Typical Histograms

Typical plots for DC planes are presented in Figure 1 (upstream), and Figure 2   (downstream). In the upstream DC plane more than 50% of the hit wires have a multiplicity of one. When moving downstream the number of wires with a multiplicity of two rises. Upstream, the detector is dominated by highly ionizing muon tracks and the ionization density results in a single hit per track. This would not occur downstream where the majority of particles are poorly ionizing positrons, and a single track may produce multiple hits. In a typical PC plane (see Figure 3 ) the number of wires with multiple hits is much less than in the DC planes. Signals caused by a passing particle travel much faster in the PC chamber gas. In the event of multiple PC signals all may arrive at the sense wire within a very short time window and count as only one hit.