OSL and thermally assisted OSL response in dental enamel for its possible application in retrospective dosimetry

Abstract

Dental enamel was studied for its thermoluminescence (TL) and optically stimulated luminescence (OSL) defects. The TL studies showed a wide glow curve with multiple peaks. The thermally assisted OSL (TA-OSL) studies showed that the integrated TA-OSL and thus OSL signal increases with readout temperature between 100 and 250 °C, due to the temperature dependence of OSL. The thermally assisted energy E A associated with this increase is found to be 0.21 ± 0.015 eV. On the other hand, the signal intensity decreases with temperature between 260 and 450 °C. This decrease could be due to depletion of OSL active traps or possible thermal quenching. The increase of the OSL signal at increased temperature can be used to enhance the sensitivity of dental enamel for ex vivo measurements in retrospective dosimetry. The emission and excitation spectra of its luminescence centers were studied by photoluminescence and were found to be at 412 and 324 nm, respectively. It was found to possess multiple OSL active traps having closely lying photoionization cross sections characterized by continuous wave OSL and nonlinear OSL methods. The investigated dental enamel samples showed a linear OSL dose response up to 500 Gy. The dose threshold was found to be 100 mGy using a highly sensitive compact OSL reader with blue LED (470 nm) stimulation.

Investigation of properties of electroconducting nanozones in materials of various nature by the electron paramagnetic resonance method

“…Numerous works [3][4][5][6][7][10][11][12][13][14] are dedicated to the study of properties of biominerals (enamel, bones) and organic poly-Методом електронного парамагнітного резонансу вивчені електропровідні області в біомінералах (емаль зубів, кістки), і в полі-амідних полотнах, що містять наночас-тинки поліаніліну. Встановлено, що харак-теристики електронного парамагнітного резонансу електропровідних нанообластей в біомінералах і текстильних матеріалах, що містять наночастинки поліаніліну, є подібними.…”

“…Це обумовлено схожістю пара-магнітних носіїв заряду, локалізованих в нанорозмірних електропровідних областях біомінералів і органічних полімерів [10], however variation of EPR signals under effect of metal ions of various concentrations on properties of human teeth and bones was not taken in account. Work [6] investigated properties of enamel by the method of optically stimulated luminescence (OSL). Intensity of OSL signal decreased with the growth of annealing temperature from 260 tо 450 °C.…”

“…Such studies are of importance in solution of basic problems, for example, elucidation of mechanisms of charge transfer and description of features of internal structure in both minerals of biogenic origin [1,2] and conductive organic polymers [3,4]. Among applied problems, retrospective human dosimetry [5][6][7] and the problems associated with creation of conductive textile materials with the use of conductive polymers [8,9] should be mentioned. Availability of conductive zones in biominerals exerts an essential influence on veracity of the results associated with reconstruction of radiation-absorbed doses a person got in the past.…”

“…Availability of conductive zones in biominerals exerts an essential influence on veracity of the results associated with reconstruction of radiation-absorbed doses a person got in the past. It is due to the fact that conductive zones in biominerals generate signals of electron paramagnetic resonance (EPR) which overlap with the signals used in reconstruction of the human radiation dose [5,6]. Elucidation of connection of the EPR characteristics with the mechanisms of electrical conductance in organic polymers is an urgent problem.…”

Retrospective and emergency dosimetry in response to radiological incidents and nuclear mass-casualty events: A review

“…Soni et al (2014) examined the so-called "thermally assisted" OSL response from dental enamel and, using small samples, were able to maximize the sensitivity by performing the OSL measurement at 250 °C. Clearly this can only be performed with ex vivo samples.…”