Thermoluminescence solid-state nanodosimetry--the peak 5A/5 dosemeter.

Area of Science:

• Solid State Physics
• Radiation Detection and Measurement
• Materials Science

Background:

• LiF:Mg,Ti (TLD-100) is a widely used thermoluminescent dosimeter.
• Composite peak 5 in TLD-100 exhibits complex behavior influenced by pre-irradiation annealing.
• Previous studies highlighted the dependence of peak 5 shape on cooling rates.

Purpose of the Study:

• To investigate the influence of ionization density on the shape of composite peak 5 in LiF:Mg,Ti.
• To determine if peak 5's characteristics can be utilized for measuring average ionization density.
• To assess the potential of the peak 5a/5 ratio as a nanodosimeter.

Main Methods:

• Irradiation of LiF:Mg,Ti samples with varying ionization densities (beta particles, heavy ions, electrons).
• Analysis of glow curves using a computerized deconvolution code based on first-order kinetics.
• Determination of kinetic parameters for peaks 4 and 5 from ancillary measurements.
• Measurement of the peak 5a/5 intensity ratio under different irradiation conditions.

Main Results:

• The shape of composite peak 5 is dependent on ionization density, independent of cooling rate.
• High-ionization density irradiation leads to a decrease in peak 5 temperature and broadening, attributed to increased peak 5a intensity.
• The peak 5a/5 ratio increases with increasing ionization density, from 0.13 for low-ionization density to ~0.8 for high-ionization density.
• Slow-cooled samples offer higher precision in measuring the 5a/5 ratio (~15% vs ~25%).

Conclusions:

• The ionization density dependence of composite peak 5 in LiF:Mg,Ti is confirmed.
• The peak 5a/5 ratio serves as a viable indicator of average ionization density at a nanoscopic level.
• This finding supports the development of a peak 5a/5 nanodosimeter for radiation dosimetry applications.