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CERN Neutrinos to Gran Sasso: The CNGS Facility at CERN l Edda Gschwendtner, CERN

WIN’11, Cape Town, South Africa, 31 st Jan – 5 th Feb 2011. CERN Neutrinos to Gran Sasso: The CNGS Facility at CERN l Edda Gschwendtner, CERN. Lake Geneva. LHC. CNGS. SPS. CERN. PS. Outline. Introduction to CNGS at CERN Layout and Main Parameters Performance and Operational Experience

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CERN Neutrinos to Gran Sasso: The CNGS Facility at CERN l Edda Gschwendtner, CERN

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  1. WIN’11, Cape Town, South Africa, 31st Jan – 5th Feb 2011 CERN Neutrinos to Gran Sasso:The CNGS Facility at CERNlEdda Gschwendtner, CERN

  2. Lake Geneva LHC CNGS SPS CERN PS Outline • Introduction to CNGS at CERN • Layout and Main Parameters • Performance and Operational Experience • Operating a High Intensity Facility • Summary Edda Gschwendtner, CERN

  3. CERN Gran Sasso Neutrino Introduction • Dm232… governs thenm to nt oscillation • Up to now: only measured by disappearance of muon neutrinos: • Produce muon neutrino beam, measure muon neutrino flux at near detector • Extrapolate muon neutrino flux to a far detector • Measure muon neutrino flux at far detector • Difference is interpreted as oscillation from muon neutrinos to undetected tau neutrinos  K2K, NuMI • CNGS (CERN Neutrinos to Gran Sasso): long base-line appearance experiment: • Produce muon neutrino beam at CERN • Measure tau neutrinos in Gran Sasso, Italy (732km)

  4. Introduction Approved for 22.5·1019 protons on target i.e. 5 years with 4.5·1019 pot/ year(200 days, intensity of 2.4·1013 pot/extraction ) Gran Sasso CERN • Expect ~10 nt events in OPERA measure tau-neutrinos 732km produce muon-neutrinos Physics started in 2008  today: 9.5·1019 pot ~2 nt/year (~1·1017nm/year) ~4·1019 p/year ~2·1019nm/year WIN’11, Cape Town, 31st Jan – 5th Feb 2011 Edda Gschwendtner, CERN

  5. Posc*stcc (arbitrary units) 500m Typical size of a detector at Gran Sasso nm-fluence 1000m 3000m Introduction • Beam optimization: • Intensity: as high as possible • Neutrino energy: matched for nm-ntappearance experiments WIN’11, Cape Town, 31st Jan – 5th Feb 2011 Edda Gschwendtner, CERN

  6. e-, -, h- -  3h- -  How to Detect a Tau Neutrino? •  ntinteraction in the target produces a t lepton. • t lepton: very short lifetime • CNGS: • tau: lorenzboost of ~10: • Tau tracklength: ~1mm • Tau lifetime: 2.9·10-13s • c*lifetime: 87 mm  Identification of tau by the characteristic ‘kink’ on the decay point. • Need high resolution detector to observe the kink • Large mass due to small interaction probability

  7. Neutrino Detectors in Gran Sasso OPERA 1.2 kton emulsion target detector ~146000 lead emulsion bricks ICARUS 600 ton Liquid Argon TPC

  8. CNGS: Classical method to produce neutrino beam CNGS Facility – Layout and Main Parameters  Produce high energy pions and kaons to make neutrinos p + C (interactions) p+,K+ (decay in flight) m+ + nm WIN’11, Cape Town, 31st Jan – 5th Feb 2011 Edda Gschwendtner, CERN

  9. Lake Geneva LHC CNGS SPS CERN PS CERN Accelerator Complex • From SPS: 400 GeV/c • Cycle length: 6 s • 2 Extractions: separated by 50ms • Pulse length: 10.5ms • Beam intensity: 2x 2.4 · 1013 ppp • Beam power: up to 500kW • s ~0.5mm 9 Neu2012, 27-28 Sept. 2010, CERN Edda Gschwendtner, CERN

