IPAC2014 - List of Authors (Zerlauth, M.)

Paper	Title	Page
MOOCB01	Beam-induced Quench Tests of LHC Magnets	52
	M. Sapinski, B. Auchmann, T. Bär, W. Bartmann, M. Bednarek, S. Bozyigit, C. Bracco, R. Bruce, F. Cerutti, V. Chetvertkova, K. Dahlerup-Petersen, B. Dehning, E. Effinger, J. Emery, A. Guerrero, E.B. Holzer, W. Höfle, A. Lechner, A. Priebe, S. Redaelli, B. Salvachua, R. Schmidt, N.V. Shetty, A.P. Siemko, E. Skordis, M. Solfaroli Camillocci, J. Steckert, J.A. Uythoven, D. Valuch, A.P. Verweij, J. Wenninger, D. Wollmann, M. Zerlauth, E.N. del Busto CERN, Geneva, Switzerland
	At the end of the LHC Run1 a 48-hour quench-test campaign took place to investigate the quench levels of superconducting magnets for loss durations from nanoseconds to tens of seconds. The longitudinal losses produced extended from one meter to hundreds of meters and the number of lost protons varied from 10⁸ to 10¹³. The results of these and other, previously conducted quench experiments, allow the quench levels of several types of LHC magnets under various loss conditions to be assessed. The quench levels are expected to limit LHC performance in the case of steady-state losses in the interaction regions and also in the case of fast losses initiated by dust particles all around the ring. It is therefore required to accurately adjust beam loss abort thresholds in order to maximize the operation time. A detailed discussion of these quench test results and a proposal for additional tests after the LHC restart is presented.
	Slides MOOCB01 [2.737 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOOCB01
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MOPRO043	Handling 1 MW Losses with the LHC Collimation System	174
	B. Salvachua, R. Bruce, F. Carra, M. Cauchi, E.B. Holzer, W. Höfle, D. Jacquet, L. Lari, D. Mirarchi, E. Nebot Del Busto, S. Redaelli, A. Rossi, M. Sapinski, R. Schmidt, G. Valentino, D. Valuch, J. Wenninger, D. Wollmann, M. Zerlauth CERN, Geneva, Switzerland M. Cauchi UoM, Msida, Malta L. Lari IFIC, Valencia, Spain
	Funding: Research supported by EU FP7 HiLumi LHC (Grant agree. 284404) The LHC superconducting magnets in the dispersion suppressor of IR7 are the most exposed to beam losses leaking from the betatron collimation system and represent the main limitation for the halo cleaning. In 2013, quench tests were performed at 4 TeV to improve the quench limit estimates, which determine the maximum allowed beam loss rate for a given collimation cleaning. The main goal of the collimation quench test was to try to quench the magnets by increasing losses at the collimators. Losses of up to 1 MW over a few seconds were generated by blowing up the beam, achieving total losses of about 5.8 MJ. These controlled losses exceeded by a factor 2 the collimation design value, and the magnets did not quench.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO043
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MOPME046	Supervision Software for the Integration of the Beam Interlock System with the CERN Accelerator Complex	476
	M. Audrain, D. Anderson, M. Dragu, K. Fuchsberger, J.C. Garnier, A.A. Gorzawski, M. Koza, K.H. Krol, A. Moscatelli, B. Puccio, K. Stamos, M. Zerlauth CERN, Geneva, Switzerland
	The Accelerator complex at the European Organisation for Nuclear Research (CERN) is composed of many systems which are required to function in a valid state to ensure safe beam operation. One key component of machine protection, the Beam Interlock System (BIS), was designed to interface critical systems around the accelerator chain, provide fast and reliable transmission of beam dump requests and trigger beam extraction in case of malfunctioning of equipment systems or beam losses. Numerous upgrades of accelerator and controls components during the Long Shutdown 1 (LS1) are followed by subsequent software updates that need to be thoroughly validated before the restart of beam operation in 2015. In parallel, the ongoing deployments of the BIS hardware in the PS booster (PSB) and the future LINAC4 give rise to new requirements for the related controls and monitoring software due to their fast cycle times. This paper describes the current status and ongoing work as well as the long-term vision for the integration of the Beam Interlock System software into the operational environment.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME046
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MOPME050	Reliable Software Development for Machine Protection Systems	489
	J.C. Garnier, D. Anderson, M. Audrain, M. Dragu, K. Fuchsberger, A.A. Gorzawski, M. Koza, K.H. Krol, K. Misiowiec, K. Stamos, M. Zerlauth CERN, Geneva, Switzerland
	The Controls software for the Large Hadron Collider (LHC) at CERN, with more than 150 millions lines of code, resides amongst the largest known code bases in the world. Industry has been applying agile software engineering techniques for decades now, and the advantages of these techniques can no longer be ignored to manage the code base for large projects within the accelerator community. Furthermore, CERN is a particular environment due to the high personnel turnover and manpower limitations, where applying agile processes can improve both, the codebase management as well as its quality. This paper presents the successful application of the agile software development process SCRUM for machine protection systems at CERN, the quality standards and infrastructure introduced together with the agile process as well as the challenges encountered to adapt it to CERN’s environment.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME050
