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LHC Upgrades

LHC Upgrades. PPAP 14th July 2009 Steve Myers. 1. Peak Luminosity. N b number of particles per bunch n b number of bunches f r revolution frequency  n normalised emittance  * beta value at Ip F reduction factor due to crossing angle N b ,  n injector chain  * LHC insertion

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LHC Upgrades

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  1. LHC Upgrades PPAP 14th July 2009 Steve Myers 1

  2. Peak Luminosity Nbnumber of particles per bunch nbnumber of bunches frrevolution frequency nnormalised emittance *beta value at Ip F reduction factor due to crossing angle Nb, ninjector chain *LHC insertion F beam separation schemes nbelectron cloud effect

  3. LHC Upgrade-Phase I Goal of “Phase I” upgrade: Enable focusing of the beams to b*=0.25 m in IP1 and IP5, and reliable operation of the LHC at double the operating luminosity on the horizon of the physics run in 2014. Scope of “Phase I” upgrade: Upgrade of ATLAS and CMS experimental insertions. The interfaces between the LHC and the experiments remain unchanged at  19 m. Replace the present triplets with wide aperture quadrupoles based on the LHC dipole cables (Nb-Ti) cooled at 1.9 K. Upgrade the D1 separation dipole, TAS and collimation system so as to be compatible with the inner triplet aperture..

  4. Present limitations • 1. Lack of reliability: • Ageing accelerators (PS is 50 years old !) operating far beyond initial parameters • need for new accelerators designed for the needs of SLHC • 2. Main performance limitation: • Excessive incoherent space charge • tune spreads DQSC at injection in the • PSB (50 MeV) and PS (1.4 GeV) because • of the high required beam brightness N/e*. • need to increase the injection energy in the synchrotrons • Increase injection energy in the PSB from 50 to 160 MeV kinetic • Increase injection energy in the SPS from 25 to 50 GeV kinetic • Design the PS successor (PS2) with an acceptable space charge effect for the maximum beam envisaged for SLHC: => injection energy of 4 GeV

  5. Upgrade components Proton flux / Beam power Linac4 Linac2 50 MeV 160 MeV LPSPL PSB 1.4 GeV 4 GeV LPSPL: Low PowerSuperconducting Proton Linac (4 GeV) PS2: High Energy PS (~ 5 to 50 GeV – 0.3 Hz) SPS+: Superconducting SPS (50 to1000 GeV) SLHC: “Superluminosity” LHC (up to 1035 cm-2s-1) DLHC: “Double energy” LHC (1 to ~14 TeV) PS 26 GeV PS2 50 GeV Output energy SPS SPS+ 450 GeV 1 TeV LHC / SLHC DLHC 7 TeV ~ 14 TeV

  6. Layout of the new injectors SPS PS2 SPL PS Linac4

  7. Approved: Linac4 Direct benefits of the new linac Stop of Linac2: End of recurrent problems with Linac2 (vacuum leaks, etc.) End of use of obsolete RF triodes (hard to get + expensive) Higher performance: Space charge decreased by a factor of 2 in the PSB => potential to double the beam brightness and fill the PS with the LHC beam in a single pulse, => easier handling of high intensity. Potential to double the intensity per pulse. Low loss injection process (Charge exchange instead of betatron stacking) High flexibility for painting in the transverse and longitudinal planes (high speed chopper at 3 MeV in Linac4) First step towards the SPL: Linac4 will provide beam for commissioning LPSPL + PS2 without disturbing physics. Benefits for users of the PSB Good match between space charge limits at injection in the PSB and PS => for LHC, no more long flat bottom at PS injection + shorter flat bottom at SPS injection: easier/ more reliable operation / potential for ultimate beam from the PS More intensity per pulse available for PSB beam users (ISOLDE) – up to 2´ More PSB cycles available for other uses than LHC

  8. To be Approved 2012: LPSPL + PS2 Direct benefits of the LPSPL + PS2 Stop of PSB and PS: End of recurrent problems (damaged magnets in the PS, etc.) End of maintenance of equipment with multiple layers of modifications End of operation of old accelerators at their maximum capability Safer operation at higher proton flux (adequate shielding and collimation) Higher performance: Capability to deliver the ultimate beam for LHC to the SPS => potential to prepare the SPS for supplying the beam required for the SLHC, Higher injection energy in the SPS + higher intensity and brightness => easier handling of high intensity. Potential to increase the intensity per pulse. First step towards the SPL: Linac4 will provide beam for commissioning LPSPL + PS2 without disturbing physics. Benefits for users of the LPSPL and PS2 More than 50 % of the LPSPL pulses will be available (not needed by PS2) => New nuclear physics experiments – extension of ISOLDE (if no EURISOL)… Upgraded characteristics of the PS2 beam wrt the PS (energy and flux) Potential for a higher proton flux from the SPS

