Eric Prebys, Fermilab Director, US LHC Accelerator Research Program (LARP) February 16, 2010

 Background  Previously assumed upgrade schedule  Key Results from Chamonix  LARP Highlights since last meeting  I will present the items that were discussed at CERN, annotated as appropriate. February 16, 2010 Eric Prebys - LARP Annual DOE Briefing 2

 Initial operation (now)  Ramp up to 1x10 34 cm -2 s -1  Phase I upgrade  After ~2 years of operation (~2014)  Replace 70 mm triplet quads with 120 mm quads   * goes from 50->30 cm  Linac4 to increase PSB injection energy to reduce space charge effects  Luminosity goes to 2-3x10 34 cm -2 s -1  Phase II upgrade  After Phase I triplet burns up (nominally ~2020)  Peak luminosity goal: 1x10 35  Details still under study New technology for larger aperture quads (Nb 3 Sn) crab cavities? Improved injector chain (PS2 + SPL)? No major changes to optics or IR’s Possible Significant Changes February 16, Eric Prebys - LARP Annual DOE Briefing Focus of APUL LARP Magnet Program

 Energy  Joints not reliable above 3.5 TeV  Run at for ~fb -1 or roughly end of 2011  Shut down for ~18 months to do all repairs to get to 7+7 (or as high as quench problem will allow).  Collimation  Initial (Phase I*) collimation only good to a luminosity of a few  A plan is in place for collimation which is good to “ultimate” luminosity of a few Schedule being worked out Will involve LARP collimators, if they survive tests.  Crab Cavities  In a major shift from last year, crab cavities are now considered part of the base line plan for the Phase II upgrade  LARP has played a major role in this February 16, 2010 Eric Prebys - LARP Annual DOE Briefing 4 *note confusing inconsistent “phases” for collimation and triplet upgrade

February 16, 2010 Eric Prebys - LARP Annual DOE Briefing 5 Projection assuming Phase II collimation and Phase I upgrade done in 2013/2014 shutdown* *R. Assmann, “Cassandra Talk” Limit of Phase I (existing) collimation

 The current studies seem to suggest that the bottleneck in the LHC will be not be the (50 year old) PS, but rather the SPS or the LHC itself.  CERN is forming a working group to discuss the fate of PS2  Expect decision in ~6 weeks  We consider it unlikely at this point February 16, 2010 Eric Prebys - LARP Annual DOE Briefing 6 Intensity Limitations (10 11 protons per bunch) PresentSPL-PS22GeV in PS LINAC44.0 PSB or SPL PS or PS SPS1.2 LHC??? Proposed alternative: increasing PSB energy

 Two years at 3.5 TeV  2010: should peak at and yield up to 0.5 fb -1  2011: ~1 fb -1 at 3.5 TeV  2012: splice consolidation (and cryo collimator prep.)  2013: 6.5 TeV - 25% nominal intensity  2014: 7 TeV – 50% nominal intensity February 16, Eric Prebys - LARP Annual DOE Briefing Aggressive Year Months energy beta ibnbPeak Lumi Lumi per month Int Lumi Year Int Lumi Cul e e e e Joint Repair e e e e fb -1 *From Mike Lamont’s Chamonix talk

 In 2014, the LHC will optimistically accumulate ~10’s of fb -1, and the luminosity will still be increasing.  The lifetime of the existing triplet magnets is ~500 fb -1  Is it likely the experiments will want to stop for a year upgrade followed by a year of re-commissioning?  Consider two possibilities  Delayed scenario Phase I upgrade delayed until ~2017 Phase II upgrade delayed until ~2023  Skip Phase I entirely Phase II still in 2020, or maybe even earlier  CERN is supposed to make a decision regarding the Phase I upgrade in about 6 weeks  Need to start moving on magnet production if it’s really going to happen. February 16, 2010 Eric Prebys - LARP Annual DOE Briefing 8

 Instrumentation  Luminosity monitors fully installed and ready at IP1 and IP5 Intensity and energy too low to see so far Analyzing potential for 3.5 TeV operation  Schottky DAQ application complete (LAFS), ready for data Intensity too low to see so far Issues with remote data access  AC Dipole ready for use Awaiting permission for commissioning  Synchrotron Light Monitor Already delivering useful information about beam Used to measure emittance growth February 16, 2010 Eric Prebys - LARP Annual DOE Briefing 9

