Workshop on Beam-Induced Quenches

15 Sept 2014, 08:00 → 16 Sept 2014, 19:00 Europe/Zurich

30/7-018 - Kjell Johnsen Auditorium (CERN)

Anton Lechner (CERN), Belen Maria Salvachua Ferrando (CERN), Bernhard Auchmann (CERN), Mariusz Sapinski (CERN)

Overview:

During Run 1, beam-induced quenches have not yet been a limiting factor in the operation the LHC. After the long shutdown, the LHC will operate with much smaller operational margins, and at two thirds higher beam energy. Losses downstream of collimation, debris from the interaction regions, and, last not least, the occurrence of dust particles crossing the beams in arbitrary locations around the ring (colloquially called U.F.O.s, unidentified falling objects), will make beam-induced quenches a much more likely scenario during Run 2.

In view of this, controlled beam-loss experiments have been carried out before the long shutdown, in order to gather data that allows extrapolating to operation at 6.5 TeV. Detailed analysis of the events has been carried out throughout the long shut down. It has revealed strengths and weaknesses in our understanding of beam-loss events and beam-induced quenches. Based on this experience, we have launched the effort to update the settings of beam-loss monitors around the ring.

It is the aim of this workshop to survey the operational experience of superconducting accelerators and transfer lines, analyze the results and lessons learned of beam-loss experiments at the LHC, scrutinize the status of numerical models for the prediction of quench levels in superconducting accelerator magnets, and review the strategies for beam-loss monitoring in the LHC after the long shutdown. Moreover, we intend to stimulate a discussion on road-maps for the experimental validation of numerical and analytical models for quench- and damage levels for transient beam losses in accelerator magnets.

Organizers: B. Auchmann, A. Lechner, B. Salvachua, M. Sapinski
Proceedings Editor: E. Todesco
Administration: S. Sapountzi

summary 140619_BIQ_Workshop_preliminary_program_short.docx 140619_BIQ_Workshop_preliminary_program_short.pdf

Monday 15 September

Registration

Welcome Message

Convener: Dr Andrzej Siemko (CERN)

slides 140915_WelcomeMessage_BIQ2014.pdf 140915_WelcomeMessage_BIQ2014.pptx

Session 1: Operational Experience with Beam Losses and Beam-Induced Quenches

In this session the experience with beam-induced quenches in large superconducting accelerators and transfer lines is presented. Topics of interest include: beam loss mechanisms, statistics and analysis of beam-loss events, BLM systems parameters, threshold-setting strategies, and quench-level models as well as damage-level models for transient beam losses in SC magnets.

Conveners: Dr Andrzej Siemko (CERN), Dr Mariusz Sapinski (CERN)

1 Beam-Losses and Beam-Induced Quenches at J-PARC T2K Neutrino Beam-Line SC Magnet System

via video-link

Speaker: Kenichi Sasaki

Slides BIQWS14_ks.pdf

2 Beam Losses and beam induced quenches at the LHC

Speaker: Belen Maria Salvachua Ferrando (CERN)

02-Salvachua.docx

02-Salvachua.pdf

Slides BeamLossesLHC_belen.pdf

10:40 Coffee

3 Beam losses at Hera and Tevatron

with contributions from Kay Wittenburg (DESY) and Nikolai Mokhov (FNAL)

Speaker: Dr Mariusz Sapinski (CERN)

Slides 20140915_FNAL_DESY_BLosses.pdf 20140915_FNAL_DESY_BLosses.pptx

4 SIS100 - Estimations of Systematic and Spurious Beam Losses and Quench Protection

Speaker: Carsten Omet (GSI Helmholtzzentrum für Schwerionenforschung mbH)

5 Beam-Losses and Beam-Induced Quenches at BNL

Speaker: Mei Bai (Brookhaven National Laboratory)

Slides

• RHIC_BeamInducedMagnetQuench.pdf
• RHIC_BeamInducedMagnetQuench.pdf
• RHIC_BeamInducedMagnetQuench.pptx

13:00 Lunch Break

Session 2: Quench Tests at the LHC

This session is devoted to a series of controlled beam-loss experiments performed in the LHC during Run1. Loss durations ranged from single-turn losses to over 20-s loss duration. The experimental setup is introduced, followed by the main aspects of BIQ analysis: loss pattern estimation, particle shower simulations, and electro-thermal calculations. Analysis results and possible improvements for future experiments are discussed.

