Glow Curve Analysis Methods Research Articles

Investigations of swift heavy ion induced thermoluminescence effect, trapping parameter analysis, and density functional theory of MgB4O7: Eu phosphor

The present work reports swift heavy ion (SHI) induced thermoluminescence (TL) dosimetric properties and density functional theory (DFT) studies of Eu doped MgB4O7 phosphor. Comparative investigations of structural, and luminescent properties of MgB4O7:Eu phosphor upon irradiation by 100 MeV Ag7+ and Ni7+ ion beams at the varied fluence range from 1 × 1010 ion/cm2 to 5 × 1012 ion/cm2 are presented systematically. Eu doped MgB4O7 phosphor is prepared by facile hydrothermal method. X-ray diffraction pattern of the material reveals its orthorhombic structure with crystallite size of ∼30 nm. Fourier transform infrared spectroscopy (FTIR) studies demonstrate loss of crystallinity of material after the SHI irradiations. Correlation of stopping powers and projectile range calculations is performed using SRIM software. The investigated photoluminescence properties show emission bands located in the orange-red region with prominent peaks centered at ∼593 nm and ∼625 nm corresponding to 5D0→7F1 and 5D0→7F2 transitions of Eu3+ion. The influence of ion beam fluence on the photoluminescence properties has been explored. Variation in the intensity of the PL peaks without any shift in the peak positions is observed at different ion fluence. The TL glow curve of phosphor exhibits two major dosimetric peaks (a) at 185 °C and 275 °C and (b) at 172 °C and 273 °C upon Ag7+ and Ni7+ ion beam irradiation respectively. The phosphor shows fairly good linear dose response in the range of 1 × 1010 ion/cm2 to 5 × 1012 ion/cm2. Fading measurements reveal 10% and 12% fading for the irradiation of Ag7+ and Ni7+ ions respectively in two months. Trapping parameter calculations of SHI irradiated phosphors are carried out via various TL glow curve analysis methods such as, peak shape method, whole glow peak method, and glow curve deconvolution method. Efficient thermoluminescence properties of MgB4O7:Eu make it a potential phosphor material and promise to provide avenue into swift heavy ion dosimetry applications. DFT computational studies performed to obtain the electronic structure of Eu doped MgB4O7 phosphor support the experimental results of crystal structure, symmetry and electronic structure studies.

Understanding thermoluminescence kinetics in BaWO4 phosphors by glow curve analysis methods

Understanding thermoluminescence kinetics in BaWO4 phosphors by glow curve analysis methods

A comparative study on the influence of 150 MeV Ni7+, 120 MeV Ag9+, and 110 MeV Au8+ swift heavy ions on the structural and thermoluminescence properties of Y2O3: Eu3+/Tb3+ nanophosphor for dosimetric applications

Herein, a comparative study on the structural and thermoluminescence (TL) properties of Y2O3: Eu3+/Tb3+ nanophosphor is investigated under the influence of 150 MeV Ni7+, 120 MeV Ag9+, and 110 MeV Au8+ swift heavy ions (SHI) within the fluence range of 1 × 1011 to 1 × 1013 ions/cm2. With the increase in SHI irradiation, the crystallinity deteriorated owing to grain fragmentation for the SHI fluence, which was confirmed via the Hall–Williamsons relation. The loss of crystallinity of the nanophosphor after SHI irradiation was higher in the case of the Au8+ ion irradiation. Transmission electron microscopy confirmed that the SHI irradiation separated the agglomerated particles into irregularly shaped particles with reduced particle size. Infrared spectroscopy revealed Y–O stretching and C–O bending bonds. The reduction in Y–O vibration in the SHI-irradiated phosphor indicated the loss of crystallinity, and confirmed the formation of new defect centers. SRIM calculations, performed to correlate the changes in TL properties of Y2O3: Eu3+/Tb3+ nanophosphor, showed that 110 MeV Au8+ ions created higher concentration of defects. Present nanophosphor possessed good TL response toward γ-ray as well as different SHI irradiations. The TL glow curves of the virgin and SHI-irradiated nanophosphor showed increase in TL intensity as a function of ion fluence. Trapping parameters of the different SHI-irradiated nanophosphors were calculated from the TL data using various glow curve analysis methods. The obtained results indicated that the present phosphor can be used successfully in heavy ions dosimetry for space craft and air crew.

