A new type accelerator is being developed for the next generation particle therapy system. This accelerator utilizes a weak focusing DC magnetic field and a frequency modulated RF acceleration. Since a superconducting magnet is applicable to the main magnet, the accelerator can be compact. The accelerator characteristically has cotangential orbits to form an orbit-concentrated region. A beam is extracted from the region by using a new extraction method with the trans-verse RF kicker, peeler and

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... regenerator magnetic fields. In this method an extracted beam energy can be controlled by applied time of the acceleration RF voltage without using an energy selection system (ESS). Intensity and pulse width of the extracted beam can be controlled by a voltage and / or a frequency pattern of the RF kicker.