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

 0 WIMP Direct Detection Signal Background Er Er Density/Sparsity Electron Recoils Background v/c  0.3 Sparse Energy Deposition Er 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 5/4/2006 Stonybrook DUSEL Workshop

Stonybrook DUSEL Workshop Out of date (2002)… the impact of background 10-39 10-40 CDMS - 16 kg-d (at shallow site) Edelweiss - 12 kg-d ZEPLIN I - 230 kg-d DAMA - 58,000 kg-d WIMP – nucleon  (cm2) 10-41 10-42 1 10 100 1000 104 Mass (GeV) 5/4/2006 Stonybrook DUSEL Workshop

Sort of Deep Facility Soudan Mine Hosts: State of Minn., U Minn., Fermilab 690 meters underground 2090 meters water equivalent 5/4/2006 Stonybrook DUSEL Workshop

Stonybrook DUSEL Workshop 5/4/2006 Stonybrook DUSEL Workshop

Stonybrook DUSEL Workshop A Cold Heart Results from first… ZIP 1 (Ge) ZIP 2 (Ge) ZIP 3 (Ge) ZIP 4 (Si) ZIP 5 (Ge) ZIP 6 (Si) 4 K 0.6 K 0.06 K 0.04 K SQUID cards FET cards 14C poorer resolution Two `towers’ 6 detectors… 10 cm Tower 1: 4 Germanium (0.25 kg each), 2 Silicon (0.1 kg each) 5/4/2006 Stonybrook DUSEL Workshop

First Year of Running CDMS II at Soudan Oct. 2003- Jan. 2004 “Tower 1” 53 livedays, 1 kg Ge, 0.2 kg Si Mar.-Aug. 2004 “The Two Towers” 74 livedays 1.5 kg of Ge, 0.6 kg of Si More Barium Calibration Date Towers 1 & 2 Tower 1 Livetime (days) 5/4/2006 Stonybrook DUSEL Workshop

Nuclear Recoil bad at making Ionization 0 Holes e- Germanium more ionization! Need a second, `fair’ measure of deposited energy… sound!  Both deposit, say, 20 keV 5/4/2006 Stonybrook DUSEL Workshop

Separation of the types of recoils Sound 5/4/2006 Stonybrook DUSEL Workshop

Stonybrook DUSEL Workshop Latest Search Plot… Small Circles: prior to surface rejection beta emitters Color: passing surface rejection Star: one candidate 5/4/2006 Stonybrook DUSEL Workshop

Stonybrook DUSEL Workshop 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 Surface events from calibration source neutrons from calibration source 5/4/2006 Stonybrook DUSEL Workshop

Two Papers Just Published 5/4/2006 Stonybrook DUSEL Workshop

New Limits (Spin Independent) Silicon: low mass 90% CL About twice more sensitive than 1-tower 5/4/2006 Stonybrook DUSEL Workshop

Stonybrook DUSEL Workshop The Near Future Installed 3 additional towers in November CDMS- Soudan CDMS -projected Edelweiss ZEPLIN-1 PRELIMINARY 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 Last fall we installed 18 additional detectors in 3 additional towers, for a total of 4 kilograms of germanium. Running these 5 towers of detectors for 9 months should improve our sensitivity by another order of magnitude. (0:15) 5/4/2006 Stonybrook DUSEL Workshop

SuperCDMS: Move south to balmy Sudbury Henderson 5/4/2006 Stonybrook DUSEL Workshop

Stonybrook DUSEL Workshop 5/4/2006 Stonybrook DUSEL Workshop

Stonybrook DUSEL Workshop Scale up: 25 kg, 150 kg stages 25 kg 2008 start Soudan 2010/11 SNOLAB 150 kg – beyond 2011 5/4/2006 Stonybrook DUSEL Workshop

Stonybrook DUSEL Workshop 5/4/2006 Stonybrook DUSEL Workshop

Detectors in `Super Towers’ CDMS II ZIPs: 3” diameter x 1 cm = 0.25 kg Ge SuperCDMS ZIPs: 3” diameter x 1” = 0.64 kg Ge Thicker Detectors – less surface per volume Revert electrode design – better rejection 5/4/2006 Stonybrook DUSEL Workshop

Stonybrook DUSEL Workshop 5/4/2006 Stonybrook DUSEL Workshop

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… 5/4/2006 Stonybrook DUSEL Workshop

Sensitivity Expectations: Distant Future Jun 07 2009 5/4/2006 Stonybrook DUSEL Workshop

Projected Sensitivies 5/4/2006 Stonybrook DUSEL Workshop

Stonybrook DUSEL Workshop Time Line 5/4/2006 Stonybrook DUSEL Workshop

Stonybrook DUSEL Workshop 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 5/4/2006 Stonybrook DUSEL Workshop