Development of a 600 joules small plasma focus as pulsed radiation source / Lee Seng Huat
The work starts at developing a 600 joules small plasma focus based on previous experience and works on the 3 kJ plasma focus system [Lee et al. (1988), Favre et al. (1992), Moo et al. (1995), Yap et. al. (2005)]. The objectives of this project are two folds, first, to scale down the energy of th...
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| Format: | Thesis |
| Published: |
2011
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| Online Access: | http://studentsrepo.um.edu.my/3784/1/1._Title_page%2C_abstract%2C_content.pdf http://studentsrepo.um.edu.my/3784/2/2._Chap_1.pdf http://studentsrepo.um.edu.my/3784/3/2._Chap_2.pdf http://studentsrepo.um.edu.my/3784/4/2._Chap_3.pdf http://studentsrepo.um.edu.my/3784/5/2._Chap_4.pdf http://studentsrepo.um.edu.my/3784/6/2._Chap_5.pdf http://studentsrepo.um.edu.my/3784/7/3._References.pdf http://pendeta.um.edu.my/client/default/search/results?qu=Development+of+a+600+joules+small+plasma+focus&te= http://studentsrepo.um.edu.my/3784/ |
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| Summary: | The work starts at developing a 600 joules small plasma focus based on previous
experience and works on the 3 kJ plasma focus system [Lee et al. (1988), Favre et al.
(1992), Moo et al. (1995), Yap et. al. (2005)]. The objectives of this project are two
folds, first, to scale down the energy of the plasma focus device from kJ to few hundred
joules; and second to develop the new system as a pulsed radiation source.
The development and construction of the small Mather type plasma focus
system employed a novel design with electrodes of 60 mm in length and without an
insulator as the conventional plasma focus. The investigation of the discharges is
focused on getting an optimum operating condition for plasma focus with reproducible
radiation emission. Argon gas is used, while the operating pressures are varied to study
the dynamics of the plasma focus as well as the radiation output.
The plasma focus discharges have been investigated by using a Rogowski coil,
resistive voltage divider, X-ray Detector (XRD), EUV detector and biased ion collectors,
for the discharge current, discharge voltage, X-ray radiation output, EUV radiation
output and ion beam output. Suitable condition has been identified at a low pressure
regime of 9.0 × 10-3 mbar to 2.2 × 10-2 mbar of argon. Reproducible results with good
plasma focus and radiation output are obtained. The plasma focus is observed
consistently; with good reproducibility of above 80 % in this pressure range. Radiation
emissions are mainly in the ultra soft X-ray to EUV region. A total EUV energy vary
from 7.8 mJ to 275 mJ is obtained, which corresponds to a conversion efficiency of
0.0013 % to 0.046 %. The ultra-soft radiation and EUV are emitted during the plasma
focus time, where the signals are coincide with the voltage spike. The best condition of focusing discharge is identified to be in a very narrow range of argon pressures of
1.0 - 1.8 × 10-2 mbar. The highest EUV energy output of 275 mJ is also obtained at
about 1.6 × 10-2 mbar. In these pressures, the ion beams observed are relatively low in
intensity. Conversely, the ion beam is found to increase at lower pressures. Energies of
the ion beams measured are calculated based on the time of flight method. Argon ion
beam with energy of 38 keV to 560 keV are obtained. It is also found that
9.0 × 10-3 mbar is the optimum argon pressure for high energetic ion beam production. |
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