Electromagnetic design of the low beta cavities for the JAEA ADS

The Japan Atomic Energy Agency (JAEA) is designing a superconducting CW proton linear accelerator for the ADS project. The superconducting region will use five types of radio frequency cavities. In the region from 2 to 180 MeV the acceleration will be done using Half Wave Resonator (HWR) and Single Spokes (SS) cavities. HWR cavities will accelerate the beam from 2 to 10 MeV with a geometrical beta of 0.08 and the SS ones will do from 10 to 180 MeV using two cavity families with geometrical betas of 0.16 and 0.43. The results of electromagnetic model design are presented and the comparison with similar cavities from other projects are included.