1. 2009/07/22NuFact09 at Chicago1 R&D towards Huge Liquid Argon Detectors for Nucleon Decay, Neutrino Astrophysics and CP-violation in the Lepton Sector T.Maruyama (KEK)

2. 2009/07/22NuFact09 at Chicago2 Physics motivation Giant LAr TPC is a good candidate to do neutrino physics and proton decay – to increase signal eff. / to reduce background using excellent tracking performance. – to have good energy resolution. Possibility to use for Neutrino Factory – with magnetic field. High temperature super- conducting magnet could be a good candidate to use. (e.g. high temperature super- conducting, see LAr TPC talk at NuFact05 by A.Rubbia )

3. 2009/07/22NuFact09 at Chicago3 Okinoshima 658km 0.8deg. Off-axis Cover Oscillation 1 st and 2 nd Maximum Neutrino Run Only 5 Years×1.66 MW 100kt Liq. Ar TPC -Good Energy Resolution -Good e/π ０ discrimination Keeping Reasonable Statistics Example of Physics Scenario δ=0° ν e Spectrum Beam ν e Background CP Measurement Potential NP08, arXiv:0804.2111 δ=90° δ=180°δ=270° sin 2 2θ 13 =0.03, Normal Hierarchy 

4. 2009/07/22NuFact09 at Chicago4 Example2; LAGUNA (+EUROnu) project

5. 2009/07/22NuFact09 at Chicago5 Concept of the LAr TPC Ionization selectron signal  ~5x10 4 e/cm MIP  3D track reconstruction as a TPC  drift velocity is ~mm/μs with ~kV/cm electric field  LAr purity affects the attenuation of the drift electrons.  No amplification inside LAr  Diffusion of the drift electrons is about 3mm after 20m drift Ionization electrons Scintillation light Cherenkov light Charged particle Electric Field  charged current event e charged current event A. Bueno, et.al.,, hep-ph/0701101 Liquid Ar 1 kV/cm Gas Argon 5kV/cm GEM readout Double phase Closed dewar

6. 2009/07/22NuFact09 at Chicago6 Introduction for LAr TPC R&D There are several LAr R&D efforts around the world. – US has remarkable progresses, especially, ArgoNEUT, MicroBoone and material test-stand. The former two will be covered by Maddalena Antonello later (WG2). – We think the charge readout (e.g. single and double phase readout) is an important R&D item to proceed. We’d like to show the new result on the readout from ETHZ-KEK collaboration.

7. 2009/07/22NuFact09 at Chicago77 Proposed Strategy @ Fermilab R. Rameika, Project X Workshop, January 2008 0.5x0.5x1.0 m 3 0.3 ton See talk by Maddalena Antonello 170 ton Data: ~2011-2012 Data: ~2015-2016 1-5 kton 100>M>5 1<N<20

8. 2009/07/22NuFact09 at Chicago8 100cm 50cm Pixel size = (4.0 x 4.0 x 0.3) mm 3 Neutrino candidate p m Large energy deposition Neutrino candidate in ArgoNeuT (ref. J.Spitz talk at FNAL user’s meeting on 4-Jun-2009)

9. 2009/07/22NuFact09 at Chicago9 Quest for the Origin of Matter Dominated Universe One of the Main Subject of the KEK Roadmap Discovery of Lepton CP Violation Proton Decay Discovery of the e Appearance Neutrino Intensity Improvement Huge Detector R&D Ｔ２Ｋ ( ２００９ ~) Water Cherenkov v Liquid Ar ＴＰＣ Establish Huge Detector Technology Construction of Huge Detector

10. 2009/07/22NuFact09 at Chicago10 Pros and Cons of Water Cherenkov and Liquid Argon Huge detector Water CherenkovLiquid Argon Pros matured technique 50 kton detector has been working for more than 10 years Easier to build huge and massive detector Possible to have excellent tracking performance, and it has directly impact to e appearance or proton decays search. Cons Cherenkov threshold is high for Kaons, protons, massive particles. electrons / pi0 separation is relatively bad compared to LAr TPC There are lots of R&D items to attack to achieve 100 kton level detector. -> therefore, I have this talk

11. 2009/07/22NuFact09 at Chicago11 Towards Huge LAr TPCs There are several proposals towards Huge LAr TPCs with different approaches: a modulable or a scalable detector for a total LAr mass of 50-100 kton evacuable or non-evacuable dewar -> evacuation guarantees the good purity. detect ionization charge in LAr without amplification or with amplification -> affects signal to noise ratio, etc. see later comments. Goal; Keep good physics performance with reasonable total cast for building.

