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A New Experiment To Measure θ 13

A New Experiment To Measure θ 13

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A New Experiment To Measure θ 13

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  1. A New Experiment To Measure θ13 David Reyna Argonne National Laboratory

  2. CKM Matrix MNS Matrix 3 Flavor Mixing Matrix David Reyna - ANL

  3. Mixing Angles Matrix Components: 3 Euler Angles (θ12; θ13; θ23) 1 CP phase (δ) (+2 Majorana Phases) Atmospheric (νμνx) Solar (νeνx) The Next Big Thing? David Reyna - ANL

  4. Current Experiments Unconfirmed observation by LSND, currently being investigated by MiniBooNE. Would require the existence of sterile neutrinos or CPT violation. Measured by Super-K and confirmed by Soudan2 and K2K. First observed by Ray Davis and collaborators. Measured by Super-K, SNO and KamLAND. David Reyna - ANL

  5. Δm2(aka: LSND problem) • For 3 νonly 2 independent mass differences • Mass hierarchy unknown Normal Inverted m3 m2 m1 m2 (m2atm~ 2 x 10-3 eV2) m2 m1 m3 (m2solar~ 7 x 10-5 eV2) David Reyna - ANL

  6. Current q13 Bound Current Limits are set by experiments which were not trying to measure θ13 Optimization of the experiments for this goal was never done In currently allowed range (Δm2 =1.3-3 x 10-3 eV2) sin2(2θ13) < 0.19 @ 90% CL David Reyna - ANL

  7. How to Measure q13 • Appearance measurement • Accelerator measurements look for small νe appearance in νμ beam P(nmne) = sin2(2q13)sin2(q23)sin2(Dm2atm L/4E) • Disappearance measurement • Reactor measurements look for small νe disappearance from large isotropic flux P(nene) = 1 - sin2(2q13)sin2(Dm2atm L/4E) David Reyna - ANL

  8. Accelerator Difficulties • Signature is electron appearance • Requires massive detector with fine granularity (be able to distinguish e from P) • Backgrounds • ne in the beam, (~1%, from m, Ke3, K0e3) • Fake ne from nt, te, (at high energy) • Showers which look like e’s, particularly nNnNp0, p0gg • Measurement has degeneracies due to cp-violation and matter effects David Reyna - ANL

  9. ne Appearance in a nmbeam P(nmgne) = (2c13s13s23)2 sin2F31 +8c13s12s13s23(c12c23cosd-s12s13s23)cosF32sinF31sinF21 -8c13c12c23s12 s13s23sindsinF32sinF31sinF21 +4s12c13(c12c23+s12s23s13-2c12c23s12s23s13cosd)sin2F21 -8c13s13s23(1-2s13 )(aL/4E)cosF32sinF31 2 l CP violating 2 2 2 2 2 2 2 2 2 2 2 2 a = constant X neE CP: ag-a, dg-d David Reyna - ANL

  10. Understanding the Degeneracy d Minakata and Nunokawa, hep-ph/0108085 ~cosd • There are 2 Observables • P(nmne) • P(nm ne) • Interpretation in terms ofsin22q13, dand sign ofDm223 depends on the value of these parameters and on the conditions of the experiment: L and E ~sind sin22q13 David Reyna - ANL

  11. Experimental Solutions • If θ13 is large, the degeneracy can be broken with Off-Axis measurements • Measure both ν and anti-νrates • Multiple experiments with different baselines and different energies • Will yield a rich physics program for cp-phase and mass hierarchy • If θ13 is zero, degeneracies collapse but there’s no attainable physics gain • Big cost - big risk David Reyna - ANL

  12. The Reactor Measurement P(nene) = 1 - sin2 2q13 sin2(Dm2atm L/4E) - cos4q13 sin2 2q12 sin2(Dm2sol L/4E) solar No CP-violation in a disappearance measurement Distance (~1Km) is too short for matter effects P atmospheric L/E(km/MeV) David Reyna - ANL

  13. All measure the same energy spectrum. Previous experiments used single detector and were limited by 3% uncertainty in reactor power. KamLAND is first to see positive evidence of oscillation. Future experiments propose 2+ detectors of 10-100 tons (not kilotons). Previous Reactor Measurements KamLAND sees a 40% deficit/shape at 200km related to Dm212 Search for a 1-5% deficit/shape at ~1 km related to Dm213 David Reyna - ANL

  14. Prompt _ g n e+ 511 keV e+ e- p p g n 511 keV ~200 ms g n 2.2 MeV p Delayed How to Detect a ne Event David Reyna - ANL

