Investigation of thermoluminescence and kinetic parameters of CaMgB{sub 2}O{sub 5}: Dy{sup 3+} nanophosphor

Energy Technology Data Exchange (ETDEWEB)

Manhas, M. [School of Physics, Shri Mata Vaishno Devi University, Katra-182320 J& K (India); Kumar, Vinay, E-mail: vinaykumar@smvdu.ac.in [School of Physics, Shri Mata Vaishno Devi University, Katra-182320 J& K (India); Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein ZA9300 (South Africa); Ntwaeaborwa, O. M.; Swart, H. C. [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein ZA9300 (South Africa)

2016-05-06

In this paper, thermoluminescence (TL) properties of Dy{sup 3+} (1.5 mol %) doped CaMgB{sub 2}O{sub 5} nanophosphor after being exposed to ultraviolet (UV) radiations (λ=254nm) were investigated. In UV exposed samples, the thermoluminescence glow curve consists of a broad glow peak located at 380 K with a small shoulder at 507 K. A shift in glow peak temperature from 367 K to 380 K after the UV exposure for 80 min was observed, which clearly shows that glow peaks follow the second order kinetics. The TL intensity of the peaks increases with an increase in the exposure time of UV rays (10-180 min). The TL Anal program was used to analyze the glow curve. The kinetic parameters such as activation energy (E), the frequency factor (s) and the order of kinetics (b) were calculated for CaMgB{sub 2}O{sub 5}: Dy{sup 3+} nanophosphors.

Pre-exponential factor in general order kinetics of thermoluminescence and its influence on glow curves

International Nuclear Information System (INIS)

Sunta, C.M.; Ayta, W.E.F.; Chen, R.; Watanabe, S.

1997-01-01

A model of thermoluminescence kinetics based on a physically meaningful approach shows that the glow curve shapes undergo systematic changes with the change of trap occupancy (dose). In terms of the general order kinetics model it means that the kinetic order changes with sample dose. In parallel to the kinetic order, the pre-exponential factor also changes. In contrast to these results the glow curves calculated from the general order kinetics model show that the peak shape remains nearly constant when the trap occupancy is changed. When appropriately defined, the pre-exponential factor also has a fixed value independent of trap occupancy. In these respects the general order kinetics model, though empirical, seems to describe the glow peak behaviour quite successfully. However, regarding the peak temperature the theoretical results both from the physical as well as the empirical model seem to diverge from the experimental observations when the experimentally determined kinetics is non-first order. (author)

Analysis of thermoluminescence kinetics of Mg2SiO4:Tb compounds employing an interactive model

International Nuclear Information System (INIS)

Marcazzo, J.; Prokic, M.; Santiago, M.; Molina, P.; Caselli, E.

2009-01-01

The kinetics involved in the thermoluminescence (TL) of Mg 2 SiO 4 :Tb compounds has been investigated by unfolding glow curves employing both the General Order model and a model that takes into account interactions among traps. The dependence of the glow curve shape on dose is only correctly described if interaction among traps is included in the analysis.

Numerical analysis of thermoluminescence glow curves

International Nuclear Information System (INIS)

Gomez Ros, J. M.; Delgado, A.

1989-01-01

This report presents a method for the numerical analysis of complex thermoluminescence glow curves resolving the individual glow peak components. The method employs first order kinetics analytical expressions and is based In a Marquart-Levenberg minimization procedure. A simplified version of this method for thermoluminescence dosimetry (TLD) is also described and specifically developed to operate whit Lithium Fluoride TLD-100. (Author). 36 refs

Application of numerical analysis methods to thermoluminescence dosimetry

International Nuclear Information System (INIS)

Gomez Ros, J. M.; Delgado, A.

1989-01-01

This report presents the application of numerical methods to thermoluminescence dosimetry (TLD), showing the advantages obtained over conventional evaluation systems. Different configurations of the analysis method are presented to operate in specific dosimetric applications of TLD, such as environmental monitoring and mailed dosimetry systems for quality assurance in radiotherapy facilities. (Author) 10 refs

Study of the thermoluminescence properties and kinetics of local natural calcium fluoride in Saudi Arabia

International Nuclear Information System (INIS)

Zarie, K.A.

2006-01-01

Thermoluminescence (TL) characteristics of local natural calcium fluoride that show light yellowish appearance obtained from a fluoride mine west of Saudi Arabia have been studied. TL glow peaks were observed at 160, 260 and 334 degree C. Thermal treatment and fading effects had been studied. The TL response was observed to increase with increasing dose, as expected, over the dose range used. The kinetic parameters were calculated to satisfy the feasibility of using the present sample as gamma -ray dosimetry

Determination of thermoluminescence kinetic parameters of thulium doped lithium calcium borate

International Nuclear Information System (INIS)

Jose, M.T.; Anishia, S.R.; Annalakshmi, O.; Ramasamy, V.

2011-01-01

For the first time kinetic parameters of thulium doped Lithium calcium borate (LCB) Thermoluminescence (TL) material are reported here. Irradiated LCB:Tm 3+ powder has revealed two intense TL glow peaks one at 510 (peak 1) and the other at 660 K (peak 2). Activation energy (E), frequency factor (s) and order of kinetics (b) of these peaks were determined by various heating rate (VHR), initial rise (IR), and peak shape (PS) methods. The trap depth and frequency factor determined for peaks 1 and 2 of LCB:Tm phosphor using VHR and IR methods are in good agreement. The average activation energy of peaks 1 and 2 obtained by these methods is 1.62 and 1.91 eV respectively. The frequency factors of peaks 1 and 2 are in the range of 10 13-16 and 10 12-14 sec -1 respectively. The E and s values estimated using the glow peak shape dependent parameters are relatively less compared to the values obtained from other methods. The large difference in these values is due to the complex nature of the glow curves. The order of the kinetics process for complex glow curve peaks could not be assigned on the basis of shape parameters alone but T m response on absorbed dose is to be considered for final confirmation. Glow peaks 1 and 2 of LCB:Tm 3+ obey first and general order kinetics respectively. - Highlights: → Trap depth and frequency factor are determined for the peaks at 510 and 660 K of LCB:Tm. → Parameters obtained by various heating rate and initial rise methods are in good agreement. → Trap depth of peak 1 and peak 2 is 1.61 eV and 1.91 eV respectively. → T m response to absorbed dose is used to distinguish a first order or non-first order kinetics.

Thermoluminescence kinetic parameters of different amount La-doped ZnB2O4

International Nuclear Information System (INIS)

Kucuk, Nil; Gozel, Aziz Halit; Yüksel, Mehmet; Dogan, Tamer; Topaksu, Mustafa

2015-01-01

The kinetic parameters of 1%, 2%, 3% and 4% La-doped ZnB 2 O 4 phosphors (i.e. ZnB 2 O 4 :0.01La, ZnB 2 O 4 :0.02La, ZnB 2 O 4 :0.03La and ZnB 2 O 4 :0.04La) synthesized by nitric acid method have been calculated. Thermoluminescence (TL) glow curves of ZnB 2 O 4 :La phosphors after beta-irradiation showed a very well defined main peak having the maximum temperature at around 200 °C and a shoulder peak at around 315 °C with a constant heating rate of 5 °C/s. The kinetic parameters of ZnB 2 O 4 :La phosphors TL glow peaks (i.e. order of kinetics (b), activation energies (E a ) and frequency factors (s)) have been determined and evaluated by Computerized Glow Curve Deconvolution (CGCD), and Peak Shape (PS) methods using the glow curve data. From the results, it can conclude that the values of E a obtained with these methods for ZnB 2 O 4 :La phosphors are consistent with each other, but the s values differ considerably. - Highlights: • Calculation of TL kinetic parameters for La-doped ZnB 2 O 4 . • La-doped ZnB 2 O 4 was synthesized by nitric acid method. • Well defined main peak at about 200 °C

A theoretical description of complex thermoluminescence curves: Pt. 1

International Nuclear Information System (INIS)

Kantorovich, L.N.; Fogel, G.M.; Gotlib, V.I.

1988-01-01

Thermoluminescence kinetics has been discussed within the framework of a band model assuming an extensive retrapping of charge carriers in comparison with their recombination. Assuming that a luminophor has one type of recombination centre and an arbitrary number of trapping centres we succeeded in analysing complex thermoluminescence curves with an arbitrary number of peaks. It has been shown for an elementary peak that its form almost coincides with the Randall-Wilkins curve, and its intensity is proportional to the square of the absorbed dose. The effect of both the processes of localised charge carriers accumulation (irradiation and isothermal decay) and their redistribution on trapping centres during the thermoluminescence process have been dealt with taking into account the form and intensity of the thermoluminescence peaks. (author)

Thermoluminescence dating method

International Nuclear Information System (INIS)

Zink, A.

2004-01-01

A crystal that is submitted to radiation stores energy and releases this energy under the form of light whenever it is heated. These 2 properties: the ability to store energy and the ability to reset the energy stored are the pillars on which time dating methods like thermoluminescence are based. A typical accuracy of the thermoluminescence method is between 5 to 7% but an accuracy of 3% can be reached with a sufficient number of measurement. This article describes the application of thermoluminescence to the dating of a series of old terra-cotta statues. This time measurement is absolute and does not require any calibration, it represents the time elapsed since the last heating of the artifact. (A.C.)

Thermoluminescent kinetic parameters of the perovskite, KMgF{sub 3}, activated with lanthanum; Parametros cineticos termoluminiscentes de la perovskita, KMgF{sub 3}, activada con lantano

Energy Technology Data Exchange (ETDEWEB)

Sepulveda M, F. [ESFM-IPN, 07738 Mexico D.F. (Mexico); Azorin N, J.; Rivera M, T. [UAM-I, 09340 Mexico D.F. (Mexico); Furetta, C.; Sanipoli, C. [Physics Department, Universita di Roma ' ' La Sapienza' ' , Piazzale A. Moro 2, 00185 Roma (Italy)

2004-07-01

The thermoluminescent curves induced by the beta radiation in the perovskite KMgF{sub 3} were investigated activated with lanthanum. The classic methods were used to determine the kinetic parameters (the kinetic order b, the activation energy E and the frequency of escape intent s) associated with the peaks of the thermoluminescent curve (Tl) in the KMgF{sub 3} activated with lanthanum after the irradiation with beta rays. The method is based on the position of the thermoluminescent peaks, obtained of the temperature change of the peak in the maximum emission caused by the change in the heating rapidity to which the samples were measured. In this work, the samples in form of pellets were re cooked previously at 400 C during one hour before irradiating them with beta particles. The Tl measures were made with a Tl reader system using three different heating rapidities and storing the glow curves. To calculate the depth of the E traps and the frequency factor s, the parameters of the glow curve were determined experimentally of the shame of the glow curve by means of the mensuration of the shame of the maximum temperature of the peak, T{sub M} like a function of the heating rapidity. The results indicate that the values of the kinetic parameters are very near among if when they are obtained indistinctly of anyone of the different methods. (Author)

Models and methods in thermoluminescence

International Nuclear Information System (INIS)

Furetta, C.

2005-01-01

This work contains a conference that was treated about the principles of the luminescence phenomena, the mathematical treatment concerning the thermoluminescent emission of light as well as the Randall-Wilkins model, the Garlick-Gibson model, the Adirovitch model, the May-Partridge model, the Braunlich-Scharman model, the mixed first and second order kinetics, the methods for evaluating the kinetics parameters such as the initial rise method, the various heating rates method, the isothermal decay method and those methods based on the analysis of the glow curve shape. (Author)

Models and methods in thermoluminescence

Energy Technology Data Exchange (ETDEWEB)

Furetta, C. [ICN, UNAM, A.P. 70-543, Mexico D.F. (Mexico)

2005-07-01

This work contains a conference that was treated about the principles of the luminescence phenomena, the mathematical treatment concerning the thermoluminescent emission of light as well as the Randall-Wilkins model, the Garlick-Gibson model, the Adirovitch model, the May-Partridge model, the Braunlich-Scharman model, the mixed first and second order kinetics, the methods for evaluating the kinetics parameters such as the initial rise method, the various heating rates method, the isothermal decay method and those methods based on the analysis of the glow curve shape. (Author)

Application of thermoluminescence measurements to detect irradiated strawberries

International Nuclear Information System (INIS)

Heide, L.; Guggenberger, R.; Bogl, K.W.

1990-01-01

The thermoluminescence intensity of unirradiated and irradiated strawberries was studied with regard to dose response, storage time, and different varieties. An identification method could finally be developed. Further investigations were carried out to determine the origin of the thermoluminescence effect, which was found to be attributable to mineral grains adhering to the sample surface

Thermoluminescence kinetic analysis and dosimetry features of MgSO4:Dy and MgSO4:Cu nano-rods

International Nuclear Information System (INIS)

Zahedifar, M.; Almasifard, F.; Sadeghi, E.; Biroon, M. Kashefi; Ramazani- Moghaddam-Arani, A.

