| AVS 58th Annual International Symposium and Exhibition | |
| Plasma Science and Technology Division | Thursday Sessions |
| Session PS-ThP |
| Session: | Plasma Science and Technology Poster Session |
| Presenter: | Byung-Keun Na, Korea Advanced Institute of Science and Technology, Republic of Korea |
| Authors: | B.K. Na, Korea Advanced Institute of Science and Technology, Republic of Korea K.H. You, Korea Advanced Institute of Science and Technology, Republic of Korea D.W. Kim, Korea Advanced Institute of Science and Technology, Republic of Korea S.J. You, Korea Research Institute of Standards and Science, Republic of Korea S.H. Seo, Korea Advanced Institute of Science and Technology, Republic of Korea H.Y. Chang, Korea Advanced Institute of Science and Technology, Republic of Korea |
| Correspondent: | Click to Email |
Wave-cutoff method is an electron density measurement tool. Most of the diagnostic tools, including cutoff probe, need a few seconds to measure the plasma parameters. In this presentation, a fast measurement method using Fourier analysis will be newly introduced. A wave-cutoff probe system consists of two antennas and a network analyzer. A network analyzer provides the transmission spectrum and the reflection spectrum by frequency sweeping. The plasma parameters such as electron density can be obtained through these spectra. The frequency sweeping time, the time resolution of the wave-cutoff method, is about 1~10 seconds.
We proposed a new method to use an impulse generator and an oscilloscope instead of a network analyzer. This method was named 'Fourier cutoff probe method'. A short impulse signal with a few GHz band and its transmitted signal were detected by an oscilloscope, and the Fourier analysis of the signals made a transmission spectra of plasma. The data acquisition time can be reduced with this method.
In this work, 3 diagnostic methods, Langmuir probe, network analyzer cutoff probe, and Fourier cutoff probe, were also compared. The measurement results were well matched. This method provides electron density with time resolution of 10 nano seconds, and it took about 100 milli seconds to make a measurement. This technique is found to be very useful especially in pulsed plasma. Fourier cutoff probe was 40 times faster than Langmuir probe in a pulsed plasma measurement.