Method for replacing plasma generating unit in negative ion source device and negative ion source device

摘要

PROBLEM TO BE SOLVED: To provide a negative ion source device which allows the replacement of a plasma generating part to be rapidly performed in a simple and handy manner.SOLUTION: A negative ion source device 100 comprises: a chamber 108 with a through-hole 108e provided therein; a gas-supply source 122 for supplying a material gas and an inert gas into the chamber 108; a plasma generating part 112 provided in the through-hole 108e for generating plasma by using the material gas supplied by the gas-supply source 122; a cesium supply source 118 for promoting the production of negative ions, and supplying cesium having reactivity with atmospheric air into the chamber 108; and a safety valve 126 for making control so that the pressure of the inert gas supplied into the chamber 108 from the gas-supply source 122 becomes higher than the pressure outside the chamber 108 on condition that the plasma generating part 112 is dismounted from the through-hole 108e.