Muography and the Paarl African Underground Laboratory

International audience ; Shielding from cosmic background is an essential element in rare event searches.One of the ways to do this is to conduct experiments in underground laboratories which provide shielding by hundreds of meters of rock. To this end, there has been a commitment to develop such laboratory in South Africa called the Paarl African Underground Laboratory (PAUL). Muons, which are secondary particles stemming from cosmic rays, are able to penetrate several kilometres of rock due to their highly energetic nature. Muon imaging or muography is one of the powerful and complementary methods that can help unravel the internal secrets of natural edifices. As part of a broader plan to measure the muon flux at the overburden in the Huguenot Tunnel, open sky measurements were undertaken using a muon telescope. These measurements were done at Stellenbosch University and at the University of the Western Cape and they form part of the calibration process. The muon telescope is currently stationed inside the tunnel with an endeavour to find the muon flux rate therein and help map the topography of the overburden. This information will be used to decide the location of PAUL inside the tunnel.