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									     The n Odyssey 2002:
      SNO & KamLAND




                  Alan Poon
  (for the SNO and KamLAND Collaborations)
    Institute for Nuclear and Particle Astrophysics
Lawrence Berkeley National Laboratory, Berkeley, USA
   Outline

        • Introduction — the Solar Neutrino Problem
        • Demonstration of Solar Neutrino Flavour
          Transformation (nenm,):
                     Sudbury Neutrino Observatory
        • Testing Solar Neutrino Oscillation Hypothesis
          Using Reactor Anti-Neutrinos:
                  Kamioka Liquid Scintillator Anti-
                  Neutrino Detector
        • Outlook

Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
 Solar Model Prediction of Solar ne Flux

   pp chain:
   4p + 2e  4He + 2ne + 26.7 MeV                                                 SuperK, SNO(CC)
                                                                           SNO( NC)
                                                      Gallium   Chlorine




    Detailed computer
     model of solar
        evolution




            Standard
              Solar
             Model
Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   Solar Neutrino Problem (circa 2000)
                                                                  fGa (n e )
                                                      GALLEX:                 0.58  0.05
      Experiment                      Reaction
                                                                 fSSM (n e )
 Homestake                         ne+37Cl37Ar+e                 fGa (n e )
                                  ne+71Ga71Ge+e      SAGE :                  0.60  0.05
 SAGE                                                            fSSM (n e )
 Gallex + GNO                     ne+71Ga71Ge+e
 Kamiokande +                                                     fCl (n e )
                                                      Homestake:              0.34  0.03
 Super-Kamiokande                     nx+enx+e                  fSSM (n e )
                                                                  fSK (n x )
                                                      Super- K :              0.4510.017
                                                                                     0.015
                                                                 fSSM (n e )

                                       either
                                   
                       Solar models are incomplete/incorrect
                                         or
                        Neutrinos undergo flavor-changing
                                  transformation

Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   A Proposal to Hunt for the Missing n’s




                                                      Phys. Rev. Lett. 55, 1534 (1985)




Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   Sudbury Neutrino Observatory




                                                      2 km to surface
       17.8m dia. PMT Support Structure                                     1006 tonnes
       9456 20-cm dia. PMTs                                                     D2O
       56% coverage

              12.01m dia. acrylic vessel

    1700 tonnes of inner shielding H2O                                                            Urylon
                                                                                                  liner
     5300 tonnes of outer shielding H2O


Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
                                                                        Nucl. Inst. Meth. A449, 127 (2000)
   Detecting n at SNO
   CC      n e  d  p  p  e-
  • Measurement of ne energy spectrum
  • Weak directionality: 1 0.340cos 


   NC       n x  d  p  n n x
  • Measure total 8B n flux from the sun
  • (ne)(nm)(n)


   ES        nx  e-  nx  e -
 • Low Statistics
 • (ne)  6 (nm)  6 (n)
 • Strong directionality: e  18                     ( e  10 MeV)
                                                      T

Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   Let’s Go Catch Some Z’s
  The physics program at SNO is tailored to measure the total solar n flux via
  the Neutral-Current reaction with different systematics:

  Phase I                                   Phase II                   Phase III
  (pure D2O):                               (dissolved NaCl):          (3He n counters):
   Neutron capture on D                      Neutron capture on Cl      n  3He  p  t

    Single 6.25 MeV g                         gcascade, 8.6 MeV


    Statistical separation                    Statistical separation   Independent
    (Energy, radius)                          (Light Isotropy)         channel


   High CC-NC correlation Better CC-NC separation NC uncorrelated to CC

    Past                                       Present                 Future
    (Nov 99 to May 01)                         (since June 01)         (Sep 03 ?)
Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
 Analysis Example: Energy Response (SNO Phase I)
 Calibration:
 • PMT & Optics
 • Normalized to 16N [Eg=6.13 MeV]                    E/E = ± 1.21%
 • Check with                                         / = + 4.5%
     • 8Li [13 MeV b]                                 Linearity = ±0.23% @ Ee=19.1 MeV
     • 252Cf [d(n,g), Eg=6.25 MeV]
     • 3H(p,g) [19.8 MeV g]
                                                                          fCC/fCC   fNC/fNC
                                                                           4.3       6.1
                                                             E            4.2
                                                                                %          %
                                                                                      6.2
                                                                           0.0       4.4
                                                                              %          %
                                                                           0.9       0.0
                                                                            
                                                             Linearity     0.1%      0.4%
                                                                         4.3
                                                                              
                                                                                     7.5
                                                             Total              %         %
                                                                           4.3      6.2
                                                                            


                                                                          
Alan Poon, I.O.P HEPP Particle Physics 2003, Durham   Energy
 Extracting the Solar n Flux (SNO Phase I)
      CC                     NC                       ES
                                                                                        Radioactive
                                                                        n Signals
                                                                                        Backgrounds