 Instrumentation (cont’d)  LLRF tools developed at SLAC (J. Fox, et al) were very useful in optimizing LHC RF system February 16, 2010 Eric Prebys - LARP Annual DOE Briefing 10

 What is the model for remote access to data?  This has been an issue for Schottky already. (Working to put a liaison in the controls group)  Handoff and support?  eg, who’s responsible for software?  Increased commissioning time for lumi, given new energy schedule (agreed to help during commissioning of Lumi while energy ramps up, but CERN will maintain)  What will be the impact of IR upgrade(s) (TAN rebuilt) on the luminosity monitor? (There will still be a slot for the Lumi in the new TAN)  What is the future of the AC dipole?  Should LARP continue to support it? (agreed we need to work on this)  Are there additional instrumentation topics where we could contribute? (no big ideas) February 16, 2010 Eric Prebys - LARP Annual DOE Briefing 11

 Rotatable Collimators  Continued good coordination with CERN Phase II collimation plan  On track for prototype delivery, August 2010  Planning for SPS installation and testing after the 2010 run.  Will test in HiRadMat facility when facility is complete (mid-2011).  Crystal Collimation  Exciting demonstrations from both T980 (FNAL) and UA9 (CERN)  Test proposed in LHC T980 UA9 February 16, 2010 Eric Prebys - LARP Annual DOE Briefing 12

 New idea: hollow electron lenses as collimators/scrapers  Lots of interest from CERN  Demonstration of hollow beams at FNAL February 16, 2010 Eric Prebys - LARP Annual DOE Briefing 13

 Are LARP plans consistent with CERN expectations regarding prototyping and testing of the rotatable collimators?  Current plan is one prototype for both SPS and HiRadMat facility.  Do we need two? (Yes)  If rotatable collimators are found acceptable for CERN use, what model is envisioned for construction  CERN?  US project (a la APUL)? (either is a possibility. Needs to be discussed)  Are crystal collimation and/or hollow electron beam seen as possibilities for the LHC future?  Given our limited resources, how much effort should LARP commit? (very excited about hollow electron beams as scrapers; want to keep investigating crystal collimation)  Are there other ways LARP can contribute to the collimation effort?  eg, redirect accelerator physics effort from electron cloud and/or beam beam? (Can probably use help) February 16, 2010 Eric Prebys - LARP Annual DOE Briefing 14

 e-cloud  E-cloud simulations have focused on developing the specifications for an RF feedback system in the SPS, based on MD periods in 2008 and  These studies have also contributed to new vaccuum chamber design Prototype inserts to be installed in the SPS. Data Simulation February 16, 2010 Eric Prebys - LARP Annual DOE Briefing 15

 Beam-beam  Electron lens Gaussian gun installed in Tevatron Evaluating multiple simulation tools for Tevatron, RHIC, and LHC BNL received $4M in stimulus money to work on electron lenses for RHIC, and we’re investigating how to profit from that program. February 16, 2010 Eric Prebys - LARP Annual DOE Briefing 16

 Beam-beam (cont’d)  Flat beam studies for LPA solution C. Bhat undertook a series of studies in PS to investigate flattening bunches with higher harmonic for LPA solution Theory: Measurements and simulation at 26 GeV in PS February 16, 2010 Eric Prebys - LARP Annual DOE Briefing 17 Note: Bhat starts as an LTV later this year

 Accelerator physics is one of the areas where LARP can make significant contributions to the LHC  This is because much of the scientific effort comes “for free” from the labs  Is it CERN’s impression that we are using our resources as effectively as we can?  Electron cloud? (Very important to PS2 and SPS)  Beam beam? (Calculations are important; agreed we should keep an eye on RHIC wrt electron lens)  Are there other areas where we can assist?  Collimation? (Very likely)  Crab cavity issues besides cavity design? (Part of the greater crab cavity issue) February 16, 2010 Eric Prebys - LARP Annual DOE Briefing 18

