  Radiofrequency spin flippers (RFSF) are key elements of Neutron Resonance
Spin Echo (NRSE) spectrometers, which allow performing controlled manipulations
of the beam polarization. We report on the design and test of a new type of
RFSF which originality lies in the new manufacturing technique for the static
coil. The largely automated procedure ensures reproducible construction as well
as an excellent homogeneity of the neutron magnetic resonance condition over
the coil volume. Two salient features of this concept are the large neutron
window and the closure of the coil by a $\mu$-metal yoke which prevents field
leakage outside of the coil volume. These properties are essential for working
with large beams and enable new applications with coils tilted with respect to
the beam axis such as neutron Larmor diffraction or the study of dispersive
excitations by inelastic NRSE.
