scholarly journals Space-Charge Limitation of a Femtosecond Photoinjector

2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
Hiroko Yamamoto ◽  
Hiroaki Hamabe ◽  
Shintaro Sone ◽  
Soichiro Yamaguchi ◽  
Makoto R. Asakawa
Keyword(s):  
Experimental Investigation ◽  
Space Charge ◽  
Current Density ◽  
Cathode Surface ◽  
Laser Pulses ◽  
Space Charge Limited Current ◽  
Electron Bunches ◽  
Surface Field ◽  
Simple Physical Model ◽  
Fs Laser

Experimental investigation of a compact 40-kV diode-type photoelectric DC gun driven by 100 fs laser pulses revealed that the space-charge-limited current density could exceed 30 kA/cm2and that the density increased linearly with the accelerating voltage. We explained these important properties by the balance between the cathode surface field and the field produced by sheet-like electron bunches near the cathode surface. Our simple physical model agreed well with the experimental results.

Generation of Quasimonoenergetic Electron Bunches with 80-fs Laser Pulses

2006 ◽  
Vol 96 (10) ◽  
Author(s):  
B. Hidding ◽  
K.-U. Amthor ◽  
B. Liesfeld ◽  
H. Schwoerer ◽  
S. Karsch ◽  
...  
Keyword(s):  
Laser Pulses ◽  
Electron Bunches ◽  
Fs Laser

RESTORATION OF MACHINE PARTS WITH GALVANIZED ZINC COATINGS

2020 ◽  
Vol 4 (141) ◽  
pp. 140-147
Author(s):  
MIKHAIL VIKHAREV ◽  
◽  
VLADIMIR YUDIN ◽  
VESELOVSKIY NIKOLAY ◽  
◽  
...  
Keyword(s):  
Current Density ◽  
Cathode Surface ◽  
Zinc Coating ◽  
Cathode Current Density ◽  
Research Purpose ◽  
Cathode Layer ◽  
Properties Of Coatings ◽  
Chemical Polarization ◽  
Cathode Current ◽  
Zinc Coatings

The article shows the role of electroplating in the restoration of parts, indicates the advantages of restoring parts with electroplating over other methods, and gives the characteristics and properties of coatings obtained by electroplating. (Research purpose) The research purpose is in increasing the speed of application of zinc electroplating when restoring parts. (Materials and methods) The cathode current density has a decisive influence on the coating speed. The main reason for limiting the cathode current density during galvanizing from sulfuric acid electrolytes is the chemical polarization of the cathode. The article presents a study on the designed installation for the application of galvanic coatings. When applying coatings to the internal surfaces of parts, there was used a device with activating elements having an electromechanical rotation drive. This device prevents depletion of the near-cathode layer of the electrolyte and reduces the chemical polarization of the cathode. Elements made of moisture-resistant skin were used as activators. (Results and discussion) The article presents the results of experiments as a dependence of the coating speed on the speed of the activator relative to the restoring surface. It also presents the relationship between the size of the abrasive grains of the activating elements, the force of their pressing against the cathode surface, the speed of movement of the activator and the speed of applying the zinc coating, as well as its quality. By activating the cathode surface, it was possible to raise the operating current density to 100-150 amperes per square decimeter. The speed of application of zinc coatings is 16-25 micrometers per minute. (Conclusions) In the course of research, authors determined the conditions of electrolysis during galvanizing, which provide a significant increase in the cathode current density and the rate of application of these coatings during the restoration of parts.

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