Thermoluminescence Glow Peak Research Articles

Blue- and infrared-light stimulated luminescence of microcline and the effect of optical bleaching on its thermoluminescence

We report blue-light stimulated luminescence (BSL) and infrared-light stimulated luminescence (IRSL) of microcline along with the effect of optical bleaching on its thermoluminescence (TL) glow peaks. Analysis of BSL and IRSL decay curves of the sample shows that the decay curves are composed of a fast component C1 and a slow component C2. The decay time of these components depends somewhat on dose. For components C1 and C2 of BSL, the decay times are consistent at (3.47 ± 0.31) s and (27.19 ± 1.39) s respectively for doses within 1–10 Gy but become faster for dose beyond 10 Gy. On the other hand, the decay times of the component C1 of IRSL for any doses between 1 Gy and 100 Gy are consistent at (8.61 ± 2.10) s and that of C2 at (44.97 ± 6.43) s. The difference in decay times between BSL and IRSL emission are attributed to nature of transitions involved in BSL and IRSL emissions. Analysis of BSL and IRSL dose responses shows that the BSL decay curves as well as its components C1 and C2, each produce a linear response within 1 Gy–10 Gy and increases exponential thereafter. In comparison, the dose response of the IRSL as well as that of its components are linear between 1 Gy and 100 Gy. Studies comparing the effect of optical bleaching on the TL intensity suggests that use of infrared light for this purpose can produce a relatively longer linear dose response than that following bleaching by blue light.

Revealing the theoretical assumptions of the trap-depth distribution model in the thermoluminescence theory

The theoretical assumptions of the analytical expressions characterizing the thermoluminescence glow-peak arising from a continuous trap-depth distribution have been investigated. The sets of the differential equations governing the electrons’ transitions within a continuous trap-depth distribution during the irradiation and heating stages have been numerically solved. The analytical expressions are essentially based on a theoretical assumption that correlates the concentrations of the trapped electrons with the distribution of the trap depths in the bandgap. This correlation could not be considered in the numerical solution, since the irradiation stage is entirely independent of the trap depth. Thus, the final values of the instantaneous trap-filling functions of the irradiation stage do not depend on the trap depth, but rather on the trap capacity and the trapping probability coefficient. Consequently, in the numerical solution, the distribution of the trap depths and the distribution of the trapped electrons are independent. This inconsistency between the numerical solution and the analytical expression has led to differences in the shape of the thermoluminescence glow peaks resulting from the same trap-depth spectrum.

Dosimetric behavior of modified borate bioglass containing copper for low photon dose measurements using luminescence characteristics

Presented work deliberate the dosimetric impact of low absorbed dose in modified borate bioactive glass as utilization for such newly studied material. The particle size impact, glow curve, relative response to different doses, and dose fading impact was examined as thermoluminescence (TL) properties moreover. Thermoluminescence investigations of borate bioglass containing copper oxide irradiated by γ-ray demonstrated a conspicuous TL glow peak maximum at 353 °C. The TL emission peak due to defects identified with the host material. The outcoming results are concerned with their uses in low dose dosimetry. The outcoming showed that the ideal grain size is extended between 53 and 106 µm.), respecting to glow peak of borate bioactive glass after gamma irradiation from gamma radiation cobalt source, three unresolved glow peaks was founded. The linear relationship response curve in the portion runs from 0.1 up to 1.5 Gy. The absolute TL-signal seems to be constant through 30 days of storage of the modified samples. Peaks activation energies were calculated through TL kinetics in deep traps, which recommended store the TL-signal. The low detected with a threshold value (0.01 Gy) fusing with this strategy represented as a good radiation sensitivity making it permissible to use for individual accidental retrospective. However, in the case of a personal dosimeter, Good and helpful data can be gotten on. Treatment would then be able to be founded on this data moreover.

