Scattered proton detection system for scattering experiment with the cylindrical scintillating fiber tracker and BGO calorimeters

Nakada, Yoshiyuki; Hasegawa, Shoichi   ; Hayakawa, Shuhei

The proton detection system is under construction for the scattering experiment at J-PARC (J-PARC E40) for the purpose of investigating Baryon-Baryon interaction. The E40 experiment is a double-scattering experiment, that is, followed by in the liquid hydrogen () target. Then, the scattering events are identified by tagging the production with spectrometer systems, and by measuring the scattered proton with the proton detection system. The momentum of produced can be calculated from the momenta of and measured by the spectrometer systems. We can reconstruct scattering events using their kinematics. The scattered proton detection system (CATCH: Cylindrical Active Tracker and Calorimeter system for Hyperon scattering) for this experiment is composed of cylindrical scintillating fiber tracker (CFT) and calorimeter of bismuth orthogermanate (BGO) crystals. Enough energy resolution of CFT to separate protons and s is essential for good S/N. The construction of the 2 layer of CFT (CFT-2 and CFT-UV2) was completed. We performed a test experiment at the Cyclotron and Radioisotope Center in Tohoku University to evaluate its performance. proton beams were irradiated to polyethylene () film target, and proton scattering data were acquired. Using the and scattering data, we evaluated proton detection efficiency of CFT-2 and -UV2 and their energy resolution.