摘要:

A nonstationary nonlinear theory of electron-wave interaction has been developed for microwave resonant generators. The system of the integro-differential equations determining the amplitude and phase of the excited oscillations in the high Q-resonant system is obtained. For most cases the solutions of the non-stationary nonlinear interaction equations have been found numerically. However, in certain cases such as in the linear region and in the steady-state of the excited oscillations analytical treatments are developed. Transient performances of the radiation of the electron beam and the estimates for the starting current and the amplitude of the stationary oscillations are presented. The application of the obtained equations for the generator pulse is discussed. The solution for the equation of motion is solved and the oscillation period of the electrons in the wave field is determined analytically.

ISSN:0033-7579    

DOI:10.1080/00337577808233156

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

The axial and planar channeling of 1.6 MeV He in α-Al2O3crystals has been studied at room temperature. The experimental results have been compared with the theoretical evaluation following Gemmell-Mikkelson generalization of Barrett's formulas and the Varelas-Sizmann treatment. The agreement between experimental and theoretical results is good if the distortion of the oxygen sublattice, typical of the corundum structure, is taken into account by a simple procedure.

ISSN:0033-7579    

DOI:10.1080/00337577808233157

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

The methods due to Bloch and Pines have been used to calculate the energy loss of channeled protons. The contribution from the various atomic shells to the stopping power is assumed to be additive. The collective effects in a solid plasma produced by the valence electrons are calculated disregarding the band structure. The nonuniform distribution of valence electrons across the channel is taken into account. In contrast to Robinson and Dettmann, a detailed summation is performed over the spectrum of oscillator strengths when calculating the energy loss due to inner-shell electrons.

ISSN:0033-7579    

DOI:10.1080/00337577808233158

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

High-purity Cu specimens doped by electron irradiation with interstitial clusters and single vacancies were annealed isochronally through the temperature range of stage II-1V. After each step of the annealing program, the doped samples received an additional small test irradiation at 4 K followed by an anneal at 65 K. By measuring the fraction,P, of the test interstitials which survived this anneal, reactions of the mobile test interstitials with the doping defects were studied. A substantial increase ofPwas observed as the doping defects were annealed through stage III. A similar increase was found in the 70 K damage production. These increases are attributed to the clustering of doping vacancies in stage HI and can, therefore, be taken as evidence for vacancy migration in this stage.

ISSN:0033-7579    

DOI:10.1080/00337577808233159

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Radiation effects in alpha quartz irradiated with fast neutrons have been studied by using a photoelastic modulator. A search for large size amorphous regions in the irradiated quartz was made. The result does not provide positive evidence for the existence of these structures. These findings were explained by using a model suggested by Primak.

ISSN:0033-7579    

DOI:10.1080/00337577808233160

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

The trapping of irradiation-produced defects by solute atoms in Mg crystals was monitored by measuring the displacement of the solute atoms from lattice sites using the backscattering-channeling technique. In Mg-0.2 at.% Ag crystals, irradiation at 30 K with 1 MeV He+ions resulted in a very large fraction of Ag atoms being displaced from their lattice sites. The Ag atom displacement appeared to be along (4043) directions and is attributed to the trapping of migrating Mg interstitial atoms by Ag atoms to form Mg-Ag mixed dumbbells. Recovery of the Ag atom displacements and the irradiation-induced dechanneling increment occurred principally in two stages, 80-160 K (stage III) and 200-280 K (Stage IV). Stage III is attributed mainly to some type of interstitial migration and stage IV is attributed to the migration of single vacancies. In contrast to the Mg-Ag results, a very small displaced fraction of Bi atoms occurred in an irradiated Mg-0.08 at% Bi crystal; hence Mg-Bi mixed dumbbells do not appear to be formed.

ISSN:0033-7579    

DOI:10.1080/00337577808233161

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

A fission track technique was employed to study the sputtering of uranium by1H+,4He+, and40Ar+ions with energies up to 120 keV. The technique involves detection of fission tracks produced in mica by235U sputtered onto collector foils which are subsequently irradiated with thermal neutrons. This method is extremely sensitive and allowed measurement of sputtering yields less than 10−4atoms per ion. It also made possible a detailed study of the emission of chunks from the uranium targets during sputtering. Mass distributions of chunks emitted during bombardment by 40-120 keV protons and by 80 keV argon are presented. Angular distributions of sputtered material and total sputtering yields for uranium metal under bombardment by 13-120 keV protons and by 40-120 keV4He+are also presented. Sputtering yields for 40 and 80 keV40Ar+were measured as well. Comparisons are made between the experimental results and those predicted by the collision cascade model.

ISSN:0033-7579    

DOI:10.1080/00337577808233162

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Volume 12—Part A: Astrophysics. Optical and Infrared, by N. Carleton, ed. Academic Press, New Yorkl 1974.

ISSN:0033-7579    

DOI:10.1080/00337577808233163

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor