Improving the performance of the liquid argon TPC by doping with tetra-methyl-germanium

Abstract In order to recover the charge lost by electron-ion recombination, we doped pure liquid argon with a photosensitive hydrocarbon, tetra-methyl-germanium (TMG), in the 3 ton ICARUS TPC. A charge increase of 25% to 220% was observed for different electric fields and for energy densities ranging from 1.6 to 32 MeV/cm.