IPAC2017 - List of Authors (Valuch, D.)

Paper	Title	Page
MOPAB113	Usage of the Transverse Damper Observation Box for High Sampling Rate Transverse Position Data in the LHC	389
	L.R. Carver, X. Buffat, A.C. Butterworth, W. Höfle, G. Iadarola, G. Kotzian, K.S.B. Li, E. Métral, M. Ojeda Sandonís, M.E. Söderén, D. Valuch CERN, Geneva, Switzerland
	The transverse damper observation box (ADTObsBox) is a device that makes accessible the bunch-by-bunch turn-by-turn data recorded from the pickups of the LHC transverse damper. This device can provide online transient analysis of different beam dynamics effects (tunes and damping times at injection, for example), while also under development is an online coherent instability triggering system. This paper will provide an overview of the current setup and plans for future upgrades, as well as detailing how it deals with the large volume of data being generated. The results of some analysis that rely on the ADTObsBox will also be shown.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB113
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MOPAB117	Online Bunch by Bunch Transverse Instability Detection in LHC	397
	M.E. Söderén, G. Kotzian, M. Ojeda Sandonís, D. Valuch CERN, Geneva, Switzerland
	Reliable detection of developing transverse instabilities in the Large Hadron Collider is one of the main operational challenges of the LHC's high intensity proton run. A full machine snapshot provided from the moment of instability is a crucial input to develop and fine tune instability models. The transverse feedback system (ADT) is the only instrument in LHC, where a full rate bunch by bunch transverse position information is available. Together with a sub-micron resolution it makes it a perfect place to detect transverse beam motion. Very large amounts of data, at very high data rates (8 Gb/s) need to be processed on the fly to detect onset of transverse instability. A very powerful computer system (so called ADTObsBox) was developed and put into operation by the CERN RF group, which is capable of processing the full rate data streams from ADT and perform an on the fly instability detection. The output of this system is a timing event with a list of all bunches developing instability, which is then sent to the LHC-wide instability trigger network to freeze other observation instruments. The device also provides buffers with raw position data for offline analysis.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB117
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TUPIK093	Sensitivity of the LHC Transverse Feedback System to Intra-Bunch Motion	1916
	G. Kotzian, W. Höfle, D. Valuch CERN, Geneva, Switzerland
	The LHC Transverse Feedback System is designed to damp and counteract all possible coupled bunch modes between the lowest betatron frequency and 20 MHz. The present study reveals that the analogue frontend processing scheme based on down converting the pick-up signal at the LHC RF frequency to baseband considerably extends the detected bunch movements visible to the feedback system to beyond 1 GHz. We develop an analytical model of the signal processing chain to explore the impact of even-symmetric and odd-symmetric intra-bunch movements on the detected beam position as a function of the longitudinal bunch shape. A set of equations is derived suitable for numerical simulations, or as a complement in particle tracking codes to further refine the behaviour of the LHC transverse feedback system.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPIK093
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TUPVA007	Impact of LHC and SPS Injection Kicker Rise Times on Lhc Filling Schemes and Luminosity Reach	2043
	W. Bartmann, M.J. Barnes, J. Boyd, E. Carlier, A. Chmielinska, B. Goddard, G. Kotzian, C. Schwick, L.S. Stoel, D. Valuch, F.M. Velotti, V. Vlachodimitropoulos, C. Wiesner CERN, Geneva, Switzerland
	The 2016 LHC proton filling schemes generally used a spacing between injections of batches of bunches into SPS and LHC corresponding to the design report specification for the SPS and LHC injection kicker rise times, respectively. A reduction of the batch spacing can be directly used to increase luminosity without detrimental effects on beam stability, and with no increase in the number of events per crossing seen by the experiments. Measurements and simulations were performed in SPS and LHC to understand if a shorter injection kicker rise time and associated tighter batch spacing would lead to increased injection oscillations of the first and last bunches of a bunch train and eventually also a systematic growth of the transverse emittance. The results were used to define the minimum possible batch spacing for an acceptable emittance growth in LHC, with gains of reductions of about 10% possible in both machines. The results are discussed, including the potential improvement of the LHC luminosity for different filling schemes.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA007
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TUPVA029	Observations of Emittance Growth in the Presence of External Noise in the LHC	2117
	X. Buffat, C. Tambasco, D. Valuch CERN, Geneva, Switzerland J. Barranco García, T. Pieloni, C. Tambasco EPFL, Lausanne, Switzerland
