MDC reference systems relevant for Simulation, Digitisation and Analysis

Objects are viewed from the target position. Front side refers to the side facing the target.

Front view: the blue lines indicate the outer shape of the chamber

Side view: the red lines indicate the position of the 7 cathode planes, the blue lines are the 6 sense planes

1. Module Reference System (x')

The origin of the reference system is attached to the physical center point of the drift chamber module, i.e. the intersection of a normal onto the fourth cathode plane originating from the target point.



2. Layer Reference System (x'')

This reference system emerges from the module reference system by a shift along the z-direction such that z''=0 falls onto the respective sense layer. Further by a rotation around the z'' axis such that x'' is parallel to the theoretical position of the wires of the respective layer.



3. Cell Reference System (x''')

This is a one-dimensional reference system which gives the distance of a hit to the actual position of the respective wire.