2016-01-01

MgSO 4 :Dy and MgSO 4 :Cu nano-rods (NRs) were synthesized for the first time by semi co- precipitation method. X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) were utilized for sample characterization. The optimum amount of dysprosium and copper concentrations were obtained both at 0.1 mol% in MgSO 4 :Dy and MgSO 4 :Cu NRs. T m -T stop and computerized glow curve deconvolution (CGCD) methods were used for identifying the number of component glow peaks and kinetic parameters of the synthesized NRs. Initial rise and variable heating rate methods were also used to ensure the reliability of obtained kinetic parameters. Results show that the TL sensitivity of MgSO 4 :Dy is about 7 times more than that of magnesium sulfate doped with Cu. The TL dose response of MgSO 4 :Dy and MgSO 4 :Cu NRs are linear up to absorbed dose of 10 KGy. Other TL dosimetry characteristics of the produced NRs are also presented and discussed. - Highlights: • MgSO4:Dy and MgSO4:Cu nano-rods were synthesized for the first time. • Thermoluminescence dosimetry properties were studied. • The nano-phosphors showed linear dose response up to very high dose levels. • The synthesized nano-rods have potential application for high dose dosimetry.

Assessment of CVD diamond as a thermoluminescence dosemeter material

International Nuclear Information System (INIS)

Borchi, E.; Furetta, C.; Leroy, C.

1996-01-01

Diamond has a low atomic number (Z = 6) and is therefore essentially soft tissue (Z = 7.4) equivalent. As such, diamond is an attractive material for applications in dosimetry in which the radiation absorption in the sensor material should be as close as possible to that of soft tissue. Synthetic diamond prepared by chemical vapour deposition (CVD) offers an attractive option for this application. The aim of the present work is to report results on the thermoluminescence (TL) properties of CVD diamond samples. The annealing procedures, the linearity of the TL response as a function of dose, a short-term fading experiment and some kinetic properties have been investigated and are reported here. (Author)

Thermoluminescent properties of CVD diamond: applications to ionising radiation dosimetry

International Nuclear Information System (INIS)

Petitfils, A.

2007-09-01

Remarkable properties of synthetic diamond (human soft tissue equivalence, chemical stability, non-toxicity) make this material suitable for medical application as thermoluminescent dosimeter (TLD). This work highlights the interest of this material as radiotherapy TLD. In the first stage of this work, we looked after thermoluminescent (TL) and dosimetric properties of polycrystalline diamond made by Chemically Vapor Deposited (CVD) synthesis. Dosimetric characteristics are satisfactory as TLD for medical application. Luminescence thermal quenching on diamond has been investigated. This phenomenon leads to a decrease of dosimetric TL peak sensitivity when the heating rate increases. The second part of this work analyses the use of synthetic diamond as TLD in radiotherapy. Dose profiles, depth dose distributions and the cartography of an electron beam obtained with our samples are in very good agreement with results from an ionisation chamber. It is clearly shown that CVD) diamond is of interest to check beams of treatment accelerators. The use of these samples in a control of treatment with Intensity Modulated Radiation Therapy underlines good response of synthetic diamond in high dose gradient areas. These results indicate that CVD diamond is a promising material for radiotherapy dosimetry. (author)

Thermoluminescence kinetic features of Lithium Iodide (LiI) single crystal grown by vertical Bridgman technique

Science.gov (United States)

Daniel, D. Joseph; Kim, H. J.; Kim, Sunghwan; Khan, Sajid

2017-08-01

Single crystal of pure Lithium Iodide (LiI) has been grown from melt by using the vertical Bridgman technique. Thermoluminescence (TL) Measurements were carried out at 1 K/s following X-ray irradiation. The TL glow curve consists of a dominant peak at (peak-maximum Tm) 393 K and one low temperature peak of weaker intensity at 343 K. The order of kinetics (b), activation energy (E), and the frequency factor (S) for a prominent TL glow peak observed around 393 K for LiI crystals are reported for the first time. The peak shape analysis of the glow peak indicates the kinetics to be of the first order. The value of E is calculated using various standard methods such as initial rise (IR), whole glow peak (WGP), peak shape (PS), computerized glow curve deconvolution (CGCD) and Variable Heating rate (VHR) methods. An average value of 1.06 eV is obtained in this case. In order to validate the obtained parameters, numerically integrated TL glow curve has been generated using experimentally determined kinetic parameters. The effective atomic number (Zeff) for this material was determined and found to be 52. X-ray induced emission spectra of pure LiI single crystal are studied at room temperature and it is found that the sample exhibit sharp emission at 457 nm and broad emission at 650 nm.

Numerical analysis of thermoluminescence glow curves; Analisis numerico de las cruvas de termoluminiscencia

Energy Technology Data Exchange (ETDEWEB)

Gomez Ros, J M; Delgado, A

1989-07-01

This report presents a method for the numerical analysis of complex thermoluminescence glow curves resolving the individual glow peak components. The method employs first order kinetics analytical expressions and is based In a Marquart-Levenberg minimization procedure. A simplified version of this method for thermoluminescence dosimetry (TLD) is also described and specifically developed to operate whit Lithium Fluoride TLD-100. (Author). 36 refs.

Determination of trapping parameters of dosimetric thermoluminescent glow peak of lithium triborate (LiB{sub 3}O{sub 5}) activated by aluminum

Energy Technology Data Exchange (ETDEWEB)

Kafadar, V. Emir [University of Gaziantep, Department of Engineering Physics, 27310 Gaziantep (Turkey); Yazici, A. Necmeddin, E-mail: yazici@gantep.edu.t [University of Gaziantep, Department of Engineering Physics, 27310 Gaziantep (Turkey); Yildirim, R. Gueler [University of Gaziantep, Department of Engineering Physics, 27310 Gaziantep (Turkey)

2009-07-15

Lithium triborate (LBO) is a newly developed ideal nonlinear optical (NLO) crystal used in laser weapon, welder, radar, tracker, surgery, communication, etc. The effective atomic number (Z{sub eff}=7.3) makes it a tissue equivalent material and this encourages studies on its thermoluminescence (TL) properties for a radiation dosimetry. The previous studies have shown that Al-doped LiB{sub 3}O{sub 5} is a promising thermoluminescent dosimetric (TLD) material for dosimetric purposes and continuous and systematic investigations to improve its quality to get ones suited for dosimeter applications are worthy. In the given study, the additive dose (AD), initial rise with partial cleaning (IR), variable heating rate (VHR), peak shape (PS), three-points method (TPM) and computerized glow deconvolution (CGCD) methods were used to determine the kinetic parameters, namely the order of kinetics (b), activation energy (E{sub a}) and the frequency factor (s) associated with the dosimetric thermoluminescent glow peak (P3) of Al-doped LiB{sub 3}O{sub 5} after different dose levels with beta-irradiation.

Thermoluminescent measurement in space radiation dosimetry

International Nuclear Information System (INIS)

Chen Mei; Qi Zhangnian; Li Xianggao; Huang Zengxin; Jia Xianghong; Wang Genliang

1999-01-01

The author introduced the space radiation environment and the application of thermoluminescent measurement in space radiation dosimetry. Space ionization radiation is charged particles radiation. Space radiation dosimetry was developed for protecting astronauts against space radiation. Thermoluminescent measurement is an excellent method used in the spaceship cabin. Also the authors mentioned the recent works here

Thermoluminescent characterization of thin films of aluminium oxide submitted to beta and gamma radiation

International Nuclear Information System (INIS)

Villagran, E.; Escobar A, L.; Camps, E.; Gonzalez, P.R.; Martinez A, L.

2002-01-01

By mean of the laser ablation technique, thin films of aluminium oxide have been deposited on kapton substrates. These films present thermoluminescent response (Tl) when they are exposed to beta and gamma radiation. The brilliance curves show two peaks between 112 C and 180 C. A dose-response relationship study was realized and the Tl kinetic parameters were determined using the computerized deconvolution of the brilliance curve (CGCD). The thin films of aluminium oxide have potential applications as ultra.thin radiation dosemeters. (Author)

Thermoluminescent properties of ZnS:Mn nanocrystalline powders

International Nuclear Information System (INIS)

Ortiz-Hernández, Arturo Agustín; Méndez García, Víctor Hugo; Pérez Arrieta, María Leticia; Ortega Sígala, José Juan

2015-01-01

Thermoluminescent ZnS nanocrystals doped with Mn 2+ ions were synthesized by chemical co-precipitation method. From X-ray diffraction studies it was observed that the synthesized nanoparticles have cubic zinc blende structure with average sizes of about 40–50 nm. Morphology was analyzed by TEM. Photoluminescence studies showed two transitions, one of them close to 396 nm and other close to 598 nm, which is enhanced with increasing dopant concentration, this behavior was also observed in the cathodoluminescence spectrum. The thermoluminescence gamma dose-response has linear behavior over dose range 5–100 mGy, the glow curve structure shows two glow peaks at 436 K and at 518 K that were taken into account to calculate the kinetic parameters using the Computerized Glow Curve Deconvolution procedure. - Highlights: • Nanocrystals in powder of ZnS:Mn were synthesized using the co-precipitation method. • The integrated TL spectra has a linear behavior on the dose range 5–100 mGy of γ-radiation. • The kinetic parameters were obtained by the CGCD procedure. • Results support the possible use of nanocrystalline ZnS:Mn as a new γ-dose nanoTLD

Thermoluminescence under an exponential heating function: I. Theory

International Nuclear Information System (INIS)

Kitis, G; Chen, R; Pagonis, V; Carinou, E; Kamenopoulou, V

2006-01-01

Constant temperature hot gas readers are widely employed in thermoluminescence dosimetry. In such readers the sample is heated according to an exponential heating function. The single glow-peak shape derived under this heating condition is not described by the TL kinetics equation corresponding to a linear heating rate. In the present work TL kinetics expressions, for first and general order kinetics, describing single glow-peak shapes under an exponential heating function are derived. All expressions were modified from their original form of I(n 0 , E, s, b, T) into I(I m , E, T m , b, T) in order to become more efficient for glow-curve deconvolution analysis. The efficiency of all algorithms was extensively tested using synthetic glow-peaks

Thermoluminescence property of LiMgF{sub 3} erbium activated phosphor

Energy Technology Data Exchange (ETDEWEB)

Munoz, I.C. [Departamento de Ciencias Quimico Biologicas, Universidad de Sonora, A.P. 130, Hermosillo, Sonora 83000 (Mexico); Cruz-Zaragoza, E., E-mail: ecruz@nucleares.unam.mx [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, A.P. 70-543, Mexico 04510 D.F. (Mexico); Favalli, A. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Furetta, C. [Touro University Rome, Division of Touro College New York, Circne Gianicolense 15-17, 00153 Rome (Italy)

2012-05-15

The perovskite-like LiMgF{sub 3}:ErF{sub 3} pellets were obtained from the melt formed by LiF and MgF{sub 2} mixed salts in the stoichiometric ratio. The perovskite material was doped with 1, 2 and 4 mol% of ErF{sub 3} impurity. The pellets samples were {sup 60}Co gamma irradiated and their thermoluminescence (TL) properties were analyzed, i.e., dose-response, fading at RT and under UV irradiation, TL signal reproducibility, and kinetic parameters. The intensity of the TL response against irradiation dose was increased remarkably by the high concentration of impurity, and a linear dose-response was observed in the range of 1-10 Gy. The fading observed at RT was about 10-30% after 24 h from irradiation. All samples were exposed from 1 to 200 Gy gamma dose range. The TL glow peaks were found around 367-376, 438-447, 509-521, and 594-611 K, when the doped samples were 1, 2 and 4 mol% of the erbium impurity concentration. The thermoluminescence kinetics parameters of the glow curves have been analyzed using the Computerized Glow Curve Deconvolution (CGCD) method. - Highlights: Black-Right-Pointing-Pointer Perovskite-like LiMgF{sub 3} pellets were doped with 1, 2, and 4 mol% of ErF{sub 3} impurity. Black-Right-Pointing-Pointer Thermoluminescence properties and kinetics parameters were analyzed. Black-Right-Pointing-Pointer Dose-response, fading at RT and under UV irradiation and reproducibility are reported. Black-Right-Pointing-Pointer Four TL glow peaks were observed between 367 and 611 K, for all samples. Black-Right-Pointing-Pointer Glow curves have been analyzed using the CGCD method.

Synthetic diamond devices for radiotherapy applications: Thermoluminescent dosimeter and ionisation chamber

International Nuclear Information System (INIS)

Descamps, C.; Tromson, D.; Mer, C.; Nesladek, M.; Bergonzo, P.

