KATRIN

KATRIN, the Karlsruhe Tritium Neutrino Experiment, is a large-scale physics facility at the Karlsruhe Institute of Technology (KIT) in Germany, built to measure the mass of one of the universe's most elusive particles.

About KATRIN

KATRIN examines the beta decay of tritium to measure the mass of the electron antineutrino with sub-eV precision. At its core is a 200-ton spectrometer, and it is a recognised CERN experiment, designated RE14.

History

Commissioning measurements on the spectrometer were completed in 2015, confirming its vacuum, transmission, and background properties. Testing began in October 2016, and the experiment was formally inaugurated on 11 June 2018, followed by a first tritium engineering run that summer. The first science measurements took place on 10 April 2019.

Research

In February 2022, KATRIN announced an upper limit on the antineutrino mass of 0.8 eV/c² at 90% confidence. In April 2025, that result was tightened to 0.45 eV/c² at the same confidence level, among the most precise direct neutrino mass measurements to date.

Location & getting there

KATRIN is housed at the Karlsruhe Institute of Technology in Germany. As a working physics experiment rather than a public viewing site, access is generally arranged through KIT rather than casual visits.

Visiting KATRIN

KATRIN is a research facility, not a public observatory; check the Karlsruhe Institute of Technology's official channels for any tours or open-day events before planning a visit.

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