Weighing the invisible, the challenge of the KATRIN project
An international experiment that has already broken several records. The KATRIN project (KArlsruhe TRItium Neutrino Experiment), led by KIT–Karlsruhe Institute of Technology in Germany and involving 20 institutions from seven different countries, including the Politecnico di Milano, celebrated the achievement of 1,000 days of neutrino measurements with the inauguration of phase 2 of the project: the commissioning of a new and more sophisticated detector, TRISTAN. The RadLab group of the Department of Electronics, Information and Bioengineering, led by professors Carlo Fiorini and Marco Carminati (the latter being the national coordinator for the experiment), also supported by the National Institute for Nuclear Physics, made a significant contribution to the creation of the new detector by designing and developing the detection modules and the low-noise, highly compact readout electronics of the SDD detector.
The adoption of the new detector will allow KATRIN to address a second scientific challenge, namely the search for a hypothetical fourth type of neutrino, known as “sterile”, as it is even more elusive than the other three. The TRISTAN detector upgrade will in fact make it possible to explore a broader parameter space compared to what is currently achievable, as demonstrated by the publication of the project’s first results in the journal Nature.
In this way, it will be possible to search for traces of this hypothetical particle within a range of values (mass on the order of keV, i.e. one thousand electronvolts, and mixing angle of one part per million) that would make it a promising candidate for explaining dark matter. Precisely identifying the neutrino mass, and finding the sterile neutrino, would be two fundamental objectives confirming that the current description of matter and standard interaction forces between particles is incomplete.
Marco Carminati, Professor of Electronics
Gallery
The team from DEIB with the publication in Science: starting from the left, Korbinian Urban, Marco Carminati and Carlo Fiorini
Detection module TRISTAN with monolithic array of 166 SDD
Array of 9 detection modules for a total of 1494 spectroscopic pixels
The international team that developed the TRISTAN detector
TRISTAN - Technical data
The TRISTAN detector consists of an array of 9 detection modules, each composed of a monolithic array of 166 Silicon Drift Detectors, for a total of 1494 spectroscopic pixels. This type of detector, invented in the 1980s by Emilio Gatti, Professor Emeritus of the Politecnico, is well established for X-ray detection, particularly in spectroscopic applications. The novelty of this project is the use of SDD arrays for electron spectroscopy. Furthermore, it is the largest array of detectors of this type ever built.