The directories 001 and 100 contain the Fourier transform µSR spectra for each of these orientations at 5 K.

The experimentally measured spectra are contained in the 'data' subdirectories
The temperatures and fields for which each of these spectra correspond to is included in the filename

The simulated spectra are in the 'simulation' subdirectories.
The first part of the filenames refers to the magnetic structure for which these have been calculated for.
'1a' or '1b' refers to which of the magnetically distinct versions of site 1 these spectra correspond to.
The data has the format 
Magnetic field at muon site (T), Fourier amplitude (arbitrary units)