larp accelerator systems 16 november 2011 larp cm17/hl-lhc at cern tom markiewicz/slac bnl - fnal-...

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Schedule for Accelerator Systems Parallel Session This Afternoon LARP CM Nov 2011Accelerator Systems - T. MarkiewiczSlide n° 3 / 48

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LARP Accelerator Systems 16 November 2011 LARP CM17/HL-LHC at CERN Tom Markiewicz/SLAC BNL - FNAL- LBNL - SLAC US LHC Accelerator Research Program The LARP Accelerator Systems Program LARP CM Nov 2011Accelerator Systems - T. Markiewicz Instrumentation Completed Schottky Monitor, Tune & Chromaticity FB, AC Dipole Ongoing Commissioning Support for the Lumi Monitor Support for modest LLRF and SLM collaboration Collimation Phase II Collimator Rotatable Collimator Prototype Crystal Collimation at Tevatron (T980) and SPS (UA9) Accelerator Physics Simulation-dominated effort in Beam-Beam Hollow Electron Beam Gun for use as a Collimation Scraper Simulation-dominated study of Ecloud effects High Bandwidth Feedback Control of Ecloud/TCMI in SPS Crab cavity: Cavity Design and related Beam Physics Hi-Lumi Accelerator Physics in support of Magnet Program Completed PS2 Study & Hibernated PSB Study Slide n 2 / 48 Schedule for Accelerator Systems Parallel Session This Afternoon LARP CM Nov 2011Accelerator Systems - T. MarkiewiczSlide n 3 / 48 In 2012 SPS Ecloud FB & Crab Cavity Are Largest LARP AS Budget Items LARP CM Nov 2011Accelerator Systems - T. Markiewicz * SUBSTANTIAL un-billed Labor from, especially, Fermilab NOT included Slide n 4 / 48 Highlights of December 2010 CC10 meeting at CERN Design capable of crossing beams in either H or V preferable No test of KEK-B Cavity in SPS New SLAC Design to Satisfy H-V specification Compact Ridged Waveguide Deflector Tweaking of ODU/JLAB Parallel bar Design for H & V Crabbing Rigid Waveguide and Parallel Bar designs beginning to look similar and agreement to merge designs made SLAC offer to analyze all designs under consideration with Advanced Computing Division tool suite met with approval Rama Calaga no longer LARP funded (Congratulations!!) LARP Crab Leadership & Role of BNL under discussion New full time postdoc for Old Dominion (plus previous student support) Increased support for SLAC ACD Still no consensus for how to projectize effort (& get engineering funds) Pre-CC11 Comments on the LARP CRAB CAVITY Program LARP CM Nov 2011Accelerator Systems - T. MarkiewiczSlide n 5 / 48 MultiPactering Analysis of SLAC Compact 1-D Half Wave Spoke Resonator Cavity LARP CM Nov 2011Accelerator Systems - T. Markiewicz LOM/HOM-v HOM-h FPC Impressive Visualization of Resonant MP Z. Li Slide n 6 / 48 SLAC Ridged Waveguide Deflector for H & V Crabbing LARP CM Nov 2011Accelerator Systems - T. Markiewicz Z. Li Slide n 7 / 48 Current ODU Crab Cavity Design Program LARP CM Nov 2011Accelerator Systems - T. MarkiewiczSlide n 8 / 48 ODU/Niowave Phase II STTR J. Delayen Current Design Example of Multipacting Simulation Using Track3P on ODU Prototype Cavity LARP CM Nov 2011Accelerator Systems - T. Markiewicz Z. Li Slide n 9 / 48 SLAC Accelerator Research Department: J. Cesaratto (newest LARP Toohig Fellow, November 2011) J. D. Fox, M. Pivi, C. Rivetta O. Turgut, S. Uemura (graduate students) BE-RF Group, CERN: G. Arduini, W. Hofle, K. Li, G. Rumolo, B. Salvant LBL: M. Furman, M. Venturini, S. De Santis, J.-L. Vay R. Secondo (graduate student) Transverse Wideband Feedback for Ecloud/TMCI in the SPS Task Leader: John Fox LARP CM Nov 2011Accelerator Systems - T. MarkiewiczSlide n 10 / 48 A vertical excitation system was developed, tested, and installed in the SPS Existing pickups for driving bunch & measuring response Four 100W MHz amplifier array 4 Gsample/sec D/A synched to RF and software tools to drive individual bunches Data collected during the July/August and November 2011 Machine Development runs at the SPS used to understand Ecloud/TMCI dynamics and to develop reduced models and numeric simulations Modeling in WAP, CMAD and Head-Tail Codes Extraction of system dynamics Develop a simplified coupled-oscillator model for feedback design 2011 Ecloud/TMCI Progress LARP CM Nov 2011Accelerator Systems - T. MarkiewiczSlide n 11 / 48 Broadband 100W Mhz amplifiers under construction & test LARP CM Nov 2011Accelerator Systems - T. Markiewicz Sho Uemura Slide n 12 / 48 4 GigaSample/s D/A Synched to