Beam current calibration for Coulomb sum rule experiment in JLab Hall-A

To obtain the cross section of electron scattering on different cryogenic targets (2H, 4He, 2C, 56Fe, 208Pb) for the Coulomb sum rule (CSR) measurement in JLab Hall-A, the beam current monitor (BCM) was calibrated more reliable than before at different current settings (02, 05, 1, 2, 5, 10, 20, 40, 60 μA) to determine the beam charge precisely at different kinematic settings.