The key physics and technology issues in the intense-beam proton accelerators

Beam power is required to raise one order in the next generation spallation neutron source. There are still some physics and technology difficulties need to be overcome, even though no fatal obstacle exists due to the rapid development of the technology in intense-beam accelerator in recent years. Therefore, it is highly demanded to clarify the key issues and to lunch an R and D program to break through the technological barriers before start to build the expansive machine. The new technological challenge arises from the high beam current, the high accelerator power and the high demand on the reliability and stability of the accelerator operation. The will discuss these issues and the means to resolve them, as well as the state of the art in a few of major technological disciplines. Finally, the choice the framework of intense-beam accelerator is discussed