  DANSS is a one cubic meter plastic scintillator detector with a primary goal
of the sterile neutrino searches at a commercial nuclear reactor. Due to its
highly advantageous location, fine segmentation and ability to change the
distance to the neutrino production origin DANSS is ahead of many similar
experiments around the world in terms of the counting rate, signal to
background ratio and sterile neutrino exclusion regions. Yet a moderate energy
resolution of the detector prevents the further progress in the physics
program. The main challenge of the planned upgrade is to achieve the energy
resolution of 12% at 1 MeV. The new design of the main sensitive element - the
plastic scintillation strip - is the most important step forward. 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, longitudinal timing information and other
optimizations will surely help to reach the upgrade goal. The paper discusses
the drawbacks of the current strip version, outlines the new features of the
proposed upgrade, describes the beam test procedure and presents the test
results reflecting the advantages of the new strip design in comparison with
the currently used version.
