Nec Corporation

Tetsu Mieno

Keizo Kinoshita

Seiji Samukawa

In a mass spectrometer, a DC power supply amplifier is additionally provided in a circuit for generating an accelerating voltage of an electron beam for ionizing radicals. A 'potential for ionization of radicals' is applied as a reference voltage of the accelerating voltage of the radical ionizing electron beam, and an output signal of the mass spectrometer is measured as a background signal strength. Then, the DC power supply amplifier is controlled to alternately supply the 'potential for ionization of radicals' and a 'potential slightly lower than a potential for dissociative ionization of parent gas or dissociative ionization of parent radicals', as the accelerating voltage of the radical ionizing electron beam. A difference between the background signal strength and the output signal of the mass spectrometer when the 'potential slightly lower than a potential for dissociative ionization of parent gas or dissociative ionization of parent radicals' is applied as the accelerating voltage of the radical ionizing electron beam, reflects the density of radicals.

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Shizuoka, Japan

Tetsu Mieno