Influence of scatter data and temperature lag on the analysis of thermoluminescence glow peak: A Monte Carlo simulation study

The effects of the scattering data that might appear at the low radiation doses and the temperature lag that might occur between the heater pan and the detector on the thermoluminescence (TL) glow-curve have been addressed. The scattering data were mathematically induced in the TL glow curve using the Monte Carlo (MC) algorithm. While the phenomenon of the temperature lag has been simulated, assuming an exponential function. The deconvolution analysis has been carried out by TL expressions based on a presumed kinetics order value in comparison with the general-order kinetics equation. It has been found that even though the glow peak is known to obey the first- or second-order kinetics model, using the general-order kinetics equation in the deconvolution analysis is better than using the corresponding model equation.

Structural and optical properties of beta irradiated YAlO3 single crystals

We report on the growth, structural and optical properties of YAlO3 single crystals grown by optical floating zone technique. Powder X-ray diffraction and Raman spectroscopic studies confirm the phase purity of the crystals. Raman analysis reveals that the intensity and line-width of Raman bands increase significantly with beta irradiation indicating the formation of structural defects in YAlO3 lattice. The optical properties are studied through UV–visible absorption, and photoluminescence emission and excitation spectroscopies under pre- and post- beta irradiation. The optical studies indicate the presence of Sm and Cr impurities by exhibiting characteristic emission lines in the orange red region. Further, a systematic study on the thermoluminescence (TL) characteristics of the crystal is also carried out at different doses of beta irradiation. The crystals exhibit a prominent TL glow peak at 239 °C for less than 5 Gy doses while a weak second glow peak evolves at higher doses. Also, the crystals show a nearly linear dose response in the studied range from 0.1 to 10 Gy. The glow curve analysis reveals that the TL emission obeys the first order kinetics model. Based on the optical studies, the plausible mechanism for the TL glow curve is discussed in terms of the intrinsic defects and impurities that are present in the crystal.

Thermoluminescence based personnel neutron dosimetry study of LiMgBO3:Dy3+

The present paper reports the thermoluminescence (TL) based personnel neutron dosimetry studies of LiMgBO3: Dy3+ phosphor. It offers the great advantage of being a near tissue equivalent material with Zeff = 9.1. Also, the presence of both Li and B in the host matrix directly induce TL signal for neutrons. This is highly advantageous over CaSO4: Dy based TL neutron dosimeters where it requires to mix some thermal neutron sensitive species with the host matrix to induce neutron response. LiMgBO3: Dy3+ was synthesized by sol gel method and its structural characterizations were done by XRD, SEM and EDS techniques. TL upon irradiation with neutrons showed the glow peak at ~140 °C (413K). TL response up to 200 mSv of neutron dose showed very good linearity with adj. R2 = 0.998. 30% borated rubber discs were successfully utilised for the segregation of the gamma dose from the total dose in the mixed field (neutron + gamma) environments. The minimum detectable dose of the material was found to be 27.5 μGy and 2.7 μSv for gamma and thermal neutrons respectively. The TL sensitivity of LiMgBO3: Dy3+ for neutron and gamma radiation is 0.6 times and 0.3 times respectively with respect to that of standard TLD-100 [LiF: Mg, Ti] material. The proposed LiMgBO3:Dy3+ was also found to have better n/γ dose discrimination capability as compared to the commercially available TLD-100 material [LiF: Mg, Ti]. The kinetic parameters (viz. E, b and s) of the neutron irradiated TL glow peak were determined by Chen's peak shape and by variable heating rate methods.

Detailed luminescence (RL, PL, CL, TL) behaviors of Tb3+ and Dy3+ doped LiMgPO4 synthesized by sol-gel method

