Antineutrino
From Star Trek : Freedom's Wiki
An antineutrino is a type of particle, the antimatter counterpart to the neutrino.
The starship USS Voyager was bombarded by antineutrinos when Crewman Seska attempted to activate a Sikarian spatial trajector unit on board the ship. The antineutrino bombardment weakened the antimatter containment field of Voyager's warp core, risking a containment breach. (VOY: "Prime Factors")