Performance of 2 mm radius straw tube drift cells

Test beam data and cosmic ray data have been collected with a straw tube drift chamber. A resolution of 135 μm was achieved using TDC readout and 50% ethane, 50% Ar gas. Hit finding and track finding efficiencies for single tracks exceed 95%. Resolutions using TDC and FADC readouts simultaneously were compared. It is found that, for low gas gains, the FADC readout, results in a lower resolution than when TDC readout is used. For larger gas gain, the TDC resolution improves, exceeding the performance with FADC readout. Adequate resolution is achieved using either the TDC readout or the FADC readout at moderate gas gain