Compact linear accelerator with accelerating waveguide
A linear accelerator head for use in a medical radiation therapy system can include a housing, an electron generator configured to emit electrons along a beam path, and a microwave generation assembly. The linear accelerator head may include a waveguide that is configured to contain a standing or travelling microwave. The waveguide can include a plurality of cells that are disposed adjacent one another, wherein each of the plurality of cells may define an aperture configured to receive electrons therethrough. The linear accelerator head can further include a converter and a primary collimator.
1. A method of manufacturing a linear accelerator head, the method comprising:
assembling a waveguide comprising a plurality of cells, wherein each of the plurality of cells defines an aperture configured to receive electrons therethrough, the aperture of the plurality of cells having a diameter and defining a beam axis along a beam path, wherein assembling the plurality of cells comprises:
for each of a first plurality of cells, providing a first brazing alloy between two adjacent cell members; and
heating each of the first plurality of cells to a first brazing temperature;
providing an electron generator configured to emit electrons along the beam path;
providing a microwave generation assembly comprising:
a microwave generator configured to emit microwaves in a first direction along a primary wave path; and
an isolator configured to prevent microwaves from propagating in a second direction opposite the first direction along the primary wave path;
providing a cooling system in thermal communication with the waveguide;
providing a converter disposed within the electron beam path and configured to receive incident electrons, wherein the converter is configured to convert incident electrons into photons; and
providing a first collimator configured to define a beam shape, wherein the first collimator comprises an input aperture and an output aperture.
2. The method of manufacturing a linear accelerator head of claim 1 , wherein assembling the plurality of cells comprises, for each of the first plurality of cells, machining a cavity into a portion of each of the two adjacent cell members.
3. The method of manufacturing a linear accelerator head of claim 1 , wherein the first brazing alloy comprises between about 50% and about 90% copper by weight.
4. The method of manufacturing a linear accelerator head of claim 1 , wherein the first brazing alloy comprises between about 10% and about 50% gold by weight.
5. The method of manufacturing a linear accelerator head of claim 1 , wherein the first brazing temperature is between about 900° C. and about 1100° C.
6. The method of manufacturing a linear accelerator head of claim 1 , wherein assembling the plurality of cells comprises:
for each of a second plurality of cells, providing a second brazing alloy between two adjacent cell members; and
heating each of a second plurality of cells to a second brazing temperature.
7. The method of manufacturing a linear accelerator head of 6 , wherein assembling the plurality of cells comprises, for each of the first plurality of cells, machining a cavity into a portion of each of the two adjacent cell members.
8. The method of manufacturing a linear accelerator head of claim 6 , wherein the second brazing alloy comprises between about 35% and about 75% copper by weight.
9. The method of manufacturing a linear accelerator head of claim 6 , wherein the second brazing alloy comprises between about 25% and about 65% gold by weight.
10. The method of manufacturing a linear accelerator head of claim 6 , wherein the second brazing alloy comprises a lower percentage by weight of copper than the first brazing alloy.
11. The method of manufacturing a linear accelerator head of claim 1 , wherein providing the cooling system in thermal communication with the waveguide comprises:
providing a third brazing alloy between the waveguide and a cooling plate, the cooling plate comprising a channel configured to guide fluid therethrough; and
heating the waveguide and cooling plate to a third brazing temperature.
12. The method of manufacturing a linear accelerator head of claim 11 , wherein the third brazing temperature is between about 700° C. and about 1000° C.
13. The method of manufacturing a linear accelerator head of claim 11 , wherein the third brazing alloy comprises between about 10% and about 50% copper by weight.
14. The method of manufacturing a linear accelerator head of claim 11 , wherein the third brazing alloy comprises between about 50% and about 10% gold by weight.
15. The method of manufacturing a linear accelerator head of claim 11 , wherein the third brazing alloy comprises a lower percentage by weight of copper than the first brazing alloy.
16. The method of manufacturing a linear accelerator head of claim 1 , further comprising dipping the first plurality of cells into a solvent configured to dissolve oil.
17. The method of manufacturing a linear accelerator head of claim 1 , further comprising propagating sound waves at ultrasound frequency at the first plurality of cells.
18. The method of manufacturing a linear accelerator head of claim 1 , further comprising dipping the first plurality of cells into an etching solution configured to remove at least a layer of copper.
19. The method of manufacturing a linear accelerator head of claim 18 , wherein dipping the first plurality of cells into the etching solution comprises dipping the first plurality of cells into the etching solution for a total time of at least fifteen seconds.
20. The method of manufacturing a linear accelerator head of claim 18 , wherein the etching solution comprises phosphoric acid.