Features of a Deutron Accelerator Based on the RFQ Structure

Abstract

In the case of acceleration of particles with a charge-to-mass ratio of 1 : 2, the length of the cavity is practically doubled compared to a proton accelerator for the same energy. At an output energy exceeding 1.0 MeV per nucleon, the cavity length becomes large L_cav ≈ 3 λ, where λ is the wavelength of the TE211 working mode, which leads to a critically small frequency separation between the working TE211 quadrupole mode and the TE11n dipole modes. For mode separation, it is proposed to use coupling windows between neighboring cavity segments, which in turn change the field distribution along the cavity. Uniformity is restored with the help of plungers located along the cavity in each of the 4 segments. The result of the work is the calculation of the RFQ accelerating cavity with the following main parameters: ion type – deuterons or He⁺⁺, operating frequency 202 MHz, injection energy 75 keV, length 4.3 m, pulse power not more than 300 kW, energy of accelerated ions 1.25 MeV/nucleon, pulse current of deuterons 50 mA and He⁺⁺ 10 mA. Based on the performed electrodynamic and beam dynamics calculations, the RFQ cavity was designed.