Grid voltage generation for x-ray tube

• US 9,351,387 B2
• Filed: 05/22/2015
• Issued: 05/24/2016
• Est. Priority Date: 12/21/2012
• Status: Expired due to Fees

• Current Assignee: Moxtek Inc (Nippon Kayaku Company Limited)
• Original Assignee: Moxtek Inc (Nippon Kayaku Company Limited)
• Inventors: Wang, Dongbing
• Primary Examiner(s): LOGIE, MICHAEL J
• Application Number:
  US14/720,338
• Publication Number:
  US 20150257244A1
• Time in Patent Office: 368 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: H05G 1/00 X-ray apparatus involving X-ray tubes; Circuits therefor
• CPC Class Codes: H05G 1/06 X-ray tube and at least part of the power supply apparatus being mounted within the same housing
• CPC Class Codes: H05G 1/08 Electrical details
• CPC Class Codes: H05G 1/085 Circuit arrangements particularly adapted for X-ray tubes having a control grid
• CPC Class Codes: H05G 1/10 Power supply arrangements for feeding the X-ray tube supply circuits with converters in general H02M; supply circuits for emitters and amplifiers H04B1/16 - H04B1/1623
• CPC Class Codes: H05G 1/12 with dc or rectified single-phase ac or double-phase

Abstract

An x-ray source for improved electron beam control, a smaller electron beam spot size, and a smaller x-ray spot size with reduced power supply size and weight. A method for improved electron beam control, a smaller electron beam spot size, and a smaller x-ray spot size with reduced power supply size and weight. Grid(s) may be used in an x-ray tube for improved electron beam control, a smaller electron beam spot size, and a smaller x-ray spot size. Control circuitry for the grid(s) can be disposed in electrically insulative potting. Light may be used to provide power and control signals to the control circuitry.

Claims

1. An x-ray source comprising:

a. an x-ray tube including;

i. an anode attached to an evacuated enclosure, the anode configured to emit x-rays;

ii. a cathode including an electron emitter attached to the evacuated enclosure, the electron emitter configured to emit electrons towards the anode;

iii. an electrically conducting grid disposed between the electron emitter and the anode, with a gap between the grid and the anode, and a gap between the grid and the electron emitter;

b. an internal grid control configured to provide alternating current;

c. a grid high voltage multiplier electrically coupled between the internal grid control and the grid;

d. the grid high voltage multiplier configured to receive alternating current from the internal grid control, generate a direct current (“

DC”

) voltage based on the alternating current, and provide the DC voltage to the grid;

e. a primary high voltage multiplier configured to provide a DC bias voltage at a high voltage connection to the electron emitter, the grid high voltage multiplier, and the internal grid control;

f. electrically insulating potting substantially surrounding a cathode end of an exterior of the x-ray tube, at least part of the primary high voltage multiplier including a high voltage connection end, the grid high voltage multiplier, and the internal grid control; and

g. a solar cell electrically coupled to the internal grid control and disposed in the potting, and wherein the solar cell is configured to receive light emitted by an external light source and configured to convert energy from the light into electrical energy for the internal grid control.

2. The x-ray source of claim 1, further comprising a battery electrically coupled to the internal grid control and to the solar cell and disposed in the potting, the solar cell is configured to provide electrical power to the battery to recharge the battery, and the battery is configured to provide electrical power to the internal grid control.

3. The x-ray source of claim 1, wherein the potting is substantially transparent to light, and the light from the external light source is emitted through the potting to the solar cell.

4. The x-ray source of claim 1, further comprising a power fiber optic cable extending through the potting and coupling the solar cell to the external light source, and the light is emitted from the external light source through the power fiber optic cable to the solar cell.

5. The x-ray source of claim 1, wherein:

a. the internal grid control is configured to receive a light control signal emitted by an external grid control;

b. the internal grid control is configured to modify the alternating current to the grid high voltage multiplier based on the light control signal; and

c. the grid high voltage multiplier is configured to modify a grid voltage based on the modified alternating current.

6. The x-ray source of claim 5, wherein the internal grid control further comprises a light control sensor that is configured to receive the light control signal.

7. The x-ray source of claim 5, further comprising the external grid control.

8. The x-ray source of claim 5, further comprising a transformer disposed in the potting and wherein:

a. the transformer is electrically coupled between the internal grid control and the grid high voltage multiplier; and

b. the transformer is configured to transfer electrical power from the internal grid control to the grid high voltage multiplier.

9. The x-ray source of claim 5, wherein the potting is substantially transparent to light, and the light control signal is emitted from the external grid control through the potting to the internal grid control.

10. The x-ray source of claim 5, further comprising a control fiber optic cable extending through the potting and coupling the light sensor of the internal grid control to the external grid control, and the light control signal is emitted from the external grid control through the control fiber optic cable to the light sensor.

