescent State ◽  
Neutral Gas ◽  
A Value ◽  
Hybrid Frequency ◽  
Low Pressures

The beam plasma exists in at least two states: The “quiescent” state with low pressures and the "turbulent" state with high pressures of the neutral gas (argon in most experiments). The quiescent state is described theoretically. It is shown that the system should transport growing waves with frequencies just below the upper hybrid frequency ωH2=ωp2+ωc2. These oscillations are found experimentally for ωp > k1 ωc, where k1 has a value of about 0.35 in the experiments described. Increasing the pressure and the plasma density as well raises the amplitude of the oscillations. Then at the critical pressure the turbulent state with high density is produced very abruptly. The essential feature of this second state is the high energy loss of the beam particles. The dependence of the losses on the parameters of the system is studied in detail. The maximum losses may attain 50% of the original beam energy. Some other properties of the system are described.

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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