The un-doped, Tb3+ and, Dy3+ doped LiMgPO4 phosphors were successfully synthesized by the sol-gel method. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were employed to characterize the light-emitting phosphors. The XRD spectra verify the phase formation of samples. The luminescence properties were analyzed by radioluminescence (RL), photoluminescence (PL), cathodoluminescence (CL) and, thermoluminescence (TL) spectra. Also, the effect of Tb3+, Dy3+ ions in LiMgPO4 was determined on the luminescence intensity in detail.The RL spectrum of un-doped LiMgPO4 consists of two broad emission bands in the 310–450 nm and 575–850 nm range. The maximum intensities of these bands were observed at 360 nm and 655 nm. The emission spectrum of Dy3+ doped LiMgPO4 under X-ray excitation show characteristic emissions of Dy3+ corresponds to 4F9/2→6Hj transitions. In addition to the 5D4→7Fj (j:6–1) transitions of Tb3+ doped LiMgPO4 phosphor, strong emissions derived from 5D3→7Fj (j:6–3) transitions were observed in the blue region. Also, these blue emissions were seen at RL, PL and, CL spectra. The optical absorption spectra were recorded and the energy band gaps were calculated 3.62 eV, 3.30 eV and, 4,01 eV for un-doped, Dy3+ and, Tb3+ doped LiMgPO4 phosphors, respectively. The phosphors irradiated with UV (254 nm) light. The main TL glow peak was observed at 288 °C for the Dy3+ doped phosphor, and the peaks at 198, 283 °C were observed for the Tb3+ doped phosphor.

Thermoluminescence characterization of nanocrystalline powder of SrSO4:Sm exposed to gamma radiation for dosimetric applications

Dosimetry properties of nanocrystalline SrSO4:Sm powders prepared via a co-participation method, were studied. X-ray diffraction, energy dispersive X-ray spectroscopy and Field emission scanning electron microscopy (FE-SEM) were used to investigate the structure, composition and morphology of nanocrystalline SrSO4:Sm powders. The nanocrystalline SrSO4:Sm powders had the orthorhombic crystal structure. FE-SEM image showed polygonal structure of particles with an average size of particles 0.2 μm. The thermoluminescence (TL) measurements for different concentration of samarium were done after gamma irradiation. TL glow curves showed the main glow peak at 370 °C. The maximum intensity of the TL glow curves for SrSO4:Sm was obtained with 0.05mol% concentration of Sm. Then, due to its high intensity glow curve, it was selected as the main sample. Furthermore, its dose-response, energy-response, and fading were studied in detail. Nanocrystalline SrSO4:Sm(0.05 mol%) powder had a linear dose-response approximately between 10Gy and 3 kGy. It showed energy dependence for low energy photons and its fading was less than 20% after 37 days. The X-ray excited luminescence (XEL), and TL were examined. The kinetic parameters were calculated by using the various TL analysis methods and OriginPro 8 software. The results showed the main TL glow peak obeyed second order kinetics.

Determination of Thermoluminescence Kinetic Parameters of La2O3 Doped with Dy3+ and Eu3.

Thermoluminescence (TL) properties of La2O3: Dy3+, Li+, and La2O3: Eu3+, Li+, exposed to 5.12 Gy of beta radiation, and recorded at different heating rates 0.5, 1, 2, 3, 4, and 5 °C s−1 (from Molefe et al., paper 2019), were analyzed and the trap parameters were determined in this study. These parameters include the order of kinetics b, the activation energy E (eV), the frequency factor S (s−1), or the pre-exponential factor S″ (s−1), and the initial concentration of trapped electrons no (cm−3). A new non-linear curve fitting technique, based on the general order kinetic equation and the outcomes of Hoogenstraaten’s Method, was established and applied on the TL glow peaks of La2O3: Dy3+, Li+. The fitting technique was evaluated by calculating the R-square and figure of merit (FOM) values. The results revealed that the FOM values are <1%, and the R-square values are >0.997, which demonstrates an excellent convergence between experimental and fitted curves. A modified technique based on the three-points analysis method was exploited to deconvolute complex TL glow curves of La2O3: Eu3+, Li+, and in turn, to determine the trap parameters the method disclosed that each TL glow curve consists of four peaks. The trap parameters of the individual peaks were numerically determined. The fading, as a function of storage temperature and time, from the TL signals of the investigated materials was predicted and discussed based on the calculated trap parameters. The results support the value of the materials for employment in radiation dosimeter applications with a low fading fraction.

