Wyniki wyszukiwania - BazTech

1

Photoelectron emission and its instrumental effect on optogalvanic measurements in a hollow cathode discharge

Zhechev D., Bundaleska N., Costello J. T., Todorov D.

Opto-Electronics Review

|

2005

|

Vol. 13, No. 3

193-196

EN

The photoelectron emission (PE) from the cathode surface of a hollow cathode discharge (HCD) with a sub-breakdown bias applied, and hence no discharge present, was measured within the framework of an optogalvanic (OG) experimental arrangement. The work function dependence on the applied sub-breakdown voltage was investigated. The PE component in a real OG measurement was found to manifest itself as an instrumental effect together with nonresonant ionization which we call here space ionization (SP). The convolution of these components was determined experimentally as an instrumental function. A deconvolution procedure to determine the actual OG signal was developed.

2

Excitation space anisotropy, coherence and coherent conductivity in hollow cathode discharge

Zhechev D., Parvanova N.

Opto-Electronics Review

|

2003

|

Vol. 11, No. 1

51-54

EN

Based on the excitation space anisotropy a partial polarisation of the spontaneous emission is found in hollow cathode discharge. This polarisation is ascribed to existing spontaneous coherence, i. e., self-alignment of the excited states. The aligning factors are the beam-like fast electrons from the cathode dark space. An expression for observed signal of the spontaneous emission magnetic depolarisation is obtained. Withim the frames of the ordinary opto-galvanic effect a separate coherent conductivity is analysed. a poor coherent conductivity due the self-aligned states is detected.

3

Anomalous optogalvanic signal : spectrometric applications

Zhechev D., Parvanova N.

Opto-Electronics Review

|

2003

|

Vol. 11, No. 1

31-34

EN

Along with the conventional optogalvanic (OG) signal an anomalous ligh-induced response has been detected in hollow cathode discharge. This response manifests itself both in the amplitude and time-resolved OG reactions. The anomalous OG signal is found to be less dependent on the absorbing optical transition and yet, more informative on the parameters of the plasma medium, that is the OG detector. This circumstance is proposed for usage in four applications based on the behaviour of the anomalous OG signal. The latter is taken as a spectral marker, as an amplified quasi-amplitude signal as well as a sensitive tool in monitoring procedure.

4

A hollow cathode discharge modification as a of sputtered atoms and their ions

Zhechev D., Tileva S., Mishinsky G. V., Zhemenik V. I.

Opto-Electronics Review

|

2001

|

Vol. 9, No. 4

419-422

EN

A nonconvectional hollow cathode discharge (HCD) modification grounded on a conical bottom (CB) cylindrical cathode is reported. this CBHCD enhances the main HCD property, i.e., the sputtering of the cathode surface/probe inserted. Comparative polarisation measurements with a conventional flat bottom HCD show a stronger narrowing of the Hanle signal width for the sputtered Cu atoms in CBHCD.This their density is higher in CBHCD. This result is specified by the redial optogalvanic profile. It contains two peaks of the mentioned density, i.e., near the cylindrical cathode surface and over the cone peak. Some preliminary examinations of CBHCD as an ion source in three arrangements are performed and discussed.