Kinetic modeling of Fluorine vacancy/F center creation in LiF:Mg,Ti including vacancy-interstitial recombination: Evaluating the factors leading to the lack of supralinearity in the optical absorption F center concentration dose response

Probing the defect nanostructure of helium and proton tracks in LiF:Mg,Ti using optical absorption: Implications to track structure theory calculations of heavy charged particle relative efficiency

“…4 and 5 respectively. The intensity of the 4.0 eV band following HCP irradiation is very low compared to the LID induced intensity [43]. The 5.45 eV OA band was not observed at low fluence so its relative OA efficiency could not be measured.…”

“…The higher value per MeV for the protons is probably due to greater frequency of vacancy-interstitial recombination and defect agglomeration in the He track due to the higher levels of radial dose. Eliyahu et al [43] have estimated that following uniform irradiation vacancy-interstitial recombination occurs for critical distances, d c , less than $40 Å. Similar values of d c in the HCP tracks would strongly limit F center production in the track cores.…”

“…In any event the value of f does not impact the experimental measurement of g unless its value is somehow altered in the environment of the HCP track. For the other OA bands in the LiF OA spectrum no data/information is available so that only the value of NÁf was estimated by Eliyahu et al [43] as shown in Table 1.…”

“…The major OA bands are at 5.08 eV (F center), 4 eV (associated with the trapping center of composite glow peak 5), 4.77 eV (unknown structure-sometimes suggested as F centerrelated [44]) and 5.45 eV (believed to be a competitive center in the heating/recombination stage giving rise to TL glow peak 5) [45]. The maximum F center concentration, N Fmax , at saturation following LID irradiation is $6 Â 10 23 m À3 using f = 0.82 [43]. Following HCP irradiation of single crystal LiF N Fmax is significantly greater.…”

“…The Ben Gurion University (BGU) group has measured the OA of LiF:Mg,Ti samples over an extended dose-range from 10 Gy to 10 5 Gy. The dose response of the absorbance, a, of all the major bands are linear/exponentially saturating [43,55] with…”