The Risø B3 film dosimetry system is used for high-dose measurements and high-resolution dose distribution mapping in radiation processing applications. The system is based on radiochromic B3 dosimeter film in combination with optical readout systems and calibrated reference standards, enabling accurate and traceable dose evaluation.
The B3 dosimeter consists of a polyvinyl butyral film (~18 µm) containing pararosaniline cyanide dye, which changes from transparent to magenta upon irradiation. Following irradiation, the film response is stabilized by controlled heating (typically 60 °C for 5–10 minutes), ensuring long-term stability of the signal and enabling reproducible measurements over extended periods.
Dose evaluation is performed either by spectrophotometric measurement or by flatbed scanning of larger film areas and analyzed using RisøScan software, depending on the application. Scanner-based analysis is supported by reference step tablets, consisting of irradiated B3 film segments. This dosimetry system enables detailed two-dimensional mapping of dose distributions, particularly in complex irradiation geometries.
The dosimetry system supports measurements over a dose range of approximately 1 to 150 kGy and is applicable for gamma rays, X-rays and electron beams. It is widely used for dose mapping, process validation and research, especially in applications where high spatial resolution and analysis of dose gradients are required.
