Decisions about beam characterization and spreaders
After BC1:
* longitudinal measurement
* emittance measurement
After BC2:
* longitudinal measurement
* emittance measurement
* they both before the low-energy spreader
After Linac 3:
* nothing
Before undulators
* emittance measurement
After undulators:
* TDC + Dipole : two options one station per line or, if significantly cheaper, 1 TDC in a single dump for both beams
* In the preferred case of two TDC one per beam, we could use a single klystron serving both structures.
