HB2014 - List of Authors (Shaposhnikova, E.N.)

Paper

Title

Page

The High Luminosity Challenge: Potential and Limitations of High-Intensity High-Brightness Beams in the LHC and its Injectors

1

R. De Maria, G. Arduini, D. Banfi, J. Barranco, H. Bartosik, E. Benedetto, R. Bruce, O.S. Brüning, R. Calaga, F. Cerutti, H. Damerau, L.S. Esposito, S.D. Fartoukh, M. Fitterer, R. Garoby, S.S. Gilardoni, M. Giovannozzi, B. Goddard, B. Gorini, K. Hanke, G. Iadarola, M. Lamont, M. Meddahi, B. Mikulec, N. Mounet, E. Métral, Y. Papaphilippou, T. Pieloni, S. Redaelli, L. Rossi, G. Rumolo, E.N. Shaposhnikova, G. Sterbini, E. Todesco, R. Tomás, F. Zimmermann
CERN, Geneva, Switzerland
A. Valishev
Fermilab, Batavia, Illinois, USA

Funding: Research supported by EU FP7 HiLumi LHC - Grant Agreement 284404 and by DOE via the US-LARP program.
High-intensity and high-brightness beams are key ingredients to maximize the integrated luminosity of the LHC and exploit its full potential. This contribution will describe the optimization of the beam and machine parameters to maximize the integrated luminosity for the LHC experiments, by taking into account the expected intensity and brightness reach of the LHC and its injector chain and the capabilities of the detectors for the next run and foreseen upgrade scenarios.

Slides MOXLR01 [2.574 MB]

TUO1AB02

Upgrades of the RF Systems in the LHC Injector Complex

165

H. Damerau, M.E. Angoletta, T. Argyropoulos, P. Baudrenghien, A. Blas, T. Bohl, A.C. Butterworth, A. Findlay, R. Garoby, S.S. Gilardoni, S. Hancock, W. Höfle, J.C. Molendijk, E. Montesinos, M.M. Paoluzzi, D. Perrelet, C. Rossi, E.N. Shaposhnikova
CERN, Geneva, Switzerland

In the framework of the LHC Injector Upgrade (LIU) project the radio-frequency (RF) systems of the synchrotrons in the LHC injector chain will undergo significant improvements to reach the high beam intensity and quality required by the High-Luminosity (HL) LHC. Following the recent upgrade of the longitudinal beam control system in the PS Booster (PSB), tests with Finemet cavities are being performed in view of a complete replacement of the existing RF systems in the PSB by ones based on this technology. In the PS a similar wide-band Finemet cavity has been installed as a longitudinal damper. New 1-turn delay feedbacks on the main accelerating cavities to reduce their impedance have also been commissioned. Additional feedback and beam control improvements are foreseen. A major upgrade of the main RF system in the SPS by regrouping sections of its travelling wave cavities, increasing the number of cavities from four to six, will reduce beam-loading and allow higher intensities to be accelerated. The upgrade includes the installation of two new RF power plants and new feedback systems. All upgrades will be evaluated with respect to their expected benefits for the beams to the LHC.

Slides TUO1AB02 [4.317 MB]

THO1LR01

Long-term Beam Losses in the CERN Injector Chain

325

S.S. Gilardoni, G. Arduini, H. Bartosik, E. Benedetto, H. Damerau, V. Forte, M. Giovannozzi, B. Goddard, S. Hancock, K. Hanke, A. Huschauer, M. Kowalska, M. McAteer, M. Meddahi, B. Mikulec, E. Métral, Y. Papaphilippou, G. Rumolo, E.N. Shaposhnikova, G. Sterbini, R. Wasef
CERN, Geneva, Switzerland

For the production of the LHC type beams, but also for the high intensity ones, the budget allocated to losses in the CERN injector chain is maintained as tight as possible, in particular to keep as low as possible the activation of the different machine elements. Various beam dynamics effects, like for example beam interaction with betatronic resonances, beam instabilities, but also reduced efficiency of the RF capture processes or RF noise, can produce losses even on a very long time scale. The main different mechanisms producing long term losses observed in the CERN injectors, and their cure or mitigation, will be revised.

