Technical characterization of Calliolab, the new underground laboratory for physics research in Pyhäsalmi mine

The development of the infrastructure for scientific work in the Pyhäsalmi mine is currently administered under the Calliolab project, which is managed by a consortium of the Universities of Oulu and Jyväskylä and regional organizations. A new laboratory has been developed in one of the tunnels at 1430 m depth in Pyhäsalmi mine. At this depth the cosmic-ray muon flux is attenuated down to one ppm compared to that on the surface, making the new laboratory an excellent location to conduct astro-particle physics research and material testing, which require ultra-low cosmic-ray background environment.