LHC Performance Workshop - Chamonix 2010
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Europe/Zurich
Chamonix
Chamonix
"Le Majestic"
Description
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The LHC Performance Workshop will take place from 25 until 29 January 2010
in
the Centre de Congrès Le Majestic, Chamonix, France.
Attendance is by invitation
only.
The workshop will focus on how to reach design energy and push the performance to and beyond nominal. Radiation to electronics, intervention strategies and underground safety will also be addressed.
| Steve Myers | Chairman |
| Roger Bailey | Deputy Chairman |
| Frank Zimmermann | Scientific Secretary |
| Christian Carli | Editor of the Proceedings |
| Tjitske Kehrer | Workshop Secretariat |
| Pierre Charrue | Desktop support |
Support
Participants
279
View full list
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Session 1 - Preconditions for Operating at 5 TeV in 2010more information
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1
Scope and results of hardware commissioning to 3.5 TeV and lessons learntAfter the incident of the 19th September the LHC has been initially re-commissioned to operate at 1.18TeV. Compared with the previous year, the 2009 commissioning campaign took much less time to prepare the machine for operation. This was mainly possible thanks to the reduced energy level and the increased working time. While the preparation of the machine for operation to 3.5 TeV will require “only” one further step in the commissioning of the main circuits, the 5 TeV energy commissioning will require more tests of the different circuits and a deep analysis of the obtained results. An overview of what has been achieved is presented with a particular attention to the encountered (solved and remaining) non-conformities.Speaker: Matteo Solfaroli
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2
Enhanced QPS – Commissioning and performance at 3.5TeV, outlook towards 5 TeVDuring the shutdown of the LHC in 2009 the protection system for superconducting elements in the LHC QPS has been submitted to a substantial upgrade. The newly introduced layers of the QPS allow the monitoring and protection of the electrical interconnections between superconducting magnets with very high precision and extend the capability of the system to the timely detection of so-called aperture symmetric quenches in the LHC main magnets. In addition the immunity of the QPS with respect to powering failures has been improved by feeding all quench heater based protection systems by now two fully redundant UPS. The presentation will recall the commissioning of these systems and describe the first experience during LHC operation. The overall dependability of the QPS system will be addressed including an overview of methods and tools for analysis, maintenance and diagnostics. Additional operational requirements for the exploitation of the QPS will be discussed. Finally the necessary steps to prepare the system for LHC operation at 5 TeV will be presented.Speaker: Reiner Denz
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3
Do the splices limit us to reach 5TeV. Plans for 2010 runThe talk will start by reviewing the landscape: the results of the warm copper stabilizer measurements, the results of the splice measurements at cold and the allowed space for these variables as a function of LHC energy. It emerges that the limiting factor for operating safely at higher energies is our knowledge of copper stabilizer resistances. The available methods at our disposal for addressing the limiting factors and operating at a higher energy will then be reviewed and estimates of the effort and risk involved will be presented. These methods range from a complete warm-up of some sectors to the so-called pulsing method that can qualify a circuit to a specific energy. A figure-of-merit can then be given to each method by balancing the effort of each method against the expected gain of operating the LHC at higher energies.Speaker: Michael Koratzinos
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4
Lessons learnt from beam commissioning and early beam operation of the Beam Loss Monitors (+ outlook to 5TeV)Results from the 2008 and 2009 operation of the LHC BLM system are presented with respect to the reliability and availability of the system. Have the design goals been attained? Where are known limitations? Can they be overcome? If so, how and by when? Among others, the precision of the beam abort threshold levels with respect to the magnet quench levels will be discussed. Threshold levels at different energies will be compared to the noise levels and the limits of the readout electronics. Are the thresholds at higher energies still safely above the noise levels? Can the thresholds be set high enough to accommodate for increased beam intensity? An extrapolation from the measured loss profiles (injection losses as well as betatron cleaning and momentum cleaning losses) towards the expected loss profiles at higher intensity and energy will be given. It will be verified whether they would stay below quench and damage levels (respectively the currently enforced abort thresholds).Speaker: Barbara Holzer
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10:05
coffee break
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5
How to safely reach higher energies and intensities? Settings and commissioning of Machine Protection Systems for 5TeV operation (BIC, SMP, LBDS, BPM, BCT, PIC …)The LHC Machine Protection System has been commissioned in November and December 2009 for low intensity and low energy beam operation. During this period interlocks were activated step by step and masking of channels was used regularly to improve the commissioning efficiency. As intensity and energy are increased this flexibility will be lost as the machine has to be protected at all times. It is therefore essential that all protection functionality must be commissioned at low intensity. Intensity and energy must be increased progressively, and every new step in energy or optics must be performed at low intensity. The steps that must be performed at the various stages will be outlined. The issues related to masking of interlock channels will be discussed.Speaker: Jorg Wenninger
