Energy selection system for compact proton therapy

An achromatic superconducting magnet assembly to selectively bend a proton beam away from a proton accelerator toward first and second treatment rooms, comprising:

• an outer vacuum chamber configured with a proton beam entry point, a first beam path leading to a first proton beam exit point, and a second beam path leading to a second proton beam exit point pointing in a direction different from the first proton beam exit point;
• and
• a bidirectional superconducting magnet unit configured proximate the proton beam entry point to selectively bend the proton beam to the first or second beam path;
• wherein each of the first and second beam paths comprise:
• a first combination of superconducting dipole and quadrupole magnets configured to receive the proton beam from bidirectional the superconducting magnet unit,
• a second combination of superconducting dipole and quadrupole magnets configured to transmit the proton beam out of the achromatic superconducting magnet assembly, and
• a collimator configured between the first and second combinations of superconducting dipole and quadruple magnets and configured to select the proton beam with desired energy levels.