Within the 70-meter (230-foot) chamber, tritium gas decays into helium, an electron and an electron antineutrino, while a huge, sensitive spectrometer probes the results.īecause neutrinos are so ghostly, it's not possible to measure them. Physicists have named these neutrinos mass 1, mass 2, and mass 3, though they can also be referred to as 1, 2, and 3. But there is another way to think about neutrinostheir mass, or mass state. KATRIN leverages the beta decay of an unstable radioactive isotope of hydrogen called tritium to probe the mass of a neutrino. Electron neutrinos interact to make electrons, muon neutrinos make muons, and tau neutrinos make taus. You can't just grab a tiny scale, plop a neutrino on it, and call it a day. Unfortunately, it's also very hard to do. Thus the energy difference between the Q value and the. But, if we can obtain a measurement of this property, there will be so much more we can learn about the Universe. The energy of the Q value is distributed to the emitted neutrino and the excitation of the Dy atom.

We do have some methods for detection – such as Cherenkov neutrino detectors – but these are indirect, catching the effects of the passing neutrinos, rather than the neutrinos themselves.Īll this means that measuring the near-zero mass of these particles is a particularly tough challenge. It also makes them incredibly difficult to detect. But this raises certain theoretical problems and there have been many attempts to set a range for the mass of the neutrino. One electron, for example, has a mass of 511,000 electronvolts. This is why we call them ghost particles. According to current best estimates, the sum of the three neutrinos’ masses should be less than one electronvolt.

Mass of electron neutrino