  Using laser accelerated protons or ions for various applications - for
example in particle therapie or short-pulse radiographic diagnostics - requires
an effective method of focusing and energy selection. We derive an analytical
scaling for the performance of a solenoid compared with a doublet/triplet as
function of the energy, which is confirmed by TRACEWIN simulations. The scaling
shows that above a few MeV a solenoid needs to be pulsed or super-conducting,
whereas the quadrupoles can remain conventional. The transmission of the
triplet is found only 25% lower than that of the equivalent solenoid. Both
systems are equally suitable for energy selection based on their chromatic
effect as is shown using an initial distribution following the RPA simulation
model by Yan et al.\cite{yan2009}.