12. 2009/07/22NuFact09 at Chicago12 Items to be Proven toward Huge Detector Technical Feasibility for Huge Detector (these are important for technology choice) –Establish realistic maximum drift distance Tightness of LNG (Liquid Natural Gas) type tank. Purification from non-evacuated large volume. Possible drift high voltage, and effect of the bubble inside the tank Ionization signal distortion for long drift, dE/dx –Use of passive insulation (thermal uniformity, stability, …) –Scaling up of purification capacity –Pre-cooling, flushing Physics Performance –Define tolerable charge signal distortion, dE/dx resolution –MC study needed (reconstruction,…) –Proof with Beam is necessary Calorimetry (energy reconstruction, electric field dependence, energy scale, etc should be investigated with electron/muon beam) Charged pions (hadron interaction in medium, electric field dependence)

13. 2009/07/22NuFact09 at Chicago13 Items to be Proven toward Huge Detector (2) Signal-to-noise ratio is one of main issues in liquid argon TPC – minimum ionizing track is releasing about 3 fC or about 17'000 electrons per 3 mm readout pitch, and dQ/dt decreases with drift length because of diffusion also attenuation due to impurities reduces further number of electrons problems for large detectors; – need very good charge preamplifier (expensive) and noise must be kept low in charge preamplifier depends on capacitive load at input typically 100-200 pF – it increases when wires are longer ---> longer wires ---> more noise – also environmental noise (computers, DAQ, clocks etc...) is bad – drift length is limited by attenuation and diffusion therefore our approach is to do new R&D on charge readout method on small scale setup prototype before trying to simply extrapolate existing technol ogy to large detectors

14. 2009/07/22NuFact09 at Chicago14 Results from small prototypes

15. 2009/07/22NuFact09 at Chicago15 CERN - 25 June 2009 Small setup to test double phase detector (ETHZ) Signal plane 30 kV feedthrough Signal cable HV connector TPB coated Level meters LEM (Large Electron Multiplier) is a thick macroscopic GEM arXiv:0811.3384 Readout; Anode; 6mm pitch Cu plane. LEM; 6mm pitch separated.

16. 2009/07/22NuFact09 at Chicago16CERN - 25 June 2009 Typical cosmic muon track Typical cosmic ray muon event: charge signals and related light signal. Scintillation light: primary light due to muon crossing LAr Proportional light: produced by electron in high extraction field in the gas

17. 2009/07/22NuFact09 at Chicago17 dQ/dx distribution Distribution of the energy loss per unit path length (  dQ/dx). Charge on the anode is corrected for the drifting e - lifetime. Gauss-convolved Landau function is fitted: MP ≈ 83 fC/cm  ≈ 14 fC/cm resolution ≈ 17% S/N = 80 / 1 They succeeded to have one week operation as a long run stability test. 26kV/cm For LEM (Gain10 Operation)

18. 2009/07/22NuFact09 at Chicago18 Operation with LEMs in liquid LEM-TPC can be operated with the LEMs completely immersed in LAr without charge amplification. This shows that LEM can be used as a readout even inside Lar. Gain = 1 S/N ≈ 80/5 Anode electrodes LEM electrodes Anode electrodes LEM electrodes Proof of LEMs transparency

19. 2009/07/22NuFact09 at Chicago19 LAr GAr LAr Open Bath Scroll Pump Turbo Pump Oxysorb (O 2 filter) Hydrosorb (H 2 O filter) Test Chamber Liquid Argon TPC R&D (KEK) Anode Cathode Grid Field shaper Inside chamber 10L Liquid Argon teststand was set up at KEK. - Gas Argon is liquefied after purification. - Test chamber is evacuated and baked before lique- faction. 4 channel strip was used for read out. (anode plane) Field shapers and grid plane are pre- pared. Sensitive area is ~ 9x9x5cm 3

