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SuperCDMS at SNOLAB Wolfgang Rau, Queen’s University for the SuperCDMS Collaboration. CDMS / SuperCDMS Timeline. CDMS I 6 detectors 1 kg Ge (30 kgd ) < 3.5e-42 cm 2. 1998 - 2002. CDMS II (until 2009) 30 detectors ~4 kg Ge (300 kgd ) < 3.5e-44 cm 2. SUF, 10 mwe.
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SuperCDMS at SNOLAB Wolfgang Rau, Queen’s Universityfor the SuperCDMS Collaboration
SuperCDMS at SNOLAB – W. Rau – SNOLAB workshop 2010 CDMS / SuperCDMS Timeline CDMS I 6 detectors 1 kg Ge (30 kgd ) < 3.5e-42 cm2 1998 - 2002 CDMS II (until 2009) 30 detectors~4 kg Ge (300 kgd) < 3.5e-44 cm2 SUF, 10 mwe 2003 - 2013 SuperCDMS @ Soudan~20 detectors 10-15 kg Ge (~1200 kgd) < 9e-45 cm2 Soudan, 2100 mwe exposures areafter all cuts! SuperCDMS @ SNOLAB 80-90 detectors100 kg Ge (~35000 kgd) < 3e-46 cm2 2011 - 2017 SNOLAB, 6000 mwe SuperCDMS test facility @ SNOLAB (2011)
SuperCDMS at SNOLAB – W. Rau – SNOLAB workshop 2010 SuperCDMS Collaboration California Institute of TechnologyZ. Ahmed, J. Filippini, S.R. Golwala, D. Moore Fermi National Accelerator LaboratoryD. A. Bauer, F. DeJongh, J. Hall, D. Holmgren, L. Hsu, E. Ramberg, R.L. Schmitt, J. Yoo Massachusetts Institute of TechnologyE. Figueroa-Feliciano, S. Hertel, S.W. Leman, K.A. McCarthy, P. Wikus NIST *K. Irwin Queen’s UniversityC. Crewdson*, P. Di Stefano *, J. Fox *, S. Liu *, C. Martinez *, P. Nadeau *, W. Rau Santa Clara UniversityB. A. Young SLAC/KIPAC *M. Asai, A. Borgland, D. Brandt, W. Craddock, E. do Couto e Silva, G.G. Godrey, J. Hasi, M. Kelsey, C. J. Kenney, P. C. Kim, R. Partridge, R. Resch, J.G. Weisend, D. Wright Southern Methodist UniversityJ. Cooley Stanford UniversityP.L. Brink, B. Cabrera, M. Cherry *, R. Moffatt*, L. Novak, R.W. Ogburn , M. Pyle, M. Razeti*, B. Shank*, A. Tomada, S. Yellin, J. Yen* Syracuse UniversityM. Kos, M. Kiveni, R. W. Schnee Texas A&MK. Koch*,R. Mahapatra, M. Platt *, K. Prasad*,J. Snader University of California, BerkeleyM. Daal, T. Doughty* , N. Mirabolfathi, A. Phipps, B. Sadoulet,D. Seitz, B. Serfass, D. Speller*, K.M. Sundqvist University of California, Santa BarbaraR. Bunker, D.O. Caldwell, H. Nelson University of Colorado DenverB.A. Hines, M.E. Huber University of FloridaT. Saab, D. Balakishiyeva, B. Welliver* University of MinnesotaH. Chagani*, J. Beaty, P. Cushman, S. Fallows, M. Fritts, T. Hoffer*, O. Kamaev, V. Mandic, X. Qiu, R. Radpour*, A. Reisetter, A. Villano*, J. Zhang University of ZurichS. Arrenberg, T. Bruch, L. Baudis, M. Tarka * new collaborators or new institutions in SuperCDMS
SuperCDMS at SNOLAB – W. Rau – SNOLAB workshop 2010 Overview • CDMS Technology • SuperCDMS at Soudan • iZIP Detectors • SuperCDMS at SNOLAB • SuperCDMS Detector Test Facility at SNOLAB
SuperCDMS at SNOLAB – W. Rau – SNOLAB workshop 2010 Thermal bath Thermal coupling Phonon sensor e n + + + - - Target - Ionization energy [keVeeq] - + + - - + + - + + + + Phonon energy [keV] - - - - CDMS Technology • Phonon signal: measures energy deposition • Ionization signal: distinguishes between electron (large) and nuclear recoils (small) • Surface events have reduced ionization: need additional information to identify Electron recoils from β’s and γ’s Phonon signal Electron recoil Nuclear recoil Charge signal Nuclear recoils from neutrons
SuperCDMS at SNOLAB – W. Rau – SNOLAB workshop 2010 SuperCDMS at Soudan Detectors • New detectors: • larger mass (240 g 610 g), larger volume-to-surface ratio (x 2.5) • New phonon sensor design: mZIP improve position reconstruction and pulse shape discrimination for surface events • New electrode design: iZIP discriminate surface events based on charge distribution between electrodes • iZIPs have more readout channels per detector (both, phonon and charge sensors on top and bottom) than mZIPs fewer detectors, but larger fiducial volume/detector iZIP ZIP mZIP
