Jan. 13,2003

Bill Miller, U of M

Off-Axis Detector

• Quick Overview of Potential Detector Hall

• Gas Handling

• Some Soudan numbers

• ODH

• Flammable Gas

Jan. 13,2003

Bill Miller, U of M

Possible Detector Hall

• Large 30 ft overburden makes it cost effective to put hall underground and use stable rock for sidewalls.

• Does raise some materials handling issues.

• More details on Detector Hall costs at meeting next week.

Jan. 13,2003

Bill Miller, U of M

Detector Hall Dimensions

• Detector Area– 100m long x 20m wide x 20m tall

• Detector hall – This includes lifting bays, storage, office areas, egress

walkways, access levels, stairs, elevators and mechanical area.

– 148m long x 28m wide x 29m tall

• Long 120m loading dock ramp to get loading bay under crane

Jan. 13,2003

Bill Miller, U of M

Cross Section Off-Axis Hall

Jan. 13,2003

Bill Miller, U of M

Side view of Detector Hall

Jan. 13,2003

Bill Miller, U of M

Floor Plan-Detector Area

Jan. 13,2003

Bill Miller, U of M

Floor Plan-Loading Bay

Jan. 13,2003

Bill Miller, U of M

Gas Handling

• Since the detector is note very far underground it is feasible to pipe from surface building.

• This makes gas delivery simple

• It is assumed that a gas mixing system would be used for the large volumes needed.

Jan. 13,2003

Bill Miller, U of M

Soudan 2 Main Detector• Argonne/15% CO2 gas mixed underground using dewers

of Argonne and K bottles of CO2. We used on average about 200 cubic feet per day.

• The gas system tracked with the barometer keeping 2” water overpressure. We used a gas re-circulation system with DeOxo’s to remove oxygen.

• The detector had enough leaks the gas system did not exhaust except for very severe storms.

• We had 3600 m of gasket sealed cracks, 3600 m of 1” nylon return hose, 4500 m of 3/8” nylon supply hose, 1800 sweglock fitting, 4 gas pumps with DeOxo's and charcoal filters. Total gas volume about 9600 cubic ft.

Jan. 13,2003

Bill Miller, U of M

Soudan 2 Veto Shield

• The Veto Shield consisted of roughly 1700 modules. Average size was 7 m long x 10 cm x 20 cm. Total gas volume is about 8600 cubic ft.

• The Veto shield used a similar re-circulation system with a DeOxo to remove O2.

• The Shield had 13,600 epoxied wire connections, 6800 connections and thousands of feet of 3/8” nylon hose.

• Total leak rate was about 50 cubic ft/day

Jan. 13,2003

Bill Miller, U of M

Total Soudan Gas Usage

• Approximately 18,220 cubic ft of gas volume (600 cubic meters)

• Total leak rate/top-up rate of about 250 ft/day (8.5 cubic meters)

• Volume of cavern 550,00 cubic ft (19,000 cubic meters)

• NO ODH problems

Jan. 13,2003

Bill Miller, U of M

ODH in Off-Axis Hall• Detector Volume comparison:

– Soudan=600 cubic meters– Off-Axis=2400 cubic meters

• Detector Hall comparison– Soudan=19,000 cubic meters– Off-Axis=120,000 cubic meters

• Wild guess of leak rate :– Soudan rate 8.5 cu. m/day – Off-Axis (4x Soudan)=34 cu m/day

• Should still be OK for Oxygen levels

Jan. 13,2003

Bill Miller, U of M

Flammable Gas Problems

• Gas detection devices needed

• Proper collection of leaked gas and venting out of cavern

• Emergency venting for power outages

• Mix gas in separate building on surface and pipe underground