IPAC2017 - List of Keywords (distributed)

Paper	Title	Other Keywords	Page
MOPAB009	Decomposition of Beam Losses at LHC	beam-losses, betatron, proton, collimation	88
	B. Salvachua, D. Mirarchi, M. Pojer, S. Redaelli, R. Rossi, G. Valentino, M. Wyszynski CERN, Geneva, Switzerland
	The LHC collimation system provides betatron cleaning and off-momentum cleaning in two different locations of the LHC ring. In the betatron cleaning area, three primary collimators cut the primary halo in horizontal, vertical and skew planes. The beam loss monitors located downstream each of these collimators can be used to diagnose the main plane of loss. We present here a method to identify these beam losses at the LHC and decompose them as a linear combination of loss scenarios using singular value decomposition to calculate Moore-Penrose pseudoinverse of the scenario matrix. This matrix has been used to evaluate the type of beam losses in different stages of the LHC cycle.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB009
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MOPIK096	Predictability of the Beam Quality During RFQ Voltage Tuning	emittance, rfq, simulation, quadrupole	748
	A. Ponton ESS, Lund, Sweden A.C. France CEA/IRFU, Gif-sur-Yvette, France
	It has previously been demonstrated that certain spatial harmonics of the dipolar and quadrupolar components of the RFQ voltage have stronger effects on the beam quality than others. The study suggested that, during the tuning process to compensate for manufacturing errors, some harmonic contents (other than the first ones) should be minimized. The analysis presented in this paper looks at how we can predict the beam quality knowing the content of each voltage harmonics. We propose also a strategy to minimize the impacts of the voltage errors on the output beam phase space during the tuning phase. A. Ponton, A.C. France, Y.I. Levinsen, O. Piquet, B. Pottin, and E. Sargsyan, Voltage Error Studies in the ESS RFQ, in Proc. 7th International Particle Accelerator Conference (IPAC'16), Busan, Korea, May 2016, paper THPMB039, pp. 3320-3323, ISBN: 978-3-95450-147-2
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK096
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MOPVA097	Finite Element Analysis on Helium Discharge from Superconducting RF in the Storage Ring Tunnel	simulation, cryogenics, SRF, cavity	1085
	J.-C. Chang, F. Z. Hsiao, J.C. Huang, S.P. Kao, H.C. Li, W.R. Liao, C.Y. Liu, H.H. Tsai, Z.-D. Tsai NSRRC, Hsinchu, Taiwan
	Liquid helium for transferring cooling power from the cryogenic plant to the magnets and SRF cavities had been widely applied on the advanced large superconducting particle accelerators. For requirements of high stable and reliable operation, many efforts have been put into the improvement and modification of the cryogenic system. However, personnel safety is another critical issue of the cryogenic system. Once large liquid helium was released on the atmospheric tunnel, the volume of helium will expand several hundred times and cause oxygen deficiency in short time due to sudden change of helium density. In this study, we applied numerical simulation to analyze helium discharge through a SRF cavity in the TPS tunnel.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA097
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TUPAB132	A Novel Dual-Mode Dual-Frequency Linac Design	impedance, operation, cavity, network	1634
	M.H. Nasr, S.G. Tantawi SLAC, Menlo Park, California, USA
	In this paper we will present a new type of accelerator structure that operates simultaneously at two accelerating modes with two frequencies. The frequencies are not harmonically related, but rather have a common sub-harmonic. This design will use a recently developed parallel-feeding network that feeds every cavity cell independently using a distributed feeding network. This will overcome many of the practical complications of coupled cell structure. We will provide the theoretical background for our dual-mode design as well as present our optimized design that operates at C and X bands simultaneously and provides enhanced gradient and efficiency compared to single-mode designs.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPAB132
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TUPIK045	Closed Orbit Feedback for FAIR - Prototype Tests at SIS18	controls, software, feedback, closed-orbit	1784
	B.R. Schlei, H. Liebermann, D. Ondreka, P.J. Spiller, R.J. Steinhagen GSI, Darmstadt, Germany
	A new steering software for cycle-to-cycle closed orbit as well as trajectory control is currently under development for FAIR's planned control system. It has been successfully tested with beam at the SIS18 in 2016. COAT (i.e., Controlling Orbits And Trajectories) has been realized as a distributed, Java-based application. It consists of a background daemon process that handles the actual beam-based feedback logic, and independent clients that provide visualization and various user-interaction capabilities. Built on top of the LSA settings management system, code-shared and also used at CERN, the system is kept generic. Furthermore, it is designed to support multiple accelerators, transfer lines and users in parallel. In particular, it can handle continuously changing optics and other in advance known changing beam parameters. The COAT computer program is part of a set of newly developed beam-based feedback tools* for FAIR. Preliminary results of our proof-of-concept prototype studies indicate, e.g., in view of the observed SIS18 machine reproducibility, that such a cycle-to-cycle feedback control scheme may be adequate also for the other FAIR accelerators and transfer lines. *see separate contribution by R. J. Steinhagen et al.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPIK045
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WEPAB018	Engineering Collaboration Experience at the European XFEL	project-management, database, monitoring, controls	2604
	L. Hagge, M. Hüning, J. Kreutzkamp DESY, Hamburg, Germany
	The construction of the European XFEL involved a huge internationally distributed and inter-disciplinary engineering effort. This paper discusses examples for good engineering practices which have been successfully developed and applied in the construction of the European XFEL. It addresses appropriate combination of de-/central activities in design collaboration and integration; the use of manufacturing bills of materials for coordinating and tracking contributions, as well as for clarifying responsibilities; the right amount of reviews for keeping activities in synch; some specific needs of and measures for in-kind collaboration; and general methods, tools and practices and spirit for efficient communication and collaboration.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPAB018
