Benchmarking of Multiparticle Phase Scan and Acceptance Scan techniques for the Spallation Neutron Source linac

Abstract

The importance of accurately setting the rf field amplitude and phase, called rf set-point is well received for a high intensity proton linac such as the Spallation Neutron Source (SNS) linac. As a technique to set the rf set-point of the SNS Drift Tube Linac (DTL), multiparticle phase scan technique based on realistic multiparticle tracking was applied and compared with the measurement data. The analysis showed an accurate agreement between the measurement and simulation even when the beam bunch is rather long (the Full Width Half Maximum beam bunch length entering the DTL tank 1 is about 27�a). Benchmarking of the multiparticle phase scan against acceptance scan showed an excellent agreement in the rf set-points obtained from the two techniques. The model was based on the realistic multiparticle tracking including space charge effect and the realistic BPM model unlike the previous works based on single particle tracking.