TL response of LiF : Mg,Ti exposed to intermediate energy¹H,³He,¹²C,¹⁶O and²⁰Ne ions

Abstract

The dependence of the thermoluminescent (TL) LiF : Mg,Ti response as a function of linear energy transfer (LET) has been investigated, through a careful analysis of the induced glow curve. We have irradiated TLD-100 chips in a stack with low fluences (5 × 105–5 × 107 cm−2) of a variety of ions: 1, 3, 25 and 40 MeV µ−1 hydrogen, 25 and 40 MeV µ−1 helium, 15, 25 and 40 MeV µ−1 carbon, 25 MeV µ−1 oxygen and 40 MeV µ−1 neon, spanning a LET interval from 1.55 to 517 keV μ m−1. For all peaks, except peak 8, the measured TL response is a linear function of deposited energy. We have observed differences between the LET dependence of the low- (4 and 5) and the high- (6a to 9) temperature peaks: the low-temperature peaks decrease their presence in the glow curve as LET increases, while the high-temperature peaks do the opposite. The peak 8 response exhibits linear–supralinear behaviour as a function of dose, the strongest LET dependence and the highest efficiency relative to gamma rays (about 20 near 200 keV μ m−1). The observed evidence of the glow curve shape evolution with LET and the response to gamma rays suggests that the entities responsible for the LiF : Mg,Ti high- and low-temperature peaks have widely different properties.

Use of Thermoluminescence Dosimetry for QA in High-Dose-Rate Skin Surface Brachytherapy with Custom-Flap Applicator

“…The reader is equipped with pure (99.995%) nitrogen supply needed to suppress chemiluminescence and spurious signals not related to irradiations. Readout was performed after a 10 s pre-heating to 100 • C by integrating the thermoluminescent signal up to 300 • C with a linear heating rate of 5 • C/s (40 s total integration time) chosen to optimize the signal-to-background ratio [48]. Measurements were obtained by integrating the signal in the region 150-250 • C, where the main peak is (at 195 • C), obtaining the reading R.…”

Sensitivity correction of fluorescent nuclear track detectors using alpha particles: Determining LET spectra of light ions with enhanced accuracy

“…Therefore, being able to calculate or measure the LET could be advantageous or necessary to predict the RBE on clinical scenarios. Knowledge regarding the LET may also be essential for accurate dosimetry in PT and IBT, as the responses of several dosimeters exhibit dependence with the LET 5–9 . For beams commonly used in PT and IBT, the LET increases with penetration depth, but most notably at the distal end, as a result of the slowing down of the ions; thus a single LET value is not sufficient to globally describe the radiation field, and local values are more suitable.…”