A detailed comparison of the PG and IHEP designs:
- Supporting structures
- Beams and cross
- Readout placement
- Airex structures between silicon layers
- Definition of the area where silicon sensors can be installed
EM presented a comparison between PG and IHEP SCD mechanical designs. Discussion followed on several point:
- Supporting structures: IHEP design includes beams in side and top detector in the middle of acceptance. PG will do some simulation to see if it is possible to remove those bars (alt least for the side-SCD), compensating the stiffness with thicker SCD supporting layers. Results of this analysis are foreseen for later on this month.
- Location of the electronics: in order to enlarge the side-SCD active area PG proposes to have all electronics read-out on the bottom. This implies some different routing of the strips for the orthogonal plane, à là AMS. This will result in longer strips and a double number of bondings. Another possible routing with standard ladders and electronics on the bottom with a complicated routing have been discussed. PG will think about this. While the tracking would be affected by the routing à là AMS since it has to solve the multiplicity of signals (using independent detectors?), the impact on charge should be under control.
- Remark from Giovanni: we should do the effort of maximizing the active area and try to cover the corners of the instrument.
- Airex support: in PG design the first silicon plane is glued to the supporting plane. On top of it an airex support is attached and the second silicon layer is glued on top of it. In IHEP design the two planes are glued together.
