HB2018 - List of Keywords (optics)

Paper	Title	Other Keywords	Page
MOP2WA04	Recent Results from the Wideband Feedback System Tests at the SPS and Future Plans	feedback, kicker, coupling, controls	38
	K.S.B. Li, H. Bartosik, M.S. Beck, E.R. Bjørsvik, W. Höfle, G. Kotzian, T.E. Levens, M. Schenk CERN, Geneva, Switzerland J.E. Dusatko, J.D. Fox, C.H. Rivetta SLAC, Menlo Park, California, USA M. Schenk EPFL, Lausanne, Switzerland O. Turgut Stanford University, Stanford, California, USA
	A high bandwidth transverse feedback demonstrator system has been devised within the LARP framework in collaboration with SLAC for the LHC Injectors Upgrade (LIU) Project. The initial system targeted the Super Proton Synchrotron (SPS) at CERN to combat TMCI and electron cloud instabilities induced for bunches with bunch lengths at the 100 MHz scale. It features a very fast digital signal processing system running at up to 4~GS/s and high bandwidth kickers with a frequency reach of ultimately beyond 1~GHz. In recent years, the system has gradually been extended and now includes two stripline kickers for a total power of 1~kW delivering correction signals at frequencies of currently more than 700~MHz. This talk will cover recent studies using this demonstrator system to overcome TMCI limitations in the SPS. We will conclude with future plans and also briefly mention potential applications and requirements for larger machines such as the LHC or the HL-LHC.
	Slides MOP2WA04 [19.091 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-MOP2WA04
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOP1WB03	Experimental Study of Beam Dynamics in the PIP-II MEBT Prototype	rfq, cavity, emittance, simulation	54
	A.V. Shemyakin, J.-P. Carneiro, B.M. Hanna, V.A. Lebedev, L.R. Prost, A. Saini, V.E. Scarpine Fermilab, Batavia, Illinois, USA C.J. Richard NSCL, East Lansing, Michigan, USA V.L. Sista BARC, Mumbai, India
	Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics The Proton Improvement Plan, Stage Two (PIP-II) is a program of upgrades proposed for the Fermilab injection complex, which central part is an 800-MeV, 2-mA CW SRF linac. A prototype of the PIP-II linac front end called PIP-II Injector Test (PIP2IT) is being built at Fermilab. As of now, a 15-mA DC, 30-keV H⁻ ion source, a 2 m-long Low Energy Beam Transport (LEBT), a 2.1-MeV CW RFQ, followed by a 10-m Medium Energy Beam Transport (MEBT) have been assembled and commissioned. The MEBT bunch-by-bunch chopping system and the requirement of a low uncontrolled beam loss put stringent limitations on the beam envelope and its variation. Measurements of transverse and longitudinal beam dynamics in the MEBT were performed in the range of 1-10 mA of the RFQ beam current. Almost all measurements are made with 10 μs beam pulses in order to avoid damage to the beam line. This report presents measurements of the transverse optics with differential trajectories, reconstruction of the beam envelope with scrapers and an Allison emittance scanner, as well as bunch length measurements with a Fast Faraday Cup.
	Slides MOP1WB03 [3.750 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-MOP1WB03
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP2WA01	Optical Stochastic Cooling Experiment at the Fermilab IOTA Ring	undulator, electron, radiation, experiment	168
	J.D. Jarvis, V.A. Lebedev, H. Piekarz, P. Piot, A.L. Romanov, J. Ruan Fermilab, Batavia, Illinois, USA M.B. Andorf, P. Piot Northern Illinois University, DeKalb, Illinois, USA
	Funding: Fermi National Accelerator Laboratory is operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy. Beam cooling enables an increase of peak and average luminosities and significantly expands the discovery potential of colliders; therefore it is an indispensable component of any modern design. Optical Stochastic Cooling (OSC) is a high-bandwidth, beam-cooling technique that will advance the present state-of-the-art, stochastic cooling rate by more than three orders of magnitude. It is an enabling technology for next-generation, discovery-science machines at the energy and intensity frontiers including hadron and electron-ion colliders. This paper presents the status of our experimental effort to demonstrate OSC at the Integrable Optics Test Accelerator (IOTA) ring, a testbed for advanced beam-physics concepts and technologies that is currently being commissioned at Fermilab. Our recent efforts are centered on the development of an integrated design that is prepared for final engineering and fabrication. The paper also presents a comparison of theoretical calculations and numerical simulations of the pickup-undulator radiation and its interaction with electrons in the kicker-undulator.
	Slides TUP2WA01 [20.009 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-TUP2WA01
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP2WA03	Studies of Capture and Flat-Bottom Losses in the SPS	simulation, impedance, injection, beam-loading	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)

