Control survey and analysis for the KEK e-/e+ injector linac.

A control survey technique using a laser tracker and a digital level was introduced to the KEK e-/e+ injector linac in 2020. Control surveys are continuously demonstrated during the machine's downtimes every summer. Analysis of the two-year data reproduces their trends in terms of the fiducial points on the beam line. In our paper, we report on systematic coordinates and their error distributions evaluated by a control survey, compare them with a numerical survey simulation, and discuss newly encountered issues.