  10. target magnetic horns decay tunnel hadron absorber muon detector 1 muon detector 2 Edda Gschwendtner, CERN

  11. CNGS Challenges and Design Criteria • High Intensity, High Energy Proton Beam (500kW, 400GeV/c) • Induced radioactivity • In components, shielding, fluids, etc… • Intervention on equipment ‘impossible’ • Remote handling by overhead crane • Replace broken equipment, no repair • Human intervention only after long ‘cooling time’ • Design of equipment: compromise • E.g. horn inner conductor: for neutrino yield: thin tube, for reliability: thick tube • Intense Short Beam Pulses, Small Beam Spot (up to 3.5x1013 per 10.5 ms extraction, < 1 mm spot) • Thermo mechanical shocks by energy deposition (designing target rods, thin windows, etc…)  Proton beam: needs tuning, interlocks! secondary beam area: most challenging zone (target–magnetic horns) WIN’11, Cape Town, 31st Jan – 5th Feb 2011 Edda Gschwendtner, CERN

  12. CNGS Primary Beam Line 840 m total length, 100 m extraction together with LHC Magnet System: • 73 MBG Dipoles • 1.7 T nominal field at 400 GeV/c • 20 Quadrupole Magnets • Nominal gradient 40 T/m • 12 Corrector Magnets Beam Instrumentation: • 23 Beam Position Monitors (Button Electrode BPMs) • recuperated from LEP • Last one is strip-line coupler pick-up operated in air • mechanically coupled to target • 8 Beam profile monitors • Optical transition radiation monitors: 75 mm carbon or 12 mm titanium screens • 2 Beam current transformers • 18 Beam Loss monitors • SPS type N2 filled ionization chambers WIN’11, Cape Town, 31st Jan – 5th Feb 2011 Edda Gschwendtner, CERN

  13. Primary Beam Line Edda Gschwendtner, CERN

  14. CNGS Facility – Layout and Main Parameters Downstream end of the proton beam: last beam position and beam profile monitors BN collimator, d=14mm Be window, t=100mm

  15. TBID 2.7m 43.4m 100m 5m 1095m 18m 5m 67m CNGS Secondary Beam Line • Air cooled graphite target • Multiplicity detector • TBID, ionization chambers • 2 magnetic horns (horn and reflector) • Decay tube • Hadron absorber: • Absorbs 100kW of protons and other hadrons • 2 muon monitor stations: • Muon fluxes and profiles WIN’11, Cape Town, 31st Jan – 5th Feb 2011 Edda Gschwendtner, CERN

  16. CNGS Target CNGS Target: 13 graphite rods each 10 cm long, Ø = 5 mm and/or 4 mm, 2.7 interaction length Note: - target rods thin / interspaced to “let the pions out” - target shall be robust to resist the beam-induced stresses - target is air-cooled (particle energy deposition) WIN’11, Cape Town, 31st Jan – 5th Feb 2011 Edda Gschwendtner, CERN

  17. CNGS Target Target magazine: 1 unit used, 4 in-situ spares 17 WIN’11, Cape Town, 31st Jan – 5th Feb 2011 Edda Gschwendtner, CERN

  18. 150kA/180kA, pulsed 7m long inner conductor 1.8mm thick Designed for 2·107 pulses 1 spare horn (no reflector yet) Design features Water cooling circuit to evacuate 26kW In situ spare, easy switch Remote water connection Remote handling & electrical connections Remote and quick polarity change 0.35 m inner conductor CNGS Horn and Reflector WIN’11, Cape Town, 31st Jan – 5th Feb 2011 Edda Gschwendtner, CERN

  19. Decay Tube • 994m long • steel pipe • 1mbar • 2.45m diameter, t=18mm, surrounded by 50cm concrete • entrance window: 3mm Ti • exit window: 50mm carbon steel, water cooled

