Commissioning of the spallation neutron source front end systems

The Front-End (FE) for the Spallation Neutron Source (SNS) accelerator system is a 2.5-MeV linac injector consisting of the following major subsystems, the rf-driven H- ion source, the electrostatic Low Energy Beam Transport line, a 402.5 MHz RFQ, the Medium Energy Beam Transport line, a beam chopper system and a suite of diagnostic devices. After construction and initial commissioning at LBNL the Front End was shipped to Oak Ridge in the summer of 2002, installed at the SNS site and re-commissioned. This paper provides an overview of the major design features and the experimental results obtained during the final commissioning of the Front End Systems. Performance of the various subsystems will be described, and the final beam output performance will be summarized.