RHIC Accelerator Improvement and Capital Equipment Projects Wolfram Fischer

1. RHIC Accelerator Improvement and Capital Equipment ProjectsWolfram Fischer 28 June 2010 RHIC Operations Review

2. Content • AIP overview for FY2010-2016,goals, project selection, and projects • Stochastic cooling and 56 MHz upgrade status, impact on performance and budgets (including ARRA) • Electron lens upgrade status, impact on performance and budgets (including ARRA) • Other AIP projects, current and planned • Accelerator capital equipment overview 2

3. Delivered Integrated Luminosity and Polarization Heavy ion runs Polarized proton runs Integrated luminosity L [pb-1] Integrated nucleon-pair luminosity LNN [pb-1] Nucleon-pair luminosity: luminosity calculated with nucleons of nuclei treated independently; allows comparison of luminosities of different species; appropriate quantity for comparison runs. AIP and capital projects critical for luminosity and polarization increases

4. RHIC luminosity and polarization goals

5. AIP and capital projects – selection process • Annual review (usually starting with RHIC Retreat) to identify • Performance limiting processes or equipment • Items that will need replacements (equipment at end of life, particularly single points of failure) • Operational efficiency limits (time, power, other cost) • Performance has 3 dimensions: • Luminosity(heavy ions and protons) • Polarization(protons) • Flexibility (species and energy change, new operating regimes) • Then: • Technical solutions are developed • Costs and personnel demands are estimated (initial estimates can be several years out, are reiterated) • Projects are ranked in time considering performance gain,funding profile, and available personnel 5

6. RHIC Retreat 2010 https://indico.bnl.gov/conferenceOtherViews.py?view=standard&confId=252 6

7. Overview AIP and capital projects FY2010 – 2016 less well defined FY2011: Presidents budget, FY2012-16: 3.5% annual escalation 7

8. RHIC heavy ions – luminosity limits • Intrabeam scatteringLeads to debunching and transverse emittance growth Bunched beam stochastic cooling during stores + stronger long. focusing • Chromatic abberations with small b*With b* = 60 cm could not correct nonlinear chromaticity with beam-based method (momentum aperture too small), retreated to b* = 70 cm •  Include chromatic corrections in lattice design • Instabilities at transitionLimit bunch intensity, driven by impedance and electron clouds  Reduce SEY in arcs (straights are NEG coated), feedback 2004 no cooling series of AIP/capital projects intensity loss after transitionat end of bunch trains future AIP/capital projects 8

9. RHIC – 3D stochastic cooling for heavy ions longitudinal pickup longitudinal kicker (closed) Y h+v pickups B h+v kickers horizontal kicker (open) horizontal andvertical pickups B h+v pickups Y h+v kickers verticalkicker(closed) 5-9 GHz, cooling times ~1 h M. Brennan, M. Blaskiewicz, F. Severino, Phys. Rev. Lett. 100 174803 (2008); PRST-AB, PAC, EPAC 9

10. RHIC – bunched beam stochastic cooling for heavy ions M. BrennanM. Blaskiewicz et al. • Longitudinal cooling since 2007 • First transverse (vertical) cooling in 2010 14 Jan 2010 • So far stochastic cooling increased average store luminosity by factor 2 • Expect another factor 2 with full 3D cooling • Open issues: • Vacuum leaks at feedthroughs • Mechanical motion of longitudinal kickers • Cross-talk between Blue and Yellow vertical system (addressed by 100 MHz shift in Blue) • Construction, installation, and commissioning of horizontal systems 10

11. 56 MHz SRF for heavy ions – under construction (I. Ben-Zvi et al.) • Longitudinal profile at end of store • even with cooling ions migrate into neighboring buckets • can be reduced with increased focusing 40 ns Average luminosity vs. vertex size + 56 MHz SRF full 3D cooling • l/4 Ni resonator • common to both beams • beam driven • 56 MHz, 2 MV demonstrated 2010 long. + ver. Cooling (10x design value) Calculations by M. Blaskiewicz 11

12. RHIC stochastic cooling and 56 MHz SRF upgrades • Obtain RHIC II performance (= order of magnitude more heavy ion luminosity) without major upgrade (previously planned for electron cooling, ~$100M): 12