  9. Not yet considered for approval: Stage 2 SPL Upgrade the LPSPL into an SPL (multi- MW beam power at 2-5 GeV): 50 Hz rate with upgraded infrastructure (electricity, water, cryo-plants, …) 40 mA beam current by doubling the number of klystrons in the superconducting part) Possible users EURISOL (2nd generation ISOL-type RIB facility) => special deflection system(s) out of the SPL into a transfer line => new experimental facility with capability to receive 5 MW beam power => potential of supplying b-unstable isotopes to a b-beam facility… Neutrino factory => energy upgrade to 5 GeV (+70 m of sc accelerating structures) => 2 fixed energy rings for protons (accumulator & compressor) => accelerator complex with target, m capture-cooling-acceleration (20-50 GeV) and storage

  10. Potential collaborations between UK institutes and CERN for the PS2 Design

  11. Potential collaboration CERN - CI • Representatives of the Cockcroft Institute have expressed interest to look into the possibilities to collaborate with CERN on PS2 magnets. • In August 2008, CERN and CI signed an Agreement concerning the collaboration in accelerator physics and technologies. • Agreement includes CI contributing to the design of magnets for PS2 and SPL (high power RF and beam dynamics + collimation) with ~2 FTEs/year effort. • As follow-up, a discussion has been held between M. Benedikt, E. Tsesmelis and G. de Rijk of CERN and J. Dainton of the CI. • “an opportunity to initiate a collaboration in which the CI takes responsibility for magnet design for PS2 with a view to completion of the PS2 CDR by 2011 for a decision in 2012, which itself may lead to a bid for funding a substantial contribution to the build of PS2 by the CI with UK in close consultation with the science, engineering and knowledge exchange initiatives in STFC”. • On a medium term (3 to 6 months) two CI collaborators with magnet experience or interest could come to CERN if a funding scheme can be found: • Note the RF system for the SPL has many other possible similar uses (ESS, HIE-ISOLDE, EURISOL ...) This could be a great opportunity for technology transfer to UK industry. • CI and CERN management could now take further steps towards a closer collaboration.

  12. Potential collaboration CERN - CI • Conceptual design and prototyping of a magnet type e.g. main quadrupoles • One or more CI persons could come for a certain period to CERN to work together with the PS2 team on the specifications. • The detailed design work could then be done at CI. • Construction of a prototype could be done at CI and/or UK firms. • Acceptance tests can be partly done at CI and finished at CERN. • The work could be considered as an in-kind contribution to the PS2, other scenarios are still open. • This effort has the full support of the CI Director, S. Chattopadhyay

  13. Potential collaboration CERN–JAI on PS2 laser stripping R&D • The John Adams Institute is interested in collaborating with CERN on R&D for a laser stripping system for PS2 H- injection. (CERN group EN/STI) • First informal discussions have been held between B.Goddard (CERN) and G.Blair (JAI), on possible topics and deliverables. • Promising areas for collaboration have been identified as: • Studies of potential high power laser systems; • Investigation (and prototyping?) of build-up cavities for the interaction region; • Quantum mechanical studies of resonant excitation and photo-dissociation in magnetic fields; • Calculations of expected ionization efficiencies for different schemes. • JAI already have laser experts and will investigate whether the required atomic physics expertise can be found in-house. • The PS2 studies could be complimentary to a short-term hardware project for the Linac4 laser wire, which JAI is also interested in. (CERN group EN/STI) • Collaboration details need to be decided – a promising option is a PhD student combined with the contributions from other experts. • There are wider international issues and other interested partners could include STFC/RAL and SNS, and possible other US labs.