RF and software tools to drive individual bunches LARP CM Nov 2011Accelerator Systems - T. MarkiewiczSlide n 13 / 48 Amplifiers Shipped, Installed & Connected to SPS Kicker LARP CM Nov 2011Accelerator Systems - T. MarkiewiczSlide n 14 / 48 A single bunch of stable beam is excited by the amplifier array The excitation system drives the bunch at mode 0, mode 1, etc. frequencies Bunch motion is studied via pickup array and receiver system, digitized at 40 GS/sec. Barycentric, head-tail or higher modes are excited Study dynamics as currents are increased towards instability thresholds Movies ( time domain), and Spectrograms ( frequency domain) Results from Excitation studies LARP CM Nov 2011Accelerator Systems - T. MarkiewiczSlide n 15 / 48 Extraction of system dynamics Development of reduced (linear) coupled-oscillator model for feedback design Inclusion of feedback models in WARP, CMAD and Head-Tail codes Modeling LARP CM Nov 2011Accelerator Systems - T. Markiewicz Kicker signal for all the slices: Vb = 4E-6sin(2(0.185Turns)) eV-sec/m C-MAD result: Vertical displacement of center of the bunch Data: Vertical displacement of center of the bunch Slide n 16 / 48 Develop 4 GS/sec. proof of principle feedback system Identify critical technology options, evaluate difficulty of technical implementation Explore small prototype functional feedback channel for 2012 fab and MD use Evaluation boards being used to explore feedback parameters R. Secondo (LBL) is now working on a equalizer design to process the pickup signals: part of the proof-of-principle system in development for tests at the SPS Both a prototype and full scale feedback system are beyond scope of LARPs budget SPS Kicker Design Study: develop wideband prototype Goal is prototype kicker & feedback installation in SPS in shutdown 2012 Ecloud/TMCI Plan LARP CM Nov 2011Accelerator Systems - T. MarkiewiczSlide n 17 / 48 Funding began summer 2011 with FY11 contingency request and continued in FY12 at same level In line with DOE reviewer comments for AP support of LARP magnet design In line with HL-LHC Accelerator Physics task (Hi Lumi WP2) General agreement by all AP parties that this is good Led by Nikolai Mokhov/Fermilab with MARS-based tools Led by Yunhai Cai/SLAC with suite of agreed upon AP codes Communication with CERN (Bruning et al) and Magnet side required for success This has begun within the context of Hi-Lum Work Package 2 Subtask Leader: M. Giovannozzi Loss Maps & Energy Deposition Studies in Support of Nb3Sn Magnet Design LARP CM Nov 2011Accelerator Systems - T. MarkiewiczSlide n 18 / 48 LHC Beam Dynamics and Collimation Studies at SLAC 19 SLAC members involved Yunhai Cai, Yi Jiao, Yuri Nosochkov, Lanfa Wang, Min-Huey Wang, Yiton Yan CERN members in contact and for discussion M. Giovannozzi, R. Assmann, Y. Levinsen, E. Mcintosh, A. Rossi, F. Schmidt Lattice: ATS collision scheme 4444 with *=15/15 cm at IP1 and IP5 Codes: SixTrack, MAD-X. Proposed topics of studies Field quality specifications for the new triplet quadrupoles. Computation of collimation loss maps. High order map analysis. Chromatic effects on beam cleaning efficiency. Chromatic aberrations for the collimation system. 6-D beam-beam effects. Status and Highlight 20 Current studies: Numerous dynamic aperture studies are carried out to declare the first round triplet tolerance error table based on global scaling of the field coefficients. Preliminary calculation of the beam loss map is done for the ATS collision lattice 4444. Further studies: Analysis of sources for dynamic aperture reduction (effects of arc beta beat and non-paired sextupoles). The Second round triplet tolerance error table is to be based on relaxing field error coefficients one-by-one -- more realistic for the magnet design. more detailed calculation of collimation beam loss map. Future studies: Analyses of High-order maps, chromatic effects, and 6-D Beam-beam effects for the ATS lattice. Highlight: First round tolerance table in the next slide. ATS 4444 First Round IT Tolerance Error Table (R ref = 50 mm) 21 NormalUncertaintyrmsSkewUncertaintyrms B A B A B A B A B A B A B A B A b A B A B A B A B A B A B A LARP CM Nov 2011Accelerator Systems - T. MarkiewiczSlide n 22 / 48 15mm Hollow Electron Gun LARP CM Nov 2011Accelerator Systems - T. MarkiewiczSlide n 23 / 48 Hollow Electron Beam Gun in Tevatron LARP CM Nov 2011Accelerator Systems - T. Markiewicz 