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Pseudospark (PS) discharge is promising source for high brightness and high intensity electron beam pulses. In the present paper, an effort has been made to analyse the temporal behaviour of discharge current, applied voltage, plasma density in the PS discharge based PCE-Gun at different hollow cathode aperture sizes using 3-D particle-in-cell (PIC) simulation code "VORPAL". The peak discharge current in the PS discharge is a function of hollow cathode dimensions. The plasma generation process by self ionization discharge is examined at different operating conditions. Argon is taken as the background neutral gas. It has been observed that the decrease in the aperture size from 8 mm to 3 mm increases the discharge current, the electron confinement time and the plasma density. © 2015, National Institute of Science Communication and Information Resources (NISCAIR). All rights reserved.

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Indian Journal of Pure and Applied Physics

Particle-in-cell simulation study of PCE-gun for different hollow cathode aperture sizes

This paper presents the experimental studies on self-breakdown-based single-gap plasma cathode electron (PCE) gun (5-20 kV/50-160 A) in argon, gas atmosphere and its performance evaluation based on particle-in-cell (PIC) simulation code OOPIC-Pro. The PCE-Gun works in conducting phase (low energy, high current) of pseudospark discharge. It produces an intense electron beam, which can propagate more than 200 mm in the drift space region without external magnetic field. The profile of this beam in the drift space region at different breakdown conditions (i.e., gas pressures and applied voltages) has been studied and the experimental results are compared with simulated values. It is demonstrated that30% beam current is lost during the propagation possibly due to space charge neutralization and collisions with neutral particles and walls. © Indian Academy of Sciences.

Pramana - Journal of Physics

Performance evaluation of self-breakdown-based single-gap plasma cathode electron gun

A plasma cathode electron (PCE) gun has capabilities for generating high-current, broad, and focused beams for plasma-assisted microwave sources. A pseudospark-based hollow cathode PCE gun has been designed and developed for microwave generation which is operated in argon atmosphere. An analysis of the electron beam profile inside the drift space at different operating conditions has been carried out. This has been performed at several axial and radial locations inside the drift space which shows coherent phases of beam profiles in radial direction. The focusing and defocusing points in axial direction are also obtained. The beam current at different axial location for different applied voltages has been estimated. The obtained beam current is in close agreement with the beam current estimated by the particle-in-cell simulation code for the same geometry.

Fulltext

Journal of Theoretical and Applied Physics

Development of low-pressure high-current plasma cathode electron gun and use of associated techniques

Electron beam analysis of pseudospark sourced electron gun

Pseudospark discharge based plasma cathode has capability to provide high current density electron beam during discharge process. In this paper an effort has been made to simulate the breakdown processes in the pseudospark discharge based plasma cathode electron gun. The two-dimensional plasma simulation codes VORPAL and OOPIC-Pro have been used and results are compared. The peak discharge current in the plasma cathode electron gun is found to be dependent on aperture size, hollow cathode dimensions, anode voltage and seed electrons energy. The effect of these design parameters on the peak anode current has been analysed by both the codes and results matches well within 10% variation. For the seed electron generation an electron beam trigger source is used to control the discharge process in the hollow cathode cavity. The time span of trigger source has been varied from 1-100 ns to analyze the effect on the peak anode current. © Published under licence by IOP Publishing Ltd.

Journal of Physics: Conference Series

Comparative simulation studies of plasma cathode electron (PCE) gun

In this paper, the development of large volume double ring Penning plasma discharge source for efficient light emissions is reported. The developed Penning discharge source consists of two cylindrical end cathodes of stainless steel having radius 6 cm and a gap 5.5 cm between them, which are fitted in the top and bottom flanges of the vacuum chamber. Two stainless steel anode rings with thickness 0.4 cm and inner diameters 6.45 cm having separation 2 cm are kept at the discharge centre. Neodymium (Nd2Fe14B) permanent magnets are physically inserted behind the cathodes for producing nearly uniform magnetic field of ∼0.1 T at the center. Experiments and simulations have been performed for single and double anode ring configurations using helium gas discharge, which infer that double ring configuration gives better light emissions in the large volume Penning plasma discharge arrangement. The optical emission spectroscopy measurements are used to complement the observations. The spectral line-ratio technique is utilized to determine the electron plasma density. The estimated electron plasma density in double ring plasma configuration is ∼2 × 1011 cm-3, which is around one order of magnitude larger than that of single ring arrangement. © 2012 American Institute of Physics.

