Electromagnetic interference containment for accelerator systems

• US 10,366,859 B2
• Filed: 08/24/2016
• Issued: 07/30/2019
• Est. Priority Date: 08/24/2016
• Status: Active Grant

• Current Assignee: Varian Medical Systems Incorporated (Siemens AG)
• Original Assignee: Varian Medical Systems Incorporated (Siemens AG)
• Inventors: Trail, Mark E., Potter, Rudolf H.
• Primary Examiner(s): Owens, Douglas W
• Assistant Examiner(s): Sathiraju, Srinivas
• Application Number:
  US15/245,551
• Publication Number:
  US 20180061609A1
• Time in Patent Office: 1,070 Days
• Field of Search: None
• CPC Class Codes: H01J 23/14 Leading-in arrangements; Seals therefor
• CPC Class Codes: H01J 23/15 Means for preventing wave energy leakage structurally associated with tube leading-in arrangements, e.g. filters, chokes, attenuating devices
• CPC Class Codes: H01J 29/003 Arrangements for eliminating unwanted electromagnetic effects, e.g. demagnetisation arrangements, shielding coils H01J29/06, H01J29/867 take precedence; demagnetisation in general H01F13/00; circuit arrangements therefor H04N9/29; screening of apparatus against electric or magnetic fields H05K9/00
• CPC Class Codes: H01J 29/485 Construction of the gun or of parts thereof H01J29/481, H01J29/482, H01J29/484 and H01J29/487 take precedence
• CPC Class Codes: H01J 29/96 One or more circuit elements structurally associated with the tube

Abstract

An apparatus for attachment to a component of a microwave device, includes: a cage; a shield within the cage, wherein the shield is in a form of a container, at least a majority of the shield spaced away from an interior wall of the cage; and a connector at the cage, wherein the connector is configured to connect to a cable connection, and wherein the connector is electrically connected to two terminals within the shield. An apparatus for coupling to an input connection of an electron gun, the input connection having a heater terminal and a cathode terminal, the apparatus comprising: a connector having a first configured to attach to a cable, and a second end configured to connect to the input connection of the electron gun; and wherein the connector comprises an opening configured to receive the heater terminal of the input connection of the electron gun.

Claims

1. An apparatus for attachment to a component of a microwave device, comprising:

a cage;

a shield within the cage, wherein the shield is in a form of a container, and at least a majority of the shield is spaced away from an interior wall of the cage; and

a connector at the cage, wherein the connector is configured to connect to a cable connection, and wherein the connector is electrically connected to two terminals within the shield;

wherein a voltage between the two terminals has a first voltage value, and a voltage between the shield and the cage has a second voltage value that is higher than the first voltage.

2. The apparatus of claim 1, wherein the shield comprises a first opening for receiving wires from the connector.

3. The apparatus of claim 2, wherein the shield further comprises a second opening and a third opening for receiving the two terminals respectively.

4. The apparatus of claim 3, wherein one of the two terminals comprises a cathode terminal.

5. The apparatus of claim 4, wherein another one of the two terminals comprises a heater terminal.

6. The apparatus of claim 5, wherein the heater terminal is electrically isolated from the shield.

7. The apparatus of claim 4, wherein the cathode terminal is electrically connected to the shield.

8. The apparatus of claim 1, wherein the connector comprises a ground connection to the cage.

9. The apparatus of claim 1, wherein the second voltage is at least 1000 times larger than the first voltage.

10. The apparatus of claim 1, further comprising a RF absorber contained inside the cage.

11. The apparatus of claim 10, wherein the shield is coupled to the RF absorber.

12. The apparatus of claim 1, further comprising a protection circuit contained inside the shield.

13. The apparatus of claim 12, wherein the protection circuit comprises a capacitor and a voltage limiting device, the capacitor having a first lead and a second lead, the voltage limiting device having a third lead and a fourth lead, wherein the first lead of the capacitor and the third lead of the voltage limiting device are connected to one of the two terminals in the shield, and wherein the second lead of the capacitor and the fourth lead of the voltage limiting device are connected to another one of the two terminals in the shield.

14. The apparatus of claim 12, wherein the protection circuit is configured to prevent current from flowing through the protection circuit until a pre-determined voltage is reached.

15. The apparatus of claim 12, wherein the protection circuit comprises a bipolar or unipolar transient-voltage suppression (TSV) diode.

16. The apparatus of claim 1, wherein a portion of the shield comprises a dome shape.

17. The apparatus of claim 1, wherein the microwave device comprises a Magnetron, and wherein the cage is configured to attach to the component of the Magnetron.

18. An apparatus for attachment to a component of a microwave device, comprising:

a cage configured to provide EMI shielding; and

a shield within the cage, wherein the shield is configured to provide corona shielding;

wherein the shield comprises a cavity for accommodating two terminals; and

wherein a voltage between the two terminals has a first voltage value, and a voltage between the shield and the cage has a second voltage value that is higher than the first voltage.

19. The apparatus of claim 18, further comprising a protection circuit contained inside the shield.

20. The apparatus of claim 19, wherein the protection circuit comprises a capacitor and a voltage limiting device, the capacitor having a first lead and a second lead, the voltage limiting device having a third lead and a fourth lead, wherein the first lead of the capacitor and the third lead of the voltage limiting device are connected to one of the two terminals in the shield, and wherein the second lead of the capacitor and the fourth lead of the voltage limiting device are connected to another one of the two terminals in the shield.

21. The apparatus of claim 19, wherein the protection circuit is configured to prevent current from flowing through the protection circuit until a pre-determined voltage is reached.

22. The apparatus of claim 19, wherein the protection circuit comprises a bipolar or unipolar transient-voltage suppression (TSV) diode.

23. The apparatus of claim 18, wherein one of the two terminals comprises a cathode terminal electrically connected to the shield.

24. The apparatus of claim 23, wherein another one of the two terminals comprises a heater terminal, the heater terminal being electrically isolated from the shield.