New Design of Scintillation Strips for the DANSS Detector Upgrade

Scintillation plastic strips with wave length shifting fibers are the basic elements of the sensitive volume of the reactor antineutrino detector DANSS. The need for the strip’s design improvement is caused by the limitations of the experiment sensitivity to the sterile neutrino searches due to the moderate energy resolution of the detector. The new design of the strips features much higher light output and better light collection homogeneity. A method is discussed of simultaneous light detection from both ends of each fiber. This doubles the number of detected photons and gives information on the longitudinal event coordinate. The paper reflects the details and the status of the detector upgrade together with the recent beam test results. The expected influence of the improvements on the sensitivity to the sterile neutrino is also considered.