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CDMS/SuperCDMS

CDMS/SuperCDMS. Harry Nelson UCSB DUSEL Henderson at Stony Brook May 5, 2006. Background. Electron Recoils. E r. v/c  0.3. Sparse Energy Deposition. . WIMP Direct Detection. Signal. Nucleus Recoils. E r. v/c  10 -3. Dense Energy Deposition v/c small; <Bragg.

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CDMS/SuperCDMS

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  1. CDMS/SuperCDMS Harry Nelson UCSB DUSEL Henderson at Stony Brook May 5, 2006

  2. Background Electron Recoils Er v/c  0.3 Sparse Energy Deposition  WIMP Direct Detection Signal Nucleus Recoils Er v/c  10-3 Dense Energy Deposition v/c small; <Bragg Neutrons same, but 1020 higher – eliminate by going deep, shielding well 0 Density/Sparsity Basis of Discrimination Stonybrook DUSEL Workshop

  3. CDMS - 16 kg-d (at shallow site) DAMA - 58,000 kg-d ZEPLIN I - 230 kg-d Edelweiss - 12 kg-d Out of date (2002)… the impact of background 10-39 10-40 WIMP – nucleon  (cm2) 10-41 10-42 1000 10 104 1 100 Mass (GeV) Stonybrook DUSEL Workshop

  4. Sort of Deep Facility Soudan Mine Hosts: State of Minn., U Minn., Fermilab 690 meters underground 2090 meters water equivalent Stonybrook DUSEL Workshop

  5. Stonybrook DUSEL Workshop

  6. FET cards 4 K 0.6 K 0.06 K 0.04 K SQUID cards ZIP 1 (Ge) ZIP 2 (Ge) ZIP 3 (Ge) ZIP 4 (Si) ZIP 5 (Ge) ZIP 6 (Si) 14C 14C 14C A Cold Heart Results from first… poorer resolution Two `towers’ 6 detectors… 10 cm Tower 1: 4 Germanium (0.25 kg each), 2 Silicon (0.1 kg each) Stonybrook DUSEL Workshop

  7. Livetime (days) Towers 1 & 2 Tower 1 Livetime (days) Date Date First Year of Running CDMS II at Soudan • Mar.-Aug. 2004 “The Two Towers” • 74 livedays 1.5 kg of Ge, 0.6 kg of Si • More Barium Calibration • Oct. 2003- Jan. 2004 “Tower 1” • 53 livedays, 1 kg Ge, 0.2 kg Si Stonybrook DUSEL Workshop

  8. 0 Nuclear Recoil bad at making Ionization Holes e- Germanium more ionization! Need a second, `fair’ measure of deposited energy… sound!  Both deposit, say, 20 keV Stonybrook DUSEL Workshop

  9. Separation of the types of recoils Sound Stonybrook DUSEL Workshop

  10. Latest Search Plot… Small Circles: prior to surface rejection beta emitters Color: passing surface rejection Star: one candidate Stonybrook DUSEL Workshop

  11. Surface events from calibration source neutrons from calibration source Surface rejection • 2 based analysis significantly improves the surface event rejection • CDMS will not be background limited soon. Can indefinitely tighten cuts with increased exposure to maintain a discovery potential Stonybrook DUSEL Workshop

  12. Two Papers Just Published Stonybrook DUSEL Workshop

  13. Silicon: low mass New Limits (Spin Independent) 90% CL About twice more sensitive than 1-tower Stonybrook DUSEL Workshop

  14. ZEPLIN-1 Edelweiss PRELIMINARY CDMS- Soudan CDMS -projected The Near Future Installed 3 additional towers in November • Improvements • Cryogenics, backgrounds, DAQ • Currently commissioning • 30 detectors in 5 towers of 6 • 4.75 kg of Ge, 1.1 kg of Si to run through 2007 • Improve sensitivity x10 Stonybrook DUSEL Workshop

  15. SuperCDMS: Move south to balmy Sudbury Henderson Stonybrook DUSEL Workshop

  16. Stonybrook DUSEL Workshop

  17. Scale up: 25 kg, 150 kg stages 25 kg 2008 start Soudan 2010/11 SNOLAB 150 kg – beyond 2011 Stonybrook DUSEL Workshop

  18. Stonybrook DUSEL Workshop

  19. CDMS II ZIPs: 3” diameter x 1 cm = 0.25 kg Ge SuperCDMS ZIPs: 3” diameter x 1” = 0.64 kg Ge Detectors in `Super Towers’ • Thicker Detectors – less surface per volume • Revert electrode design – better rejection Stonybrook DUSEL Workshop

  20. Stonybrook DUSEL Workshop

  21. Elements leading to increased sensitivity • Thicker Detectors • Less surface/volume, factor of 2.5 • Better Analysis Rejection • Variety of improvements factor of 4 • Cleaner Detectors • Lead-210… (?) Radon Daughter, factor of 10 • Redesign detectors for better rejection • Factor of 10 • Factor of 1000, total… Stonybrook DUSEL Workshop

  22. Sensitivity Expectations: Distant Future Jun 07 2009 Stonybrook DUSEL Workshop

  23. Projected Sensitivies Stonybrook DUSEL Workshop

  24. Time Line Stonybrook DUSEL Workshop

  25. Infrastructure • Lower Campus (neutrons) • 20 m L  10 m W  10 m H (60  30  30 feet) • Liquid He and Nitrogen (compressor plant? 100 m2, 1000 sqft) … cryocooling reducing need… • 100 kVA electrical power • 200 m3/minute air flow (6000 cfm) • low Radon capability (details need work) • 5-ton crane Stonybrook DUSEL Workshop

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