Conveners: Bernd Dehning (CERN), Dr Chiara Bracco (CERN)

6 Setup of LHC Quench Experiments

Speaker: Dr Mariusz Sapinski (CERN)

Slides 20140915_LHC_QuenchTests.pdf 20140915_LHC_QuenchTests.pptx

7 Particle Tracking for Orbit-Bump Quench Tests at LHC

Speaker: Vera Chetvertkova (CERN)

07-Chetvertkova.docx

07-Chetvertkova.pdf

Slides 25-Beam-Ind-Quenches-Workshop-15Sep14.pdf 25-Beam-Ind-Quenches-Workshop-15Sep14.pptx

8 Particle-Tracking for Collimation Studies

Speaker: Dr Roderik Bruce (CERN)

Paper BIQ2014_RB.docx BIQ2014_RB.pdf

Slides 2014.09.15--Quench_workshop--collimation_tracking.pdf 2014.09.15--Quench_workshop--collimation_tracking.pptx

15:30 Coffee

9 Particle shower simulations for LHC quench tests: methodology, challenges and selected results

Speaker: Anton Lechner (CERN)

Slides 2014_15_09_biq14partshowersim.pdf

10 Electro-thermal simulations of superconductors in case of beam losses

Speaker: Arjan Verweij (CERN)

Slides BIQ_Verweij_2014-09-15_(QP3).pdf BIQ_Verweij_2014-09-15_(QP3).ppt

11 Lessons Learnt from Quench Tests at the LHC

Speaker: Bernhard Auchmann (CERN)

Slides 140915_QT_Summary.pdf 140915_QT_Summary.pptx

19:30 Dinner

Tuesday 16 September

Session 3: Heat Transfer R&D

The aim of the session is to present the state of the art in the study of heat transport from superconducting cables to liquid helium. Numerical models will be discussed, as well as the latest results of experimental work. We aim for a lively discussion on future experimental work to validate numerical models in the highly-relevant millisecond-loss regime (UFO losses in the LHC). Moreover, we want to devote one slot to the conception of an experimental program towards validated damage-levels for fast beam-loss events in superconducting accelerator magnets.

Conveners: Bernardo Bordini (CERN), Dr Gerard Willering (CERN)

12 Steady-State Heat Transfer in the LHC Superconducting Coils: Status of Experiments and Modelling

Speaker: Pier Paolo Granieri (CERN)

Slides Granieri_BIQ_workshop_16-9-2014_v3.pdf Granieri_BIQ_workshop_16-9-2014_v3.pptx

13 Possibilities of Finite Element Modelling for a Better Understanding of Heat Transfer in Rutherford-Type Cables

The results obtained with Finite Element models help to better understand the heat transfer mechanism in complex structures, like Nb-Ti Rutherford type cables. With FE models, it is possible to implement the real geometry with different levels of precision, giving the possibility to take into consideration the properties on interfaces between copper, helium and kapton, as well as phase changes in helium and the strongly non-linear behavior of HeII.

Speaker: Erwin Roland Bielert (CERN)

Slides BIQ_BIELERT_20140916_COMSOL.pdf BIQ_BIELERT_20140916_COMSOL.pptx

14 Modeling heat transfer to helium in the stability analysis of Rutherford cables

The main experimental results on the transient heat transfer from solid surfaces to liquid helium are summarized. Models of these phenomena in stability analyses of superconducting wires and cables are presented. A focus on the quench analysis of Rutherford cables subjected to the external heat disturbance due to Beam Losses is presented, showing the impact on stability margin of the heat transfer towards interstitial helium and helium bath. The effects of the non-uniformity of the heat disturbance over the cable volume and of the heat and current redistribution between strands are shown by comparing models of increasing complexity.