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6
What else needs to be done to reach 5 TeV and beyond? Consolidation and commissioning of essential magnet powering systemsIn this contribution the engineering changes introduced after the September 19 incident will be revisited, in the light of a 5 TeV physics run, and beyond. Some of these measures needs consideration as they were adapted, or commissioned for the initial low energy run. Also, the non conformities that need to be closed in order to run at 5 TeV will be discussed along with an estimate of the needed time and resources. Voltages, current ramp rates, and accelerations, heat loads and superconductor margins at higher energies will be reviewed with regard to their impact and limitations on QPS, EE, PC, ELQA, cryogenics and all other systems. A sketch of the required consolidation work on these essential magnet system will be presented.Speaker: Walter Venturini
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7
HWC 2010 and beyond – R.Schmidt - 15 minFor the years to come, extensive re-commissioning of the superconducting circuits is expected. In order to reduce the time and resources required for the re-commissioning, ideas how to improve the efficiency are discussed. Some of the steps during the re-commissioning can be optimised, reducing the number of interfaces between different teams. The different software tools can be improved and partially combined, in order to better follow up the evolution of a circuit and to optimise the coordination between different teams. This includes ELQA at warm, cooldown, ELQA at cold, cable connections, power converter unblocking and finally powering tests. Personal safety is vital, and an iteration for rationalising the safety procedures is proposed. Another important aspect is the general organisation, including the definition of responsibility for the commissioning and the transition between shutdown, hardware commissioning and beam operation. The preparation for the next commissioning campaign should start soon, since it will take some time to implement upgraded tools.Speaker: Rudiger Schmidt
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1
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16:30
coffee break
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Session 2 – Magnets and splices consolidation shutdown 2010/2011
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8
Overview of all superconducting splices in the LHC machineWe will first draw the inventory of the superconducting splices in the LHC machine and classify them by their criticality. The main issues for each splice type will be reviewed with a special emphasis on corrector circuits based on the past experience and knowledge accumulated during hardware commissioning. Finally, we will discuss the issues still open and the plan of action for the next months.Speaker: Nuria Catalan
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9
Minimum requirements for 13 kA splicesI will first show the validation of the simulations, based on experimental data from three RQ joint samples, tested in FRESCA in the previous months, and containing different stabilizer defects. Then I will present updated plots for the simulated safe machine current versus joint defect size, both for the RB and RQ circuits, focusing on 7 TeV operation. Finally I will discuss if qualification of the splices by means of an electrical measurement at room temperature is sufficient to predict its performance at cold.Speaker: Arjan Verweij
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10
Status of splices in 13 kA circuitsIn this contribution we will review what it has been achieved in terms of quality for the 13KA splices during the reassembly of the sector 3-4 respect to the previous production. Issues and requirements that should guide the choices for future consolidation of these interconnects (including the insulation) will be addressed, providing a first view of the ongoing efforts to translate these technical requirements into a viable technical design. Available tests will be reviewed together with the ongoing analysis of the circuit and the comparisons with practices in other labs.Speaker: Paolo Fessia
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11
Status of splices in 6 kA circuitsThis paper gives a progress report on the work done and on-going in the frame of the task force on the LHC splices consolidation. First, an inventory of the superconducting 6 kA splices all around the LHC machine is given. Then one circuit is presented in detail (Q7L2). The method and results of superconducting splices resistance measurement are given. The so-called hand praying splices are detailed: electrical and mechanical specifications, procedure used and tests performed on samples. Preliminary information is given on a possible reinforcement of these splices.Speaker: Jean-Philippe Tock
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12
Scenarios for consolidations interventionA Task Force has been set up to prepare the necessary consolidation actions for 7 TeV operation, specifically for splices: the mandate, composition, roles, organization and working time frame are presented. Very preliminary considerations for consolidation scenarios are presented, considering workload, resources and durations.Speaker: Francesco BertinelliPaper
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13
