The vacuum chamber for the main spectrometer of the Karlsruhe TRItium Neutrino Experiment is being manoeuvred after delivery on the Rhine through Eggenstein-Leopoldshafen, November 25, 2006, Photograph: Markus Breig. KIT Archives 28010/I 7185.
What is the mass of a neutrino? The standard model of elementary particles suggests nil. The overall established view in theoretical particle physics depicts neutrinos as massless, electrically neutral components. However, experimental research has revealed that neutrinos do possess mass, albeit millions of times smaller than the next lightest known particles. This fact, combined with neutrinos’ ability to traverse matter almost unimpeded as “ghost particles,” makes measuring their mass extremely challenging. Yet, this value is of far-reaching relevance: neutrinos have populated the early universe in vast numbers since shortly after the Big Bang. Today there are over 330 particles per cubic centimeter, making them billions of times more prevalent than atoms and with their small but non-zero mass have influenced the development of the cosmos. The Karlsruhe Tritium Neutrino Experiment (KATRIN) at KIT is an international collaboration, addressing the neutrino mass question posed in 1930 at a big-science research facility. KATRIN conducts precision spectroscopy of electrons from tritium beta decay. The approximately 70-meter-long, technologically advanced facility was constructed on KIT’s North Campus over a period of more than 15 years, commencing measurements in 2018. The Karlsruhe Tritium Laboratory was crucial in its realization, providing expertise and laboratory infrastructure for carrying out KATRIN. The spectrometer’s ultra-high vacuum tank, 23 meters in length and 10 meters in diameter, is a striking feature of the facility, rivaling an apartment building in size. This 200-ton stainless steel tank, manufactured in Deggendorf near Passau, undertook an unusual journey to Karlsruhe via the Danube, to circumnavigate Europe by ship, and continue up the Rhine. Its spectacular entry through Eggenstein-Leopoldshafen on the final leg of its journey to the then Karlsruhe Research Center in autumn 2006 drew 30,000 spectators and is likely still remembered by many. Kathrin Valerius
KATRIN is a unique research installation worldwide, for which KIT offers ideal prospects of success. This experiment about the foundations of physics shows that we often need complex apparatus to track down the tiniest particles. Kathrin Valerius, co-spokeswoman of the KATRIN Collaboration