Speaker: Marco Breschi (U)

Slides Cern_BIQ_Breschi.pdf

10:40 Coffee

15 Transient heat and mass transfer to superfluid helium Application to superconducting magnet cooling

Comprehending the cooling of superconducting magnets with superfluid helium requires the knowledge of heat and mass transfer in different size and time scales. Moreover, steady-state, transient and phase change must be considered in order to cover a wide spectrum of working conditions and thermal events to which these magnets are subjected. Focusing on the transient heat and mass transfer to superfluid helium for superconducting magnets cooling, we present a non-exhaustive review of experimental measurements and modellings in the ms to µs time scale. Heat transfer in different configurations (wire, channel, confined geometries…) will be covered as well as the surface heat transfer and the phase change. Some experimental and numerical studies directly related to the cooling of superconducting magnet in superfluid helium will be discussed in more details.

Speakers: Bertrand Baudouy (CEA Saclay), Bertrand Baudouy (IRFU)

Slides BIQ2014_Baudouy.pdf

16 Development of a Novel Method for Exploration of the Thermal Response of Superconducting Cables to Pulse Heat Loads in Superfluid Helium

Speaker: Tiemo Winkler (Twente Technical University (NL))

Slides BIQ2014-Winkler.pdf BIQ2014-Winkler.pptx

17 Stability measurements Rutherford type cables

Speaker: Dr Gerard Willering (CERN)

Slides 2014-09-16-BLM-Willering-.pdf 2014-09-16-BLM-Willering-.pptx

18 Identification of Damage-Levels of SC Magnets for transient beam losses: Strategy and Plans

Speaker: Dr Daniel Wollmann (CERN)

18-wollman.docx

18-wollman.pdf

Slides 20140816_DWollman_BIQWS_DamageLimits_Of_SC_Magnets_v1.pdf 20140816_DWollman_BIQWS_DamageLimits_Of_SC_Magnets_v1.pptx

13:00 Lunch Break

Session 4: LHC BLM Thresholds for Run 2

The aim of this session is to review the strategy for setting the LHC Beam Loss Monitors Thresholds after the long shutdown. The different involved teams will present a proposal for new BLM thresholds. This will cover losses from U.F.O.-type events, collimation-induced losses during proton and ion operation, losses at the triplets, and injection and dump losses.

Conveners: Dr Daniel Wollmann (CERN), Dr Roderik Bruce (CERN)

19 Introduction to the LHC BLM system

Speaker: Dr Eva Barbara Holzer (CERN)

Slides ebHolzer_BLM_v1.pptx

20 BLM thresholds for post-LS1 LHC operation: UFOs and orbit bumps in the arcs and straight sections

Speaker: Anton Lechner (CERN)

Slides 2014_16_09_biq14arcblmthr.pdf

15:00 Coffee

21 Collimator BLM threshold strategy

Speaker: Dr Stefano Redaelli (CERN)

21-redaelli.pdf

Slides SRedaelli_2014-09-16.pdf

22 Luminosity debris and Inner Triplet BLM

Speaker: Luigi Salvatore Esposito (CERN)

Slides 2014-09-16_BLM_IT.v3.pdf

Session 5: Summary

23 Sessions Summary

Speakers: Bernd Dehning (CERN), Dr Chiara Bracco (CERN), Dr Gerard Willering (CERN), Dr Mariusz Sapinski (CERN), Dr Roderik Bruce (CERN)

Slides

• 2014.09.16--BIQ_Session_4_summary.pdf
• 2014.09.16--BIQ_Session_4_summary.pptx
• 2014-09-16-Summary-morning-session-1.pdf
• 2014-09-16-Summary-morning-session-1.pptx
• BeamInducedWorkshop_Session2_BD.pdf
• BeamInducedWorkshop_Session2_BD.pptx
• Summary_of_1st_session.pdf
• Summary_of_1st_session.pptx

Session 6: Experimental Roadmaps - Informal Brainstorming Continued

For those keenly interested in continuing the discussion on experimental programs, we would like to provide a dinner date in CERN's restaurant 1.