                                                                     Amplitudes Free Amplitudes Fixed

                                                                         Perturb
                                                                       Observables:    Shift amplitudes
                                                                                             (±1 )
                                                                          R, u , T

                                                                     Max.
                                                                     Likelihood Fit
                                                                


                                                                        f CC f NC f ES
                                                                                OR        +     f
  • PDFs:                                                                    f e fm
  kinetic energy T, event location R3,
  and solar angle correlation cos sun                     
Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
Signal Extraction Results (SNO Phase I)
  • 306 live days (Nov 1999 to May 2001)
   Assume standard 8B n spectrum
   Null hypothesis:
   no neutrino flavour transformation
                            +61.9
   CC          1967.7       -60.9    events
                            +49.5
   NC            576.5      -48.9    events
                            +26.4
   ES            263.6      -25.6    events




Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
 Flux Uncertainties (Shape constrained)

                                     0          5     10   15   20   25
                  Energy Scale
           Energy Resolution
             Vertex Accuracy
            Vertex Resolution                                              fCC
                                                                          fcc
          Angular Resolution
      Neutron backgrounds
           Cer. Backgrounds                                               fNC
                                                                          cnc
             Neutron Capture
                       Statistics
                             Total




Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   Missing Solar n’s Found
                                   fCC (n e )  f e
                                   f NC (n x )  f e  f m                 0.05         0.09
                                                                  fe  1.76 0.05 (stat.) 0.09 (syst.) 10 6 cm2s 1
                                   f ES (n x )  f e  0.15f m

                                                                   ENull> 2.2 MeV
                                                                             0.45         0.48
                                                                  f m  3.410.45 (stat.) 0.45 (syst.)10 6 cm2s 1


                       
                                                                    n hypothesis of no
                                                                       (But fe = fCC was measured
                                                                     flavour transformation
                                                                              for Te > 5 MeV)
                                                                       rejected at 5.3
                                                                       See : Phys.Rev.Lett. 89 (2002) 011301
                                                                             Phys.Rev.Lett. 89 (2002) 011302


                                                                             1.01
 Solar Model predictions are verified:                    fSSM (BP01)  5.05 0.81
 [in 106 cm-2 s-1]
                                                                                         0.44             0.46
                8B   nshape constrained fit:             fSNO
                                                           constrained
                                                                               5.09
                                                                                         0.43
                                                                                                 (stat.)
                                                                                                           0.43
                                                                                                                   (syst.)

                                                                                1.57         0.55
                 No   8B   nshape constraint:            fSNO
                                                           unconstrained
                                                                          6.42       (stat.)       (syst.)
                                                                              1.57         0.58
Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   Corrections Made Accordingly




Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   Corrections Made Accordingly
                                                                        SuperK, SNO(CC)
                                                                 SNO( NC)
                                        Gallium       Chlorine




Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
Correlation in Signal Extraction (Phase I)
        Strong statistical anti-correlation between NC and CC in the
        signal extraction

                                                           Correlation Matrix
                                                               CC      ES       NC
                                                      CC      1.000   -0.162   -0.520
                                                      ES     -0.162   1.000    -0.105
                                                      NC     -0.520   -0.105   1.000




Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   Light Isotropy in Phase II
  • CC and ES signals yield an electron, which produces a single cone of
    Cherenkov light
  • In Phase I (pure D2O), NC signal yields a single g, whereas in Phase II
    (salty D2O) there are multiple g’s following n capture on 35Cl
  • We can use light isotropy to help distinguish CC and NC




Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
  Light Isotropy in Phase II

                  Variables CC                   NC          ES
                              Stat.              Stat.       Stat.
                              Error              Error       Error

              {
Published         E,R,sun    3.4 %              8.6%        10%
D2O *             R, sun     9.5%               24%         11%




                                                                         Preliminary
                  E,R,sun    4.2%               6.3%        10%
Simulated
  D2O +
  NaCl       {    E,R,sun, 3.3%
                  Iso.
                  R,sun,Iso. 3.8%
                                                 4.6%