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TUPRO015	Update on Predictions for Yearly Integrated Luminosity for HL-LHC based on Expected Machine Availability	1036
	A. Apollonio, M. Jonker, R. Schmidt, B. Todd, D. Wollmann, M. Zerlauth CERN, Geneva, Switzerland
	Machine availability is one of the key performance indicators to reach the ambitious goals for integrated luminosity in the post Long Shutdown 1 (LS1) era. Machine availability is even more important for the future High Luminosity LHC (HL-LHC) [1]. In this paper a Monte Carlo approach has been used to predict integrated luminosity as a function of LHC machine availability. The baseline model assumptions such as fault-time distributions and machine failure rate (number of fills with stable beams dumped after a failure / total number of fills with stable beams) were deduced from the observations during LHC operation in 2012. The predictions focus on operation after LS1 and its evolution towards HL-LHC. The extrapolation of relevant parameters impacting on machine availability is outlined and their corresponding impact on fault time distributions is discussed. Results for possible future operational scenarios are presented. Finally, a sensitivity analysis with relevant model parameters like fault time and machine failure rate is discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO015
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TUPRO016	Machine Protection Challenges for HL-LHC	1039
	R. Schmidt, T. Bär, J. Wenninger, D. Wollmann, M. Zerlauth CERN, Geneva, Switzerland
	LHC operation requires the flawless functioning of the machine protection systems. The energy stored in the beam was progressively increased beyond the 140 MJ range at the end of 2012 at 4 TeV/c. The further increase to 364 MJ expected for 2015 at 6.5 TeV/c should be possible with the existing protection systems. For HL-LHC, additional failure modes are considered. The stored beam energy will increase by another factor of two with respect to nominal and a factor of five more than experienced so far. The maximum beta function will increase. It is planned to install crab cavities in the LHC. With crab cavities, sudden voltage decays within 100 us after e.g. cavity quenches lead to large beam oscillations. Tracking simulations predict trajectory distortions of up to 1.5 σ in the first turn after a sudden drop of the deflecting voltage in a single cavity within 3 turns. The energy of several MJ stored in halo protons that could hit the collimator in case of such events is far above damage level, even if the collimator jaws are made of robust material. In this paper we discuss the challenges for machine protection in the HL-LHC era and possible mitigation strategies.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO016
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THPRI020	Availability Studies for Linac4 and Machine Protection Requirements for Linac4 Commissioning	3807
	A. Apollonio, S. Gabourin, C. Martin, B. Mikulec, B. Puccio, J.L. Sanchez Alvarez, D. Wollmann, M. Zerlauth CERN, Geneva, Switzerland
	Linac4 is one of the key elements in the upgrade program of the LHC injector complex at CERN, assuring beams with higher bunch intensities and smaller emittance for the LHC and many other physics experiments on the CERN site. Due to the demand of continuous operation, the expected availability of Linac4 needs to be carefully studied already during its design phase. In this paper an overview of the relevant systems impacting on Linac4 machine availability is given: the various system failure modes are outlined as well as their impact on the total yearly machine downtime. Machine Protection Systems (MPS) play a significant role in reducing the risk associated to each failure mode and are therefore important for reaching the target availability. The Linac4 MPS requirements, with particular focus on the different commissioning phases, are discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI020
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THPRI021	Implementation of a Direct Link between the LHC Beam Interlock System and the LHC Beam Dumping System Re-triggering Lines	3810
	S. Gabourin, E. Carlier, R. Denz, N. Magnin, J.A. Uythoven, D. Wollmann, M. Zerlauth CERN, Geneva, Switzerland M. Bartholdt, B. Bertsche, V. Vatansever, P. Zeiler Universität Stuttgart, Stuttgart, Germany