  20. 270cm 60cm 11.25cm Muon Monitors • 2 x 41 fixed monitors • (Ionization Chambers) • 2 x 1 movable monitor • LHC type Beam Loss Monitors • Stainless steel cylinder • Al electrodes, 0.5cm separation • N2 gas filling • Muon Intensity: • Up to 8 107 /cm2/10.5ms CNGS Edda Gschwendtner, CERN

  21. CNGS Timeline until Today Civil engineering works for the drains & water evacuation OPERA detector ready Target inspection Additional shielding Reconfiguration of service electronics Repairs & improvements in the horns 2000-2005 Civil Engineering, Installation WIN’11, Cape Town, 31st Jan – 5th Feb 2011 Edda Gschwendtner, CERN

  22. Achieved protons on target: 4.04E19Expected protons on target: 3.83E19 CNGS Run 2010 SPS CNGS efficiency: 81.15%

  23. Nominal (200days): 4.5E19 pot/yr 2010 (218days): 2009 (180 days) : 4.04E19 pot 3.52E19 pot 2008 (133days) : 1.78E19 pot CNGS Physics Run: Comparison of Yearly Integrated Intensity  Total today: 9.5E19 pot WIN’11, Cape Town, 31st Jan – 5th Feb 2011 Edda Gschwendtner, CERN

  24. SPS Efficiencies for CNGS 2008 2009 2010 Integrated efficiency: 60.94% Integrated efficiency: 72.86% Integrated efficiency: 81.15% WIN’11, Cape Town, 31st Jan – 5th Feb 2011 Edda Gschwendtner, CERN

  25. CNGS Operation in 2009/2010 • 2009: 11% more protons on target than expected • 2010: 5% more pot than expected • 57% duty cycle for CNGS with LHC operation and Fixed Target program 1 beam cycle to Fix Target Experiments 5 beam cycles to CNGS WIN’11, Cape Town, 31st Jan – 5th Feb 2011 • Improvements in SPS control system • Allows fast switching between super cycles  gain in time • Improvements in CNGS facility and shutdown work • No additional stops for maintenance Edda Gschwendtner, CERN

  26. CNGS Performance: Beam Intensity Protons on target per extraction for 2010 Typical transmission of the CNGS beam through the SPS cycle ~ 94%. Injection losses ~ 6%. 2E13 pot/extr • Nominal beam intensity: • 2.4E13 p.o.t./extraction • Intensity limits: • Losses in the PS • SPS RF Mean: 1.88E13 pot/extraction 26 WIN’11, Cape Town, 31st Jan – 5th Feb 2011 Edda Gschwendtner, CERN

  27. shielding BPM horn beam target collimator shielding Beam Position on Target • Excellent position stability; ~50 (80) mm horiz (vert) over entire run. • No active position feedback is necessary • 1-2 small steerings/week only RMS =54mm RMS =77mm Vertical beam position [mm] Horizontal beam position [mm] Horizontal and vertical beam position on the last Beam Position Monitor in front of the target WIN’11, Cape Town, 31st Jan – 5th Feb 2011 Edda Gschwendtner, CERN

  28. target magnetic horns decay tunnel hadron absorber muon detector pit 1 muon detector pit 2 Edda Gschwendtner, CERN

  29. Muon Monitors Muon Detector Muon Profiles Pit 2 • Offset of beam vs target at 0.05mm level 270cm • Offset of target vs horn at 0.1mm level • Target table motorized • Horn and reflector tables not 11.25cm Muon Profiles Pit 1 Very sensitive to any beam changes! Online feedback on quality of neutrino beam Centroid =∑(Qi * di) / ∑(Qi) Qi is the number of charges/pot in the i-th detector, di is the position of the i-th detector. 29 Edda Gschwendtner, CERN WIN’11, Cape Town, 31st Jan – 5th Feb 2011

