Apparatuses and methods for generating distributed x-rays

Patent metadata

Field	Value
Publication number	US-9786465-B2
Application number	US-201314136362-A
Country	US
Kind code	B2
Filing date	Dec 20, 2013
Priority date	Dec 27, 2012
Publication date	Oct 10, 2017
Grant date	Oct 10, 2017

Abstract

An apparatus and method to generate distributed x-rays. A hot cathode of an electron gun is used in vacuum to generate electron beams having certain initial movement energy and speed. Periodic scanning is performed with the initial low-energy electron beams, which are thus caused to be reciprocally deflected. A current-limiting device is provided in the travel path of the electron beams along the direction of the reciprocal deflection. Through holes arranged in an array on the current-limiting device, only part of the electron beams targeting specific positions can pass to form sequential electron beam currents distributed in an array. These electron beam currents are accelerated by a high-voltage electric field to obtain high energy, bombard an anode target, and thus sequentially generate corresponding focus spots and x-rays distributed in an array at the anode target.

First claim

What is claimed is:

1. An apparatus to generate distributed x-rays, the apparatus comprising:
an electron gun configured to generate electron beam currents;
a scanning device configured to generate a scanning magnetic field to deflect the electron beam currents;
a current-limiting device having a plurality of regularly-arranged holes, wherein lines extending along sectional surfaces of respective holes of the current-limiting device and in the deflection direction of the electron beam currents, intersect at a central portion of the scanning magnetic field;
a control system configured to control the scanning device to scan the electron beam currents relative to the current-limiting device such that a central portion of the electron beam currents becomes incident on an opaque portion of the current-limiting device between at least two of the holes and such that, when the electron beam currents scan through the holes of the current-limiting device, pulsed electron beams corresponding to positions of the holes in the scanning order are outputted in an array beneath the current-limiting device; and
an anode target arranged downstream of the current-limiting device, wherein an electric field is formed between the current-limiting device and the anode target to accelerate the array of the pulsed electron beams, and wherein the accelerated electron beams bombard the anode target to generate x-rays.

2. The apparatus of claim 1 , further comprising a vacuum box provided downstream of the electron gun, coupled with the electron gun, and enclosing the current-limiting device and the anode target, the vacuum box configured to provide a high vacuum environment for generation and movement of electron beams.

3. The apparatus of claim 2 , further comprising a power and control device configured to provide power supply and operation control to the electron gun, the scanning device and the anode target.

4. The apparatus of claim 3 , wherein the current-limiting device comprises a strip-shaped metal plate having a plurality of holes.

5. The apparatus of claim 3 , further comprising a plug-pull high-voltage connection device at a lower side of the vacuum box, the plug-pull high-voltage connection device coupled with the anode target inside the vacuum box, extending outside the vacuum box, and configured to directly connect the power and control device with the anode target.

6. The apparatus of claim 2 , further comprising a focusing device at a position where the electron gun is coupled with the vacuum box, the focusing device configured to focus the electron beam currents and reduce a beam spot of the electron beam currents.

7. The apparatus of claim 2 , further comprising a vacuum device on the vacuum box, the vacuum device configured to maintain high vacuum inside the vacuum box.

8. The apparatus of claim 7 , wherein the vacuum device comprises a vacuum ion pump.

9. The apparatus of claim 2 , further comprising a shielding and collimation device outside the vacuum box, the shielding and collimation device comprising a strip-shaped collimation opening corresponding to the anode target.

10. The apparatus of claim 9 , wherein the shielding and collimation device is made of leaded material.

11. The apparatus of claim 1 , wherein the anode target comprises a strip-shaped metal plate having a length substantially identical to that of the current-limiting device.

12. The apparatus of claim 11 , wherein the anode target is made of tungstenic material.

13. The apparatus of claim 1 , wherein the anode target is parallel to the current-limiting device in a length direction, and at a small angle with respect to the current-limiting device in a width direction.

14. A method of generating distributed x-rays, the method comprising:
controlling an electron gun to generate electron beam currents;
controlling a scanning device to generate a scanning magnetic field for deflecting the electron beam currents relative to a current-limiting device such that a central portion of the electron beam currents becomes incident on an opaque portion of the current-limiting device between at least two of a plurality of holes regularly arranged on the current-limiting device and such that the electron beam currents scan through the holes to output pulsed electron beams distributed in an array, wherein lines extending along sectional surfaces of respective holes of the current-limiting device and in the deflection direction of the electron beam currents, intersect at a central portion of the scanning magnetic field; and
generating an electric field between the current-limiting device and an anode target to accelerate the pulsed electron beams distributed in the array, the accelerated electron beams bombarding the anode target to generate x-rays.

15. The method of claim 14 , wherein the current-limiting device comprises a strip-shaped metal plate having a plurality of holes.

16. The method of claim 14 , wherein the anode target comprises a strip-shaped metal plate having a length substantially identical to that of the current-limiting device.

17. The method of claim 14 , further comprising providing a high vacuum environment for generation and movement of electron beams in a vacuum box provided downstream of the electron gun, the vacuum box coupled with the electron gun and enclosing the current-limiting device and the anode target.

18. The method of claim 14 , wherein the anode target is parallel to the current-limiting device in a length direction, and at a small angle with respect to the current-limiting device in a width direction.

19. The method of claim 14 , further comprising using a focusing device to focus the electron beam currents and reduce a beam spot of the electron beam currents.

20. The method of claim 14 , further comprising using a shielding and collimation device to shield unwanted x-rays and to constrain the desired x-rays within a desired application range using a strip-shaped collimation opening corresponding to the anode target.

Assignees

• Univ Tsinghua
• Nuctech Co Ltd

Inventors

• Li Yuanjing
• Liu Yaohong
• Liu Jinsheng
• Tang Huaping
• Tang Chuanxiang
• Chen Huaibi
• Yan Xinshui

Classifications

• H01J35/30 Primary

  by deflection of the cathode ray · CPC title

• H01J2235/16

  Vessels · CPC title

• H01J35/14 Primary

  Arrangements for concentrating, focusing, or directing the cathode ray · CPC title

• H01J35/153 Primary

  Spot position control · CPC title

• H01J35/045

  Electrodes for controlling the current of the cathode ray, e.g. control grids · CPC title