2006-01-01

In radiotherapy field, the major usage of dosimeters is in the measurement of the dose received by the patient during radiotherapy (in-vivo measurements) and in beam calibration and uniformity checks. Diamond exhibits several interesting characteristics that make it a good candidate for radiation detection. It is indeed soft-tissue equivalent (Z=6 compared to Z=7.42 for human tissue), mechanically robust and relatively insensitive to radiation damage, chemically stable and non toxic. Moreover, the recent availability of synthetic samples, grown under controlled conditions using the chemical vapour deposition (C.V.D.) technique, allowed decreasing the high cost and the long delivery time of diamond devices. Diamond can be use for off-line dosimetry as thermoluminescent dosimeters or for on-line dosimetry as ionisation chamber [2,3]. These both applications are reported here. For this study, samples were grown in the laboratory and devices were then tested under X-ray irradiations and in clinical environment under medical cobalt source. The work described in this paper was performed in the framework of the European Integrated Project M.A.E.S.T.R.O., Methods and Advanced Equipment for Simulation and Treatment in Radio-Oncology, (6. FP) which is granted by the European Commission.The first results of this study clearly show that C.V.D. diamond detectors are suitable for dosimetry in radiotherapy applications. Moreover, for both T.L. dosimeters and ionisation chambers applications, and even though the sensitivity is subsequently reduced, nitrogen incorporation in films seems to significantly improve the dosimetric characteristics of the devices. Therefore, the optimisation of the material quality appears as a very important issue in order to increase the dosimetric characteristics of devices and more particularly, for use as thermoluminescent dosimeters, other impurities (Nickel, Phosphorus) will be tested. For ionisation chamber applications, experiments with

Application of numerical methods in spectroscopy : fitting of the curve of thermoluminescence

International Nuclear Information System (INIS)

RANDRIAMANALINA, S.

1999-01-01

The method of non linear least squares is one of the mathematical tools widely employed in spectroscopy, it is used for the determination of parameters of a model. In other hand, the spline function is among fitting functions that introduce the smallest error. It is used for the calculation of the area under the curve. We present an application of these methods, with the details of the corresponding algorithms, to the fitting of the thermoluminescence curve. [fr

Dosimetric features and kinetic analysis of thermoluminescence from ultra-high molecular weight polyethylene

Science.gov (United States)

Chithambo, M. L.

2012-08-01

Thermoluminescence (TL) from beta irradiated ultra-high molecular weight polyethylene has been studied for measurements between 30 and 200 °C. An aliquot studied in this work produced TL glow curves consisting of two peaks, the main peak at 88 °C and a weaker intensity peak at 148 °C for heating at 1 °C s-1 following an excitation dose of 215 Gy. The position of the main peak is poorly reproducible for heating rates of 0.2 and 0.6 °C s-1 investigated with the peak position decreasing when the sample is freshly irradiated and the TL re-measured. The said change in peak position is however less of an effect for measurements made at 1 °C s-1 with the peak position being fairly reproducible in this case. Further measurements of the dosimetric properties of ultra-high molecular weight polyethylene showed that its dose response is linear from 26 Gy to about 161 Gy but exhibits slower growth in intensity with dose from about 860 Gy after regions of sub- and supra-linearity in between. If the TL is not measured immediately after irradiation, the signal fades with the delay approximately exponentially. In addition, a number of tests including phosphorescence analysis showed the possibility that the order of kinetics might not be unique but sensitive to several factors including measurement temperature. Thus for instance, the dependence of the peak position on the stop temperature in the partial heating procedure Tm - Tstop implied first-order kinetics but analysis of the geometrical factor μg for the same set of data gave μg = 0.46 ± 0.03 a value corresponding to characteristics somewhat intermediate between first and second order. In comparison, the results of analysis of the phosphorescence recorded at several temperatures on the rising edge of the main peak were only in agreement for measurements at 40 °C with general-order analysis suggesting second-order kinetics apply as did TL-like transformation of the monotonic phosphorescence decay. Both results were

Thermoluminescence dosimetric characteristics of thulium doped ZnB2O4 phosphor

International Nuclear Information System (INIS)

Annalakshmi, O.; Jose, M.T.; Madhusoodanan, U.; Subramanian, J.; Venkatraman, B.; Amarendra, G.; Mandal, A.B.

2014-01-01

Polycrystalline powder samples of rare earth doped Zinc borates were synthesized by high temperature solid state diffusion technique. Dosimetric characteristics of the phosphor like thermoluminescence glow curve, TL emission spectra, dose–response, fading studies, reproducibility and reusability studies were carried out on the synthesized phosphors. Among the different rare earth doped phosphors, thulium doped zinc borate was found to have a higher sensitivity. Hence detailed dosimetric characteristics of this phosphor were carried out. It is observed that the dose–response is linear from 10 mGy to 10 3 Gy in this phosphor. EPR measurements were carried out on unirradiated, gamma irradiated and annealed phosphors to identify the defect centers responsible for thermoluminescence. A TL model is proposed based on the EPR studies in these materials. Kinetic parameters were evaluated for the dosimetric peaks using various methods. The experimental results show that this phosphor can have potential applications in radiation dosimetry applications. -- Highlights: • Polycrystalline powder samples of rare earth doped zinc borates were synthesized. • Thulium was observed to be the most efficient dopant in ZnB 2 O 4 lattice. • TL intensity of the dosimetric peak is around 20 times that of TLD-100. • Based on EPR studies a TL mechanism is proposed in zinc borate. • Deconvolution of the glow curve carried out

Thermoluminescence studies of Nd doped Bi_4Ge_3O_1_2 crystals irradiated by UV and beta sources

International Nuclear Information System (INIS)

Karabulut, Y.; Canimoglu, A.; Ekdal, E.; Ayvacikli, M.; Can, N.; Karali, T.

2016-01-01

Thermoluminescence (TL) glow curves of pure and rare earth doped bismuth germanate (BGO) were investigated under UV and beta radiation. The glow curves of pure BGO crystal present different patterns for both kinds of radiation. The TL glow curves of BGO crystals doped with Nd ions are similar to that of pure BGO under UV radiation. The kinetic parameters, kinetic order (b), activation energy (E) and frequency factor (s) of the TL glow curves of pure BGO crystal have been determined by peak shape method. Activation energies of 3 peaks obtained by PS were found to be 1.81, 1.15 and 1.78, respectively. - Highlights: • Thermoluminescence properties of pure and Nd doped BGO crystals. • Irradiated by UV and beta for TL glow curve analysis. • Evaluation of kinetic parameters by PS method.

Thermoluminescence properties of Yb-Tb-doped SiO2 optical fiber subject to 6 and 10 MV photon irradiation

Science.gov (United States)

Sahini, M. H.; Wagiran, H.; Hossain, I.; Saeed, M. A.; Ali, H.

2014-08-01

This paper reports thermoluminescence characteristics of thermoluminescence dosimetry 100 chips and Yb-Tb-doped optical fibers irradiated with 6 and 10 MV photons. Thermoluminescence response of both dosimeters increases over a wide photon dose range from 0.5 to 4 Gy. Yb-Tb-doped optical fibers demonstrate useful thermoluminescence properties and represent a good candidate for thermoluminescence dosimetry application with ionizing radiation. The results of this fiber have been compared with those of commercially available standard thermoluminescence dosimetry-100 media. Commercially available Yb-Tb-doped optical fibers and said standard media are found to yield a linear relationship between dose- and thermoluminescence signal, although Yb-Tb-doped optical fibers provide only 10 % of the sensitivity of thermoluminescence dosimetry-100. With better thermoluminescence characteristics such as small size (125 μm diameter), high flexibility, easy of handling and low cost, as compared to other thermoluminescence materials, indicate that commercial Yb-Tb-doped optical fiber is a promising thermoluminescence material for variety of applications.

γ radiation thermoluminescence performance of HFCVD diamond films

International Nuclear Information System (INIS)

Gastelum, S.; Cruz-Zaragoza, E.; Melendrez, R.; Chernov, V.; Barboza-Flores, M.

2006-01-01

Polycrystalline chemically vapor deposited (CVD) diamond films have been proposed as detectors and dosimeters of ionizing radiation with prospective applications in high-energy photon dosimetry applications. We present a comparison study on the thermoluminescence (TL) properties of two diamond film samples grown by the hot filament CVD method having thickness of 180 and 500 μm and exposed to γ radiation in the 1-300 Gy dose range. The 180 μm thick sample deposited on silicon substrate displayed a TL glow curve peaked at 145 deg. C. The 500 μm, which was a free standing sample, exhibited higher intensity and a well defined first order kinetics TL glow peak around 289 deg. C. Both diamond samples showed a linear dose behavior in the 1-50 Gy range and sublinear behavior for higher doses. The 180 and 500 μm samples presented about 80% and 30% TL losses in a 24 h period, respectively, with both samples showing excellent TL reproducibility. The results indicate that the 500 μm CVD diamond film exhibited a good TL behavior adequate for γ radiation dosimetry

Thermoluminescence of SrAl_2O_4:Eu"2"+, Dy"3"+: dosimetric characteristics and evidence of glow-peak collocation

International Nuclear Information System (INIS)

Chithambo, M.L.

2016-01-01

The thermoluminescence of SrAl_2O_4:Eu"2"+, Dy"3"+ consists of collocated peaks whereby a dominant component subsumes subsidiary ones to such an extent that they appear as one; Qualitative and quantitative analysis of such cases will be described with suitable illustrative examples. The general features and qualitative kinetics properties of thermoluminescence from SrAl_2O_4:Eu"2"+, Dy"3"+ is reported. Measurements using X-ray excited optical luminescence show that stimulated luminescence from SrAl_2O_4:Eu"2"+, Dy"3"+ has two prominent emission bands, one at 475 nm and a more intense one near 575 nm, studied in this work. There are also weaker intensity emissions at 405, 510, 600 and 660 nm. The natural thermoluminescence measured at 1°C s"-"1 shows three peaks at 74, 170 and 340°C whereas 20 Gy beta-irradiation produces TL dominated by a single peak at 34°C. Analysis of this peak for its order of kinetics produces somewhat inconclusive results. The results of the partial heating procedure T_m - T_s_t_o_p are consistent with both first and second-order kinetics. On the other hand, the position of the peak is independent of dose for several ranges of doses implying that the apparently single peak consists of multiple first-order peaks. Complementary investigations using the fractional glow technique, resolution by isothermal heating and the effect of fading on the peak show that the glow-curve of SrAl_2O_4:Eu"2"+, Dy"3"+ comprises closely collocated thermoluminescence peaks. The implication of such complexity on kinetic analysis on this material and others that share this feature will be discussed. (author)

Thermoluminescence properties of Eu-doped and Eu/Dy-codoped Sr2 Al2 SiO7 phosphors.

Science.gov (United States)

Jadhaw, Akhilesh; Sonwane, Vivek D; Gour, Anubha S; Jha, Piyush

2017-11-01

We report the thermoluminescence properties of Sr 1.96 Al 2 SiO 7 :Eu 0.04 and Sr 1.92 Al 2 SiO 7 :Eu 0.04 Dy 0.04 phosphors. These phosphors were prepared by a high-temperature solid-state reaction method. The prepared phosphors were characterized by X-ray diffraction. A 254 nm source was used for ultraviolet (UV) irradiation and a 60 Co source was used for γ-irradiation. The effect of heating rate and UV-exposure were examined. The thermoluminescence temperature shifts to higher values with increasing heating rate and thermoluminescence intensity increases with increasing UV exposure time. The trapping parameters such as activation energy (E), order of kinetics and frequency factor (s) were calculated by peak shape method. The effect of γ- and UV-irradiation on thermoluminescence studies was also examined. Copyright © 2017 John Wiley & Sons, Ltd.

Food irradiation dosimetry using thermoluminescence of quartz sand

International Nuclear Information System (INIS)

Khan, H.M.; Ehlermann, D.A.E.

1993-01-01

Thermoluminescence of quartz sand, which is inert and concomitant to several food materials, has been investigated for applications in food irradiation dosimetry and detection of irradiated foods. The glow curves consist of at least three overlapping peaks from 100 to 420 C. The peak at lower temperature is not stable and decays quickly at room temperature. However, the peaks at higher temperature are stable and more useful for dosimetry work. The intensity of the peak at 360 C, measured using different optical filters, shows a linear response in the range of 0.05 to 23 kGy. Stability of these signals at different annealing temperatures has been investigated. Thermoluminescence from adhering minerals and contaminating dust in different food materials has been found useful for the detection of irradiation treatment. Since quartz is frequently one of these minerals, further computerized deconvolution of individual glow peaks from the complex glow curves of quartz sand was carried out which improves the dosimetric results. Possible applications of thermoluminescence of quartz sand in food irradiation dosimetry and detection of irradiated foods have been discussed. (orig.)

