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Borexino
Borexino is a deep underground particle physics experiment to study low energy (sub-MeV) solar neutrinos. The detector is the world's most radio-pure liquid scintillator calorimeter and is protected by 3,800 meters of water-equivalent depth (a volume of overhead rock equivalent in shielding power to that depth of water). The scintillator is pseudocumene and PPO which is held in place by a thin nylon sphere. It is placed within a stainless steel sphere which holds the photomultiplier tubes (PMTs) used as signal detectors and is shielded by a water tank to protect it against external radiation. Outward pointing PMT's look for any outward facing light flashes to tag incoming cosmic muons that manage to penetrate the overburden of the mountain above. Neutrino energy can be determined through the number of photoelectrons measured in the PMT's. While the position can be determined by extrapolating the difference in arrival times of photons at PMT's throughout the chamber.
The primary aim of the experiment is to make a precise measurement of the individual neutrino fluxes from the Sun and compare them to the Standard solar model predictions. This will allow scientists to test and to further understand the functioning of the Sun (e.g., nuclear fusion processes taking place at the core of the Sun, solar composition, opacity, matter distribution, etc.) and will also help determine properties of neutrino oscillations, including the MSW effect. Specific goals of the experiment are to detect beryllium-7, boron-8, pp, pep and CNO solar neutrinos as well as anti-neutrinos from the Earth and nuclear power plants. The project may also be able to detect neutrinos from supernovae within our galaxy with a special potential to detect the elastic scattering of neutrinos onto protons, due to neutral current interactions. Borexino is a member of the Supernova Early Warning System. Searches for rare processes and potential unknown particles are also underway.
The name Borexino is the Italian diminutive of BOREX (Boron solar neutrino Experiment), after the original 1 kT-fiducial experimental proposal with a different scintillator (TMB), was discontinued because of a shift in focus in physics goals as well as financial constraints. The experiment is located at the Laboratori Nazionali del Gran Sasso near the town of L'Aquila, Italy, and is supported by an international collaboration with researchers from Italy, the United States, Germany, France, Poland, Russia and Ukraine. The experiment is funded by multiple national agencies; the principal ones are INFN (National Institute for Nuclear Physics, Italy) and NSF (National Science Foundation, USA).
The SOX experiment was a sub-project designed to study the possible existence of sterile neutrinos or other anomalous effects in neutrino oscillations at short ranges through the use of a neutrino generator based on radioactive cerium-144 placed under the water tank of the Borexino detector. This project was cancelled in early 2018 due to the cancellation in 2017 of the contract for cerium-144 by the Russian Mayak fuel reprocessing plant. The cancellation is thought to be connected to the anomalous airborne radioactivity increase in Europe during the autumn of 2017, whose source was eventually localized to the Mayak reprocessing plant.
The entire Borexino experiment was terminated in October 2021.
The initial BOREX proposal was made in 1986. In 1990, the design was fundamentally altered, and the name of the experiment was changed to "Borexino". Research and development began on the detector at that time. By 2004, the structure of the detector had been completed, and by May 2007 the detector chamber had been filled and data taking began.
The first results by the collaboration were published in August 2007 in: "First real time detection of 7Be solar neutrinos by Borexino". The subject was further extended in 2008. In 2010, "geoneutrinos" from Earth's interior were observed for the first time using Borexino. These are anti-neutrinos produced in radioactive decays of uranium, thorium, potassium, and rubidium, although only the anti-neutrinos emitted in the 238U/232Th chains are visible because of the inverse beta decay reaction channel Borexino is sensitive to. That year, the lowest-threshold (3 MeV) measurement of the 8B solar neutrino flux was also published. Additionally, a multi-source detector calibration campaign took place, where several radioactive sources were inserted in the detector to study its response to known signals which are close to the expected ones to be studied. In 2011, the experiment published a precision measurement of the beryllium-7 neutrino flux, as well as the first evidence for the pep solar neutrinos.
The results of measurements of the speed of CERN Neutrinos to Gran Sasso were published in 2012. These results were consistent with the speed of light, thus providing confirmation that the Faster-than-light neutrino anomaly reported earlier in the year was an erroneous measurement. An extensive scintillator purification campaign was also performed, achieving the successful goal of further reducing the residual background radioactivity levels to unprecedented low amounts (up to 15 orders of magnitude under natural background radioactivity levels).