	To avoid damage of accelerator equipment due to impacting beam, the controlled removal of the LHC beams from the collider rings towards the dump blocks must be guaranteed at all times. When a beam dump is demanded, the Beam Interlock System communicates this request to the Trigger Synchronisation and Distribution System of the LHC Beam Dumping System. Both systems were built according to high reliability standards. To further reduce the risk of incapability to dump the beams in case of correlated failures in the Trigger Synchronisation and Distribution System, a new direct link from the Beam Interlock System to the re-triggering lines of the LHC Beam Dumping System will be implemented for the start-up with beam in 2015. The link represents a diverse redundancy to the current implementation, which should neither significantly increase the risk for so-called asynchronous beam dumps nor compromise machine availability. This paper describes the implementation choices of this link. Furthermore the results of a reliability analysis to quantify its impact on LHC machine availability are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI021
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THPRI093	CSCM: EXPERIMENTAL AND SIMULATION RESULTS	3988
	S. Rowan, B. Auchmann, K. Brodzinski, Z. Charifoulline, R. Denz, V. Roger, I. Romera, R. Schmidt, A.P. Siemko, J. Steckert, H. Thiesen, A.P. Verweij, G.P. Willering, D. Wollmann, M. Zerlauth CERN, Geneva, Switzerland H. Pfeffer Fermilab, Batavia, Illinois, USA
	The copper-stabilizer continuity measurement - or CSCM - was devised to obtain a direct and complete qualification of the continuity in the 13 kA bypass circuits of the LHC, especially in the copper-stabilizer of the busbar joints and the bolted connections in the diode-leads. The circuit under test is brought to ~20 K, a voltage is applied to open the diodes, and the low-inductance circuit is powered with a pre-defined series of current profiles. The profiles are designed to successively increase the thermal load on the busbar joints up to a level that corresponds to worst-case operating conditions at nominal energy. In this way, the circuit is tested for thermal runaways in the joints - the very process that could prove catastrophic if it occurred under nominal conditions with the full circuit energy. Surveillance software and a numerical model were devised to carry out the analysis and ensure complete protection of the circuit from over-heating. A type test of the CSCM was successfully carried out in April 2013 on one main dipole and one main quadrupole circuit of the LHC. This paper describes the analysis procedure, the numerical model, and results of this first type test.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI093
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THPRI095	Testing Quality and Metrics for the LHC Magnet Powering System throughout Past and Future Commissioning	3995
	D. Anderson, M. Audrain, Z. Charifoulline, M. Dragu, K. Fuchsberger, J.C. Garnier, A.A. Gorzawski, M. Koza, K.H. Krol, S. Rowan, K. Stamos, M. Zerlauth CERN, Geneva, Switzerland
	The LHC magnet powering system is comprised of thousands of individual components to assure a safe operation when operating with stored energies as high as 10GJ in the superconducting LHC magnets. Each of these components has to be thoroughly commissioned following interventions and machine shutdown periods to assure their protection function in case of powering failures. As well as a dependable tracking of test executions it is vital that the executed commissioning steps and applied analysis criteria adequately represent the operational state of each component. The Accelerator Testing (AccTesting) framework in combination with a domain specific analysis language provides the means to quantify and improve the quality of analysis for future campaigns. Dedicated tools were developed to analyse in detail the reasons for failures and success of commissioning steps in past campaigns and to compare the results with newly developed quality metrics. Observed shortcomings and discrepancies are used to propose additional verification and mitigation for future campaigns in an effort to improve the testing quality and hence assure the overall dependability of subsequent operational periods.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI095
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THPRI097	A Retrospective View to the Magnet Interlock Systems at CERN	4001
	I. Romera, P. Dahlen, R. Mompo, B. Puccio, M. Zerlauth CERN, Geneva, Switzerland
	Several thousands of both, superconducting and normal conducting magnets are in charge of guiding the particle beams in CERN’s accelerator complex. In order to protect the magnet and powering equipment from damage, dedicated magnet interlock and protection systems are deployed throughout the various accelerators and transfer lines. These systems have worked extremely well during the first years of LHC operation, providing highly dependable interlocking of magnet powering based on industrial COTS components. This paper reviews the performance of the more than 70 individual installations during the first LHC running period and compares the operational experience with the initial expectations of dependability. Additional improvements required to address specific operational needs and observed shortcomings are presented. Finally, we review the existing magnet interlock infrastructure in the LHC injector complex and the ongoing renovation works during the first long shutdown.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI097
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Paper

