KATRIN

In 2015, the commissioning measurements on this spectrometer were completed, successfully verifying its basic vacuum, transmission and background properties.

In most beta decay events, the electron and the neutrino carry away roughly equal amounts of energy.

The events of interest to KATRIN, in which the electron takes almost all the energy and the neutrino almost none, are very rare, occurring roughly once in a trillion decays.

The experiment reckons it needs 1000 days of measurement to reach target sensitivity of 0.2 eV (upper limit for neutrino mass).

The February 2022 upper limit is mν < 0.8 eV c–2 at 90% CL in combination with the previous campaign.

[11] Along with the possible observation of neutrinoless double beta decay, KATRIN is one of the neutrino experiments most likely to yield significant results in the near future.

Transport of the main spectrometer to the Karlsruhe Institute of Technology .
Illustration of KATRIN beamline and its main components. [ 5 ]
Energy spectrum of the electrons emitted in tritium beta decay. Three graphs for different neutrino masses are shown. These graphs differ only in the range near the high-energetic end-point; the intersection with the abscissa depends on the neutrino mass. In the KATRIN experiment the spectrum around this end-point is measured with high precision to obtain the neutrino mass.
Timeline of neutrino mass measurements by different experiments. [ 5 ]