13. RHIC stochastic cooling and 56 MHz SRF • Blue and Yellow horizontal stochastic cooling (ARRA AIP): • Funding : $4.0M (06/25/09) • Cost-to-date : $1.7M (of which $163k labor w/o overhead) [as of 05/27/10] • Pacing item: kicker tanks, order placed • Expected completion: 07/2012 • depending on delivery schedule, installation in summer 2010 may be possible • if not, installation in summer 2011still allows to meet scheduled completion date 90 rotated version of vertical kickers vertical cooling was used in operation in 2010 13

14. RHIC stochastic cooling and 56 MHz SRF Horizontal stochastic cooling AIP (ARRA) schedule 14

15. RHIC stochastic cooling and 56 MHz SRF 56 MHz SRF AIP schedule 15

16. RHIC protons – polarization and luminosity limits • AGS : proton bunches with high intensity, high polarization and low emittance polarized source upgrade (under way) AGS horizontal tune jump system (tested in 2009-10) • RHIC: polarization transmission to 250 GeV acceleration near 2/3 resonance (tested in 2010) • RHIC: intensity transmission to 250 GeV beam dump system modifications (thicker beam pipe in dump) Yellow ramp transmission (9 MHz rf system) • RHIC: peak luminosity and luminosity lifetime reached lower b* limit at 100 GeV(not necessarily a problem at 250 GeV) electron lenses allow for larger beam-beam parameter(under way) capital project 2 AIPs (ARRA + regular) 16

17. Head-on beam-beam effect and luminosity in RHIC • If 1 of 2 collision can be compensated, gain up to 50% in integrated luminosity under current conditions • Up to factor 2 gain with higher bunch intensity (requires polarized proton source upgrade) Bunches with 1 collision Bunches with 2 collisions Bunch intensities fitted to double exponential functions, then compare [N1(t)/N2(t)]2 17

18. Electron lenses in RHIC – 2 AIPs (1 ARRA + 1 regular) • Polarized proton luminosity limited by head-on beam-beam effect (DQbb,max 0.02) • Basic idea:In addition to 2 beam-beam collisions with positively charged beam have another collision with a negatively charged beam with the same amplitude dependence. • 2 electron lenses installed in Tevatron, not used for head-on beam-beam compensation • Exact compensation for: • short bunches • Dyx,y = kp between p-p and p-e collision • no nonlinearities between p-p and p-e • same amplitude dependent kick from p-p, p-e • Only approximate realization possible IP8-IP10 Dyy = 10.9 p IP6-IP10Dyx = 19.1 p 6 papers at IPAC2010: MOPEC026 (overview), THPE100 (long bunches), Y. Luo TUPEC082 (SimTrack), THPE102 (simulations), C. Montag MOPEC035 (beam alignment with bremsstrahlung), C. Montag TUPEB050 (e-lens for e-beam)

19. Electron lenses in RHIC – 2 AIPs (1 ARRA + 1 regular) collector 6 T solenoid, straightness~0.1 rms beam size DC gun: 7 kV, 0.6 A e-beam p-beam • partial (50%)compensation of head-on beam-beam • goal of 2x luminosity increase together with source upgrade(allowing for higher bunch intensity with good polarization) • critical: relative beam alignment (Tevatron experience) requires straight solenoid field lines, good instrumentation (bremsstrahlung monitor – C. Montag, D. Gassner) 19

20. Electron lenses in RHIC – 2 AIPs (1 ARRA + 1 regular) 6D beam lifetime simulation of electron lens (Y. Luo, IPAC2010) Beam lifetime simulations arechallenging – require good modeland supercomputer Nb = 3x1011without and with e-lens Simulations show full benefit of e-lens for Nb > 2x1011(i.e. with source upgrade) 20

21. RHIC electron lenses – 2 AIPs (1 ARRA + 1 regular) • 1st electron lens (ARRA AIP): • Funding : $4.0M (06/25/09) • Cost-to-date : $439k (of which $233k labor w/o overhead) [as of 05/27/10] • Pacing item: superconducting solenoid • Had planned to purchase in industry • Received only 1 bid from 9 bidders contacted(various reasons for no bids – missing production capacity, exchange rate, …) • Bid at about 3x budgeted value (budget for sc solenoid guided by 2 benchmarks: EBIS spare solenoid, Tevatron solenoids for electron lens) • Failed solenoid bidding also delayed project • Solenoid now build in Superconducting Magnet Division,(allows for technically better magnet) • Expected completion: 11/2012 21