  15. Reactors provide a fairly steady flux of 1-10 MeV n’s Neutrino energy carried by positron Eν= Ee+ + 0.8 MeV Adding Gd moves n-capture peak from 2.2 MeV to 8 MeV and reduces capture time to ~10μs • νe interactions in detector‡ [day MeV]-1 • νe flux at detector‡ [108/(s MeV cm2)] • σ(Eν) [10-43 cm-2] Reactor n’s ‡ from Palo Verde David Reyna - ANL

  16. The Double Chooz Concept • Measure neutrino flux before and after oscillation • Measure difference from 1/r2 dependence • Improve detector design to reduce systematics e e,, D2 = 1,050 m D1 = 100-200 m 8.4 GWth Chooz PWR power station Near detector Far detector David Reyna - ANL

  17. Who is Double Chooz? Saclay, APC, Subatech, TUMunich, MPIK-Heidelberg, Tubingen Univ., Univ. Hamburg, Kurchatov, LNGS, Lousiana State, Argonne, Drexel Univ. Alabama, Univ. Notre Dame, Kansas State, Univ. Tennessee David Reyna - ANL

  18. Chooz-far Chooz-near EdF Has Approved Access to All Sites David Reyna - ANL

  19. 250 m 125 m Distance Reactor-detector Required overburden (m.w.e) 100 45-53 150 55-65 200 67,5-80 Far Near Sites • 60 m.w.e. overburden • 12 m compacted earth • 3 meter high density material DAPNIA David Reyna - ANL

  20. Reactor Challenges • Long term stability (Liquid Scintillator) • Chooz/Palo Verde were few month exp’s • Next generation must be 3-5 years • Backgrounds • Chooz measured ~10% with reactor off • Unlikely to duplicate reactor off data • Systematic Error Control • Consistency of mechanical construction • Previous exp’s were 2-3% (excluding reactor) • Needs to be 1% or less David Reyna - ANL

  21. Gd doping has resulted in poor stablity of liquid Scintillator Palo Verde had problems with precipitation/condensation Mystical fix with water vapor Chooz saw a very rapid decay of attenuation length Heidelberg and LNGS (LENS/Borexino) have been working for the last 3-5 years to understand these effects Simple dissolved Gd solutions are very sensitive to pH Attempting to bind Gd into the chemical structure of the liquid Long Term Stability (Liquid Scintillator) Eur.Phys.J. C27 (2003) 331-374 David Reyna - ANL

  22. R-COO- 3+Gd R-COO- (R-COOH)x -OOC-R Gd doped scintillator • Solvant: 20% PXE – 80% Dodecane • Gd loading: 3 recipes developed @Heidelberg & LNGS • Gd-CBX • Good stability @20oC • Suitable baseline – End of development • Gd-Acac • Good stability @20oC • Low solubility in PXE  warning • Difficult to purify • Gd-Dmp • Good stability @20oC • High solubility in PXE+dodecane • OK for purification • Synthesis to optimize 3+Gd LY~8000 /MeV L = 5-10 m 6 g/l PPO 20 mg/l BisMSB Gd-Acac Gd-Dmp Gd-Carboxylate David Reyna - ANL

  23. 20C - long period test All Gd-CBX,Acac, Dmp are stable Yb sample stable since 4,5 years (small sample) In sample stable since 1,5 years (2 liters, 1 year meas. @LNGS) High Concentration Test LENS R&D: Yb, Gd, In  2 In-sampled loaded at 5% measured for 1 year @ LNGS and found stable (10-20% error) 6 month 1% Gd-CBX Stable  work in progress High Temperature Test 40C for several weeks to accelerate aging Still under investigation Next Step: large scale production and stability test Gd Doped Scintillator Aging Tests Gd-Acac Heidelberg Gd-CBX (test in Saclay) Gd-CBX David Reyna - ANL

  24. Accidental Backgrounds Mainly at Low E Best measurement from Borexino(CTF) Must reduce few MeV radioactive sources and thermal neutrons Correlated Backgrounds Mainly from cosmic muons Best measurements from KamLAND but hard to extrapolate to shallow depth Must reduce overall muon rate and attempt to veto background candidates n + Gd   ~ 8 MeV E >~ 1 MeV n deposits energy n Gd  ~ 8 MeV Backgrounds accidental background (uncorrelated) correlated background +-n cascades David Reyna - ANL