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WEPIK001	Advanced Beam Dump for FCC-ee	collider, simulation, electron, positron	2906
	A. Apyan ANSL, Yerevan, Armenia B. Goddard, F. Zimmermann CERN, Geneva, Switzerland K. Oide KEK, Ibaraki, Japan
	A modified beam dump for the future electron positron circular collider FCC-ee is discussed. The extraction line with a dilution kicker system distributes bunches at different transverse locations on the face of the beam dump. For a standard absorber the maximum energy deposition of all bunches occurs at the same longitudinal position inside the beam dump. This region experiences an enormous temperature rise compared with the surrounding parts of the beam dump. We propose a novel type of beam dump which spreads out the deposited energy over its whole volume quasi-uniformly, thereby reducing the maximum temperature rise. Results of Monte-Carlo simulations for a multi-material mosaic beam dump and for absorbers with distorted shapes are shown.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK001
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WEPVA146	Vacuum System Design and Simulation for CHESS-U	vacuum, dipole, operation, electron	3612
	Y. Li, S.T. Barrett, D.C. Burke, J.V. Conway, X. Liu, A. Lyndaker Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: This work is supported by National Science Foundation Reward #DMR-1332208 A major upgrade project (dubbed CHESS-U) is planned to elevate performance of Cornell High Energy Synchrotron Source (CHESS) to the state-of-art 3rd generation light sources. In the project, about 80-m of Cornell Electron Storage Ring (CESR) will be replaced with double-bend achromat (DBA) lattice to reduce electron beam emittance. In this presentation, we will describe designs of the CHESS-U vacuum system, including new beam pipe extrusions and chambers, sliding joints, and crotch absorbers. Vacuum pumping system consists of distributed pumps (in the form of NEG strips) in the dipole chambers, and compact discrete NEG/Ion pumps in the quad straight and undulator beampipes. MolFlow+ is used to evaluate pumping performances of the CHESS-U vacuum system. First, we demonstrate that the planned vacuum pumping system can achieve and sustain required ultra-high vacuum level in CHESS-U operations, after an initial beam conditioning. Second, we will explore beam commissioning processes of the new vacuum chambers, and simulate the saturation of the NEG strips during the commissioning. These simulations will aid continuing design optimization for the CHESS-U vacuum pumping system.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA146
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THPIK001	Copper Accelerating Structure Fabrication With Controled Cu-Ag Joining Conditions	vacuum, experiment, controls, data-analysis	4104
	V. Danielyan, V.S. Avagyan, S.G. Dekhtiarov, T.H. Mkrtchyan, S. Naghdalyan, A.S. Simonyan, V. V. Vardanyan CANDLE SRI, Yerevan, Armenia A.V. Tsakanian HZB, Berlin, Germany
	The paper is devoted to the development of technological processes of copper accelerating structures fabrication from oxygen-free copper. The experimental set-up for vacuum brazing of long accelerating structures with optimal Cu-Ag joining conditions is described. The experimental results of precise machining and subsequent vacuum brazing of Ag-Cu eutectic are presented
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPIK001
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THPIK101	Quarter Wavelength Combiner for an 8.5kW Solid-State Amplifier and Conceptual Study of Hybrid Combiners	operation, insertion, synchrotron, status	4324
	T.-C. Yu, F.Y. Chang, L.-H. Chang, M.H. Chang, L.J. Chen, F.-T. Chung, M.-C. Lin, Z.K. Liu, C.H. Lo, C.L. Tsai, Ch. Wang, M.-S. Yeh NSRRC, Hsinchu, Taiwan
	Experimental results to combine ten 900 W solid-state amplifier modules based on typical quarter wavelength 10-way combiners are described for a total of 8.5 kW RF power output at 500 MHz. The power gain and phase distribution among the ten modules are measured and calculated to sense the combination efficiency. The combination efficiency of 100 modules differing in power gain and phase distribution is theoretically analysed. Groups of 5, 10, 25, 50 and 100 units are used in 4, 3, 2, and 1-stage power combination for total 100 units and the characteristics are calculated and investigated, including bandwidth, efficiency and even redundancy under various output VSWR levels. To simplify combining complexity and to eliminate the drawbacks of single stage combiners, a multi-way 2-stage coaxial to waveguide combiner is thus proposed as an expandable power combiner.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPIK101
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THPVA064	Timing System at ESS	timing, EPICS, operation, proton	4588
	J. Cereijo García, T. Korhonen, J.H. Lee, D.P. Piso ESS, Lund, Sweden R.R. Osorio UDC, A Coruña, Spain
	The European Spallation Source (ESS) is a research facility being built in Lund (Sweden) that will produce neutrons by the spallation process. It uses the Micro-Research Finland (MRF) Timing System, which provides a complete event-based timing distribution system. The timing signal generation consists of a basic topology: an Event Generator (EVG), an optical distribution layer (fan-out modules) and an array of Event Receivers (EVRs). The timing system will provide clock synchronization and timing services to devices with real time requirements. Its main purposes are event generation and distribution, time stamping and synchronous data transmission. The event clock frequency will be 88.0525 MHz, divided down from the bunch frequency of 352.21 MHz. An integer number of ticks of this clock will define the beam macropulse full length, around 2.86 ms, with a repetition rate of 14 Hz. ESS will be the first facility to deploy large amounts of uTCA EVRs, and is planning to take advantage of the features provided by the uTCA standard, like trigger and clock distribution over the backplane. These EVRs are already being deployed in some systems and test stands.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPVA064
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Paper

