JPS6463300A - High frequency acceleration cavity - Google Patents

Abstract

PURPOSE:To restrain multipactoring discharge and enable the supply of rated electric power without any consideration of aging and an operational problem by equipping a side plate for supporting a pair of acceleration electrodes, and outer casing with both edges thereof covered by said side plate and a solenoid coil positioned outside the outer casing, respectively in a high frequency acceleration cavity used in an accelerator for the fine processing of VLSI circuits and the like. CONSTITUTION:A solenoid coil 14 is positioned outside an antenna 4. The solenoid 14 is so sized as to have a diameter larger than the flange outer diameter of an antenna port 4a, in order to enable the easy assembly and further the dismantling thereof whenever necessary such as in the parking of an acceleration cavity and the like. The solenoid coil 14 is supported with a coil support frame 15 and this frame 15 is bolted to an outer casing 1. Among the magnetic field components of the solenoid coil 14, the components parallel to the axes of antenna inner and outer conductors 9 and 10 are B. On the other hand, the distribution of a magnetic field E is radial. It follows, therefore, that even if a secondary electron is emitted due to the collision of a primary electron, the secondary electron is subjected to a force in a circumferential direction and made to curve without straight advance to an opposite surface. As a result, a frequency wherein an electron resiprocates between the inner and outer conductors 9 and 10, becomes different from the frequency of a high frequency electric field and multipactoring discharge can be thereby restrained.