COOL2021 - List of Authors (Gamba, D.)

Paper	Title	Page
S302	Recommissioning of the CERN AD Stochastic Cooling System in 2021 after Long Shutdown 2	20
	W. Höfle, C. Carli, F. Caspers, B. Dupuy, D. Gamba, R. Louwerse, V.R. Myklebust, J.C. Oliveira, L. Ponce, S.F. Rey, L. Thorndahl CERN, Meyrin, Switzerland
	The power system of the Stochastic Cooling System of the anti-proton decelerator AD at CERN, installed on top of the shielding blocks of the AD ring, was completely dismantled during the long shutdown 2 (LS2) at the end of the 2018 run in order to gain access to the accelerator for magnet consolidation. At start-up, this required finding and verifying the correct delays for all 48 power amplifiers feeding to the two kickers by means of beam transfer functions for the two cooling plateaus at 3.57 GeV/c and 2 GeV/c. We describe the methods used for the setting up and the results of the optimization for the cooling in all three planes, longitudinal, horizontal and vertical. An experimental set-up has been put into operation for the automatic monitoring and correction of the notch position of the longitudinal cooling at 3.57 GeV/c with optical delay lines. We also comment on the lessons learnt during the recommissioning including the repair work for a vacuum leak in the water cooling circuits of the kicker following bake-out and the verification of the internal loads by RF reflectometry.
	Slides S302 [9.736 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-COOL2021-S302
About •	paper received ※ 02 November 2021 paper accepted ※ 19 December 2021 issue date ※ 06 December 2021
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S503	AD/ELENA Electron Cooling Experience During and after CERNs Long Shutdown (LS2)	36
	D. Gamba, L. Bojtár, C. Carli, B. Dupuy, A. Frassier, L.V. Jørgensen, L. Ponce, G. Tranquille CERN, Geneva, Switzerland
	Electron cooling is a key ingredient of the Antimatter Factory at CERN, now composed of the AD and ELENA rings, both featuring an electron cooler. After the successful commissioning of the ELENA ring and electron cooling with antiprotons in 2018, the facility was shut down for the CERN long shutdown (LS2). In the meantime, ELENA has been operating with H⁻ ions generated from a local source, and electron cooling of H⁻ was demonstrated. The facility has restarted with antiproton operation during summer 2021, and it is now delivering 100 keV production beams through newly installed electro-static extraction lines to all the experiments for the very first time. We will give an overview of the experience gained and difficulties encountered during the restart of the AD and ELENA electron coolers. The experience with electron cooling of H⁻ beam in ELENA and the comparison with antiproton cooling will also be presented.
	Slides S503 [32.064 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-COOL2021-S503
About •	paper received ※ 03 November 2021 paper accepted ※ 01 December 2021 issue date ※ 07 December 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

P1005	Comparison of Available Models of Electron Cooling and Their Implementations	74
	A.E. Borucka Warsaw University of Technology, Warsaw, Poland A.E. Borucka, D. Gamba, A. Latina CERN, Geneva, Switzerland
	Modelling of the electron cooling process is complex and challenging. The simulation needs to include elements like ions, plasma of electrons, the thermal effects of electrons and the influence of the magnetic field. In this work, the performance of three available tools, namely RF-Track, Betacool, and JSPEC, are discussed taking into account only the cooling and neglecting any heating effect. The friction force and cooling times are studied in a wide range of different parameters presenting the main behaviour of the available models together with the limitations of particular simulation codes. Furthermore, a qualitative comparison with experimental data is performed.
	Poster P1005 [19.227 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-COOL2021-P1005
About •	paper received ※ 26 October 2021 paper accepted ※ 02 December 2021 issue date ※ 20 November 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Recommissioning of the CERN AD Stochastic Cooling System in 2021 after Long Shutdown 2

20

W. Höfle, C. Carli, F. Caspers, B. Dupuy, D. Gamba, R. Louwerse, V.R. Myklebust, J.C. Oliveira, L. Ponce, S.F. Rey, L. Thorndahl
CERN, Meyrin, Switzerland

The power system of the Stochastic Cooling System of the anti-proton decelerator AD at CERN, installed on top of the shielding blocks of the AD ring, was completely dismantled during the long shutdown 2 (LS2) at the end of the 2018 run in order to gain access to the accelerator for magnet consolidation. At start-up, this required finding and verifying the correct delays for all 48 power amplifiers feeding to the two kickers by means of beam transfer functions for the two cooling plateaus at 3.57 GeV/c and 2 GeV/c. We describe the methods used for the setting up and the results of the optimization for the cooling in all three planes, longitudinal, horizontal and vertical. An experimental set-up has been put into operation for the automatic monitoring and correction of the notch position of the longitudinal cooling at 3.57 GeV/c with optical delay lines. We also comment on the lessons learnt during the recommissioning including the repair work for a vacuum leak in the water cooling circuits of the kicker following bake-out and the verification of the internal loads by RF reflectometry.

Slides S302 [9.736 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-COOL2021-S302

About •

paper received ※ 02 November 2021 paper accepted ※ 19 December 2021 issue date ※ 06 December 2021

Export •

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

S503

AD/ELENA Electron Cooling Experience During and after CERNs Long Shutdown (LS2)

36

D. Gamba, L. Bojtár, C. Carli, B. Dupuy, A. Frassier, L.V. Jørgensen, L. Ponce, G. Tranquille
CERN, Geneva, Switzerland

Electron cooling is a key ingredient of the Antimatter Factory at CERN, now composed of the AD and ELENA rings, both featuring an electron cooler. After the successful commissioning of the ELENA ring and electron cooling with antiprotons in 2018, the facility was shut down for the CERN long shutdown (LS2). In the meantime, ELENA has been operating with H⁻ ions generated from a local source, and electron cooling of H⁻ was demonstrated. The facility has restarted with antiproton operation during summer 2021, and it is now delivering 100 keV production beams through newly installed electro-static extraction lines to all the experiments for the very first time. We will give an overview of the experience gained and difficulties encountered during the restart of the AD and ELENA electron coolers. The experience with electron cooling of H⁻ beam in ELENA and the comparison with antiproton cooling will also be presented.

Slides S503 [32.064 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-COOL2021-S503

About •

paper received ※ 03 November 2021 paper accepted ※ 01 December 2021 issue date ※ 07 December 2021

Export •

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

P1005

Comparison of Available Models of Electron Cooling and Their Implementations

74

A.E. Borucka
Warsaw University of Technology, Warsaw, Poland
A.E. Borucka, D. Gamba, A. Latina
CERN, Geneva, Switzerland

Modelling of the electron cooling process is complex and challenging. The simulation needs to include elements like ions, plasma of electrons, the thermal effects of electrons and the influence of the magnetic field. In this work, the performance of three available tools, namely RF-Track, Betacool, and JSPEC, are discussed taking into account only the cooling and neglecting any heating effect. The friction force and cooling times are studied in a wide range of different parameters presenting the main behaviour of the available models together with the limitations of particular simulation codes. Furthermore, a qualitative comparison with experimental data is performed.

Poster P1005 [19.227 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-COOL2021-P1005

About •

paper received ※ 26 October 2021 paper accepted ※ 02 December 2021 issue date ※ 20 November 2021

Export •

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