22. RHIC electron lenses – 2 AIPs (1 ARRA + 1 regular) • 2nd electron lens (AIP): • Funding : $3.1M (planned for FY2011/12 AIP) • Engineering and tooling cost covered by 1st lens • Expected completion: 11/2012 (same as 1st lens) Electron collector DC electron gun 22

23. RHIC electron lenses – 2 AIPs (1 ARRA + 1 regular) Electron lens (ARRA AIP + AIP) schedule(details under development after changes in the magnet procurement, resource loaded schedule needs ~ 1 month) [So far, have held previously communicated milestones unrelated to superconducting solenoid:gun and collector ready to order (2/10), beam transport ready to order (3/10), diagnostics (06/10).] 23

24. Other AIP projects FY2010 – FY2016 • RHIC cryo control system upgradeTotal AIP funding: $900k (FY2007-10), expected completion: 12/2011 • Replacement of existing controls hardware from early 1990s, upgrade of valve box and re-cooler instrumentation and control, preparation for MCR consolidation • Main Control Room consolidation and upgradeTotal AIP funding: $2.5M (FY2007-10), expected completion: 12/2011 • Control room last updated with Booster commissioning in 1990Plan to have all 24 h personnel in one control room (some functions currently outside)Makes all signals digitalAddresses console shortages with simultaneous operation of RHIC, injectors, NSRL and H-jet, particularly during beam development periodAlso alleviates office space limitations in department • Westinghouse stator insulationTotal AIP funding: $800k (FY2010), expected completion: 12/2011 • Westinghouse is back-up for Siemens Motor-Generator set (failure of Siemens without backup could stop AGS operation by a year)Insulation is 40 years old, at end of useful life (rotor done previously) 24

25. Other AIP projects FY2010 – FY2016 • RHIC low energy coolingTotal AIP funding currently planned: $4.8M (FY2011-14) • RHIC operation recently extended to below nominal injection energy in search of critical point in QCD phase diagram • Luminosity can be enhanced at this energy with electron cooling using the Fermilab Pelletron (last Run’s low energy data being analyzed) • After Au-Au energy scan in 2010, awaiting data analysis of RHIC experimentsand guidance on luminosity demands at low energy • RHIC cold beam pipe in-situ coatingTotal AIP funding currently planned: $4.0M (FY2014-16) • Stainless steel chambers in arcs have high resistivity and high secondaryelectron yieldElectron clouds are limiting heavy ion luminosity through instabilities at transition, affect proton emittance at injection and possibly intensity transmission • RHIC transverse damperTotal AIP funding currently planned: $2.8M (FY2016-) • Addresses transverse instability at transition that limits heavy ion luminosity 25

26. MCR consolidation and upgrade Current MCR, done with Booster 1990Space too limited now • Built building in an high-bay area • lower floor: office space • upper floor: new control room • Expect to use end of next year • Plan to have all 24 h personnel in one control room (some functions currently outside) • Addresses console shortages with simultaneous operation of RHIC, injectors, NSRL and H-jet, particularly during beam development period • Also alleviates office space limitations in department 26

27. e-cooling for low energy collider operation (A. Fedotov et al.) • Considering use of Fermilab Pelletron (used for pbar cooling at 8 GeV)after Tevatron operation ends Cooling into space charge limit DQsc~ 0.05(new collider regime) with cooling Expect up to factor 5more integrated luminosity(depending on energy and DQsc) A. Fedotov et al.HB 2008 without cooling 27

28. Upgrades for heavy ions and polarized protons – in situ-coating A. Hershkovich et al.IPAC2010 SBIR Phase Iapplied for Phase II • Electron clouds limit • Ion intensity (through instability at transition) • Proton emittance at injection, and intensity • Warm parts are largely coated with NEG • Cold arcs are stainless steel, not coated • Need in-situ coating for arcs Current R&D for magnetron mole Test tube coated with Cu 28

