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Soudan Underground LaboratoryFeatures
Moderate depth (2100 mwe) augmented with active muon veto shield
Existing infrastructure (power, water, networking, personnel, cranes, etc) and running experiments
ESO and EPS in place External Sales Org = non-overheaded user invoicing
mine labor, supplies, cryogens… Experimental Planning Statement = new experiments or screeners can be approved quickly (safety, materials, scheduling)
Radon levels change seasonally: 300 – 700 Bq/m3
Space for expansion, including enough for a 10 m dia x 6 m high water tank
Mature Education and Outreach program with visitor’s center and tours
Soudan Underground Laboratory
CDMS office
New Clean Room
CDMS Exp.
MINOS
Fully lined with an active muon veto
Shielded hall
Cu Electroform
HPGe Screening (SOLO)
Diode-M 0.5kg in heavy use by XENONmanaged by Brown U (Gaitskell)
http://particleastro.brown.edu/SOLO
Gator 1.2 kg Florida Start-up moved (Mar 2007) to Gran Sasso
Gopher 1.2 kg Coming in January CDMS has many samples
Gamma screening and isotope ID
High Purity Germanium
M. Laubenstein: in screening sites around the world, the main backgrounds are internal to the detector and shielding itself
TASKS:
• Electroform and test a large vacuum copper cryostatstructural integrity up to 2 atm, cooling capabilities, and electronic noise.
• Measure the amount of thorium-232 in the electroformed copper. PNNL measured < 1uBq/kg of 232Th in the copper
• New Screener R&D to measure large quantities of Cu down to 0.1 uBq/kg
square cross arm mandrel for cold finger + wires Endcap mandrel (16" diam x 14”)
Funded via DOE Small Business Innovation Research grant
Copper Electroforming (Reeves & Sons, LLC)
A 2090 mwe experimental hall (35’x40’x100’) lined with an active muon veto shield.
Refurbished Soudan2 Muon Veto shieldNew gas system and controllers
Pump jacks for tube repair
New DAQ: Database of muons available to users: time stamp and location
On Mezzanine:New Clean room Additional coincident tubes
Structural support for lead cages
Veto tube test stack
Ceiling veto panels
An interactive graphical interface program retrieves the data remotely.
Preliminary Angular distribution from new data
compared to
actual topological map of overburden
S W N E S
Currently studying muon angular distribution, multiplicity, shower fragments
What moves into this space?
Medtronics soft memory error study is already there
Dark Matter Ge Detector (December 2007)
Neutron Multiplicity Counter: DUSEL R&D project (Case and UC Santa Barbara)
Ultra-sensitive Screeners: Beta cage, XIA counter, and Reeves Cu screener
Still room for a large multi-purpose water tank Good match for the space and good usage of a pre-existing muon shield
Muon veto shield
Mu
on v
eto
shie
ldM
uon
veto shield
100 ft
mezzanine
Clean room Beta
Cage
more muon tubes Clean room
Water tankGe Dark Matter
Medtronics
n multiplicity
Active Shielding for more effective depth
99.5% Muon Veto reduces n’s from shield by x 200
and n’s produced in rock by 4
Total n bkgd
~ 8 x 10-6 n/day/kg
Active Muon Veto outside tank reduces background from neutrons made in the shield
Active Shielding for more effective depth
For Homestake depth, both curves drop by 30-40
Without an active veto, 4850 mwe is 4 times worse than 2100 mwe
Total n bkgd
Active Muon Veto outside tank reduces background from neutrons made in the shield