CaMoO4:Dy phosphor as effective detector for swift heavy ions – depth profile and traps characterization

This paper reports the thermoluminescence (TL) properties of CaMoO4:Dy phosphor irradiated by swift heavy ions/γ-rays. Pellets of the phosphor were irradiated by 30MeV Li3+, 75MeV C6+ and 100MeV Ag7+ ion beams at a fluence range 1×1011–1×1013ions/cm2. The depth profile of these ions was calculated using the SRIM code. The TL intensity of the ion beams irradiated phosphor was found to decrease, while going from low to high atomic number (Z) ions i.e., Li3+→Ag7+. Trapping parameters of ion irradiated phosphors were calculated from TL data using a glow curve analysis method.

A comparative investigation on ion impact parameters and TL response of Y2O3:Tb3+ nanophosphor exposed to swift heavy ions for space dosimetry

This paper reports on a comparative study on the structural and thermoluminescence (TL) modifications of Y2O3:Tb3+ phosphor induced by 150MeV Ni7+, 120MeV Ag9+ and 110MeV Au8+ swift heavy ions in the fluence range 1×1011–1×1013ions/cm2. SRIM calculations were performed in order to correlate the change in TL properties of various ions irradiated phosphors. It shows that the 110MeV Au8+ions created a high concentration of defects. X-ray diffraction, transmission electron microscopy and Fourier transform infrared spectroscopic studies confirm the loss of crystallinity of the phosphors after ions irradiation, which is high in the case of the Au8+ ion irradiation. Structural refinement by Rietveld method yields the various structural parameters of the ion irradiated phosphors. TL glow curves of the ion irradiated phosphors show a small shift in the position of the peaks along with an increase in intensity with the increase in ions fluence. Trapping parameters of the ions irradiated phosphors were calculated from the TL data using various glow curve analysis methods. The results can be correlated on the basis of the linear energy transfer of the irradiated ions. These obtained results can be used successfully in heavy ions dosimetry for space craft and air crew.

Spectral and trapping parameters of Eu3+ in Gd2O2S nanophosphor

This paper reports the structural, photometric, spectral and trapping parameters of Eu3+-doped gadolinium oxysulphide nanophosphor. The X-ray diffraction (XRD) data show the presence of the hexagonal phase of Gd2O2S and a crystallite size in nanometre range. Different structural parameters were calculated from XRD data. The Fourier transform infrared (FTIR) spectrum also confirms the formation of a compound. Scanning electron microscope studies reveal the morphology and crystallite size of the prepared phosphor. The band gap of the phosphor was calculated from diffuse reflectance spectra using the Kubelka–Munk function at 4.76 eV. The phosphor was illuminated with ultraviolet light and shows the characteristic red luminescence corresponding to 5D0→7FJ transitions of Eu3+. The Judd–Ofelt intensity parameters and spectral parameters were estimated from the photoluminescence data. The nanophosphor was irradiated with γ-rays in the dose range 15–50 Gy for thermoluminescence (TL) studies and a shifting of the peak towards lower temperatures was observed with increasing γ-dose. Trapping parameters were calculated from TL data using various glow curve analysis methods.

