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Overview: Phased approach and scientific reach Funding and schedule Experimental layout and detailed infrastructure ne

Majarana double beta decay program. Overview: Phased approach and scientific reach Funding and schedule Experimental layout and detailed infrastructure needs Change in strategy and schedule given LAr option. Peter Doe, on behalf of the Majorana collaboration.

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Overview: Phased approach and scientific reach Funding and schedule Experimental layout and detailed infrastructure ne

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  1. Majarana double beta decay program • Overview: • Phased approach and scientific reach • Funding and schedule • Experimental layout and detailed infrastructure needs • Change in strategy and schedule given LAr option Peter Doe, on behalf of the Majorana collaboration SNOLab-Majarana Aug. ‘05

  2. Phased approach and scientific reach • Scalable  3 phases: M180… 180 kg, 86% enriched 76Ge, 60 kg 120 kg 180 kg “conventional” technology m≥ 120 meV (degenerate hierarchy) M500/M1000…500-1000 kg, LAr/LN2 collaboration with GERDA? m≥ 50 meV (inverted hierarchy) MX000… Technology unknown? m≥ 10 meV (normal hierarchy) SNOLab-Majarana Aug. ‘05

  3. Possibility of early activity U/G in FY-06 Funding from Majorana institutional support No federal funding before FY-07 Funding Expect NuSAG response at end of August ?  SNOLab-Majarana Aug. ‘05

  4. 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 R&D Module Construction Enriched Ge 1st 60 kg running 2nd 60 kg running 3rd 60 kg running M180 Operating Phase Schedule SNOLab-Majarana Aug. ‘05

  5. 57 crystal module (60 kg) Conventional vacuum cryostat made with electroformed Cu. Three-crystal stack are individually removable. Vacuum jacket Cap Cold Plate Tube (0.007” wall) Cold Finger Ge (62mm x 70 mm) 1.1 kg Crystal Tray (Plastic, Si, etc) Thermal Shroud Bottom Closure 1 of 19 crystal stacks Majorana modular approach SNOLab-Majarana Aug. ‘05

  6. Allows modular deployment, early operation contains up to eight 57-crystal modules (M180 populates 3 of the 8 modules) four independent, sliding units 40 cm bulk Pb, 10 cm ultra-low background shield active 4 veto detector Veto Shield Sliding Monolith LN Dewar Inner Shield 57 Detector Module Majorana shield - conceptual design Top view SNOLab-Majarana Aug. ‘05

  7. Experimental layout/infrastructure - M180 • Three areas of underground activity: • Fabrication Electroforming copper parts • Assembly Putting it together Making it work • Data taking - staged by module 60 kg  120 kg  180 kg SNOLab-Majarana Aug. ‘05

  8. Layout - Fabrication areas Dimensions in meters SNOLab-Majarana Aug. ‘05

  9. Layout - Detector area Dimensions in meters SNOLab-Majarana Aug. ‘05

  10. Low background electroformed copper Electroformed cold finger and signal wires for MEGA Mass, M180 copper components 2 crystal thermal shroud, 250 mm wall thickness SNOLab-Majarana Aug. ‘05

  11. Electroforming copper - key elements Electroforming copper C C A A B B CuSO4 • Semiconductor-grade acids • Copper sulfate purified by recrystallization • Baths circulated with continuous microfiltration to remove oxides and precipitates • Continuous barium scavenge removes radium • Cover gas in plating tanks reduces oxide formation • Periodic surface machining during production minimizes dendritic growth • H2O2 cleaning, citric acid passivation 232Th<8Bq/kg Current density ~ 40mA/cm2 Plating rate ~ 0.05 mm/hr SNOLab-Majarana Aug. ‘05

  12. Electroforming copper - Infrastructure • HEPA-filtered air supply • Radon-scrubbed air for lowest-level work • Fume extractor for etching • Flammable and hazardous gas sensors • Radon-proof storage lockers with purge gas and vacuum capability • Etching and acid storage • Spill containment lining • Milli-Q water system w/DI supply water • Air-lock entry, washable walls • Air-conditioning to ~ 20 C • 10-6 Torr dry vacuum system Cold plate for the MEGA feasibility study at WIPP, NM. SNOLab-Majarana Aug. ‘05

  13. Infrastructure (continued) SNOLab-Majarana Aug. ‘05

  14. M180 - Special considerations • Cryogens (1000 liters) • Waste gasses (electroforming, etching) • Acids (electroforming) • Solvents (alcohol, acetone…) • Oxidizers (dilute H2O2 cleaner) • Lead (shielding) • Flammable plastics (veto) • Compressed gasses • Radon-free inert cover gasses (LN2?) • Radioactive sources SNOLab-Majarana Aug. ‘05

  15. LAr option - strategy change and schedule Decision • 2 year LArGe R&D  • Crystal, light stability in Lar • Detector Monte Carlo studies • Detector design • Engineering design • Estimate 3m Ø cryogenic vessel (~20 ton LAr) • Requires underground fabrication of dewar ( schedule) • Less electroformed copper parts ( schedule) • Would not change enrichment schedule • Would not change staging plan (~60120180 kg) • Would need higher overhead clearance (≥8 m ?) SNOLab-Majarana Aug. ‘05

  16. Summary • Majorana is modular, 60120180 500X,000 kg • M180 employs demonstrated, “conventional” technology • Material purity is critical, but achievable • Significant underground fabrication, assembly • Optimistically, enrichment late 2007, first data 2009/10 • LAr option being investigated, little schedule impact(?) SNOLab-Majarana Aug. ‘05

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  18. Electroforming numbers Bath size: Cryostat 40 cm high x 40 cm  Tank 50cm x 75cm x 50cm 225 liters x 8 tanks 1800 liters Plating time: Cryostat 3mm / 0.05 mm hr-1 = 60 hr @50% efficiency, 12 hr/day = 10 days (2 weeks) Bath power: Cryostat Area =  x 202 x 40 = 5030 cm2 power = 5030 cm2 x 40 mA cm-2 2 kA Assume 4 kW/bath  32 kW total SNOLab-Majarana Aug. ‘05

  19. Cu parts count 54 bath weeks, 100% contingency, 8 baths  4 months electroforming @ 2 shifts/day, 5 days/week SNOLab-Majarana Aug. ‘05

  20. Plating Bath Process Parameters • Plating is done onto polished, cleaned, stainless steel mandrels in the shape of the desired parts • Current density is ~40 mA/cm2 • Plating rate is ~0.05 mm/h • BaSO4 collects in the micro-filtration stage and acts as radium scavenge • CoSO4 was added as a holdback carrier for the cosmogenic 56,57,58,60Co present in the starting copper • HCl and Thiourea affect copper crystal nucleation and grain size SNOLab-Majarana Aug. ‘05

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