Séminaires, soutenances

Etude d'oscillation de neutrinos avec l'expérience SOLID

par Dr Frederic YERMIA (SUBATECH - Université de Nantes)

Europe/Paris
Description
The disappearance of reactor antineutrino into a new neutral state (called sterile neutrino) has been proposed as a possible explanation for the recent reactor and Gallium anomalies arising from the re-analysis of reactor flux and calibration data of previous neutrino experiments. A way to test this hypothesis is to look for distortions of the anti-neutrino energy caused by oscillation from active to sterile neutrino at close stand-off (~ 6-8m) of a compact reactor core. Due to the small anti-neutrino cross-section, the main challenge in achieving a precise measurement is to control the high level of gamma rays and neutron background that are present at close stand off and to the surface. The SoLid experiment intends to search for active-to-sterile anti-neutrino oscillation at very short baseline of the SCK•CEN BR2 research reactor. A novel approach to measuring reactor anti-neutrinos was developed based on an innovative sandwich of composite Polyvynil-Toluene and 6LiF:ZnS scintillators. The system is highly segmented and read out by a network of wavelength shifting fibers and MPPCs. High experimental sensitivity can be achieved compared to other standard technologies with the combination of high granularity, high neutron-gamma discrimination using 6LiF:ZnS(Ag) scintillator and precise localisation of the Inverse Beta Decay products. This compact system requires limited passive shielding and rely on spatial topology to determine the different class of backgrounds. We will describe the principle of detection, detector design and the expected physics reach of the SoLid experiment. We will focus on the performance of the first full scale SoLid module 1 (SM1) and present the new data taken at BR2 in February 2015. We will conclude on the physics reach of the next phase that will start in mid-2016.
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