  30. Beam Stability Seen on Muon Monitors • Beam position correlated to beam position on target. • Parallel displacement of primary beam on target Centroid of horizontal profile pit2 ~80mmparallel beam shift  5cm shift of muon profile centroid 30 Edda Gschwendtner, CERN WIN’11, Cape Town, 31st Jan – 5th Feb 2011

  31. 270cm 11.25cm CNGS Polarity Puzzle Muon Detector • Observation of asymmetry in horizontal direction between • Neutrino (focusing of mesons with positive charge) • Anti-neutrino (focusing of mesons with negative charge) 31 WIN’11, Cape Town, 31st Jan – 5th Feb 2011 Edda Gschwendtner, CERN

  32. Anti-neutrino Focusing on negative charge Neutrino Focusing on positive charge Lines: simulated m flux Points: measurements Normalized to max=1 FLUKA simulations, P. Sala et al 2008 CNGS Polarity Puzzle Explanation: Earth magnetic field in 1km long decay tube! • calculate B components in CNGS reference system • Partially shielding of magnetic field due to decay tube steel • Results in shifts of the observed magnitude • Measurements and simulations agree very well (absolute comparison within 5% in first muon pit) 32 WIN’11, Cape Town, 31st Jan – 5th Feb 2011 Edda Gschwendtner, CERN

  33. Horizontal Profile Pit 1 Horizontal Profile Pit 2 Measurements Simulations Vertical Profile Pit 2 Vertical Profile Pit 1 Muon Monitors: Measurements vs. Simulations P. Sala et al, FLUKA simulations 2008 • Data & simulation agree within 5% (~10%) in first (second) muon pit WIN’11, Cape Town, 31st Jan – 5th Feb 2011 Edda Gschwendtner, CERN

  34. Operating a High Intensity Facility WIN’11, Cape Town, 31st Jan – 5th Feb 2011 Edda Gschwendtner, CERN

  35. 2005-07: Magnetic Horns Repair and Improvements • Water leak: •  Failure in one ceramic connector in drainage of the 2nd magnetic horn • Repair work and design improvements in the cooling circuit on both magnetic horns  detailled radiation dose planning, extra shielding. • Damage in one of the flexible strip-line connectors 35 Edda Gschwendtner, CERN WIN’11, Cape Town, 31st Jan – 5th Feb 2011

  36. Ventilation units in the service gallery High-energy (>20MeV) hadrons fluence (h/cm2) for 4.5E19 pots A. Ferrari, L. Sarchiapone et al, FLUKA simulations 2008 2007-2008 CNGS Radiation Issues CNGS: no surface building above CNGS target area  large fraction of electronics in tunnel area Failure in ventilation system installed in the CNGS Service gallery  due to radiation effects in electronics (SEU – Single Event Upsets- due to high energy hadron fluence) 36 Edda Gschwendtner, CERN WIN’11, Cape Town, 31st Jan – 5th Feb 2011

  37. 2006/07 2008++ 106 h/cm2/yr 109 h/cm2/yr 2007-2008 CNGS Radiation Issues Modifications during shutdown 2007/08: • Move most of the electronics out of CNGS tunnel area • Create radiation safe area for electronics which needs to stay in CNGS • Add shielding 53m3 concrete  up to 6m3 thick shielding walls p-beam target chamber p-beam target chamber WIN’11, Cape Town, 31st Jan – 5th Feb 2011 Edda Gschwendtner, CERN 37

  38. 2009-2010 Sump and Ventilation System Modification and Improvements Modification of • Sump system in the CNGS area  avoid contamination of the drain water by tritium produced in the target chamber • Try to remove drain water before reaches the target areas and gets in contact with the air • Construction of two new sumps and piping work • Ventilation system configuration and operation • Keep target chamber TCC4 under pressure wrt the other areas • Do not propagate the tritiated air into other areas and being in contact with the drain water 2 new small sumps (1m3), pump out water immediately WIN’11, Cape Town, 31st Jan – 5th Feb 2011

