T2K beam line and near detectors Antonin Vacheret for the T2K collaboration Reptiles ( M . C . Escher ) 1
Tokai to Kamioka ( T2K ) 12 countries, 62 institutions, ~ 350 people Far detector : Super Kamiokande ν beam : J - PARC facility sin 2 2 θ 13 Sensitivity 20 % ➡ 2009 Phase I : θ 13 , θ 23 , Δ m 223 10 % 10 - 1 5 % • J-PARC : 0.75 MW 30 GeV 3 σ • SK-III : 22.5 kT FV, full PMT coverage 10 - 2 90 % C . L . ➡ 2015 Phase II : θ 13 , δ CP ? • 10 - 3 J-PARC : 4MW 50 GeV Phase I Phase II • HyperK : 1 MT scale 1 10 100 Exposure ( 22 . 54kTxyear ) Antonin Vacheret, Imperial College London NuInt07, May 30, June 3 2007 Fermilab 2
T2K measurements SuperK selected 1 ring e - LIKE evts Δ m 2 = 2 . 5x10 - 3 eV 2 sin 2 2 θ 13 sin 2 2 θ 13 = 0 . 05 0 . 35 - 0 . 85 GeV : 2 . 5º peak energy ~ 650 MeV beam nue ~ 0 . 5 % Signal : 109 evts Bkg . : 26 . 6 evts ν μ BKG beam ν e SuperK selected 1 ring μ - LIKE evts ➡ Appearance sin 2 2 θ 13 > 0 . 01 sin 2 2 θ 23 osc . max . ➡ Disappearance δ (sin 2 2 θ 23 ) ≈ 0 . 01 ∆ m 2 23 δ (∆ m 2 23 ) < 10 − 4 e V 2 non - QE Bkg . Antonin Vacheret, Imperial College London NuInt07, May 30, June 3 2007 Fermilab 3
T2K Systematics ➡ To be measured before oscillation • Beam flux • Beam ν e contamination • ν μ non-QE background ➡ Near detector tasks : • SuperK ν e background < 10% • ν μ event normalisation < 5% • Energy scale < 2% • Beam linear distortion < 20% • Width < 10% • non-QE/CCQE at 5-10% Antonin Vacheret, Imperial College London NuInt07, May 30, June 3 2007 Fermilab 4
Disappearance background ! ! Antonin Vacheret, Imperial College London NuInt07, May 30, June 3 2007 Fermilab 5
J - PARC ARC Superconducting Magnets Kicker region 50 GeV Main Ring 3 GeV Rapid ➡ description + pictures Cycling Synchrotron LINAC 400 MeV Nov 2006 Antonin Vacheret, Imperial College London NuInt07, May 30, June 3 2007 Fermilab 6
J - PARC Neutrino beamline Extraction point ARC Final Focusing Decay pipe 0º on - axis Target Station ~ 110 m 2 . 5º o fg - axis ( diag ) 280 m Beam diagnostics : Position 20 Profile 19 Intensity 4 Antonin Vacheret, Imperial College London NuInt07, May 30, June 3 2007 Fermilab 7
J - PARC Neutrino beamline Beam dump Muon monitors Extraction point Graphite Blocks a m m B B e e a ~3 m ARC ~2 m Moving stage ~1 m 2 km Gas tube Signal/HV line detectors Final Focusing ( Proposed ) Decay pipe 0º on - axis Target Station ~ 110 m 2 . 5º o fg - axis ( diag ) 280 m Beam diagnostics : ND280 Position 20 detectors Profile 19 complex Intensity 4 Antonin Vacheret, Imperial College London NuInt07, May 30, June 3 2007 Fermilab 8
Tracking plane assembly 280m On - Axis : Steel plate INGRID ν ➡ Monitor beam direction, intensity and mean Support structure energy ➡ Beam coverage 10x10 m 2 ➡ 16 Modules • Fe/Scint (5x1x100cm bar) ➡ O fg - axis angle measurement accuracy : 1mrad (< 15MeV ) • 10k events per day ➡ Shift resolution 3cm -> 3mm o fg target 1mm at target Antonin Vacheret, Imperial College London NuInt07, May 30, June 3 2007 Fermilab 9
ND280 O fg - Axis Detector ➡ 2 - 2 . 5º O fg - axis ➡ Re - use UA1 Magnet • Uniform dipole field B = 0.2 T ➡ Target detectors installed in Basket ~ 8 m ND280 Pit Neutron shield Basket 16m SK ND280 OA SK ~ 3 . 5 m SK direction INGRID FGD MRD 36m 2 ° ν beam 5m BEAM 3 ° ~14m Antonin Vacheret, Imperial College London NuInt07, May 30, June 3 2007 Fermilab 10
ND280 O fg - Axis : P0D region Pi0 detector(P0D) P0D Up/Central Calorimeters Target Modules 40 X-Y Pb/plastic planes 30 cm thick 5.7X0 40% H 2 0 Passive X-Y Pb/plastic thicker planes 6t fiducial mass gamma catcher 10560 total channels active veto Minerva bar ν Water bag in gasketed container Surrounding Calorimeter (PECAL) Coarse Pb/Plastic (4x1cm bar) Scintillator 10cm thick ~5.0X0 Planes layout γ catcher MIP tagging ~2k Channels Antonin Vacheret, Imperial College London NuInt07, May 30, June 3 2007 Fermilab 11
P0D : NC π 0 measurement ➡ Dedicated to appearance backgrounds • 1.7x10 4 NC-Res1 π 0 events in H 2 0 γ 1 target per year • ~ 6000 π 0 reconstructed γ 2 • Water in/out periods : C/H 2 0 differences • Inclusive NC/CC production • Beam ν e Antonin Vacheret, Imperial College London NuInt07, May 30, June 3 2007 Fermilab 12
