  Measurements of circular polarization of $\gamma$-ray emitted from neutron
capture reactions provide valuable information for nuclear physics studies. The
spin and parity of excited states can be determined by measuring the circular
polarization from polarized neutron capture reactions. Furthermore, the
$\gamma$-ray circular polarization in a neutron capture resonance is crucial
for studying the enhancement effect of parity nonconservation in compound
nuclei. The $\gamma$-ray circular polarization can be measured using a
polarimeter based on magnetic Compton scattering. A polarimeter was
constructed, and its performance indicators were evaluated using a circularly
polarized $\gamma$-ray beam. Furthermore, as a demonstration, the $\gamma$-ray
circular polarization was measured in
$^{32}$S($\vec{\textrm{n}}$,$\gamma$)$^{33}$S reactions with polarized
neutrons.