Dipoles retraining for 7 TeVWe outline the present understanding of the retraining of the main dipoles in the LHC sector 5-6 during 2008 hardware commissioning. Even though part of the observed retraining can be explained through the test of individual magnets taken during the production, there is an additional unexplained detraining. 6.5 TeV seems clearly at hand with a very limited retraining. We present the best estimates of the training needed to reach the range 6.5-7 TeV, using different methods. We then analyse correlations between performance and production procedures and components: the present stage of analysis does not show any trace of correlations, but the analysis is not yet completed. There is also no indication of a correlation with the storage time. A program for performing additional test at SM18 on individual spare dipoles is discussed. We then analyse the training needed for the other LHC magnets to reach 7 TeV. Options for speeding up the training of the dipoles are discussed. We finally present a proposal for a miniworkshop where the experience of other accelerators based on superconducting magnets is discussed.Speaker: Ezio Todesco
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8
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20:30
Dinner in Hotel Les Aiglons
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Session 3 - Optimise Interventions and Recovery from Collateral Damages on Cold Sectors
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14
Can we optimise the cleanup process further?Following the sector 3-4 incident, about 5 km of beam vacuum system have been spoiled with soot, metallic and super insulation debris. During four months, several teams have intensively worked to recover the beam vacuum system. The presentation will address the successive sequences of this activity in terms of preparation, execution and control. Steps where time was lost and the possible optimisations will be presented. The obtained quality performance of the cleaning activity and possible qualification means will be showed.Speaker: Vincent BaglinPaper
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15
What is the MCI in case of a “beam driven” failure of a magnet enclosureCalculation hypothesis Short-term versus long-term pressure effects Arc and stand-alone magnets Worst case, uncertaintySpeaker: Rob Van Weelderen
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16
Means to limit the collateral damages in the beam vacuum chamberThe incident in the sector 3-4 has pointed out the need to limit whenever possible the propagation of the contamination by soot, MLI and other debris to an entire arc. Indeed, the subsequent endoscopic inspection and cleaning imply about 6 months of shutdown and requires opening the interconnections every 200 m. Following a brief review of the 3-4 incident, the impact of a similar incident at other locations in the LHC ring will be discussed together with the expected impact onto the upstream and downstream vacuum sectors. Expected pressure profiles will be presented. Some proposal to limit the induced overpressure and the propagation of dusts will be discussed. Their feasibility and drawbacks as well as the prerequisite and time required for their implementation will be discussed and compared to solutions implemented in other accelerators. The applicability to the recently defined MCI will be commented.Speaker: Miguel Jimenez
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09:45
coffee break
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17
What repair activity can be done today on a locally warmed-up sub-sector?Interventions to repair components inside LHC cryostats can only be performed with the system at room temperature. The architecture of the cryogenic and vacuum system permits local warm-up of the 2.8 km arc cryostat. The method, prerequisites, means, constraints, risks and time to locally warm-up a sub-sector are compared to a complete arc warm-up, including the steps to get back to 1.9 K powering. Configuration variants in each arc sector and sub-sector are considered and their impact on the local warm-up procedure. Typical repairs such as diode exchange, helium leak repair and splice consolidation will be presented, including the recent experience of local warm-up in sectors 8-1 and 2-3 to repair DFBA flexible hoses. The necessity and impact of beam vacuum venting during local warm-up will be explained and reviewed.Speaker: Paul Cruikshank
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18
Can we change a magnet without warming-up a full arc?What can be done today? Time required, risk to cryogenic lines and beam vacuum (back-streaming of gas) Can the cryogenic distribution be adapted to allow it? Safety, in particular during welding processes of lines What has to be retested after such an intervention?Speaker: Serge Claudet
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19
Decoupling of adjacent cryogenic sectorsThe LHC sectors are coupled two by two via interconnection boxes allowing cryoplant cooling redundancy and efficient stand-by or low-beam-intensity operation. The present LHC cryogenic sectorization allows to performed mechanical interventions on the magnet cold-mass circuit of a sector, like diode or interconnection splice repairs while the adjacent sector remain in nominal cryogenic operation. However this sectorization does not allow exchanging a magnet or a QRL service module in a sector while keeping the adjacent sector in nominal cryogenic operation and the cooling redundancy ability. This presentation will describe, based on different scenarios, hardware update proposals allowing a complete separation of the two adjacent sectors.Speaker: Gerard Ferlin
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14
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16:30
Coffee break
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Session 4 - Safety for Personnel Underground - He Evacuation
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20