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Borexino AI simulator
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Borexino
Borexino is a deep underground particle physics experiment to study low energy (sub-MeV) solar neutrinos. The detector is the world's most radio-pure liquid scintillator calorimeter and is protected by 3,800 meters of water-equivalent depth (a volume of overhead rock equivalent in shielding power to that depth of water). The scintillator is pseudocumene and PPO which is held in place by a thin nylon sphere. It is placed within a stainless steel sphere which holds the photomultiplier tubes (PMTs) used as signal detectors and is shielded by a water tank to protect it against external radiation. Outward pointing PMT's look for any outward facing light flashes to tag incoming cosmic muons that manage to penetrate the overburden of the mountain above. Neutrino energy can be determined through the number of photoelectrons measured in the PMT's. While the position can be determined by extrapolating the difference in arrival times of photons at PMT's throughout the chamber.
The primary aim of the experiment is to make a precise measurement of the individual neutrino fluxes from the Sun and compare them to the Standard solar model predictions. This will allow scientists to test and to further understand the functioning of the Sun (e.g., nuclear fusion processes taking place at the core of the Sun, solar composition, opacity, matter distribution, etc.) and will also help determine properties of neutrino oscillations, including the MSW effect. Specific goals of the experiment are to detect beryllium-7, boron-8, pp, pep and CNO solar neutrinos as well as anti-neutrinos from the Earth and nuclear power plants. The project may also be able to detect neutrinos from supernovae within our galaxy with a special potential to detect the elastic scattering of neutrinos onto protons, due to neutral current interactions. Borexino is a member of the Supernova Early Warning System. Searches for rare processes and potential unknown particles are also underway.
The name Borexino is the Italian diminutive of BOREX (Boron solar neutrino Experiment), after the original 1 kT-fiducial experimental proposal with a different scintillator (TMB), was discontinued because of a shift in focus in physics goals as well as financial constraints. The experiment is located at the Laboratori Nazionali del Gran Sasso near the town of L'Aquila, Italy, and is supported by an international collaboration with researchers from Italy, the United States, Germany, France, Poland, Russia and Ukraine. The experiment is funded by multiple national agencies; the principal ones are INFN (National Institute for Nuclear Physics, Italy) and NSF (National Science Foundation, USA).
The SOX experiment was a sub-project designed to study the possible existence of sterile neutrinos or other anomalous effects in neutrino oscillations at short ranges through the use of a neutrino generator based on radioactive cerium-144 placed under the water tank of the Borexino detector. This project was cancelled in early 2018 due to the cancellation in 2017 of the contract for cerium-144 by the Russian Mayak fuel reprocessing plant. The cancellation is thought to be connected to the anomalous airborne radioactivity increase in Europe during the autumn of 2017, whose source was eventually localized to the Mayak reprocessing plant.
The entire Borexino experiment was terminated in October 2021.
The initial BOREX proposal was made in 1986. In 1990, the design was fundamentally altered, and the name of the experiment was changed to "Borexino". Research and development began on the detector at that time. By 2004, the structure of the detector had been completed, and by May 2007 the detector chamber had been filled and data taking began.
The first results by the collaboration were published in August 2007 in: "First real time detection of 7Be solar neutrinos by Borexino". The subject was further extended in 2008. In 2010, "geoneutrinos" from Earth's interior were observed for the first time using Borexino. These are anti-neutrinos produced in radioactive decays of uranium, thorium, potassium, and rubidium, although only the anti-neutrinos emitted in the 238U/232Th chains are visible because of the inverse beta decay reaction channel Borexino is sensitive to. That year, the lowest-threshold (3 MeV) measurement of the 8B solar neutrino flux was also published. Additionally, a multi-source detector calibration campaign took place, where several radioactive sources were inserted in the detector to study its response to known signals which are close to the expected ones to be studied. In 2011, the experiment published a precision measurement of the beryllium-7 neutrino flux, as well as the first evidence for the pep solar neutrinos.
The results of measurements of the speed of CERN Neutrinos to Gran Sasso were published in 2012. These results were consistent with the speed of light, thus providing confirmation that the Faster-than-light neutrino anomaly reported earlier in the year was an erroneous measurement. An extensive scintillator purification campaign was also performed, achieving the successful goal of further reducing the residual background radioactivity levels to unprecedented low amounts (up to 15 orders of magnitude under natural background radioactivity levels).
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