  In this work we present an alternative way to look at electron diffraction in
a transmission electron microscope. In stead of writing the scattering
amplitude in Fourier space as a set of plane waves, we use the cylindrical
Fourier transform to describe the scattering amplitude in a basis of orbital
angular momentum (OAM) eigenstates. We show how working in this framework can
be very convenient when investigating e.g. rotation and screw axis symmetries.
For the latter we find selection rules on the OAM-coefficients that
unambiguously reveal the handedness of the screw axis. Detecting the
OAM-coefficients of the scattering amplitude thus offers the possibility to
detect the handedness of crystals without the need for dynamical simulations,
the thickness of the sample nor the exact crystal structure. We propose an
experimental setup to measure the OAM-components where an image of the crystal
is taken after inserting a spiral phase plate in the diffraction plane and
perform mulsti-slice simulations on $\alpha$-quartz to demonstrate how the
method indeed reveals the chirality. Experimental feasibility of the technique
is discussed together with its main advantages with respect to chirality
determination of screw axes. The method shows how the use of a spiral phase
plate can be extended from a simple phase imaging technique to a tool to
measure the local OAM-decomposition of an electron wave, widening the field of
interest well beyond chiral space group determination.
