Modelling the absorbed dose rate of the beta standard BSS2 ¹⁴⁷Pm source

Area of Science:

• Medical Physics
• Radiation Dosimetry
• Nuclear Engineering

Background:

• Low-energy beta emitters like Promethium-147 (¹⁴⁷Pm) present dosimetric measurement challenges due to dispersion and attenuation.
• Accurate absorbed dose rate determination is crucial for applications involving ¹⁴⁷Pm sources.

Purpose of the Study:

• To develop and validate a Monte Carlo model for determining the absorbed dose rate of ¹⁴⁷Pm beta radiation.
• To compare simulation results with experimental measurements and a calibration certificate.

Main Methods:

• Development of a Monte Carlo model incorporating an extrapolation chamber and a ¹⁴⁷Pm source.
• Experimental determination of the absorbed dose rate using established methods.
• Utilizing the MCNP Monte Carlo code for simulation.
• Analysis of particle transport through source and chamber windows, and determination of the source fluence spectrum.

Main Results:

• The Monte Carlo model successfully simulated particle transport and determined the source fluence spectrum.
• Experimental measurements and Monte Carlo simulations showed strong agreement with each other.
• Both simulation and experimental results closely matched the absorbed dose rate provided by the PTB calibration certificate, with a difference of only 0.8%.

Conclusions:

• The developed Monte Carlo model provides a reliable method for ¹⁴⁷Pm absorbed dose rate determination.
• The study validates the accuracy of the Monte Carlo approach for low-energy beta dosimetry.
• The findings confirm the suitability of the model for applications requiring precise dosimetry of ¹⁴⁷Pm sources.