29. Capital projects FY2010 – FY2016 • FY2010 – FY2016 • ~$100-300k annually for test and measuring equipment, file servers, laser tracker, and other capital equipment • AGS/RHIC low level rf upgradeTotal capital funding: $1.7M (FY2005-11), expected completion 2012 • Obsolete electronics in low level rf, near to a single point of failure Increase of flexibility and robustnessCommon platform for AGS and RHIC, now also used for EBIS, spin flipper • Access Control System upgradeTotal capital funding: $500k (FY2009-12), expected completion 2013 • Linac, Booster and AGS system sill based on relay technologyObsolete technology with increasing failure ratesWill be replaced with PLC, upgrade also needed for new MCR 29

30. Capital projects FY2010 – FY2016 • Polarized Proton Source upgradeTotal capital funding: $1.1M (FY2009-11), expected completion 12/2012 • Existing source build for DC operation, pulsed operation allows for order of magnitude higher current, which can be used to select core of high polarization(about +5%) and low emittance Includes atomic hydrogen source (Novosibirsk), superconducting solenoid, and polarimeter upgrade • Important performance upgrade for polarized proton program • AGS roughing pumps and vacuum gaugesTotal capital funding: $1.1M (FY2010-12), expected completion 12/2013 • Existing roughing pumps have reached end of life, no spare parts available Will be replaced with turbo pumpsControl electronics also obsolete and need replacement • RHIC BPM system upgradeTotal capital funding currently planned: $1.9M (FY2010-12) • Existing electronics more than a decade old, will become obsoleteAlso aim for better performance, particularly in turn-by-turn mode 30

31. RHIC OPPIS produces reliably 0.5-1.0 mA polarized H- ion current. Polarization at 200 MeV: P = 80-85%. Beam intensity (ion/pulse) routine operation: Source - 1012 H-/pulse Linac - 5x1011 AGS - 1.5-2.0x1011 RHIC - 1.5x1011/bunch Optically Pumped Polarized H–source at RHIC (A. Zelenski) • Source now being upgraded: • Goals:1. H-ion beam current increase to 10mA(order of magnitude)2. Polarization to 85-90%(~5% increase) • Upgrade components:1. Atomic hydrogen injector (collaboration with BINP Novosibirsk)2. Superconducting solenoid (3 T)3. Beam diagnostics and polarimetry • 29.2 GHz ECR source used for primary proton beam generation • source was originally developed for dc operation • 10x intensity increase was demonstrated in a pulsed operation by using a very • high-brightness Fast Atomic Beam Source instead of the ECR source

32. Capital projects FY2010 – FY2016 • RHIC collimation upgradeTotal capital funding currently planned: $1.0M (FY2013-14) • Have only 1-sided secondary collimators due to space constraints in collimator location (all collimators are located in a straight section in IR8)Secondary collimator at locations far from primary are not working optimally for all lattices (use different lattices for heavy ions and protons)Simulations favor masks in from of triplets in experimental sections • Further capital upgrades • Booster corrector power supply (reliability) • AGS trim quadrupole power supply (performance with high current) • RHIC high precision beam current DCCTs (machine protection with higher proton current after source upgrade) • Siemens Motor-Generator relays (reliability) • AGS multipole corrector power supplies (beam losses at injection) • AGS vertical sextupole power supplies(chromaticity control) • RHIC quench protection(end-of-life electronics) • Cooling tower upgrades(end-of-life replacements) 32

33. Summary • AIP and capital projects are critical to increase performance (luminosity, polarization, flexibility), replace equipment at end of life, and improve operational efficiency (uptime, decrease power and other costs) • Preventive maintenance for single point of failure equipment, replacement at end of life(currently no single-point-of-failure equipment at end of life that could lead to several months of interruption – AGS Main Magnet PS transformer replacement completed in 2009) • Largest power savings have been realized (He refrigerator upgrades in collaboration with TJNAF – total savings 5 MW, 2 MW since 2006) • Main performance upgrades with AIP and capital projects: • Heavy ion luminosity to Lavg 401026cm-2s-1 (= 2x current, = 20x design) with completion of 3D stochastic cooling (Run-12) and 56 MHz SRF (Run-13) • Polarized proton source upgrade (Run-13), and electron lenses in RHIC to mitigate the head-on beam-beam effect (Run-13) 33