Thermoluminescence dating. Application to the chronology of volcanic ashes

International Nuclear Information System (INIS)

Pilleyre, T.

1991-09-01

Thermoluminescent (TL) dating is generally used for minerals heated in the past and can be used for absolute chronology of volcanic ashes but seems limited to less than 15.000 years. The aim of the thesis is the study of thermoluminescent properties of quartz for high doses and long irradiations using the red TL peak of quartz which is situated at high temperature (about 370 deg. C) to extend the method for higher ages. A theory, based on spatial correlation between electron and hole created during the same ionization, is developed. A chapter is devoted to dosimetry because of its importance in TL dating, especially alpha scintillation counting and the influence of humidity on the determination of annual dose. Volcanic samples are dated from 10.000 to 80.000 years before present

Development of thermoluminescence dating techniques at Oxford

International Nuclear Information System (INIS)

Fleming, S.J.

1977-01-01

The two-decade long history of thermoluminescene as a pottery dating method is surveyed with particular reference to the various problems that have been encountered in the Oxford Laboratory's research programme. Effects, such as supralinearity and radon emanation, are explained in terms of how they are measured and how their existence influences thermoluminescence (TL) dating accuracy (currently close to plus minus 7% per analysis). Illustrations of Thermoluminescence (TL) applications include a Nok culture terracotta from Nigeria and a Cambodia bronze Buddha figure of the Khmer period, dated ising the ceramic-like casting-core retained within it. (author)

Application of numerical analysis methods to thermoluminescence dosimetry; Aplicacion de metodos de analisis numerico a la dosimetria por termoluminiscencia

Energy Technology Data Exchange (ETDEWEB)

Gomez Ros, J M; Delgado, A

1989-07-01

This report presents the application of numerical methods to thermoluminescence dosimetry (TLD), showing the advantages obtained over conventional evaluation systems. Different configurations of the analysis method are presented to operate in specific dosimetric applications of TLD, such as environmental monitoring and mailed dosimetry systems for quality assurance in radiotherapy facilities. (Author) 10 refs.

Preliminary research on thermoluminescence application in complicated geological situation

International Nuclear Information System (INIS)

Gong Gelian; Liu Chunsheng

2003-01-01

Thermoluminescent phenomenon resulting from two kinds of complicated geological situation, Ordos Basin and Huainan deposits in Anhui Province, is studied by the means of thermoluminescence counting method. It is shown that: (1) there are no apparent abnormalities of natural TL detected from the rock samples selected in the first 1000 meter depth of the Earth, and these natural TL are accumulated through natural radiation effects; (2) the natural TL shows statistically obvious reducing trends for the rock samples selected under the 2000 meter depth, and even no detectable TL is found for those rocks selected at 4000 meter depth. (3) the natural TL peaks corresponding to high temperature generally shift to the direction of higher temperature for the quartz-related rock samples, and several thermal events which occurred during the geological times might be responsible for this case

THERMOLUMINESCENT DOSIMETRY

Energy Technology Data Exchange (ETDEWEB)

Malsky, Stanley J.; Amato, Charles G.; Roswit, Bernard

1963-06-15

The performance of CaF/sub 2/: Mn and LiF as thermoluminescent in vivo dosimeters is studied. The facility with which this type of dosimeter can be inserted into the body is discussed. The dosimeter is inserted into the body by trocar or catheter techniques and exposed to radiation; it is then removed and heated, and the thermoluminescence is measured and used as an indication of the absorbed dose. (T.F.H.)

Thermoluminescence dosimetric characteristics of thulium doped ZnB{sub 2}O{sub 4} phosphor

Energy Technology Data Exchange (ETDEWEB)

Annalakshmi, O. [Radiological Safety Division, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102 (India); Jose, M.T., E-mail: mtj@igcar.gov.in [Radiological Safety Division, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102 (India); Madhusoodanan, U. [Radiological Safety Division, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102 (India); Subramanian, J. [Central Leather Research Institute, Council of Scientific and Industrial Research, Chennai (India); Venkatraman, B. [Radiological Safety Division, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102 (India); Amarendra, G. [Materials Physics Division, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102 (India); Mandal, A.B. [Central Leather Research Institute, Council of Scientific and Industrial Research, Chennai (India)

2014-02-15

Polycrystalline powder samples of rare earth doped Zinc borates were synthesized by high temperature solid state diffusion technique. Dosimetric characteristics of the phosphor like thermoluminescence glow curve, TL emission spectra, dose–response, fading studies, reproducibility and reusability studies were carried out on the synthesized phosphors. Among the different rare earth doped phosphors, thulium doped zinc borate was found to have a higher sensitivity. Hence detailed dosimetric characteristics of this phosphor were carried out. It is observed that the dose–response is linear from 10 mGy to 10{sup 3} Gy in this phosphor. EPR measurements were carried out on unirradiated, gamma irradiated and annealed phosphors to identify the defect centers responsible for thermoluminescence. A TL model is proposed based on the EPR studies in these materials. Kinetic parameters were evaluated for the dosimetric peaks using various methods. The experimental results show that this phosphor can have potential applications in radiation dosimetry applications. -- Highlights: • Polycrystalline powder samples of rare earth doped zinc borates were synthesized. • Thulium was observed to be the most efficient dopant in ZnB{sub 2}O{sub 4} lattice. • TL intensity of the dosimetric peak is around 20 times that of TLD-100. • Based on EPR studies a TL mechanism is proposed in zinc borate. • Deconvolution of the glow curve carried out.

Thermoluminescence albedo-neutron dosimetry

International Nuclear Information System (INIS)

Strand, T.; Storruste, A.

1986-10-01

The report discusses neutron detection with respect to dosimetry and compares different thermoluminescent dosimetry materials for neutron dosimetry. Construction and calibration of a thermoluminescence albedo neutron dosemeter, developed by the authors, is described

Thermoluminescence in CVD diamond films: application to actinometric dosimetry

International Nuclear Information System (INIS)

Barboza-Flores, M.; Melendrez, R.; Chernov, V.; Castaneda, B.; Pedroza-Montero, M.; Gan, B.; Ahn, J.; Zhang, Q.; Yoon, S.F.

2002-01-01

Diamond is considered a tissue-equivalent material since its atomic number (Z=6) is close to the effective atomic number of biological tissue (Z=7.42). Such a situation makes it suitable for radiation detection purposes in medical applications. In the present work the analysis is reported of the thermoluminescence (TL) and dosimetric features of chemically vapour deposited (CVD) diamond film samples subjected to ultraviolet (UV) irradiation in the actinometric region. The TL glow curve shows peaks at 120, 220, 320 and 370 deg. C. The 120 and 370 deg. C peaks are too weak and the first one fades away in a few seconds after exposure. The overall room temperature fading shows a 50% TL decay 30 min after exposure. The 320 deg. C glow peak is considered to be the most adequate for dosimetric applications due to its low fading and linear TL behaviour as a function of UV dose in the 180-260 nm range. The TL excitation spectrum presents a broad band with at least two overlapped components around 205 and 220 nm. The results indicate that the TL behaviour of CVD diamond film can be a good alternative to the currently available dosemeter and detector in the actinometric region as well as in clinical and medical applications. (author)

Using the computerized glow curve deconvolution method and the R package tgcd to determination of thermoluminescence kinetic parameters of chilli powder samples by GOK model and OTOR one

Energy Technology Data Exchange (ETDEWEB)

Sang, Nguyen Duy, E-mail: ndsang@ctu.edu.vn [College of Rural Development, Can Tho University, Can Tho 270000 (Viet Nam); Faculty of Physics and Engineering Physics, University of Science, Ho Chi Minh 700000 (Viet Nam); Van Hung, Nguyen [Nuclear Research Institute, VAEI, Dalat 670000 (Viet Nam); Van Hung, Tran; Hien, Nguyen Quoc [Research and Development Center for Radiation Technology, VAEI, Ho Chi Minh 700000 (Viet Nam)

2017-03-01

Highlights: • TL analysis aims to calculate the kinetic parameters of the chilli powder. • There is difference of the kinetic parameters caused by the difference of radiation doses. • There is difference of the kinetic parameters due to applying GOK model or OTOR one. • The software R is apllied for the first time in TL glow curve analysis of the chilli powder. - Abstract: The kinetic parameters of thermoluminescence (TL) glow peaks of chilli powder irradiated by gamma rays with the different doses of 0, 4 and 8 kGy have been calculated and estimate by computerized glow curve deconvolution (CGCD) method and the R package tgcd by using the TL glow curve data. The kinetic parameters of TL glow peaks (i.e. activation energies (E), order of kinetics (b), trapping and recombination probability coefficients (R) and frequency factors (s)) are fitted by modeled general-orders of kinetics (GOK) and one trap-one recombination (OTOR). The kinetic parameters of the chilli powder are different toward the difference of the sample time-storage, radiation doses, GOK model and OTOR one. The samples spending the shorter period of storage time have the smaller the kinetic parameters values than the samples spending the longer period of storage. The results obtained as comparing the kinetic parameters values of the three samples show that the value of non-irradiated samples are lowest whereas the 4 kGy irradiated-samples’ value are greater than the 8 kGy irradiated-samples’ one time.

A critical look at the kinetic parameter values used in simulating the thermoluminescence glow-curve

Energy Technology Data Exchange (ETDEWEB)

Sadek, A.M., E-mail: dr_amrsadek@hotmail.com [Ionizing Radiation Metrology Department, National Institute for Standards, El-Haram, Giza (Egypt); Kitis, G. [Nuclear Physics and Elementary Particles Physics Section, Physics Department, Aristotle University of Thessaloniki, 54124 Thessaloniki, Makedonia (Greece)

2017-03-15

Objections against utilizing the peak fitting method in computing the kinetics parameters of thermoluminescence (TL) glow-peaks were discussed previously in the literature. These objections came through testing the accuracy of the peak fitting by applying on simulated peaks. The results showed that in some cases the simulated peaks may have unusual geometrical properties and do not reflect the real properties of TL peaks. Thereby, estimating the accuracy of the peak fitting by applying on such peaks would be misleading. Two main reasons may lead to unrealistic simulated peaks; the improper selection of the simulation inputs, and performing the TL simulation process via the heating stage only. It has been proved that considering the irradiation and the relaxation stages in the simulation process is crucial. However, there are other cases in which the analytical methods were not able to reveal the real values of the simulated peaks. These cases were successfully resolved using analytical expressions derived from the one trap-one recombination (OTOR) level model and the non-interactive multiple trap system (NMTS) model. A general conclusion can be drawn that the accuracy of the peak fitting method is critically dependent on the TL analytical expressions utilized in this method. The failure of this method in estimating the TL kinetic parameters should be attributed to the TL model equation utilized in fitting process. - Highlights: • Objections against using the TL peak fitting method are discussed. • Improper selection of simulation inputs may lead to non realistic TL peaks. • Considering the irradiation and the relaxation stages in simulation is crucial. • TL expressions could not describe TL peaks with unrealistic geometrical properties. • The accuracy of the peak fitting method depends on the model used in the fitting.

A theoretical description of complex thermoluminescence curves: 2

International Nuclear Information System (INIS)

Kantorovich, L.N.; Fogel, G.M.

1989-01-01

Thermoluminescence kinetics is discussed using a model with one type of recombination centre and an arbitrary number of trapping centre types, assuming that electron retrapping is dominant. A distinctive feature of the suggested method is that an integral equation is obtained for the one-time function z(t) through which both the intensity of the thermoluminescence curve (TLC) and the concentration of charge carriers are expressed. Using a series of approximations, which are analysed in detail, analytical solutions of the integral equation are obtained for an arbitrary elementary peak in a complex TLC consisting of a number of slightly overlapping peaks. The comparison of the theoretical results with the numerical ones obtained by the Runge-Kutta method shows that the obtained analytical expression is precise for the first peak and describes the following TLC peaks satisfactorily. The possibility of using the results of the present study for computer division of a complex TLC into elementary components, even in the case of considerably overlapping peaks, is also discussed. (author)

Thermoluminescent response of Y2O3:Ce,Eu irradiated with X-rays

International Nuclear Information System (INIS)

Sanchez J, F. del R.; Sosa A, M. A.

