Patent Number: 
Section: claims

1. A device for optimizing a diffusion section of an electron beam, comprising:a first group of permanent magnets comprising four magnetic poles fixed on an upper magnetic yoke and a lower magnetic yoke in pairs, a polarity of a magnetic pole being different from that of another magnetic pole adjacent or opposite thereto, a magnetic field formed by the four magnetic poles extending an electron beam in a longitudinal direction and compressing said electron beam in a transverse direction, so that said electron beam becomes an approximate ellipse;a second group of permanent magnets comprising eight magnetic poles fixed on an upper magnetic yoke, a lower magnetic yoke, a left magnetic yoke, and a right magnetic yoke in pairs, a polarity of a magnetic pole being different from that of another magnetic pole adjacent or opposite thereto, a magnetic field formed by the eight magnetic poles optimizing an edge of a dispersed electron-beam bunch into an approximate rectangle;four longitudinal connection mechanisms, both ends of each of said upper magnetic yoke and said lower magnetic yoke of said first group of permanent magnets being respectively disposed on a left magnetic yoke and a right magnetic yoke via two of the four longitudinal connection mechanisms, both ends of each of said upper magnetic yoke and said lower magnetic yoke of said second group of permanent magnets being respectively disposed on said left magnetic yoke and said right magnetic yoke via the other two of the four longitudinal connection mechanisms;a supporting block disposed between respective adjacent magnetic poles on said magnetic yokes of said first and second groups of permanent magnets, the supporting block being configured to prevent said respective adjacent magnetic poles from deviation due to attractive force thereof;four slide mechanisms including slide bars, bases, and bearings, said four slide mechanisms configured to respectively connect four corner points formed by said four magnetic yokes of said first group of permanent magnets with another four corner points formed by said four magnetic yokes of said second group of permanent magnets, said first group of permanent magnets being fixed with respect to said slide bars via the bases, said second group of permanent magnets being movable along said slide bars via the bearings, thereby adjusting a distance between said first group of permanent magnets and said second group of permanent magnets; anda locking mechanism configured to fix said distance between said first group of permanent magnets and said second group of permanent magnets via threaded rods, the threaded rods disposed on both sides of said second group of permanent magnets and operate to connect said first group of permanent magnets to said second group of permanent magnets;wherein said upper magnetic yoke and said lower magnetic yoke of said first group of permanent magnets are configured to move synchronously relative to both said left and right magnetic yokes of said first group of permanent magnets towards a center between said upper magnetic yoke and said lower magnetic yoke of said first group of permanent magnets via longitudinal connection mechanisms, and thereby longitudinally compressing said electron beam in a shape of an approximate ellipse,said upper magnetic yoke and said lower magnetic yoke of said second group of permanent magnets are configured to move synchronously relative to both said left and right magnetic yokes of said second group of permanent magnets towards a center between said upper magnetic yoke and said lower magnetic yoke of said second group of permanent magnets via longitudinal connection mechanisms, and thereby longitudinally compressing said electron beam in a shape of an approximate rectangle, andthe first group and the second group of permanent magnets are configured to reduce said electron-beam bunch to 80 mm via the four longitudinal mechanism and the four slide bars. 2. The device for optimizing a diffusion section of an electron beam of claim 1, wherein said longitudinal connection mechanisms are facilitated by: an upper strip-form through hole and a lower strip-form through hole are disposed on said left magnetic yoke or said right magnetic yoke, and operate to respectively receive one end of each of said upper magnetic yoke and said lower magnetic yoke via screws, and calibration is labeled on the wall of said through holes, and allows determination of positions of said upper magnetic yoke and said lower magnetic yoke via a vernier caliper. 3. The device for optimizing a diffusion section of an electron beam of claim 1, further comprising a groove, wherein the groove is disposed at the surface of said magnetic yoke, and interference fit with one end of said magnetic pole for receiving said magnetic pole, said groove being fixed by attractive force between said magnetic pole and said magnetic yoke, and via a fixed mount made of aluminum alloy. 4. The device for optimizing a diffusion section of an electron beam of claim 3, further comprising a pad disposed between said groove and said magnetic pole. 5. A method for optimizing a diffusion section of an electron beam using a device for optimizing a diffusion section of an electron beam, wherein the device comprising:a first group of permanent magnets comprising four magnetic poles fixed on an upper magnetic yoke and a lower magnetic yoke in pairs, a polarity of a magnetic pole being different from that of another magnetic pole adjacent or opposite thereto, a magnetic field formed by the four magnetic poles extending an electron beam in a longitudinal direction and compressing said electron beam in a transverse direction, so that said electron beam becomes an approximate ellipse;a second group of permanent magnets comprising eight magnetic poles fixed on an upper magnetic yoke, a lower magnetic yoke, a left magnetic yoke, and a right magnetic yoke in pairs, a polarity of a magnetic pole being different from that of another magnetic pole adjacent or opposite thereto, a magnetic field formed by the eight magnetic poles optimizing an edge of a dispersed electron-beam bunch into an approximate rectangle;four longitudinal connection mechanisms, both ends of each of said upper magnetic yoke and said lower magnetic yoke of said first group of permanent magnets being respectively disposed on a left magnetic yoke and a right magnetic yoke via two of the four longitudinal connection mechanisms, both ends of each of said upper magnetic yoke and said lower magnetic yoke of said second group of permanent magnets being respectively disposed on said left magnetic yoke and said right magnetic yoke via the other two of the four longitudinal connection mechanisms;a supporting block disposed between respective adjacent magnetic poles on said magnetic yokes of said first and second groups of permanent magnets, the supporting block being configured to prevent said respective adjacent magnetic poles from deviation due to attractive force thereof;four slide mechanisms including slide bars, bases, and bearings, said four slide mechanisms configured to respectively connect four corner points formed by said four magnetic yokes of said first group of permanent magnets with another four corner points formed by said four magnetic yokes of said second group of permanent magnets, said first group of permanent magnets being fixed with respect to said slide bars via said bases, said second group of permanent magnets being movable along said slide bars via said bearings, thereby adjusting a distance between said first group of permanent magnets and said second group of permanent magnets; anda locking mechanism configured to fix said distance between said first group of permanent magnets and said second group of permanent magnets,the method comprising:conducting a first longitudinal compression to compress an electron beam in a shape of an approximate ellipse by moving said upper magnetic yoke and said lower magnetic yoke of said first group of permanent magnets synchronously relative to both said left and right magnetic yokes of said first group of permanent magnets towards a center between said upper magnetic yoke and said lower magnetic yoke of said first group of permanent magnets;conducting a second longitudinal compression to compress said electron beam in a shape of an approximate rectangle by moving said upper magnetic yoke and said lower magnetic yoke of said second group of permanent magnets synchronously relative to both said left and right magnetic yokes of said second group of permanent magnets towards a center between said upper magnetic yoke and said lower magnetic yoke of said second group of permanent magnets; andrepeating the first and the second longitudinal compression until a longitudinal size of said electron beam is reduced to 80 mm.