Safety Taskforce follow-up in perspective with 2nd LHC physics run in 2011Following the accident in sector 3-4 of 19th September 2008, the related safety of personnel in the LHC underground areas was investigated and preventive and corrective measures recommended. All efforts have been deployed to fulfill the short term recommendations of the Task Force. Still, many of the solutions implemented are of temporary nature and valid only for the 1st LHC physics run in 2009/10. The presentation address the safety measures that still need to be implemented for the 2nd LHC physics run in 2011.Speaker: Ralf Trant
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21
Protection of underground areas and He release to surfaceThe presentation reviews the status of the separation of underground areas from the LHC tunnel and the present pressure release paths in case of a large He leak. We also discuss the shortfalls of the present situation and present the strategy for the upgrade/consolidation of the He release in case of a MCI.Speaker: Sylvain Weisz
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22
Safety organization and Safety status of the experimentsThe LHC experiments have reached very high levels in Safety to face all possible risks associated to the LHC Run Period. Following appropriate risks assessments, the required level 3 alarm safety systems have been implemented, the radioprotection strategy has been set up, the adequate general and specific safety trainings have been developed. The Experiments safety organization and structures have been reinforced with: SLIMOS in the control rooms, radioprotection experts and assistants, patrollers, safety officers. The Experiments SLIMOS desks in the control rooms are playing a key role in this safety organization: controlling all safety and infrastructure data, operating a strict control and coordination of all experimental areas access, activities and emergency situations. Finally, all safety measures and protections have been implemented to protect the caverns in case of reoccurence of an Helium release in the Tunnel areas.Speaker: Olga Beltramello
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23
Safety consolidation and improvements in the experimentsThe LHC experiments started successfully and safely in November 2009 together with the LHC machine. Significant improvements to the safety of the underground experimental areas have been implemented after the accident of the 19.09.08. Nevertheless, some safety improvements could not have been finalized and therefore compensatory measures are put in place for the 2009/10 LHC run. This presentation will focus on the consolidation efforts for safety to be done at latest during the next long shut down.Speaker: Christoph Schaefer
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24
Work and Safety Organisation during LHC Shut Down.Following the restructuration beginning of 2009 the EN department took over the territorial safety responsibility for the machines. However, the beam related safety is still handled by BE and the supervision of the LHC safety will switch from the beams department to the EN department during shut downs. This presentation gives an overview of the safety organisation that will be in place during an LHC shut down. It will also review a number of questions that still need to be addressed and must be settled for the next long shut down. A primordial element of safety is the ability to control and trace all interventions. For this the AET (Avis d’Execution de Travaux) is under development and its main aspects will be presented. The AET is an improved tracing procedure replacing the ADI from the hardware commissioning, and the AOC.Speaker: John Pedersen
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25
What can the Safety Coordination do for you?The objective of this year’s presentation is to analyze the progress we have all made over the last 12 months, looking at the safety procedures (AOC ,VIC, ADI) define our strong points and see how we can improve them. Identify the weak points and high light the problems. Build in safety from the conception stage of “ALL” project including the LHC, defining the rule and regulation ensure they exist, that they are clear and the same for “ALL”. Show how close team work between all actors and in particular the safety coordination and general coordination will help with the organization for future shut downs. Make available a data base for all relevant documentation (DIMRA, PPSPS, SAFETY FILES, etc). Pin point the areas that need to be improved, to enables the organization to move forward in such a way that, the CERN remains the center of excellence throughout the world in all domains.Speaker: John Etheridge
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26
How radiation will change your lifeEstimations of losses around the LHC ring for several energy and intensity scenarios for the 2009/2010 run are reviewed. The presentation describes the impact of RP consideration on consolidation work during the next long shut down on potentially highly irradiated items such as experimental beam pipes, TAS and TAN, low-b triplets, collimators and Roman Pots. Access conditions during a short stop, and work restrictions during such an access is also addressed. The RP requirements for the next beam periods, together with fire protection constraints on the LHC cooling & ventilation, are also presented: these cover confinement, DP between ventilation sectors, air and water contamination.Speaker: Doris Forkel-Wirth
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27
Modification of the LHC underground ventilation systemThis presentation reviews the requirements of the HVAC system concerning confinement, filtering and smoke extraction. Being able to release He following minor leaks adds another level of complexity beyond the normal functionalities of a ventilation system. Propositions for upgrades are discussed, with improved sectorisation to fulfill the RP requirements as intensity and energy increase, and to add more flexibility on access during powering tests.Speaker: Mauro Nonis
