OpenMC/tests/test_source_angle_mono/settings.xml

<?xml version="1.0"?>
<settings>

  <eigenvalue>
    <batches>10</batches>
    <inactive>5</inactive>
    <particles>1000</particles>
  </eigenvalue>

  <source>
    <space type="box" parameters="-4 -4 -4  4  4  4" />
    <angle type="monodirectional" parameters="1 0 0" />
  </source>

</settings>