High-Current Vacuum Arcs Phenomena at Transmission Voltage Level

There is increasing interest in X-ray microanalysis of thin specimens and the present paper attempts to define some of the factors which govern the spatial resolution of this type of microanalysis. One of these factors is the spreading of the electron probe as it is transmitted through the specimen. There will always be some beam-spreading with small electron probes, because of the inevitable beam divergence associated with small, high current probes; a lower limit to the spatial resolution is thus 2αst where 2αs is the beam divergence and t the specimen thickness.In addition there will of course be beam spreading caused by elastic and inelastic interaction between the electron beam and the specimen. The angle through which electrons are scattered by the various scattering processes can vary from zero to 180° and it is clearly a very complex calculation to determine the effective size of the beam as it propagates through the specimen.

Download Full-text

Precipitation in silicon: Microanalysis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100104431 ◽

1988 ◽

Vol 46 ◽

pp. 474-475

Author(s):

R.W. Carpenter

Keyword(s):

Transition Metals ◽

Spatial Resolution ◽

Thin Foil ◽

Precipitation Reaction ◽

High Current ◽

Reaction Products ◽

Carbon And Nitrogen ◽

Dielectric Layers ◽

Precipitation Processes ◽

Areas Of Interest

Interest in precipitation processes in silicon appears to be centered on transition metals (for intrinsic and extrinsic gettering), and oxygen and carbon in thermally aged materials, and on oxygen, carbon, and nitrogen in ion implanted materials to form buried dielectric layers. A steadily increasing number of applications of microanalysis to these problems are appearing. but still far less than the number of imaging/diffraction investigations. Microanalysis applications appear to be paced by instrumentation development. The precipitation reaction products are small and the presence of carbon is often an important consideration. Small high current probes are important and cryogenic specimen holders are required for consistent suppression of contamination buildup on specimen areas of interest. Focussed probes useful for microanalysis should be in the range of 0.1 to 1nA, and estimates of spatial resolution to be expected for thin foil specimens can be made from the curves shown in Fig. 1.

Download Full-text

Defect reduction in oxygen implanted silicon-on-insulator material during high-temperature annealing

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100154998 ◽

1989 ◽

Vol 47 ◽

pp. 604-605

Author(s):

P. Roitman ◽

B. Cordts ◽

S. Visitserngtrakul ◽

S.J. Krause

Keyword(s):

High Temperature ◽

Annealing Temperature ◽

Silicon On Insulator ◽

High Dose ◽

High Temperature Annealing ◽

High Current ◽

Defect Reduction ◽

Annealing Step ◽

Multiple Cycle ◽

Defect Densities

Synthesis of a thin, buried dielectric layer to form a silicon-on-insulator (SOI) material by high dose oxygen implantation (SIMOX – Separation by IMplanted Oxygen) is becoming an important technology due to the advent of high current (200 mA) oxygen implanters. Recently, reductions in defect densities from 109 cm−2 down to 107 cm−2 or less have been reported. They were achieved with a final high temperature annealing step (1300°C – 1400°C) in conjunction with: a) high temperature implantation or; b) channeling implantation or; c) multiple cycle implantation. However, the processes and conditions for reduction and elimination of precipitates and defects during high temperature annealing are not well understood. In this work we have studied the effect of annealing temperature on defect and precipitate reduction for SIMOX samples which were processed first with high temperature, high current implantation followed by high temperature annealing.

Download Full-text

CONDUCTIVITY MEASUREMENTS OF HIGH CURRENT, HIGH PRESSURE DISCHARGES

Le Journal de Physique Colloques ◽

10.1051/jphyscol:19797149 ◽

1979 ◽

Vol 40 (C7) ◽

pp. C7-303-C7-304

Author(s):

M. Skowronek ◽

L. Giry ◽

Vu Tien Gia ◽

P. Romeas

Keyword(s):

High Pressure ◽

High Current ◽

Conductivity Measurements

Download Full-text

HIGH-CURRENT DIFFUSE DISCHARGE WITH THE EXPLOSIVE CATHODE PROCESS

Le Journal de Physique Colloques ◽

10.1051/jphyscol:19797138 ◽

1979 ◽

Vol 40 (C7) ◽

pp. C7-281-C7-282

Author(s):

A. P. Kchuzeev ◽

Yu. D. Korolev ◽

V. A. Kuzmin ◽

G. A. Mesyats ◽

V. P. Rotshtein ◽

...

Keyword(s):

High Current ◽

Diffuse Discharge ◽

Cathode Process

Download Full-text

Dependence of Current Harmonics of Greenhouse Irradiators on Supply Voltage

Light & Engineering ◽

10.33383/2019-024 ◽

2020 ◽

pp. 85-88 ◽

Cited By ~ 1

Author(s):

Nadezhda P. Kondratieva

Keyword(s):

Mathematical Models ◽

Supply Voltage ◽

Harmonic Distortion ◽

Feasibility Studies ◽

Power Losses ◽

Voltage Level ◽

Supply Networks ◽

Current Harmonics ◽

Cable Lines ◽

Harmonic Composition

The article describes the results of the study concerning the effect of the voltage level on current harmonic composition in greenhouses irradiators. It is found that its change affects the level of current harmonics of all types of the studied greenhouse irradiators. With decrease of nominal supply voltage by 10 %, the total harmonic distortion THDi decreases by 9 % for emitters equipped with high pressure sodium lamps (HPSL), by 10 % for emitters with electrode-less lamps and by 3 % for LED based emitters. With increase of nominal supply voltage by 10 %, THDi increases by 23 % for lighting devices equipped with HPSL, by 10 % for irradiators with electrode-less lamps and by 3 % for LED based emitters. Therefore, changes of supply voltage cause the least effect on the level of current harmonics of LED based emitters and then the emitters with electrode-less lamps. Change of the level of supply voltage causes the greatest effect on the level of current harmonics of HPSL based irradiators. Mathematical models of dependence of THDi on the level of supply voltage for greenhouse emitters equipped with LED, electrode-less lamps and HPSL lamps were formulated. These mathematical models may be used for calculations of total current when selecting transformers and supply cable lines for greenhouse lighting devices, for design of new or reconstruction of existing irradiation systems of greenhouse facilities, and for calculation of power losses in power supply networks of greenhouse facilities during feasibility studies for energy saving and energy efficiency increasing projects.

Download Full-text