However, neutrino detectors cannot distinguish perfectly between neutrinos and antineutrinos. Detecting neutrinos proved considerably more difficult than not detecting antineutrinos. If they do, their properties are substantially different from observable neutrinos and antineutrinos. Some of the mSME coefficients lead to mixing between neutrinos and antineutrinos. The question, thus, remains&colon; Do neutrinos and antineutrinos differ only in their chirality? Adding gadolinium to the Super-Kamiokande allows it to distinguish between neutrinos and antineutrinos. Yet all neutrinos have been observed with left-handed "chirality", and all antineutrinos right-handed. It is possible that their counterparts (right-handed neutrinos and left-handed antineutrinos) simply do not exist. If they were to, then what are now called antineutrinos could not be true antiparticles. The KamLAND experiment is a liquid scintillator detector designed to detect reactor antineutrinos. "Ordinary" double beta decay results in the emission of two electrons and two antineutrinos. This releases additional energy in the form of beta particles, antineutrinos, and gamma rays. The first detection of antineutrinos generated in a nuclear reactor was confirmed in 1956. The main background in the geoneutrino measurements are the antineutrinos coming from reactors. Counting antineutrinos produced in the Earth can constrain the geological abundance models.