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20
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20:30
Dinner in Hotel Les Aiglons
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Session 5 - Access System and Radiation Monitors
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28
How did the LHC access system perform in 2009?As in 2008, the access system has been used in different configurations all along the 2009 year, following the machine status: shut-down (plus reparation), powering tests period and finally beam operation. The performances following the different evolutions introduced during the year and the issues, solved or still pending, will be reviewed during the presentation. The list of needed modifications for a more reliable and efficient use of the system for 2010 run will also be presented and in particular the effort for the material detection device (MAD). And finally, the current implementation of the software interlock between the access system and the power converters will be presented reviewed and discussed.Speaker: Laurette Ponce
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29
How should the access system be operated while LHC is not in beam operation?There are 2 periods where the beams in the LHC machine are stopped; the “Shutdown and Commissioning” period and the “Technical Stop”. This talk will define how these different periods should be organized (scheduling, coordination, safety, access... ), and explain how the access system will be operated for personnel safety.Speaker: Julie Coupard
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30
Is there a need for re-sectorization and/or additional interlocks?The presentation explains the objectives and justifications, as well as the drawbacks of the current LHC sectorisation and the LASS/LACS. The lessons learnt from the September-2008 incident impose more constraints. New constraints linked to safety as well as to exploitation are reviewed. How can the new requests be addressed? Should the sectorisation be revised ? Would that imply more sector doors, less sector doors, other sector doors? Do the new constraints impose more ventilation doors? Should the LASS/LACS address more risks? Should we include additional interlocks such as ventilation doors and power converters in the LASS? What would be the consequences of such additional interlocks?Speaker: Marc Tavlet
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09:50
Coffee Break
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31
Impact of safety related requirements and evolutions on LASS and LACSThis paper will address the issues concerning the potential implementation impact of the main types of recent requirements and evolutions, in the light of the return of experience of the operations in 2009. The types of requirements can be divided into three categories: technical improvements, design modification & scope increase, and finally operational & procedural improvement. The phasing in time and impact of such modifications during machine operation shall be discussed. Possibilities and current plans for evolutions and modifications shall be presented as well as the potential constraints for operation of the LHC accelerator and experiments.Speaker: Rui Nunes
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32
How to achieve satisfactory performances of the access system: stability, efficiency, operation, fluidity ?Heavy utilisation of the access system during LHC hardware commissioning has uncovered shortcomings in the performance of the system. While generally available to operation as required, response of the system has sometimes been below expectations of its users and operators. Reasons for these problems are both technical and procedural. Issues have been found in both hardware and software as well as in the system's response to external factors, such as network problems. Real-world usage of the access system has also not always reflected its original design. Possibilities for improvement exist: It should be possible to automate some of the administrative checks by the operators in the restricted mode. The access cycle may be streamlined, and new lighter-weight access modes for specific situations may be investigated. User interface improvements are possible to facilitate management of multiple access points at busy times. The exact actions to be taken will need to be evaluated between the access and operational teams. The most important issues affecting the performance of the system should be addressed first to ensure the best possible service to the users during the next shutdown.Speaker: Timo HakulinenPaper
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33
Arcon/Ramses: Current status and operational risksThe levels of ionising radiation around the LHC injector chain are monitored by the ARCON system (born with LEP), the ones around the LHC by the state of the art system RAMSES. The talk will present the consequences for beam operation in case of technical failures of the monitoring system(s), the strategy chosen to replace ARCON with RAMSES and the corresponding mile stones of the initial replacement project (RAMSES-2-light) which will only cover the LHC injector chain. The replacement of the remaining ARCON system, i.e. of all non-LHC facilities will present another, major project (RAMSES-2).Speaker: Doris Forkel-Wirth
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28
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16:30
Coffee break
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Session 6 - Radiation to Electronics
