High efficiency gaseous tracking detector for cosmic muon radiography
  A tracking detector system has been constructed with an innovative approach to the classical multi-wire proportional chamber concept, using contemporary technologies. The detectors, covering an area of 0.58 square meters each, are optimized for the application of muon radiography. The main features are high (>99.5%) and uniform detection efficiency, 9 mm FWHM position resolution, filling gas consumption below 2 liters per hour for the non toxic, non flammable argon and carbon dioxide mixture. These parameters, along with the simplicity of the construction and the tolerance for mechanical effects, make the detectors to be a viable option for a large area muography observation system. 
Dezs\H{o} Varga, G\'abor Nyitrai, Gerg\H{o} Hamar, L\'aszl\'o Ol\'ah
physics.ins-det hep-ex