Title

Page

Beam-induced Quench Tests of LHC Magnets

52

M. Sapinski, B. Auchmann, T. Bär, W. Bartmann, M. Bednarek, S. Bozyigit, C. Bracco, R. Bruce, F. Cerutti, V. Chetvertkova, K. Dahlerup-Petersen, B. Dehning, E. Effinger, J. Emery, A. Guerrero, E.B. Holzer, W. Höfle, A. Lechner, A. Priebe, S. Redaelli, B. Salvachua, R. Schmidt, N.V. Shetty, A.P. Siemko, E. Skordis, M. Solfaroli Camillocci, J. Steckert, J.A. Uythoven, D. Valuch, A.P. Verweij, J. Wenninger, D. Wollmann, M. Zerlauth, E.N. del Busto
CERN, Geneva, Switzerland

At the end of the LHC Run1 a 48-hour quench-test campaign took place to investigate the quench levels of superconducting magnets for loss durations from nanoseconds to tens of seconds. The longitudinal losses produced extended from one meter to hundreds of meters and the number of lost protons varied from 10⁸ to 10¹³. The results of these and other, previously conducted quench experiments, allow the quench levels of several types of LHC magnets under various loss conditions to be assessed. The quench levels are expected to limit LHC performance in the case of steady-state losses in the interaction regions and also in the case of fast losses initiated by dust particles all around the ring. It is therefore required to accurately adjust beam loss abort thresholds in order to maximize the operation time. A detailed discussion of these quench test results and a proposal for additional tests after the LHC restart is presented.

Slides MOOCB01 [2.737 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOOCB01

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MOPRO043

Handling 1 MW Losses with the LHC Collimation System

174

B. Salvachua, R. Bruce, F. Carra, M. Cauchi, E.B. Holzer, W. Höfle, D. Jacquet, L. Lari, D. Mirarchi, E. Nebot Del Busto, S. Redaelli, A. Rossi, M. Sapinski, R. Schmidt, G. Valentino, D. Valuch, J. Wenninger, D. Wollmann, M. Zerlauth
CERN, Geneva, Switzerland
M. Cauchi
UoM, Msida, Malta
L. Lari
IFIC, Valencia, Spain

Funding: Research supported by EU FP7 HiLumi LHC (Grant agree. 284404)
The LHC superconducting magnets in the dispersion suppressor of IR7 are the most exposed to beam losses leaking from the betatron collimation system and represent the main limitation for the halo cleaning. In 2013, quench tests were performed at 4 TeV to improve the quench limit estimates, which determine the maximum allowed beam loss rate for a given collimation cleaning. The main goal of the collimation quench test was to try to quench the magnets by increasing losses at the collimators. Losses of up to 1 MW over a few seconds were generated by blowing up the beam, achieving total losses of about 5.8 MJ. These controlled losses exceeded by a factor 2 the collimation design value, and the magnets did not quench.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO043

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MOPME046

Supervision Software for the Integration of the Beam Interlock System with the CERN Accelerator Complex

476

M. Audrain, D. Anderson, M. Dragu, K. Fuchsberger, J.C. Garnier, A.A. Gorzawski, M. Koza, K.H. Krol, A. Moscatelli, B. Puccio, K. Stamos, M. Zerlauth
CERN, Geneva, Switzerland

The Accelerator complex at the European Organisation for Nuclear Research (CERN) is composed of many systems which are required to function in a valid state to ensure safe beam operation. One key component of machine protection, the Beam Interlock System (BIS), was designed to interface critical systems around the accelerator chain, provide fast and reliable transmission of beam dump requests and trigger beam extraction in case of malfunctioning of equipment systems or beam losses. Numerous upgrades of accelerator and controls components during the Long Shutdown 1 (LS1) are followed by subsequent software updates that need to be thoroughly validated before the restart of beam operation in 2015. In parallel, the ongoing deployments of the BIS hardware in the PS booster (PSB) and the future LINAC4 give rise to new requirements for the related controls and monitoring software due to their fast cycle times. This paper describes the current status and ongoing work as well as the long-term vision for the integration of the Beam Interlock System software into the operational environment.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME046

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MOPME050

Reliable Software Development for Machine Protection Systems

489

J.C. Garnier, D. Anderson, M. Audrain, M. Dragu, K. Fuchsberger, A.A. Gorzawski, M. Koza, K.H. Krol, K. Misiowiec, K. Stamos, M. Zerlauth
CERN, Geneva, Switzerland

