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Assay and Acquisition of Radiopure Materials Priscilla Cushman University of Minnesota

Assay and Acquisition of Radiopure Materials Priscilla Cushman University of Minnesota LRT 2010, Sudbury Canada August 28-29. A ssay and A cquisition of R adiopure M aterials. Principle Investigators Priscilla Cushman (University of Minnesota)

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Assay and Acquisition of Radiopure Materials Priscilla Cushman University of Minnesota

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  1. Assay and Acquisition of Radiopure Materials Priscilla Cushman University of Minnesota LRT 2010, Sudbury Canada August 28-29

  2. Assay and Acquisition of Radiopure Materials Principle Investigators Priscilla Cushman (University of Minnesota) Dongming Mei (University of South Dakota) Kara Keeter (Black Hills State University) Richard Schnee (Syracuse University) Engineering Consortium CNA Consulting Engineers (Lee Petersen) Dunham Associates Miller Dunwiddie Architecture, Inc An NSF S4 (~ $1M) was awarded for these specific tasks • Characterize radon, neutron, gamma, and alpha/beta backgrounds at Homestake • Develop a conceptual design for a common, dedicated facility (FAARM) for low background counting and other assay techniques • Assist where appropriate in the creation of common infrastructure required to perform low background experiments. • Perform targeted R&D for ultra-sensitive screening and water shielding

  3. Assay and Acquisition of Radiopure Materials AARM is the Collaboration which includes members from many different experiments AARM seeks to organize cross-experimental identification, assay, and storage of radiopure materials for shielding and construction of detectors and shared nuclear and materials database Priority (S4) has been on designing the DUSEL FAARM = Facility for Assay and Acquisition of Radiopure Materials Organization of early screening and integration of multiple sites is focus of our next collaboration meeting: November 12-13 @ Sanford Lab LRT Discussion on same topic: Sunday at 4:20

  4. Broader Collaboration – open enrollment ! (http://zzz.physics.umn.edu/lowrad/collab) International Scientific Advisory Panel Laura Baudis (Zurich University)Richard Ford (Queen’s University, SNOLab) Gilles Gerbier (CEA Saclay)Gerd Heusser (Max Planck Institute, Heidelberg) Andrea Giuliani (University of Insubria (Como), Coordinator of ILIAS Continuation)Mikael Hult (European Commission: JRC Inst. for Reference materials and Measurements) Vitaly Kudryavtsev (University of Sheffield)Pia Loaiza (Laboratoire Souterrain de Modane) Matthias Laubenstein (INFN, Gran Sasso Laboratory)Neil Spooner (University of Sheffield) Scientific Collaboration Craig Aalseth Henning Back Tim Classen Jodi Cooley Darren Grant Yuri Efremenko Brian Fujikawa Reyco HenningJeff MartoffRobert McTaggart Esther Mintzer Andreas Piepke Andrew Sonnenshein John Wilkerson Tullis Onstott

  5. Design and Location of FAARM • Design Principles • Surface/Shallow Infrastructure • Easy access for less sensitive screening E&O projects, NAA HPGe, radiochemistry lab • New labs as needed (not in our “plan” – we will send samples out) ICPMS, surface characterization, atom trace analysis • Depends on the infrastructure in the surface campus • 4850-ft level FAARM • deep enough for ultra sensitive screening and dark matter prototype testing • close to experiments for easy access (drive in large items) • share water purification and cryogen infrastructure • unite functions under a dedicated staff • Need new approach to multi-user shielding: • individual lead shields too expensive and not radiopure • neutron shielding required for DM prototypes and Immersion tank • muon capture, activation, a-n/fission become important

  6. Elements of FAARM Entire facility is class 10,000 clean room, < 20 Bq/m3 Several class 1000 clean rooms Ateko (NEMO facility provided 0.01 Bq/m3 breathable air at 150 m3/h) Radon-mitigated zones (<1 Bq/m3) and assembly areas (<0.1 Bq/m3) Radon-free storage and unified LN system Wet benches, clean machining, hoods, etc Instrumented Water Shield with toroidal interior acrylic room Houses ultra-sensitive screeners (GeMPI style, BetaCages) Reduce cost of individual lead shielding ($2M savings) Active Muon veto, Neutron & Gamma shielding Outer shield of Immersion Tank, Space for Experiments & R&D Prototypes Top-loading Immersion Tank Modeled on the Borexino CTF Whole body counting with 0.1 counts/day, E > 250 keV U/Th at .01/.04 ppt, surface a,b at < 1 count/m2/day (unsealed) 6 x 10-6 cts/kg/keV/day from Compton continuum OPTION:Could be replaced by highly segmented germanium

  7. Elements of FAARM Served by a trained technical staff Develop staff in the Early Screening Program (DULBCF) Scheduling tools to optimize efficient use of screeners Integrate with worldwide screening In-house analysis tools and database Transition the screening in a phased manner Less sensitive screeners benefit from common facility outside shield but inside clean areaRadon emanation, XIA alpha screeners, conventional HPGe Areas for bio/geo/physics assembly Intellectual center for a new field of low background studies

