Patent Number: 
Section: claims

1. A collector comprising:a first mirror shell positioned inside a second mirror shell that has a chamfered end. 2. The collector of claim 1, wherein said collector receives light from a light source and reflects said light to illuminate an area in a plane. 3. The collector of claim 2, wherein said chamfered end receives said light from said light source. 4. The collector of claim 1,wherein said second mirror shell includes a portion that receives light and reflects said light, andwherein said chamfered end receives said light from said portion, and further reflects said light. 5. The collector of claim 1, wherein said second mirror shell has a thickness that decreases in a direction of said chamfered end. 6. The collector of claim 1,wherein said first mirror shell receives light from a light source at an angle of incidence of less than 20° to a surface tangent of said first mirror shell, andwherein said second mirror shell receives light from said light source at an angle of incidence of less than 20° to a surface tangent of said second mirror shell. 7. The collector of claim 1, wherein at least one of said first and second mirror shells includes a first segment having a first optical surface and second segment having a second optical surface. 8. The collector of claim 7,wherein said first segment is annular in a section of a hyperboloid, andwherein said second segment is annular in a section of an ellipsoid. 9. The collector of claim 7,wherein said first segment is annular in a section of a hyperboloid, andwherein said second segment is annular in a section of a paraboloid. 10. An illumination system comprising:a light source;a plane; anda collector that receives light from said light source, and illuminates an area in said plane,wherein said collector has a first mirror shell positioned inside a second mirror shell that has a chamfered end. 11. The illumination system of claim 10, further comprising an optical element having a plurality of raster elements in a light path from said light source to said plane. 12. The illumination system of claim 11,wherein said collector illuminates an annular region in said plane, andwherein said plurality of raster elements are in said annular region. 13. An EUV-projection exposure facility comprising:the illumination system of claim 10 for illuminating a mask; anda projection objective for imaging said mask onto a light sensitive object. 14. A method of manufacturing a micro-electronic component, comprising using the EUV-projection exposure facility of claim 13.