IPAC2021 - Table of Session: MOXC (Monday Oral Session C)

Paper	Title	Page
MOXC01	Combined Effect of Beam-Beam Interaction and Beam Coupling Impedance in Future Circular Colliders	25
	Y. Zhang, N. Wang IHEP, Beijing, People’s Republic of China E. Carideo CERN, Geneva, Switzerland M. Migliorati SBAI, Roma, Italy M. Zobov INFN/LNF, Frascati, Italy
	Funding: This work is supported by National Key Programme for S&T Research and Development, China (Grant No. 2016YFA0400400), National Natural Science Foundation of China (No. 11775238, No. 11775239). The future large scale electron-positron colliders, such as FCC-ee in Europe and CEPC in China, will rely on the crab waist collision scheme with a large Piwinski angle. Differently from the past generation colliders both luminosity and beam-beam tune shifts depend on the bunch length in such a collision scheme. In addition, for the future circular colliders with extreme beam parameters in collision several new effects become important such as beamstrahlung, coherent X-Z instability and 3D flip-flop. For all these effects the longitudinal beam dynamics plays an essential role and should be taken into account for the collider luminosity optimization. In this paper we discuss an impact of the longitudinal beam coupling impedance on the collider performance.
	Slides MOXC01 [2.269 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOXC01
About •	paper received ※ 17 May 2021 paper accepted ※ 27 July 2021 issue date ※ 17 August 2021
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MOXC02	Improved Lifetime of a High Spin Polarization Superlattice Photocathode	31
	L. Cultrera BNL, Upton, New York, USA
	Funding: Department of Energy under grant DE-SC0012704 Highly spin polarized electron beams are required for the operation of a wide range of accelerators and instruments. The production of such electrons requires the use of Negative Electron Affinity (NEA) activated GaAs-based cathodes operated in photoelectron guns. Because of their extreme sensitivity to poor vacuum conditions the degradation of the photoemission process is so strong that NEA activated GaAs-based photocathodes can only survive in the extreme vacuums typical of DC gun. State-of-the-art on photocathode technology for spin polarized beam productions are summarized. Recent results on the use of robust NEA coating based on the Cs-Te and Cs-Sb leading to improved operational lifetime of a high spin polarization photocathode are reviewed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOXC02
About •	paper received ※ 20 May 2021 paper accepted ※ 19 July 2021 issue date ※ 19 August 2021
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MOXC03	The Interstellar Space in an Electrostatic Cryogenic Storage Ring
	R. von Hahn MPI-K, Heidelberg, Germany
	Traditionally, particle accelerators have been built to provide increasingly high energies and intensities to reproduce the very first moments of our Universe after the Big Bang to investigate for example the formation of the building blocks of matter. In the last decade, however, the interest also focuses on the formation and dynamics of molecules in the early and today’s Universe, which places completely different demands on particle accelerators. High energies are not needed. Instead, they have to provide near to interstellar conditions such as an ultrahigh vacuum of or less than 1E-14 mbar and cryogenically cooled environments for the stored particles. This allows extremely long observation periods to investigate quantum state properties and opens up completely new insights in different fields of physics. The electrostatic cryogenic storage ring CSR at the Max Planck Institute for Nuclear Physics in Heidelberg was conceived, designed and constructed to achieve these goals and is successfully in operation since 2015. This talk will sum up motivation, design, construction and first results obtained with the CSR, a worldwide unique machine with great new opportunities.
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Paper

Title

Page

Combined Effect of Beam-Beam Interaction and Beam Coupling Impedance in Future Circular Colliders

25

Y. Zhang, N. Wang
IHEP, Beijing, People’s Republic of China
E. Carideo
CERN, Geneva, Switzerland
M. Migliorati
SBAI, Roma, Italy
M. Zobov
INFN/LNF, Frascati, Italy

Funding: This work is supported by National Key Programme for S&T Research and Development, China (Grant No. 2016YFA0400400), National Natural Science Foundation of China (No. 11775238, No. 11775239).
The future large scale electron-positron colliders, such as FCC-ee in Europe and CEPC in China, will rely on the crab waist collision scheme with a large Piwinski angle. Differently from the past generation colliders both luminosity and beam-beam tune shifts depend on the bunch length in such a collision scheme. In addition, for the future circular colliders with extreme beam parameters in collision several new effects become important such as beamstrahlung, coherent X-Z instability and 3D flip-flop. For all these effects the longitudinal beam dynamics plays an essential role and should be taken into account for the collider luminosity optimization. In this paper we discuss an impact of the longitudinal beam coupling impedance on the collider performance.

Slides MOXC01 [2.269 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOXC01

About •

paper received ※ 17 May 2021 paper accepted ※ 27 July 2021 issue date ※ 17 August 2021

Export •

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

MOXC02

Improved Lifetime of a High Spin Polarization Superlattice Photocathode

31

L. Cultrera
BNL, Upton, New York, USA

Funding: Department of Energy under grant DE-SC0012704
Highly spin polarized electron beams are required for the operation of a wide range of accelerators and instruments. The production of such electrons requires the use of Negative Electron Affinity (NEA) activated GaAs-based cathodes operated in photoelectron guns. Because of their extreme sensitivity to poor vacuum conditions the degradation of the photoemission process is so strong that NEA activated GaAs-based photocathodes can only survive in the extreme vacuums typical of DC gun. State-of-the-art on photocathode technology for spin polarized beam productions are summarized. Recent results on the use of robust NEA coating based on the Cs-Te and Cs-Sb leading to improved operational lifetime of a high spin polarization photocathode are reviewed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOXC02

About •

paper received ※ 20 May 2021 paper accepted ※ 19 July 2021 issue date ※ 19 August 2021

Export •

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

MOXC03

The Interstellar Space in an Electrostatic Cryogenic Storage Ring

R. von Hahn
MPI-K, Heidelberg, Germany

Traditionally, particle accelerators have been built to provide increasingly high energies and intensities to reproduce the very first moments of our Universe after the Big Bang to investigate for example the formation of the building blocks of matter. In the last decade, however, the interest also focuses on the formation and dynamics of molecules in the early and today’s Universe, which places completely different demands on particle accelerators. High energies are not needed. Instead, they have to provide near to interstellar conditions such as an ultrahigh vacuum of or less than 1E-14 mbar and cryogenically cooled environments for the stored particles. This allows extremely long observation periods to investigate quantum state properties and opens up completely new insights in different fields of physics. The electrostatic cryogenic storage ring CSR at the Max Planck Institute for Nuclear Physics in Heidelberg was conceived, designed and constructed to achieve these goals and is successfully in operation since 2015. This talk will sum up motivation, design, construction and first results obtained with the CSR, a worldwide unique machine with great new opportunities.

Export •

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