Patent ID: 7935944
Filing Date: 2011-05-03
Classification: H01J

Abstract:
1. An ion beam irradiating apparatus which irradiates a target with an ion beam extracted from an ion source, said apparatus comprising: a field emission electron source, which is disposed in a vicinity of a path of the ion beam and which emits electrons to neutralize space charge of the ion beam, said field emission electron source having a conductive cathode substrate, a plurality of minute emitters, which are formed on the conductive cathode substrate and each of which has a pointed shape, and an extraction electrode which surrounds respectively vicinities of tip ends of said emitters with forming a minute gap, wherein said field emission electron source is placed in a direction along which an incident angle formed by electrons emitted from said field emission electron source and a direction parallel to a traveling direction of the ion beam is in a range from −15 deg. to +45 deg., where an inward direction of the ion beam is +, and an outward direction is −, and wherein said electrons emitted from said field emission electron source directly travel into said path of the ion beam without any deflection members guiding said electrons between said electron source and said path of the ion beam.