Transcript Document
Soudan Underground Laboratory
Features
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
HPGe Screening (SOLO)
Cu Electroform
New Clean Room
Fully lined with an
active muon veto
Gamma screening and isotope ID
High Purity Germanium
Diode-M 0.5kg in heavy use by XENON
managed 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
M. Laubenstein: in screening sites
around the world, the main
backgrounds are internal to the
detector and shielding itself
Copper Electroforming
(Reeves & Sons, LLC)
Funded via DOE Small Business Innovation Research grant
TASKS:
• Electroform and test a large vacuum copper cryostat
structural 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
Endcap mandrel (16" diam x 14”)
square cross arm mandrel
for cold finger + wires
A 2090 mwe experimental hall (35’x40’x100’)
lined with an active muon veto shield.
Ceiling veto panels
Veto tube
test stack
Refurbished Soudan2 Muon Veto shield
New 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
An interactive graphical interface program
retrieves the data remotely.
Currently studying muon angular distribution, multiplicity, shower fragments
Preliminary Angular
distribution from new
data
compared to
actual topological
map of overburden
S
W
N
E
S
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 ab 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
100 ft
n multiplicity
more muon tubes
Clean
room
Clean
room
Beta
Cage
mezzanine
Ge
Dark
Matter
Medtronics
Water tank
Muon veto shield
Muon veto shield
Muon veto shield
Active
Shielding
Active Muon Veto outside
tank
reduces for more
effective
depth
background from neutrons made
in the shield
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
Shielding
Active Muon Veto outside
tank
reduces for more
effective
depth
background from neutrons made
in the shield
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