                                                 5.3%
                                                             10%

                                                             10%
        Simulations assume 1 yr of data, with .35 SSM for CC, .5 SSM for ES,
        and 1 SSM for NC.
Alan Poon, I.O.P HEPP Particle Physics 2003, Durham * PRL, 89, No. 1, 011301, (2002)
   Decoupling CC and NC in Phase III
 • CC: Cherenkov Signal  PMT Array
 • NC: n+3He  Neutral Current Detector Array
                                                                                    Phase III
                                                                       Phase I      Projected
                                             Source                   NC/NC (%)   NC/NC (%)
                                           Energy Scale ¶             -6.2, +6.1       ~0
                                           Energy Resolution ¶        -0.0, +4.4       ~0
                                           Energy Non-linearity ¶     ±0.4             ~0
                                           Vertex Resolution ¶        ±0.1             0.0
                                           Vertex Accuracy            ±1.8             0.0
                                           Angular Resolution         -0.3, +0.3       0.0
                                           Internal Source p-d ¶      -1.5, +1.6       3.0
                                           External Source p-d ¶      -1.0, +1.0       1.0
                                           D2O Cherenkov ¶            -2.6, +1.2       0.0
                                           H2O Cherenkov              -0.2, +0.4       0.0
                                           AV Cherenkov               -0.2, +0.2       0.0
                                           PMT Cherenkov ¶            -2.1, +1.6       0.0
                                           Neutron Capture            -4.0, +3.6       3.0
                                            Systematic               -8.5, +9.1      4.5
                                            Statistical              -8.5, +8.6       4
                                            Uncertainties               12            6
                                           ¶ CC NC anti-correlation
Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   SNO Summary
  Phase II (D2O+NaCl)
  • Final full-scale detector calibration before the removal of salt
    is in progress
  • Salt to be removed in about a month
  • Intense analysis activities in progress


   Phase III (Neutral Current Detector)
  • All 3He counters have been constructed and stored in the
  underground lab
  • Integration of electronics and DAQ in progress
  • Deployment in September 2003

Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   2-Flavor Neutrino Oscillation
     Mass states (nM)                 Weak states (nW)
     mass: m1, m2                     (participate in weak       e  cos 
                                                                 n                        
                                                                                   sin   n 1 
                                       interactions)                               
                                                                                          
                                                                 n       sin 
                                                                 m           cos   n 2 
                                                                                          
           n1         n2                     ne          nm
                           Pure ne                    Pure ne       Pure ne


                                                                            n1
                                                                              n2


                                            Time
                                           m 2 [eV 2 ] L[m] 
           P (n e  n m )  sin 2 sin 
                                       2
                                        1.27      2
                                                                where m  m2  m1
                                                                          2   2    2
                                             E [MeV]         
     Note:       May also have resonant flavor conversion in matter —
                 Mikheyev-Smirnov-Wolfenstein (MSW) effect
Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   Global Solar n Analysis
   Inputs:     • 37Cl, latest Gallex/GNO, new SAGE, SK 1258-day day & night spectra
               • SNO day spectrum (total: CC+NC+ES+background)
               • SNO night spectrum (total: CC+NC+ES+background)
               • 8B floats free in fit, hep n at 1 SSM




        SNO data only                                 Global




Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   If CPT is conserved…(and LMA…)
                                       Predicts deficit in
              Solar ne                                       Reactor ne
                                                                    ~100 to 200 km




      Complementary!
Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   Is n Oscillation Really the Solution?
  Kamioka Liquid scintillator
  Anti-Neutrino Detector
  (KamLAND)
  (Kamioka, Gifu Prefecture, Japan)
   reactor n@ ―right‖ baseline for
  directly testing the currently
  favoured LMA region
  1 kt liquid scintillator as target
                                        
   ne  p  n e
   2x coincidence
                                     e  e   2g

                  n  p d  g (2.2 MeV)
 (inverse b decay)
                  
Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
    The KamLAND Detector
• 1 kton liquid scintillator
          80% mineral oil
          20% pseudocumine                             "Dome" Area
          1.5 g/L PPO (fluor)
          =0.78 g/cm3
                                                        Steel Deck
•Mineral oil outside a 130-mm thick,
13-m diameter nylon balloon
                                                      Outer Detector
      =0.76 g/cm3                                    Water Cherenkov
• A 3-mm thick acrylic radon barrier                    Steel Sphere
at 16.6-m diameter to reduce Rn
                                                       Nylon Balloon
•   1879 PMT's
        1325 17‖ brand new                             Tyvek light
          544 20‖ from K-II                            baffle
        34% photocathode coverage                      Photomultipliers

•   225 Veto 20‖ PMT's from K-II
         Water Cherenkov
Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   Why Kamioka?




                              m 2 [eV 2 ] L[m] 
Pn e n m     sin 2 sin 
                    2
                           1.27 2
                                                  
                                E [MeV]         

  With L  175 km, E  5 MeV
                             5                    51 reactors in Japan,
  Sensitive to m  
                                                             LMA
                 2
                      2 175,000 1.27 
                                                     80% of flux (or 68.5 GW of
                                                       reactor power) from
                    4 10 5 eV 2                     baseline of ~140 to 210 km
Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   KamLAND Construction

   Autumn 1999                             Steel sphere construction
   Summer 2000                             PMT installation
   Winter 2000                             Veto counter installation
   February 2001                           Balloon insertion
   April-May 2001                          Plumbing for fill
   June-Sept. 2001                         Mineral oil and liquid scintillator fill
   Early Sept. 2001                        Electronics/DAQ integration
   Late Sept. 2001                         First data taking
   Jan. 22, 2002                           Production data taking began
   Dec. 6, 2002                            First paper submitted


Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   Position Reconstruction Uncertainty

