Calculation of the Orbit Length Change of the Recycler due to Main Injector Ramp

Orbit length of a beam in the Recycler changes during the Main Injector ramps. Unknown kicks from the effects generated by a stray field distribute around the ring. Particularly we observed additional effects from the MI lambertsons and the C-magnets during their ramps for a beam transfer. To estimate the changes, simulated virtual kicks are created in the Recycler lattice. The difference of the orbit lengths is calculated by comparing the horizontal closed orbit of the beam with a reference orbit. Calculation results show that strong effect came from the buses. In this report, we describe the calculation methods. Also presented are the analysis including the calculation of the orbit length changes and the strength of the simulated kicks before and after we shield the buses.