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Review of critical radiation areas for LHC Electronics and mitigation actions. Radiation monitoring and first resultsThis presentation aims for an update of the radiation levels in the critical LHC areas, both based on updated FLUKA simulations as well as on early measurements. Furthermore, a detailed analysis of the respective particle energy spectra is given and put in contrast to present and possible future radiation sensitivities. The radiation monitoring improvements as performed during the 2009 shutdown are illustrated and conclusions for the actual impact on LHC operation and the measured shielding effectiveness are presented wherever available. Based on this, the 2008/2009 applied mitigation actions will be preliminary evaluated together with additionally foreseen short- and medium term measures.Speaker: Markus Brugger
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35
Review of exposed equipment in the LHC: a global viewAn overview of equipment exposed to radiation in critical LHC areas is presented and the most critical systems are high-lighted with respect to system criticality and operational impact in case of failure, as well as to the expected estimated radiation sensitivity in the different LHC points. System criticality is analysed in terms of failure consequences, while for equipment sensitivity, assumptions have to be made since a large fraction of LHC electronics is based on industrial equipment for which no reliable data for radiation tolerance exists. For both aspects, an update is given where detailed system conclusions can be drawn, and a global prioritization based on CERN and outside experience is presented where this is not possible.Speaker: Thijs Wijnands
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36
LHC Power Converters, the proposed approachThe constraints of the power converters with respect to possible SEE induced failures are outlined and put in contrast with the expected radiation levels in the various LHC critical areas. Options of new developments and respective constraints are reviewed and limitations redesigning a full new system are underlined. 2009 and former radiation test results are summarized to conclude what can be done in the mid/long-term to improve the situation for the power-converters and where the inherent limitations are.Speaker: Yves Thurel
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37
Is the WorldFIP a reliable Rad-hard Fieldbus on long term?The WorldFIP fieldbus was chosen to cover communication needs of critical LHC systems needing determinism and radiation tolerance. WorldFIP slaves use the MicroFIP chip produced by Alstom along with the FielDrive transceiver and associated magnetics. After Alstom announced a progressive decline in support of WorldFIP technology, BE-CO decided to start a technology in-sourcing program in order to guarantee local support of this strategic technology during the lifetime of LHC. The first phase of this program consists in designing an FPGA-based alternative to MicroFIP, called NanoFIP. In addition, the last generation of MicroFIP chips was manufactured using a newer process with reduced feature sizes and there are serious concerns about its radiation tolerance. The NanoFIP development is therefore now considered a critical part in the global strategy of providing a radiation-tolerant solution to WorldFIP users. The talk will give a brief overview of the architecture of WorldFIP as presently deployed in the LHC, identify the critical devices in terms of radiation tolerance, and show how NanoFIP will provide a solution in the close future. The status of the NanoFIP project will be reported, as well as long-term plans for the overall WorldFIP technology insourcing in BE-CO.Speaker: Javier SerranoPaper
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38
Summary of the 2009 irradiation tests and perspectives for future tests and facilitiesNumerous radiation tests were performed during 2009, both directly at CERN in CNGS, as well as at various outside facilities. This presentation gives an overview of the test results by putting them in contrast to expected radiation levels in the exposed areas. By applying a best guess scaling of the expected development of the respective LHC radiation levels, failure rates can be estimated for both short- medium- and long-term LHC operation. Based on this, the most critical systems and mitigation options are investigated. Furthermore, future test requirements are compared to the availability and characteristic of existing test facilities.Speaker: Daniel Kramer
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39
Experience with the ATLAS radiation policy: can we say we are safe?This talk will review the Radiation constraints in ATLAS and the reasons that lead us to define of a “strict” policy. The main points of the adopted policy will be summarized in particular the evaluation of the local radiation environment, procurement strategy, test procedures, recommended radiation facilities, criteria for acceptance, design margins. The problem of efficiently enforcing the users to comply with the policy within the available resources will be outlined presenting some case studies representative of the ATLAS experience. At the end, we will try to answer the most important question: at what level can we say we are safe?Speaker: Philippe Farthouat
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40
Where are we with the Long-term plans and the CERN-wide radiation PolicyThe different options for the long term consolidation plan are presented, which should ensure that the risk of SEE in control electronics installed in the LHC is minimized. The plan will imply full (or partly) relocation of the installed electronics for some locations like US85 or UJ56 and UJ76, additional shielding in different areas where relocation is not convenient and may imply major civil engineering for Point 1 and Point 5. The possibility to avoid some of this heavy works by modifying the loss pattern or by redesigning some of the control systems to be radiation tolerant will be summarized for the major systems. Finally, the basic principles to be fixed in a CERN wide radiation policy at CERN will be proposed, with the aim of ensuring that we will never in the future be obliged again to consolidate further exposed underground installations.Speaker: Roberto Losito
