The Calorimeter of the T2K-ND280 Detector System

1. The Calorimeter of the T2K-ND280 Detector System AthansHatzikoutelis Lancaster University UK June 24, 2009

2. Outline • The T2K (Tokai to Kamioka) experiment. • The ND280 (Near Detector) Project. • The Electro-magnetic tracking calorimeter. • The current sub-systems • The future. 2 A. Hatzikoutelis , T2K Collaboration

3. The T2K experiment • Tokai-to-Kamioka neutrino oscillation experiment appearance of electron neutrinos in a muon neutrino beam • 30 GeV protons of 750 kWproduced at the new JPARC complex • integrated exposure of 100 kW*1e7 s starting in April 2009. 3 A. Hatzikoutelis , T2K Collaboration

4. Key measurement in ν physics • A positive measurement of sin2(2θ13) > 0.01 • possibility to study CP violation in the lepton sector • the determination of the neutrino mass • hierarchy with upgraded conventional super-beams • No evidence for sin2(2θ13) • trigger intense discussions on how to best proceed below sin2(2θ13) ≈ 0.01 4 A. Hatzikoutelis , T2K Collaboration

5. The Near detector • Understand the neutrino beam. • On – Axis Detector • Beam monitoring • Beam direction • Off – Axis Detector • Understand the neutrino beam to SK. • Beam Flux • Beam ne Contamination • Background Processes • Cross Sections neutrino beam On-axis Detector INGRID 5 A. Hatzikoutelis , T2K Collaboration

6. Off-axis technique J-PARC  n p Off-axis Near Detector Far Detector (SK) Target 2.5º • Intense & narrow-band beam • 2.5º off-axis • Energy peak ~ 0.7 GeV • Statistics at Far Detector • ~1600 nm CC int./22.5kt/year (0.75 MW beam, no oscillation ) • Purity of nm beam • Beam ne contamination ~0.4% at nm peak energy • Running time: 5 years @ 750 kW proton beam intensity m &Horns On-axis detector Decay pipe Muon monitor Near Detector 0m 120m 280m 295 km Oscillation Prob. @ Dm2 = 3.010-3 n energy spectrum (Flux X-section) OA0 OA2 OA2.5 OA3 6 A. Hatzikoutelis , T2K Collaboration

7. Off-axis detector • Arrays housed in UA1 magnet with 0.2 T. 280 m downstream of the target operators 7 A. Hatzikoutelis , T2K Collaboration

8. Five detector arrays • Pi-zero Detector (PØD) • measures NC p0 interactions. • Tracking System: • fine-grained detector (FGD) • time projection chambers (TPC) • Targets of 16O and 12C for the v. • Measure CC interactions. • Electromagnetic calorimeter (ECAL). • Total energy and particle id. • Side muon-range detector (SMRD). • Cosmics veto. • Side-going muon id. 8 A. Hatzikoutelis , T2K Collaboration

9. P0D • Active Scintillator Neutrino Target • water + scintillator • NC π° • reconstruction efficiency ~30% • signal to noise ~2.3 • E&M resolution ~15%/√E (GeV) • Is build and being installed • Primary Measure Goals • NC and CC π° production ν Simulated 440 MeV/c π˚ Distance in P0D 9 A. Hatzikoutelis , T2K Collaboration

10. 2.5 m 2.5 m TPC FGD tracker detectors • 3D tracking for pattern recognition. • Measure momenta and charge of charged particles • Distinguish electrons and muons/pions and protons. • B=0.2 T . • Micromegas technology was selected to provide the gas amplification for readout νμ 10 A. Hatzikoutelis , T2K Collaboration

11. Down-stream Calorimeter • After the tracker detectors. • Perpendicular to the v beam. v beam DsEcal 11 A. Hatzikoutelis , T2K Collaboration

12. Calorimeter 4x2 m2 x 0.5 m • Energy resolution from simulations. • Dominated by sampling fluctuations. • Est: 7.5% √E(GeV). • up to 5 GeV. • Good electron pion separation. • 90% elec efficiency with • 95% pion rejection. Barrel EcaL P0D Ecal FGD & TPC trackers DsEcal 2x2m2 x 0.5 m P0D v beam P0D Ecal Barrel Ecal 12 A. Hatzikoutelis , T2K Collaboration

