At 11:26 am of Oct. 7, 2021 Borexino DAQ has come to an end. After that, the detector decommissioning phase has begun.
In the picture (see also the video below) our Run Coordinator, Chiara Ghiano, and one of our technicians, Massimo Orsini, responsible for maintenance of the electronics and PMTs, stop the last run of the DAQ (#36744) and then turn off the PMTs… for the very last time.
This marks the end of the Borexino detector. Since today there will be no more new data. But the long endeavor of the Borexino collaboration is not over yet. There is still work to be done with the data collected so far: new analysis to be performed, and more results to be published. Stay tuned!
Here follows the official news from the LNGS:
Gran Sasso National Laboratories, 7 October 2021 – Borexino’s great scientific adventure ends today. Active since 2007, the experiment of the Gran Sasso National Laboratories (LNGS) of the National Institute of Nuclear Physics (INFN) has allowed us to increase our knowledge on the functioning of the Sun, and on the neutrinos produced by the fusion reactions that take place in its nucleus.
Designed at the end of the 1980s by Gianpaolo Bellini and Frank Calaprice, its creation was the result of a great international collaboration and required many years to develop extremely refined material purification techniques, which still today makes Borexino an experiment of unparalleled sensitivity in this field of research.
In these 14 years of operation, the scientific results achieved by Borexino have been of the highest level and have gone far beyond what had been hypothesized in the design phase. Among the main ones we remember the detection of neutrinos produced in the proton-proton nuclear reaction, which produces 99% of the Sun’s energy (2014); in 2020 the first observation of neutrinos coming from the CNO cycle of the Sun, which is of great importance especially for high-mass stars. Both of these discoveries earned the experiment the covers of the most authoritative international scientific journals and the inclusion in the Top Ten of the most important physics results of the Physics World magazine. The contribution that Borexino has given also to geophysics is of notable importance: since 2010 the experiment has been able to reveal the so-called geoneutrinos, i.e. the neutrinos produced by radioactive decays in the rocks of the Earth’s mantle, demonstrating that a considerable part of the heat produced inside the Earth derives from the radioactive decay of uranium-238 and thorium-232 present in its mantle.
This great adventure comes to the end today. The preparation for the shutdown of the Borexino detector, the extraction of the scintillator and its transportation to an authorized disposal plant are the result of scrupulous planning shared with the local authorities. The decommissioning of Borexino will take place according to the highest safety standards and under the constant monitoring of a dedicated team of specialized engineers and technicians.