IPAC2018 - List of Keywords (recirculation)

Paper	Title	Other Keywords	Page
THPAK129	Modeling Challenges for Energy Recovery Linacs With Long, High Charge Bunches	bunching, space-charge, electron, lattice	3544
	C. Tennant JLab, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Historically, nearly all energy recovery linacs (ERLs) built and operated were used to drive a free-electron laser (FEL). The requirement for high peak current bunches necessitates bunch compression and handling the attendant beam dynamical challenges. In recent years, ERLs have turned from being drivers of light sources toward applications for nuclear physics experiments, Compton backscattering sources and strong electron cooling. Unlike an FEL, these latter uses require long, high charge bunches with small energy spread. The electron bunch must maintain a small projected energy spread and therefore must avoid gross distortion due to CSR and longitudinal space charge over a single (or multiple) recirculations. Accurately modeling the relevant collective effects in the system 'space charge, microbunching instability, CSR and the effect of shielding' in addition to beam dynamical processes such as halo, presents a formidable challenge. Absent a code that models all of these effects, we outline an approach towards the design, analysis and optimization of the high-energy electron cooler for the Jefferson Lab Electron-Ion Collider and survey widely used codes and their capabilities.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK129
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THPMK106	Architectural Considerations for Recirculated and Energy-Recovered Hard XFEL Drivers	FEL, linac, SRF, operation	4560
	D. Douglas, S.V. Benson, T. Powers, Y. Roblin, T. Satogata, C. Tennant JLab, Newport News, Virginia, USA D. Angal-Kalinin, N. Thompson, A.E. Wheelhouse, P.H. Williams STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom T.K. Charles CERN, Geneva, Switzerland R.C. York FRIB, East Lansing, Michigan, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. A confluence of events motivates discussion of design options for hard XFEL driver accelerators. Firstly, multiple superconducting radio-frequency (SRF) driven systems are now online (European XFEL), in construction (LCLS-II), or in design (MARIE); these provide increasing evidence of the transformational potential they offer for fundamental science with its concomitant benefits. Secondly, operation of 12 GeV CEBAF* validates use of recirculation in high energy SRF linacs. Thirdly, advances in the analysis and control of effects such as coherent synchrotron radiation (CSR) and the microbunching instability (uBI) have been recently achieved. Collectively, these developments offer insights providing extended facility science reach, reduced costs, multiplicity (i.e., support of numerous FELs operating over a range of wavelengths), and enhanced scalability and upgradability (to higher powers and energies). We will discuss the relationship amongst the various threads, and indicate how they inform design choices for the system architecture of an option for the UK-XFEL** - that of a staged multi-user X-ray FEL and nuclear physics facility based on a multi-pass recirculating SRF CW linac. M. Spata, "12 GeV CEBAF Initial Operations and Challenges", these proceedings. *P. Williams et al., Proc. FLS2018, Shanghai, China (March 2018).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK106
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THPML087	First ERL Operation of S-DALINAC and Commissioning of a Path Length Adjustment System	linac, operation, MMI, lattice	4859
	M. Arnold, C. Burandt, R. Grewe, J. Pforr, N. Pietralla, M. Steinhorst TU Darmstadt, Darmstadt, Germany C. Eschelbach, M. Lösler Frankfurt University of Applied Sciences, Frankfurt am Main, Germany F. Hug KPH, Mainz, Germany
	Funding: Work supported by DFG through GRK 2128 and INST163/383-1/FUGG The S-DALINAC is running in recirculating operation since 1991. In 2015/2016 a major upgrade was performed by adding a third recirculation beam line. The versatility of this recirculation beam line enables a phase shift of the beam of up to 360° of the RF phase. The required range of 10 cm for a 3 GHz RF frequency is realized by a path length adjustment system. A complementary operation in normal scheme (single-pass, once or thrice recirculating with acceleration) or ERL mode (once or twice) is possible by appropriate adjustment of this system. After installation this system was aligned properly and its functionality and stroke was checked without beam. The system was commissioned by measuring the change of the beam phase in dependency of the setting of the path length adjustment system. The complementary usage of the newly installed recirculation for once recirculating with acceleration and once recirculating with ERL mode has been shown successfully in autumn 2017. This contribution will provide an overview on the path length adjustment system and the first run of the once recirculating ERL mode of the S-DALINAC.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML087
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Paper