2017-10-01

The thermoluminescent response of various materials has been studied when irradiated with X-rays, and the parameters that characterize the order of the kinetics of the material, depth of traps and frequency have been determined. The objective of this project was to characterize the thermoluminescent response of dosimeters based on yttrium oxide (Y 2 O 3 ) irradiated with X-rays. To do this, the thermoluminescent response of the Y 2 O 3 :Ce,Eu dosimeter was measured and exposed to an X-ray radiation field; five levels of radiation were used: in the first, a potential of 53.5 kv was used and a working load of 5.6 m As, in the second: 70.0 kv, 12.5 m As; in the third: 81.0 kv, 20.0 m As; in the fourth: 109 kv, 32 m As, in the fifth: 121 kv, 80.0 m As, applying an exposure range between 17.7 and 40 R. The irradiation was performed exposing the sample at 104 cm from the focus of the X-ray tube. To obtain the readings of the thermoluminescent response, a Harshaw TLD 3500 reader was used. The data captured by the reader was processed using the WinREMS software. The deletion protocol was as follows: the dosimeters already read were placed, one hour in the Terlab MA12D muffle at a temperature of (400 ± 1) degrees centigrade, the dosimeters were removed and left at room temperature of 20 degrees centigrade for 20 minutes. Then they were placed in the Binder high temperature oven ED23 at 100 ± 1 centigrade degrees for 2 hours. The brightness curves were de convolved using the WebPlotDigitizer v 3.8 software and the individual peaks of the brightness curves were obtained. We found that: the synthesized materials presented a good thermoluminescent response when irradiated with X-rays. However, only one of the dosimeters, of Yttrium oxide doped with 0.5% Cerium, showed a relatively linear response in the applied dose range. The analysis made to the brightness curve of the Yttrium oxide doped with Cerium at 0.5%, applying the method of the three points for the parameters

New color-photographic observation of thermoluminescence from sliced rock samples

International Nuclear Information System (INIS)

Hashimoto, Tetsuo; Kimura, Kenichi; Koyanagi, Akira; Takahashi, Kuniaki; Sotobayashi, Takeshi

1983-01-01

New observation technique has been established for the thermoluminescence photography using extremely high-sensitive color films. Considering future application to the geological fields, a granite was selected as a testing material. The sliced specimens (0.5--0.7 mm in thickness), which were irradiated with a 60 Co source, were mounted on the heater attached with a thermocouple, which was connected to a microcomputer for measuring the temperature. The samples were heated in the temperature range of 80--400 0 C by operating the camera-shutter controlled with the microcomputer. Four commercially available films (Kodak-1000(ASA), -400, Sakura-400, Fuji-400) could give apparently detectable color-images of artificial thermoluminescence above a total absorbed dose of 880 Gy(88 krad). The specimens, irradiated upto 8.4 kGy(840krad), allowed easily to distinguish the distinct appearance of the thermoluminescence images depending on kinds of white mineral constituents. Moreover, such color images were changeable with the heating temperature. Sakura-400 film has proved the most colorful images from aspects of color tone although Kodak-1000 film showed the highest sensitivity. By applying this Kodak-1000, it was found that the characteristic color image due to natural thermoluminescence was significantly observed on the Precambrian granite which was exposed with natural radiation alone since its formation. This simple and interesting technique, obtainable surface information reflecting impurities and local crystal defects in addition to small mineral constituents, was named as the thermoluminescence color imaging (abbreviated to TLCI) technique by the authors and its versatile applications were discussed. (author)

Thermoluminescent dosimeter system

International Nuclear Information System (INIS)

Felice, P.E.; Gonzalez, J.L.; Seidel, J.G.

1979-01-01

An improved thermoluminescent dosimeter system and apparatus for sensing alpha particle emission is described. A thermoluminescent body is sealed between a pair of metallized plastic films. The dosimeter is mounted within a protective inverted cup or a tube closed at one end, which is disposed in a test hole for exposure to radioactive radon gas which is indicaive of uranium deposits

Unraveling thermoluminescence

CERN Document Server

Sunta, C M

2014-01-01

The book is essentially about the theoretical aspects of thermoluminescence (TL). It is structured and written in a manner which will specially be of interest to the fresh undergraduate students and young researchers planning to take up work in the field of thermoluminescence. It is arranged into seven chapters, starting with the historical growth of the subject of TL and an overview of the luminescence phenomena. A Physical model involving thermally disconnected deep traps is specially described. Using this model expressions are derived for the TL intensity growth curve, the supralinearity fa

Measurement conditions of natural soil thermoluminescence and their application in a granite type uranium deposit

International Nuclear Information System (INIS)

Chen Yue; Yang Yaxin; Liu Qingcheng

2009-01-01

A measuring method of natural soil thermoluminescence is used for prospecting of uranium deposits. The better effects are obtained by using the method, but the parameters selected have significant effects on the intensity of soil thermoluminescent. So, the measuring parameters are selected according to the different soil samples. Based on the measuring 1 000 soil samples of granite type uranium deposit,the optimum heating up program of natural soil thermoluminescence is obtained, that is, preheating, lasting heating, constant temperature and the halting heating. The parameters selected are as follows: the heating rate being 15 degree C/s, the temperatures of the first and second constant temperature being 135 degree C and 400 degree C respectively. Using the selected parameters for measuring soil samples from a known mining area in Guangdong province, the result indicates that the abnormities of thermoluminescence have corresponding relations with the underground orebodies. (authors)

Thermoluminescence of LaAlO3

International Nuclear Information System (INIS)

Morales H, A.; Zarate M, J.; Rivera M, T.; Azorin N, J.

2015-10-01

In this paper the thermoluminescent properties of doped lanthanum aluminate (LaAlO 3 ) with dysprosium ion (Dy) were studied. The thermoluminescence characteristics in the samples were obtained using an ultraviolet radiation of 220 nm. The LaAlO 3 :Dy samples were prepared by the modified Pechini method (Spray Dryer). The structural and morphological characterization was obtained by X-ray diffraction (XRD) and scanning electron microscopy (Sem) techniques respectively. The size particle composing the agglomerate was determined by Sem, agglomerated particles composed size of 2μm were observed. The thermoluminescence response of LaAlO 3 :Dy was compared with that obtained with the undoped sample. Thermoluminescence brightness curves of LaAlO 3 :Dy showed a peak centered at 185 grades C. Sensitivity of doped sample was greater, about 100 times compared with the undoped sample. Thermoluminescence response in function of the wavelength showed a maximum at 220 nm. Also the fading in thermoluminescence response was studied. (Author)

Mexican gems as thermoluminescent dosimeters

International Nuclear Information System (INIS)

Azorin N, J.

1979-01-01

The possibility of using naturally ocurring mexican gems as thermoluminescent dosimeters (TLD) was investigated. Twelve types of gems were irradiated with X and gamma rays in order to determinate their dosimetric properties. Three of these gems showed favorable thermoluminescent characteristics compared with commercial thermoluminescent dosimeters. The plots of their thermoluminescent response as a function of gamma dose are straight lines on full log paper in the dose range 10 -2 to 10 2 Gy. The energy dependence is very strong to low energies of the radiation. Their fading was found to be about 5%/yr. and they may be annealed as reused without loss in sensitivity. Therefore, these gems can be used as X and gamma radiation dosimeters. (author)

Thermoluminescence in HfO_2:Eu"3"+ powders irradiated in UV

International Nuclear Information System (INIS)

Ceron R, P. V.; Montes R, E.; Rivera M, T.; Diaz G, J. A. I.; Guzman M, J.

2016-10-01

Various inorganic compounds synthesized for photo luminescent applications have also presented a thermoluminescent (Tl) response, for example the metal oxides doped with rare earths. This property extends the use of these materials to the radiation dosimetry. For this reason, in this work the Tl response is presented in HfO_2:Eu"3"+ powders synthesized by the hydrothermal path, exposed to ultraviolet (UV) radiation of 254 nm. The kinetic parameters of its brightness curve were also calculated using the Chen expressions and the analysis method based on the shape of the curve. For the powders irradiated for 10 min the highest Tl response corresponds to the sample with 5% of the impurity, which is 6.5 times higher than the signal corresponding to the intrinsic sample. Its bright curve shows a main peak with a maximum in 148 degrees Celsius and a second order kinetics. Another test with the same material shows the Tl response against the exposure time, with a maximum in the 3 minutes. These calculations and tests constitute a first approach for the study of these powders as Tl dosimeter for UV radiation. (Author)

Thermoluminescence of Stoichiometric Magnesium-Aluminium Spinel Defects

International Nuclear Information System (INIS)

Kobyakov, V.A.; Gritsina, V.T.; Kazarinov, Yu.G.; Volokitin, V.N.

2005-01-01

The investigations of thermoluminescence of spinel single crystals MgAl 2 O 4 after UV- and X-ray irradiation was provided by using method of self consisting heating. It was shown, that observed maxima at temperatures of ∼360 and ∼530 K in UV- and green ranges of spectra, respectively, are complex and consist of several strongly overlapping partial maxima. By using method of self consisting heating we have revealed the approximate position of partial maxima, which are included in maxima of ∼360 and ∼530 K, and for some partial maxima there was obtained the order of kinetics, activation energies, and frequency factors

Thermoluminescence, a universal tool for dosimetry

International Nuclear Information System (INIS)

Barthe, J.

1999-01-01

Radio-thermoluminescence is a transient light emission occurring when certain substances, which have been exposed to ionizing radiation, are heated. Under some conditions the quantity of emitted light is proportional to the absorbed dose. This linearity allows thermoluminescence to be used in various fields such as dosimetry, geology and age determination. Dosimeters based on thermoluminescence are passive, they do not require a source of energy and they can sustain high temperatures and high levels of irradiation. Thermoluminescence has been applied for determining the dose absorbed by meteorites and lunar rocks

Thermoluminescence dating of pottery

International Nuclear Information System (INIS)

Higashimura, Takenobu; Ichikawa, Yoneta.

1978-01-01

This report is divided into two parts. The first half describes on the history of thermoluminescence dating, and the latter half, the principle and measurement examples. It was in late 1955 that the measurement of radiation dose using thermoluminescence began. The method to thermoluminescence dating was developed when it was found that most natural stones emit the thermoluminescence. About Greek earthen wares, the study of which was presented in 1961 by G. Kennedy of University of California, the dating was able to be made within the standard deviation of 10%. Since then, this dating method progressed rapidly, and a number of laboratories are now forwarding the investigation. In the samples of natural materials, intensity of thermoluminescence I is proportional to natural radiation dose D which has been absorbed by the samples, i.e. I = kD, where k is the susceptibility of thermoluminescence of the samples. Since k is different in each sample, D can be determined by irradiating the sample with β or γ ray of known dose D 0 , measuring its luminescence I 0 , and eliminating k through these two equations, because i 0 = kD 0 . Next, if t is assumed to be the time passed since a pottery was made, D is expressed as Rt, where R is the natural radiation dose per year absorbed by the pottery. Thus t is determined if R is known. The report describes on the method of measuring R. As an example, the results of measurement of the potteries excavated at Iwakura remains, Yorikura, Taishaku-kyo, are listed. Results by 14 C dating are also described for reference. (Wakatsuki, Y.)

Thermoluminescence glow curve analysis and CGCD method for erbium doped CaZrO{sub 3} phosphor

Energy Technology Data Exchange (ETDEWEB)

Tiwari, Ratnesh, E-mail: 31rati@gmail.com [Department of Physics, Bhilai Institute of Technology, Raipur, 493661 (India); Chopra, Seema [Department Physics, G.D Goenka Public School (India)

2016-05-06

The manuscript report the synthesis, thermoluminescence study at fixed concentration of Er{sup 3+} (1 mol%) doped CaZrO{sub 3} phosphor. The phosphors were prepared by modified solid state reaction method. The powder sample was characterized by thermoluminescence (TL) glow curve analysis. In TL glow curve the optimized concentration in 1mol% for UV irradiated sample. The kinetic parameters were calculated by computerized glow curve deconvolution (CGCD) techniaue. Trapping parameters gives the information of dosimetry loss in prepared phosphor and its usability in environmental monitoring and for personal monitoring. CGCD is the advance tool for analysis of complicated TL glow curves.

Method for detecting radiation dose utilizing thermoluminescent material

International Nuclear Information System (INIS)

Miller, S.D.; McDonald, J.C.; Eichner, F.N.; Durham, J.S.

