Multiturn Injection

Several schemes are considered for transverse multiturn injection into storage rings. Careful attention is paid to geometry and timing of the emittance and acceptance ellipses, while the septum is taken as a line in phase space. The relative shape of input emittance to acceptance is varied, as well as the tune (integer + 1/n) to obtain, before space charge, zero particle loss and minimum dilution D = ¿A/N¿i, where N = number of injected turns, ¿A is the machine acceptance, and ¿i is the input emittance. Displacement of the IEO by a 4 kick bumper is idealized. The theoretical results for N up to 25 give per-plane dilutions between 1.3 and 2.0. A particle simulation of three schemes to see space charge distortion uses a fast Fourier transform with thin lenses for quadrupoles; wall image is not included. Particle loss on the septum and at the walls is noted and compared. For currents at the conventional space charge limit of the ring, the space charge is a key element in scheme selection.