  14. Linac4 – Laser Emittance Measurement • Linac4 is a normal-conducting H− linear accelerator at 160 MeV energy, presently under construction, which will inject into the PS Booster and at a later stage into the Superconducting Proton Linac (SPL). • Linac commissioning is foreseen in 2013 and connection to PS Booster at beginning of 2014. • A prototype Laser-based Emittance Measurement at the end of the linac would simplify commissioning, complementing the information from the conventional emittance measurement at PSB entrance. Space charge forbids using standard profile-based emittance measurements at the exit of the linac. • Laser Emittance Measurements are presently studied in the UK (RHUL) and have potential applications in many projects (ESS, ILC,…). Transfer line to PSB 160 MeV 100 MeV Position of a Laser-based Emittance Measurement 50 MeV Similar technology could be used for laser stripping of the H- for the PS2 (no foil, less losses)

  15. Inner Triplets • The Present participation from the UK in the LHC IR Upgrade – Phase1 includes design work on the multipole correctors for the new inner triplets. This work is done by STFC/RAL within the SLHC-PP FP7 contract. The effort was dimensioned according to the available funds from this contract and is relatively small (design of a skew quadrupole magnet) • There is clearly potential to increase the STFC/RAL participation on this topic, • Strengthen significantly the design team and increase the scope of RAL involvement to other multipole correctors. [Note that the SLHC-PP effort was initially insufficient, and that its effectiveness has been reduced in 2009 due to redeployment of the RAL engineer to other projects]. • Production of multipole correctors in UK industry under RAL supervision. The estimated cost of the multipole correctors is of the order of 1.5 MCHF. • If approved by STFC, the extension of the UK participation could be negotiated immediately. The design work should be completed by mid-2010, and production is planned for 2011-12.

  16. Thank you for your attention 17

  17. Topics LHC Shutdown work General Status New Quench protection system Splice Measurements At superconducting temperatures At non-superconducting temperatures Powering Tests Schedule and Strategy Future Work Programme 18

  18. Tunnel News • Sector 3-4: last W bellows closed Tuesday 23 June • Sector 5-6: last W bellows closed Friday 26 June • Sector 1-2: cool-down started • Sector 6-7:objective is to close by end W28 • Large workload: overall 67 M to be rewelded and W to be closed, 46 busbar splices to be resoldered, 25 (x5) spools for US welding

  19. Tunnel News: Sector 4-5 • Connection Cryostat intervention started Monday 23 June: • Resistance measurements (R-long), MB and MQ at 300K • Measurements noisy but confirm the 2 dipole outliers (quads very noisy) • RF Ball Test: passed Wednesday 24 June • There will be no PIM intervention (no preventive replacement in QQBI.7R4, QQEI.11L5, QBQI.8L5) • DN200 work started paint removal (ALARA) • Open W and cut M3 for 2 dipole outliers, Monday 29 June • Splice Quality Control, R16 measurements, gammas • Start splice repair Wednesday (yesterday), ELQA Friday • Plan to close 4-5 end W28

  20. Magnet transport in the tunnel without a single incident SPC June 15, 2009 21

  21. sector 3-4 : Magnet repair in SMI2 22 SPC June 15, 2009 22

  22. Last Repaired Magnet (SSS) going down (30/4/2009) 23 SPC May 4 2009 SPC June 15, 2009 23

  23. Repair of QRL service module in S3-4 After repair Before repair Q27 24

  24. Beam & Insulation VacuumBending Sections (Arcs) and Experimental Areas On schedule and under control • Beam Vacuum • All beam vacuum pipes in the bending sections (arcs) are completed • Two sectors 3-4 and 4-5 still pending for the aperture check (ball test) • Magnet insulation Vacuum • 1-2: no delay expected, closing under control • 2-3: @ cold • 3-4: no delay expected, closing under control • 4-5: pending to the aperture check and activities to be made. Activities already scheduled and internalised. • 5-6: no delay expected, closing under control • 6-7: following interconnection consolidation • 7-8: ready for cool down • 8-1: no delay expected, closing of the standalone magnet cryostats under control • Experimental Areas • All are under (pure) Neon atmosphere, pump downs are scheduled 25

  25. DN200 installation (Arc + DS) P6 singularity 2 DN200 / dipole (DS and mid-arc) 26

  26. Protective measures Protection of the IC Opening W bellows IFS covers MLI protection 27

  27. In Triplet DN200 Nozzle for safety valve on the rigid sleeve between Q3 and Q2 28 Nozzle for safety valve on the rigid sleeve between Q2 and Q1

  28. Main Cryoboxes (DFBA) - Machining of doors started W23 - Consolidation rate: ~ 1.5 week per sector (including logistics & excluding deflector work) - Deflector Interference with survey equipment to be studied Prototype valve under test: Leak tightness OK 29

  29. SSS with vacuum barrier anchoring Withstand longitudinal load of 240 kN A total of 104 SSS with vacuum barrier in 8 sectors Q15L2 30 O. Capatina EN/MME, LMC, 4th of March 2009 30

  30. IT anchoring consolidation “case by case” approach DFBX in 2 and 8 Q1 bumpers Q1 in 2L DFBX Q3 in 8R D1 31

  31. Enhanced QPS 32

  32. Preliminary Results from Powering Tests – Weekend of 27-28 June Inductive Compensation: The pre-programmed parameters were sufficient for steady ramps (constant dI/dt). Precision Busbar Splice Measurements: Very satisfactory results were obtained immediately in the RB circuit. 1.28 nOhm for segment DCBA.13R2.L (long segment including 3 joints) with measuring plateau of 10 mins Powering both QF/QD circuits gave resistances typically 10 nOhm for the 110 m long busbar segment with 8 splices.