  39. CNGS 2011 2011 Injector Schedule Physics run starts on 18th March 2011 End of physics: 21st November 2011 If all goes well, as in 2010, we expect more than 4.5E19 protons on target in 2011! WIN’11, Cape Town, 31st Jan – 5th Feb 2011 Edda Gschwendtner, CERN

  40. Summary • All issues at CNGS so far come from ‘peripheral equipment’ and general services • start-up issues of CNGS have been overcome • BUT: Operating and maintaining a high-intensity facility is very challenging • Tritium issue, fatigue, corrosion,… • Beam performance since start of physics run in 2008 CNGS is very good • Expect to have 14 E19 pot by end of 2011 • CERN will continue with physics running in 2012. • 1 year stop in 2013 WIN’11, Cape Town, 31st Jan – 5th Feb 2011 Edda Gschwendtner, CERN

  41. Additional slides WIN’11, Cape Town, 31st Jan – 5th Feb 2011 Edda Gschwendtner, CERN

  42. CNGS Primary Beam • Extraction interlock modified to accommodate the simultaneous operation of LHC and CNGS • Good performance, no incidents • No extraction and transfer line losses • Trajectory tolerance: 4mm, last monitors to +/-2mm and +/- 0.5mm (last 2 monitors) • Largest excursion just exceed 2mm Primary proton beam trajectory Horizontal plane 2mm target Extracted SPS beam 840m 2mm Vertical plane WIN’11, Cape Town, 31st Jan – 5th Feb 2011 Edda Gschwendtner, CERN

  43. Beam Stability Seen on Muon Monitors RMS =3.02cm RMS =2.6cm Horizontal centroid [mm] Vertical centroid [mm] • Position stability of muon beam in pit 2 is ~2-3cm rms 43 Edda Gschwendtner, CERN WIN’11, Cape Town, 31st Jan – 5th Feb 2011

  44. Continuous Surveillance The CNGS facility is well monitored.  Redundancy is important! 22E13 60° 11° 20° Protons on Target/Extraction Temp downstream Horn Horn water conductivity Horn cooling water temperature 13° 45° 2° 44 Edda Gschwendtner, CERN WIN’11, Cape Town, 31st Jan – 5th Feb 2011

  45. Working hypothesis for RP calculations CNGS working hypothesis Design limit for target, horn, kicker, instrumentation Design limit for horn, shielding, decay tube, hadron stop Intensity Limitations from the CNGS Facility  Horn designed for 2E7 pulses, today we have 1.4E7 pulses  spare horn  Intensity upgrade from the injectors are being now evaluated WIN’11, Cape Town, 31st Jan – 5th Feb 2011

  46. Five beamlets separated by 1 PS turn Multi-Turn-Extraction Courtesy MTE project - M. Giovannozzi et. al. • Novel extraction scheme from PS to SPS: • Beam is separated in the transverse phase space using • Nonlinear magnetic elements (sextupoles and octupoles) to create stable islands. • Slow (adiabatic) tune-variation to cross an appropriate resonance. • Beneficial effects: • No mechanical device to slice the beam losses are reduced • The phase space matching is improved • The beamlets have the same emittance and optical parameters. MTE extracted beam in 2009 during Machine Development periods 2010: Started with MTE, then classical extraction Result of the first extraction test in the PS extraction line (TT2) with one bunch. Evolution of the horizontal beam distribution during the splitting. WIN’11, Cape Town, 31st Jan – 5th Feb 2011 Edda Gschwendtner, CERN

  47. Examples: effect onντcc events horn off axis by 6mm < 3% reflector off axis by 30mm < 3% proton beam on target < 3% off axis by 1mm CNGS facility misaligned < 3% by 0.5mrad (beam 360m off) CNGS Performance - Reminder WIN’11, Cape Town, 31st Jan – 5th Feb 2011 Edda Gschwendtner, CERN

  48. CNGS Proton Beam Parameters Dedicated mode: 500kW beam power 48 WIN’11, Cape Town, 31st Jan – 5th Feb 2011 Edda Gschwendtner, CERN

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