  The continue wave (CW) high current proton linac has wide applications as the
front end of the high power proton machines. The low energy part is the most
difficult one and there is no widely accepted solution yet. Based on the
analysis of the focusing properties of the CW low energy proton linac, a 10 MeV
low energy normal conducting proton linac based on equidistant seven-gap
Cross-bar H-type (CH) cavities is proposed. The linac is composed of ten 7-gap
CH cavities and the transverse focusing is maintained by the quadrupole
doublets located between cavities. The total length of the linac is less than 6
meters and the average acceleration gradient is about 1.2 MeV/m. The
electromagnetic properties of the cavities are investigated by Microwave
Studio. At the nominal acceleration gradient the maximum surface electric field
in the cavities is less than 1.3 times Kilpatrick limit, and the Ohmic loss of
each cavity is less than 35 kW. The multi-particle beam dynamics simulations
are performed with the help of the Tracewin code, the results show that the
beam dynamics of the linac is quite stable, and the linac has the capability to
accelerate up to 30 mA beam with acceptable dynamics behavior.