WEP1WA03	IBS Near Transition Crossing in NICA Collider	collider, emittance, lattice, focusing	252
	S.A. Kostromin, A.O. Sidorin JINR, Dubna, Moscow Region, Russia I.V. Gorelyshev JINR/VBLHEP, Dubna, Moscow region, Russia V.A. Lebedev Fermilab, Batavia, Illinois, USA A.O. Sidorin Saint Petersburg State University, Saint Petersburg, Russia
	Intrabeam scattering (IBS) of charged particles in a particle beam results in an exchange of energy between different degrees of freedom. That results in an increase of average energy of particles in the beam frame and an increase of the 3D-emittance. The paper considers calculations of beam emittance growth rates for different options of NICA collider and IBS effects in close vicinity of the transition.
	Slides WEP1WA03 [1.774 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-WEP1WA03
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEP2PO006	Overview of the CERN PSB-to-PS Transfer Line Optics Matching Studies in View of the LHC Injectors Upgrade Project	emittance, operation, injection, quadrupole	272
	V. Forte, S.C.P. Albright, W. Bartmann, G.P. Di Giovanni, M.A. Fraser, C. Heßler, A. Huschauer, A. Oeftiger CERN, Geneva, Switzerland
	At injection into the CERN Proton Synchrotron (PS) a significant horizontal emittance blow-up of the present high brightness beams for the LHC is observed. A partial contribution to this effect is suspected to be an important mismatch between the dispersion function in the transfer line from the PS Booster (PSB) and the ring itself. This mismatch will be unacceptable in view of the beam parameters requested by the LHC Injectors Upgrade (LIU) project with high longitudinal emittance and momentum spread. To deliver the requested beam parameters the PSB-to-PS transfer line will be upgraded and the optics in the line changed to improve the matching from all the four PSB rings. A re-matching campaign from the PSB ring 3 has been carried out to evaluate the impact of the present optics mismatch as a source of emittance growth both in simulations and measurements.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-WEP2PO006
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEP2PO007	Multi-Particle Simulations of the Future CERN PSB Injection Process with Updated Linac4 Beam Performance	injection, linac, emittance, simulation	278
	V. Forte, C. Bracco, G.P. Di Giovanni, M.A. Fraser, A.M. Lombardi, B. Mikulec CERN, Geneva, Switzerland
	In the framework of the LHC Injectors Upgrade (LIU) project, the injection process in the CERN Proton Synchrotron Booster (PSB) will be renovated after the connection with the Linac4. A new H⁻ charge exchange injection system using a stripping foil is foreseen to increase the brightness of the stored beams and to provide high flexibility in terms of emittance tailoring at 160 MeV. Realistic multi-particle simulations of the future injection processes for high brightness beams (i.e. for the LHC) and high intensity beams (i.e. for the ISOLDE experiment) are presented in this paper. The simulations are based on the present performance of Linac4 and include scattering induced by the foil, space charge effects and compensation of the lattice perturbation introduced by the bumpers of the injection chicane.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-WEP2PO007
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEP2PO008	SPS Long Term Stability Studies in the Presence of Crab Cavities and High Order Multipoles	multipole, cavity, luminosity, sextupole	284
	A. Alekou, H. Bartosik, R. Calaga, M. Carlà, Y. Papaphilippou CERN, Geneva, Switzerland R.B. Appleby, R.B. Appleby UMAN, Manchester, United Kingdom R.B. Appleby Cockcroft Institute, Warrington, Cheshire, United Kingdom
	A local Crab Cavity (CC) scheme will recover the head-on collisions at the IP of the High Luminosity LHC (HL-LHC), which aims to increase the LHC luminosity by a factor of 3-10. The tight space constraints at the CC location result in axially non-symmetric cavity designs that introduce high order multipole CC components. The impact of these high order components on the long term stability of the beam in the SPS machine, where two prototype crab cavities are presently installed in the CERN SPS to perform tests with beam, is presented. Furthermore, the Dynamic Aperture is studied in the presence of the SPS errors. Future plans are discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-WEP2PO008
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WEP2PO011	Studies of Transverse Instabilities in the CERN SPS	emittance, simulation, octupole, injection	291
	M.S. Beck, H. Bartosik, M. Carlà, K.S.B. Li, G. Rumolo, M. Schenk CERN, Geneva, Switzerland U. van Rienen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
	In the framework of the LHC Injectors Upgrade (LIU), beams with about twice the intensity compared to the present values will have to be accelerated by the CERN Super Proton Synchrotron (SPS) and extracted towards the Large Hadron Collider (LHC). Machine studies with intensity higher than the nominal LHC beam have shown that coherent instabilities in both transverse planes may develop at injection energy, potentially becoming a limitation for the future high intensity operation. In particular, a transverse mode coupling instability is encountered in the vertical plane, the threshold of which can be sufficiently increased by changing the machine optics. In addition, a headtail instability of individual bunches is observed in the horizontal plane in multi-bunch operation, which requires stabilization by high chromaticity. The PyHEADTAIL code has been used to check if the present SPS impedance model reproduces the experimental observations. The instability growth rates have been studied for different machine optics configurations and different chromaticity settings. Other stabilizing mechanisms like tune spread from octupoles or the transverse damper have also been investigated.
	Poster WEP2PO011 [4.940 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-WEP2PO011
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