Slides THO1LR01 [5.913 MB]

THO4LR02

Synchrotron Frequency Shift as a Probe of the CERN SPS Reactive Impedance

409

A. Lasheen, T. Argyropoulos, J.V. Campelo, J.F. Esteban Müller, D. Quartullo, E.N. Shaposhnikova, H. Timko
CERN, Geneva, Switzerland

Longitudinal instability in the CERN SPS is a serious limitation for the future increase of bunch intensity required by HiLumi LHC project. The impedance driving this instability is not known precisely and a lot of effort goes into creating an accurate impedance model. The reactive impedance of the machine can be probed by measuring the bunch length oscillations of a mismatched bunch at injection. The frequency of these oscillations as a function of intensity has a slope that depends on the reactive impedance and the emittance. Measurements were done for three values of longitudinal emittances and then compared with particle simulations based on the impedance model using particle distribution close to the measured one. Comparison of measured and calculated frequency shifts gives an estimation of the missing impedance in the model. In addition, scanning of initial emittance for diverse particle distributions in simulations shows that the frequency shift greatly depends on emittance and initial distribution. Small variations of these parameters can lead to very different results and explain partially the discrepancy between measured and calculated values of frequency shifts.

Slides THO4LR02 [1.499 MB]

THO4LR03

Studies on Controlled RF Noise for the LHC

414

H. Timko, P. Baudrenghien, E.N. Shaposhnikova
CERN, Geneva, Switzerland
T. Mastoridis
CalPoly, San Luis Obispo, California, USA

RF phase noise is purposely injected into the LHC 400 MHz RF system during the acceleration ramp for controlled longitudinal emittance blow-up, in order to maintain longitudinal beam stability. Although the operational blow-up works reliably, studies of the injected RF noise are desirable not only to allow for a better-controlled, more flexible blow-up, but also for other applications such as the mitigation of machine-component heating through appropriate bunch shaping. Concerning the noise injection, an alternative algorithm was developed and implemented in the hardware, but first tests revealed unexpected modulation of the achieved bunch length along the ring, and subsequently, theoretical studies have been launched. In this paper, we present a summary of ongoing measurement analysis and simulation studies that shall explain previous observations, predict what can be expected in different cases, and thus help to optimise the RF noise in general.

Slides THO4LR03 [1.440 MB]

Paper	Title	Page
MOXLR01	The High Luminosity Challenge: Potential and Limitations of High-Intensity High-Brightness Beams in the LHC and its Injectors	1
	R. De Maria, G. Arduini, D. Banfi, J. Barranco, H. Bartosik, E. Benedetto, R. Bruce, O.S. Brüning, R. Calaga, F. Cerutti, H. Damerau, L.S. Esposito, S.D. Fartoukh, M. Fitterer, R. Garoby, S.S. Gilardoni, M. Giovannozzi, B. Goddard, B. Gorini, K. Hanke, G. Iadarola, M. Lamont, M. Meddahi, B. Mikulec, N. Mounet, E. Métral, Y. Papaphilippou, T. Pieloni, S. Redaelli, L. Rossi, G. Rumolo, E.N. Shaposhnikova, G. Sterbini, E. Todesco, R. Tomás, F. Zimmermann CERN, Geneva, Switzerland A. Valishev Fermilab, Batavia, Illinois, USA
	Funding: Research supported by EU FP7 HiLumi LHC - Grant Agreement 284404 and by DOE via the US-LARP program. High-intensity and high-brightness beams are key ingredients to maximize the integrated luminosity of the LHC and exploit its full potential. This contribution will describe the optimization of the beam and machine parameters to maximize the integrated luminosity for the LHC experiments, by taking into account the expected intensity and brightness reach of the LHC and its injector chain and the capabilities of the detectors for the next run and foreseen upgrade scenarios.
	Slides MOXLR01 [2.574 MB]

