Tuning of final focus system for future linear colliders

In this paper, the simulation shows that the combination of the alignment by beam method and the linear knobs is a possible tuning method for the start-up of the final focus system of a future linear collider. It allows a conventional level of initial, alignment of the magnets, setting errors and sensitivity of position monitors. On the other hand, it has relies on the spot size monitor at the IP and the accuracy and the stability of the magnet movers. It is not necessary for the magnet movers to have an ability to set the position in the sub-micron accuracy, because the authors can use a correction dipole instead of such a small displacement of a quadrupole. In this simulation they used about 400 pulses to tune up entire beam line. Since the linear collider has a few hundred Hz repetition rate, the actual speed of the tuning is limited by the response of the movers and the monitors. This means that in the actual situation, they can use more pulses to determine the displacement of the magnets and the minimum search than in the simulation. Therefore the accuracy of the method may become even better than the simulation