An acoustic vortex beam’s wavefield has a null on the axis of propagation and an angular phase ramp. A four-element transducer generates a first order vortex beam in water by appropriately phasing each element [V. Bollen et al., Proc. Meet. Acoust. 19, 070075 (2013)]. A differential beam having a broader null may also be produced by exciting two elements out-of-phase. The four-element transducer was also used to measure backscattering by a small solid sphere scanned in a raster pattern and insonified by the vortex beam. By independently recording each of the four elements and adding appropriate time delays in post-processing, the scattering may be measured in a helicity neutral, and co- and cross-helicity sensitive modes; this allows the retention of the vortex source without modifying the experimental setup. Due to the rapid phase change on the axis of the beam, subwavelength resolution of the null location of the sphere can be achieved. By applying a time delay-and-sum imaging algorithm this resolution can be further increased. Three-dimensional images can also be constructed from the data. By driving two opposing elements, the tilt of the transducer with respect to the scanning plane can be inferred, aiding alignment. [Work supported by ONR.]