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Report to SNOLAB2009

Report to SNOLAB2009. Chris Jillings on behalf of the DEAP-1 team. Timeline. July 4, 2008 Fill Gen 1 clean chamber Topup: Radon spike Background studies Jan 2009 - March 2009 Emanation measurements Improved design/manufacture of chamber March 19, 2009 Fill Gen 2 clean chamber

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Report to SNOLAB2009

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  1. Report to SNOLAB2009 Chris Jillings on behalf of the DEAP-1 team DEAP-1 for SNOLAB2009

  2. Timeline • July 4, 2008 Fill • Gen 1 clean chamber • Topup: Radon spike • Background studies • Jan 2009 - March 2009 • Emanation measurements • Improved design/manufacture of chamber • March 19, 2009 Fill • Gen 2 clean chamber • Radon trap • Install new DAQ • Strike • PSD running • Background studies • Future DEAP-1 for SNOLAB2009

  3. Improvements Since October 2008 • Backgrounds Reduced Factor of 10 • And much better understood • DAQ/Electronics • Installed by TRIUMF team (F. Retiere/P.-A. Amaudruz) • Throughput ~x10 higher • Using hardware that will be used for DEAP-3600 • PSD improved DEAP-1 for SNOLAB2009

  4. Zfit Calibration Zfit is a calibrated measure of position in the detector. DEAP-1 for SNOLAB2009

  5. Background Rates 10 0 July 4, 2008 Run 2-3 mHz steady state Top-up added large 222Rn spike Used to develop U-chain tags DEAP-1 for SNOLAB2009

  6. Emanation Measurement DEAP-1 for SNOLAB2009

  7. Emanation Measurement • While warm treated DEAP-1 as emanation chamber • Pumped to high vacuum • Allowed to emanate for many days • 134 +/- 19 Rn emanated/day • Repeated measurement with DEAP-1 chamber removed and blanked off: 6 +/- 4 Rn atoms/day • Also did background (“zero exposure”) emanations. • Emanation results consistent with all Radon coming from chamber. • Emanation of reflective paint at Queen’s was equal within error to emanation from all chamber. DEAP-1 for SNOLAB2009

  8. Generation I: 2008 Produced in glovebox Sanded surfaces ~20 particles/cm2 left on acrylic From 175 to 78000 mBq/kg U depending on brand/batch 0.01 to 3 mBq Rn in DEAP-1 TPB on inner surface <4 mBq/kg U/Th Exposure during evaporation ~4 bgnd events/year Sealing of vacuum vessel Possible admission of Rn in shipping Generation II: 2009 Improved glovebox/Rn monitoring Sanding Improvements Used clean sandpaper High-pressure rinse inside glove box As before As before Vacuum chamber was leak tested in glove box and filled with Rn-free air. Improvement Details DEAP-1 for SNOLAB2009

  9. Generation I: 2008 3 failed fills allowing unknown quantity air into DEAP-1 Radon in argon during fill Unknown how much gets through cooling coils Could have ~1 day exposure to high Radon loads Background analysis Offline, interpretations developed over weeks and months. Data show surface  rates measurable before fill Generation II: 2009 Procedures improved. Venting through bubblers Last fills and top-ups worked Radon filter in DEAP-1 Cold carbon trap Rn just above Argon boiling point Prototype built. Tested. Installed prototype for Mar16 fill Near-Online and Automatic Analysis Improvement Details (2) DEAP-1 for SNOLAB2009

  10. Radon Filter Prototype charcoal filter operating temperature -110C. No measurable Rn punch through in tests at Queen’s. Used for March 19 fill. Similar but larger device to be used on DEAP-3600. DEAP-1 for SNOLAB2009

  11. Background Rates July 4, 2008 Run 2-4 mHz steady state Top-up added large 222Rn spike Used to develop U-chain tags March 19, 2009 Run 0.2 to 0.4 mHz No initial spike DEAP-1 for SNOLAB2009

  12. U Chain: 222Rn and short-lived daughters Model: 222Rn and 218Po decay in LAr (100% eff detection). 214Po is on surface (50% eff det). DEAP-1 for SNOLAB2009

  13. Th Chain: 220Rn to 216Po to 212Pb t<1s Seen at correct  energy with same z position in detector 30 events in 236 hrs (Mar 19 run) DEAP-1 for SNOLAB2009

  14. Thorium Chain: 212BiPo (300 ns) DEAP-1 for SNOLAB2009

  15.  Backgrounds 10 days livetime Rate from coincidence tag (40 events each of 222Rn + 220Rn) DEAP-1 for SNOLAB2009

  16. Backgrounds in DEAP-1 Current background rate in ROI (120-240 pe) is 0.15 mHz Need absolute background of < 2 nHz for DEAP-3600, or 2 micro-Hz before position reconstruction for surface events DEAP-1 for SNOLAB2009

  17. Backgrounds • Clear evidence for Rn from U and Th chain based on alpha-coincidence tags • Improving calibrations of light yields in TPP. • To improve understanding of all alpha events below full-energy (in Argon) alpha peaks. • This could include 210Po (daughter of 210Pb). DEAP-1 for SNOLAB2009

  18. PSD Faster DAQ: >108 events in 22 days Data sets so far: 12x10-9 demonstrated 7x10-9 after analysis of all events on disk. DEAP-1 for SNOLAB2009

  19. Prototype of DEAP-3600 DAQ Linux computer • Installed and maintained by TRIUMF group. • Allows data rates of ~15 Mbytes/sec • ~600 events * 2 channels * 4000 12-bit samples/ch • CAEN V1720 WFD • MIDAS DAQ (well supported at TRIUMF) • Scalers to be implemented V1720 Struck scaler DEAP-1 for SNOLAB2009

  20. Future • DEAP-1 is our most sensitive tool for understanding backgrounds. • We are using DEAP-1 as a test bench for process systems and to measure activities in acrylic surfaces and TPB. • We are using DEAP-1 to prototype and test electronics and DAQ. • We are requesting to run DEAP-1 at SNOLAB for the next 2 to 3 years. We understand that a relocation may be necessary. DEAP-1 for SNOLAB2009

  21. end DEAP-1 for SNOLAB2009

  22. Scientists who have worked u/g on DEAP1 Mark Boulay1, Bei Cai1,Jeff Lidgard1,Ian Lawson2, Kevin Graham3, Fraser Duncan2, Chris Jillings2, Paradorn Pasuthup1, Noel Gagnon2, Peter Skensved1, Ueshima Kota4, Hugh Lippincott7, Kiyoshi Masui1, Luc Gatien2, Rafael Hakobyan5, Kevin Olsen5, Shawn Ligocki1, Takashi Iida4, Shawn Compton3, Victor Golovko1, Cameron Hurst1, Michael Ronquest6, Reyco Henning6, Perry Young1, Zach Fairchild2, Brian Wong2, TJ Robotham2, Bruce Cleveland2, Eoin Odwyer1, Oleg Chekvoretz2, Eric Vazquez2,Marcin Kuzniak1, Fabrice Retiere8,Pierre-Andre Amaudruz8, Rob Bark2, Corina Nantais1, Aline Trosset1, Berta Beltran5, 1: Queen’s 2: SNOLAB 3: Carleton 4: ICRR/Honda Canada Fellow 5: U. Alberta 6: U.N.C. 7:Yale 8: TRIUMF PhD,Graduate Student, Undergraduate student or degree DEAP-1 for SNOLAB2009

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