Ionization cluster detection by means of an electroluminescent drift chamber

Possibility of detecting ionization clusters by means of standard wire drift chamber with the light read-out is investigated. The light was collected by light pipe containing re-emittor, via controlled by two photomultipliers switched in coincidence. In detecting clusters the chamber was pumped with Ar+15% CH4 gas mixture and operated in proportional mode. Single electron signal duration was 5-7 ns. The mean density of β-particle detected clusters is 12 and 9.5 cm-1, the drift field being respectively 40 and 100 V/cm in transverse drift geometry and discretization time of 2 ns