1992-01-01

The amount of ionizing radiation to which a thermoluminescent material has been exposed is determined by first cooling the thermoluminescent material and then optically stimulating the thermoluminescent material by exposure to light. Visible light emitted by the thermoluminescent material as it is allowed to warm up to room temperature is detected and counted. The thermoluminescent material may be annealed by exposure to ultraviolet light. 5 figs

Thermoluminescent properties of CVD diamond: applications to ionising radiation dosimetry; Proprietes thermoluminescentes du diamant CVD: applications a la dosimetrie des rayonnements ionisants

Energy Technology Data Exchange (ETDEWEB)

Petitfils, A

2007-09-15

Remarkable properties of synthetic diamond (human soft tissue equivalence, chemical stability, non-toxicity) make this material suitable for medical application as thermoluminescent dosimeter (TLD). This work highlights the interest of this material as radiotherapy TLD. In the first stage of this work, we looked after thermoluminescent (TL) and dosimetric properties of polycrystalline diamond made by Chemically Vapor Deposited (CVD) synthesis. Dosimetric characteristics are satisfactory as TLD for medical application. Luminescence thermal quenching on diamond has been investigated. This phenomenon leads to a decrease of dosimetric TL peak sensitivity when the heating rate increases. The second part of this work analyses the use of synthetic diamond as TLD in radiotherapy. Dose profiles, depth dose distributions and the cartography of an electron beam obtained with our samples are in very good agreement with results from an ionisation chamber. It is clearly shown that CVD) diamond is of interest to check beams of treatment accelerators. The use of these samples in a control of treatment with Intensity Modulated Radiation Therapy underlines good response of synthetic diamond in high dose gradient areas. These results indicate that CVD diamond is a promising material for radiotherapy dosimetry. (author)

Thermoluminescence in KBr:D electron irradiated at room temperature

International Nuclear Information System (INIS)

Paredes Campoy, J.C.; Lopez Carranza, E.

1991-07-01

The thermoluminescence of KBr:D samples electron irradiated at room temperature after thermal annealing at 673 K for 1 hour have been studied in the temperature range 360-730 K. The experimental TL-curve was discomposed by computer analysis in seven overlapping TL peaks, giving for them the order of the kinetics of thermal stimulation, the activation energy, the frequency factor, the relative values of the electronic concentration in traps at the initial heating temperature and the temperature at the maximum of the peak. (author). 18 refs, 1 fig., 3 tabs

Interpretation of the thermoluminescent curve by means of a Fermi-Dirac distribution

International Nuclear Information System (INIS)

Nieto H, B.; Azorin N, J.; Vazquez C, G.A.

2002-01-01

This work has the purpose to present in a preliminary form an alternative of the theoretical study of the thermoluminescence phenomena as a first approach to the quantum aspect on the behavior of the systems formed by fermions which take part in the said phenomena. In that way, an analogous expression to the Randall-Wilkins more general is obtained, for kinetics of first order, taking a Fermi-Dirac distribution. (Author)

Treatment verification and in vivo dosimetry for total body irradiation using thermoluminescent and semiconductor detectors

International Nuclear Information System (INIS)

Oliveira, F.F.; Amaral, L.L.; Costa, A.M.; Netto, T.G.

2014-01-01

The objective of this work is the characterization of thermoluminescent and semiconductor detectors and their applications in treatment verification and in vivo dosimetry for total body irradiation (TBI) technique. Dose measurements of TBI treatment simulation performed with thermoluminescent detectors inserted in the holes of a “Rando anthropomorphic phantom” showed agreement with the prescribed dose. For regions of the upper and lower chest where thermoluminescent detectors received higher doses it was recommended the use of compensating dose in clinic. The results of in vivo entrance dose measurements for three patients are presented. The maximum percentual deviation between the measurements and the prescribed dose was 3.6%, which is consistent with the action level recommended by the International Commission on Radiation Units and Measurements (ICRU), i.e., ±5%. The present work to test the applicability of a thermoluminescent dosimetric system and of a semiconductor dosimetric system for performing treatment verification and in vivo dose measurements in TBI techniques demonstrated the value of these methods and the applicability as a part of a quality assurance program in TBI treatments. - Highlights: • Characterization of a semiconductor dosimetric system. • Characterization of a thermoluminescent dosimetric system. • Application of the TLDs for treatment verification in total body irradiation treatments. • Application of semiconductor detectors for in vivo dosimetry in total body irradiation treatments. • Implementation of in vivo dosimetry as a part of a quality assurance program in radiotherapy

The influence of dose on the kinetic parameters and dosimetric features of the main thermoluminescence glow peak in α-Al{sub 2}O{sub 3}:C,Mg

Energy Technology Data Exchange (ETDEWEB)

Kalita, J.M.; Chithambo, M.L., E-mail: m.chithambo@ru.ac.za

2017-03-01

Highlights: • Influence of dose on thermoluminescence features of α-Al{sub 2}O{sub 3}:C,Mg have been studied. • Kinetic parameters of the main peak are independent of dose (0.1–100 Gy). • Dose response of the main peak: 0.1–30 Gy, superlinear; 30–100 Gy, sublinear. • Fading of the main peak: ∼22% within 2400 s. • Reproducibility: coefficient of variation in the results of 10 re-cycles: >0.071%. - Abstract: The influence of dose (0.1–100 Gy) on the kinetic parameters and the dosimetric features of the main glow peak of α-Al{sub 2}O{sub 3}:C,Mg have been investigated. Thermoluminescence (TL) measured at 1 °C/s shows a very high intensity glow peak at 161 °C and six secondary peaks at 42, 72, 193, 279, 330, 370 °C respectively. Analysis shows that the main peak follows first order kinetics irrespective of the irradiation dose. The activation energy is found to be consistent at 1.37 eV and the frequency factor is of the order of 10{sup 14} s{sup −1} for any dose between 0.1 and 100 Gy. Further, the analysis for thermal quenching of the main peak of 0.1 Gy irradiated sample shows that the activation energy for thermal quenching is (0.94 ± 0.04) eV. Regarding the dosimetric features of α-Al{sub 2}O{sub 3}:C,Mg, the dose response of the main peak is superlinear within 0.1 to 30 Gy of beta dose and then it becomes sublinear up to 100 Gy. Fading analysis shows that the intensity of the main peak drops to ∼22% of its initial value within 2400 s after irradiation and thereafter to ∼14% within 64,800 s. Analysis of the reproducibility shows that the coefficient of variation in the results for 10 identical TL measurements show that reproducibility improves with increase in dose.

Thermoluminescence dosemeter for personal dose equivalent assessment

International Nuclear Information System (INIS)

Silva, T.A. da; Rosa, L.A.R. da; Campos, L.L.

1995-01-01

The possibility was investigated of utilising a Brazilian thermoluminescence individual dosemeter, usually calibrated in terms of photon dose equivalent, for the assessment of the personal dose equivalent, H p (d), at depths of 0.07 and 10 mm. The dosemeter uses four CaSO 4 :Dy thermoluminescent detectors, between different filters, as the sensitive materials. It was calibrated in gamma and X radiation fields in the energy range from 17 to 1250 keV. Linear combinations of the responses of three detectors, in this energy range, allow the evaluation of H p (0.07) and H p (10), for radiation incidence angles varying from 0 to 60 degrees, with an accuracy better than 35%. The method is not applicable to mixed photon-beta fields. (author)

Thermoluminescence studies in geology

International Nuclear Information System (INIS)

Sankaran, A.V.; Sunta, C.M.; Nambi, K.S.V.; Bapat, V.N.

1980-01-01

Even though the phenomenon of thermoluminescence is well studied, particularly over last 3 decades, its potentialities in the field of geology have not been adequately evaluated. In this report several useful applications of TL in mineralogy, petrogenesis, stratigraphy, tectonics, ore-prospecting and other branches have been identified with particular emphasis to the Indian scene. Important areas in the country that may provide the basic material for such studies are indicated at the end along with brief geological or mineralogical accounts. (auth.)

A microcomputer controlled thermoluminescence dosimetry system

International Nuclear Information System (INIS)

Huyskens, C.J.; Kicken, P.J.H.

1980-01-01

Using a microcomputer, an automatic thermoluminescence dosimetry system for personal dosimetry and thermoluminescence detector (TLD) research was developed. Process automation, statistical computation and dose calculation are provided by this microcomputer. Recording of measurement data, as well as dose record keeping for radiological workers is carried out with floppy disk. The microcomputer also provides a human/system interface by means of a video display and a printer. The main features of this dosimetry system are its low cost, high degree of flexibility, high degree of automation and the feasibility for use in routine dosimetry as well as in TLD research. The system is in use for personal dosimetry, environmental dosimetry and for TL-research work. Because of its modular set-up several components of the system are in use for other applications, too. The system seems suited for medium sized health physics groups. (author)

Influence of thermoluminescence signal for debris flow surface materials by sunlight bleaching

International Nuclear Information System (INIS)

Song Bo; Wei Mingjian; He Youbing; Zhou Rui; Zhao Qiuyue; Zhang Bin

2013-01-01

Thermoluminescence was utilized for measuring the thermoluminescence signals of the standard debris flow samples which were bleached by simulated sunlight and debris flow samples after real sunlight bleaching. The experiment results demonstrate that light bleaching phenomenon of the debris flow occurs when it experiences a period of exposure. The thermoluminescence signal of the samples weakens gradually with the increase of depth. The optical bleaching phenomenon is obvious. Within a certain depth, light bleaching phenomenon is enhanced with the increase of light intensity. The annealing depth of simulated sunlight bleaching experiment is about 1 mm, and the actual annealing depth of sunlight bleaching is about 6 mm. According to the equivalent dose variation with depth, the mud of natural debris flow can be divided into two stages. It has fundamental significance in the application of thermoluminescence dating techniques to divide the stages of debris flow sediments. (authors)

Determination of the parameters of traps in thermoluminescent dosemeters of ZrO2: Eu + Ptfe

International Nuclear Information System (INIS)

Nieto H, B.; Azorin N, J.; Rivera M, T.

2002-01-01

In this work the manufacture of dosemeters in pellets form of ZrO 2 : Eu + Ptfe is described; which after were exposed to UV radiation (260 nm) were generated the corresponding thermoluminescent curves and in the basis to the properties of symmetry of the curves it was determined the kinetic order using the Chen and the Balarin criteria. (Author)

Thermoluminescent system for low temperatures

International Nuclear Information System (INIS)

Rosa, L.A.R. da; Caldas, L.V.E.; Leite, N.G.

1988-09-01

A system for measurements of the thermoluminescent glow curve, the thermoluminescent emission spectrum and the optical absorption spectrum of solid samples, from liquid nitrogen temperature up to 473 K, is reported. A specially designed temperature programmer provides a linear heating of the sample at a wide range of selectable heating rates, as also long term steady-state temperatures for annealing and isothermal decay studies. The system operates at a pressure of 1.33 x 10 -3 Pa. Presently it is being used for lithium fluoride low temperature thermoluminescent studies. (author) [pt

Theoretical Studies on the Physical and Environmental Factors Which Govern the Thermal Fading of Thermoluminescence Signal

International Nuclear Information System (INIS)

Rasheedy, M.S.; El-Sherif, M.A.; Hefni, M.A.

2008-01-01

Thermoluminescence solid-state detector is widely used to determine the dose in personnel and environmental monitoring for radiation protection purposes, for instance in the field of nuclear power production, medicine and research. However, thermal fading is a limiting factor for a long-term application, especially where temperature is changing significantly during the accumulation period. This paper studied the influence of temperature and duration of storage after irradiation on the thermal fading of the TL signal. Also, this paper discussed the dependence of the thermal fading on the trap parameters of TL glow peak. The most important parameters, which were considered here include the order of kinetics b, the depth of the trap level E (eV) and the frequency factor S (s-1). The dependence of the thermal fading on thermal stability parameters, namely trap depths and frequency factors for the glow peaks is discussed. The variation of the thermal fading as a function of the order of kinetics is demonstrated. In addition, this paper discussed the dependence of the thermal fading on the absorbed dose in case of first-, second- and general-order kinetics. The above-mentioned studies were arranged considering the models of first-, second- and general-order of kinetics

Thermoluminescent dosimetric characterization of the perovskite, KMgF3, activated with lanthanum

International Nuclear Information System (INIS)

Sepulveda M, F.

2003-01-01

The new ICRP regulation about the Radiological Protection allows to the different groups to study new thermoluminescent materials highly sensitive for dosimetric applications (personal and environmental). This work reports the relative experimental results to the thermoluminescent characteristic of a new preparation of the fluorine perovskite activated with lanthanum absorbed in polytetrafluoroethylene (KMgF 3 : LaF 3 + Ptfe). The main thermoluminescent properties investigated were: the TL response like a function of the absorbed dose, the attainable accuracy in the dose measurement, the reproducibility of the TL readings and the threshold dose. The obtained results were compared with the requirements of the ANSI protocol for the environmental dosimetry, resulting in a very good agreement with the required yields. (Author)

Combination of archaeomagnetism and thermoluminescence for precision dating

Science.gov (United States)

Becker, H.; Göksu, H. Y.; Regulla, D. F.

