Patent ID: 9399147
Filing Date: 2016-07-26
CPC Classification: A61N,G21F

Claim Text:
1. A particle beam irradiation chamber in which a passage having a first opening part at the side of an inner wall and a second opening part at the side of an outer wall is provided, an isocenter is provided inside the particle beam irradiation chamber, wherein a first line segment which connects the center of the first opening part and the center of the second opening part does not intersect two side walls constituting the passage, when a vector which starts from the isocenter to the center of the first opening part is designated as a first vector and a vector which starts from the center of the first opening part to the center of the second opening part is designated as a second vector, a component of the first vector which is parallel to a line segment which connects both ends of the first opening part and a component of the second vector which is parallel to a line segment which connects both ends of the first opening are in an opposite direction, and θ is an angle larger than 0 degree and smaller than 90 degrees and is an angle which satisfies (a*sin θ+b*cos θ−t)cos θ>b−t, where a is a length of a perpendicular line which starts from the isocenter to a straight line E which connects both ends of the first opening part, b is a length of a perpendicular line which starts from the isocenter to a straight line F which is perpendicular to the straight line E, and passes a point which is farther away from the isocenter among points of both ends of the first opening part, t is a width of the passage, and θ is an angle which is formed by the straight line F and inner wall of the passage.