20. 2009/07/22NuFact09 at Chicago20 First cosmic ray track at KEK (single phase) Trigger counters was set to measure cosmic ray track. We see the cosmic ray signal using the TPC (oscilloscope signal is shown below). – Signal timing is as expected. – First cosmic ray track at KEK 1234 Anode Cathode Trigger 2 (2cmx20cmx5mm) Trigger 1 (2cmx20cm X5mm(t)) Grid Open Bath trigger2 trigger1

21. 2009/07/22NuFact09 at Chicago21 2 Phase TPC with GEM (KEK) REPIC thick GEM – 400  m thickness – 300  m  hole – 700  m pitch GEM – Anode distance = 3 mm Nominal voltage – Cathode -9kV, Ext Grid -2.5kV – GEM  V=-1.8 kV and lower V = -300V Sensitive area: 9x9x4.5 cm Cathode: 9x9 cm copper plate Anode ： 9x2.2 cm copper plates – 4 ch readout Extraction Grid – 100  m SUS wire – 5 mm pitch (1D)

22. 2009/07/22NuFact09 at Chicago22 Cosmic Track (double phase) 22/28

23. 2009/07/22NuFact09 at Chicago23 250L test and 3 ton purging test 250L (right) and 3 ton (left) –250L; Test-beam (e/  at Japan) –Purification test without evacuation. At first, we purge the air using GAr Then purify the gas Can we obtain ppm level gas without evacuation?

24. 2009/07/22NuFact09 at Chicago24 Summary LAr TPC is a very important candidate for next generation neutrino physics and proton decay. There are many R&D items to achieve; – Tank/Vessel (incl. Purity without evacuation) – Possible high voltage for drift – Ionization signal distortion. –Scaling up of purification capacity –Good electronics and number of channels – Physics performance One solution to achieve the good signal-to-noise ratio even with attenuation is to use 2-phase TPC. Some results are shown here.

25. 2009/07/22NuFact09 at Chicago25 backups

26. 2009/07/22NuFact09 at Chicago26CERN - 25 June 2009 Readout electronics (ETHZ/CAEN) Custom made front-end charge preamp + shaper 2 channel per chip rise time 0.6  s, fall time 2  s Inspired by C. Boiano et al. IEEE Trans. Nucl. Sci. 52 (2004) 1931 In collaboration with CAEN, ADC and DAQ system development 12 bit 2.5 MS/s flash ADC. Programmable FPGA. Channel-by-channel trigger and global “trigger alert”. 256 channel crate. Chainable optical link.

27. 2009/07/22NuFact09 at Chicago27 ETHZ setup overview External bath Detector Purification circuit HV supply Vacuum pumps Readout electronics Input purification cartridge

28. 2009/07/22NuFact09 at Chicago28 Argon purification (ETHZ) Two purification stages Input LAr purification: Custom made cartridge for LAr purification at detector input. GAr purification circuit: Heating resistors evaporate LAr in the detector. A metal bellow pump pushes GAr into a flow meter and SAES getter (~48h to recirculate 1 volume). Purified GAr condensates into the detector volume. Filling procedure: The detector vessel is evacuated to 10 -6 mbar. The detector is filled with pure GAr (99.9999%) @ 1 bar. The external bath is filled, the detector cooled down while recirculating GAr through SAES getter. The detector is filled with LAr through custom made cartridge.

29. 2009/07/22NuFact09 at Chicago29 Double stage LEM with anode Produced by standard PCB methods. Double-sided copper-clad FR4 plates. Precision holes by drilling. Thickness: 1.6 mm. Amplification hole diameter: 500  m. Distance between centers of neighbouring holes: 800  m. Segmented anode and LEM2 top plane: 2x16 strips 6 mm wide. Anode LEM1 LEM2 10x10 cm 2 6 mm strips

30. 2009/07/22NuFact09 at Chicago30 The gain is measured from 109 Cd peak. The electric field is calculated as the ratio of  V across the LEM and the LEM thickness. Operation in pure gas argon (ETHZ) 55 Fe and 109 Cd sources positioned below the cathode grid Deposited energy is proportional to the sum of the involved strips Both anode and LEM signals can be used for the energy evaluation 55 Fe (full peak) ~5.9 keV 6.9 kBq 29.3% FWHM 55 Fe (escape peak) ~2.9 keV 6.9 kBq 42% FWHM 109 Cd ~22.3 keV 0.5 kBq 24.7% FWHM Pure argon gas operation, room temperature, 1.2 bar