SuperCDMS at SNOLAB – W. Rau – SNOLAB workshop 2010 SuperCDMS at Soudan Status • Status at Soudan: • mZIP detectors tested underground (2009), data analyzed, performance satisfactory • iZIP detectors: test run underground will start this falltests so far (above ground) indicate MUCH better discrimination • Next Dark Matter Run • Probably using both, mZIP and iZIP • Start with full pay load in summer 2011 • ~20 detectors, 10-15 kg Ge • Expected sensitivity: 5e-45 cm2(spin-independent WIMP-nucleon cross section) 15 kg @ Soudan
SuperCDMS at SNOLAB – W. Rau – SNOLAB workshop 2010 iZIP Technology +3 V 0 V Phonon sensors on top and bottom Basic configuration Electric fieldcalculation -3 V 0 V Mostly neutron background Ionization yield Surface events Recoil energy [keV]
SuperCDMS at SNOLAB – W. Rau – SNOLAB workshop 2010 SuperCDMS at SNOLAB • Scientific goal: sensitivity for WIMP-nucleon interaction cross section of 3e-46 cm2 • Target mass: ~100 kg of germanium • Total exposure: ~100 kg y • Detector type: 100 mm diameter iZIPs • Number of detectors: 75-100 • Start of construction possible in 2012 (subject to positive funding decision) • Start of operation in 2014
SuperCDMS at SNOLAB – W. Rau – SNOLAB workshop 2010 Detectors SuperCDMS@ SNOLAB : 100 mmh: 33 mm SuperCDMS@ Soudan : 3” h: 1” SuperCDMS @ SNOLABtowers First SuperCDMS100 mm Ge crystal CDMS tower CD-0 10/10 CD-1 10/11 CD-2/3 10/12 CD-4 10/12 Operation iZIP 100 mmionization test Design improvements Install towers New ReadoutDevelopment Detector Production Engineering Model
SuperCDMS at SNOLAB – W. Rau – SNOLAB workshop 2010 Cryogenics and Shield Layout • Cryogen free dilution refrigerator save on He cost and operations • Pb and inner poly within the OVC minimize contamination of shield / external gamma background • Thick copper cans provide clean shielding • Removable inner can mount detectors in ultra-clean room: minimize exposure to Rn / dust
SuperCDMS at SNOLAB – W. Rau – SNOLAB workshop 2010 Ladder Lab Tentative Layout SuperCDMS100 kg experiment COUPP 60 kg TF Utilities Utilities PICASSO
SuperCDMS at SNOLAB – W. Rau – SNOLAB workshop 2010 SuperCDMS Test Facility Motivation • Need to quantify strongly improved background discrimination • iZIPs seem to be good enough, BUT cannot be tested in above ground facility • Need underground facility with very good neutron shielding • Larger detectors have longer pulses • Interaction rate from environmental gammas increases with mass • Leads to pile-up, may not be able to operate detectors above ground at all • Need underground facility with good gamma shielding • May be able to use test facility at SNOLAB with variable shielding to study neutron environment (input for SuperCDMS shielding design or background Monte Carlo simulations)
SuperCDMS at SNOLAB – W. Rau – SNOLAB workshop 2010 SuperCDMS Test FacilityConcept Gas handling Cryostat Will be replaced by new remote controlled system He recovery LN Liquefier He Liquefier Cab New Cu Tails Super CDMS Underground Neutronfree Cryogenic Test Facility Magnetic Shielding Pumps Water Tank
SuperCDMS at SNOLAB – W. Rau – SNOLAB workshop 2010 SuperCDMS Test FacilitySystems / Tasks Management Tails Thermometry Automation Gas handling Liquefiers, impl. Magnetic shielding Shielding (tank) Drywell, deck Cold hardware Detector Wiring SUF cryogenic test FNAL system test SNOLAB work Berkeley FNAL Queen’s SLAC SNOLAB Stanford
SuperCDMS at SNOLAB – W. Rau – SNOLAB workshop 2010 SuperCDMS Test FacilitySchedule June 2011 September 2010 Start SUF work December 2010 Shipping to FNAL
SuperCDMS at SNOLAB – W. Rau – SNOLAB workshop 2010 Conclusions • SuperCDMS @ Soudan: • First engineering run completed • Second engineering run 2010/11 • Restart dark matter search in 2011 • iZIPs performance promising • SuperCDMS @ SNOLAB • Design is well underway • Entering DOE’s CD process hopefully later this year • Earliest possible start of construction: 2012 • Start of operation: 2014 • SuperCDMS Detector Test Facility at SNOLAB • Cryostat refurbishment underway • Most system components are at hand • Few open questions (magnetic shielding, detector wiring) • Commissioning at SNOLAB: mid 2011