                                                      68Ge: 1.012 MeV (g + g)
                                                      65Zn: 1.116 MeV (g)
                                                      60Co: 2.506 MeV (g + g)
                                                      AmBe: 2.20, 4.40, 7.6 MeV (g)
                 FV                                   -5 m                            +5 m




  Position resolution ~ 25 cm.
  Vertex reconstruction based on photon arrival times.
Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   Energy Calibration


                              65Zn

                              (1.115 MeV g)




                                                      • Esyst = 1.91% at 2.6 MeV
       60Co                                                   2.13% for ne
       (2.505 MeV g+g)
                                                      • E/E ~ 7.5% /√E

                                                      • Energy varies by < 0.5% within
                                                      fiducial volume of R < 5m
     Light yield ~ 300 p.e./MeV
Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   Radioactive Background
                                                      Requirements for reactor ne detection
                                                             238U 232Th ~ 10-14 g/g
                                                                40K ~ 10-15 g/g




Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
     Reactor Anti-Neutrino Flux Analysis
                                                       Data Sample    Mar. 4 – Oct. 6, 2002
            ne  p  n e 
                                     prompt                           162 ton•yr (145.1 days)
      delayed                         e  e   2g                   ~ 370M raw events
           n  p d  g (2.2 MeV)
                                                      Inverse b-decay selection

                                                          • no m veto signals
                                                        • Eprompt < 30 MeV
                                        g   from n12C
                                                        • 0.5 < T < 660 msec
                                                          • R < 1.6 m, Rd > 1.2 m
                                                          • 1.8 < Edelayed< 2.6 MeV
                                                          • R < 5 m : 409 ton, 3.46x1031 free
                                                          protons

                                                                tagging efficiency 78.3%


     Fitted correlation time between prompt and delayed sub-event:
     t=188 ± 23 ms  In agreement with expectation for thermal n-capture.

 Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   Reactor Anti-Neutrino Flux Results
  Eprompt > 2.6 MeV (to remove geo-n)

 Observed             54 events                                   Systematic Uncertainties
                                                      Detector related      %     Source related      %
 Expected              86.8 ± 5.6 events              Total LS mass         2.1   Reactor power      2.0
                                                      Fiducial mass ratio   4.1   Fuel composition   1.0
 Background 1 ± 1 events
                                           Energy threshold                 2.1   Time lag           0.28
             [accidental 0.0086 ± 0.0005
              9Li/8He      0.94 ± 0.85     Cut efficiency                   2.1   %v spectra         2.5
              fast neutron < 0.5         ] Live time                        0.7   Cross section      0.2
                                                      Total                                          6.4%


              Nobserved – NBKG
                Nno oscillation = 0.611 ± 0.085 (stat) ± 0.041 (syst)


Probability that result is consistent with no oscillation hypothesis < 0.05%

Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   Reactor Anti-Neutrino Flux
           Nobserved – NBKG
             Nno oscillation = 0.611 ± 0.085 (stat) ± 0.041 (syst)

                                                      First observation of reactor
                                                      anti-neutrino deficit
            Nobs/Nno oscillation




                                                                          LMA prediction:
                                                                    m2 = 5.5x10-5 eV2
                                                                    sin2 2 = 0.833




Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   Prompt Energy Spectrum



                                                      En(geo) < 2.49 MeV
                 Events/0.425 MeV




Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   Spectral Distortion?

           2-n oscillation: best-fit                  No oscillation, flux suppression




           Data and best oscillation fit                 Data and scaled no-oscillation
           consistent at 93% C.L.                        shape consistent at 53% C.L

                   Need more reactor neutrino and calibration data
Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   KamLAND: Summary
     KamLAND reactor antineutrino experiment (1st phase)

     • KamLAND detector is routinely taking data since January 2002.

     • Detector background and energy resolution are better than expected.

     • Analysis of first 145 days of data shows clear event deficit.
       After 50 years, first evidence for reactor ne disappearance.

     • Data taking continues.  Probe spectral deformations and perform
     precision measurement of neutrino mixing parameters.


     KamLAND 7Be solar neutrino and geo-neutrino experiment (2nd phase)
     • Will require lower backgrounds, possibly purification and re-circulation
     of scintillator and buffer oil
     • R&D effort underway at Tohoku U.



Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   2-n Mixing Paremeters


 Rate + Shape (>2.6 MeV)

 Best Fit:
 m2 = 6.9 x 10-5 eV2
 sin2 2 = 1.0

 Rate + Shape (>0.9 MeV)
 fit with the additional free
 parameters of geo-
 neutrino backgrounds
 are consistent with the
 results above




Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   What will SNO and KamLAND tell us in the future?




                                                      de Holanda et al., hep-ph/0212270
Alan Poon, I.O.P HEPP Particle Physics 2003, Durham   Barger et al., hep-ph/0204253
   Summary




  • Solar Neutrino Problem solved, and
    much have been learned about neutrino
    mixing


            Stay Tuned…More have yet to come!


Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
                    The SNO Collaboration
                                                                  J.D.Anglin, M.Bercovitch, W.F.Davidson, R.S.Storey*
                                                                  National Research Council of Canada
 G.Milton, B.Sur
 Atomic Energy of Canada Ltd., Chalk River Laboratories
                                                                  J.C.Barton, S.Biller, R.A.Black, R.J.Boardman, M.G.Bowler,
                                                                  J.Cameron, B.T.Cleveland, X.Dai, G.Doucas, J.A.Dunmore,
 S.Gil, J.Heise, R.J.Komar, T.Kutter, C.W.Nally, H.S.Ng,
                                                                  A.P.Ferarris, H.Fergani, K.Frame, N.Gagnon, H.Heron, N.A.Jelley, A.B.Knox,
 Y.I.Tserkovnyak, C.E.Waltham
                                                                  M.Lay, W.Locke, J.Lyon, S.Majerus, G.McGregor,
 University of British Columbia
                                                                  M.Moorhead, M.Omori, C.J.Sims, N.W.Tanner, R.K.Taplin,
                                                                  M.Thorman, P.M.Thornewell, P.T.Trent, N.West, J.R.Wilson
 J.Boger, R.L Hahn, J.K.Rowley, M.Yeh
                                                                  University of Oxford
 Brookhaven National Laboratory
                                                                  E.W.Beier, D.F.Cowen, M.Dunford, E.D.Frank, W.Frati,
 R.C.Allen, G.Bühler, H.H.Chen*
                                                                  W.J.Heintzelman, P.T.Keener, J.R.Klein, C.C.M.Kyba, N.McCauley,
 University of California, Irvine
                                                                  D.S.McDonald, M.S.Neubauer, F.M.Newcomer, S.M.Oser, V.L Rusu,
                                                                  R.Van Berg, P.Wittich
 I.Blevis, F.Dalnoki-Veress, D.R.Grant, C.K.Hargrove, I.Levine,
                                                                  University of Pennsylvania
 K.McFarlane, C.Mifflin, V.M.Novikov, M.O'Neill, M.Shatkay,
 D.Sinclair, N.Starinsky
                                                                  R.Kouzes
 Carleton University
                                                                  Princeton University
 T.C.Anderson, P.Jagam, J.Law, I.T.Lawson, R.W.Ollerhead,
                                                                  E.Bonvin, M.Chen, E.T.H.Clifford, F.A.Duncan, E.D.Earle,
 J.J.Simpson, N.Tagg, J.-X.Wang
                                                                  H.C.Evans, G.T.Ewan, R.J.Ford, K.Graham, A.L.Hallin,
 University of Guelph
                                                                  W.B.Handler, P.J.Harvey, J.D.Hepburn, C.Jillings, H.W.Lee,
                                                                  J.R.Leslie, H.B.Mak, J.Maneira, A.B.McDonald, B.A.Moffat,
 J.Bigu, J.H.M.Cowan, J.Farine, E.D.Hallman, R.U.Haq,
                                                                  T.J.Radcliffe, B.C.Robertson, P.Skensved
 J.Hewett, J.G.Hykawy, G.Jonkmans, S.Luoma, A.Roberge,
                                                                  Queen’s University
 E.Saettler, M.H.Schwendener, H.Seifert, R.Tafirout, C.J.Virtue
 Laurentian University
                                                                  D.L.Wark
                                                                  Rutherford Appleton Laboratory, University of Sussex
 Y.D.Chan, X.Chen, M.C.P.Isaac, K.T.Lesko, A.D.Marino,
 E.B.Norman, C.E.Okada, A.W.P.Poon, S.S.E Rosendahl,
                                                                  R.L.Helmer, A.J.Noble
 A.Schülke, A.R.Smith, R.G.Stokstad
                                                                  TRIUMF
 Lawrence Berkeley National Laboratory
                                                                  Q.R.Ahmad, M.C.Browne, T.V.Bullard, G.A.Cox, P.J.Doe,
 M.G.Boulay, T.J.Bowles, S.J.Brice, M.R.Dragowsky,
                                                                  C.A.Duba, S.R.Elliott, J.A.Formaggio, J.V.Germani,
 M.M.Fowler, A.S.Hamer, A.Hime, G.G.Miller,
                                                                  A.A.Hamian, R.Hazama, K.M.Heeger, K.Kazkaz, J.Manor,
 R.G.Van de Water, J.B.Wilhelmy, J.M.Wouters
                                                                  R.Meijer Drees, J.L.Orrell, R.G.H.Robertson, K.K.Schaffer,
 Los Alamos National Laboratory
                                                                  M.W.E.Smith, T.D.Steiger, L.C.Stonehill, J.F.Wilkerson
Alan Poon, I.O.P HEPP Particle Physics 2003, Durham               University of Washington
                 The KamLAND Collaboration

