Direct-current proton-beam measurements at Los Alamos

Abstract

Recently, a CW proton accelerator complex was moved from Chalk River Laboratories (CRL) to Los Alamos National Laboratory. This includes a 50‐keV dc proton injector with a single‐solenoid low‐energy beam transport system (LEBT) and a CW 1.25‐MeV, 267‐MHz radiofrequency quadrupole (RFQ). The move was completed after CRL had achieved 55‐mA CW operation at 1.25 MeV using 250‐kW klystrode tubes to power the RFQ. These accelerator components are prototypes for the front end of a CW linac required for an accelerator‐driven transmutation linac, and they provide early confirmation of some CW accelerator components. The injector (ion source and LEBT) and emittance measuring unit are installed and operational at Los Alamos. The dc microwave ion source has been operated routinely at 50‐keV, 75‐mA hydrogen‐ion current. This ion source has demonstrated very good discharge and H2 gas efficiencies, and sufficient reliability to complete CW RFQ measurements at CRL. Proton fraction of 75% has been measured with 550‐W discharge power. This high proton fraction removes the need for an analyzing magnet. Proton LEBT emittance measurements completed at Los Alamos suggest that improved transmission through the RFQ may be achieved by increasing the solenoid focusing current. Status of the final CW RFQ operation at CRL and the installation of the RFQ at Los Alamos will be given.