SRF2013 - List of Authors (Bousson, S.)

Paper

Title

Page

The ESS Superconducting Linear Accelerator

77

C. Darve, M. Eshraqi, M. Lindroos, D.P. McGinnis, S. Molloy
ESS, Lund, Sweden
P. Bosland
CEA/IRFU, Gif-sur-Yvette, France
S. Bousson
IPN, Orsay, France

The European Spallation Source (ESS) is one of Europe's largest planned research infrastructure. The collaborative project is funded by a collaboration of 17 European countries and is under design and construction in Lund, Sweden. The ESS will bring new insights to the grand challenges of science and innovation in fields as diverse as material and life sciences, energy, environmental technology, cultural heritage solid-state and fundamental physics. A 5 MW, long pulse proton accelerator is used to reach this goal. The pulsed length is 2.86 ms, the repetition frequency is 14 Hz (4 % duty cycle). The choice of SRF technology is a key element in the development of the ESS linear accelerator(linac). The superconducting linac is composed of one section of spoke cavity cryomodule (352 MHz) and two sections of elliptical cavity cryomodules (704 MHz). These cryomodules contain Niobium SRF cavities operating at 2 K. This paper presents the superconducting linac layout and its lifecycle.

MOP089

Design of the ESS Spoke Cryomodule

357

D. Reynet, S. Bousson, S. Brault, P. Duchesne, P. Duthil, N. Gandolfo, G. Olry, E. Rampnoux
IPN, Orsay, France

The European Spallation Source (ESS) project brings together 17 European countries to develop the world’s most powerful neutron source feeding multidisplinary researches. The superconducting part of the linear accelerator consists in 59 cryomodules housing different superconducting radiofrequency (SRF) resonators among which 28 paired β=0.5 352.2 MHz SRF niobium double Spoke cavities, held at 2K in a saturated helium bath. A prototype Spoke cryomodule with two cavities equipped with their 300kW RF power couplers is now being designed and will be constructed and tested at full power by the end of 2015 for the validation of all chosen technical solutions. It integrates all the interfaces necessary to be operational within a linac machine. Its assembly requires dedicated tooling and procedures in and out of a clean room. The design takes into account an industrial approach for the management of the fabrication costs. This prototype will have to guarantee an accelerating field of 8MV/m while optimizing the energy consumption and will aim at assessing the maintenance operations issues. We propose to present the design of this cryomodule and its related tooling.

THIOD04

A Cold Tuner System With Mobile Plunger

884

D. Longuevergne, S. Blivet, S. Bousson, N. Gandolfo, G. Martinet, G. Olry, H. Saugnac
IPN, Orsay, France

Tuner systems for accelerating cavities are required to compensate static and dynamic frequency perturbations during beam operation. In the case of superconducting cavities, these are commonly tuned by deforming the cavity wall in specific places of the geometry. Nevertheless, considering the mechanical properties and frequency versus displacement sensitivity of some structures, tuning by deformation doesn’t allow to meet the requirements. In these specific cases, inspired from the “room temperature technology”, an alternative tuning technique by insertion of a helium-cooled superconducting plunger can be considered and has been studied for several projects (IFMIF, ESS-BILBAO). Advantages and drawbacks of such solution will be discussed and the successful results on SPIRAL2 cryomodule developed at IPNO will be presented.

Slides THIOD04 [4.938 MB]

THP065

Design of 352.21 MHz RF Power Input Coupler and Window for the European Spallation Source Project (ESS)

1069

E. Rampnoux, S. Bousson, S. Brault, P. Duchesne, P. Duthil, G. Olry, D. Reynet
IPN, Orsay, France

A 352.21 MHz RF high power coupler window was designed by IPNO to meet the specification requirements for the ESS accelerator project. This designed is based on IPNO’s power coupler developments performed in the framework of the EURISOL Design Study project for which two power couplers using coaxial technology without chokes systems around the ceramic disc have been designed and tested successfully up to 20 kW RF power level in CW mode. For ESS project, the RF power input window was developed and designed to reliability operate at an average power level of 25 kW up to 300 kW in pulsed and continuous wave modes. This 352.21 MHz RF window was developed to remove the chocks usually used and provided the following advantages: more reliability, less expensive to manufacture, better vacuum, easier cleaning, less secondary electron-multipacting with specificity to present a bandwidth close to 1 GHz.

