Systems, devices, and methods for initiating beam transport in a beam system

Patent metadata

Field	Value
Publication number	US-12010788-B2
Application number	US-202117400979-A
Country	US
Kind code	B2
Filing date	Aug 12, 2021
Priority date	Aug 13, 2020
Publication date	Jun 11, 2024
Grant date	Jun 11, 2024

Abstract

Embodiments of systems, devices, and methods relate to initiating beam transport for an accelerator system. An example method includes increasing a bias voltage of one or more electrodes of the accelerator system to a first voltage level and extracting a charged particle beam from a beam source such that the beam is transported through the accelerator system. The beam has a beam current that results in a first transient voltage drop within a threshold. The method further includes increasing the beam current at a rate that results in one or more subsequent transient voltage drops within the threshold until the accelerator system has reached nominal conditions. Another example method includes biasing one or more electrodes of an accelerator system and selectively extracting, according to a duty cycle function, a charged particle beam from a beam source such that the charged particle beam is transported through the accelerator system.

First claim

What is claimed is:

1. A method of initiating beam transport for a tandem accelerator system, the method comprising:
biasing one or more electrodes of the tandem accelerator system to a first voltage level;
extracting a charged particle beam from a beam source such that the charged particle beam is transported through the tandem accelerator system, wherein the charged particle beam has a beam current at a first beam current level that results in a first transient voltage drop of the tandem accelerator system within a threshold such that the one or more electrodes maintain a non-zero voltage; and
increasing the beam current at a rate that results in one or more subsequent transient voltage drops of the tandem accelerator system until the beam current reaches a second beam current level, wherein the one or more subsequent transient voltage drops are within the threshold.

2. The method of claim 1 , wherein the threshold corresponds to a beam deflection time of the charged particle beam off of a beam axis that is less than a maximum beam deflection time.

3. The method of claim 1 , wherein the threshold corresponds to an adjustment response time of beam optics of a beam system within which the tandem accelerator system is situated.

4. The method of claim 1 , further comprising tuning the beam source to provide the charged particle beam having the beam current at the first beam current level.

5. The method of claim 4 , wherein the beam source is tuned prior to extracting the charged particle beam.

6. The method of claim 4 , wherein extracting the charged particle beam comprises biasing an extraction electrode upon determining that the beam source is tuned.

7. The method of claim 4 , wherein tuning the beam source comprises sending a command to the beam source to operate at the first beam current level.

8. The method of claim 7 , wherein tuning the beam source is performed prior to biasing one or more electrodes of the tandem accelerator system to a first voltage level.

9. The method of claim 1 , wherein increasing the beam current comprises sending a command to the beam source to operate at the second beam current level.

10. The method of claim 4 , wherein the beam source is an ion source, and tuning the ion source comprises matching a plasma parameter near an ion extraction region of the source such that the plasma is sufficient for extraction of the ion beam at the requested current.

11. The method of claim 10 , wherein the ion source comprises a volumetric type ion source and tuning the ion source comprises controlling one or more of controlling arc discharge current, filament current, plasma electrode voltage, extraction electrode voltage, or a rate of hydrogen gas feeding into the ion source.

12. The method of claim 1 , wherein extracting the charged particle beam is performed after one or more electrodes of the tandem accelerator system have reached the first voltage level.

13. The method of claim 1 , wherein the beam source is configured to provide a charged particle beam to the tandem accelerator system, the tandem accelerator system positioned downstream of the beam source.

14. The method of claim 1 , wherein the beam source is configured to generate a negative hydrogen ion beam.

15. The method of claim 1 , wherein the beam source comprises a non-cesiated ion source.

16. The method of claim 1 , wherein the tandem accelerator system comprises a first plurality of electrodes, a charge exchange device, and a second plurality of electrodes.

17. The method of claim 16 , wherein biasing one or more electrodes of the tandem accelerator system to the first voltage level comprises biasing the first plurality of electrodes and the second plurality of electrodes.

18. The method of claim 16 , wherein the charged particle beam is a negative ion beam, and wherein the first plurality of electrodes is configured to accelerate the negative ion beam from a pre-accelerator system, the charge exchange device is configured to convert the negative ion beam to a positive beam, and the second plurality of electrodes is configured to accelerate the positive beam.

19. The method of claim 18 , further comprising forming a neutral beam from the positive beam with a target device.

20. The method of claim 1 , further comprising:
accelerating the charged particle beam, using a pre-accelerator system, as it is propagated from the beam source, through the pre-accelerator system, and to the tandem accelerator system.

21. The method of claim 1 , further comprising:
reducing a bias on one or more electrodes of the tandem accelerator system as a result of a breakdown event at the tandem accelerator system prior to biasing the one or more electrodes of the tandem accelerator system to the first voltage level.

22. The method of claim 21 , further comprising:
determining to restart the tandem accelerator system prior to biasing the one or more electrodes of the tandem accelerator system to the first voltage level.

23. The method of claim 1 , wherein the first beam current level is in a range of 0.01 to 75% of a steady state charge current for the tandem accelerator system.

24. The method of claim 1 , wherein the second beam current level is a nominal treatment level.

25. The method of claim 1 , wherein the charged particle beam is a negative ion beam.

26. A beam system, comprising:
a beam source;
a tandem accelerator system comprising one or more electrodes configured to be biased to a first voltage level; and
a control system configured to:
control the beam source to produce a charged particle beam having a beam current at a first beam current level corresponding to a first transient voltage drop of the tandem accelerator system within a threshold such that the one or more electrodes maintain a non-zero voltage; and
control the beam source to increase the beam current at a rate that results in one or more subsequent transient voltage drops of the tandem accelerator system until the beam current reaches a second beam current level, wherein the one or more subsequent transient voltage drops are within the threshold.

Assignees

• Tae Tech Inc

Inventors

• Vekselman Vladislav
• Duong Suu
• Dunaevsky Alexander
• Sorokin Igor Nikolaevich

Classifications

• H05H2007/227

  power coupling, e.g. coupling loops · CPC title

• H05H2007/225

  coupled cavities arrangements · CPC title

• H05H2277/11

  Radiotherapy · CPC title

• H05H9/02 Primary

  Travelling-wave linear accelerators {(travelling-wave tubes H01J25/34)} · CPC title

• H05H5/063 Primary

  Tandems · CPC title