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Measurement of electron emission from a plasma focus
Author
Tan, Li Ching
Supervisor
Lee, Paul Choon Keat
Abstract
The objective of this project is to measure and hence increase our understanding of the electron emission from the National Institute of Education - Natural Sciences Academic Group - Plasma Focus Facility (NIE-NSAG-PFF).
For this purpose, a magnetic electron spectrum analyser was designed and built. Electron trajectory simulation softwares were employed to determine the optimum layout inside the analyser, to calibrate and calculate the energetic error of the detector, to investigate the effect of the presence of Neon gas in the analyser, and to calculate the sensitivity variations arising from the deposition of energy in the Silicon layer in the charged coupled device detector. Each of the 159 spectra signals recorded from the analyser was then processed in exactly the same manner in order to ensure the uniformity and reliability of the results.
The design of the analyser proved to be superior to others, especially in the detection of electrons with energy in the range of 30 to 150 keV. As such, a new phenomenon - multiple peak discharges - was observed, and further analysis of the trend of the energies resulted in the formulation of a mathematical relationship between the energies at the various peaks. Two electron acceleration mechanisms were also proposed to account for the dependence. In addition, a voltage probe was designed and built especially to measure the voltage across the plasma column. The time response of the probe was exceptionally fast and the probe was found to be excellent for measurements up to 45 kV. Highly Collimated Beams and Poorly Collimated Beams were both observed, affirming other reports of their existence. Results from studies of energy at peak signals and operating pressure indicate that the plasma focus has the potential to be a tuneable electron source.
For this purpose, a magnetic electron spectrum analyser was designed and built. Electron trajectory simulation softwares were employed to determine the optimum layout inside the analyser, to calibrate and calculate the energetic error of the detector, to investigate the effect of the presence of Neon gas in the analyser, and to calculate the sensitivity variations arising from the deposition of energy in the Silicon layer in the charged coupled device detector. Each of the 159 spectra signals recorded from the analyser was then processed in exactly the same manner in order to ensure the uniformity and reliability of the results.
The design of the analyser proved to be superior to others, especially in the detection of electrons with energy in the range of 30 to 150 keV. As such, a new phenomenon - multiple peak discharges - was observed, and further analysis of the trend of the energies resulted in the formulation of a mathematical relationship between the energies at the various peaks. Two electron acceleration mechanisms were also proposed to account for the dependence. In addition, a voltage probe was designed and built especially to measure the voltage across the plasma column. The time response of the probe was exceptionally fast and the probe was found to be excellent for measurements up to 45 kV. Highly Collimated Beams and Poorly Collimated Beams were both observed, affirming other reports of their existence. Results from studies of energy at peak signals and operating pressure indicate that the plasma focus has the potential to be a tuneable electron source.
Date Issued
2002
Call Number
QC718.4 Tan
Date Submitted
2002