THP078

Deformation Tuner Design for a Double Spoke Cavity

1104

N. Gandolfo, S. Bousson, S. Brault, P. Duchesne, P. Duthil, G. Olry, D. Reynet
IPN, Orsay, France

IPN Orsay is developing the low-beta double Spoke cavities cryomodule for the ESS. Based on previous successfully tested prototypes, a fast/slow tuner has been studied to compensate resonance frequency variations of the cavity during operation. The typical perturbations are coming from LHe pressure variations as well as microphonics and Lorentz force detuning (LFD). Two tuners are being built in order to validate both expected performances and series production feasibility. In this paper, the tuner design of the double Spoke cavity is presented.

FRIOC01

Design of the 352 MHz, Beta 0.50, Double-Spoke Cavity for ESS

1212

P. Duchesne, S. Bousson, S. Brault, P. Duthil, G. Olry, D. Reynet
IPN, Orsay, France
S. Molloy
ESS, Lund, Sweden

The ESS proton accelerator contains a superconducting sector consisting in three families of superconducting radiofrequency (SRF) bulk niobium cavities, operating at a nominal temperature of 2K: a family of Spoke cavities for the medium energy section followed by two families of elliptical cavities for higher energies. The superconducting Spoke section, having a length of 58.6m, consists of 14 cryomodules, each of them housing two 352.2 MHz β=0.50 Double-Spoke Resonators (DSR). The operating accelerating field is 8MV/m. The choice of the Spoke technology is guided by the high performances of such structures. Benefitting from 10 years of extensive R&D experience carried out at IPNO, the electromagnetic design studies came out with a solution that fulfills requirements of beam dynamics analysis and manufacturing considerations. Pursuing the same objective, the mechanical design of the cavity and its helium vessel were optimized by performing intensive coupled RF-mechanical simulations. We propose to present a review of the RF and mechanical design studies of the Spoke cavity. We will conclude with the integration of the Spoke cavity with its ancillaries inside the cryomodule.

Slides FRIOC01 [6.321 MB]

Paper	Title	Page
MOP004	The ESS Superconducting Linear Accelerator	77
	C. Darve, M. Eshraqi, M. Lindroos, D.P. McGinnis, S. Molloy ESS, Lund, Sweden P. Bosland CEA/IRFU, Gif-sur-Yvette, France S. Bousson IPN, Orsay, France
	The European Spallation Source (ESS) is one of Europe's largest planned research infrastructure. The collaborative project is funded by a collaboration of 17 European countries and is under design and construction in Lund, Sweden. The ESS will bring new insights to the grand challenges of science and innovation in fields as diverse as material and life sciences, energy, environmental technology, cultural heritage solid-state and fundamental physics. A 5 MW, long pulse proton accelerator is used to reach this goal. The pulsed length is 2.86 ms, the repetition frequency is 14 Hz (4 % duty cycle). The choice of SRF technology is a key element in the development of the ESS linear accelerator(linac). The superconducting linac is composed of one section of spoke cavity cryomodule (352 MHz) and two sections of elliptical cavity cryomodules (704 MHz). These cryomodules contain Niobium SRF cavities operating at 2 K. This paper presents the superconducting linac layout and its lifecycle.

MOP089	Design of the ESS Spoke Cryomodule	357
	D. Reynet, S. Bousson, S. Brault, P. Duchesne, P. Duthil, N. Gandolfo, G. Olry, E. Rampnoux IPN, Orsay, France
	The European Spallation Source (ESS) project brings together 17 European countries to develop the world’s most powerful neutron source feeding multidisplinary researches. The superconducting part of the linear accelerator consists in 59 cryomodules housing different superconducting radiofrequency (SRF) resonators among which 28 paired β=0.5 352.2 MHz SRF niobium double Spoke cavities, held at 2K in a saturated helium bath. A prototype Spoke cryomodule with two cavities equipped with their 300kW RF power couplers is now being designed and will be constructed and tested at full power by the end of 2015 for the validation of all chosen technical solutions. It integrates all the interfaces necessary to be operational within a linac machine. Its assembly requires dedicated tooling and procedures in and out of a clean room. The design takes into account an industrial approach for the management of the fabrication costs. This prototype will have to guarantee an accelerating field of 8MV/m while optimizing the energy consumption and will aim at assessing the maintenance operations issues. We propose to present the design of this cryomodule and its related tooling.

