Pattern-recognition and Reconstruction for Muon Tracking

This note examines pattern-recognition and track reconstruction issues for the scintillator tracking system of the UT Maya Muon detector [1]. The basic geometry and performance characteristics of the tracking system are described in [2]. As described in the references, the scintillator strips are assumed to form helices of a fixed pitch-angle θs on their respective tracking layers. The tracking layers are right-circular cylinders with approximately the same radius R (differing by the thickness of the scintillator strips and adhesive) and are taken to have the same length L projected along the common axis of the three layers. The detector was designed with the inner layer having a helical pitch of -30 degrees, the middle layer with zero pitch and the outer layer with a pitch of +30 degrees. The detector, as built, has slightly different helical pitch angles on the inner and outer layers. Because of this and the differing radii of the tracking layers, it becomes easier to describe the geometry of the stereo strips by an overall “wrap angle” Ωs = tan θs L/R, which represents the change in azimuth of a strip as one goes from the bottom of the detector to the top. In this representation, the equation describing the helix associated with each scintillator strip has the form: