Faster ramp of LHC for use as an FCC High Energy hadron Booster

This note examines the feasibility of ramping the LHC magnets faster than the present operation, in view of a reuse of LHC as a High Energy hadron Booster. Such a synchrotron would inject 3.3 TeV beams into a larger Future Circular Collider. The main constraints are examined. The conclusion is that the ramp up could be shortened by a factor of 4, with the main dipoles ramping up at 50 A/s instead of 10 A/s and a modified formulation of the ramp function. On the hardware side this would require a voltage upgrade of the dipole power converters and a possible further splitting of the dipole circuits in halves. To make similar gains for the ramp down time, modifications to some of the one-quadrant power converters, would also be needed, including the main quadrupoles.