Title

Other Keywords

Page

MOPAB009

Decomposition of Beam Losses at LHC

beam-losses, betatron, proton, collimation

88

B. Salvachua, D. Mirarchi, M. Pojer, S. Redaelli, R. Rossi, G. Valentino, M. Wyszynski
CERN, Geneva, Switzerland

The LHC collimation system provides betatron cleaning and off-momentum cleaning in two different locations of the LHC ring. In the betatron cleaning area, three primary collimators cut the primary halo in horizontal, vertical and skew planes. The beam loss monitors located downstream each of these collimators can be used to diagnose the main plane of loss. We present here a method to identify these beam losses at the LHC and decompose them as a linear combination of loss scenarios using singular value decomposition to calculate Moore-Penrose pseudoinverse of the scenario matrix. This matrix has been used to evaluate the type of beam losses in different stages of the LHC cycle.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB009

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

MOPIK096

Predictability of the Beam Quality During RFQ Voltage Tuning

emittance, rfq, simulation, quadrupole

748

A. Ponton
ESS, Lund, Sweden
A.C. France
CEA/IRFU, Gif-sur-Yvette, France

It has previously been demonstrated that certain spatial harmonics of the dipolar and quadrupolar components of the RFQ voltage have stronger effects on the beam quality than others*. The study suggested that, during the tuning process to compensate for manufacturing errors, some harmonic contents (other than the first ones) should be minimized. The analysis presented in this paper looks at how we can predict the beam quality knowing the content of each voltage harmonics. We propose also a strategy to minimize the impacts of the voltage errors on the output beam phase space during the tuning phase.
* A. Ponton, A.C. France, Y.I. Levinsen, O. Piquet, B. Pottin, and E. Sargsyan, Voltage Error Studies in the ESS RFQ, in Proc. 7th International Particle Accelerator Conference (IPAC'16), Busan, Korea, May 2016, paper THPMB039, pp. 3320-3323, ISBN: 978-3-95450-147-2

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK096

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MOPVA097

Finite Element Analysis on Helium Discharge from Superconducting RF in the Storage Ring Tunnel

simulation, cryogenics, SRF, cavity

1085

J.-C. Chang, F. Z. Hsiao, J.C. Huang, S.P. Kao, H.C. Li, W.R. Liao, C.Y. Liu, H.H. Tsai, Z.-D. Tsai
NSRRC, Hsinchu, Taiwan

Liquid helium for transferring cooling power from the cryogenic plant to the magnets and SRF cavities had been widely applied on the advanced large superconducting particle accelerators. For requirements of high stable and reliable operation, many efforts have been put into the improvement and modification of the cryogenic system. However, personnel safety is another critical issue of the cryogenic system. Once large liquid helium was released on the atmospheric tunnel, the volume of helium will expand several hundred times and cause oxygen deficiency in short time due to sudden change of helium density. In this study, we applied numerical simulation to analyze helium discharge through a SRF cavity in the TPS tunnel.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA097

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TUPAB132

A Novel Dual-Mode Dual-Frequency Linac Design

impedance, operation, cavity, network

1634

M.H. Nasr, S.G. Tantawi
SLAC, Menlo Park, California, USA

In this paper we will present a new type of accelerator structure that operates simultaneously at two accelerating modes with two frequencies. The frequencies are not harmonically related, but rather have a common sub-harmonic. This design will use a recently developed parallel-feeding network that feeds every cavity cell independently using a distributed feeding network. This will overcome many of the practical complications of coupled cell structure. We will provide the theoretical background for our dual-mode design as well as present our optimized design that operates at C and X bands simultaneously and provides enhanced gradient and efficiency compared to single-mode designs.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPAB132

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TUPIK045

Closed Orbit Feedback for FAIR - Prototype Tests at SIS18

controls, software, feedback, closed-orbit

1784

B.R. Schlei, H. Liebermann, D. Ondreka, P.J. Spiller, R.J. Steinhagen
GSI, Darmstadt, Germany

A new steering software for cycle-to-cycle closed orbit as well as trajectory control is currently under development for FAIR's planned control system. It has been successfully tested with beam at the SIS18 in 2016. COAT (i.e., Controlling Orbits And Trajectories) has been realized as a distributed, Java-based application. It consists of a background daemon process that handles the actual beam-based feedback logic, and independent clients that provide visualization and various user-interaction capabilities. Built on top of the LSA settings management system, code-shared and also used at CERN, the system is kept generic. Furthermore, it is designed to support multiple accelerators, transfer lines and users in parallel. In particular, it can handle continuously changing optics and other in advance known changing beam parameters. The COAT computer program is part of a set of newly developed beam-based feedback tools* for FAIR. Preliminary results of our proof-of-concept prototype studies indicate, e.g., in view of the observed SIS18 machine reproducibility, that such a cycle-to-cycle feedback control scheme may be adequate also for the other FAIR accelerators and transfer lines.
*see separate contribution by R. J. Steinhagen et al.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPIK045

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WEPAB018

Engineering Collaboration Experience at the European XFEL

project-management, database, monitoring, controls

2604

L. Hagge, M. Hüning, J. Kreutzkamp
DESY, Hamburg, Germany

The construction of the European XFEL involved a huge internationally distributed and inter-disciplinary engineering effort. This paper discusses examples for good engineering practices which have been successfully developed and applied in the construction of the European XFEL. It addresses appropriate combination of de-/central activities in design collaboration and integration; the use of manufacturing bills of materials for coordinating and tracking contributions, as well as for clarifying responsibilities; the right amount of reviews for keeping activities in synch; some specific needs of and measures for in-kind collaboration; and general methods, tools and practices and spirit for efficient communication and collaboration.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPAB018

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

WEPIK001

Advanced Beam Dump for FCC-ee

collider, simulation, electron, positron

2906

A. Apyan
ANSL, Yerevan, Armenia
B. Goddard, F. Zimmermann
CERN, Geneva, Switzerland
K. Oide
KEK, Ibaraki, Japan

A modified beam dump for the future electron positron circular collider FCC-ee is discussed. The extraction line with a dilution kicker system distributes bunches at different transverse locations on the face of the beam dump. For a standard absorber the maximum energy deposition of all bunches occurs at the same longitudinal position inside the beam dump. This region experiences an enormous temperature rise compared with the surrounding parts of the beam dump. We propose a novel type of beam dump which spreads out the deposited energy over its whole volume quasi-uniformly, thereby reducing the maximum temperature rise. Results of Monte-Carlo simulations for a multi-material mosaic beam dump and for absorbers with distorted shapes are shown.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK001

