MICROWAVE ION SOURCE

PURPOSE:To enable a plastic material to be used so as to prevent the window from being deformed by making thin the thickness of a microwave introducing window, reducing the ratio of a wavelength inside of a thin microwave tube in that part to the thickness of the introducing window so as to reduce the reflection of a microwave and also providing a dielectric substance on the vacuum side of the window. CONSTITUTION:A microwave is propagated through a rectangular waveguide 2 from a microwave generator 1 to enter into a vacuum through a microwave introducing window 3. In that case, the thickness of the window is made thin, and the microwave is entered into a plasma chamber 5 via a rectangular waveguide 4 to produce a strong microwave electric field therein. A dielectric substance 6 is provided within the waveguide 4 to prevent the deformation of the window 3 and abnormal discharge in the other part than the chamber from being produced, and also the vacuum lock of an ion source part is performed by an O-ring 7 placed on the chamber side of the window 3. Further, a solenoid in the periphery and not shown in the figure is provided in the part of the chamber 5 to apply a strong magnetic field in the direction perpendicularly crossing the microwave electric field. Thereby, when a sample gas is entered from a gas introducing tube 8 thereinto, plasma of high density is produced to output a beam 11 from an electrode system 9.