The Controls software for the Large Hadron Collider (LHC) at CERN, with more than 150 millions lines of code, resides amongst the largest known code bases in the world. Industry has been applying agile software engineering techniques for decades now, and the advantages of these techniques can no longer be ignored to manage the code base for large projects within the accelerator community. Furthermore, CERN is a particular environment due to the high personnel turnover and manpower limitations, where applying agile processes can improve both, the codebase management as well as its quality. This paper presents the successful application of the agile software development process SCRUM for machine protection systems at CERN, the quality standards and infrastructure introduced together with the agile process as well as the challenges encountered to adapt it to CERN’s environment.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME050

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TUPRO015

Update on Predictions for Yearly Integrated Luminosity for HL-LHC based on Expected Machine Availability

1036

A. Apollonio, M. Jonker, R. Schmidt, B. Todd, D. Wollmann, M. Zerlauth
CERN, Geneva, Switzerland

Machine availability is one of the key performance indicators to reach the ambitious goals for integrated luminosity in the post Long Shutdown 1 (LS1) era. Machine availability is even more important for the future High Luminosity LHC (HL-LHC) [1]. In this paper a Monte Carlo approach has been used to predict integrated luminosity as a function of LHC machine availability. The baseline model assumptions such as fault-time distributions and machine failure rate (number of fills with stable beams dumped after a failure / total number of fills with stable beams) were deduced from the observations during LHC operation in 2012. The predictions focus on operation after LS1 and its evolution towards HL-LHC. The extrapolation of relevant parameters impacting on machine availability is outlined and their corresponding impact on fault time distributions is discussed. Results for possible future operational scenarios are presented. Finally, a sensitivity analysis with relevant model parameters like fault time and machine failure rate is discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO015

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TUPRO016

Machine Protection Challenges for HL-LHC

1039

R. Schmidt, T. Bär, J. Wenninger, D. Wollmann, M. Zerlauth
CERN, Geneva, Switzerland

LHC operation requires the flawless functioning of the machine protection systems. The energy stored in the beam was progressively increased beyond the 140 MJ range at the end of 2012 at 4 TeV/c. The further increase to 364 MJ expected for 2015 at 6.5 TeV/c should be possible with the existing protection systems. For HL-LHC, additional failure modes are considered. The stored beam energy will increase by another factor of two with respect to nominal and a factor of five more than experienced so far. The maximum beta function will increase. It is planned to install crab cavities in the LHC. With crab cavities, sudden voltage decays within 100 us after e.g. cavity quenches lead to large beam oscillations. Tracking simulations predict trajectory distortions of up to 1.5 σ in the first turn after a sudden drop of the deflecting voltage in a single cavity within 3 turns. The energy of several MJ stored in halo protons that could hit the collimator in case of such events is far above damage level, even if the collimator jaws are made of robust material. In this paper we discuss the challenges for machine protection in the HL-LHC era and possible mitigation strategies.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO016

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THPRI020

Availability Studies for Linac4 and Machine Protection Requirements for Linac4 Commissioning

3807

A. Apollonio, S. Gabourin, C. Martin, B. Mikulec, B. Puccio, J.L. Sanchez Alvarez, D. Wollmann, M. Zerlauth
CERN, Geneva, Switzerland

Linac4 is one of the key elements in the upgrade program of the LHC injector complex at CERN, assuring beams with higher bunch intensities and smaller emittance for the LHC and many other physics experiments on the CERN site. Due to the demand of continuous operation, the expected availability of Linac4 needs to be carefully studied already during its design phase. In this paper an overview of the relevant systems impacting on Linac4 machine availability is given: the various system failure modes are outlined as well as their impact on the total yearly machine downtime. Machine Protection Systems (MPS) play a significant role in reducing the risk associated to each failure mode and are therefore important for reaching the target availability. The Linac4 MPS requirements, with particular focus on the different commissioning phases, are discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI020

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THPRI021

Implementation of a Direct Link between the LHC Beam Interlock System and the LHC Beam Dumping System Re-triggering Lines

3810

S. Gabourin, E. Carlier, R. Denz, N. Magnin, J.A. Uythoven, D. Wollmann, M. Zerlauth
CERN, Geneva, Switzerland
M. Bartholdt, B. Bertsche, V. Vatansever, P. Zeiler
Universität Stuttgart, Stuttgart, Germany

