SuperCDMS at SNOLAB Wolfgang Rau, Queen’s University for the SuperCDMS Collaboration

CDMS / SuperCDMS Timeline SuperCDMS at SNOLAB – W. Rau – SNOLAB workshop 2010 CDMS / SuperCDMS Timeline 1998 - 2002 CDMS I 6 detectors 1 kg Ge (30 kgd )  < 3.5e-42 cm2 2003 - 2013 CDMS II (until 2009) 30 detectors ~4 kg Ge (300 kgd)  < 3.5e-44 cm2 SUF, 10 mwe SuperCDMS @ Soudan ~20 detectors 10-15 kg Ge (~1200 kgd)  < 9e-45 cm2 Soudan, 2100 mwe exposures are after all cuts! 2011 - 2017 SuperCDMS @ SNOLAB 80-90 detectors 100 kg Ge (~35000 kgd)  < 3e-46 cm2 SNOLAB, 6000 mwe SuperCDMS test facility @ SNOLAB (2011)

SuperCDMS Collaboration SuperCDMS at SNOLAB – W. Rau – SNOLAB workshop 2010 SuperCDMS Collaboration California Institute of Technology Z. Ahmed, J. Filippini, S.R. Golwala, D. Moore Fermi National Accelerator Laboratory D. A. Bauer, F. DeJongh, J. Hall, D. Holmgren, L. Hsu, E. Ramberg, R.L. Schmitt, J. Yoo Massachusetts Institute of Technology E. Figueroa-Feliciano, S. Hertel, S.W. Leman, K.A. McCarthy, P. Wikus NIST * K. Irwin Queen’s University C. Crewdson *, P. Di Stefano *, J. Fox *, S. Liu *, C. Martinez *, P. Nadeau *, W. Rau Santa Clara University B. 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 University J. Cooley Stanford University P.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 University M. Kos, M. Kiveni, R. W. Schnee Texas A&M K. Koch*, R. Mahapatra, M. Platt *, K. Prasad*, J. Snader University of California, Berkeley M. Daal, T. Doughty* , N. Mirabolfathi, A. Phipps, B. Sadoulet, D. Seitz, B. Serfass, D. Speller*, K.M. Sundqvist University of California, Santa Barbara R. Bunker, D.O. Caldwell, H. Nelson University of Colorado Denver B.A. Hines, M.E. Huber University of Florida T. Saab, D. Balakishiyeva, B. Welliver * University of Minnesota H. 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 Zurich S. Arrenberg, T. Bruch, L. Baudis, M. Tarka * new collaborators or new institutions in SuperCDMS

Overview CDMS Technology SuperCDMS at Soudan iZIP Detectors 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

Ionization energy [keV eeq] SuperCDMS at SNOLAB – W. Rau – SNOLAB workshop 2010 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 Thermal coupling Thermal bath Phonon sensor + - Target e n Ionization energy [keV eeq] Phonon signal Electron recoils from β’s and γ’s Electron recoil Nuclear recoil Charge signal Nuclear recoils from neutrons Phonon energy [keV]

SuperCDMS at Soudan Detectors New detectors: 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 Soudan Status Status at Soudan: 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 fall tests 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

iZIP Technology Basic configuration Phonon sensors on top and bottom SuperCDMS at SNOLAB – W. Rau – SNOLAB workshop 2010 iZIP Technology Basic configuration +3 V 0 V -3 V Phonon sensors on top and bottom Electric field calculation Mostly neutron background Ionization yield Surface events Recoil energy [keV]

SuperCDMS at SNOLAB – W. Rau – SNOLAB workshop 2010 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 Milestone (DOE) FY2010 FY2011 FY2012 FY2013 FY2014 CD-0 mission need 10/1/10 CD-1 prelim. design, cost range 10/1/11 CD-2 baseline design and cost 10/1/12 CD-3 start of construction CD-4 start of operations 10/1/14

Detectors First SuperCDMS 100 mm Ge crystal CDMS tower SuperCDMS at SNOLAB – W. Rau – SNOLAB workshop 2010 CDMS tower SuperCDMS @ SNOLAB towers Detectors SuperCDMS @ SNOLAB : 100 mm h: 33 mm SuperCDMS @ Soudan : 3” h: 1” First SuperCDMS 100 mm Ge crystal CD-0 10/10 CD-1 10/11 CD-2/3 10/12 CD-4 iZIP 100 mm ionization test New Readout Development Engineering Model Operation Install towers Detector Production Design improvements

Cryogenics and Shield Layout 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

Ladder Lab Tentative Layout SuperCDMS 100 kg experiment COUPP 60 kg TF SuperCDMS at SNOLAB – W. Rau – SNOLAB workshop 2010 Ladder Lab Tentative Layout SuperCDMS 100 kg experiment PICASSO COUPP 60 kg TF Utilities

SuperCDMS Test Facility 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 Test Facility Concept SuperCDMS at SNOLAB – W. Rau – SNOLAB workshop 2010 SuperCDMS Test Facility Concept Cryostat Gas handling Will be replaced by new remote controlled system He recovery LN Liquefier He Liquefier New Cu Tails Cab S uper C DMS U nderground N eutronfree C ryogenic T est F acility Pumps Magnetic Shielding Water Tank

SuperCDMS Test Facility Systems / Tasks SuperCDMS at SNOLAB – W. Rau – SNOLAB workshop 2010 SuperCDMS Test Facility Systems / 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 X (X)

SuperCDMS Test Facility Schedule SuperCDMS at SNOLAB – W. Rau – SNOLAB workshop 2010 SuperCDMS Test Facility Schedule September 2010 Start SUF work June 2011 December 2010 Shipping to FNAL

Conclusions SuperCDMS @ Soudan: First engineering run completed 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