The Fermilab upgrade linac: Dynamics design process

The Fermilab Coupled Cavity Linac requires dynamics design procedures that predict 805 MHz rf synchronization, non-linear emittance dilution and system error aspects of the device. Full 3-D beam simulations using three separate codes have shown the need for a central orbit monitor to detect desynchronization implicit in the longitudinal dynamics of coupled cavity devices. The new linac section accepts a 116 Mev (200 MHz) DTL beam, requiring a transition matching section, before actual 805 MHz acceleration begins. This requirement places significant constraints on phase space acceptances of the side coupled structure. The authors describe special aspects of the design codes used to verify these system attributes, with particular attention to the effect of system errors and rf noise on the beam performance. Results of beam loss simulations, using a PIC model of beam halo based on current knowledge of the 200 Mev beam is discussed