Cross-facility absolute charge calibration of scintillating screens for laser wakefield accelerated beam diagnostics

Scintillation screens are widely used to diagnose high-charge density, low-average current electron beams from laser wakefield accelerators (LWFAs). However, the absolute response between emitted photons and electron charge has only been calibrated at a limited number of facilities, and there have been discrepancies between these calibrations. In this report, we comprehensively revised the absolute charge calibration of two high relative brightness scintillating screens of LANEX Regular (Carestream) and PI200 (Mitsubishi) by employing the high-brightness photoinjector at the National Synchrotron Radiation Research Center (NSRRC), which provides electron beams with variable charges (50-350 pC per pulse) and energies (26.55, 34.50, 42.10 MeV). Our results show that the energy-independent fluorescence efficiency of LANEX Regular and PI200 is (7.39 ± 0.38) × 109 and (2.04 ± 0.04) × 1010 photons/sr/pC, respectively, and both screens retained over 98.5% efficiency at accumulated charge densities up to 500 nC/mm2. These results provide a robust framework for applying the scintillation screens in LWFA diagnostics to enhance accuracy and reliability in electron beam characterization.