Effects of machine errors on the ILC main linac

For a practical linac, the beam property is affected seriously by any machine imperfections. In this paper, the effects of several main errors in the ILC main linac, such as quadrupole misalignment, magnet strength error and cavity misalignment, were studied by a theoretical method. The tolerance for each error was also obtained. Comparison with the numerical simulation result is made and the agreement is quite good.