	Dedicated experiments were perfomed in the LHC to study the impact of noise on colliding high brightness beams. The results are compared to theoretical models and multiparticle tracking simulations. The impacts on the LHC operation and the HL-LHC project are discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA029
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WEOAA2	Status of Radioactive Ion Beam Post-Acceleration at CERN-ISOLDE	2466
	Y. Kadi, W. Andreazza, J. Bauche, A. Behrens, A.P. Bernardes, J.A. Ferreira Somoza, F. Formenti, M.A. Fraser, M.J. Garcia Borge, N. Guillotin, K. Johnston, G. Kautzmann, Y. Leclercq, M. Martino, A. Miyazaki, R. Mompo, A. Papageorgiou Koufidou, O. Pirotte, J.A. Rodriguez, S. Sadovich, E. Siesling, M. Therasse, D. Valuch, W. Venturini Delsolaro CERN, Geneva, Switzerland
	Funding: We acknowledge funding from the Belgian Big Science program of the FWO (Research Foundation Flanders) and the Research Council K.U. Leuven. The HIE-ISOLDE project* (High Intensity and Energy ISOLDE) reached an important milestone in September 2016 when the first physics run was carried out with radioactive beams at 6 MV/m. This is the first stage in the upgrade of the REX post-accelerator, whereby the energy of the radioactive ion beams was increased from 3 to 5.5 MeV per nucleon. The facility will ultimately be equipped with four high-beta cryomodule that will accelerate the beams up to 10 MeV per nucleon for the heaviest isotopes available at ISOLDE. The first 2 cryomodules of the new linac, hosting each five superconducting cavities and one solenoid, were commissioned in August 2016. Besides demonstrating the experimental capabilities of the facility, this successful first run validated the technical choices of the HIE ISOLDE team and provided a fitting reward for eight years of rigorous R&D efforts. At the start of 2018, HIE-ISOLDE is expected to complete the energy upgrade, reaching 10 MeV/u and becoming an attractive facility for a wide variety of experiments. This contribution will focus on the results of the commissioning and on the main technical issues that were highlighted. * M.J.G. Borge and K. Riisager (2016), HIE-ISOLDE, the project and the physics opportunities, European Physical Journal A 52: 334, DOI: 10.1140/epja/i2016-16334-4
	Slides WEOAA2 [7.659 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEOAA2
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WEOBA2	Hollow Electron Beam Collimation for HL-LHC - Effects on the Beam Core	2482
	M. Fitterer, G. Stancari, A. Valishev Fermilab, Batavia, Illinois, USA R. Bruce, G. Papotti, S. Redaelli, D. Valuch, C. Xu CERN, Geneva, Switzerland G. Valentino University of Malta, Information and Communication Technology, Msida, Malta
	Funding: Fermilab is operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the US Department of Energy. Collimation with hollow electron beams is currently one of the most promising concepts for active halo control in the High Luminosity Large Hadron Collider (HL-LHC). To ensure the successful operation of the hollow beam collimator the unwanted effects on the beam core, which might arise from the operation with a pulsed electron beam, must be minimized. This paper gives a summary of the effect of hollow electron lenses on the beam core in terms of sources, provides estimates for HL-LHC and discusses the possible mitigation methods.
	Slides WEOBA2 [2.074 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEOBA2
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WEPIK030	Experimental Validation of the Achromatic Telescopic Squeezing Scheme at the LHC	2992
	S.D. Fartoukh, R. Bruce, F.S. Carlier, J.M. Coello de Portugal, A. Garcia-Tabares, E.H. Maclean, L. Malina, A. Mereghetti, D. Mirarchi, T. Persson, M. Pojer, L. Ponce, S. Redaelli, B. Salvachua, P.K. Skowroński, M. Solfaroli, R. Tomás, D. Valuch, A. Wegscheider, J. Wenninger CERN, Geneva, Switzerland
	The Achromatic Telescopic Squeezing (ATS) [1] scheme offers new techniques to deliver unprecedentedly small beam spot size at the interaction points of the ATLAS and CMS experiments of the LHC, while perfectly controlling the chromatic properties of the corresponding optics (linear and non-linear chromaticities, off-momentum beta-beating, spurious dispersion induced by the crossing bumps). The first series of beam tests with ATS optics were achieved during the LHC Run I (2011/2012) for a first validation of the basics of the scheme at small intensity. In 2016, a new generation of more performing ATS optics was developed and more extensively tested in the machine, still with probe beams for optics measurement and correction at β^=10 cm, but also with a few nominal bunches to establish first collisions at nominal β^ (40 cm) and beyond (33 cm), and to analysis the robustness of these optics in terms of collimation and machine protection. The paper will highlight the most relevant and conclusive results which were obtained during this second series of ATS tests. [1] S. Fartoukh , Phys. Rev. ST Accel. Beams 16, 111002
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK030
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Usage of the Transverse Damper Observation Box for High Sampling Rate Transverse Position Data in the LHC

