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 ∼80 mSr with an intrinsic momentum resolution of Δp/p ∼ 10^-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 ¹³²Xe target, then the luminosity and angular distributions were successfully measured at the electron beam energy of 150-300 MeV, achieving a luminosity above 10²⁷cm^-2s^-1. In this article, we present the performances of the WiSES and LMon detectors obtained by using the ¹³²Xe experiment data.