  In this study, we developed a new proton detector system called CATCH, which
was designed for a scattering experiment involving a $\Sigma$ hyperon and a
proton (J-PARC E40). CATCH is a cylindrical detector system covering an inner
target that can be used to measure the trajectory and energy of a proton
emitted from the target for the kinematic identification of a $\Sigma$p
scattering event. It comprises a cylindrical fiber tracker (CFT), a bismuth
germanate (BGO) calorimeter, and a plastic scintillator hodoscope (PiID), which
are coaxially arranged from the inner to the outer sides. The CFT is a tracking
detector consisting of 5,000 scintillation fibers, and it has two types of
cylindrical layers in which the fibers are arranged in straight and spiral
configurations. 24 BGO crystals are placed around the CFT to measure the
kinetic energy of the recoil proton. The PiID is used to determine whether the
recoil proton is stopped in the BGO calorimeter. We performed proton-proton
(pp) and proton-carbon (pC) scattering experiments using an 80 MeV proton beam
to evaluate the performance of CATCH. The total energy resolution for the
recoil proton was 2.8 MeV in $\sigma$ for the entire angular region after the
energy calibrations of the BGO calorimeter and the CFT. The angular resolution
of the CFT was 1.27 degrees in $\sigma$ for the proton, and the time resolution
was more than 1.8 ns in $\sigma$. We also developed an analysis method for
deriving the cross section of the pp scattering using CATCH. The obtained
relative differential cross section for the pp elastic scattering was
consistent with that obtained by reliable partial wave analysis, and the
systematic error was maintained at below 10%. These performance results satisfy
our requirements for a reliable detection system for the $\Sigma$p scattering
experiment conducted at J-PARC .
