WIN’11 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

WIN’11 WIN’11, Cape Town, 31 st Jan – 5 th Feb 2011 Edda Gschwendtner, CERN 2 Outline Introduction to CNGS at CERN Layout and Main Parameters Performance and Operational Experience Operating a High Intensity Facility Summary CERN PS SPS LHC CNGS Lake Geneva

WIN’11 Neutrino Introduction   m 2 32 … governs the  to  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) CERN Gran Sasso 3

WIN’11 Edda Gschwendtner, CERN 4 Introduction WIN’11, Cape Town, 31 st Jan – 5 th Feb 2011 produce muon-neutrinos measure tau-neutrinos CERN Gran Sasso 732km ~4·10 19 p/year ~2·10 19  /year ~2  /year ( ~1·10 17  /year) Physics started in 2008  today: 9.5 ·10 19 pot  Expect ~10  events in OPERA Approved for 22.5·10 19 protons on target i.e. 5 years with 4.5·10 19 pot/ year (200 days, intensity of 2.4·10 13 pot/extraction )

WIN’11 Edda Gschwendtner, CERN 5 Introduction P osc *   cc (arbitrary units)  -fluence WIN’11, Cape Town, 31 st Jan – 5 th Feb 2011 Typical size of a detector at Gran Sasso 500m 1000m 3000m Beam optimization:  Intensity: as high as possible  Neutrino energy: matched for  -  appearance experiments

WIN’11 How to Detect a Tau Neutrino?   interaction in the target produces a  lepton.   lepton: very short lifetime   e -,  , h    3h   Identification of tau by the characteristic ‘kink’ on the decay point. Tau lifetime: 2.9· s  c*lifetime: 87  m  Need high resolution detector to observe the kink  Large mass due to small interaction probability CNGS: tau: lorenzboost of ~10:  Tau tracklength: ~1mm 6

WIN’11 Neutrino Detectors in Gran Sasso ICARUS 600 ton Liquid Argon TPC OPERA 1.2 kton emulsion target detector ~ lead emulsion bricks 7

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

WIN’11 Neu2012, Sept. 2010, CERN Edda Gschwendtner, CERN 9 CERN PS SPS LHC CNGS Lake Geneva CERN Accelerator Complex From SPS: 400 GeV/c Cycle length: 6 s 2 Extractions: separated by 50ms Pulse length: 10.5  s Beam intensity: 2x 2.4 · ppp Beam power: up to 500kW  mm

WIN’11 Neu2012, Sept. 2010, CERN Edda Gschwendtner, CERN 10 target magnetic horns decay tunnel hadron absorber muon detector 1 muon detector 2

WIN’11 Edda Gschwendtner, CERN 11  secondary beam area: most challenging zone (target–magnetic horns) 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 3.5x10 13 per 10.5  s extraction, < 1 mm spot) –Thermo mechanical shocks by energy deposition (designing target rods, thin windows, etc…)  Proton beam: needs tuning, interlocks! WIN’11, Cape Town, 31 st Jan – 5 th Feb 2011

WIN’11 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  m carbon or 12  m titanium screens 2 Beam current transformers 18 Beam Loss monitors –SPS type N 2 filled ionization chambers WIN’11, Cape Town, 31 st Jan – 5 th Feb 2011

WIN’11 Neu2012, Sept. 2010, CERN Edda Gschwendtner, CERN 13 Primary Beam Line

WIN’11 Downstream end of the proton beam: last beam position and beam profile monitors BN collimator, d=14mm Be window, t=100  m CNGS Facility – Layout and Main Parameters

WIN’11 Edda Gschwendtner, CERN m 100m 1095m18m5m 67m 2.7m TBID 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 CNGS Secondary Beam Line WIN’11, Cape Town, 31 st Jan – 5 th Feb 2011

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

WIN’11 Edda Gschwendtner, CERN 18 CNGS Horn and Reflector 150kA/180kA, pulsed 7m long inner conductor 1.8mm thick Designed for 2·10 7 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 WIN’11, Cape Town, 31 st Jan – 5 th Feb 2011

WIN’11 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

WIN’11 Neu2012, Sept. 2010, CERN Edda Gschwendtner, CERN 20 60cm 270cm 11.25cm 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 N 2 gas filling CNGS Muon Intensity: –Up to /cm 2 /10.5  s Muon Monitors

WIN’11 Edda Gschwendtner, CERN Commissioning Leak in the reflector cooling circuit, damaged stripline cable 2007 Beam commissioning with high intensity Radiation effects in ventilation system electronics 2008 Physics run Damaged target magazine rotation bearings 2009 Physics run MTE tests Tritium issue 2010 Physics run MTE tests Tritium issue CNGS Timeline until Today Repairs & improvements in the horns Additional shielding Reconfiguration of service electronics Target inspection Civil engineering works for the drains & water evacuation Civil Engineering, Installation WIN’11, Cape Town, 31 st Jan – 5 th Feb 2011 OPERA detector ready

