| From 1990s, Fixed Field Alternate Gradient (FFAG) accelerator has been significantly developed for its advantages of a larger dynamic aperture and a higher output beam power comparing with conventional synchrotrons or cyclotrons. This type of accelerator can be used as the driver of the Accelerator Driven System (ADS) and the Spallation Neutron Source (SNS), the collider of the neutrino factory, or be used in the tumor treatment, etc. A small He ion FFAG accelerator has been designed at National Synchrotron Radiation Laboratory in University of Science and Technology of China to study the generating mechanism of Helium (He) in the iron caused by the neutron radiation and the corresponding embitterment problem induced by He, with highest He ion energy of 36 MeV. One superperiod of this accelerator is composed of three combined function bending magnets, with a defocusing, focusing and defocusing sequence. The revolutionary period of the He ion in this accelerator varies from hundreds of ns to several us. By considering the low beam energy and the low revolution frequency characteristics of this accelerator, we proposed an acceleration cavity based on the induction-acceleration principle. Comparing with conventional Metal Alloy broad-band cavity, the average accelerating beam current using this type of accelerating cavity can be higher.First, we studied the fast solid-state modulator used for the induction accelerating cavity. The large variation of revolutionary period of particles in the FFAG accelerator requires a cavity with the capability of varying the frequencies simultaneously in the range of the revolutionary frequency. The conventional linear type modulator cannot fulfill this requirement. In this dissertation, we choose the semiconductor switching device based technology which can produce a continuous wave in order of MHz frequency to build to modulator. MOSFET, a commonly used power switching element is used in our research for its advantage of fast switching speed (about 10 ns). After analyzing the circuit, we built a modulator prototype with 5 induction-adders as well as quick synchronized clocking and driving circuits. A testing result of a 3 kV pulsed voltage, a 118 A pulsed current and a 100 ns pulse length have been obtained, and the impulse rise time is short enough for the accelerating the He ion in the FFAG accelerator. Except for in the accelerator area, the solid-state technology developed in this dissertation can also be used in the radar and medical processing areas. In the second part, we designed a racetrack shape cavity used for the FFAG accelerator. Typically, an RF cavity is operated in a fixed frequency, while for the cavity used in the FFAG accelerator, a cavity with rapid frequency tuning capability is required to accelerate the particles in thousands of turns. The RF cavity with a low quality factor can gain a tunable frequency, but its strong wake field and easily breaked up electric field restrict the use of this type of cavity in FFAG. A conceptual design of induction cavity for the FFAG accelerator is given in this part of dissertation. To match the vacuum chamber, a racetrack cross section shape is used. We calculated distributed parameters of this cavity, as well as the accelerating voltage waveform using an equivalent transformer model and a transmission line model. This cavity is designed to have a 5kV accelerating voltage,200 ns pulse length, and the power assumption of 180kW, and to accelerate a beam with a 10 mA average current. The pulse form is adjusted to have a slightly rising tail to minimize the phase delay caused by the unflatten waveform. Due to the asymmetry of the racetrack cavity, the particles with difference transverse coordinate may not be accelerated by a same voltage. Thus we studied the 3D inducted electric field using the code OPERA-3D, and found that the accelerating voltages at different horizontal location are within the accelerator physics design tolerance.The technologies developed in this dissertation demonstrated that it is possible to accelerating charged particles in the FFAG accelerator using the induction type cavity.
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