Speaker
Description
The neutrino spectra and flux were reevaluated during the preparation of the current experiments devoted to the measurement of $\theta_{13}$. Some discrepancies between data and the theoretical predictions in some neutrino experiments at short distances were observed when using the new predicted flux and spectra. This problem has been called the Reactor Antineutrino Anomaly (RAA), which together with the gallium anomaly, both show discrepancies with respect to the expectations at the $\sim$ 3 $\sigma$ level. Oscillations into a light sterile neutrino state ($\Delta m^{2} \sim 1eV^{2}$) could account for such deficits. The SoLid experiment has been conceived to give an unambiguous response to the hypothesis of a light sterile neutrino as the origin of the RAA. To this end, SoLid is searching for an oscillation pattern at short baselines (5-9 m) in the energy spectrum of the electron antineutrinos emitted by the SCK•CEN BR2 reactor in Belgium.
The detector uses a novel technology, combining PVT (cubes of 5 cm3) and $^6$LiF:ZnS (sheets) scintillators. The PVT acts as an antineutrino target for Inverse Beta Decay (IBD) process, which yields a positron plus a neutron. The positron interacts mostly in the PVT, while the neutron thermalize and is captured some $\mu$s later on the $^6$Li, giving rise to a prompt-delayed signal correlated in time and distance.
The detector is highly segmented (modules of 10 planes of 16x16 cubes), and is read out by a network of wavelength shifting fibers and MPPCs. Then, high experimental sensitivity can be achieved, which allows to the precise localization of the IBD products, increasing the power of the background discrimination through topological cuts. A 300 kg prototype was deployed in 2015, showing the feasibility of the detection principle. A full scale detector (~2 tons) is currently under construction and data taking with the first detector modules will start by summer of 2017.
