HB2018 - List of Authors (Lasheen, A.)

Paper	Title	Page
TUP2WA02	Momentum Slip-Stacking Simulations for CERN SPS Ion Beams with Collective Effects	174
	D. Quartullo, T. Argyropoulos, A. Lasheen CERN, Geneva, Switzerland
	The LHC Injectors Upgrade (LIU) Project at CERN aims at doubling the total intensity of the Pb-ion beam for the High-Luminosity LHC (HL-LHC) project. This goal can be achieved by using momentum slip-stacking (MSS) in the SPS, the LHC injector. This RF gymnastics, originally proposed to increase bunch intensity, will be used on the intermediate energy plateau to interleave two batches, reducing the bunch spacing from 100 to 50 ns. The MSS feasibility can be tested only in 2021, after the beam controls upgrade of the SPS 200 MHz RF system, so beam dynamics simulations are used to design this complicated beam manipulation. Simulations of the MSS were performed using the CERN BLonD code with a full SPS impedance model. Attention has been paid to the choice of the RF and machine parameters (beam energy, time duration, RF frequency and voltage programmes) to reduce losses and the final bunch length which is crucial for the injection into the LHC 400 MHz buckets. The initial beam parameters used in simulations were obtained from beam measurements in the first part of the SPS cycle taking into account bunch-by-bunch losses on flat bottom and development of bunch instabilities.
	Slides TUP2WA02 [8.272 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-TUP2WA02
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP2WA03	Studies of Capture and Flat-Bottom Losses in the SPS	180
	M. Schwarz, H. Bartosik, E. Chapochnikova, A. Lasheen, J. Repond, H. Timko CERN, Geneva, Switzerland
	One of the strong limitations for reaching higher beam intensities in the SPS, the injector of the LHC at CERN, are particle losses at flat bottom that increase with beam intensity. In this paper, different sources of these losses are investigated for two available SPS optics, using both measurements and simulations. Part of the losses originate from the PS-to-SPS bunch-to-bucket transfer, because the PS bunches are rotated in longitudinal phase space before injection and do not completely fit into the SPS RF bucket. The injection losses due to different injected bunch distributions were analyzed. Furthermore, at high intensities the transient beam loading in the SPS has a strong impact, which is (partially) compensated by the LLRF system. The effect of the present and future upgraded one-turn delay feedback system and phase loop on flat-bottom losses was studied using the longitudinal tracking code BLonD. Finally, the total particle losses are also affected by limitations in the SPS momentum aperture, visible for higher RF capture voltages in optics with lower transition energy and higher dispersion.
	Slides TUP2WA03 [8.038 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-TUP2WA03
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THA1WD04	High-Brightness Challenges for the Operation of the CERN Injector Complex	352
	K. Hanke, S.C.P. Albright, R. Alemany-Fernández, H. Bartosik, E. Chapochnikova, H. Damerau, G.P. Di Giovanni, B. Goddard, A. Huschauer, V. Kain, A. Lasheen, M. Meddahi, B. Mikulec, G. Rumolo, R. Scrivens, F. Tecker CERN, Geneva, Switzerland
	CERN's LHC injectors are delivering high-brightness proton and ion beams for the Large Hadron Collider LHC. We review the present operation modes and beam performance, and highlight the limitations. We will then give an overview of the upgrade program that has been put in place to meet the demands of the LHC during the High-Luminosity LHC era.
	Slides THA1WD04 [4.746 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-THA1WD04
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Momentum Slip-Stacking Simulations for CERN SPS Ion Beams with Collective Effects

174

D. Quartullo, T. Argyropoulos, A. Lasheen
CERN, Geneva, Switzerland

The LHC Injectors Upgrade (LIU) Project at CERN aims at doubling the total intensity of the Pb-ion beam for the High-Luminosity LHC (HL-LHC) project. This goal can be achieved by using momentum slip-stacking (MSS) in the SPS, the LHC injector. This RF gymnastics, originally proposed to increase bunch intensity, will be used on the intermediate energy plateau to interleave two batches, reducing the bunch spacing from 100 to 50 ns. The MSS feasibility can be tested only in 2021, after the beam controls upgrade of the SPS 200 MHz RF system, so beam dynamics simulations are used to design this complicated beam manipulation. Simulations of the MSS were performed using the CERN BLonD code with a full SPS impedance model. Attention has been paid to the choice of the RF and machine parameters (beam energy, time duration, RF frequency and voltage programmes) to reduce losses and the final bunch length which is crucial for the injection into the LHC 400 MHz buckets. The initial beam parameters used in simulations were obtained from beam measurements in the first part of the SPS cycle taking into account bunch-by-bunch losses on flat bottom and development of bunch instabilities.

Slides TUP2WA02 [8.272 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-TUP2WA02

Export •

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

TUP2WA03

Studies of Capture and Flat-Bottom Losses in the SPS

180

M. Schwarz, H. Bartosik, E. Chapochnikova, A. Lasheen, J. Repond, H. Timko
CERN, Geneva, Switzerland

One of the strong limitations for reaching higher beam intensities in the SPS, the injector of the LHC at CERN, are particle losses at flat bottom that increase with beam intensity. In this paper, different sources of these losses are investigated for two available SPS optics, using both measurements and simulations. Part of the losses originate from the PS-to-SPS bunch-to-bucket transfer, because the PS bunches are rotated in longitudinal phase space before injection and do not completely fit into the SPS RF bucket. The injection losses due to different injected bunch distributions were analyzed. Furthermore, at high intensities the transient beam loading in the SPS has a strong impact, which is (partially) compensated by the LLRF system. The effect of the present and future upgraded one-turn delay feedback system and phase loop on flat-bottom losses was studied using the longitudinal tracking code BLonD. Finally, the total particle losses are also affected by limitations in the SPS momentum aperture, visible for higher RF capture voltages in optics with lower transition energy and higher dispersion.

Slides TUP2WA03 [8.038 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-TUP2WA03

Export •

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

THA1WD04

High-Brightness Challenges for the Operation of the CERN Injector Complex

352

K. Hanke, S.C.P. Albright, R. Alemany-Fernández, H. Bartosik, E. Chapochnikova, H. Damerau, G.P. Di Giovanni, B. Goddard, A. Huschauer, V. Kain, A. Lasheen, M. Meddahi, B. Mikulec, G. Rumolo, R. Scrivens, F. Tecker
CERN, Geneva, Switzerland

CERN's LHC injectors are delivering high-brightness proton and ion beams for the Large Hadron Collider LHC. We review the present operation modes and beam performance, and highlight the limitations. We will then give an overview of the upgrade program that has been put in place to meet the demands of the LHC during the High-Luminosity LHC era.

Slides THA1WD04 [4.746 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-THA1WD04

Export •

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