Title

Other Keywords

Page

THPAK129

Modeling Challenges for Energy Recovery Linacs With Long, High Charge Bunches

bunching, space-charge, electron, lattice

3544

C. Tennant
JLab, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Historically, nearly all energy recovery linacs (ERLs) built and operated were used to drive a free-electron laser (FEL). The requirement for high peak current bunches necessitates bunch compression and handling the attendant beam dynamical challenges. In recent years, ERLs have turned from being drivers of light sources toward applications for nuclear physics experiments, Compton backscattering sources and strong electron cooling. Unlike an FEL, these latter uses require long, high charge bunches with small energy spread. The electron bunch must maintain a small projected energy spread and therefore must avoid gross distortion due to CSR and longitudinal space charge over a single (or multiple) recirculations. Accurately modeling the relevant collective effects in the system 'space charge, microbunching instability, CSR and the effect of shielding' in addition to beam dynamical processes such as halo, presents a formidable challenge. Absent a code that models all of these effects, we outline an approach towards the design, analysis and optimization of the high-energy electron cooler for the Jefferson Lab Electron-Ion Collider and survey widely used codes and their capabilities.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK129

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPMK106

Architectural Considerations for Recirculated and Energy-Recovered Hard XFEL Drivers

FEL, linac, SRF, operation

4560

D. Douglas, S.V. Benson, T. Powers, Y. Roblin, T. Satogata, C. Tennant
JLab, Newport News, Virginia, USA
D. Angal-Kalinin, N. Thompson, A.E. Wheelhouse, P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
T.K. Charles
CERN, Geneva, Switzerland
R.C. York
FRIB, East Lansing, Michigan, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
A confluence of events motivates discussion of design options for hard XFEL driver accelerators. Firstly, multiple superconducting radio-frequency (SRF) driven systems are now online (European XFEL), in construction (LCLS-II), or in design (MARIE); these provide increasing evidence of the transformational potential they offer for fundamental science with its concomitant benefits. Secondly, operation of 12 GeV CEBAF* validates use of recirculation in high energy SRF linacs. Thirdly, advances in the analysis and control of effects such as coherent synchrotron radiation (CSR) and the microbunching instability (uBI) have been recently achieved. Collectively, these developments offer insights providing extended facility science reach, reduced costs, multiplicity (i.e., support of numerous FELs operating over a range of wavelengths), and enhanced scalability and upgradability (to higher powers and energies). We will discuss the relationship amongst the various threads, and indicate how they inform design choices for the system architecture of an option for the UK-XFEL** - that of a staged multi-user X-ray FEL and nuclear physics facility based on a multi-pass recirculating SRF CW linac.
*M. Spata, "12 GeV CEBAF Initial Operations and Challenges", these proceedings.
**P. Williams et al., Proc. FLS2018, Shanghai, China (March 2018).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK106

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPML087

First ERL Operation of S-DALINAC and Commissioning of a Path Length Adjustment System

linac, operation, MMI, lattice

4859

M. Arnold, C. Burandt, R. Grewe, J. Pforr, N. Pietralla, M. Steinhorst
TU Darmstadt, Darmstadt, Germany
C. Eschelbach, M. Lösler
Frankfurt University of Applied Sciences, Frankfurt am Main, Germany
F. Hug
KPH, Mainz, Germany

Funding: Work supported by DFG through GRK 2128 and INST163/383-1/FUGG
The S-DALINAC is running in recirculating operation since 1991. In 2015/2016 a major upgrade was performed by adding a third recirculation beam line. The versatility of this recirculation beam line enables a phase shift of the beam of up to 360° of the RF phase. The required range of 10 cm for a 3 GHz RF frequency is realized by a path length adjustment system. A complementary operation in normal scheme (single-pass, once or thrice recirculating with acceleration) or ERL mode (once or twice) is possible by appropriate adjustment of this system. After installation this system was aligned properly and its functionality and stroke was checked without beam. The system was commissioned by measuring the change of the beam phase in dependency of the setting of the path length adjustment system. The complementary usage of the newly installed recirculation for once recirculating with acceleration and once recirculating with ERL mode has been shown successfully in autumn 2017. This contribution will provide an overview on the path length adjustment system and the first run of the once recirculating ERL mode of the S-DALINAC.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML087

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)