18 experiments Tail of selected bunch depopulated Control bunches & core of selected bunch unaffected Slide n 24 / 48 Excellent progress in understanding of hollow beam collimation Many new observations: halo removal rates, effects on core, diffusion, fluctuations in losses, collimation efficiencies,... Sample HEBC Results: Selected & Control Bunch Intensity vs. Beam Size LARP CM Nov 2011Accelerator Systems - T. MarkiewiczSlide n 25 / 48 Sample HEBC Results: Signal on Gated Loss Monitor for Selected & Control Bunch LARP CM Nov 2011Accelerator Systems - T. MarkiewiczSlide n 26 / 48 New 25mm Hollow Gun for Stronger Scraping LARP CM Nov 2011Accelerator Systems - T. Markiewicz 25 mm diameter cathode vs. 15 mm previously 3A at 5 kV vs. 1A Technical feasibility study Currently assembled, installed at test stand Bakeout, cathode heating Slide n 27 / 48 Discussions of Bringing Electron Lens Hardware to CERN Underway LARP CM Nov 2011Accelerator Systems - T. MarkiewiczSlide n 28 / 48 Luminosity Monitor Commissioning Status A.Ratti, H. Mathis, M. Stezelberger, M. Placidi LBNL June 8, Lumi Status All four devices (two per IP) have been functioning very reliably since the beginning As single bunch luminosity increases, we are moving from counting mode (saturating) to pulse height mode (not effective at lower lumi) FLUKA modeling continues to provide useful support June 8, Lumi Update since the June DOE review Modeling Completed integration of the FLUKA model of the IPs (from CERN) with the detailed LBL model of the TAN and BRAN Summer Student (D. Nguyen UT Austin) Completed transition to FLUKA 2011 Improved results of crossing angle calculations at 3.5, 5 and 7 TeV per beam June 8, Energy Deposition per p-p collision vs crossing angle (from FLUKA) Ecross = (E1 + E4) (E2 +E3) E1 + E2 + E3 + E4 June 8, Operational Experience Continued to develop operator user interface for use in the CCC All software effort thanks to Elliott McCrory (FNAL) Coordinated at CERN by Terri Lahey (SLAC) This GUI is starting to be used in CCC See example next Becoming a tool for beam physics measurements. Can show: Beam beam effects Emittance growth June 8, GUI diagnostics example Example from Aug. 6 (fill 2007) Emittance blowup of one batch during injection Disappointing early luminosity GUI was used to identify which batch immediately June 8, New GUI for use in the CCC Luminosity Atlas and CMS Emittance Atlas and CMS B by B ATLASB by B CMS B by B ATLAS B by B CMS System Parameters Bad Batch LARP involved with SLM (Alan Fisher, SLAC) and Collimation SLAC interest (SSRL) independent of LHC-tested October 2011 Use a Digital Micro Mirror Device (DMD) as an ADJUSTABLE MASK to black out light from beam core so can see halo Suggested by Karsten Welch, EU funded DITANET: students may be available Synchrotron Light Based Halo Monitoring LARP CM Nov 2011Accelerator Systems - T. MarkiewiczSlide n 36 / 48 DMD Masking Experiments at SPEAR3 Oct-Nov 2011 Intense stored beam (few nC) Oscillating injected beam (~30pC) Turn #1 mask diffraction Ralph Fiorito, A.Shkvarunets, H.Zhang University of Maryland J.Corbett, A.Fisher, K.Tian SLAC T.Mitsuhashi (KEK, Japan), W.Mok (Visiting scientist), J.Kamp (Summer student) Turn #2 Turn #6 Turn #3 Turn #4Turn #5 injected beam Incident beam 5x Magnification DMD Gated Camera w/intensifier Airforce Target Calibration J. Corbett Measuring the Size of Every Bunch Every Second Slowly rotating wheel (0.25 Hz) scans 3 thin slots across the image of the beam PMT after slot gives pulse for each bunch As slot passes by, digitize 100 pulses for each bunch Projects each bunch onto x, y, and 45 axes Beam 45 slot Y slot X slot X profile of a bunch in SPEAR3 15-m wide slot in foil Al discs to support foil A. Fisher LARP CM Nov 2011Accelerator Systems - T. MarkiewiczSlide n 38 / 48 LHC LLRF and Longitudinal Beam Dynamics Purpose: LHC non-linear beam dynamics-RF station simulation and system model. The model captures engineering level implementation details. People: SLAC: J.D.Fox, C. Rivetta, D. Van Winkle CERN: P. Baudrenghien, A. Butterworth, T. Mastorides, J. Molendijk Results in : 1.The LLRF configuration tools have been used by the CERN BE-RF group to remotely commission the LLRF feedback loops of the RF stations during start up in both November 2009 / February Tools reduced commissioning from 1.5 days/station to 1.5 hours/station. Model based configuration