Requirements:

  1. resolution <1% up to at least 1GeV.
  2. total length <800 mm
  3. limited encumbrance of the coil on the side of the fibers

To this aim both the magnetic field and the magnetic length are increased. A tentative map is shown mappa finale and it can be achieved with the requirements described in here

The rest of the detector is designed with the same logic as the v1 prototype, as shown here. The detector is 64 fibers longer than the v1 detector. The expected resolution at two possibile distances of the beam from the center of the magnet is shown here.