Conditions of environment

Table 1. Experimental parameters and infrastructure of the site
Depth (max.) 4,000 meters of water equivalent (m.w.e.)
Composition of the rock
Average density 2.8 g·cm–3
Rock temperature at 4000 m.w.e. 22 oC
Muon flux 1,1×10–4 m–2·s–1
Radon concentration 20 Bq·m–3 in ventilated areas
Neutron flux a few x 10–6 cm–2·s–1 (depending on energy)
Infrastructure 3 MW independent electric power supply
Air conditioning and thermalization
Air extraction and forced ventilation in/from outside
Optical GBLAN, 100 to 1000 MB connection to outside
Two-way radio network both on the surface and underground for safety


Measured muon flux at different depths in the Pyhäsalmi Mine (blue symbols) compared with WIPP (red triangle), Boulby (red circle) and LNGS (red square).