Improved particle identification using cluster counting in a full-length drift chamber prototype

Single-cell prototype drift chambers were built at TRIUMF and tested with a ~ 210 MeV / c beam of positrons, muons, and pions. A cluster-counting technique is implemented which improves the ability to distinguish muons and pions when combined with a traditional truncated-mean charge measurement. Several cluster-counting algorithms and equipment variations are tested, all showing significant improvement when combined with the traditional method. The results show that cluster counting is a feasible option for any particle physics experiment using drift chambers for particle identification. The technique does not require electronics with an overly high sampling rate. Optimal results are found with a signal smoothing time of ~ 5 ns corresponding to a ~ 100 MHz Nyquist frequency.