  25. Cosmic muons create fast neutrons Spallation in the rock surrounding the detector Muon capture in the detector materials Fast neutron slows down by scattering into the scintillator (depositing energy) and is later captured on Gd ! Full simulation – Geant + Fluka Old Chooz configuration: 300 m.w.e. 31hours – to validate MC Simulated: Nb<1.6 evts/day (90% C.L.) Measured in-situ: Nb=1.1 evts/day Double-Chooz configuration: 338 106 μ tracked – 580 103 neutrons tracked 1 neutron created a background event Far detector expectation: Nb<0.5 evt/day (90% C.L.) Near detector expectation: Nb<3.2 evts/day (90%C.L.) μ μ μ capture n from  capture Recoil p Gd Gd Recoil p n capture on Gd Spallation fast neutron Neutron Induced Background David Reyna - ANL

  26. β-neutron Cascades (Cosmogenics) crossing the detector Likely to be seen by the Veto 8He 9Li 11Li β decayed followed by n emission within 200 ms ! (not veto-able) μ interaction on 12C David Reyna - ANL

  27. Large singles rate PMT glass in scintillator Used vertex cut to reduce effect but with increased systematic error New detector design will eliminate this effect Took data with all reactors off Allowed direct measurement of correlated backgrounds Consistent with other analysis methods for eliminating backgrounds Known environment for future experiment Chooz Backgrounds Eur.Phys.J. C27 (2003) 331-374 David Reyna - ANL

  28. Background Estimates • Chooz (300 mwe) 5.5 m3, Noise/Signal ~ 4% • Correlated events (neutrons): • Chooz : ~1 recoil proton per day • Double-Chooz-Far (300 mwe) 12.7 m3, Signal x 2.4 • Uncorrelated (, + n capt. on Gd): Sx3 & N/3  can be subtracted • Correlated events (neutrons): • Goal <1 events per day + known spectrum  N/S<~1% • Correlated events (cosmogenics) • Double-Chooz-near (60 mwe) 12.7 m3, Signal x 30-50 SFAR • Key advantage: Dnear~150 m  Signal x ~30-50 • Uncorrelated: Chooz-Far backgrounds x 50  can be subtracted • Correlated events: Chooz-Far x <30  N/S < 1% • Correlated events (cosmogenics) • (but not a comprehensive list of backgrounds …) David Reyna - ANL

  29. Additional Outer Veto at Near Detector David Reyna - ANL

  30.  target:80% dodecane + 20% PXE + 0.1% Gd (acrylic, r = 1,2 m, h = 2,8 m, 12,7 m3) -catcher:80% dodecane + 20% PXE (acrylic, r+0,6m – V = 28,1 m3) 511 keV 511 keV Non-scintillating buffer: same liquid (+ quencher?) (r+0.95m, , V = 100 m3) e+ e p Gd n PMTs supporting structure  ~ 8 MeV Muon VETO: scintillating oil (r+0.6 m – V = 110 m3) Shielding: 0,15 m steel New detector design 7 m 7 m David Reyna - ANL

  31. Systematic Breakdown 25 @ 15m ‡ Signal/Background = 2.2 @ 40m 0.7 @ 95m David Reyna - ANL

  32. Detector Relative Comparison • Solid angle • Distance measured @10cm + Monitoring of the  source barycenter … • Target volume • @CHOOZ : 0.3% [simple measurement] • Goal ~0.2% [same apparatus for both detectors] – • Test - scale 1 - in progress • Density • 0.1% achievable, but accurate temperature control mandatory • H/C ratio & Gd concentration • Absolute measurement is difficult : 1% error @CHOOZ • Plan: use the same batch to fill both detectors • Boundary effect at the inner vessel interface (spill in/out) • Neutron transport slightly different due to solid angle effect • Live timeto be measured accurately by several methods David Reyna - ANL

  33. @Chooz: 1.5% syst. err. 7 analysis cuts Efficiency ~70% Goal Double-Chooz: ~0.3% syst. err. 2 to 3 analysis cuts Selection cuts neutron energy distance (e+ - n ) [level of accidentals] t (e+ - n) e+ e p Gd n Relative Normalization: Analysis e+ n t David Reyna - ANL

  34. Double Chooz Goal Original Chooz Detector Error How Good is Good Enough? David Reyna - ANL

  35. Understanding Mechanical Construction AcrylicTarget vessel (R=1,2m, h=2,8m, t = 12mm) Acrylic Gamma catcher vessel (R = 1,8m, H = 4 m, t = 8mm) LS + 0,1%Gd LS Stainless steel Buffer (R= 2,75m, h = 5,6m, t = 4mm) Muon VETO (shield) Thickness = 150mm David Reyna - ANL

  36. Acrylic selected Material compatibility test ongoing (OK with Security Factor = 8) Prototype 1/5 by june 2005 (call for bid sent) Acrylic Integration A special Tool will be developed to rotate/insert the acrylic vessel into the pit after PMT mounting Test of accessibility in Chooz tunnel with acrylic vessel model CEA/DAPNIA David Reyna - ANL

