1. Data Processing for the Sudbury Neutrino Observatory Aksel Hallin Queen’s, October 2006

2. Sudbury Neutrino Observatory 1700 tonnes Inner Shielding H 2 O 1000 tonnes D 2 O ($300 M) 5300 tonnes Outer Shield H 2 O 12 m Diameter Acrylic Vessel Support Structure for 9500 PMTs, 60% coverage Urylon Liner and Radon Seal

3. Unique Signatures in SNO (D 2 O) Charged-Current (CC) e +d  e - +p+p E thresh = 1.4 MeV e only e only Elastic Scattering (ES) x +e -  x +e - x, but enhanced for e Neutral-Current (NC) x + d  x + n+p E thresh = 2.2 MeV Equally sensitive to e   3 ways to detect neutrons

4. Numerical tools for SNO “Data Cleaning” Monte Carlo “Fitters” “Physics Interpretation”

5. Signal Extraction Reconstruction Physics interpretation

6. Observables -position -time -charge Reconstructed event -vertex -direction -energy -isotropy Photomultiplier tube

7. “Data Cleaning” TABLE II: Number of events remaining in data set after each step in the data processing described in Section 5.. Data Processing Step Events Remaining Total event triggers 450188649 Neutrino triggers (hit multiplicity) 191312560 Analysis Nhit cut (Nhit > 21) 10088842 Low-level cuts 7805238 `Cherenkov Box' cuts 3418439 Fiducial volume cut 67343 Energy threshold (Te > 5 MeV) 3440 Muon follower cut 2981 Atmospheric followers 2928 Total candidates 2928

8. Extracting the Solar Flux Maximum Likelihood Fit OR CC NCES PDFs: kinetic energy T, event location R 3, solar angle correlation cos  sun 8 B  shape constrained fit: [in 10 6 cm -2 s -1 ] No 8 B  shape constraint: Assumption: No 8 B shape distortion

9. Phase II (salt) July 01 - Sep. 03 Phase III ( 3 He) Nov. 04-Dec. 06 Phase I (D 2 O) Nov. 99 - May 01 3 Phases of SNO: neutron (NC) detection methods (systematically different) n captures on 2 H(n,  ) 3 H Effc. ~14.4% NC and CC separation by energy, radial, and directional distributions 40 proportional counters 3 He(n, p) 3 H Effc. ~ 30% capture Measure NC rate with entirely different detection system. 2 t NaCl. n captures on 35 Cl(n,  ) 36 Cl Effc. ~40% NC and CC separation by event isotropy 36 Cl 35 Cl+n 8.6 MeV 3H3H 2 H+n 6.25 MeV n + 3 He  p + 3 H p 3H3H 5 cm n 3 He

10. What does it mean to calibrate? Determine unknown parameters in the Monte Carlo. In SNO, these are almost all optical constants. Measure how well we reconstruct position, direction, energy, isotropy as a function of position in the detector and calendar time. In SNO, the calibration effort dominates the analysis. Typically 90% of the analysis effort is used to calibrate, measure backgrounds, and understand systematics; the signal extraction is quite standard. Improvements in the analysis come about because of improved calibration.

11. SNO Detector Livetime Phase III Livetime: Nov 27, 2004 to Nov 28, 2005 Dec 1/05 Mar 1/05 Jun 1/05 Sep 1/05Dec 1/05 RUN TYPE # OF DAYS PERCENTAGE ======================================== NEUTRINO 249.58 68.19 SUPERNOVA 0.14 0.04 CALIBRATION 89.26 24.39 OTHER 14.47 3.95 NO RUN 12.55 3.43

12. Calibration Source Manipulator Radon/Light Barrier Accuracy < 2 cm single axis ~ 5 cm triple axis Remote Operation/Interlocks Stringent Cleanliness Requirements UmbilicalsManipulationDetector Interface

14. 337,365,386, 420,500,620 nm wavelengths 45 Hz Pulse rate Intensity dynamic range about 1e7 600 ps pulse width

15. Optical Analysis Number of in-time hits in run i and pmt j = (Number of photons emitted in run i) x (solid angle of pmt j and run i) x (pmt angular response) x (transmssion through acrylic) x (laserball intensity distribution) x (efficiency of pmt j) x (transmission through water and acrylic) Remove unknown individual PMT efficiencies with “occratio” Typically 40 runs x 7000 pmts = 280,000 data points Fit for about 400 parameters:

16. Optical Analysis D 2 O AttenuationH 2 O Attenuation PMT calibrations, PMT angular response, D20, acrylic, H2O

17. PMT Angular Response

18. Swapped pmts- angle of rotation