The performance of the SCRIT detectors for electron-RI scattering experiment

The SCRIT (Self-Confining RI Ion Target) facility has been constructed at RIKEN to make the electron-RI scattering experiment possible for the first time in the world. At SCRIT, the angular momentum distribution of scattered electrons is measured by WiSES (Window-frame Spectrometer for Electron Scattering) which consists of a dipole magnet and front/rear drift chambers, covering a solid angle of $\sim$80 mSr with an intrinsic momentum resolution of $\Delta p/p\sim10^{-3}$. Also the luminosity of the electron-RI scattering is estimated from bremsstrahlung photons measured by LMon (Luminosity Monitor) to obtain the absolute cross-section of the scattering. The LMon consists of a CsI calorimeter to measure the photon energy, and plastic fiber scintillators to measure the 2D hit distribution of the bremsstrahlung photons. In 2015-2016 the first physics experiment has been performed using $^{132}\rm Xe$ target, then the luminosity and angular distributions were successfully measured at the electron beam energy of 150-300 MeV, achieving a luminosity above $10^{27}cm^{-2}$s$^{-1}$. In this article, we present the performances of the WiSES and LMon detectors obtained by using the $^{132}\rm Xe$ experiment data.