TL/OSL response of carbon ion beam irradiated NaMgF3:Tb

Fluoroperovskites are an important class of thermoluminescence (TL)/optically stimulated luminescence (OSL) materials known for their high sensitivity and other good characteristics particularly when doped with a suitable impurity. Fluoroperovskites have not yet been explored for heavy charged particle irradiation like carbon which is commonly used for cancer treatment. In the current work, TL and OSL properties of 85 MeV carbon ion beam irradiated NaMgF3:Tb samples have been investigated in detail at different fluences. Undoped and Tb3+ (0.5 mol%) doped NaMgF3 samples have been synthesized by the melting method. The formation of the material is confirmed using the XRD technique. The crystallite size of undoped and Tb3+ doped NaMgF3 samples are estimated to be 100 nm and 89 nm respectively. TL studies reveal that undoped NaMgF3 shows a well-isolated TL glow peak centered at 412 K while Tb3+ doped NaMgF3 shows more intense TL glow peak at 416 K with a small shoulder peak at 481 K along with a new peak at 647 K. Further, TL glow curves have been analyzed for 85 MeV carbon ion irradiated samples of NaMgF3 for low fluences (1 × 105–1 × 107 ions/cm2) and high fluences (2 × 109–5 × 1012 ions/cm2) to study the dose-response. CW-OSL decay curves of 85 MeV carbon ion irradiated undoped and Tb3+ doped NaMgF3 samples show high OSL intensity under blue light stimulation. The OSL dose-response has been recorded at high (1 × 108–1 × 1010 ions/cm2) and low (1 × 105–1 × 107 ions/cm2) fluences. Linear TL and OSL behaviour in the range 1 × 105–5 × 106 ions/cm2 has been observed. Also, other properties like batch homogeneity and fading studies have been carried out. The related TL/OSL kinetic parameters were determined. Analysis of TL/OSL properties of NaMgF3:Tb suggests that it exhibits appropriate properties for carbon ion beam dosimetry for its utilization in medical applications.

The effect of Dy3+ doping on the thermoluminescence properties of Ba2SiO4

AbstractThe thermoluminescence (TL) properties of barium silicate phosphor, Ba2SiO4:%3Dy3+ synthesized by using hydrothermal method were investigated and presented in detail. The crystallographic structure of Ba2SiO4:%3Dy3+ was determined by conventional x‐ray diffraction technique and the results showed that the sample was grown in orthorhombic phase with Pmcn (62) space group (PDF: 01‐077‐0150). The excitation spectra of Ba2SiO4:Dy3+ were measured in the wavelength range of 220‐400 nm and the spectra showed that there were several excitation bands in the sample. The CIE chromaticity coordinates were also calculated from emission spectra for Dy3+‐doped Ba2SiO4. In order to calculate the kinetic parameters of the sample the additive dose, peak shape and computerized glow curve deconvolution methods were used. It was found that Ba2SiO4:Dy3+ was composed of five general order TL glow peaks. The fading characteristics of the sample were also studied over a period time. At the end of the planned storage times, the normalized TL peak area of Ba2SiO4:Dy3+ reduced 60% of its original value.

The Effect of Cr3+ and Mg2+ Impurities on Thermoluminescence and Deep Traps in β-Ga2O3 Crystals

Thermally stimulated luminescence (TSL) of β-Ga2O3 single crystals doped with Cr3+ and Mg2+ impurities was investigated. Based on the correlation between the Cr3+ concentration and light sum accumulated in the thermoluminescence (TL) glow peak at 285 K, it was concluded that doping of β-Ga2O3 with Cr3+ ions leads to the formation of electron traps manifested in this peak. The activation energy of peak at 285 K is equal to Ec-0.55 eV and close to E1. Thus the Cr3+e− centers can be a candidate for E1. The high-temperature TL glow peak at 385 K (Ec-0.94 eV) is related to oxygen vacancies which are created in gallium oxide doped by Mg2+ ions to compensate for the negative charge formed by the substitution of gallium sites by magnesium ions.The co-doping of β-Ga2O3 crystals with Cr3+ and Mg2+ impurities leads to the appearance of a new TL glow peak at 320 K with an energy close to E*2 (Ec-0.7). It is suggested that this peak is formed by defect complex, in particular, oxygen vacancies with Cr3+ or Fe3+ ions.

