scholarly journals Test of a High-gradient Low-emittance Electron Gun

1997 ◽  
Vol 15 (3) ◽  
pp. 427-447 ◽  
Author(s):  
F. Villa ◽  
F. Villa ◽  
A. Luccio
Keyword(s):  
Electric Field ◽  
Beam Current ◽  
Electron Gun ◽  
Electron Current ◽  
Beam Emittance ◽  
High Gradient ◽  
Large Current ◽  
Theoretical Predictions ◽  
Maximum Electric Field ◽  
Low Emittance

A maximum electric field E = 2.65 GV/m with an accelerated electron current of 1 KA has been obtained, for pulse lengths of 130 ps, in an electron gun based on Pulse Power Technology. This is the highest accelerating field ever achieved in the presence of such a large current. Measurements of beam emittance and energy from 0.4 to 2.65 MeV show that the scaling of the invariant emittance with electric field and with beam current is consistent with theoretical predictions. A few applications of high-gradient acceleration are discussed.

A Study on Physically Based Maximum Electric Field Modeling Used for HCI Induced Degradation Characteristic of LDMOS

2019 ◽  
Vol 888 ◽  
pp. 89-95
Author(s):  
Nobukazu Tsukiji ◽  
Hitoshi Aoki ◽  
Haruo Kobayashi
Keyword(s):  
Electric Field ◽  
Field Model ◽  
High Current ◽  
Field Modeling ◽  
Large Current ◽  
Physically Based ◽  
Degradation Characteristic ◽  
Maximum Electric Field ◽  
Injection Effect ◽  
Gate Edge

This paper describes a physically based maximum electric field model of laterally diffused MOSFET (LDMOS) transistors under the condition of high current injection effect used for reliability and aging simulations. LDMOSFETs work under high-voltage and large-current biases, where electric field increases with the biases at the gate edge. We present formulations, implementations into SPICE simulators and measurement verifications of our physically based maximum electric field model.

scholarly journals Analysis of Electric Field and Current Density for Different Electrode Configuration of XLPE Insulation

2018 ◽  
Vol 7 (3.36) ◽  
pp. 127 ◽  
Author(s):  
Nishanthi Sunthrasakaran ◽  
Nor Akmal Mohd Jamail ◽  
Qamarul Ezani Kamarudin ◽  
Sujeetha Gunabalan
Keyword(s):  
Electric Field ◽  
Power System ◽  
Field Distribution ◽  
High Voltage ◽  
Current Density ◽  
Electric Field Distribution ◽  
Electrical Power ◽  
High Electric Field ◽  
Electrode Configuration ◽  
Maximum Electric Field

The most important aspect influencing the circumstance and characteristics of electrical discharges is the distribution of electric field in the gap of electrodes. The study of discharge performance requires details on the variation of maximum electric field around the electrode. In electrical power system, the insulation of high voltage power system usually subjected with high electric field. The high electric field causes the degradation performance of insulation and electrical breakdown start to occur. Generally, the standard sphere gaps widely used for protective device in electrical power equipment. This project is study about the electric field distribution and current density for different electrode configuration with XLPE barrier. Hence, the different electrode configuration influences the electric field distribution. This project mainly involves the simulation in order to evaluate the maximum electric field for different electrode configuration. Finite Element Method (FEM) software has been used in this project to perform the simulation. This project also discusses the breakdown characteristics of the XLPE. The accurate evaluation of electric field distribution and maximum electric field is an essential for the determination of discharge behavior of high voltage apparatus and components. The degree of uniformity is very low for pointed rod-plane when compared to other two electrode configurations. The non- uniform electric distribution creates electrical stress within the surface of dielectric barrier. As a conclusion, when the gap distance between the electrodes increase the electric field decrease.  

ON OPTIMUM PUPIL FIELDS WITH MAXIMUM ELECTRIC FIELD COMPONENT IN FOCUS

2010 ◽  
Vol 19 (01) ◽  
pp. 189-201
Author(s):  
H. P. URBACH ◽  
S. F. PEREIRA ◽  
D. J. BROER
Keyword(s):  
Electric Field ◽  
Field Component ◽  
Optical Axis ◽  
Focal Point ◽  
Longitudinal Component ◽  
Electric Field Component ◽  
Incident Power ◽  
Entrance Pupil ◽  
Maximum Electric Field ◽  
High Na Lens

The field in the entrance pupil of a high NA lens can be optimized such that, for given incident power, the electric field component in a given direction in the focal point is maximum. If the field component is chosen parallel to the optical axis, the longitudinal component is maximized and it is found that the optimum longitudinal component is narrower than the Airy spot. We discuss how this can be used to obtain higher resolution in photolithography when a resist is used that is sensitive to only the longitudinal component. We describe a proposition for realizing such resist.

scholarly journals High gradient quadrupoles for low emittance storage rings

2016 ◽  
Vol 19 (5) ◽  
Author(s):  
G. Le Bec ◽  
J. Chavanne ◽  
C. Benabderrahmane ◽  
L. Farvacque ◽  
L. Goirand ◽  
...  
Keyword(s):  
Storage Rings ◽  
High Gradient ◽  
Low Emittance