 Crab cavities have now become the base line plan for Phase II luminosity and luminosity leveling.  LARP has played a major role in bringing crab cavities to this point, however the resources needed to fully manage this effort are well beyond LARP  The infrastructure requirements alone demand a central CERN role. (They agree)  Discussion: What are CERN’s plans to move forward with the crab effort and how can we best contribute?  (They don’t have a plan, but are working on one) February 16, 2010 Eric Prebys - LARP Annual DOE Briefing 19

 LARP has planned to commit significant resources to the PS2 white paper.  Agreed to write chapter on collective effects and feedback  Uli Wienands is currently here as a Long Term Visitor to coordinate the effort  In light of Chamonix, need to think about re-scoping  We don’t want to put a lot of effort into a paper if the project isn’t going to go forward.  Consider a de-scoped conceptual design to be completed this calendar year?  Given our interest in collective effects, does it make sense to make the studies generic enough that they’re also applicable to a consolidation of the PS?  (CERN agreed strongly on all points) February 16, 2010 Eric Prebys - LARP Annual DOE Briefing 20

 Toohig Fellows (postdocs)  Helene Felice (LBNL) ended Toohig Fellowship, now LBNL staff  Riccardo di Maria (BNL) Beam beam studies Analyzing SPS e-cloud data Investigating crab cavities  Ryoichi Miyamoto (BNL) AC Dipole Luminosity monitor  Dariusz Bociam (FNAL) Modeling heat transfer in Nb 3 Sn magnets Temperature effects on Nb 3 Sn conductor February 16, 2010 Eric Prebys - LARP Annual DOE Briefing 21

 Long Term Visitors  Steve Peggs (BNL) UA9 (Now moved on to ESS)  Jim Strait (FNAL) Played an important role in data analysis and diagnostic development for superconducting joints following Sep. 19.  Alan Fischer (SLAC) Significantly improved optical design of synchrotron light monitor  Elian Gianfelice-Wendt (FNAL) Commissioning  Rama Calaga (BNL, former Toohig Fellow) Commissioning, coordinating crab cavity effort  Uli Wienands (SLAC) Coordinating US PS2 effort, UA9, and LHC machine studies  Chandra Bhat (FNAL) Starting later this year to work on flat bunches for LPA.  Discussion: Are there other efforts that could benefit from an increased US presence? (Nothing specific, but agreed that the LARP personnel had been very effective) February 16, 2010 Eric Prebys - LARP Annual DOE Briefing 22

LARP Magnet Development Chart Completed Achieved 200 T/m 1 st test 4/2010 Length scale-up High field Accelerator features February 16, Eric Prebys - LARP Annual DOE Briefing

 The 54/61 conductor which we have traditionally used showed instability problems at 1.9K  These appear to be solved with the finer filament 108/121 conductor  The 108/127 conductor will be the choice for all future magnets. SSL 4.4K SSL 1.9K TQS02c test (CERN) TQS03a test (CERN) SSL 4.4K SSL 1.9K February 16, 2010 Eric Prebys - LARP Annual DOE Briefing 24

 The first LQ met 200 T/m design spec !!,  However, based on TQ results, we expect it to go higher  Believe this can be done by mechanically shimming the coils First long quad February 16, 2010 Eric Prebys - LARP Annual DOE Briefing 25

Winding/curing (FNAL) Reaction/Potting (BNL and FNAL) Instrumentation and heater traces (LBNL) February 16, 2010 Eric Prebys - LARP Annual DOE Briefing 26

 Structural pre-assembly complete  Will be tested in 2010 Structure assembly Layer 1 Winding Layer 2 Winding February 16, 2010 Eric Prebys - LARP Annual DOE Briefing 27

 : complete technology demonstration/qualification LQ addresses all length-related issues HQ addresses performance limits and accelerator features  : full scale prototypes and production  Preparations ( ): Converge on design specifications Project planning, infrastructure upgrades  Nb 3 Sn design options and timelines: 120 mm aperture & <4 m length: ~2016 Larger aperture & longer length: ~2018 Discussion: How does this match with CERN’s plans and expectations? (This makes sense, given the earliest conceivable Phase II date) February 16, 2010 Eric Prebys - LARP Annual DOE Briefing 28