ND280 O fg - Axis : Tracker region Side muon ranging 2 Fine Grained detector (SMRD) 2x1.3t target 87x17x1cm planes detectors (FGD) instrumenting air gaps FGD1(C): X-Y plastic 4 slabs per planes FGD2(H 2 0): X-Y plastic ν μ ranging +passive water target active veto 8k channels cosmic trigger 10 mm Tracker Calorimeter X-Y fine grained Pb/Plastic (4x1cm bar) Eres ~7.5%/ √ E 20K channels 3 TPC modules Micromegas modules Position resolution < 0.8 mm 36x34 cm 2 Mom resolution to 1GeV <7-8% MM modules Antonin Vacheret, Imperial College London NuInt07, May 30, June 3 2007 Fermilab 13
Simulated Events TRACKER SIDE VIEW ( BENDING PLANE ) Tracker ECAL : B EM shower pointing + energy resolution + TPC : PID sign + momentum + dE / dX TRACKER TOP VIEW ν e event in FGD1 FGD : dEdx, proton recoil, C / H 2 O subtraction Antonin Vacheret, Imperial College London NuInt07, May 30, June 3 2007 Fermilab 14
FGD - TPC - Tracker ECal - SMRD ➡ O fg - axis beam flux and energy spectrum measurement • Select pure QE events ➡ Background measurements ( CC - 1 π + , NC - 1 π 0 ) • Select/ reject CC-1 π events ➡ Cross - section studies Tracker ECAL TPC FGD dE / dX vs Momentum Δ p / p < 0 . 1 @ 1 GeV Δ E / E = 7 . 5 %/ √ E p π Antonin Vacheret, Imperial College London NuInt07, May 30, June 3 2007 Fermilab 15
NC - 1 π 0 : FGD - Tracker ECal TRACKER SIDE VIEW ➡ Exclusive NC - 1 π 0 FGD1 FGD2 ➡ Statistically limited • ~ 800 NC- π 0 evts/year(10 21 POT) γ 1 ➡ use Tracker ECAL fine shower sampling and γ 2 pointing capability to B reconstruct π 0 decay Tight selection cuts Antonin Vacheret, Imperial College London NuInt07, May 30, June 3 2007 Fermilab 16
Novel type of photosensor : Geiger Mode multi - pixels APD ND280 Scintillator Detectors 1mm 2 Constraints : ~40um ~50um - Magnetic Field MPPC - Very tight space constraints MRS-APD - Low light yield at end of WLS fibre � Q pixel Signal = - High number of channels i - Detector operation 5 years i Photo-electron resolution + dynamic range combined in 1 sensor GM-APDs - Insensitive to magnetic field, tested to 4T 1pe - Small (active area ~1mm 2 ) - Bias voltage 50V 2pe - Photon detection efficiency >20% at 500nm - Gain G~ 5x10 5 3pe - Low power consumption - Dark count rate ~0.5MHz/mm 2 at 25ºC - Longevity OK Antonin Vacheret, Imperial College London NuInt07, May 30, June 3 2007 Fermilab 17
Near / Far extrapolation Example of K2K F/N method : T2K requirement GeV ➡ Finite acceptance at ND280 • Extrapolation very sensitive to energy scale and flux shape ➡ Need to reduce systematic errors in hadron production distributions • No data available in the 30-50 GeV region Antonin Vacheret, Imperial College London NuInt07, May 30, June 3 2007 Fermilab 18
NA61 at CERN 15 countries, 25 institutions, ~ 100 Physicists ➡ Physics program • Quark-Gluon Plasma transition • Measure hadron production (p+C reactions in 30-50GeV range) ➡ Re - use NA49 set - up + minor upgrades ➡ 3 targets : thin, thick and copy of T2K • Pions and Kaons productions • Study primary interactions ➡ Fully approved in April 2007 ! ➡ Data taking start at end of September 2007 Antonin Vacheret, Imperial College London NuInt07, May 30, June 3 2007 Fermilab 19
2KM Proposal MRD Water LAr + H 2 0 Cherenkov target ➡ Strengthen prediction of far detector flux through measurement ( ~2 km away ) using : Φ SK / Φ 2KM • Almost same beam flux as far detector • Same target material • Same detector technology and reconstruction analysis ➡ Check ND280 + NA61 prediction before oscillation ➡ Combine ND280 + 2kM measurements SK BKG • Reduce further the systematic errors 2KM prediction • Understand better the ν e backgrounds Antonin Vacheret, Imperial College London NuInt07, May 30, June 3 2007 Fermilab 20
T2K Schedule ➡ Beam line construction started Apr . 2004 ➡ ND280 pit construction start Jul . 2007 ➡ UA1 magnet installation Apr . 2008 ➡ Completion of ND280 building Mar . 2009 ➡ Neutrino beam line commissioning Apr . 2009 ➡ T2K data taking starts Apr . 2009 ➡ ND280 Commissioning Oct . 2009 ➡ ND280 Data taking Nov . 2009 ... Antonin Vacheret, Imperial College London NuInt07, May 30, June 3 2007 Fermilab 21
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