Design of low energy beam transport for new LANSCE H+ injector

The present LANSCE injector utilizes two 750-keV Cockcroft-Walton (CW) based injectors for simultaneous injection of H+ and H− beams into 800-MeV accelerator. To reduce long-term operational risks, the new project to replace the existing H+ CW injector with a Radio-Frequency Quadrupole (RFQ) accelerator is underway [1]. The new injector requires a Low-Energy Beam Transport (LEBT). An ion source and 2-solenoid magnetic LEBT have been designed and optimized to transport beams over a wide range of space-charge neutralization and transverse emittance, while allowing sufficient space for diagnostics and a beam deflector. The design layout minimizes the beam size in the LEBT and potential emittance growth due to solenoid aberrations and nonlinear space-charge forces. This paper describes the details of the LEBT design activity.