Characterization of an Inorganic Powder-Based Scintillation Detector Under a UHDR Electron Beam

Area of Science:

• Medical Physics
• Radiation Oncology
• Detector Physics

Background:

• Ultra-high dose rate (UHDR) radiation therapy requires precise dosimetry.
• Scintillation detectors are being explored as potential dosimetry solutions for UHDR applications.

Purpose of the Study:

• To characterize an inorganic powder-based scintillation detector using ZnS:Ag.
• To evaluate its performance under a 9 MeV UHDR electron beam for dosimetry applications.

Main Methods:

• A ZnS:Ag powder and optic glue mixture was coupled to a polymethyl methacrylate (PMMA) optical fiber.
• Detector response was evaluated against dose per pulse (DPP), pulse repetition frequency (PRF), and pulse width (PW).
• Stability and reproducibility were assessed under repeated irradiations.

Main Results:

• The ZnS:Ag detector exhibited a signal yield 54 times greater than a plastic scintillator.
• Signal variation was minimal (<0.5%) with PRF changes and linear with DPP and PW.
• The detector showed excellent stability (0.83% std dev) and reproducibility (±1.5% daily variation).
• Linear response to integrated dose up to 180 Gy was observed.

Conclusions:

• The ZnS:Ag scintillation detector is suitable for accurate dosimetry in UHDR radiation therapy.
• Its performance characteristics make it a viable option for UHDR beam monitoring.