Slot-coupled CW standing wave accelerating cavity

• US 9,655,227 B2
• Filed: 06/05/2015
• Issued: 05/16/2017
• Est. Priority Date: 06/13/2014
• Status: Active Grant

• Current Assignee: Jefferson Science Associates, Llc
• Original Assignee: Jefferson Science Associates, Llc
• Inventors: Wang, Shaoheng, Rimmer, Robert, Wang, Haipeng
• Primary Examiner(s): Owens, Douglas W
• Assistant Examiner(s): Sathiraju, Srinivas
• Application Number:
  US14/731,887
• Publication Number:
  US 20150366046A1
• Time in Patent Office: 711 Days
• Field of Search: None
• CPC Class Codes: H05H 2007/225 coupled cavities arrangements
• CPC Class Codes: H05H 7/18 Cavities; Resonators travelling-wave tubes H01J23/18; hyperfrequency cavities in general H01P7/04, H01P7/06
• CPC Class Codes: H05H 7/22 Details of linear accelerators, e.g. drift tubes H05H7/02 - H05H7/20 take precedence
• CPC Class Codes: H05H 9/044 Coupling cavity LINACS, e.g. side coupled

Abstract

A slot-coupled CW standing wave multi-cell accelerating cavity. To achieve high efficiency graded beta acceleration, each cell in the multi-cell cavity may include different cell lengths. Alternatively, to achieve high efficiency with acceleration for particles with beta equal to 1, each cell in the multi-cell cavity may include the same cell design. Coupling between the cells is achieved with a plurality of axially aligned kidney-shaped slots on the wall between cells. The slot-coupling method makes the design very compact. The shape of the cell, including the slots and the cone, are optimized to maximize the power efficiency and minimize the peak power density on the surface. The slots are non-resonant, thereby enabling shorter slots and less power loss.

Claims

1. A slot-coupled continuous wave (CW) graded beta standing wave accelerating cavity, comprising:

a plurality of interconnected cells including a gap spacing, a cell length, a cone having a cone angle, a center bore, and a center axis extending longitudinally through the center bore;

a wall between each of said interconnected cells;

a plurality of non resonant coupling slots on the walls between said interconnected cells;

said coupling slots in said walls are in axial alignment with a corresponding slot in the plurality of interconnected cells and are offset to a common side from the center axis of the accelerating cavity;

the plurality of interconnected cells including a gap spacing and cell length that are varied throughout the length of the interconnected cells to accommodate varying beta and the cone angle is constant throughout the length of the interconnected cells;

the interconnected cells include a center symmetric axis and the slots in each wall are axisymmetric about the center axis; and

each of said coupling slots extends no more than an angle of 60 degrees around the center symmetric axis.

2. The slot-coupled CW standing wave accelerating cavity of claim 1, further comprising

an equator on each of said cells;

and

a cylindrical strip at each equator.

3. The slot-coupled CW standing wave accelerating cavity of claim 1, wherein said slots are kidney-shaped.

4. The slot-coupled CW standing wave accelerating cavity of claim 1, further comprising three or more of said slots on each of said walls.

5. The slot-coupled CW standing wave accelerating cavity of claim 2, wherein each of said cells in said plurality of interconnected cells is of a different length for graded beta acceleration.

6. The slot-coupled CW standing wave accelerating cavity of claim 5, wherein the width of the cylindrical strip is changed for different cells to vary the cell length.

7. The slot-coupled CW standing wave accelerating cavity of claim 1, wherein

the plurality of cells include a gap spacing and a cell length;

the plurality of cells form a graded beta cavity; and

the gap spacing and cell length are varied to accommodate varying beta and form a graded beta cavity.

8. The slot-coupled CW standing wave accelerating cavity of claim 7, wherein

each of the interconnected cells in the plurality of cells include a cone angle;

and

the cone angle is same for all cells.

9. The slot-coupled CW standing wave accelerating cavity of claim 1, wherein each of said cells in said plurality of interconnected cells is of equal lengths for beta equal to 1 acceleration.

10. The slot-coupled CW standing wave accelerating cavity of claim 1, further comprising an internal cooling channel in each wall.

11. The slot-coupled CW standing wave accelerating cavity of claim 1, wherein the dimensions and geometry for the cell walls and slots are the same in each cell.

12. A method for high efficiency continuous wave (CW) graded beta acceleration, comprising:

a. providing a particle accelerator including a plurality of interconnected cells of varying length separated by walls there between, the interconnected cells including a center symmetric axis, a gap spacing, a cell length, and a cone having a cone angle;

b. providing a plurality of non resonant coupling slots on the walls between the interconnected cells to enable a pi-mode oscillating field;

c. axially aligning the coupling slots in the walls along an axis parallel with and offset to a common side from the center symmetric axis;

d. varying the gap spacing and cell length throughout the length of the interconnected cells to accommodate varying beta;

e. maintaining a constant cone angle throughout the interconnected cells; and

f. limiting the extent of each of said coupling slots to no more than an angle of 60 degrees around the center symmetric axis.

13. The method of claim 12, further comprising

providing a gap spacing between the interconnected cells;

and

varying the gap spacing between the cells accommodate varying beta and form a graded beta cavity.

14. The method of claim 12, further comprising providing an internal cooling channel in each wall.

15. The method of claim 12, further comprising

providing a cone having a cone angle on each of said cells;

and

setting the cone angle the same for all cells.