11. The x-ray source of claim 1, wherein:

a. the grid is a first grid, and further comprising a second electrically conducting grid disposed between the first grid and the anode, with a gap between the second grid and the anode, and a gap between the first grid and the second grid;

b. the internal grid control is a first internal grid control, and further comprising a second internal grid control configured to provide alternating current;

c. the DC voltage is a first DC voltage;

d. the grid high voltage multiplier is a first grid high voltage multiplier, and further comprising a second grid high voltage multiplier electrically coupled between the second internal grid control and the second grid;

e. the second grid high voltage multiplier configured to receive alternating current from the second internal grid control, generate a second DC voltage based on the alternating current from the second internal grid control, and provide the second DC voltage to the second grid;

f. one of the first grid high voltage multiplier or the second grid high voltage multiplier is configured to provide a DC voltage to the first grid or to the second grid that is more positive than the DC bias voltage provided by the primary high voltage multiplier, and the other of the first grid high voltage multiplier or the second grid high voltage multiplier is configured to provide a DC voltage to the other of the first grid or second grid that is less positive than the DC bias voltage provided by the primary high voltage multiplier;

g. the high voltage connection of the primary high voltage multiplier electrically coupled to the second grid high voltage multiplier and to the second internal grid control; and

h. electrically insulating potting substantially surrounding the second grid high voltage multiplier and the second internal grid control.

12. The x-ray source of claim 11, wherein:

a. the first internal grid control is configured to receive a first light control signal emitted by a first external grid control;

b. the first internal grid control is configured to modify the alternating current to the first grid high voltage multiplier based on the first light control signal;

c. the first grid high voltage multiplier is configured to modify a voltage of the first grid based on the modified alternating current;

d. the second internal grid control is configured to receive a second light control signal emitted by the second external grid control;

e. the second internal grid control is configured to modify the alternating current to the second grid high voltage multiplier based on the second light control signal; and

f. the second grid high voltage multiplier is configured to modify the second grid voltage based on the modified alternating current.

13. An x-ray source comprising:

a. an x-ray tube including;

i. an anode attached to an evacuated enclosure, the anode configured to emit x-rays;

ii. a cathode including an electron emitter attached to the evacuated enclosure, the electron emitter configured to emit electrons towards the anode;

iii. an electrically conducting grid disposed between the electron emitter and the anode, with a gap between the grid and the anode, and a gap between the grid and the electron emitter;

b. an internal grid control configured to provide alternating current;

c. a grid high voltage multiplier electrically coupled between the internal grid control and the grid;

d. the grid high voltage multiplier configured to receive alternating current from the internal grid control, generate a direct current (“

DC”

) voltage based on the alternating current, and provide the DC voltage to the grid;

e. a primary high voltage multiplier configured to provide a DC bias voltage at a high voltage connection to the electron emitter, the grid high voltage multiplier, and the internal grid control;

f. electrically insulating potting substantially surrounding a cathode end of an exterior of the x-ray tube, at least part of the primary high voltage multiplier including a high voltage connection end, the grid high voltage multiplier, and the internal grid control; and

g. a solar cell and a battery disposed in the potting and electrically coupled to each other and to the internal grid control;

h. the solar cell configured to receive light emitted by an external light source and configured to convert energy from the light into electrical energy to charge the battery with electrical power; and

i. the battery configured to provide electrical power to the internal grid control.

14. The x-ray source of claim 13, wherein the potting is substantially transparent to light, and the light from the external light source is emitted through the potting to the solar cell.

15. The x-ray source of claim 13, further comprising a power fiber optic cable extending through the potting and coupling the solar cell to the external light source, and the light is emitted from the external light source through the power fiber optic cable to the solar cell.

16. The x-ray source of claim 13, wherein:

a. the internal grid control is configured to receive a light control signal emitted by an external grid control;

b. the internal grid control is configured to modify the alternating current to the grid high voltage multiplier based on the light control signal; and

c. the grid high voltage multiplier is configured to modify a grid voltage based on the modified alternating current.

17. The x-ray source of claim 16, wherein the internal grid control further comprises a light control sensor that is configured to receive the light control signal.

18. The x-ray source of claim 16, further comprising the external grid control.

19. The x-ray source of claim 16, further comprising a transformer disposed in the potting and wherein:

a. the transformer is electrically coupled between the internal grid control and the grid high voltage multiplier; and

b. the transformer is configured to transfer electrical power from the internal grid control to the grid high voltage multiplier.

20. The x-ray source of claim 16, wherein the potting is substantially transparent to light, and the light control signal is emitted from the external grid control through the potting to the internal grid control.