Heavy charged particle thermoluminescence dosimetry: Track structure theory and experiments

Alpha particle and proton relative thermoluminescence efficiencies in LiF:Mg,Cu,P:is track structure theory up to the task?

“…The systematics of the decreasing relative HCP TL efficiency with LET was described more than three decades ago (14) along with microdosimetric calculations based on modified TST (15) . In these early studies, D(r) for low-energy alpha particles stopping in LiF was calculated using scaling techniques, which were used to extrapolate from Monte Carlo calculations in gas and f (D) was measured experimentally in both nitrogen and air-annealed samples with 60 Co gamma rays, 50 kV p and 20 kV p X rays as well as 3 H beta rays.…”

“…f(D) max 3-5 for 60 Co gamma rays decreasing to 1.8 for 20 kV p X rays ( Figure 7). This dependence of f(D) on photon energy is attributed to the competition between localised and de-localised recombination in the UNIM (4,29) and motivated the development of modified TST (MTST) (14,15) in which it is required that f (D) be measured with photon or electron energies that create a secondary electron energy spectrum approximately matched to the HCP-generated electron spectrum.…”

“…R max and r max are the maximum axial and radial distances of penetration of the charge carriers from the HCP path (in the radiation absorption stage); f d (D) is the TL dose-response measured with a test electron radiation chosen to mimic the radiation action of the HCP as closely as possible. Further information is available in other publications (4,14,15,33) . Due to the great variability of even relative quantities in TL characteristics, it is necessary to emphasise the importance of measuring f d (D) under experimental conditions and protocol identical to the experimental measurement of h HCP,g (34,35) .…”

Dosimetry experiments at the MEDUSA Facility (Little Mountain).

“…The response of CaF 2 :Mn is known to be reduced for high LET particles, 11 as shown in the following summary.…”

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

“…It deserves mention that although the ratio of the intensity of peak 5a to peak 5 increases, the overall relative TL efficiency of composite peak 5 (normalised to LID radiation) decreases owing to full population of the available TCs and LCs in the high-dose regions in the track where the radial dose is greater than 1000 Gy). Two competing effects of ionisation density are thus at play: increased geminate/localised recombination ( peak 5a) owing to an increase in the relative number of e-h occupied TC/LC pairs and decreased TL efficiency owing to full occupation of the TCs and LCs leading to dose 'wastage' (23) . The value of the 5a/5 ratio for the very heavy ions (Cu and I) is somewhat lower than expected and may indicate the role of defect production owing to enhanced nuclear scattering in the efficiency of the luminescence mechanisms (3) .…”