A new approach to use LYSO scintillators for polarimetry in the storage ring EDM measurements

One of the fundamental questions of modern particle physics is the existence of finite electricdipole moments (EDM) of the hadrons. In case of charged particles, like protons and deuterons,the proposed method is the precise determination of the precession of the beam polarization vec-tor in a storage ring. For that purpose, the JEDI (Jülich Electric Dipole moment Investigations)collaboration is developing a precise polarimeter detector based on LYSO scintillator coupled toSiPM modules. They are capable of stopping almost 300 MeV elastically scattered deuterons andprotons. Measuring the kinetic energy of the scattered projectiles ensures the accurate reactionidentification leading to a precise polarization determination.To create the long-term reliable detector system, we have performed four iterations of the detec-tor development (three of them since last CALOR 2016). Currently, we are operating 52 LYSOmodules with a dedicated dead-time less sampling ADC readout system. The modules are verycompact, due to modern high pixel density SiPM readout. A summary of all test beam times andthe accumulated experience will be presented and discussed