  We discuss the design and construction of a novel target array of nonmagnetic
test masses used in a neutron polarimetry measurement made in search for new
possible exotic spin dependent neutron-atom interactions of Nature at
sub\,-$mm$ length scales. This target was designed to accept and efficiently
transmit a transversely polarized slow neutron beam through a series of long
open parallel slots bounded by flat rectangular plates. These openings
possessed equal atom density gradients across the slots from the flat test
masses with dimensions optimized to achieve maximum sensitivity to an exotic
spin-dependent interaction from vector boson exchanges with ranges in the
millimeter to micron regime. The parallel slots were oriented differently in
four quadrants that can be rotated about the neutron beam axis using a Geneva
drive. The spin rotation signals from the 4 quadrants were measured using a
segmented neutron ion chamber in parallel to suppress possible systematic
errors from stray magnetic fields in the target region. Design constraints and
systematic effects are discussed.