  8. FAARM Elevation

  9. FAARM First Floor

  10. FAARM Second Floor

  11. FAARM Rendering

  12. FAARM Rendering

  13. FAARM Rendering

  14. Water Shield Simulations Optimize shield thickness Attenuation through Water + Stainless Steel Rock (Homestake 4850’) 238U 0.55 ppm 232Th 0.3 ppm 40K 2.21% gamma’s from rock radiogenic neutrons cosmogenic neutrons (tagged) X • Cavern radioactivityafter 2.3 m thick wall • 7.974×10-5 /cm2/s • n4.817×10-10 /cm2/s vs

  15. Detailed Geant4 studies will determine background levels design optimization materials choice support structures water purity PMT and QUPID placement active rejection light yield rejection efficiency Upgrade options: Gd-loading or LS shield • Villano (Minnesota)

  16. Borexino Counting Test Facility • 4 tonnes of scintillator (PC + 1.5 g/L PPO) • 1m radius 500μm Nylon vessel for scintillator • 2 m radius “shroud” vessel to shield Rn • 3.6 p.e./PMT for 1 MeV electron • Muon veto PMTs on floor • 100 PMTs (Optical coverage: 21%) • Buffer of water – 2.3m vessel to PMT • Energy saturation: 6 MeV

  17. CTF-like Immersion Tank for Screening • Water shield becomes outer shroud and veto • Low radioactivity QUPIDs can be placed closer to LS • Bigger 2 m diam. nylon bag filled with LAB Liq. Scint. • Established purification methods • (10-16 g/g U/Th andd 10-14 g/g K) • Distillation (also removes Rn) • Water extraction • N2 stripping • Solid-column adsorption 50% • Sensitive to • bulk gammas • betas and alphas from surface • betas inside 50 mm nylon sample bag • Moderate energy resolution & Efficiency • Distinguish • b:g via event reconstruction • a via pulse shape

  18. Schedule for FAARM Procurement and Assembly • Before Module is ready, but money is allocated • Detailed engineering-level design • Obtain bids, contracts and permits and hire contractor • Assemble and test water purification system • Procure radon system from Ateko (year lead time) • Choose photodetectors, screening and testing, bids • Purchase photodetectors, calibration and QA, electronics • Procure nylon and build dedicated clean room • Build nylon vessel in clean room • Once module is ready (Jan 2017) and radon < 100 Bq/m3 (ventilation, rock coating) • Install Ateko in module, operate temporary radon-free room for sensitive materials • Water tank assembly incl torus + civil + radon under direction of contractor • Ateko moved to final location inside FAARM • Beneficial occupancy one year later.

  19. Schedule for FAARM Installation and Commissioning After Beneficial Occupancy Establish moderate cleanliness protocols immediately after heavy construction Clean entire lab as soon as possible Clean and coat interior of shield, Install cables, plumbing, air, cryogen system Initial water fill and test plumbing – drain and clean Install Water Shield PMTs – fill shield, operate and calibrate PMTs Comission DAQ and shield – long muon run - drain Establish tight cleanliness protocol, including showers and radon mitigation Measure particulate level and radon to confirm – commission monitoring At least one sensitive HPGe moved to FAARM as bkgd monitor Install nylon vessel and QUPIDs (test and calibrate) Fill Immersion Tank with LS Install nitrogen blanket, clean room – Purity studies with QUIPIDs Fill shield – Combined Water + LS test and bkgd run Move other screeners in parallel with Immersion Tank commissioning

  20. FAARM Installation & Commissioning

  21. Created a Resource-loaded Cost & Schedule in Project. MREFC $$ Jan ‘14 Start of schedule Big Gap: 2010 – 2018 DUSEL ready Jan ‘17 Civil FinishedJan ‘18

  22. Need a Rational Plan until 2018 and how to transition to FAARM Sanford Lab does NOT have enough room in Davis, nor funds to purchase screeners Utilize existing underground sites and screeners until FAARM is ready Then - move the most sensitive screeners into FAARM shield collect less sensitive screeners as needed under one roof. Most important aspect of FAARM is the active SHIELD Shield transforms sensitive screeners into ultra-sensitive Central pool can house a 3rd generation screener Shield has been optimized for COST: ~ $200k per Screener + Shield for prototype experiments Move from model of dedicated screeners to a centrally managed system Determine needs for next decade Begin to build a coherent team and staff More efficient scheduling and new shared purchase schemes Find new sources of funding: EPSCOR, Sanford, University infrastructure …

  23. “Early Screening” to FAARM Transition • All screeners already bought, tested, and in operation from Early Screening era • Screening must continue with as few interruptions as possible • Staff is already in charge of all screeners, regardless of location • Each sensitive screener is commissioned at FAARM before the next one dismantled • Decommissioning effort (FTE) is flat over the year long transition • MILESTONE • 1/18 Beneficial Occupancy • 7/18 First GeMPI operational (Background Monitor) • 10/18 First Beta cage is screening at FAARM • Interleaved transfer schedule continues through the year • 1/19 All XIA alpha screening now at FAARM • 2/19 All GeMPIs, BetaCages now at FAARM *** Decommission Soudan LBCF • 3/19 All gamma screening at FAARM *** Release Davis cavern • 6/19 Whole body screening in Immersion Tank *** Fully operational FAARM

  24. Transitioning of Screening from multiple sites to FAARM Commissioning (detail)

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