Method of manufacturing radio frequency accelerator, radio frequency accelerator, and circular accelerator system

A radio frequency accelerator comprising:

• a first-stage linear accelerator for accelerating charged particles injected into the first-stage linear accelerator from an ion source to extract the accelerated charged particles as a charged particle beam;
• a second-stage linear accelerator for accelerating the charged particle beam injected into the second-stage linear accelerator from the first-stage linear accelerator through a matching section to extract the accelerated charged particle beam;
• a radio frequency power source for generating total radio frequency power to be supplied to the first-stage linear accelerator and the second-stage linear accelerator;
• and
• a power distributor for distributively supplying the total radio frequency power supplied from the radio frequency power source to the first-stage linear accelerator and the second-stage linear accelerator, wherein
• a value of a power distribution factor R for the power distributor to supply the radio frequency power to the second-stage linear accelerator and a value of a ratio L/ω of a length L of the matching section between an outlet of the first-stage linear accelerator and an inlet of the second-stage linear accelerator to an angular frequency ω of the radio frequency power are set so that the charged particle beam is extracted from the second-stage linear accelerator over a range of the total radio frequency power wider than a widest allowable range among allowable total radio frequency power ranges determined for each phase of charged particles on the basis of phase acceptance of the second-stage accelerator.