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34
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20:30
Dinner in Restaurant La Calèche
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Session 7 - Future Upgrade scenarios for the Injector Complex
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41
What will PS2 + SPL provide for LHC?What will this upgrade bring for the LHC in terms of beam (intensity, structure, emittance and quality) ? Realistic construction schedule including timeline for commissioning of the complex until it can deliver at least the present ultimate beam. Reliability issues as well as the cost of construction and operation of the new complex should be addressed.Speaker: Michael Benedikt
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42
Keeping the present injector complex running with high reliability for 10-20 more yearsEven if SPL and PS2 go ahead, it is unlikely that they will deliver nominal LHC beams before the early 2020’s. This means that the existing LHC Injector chain, SPS, PS & PSB, with LINAC4 replacing LINAC2, will have to continue to run with high reliability for more than 10 more years. This talk will examine what additional actions would need to be taken to ensure that the same Injector chain will continue to run reliably for the next 20-25 years i.e. the lifetime of the LHC.Speaker: Simon BairdPaper
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43
Possible improvements to the existing pre-injector complex in the framework of continued consolidationThe situation of the present pre-injection complex will be discussed with particular emphasis on the performance limitations. Mitigation measures will be discussed assuming that substantial consolidation work can be devoted to such improvements. Possible scenarios for the implementation of these measures will be outlined, together with an analysis of the impact on the performance of the LHC machine.Speaker: Massimo Giovannozzi
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10:00
Coffee break
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44
Upgrade possibilities in the SPSThe LHC beam with characteristics close to nominal was obtained in the SPS already a few years ago. The main beam-quality limitation comes from the e-cloud effect which seems also to be responsible for high beam losses. During MD sessions in 2008 and 2009 the total intensity of the LHC beam was limited to three PS batches. Intensities above nominal have not yet been seen in the SPS and possible limitations can only be estimated from the scaling laws and machine studies. Future upgrades aimed at removal of the known bottlenecks in the SPS are presented. The consequences of operating with SPL and PS2 as pre-injectors are also considered.Speaker: Elena Shaposhnikova
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45
Other scenarios for a partial upgrade of the injector complexIs there an alternative path for a partial upgrade of the injector complex, for example an RCS or FFAG? What would injection at a higher intensity into the PS bring? Would such a solution bring significant advantages?Speaker: Christian Carli
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41
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16:30
Coffee break
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Session 8 - LHC Upgrade Plans for the first long Shutdown
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46
Overview of IR upgrade scope and challengesThe goal of the LHC IR Upgrade Phase-1 is to provide more flexibility for focusing of the LHC beams in the ATLAS and CMS high luminosity insertions and to enable reliable operation of the collider at a luminosity above the nominal 1034 cm-2s-1. This improvement is achieved by replacing the present low-b triplets and D1 separation dipoles in these two insertions with new magnets having a considerably larger aperture. The magnets are built using the mature technology of Nb-Ti superconductors cooled at 1.9 K. A brief status of the project is given, and the boundary conditions (technical, budgetary and planning) are reviewed.Speaker: Ranko Ostojic
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47
Injector complex upgradesSummary of the LINAC4 project planning (including eventual required upgrades in the injector complex – PSB and PS), summary of the commissioning plan and the expected performance level and challenges (including the injector complex – PSB and PS), presentation of a time line for the expected–planned performance levels (bunch intensity and brightness versus time).Speaker: Maurizio Vretenar
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48
Optics Challenges and Solutions for the LHC Insertions Upgrade Phase IThe goal of the LHC Insertions (IR) Upgrade Phase-I is to enable a reliable operation of the machine with a performance at least doubled with respect to its design luminosity. One key ingredient is ideally a reduction of b* down to 25 cm, using a new inner triplet (IT) with longer NbTi quadrupoles operating at a lower gradient (~120 T/m) and therefore offering a larger aperture (120 mm). Reducing b*, but also operating at a lower IT gradient (which further increases the size of the b-functions all over the long straight section), has however a certain number of drawbacks other than the obvious need of increasing the aperture of the new low-beta quadrupoles. Without modifying the current layout of the matching section (MS) and assuming that the arc sextupoles cannot safely operate above nominal current (550A), optics solutions with a b* of 30 cm are already at the edge of feasibility, both in terms of mechanical aperture in the MS and new IT (assuming 120 mm aperture), in terms of gradients for some MS and DS quadrupoles and in terms of chromatic correction. These limitations will be analyzed in detail, in particular concerning the chromatic correction of the new inner triplet which requires an overall modification of the current LHC optics. Concerning the high luminosity insertions proper, the layout of the new IT and corresponding injection and collision optics (with b*> 30 cm) will be studied both in terms of mechanical aperture, chromatic correction, squeeze-ability, dynamic aperture and beam-beam effects.Speaker: Stephane Fartoukh