MOP2WA04

Recent Results from the Wideband Feedback System Tests at the SPS and Future Plans

feedback, kicker, coupling, controls

38

K.S.B. Li, H. Bartosik, M.S. Beck, E.R. Bjørsvik, W. Höfle, G. Kotzian, T.E. Levens, M. Schenk
CERN, Geneva, Switzerland
J.E. Dusatko, J.D. Fox, C.H. Rivetta
SLAC, Menlo Park, California, USA
M. Schenk
EPFL, Lausanne, Switzerland
O. Turgut
Stanford University, Stanford, California, USA

A high bandwidth transverse feedback demonstrator system has been devised within the LARP framework in collaboration with SLAC for the LHC Injectors Upgrade (LIU) Project. The initial system targeted the Super Proton Synchrotron (SPS) at CERN to combat TMCI and electron cloud instabilities induced for bunches with bunch lengths at the 100 MHz scale. It features a very fast digital signal processing system running at up to 4~GS/s and high bandwidth kickers with a frequency reach of ultimately beyond 1~GHz. In recent years, the system has gradually been extended and now includes two stripline kickers for a total power of 1~kW delivering correction signals at frequencies of currently more than 700~MHz. This talk will cover recent studies using this demonstrator system to overcome TMCI limitations in the SPS. We will conclude with future plans and also briefly mention potential applications and requirements for larger machines such as the LHC or the HL-LHC.

Slides MOP2WA04 [19.091 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-MOP2WA04

Export •

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

MOP1WB03

Experimental Study of Beam Dynamics in the PIP-II MEBT Prototype

rfq, cavity, emittance, simulation

54

A.V. Shemyakin, J.-P. Carneiro, B.M. Hanna, V.A. Lebedev, L.R. Prost, A. Saini, V.E. Scarpine
Fermilab, Batavia, Illinois, USA
C.J. Richard
NSCL, East Lansing, Michigan, USA
V.L. Sista
BARC, Mumbai, India

Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics
The Proton Improvement Plan, Stage Two (PIP-II) is a program of upgrades proposed for the Fermilab injection complex, which central part is an 800-MeV, 2-mA CW SRF linac. A prototype of the PIP-II linac front end called PIP-II Injector Test (PIP2IT) is being built at Fermilab. As of now, a 15-mA DC, 30-keV H⁻ ion source, a 2 m-long Low Energy Beam Transport (LEBT), a 2.1-MeV CW RFQ, followed by a 10-m Medium Energy Beam Transport (MEBT) have been assembled and commissioned. The MEBT bunch-by-bunch chopping system and the requirement of a low uncontrolled beam loss put stringent limitations on the beam envelope and its variation. Measurements of transverse and longitudinal beam dynamics in the MEBT were performed in the range of 1-10 mA of the RFQ beam current. Almost all measurements are made with 10 μs beam pulses in order to avoid damage to the beam line. This report presents measurements of the transverse optics with differential trajectories, reconstruction of the beam envelope with scrapers and an Allison emittance scanner, as well as bunch length measurements with a Fast Faraday Cup.

Slides MOP1WB03 [3.750 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-MOP1WB03

Export •

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

TUP2WA01

Optical Stochastic Cooling Experiment at the Fermilab IOTA Ring

undulator, electron, radiation, experiment

168

J.D. Jarvis, V.A. Lebedev, H. Piekarz, P. Piot, A.L. Romanov, J. Ruan
Fermilab, Batavia, Illinois, USA
M.B. Andorf, P. Piot
Northern Illinois University, DeKalb, Illinois, USA

Funding: Fermi National Accelerator Laboratory is operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
Beam cooling enables an increase of peak and average luminosities and significantly expands the discovery potential of colliders; therefore it is an indispensable component of any modern design. Optical Stochastic Cooling (OSC) is a high-bandwidth, beam-cooling technique that will advance the present state-of-the-art, stochastic cooling rate by more than three orders of magnitude. It is an enabling technology for next-generation, discovery-science machines at the energy and intensity frontiers including hadron and electron-ion colliders. This paper presents the status of our experimental effort to demonstrate OSC at the Integrable Optics Test Accelerator (IOTA) ring, a testbed for advanced beam-physics concepts and technologies that is currently being commissioned at Fermilab. Our recent efforts are centered on the development of an integrated design that is prepared for final engineering and fabrication. The paper also presents a comparison of theoretical calculations and numerical simulations of the pickup-undulator radiation and its interaction with electrons in the kicker-undulator.

Slides TUP2WA01 [20.009 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-TUP2WA01

Export •

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

TUP2WA03

Studies of Capture and Flat-Bottom Losses in the SPS

simulation, impedance, injection, beam-loading

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)

WEP1WA03

IBS Near Transition Crossing in NICA Collider

collider, emittance, lattice, focusing

252

S.A. Kostromin, A.O. Sidorin
JINR, Dubna, Moscow Region, Russia
I.V. Gorelyshev
JINR/VBLHEP, Dubna, Moscow region, Russia
V.A. Lebedev
Fermilab, Batavia, Illinois, USA
A.O. Sidorin
Saint Petersburg State University, Saint Petersburg, Russia

Intrabeam scattering (IBS) of charged particles in a particle beam results in an exchange of energy between different degrees of freedom. That results in an increase of average energy of particles in the beam frame and an increase of the 3D-emittance. The paper considers calculations of beam emittance growth rates for different options of NICA collider and IBS effects in close vicinity of the transition.