13. Calorimeter : General Design • Multiple layers of scintillator lead. • Extruded plastic from Fermi National Labs. • Similar to K2K-Scibar and Minos. • X-Y orientation change between even and odd numbered layers. • One Y11 Kuraray fibre (WLS) per bar. • Double- and single-ended photo-sensor readout per fibre. • MPPC from Hamamatsu. • 1st large deployment. Plastic scintillator Bar: 4cmx1cmx200cm Centre hole :1mmx2mm elliptical 13 A. Hatzikoutelis , T2K Collaboration

14. Light Attenuation • Dominated by the properties of the fibers. • Tested with cosmics and 137Cs as function of distance from the end. • Light yield ~ 12.5pe/mip (with PMT) • The solid curves are double exponentials of attenuation lengths. • Short=0.52m, • Long= 4.2m • Each channel of the calorimeter • Individual check (qual. assur.). • Labeled and logged. • Construction and calibration database. The errors in distance-axis come from the size of the trigger-scintillator pads. Radiation source activating a scintillator • MPPC readout : • integral of current output 14 A. Hatzikoutelis , T2K Collaboration

15. The P0D Ecal The Barrel Ecal • Surrounds the P0D array. • Detects escaping photons, muons. • 6 scintillator bar layers. • 4 lead sheets 5mm. • 4 X0 radiation lengths. • Single-ended readout. • Low requirement for energy and spatial resolution. • Effective depth. • Surrounds the tracking detectors. • Measures particles that leave the volume. • Separated in 6 parts to move with the opening of the magnet. • 32 scintillator bar layers thick. • 31 lead sheets x 1.75mm • 10.5 X0 radiation lengths. • 18,000 double- and single-ended readout. • Good reconstruction efficiency for pions. • Good spatial resolution for photons. 15 A. Hatzikoutelis , T2K Collaboration

16. ECAL construction(DsEcal example) • The first part of the Ecal to be constructed. • Area 2 x 2 m 2 • 34 scint-lead layers, 1.75mm lead sheets. • 11 X0 radiation lengths. • 3400 double-ended readout. • Kuraray Y11, straight canes 16 A. Hatzikoutelis , T2K Collaboration

17. Photo sensors • MultiPixel-PhotoCounters. • 100~1600 small avalanche photo diodes( APD ) • 1.3mm2 sensitive region. • Magnetically unaffected. • New device, first large scale deployment. • 50,000 in ND280. • 23,000 for the Ecal. • Each individually checked and labelled. Sensitive region of MPPC 400pixel type 50 micron 2 50 micron 2 17 A. Hatzikoutelis , T2K Collaboration

18. Basic performance of MPPC MPPC raw signal • Twice the PDE (efficiency) than PMT’s. • We can observe 1p.e, 2p.e, etc, signal peaks. • High noise rate , ~80kHz. prototyped and characterized at Kyoto univ. 1pe 2pe 3pe 4pe? Pedestal 1pe Digitized MPPC signal 2pe 3pe 18 A. Hatzikoutelis , T2K Collaboration

19. Light Injection System Top view Side view • Monitoring MPPC gain and fibre integrity. • Positioned in the cavity between the detector frames and the bulkhead. • Specifically tuned driver boards. • Illuminate uniformly the exposed fibres. Drive boards Layer 001 WLS fiber LED strips Layer 001 Layer 001 19 A. Hatzikoutelis , T2K Collaboration

20. http://www.hep.lancs.ac.uk/~scanner/T2KPIX/pix070708/SS850481.AVIhttp://www.hep.lancs.ac.uk/~scanner/T2KPIX/pix070708/SS850482.AVIhttp://www.hep.lancs.ac.uk/~scanner/T2KPIX/pix070708/SS850481.AVIhttp://www.hep.lancs.ac.uk/~scanner/T2KPIX/pix070708/SS850482.AVI 137Cs Module Scanner Y x • Programmable motor control. • Sliders give the arm motion in two dimensions. • Arm places the source 14mm from top of lead sheet of layer. • 3mCu 137Cs source. • Run along each bar. • Define the detector limits. Scan direction Quick return 20 A. Hatzikoutelis , T2K Collaboration

21. Front –End Readout • 4 Trip-t chips. • Ethernet 1MB comm. • 64 channels per front-end board. • 2 ADC and 1 TDC output per channel. • All power and cooling on board. 21 A. Hatzikoutelis , T2K Collaboration