  37. Mechanical Studies David Reyna - ANL

  38. Scale (1:5) Prototype PMT Cable Routing AcrylicTarget Vessel LS + 0,1%Gd LS Acrylic Gamma Catcher Vessel Stainless Steel Buffer Muon VETO Goal: technical solutions for construction and integration David Reyna - ANL

  39. Additional Work Ongoing • PMTs • Testing radioactivity • Mounting systems • Electronics/HV • Prototype designs are under study • DAQ system is under design • Calibration • Fiber Optic/LED system • Articulated arm vs. Rope-and-Pulley development • Wire driven Guide Tubes for Gamma Catcher • Radioactive source development • Simulation • Full G4 Detector Simulation (derivative of KamLand) • Complete optical properties • All Chemical Properties • Muon/fast neutron in G4 and FLUKA • Feeding back the R&D into the simulation effort • Non-Proliferation • Collaboration with LLNL and IAEA • Interest in monitoring reactor power and fuel composition David Reyna - ANL

  40. Status of Double Chooz (Europe - I) • EDF has agreed to the project • Allow use of the original laboratory • Agreed to location for near laboratory (150-200 meters from core) • French funding agency has approved the project • Provide ½ the funding for detector construction • Agreed to fund the construction of the near laboratory • Awaiting complete engineering analysis and costs from EdF • Contracts for prototype construction are already under negotiations for bids • MPI-Heidelberg is providing independent funding for Liquid Scintillator development and production David Reyna - ANL

  41. Status of Double Chooz(Europe - II) • Germany still has other institutions seeking ‘normal’ funding • 5 year cycle but they are in the queue • Italy is working on LS but has no funding • Rumors that the canceled BTeV may free up Italian money • Russians have agreed to produce radioactive sources but little money is expected David Reyna - ANL

  42. Status of Double Chooz(U.S.) • Submitted proposal to DOE in October ‘04 • $4.8M over 3 years for total project • Already secured forward funding of $3M • DOE has decided to not decide • Establishing neutrino SAG • Double Chooz Construction Proposal competes with R&D requests from Braidwood and Daya Bay • US groups are continuing to finalize design work on expectation of approval • New groups are continuing to join • Recent additions of Los Alamos and Livermore David Reyna - ANL

  43. Far detector starts Near detector starts 2004 2005 2006 2007 2008 2009 2003 Site Proposal & design Construction ? Data taking Expected Schedule • Detector Construction • Can begin in 2006 (No known reason for delays in construction and installation of far detector) • Near Laboratory • Finalize designs in 2005 • Hope to have civil construction 2006-7 • Install near detector at end of 2007 or early 2008 • Data Taking • Can begin taking data with far detector as soon as it is installed (middle 2007) • Near detector will hopefully follow in 16 months David Reyna - ANL

  44. Far Detector starts in 2007 Near detector follows 16 months later Double Chooz can surpass the original Chooz bound in 6 months sys=2.5% sys=0.6% Far detector only Far & Near detectors together 05/2007 05/2008 05/2009 05/2010 Expected Sensitivity 2007-2012 90% C.L. contour if sin2(213)=0 m2atm = 2.8 10-3 eV2 is supposed to be known at 20% by MINOS David Reyna - ANL

  45. A positive signal within the Double Chooz range would signify a very rich program at the accelerator measurements A null result would imply a difficult path Double Chooz is the only experiment which can provide such a direct result in a short time period (~3-4 years) Double Chooz Complements Off-Axis from M. Shaevitz Sensitivity regions for resolving the Mass Hierarchy at 2 (with Proton Driver) David Reyna - ANL

  46. Conclusion & outlook • Strong Collaboration • Saclay, APC, Subatech, TU Munich, MPIK-Heidelberg, Tubingen Univ., Univ. Hamburg, Kurchatov, Lousiana State, Drexel, Argonne, Univ. Alabama, Univ. Notre Dame, Kansas State, Univ. Tennessee, LNGS • Experience from Chooz, Palo Verde, KamLAND, Borexino, LENS • Known Technology • Conservative design (incremental improvement on Chooz) • Reasonably achievable improvements in detector systematics • Known Environment • Direct comparison to previous Chooz results / backgrounds • Excellent Physics Opportunity • Current Chooz bound is sin2(213)<0.19 @ 90% C.L • Expect sensitivity of sin2(213)<0.02-0.03 with 3 to 5 year run • Continuing to maintain aggressive schedule • Price is right! David Reyna - ANL