Apparatuses and methods for generating distributed x-rays in a scanning manner

Patent metadata

Field	Value
Publication number	US-9991085-B2
Application number	US-201715696919-A
Country	US
Kind code	B2
Filing date	Sep 6, 2017
Priority date	Dec 27, 2012
Publication date	Jun 5, 2018
Grant date	Jun 5, 2018

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 vacuum box downstream of the electron gun and coupled with the electron gun;
a scanning device configured to generate a scanning magnetic field to deflect the electron beam currents;
a current-limiting device arranged in the vacuum box and having a plurality of regularly-arranged holes, wherein when the electron beam currents scan through the current-limiting device under the control of the scanning device, electron beams corresponding to positions of the holes in the scanning order are outputted from the current-limiting device; and
an anode target arranged in the vacuum box and downstream of the current-limiting device, wherein by applying a voltage, an electric field is formed between the current-limiting device and the anode target to accelerate the electron beams from the current-limiting device, and wherein the accelerated electron beams bombard the anode target to generate x-rays.

2. The apparatus of claim 1 , wherein the scanning device is configured to periodically deflect the electron beam currents so as to scan the current-limiting device.

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

4. The apparatus of claim 3 , further comprising a plug-pull high-voltage connection device at a 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.

5. The apparatus of claim 3 , 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.

6. The apparatus of claim 5 , wherein the shielding and collimation device is made of leaded material.

7. The apparatus of claim 2 , wherein the current-limiting device comprises a strip-shaped metal plate having a plurality of holes.

8. The apparatus of claim 7 , wherein the width of each hole is selected from a range of 0.3 mm to 3 mm, and the length of each hole is selected from a range of 2 mm to 10 mm.

9. The apparatus of claim 7 , wherein an interval between two adjacent holes is not less than 2R, R being the radius of the beam spot of the electron beam currents projected onto the current-limiting device.

10. 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.

11. The apparatus of claim 2 , further comprising a vacuum ion pump attached to the vacuum box, the vacuum ion pump configured to maintain high vacuum inside the vacuum box.

12. The apparatus of claim 1 , wherein the current-limiting device is applied with the same voltage as an anode of the electron gun.

13. The apparatus of claim 1 , wherein imaginary 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.

14. The apparatus of claim 1 , further comprising 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, electron beams corresponding to positions of the holes in the scanning order are outputted in an array from the current-limiting device.

15. 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.

16. 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.

17. A method of generating distributed x-rays, the method comprising:
controlling an electron gun to generate electron beam currents, wherein a vacuum box is downstream of the electron gun and coupled with the electron gun;
controlling a scanning device to generate a scanning magnetic field to deflect the electron beam currents, the electron beam currents scanning through a plurality of holes regularly arranged on a current-limiting device under the control of the scanning device to output electron beams corresponding to positions of the holes in the scanning order, wherein the current-limiting device is arranged in the vacuum box; and
generating an electric field between the current-limiting device and an anode target to accelerate the electron beams from the current-limiting device by applying a voltage to the anode target, the accelerated electron beams bombarding the anode target to generate x-rays, wherein the anode target is arranged in the vacuum box and is located downstream of the current-limiting device.

18. The method of claim 17 , wherein imaginary 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.

19. The method of claim 17 , comprising controlling scanning of 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, electron beams corresponding to positions of the holes in the scanning order are outputted in an array from the current-limiting device.

20. An apparatus to generate distributed x-rays, the apparatus comprising:
an electron gun configured to generate electron beam currents;
a vacuum box downstream of the electron gun and coupled with the electron gun;
a scanning device configured to generate a scanning magnetic field to deflect the electron beam currents;
a current-limiting device arranged in the vacuum box and having a plurality of holes, wherein when the electron beam currents scan with respect to the current-limiting device under the control of the scanning device, electron beams corresponding to positions of the holes in the scanning order are outputted from the current-limiting device;
an anode target arranged in the vacuum box and downstream of the current-limiting device; and
a power supply system configured to, by application of a voltage, cause formation of an electric field between the current-limiting device and the anode target to accelerate the electron beams from the current-limiting device toward the anode target, wherein the accelerated electron beams bombard the anode target to generate x-rays.

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

• H01J35/16

  Vessels; Containers; Shields associated therewith · CPC title

• H01J35/14 Primary

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

• H01J35/153 Primary

  Spot position control · CPC title