31. 2009/07/22NuFact09 at Chicago31 Readout Electronics (KEK) Preamp – Charge amp – AMPTEK A250 – Gain: 1 V/pC – Rise time few ns – Decay time 300  s Postamp – NIM shaper amp – Hoshin N012 – Gain 1.0 – Time constant 0.5  s Oscilloscope – Tektronix TDS3014 Short pulse 4s4s 40  s Long pulse 40  s

32. 2009/07/22NuFact09 at Chicago32 Vacuum (KEK) Dry scroll pump – Variant SH110 Molecular turbo pump – Pfeiffer HiPace80 – Directly mounted on chamber Vacuum level – Baking @90 o C for few days 2x10 -4 Pa – Main source of outgassing HV feedthrough – 2x2x40cm Araldite bar w/o feedthrough 3x10 -5 Pa 32/28

33. 2009/07/22NuFact09 at Chicago33 Purification, Recirculation (KEK) Oxysorb, Hydrosorb – Air Liquide “Small Cartridge” – Specification < 1 ppm input Gas purity < 5 ppb Oxygen < 20 ppb Water Recirculation system – Gas -> Gas recirculation No heater inside chamber No heat exchanger – Initial filling and recirculation share the same filter – EMP (Enomoto Micro Pump) Diaphragm pump MX808-ST 25L/min 33/28

34. 2009/07/22NuFact09 at Chicago34 Purity Monitor Xenon flash lamp – Hamamatsu – Quartz window Optical fiber, feedthrough – Ocean Optics – good UV transmission Photo cathode – Cathode copper plate Readout – Anode signal only – Signal yield is stable within few% over few hours

35. 2009/07/22NuFact09 at Chicago35 Established the purity monitor signal with gas Argon (~1.2 atm) GEM sparks at HV > 1000V Signal pulse height w/o GEM was ~100mV – Gain = 1 at ~ 700V 35/28 GEM test using Ar Gas (KEK) 600V 800V

36. 2009/07/22NuFact09 at Chicago36CERN - 25 June 2009 Operation in double phase Radioactive sources were not suitable for cryogenic operation. Gain ~10 Raw images S/N ≈ 800/10 Charge multiplication occurs in argon vapour: 87 K, 1 bar, ~3.4 denser than at STP. LEM electrodes Anode electrodes LEM electrodes Anode electrodes E (kV/cm) Anode LEM 2 2.1 LEM 2 ~26 LEM 2 LEM 1 1.5 LEM 1 ~26 Drift0.7

37. 2009/07/22NuFact09 at Chicago37 Tracking Analyze oscillo- scope waveform Drift time - > z pos. Ch2 Ch4 Ch1 Ch3 Cathode plane Anode plane Multi-track event Single track event

38. 2009/07/22NuFact09 at Chicago38 Double Phase Detector Without Multiplication Sensitive area: 9x9x4.5 cm Cathode: 9x9 cm copper plate Anode ： 9x2.2 cm copper plates – 4 ch readout Field Shaper (SUS) – 9x9 cm x0.8 mm – 8 mm distance (5 th is grid) Extraction Grid – 100  m SUS wire – 5 mm pitch (1D) Shielding Grid – 100  m SUS wire – 5 mm pitch (2D mesh) Anode Cathode Shielding Grid Field shapers Extraction Grid (Gas) Extraction Grid (Liquid)

39. 2009/07/22NuFact09 at Chicago39 3ton purging test

40. 2009/07/22NuFact09 at Chicago40 Towards large LAr TPCs Starting from ICARUS (1985), several proposals towards large LAr TPCs:  LANNDD 2001  GLACIER 2003  FLARE 2004  MODULAR 2007 …with different approaches: a modular or a scalable detector for a total LAr mass of 50-100 kton evacuable or non-evacuable dewar detect ionization charge in LAr without amplification or with amplification

