  SPPC (Super Proton-Proton Collider) is a discovery machine that is designed
for energy frontier research in two decades from now, as the second stage of
the CEPC-SPPC project. The main objective is to carry out experiments at 125
TeV in center-of-mass energy in a two-ring collider of 100 km in circumference
and 20 T in dipole field. This white paper about SPPC describes the machine
related issues, including performance, design overview, design challenges, key
technologies and their maturity and required R&D, staged options and upgrades,
synergies with other facilities, and environmental impacts.
