New type of combined bipole deflector for a rf glow discharge ion source
Tong L., Cui Z., Mao F.
In order to reduce the disturbances produced by photoradiation and neutral particles in an RF glow discharge ion source used in a sputtered neutral mass spectrometer, a new type of combined dipole deflector has been developed, which consists of semicylindrical electrodes and diaphragms with eccentric apertures. A theoretical analysis and experiments have been carried out. It has been shown that the photoradiation background can be reduced by six orders of magnitude with the eccentric structure. The ion beam is extracted with double deflection and focused laterally by the semicylindrical dipoles, which results in a high ion transmission up to 20%. This deflector is suitable for coupling a plasma type of ion source with a quadrupole mass spectrometer and has an extremely high signal to noise ratio.