41. 2009/07/22NuFact09 at Chicago41 A LINE OF LIQUID ARGON TPC DETECTORS SCALABLE IN MASS FROM 200 TONS TO 100 KTONS David B. Cline 1, Fabrizio Raffaelli 2 and Franco Sergiampietri 1,2 1 UCLA 2 Pisa, ETHZ, Bern U., Granada U., INP Krakow, INR Moscow, IPN Lyon, Sheffield U., Southampton U., US Katowice, UPS Warszawa, UW Warszawa, UW Wroclaw MODULAR GLACIER ICARUS FLARE LANNDD Bartoszek Eng. - Duke - Indiana - Fermilab - LSU - MSU -Osaka - Pisa - Pittsburgh - Princeton – Silesia – South Carolina - Texas A&M - Tufts - UCLA - Warsaw University - INS Warsaw - Washington - York-Toronto

42. 2009/07/22NuFact09 at Chicago42 A scalable detector with an evacuable dewar and ionization charge detection without amplification LANNDD  Drift paths up to 5 m  Evacuable dewar with the possibility of checking its tightness  Use of stainless steel for the inner vessel and for cathodes, wire chamber frames and shaping electrodes  UHV standards for any device in contact with the argon  Vacuum insulation, together with the use of superinsulation jacket around the cold vessel, to reduce running costs  A continuous (not segmented) active LAr volume (high fiducial volume) contained in a cryostat based in a multi-cell mechanical structure  This solution allows a cubic shape composed by n 3 cells, 5m×5m×5m in size each n=3, ~5 kton D.B. Cline, F. Raffaelli, F. Sergiampietri, JINST 1, T09001, 2006

43. 2009/07/22NuFact09 at Chicago43 MODULAR Perlite insulation Low conductivity foam glass light bricks for the bottom support layer Geometry of an ICARUS-T600 half-module (T300) “cloned” into a larger detector scaled by a factor 8/3 = 2.66: the cross sectional area of the planes is 8 x 8 m 2 rather than 3 x 3 m 2. The length of such a detector is 50 meters. A modular detector with a non-evacuable dewar and ionization charge detection without amplification B. Baibussinov et al., arXiv:0704.1422 [hep-ph]  2 modules of 5 kton each with common insulation  1.5 m thickness of perlite, corresponding to ~ 4 W/m 2 thermal loss  wires at 0°, ±60°  0° wires split in two, 25 m long, sections  6 mm wire pitch, to compensate for the increase capacitance of the longer wires

44. 2009/07/22NuFact09 at Chicago44 FLARE A scalable detector with a non-evacuable dewar and ionization charge detection without amplification 50 kton LAr Fermilab-Proposal-0942, Aug. 2004 hep-ex/0408121 LNG style tank: CB&I standard design for double wall and double roof vessel 30 m 40 m  Thermal insulation 1.2 m thick layer of perlite boil-off rate of 0.05%/day (25 ton/day) a cryogenic system is necessary in order to re-liquefy this gas mass  Wire planes 3 m drift distance, 5 mm wire spacing large wire planes, with the largest of 30x40 m 2

45. 2009/07/22NuFact09 at Chicago45 A 5 ton detector is a cylinder 5 meters high with diameter 1 meter. A 5 kton detector is a cylinder 17 meters high with diameter 17 meters 1 meter wire panel Field grid 17 meters Field grid LArTPC @ Fermilab A scalable detector with a non-evacuable dewar and ionization charge detection without amplification cellular design for wire planes LNG style tank

46. 2009/07/22 NuFact09 at Chicago 46 A.Bueno et al NP08 (@Mito) on Mar-6-2008 46 e   oscillation probability e   oscillation probability Atmospheric Interference Solor Interference term plays important role!!

47. 2009/07/22 NuFact09 at Chicago 47 A.Bueno et al NP08 (@Mito) on Mar-6-2008 47 Parameters for oscillation  m 31 2 = 2.5x10 -3 eV 2  m 31 2 = 2.5x10 -3 eV 2  m 21 2 = 8.2x10 -5 eV 2   23 = /4   12 = 0.573  = 2.8 g/cm 3 for matter effects (all parameters are same as PRD 76, 093002 (2007)) (all parameters are same as PRD 76, 093002 (2007))  These parameters are assumed to be well determined, thus free parameters are only  13 and  CP.