  Low-energy muon beams are useful for a range of physics experiments. We
consider the production of low-energy muon beams with small energy spreads
using frictional cooling. As the input beam, we take a surface muon source such
as that at the Paul Scherrer Institute. Simulations show that the efficiency of
low energy muon production can potentially be raised to 1%, which is
significantly higher than that of current schemes.
