At the Fermi National Accelerator Laboratory (Fermi Lab), one of the most distinguished institutions in the development of particle physics, Building the last of the great detectors to study neutrinos and search for evidence of physics beyond the Standard Model. The detector array is being developed as part of the Short-Baselina Neutrino Program.
The design consists of a neutrino source and three detectors in a straight line. The short baseline near-detector (SBND), which is just beginning, will be 110 meters from the region where the proton flux will hit the target, generating a flux of muon neutrinos. MicroBooNE is located 360 meters behind SBND. This device began operating in 2015. Behind MicroBooNE, at a distance of 130 meters, stands ICARUS, which will begin work later this fall.
The neutrino traveling through space undergoes oscillations, it changes between three different types: the muon, the tau, and the electron. It is these oscillations that SBND, MicroBooNE and ICARUS have to study. If it turns out that there is a fourth type of neutrino, or if the neutrinos being studied behave differently than is currently expected, detectors should detect it and perhaps physics will move beyond the Standard Model.
The sensors of the SBND detector will be suspended in a liquid argon tank. When the neutrino enters the tank and collides with an argon atom, many particles and light will be produced. They will be recorded by sensors, and analysis of the signals will allow physicists to accurately recreate the trajectory of all particles from the collision. We will see an image that will show us a huge amount of detail in a very small caliber. Compared to previous experiences, we will truly open up a new spectrum of possibilitiessays Ann Shoecraft, technical coordinator of the project.
There will be three large electrodes inside the SBND. Two anodes and a cathode. Each of them will measure 5 x 4 metres. The electric field strength between the cathode and each anode will be 500 W/cm. The anodes will be placed on the opposite walls of the cubic room. They will pick up electrons, and sensors behind them will record photons. A chip that acts as a cathode will be placed inside the detector. It was installed at the end of July, and the first anode will be completed in the coming days.
When completed, it will weigh more than 100 tons and will be filled with argon at -190°C. The chamber will be placed in a steel cooling system with insulated walls, the function of which is to maintain a low temperature inside. The complex piping system will continuously filter the argon to keep it clean.
SBND is an international institution. Individual elements of the system are created in many countries, mainly in the USA, Great Britain, Brazil and Switzerland. Schukraft expects that the new detector will be launched in early 2023.
When work on SBND is completed, the detector will work with MicroBooNE and ICARUS. First of all, scientists want to look for evidence of a sterile neutrino, a particle that does not interact with the weak force. Earlier, during experiments with the liquid strobe neutrino detector at Los Alamos National Laboratory and MiniBooNE at Fermilab, signals were detected that could indicate the presence of such a particle.
The idea is to bring the detector very close to the neutrino source, in hopes of catching that type of neutrino. Then there is another detector and then another detector. We hope to see sterile neutrino oscillationsExplains Robert Acciari, co-director of the detector’s construction business.
