Soudan Installation: Fermilab Constructing RF Clean Room HVAC & Radon Filtering Detector Preparation Room Electronics Hut Equipment Room CDMS II Overview - Gaitskell - CfPA EAB Review
CDMS II Overview - Gaitskell - CfPA EAB Review Soudan Mine First Iron Mine in Minnesota In production until 1962 => State Park & Site for Experimental Physics Existing Cavern 73x14x14 m3 Depth 713 m (2000 mwe) CDMS II Overview - Gaitskell - CfPA EAB Review
CDMS II Overview - Gaitskell - CfPA EAB Review Soudan Cavern New MINOS Cavern (not constructed yet) CDMS Huts, Fridge & Clean Rooms (Foundations going in) Existing Soudan I Experiment CDMS II Overview - Gaitskell - CfPA EAB Review
Soudan Gamma Background ~half that at SUF 20 cm Pb will achieve 0.03/keV/kg/day @10keV Rock Composition Ely greenstone 50% SiO2 15% Al2O3 ~20% CaO,FeO,MgO 5” Shotcrete on walls has ~2x activity Gammas/m2/s 2.8 MeV 1 104 CDMS II Overview - Gaitskell - CfPA EAB Review
Soudan Neutron Background /1 Low Energy (20 keV-5 MeV) Natural Radioactivity Dominant Source (a,n) a from U,Th on light nuclei =>2x10-8 n/g/s Fision => 2.7x10-9 n/g/s CDMS II Overview - Gaitskell - CfPA EAB Review
Soudan Neutron Background /2 High Energy (50 MeV-2 GeV) Muons In spite of low fluxes, “punch” through shield Significant in range 150 MeV->650 MeV Relative contribution of neutrons to detector hits MC of Neutron Spectrum from 5 m shell of rock due to hard muon spectrum CDMS II Overview - Gaitskell - CfPA EAB Review
Soudan Neutron Background /3 Shield Design Neutron Management Simple Shield 22 cm Pb inside 50 cm poly 10 poly; 8 Pb; 10 poly; 15 Pb; 30 poly (cm) CDMSII Target DM 0.0003 events/keV/kg/day CDMSII Target DM 0.0003 events/keV/kg/day Composite Shield Illustrated CDMS II Overview - Gaitskell - CfPA EAB Review
CDMS II Overview - Gaitskell - CfPA EAB Review Shield & Active Veto Cylindrical Geometry Plastic Scintillator Veto >99.8% Efficiency 12t Pb will generate neutrons which interact at 0.05 /keV/kg/day @ 10 keV Active Veto Poly & Pb ICEBOX FRIDGE CDMS II Overview - Gaitskell - CfPA EAB Review
Cryogenic Systems: Fermilab Purchased Dilution Refrigerator Fabricate CDMS II Icebox Design & Purchase Control Systems for Cryogenics Learning lessons from SUF operations CDMS II Overview - Gaitskell - CfPA EAB Review