Particle accelerator that produces charged particles having variable energies

A synchrocyclotron comprising:

• a voltage source to provide a radio frequency (RF) voltage to a cavity to accelerate particles from a particle source,
• a coil to receive electrical current having one of multiple values and to generate a magnetic field corresponding to the electrical current, the magnetic field for causing the particles to move orbitally within the cavity at an energy that corresponds to the electrical current, the magnetic field being at least 4 Tesla;
• at least one magnetic pole piece, the at least one magnetic pole piece comprising ferromagnetic material and being controllable to adjust the magnetic field corresponding to the electrical current;
• and
• an extraction channel to receive the accelerated particles and to output the received particles from the cavity, the particles that are output from the cavity having an energy that corresponds to the electrical current;
• wherein the synchrocyclotron is configured to enable setting of the electrical current to different ones of the multiple values to cause particles output from the cavity to have different energies corresponding to the different ones of the multiple values;
• and
• wherein the energy of the particles that are output from the cavity are variable in a range that is between about 100 MeV and about 300 MeV.