February 16, 2010 Eric Prebys - LARP Annual DOE Briefing 29

February 16, 2010 Eric Prebys - LARP Annual DOE Briefing 30

 In a major shift from last year, crab cavities have gained significant priority in CERN’s overall planning February 16, 2010 Eric Prebys - LARP Annual DOE Briefing 31

Kills Phase I Test February 16, 2010 Eric Prebys - LARP Annual DOE Briefing 32

 In response to requests from CERN, LARP has organized significant effort to support the PS2 white paper (nominally due in 2012)  Ultimately endorsed by review committees, the member labs and DOE  Committed to writing the “Collective Effects and Feedback” chapter:  Space-charge: check results for validity, scan working point, effect on lattice functions (if possible). Add E-ramp.  Instabilities: Continue (Cu-)coating investigations; impedance of components as available.  e-Cloud: include quadrupoles in build-up model, refinement of beam-instability estimates.  Feedback: Spec. needed to deal with res. wall growth time(?)  IPM needs re-grouping.  Uli Wienands is currently at CERN as a Long Term Visitor to coordinate effort  But… February 16, 2010 Eric Prebys - LARP Annual DOE Briefing 33

Made the important technology decision between “collared” (traditional) and “shell” pre-load design: all future LARP work will focus on shell *see G. Sabbi, CERN BE Seminar, Jan. 12, 2010, for details February 16, 2010 Eric Prebys - LARP Annual DOE Briefing 34

 Schottky detector  Used for non-perturbative tune measurements (+chromaticities, momentum spread and transverse emmitances)  Tune tracking  Implement a PLL with pick-ups and quads to lock LHC tune  Investigating generalization to chromaticity tracking  AC dipole  US AC dipole to drive beam  Measure both linear and non-linear beam optics  Luminosity monitor  High radiation ionization detector integrated with the LHC neutral beam absorber (TAN) at IP 1 and 5.  Low level RF tools  Leverage SLAC expertise for in situ characterization of RF cavities  Synchrotron Light Monitor  Not originally LARP project  Optics significantly improved by Alan Fisher  Personnel  Toohig Fellowship Postdoc program  Long Term Visitors February 16, Eric Prebys - LARP Annual DOE Briefing

 Rotating collimators  Can rotate different facets into place after catastrophic beam incidents  Aim for prototype in CY09  Crystal Collimation  CRYSTAL Collaboration  T980  Beam-beam studies  General simulation  Electron lens  Wire compensation  Flat beam studies  Electron cloud studies  Study effects of electron cloud in LHC and injector chain February 16, Eric Prebys - LARP Annual DOE Briefing

 Coordination and basic lattice design  Linear correction systems  Non-linear dynamics and correction systems  Collective effects and feedback systems  Space charge studies  Impedance estimates and instabilities  e- cloud effects and vacuum system requirements  Damping system specifications  Collimation aspects  Machine protection  Instrumentation specifications and commissioning strategy *M. Benedikt and Y. Papaphilippou LARP will write this chapter February 16, Eric Prebys - LARP Annual DOE Briefing

Coax LOM/SOM coupler WG HOM coupler Power coupler  At September review, CERN formally endorsed crab cavities for phase II  Contingent on a plan to operate system safely!!  They cancelled a proposed Phase I test of an 800 MHz cavity and recommended focusing all efforts on the final solution.  Because of space limitations, will probably require “compact” cavity.  R&D options might include tests of the KEK cavity at the SPS or elsewhere.  LARP is working to decide its proper role:  Overall concept?  Machine protection?  Cavity/cryostat design? SLAC half wave JLAB “toaster” Fermilab “mushroom” February 16, Eric Prebys - LARP Annual DOE Briefing

 Magnet groups at FNAL, BNL, and LBNL working to demonstrate Nb 3 Sn magnet appropriate for use in the LHC Phase II upgrade.  Currently pushing all parameters  Long Quad (LQ): 4m quad with 90 mm aperture  High field Quad (HQ): 1m quad with 130 mm aperture  Accelerator physics questions:  Optical design  Field quality requirements  Beam loss/heat loading issues  Radiation damage.  Working with CERN to assure that we’re in agreement as to what will validate the technology 120 mm aperture Phase I magnets February 16, Eric Prebys - LARP Annual DOE Briefing