Estimation of the Longitudinal Impedance of the ATF Damping Ring

Abstract WI,(S) for the bunch with an arbitrary longitudinal charge In order to estimate the possibility of bunch lengthen-distribution X(s) as ing in t,he ATF damping ring, the longitudinal broadband impedance of the ring was evaluated. The inductance was so small, that the bunch lengthening should not be ob-served in the ATF damping ring. q(s) = $-m J ds ’ X ( s- s’) W,/“) ( s’) II.2 (1) The longitudinal impedance Z,,(w) is the Fourier I. INTRODUCTION transform of the longitudinal wake function W,[“)(s); As a check point to the Japan Linear Collider (JLC) [I], it is planned to construct Accelerator Test Facility (ATF). The damping ring, one of the main parts of ATF, has the almost same as that of JLC design. The vacuu