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