SiD ECal Geometry

In the validated SiD design, the electromagnetic calorimeter (ECal) barrel sits between the silicon tracker and the hadron calorimeter (HCal), at an inner radius of 1264 mm from the interaction point with a z extent of 3.53 m. It is made of twelve trapezoidal modules that extend the full z length of the detector. These modules have a small inner angle of 30^o and overlapping ends to avoid projective cracks through the detector. This creates an asymmetric structure that is periodic in increments of π/6 radians. The effect of this structure on potential physics measurements is considered.