METHOD FOR DETERMINING A QUALITY FACTOR OF AN ACCELERATING CAVITY OF A PARTICLE ACCELERATOR

• US 20200137869A1
• Filed: 10/24/2019
• Published: 04/30/2020
• Est. Priority Date: 10/24/2018
• Status: Active Grant

• Current Assignee: Commissariat a L'Energie Atomique (AES Corporation), Centre National De La Recherche Scientifique, Universite De Caen Normandie
• Original Assignee: Commissariat a L'Energie Atomique (AES Corporation)
• Inventors: Vassal, Adrien, Bonnay, Patrick, Bonne, Francois, Ghribi, Adnan
• Granted Patent: US 11,606,857 B2
• Time in Patent Office: Days
• CPC Class Codes: H05H 2007/025 Radiofrequency systems
• CPC Class Codes: H05H 2007/225 coupled cavities arrangements
• CPC Class Codes: H05H 2007/227 power coupling, e.g. coupling loops
• CPC Class Codes: H05H 7/20 with superconductive walls
• CPC Class Codes: H05H 7/22 Details of linear accelerators, e.g. drift tubes H05H7/02 - H05H7/20 take precedence

Abstract

The method for determining a quality factor of an accelerating superconducting cavity of a particle accelerator, in particular a linear particle accelerator, the method includes

determining a heat load to which a cryomodule having the accelerating cavity and a bath of cryogenic fluid is subjected, then

determining a quality factor based on the determination of the heat load during the operation of the particle accelerator.

Claims

1. A method for determining a quality factor of an accelerating superconducting cavity of a particle accelerator, the method comprising:

determining a heat load to which a cryomodule having the accelerating cavity and a bath of cryogenic fluid is subjected; and

determining a quality factor based on the determination of the heat load during the operation of the particle accelerator.

2. The method according to claim 1, wherein the determining the heat load and determining the quality factor carried out simultaneously and in real time.

3. The method according to claim 1, wherein the determining the heat load comprises the use of a state observer.

4. The method according to claim 3, wherein the use of the state observer comprises an estimation of a mass flow rate ({dot over (m)}) of cryogenic fluid passing through a valve of the cryomodule taking a form

{dot over (m)}=β

_T·

{dot over (m)}_comp+(1−

β

_T)·

{dot over (m)}_incomp

in which;

{dot over (m)}_comp is a mass flow rate of cryogenic fluid in compressible form through a valve,

{dot over (m)}_incomp is the mass flow rate of cryogenic fluid in incompressible form through the valve, and

β

_T is a coefficient of isothermal compressibility of the cryogenic fluid.

5. The method according to claim 3, wherein the state observer comprises an estimation of a density and of a specific internal energy of a bath of cryogenic fluid.

6. The method according to claim 5, wherein the estimation is carried out based on:

a volume of the cryogenic fluid in a liquid state, which is calculated based on a measurement of a height of the cryogenic fluid in the liquid state; and

a static heat load and a dynamic heat load received by the bath of cryogenic fluid; and

an input specific enthalpy and an output specific enthalpy of the cryogenic bath, based on a measurement of a pressure of the bath of cryogenic fluid.

7. A method for operating a particle accelerator, having at least one accelerating cavity, the operating method comprising implementing the method for determining a quality factor of at least one accelerating cavity according to claim 1 and modifying at least one operating parameter of the accelerating cavity depending on a quality factor of the accelerating cavity.

8. An operating method according to claim 7, wherein the at least one operating parameter is a power setpoint value for a radiofrequency wave emitted in the accelerating cavity, and wherein the modifying comprising decreasing the value of the power setpoint if the quality factor of the at least one accelerating cavity crosses a preset threshold, the other cavities of the particle accelerator, when they exist, being able to continue to operate.

9. A device for determining a quality factor of at least one accelerating cavity of a particle accelerator, the determining device comprising hardware and/or software elements that implement the method according to claim 1.

10. A particle accelerator comprising at least one determining device according to claim 9.

11. The particle accelerator according to claim 10, comprising at least one cryomodule having an accelerating cavity and a bath of a cryogenic fluid.

12. A computer program product, comprising program-code instructions stored on a computer-readable medium, for implementing the method according to claim 1.

13. A non-transitory computer-recording medium having embodied thereon a program, which when executed by a computer causes the computer to execute a method according to claim 1.

14. The method according to claim 5, wherein the estimation is carried out based on:

a volume of the cryogenic fluid in a liquid state, which is calculated based on a measurement of an amount of the cryogenic fluid entering and exiting the bath of cryogenic fluid; and

a static heat load and a dynamic heat load received by the bath of cryogenic fluid; and

an input specific enthalpy and an output specific enthalpy of the cryogenic bath, based on a measurement of a pressure of the bath of cryogenic fluid.

15. The method according to claim 5, wherein the estimation is carried out based on:

a volume of the cryogenic fluid in a liquid state, which is calculated based on a measurement of a height of the cryogenic fluid in the liquid state; and

a static heat load and a dynamic heat load received by the bath of cryogenic fluid; and

an output temperature of the bath of cryogenic fluid, based on a measurement of the pressure of the bath of cryogenic fluid and on an input mass concentration of the bath of cryogenic fluid.

16. The method according to claim 5, wherein the estimation is carried out based on:

a volume of the cryogenic fluid in a liquid state, which is calculated based on a measurement of an amount of the cryogenic fluid entering and exiting the bath of cryogenic fluid; and

a static heat load and a dynamic heat load received by the bath of cryogenic fluid; and

an output temperature of the bath of cryogenic fluid, based on a measurement of the pressure of the bath of cryogenic fluid and on an input mass concentration of the bath of cryogenic fluid.

17. The method according to claim 5, wherein the estimation is carried out based on:

a volume of the cryogenic fluid in a liquid state, which is calculated based on a measurement of a height of the cryogenic fluid in the liquid state and a measurement of an amount of the cryogenic fluid entering and exiting the bath of cryogenic fluid; and

a static heat load and a dynamic heat load received by the bath of cryogenic fluid; and

an input specific enthalpy and an output specific enthalpy of the cryogenic bath, based on a measurement of a pressure of the bath of cryogenic fluid.

18. The method according to claim 5, wherein the estimation is carried out based on:

a volume of the cryogenic fluid in a liquid state, which is calculated based on a measurement of a height of the cryogenic fluid in the liquid state and on a measurement of an amount of the cryogenic fluid entering and exiting the bath of cryogenic fluid; and

a static heat load and a dynamic heat load received by the bath of cryogenic fluid; and

an output temperature of the bath of cryogenic fluid, based on a measurement of the pressure of the bath of cryogenic fluid and on an input mass concentration of the bath of cryogenic fluid.

19. The particle accelerator according to claim 10, comprising at least one cryomodule having a plurality of accelerating cavities and a bath of a cryogenic fluid.

20. The method according to claim 4, wherein the particle accelerator is a linear particle accelerator.