Optical fibers under irradiation: quantitative assessment of the energy distribution of radiation-induced trapped states

Silica-based scintillators: basic properties of radioluminescence kinetics

“…In practise, we use the relative densities of traps H k /H plotted in figure 2 as a function of trapping depths E k . For depths above 0.76 eV, the limit between emptied and stable levels at the beginning of TSL readouts in [40], it is proportionnal to the relative trap populations found for undoped silica in this reference (see inset). We extended this distribution down to 0.46 eV with a kind of exponential tail.…”

“…Several studies concluded that the trapping cross-section is much smaller than the recombination cross-section for holes (β/γ ≪ 1), by at least three orders of magnitude [21,22,40]. Free electron transport is almost not affected by disorder in silica so the electron thermal velocity v e should be about 10 7 cm s −1 , as usual [41].…”

“…Activation energies (trapping depths) of trapped-hole states in silica glasses samples containing various dopants, including RE ions, have been investigated by thermally stimulated luminescence (TSL) in [40]. In this work, a theoretical procedure was proposed to extract at once the PEFs β k N v , activation energies E k , and the relative trap population densities h k existing at the beginning of the TSL readout from TSL curves measured at several heating rates.…”

“…Indeed, when a TSL readout is started at a time t 1 after irradiation, it only probes populations on levels that have not been emptied before t 1 . With a unique trapping coefficient β, we can thus consider that densities of traps H k are simply proportionnal to the relative trap populations estimated from TSL in [40].…”

“…When a single trapping coefficient β is considered instead of M distinct β k values, the number of unknown parameters is then reduced from 3M + 3 to 5 (β, δ, γ, H and N V ). The PEF estimated in [40] varies from 10 9 to 10 10 s −1 for the five investigated silica samples. If we retain βN v = 5 × 10 9 s −1 , only four unknowns remain (β or N V , δ, γ and H) for which physically plausible orders of magnitude can be given.…”