Natural blue thermoluminescence emission of the recently fallen meteorite in Villalbeto de la Peña (Spain)

This paper reports on the thermal stability of the natural blue thermoluminescence (TL) of a well-characterised meteorite fallen in Villalbeto de la Peña (Palencia, Spain) in January 4, 2004. The meteorite specimen exhibits a complex structure of the spectra emission a wide broad maximum peaked at about 320 °C that can be associated with consecutive breaking linking of bonds (e.g. of Al–O, Cr–O, Fe–O) from lattices of several phases, i.e., olivine, low-Ca pyroxene, plagioclase and redox reactions. The natural TL emission seems to be essentially caused by the Na–Ca plagioclase as the brighter material inside this L6 chondrite. The thermal stability tests, at different temperatures, confirm a continuous trap distribution with progressive changes in the glow curve shape, intensity and temperature position of the main peak. In consequence, the glow curve analysis methods commonly used for synthetic materials based on single-discrete traps cannot be applied for this material.

Thermal stability of the thermoluminescence trap structure of bentonite

This work reports about the thermal stability of the blue thermoluminescence (TL) of a well-characterised natural bentonite from Almeria (Spain). The main interest of this clay, mainly composed of montmorillonite, is because of its application in the field of high-level radioactive waste (HLW) repository in deep-lying rocks. As observed in other aluminosilicates, bentonite exhibits a very complex structure of the emission spectra based on a wide broad maximum peaked at approximately 265 degrees C that can be associated to physico-chemical processes such as dehydroxylation processes, consecutive breaking linking of bonds, formation of hydrolysed ions and redox reactions. The thermal stability tests performed at different temperatures confirm a continuum in the distribution of traps. Hence, the glow curve analysis methods commonly used for synthetic materials based on single discrete traps cannot be applied for this material and the kinetic parameters were fitted assuming an exponential distribution of trapped electrons.

Influence of background exposure on detection and determination limits for a TL dosimetry system based on LiF:Mg,Cu,P(GR-200A).

Thermoluminescence dosemeters are widely used to monitor personal doses. For these low dose range applications, it is important to determine the detection limit L(D) and the determination limit L(Q) of the dosimetric system. The influence of background exposure on these limits for LiF:Mg,Cu,P(GR-200A) based TL dosimetry was investigated. Both the conventional analysis and the glow curve analysis methods were used to determinate these limits. The detection limit L(D) was compared with the recording level and the investigation level. A systematic error can occur in the occupational dose evaluation when the detection limit L(D) is more than the recording level. It was found that the L(D) of the dosimetric system-based LiF:Mg,Cu,P(GR-200A) was less than the recording level for exposure time tau > or = 10 days considering an annual dose limit of 1 mSv for the public recommended in ICRP Publication 60.

Computerised glow curve analysis: a tool for routine thermoluminescence dosimetry.

The basic features of computerised glow curve analysis methods are presented, together with the advantages derived from their use for dosimetry. The rapid development of personal computers with progressively greater computation capability has permitted the application of different analysis methods for practical dosimetry. A very simple glow curve analysis method, specifically developed for the measurement of low or very low doses usually measured in personal and environmental dosimetry, is also discussed.

Application of glow curve analysis methods to radiotherapy mailed dosimetry with LiF TLD-100

Presents the results obtained in a study of LiF TLD-100 performance for mailed dosimetry in radiotherapy, using glow curve analysis for TL evaluation and reusable chips. An excellent reusability is assured by a simple thermal treatment of 1 h at 400 degrees C followed by a controlled and reproducible cooling to room temperature that accurately reproduces the sensitivity of the detectors. Particular attention was devoted to studying sensitivity changes during room temperature storage of TLD-100 detectors. These changes can be one of the major sources of uncertainty in mailed dosimetry, where long intervals can occur between detector preparation, irradiation and readout. Based on the features of the individual peak evolution during storage a rather simple method to correct for these sensitivity modifications is proposed. The analysis of the different influential factors permitted the authors to estimate a combined uncertainty for the measurement of absorbed doses within the 0.54 Gy range of 1.0%.

A Glow Curve Analysis Method for Non-Linear Heating Hot Gas Readers

A Glow Curve Analysis Method for Non-Linear Heating Hot Gas Readers

A Glow Curve Analysis Method for Non-Linear Heating Hot Gas Readers

A Glow Curve Analysis Method for Non-Linear Heating Hot Gas Readers