More details can be found in Chapter 5 of the NA60+ Letter of Intent
Vertex spectrometer
The vertex spectrometer will be based on MAPS sensors presently under development for the ALICE ITS3 and NA60+ projects. Large area sensors will be built, thanks to the stitching technique. The present NA60+ set-up foresees from 5 up to 10 planes of MAPS, each built with 2×2 sensors (30×30 cm2)
Dipole magnet
The vertex spectrometer is immersed in the magnetic field generated by a dipole magnet. A viable candidate is the MEP48 magnet, presently stored at CERN. It has a 40 cm wide gap and can deliver up to 1.47 T
Muon spectrometer
The muon spectrometer is placed downstream of the vertex spectrometer, after a thick absorber that efficiently filters out the hadrons produced in the primary interaction. It includes six tracking stations. Groups of two stations are positioned upstream and downstream of the toroidal magnet, while the last two stations are placed downstream of a further hadron absorber, that helps in rejecting the remaining hadronic background. A modular design is foreseen, with the (approximately) circular symmetry realized with 12 modules for each station in the first group, 36 in the second and 84 in the third, for a total of 240 modules.
The MWPC and GEM technologies are presently considered for the realization of the muon spectrometer. A first prototype of a trapezoidal MWPC module was built and tested at Weizmann Institute in 2022.
Toroidal magnet
A working prototype of the toroidal magnet for the muon spectrometer was built at CERN in the frame of a collaboration between the CERN-DT, INFN Torino and INFN Cagliari groups, and was tested in 2021
Results of first preliminary tests can be found here
Hereafter some estimates of the properties of the full-scale magnet