  33. Preliminary Results from Powering Tests – Weekend of 27-28 June SymQ: Verified in Standard crate and Studied through Labview application with separate monitoring crate. The 4-dipole algorithm operates correctly During ramping with up to 10 A/s the residual signals remains insignificant. The nQPS crate powering system (the two Power Packs), the new WorldFip link and all the new Software tools worked perfectly.

  34. Splice Resistance Measurements 35

  35. 1-2 M3 splice resistance (copper) (A18-B17)L2 +35μΩ R16→+17μΩ (28.0μΩ, 11.2μΩ, 13.4μΩ) (B32-A33)R1 +39μΩ R16→+53μΩ (52.3μΩ, 24.9μΩ, 10.8μΩ) (B29-A30)R1 +45μΩ R16→+44μΩ (22.8μΩ,28.5μΩ, 29.9μΩ) Courtesy R. Flora, C. Scheuerlein (C30-A30)L2 +36μΩ R16→+29μΩ (41.3μΩ, 12.3μΩ) (C17-A17)L2 +36μΩ R16→+42μΩ (39.6μΩ, 26.6μΩ) The cool-down of S12 was delayed in order to perform this “warm” measurement 5 June, 2009 Francesco Bertinelli 36

  36. 1-2 M3 splice repair Courtesy C. Scheuerlein 5 June, 2009 Francesco Bertinelli 37

  37. Summary • The enhanced quality assurance introduced during sector 3-4 repair has revealed new facts concerning the copper bus bar in which the superconductor is embedded. • Tests have demonstrated that the process of soldering the superconductor in the interconnecting high-current splices can cause discontinuity of the copper part of the busbars and voids which prevent contact between the superconducting cable and the copper • Danger in case of a quench • Studies are now going on to allow: • To find a safe limit for the measured joint resistance as a function of the current in magnet circuits (max energy in the machine) • Faster discharge of the energy from circuits

  38. Powering and Tunnel Access Restrictions 39

  39. SD4: Conditions for working at height UX45: Solution for access being investigated Access to CMS subject to conditions SD6: Conditions for working at height Access restrictions for Powering Phase II in Sector 5-6 or 45 SPC June 15, 2009 40

  40. Results Powering Tests 60A – all commissioning 80/120A – most commissioned 600A – many circuits commissioning started, some issues IPQ/IPD – commissioned for step in phase I RB – commissioned to 1 kA RQ - commissioned to 1 kA Inner triplet – not started Performed 74 % of the Phase I + Phase II steps 41 R.Schmidt, LMC 1/7/2009

  41. LHC Schedule 42

  42. Strategy for Start-Up • ~3 weeks delay with respect to baseline due to • R-long and R-16 measurements • Splice repairs • Delay in cool down of S12 and repairs of splices • (Re-warming of S45) • BUT the story of the copper stabilizers goes on • Need to measure the remaining sectors (S23, S78, and S81) ?at 80K • Need to understand the extrapolation of measurements at 80K to 300K • Measurement of variation of RRR with temperature • Need to gain confidence in the simulations for safe current • Compare different simulation models/codes 43

  43. Strategy Measure S45 at 300k (DONE) will be redone W28 (better temperature stability) Measure remaining 3 sectors (at 80K); last one (81) presently foreseen at beginning August Measure variation of RRR with temperature during cool down Update simulations (3 simulation models) of safe current vs resistance of splices Decay times of RB/RQ circuits following a quench (?quench all RQs) Determine which splices would need to be repaired as a function of safe current (beam energy) Evaluate time needed to heat up to 300K and repair these splices Prepare scenarios of safe operating energy vs date of first beams Discuss with Directorate and experiments and decide on best scenario. Preferred scenario :highest possible energy associated with earliest date (what is the maximum energy with no repairs needed) At start-up confirm all splice resistance measurements at cold using new QPS

  44. Simulations: Maximum safe currents vs copper joint resistance Warm (300K) 45

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