In 2015 the LHC entered the first year of its second long Run, and the first collisions at 13 TeV CoM were delivered to the experiments on 3 June, after two months of beam commissioning. The rest of the year was characterized by a stepwise increase in the number of bunches that allowed reaching 2244 bunches/ring and a peak luminosity of ~5e33cm-2s-1, for a total of just above 4 fb-1...
With the restart at a record energy level, 2015 has been a challenging year for the LHC. An analysis of the performance through the investigation of each phase of the nominal cycle will be presented. The possibility and different scenarios to potentially increase efficiency will also be discussed.
No major machine protection incidents occurred during the 2015 run, but a number of critical issues can be identified and will be presented. Details of the intensity ramp-up and the handing of the safety critical Machine Development requests are given. A look ahead to 2016 is given and the potential critical issues will be highlighted.
The beam cleaning performance of the collimation system at 6.5 TeV and its evolution over the year will be presented. Collimation setup and validation procedures will be presented, including the gain from the embedded beam position monitors.
The LHC operation in 2015 for the RF and transverse damper system is presented. After a brief summary of the changes made during LS1 and recommissioning in the beginning of 2015, operational RF and transverse damper parameters as well as new diagnostics are detailed. Finally, an outlook of plans for the next year is given.
As far as beam-losses are concerned, UFOs and the ULO have been the most prominent threats to machine availability in Run-2 proton operation. For the time being, the fast advance of the conditioning effect and the orbit bump around the ULO appear to have saved the day. In this presentation we will give an overview of beam losses in the LHC with protons and ions, the...
The brief experience with 25 ns beam in the LHC at the end of Run 1 suggested that the electron cloud effects were set to pose important challenges to the machine operation during Run 2. In spite of four weeks of dedicated scrubbing run, the 2015 proton run of the LHC fully confirmed this expectation, with the electron cloud severely degrading the beam quality at the...
Beam induced RF heating of several LHC devices represented a significant limitation before LS1. A lot of effort was invested by equipment groups to mitigate these issues and add monitoring to be able to react early. This effort clearly paid off in 2015 and most limitations could be waived. Bunch length could even be allowed to decrease below 1 ns during long fills without...
With the LHC operation at 6.5 TeV and with 25 ns bunch spacing after LS1, the understanding and control of beam instabilities in 2015 has become at least as challenging as during Run 1 and a crucial point to be followed to guarantee a smooth intensity ramp up. As expected, electron cloud appeared to be the dominant instability driver during the early phases of Run 2...
The LHC 2016 run will be a high intensity 25 ns physics production run. During the 2015 commissioning run several issues for the SPS and SPS-to-LHC transfer became apparent which will need to be addressed in 2016 and the years to come. Some of these will only be fully mitigated with the LIU upgrade of the SPS. This talk will summarize the experience with 25 ns beams in...
After summarizing the post-LS1 beam instrumentation performance, the presentation will focus on the key challenges for beam diagnostic systems in 2016. This will first concentrate on instruments that are essential for beam commissioning and operation, such as the BPM and tune systems for high sensitivity orbit and tune measurements. An overview will then be given of the...
A short update will be given about the activities being performed in the 2016-16 YETS by ATLAS and CMS. Particular focus will be given to activities on the critical path, notably the repair of the ATLAS End Cap Toroid Bellows, the cleaning of the CMS magnet cryogenic system and the diagnosis and repair of the water leak in the CMS end-cap.
Numerous fault tracking concepts and requirements were defined by the LHC Availability Working Group (AWG) during the study of LHC Run 1 availability (2010-2012). During Long-Shutdown 1 (LS1), these requirements were converted into an Accelerator Fault Tracker (AFT) tool, by a BE/CO, BE/OP and TE/MPE initiative. This paper presents an overview of the AWG concepts and requirements for...
Increasing LHC availability is one of the key challenges for improving luminosity production in the next years and particularly in view of HL-LHC. Both hardware performance and beam-related effects have an impact on the achieved availability and are directly influenced by the LHC operating conditions (e.g. in terms of radiation levels, number of beam-induced quenches, etc.). A review of the...
The first part of the presentation summarizes the cryogenic performance and availability for 2015 and the expected performance for 2016 after completion of the YETS activities. The cryogenic configuration used in 2015, observed issues and proposed improvements will be detailed. The second part of the presentation will focus on cryogenic power studies (design, installed, available) in order...
The contribution will review the upgrades to the LHC quench detection system (QDS) performed during LS1 and discuss the QDS dependability during LHC operation in 2015. The QDS performance with respect to reliability, availability and maintainability will be presented and analysed, including issues specific to the ion run. An account of the consolidation measures already successfully...
From individual system tests and commissioning after LS1 up to operation with beam, the talk will start with a quick overview on the main phases that the LHC magnet circuits have experienced since the last Chamonix meeting. The main faults and events along the 2015 beam operation will be reported and classified according to system, frequency and impact to downtime. The systems and aspects...
The hardware performance of the LHC power converters during 2015 is presented. After a brief summary of the changes made during LS1, the performance of the power converters will be detailed by presenting the availability matrices of the different systems. The efficiency of the mitigations deployed during LS1 as well as the remaining observed failure modes are discussed. Finally, an outlook...
The most critical failure scenarios for LHC machine protection concern the injection and dump systems. In view of operation at higher energy and intensity and in light of the experience gained during Run 1, several upgrades were put in place to further enhance the reliability of these systems. Changes were applied both to the protection elements and the kickers (magnets,...