Slides WEP1WA03 [1.774 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-WEP1WA03

Export •

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

WEP2PO006

Overview of the CERN PSB-to-PS Transfer Line Optics Matching Studies in View of the LHC Injectors Upgrade Project

emittance, operation, injection, quadrupole

272

V. Forte, S.C.P. Albright, W. Bartmann, G.P. Di Giovanni, M.A. Fraser, C. Heßler, A. Huschauer, A. Oeftiger
CERN, Geneva, Switzerland

At injection into the CERN Proton Synchrotron (PS) a significant horizontal emittance blow-up of the present high brightness beams for the LHC is observed. A partial contribution to this effect is suspected to be an important mismatch between the dispersion function in the transfer line from the PS Booster (PSB) and the ring itself. This mismatch will be unacceptable in view of the beam parameters requested by the LHC Injectors Upgrade (LIU) project with high longitudinal emittance and momentum spread. To deliver the requested beam parameters the PSB-to-PS transfer line will be upgraded and the optics in the line changed to improve the matching from all the four PSB rings. A re-matching campaign from the PSB ring 3 has been carried out to evaluate the impact of the present optics mismatch as a source of emittance growth both in simulations and measurements.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-WEP2PO006

Export •

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

WEP2PO007

Multi-Particle Simulations of the Future CERN PSB Injection Process with Updated Linac4 Beam Performance

injection, linac, emittance, simulation

278

V. Forte, C. Bracco, G.P. Di Giovanni, M.A. Fraser, A.M. Lombardi, B. Mikulec
CERN, Geneva, Switzerland

In the framework of the LHC Injectors Upgrade (LIU) project, the injection process in the CERN Proton Synchrotron Booster (PSB) will be renovated after the connection with the Linac4. A new H⁻ charge exchange injection system using a stripping foil is foreseen to increase the brightness of the stored beams and to provide high flexibility in terms of emittance tailoring at 160 MeV. Realistic multi-particle simulations of the future injection processes for high brightness beams (i.e. for the LHC) and high intensity beams (i.e. for the ISOLDE experiment) are presented in this paper. The simulations are based on the present performance of Linac4 and include scattering induced by the foil, space charge effects and compensation of the lattice perturbation introduced by the bumpers of the injection chicane.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-WEP2PO007

Export •

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

WEP2PO008

SPS Long Term Stability Studies in the Presence of Crab Cavities and High Order Multipoles

multipole, cavity, luminosity, sextupole

284

A. Alekou, H. Bartosik, R. Calaga, M. Carlà, Y. Papaphilippou
CERN, Geneva, Switzerland
R.B. Appleby, R.B. Appleby
UMAN, Manchester, United Kingdom
R.B. Appleby
Cockcroft Institute, Warrington, Cheshire, United Kingdom

A local Crab Cavity (CC) scheme will recover the head-on collisions at the IP of the High Luminosity LHC (HL-LHC), which aims to increase the LHC luminosity by a factor of 3-10. The tight space constraints at the CC location result in axially non-symmetric cavity designs that introduce high order multipole CC components. The impact of these high order components on the long term stability of the beam in the SPS machine, where two prototype crab cavities are presently installed in the CERN SPS to perform tests with beam, is presented. Furthermore, the Dynamic Aperture is studied in the presence of the SPS errors. Future plans are discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-WEP2PO008

Export •

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

WEP2PO011

Studies of Transverse Instabilities in the CERN SPS

emittance, simulation, octupole, injection

291

M.S. Beck, H. Bartosik, M. Carlà, K.S.B. Li, G. Rumolo, M. Schenk
CERN, Geneva, Switzerland
U. van Rienen
Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany

In the framework of the LHC Injectors Upgrade (LIU), beams with about twice the intensity compared to the present values will have to be accelerated by the CERN Super Proton Synchrotron (SPS) and extracted towards the Large Hadron Collider (LHC). Machine studies with intensity higher than the nominal LHC beam have shown that coherent instabilities in both transverse planes may develop at injection energy, potentially becoming a limitation for the future high intensity operation. In particular, a transverse mode coupling instability is encountered in the vertical plane, the threshold of which can be sufficiently increased by changing the machine optics. In addition, a headtail instability of individual bunches is observed in the horizontal plane in multi-bunch operation, which requires stabilization by high chromaticity. The PyHEADTAIL code has been used to check if the present SPS impedance model reproduces the experimental observations. The instability growth rates have been studied for different machine optics configurations and different chromaticity settings. Other stabilizing mechanisms like tune spread from octupoles or the transverse damper have also been investigated.

Poster WEP2PO011 [4.940 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-WEP2PO011

Export •

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