Pion dosimetry with thermoluminescent materials

Area of Science:

• Medical Physics
• Radiation Dosimetry
• Particle Physics

Background:

• Accurate dosimetry is crucial for particle therapy, particularly for high linear energy transfer (LET) radiation like pi-mesons.
• Thermoluminescence (TL) offers a promising method for measuring absorbed doses in various materials.
• Evaluating different thermoluminescent materials is essential to find optimal detectors for specific radiation types.

Purpose of the Study:

• To investigate the suitability of various thermoluminescent materials for pi-meson dosimetry.
• To assess the linearity, reproducibility, and sensitivity of selected materials under pi-meson irradiation.
• To determine if different TL peaks can provide information about the high LET component of the radiation.

Main Methods:

• Irradiation of thermoluminescent materials (6LiF, 7LiF, Li2B4O7:Mn, CaSO4:Dy, CaF2:Mn, CaF2-Dy, CaF2:Tm) with a 176 MeV/c pi-meson beam.
• Dose range from 0.05 to 2 Gy applied across the depth dose distribution.
• Analysis of low- and high-temperature TL peaks for LiF, CaF2:Dy, and CaF2:Tm, focusing on integral TL signal and peak height ratios.

Main Results:

• CaF2:Tm demonstrated the highest suitability for pi-meson dosimetry, enabling determination of total dose and high LET component via integral TL and peak height ratios (150°C/240°C).
• Both low- and high-temperature peaks in CaF2:Tm showed linear dose response within the tested range (0.05-2 Gy).
• CaF2:Tm exhibited a sensitivity approximately 10 times higher than LiF, with a reproducibility of +/- 3%.

Conclusions:

• CaF2:Tm is a highly sensitive and reproducible thermoluminescent material for pi-meson dosimetry.
• The analysis of TL peak characteristics in CaF2:Tm allows for the differentiation of dose and LET information.
• Other materials like 7LiF and CaF2:Dy were found less suitable due to issues with high-temperature peak accuracy or LET-dependent response.