The talk discusses the input from the experiments that is relevant to define next year's program. It covers the target for integrated luminosity for 2016, for both p-p and Heavy Ion physics, and the requests for special runs (high beta*, VdM scans, high or low pile-up runs…). The impact of LHC parameters and conditions on the experiments is also discussed, including the effect of pile-up,...
The baseline machine parameters of the 2016 LHC proton run are presented, with focus on beta* and the collimation hierarchy. The proposed scenario is based on input from operational experience and MDs in 2015. The parameters and settings have been chosen in order to provide significantly higher luminosity than in 2015, while staying within the boundaries where the safety and smooth...
Over the years the LHC beams in the injectors have evolved and production schemes alternative to the baseline scheme have been developed and tested. The baseline is recalled and the beams from the alternative productions schemes that are available to the LHC in 2016 are discussed together with their performance reach.
The 2016 run will end with proton-lead collisions at either 4Z TeV, as in 2013, or 6.5Z TeV, still to be defined. This talk reviews the special features of operation with asymmetric collisions, and the lessons of the 2013 proton-nucleus run, as well as the 2015 lead-lead run. A new proton filling scheme to match the lead scheme will have to be prepared in 2016. This talk also reviews the...
MD results from 2015 have been fundamental in deciding the 2016 LHC parameters and to shed light in unexplored regimes of operation both for LHC and HL-LHC. 2016 emerges with 50% more MD time than 2015 and likely with an improved efficiency for machine studies. Possible MD requests for 2016 and Run II, along with priorities, are currently being discussed in the LSWG framework with a...
In 2015, extended beam studies, a general project Cost and Schedule Review and several dedicated LIU project reviews contributed to define a number of important aspects of the final LIU roadmap. This brief presentation will describe the current LIU baseline and the performance reach of the main upgrades.
Preliminary results of the 2015 latest studies to understand limitations in the PS injectors chain will be given, as well as the prospective for the upgrades being installed in YETS 2015-16, and the plans for studies to be performed in 2016.
In this paper we report the status of the LINAC4 beam commissioning and detail the strategy for the remaining commissioning steps. The H- source present performance, the intensity achieved and its impact on the LIU parameters will be discussed. The overall schedule with emphasis on the beam availability for the half-sector test will be presented.
We will give an overview of the most important LIU upgrade items for both Booster and PS machines and report on their status and the plans until completion of the project. The main achievements in 2015 will be highlighted and the next steps in 2016 outlined. On the beam physics side, we will report on the progress with the production of the 25ns LHC beam in both machines...
In 2015 several important decisions were taken to define the baseline upgrade path of the SPS for LIU, and solid technical progress was made in the different upgrade work-packages. In this presentation the progress of the upgrade activities is described, together with the accompanying theoretical and simulation advances where relevant. The reviews and decisions on the...
Major upgrades of the RF systems in the injector chain are required to reach the high beam intensity and quality for the High-Luminosity LHC. Finemet technology has been retained as the baseline for the future RF systems of the PSB. Since LS1 the PSB is operated with a fully digital beam control system, which allowed gaining important operational experience especially in...
The status of the transverse feedback systems of the LHC injector chain - LEIR, PSB, PS and SPS - is reviewed. This includes the LIU upgrades already implemented and commissioned as well as the planned outstanding LIU work. The review includes capabilities of damping electron cloud instabilities as well as other limitations, and the role the high bandwidth feedback...
- HL-LHC upgrades during LS2 (collimators, TDIS, cryogenics, coating of IP2 and IP8 triplet beam screens)
- Beta* reach and performance (optics, ATS, flat vs. round)
- Validation of the levelling scenarios driven by pile-up measurements (beta* levelling in IP1/5 and separation in IP2/8) with high brightness beams
- Expected limitations (aperture, heat loads...
- Time line and criteria for deciding between options (design; prototyping; construction; commissioning) so that they are ready by LS3? is it already too late for some options?
- Implications / coordination with LIU upgrades
- What kind of feedback upgrade do we need (bandwidth)
- (provisionally)
- The upgrade strategy for the LHC collimation system relies on various inputs from the LHC operation: loss rates, quench limits of magnet against beam losses, beam stability limit from collimator impedance, etc.
- The performance assessment based on the LHC Run I entails intrinsic uncertainties because of the differences in beam energy, bunch spacing and...
- Planning and interface with other integration activities -> time line
- Test program and goals
- (provisionally)
- Issue and how to tackle
- Carbon coating
- Laser patterning
- R&D and downselection process
- (Provisional)
- During Run 1 and in 2015 LHC operation has not been perturbed by vibrations and higher frequency (>1 Hz) ground motion. The effects of some large earthquakes was observed on the beam orbits, but no beam was lost or spoiled by such events.
- In the coming years two new sources of perturbations could possibly impact LHC operation: civil engineering for HL-LHC in...
- LHC Pb-Pb performance prospects and LIU projections compared to experiments' requests, updated in the light of the 2015 Pb-Pb run.
- Sharing options among the experiments including LHCb.
- Experience and fedback from ion MDs 2015
- Recommended running scenario and schedule.
The non-LHC experiments have planned significant maintenance and consolidation efforts. The presentation will review the most relevant activities and will focus on support needed during (E)YETS from the technical sector.
After a brief review of the Plan Tool implementation, the first feedback will be evaluated and the consistency with LIU will be reviewed as a pilot check.
16 days are allocated in March 2016 to prepare the machine for the beam. Around 7000 powering tests will have to be performed to re-commission the superconducting circuits. An extensive list of tests will have to be executed as well on the various systems affected by interventions during YETS. A preliminary planning for these tests will be shown.