  K.Eguchi, S.Enomoto, K.Furuno, J.Goldman, H.Hanada,           P.W.Gorham, J.G.Learned, J.Maricic, S.Matsuno,
  H.Ikeda, K.Ikeda, K.Inoue, K.Ishihara, W.Itoh, T.Iwamoto,     S.Pakvasa
  T.Kawaguchi, T.Kawashima, H.Kinoshita, Y.Kishimoto,           University of Hawaii
  M.Koga, Y.Koseki, T.Maeda, T.Mitsui, M.Motoki, K.Nakajima,
  M.Nakajima, T.Nakajima, H.Ogawa, K.Owada, T.Sakabe,           S.Dazeley, S.Hatakeyama,M.Murakami, R.C.Svoboda
  I.Shimizu, J.Shirai, F.Suekane, A.Suzuki, K.Tada, O.Tajima,   Louisiana State University
  T.Takayama, K.Tamae, H.Watanabe
  Tohoku University                                             B.D.Dieterle, M.DiMauro
                                                                University of New Mexico
  J.Busenitz, Z.Djurcic, K.McKinny, D-M.Mei, A.Piepke,
  E.Yakushev                                                    J.Detwiler, G.Gratta, K.Ishii, N.Tolich, Y.Uchida
  University of Alabama                                         Stanford University

  B.E.Berger, Y.D.Chan, M.P.Decowski, D.A.Dwyer,
  S.J.Freedman, Y.Fu, B.K.Fujikawa, K.M.Heeger,                 M.Batygov, W.Bugg, H.Cohn, Y.Efremenko,
  K.T.Lesko, K.-B.Luk, H.Murayama, D.R.Nygren,                  Y.Kamyshkov, A.Kozlov, Y.Nakamura
  C.E.Okada, A.W.P.Poon, H.M.Steiner, L.A.Winslow               University of Tennessee
  UC Berkeley/ Lawrence Berkeley National Laboratory
                                                                L.DeBraeckeleer, C.R.Gould, H.J.Karwowski,
                                                                D.M.Markoff, J.A.Messimore, K.Nakamura, R.M.Rohm,
  G.A.Horton-Smith, R.D.McKeown, J.Ritter, B.Tipton, P.Vogel
  California Institute of Technology                            W.Tornow, A.R.Young
                                                                Triangle Universities Nuclear Laboratory
  C.E.Lane, T.Miletic
  Drexel University                                             Y-F.Wang
                                                                IHEP, Beijing
Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
         SNO
         Backup Slides


Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
Radioactive Backgrounds
   Daughters in U or Th chain
      • bdecays
      • bg decays

   ―Photodisintegration‖ (pd)
   g+dn+p
   Indistinguishable from NC !
   Technique:  Radiochemical assay
                     Light isotropy


   ―Cherenkov Tail‖
   Cause:  Tail of resolution, or
           Mis-reconstruction
   Technique:  U/Th calib. source
               Monte Carlo                           Must know U and Th
                                                      concentration in D2O

Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
 Radioactive Backgrounds (SNO Phase I)
   I. Ex-situ (Radiochemical Assays)
   • Count daughter product decays:
      224Ra, 226Ra, 222Rn


   II. In-situ (Low energy physics data)
   • Statistical separation of 208Tl and
       214Bi using light isotropy




Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
  Low E Background Summary
       For Te 5 MeV,            pd neutron bkg.                   Tail Bkg
       R<550cm                          (counts)                   (counts)
                                            8                          13
       D2O                               44 9            D2O         206
       H2O+AV                               8                           4
                                         27 8            H2O           33
       Atmospheric n
                                       4 1             AV             3
                                                                        66
                                                           
                                                                          11
       235U   spont. fission              1             PMT          16 8
                                                          
                                                                        17
       2H(a,a)pn
                                    2.0  0.4           Total       4511
                                                            
       17O(a,n)
                                        1
                                                             
                                                         [c.f.: 2928 n candidates]
       Terrestrial &                       3
       reactor n
                                        11              
                                                      12% of the number of
       External neutrons                1         observed NC neutrons
                                                      assuming standard solar
       Total                              78 ± 12   model n flux
                                 
Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   How Will the Salt Be Removed?
                                  How Will the Salt Be Removed?
               The current run plan is to
               obtain 9 - 12 months of
               livetime prior to salt removal.
               • Salt will be removed using a
               reverse osmosis unit, which
               will produce a concentrated
               brine.
               • The target is for ~1ppm salt
               in the D2O after multiple                  SNO’s reverse osmosis unit
               passes through the unit.
               •At this level salt will not           Once the salt has been removed, SNO
               significantly affect neutron           plans to continue with a short pure D2O run
                                                      before entering the third phase of neutral
               capture in the heavy water
                                                      current detection, when an array of 96 3He
               region.
                                                      proportional counters will be installed into
                                                      the detector.

Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   Data Reduction

          Nov 2, 1999 to May 28, 2001
          306.4 live days  “Day” = 128.5 days, “Night” = 177.9 days

                 Analysis Step                            Events
                 Total Event Triggers                 450,188,649
                 Neutrino Data Trigger                191,312,560
                 NHIT •30                              10,088,842
                 Instrumental Background                7,805,238
                 Cherenkov "likelihood"                 3,418,439
                 Fiducial Volume (R<550cm)                 67,343
                 Energy Threshold (T>5 MeV)                  3440
                 Residual Cosmic Background                  2928
                 Candidate Event Set                        2928


Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   Data Reduction Cuts




                                                        Light isotropy measure
   Remove instrumental
   background (e.g. PMT
   “flasher” using):

   • PMT time & charge distribution
   • Event time correlation
   • Veto PMT tag
   • Reconstruction information
   • Light isotropy & arrival timing
                                                                                        Light arrival timing
                          0.39                                0.40             0.41
  n signal loss: CC : 1.430.21 %                     ES : 1.460.21 % NC : 2.28 0.23%

  Residual instrumental bkg. contamination:                                      < 3 events (95% CL)

          
Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   Event Reconstruction

     Given:
     Hit PMTs’ positions & timing




     Determine event’s: (x,y,z) & (,f)



         Fiducial                    Separation                            fCC/fCC fNC/fNC
         volume                   of n signals from                         2.9        1.8
                                                      Vertex Acc uracy             %      %
      determination                  background                             2.8     1.8
        (Ntarget=?)                                                         0.0     0.1
                                                      Vertex Resolution          %        %
                                                                            0.0     0.1
                                                                           0.2      0.3
        Tools: Triggered g and b sources              Angular Resolution        %       % 
                                                                           0.2      0.3
                                                                           2.9 1.8      
                                                      Total                        %           %
                                                                           2.8         1.8
                                                                                                 
Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   Neutron Calibration
                                                      Response vs 252Cf source position
  • Calibrate using 252Cf fission source
  (~3.8 n per fission)


             Capture Efficiency

  Total:                         29.90 ± 1.10 %

  With energy                    14.38 ± 0.53 %
  threshold &
  fiducial volume
  selections
  (T>5 MeV, R<550 cm)




Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   CC, ES, NC Flux




               fCC (n e )  1.76 0.05 (stat.) 0.09 (syst.)10 6 cm2s 1
                                             0.06    0.09



               fES (n x )  2.39 0.23 (stat.) 0.12 (syst.)10 6 cm2s 1
                                 0.24         0.12



               fNC (n x )  5.09 0.43 (stat.) 0.46 (syst.)10 6 cm2s 1
                                 0.44
                                               0.43





Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   KamLAND Backup Slides




  KamLAND
  Backup Slides


Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   A Candidate Anti-n Event


                              (colour is time)




                 Prompt Signal                        t = 111 ms   Delayed Signal
                  E = 3.20 MeV                        R = 34 cm     E = 2.22 MeV

Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   Front End Electronics
                                                Waveforms are recorded using Analogue
                                                Transient Waveform Digitizers (ATWDs),
                                                allowing multi p.e. resolution

                                                  ADC
                                                  Counts




                                                           raw data
     The ATWDs are self launching                         pedestal
                                                           pedestal subtracted
    with a threshold ~1/3 p.e.

     Each PMT is connected to 2 ATWDs,
    reducing deadtime
                                                                                 samples (~1.5ns)
     Each ATWD has 3 gains (20, 4, 0.5),
    allowing a dynamic range of ~1mV- ~1V

Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   Waveform Digitiser

     Have full waveform
     digitizers on every central
     and veto channel
                                                        1 p.e.




     Data from blue LED
     flashers in the detector




     Important for exploring new                     2 p.e.
    physics and reject complex
    background signatures

Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   Reactor Anti-Neutrinos
  Fission:
   ~200 MeV / fission (―power‖)
     • Thermal power is routinely
        measured by the reactor operator
        in order to adjust the reactor to
        the highest licensed power.
        Economics ($$) pushes this error
        to ~0.6-0.7%
   ~6 n/ fission (―f& spectrum‖)
     • 240Pu & 242Pu: negligible
        • 235U, 239Pu, 241Pu n spectrum
        derived from b spectroscopy
        [Schreckenback et al., Phys. Lett B160 (1985) 325
        Hahn et al., Phys. Lett. B218 (1989) 365]


        • 238U n from fast-n fission, and
        has to be derived from 1st
        principles: 1000 channels
        (uncertainty~10%), but n yield
        from 238U is only 11% of total 
        total uncertainty due to 238U ~1%
Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   Source Spectrum



                                                      Goesgen




 ―Standard‖ anti-neutrino spectral determination
 procedures checked with short base-line reactor
 anti-neutrino experiments
Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   Introduction to KamLAND
    KamLAND follows the long history
     of using reactor anti-neutrinos to  Spectral distortions if ne oscillate
      investigate neutrino properties    Suppressions ~ factor of 2




