Effect of cathode materials on the generation of runaway electron beams and X-rays in atmospheric pressure air
| Autor: | Tao Shao, Ping Yan, Alexander G. Burachenko, Cheng Zhang, Evgeni Kh. Baksht, Igor' D. Kostyray, Victor F. Tarasenko |
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| Rok vydání: | 2013 |
| Předmět: | |
| Zdroj: | Laser and Particle Beams. 31:353-364 |
| ISSN: | 1469-803X 0263-0346 |
| Popis: | In this work, experiments were performed to study the effect of cathode materials on the amplitude of the super-shortavalanche electron beam (SAEB) current and X-ray density during discharges in atmospheric-pressure air. In theexperiments, discharges were generated by three nanosecond-pulse generators in air gaps between a plane anode and atubular cathode made of different metals. The output pulse of the three generators had a rise time of 0.3, 1, 15 ns, anda full width at half maximum of 1, 2, 30–40 ns, respectively. For the generators with pulse rise-time of 0.3 and 1 ns,the cathodes used in these experiments were made of stainless steel, permalloy, titanium, niobium, copper, brass, andaluminum. For the generator with pulse rise-time of 15 ns, the cathodes were made of stainless steel, titanium, copper,and aluminum. When the rise time of the applied pulse is 0.3 ns, our experimental results show that the amplitude ofthe voltage across the gap depends on the cathode material and reaches its maximum value when a stainless steelcathode is used. It is also observed that, under such situation, the maximum amplitudes of the SAEB current occur atmaximum voltages across the gap when all other factors are equal. Furthermore, the amplitude of the SAEB currenthereof is found to depend not only on the material of the sharp edge of the tubular cathode, but also on the material ofthe side surface of the tubular cathode. When the rise time of the applied pulse is 1 ns, the experimental results showthat the average number of electrons in SAEB is also affected by the cathode materials. In addition, in the case that therise time of the voltage pulse is 15 ns and the gap spacing is 8 cm, the experimental results show that the cathodematerial has no effect on the voltage amplitude across the gap and the X-ray density. The increase of the pulserepetition frequency from 250 to 500 Hz under such condition can lead to a three-fold increase in X-ray density in arepetitive pulsed mode.Keywords: Air diffuse discharge; Cathode material; Nanosecond pulse; Super-short avalanche electron beam;X-ray density |
| Databáze: | OpenAIRE |
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