Archaeomagnetic dating was applied to two chalk-burning ovens from an early medieval noble-cemetery. Usually this method allows dating by the investigation of the geomagnetic declination and inclination through the thermoremanent magnetisation of baked clay in situ. However, in this case the method resulted in multiple dates since it was not possible to distinguish the brainching of the geomagnetic secular variation curve. Thermoluminescence dating was applied to the same samples to overcome the problem of multiple dates. This first combined application of archaeomagnetism and thermoluminescence for dating yielded A.D. 670±30 for the two ovens, which dates the first stone-church at the site after a wooden predecessor archeologically dated A.D. 620-630.

Limitation of peak fitting and peak shape methods for determination of activation energy of thermoluminescence glow peaks

CERN Document Server

Sunta, C M; Piters, T M; Watanabe, S

1999-01-01

This paper shows the limitation of general order peak fitting and peak shape methods for determining the activation energy of the thermoluminescence glow peaks in the cases in which retrapping probability is much higher than the recombination probability and the traps are filled up to near saturation level. Right values can be obtained when the trap occupancy is reduced by using small doses or by post-irradiation partial bleaching. This limitation in the application of these methods has not been indicated earlier. In view of the unknown nature of kinetics in the experimental samples, it is recommended that these methods of activation energy determination should be applied only at doses well below the saturation dose.

Design and development of low cost thermoluminescence measurement system using PIC16F877 microcontroller

International Nuclear Information System (INIS)

Neelamegam, P; Rajendran, A

2006-01-01

A real time microcontroller based thermoluminescence system has been developed to measure light intensity and temperature and to control linear heating. This instruments permits to conduct investigations on thermoluminescent materials, such as alkali halides, phosphors and related compounds, which have important applications in materials science and in dosimetry. A low cost dedicated PIC16F877 based microcontroller board was employed for the hardware. The detail of its interface and software to measure thermoluminescence and to send data to PC is explained in this paper

Design and development of low cost thermoluminescence measurement system using PIC16F877 microcontroller

Energy Technology Data Exchange (ETDEWEB)

Neelamegam, P [Department of Electronics and Instrumentation Engineering, Shunmuga Arts, Science, Technology and Research Academy (SASTRA), Deemed University, Thanjavur-613 402, Tamil Nadu (India); Rajendran, A [PG and Research Department of Applied Physics, Nehru Memorial College (Autonomous), Puthanampatti-621 007, Tiruchirappalli, Tamil Nadu (India)

2006-05-15

A real time microcontroller based thermoluminescence system has been developed to measure light intensity and temperature and to control linear heating. This instruments permits to conduct investigations on thermoluminescent materials, such as alkali halides, phosphors and related compounds, which have important applications in materials science and in dosimetry. A low cost dedicated PIC16F877 based microcontroller board was employed for the hardware. The detail of its interface and software to measure thermoluminescence and to send data to PC is explained in this paper.

Application of EPR spectrometry, thermoluminescence, analyses of DNA damage and germination power for detection of irradiated foods

International Nuclear Information System (INIS)

Malec-Czechowska, K.; Stachowicz, W.; Dancewicz, A.M.; Szot, Z.

1999-01-01

The results of our own detection of irradiation in various foods: meat, poultry, fishes, spices, dried fruits, mushrooms, crops, fresh fruits and food additives are presented. The techniques for detection whether foods have been irradiated or not, such as EPR spectrometry, thermoluminescence (TL), DNA damage by ''comet'' method and ability for germination of grains has been discussed. The applicability of particular technique to specific foodstuffs has been indicated. (author)

Thermoluminescence dosimetry properties and kinetic parameters of lithium potassium borate glass co-doped with titanium and magnesium oxides

International Nuclear Information System (INIS)

Hashim, S.; Alajerami, Y.S.M.; Ramli, A.T.; Ghoshal, S.K.; Saleh, M.A.; Abdul Kadir, A.B.; Saripan, M.I.; Alzimami, K.; Bradley, D.A.; Mhareb, M.H.A.

2014-01-01

Lithium potassium borate (LKB) glasses co-doped with TiO 2 and MgO were prepared using the melt quenching technique. The glasses were cut into transparent chips and exposed to gamma rays of 60 Co to study their thermoluminescence (TL) properties. The TL glow curve of the Ti-doped material featured a single prominent peak at 230 °C. Additional incorporation of MgO as a co-activator enhanced the TL intensity threefold. LKB:Ti,Mg is a low-Z material (Z eff =8.89) with slow signal fading. Its radiation sensitivity is 12 times lower that the sensitivity of TLD-100. The dose response is linear at doses up to 10 3 Gy. The trap parameters, such as the kinetics order, activation energy, and frequency factor, which are related to the glow peak, were determined using TolAnal software. - Highlights: • Lithium potassium borate glass doped with Ti and Mg was prepared. • The material is close to soft tissues in terms of Zeff. • The radiation sensitivity is about 12 times lower than that of TLD-100. • The signal fades about 8% in 10 days and 17% in 3 months

Manufacturing polycrystalline pellets of natural quartz for applications in thermoluminescence dosimetry

Energy Technology Data Exchange (ETDEWEB)

Carvalho Junior, Alvaro Barbosa de; Khoury, Helen Jamil [Federal University of Pernambuco (UFPE), Recife, PE (Brazil). Department of Nuclear Energy; Barros, Thiago Fernandes; Guzzo, Pedro Luiz [Federal University of Pernambuco (UFPE), Recife, PE (Brazil). Department of Mining Engineering

2012-07-15

This paper describes the manufacturing process of quartz-pellets and shows their potential use as thermoluminescence dosimeters (TLD) for those applications where low-levels of ionising radiation are present. Two batches of cold-pressed pellets were produced and their resistance were evaluated by vibration tests and weight-loss measurements. The batch manufactured with 75 Multiplication-Sign 150 Micro-Sign m particles showed enough resistance to be employed as TLD. The dosimetric properties of the 310 Degree-Sign C peak appearing in the glow curves of these pellets were characterized together with commercial TLD-100 units using {gamma}- and X-ray beams with different energies. The uncertainties related to reproducibility and stability of the TL signal were better than 10%. The sensitivity and the linearity of the TL response of quartz-pellets were better than that measured for TLD-100 for doses ranging from 0.5 to 200mGy. The energy dependence of the quartz-pellets was higher than that of TLD-100 but it cannot be considered a restriction to their use in clinical procedures and industrial applications. (author)

Fatal defect in computerized glow curve deconvolution of thermoluminescence

International Nuclear Information System (INIS)

Sakurai, T.

2001-01-01

The method of computerized glow curve deconvolution (CGCD) is a powerful tool in the study of thermoluminescence (TL). In a system where the plural trapping levels have the probability of retrapping, the electrons trapped at one level can transfer from this level to another through retrapping via the conduction band during reading TL. However, at present, the method of CGCD has no affect on the electron transition between the trapping levels; this is a fatal defect. It is shown by computer simulation that CGCD using general-order kinetics thus cannot yield the correct trap parameters. (author)

Preparation of thermoluminescent materials

International Nuclear Information System (INIS)

1976-01-01

Thermoluminescent materials have been found to be suitable for measuring long term exposures to low level ionizing radiation. Oxyhalides of lanthanum, gadolinium and yttrium, including the oxychlorides and oxybromides are activated with terbium and have been found to be most efficient oxygendominated phosphors having thermoradiant efficiencies with excitation by low level ionizing radiation. Thermoluminescence response increases when the previous materials have hafnium and zirconium additives

The application of an automated thermoluminescence dosimetry system to environmental γ-dosimetry

International Nuclear Information System (INIS)

Jones, A.R.

1977-07-01

A personnel monitoring system comprising thermoluminescent dosimeters (TLDs) and an automatic TLD reader has been applied to environmental gamma dosimetry. For this purpose the accuracy of measurement at low exposures (10 to 100 mR) acquired over long periods (3 or 12 months) is important. To improve the accuracy and reliability of the system for this application the following steps were taken: the dosimeters were sensitized by irradiation with γ-rays and annealed while being irradiated with UV light; the sensitivity of each, identified dosimeter was measured and used to correct exposure measurements; the gasketted holders were modified to contain TLDs mounted on two identified plaques. Measurements of linearity, variability (with and without individual calibration) fading and energy dependence are presented. (author)

Preparation of thermoluminescent dosimeters of LiF: Mg, Cu, P + Ptfe for environmental radiological monitoring and radiodiagnosis

International Nuclear Information System (INIS)

Ramirez L, A.

1996-01-01

The necessity of finding a thermoluminescent material for measuring gamma and X radiation in applications like environmental monitoring, personnel dosimetry and biomedical sciences (radiotherapy and radiodiagnosis), but with special characteristics such as low umbral detection, independence of the energy of radiation and equivalency with the tissue. This made us think in lithium fluoride activated with magnesium, copper and phosphorous (LiF: Mg, Cu, P). In this thesis I developed this material chips like shape embedded in polytetrafluoroethylene (LiF: Mg, Cu, P+Ptfe). The chapter 1 and 2 talk about the atom is conformed and the interaction of the radiation with the matter. The requirements of Tl material, types of dosimetry system, biological effects and units of measurements are discussed in chapter 3 as well as the recommended limits of the International Commission on Radiological Protection ICRP. Chapter 4 shows aspects of the thermoluminescence phenomenon and describes, at the same time, the determination of the most important thermoluminescent parameters (kinetic order, energy or trap depth and the frequency factor). Chapter 5 describes the major characteristics and properties of Tl materials and its requirements for dosimetric use. Chapter 6 deals with the preparations of LiF: Mg, Cu, P+Ptfe chips and some tests for improving its sensitivity, describes the dosimetric tests and requirements proposed by American National Standard Institute ANSI-N545 Like: umbral of detection, homogeneity, fading, repeatability, linearity, effects of UV and fluorescent light etc. Finally in chapter 7 I do a report about analysis of results, conclusions and some recommendations. (Author)

Selected references on thermoluminescent dosemeters for personnel monitoring

International Nuclear Information System (INIS)

Lawson, Helen

1976-08-01

This bibliography contains references on: specific thermoluminescent dosemeters used for personnel dosimetry; comparisons of thermoluminescent and other dosemeters for personnel monitoring and read-out apparatus for thermoluminescent dosemeters. An appendix contains selected foreign language references. (author)

Thermoluminescence, a method for determining the date at which a ceramic object was fired

International Nuclear Information System (INIS)

Sayre, E.V.

The theory on which thermoluminescence dating of archeological ceramic objects is based and the measurement methods used are outlined. Separation of fine grain particles and quartz particles permits the determination of the thermoluminescence of each and often a more accurate age determination. The application of the method to the dating of a bronze horse from the Metropolitan Museum is described

New thermoluminescence techniques for mineral exploration

International Nuclear Information System (INIS)

Levy, P.W.; Holmes, R.J.; Ypma, P.J.; Chen, C.C.; Swiderski, H.S.

1977-01-01

The thermoluminescence of carbonate host rock in the vicinity of known lead-zinc and lead-zinc-fluorite mineralization was reexamined for possible development as an exploration technique. The measurements were made with equipment for determining the thermoluminescence spectrum at closely spaced temperature intervals. Radiation-induced thermoluminescence was also measured. Samples were studied from five localities in Mexico, Southwest Africa, and the United States. Four thermoluminescence properties were found to vary with ''distance-from-ore'' in a systematic manner. These include the glow peak intensity and temperature and the emission spectrum peak energy and full width at half-maximum. For example, in both limestone and dolomite, the high-temperature glow peak intensities are low or negligible within the ore and as the distance from the contact increases the intensity rises rapidly to a maximum, or maxima, and then decreases irregularly to constant value slightly above that in the ore. Depending on the thickness of the ore, the thermoluminescence characteristics associated with the mineralization extended from ten to a hundred or so meters from the ore host rock contact. 5 figures

The application of thermoluminescence dosimeters to studies of released activity distributions

International Nuclear Information System (INIS)

Ruden, B.I.

1969-06-01

In this report the theoretical conditions necessary for the study of the behaviour of released activity by the use of CaSO 4 : Mn thermoluminescence dosimeters are considered. A method is derived for calculating exposure distributions from drifting volume activity. The correlation between exposure distributions and concentration distributions is discussed. One of thirty experiments where Br 82 was released into water through a nozzle some metres above the bottom is described. The resulting exposure distribution was measured in a vertical plane at distances of 10, 50 and 200 metres by CaSO 4 : Mn thermoluminescence dosimeters. The measured exposures are described and discussed. The advantages and disadvantages of the technique are compared with other methods. The method using exposure measurements for the study of active release in water has given satisfactory results in practice. The measurements have been made at concentration levels which are considerably below that permissible for drinking water according to the recommendations by ICRPA special advantage with this method is that the measurements can be made simultaneously at a large number of places and that integration is possible over sufficiently long periods of time. An experiment is described where Ar 41 was released in free air at a height of one metre above ground and the resulting exposure distribution was measured in a vertical plane at 100 and 250 metres distance by CaSO 4 : Mn thermoluminescence dosimeters. Shielding problems in connection with the experiments have been small since the method permits the measurement of very small doses. An account is given of the possibility of using the beta emitting isotope Kr 85 instead of the gamma emitting Ar 41 for diffusion experiments in air. The results obtained from some experiments are presented and discussed. The thermoluminescent signal from the dosimeters are, at the same concentration and exposure time, 2.5 times greater for Kr 85 than for Ar 41. The Kr

Thermoluminescent characteristics of CaSO4:Dy+PTFE irradiated with high energy electron beams

International Nuclear Information System (INIS)

Alvarez, R.; Rivera, T.; Calderon, J. A.; Jimenez, Y.; Rodriguez, J.; Oviedo, O.; Azorin, J.

