Accelerator Seminar

Simulations on operation of the new UNILAC post-stripper with intense proton beams: longitudinal phase advances below and beyond 90

by Anna Rubin (GSI, Darmstadt)

KBW Hörsaal & Zoom

KBW Hörsaal & Zoom


High intensity beams may suffer from serious beam quality degradation if the focusing scheme allows for occurrence of resonances or instabilities. For transverse focusing a commonly accepted and respected lattice design rule is to choose the phase advance per structure period below the 90deg resonant stopband, which was implicitly applied to the longitudinal phase advance the same way. A recent study pointed out that for lattice structures with more than one rf gap per period the 90deg restriction needs not to be applied the same way to the longitudinal focusing as to the transverse one , thus offering more design flexibility. The present investigation is motivated by an interest to accelerate intense proton beams above longitudinal 90deg in the new post-stripper drift tube linac of the GSI UNILAC by using the rf power supplies optimized for the much stiffer heavy ions.