A Borehole Muon Telescope for Underground Muography

Radiographic imaging with muons by absorption, also called Muon Radiography or Muography, is a methodology based on the characteristic of the matter to be crossed by high energy muons. This physical property allows muons to pass through the material with a measurable degree of absorption depending on the density of the material. Muon Radiography applies to several different situations and is particularly suitable for investigating subsoil of civil or archaeological interest. This kind of applications needs the muon detector to be installed below the target region. A novel borehole cylindrical detector has been built and tested for use in harsh conditions and for limited space installations. It is based on the past expertise with scintillator detectors and is composed of two types of scintillating elements, bar-shaped and arcshaped. Due to its size, it can be easily installed in drilled holes of 25 cm in diameter or more, typically economical to make. Here, we describe the idea, commissioning, and some preliminary results.