WIN’11 CNGS Run 2010 Achieved protons on target: 4.04E19 Expected protons on target: 3.83E19 SPS CNGS efficiency: 81.15% 22

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

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

WIN’11 Edda Gschwendtner, CERN 25 CNGS Operation in 2009/2010 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 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 5 beam cycles to CNGS 1 beam cycle to Fix Target Experiments WIN’11, Cape Town, 31 st Jan – 5 th Feb 2011

WIN’11 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%. Nominal beam intensity: 2.4E13 p.o.t./extraction Intensity limits: Losses in the PS SPS RF WIN’11, Cape Town, 31 st Jan – 5 th Feb 2011 Mean: 1.88E13 pot/extraction 2E13 pot/extr

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

WIN’11 Neu2012, Sept. 2010, CERN Edda Gschwendtner, CERN 28 target magnetic horns decay tunnel hadron absorber muon detector pit 1 muon detector pit 2

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

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

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

WIN’11 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) Lines: simulated m flux Points: measurements Normalized to max=1 Neutrino Focusing on positive charge Anti-neutrino Focusing on negative charge FLUKA simulations, P. Sala et al 2008 Edda Gschwendtner, CERN 32 WIN’11, Cape Town, 31 st Jan – 5 th Feb 2011

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

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

WIN’ : Magnetic Horns Repair and Improvements Water leak:  Failure in one ceramic connector in drainage of the 2 nd 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 WIN’11, Cape Town, 31 st Jan – 5 th Feb 2011Edda Gschwendtner, CERN 35

WIN’11 Edda Gschwendtner, CERN 36 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) CNGS: no surface building above CNGS target area  large fraction of electronics in tunnel area High-energy (>20MeV) hadrons fluence (h/cm 2 ) for 4.5E19 pots A. Ferrari, L. Sarchiapone et al, FLUKA simulations 2008 Ventilation units in the service gallery WIN’11, Cape Town, 31 st Jan – 5 th Feb CNGS Radiation Issues

WIN’11 11th ICATPP Villa Olmo, Como 5-9 Oct Edda Gschwendtner, CERN CNGS Radiation Issues 10 6 h/cm 2 /yr 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  53m 3 concrete  up to 6m 3 thick shielding walls 2006/ h/cm 2 /yr p-beam target chamber p-beam target chamber WIN’11, Cape Town, 31 st Jan – 5 th Feb

WIN’ 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 (1m 3 ), pump out water immediately WIN’11, Cape Town, 31 st Jan – 5 th Feb 2011

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

WIN’11 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 –1 year stop in 2013 WIN’11, Cape Town, 31 st Jan – 5 th Feb 2011

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

WIN’11 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 Horizontal plane Vertical plane 2mm Primary proton beam trajectory 840m target Extracted SPS beam WIN’11, Cape Town, 31 st Jan – 5 th Feb 2011

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

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

WIN’11 Intensity Limitations from the CNGS Facility Intensity per PS batch # PS batches Int. per SPS cycle 200 days, 100% efficiency, no sharing 200 days, 55% efficiency, no sharing 200 days, 55% efficiency, 60% CNGS sharing [prot./6s cycle] [pot/year] 2.4× Nominal CNGS24.8× × × × × Ultimate CNGS27.0×10 13 (2.02×10 20 )(1.11×10 20 )(6.65×10 19 ) Design limit for target, horn, kicker, instrumentation CNGS working hypothesis Working hypothesis for RP calculations Design limit for horn, shielding, decay tube, hadron stop  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, 31 st Jan – 5 th Feb 2011

WIN’11 Edda Gschwendtner, CERN 46 Multi-Turn-Extraction 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. Five beamlets separated by 1 PS turn Result of the first extraction test in the PS extraction line (TT2) with one bunch. Courtesy MTE project - M. Giovannozzi et. al. Evolution of the horizontal beam distribution during the splitting. MTE extracted beam in 2009 during Machine Development periods 2010: Started with MTE, then classical extraction WIN’11, Cape Town, 31 st Jan – 5 th Feb 2011

WIN’11 Edda Gschwendtner, CERN 47 CNGS Performance - Reminder Examples:effect on ν τ cc 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) WIN’11, Cape Town, 31 st Jan – 5 th Feb 2011

WIN’11 Edda Gschwendtner, CERN 48 Beam parametersNominal CNGS beam Nominal energy [GeV] 400 Normalized emittance [  m ] H=12 V=7 Emittance [  m ] H=0.028 V= Momentum spread  p/p 0.07 % +/- 20% # extractions per cycle 2 separated by 50 ms Batch length [  s ] 10.5 # of bunches per pulse 2100 Intensity per extraction Bunch length [ns] ( 4  ) 2 Bunch spacing [ns] 5 Beta at focus [m] hor.: 10 ; vert.: 20 Beam sizes at 400 GeV [mm] 0.5 mm Beam divergence [mrad] hor.: 0.05; vert.: 0.03 CNGS Proton Beam Parameters Dedicated mode: 500kW beam power WIN’11, Cape Town, 31 st Jan – 5 th Feb 2011