SNOLAB Underground Facilities

SNOLAB _underground_900.jpg

Photo by Gerry Kingsley

The SNOLAB underground laboratory is an expansion of the original SNO facility consisting of a large cavern housing the detector and ancillary spaces in mining drifts for the experiment and personnel infrastructure. The main level of the laboratory is located at the 6800 ft level of the mine with 2070 m of granitic rock overburden. The ambient rock temperature at this depth is 42C. Surface elevation at the site is 309 m above sea level. The surface topology is approximately flat. Access to the 6800 Level and SNOLAB is via 9 Shaft, located 1.8 km from the laboratory entrance. SNOLAB was designed to operate as one large clean room, in keeping with the successful approach used by SNO. Personnel entering the laboratory pass through showers and change into clean room clothing. Equipment entering the laboratory is either cleaned in a carwash before entering the lab or shipped underground in sealed clean containers that are opened after being washed and brought into the lab. 

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The SNOLAB expansion added an additional 6,300 m2 of excavations of which 3,700 m2 is clean room space attached to the existing facility. The clean/dirty boundary was moved for the expanded laboratory and some existing excavations were converted to additional clean space. The SNOLAB underground laboratory has 5,000 m2 of clean space. Of this, 3,100 m2 is experimental laboratory space. There is an additional 2,600 m2 of excavation outside the clean room used by SNOLAB for the service infrastructure and material transportation and storage. The clean spaces of the laboratory have shotcreted and painted walls, and painted concrete floors. Outside the lab most areas are bolted and screened but not shotcreted or painted. The material handling area immediately outside the laboratory entrance has concrete pads, and other areas have bare gravel on the drift floors. 

SNOLAB construction took place in two phases. Phase I added a new laboratory entrance and service facilities (chiller, generator, waste water treatment), and new experimental areas: a network of drifts (Ladder Labs) for small and medium sized experiments and a large experimental hall (the Cube Hall) for a bigger experiment. Phase II consisted of an additional lager experimental space dubbed the Cryopit. The Cryopit is designed for an experiment using a large volume of cryogenic liquid and is isolated from the rest of the laboratory for safety in the event of a cryogen leak. In addition to the new laboratory space, there is also the existing SNO cavern and its associated Utility Drift and control room. As well, the relocation of the personnel facilities made the existing South Drift available for experiments or laboratory infrastructure. SNOLAB’s experimental spaces are listed below.

Laboratory Space Style Length (ft) Width (ft) Height Area

SNO+ Cavern (Existing)

Cavern

Utility Drift

Control Room

72

187

57

 

23

20

85

 

 

3848

4300

1140

South Drift (Existing)

Drift

106

17

10/17

1802

Ladder Labs (Phase I)

Drift C1

Drift C2

Drift B&D

105

75

360

20

25

15

12/19

17/25

10/15

2100

1875

5400

Cube Hall (Phase I)

Hall

Utility Drift

Staging Area

Control Room

60

115

45

62

50

20

16

18

50/65

10/17

10/15

10/16

3000

2300

720

992

Cryopit (Phase II)

Cavern

Utility Drift

Staging Area

Control Room

50

141

66

64

 

20

16

16

50/65

10/15

10/15

10/15

1963

2820

1056

1024

Existing Phase I

Phase II

 

 

 

 

11090

27477

34340

Entrance and Personnel Facilities

photo-lunch-room-110302-03.jpgThe laboratory entrance is the transition from the dirty mine environment to the CLASS 2000 clean room interior of the laboratory. Initially adjacent to the SNO facilities, it was relocated to encompass the new experimental facilities. Its capacity was increased by a factor of two to accommodate the new lab’s larger work force. Material entering the laboratory transitions through a carwash where it is cleaned. Personnel entering the laboratory must shower and change into clean room clothing. In addition to showers and change rooms, the personnel facility has a lunchroom, meeting rooms and laundry facilities. The personnel drift also serves as SNOLAB’s refuge station in the event of an emergency in the mine. The personnel facilities are equipped to host 50 people underground during a shift.