In this case they are detecting inverse beta decay events. The antineutrino interacts with a proton producing a positron and a neutron. The positron annihilates

In this case they are detecting inverse beta decay events. The antineutrino interacts with a proton producing a positron and a neutron. The positron annihilates with an electron producing two gamma rays and the neutron then captures on a proton and releases a 2.22 MeV gamma ray. I think the only realistic way to determine the direction is by looking at the direction of the neutron by comparing the position of the positron annihilation with the neutron capture, but typically the neutron scatters so much in these detectors that it is not possible to do on an event by event basis (although see [0] for a possible detector that could). What you're talking about is elastic scattering and I think this may be possible (see [1]), but I don't know of anyone who is able to do this at these low energies. As a side note, the WATCHMAN collaboration has been studying the ability to monitor nuclear reactors using these sorts of detectors for a while. [0] https://arxiv.org/pdf/1410.8530.pdf https://arxiv.org/pdf/1410.8530.pdf [1] https://www.osti.gov/servlets/purl/1332127 https://www.osti.gov/servlets/purl/1332127