Expected performance of shintake monitor (IP beam size monitor at ATF2)

Precision beam size monitor, so called Shintake monitor, based on laser interferometer is developed. The installation to the interaction point of ATF2 is on going. The beam size resolution is estimated based on the practical test and it is expected to satisfy the requirement of ATF2. The detail of Shintake monitor at ATF2 and the process of the performance expectation are presented in this article.