  Reactor
ne spectrum                    Cross section for
                                n e + p  e+ + n
Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
Time Variations of Reactor Power and Signals




Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   Radioactivity Inside Scintillator




Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   Muon-Induced Backgrounds

                                                      L < 3m




                       12B
                 12N




     Test energy scale at higher energies.
Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   85Kr        Background
  85
    Kr coincidence measurement




 Dominant low-energy backgrounds:
          • 85Kr (Q=687 keV)
          • 210Pb, 210Bi (from Rn decays)

We are working on purification to remove such contamination for
detector upgrades for 7Be solar n program
Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   Accidental Background

      Ep>2.6 MeV                 in delayed time window of 0.2-20 s




    Accidental bkgd:
    0.0086  0.0005




Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
Vertex Distributions of neutrons & 12B/12N

    Fiducial Volume Studies




                                        V/V = 4.06 %


                                                        Vfid/Vfid = 4.6 %


Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   Statistical Analysis of Mixing Parameters
    Rate-only Analysis

                                             0.611Ratio (m , sin 2 )
                                                                                 2
                                                                   2     2

                                   c   2
                                           
                                                      0.085 2  0.0412
     c2 in (m2, sin22) space. Points with c 2  3.84 (95% CL) are excluded.

                  

      Spectral+Rate Analysis
                                         2
                                                  (
                                 c 2  c Rate m 2 , sin 2 2 ,N BG , a     )       (Rate)

                                                      (
                                     2 logLshape m 2 , sin 2 2 ,N BG , a      )   (Shape)
                                       c BG (N BG )  cdistortion (a )
                                         2             2
                                                                                     (Bckgrd)

      c2 in (m2, sin22) space. Points with c 2  5.99 (95% CL) are excluded.
Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   General n Background Slides




      General n Backup
      Slides



Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   Remaining Questions…

  • n: Dirac or Majorana
  • Absolute n mass scale
  • 13
  • CP violation in leptonic sector?
  • n Mass hierarchy
  • Verify oscillation (strong evidence, no direct
    observation yet)
  • LSND? Sterile n? CPT violation?


Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   Neutrino Mixing

         The general lepton mixing matrix (Maki-Nakagawa-Sakata-
         Pontecorvo) is expressed as

                            e
                            n              e 1 U e 2 U e 3
                                             U                      n 1   
                                                                    
                            n
                            m           m 1 U m 2 U m 3
                                             U                       n
                                                                       2    
                                                                    
                            n
                                         1 U  2 U  3
                                             U                       n
                                                                       3    
         The Standard Electroweak Model assumes U=I


                                              


Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
     Neutrino Mixing: What do we “know” now?
                                                                      1  0     0 
       1    0                   0                                             
                                               Atmospheric n       0 1/ 2 1/ 2 
                                                                      
 Uai = 0 cos  23            sin  23                                        
       
         sin  23
         0
                                        
                               cos  23                              1/ 2 1/ 2 
                                                                       0

            cos                                                                      0 e idCP sin  13 
                                 0 e    sin  13 
                                       idCP               Reactor
                                                                      
                                                                             ~1
                                                                                                             
                   13
                                                 
                 0             1     0         
                                                           (CHOOZ)          0           1        0         
            idCP sin                                               idCP sin                          
            e
                        13     0   cos  13  
                                                                       e
                                                                                   13   0        ~1        

           cos  12    sin  12    0                              0.85 0.51 0 
                                                   Solar n LMA                
            sin  12
                       cos  12    0                               0.51 0.85 0 
                                                                      
                                                                              
            0             0        1                               0     0  1


     Present “thinking”:                                      n e  0.85 n 1  0.51 n 2
                                                            
                                      n m  n                n m  0.36 n 1  0.60 n 2  0.71n 3
     Solar ne mix with                         2              n   0.36 n 1  0.60 n 2  0.71n 3

 Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   MNSP vs CKM
           Contrast between UCKM (quark) and UMNSP (lepton)

                     1                             1                          
                         (1O(  ))                     (1O (  ))        e 
                     2                              2                         
   U MNSP      
                 
                      1
                           (1O(  )  e )
                                                 1
                                                      (1O (  )  e )
                                                                             1     ~0.2 and e < 0.25
                    2                          2                            2 
                   1                           1                           1 
                        (1O(  )  e )                (1O (  )  e )      
                   2                            2                           2 


                  1     O(  ) O ( 3 ) 
                                        
     UCKM       O(  )  1     O (  ) 
                                      2

                  3 ) O( 2 )
                  O(                1 
                                        

       What is the underlying symmetry (possibly at GUT scale)?

Alan Poon, I.O.P HEPP Particle Physics 2003, Durham
   Future Solar n Experiments




                                                      Nakahata (LowNu2002 Conference)


Alan Poon, I.O.P HEPP Particle Physics 2003, Durham

								
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