adds consistency and reliability. CERN BE-RF group have repeatedly expressed their support and proposes Continue work to test the 1-turn feedback functionality of the commissioning tools Expansion of the tools to control the smooth increase of the High Voltage and Klystron current with beam, from 450 GeV conditions to ramping/physics Beam Diffusion Studies and LLRF System Noise Contributions 2.RF Noise Effect on Beam Diffusion Studies Developed theoretical formalism relating the equilibrium bunch length with beam dynamics, accelerating voltage noise, and RF system configurations. Conducted measurements that confirmed the formalism and models identified performance-limiting components RF reference noise introduced by controller in mod/demodulation process Intrinsic noise in the controller feedback boards set an allowable noise threshold for acceptable lifetime. 3.Predictions of beam longitudinal motion and RF station stability limits for future high current/higher energy LHC operations Estimate longitudinal stability margin for 2012 operations. Impact of future LLRF configurations on RF noise levels is being investigated. Two jaw collimator made of Glidcop Rotate jaw after 1MJoule beam abort failure accident occurs Each jaw is a cylinder with an embedded brazed cooling coil No vacuum-water braze; 12kW/jaw cooling; minimal thermal distortion Maximum radius cylinder possible given beam pipe separation 20 2cm wide facets provided for presumed rare beam abort accidents The LARP Rotatable Collimator Prototype Candidate for a Phase II Secondary Collimator Advantages: Not exotic material High Z for better collimation efficiency & more debris absorption Low resistance for better impedance Elemental for high radiation resistance Disadvantages: Glidcop WILL be damaged in asynchronous beam abort LARP CM Nov 2011Accelerator Systems - T. MarkiewiczSlide n 41 / 48 Collimator Assembled 13-Mar-11 Mechanical & Resistance Tests Good LARP CM Nov 2011Accelerator Systems - T. MarkiewiczSlide n 42 / 48 After welding tank to base and copper cooling tubes to feedthroughs at bottom of bellows discover major water-to-vacuum leak in each cooling tube Each tube was tested at various stages in fabrication process but not at every stage of fabrication and not at final stage Since then Cap the tubes and: Test rotation mechanism under vacuum Good 5 week vacuum bakeout, pressure test and RGA scan- few x E-9 torr Test rotation mechanism after bakeout One gear jammed; repaired easily; cause understood Cut open the tank, cut out the jaws & find leaks Jaw A has crack in tube wall in stress free area: repaired Jaw B leak isolated to small zone at rear of collimator Jaw material being cut now to expose tube for repair Discussions with CERN, SLAC, LARP & DOE as to best course of action Vacuum Tests LARP CM Nov 2011Accelerator Systems - T. MarkiewiczSlide n 43 / 48 When Cooling Tubes Capped and Tank Pumped Vacuum IS Good Pressure: 1.9E-5 Torr (Cold Cathode Gauge on tank) Leak rate: 5.9E-10 mbar-l/sec (on the Adixen input) Pressure rate of rise Leak rate of ~1E-4 torr/hour LARP CM Nov 2011Accelerator Systems - T. MarkiewiczSlide n 44 / 48 Final RGA after 5 week 250C bakeout (Blue bar is ideal level), P=4.4E-9 torr LARP CM Nov 2011Accelerator Systems - T. MarkiewiczSlide n 45 / 48 Crack in Copper Magnet Conductor Used for Winding First Prototype Jaw LARP CM Nov 2011Accelerator Systems - T. Markiewicz Tube is not Class 1 OFE was thought to be OK for a prototype to get started Suspect weakening in material at crystal grain boundaries after last of many high temperature firings Slide n 46 / 48 Leak in OFE Class 1 Copper Tubing Isolated to Area Indicated LARP CM Nov 2011Accelerator Systems - T. Markiewicz Suspect damage at tack welds used during assembly Slide n 47 / 48 Major shift in emphasis away from Luminosity Monitor and Rotatable Collimator to the SPS Wideband FB Control of Ecloud/TCMI and the Crab Cavity New effort in Accelerator Physics in support of HL-LHC and the LARP magnet program Superb new experimental results from the Hollow Beam Electron Gun and interest in bringing it to CERN Continued excellent work in the Luminosity Monitor, LLRF, SLM, as well as the Crystal Collimation experiments & Schottky monitor (apology) Continuing effort to recover the Rotatable Collimator Phase II Prototype program. Summary LARP CM Nov 2011Accelerator Systems - T. MarkiewiczSlide n 48 / 48