The numbers given below include both arms. Table 1 gives the list for the default version of the spectrometer. In terms of production is has two defects:

• Frame 4 contains 1 module with a single sensor (Module 3). This means we need to design, produce and test a specific M-substrate for only 2 modules.
• Frame 5 contains 2 modules (module 8) where sensor types are mixed within one module (type 3 and 4). Furthermore one M-substrate on this modules is only partially equipped with D-substrates.

We discussed various possibilities to overcome these problems. The proposed version simplifies the production by reducing the number of different module and M-substrates

• Frame 4: The single-sensor module and one module 2 are replaced by two new modules, which are identical to Module 7 but have type 2 sensors instead of type 3. This removes the single-sensor M-substrate.
• Frame 5: Module 8 can be simplified by using type 3 wafers in place of the two type 4 wafers. The resulting module is identical to Module 6, thus removes one type of module and all partially equipped M-substrates.

The simplification comes on the expenses of 50 additional substrates. It increases the granularity in frame 5 near the beam pipe and the acceptance in frame 4. Consequently frame 4 needs to be longer in the proposed version.