To avoid damage of accelerator equipment due to impacting beam, the controlled removal of the LHC beams from the collider rings towards the dump blocks must be guaranteed at all times. When a beam dump is demanded, the Beam Interlock System communicates this request to the Trigger Synchronisation and Distribution System of the LHC Beam Dumping System. Both systems were built according to high reliability standards. To further reduce the risk of incapability to dump the beams in case of correlated failures in the Trigger Synchronisation and Distribution System, a new direct link from the Beam Interlock System to the re-triggering lines of the LHC Beam Dumping System will be implemented for the start-up with beam in 2015. The link represents a diverse redundancy to the current implementation, which should neither significantly increase the risk for so-called asynchronous beam dumps nor compromise machine availability. This paper describes the implementation choices of this link. Furthermore the results of a reliability analysis to quantify its impact on LHC machine availability are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI021

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THPRI093

CSCM: EXPERIMENTAL AND SIMULATION RESULTS

3988

S. Rowan, B. Auchmann, K. Brodzinski, Z. Charifoulline, R. Denz, V. Roger, I. Romera, R. Schmidt, A.P. Siemko, J. Steckert, H. Thiesen, A.P. Verweij, G.P. Willering, D. Wollmann, M. Zerlauth
CERN, Geneva, Switzerland
H. Pfeffer
Fermilab, Batavia, Illinois, USA

The copper-stabilizer continuity measurement - or CSCM - was devised to obtain a direct and complete qualification of the continuity in the 13 kA bypass circuits of the LHC, especially in the copper-stabilizer of the busbar joints and the bolted connections in the diode-leads. The circuit under test is brought to ~20 K, a voltage is applied to open the diodes, and the low-inductance circuit is powered with a pre-defined series of current profiles. The profiles are designed to successively increase the thermal load on the busbar joints up to a level that corresponds to worst-case operating conditions at nominal energy. In this way, the circuit is tested for thermal runaways in the joints - the very process that could prove catastrophic if it occurred under nominal conditions with the full circuit energy. Surveillance software and a numerical model were devised to carry out the analysis and ensure complete protection of the circuit from over-heating. A type test of the CSCM was successfully carried out in April 2013 on one main dipole and one main quadrupole circuit of the LHC. This paper describes the analysis procedure, the numerical model, and results of this first type test.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI093

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THPRI095

Testing Quality and Metrics for the LHC Magnet Powering System throughout Past and Future Commissioning

3995

D. Anderson, M. Audrain, Z. Charifoulline, M. Dragu, K. Fuchsberger, J.C. Garnier, A.A. Gorzawski, M. Koza, K.H. Krol, S. Rowan, K. Stamos, M. Zerlauth
CERN, Geneva, Switzerland

The LHC magnet powering system is comprised of thousands of individual components to assure a safe operation when operating with stored energies as high as 10GJ in the superconducting LHC magnets. Each of these components has to be thoroughly commissioned following interventions and machine shutdown periods to assure their protection function in case of powering failures. As well as a dependable tracking of test executions it is vital that the executed commissioning steps and applied analysis criteria adequately represent the operational state of each component. The Accelerator Testing (AccTesting) framework in combination with a domain specific analysis language provides the means to quantify and improve the quality of analysis for future campaigns. Dedicated tools were developed to analyse in detail the reasons for failures and success of commissioning steps in past campaigns and to compare the results with newly developed quality metrics. Observed shortcomings and discrepancies are used to propose additional verification and mitigation for future campaigns in an effort to improve the testing quality and hence assure the overall dependability of subsequent operational periods.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI095

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THPRI097

A Retrospective View to the Magnet Interlock Systems at CERN

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I. Romera, P. Dahlen, R. Mompo, B. Puccio, M. Zerlauth
CERN, Geneva, Switzerland

Several thousands of both, superconducting and normal conducting magnets are in charge of guiding the particle beams in CERN’s accelerator complex. In order to protect the magnet and powering equipment from damage, dedicated magnet interlock and protection systems are deployed throughout the various accelerators and transfer lines. These systems have worked extremely well during the first years of LHC operation, providing highly dependable interlocking of magnet powering based on industrial COTS components. This paper reviews the performance of the more than 70 individual installations during the first LHC running period and compares the operational experience with the initial expectations of dependability. Additional improvements required to address specific operational needs and observed shortcomings are presented. Finally, we review the existing magnet interlock infrastructure in the LHC injector complex and the ongoing renovation works during the first long shutdown.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI097

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