Patent Number: 
Section: claims

1. An extreme ultraviolet light generation apparatus comprising:A. a chamber in which extreme ultraviolet light is generated by a target substance being irradiated with a laser beam to generate plasma from the target substance;B. a vessel as a tubular member forming the chamber;C. a reference member supporting the vessel;D. a collector mirror configured to condense the extreme ultraviolet light in the chamber, the collector mirror being attached to the reference member in a replaceable manner and covered by the vessel to be housed in the chamber; andE. a vessel movement mechanism provided to the reference member and configured to move the vessel between a first position at which the vessel covers the collector mirror and a second position at which the vessel is retracted from the first position to expose the collector mirror. 2. The extreme ultraviolet light generation apparatus according to claim 1, wherein, in the reference member, an attachment surface to which the collector mirror is attached is tilted relative to the horizontal direction. 3. The extreme ultraviolet light generation apparatus according to claim 1, further comprising:F. a target sensor provided to the vessel and configured to measure the target substance in the chamber. 4. The extreme ultraviolet light generation apparatus according to claim 1, wherein the vessel movement mechanism includes a link member including a main shaft and a slide member configured to slide relative to the main shaft in the axial direction of the main shaft, one of the main shaft and the slide member being attached to the reference member, the other of the main shaft and the slide member being attached to the vessel, and moves the vessel relative to the reference member through the relative slide of the main shaft and the slide member. 5. The extreme ultraviolet light generation apparatus according to claim 4, wherein the link member is an air cylinder including a piston rod functioning as the main shaft, and a cylinder functioning as the slide member. 6. The extreme ultraviolet light generation apparatus according to claim 4, wherein the link member is a ball screw including a screw shaft functioning as the main shaft, and a nut functioning as the slide member configured to relatively slide in the axial direction of the screw shaft while being engaged with the screw shaft and relatively rotating about the axis of the screw shaft. 7. The extreme ultraviolet light generation apparatus according to claim 4, wherein the vessel movement mechanism includes a drive device configured to drive the link member. 8. The extreme ultraviolet light generation apparatus according to claim 1, wherein the vessel movement mechanism linearly moves the vessel between the first position and the second position. 9. The extreme ultraviolet light generation apparatus according to claim 8, wherein the vessel movement mechanism moves the vessel in the axial direction of the vessel. 10. The extreme ultraviolet light generation apparatus according to claim 8, wherein the vessel movement mechanism slides the vessel in a direction intersecting with the axial direction of the vessel. 11. The extreme ultraviolet light generation apparatus according to claim 1, wherein the vessel movement mechanism rotationally moves the vessel at movement between the first position and the second position. 12. The extreme ultraviolet light generation apparatus according to claim 11, whereinthe vessel is rotatably attached to the reference member through a hinge at one end of the attachment surface, andthe vessel movement mechanism rotationally moves the vessel with the hinge as a pivot. 13. The extreme ultraviolet light generation apparatus according to claim 11, wherein the vessel movement mechanism moves the vessel between the first position and the second position in combination of linear movement and rotational movement. 14. The extreme ultraviolet light generation apparatus according to claim 1, further comprising:G. a positioning mechanism configured to determine a position at which the vessel is attached to the reference member at the second position. 15. The extreme ultraviolet light generation apparatus according to claim 14, wherein the positioning mechanism includes a taper pin having an outer diameter that decreases from a base end side toward a leading end side, and an engagement hole to be engaged with the taper pin, one of the taper pin and the engagement hole being provided to the vessel, the other being provided to the reference member. 16. The extreme ultraviolet light generation apparatus according to claim 14, wherein the positioning mechanism is a ball spline including a spline shaft in which a key groove is formed in the axial direction, and a slider configured to slide relative to the spline shaft along the key groove, one of the spline shaft and the slider being attached to the vessel, the other being attached to the reference member. 17. The extreme ultraviolet light generation apparatus according to claim 1, further comprising:H. an O ring disposed between the attachment surface and an end face of the vessel, which faces the attachment surface at the first position, to seal a gap between the attachment surface and the end face. 18. The extreme ultraviolet light generation apparatus according to claim 17, wherein a ring groove to which the O ring is attached is formed on the attachment surface or the end face. 19. The extreme ultraviolet light generation apparatus according to claim 18, wherein a sectional shape of the attachment groove is a substantially trapezoid shape having a smaller width at an opening than inside the ring groove.