Underground multi-muon experiment EMMA P. Kuusiniemi1, L. Bezrukov2, T. Enqvist1, H. Fynbo3, L. Inzhechik2, P. Jones4, J. Joutsenvaara1, T. Kalliokoski4, J. Karjalainen1, K. Loo1,4, B. Lubsandorzhiev2, T. Monto4, V. Petkov2, T. Räihä1, J. Sarkamo1, M. Slupecki4, W.H. Trzaska4, and A. Virkajärvi4 1Oulu Southern Institute and Department of Physics, University of Oulu, Finland 2Institute of Nuclear Research, Russian Academy of Sciences, Moscow, Russia 3Department of Physics and Astronomy, University of Aarhus, Denmark 4Department of Physics, University of Jyväskylä, Finland
Received: 12 Nov 2010 – Revised: 10 Jan 2011 – Accepted: 10 Jan 2011 – Published: 12 Apr 2011
Abstract. EMMA is a new experiment designed for cosmic-ray composition studies around the knee energy operating at the shallow depth underground in the Pyhäsalmi mine, Finland. The array has sufficient coverage and resolution to determine the multiplicity, the lateral density distribution and the arrival direction of high-energy muons on an event by event basis. Preliminary results on the muon multiplicity extracted using one detector station of the array are presented.