Guido Drexlin weighs the lightest particles in the Universe. At his Tritium Laboratory in Karlsruhe, Germany, the professor of particle astrophysics has devised scales to gauge the weight of neutrinos. Known as "ghost particles", neutrinos are believed by scientists to form the building blocks of the Universe, but they have long eluded measurement – until now.
Drexlin's Karlsruhe tritium neutrino experiment, known as KATRIN, is a 200-tonne, 70-metre-long line of superconducting magnets and cold traps. It tracks the decay of the radioactive hydrogen isotope tritium, which produces both electrons and neutrinos. While the neutrinos disappear as soon as they are formed, the electrons can be steered by a magnetic field into KATRIN's powerful spectrometer. This controls the speed of travelling particles, allowing Drexlin to analyse their mass as they pass through.
Once he knows the exact mass of the electrons, Drexlin can then deduct it from the mass of the original tritium atom. What's left should, in time, decide the weight of ghost particles.
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In October 2016, when Drexlin watched electrons shoot through KATRIN for the first time, he could only describe it as a "wow" feeling. The resulting data is a promising indication that, over the next five years, the secrets of neutrinos will at last be uncovered. "I am often asked why I gave half my life to neutrinos. It is probably even more - but they are fascinating," he says. "This is what motivates my colleagues and me. With KATRIN, we are researching fundamental innovations."
The experiment marks a huge step towards understanding the dynamics of ghost particles and, in turn, the workings of our Universe. As his machine continues to find new data, Drexlin looks forward to the future. "Hopefully, by 2022, we will have discovered the mass of neutrinos. After only a few days of experimenting with KATRIN, we have already witnessed a mass range of neutrinos that have never been investigated before. It will be an exciting year."
Additional research by Alexandra Simon-Lewis
This article was originally published by WIRED UK
