PULSE LENGTHENING EXPERIMENTS ON THE FETS ION SOURCE

The Front End Test Stand (FETS) under construction at the Rutherford Appleton Laboratory is the UK's contribution to research into the next generation of High Power Proton Accelerators (HPPAs). Running at 50 Hz with 2 ms pulse lengths are required. This paper presents initial H beam currents for long pulse lengths. INTRODUTION The FETS ion source [1] is a modified version of the ISIS surface Penning source. Recent work has demonstrated an H beam at the exit of the LEBT with a current in excess of 50 mA and a normalised RMS emittance of 0.35 π mm mrads for a 500 μs pulse length at 50 Hz. Previous studies [2] have shown that it is possible to offset the extra power in the discharge for longer pulses with additional cooling. The following experiments show the beam current results for longer extraction voltage pulses and longer discharges.