Speaker
Description
DANSS is a detector of reactor antineutrinos based on solid state scintillator
placed on a movable platform below the core of 3.1 GW industrial reactor of Kalininskaya NPP. DANSS detects up to 5000 neutrino events per day with the only 2% background. DANSS is collecting data for 6 years with more than 6 million inverse beta-decay events already collected. The primary goal of the experiment is the sterile neutrino search with reactor neutrinos. The main drawback of the current design is a moderate energy resolution of 34% at 1 MeV. This limits our sensitivity especially in the region of larger delta m^2. An upgrade of the detector is aimed at energy resolution of 12% at 1 MeV. It will also include a 70% increase of the sensitive volume while keeping the same passive shielding and the platform. The main idea of the upgrade is in a new design of the scintillator strips providing larger light output with much better uniformity. Double end readout of the new strips will allow to reconstruct all three coordinates even if only a single strip was hit. The strip prototypes were manufactured and tested at the pion beam of the PNPI synchrocyclotron. More than twice higher light output together with fairly flat detector response uniformity were obtained. To ensure better time response of new strips we are going to use newer wavelength shifting (WLS) fibers YS-2 by Kuraray. These fibers were tested in a dedicated study with a 360 nm picosecond laser pulses and demonstrate nearly twice shorter decay time (4.0 ns) compare to a mature Y-11 fibers. Light output of YS-2 and Y-11 fibers was also compared using 90Sr source and cosmic rays and the new fibers turned out to be at least as good as the mature ones.
The upgrade timescale planned is two years. Mass production of the new strips has already started. The talk covers the detector design and expected sensitivity, as well as the beam test of the new strips and the study of the new WLS fibers.
| Collaboration | DANSS |
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