389

L.R. Carver, X. Buffat, A.C. Butterworth, W. Höfle, G. Iadarola, G. Kotzian, K.S.B. Li, E. Métral, M. Ojeda Sandonís, M.E. Söderén, D. Valuch
CERN, Geneva, Switzerland

The transverse damper observation box (ADTObsBox) is a device that makes accessible the bunch-by-bunch turn-by-turn data recorded from the pickups of the LHC transverse damper. This device can provide online transient analysis of different beam dynamics effects (tunes and damping times at injection, for example), while also under development is an online coherent instability triggering system. This paper will provide an overview of the current setup and plans for future upgrades, as well as detailing how it deals with the large volume of data being generated. The results of some analysis that rely on the ADTObsBox will also be shown.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB113

Export •

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

MOPAB117

Online Bunch by Bunch Transverse Instability Detection in LHC

397

M.E. Söderén, G. Kotzian, M. Ojeda Sandonís, D. Valuch
CERN, Geneva, Switzerland

Reliable detection of developing transverse instabilities in the Large Hadron Collider is one of the main operational challenges of the LHC's high intensity proton run. A full machine snapshot provided from the moment of instability is a crucial input to develop and fine tune instability models. The transverse feedback system (ADT) is the only instrument in LHC, where a full rate bunch by bunch transverse position information is available. Together with a sub-micron resolution it makes it a perfect place to detect transverse beam motion. Very large amounts of data, at very high data rates (8 Gb/s) need to be processed on the fly to detect onset of transverse instability. A very powerful computer system (so called ADTObsBox) was developed and put into operation by the CERN RF group, which is capable of processing the full rate data streams from ADT and perform an on the fly instability detection. The output of this system is a timing event with a list of all bunches developing instability, which is then sent to the LHC-wide instability trigger network to freeze other observation instruments. The device also provides buffers with raw position data for offline analysis.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB117

Export •

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

TUPIK093

Sensitivity of the LHC Transverse Feedback System to Intra-Bunch Motion

1916

G. Kotzian, W. Höfle, D. Valuch
CERN, Geneva, Switzerland

The LHC Transverse Feedback System is designed to damp and counteract all possible coupled bunch modes between the lowest betatron frequency and 20 MHz. The present study reveals that the analogue frontend processing scheme based on down converting the pick-up signal at the LHC RF frequency to baseband considerably extends the detected bunch movements visible to the feedback system to beyond 1 GHz. We develop an analytical model of the signal processing chain to explore the impact of even-symmetric and odd-symmetric intra-bunch movements on the detected beam position as a function of the longitudinal bunch shape. A set of equations is derived suitable for numerical simulations, or as a complement in particle tracking codes to further refine the behaviour of the LHC transverse feedback system.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPIK093

Export •

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

TUPVA007

Impact of LHC and SPS Injection Kicker Rise Times on Lhc Filling Schemes and Luminosity Reach

2043

W. Bartmann, M.J. Barnes, J. Boyd, E. Carlier, A. Chmielinska, B. Goddard, G. Kotzian, C. Schwick, L.S. Stoel, D. Valuch, F.M. Velotti, V. Vlachodimitropoulos, C. Wiesner
CERN, Geneva, Switzerland

The 2016 LHC proton filling schemes generally used a spacing between injections of batches of bunches into SPS and LHC corresponding to the design report specification for the SPS and LHC injection kicker rise times, respectively. A reduction of the batch spacing can be directly used to increase luminosity without detrimental effects on beam stability, and with no increase in the number of events per crossing seen by the experiments. Measurements and simulations were performed in SPS and LHC to understand if a shorter injection kicker rise time and associated tighter batch spacing would lead to increased injection oscillations of the first and last bunches of a bunch train and eventually also a systematic growth of the transverse emittance. The results were used to define the minimum possible batch spacing for an acceptable emittance growth in LHC, with gains of reductions of about 10% possible in both machines. The results are discussed, including the potential improvement of the LHC luminosity for different filling schemes.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA007

Export •

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

TUPVA029

Observations of Emittance Growth in the Presence of External Noise in the LHC

2117

X. Buffat, C. Tambasco, D. Valuch
CERN, Geneva, Switzerland
J. Barranco García, T. Pieloni, C. Tambasco
EPFL, Lausanne, Switzerland

Dedicated experiments were perfomed in the LHC to study the impact of noise on colliding high brightness beams. The results are compared to theoretical models and multiparticle tracking simulations. The impacts on the LHC operation and the HL-LHC project are discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA029

