  The two cooling channels based on the RFOFO ring concept are considered and
simulated. One of them is the RFOFO helix, also known as the Guggenheim. The
helical shape of the channel resolves the injection and extraction issues as
well as the absorber overheating issue. The issue of the RF breakdown in the
magnetic field is addressed in the so-called open cavity cooling channel
lattice with magnetic coils in the irises of the RF cavities. The details of
the tracking studies of both channels are presented and compared to the
performance of the original RFOFO cooling ring design.