Investigating thermoluminescence properties of Na14Al12Si13O51:Dy3+ phosphor for oxygen ion beam exposure

The Na14Al12Si13O51: Dy3+ phosphor is synthesized by combustion method and prepared sample was characterized by X-ray Diffraction, SEM, FT-IR and Thermoluminescence (TL) techniques. TL characteristics show the quenching at 3 mol% of Dy3+ ion activated Na14Al12Si13O51: Dy3+ phosphor with single TL glow peak 154 °C at higher temperature. Prepared phosphor material was irradiated oxygen ion beam at different fluences range from 5 × 1010 to 1 × 1014 ions/cm2. Chens peak method and computerized glow curve deconvolutation method was used to evaluate the trapping parameters namely, activation energy, frequency factor, kinetic order associated with the main glow curve in Na14Al12Si13O51: Dy3+ phosphor after irradiation..

UVC dosimetry properties of Mn and Ce doped KCl thermoluminescent phosphor produced by co-precipitation method

Potassium chloride microcrystalline doped with Mn and Ce was successfully synthesized for the first time by the co-precipitation method and its thermoluminescence (TL) UVC dosimetry properties were investigated. The highest TL sensitivity was achieved at 0.3 and 0.5 mol% of Mn and Ce impurities respectively. The optimum annealing regime was found at 673 K for 15 min. The TL response is linear for illumination with UVC lamp up to 500 s. The optical band gap of 4.16 and 4.34 eV was obtained accordingly for the synthesized Mn and Ce doped KCl phosphor using the absorption spectrum. Tm-Tstop and computerized glow curve deconvolution procedures were used to identify the component TL glow peaks and kinetic parameters of the produced phosphor. Desired dosimetric features, besides the simple glow curve structure and separated glow peaks of the synthesized phosphors, presents them as good candidates for UVC dosimetry.

NUV light-induced visible green emissions of Erbium-doped hierarchical Bi2Zr2O7 structures

We reported a facile strategy to synthesis of Er3+ doped Bi2Zr2O7 nanophosphors via hydrothermal route using Aloe Vera gel as a bio - surfactant. The photoluminescence spectra exhibit intense peaks centered at ~524, 547 and 660 nm, which were attributed to 2H11/2 → 4I15/2, 4S3/2 → 4I15/2 and 4F9/2 → 4I15/2 transitions of Er3+ ions, respectively. The highest photoluminescence intensity was achieved in 5 mol % of Er3+ ions. The electric dipole-quadrupole (d-q) interaction was responsible for the concentration quenching. The fluorescence intensity ratio technique was utilized for optical thermometric properties of the nanophosphors in the temperature range of 303–463 K. At lower temperature (282 K) the relative sensor sensitivity of the optimized nanophosphor was found to be ~0.0621 K−1. Thermoluminescence glow curves of 5 mol % Er3+ ions doped nanophosphor irradiated with γ-rays showed two peaks at ~120 and 203 °C. A thermoluminescence glow peak at ~120 °C showed good linearity with dose, simple glow curve structure, minimal fading and good reproducibility. The above results clearly showed that the optimized nanophosphor is quite useful in WLED's, TL dosimetry and optical thermometry applications.

Thermoluminescence studies of Dy3+-doped calcium barium orthosilicate codoped with Li+ ion

Calcium barium orthosilicate (CaBaSiO4) phosphors having different concentrations of Dy3+ were prepared by solid-state reaction method, and phase structure of the sample was identified by X-ray diffraction (XRD) characterization. It is observed that the XRD pattern matched well with JCPDS file No. 48-0210. Thermoluminescence (TL) of the UV-irradiated (254 nm) samples was recorded using routine TL set-up Nucleonix TLD reader with constant heating rate 5 °C s−1. It is found that the sample containing 1 mol% of Dy3+ and exposed for 27 min gives optimum TL intensity at 130.14 °C and shows single TL glow peak. It order to examine the effect of charge compensator ion, Li+ ions are introduced and it is found the incorporation of charge compensator enhances the TL output. Samples having 1 mol% of Dy3+ and 6 mol% of Li+ exposed for 30 min to UV exposure show maximum intensity at 118 °C. It is also observed that temperature corresponding to TL peak varies with varying Li concentration (ranging from 105.76 to 123.88 °C). Samples having 1 mol% of Dy3+ and 6 mol% of Li+ exposed for 30 min to UV exposure were selected for further studies, such as activation energy, order of kinetics and frequency factor, and all these parameters were evaluated using peak shape method.

