  A new spin- and angle-resolved inverse photoemission setup with a low-energy
electron source is presented. The spin-polarized electron source, with a
compact design, can decouple the spin polarization vector from the electron
beam propagation vector, allowing to explore any spin orientation at any
wavevector in angle-resolved inverse photoemission. The beam polarization can
be tuned to any preferred direction with a shielded electron optical system,
preserving the parallel beam condition. We demonstrate the performances of the
setup by measurements on Cu(001) and Au(111). We estimate at room temperature
the energy resolution of the overall system to be $\sim170$ meV from
$k_{B}T_{eff}$ of a Cu(001) Fermi level, allowing a direct comparison to
photoemission. The spin-resolved operation of the setup has been demonstrated
by measuring the Rashba splitting of the Au(111) Shockley surface state. The
effective polarization of the electron beam is $P=30\pm3$ \% and the wavevector
resolution is $\Delta k_{F}\lesssim0.06$ \AA$^{-1}$. Measurements on the
Au(111) surface state demonstrate how the electron beam polarization direction
can be tuned in the three spatial dimensions. The maximum of the spin asymmetry
is reached when the electron beam polarization is aligned with the in-plane
spin-polarization of the Au(111) surface state.