TUO1AB02	Upgrades of the RF Systems in the LHC Injector Complex	165
	H. Damerau, M.E. Angoletta, T. Argyropoulos, P. Baudrenghien, A. Blas, T. Bohl, A.C. Butterworth, A. Findlay, R. Garoby, S.S. Gilardoni, S. Hancock, W. Höfle, J.C. Molendijk, E. Montesinos, M.M. Paoluzzi, D. Perrelet, C. Rossi, E.N. Shaposhnikova CERN, Geneva, Switzerland
	In the framework of the LHC Injector Upgrade (LIU) project the radio-frequency (RF) systems of the synchrotrons in the LHC injector chain will undergo significant improvements to reach the high beam intensity and quality required by the High-Luminosity (HL) LHC. Following the recent upgrade of the longitudinal beam control system in the PS Booster (PSB), tests with Finemet cavities are being performed in view of a complete replacement of the existing RF systems in the PSB by ones based on this technology. In the PS a similar wide-band Finemet cavity has been installed as a longitudinal damper. New 1-turn delay feedbacks on the main accelerating cavities to reduce their impedance have also been commissioned. Additional feedback and beam control improvements are foreseen. A major upgrade of the main RF system in the SPS by regrouping sections of its travelling wave cavities, increasing the number of cavities from four to six, will reduce beam-loading and allow higher intensities to be accelerated. The upgrade includes the installation of two new RF power plants and new feedback systems. All upgrades will be evaluated with respect to their expected benefits for the beams to the LHC.
	Slides TUO1AB02 [4.317 MB]

THO1LR01	Long-term Beam Losses in the CERN Injector Chain	325
	S.S. Gilardoni, G. Arduini, H. Bartosik, E. Benedetto, H. Damerau, V. Forte, M. Giovannozzi, B. Goddard, S. Hancock, K. Hanke, A. Huschauer, M. Kowalska, M. McAteer, M. Meddahi, B. Mikulec, E. Métral, Y. Papaphilippou, G. Rumolo, E.N. Shaposhnikova, G. Sterbini, R. Wasef CERN, Geneva, Switzerland
	For the production of the LHC type beams, but also for the high intensity ones, the budget allocated to losses in the CERN injector chain is maintained as tight as possible, in particular to keep as low as possible the activation of the different machine elements. Various beam dynamics effects, like for example beam interaction with betatronic resonances, beam instabilities, but also reduced efficiency of the RF capture processes or RF noise, can produce losses even on a very long time scale. The main different mechanisms producing long term losses observed in the CERN injectors, and their cure or mitigation, will be revised.
	Slides THO1LR01 [5.913 MB]

THO4LR02	Synchrotron Frequency Shift as a Probe of the CERN SPS Reactive Impedance	409
	A. Lasheen, T. Argyropoulos, J.V. Campelo, J.F. Esteban Müller, D. Quartullo, E.N. Shaposhnikova, H. Timko CERN, Geneva, Switzerland
	Longitudinal instability in the CERN SPS is a serious limitation for the future increase of bunch intensity required by HiLumi LHC project. The impedance driving this instability is not known precisely and a lot of effort goes into creating an accurate impedance model. The reactive impedance of the machine can be probed by measuring the bunch length oscillations of a mismatched bunch at injection. The frequency of these oscillations as a function of intensity has a slope that depends on the reactive impedance and the emittance. Measurements were done for three values of longitudinal emittances and then compared with particle simulations based on the impedance model using particle distribution close to the measured one. Comparison of measured and calculated frequency shifts gives an estimation of the missing impedance in the model. In addition, scanning of initial emittance for diverse particle distributions in simulations shows that the frequency shift greatly depends on emittance and initial distribution. Small variations of these parameters can lead to very different results and explain partially the discrepancy between measured and calculated values of frequency shifts.
	Slides THO4LR02 [1.499 MB]

THO4LR03	Studies on Controlled RF Noise for the LHC	414
	H. Timko, P. Baudrenghien, E.N. Shaposhnikova CERN, Geneva, Switzerland T. Mastoridis CalPoly, San Luis Obispo, California, USA
	RF phase noise is purposely injected into the LHC 400 MHz RF system during the acceleration ramp for controlled longitudinal emittance blow-up, in order to maintain longitudinal beam stability. Although the operational blow-up works reliably, studies of the injected RF noise are desirable not only to allow for a better-controlled, more flexible blow-up, but also for other applications such as the mitigation of machine-component heating through appropriate bunch shaping. Concerning the noise injection, an alternative algorithm was developed and implemented in the hardware, but first tests revealed unexpected modulation of the achieved bunch length along the ring, and subsequently, theoretical studies have been launched. In this paper, we present a summary of ongoing measurement analysis and simulation studies that shall explain previous observations, predict what can be expected in different cases, and thus help to optimise the RF noise in general.
	Slides THO4LR03 [1.440 MB]