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49
Hardware challenges and limitations for the IR upgradesThe design work of the MQXC quadrupole magnets for the inner triplets is constrained by the baseline planning for the LHC-PP project, its co-funding by the European Union (PF-7), the suppression of superconducting cable development (using existing stock of LHC dipole cable), and the in-house production of the series magnets (with tooling recovered from the LHC production lines). Nevertheless, some innovative features will be implemented: more porous cable insulation, a new collar structure allowing horizontal assembly with a hydraulic collaring press, tuning shims for the adjustment of field quality, a fishbone like structure for the ground-plane insulation, an improved quench-heater design and, possibly, a cartridge-like solution for the routing of busbars. On the other hand, the production will follow established procedures for the curing and assembly of coils in order to match the workflow established in the “large magnet facility”. The design process takes full advantage of the recently improved software tools, featuring quench simulation, 3D coil optimization, and ROXIE-CATIA interfacing for the making of drawings and the manufacturing of coil-end spacers. The talk will focus on the recent design work. The critical paths for the production and cold-testing of the model magnet and prototype will be identified.Speaker: Stephan Russenschuck
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Summary of the collimation upgrade plansPhase 2 collimator jaws, Cryo collimators and eventual required additional tertiary collimators and absorbers. Main milestones and deadlines for decision taking (e.g. what choice for the secondary collimators etc.). Strategy and time estimate for installation and commissioning of the new collimation system.Speaker: Ralph Assmann
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Integration issues in the tunnel and impact on general LHC systemsPlanning of the various installation work in consideration of the space requirements, radiation levels, existing and missing infrastructures, alignment and survey, coordination issues for upgrade (e.g. collimation upgrade versus IR upgrade and impact of LHC general consolidation work on the LHC upgrade projects. Options for implementing some of the upgrade work already before the extended shutdown in 2014-2015.Speaker: Sylvain Weisz
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46
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20:30
Dinner in Hotel Les Aiglons
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Session 9 - Additional LHC upgrade scenarios
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53
Parameter space beyond 10<sup>34</sup>The parameters available (intensities, betas, crossing angles), the relationship between them, the constraints and challenges for each parameter, the possible ranges that could be explored, and different optimization strategies.Speaker: Frank Zimmermann
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54
Implications of higher intensities in the LHCOne route to higher performance is to increase the number of bunches or the bunch intensities, or both. What are the implications for the hardware systems of the machine (RF, collimators, beam dump, injection, cryogenics, and magnets)?Speaker: Ralph Assmann
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Crab CavitiesWith lower betas or longer bunches, luminosity loss due to the crossing angle becomes important. Crab cavities could minimize the loss. What are the scenarios for a crab cavity implementation in the LHC, the expected performance gain, hardware implications, R&D plan, the open questions (noise, machine protection, impedance?), issues with space for crab cavities and the auxiliary equipment (e.g. klystrons) close to IP1/5 and in IR4, and a possible schedule.Speaker: Rama Calaga
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09:45
Coffee break
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56
Luminosity optimization and levelingHow can the effective LHC luminosity be optimized by complementary measures, like beam-beam compensation (long-range, head-on?) and luminosity leveling (various schemes)? Which are the merits and challenges of each measure? Are there lessons for the upgrade strategy?Speaker: Jean-Pierre Koutchouk
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What do the experiments want?With the above in mind, which is the preferred upgrade strategy of the LHC experiments? Which upgrades are planned by the experiments, and how do these constrain the LHC upgrade paths?Speaker: Marzio NessiPaper
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Comparison of integrated luminositiesWith the above in mind, and under certain assumptions of machine availability, and turnaround, what monthly integrated luminosities could we expect for various scenarios (e.g. with or without IR upgrade, with or without injector upgrade at various times)?Speaker: Mike Lamont
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53
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12:30
Lunch in Hotel Les Aiglons
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Summary Session
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Summary of the Chamonix 2010 WorkshopSpeaker: Steve Myers
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16:00
coffee break
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16:45
Departure of bus for CERN (Les Aiglons)
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