Study on Luminescence of KCl:Eu2+ Crystals after X-ray Irradiation at Room Temperature

Bleaching with the F-light at the excitation bandpass of 20 nm results in the phenomenon that F-centre peak and thermoluminescence (TL) glow peaks due to Fz- and F-centres identically decrease with the F-bleach time, whereas TL glow peak due to Fz-centre only remains almost constant irrespective of its time in the case of that at the excitation bandpass of 5 nm. Analysing the data on bleaching effects, absorption spectrum of X-ray irradiated KCl:Eu2+ crystal has a peak due to Fz-centre approximately within 20 nm of the wavelength 560 nm at F-centre peak. Electrons released from Fz-centres at 370 K and from F-centres at 450 K combine with Eu3+ ions, leading to the excited Eu2+ ions from which the luminescence at 420 nm is emitted.

New handling of thermoluminescence glow curve deconvolution expressions for different kinetic orders based on OTOR model

The exact equations of the thermoluminescence (TL) glow curve deconvolution that describe the intensity of a single TL glow peak of different order kinetics, which are obtained from the one trap-one recombination (OTOR) level model, are considered. The reformulation of the expressions of the intensities of TL glow peaks in terms of the peak intensity IM, peak position TM, and the activation energy ∈, for each order of kinetics are achieved. The authors developed a MATLAB computer code, which utilizes the obtained equations, to computationally deconvolute the TL glow curves. The code is used to investigate the reference glow curves of the GLOCANIN program. The obtained results agree with those previously reported by the GLOCANIN project with better values of the figure of merits FOM. The considerations of the obtained equations show promising trends to understand a peak formation for different order kinetics that belong to the OTOR level model.

Ultrasound assisted fabrication of SrTiO3 nanopowders: Effect of electron beam induced structural and luminescence properties for solid state lightning and high temperature dosimetry applications

Strontium titanate (SrTiO3) nanopowders are prepared by ultrasound assisted sonochemical route using Polyethylene glycol as a surfactant. The obtained product is irradiated with 8 MeV electrons with electrons dose strength of 2 kGy, 4 kGy, 6 kGy and 8 kGy. The powder X-ray diffraction studies reveals well indexed cubic structure in both pristine and electron beam irradiated samples. Morphological results evidence the spherical shaped nanopowders. The energy band gap was found to be decrease with increase of electron beam irradiation strength. The photoluminescence emission spectra of pristine and electron beam irradiated samples exhibit defects related peaks at ∼424, 444, 460, 483 and 520 nm. Upon electron beam irradiation, the Commission International de I'Eclairage color coordinates are engineered from deep blue color to cyan color. A single thermoluminescence glow peak is recorded at ∼213 °C in all the electron beam irradiated samples up to given dose range 2 kGy, 4 kGy, 6 kGy and 8 kGy. The trapping parameters (E, s) are calculated by employing various methods. Linear dose response, less fading and high reproducibility of electron beam irradiated SrTiO3 samples broadly indicated its suitability for thermoluminescence dosimetry applications.

Photo-, radio- and thermo- luminescence properties of Eu-doped BaSi2O5 glass-ceramics

The optical, radioluminescence and thermoluminescence properties of Eu-doped BaSi2O5 glass-ceramics were evaluated. The glass samples were synthesized by the conventional melt-quenching technique using a carbon crucible under reductive condition and heat-treated at different temperatures. The samples exhibit photoluminescence and radioluminescence with a broad emission due to Eu2+, and the observed emission peaks are blue-shifted in the crystallized samples. The decay time constants are the typical values of the 5d-4f transitions of Eu2+. The glass sample shows no clear thermoluminescence glow peak while the glass-ceramic samples show an intense thermoluminescence glow peak around 180 °C. The thermoluminescence intensity monotonically increases with the irradiated X-ray dose, which covers from 0.01 to 1000 mGy.