Device and method for optimizing diffusion section of electron beam

Patent metadata

Field	Value
Publication number	US-9767985-B2
Application number	US-201414895708-A
Country	US
Kind code	B2
Filing date	Oct 17, 2014
Priority date	Sep 15, 2014
Publication date	Sep 19, 2017
Grant date	Sep 19, 2017

Abstract

Provided is a device for optimizing a diffusion section of an electron beam, comprising two groups of permanent magnets, a magnetic field formed by the four magnetic poles extending the electron beam in a longitudinal direction, and compressing the electron beam in a transverse direction, so that the electron beam becomes an approximate ellipse; another magnetic field formed by the eight magnetic poles optimizing an edge of a dispersed electron-beam bunch into an approximate rectangle; by controlling the four longitudinal connection mechanisms so that the upper magnetic yoke and the lower magnetic yoke of the first group of permanent magnets move synchronously towards the center thereof thereby longitudinally compressing the electron beam in the shape of an approximate ellipse, and the upper magnetic yoke and the lower magnetic yoke of the second group of permanent magnets move synchronously towards the center thereof thereby longitudinally compressing the electron beam in the shape of an approximate rectangle, and the process of longitudinal compression is repeated until a longitudinal size of the electron-beam bunch is reduced to 80 mm. The invention is capable of reasonably compressing a longitudinal size of an electron-beam bunch after diffusion to approximately 80 mm, which ensures optimum irradiation uniformity and efficiency, and enables the longitudinal size to be within the range of a conventional titanium window.

First claim

What is claimed is:

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; and
a 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, and
the 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; and
a locking mechanism configured to fix said distance between said first group of permanent magnets and said second group of permanent magnets,
the method com

Assignees

• Univ Huazhong Science Tech

Inventors

• Huang Jiang
• Fan Mingwu
• Yu Tiaoqin
• Zhang Lige
• Zuo Chen
• Yang Jun
• Xiong Yongqian
• Liu Kaifeng
• Wu Gerald F
• Cao Lei

Classifications

• G21K1/093 Primary

  by magnetic means · CPC title

• H01J2237/152

  Magnetic means · CPC title

• H01J2237/1405

  Constructional details · CPC title

• G21K5/04

  with beam-forming means · CPC title

• H01J37/143 Primary

  Permanent magnetic lenses · CPC title