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

WEPVA146

Vacuum System Design and Simulation for CHESS-U

vacuum, dipole, operation, electron

3612

Y. Li, S.T. Barrett, D.C. Burke, J.V. Conway, X. Liu, A. Lyndaker
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: This work is supported by National Science Foundation Reward #DMR-1332208
A major upgrade project (dubbed CHESS-U) is planned to elevate performance of Cornell High Energy Synchrotron Source (CHESS) to the state-of-art 3rd generation light sources. In the project, about 80-m of Cornell Electron Storage Ring (CESR) will be replaced with double-bend achromat (DBA) lattice to reduce electron beam emittance. In this presentation, we will describe designs of the CHESS-U vacuum system, including new beam pipe extrusions and chambers, sliding joints, and crotch absorbers. Vacuum pumping system consists of distributed pumps (in the form of NEG strips) in the dipole chambers, and compact discrete NEG/Ion pumps in the quad straight and undulator beampipes. MolFlow+ is used to evaluate pumping performances of the CHESS-U vacuum system. First, we demonstrate that the planned vacuum pumping system can achieve and sustain required ultra-high vacuum level in CHESS-U operations, after an initial beam conditioning. Second, we will explore beam commissioning processes of the new vacuum chambers, and simulate the saturation of the NEG strips during the commissioning. These simulations will aid continuing design optimization for the CHESS-U vacuum pumping system.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA146

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THPIK001

Copper Accelerating Structure Fabrication With Controled Cu-Ag Joining Conditions

vacuum, experiment, controls, data-analysis

4104

V. Danielyan, V.S. Avagyan, S.G. Dekhtiarov, T.H. Mkrtchyan, S. Naghdalyan, A.S. Simonyan, V. V. Vardanyan
CANDLE SRI, Yerevan, Armenia
A.V. Tsakanian
HZB, Berlin, Germany

The paper is devoted to the development of technological processes of copper accelerating structures fabrication from oxygen-free copper. The experimental set-up for vacuum brazing of long accelerating structures with optimal Cu-Ag joining conditions is described. The experimental results of precise machining and subsequent vacuum brazing of Ag-Cu eutectic are presented

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPIK001

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

THPIK101

Quarter Wavelength Combiner for an 8.5kW Solid-State Amplifier and Conceptual Study of Hybrid Combiners

operation, insertion, synchrotron, status

4324

T.-C. Yu, F.Y. Chang, L.-H. Chang, M.H. Chang, L.J. Chen, F.-T. Chung, M.-C. Lin, Z.K. Liu, C.H. Lo, C.L. Tsai, Ch. Wang, M.-S. Yeh
NSRRC, Hsinchu, Taiwan

Experimental results to combine ten 900 W solid-state amplifier modules based on typical quarter wavelength 10-way combiners are described for a total of 8.5 kW RF power output at 500 MHz. The power gain and phase distribution among the ten modules are measured and calculated to sense the combination efficiency. The combination efficiency of 100 modules differing in power gain and phase distribution is theoretically analysed. Groups of 5, 10, 25, 50 and 100 units are used in 4, 3, 2, and 1-stage power combination for total 100 units and the characteristics are calculated and investigated, including bandwidth, efficiency and even redundancy under various output VSWR levels. To simplify combining complexity and to eliminate the drawbacks of single stage combiners, a multi-way 2-stage coaxial to waveguide combiner is thus proposed as an expandable power combiner.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPIK101

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THPVA064

Timing System at ESS

timing, EPICS, operation, proton

4588

J. Cereijo García, T. Korhonen, J.H. Lee, D.P. Piso
ESS, Lund, Sweden
R.R. Osorio
UDC, A Coruña, Spain

The European Spallation Source (ESS) is a research facility being built in Lund (Sweden) that will produce neutrons by the spallation process. It uses the Micro-Research Finland (MRF) Timing System, which provides a complete event-based timing distribution system. The timing signal generation consists of a basic topology: an Event Generator (EVG), an optical distribution layer (fan-out modules) and an array of Event Receivers (EVRs). The timing system will provide clock synchronization and timing services to devices with real time requirements. Its main purposes are event generation and distribution, time stamping and synchronous data transmission. The event clock frequency will be 88.0525 MHz, divided down from the bunch frequency of 352.21 MHz. An integer number of ticks of this clock will define the beam macropulse full length, around 2.86 ms, with a repetition rate of 14 Hz. ESS will be the first facility to deploy large amounts of uTCA EVRs, and is planning to take advantage of the features provided by the uTCA standard, like trigger and clock distribution over the backplane. These EVRs are already being deployed in some systems and test stands.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPVA064

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