Review of Scientific Instruments

Development of large volume double ring penning plasma discharge source for efficient light emissions

This paper presents experimental studies for the production and propagation of an electron beam from a single gap pseudospark discharge based plasma cathode electron (PCE) gun. The generated electron beam has been successfully propagated for more than 25 cm in a gaseous environment without application of external guiding magnetic field at different operating conditions. The electron beam losses due to recombination with ions and collision with walls of drift space have been estimated. The electron beam profile has also been analyzed in the drift region of the gun. © Published under licence by IOP Publishing Ltd.

Investigation of electron beam parameters inside the drift region of plasma cathode electron gun

The pseudospark (PS) discharge is, however, more recently recognized as a different type of discharge which is capable of generating electron beams with the highest combined current density and brightness of any known type of electron source. PS discharge is a specific type of gas discharge, which operates on the left-hand side of the hollow cathode analogy to the Paschen curve with axially symmetric parallel electrodes and central holes on the electrodes. The PS discharge generated electron beam has tremendous applications in plasma filled microwave sources where normal material cathode cannot be used. Analysis of the electron beam profile has been carried out experimentally for different applied voltages. The investigation has been done at different axial and radial location inside the drift tube in argon atmosphere. This paper represents experimentally derived axial and radial variation of the beam current inside the plasma filled drift tube of PS discharge based plasma cathode electron (PCE) gun. With the help of current density estimation the focusing and defocusing point of electron beam in axial direction can be analyzed. It has been further confirmed the successful propagation of electron beam in confined manner without any assistance of external magnetic field.

Experimental investigation of pseudospark generated electron beam

The pseudospark (PS) discharge has been shown to be a promising source of high brightness, high intensity electron beam pulses. The PS discharge sourced electron beam has potential applications in plasma filled microwave sources where normal material cathode cannot be used. Analysis of the electron beam profile has been done experimentally for different applied voltages. The investigation has been carried out at different axial and radial location inside the drift space in argon atmosphere. This paper represents experimentally found axial and radial variation of the beam current inside the drift tube of PS discharge based plasma cathode electron (PCE) gun. With the help of current density estimation the focusing and defocusing point of electron beam in axial direction can be analyzed. © 2011 Springer Science+Business Media, LLC.

Journal of Infrared, Millimeter, and Terahertz Waves

Experimental analysis of Pseudospark sourced electron beam

Photoconductive Antennas (PCA) are widely used for terahertz (THz) generation and detection. These PCAs build the basis for future 6G communication as they provide a high data rate and broad bandwidth. In this work, interdigitated photoconductive antenna (IPCA) has been designed and optimized for better performance in terms of THz radiation. The proposed IPCA is made of LT-GaAs substrate material deposited on SI-GaAs. Silver material has been assumed for the IPCA electrode structure. Moreover, the dependence of IPCA on the incident laser parameters such as its wavelength (λ&nbsp;=&nbsp;800, 1060, and 1550 nm) and pulse duration (100–500 fs) has been investigated theoretically for different teeth widths (We&nbsp;=&nbsp;500, 100, 50, and 20 nm). The performance of the IPCA with various parameters such as average carrier density, conductance, total photocurrent, THz radiated power, and electric field strength, has been analyzed. The results show maximum THz electric field strength of 20.85 V/m for a photo-generated current of 1.887 A and enormous bandwidth beyond 14.9 THz with 20 nm teeth-width-based IPCA when illuminated with 100 fs 800 nm laser pulses. The proposed IPCA structure provides enhanced THz radiation compared to conventional PCA. This investigation helps the researchers to develop and integrate IPCA for future wireless communications as well as for a variety of applications, such as time-domain spectroscopy (THz-TDS), medical imaging, sensing, and security-related applications.