Experimental investigation of electron gun with nanostructured carbon cathode

2006 ◽  
Author(s):  
A.G. Chakhovskoi ◽  
A.V. Galdetskiy ◽  
A.N. Obraztsov ◽  
A.P. Volkov
Keyword(s):  
Experimental Investigation ◽  
Electron Gun ◽  
Nanostructured Carbon ◽  
Carbon Cathode

scholarly journals Improved Field Emission Properties of Carbon Nanostructures by Laser Surface Engineering

Nanomaterials ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1931
Author(s):  
Minh Nhat Dang ◽  
Minh Dang Nguyen ◽  
Nguyen Khac Hiep ◽  
Phan Ngoc Hong ◽  
In Hyung Baek ◽  
...  
Keyword(s):  
Field Emission ◽  
Edge Effect ◽  
Carbon Nanostructures ◽  
Surface Engineering ◽  
Nanostructured Carbon ◽  
Carbon Cathode ◽  
Electron Sources ◽  
Field Emission Properties ◽  
Turn On ◽  
New Type

We herein present an alternative geometry of nanostructured carbon cathode capable of obtaining a low turn-on field, and both stable and high current densities. This cathode geometry consisted of a micro-hollow array on planar carbon nanostructures engineered by femtosecond laser. The micro-hollow geometry provides a larger edge area for achieving a lower turn-on field of 0.70 V/µm, a sustainable current of approximately 2 mA (about 112 mA/cm2) at an applied field of less than 2 V/µm. The electric field in the vicinity of the hollow array (rim edge) is enhanced due to the edge effect, that is key to improving field emission performance. The edge effect of the micro-hollow cathode is confirmed by numerical calculation. This new type of nanostructured carbon cathode geometry can be promisingly applied for high intensity and compact electron sources.

Experimental investigation of a 1 kA/cm2 sheet beam plasma cathode electron gun

2015 ◽  
Vol 86 (1) ◽  
pp. 013503 ◽  
Author(s):  
Niraj Kumar ◽  
Udit Narayan Pal ◽  
Dharmendra Kumar Pal ◽  
Rahul Prajesh ◽  
Ram Prakash
Keyword(s):  
Experimental Investigation ◽  
Electron Gun ◽  
Plasma Cathode ◽  
Beam Plasma

Experimental Investigation of Boiling Heat Transfer and Pressure Drop in Swirl Flow Under Conditions of One-Sided Heating

2010 ◽  
Author(s):  
Alexander T. Komov ◽  
Alexey V. Dedov ◽  
Alexander N. Varava ◽  
Victor V. Yagov
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Experimental Investigation ◽  
Pressure Drop ◽  
Boiling Heat Transfer ◽  
Nucleate Boiling ◽  
Swirl Flow ◽  
Heat Fluxes ◽  
Electron Gun ◽  
Nucleate Boiling Heat Transfer

The paper gives the basic results of experimental investigation of hydrodynamics and nucleate boiling heat transfer in heat-absorbing devices of the ITER thermonuclear reactor, which are subjected to one-sided heating. Experimental data are obtained on pressure drop, heat transfer and critical heat fluxes (CHF) in the following range of parameters of water flow: pressure p = 0.7–2.0 MPa, mass flux G = 340–25 000 kg/(m2s), and water temperature at the inlet Tin = 20–60 °C. The investigations were performed for flow swirled by tapes with different values of flow swirl coefficient, as well for test sections without tape. The test-sections with a cooled channel of 2.0, 4.0, and 8.0 mm inside diameter were used. One-sided heating of the test sections were provided by the scanning electron beam injected by the electron gun. More than 500 experimental points on nucleate boiling heat transfer were obtained. The predicting equation for nucleate boiling heat transfer at one-sided heating has been proposed. A simple approach was used for the calculation of CHF. The predicting equation for CHF reliably generalizes the existing experimental data.

A High Performance Energy Analyzer for Use in Electron Scanning Microscopy

1969 ◽  
Vol 27 ◽  
pp. 14-15
Author(s):  
A. V. Crewe ◽  
M. Isaacson ◽  
D. Johnson
Keyword(s):  
High Performance ◽  
Vertical Plane ◽  
Median Plane ◽  
Electron Gun ◽  
Uniform Field ◽  
Loss Mechanism ◽  
Electron Scanning Microscopy ◽  
Sector Type ◽  
Double Focusing ◽  
Electron Energy Loss

A double focusing magnetic spectrometer has been constructed for use with a field emission electron gun scanning microscope in order to study the electron energy loss mechanism in thin specimens. It is of the uniform field sector type with curved pole pieces. The shape of the pole pieces is determined by requiring that all particles be focused to a point at the image slit (point 1). The resultant shape gives perfect focusing in the median plane (Fig. 1) and first order focusing in the vertical plane (Fig. 2).

Observation of Phase Contrast Images in STEM and CTEM Modes by Using 100 kV Field Emission Electron Gun

1974 ◽  
Vol 32 ◽  
pp. 390-391
Author(s):  
Y. Harada ◽  
T. Goto ◽  
H. Koike ◽  
T. Someya
Keyword(s):  
Field Emission ◽  
Phase Contrast ◽  
Image Formation ◽  
Fresnel Diffraction ◽  
Experimental Results ◽  
Electron Gun ◽  
Scanning Microscopy ◽  
Emission Electron ◽  
Lattice Images

Since phase contrasts of STEM images, that is, Fresnel diffraction fringes or lattice images, manifest themselves in field emission scanning microscopy, the mechanism for image formation in the STEM mode has been investigated and compared with that in CTEM mode, resulting in the theory of reciprocity. It reveals that contrast in STEM images exhibits the same properties as contrast in CTEM images. However, it appears that the validity of the reciprocity theory, especially on the details of phase contrast, has not yet been fully proven by the experiments. In this work, we shall investigate the phase contrast images obtained in both the STEM and CTEM modes of a field emission microscope (100kV), and evaluate the validity of the reciprocity theory by comparing the experimental results.

Structure and migration of planar defects in crystals observed in atomic scale

1978 ◽  
Vol 36 (1) ◽  
pp. 284-285 ◽  
Author(s):  
H. Hashimoto ◽  
Y. Sugimoto ◽  
Y. Takai ◽  
H. Endoh
Keyword(s):  
Electron Microscope ◽  
Rotation Angle ◽  
Crystal Surface ◽  
Electron Gun ◽  
Atomic Scale ◽  
Present Observation ◽  
Twist Boundary ◽  
Optical Magnification ◽  
Zinc Crystal ◽  
And Migration

As was demonstrated by the present authors that atomic structure of simple crystal can be photographed by the conventional 100 kV electron microscope adjusted at “aberration free focus (AFF)” condition. In order to operate the microscope at AFF condition effectively, highly stabilized electron beams with small energy spread and small beam divergence are necessary. In the present observation, a 120 kV electron microscope with LaB6 electron gun was used. The most of the images were taken with the direct electron optical magnification of 1.3 million times and then magnified photographically.1. Twist boundary of ZnSFig. 1 is the image of wurtzite single crystal with twist boundary grown on the surface of zinc crystal by the reaction of sulphur vapour of 1540 Torr at 500°C. Crystal surface is parallel to (00.1) plane and electron beam is incident along the axis normal to the crystal surface. In the twist boundary there is a dislocation net work between two perfect crystals with a certain rotation angle.

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