22. Commissioning cosmics RAL ISIS Hall • Hardware Commissioning • Commissioning of the data acquisition and light injection systems. • Tuning the cosmic trigger. • Software Commissioning • Indicative spectrum of cosmics • Bar (arbcoice) at the center of the calorimeter • over 16 hours at 55Hz Low energy noise from the MPPC m.i.p. signal distribution. Mean 25 p.e. ADC chn (arb units) 22 A. Hatzikoutelis , T2K Collaboration

23. Hit density distribution (Hit-map) Top view cosmic • Tuning the cosmic trigger. • Calibration of all channels and pixels with cosmic muons. • Self-triggered on the front half. x Front cosmic Side view Front, cosmic Front 40000 cosmic triggers sample 23 A. Hatzikoutelis , T2K Collaboration

24. Tuning Reconstruction& PID. First physics analysis using observed data Calibration with cosmics Iso-view Left TOP Event dispaly of cosmic muon (2-4MeV) The bars that are hit are clearly lighted up with Signal clearly above the MPPC noise. 24 A. Hatzikoutelis , T2K Collaboration

25. Test-beam @ CERN CERN , PS, T9, pions,muons,electrons • Calibration with test-beam. • CERN T9 beam-line at East area Hall. • Library of clean data profiles at energies 0.4 to 4GeV. • hadronic and • electromagnetic shower Beam composition (%) electrons pions prelim. Beam energy (GeV) 25 A. Hatzikoutelis , T2K Collaboration

26. ECAL PID • Particle Identification algorithm • uses an artificial neural network. • discriminate between electromagnetic showers, hadronic showers and tracks. muon + pion, 3.2GeV shower 3d event view collected on test-beam run of May 7 ‘09 26 A. Hatzikoutelis , T2K Collaboration

27. particle id with ECAL(preliminary) Simulated medium energy electron shower. Event display of beam electrons Medium energy Beam e side view 600MeV e Top view 600MeV e 27 A. Hatzikoutelis , T2K Collaboration

28. Tracks PID (preliminary) • Tracks come from mips. • Relatively small spread in charge deposits. • narrow, • long shape • uniform charge deposition. Simulated muon 940 MeV Beam muon 800MeV 28 A. Hatzikoutelis , T2K Collaboration

29. Pions ID in ECAL (prelim) Simulated hadronic showers Charged beam pions 1GeV Top view 3GeV Side view 29 A. Hatzikoutelis , T2K Collaboration

30. Time cuts (prelim) Top view Clearly a pion • Charged beam 2.2GeV particles coincident in the detector. Side view Clearly a stopped muon Side view 30 A. Hatzikoutelis , T2K Collaboration

31. 31 A. Hatzikoutelis , T2K Collaboration

32. Conclusions 32 • The T2K experiment will measure • How small is θ13 ? • Does θ23 represent maximal mixing? • Can we search for CP violation in the lepton sector? • ND280 off-axis detector will aim to address • energy spectrum, backgrounds, neutrino interactions • The Electromagnetic calorimeter will assist the measurements by helping id the beam profile. • The first part of the Ecal is ready for calibration. • The rest of the Ecal is on target for construction. A. Hatzikoutelis , T2K Collaboration

33. February 2006 J-PARC accelerator 50 GeV Synchrotron (MR) Neutrino beam line Neutrino beam (to Super-K) 3 GeV Synchrotron (RCS) LINAC 33 A. Hatzikoutelis , T2K Collaboration

34. Sensitivity sin2(2θ13) < 0.01 (90%C.L.) after 5 years at nominal intensity. A plan to upgrade the power to 1.6 MW has been presented in the KEK roadmap, opening the path towards an upgraded Asian long-baseline neutrino The T2K beamlineis designed for MW power and has successfully started commissioning in April 2009 and the first • Expecetd sensitivity • sin2(2θ13) < 0.01 (90%C.L.) • after 5 years at nominal intensity. • • T2K uses high intensity 30 GeV protons produced at the new JPARC complex. • measure nm→ντdisappearance, • Atmospheric parameter q23 and Dm223(~Dm213) • search for nm ne appearance, i.e. non-zero q13 34 A. Hatzikoutelis , T2K Collaboration

35. T2K start-up Schedule • Neutrino beam will start in Apr. 2009 • ND280 on-axis detector will be ready for data taking when n beam starts • ND280 off-axis detector will be installed by fall 2009 to be ready for data taking • A plan to upgrade the Main Ring to 1.6 MW has been presented in the KEK roadmap • These experiments are the « Phase II » 35 A. Hatzikoutelis , T2K Collaboration

36. T2K ND280 purpose 36 A. Hatzikoutelis , T2K Collaboration