Development and Implementation of δ T Procedure for the SNS Linac

The Δt procedure is a time of flight technique for setting the phases and amplitudes of accelerating fields in a multi-cavity linac. It was initially proposed and developed for the LAMPF linac in the early seventies [1,2] and since then has been used in several accelerators [3,4]. The SNS linac includes four CCL modules (Side Coupled Structure) operating at 805 MHz for the energy range from 86.8 MeV up to 185.6 MeV. The Δt procedure has been implemented for the SNS CCL linac and was used for initial beam commissioning of three CCL modules. A brief theory of the procedure, the results of the design parameter calculations and the experimental results of phase and amplitude set points are presented and discussed.