Abstract: The present invention uses as a detector for adjustment measurement, monodyne interference between a microwave for plasma generation and the reflected wave. Analysis of the interference wave that is obtained using monodyne interference allows finding of the phase difference between the incident and the reflected wave and the amplitude of that reflected wave; and controlling of an excited microwave generation/control system based on them allows impedance matching between the excited microwave and the plasma. This method allows very high precision phase detection, and calculation of the characteristics of the plasma based on the detected phase shift. Therefore, it is possible to distinguish noises even in the vicinity of the matched region.

Abstract: A gas decomposition/separation device 100 is made up of three sections: a discharge section 110, a compression section 130, and a separation section 140. The discharge section 110 is a section for decomposing gas through discharging. The discharge section 110 is made up of a discharging electrode 120 and a flange pipe 112 that accommodates it.

Abstract: A continuous or a long-pulsed microwave oscillated from a microwave oscillator 1 is propagated in a waveguided tube 2 in which a given gas is charged. Subsequently, by irradiating a laser having a given intensity from a laser source 4 to the points, A and B in the tube 2, the given gas is partially made plasma. Just then, the microwave can not travel beyond the plasma-part of the given gas and reflects thereat. Accordingly, the microwave is divided at the plasma-part and thereby, a short-pulsed microwave can be obtained.