PURPOSE: Scintillation dosimetry has promising qualities for ultra-high-dose-rate (UHDR) radiation therapy (RT), but no system has shown compatibility with mean dose rates (DR¯) above 100 Gy/s and doses per pulse (D METHODS AND MATERIALS: We undertook a thorough dosimetric characterization of the system on an UHDR electron beamline. The system's response as a function of dose, DR¯, D RESULTS: Within a tolerance of ±3%, the system exhibited dose linearity and was independent of DR¯ and D CONCLUSIONS: With daily calibrations and DR