THIOD04	A Cold Tuner System With Mobile Plunger	884
	D. Longuevergne, S. Blivet, S. Bousson, N. Gandolfo, G. Martinet, G. Olry, H. Saugnac IPN, Orsay, France
	Tuner systems for accelerating cavities are required to compensate static and dynamic frequency perturbations during beam operation. In the case of superconducting cavities, these are commonly tuned by deforming the cavity wall in specific places of the geometry. Nevertheless, considering the mechanical properties and frequency versus displacement sensitivity of some structures, tuning by deformation doesn’t allow to meet the requirements. In these specific cases, inspired from the “room temperature technology”, an alternative tuning technique by insertion of a helium-cooled superconducting plunger can be considered and has been studied for several projects (IFMIF, ESS-BILBAO). Advantages and drawbacks of such solution will be discussed and the successful results on SPIRAL2 cryomodule developed at IPNO will be presented.
	Slides THIOD04 [4.938 MB]

THP065	Design of 352.21 MHz RF Power Input Coupler and Window for the European Spallation Source Project (ESS)	1069
	E. Rampnoux, S. Bousson, S. Brault, P. Duchesne, P. Duthil, G. Olry, D. Reynet IPN, Orsay, France
	A 352.21 MHz RF high power coupler window was designed by IPNO to meet the specification requirements for the ESS accelerator project. This designed is based on IPNO’s power coupler developments performed in the framework of the EURISOL Design Study project for which two power couplers using coaxial technology without chokes systems around the ceramic disc have been designed and tested successfully up to 20 kW RF power level in CW mode. For ESS project, the RF power input window was developed and designed to reliability operate at an average power level of 25 kW up to 300 kW in pulsed and continuous wave modes. This 352.21 MHz RF window was developed to remove the chocks usually used and provided the following advantages: more reliability, less expensive to manufacture, better vacuum, easier cleaning, less secondary electron-multipacting with specificity to present a bandwidth close to 1 GHz.

THP078	Deformation Tuner Design for a Double Spoke Cavity	1104
	N. Gandolfo, S. Bousson, S. Brault, P. Duchesne, P. Duthil, G. Olry, D. Reynet IPN, Orsay, France
	IPN Orsay is developing the low-beta double Spoke cavities cryomodule for the ESS. Based on previous successfully tested prototypes, a fast/slow tuner has been studied to compensate resonance frequency variations of the cavity during operation. The typical perturbations are coming from LHe pressure variations as well as microphonics and Lorentz force detuning (LFD). Two tuners are being built in order to validate both expected performances and series production feasibility. In this paper, the tuner design of the double Spoke cavity is presented.

FRIOC01	Design of the 352 MHz, Beta 0.50, Double-Spoke Cavity for ESS	1212
	P. Duchesne, S. Bousson, S. Brault, P. Duthil, G. Olry, D. Reynet IPN, Orsay, France S. Molloy ESS, Lund, Sweden
	The ESS proton accelerator contains a superconducting sector consisting in three families of superconducting radiofrequency (SRF) bulk niobium cavities, operating at a nominal temperature of 2K: a family of Spoke cavities for the medium energy section followed by two families of elliptical cavities for higher energies. The superconducting Spoke section, having a length of 58.6m, consists of 14 cryomodules, each of them housing two 352.2 MHz β=0.50 Double-Spoke Resonators (DSR). The operating accelerating field is 8MV/m. The choice of the Spoke technology is guided by the high performances of such structures. Benefitting from 10 years of extensive R&D experience carried out at IPNO, the electromagnetic design studies came out with a solution that fulfills requirements of beam dynamics analysis and manufacturing considerations. Pursuing the same objective, the mechanical design of the cavity and its helium vessel were optimized by performing intensive coupled RF-mechanical simulations. We propose to present a review of the RF and mechanical design studies of the Spoke cavity. We will conclude with the integration of the Spoke cavity with its ancillaries inside the cryomodule.
	Slides FRIOC01 [6.321 MB]