Export •

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

WEOAA2

Status of Radioactive Ion Beam Post-Acceleration at CERN-ISOLDE

2466

Y. Kadi, W. Andreazza, J. Bauche, A. Behrens, A.P. Bernardes, J.A. Ferreira Somoza, F. Formenti, M.A. Fraser, M.J. Garcia Borge, N. Guillotin, K. Johnston, G. Kautzmann, Y. Leclercq, M. Martino, A. Miyazaki, R. Mompo, A. Papageorgiou Koufidou, O. Pirotte, J.A. Rodriguez, S. Sadovich, E. Siesling, M. Therasse, D. Valuch, W. Venturini Delsolaro
CERN, Geneva, Switzerland

Funding: We acknowledge funding from the Belgian Big Science program of the FWO (Research Foundation Flanders) and the Research Council K.U. Leuven.
The HIE-ISOLDE project* (High Intensity and Energy ISOLDE) reached an important milestone in September 2016 when the first physics run was carried out with radioactive beams at 6 MV/m. This is the first stage in the upgrade of the REX post-accelerator, whereby the energy of the radioactive ion beams was increased from 3 to 5.5 MeV per nucleon. The facility will ultimately be equipped with four high-beta cryomodule that will accelerate the beams up to 10 MeV per nucleon for the heaviest isotopes available at ISOLDE. The first 2 cryomodules of the new linac, hosting each five superconducting cavities and one solenoid, were commissioned in August 2016. Besides demonstrating the experimental capabilities of the facility, this successful first run validated the technical choices of the HIE ISOLDE team and provided a fitting reward for eight years of rigorous R&D efforts. At the start of 2018, HIE-ISOLDE is expected to complete the energy upgrade, reaching 10 MeV/u and becoming an attractive facility for a wide variety of experiments. This contribution will focus on the results of the commissioning and on the main technical issues that were highlighted.
* M.J.G. Borge and K. Riisager (2016), HIE-ISOLDE, the project and the physics opportunities, European Physical Journal A 52: 334, DOI: 10.1140/epja/i2016-16334-4

Slides WEOAA2 [7.659 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEOAA2

Export •

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

WEOBA2

Hollow Electron Beam Collimation for HL-LHC - Effects on the Beam Core

2482

M. Fitterer, G. Stancari, A. Valishev
Fermilab, Batavia, Illinois, USA
R. Bruce, G. Papotti, S. Redaelli, D. Valuch, C. Xu
CERN, Geneva, Switzerland
G. Valentino
University of Malta, Information and Communication Technology, Msida, Malta

Funding: Fermilab is operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the US Department of Energy.
Collimation with hollow electron beams is currently one of the most promising concepts for active halo control in the High Luminosity Large Hadron Collider (HL-LHC). To ensure the successful operation of the hollow beam collimator the unwanted effects on the beam core, which might arise from the operation with a pulsed electron beam, must be minimized. This paper gives a summary of the effect of hollow electron lenses on the beam core in terms of sources, provides estimates for HL-LHC and discusses the possible mitigation methods.

Slides WEOBA2 [2.074 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEOBA2

Export •

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

WEPIK030

Experimental Validation of the Achromatic Telescopic Squeezing Scheme at the LHC

2992

S.D. Fartoukh, R. Bruce, F.S. Carlier, J.M. Coello de Portugal, A. Garcia-Tabares, E.H. Maclean, L. Malina, A. Mereghetti, D. Mirarchi, T. Persson, M. Pojer, L. Ponce, S. Redaelli, B. Salvachua, P.K. Skowroński, M. Solfaroli, R. Tomás, D. Valuch, A. Wegscheider, J. Wenninger
CERN, Geneva, Switzerland

The Achromatic Telescopic Squeezing (ATS) [1] scheme offers new techniques to deliver unprecedentedly small beam spot size at the interaction points of the ATLAS and CMS experiments of the LHC, while perfectly controlling the chromatic properties of the corresponding optics (linear and non-linear chromaticities, off-momentum beta-beating, spurious dispersion induced by the crossing bumps). The first series of beam tests with ATS optics were achieved during the LHC Run I (2011/2012) for a first validation of the basics of the scheme at small intensity. In 2016, a new generation of more performing ATS optics was developed and more extensively tested in the machine, still with probe beams for optics measurement and correction at β^*=10 cm, but also with a few nominal bunches to establish first collisions at nominal β^* (40 cm) and beyond (33 cm), and to analysis the robustness of these optics in terms of collimation and machine protection. The paper will highlight the most relevant and conclusive results which were obtained during this second series of ATS tests.
[1] S. Fartoukh , Phys. Rev. ST Accel. Beams 16, 111002

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK030

Export •

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