Deepening of domains at e-beam writing on the -Z surface of lithium niobate

2021 ◽  
Author(s):  
Lyudmila Kokhanchik ◽  
Evgenii Emelin ◽  
Vadim Vladimirovch Sirotkin ◽  
Alexander Svintsov
Keyword(s):  
Surface Layer ◽  
Electron Beam ◽  
Lithium Niobate ◽  
Electric Field ◽  
Domain Walls ◽  
Normal Component ◽  
Beam Current ◽  
Near Surface ◽  
Domain Structures ◽  
Sign Inversion

Abstract The focus of the study was to investigate the peculiarities of the domains created by electron beam (e-beam) in a surface layer of congruent lithium niobate, which comparable to a depth of electron beam charge penetration. Direct e-beam writing (DEBW) of different domain structures with a scanning electron microscope was performed on the polar -Z cut. Accelerating voltage 15 kV and e-beam current 100 pA were applied. Different patterns of local irradiated squares were used to create domain structures and single domains. No domain contrast was observed by the PFM technique. Based on chemical etching, it was found that the vertices of the domains created do not reach the surface level. The average deepening of the domain vertices was several hundred nanometers and varied depending on the irradiation dose and the location of the irradiated areas (squares) relative to each other. Computer simulation was applied to analyze the spatial distribution of the electric field in the various irradiated patterns. The deepening was explained by the fact that in the near-surface layer there is a sign inversion of the normal component of the electric field strength vector, which controls the domain formation during DEBW. Thus, with the help of e-beam, domains were created completely located in the bulk, in contrast to the domains that are nucleated on the surface of the -Z cut during the polarization inversion with AFM tip. The detected deepening of e-beam domains suggests the possibility of creating the “head-to-head” domain walls in the near-surface layer lithium niobate by DEBW.

scholarly journals A numerical model of the ionosphere, including the E-region above EISCAT

1996 ◽  
Vol 14 (2) ◽  
pp. 191-200 ◽  
Author(s):  
P.-Y. Diloy ◽  
A. Robineau ◽  
J. Lilensten ◽  
P.-L. Blelly ◽  
J. Fontanari
Keyword(s):  
Electric Field ◽  
Fluid Model ◽  
Molecular Ions ◽  
Ion Concentration ◽  
Topside Ionosphere ◽  
Ion Chemistry ◽  
Vhf Radar ◽  
Theoretical Predictions ◽  
Consistent Manner ◽  
E Region

Abstract. It has been previously demonstrated that a two-ion (O+ and H+) 8-moment time-dependent fluid model was able to reproduce correctly the ionospheric structure in the altitude range probed by the EISCAT-VHF radar. In the present study, the model is extended down to the E-region where molecular ion chemistry (NO+ and O+2, essentially) prevails over transport; EISCAT-UHF observations confirmed previous theoretical predictions that during events of intense E×B induced convection drifts, molecular ions (mainly NO+) predominate over O+ ions up to altitudes of 300 km. In addition to this extension of the model down to the E-region, the ionization and heating resulting from both solar insolation and particle precipitation is now taken into account in a consistent manner through a complete kinetic transport code. The effects of E×B induced convection drifts on the E- and F-region are presented: the balance between O+ and NO+ ions is drastically affected; the electric field acts to deplete the O+ ion concentration. The [NO+]/[O+] transition altitude varies from 190 km to 320 km as the perpendicular electric field increases from 0 to 100 mV m-1. An interesting additional by-product of the model is that it also predicts the presence of a noticeable fraction of N+ ions in the topside ionosphere in good agreement with Retarding Ion Mass Spectrometer measurements onboard Dynamic Explorer.

Effects of edge biasing on blob dynamics and associated transport in the edge of the J-TEXT tokamak

2022 ◽  
Author(s):  
Wei Li ◽  
Yuhong Xu ◽  
Jun Cheng ◽  
Hai Liu ◽  
Zhipeng Chen ◽  
...  
Keyword(s):  
Electric Field ◽  
Large Scale ◽  
Turbulent Transport ◽  
Radial Electric Field ◽  
Plasma Confinement ◽  
Flow Shear ◽  
Theoretical Predictions ◽  
Outward Motion ◽  
Electrode Biasing ◽  
Particle Confinement

Abstract Effects of edge radial electric field Er and Er × B flow shear on edge turbulence and turbulent transport, in particular, on large-scale blobs and blobby transport have been investigated in the positive and negative biasing discharges in the J-TEXT tokamak. The results show that under certain conditions, the positive electrode biasing induces better plasma confinement than the negative biasing. Further studies reveal that in addition to flow shear effects on blob dynamics, the local radial electric field at the edge region plays a significant role in repulsion of the blobs and associated transport, leading to improvement of particle confinement when the outward motion of the blobs is blocked. The results are in accordance with theoretical predictions.

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