2011-10-01

In the present work thermoluminescent response of dysprosium doped calcium sulfate embedded in polytetrafluorethylene (CaSO 4 :Dy+PTFE) under high electron beam irradiations from linear accelerator for clinical applications was investigated. The irradiations were carried out using high electron beams (6 to 18 MeV) from a linear accelerator Varian, C linac 2300C/D, for clinical practice purpose. The electron irradiations were obtained by using the water solid in order to guarantee electronic equilibrium conditions. Field shaping for electron beams was obtained with electron cones. Glow curve and other thermoluminescent characteristics of CaSO 4 :Dy+PTFE were conducted under high electron beams irradiations. The thermoluminescent response of the pellets showed and intensity peak centered at around 235 C. Thermoluminescent response of CaSO 4 :Dy+PTFE as a function of high electron absorbed dose showed a linearity in a wide range. To obtain reproducibility characteristic, a set of pellets were exposed repeatedly for the same electron absorbed dose. The results obtained in this study can suggest the applicability of CaSO 4 :Dy+PTFE pellets for high electron beam dosimetry, provided fading is correctly accounted for. (Author)

Analysis of the thermoluminescent signal in the hydroxyapatite synthesized by the sol-gel method

International Nuclear Information System (INIS)

Mendoza A, D.; Gonzalez, P.R.; Lobato, M.; Rubio, E.; Rodriguez L, V.; Custodio, E.

2004-01-01

The physical properties of the ceramics are related with the chemical bonds and the crystalline structure, because the elements that constitute it can be united by ionic bonds or partially ionic giving a covalent character, this last causes that the outer layer is full of electrons. This property makes that the ceramic ones become interesting materials for thermoluminescent applications, as it demonstrates through the recent works presented on the hydroxyapatite that is a ceramic biomaterials that has shown an interesting thermoluminescent signal when being exposed to gamma radiation. In this sense, this work presents the thermoluminescent signal analysis induced by the UV and gamma radiation in a particular type of hydroxyapatite synthesized by sol gel method in which the temperature synthesis is varied. The final thermoluminescent sensitivity of materials is correlated with the crystalline degree, which is analysed through X-ray diffraction. (Author)

Thermoluminescence of laterites: applicability in dating

International Nuclear Information System (INIS)

Sankaran, A.V.; Nambi, K.S.V.; Sunta, C.M.

1985-01-01

The northward drift of the Indian subcontinent during the past geological periods brought it under the spell of humid tropical climate in post-mesozoic times which initiated chemical weathering processes (lateritization) of the ancient crustal rocks leading to neomineralization. In the present study, thermoluminescence (TL) of these 'later-formed minerals' has been used to date laterites from a number of localities in India. While the TL emission of most of the laterite samples was poor, three from Kerala, Tamil Nadu and Karnataka states, each derived from mineralogically dissimilar parent rock, yielded measurable TL and provided dates in the range of 2 to 3.6 x 10 5 yr. It is suggested that TL dating can be a promising tool for such samples, and especially those with low alpha activity (U, Th at sub-ppm levels). (author)

Thermoluminescence of laterites: applicability in dating

Energy Technology Data Exchange (ETDEWEB)

Sankaran, A V; Nambi, K S.V.; Sunta, C M

1985-01-01

The northward drift of the Indian subcontinent during the past geological periods brought it under the spell of humid tropical climate in post-mesozoic times which initiated chemical weathering processes (lateritization) of the ancient crustal rocks leading to neomineralization. In the present study, thermoluminescence (TL) of these 'later-formed minerals' has been used to date laterites from a number of localities in India. While the TL emission of most of the laterite samples was poor, three from Kerala, Tamil Nadu and Karnataka states, each derived from mineralogically dissimilar parent rock, yielded measurable TL and provided dates in the range of 2 to 3.6 x 10/sup 5/ yr. It is suggested that TL dating can be a promising tool for such samples, and especially those with low alpha activity (U, Th at sub-ppm levels).

Thermoluminescent characterization of thin films of aluminium oxide submitted to beta and gamma radiation; Caracterizacion termoluminiscente de peliculas delgadas de oxido de aluminio sometidas a radiacion beta y gamma

Energy Technology Data Exchange (ETDEWEB)

Villagran, E.; Escobar A, L.; Camps, E.; Gonzalez, P.R.; Martinez A, L. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

2002-07-01

By mean of the laser ablation technique, thin films of aluminium oxide have been deposited on kapton substrates. These films present thermoluminescent response (Tl) when they are exposed to beta and gamma radiation. The brilliance curves show two peaks between 112 C and 180 C. A dose-response relationship study was realized and the Tl kinetic parameters were determined using the computerized deconvolution of the brilliance curve (CGCD). The thin films of aluminium oxide have potential applications as ultra.thin radiation dosemeters. (Author)

Thermoluminescent Signals Caused by Disturbing Effects

International Nuclear Information System (INIS)

German, U.; Weinstein, M.; Ben-Shachar, B.

1999-01-01

One of the major sources of uncertainty in the measurement of low radiation doses by means of thermoluminescence dosemeters is the presence of disturbing thermoluminescence signals, especially luminescence caused by visible light, and by materials attached to the heated areas. Glow curves of thermoluminescence dosemeters contain useful information that can improve the accuracy and the reliability of the thermoluminescent measurements. The influence of the various disturbing effects can be recognised in the shape of the glow curves and can sometimes be separated from the exposure. Some examples are presented of signals arising from the two disturbing effects mentioned above, the signal contributed by Teflon used in the TLD-100 cards of Bicron/Harshaw and some abnormal glow curves due to dirt attached to the cards. Subtraction of the contributions due to these effects is suggested to obtain the net exposure signal. (author)

Preparation and thermoluminescent dosimetry features of high sensitivity LiF:Mg,Ce phosphor

Science.gov (United States)

Shoushtari, M. K.; Zahedifar, M.; Sadeghi, E.

2018-04-01

Thermoluminescence (TL) kinetics and dosimetry features of newly produced LiF doped with Mg and Ce were investigated. Different contents of Mg (0-1 mol%) and Ce (0-2 mol%) were introduced in host material by melting method. The most TL sensitivity of the fabricated phosphor was obtained at 0.7 and 0.05 mol% concentrations of Mg and Ce impurities, respectively. The optimum pre-irradiation annealing regime of the synthesized LiF-based material was found at 350 °C for 10 min. Kinetic parameters of LiF:Mg,Ce dosimeter were obtained using different methods of computerized glow curve deconvolution (CGCD), initial rise (IR) and isothermal decay (ID). A good conformity are observed between the results obtained from different kinetic analysis methods. Other TL features such as fading, dose response and reusability were also examined.

tgcd: An R package for analyzing thermoluminescence glow curves

Directory of Open Access Journals (Sweden)

Jun Peng

2016-01-01

Full Text Available Thermoluminescence (TL glow curves are widely used in dosimetric studies. Many commercial and free-distributed programs are used to deconvolute TL glow curves. This study introduces an open-source R package tgcd to conduct TL glow curve analysis, such as kinetic parameter estimation, glow peak simulation, and peak shape analysis. TL glow curves can be deconvoluted according to the general-order empirical expression or the semi-analytical expression derived from the one trap-one recombination center (OTOR model based on the Lambert W function by using a modified Levenberg–Marquardt algorithm from which any of the parameters can be constrained or fixed. The package provides an interactive environment to initialize parameters and offers an automated “trial-and-error” protocol to obtain optimal fit results. First-order, second-order, and general-order glow peaks (curves are simulated according to a number of simple kinetic models. The package was developed using a combination of Fortran and R programming languages to improve efficiency and flexibility.

Thermoluminescence studies of natural and doped calcium fluoride phosphors

International Nuclear Information System (INIS)

El Kolaly, M.A.

1977-01-01

The various aspects of thermoluminescence (TL) of calcium fluoride phosphors obtained both from natural and laboratory-grown CaF 2 crystals have been investigated in the temperature range from room temperature to 750 deg C. Dopants used in these studies were Mn, Y and lanthanide series rare earths. The aspects which have been investigated are : (1) effect of single and double doping on TL glow curves and TL emission spectra after gamma irradiation, (2) TL traps : their kinetics including evaluation of the activation energy using different techniques, their decay kinetics and their behaviour under partially filled conditions, and (3) effect of temperature on emission of intensity of X-ray induced luminescence and TL. During the course of these investigations, a new glow peak was observed at 650 deg C in natural CaF 2 . It was found that this peak could also be produced in synthetic CaF 2 doped with (Y + Sm). A new model for the TL trap has also been proposed. (M.G.B.)

Thermoluminescence in films of HfO2:Dy+3

International Nuclear Information System (INIS)

Ceron, P.; Rivera, T.; Guzman, J.; Montes, E.; Pelaez, A.; Rojas, B.; Guzman, D.; Azorin, J.; Paredes, L.

2014-08-01

In this work the thermoluminescence (TL) response of films of hafnium oxide polluted with dysprosium (HfO 2 :Dy +3 ) that were irradiated in the near UV (200 nm - 400 nm). The films were deposited by means of the ultrasonics spray pyrolysis technique on a glass substrate, using different deposit temperatures (300 grades C - 600 grades C). The best TL emission corresponded to the prepared film to 450 grades C that was exposed to a spectral irradiation of 80 μJ/(cm 2 -s) with a wave longitude of 240 nm. The TL response in function of the spectral irradiation was lineal in the studied interval (24 to 288 mJ/cm 2 ), several kinetic parameters were also calculated of the shine curve as depth of the trap (E), frequency factor (s) and order to the kinetics (b). The obtained results show that the films of HfO 2 :Dy +3 could be used as radiation monitor in the region of the near UV. (Author)

Personnel radiation monitoring by thermoluminescence dosimetry (2000-2001)

International Nuclear Information System (INIS)

Mi-Cho-Cho, Daw; Hla-Hla-Win, Daw; Thin-Thin-Kraing

2001-01-01

Thermoluminescence dosimetry service was introduced in 1991. Personnel who exposed directly or indirectly to radiation is monitored by thermoluminescent dosimeter. TL materials used for thermoluminescent dosimeter are in the form of thin disc. Personnel whole-body and extremity doses are measured by thermoluminescence dosimetry. The Harshaw Model 4500 TLD reader and Vinten 654E TLD reader are used for TLD evaluation. At present about 600 radiation workers are provided with TLD for routine monitoring. It was found that most personnel had received within permissible dose recommended by the International Commission on Radiological Protection (ICRP). (author)

Thermoluminescence of films of metal oxides and its application to the low energy ionizing radiation dosimetry

International Nuclear Information System (INIS)

Azorin N, J.; Rivera M, T.; Furetta, C.; Falcony G, C.; Martinez S, E.; Garcia H, M.

2002-01-01

The obtained results from 1997 to date in the project S tudy of the thermoluminescence of metal oxides and their application to the ionizing radiation as regards to the development of ZrO 2 and of Al 2 O 3 doped and without doped films with rare earths are presented. The obtained results irradiating ZrO 2 and of Al 2 O 3 films with ultraviolet light and visible light have been satisfactory; whereas these materials have resulted promising to measure beta particles, X-rays and low energy gamma rays. (Author)

A computerized glow curve analysis (GCA) method for WinREMS thermoluminescent dosimeter data using MATLAB

International Nuclear Information System (INIS)

Harvey, John A.; Rodrigues, Miesher L.; Kearfott, Kimberlee J.

2011-01-01

A computerized glow curve analysis (GCA) program for handling of thermoluminescence data originating from WinREMS is presented. The MATLAB program fits the glow peaks using the first-order kinetics model. Tested materials are LiF:Mg,Ti, CaF 2 :Dy, CaF 2 :Tm, CaF 2 :Mn, LiF:Mg,Cu,P, and CaSO 4 :Dy, with most having an average figure of merit (FOM) of 1.3% or less, with CaSO 4 :Dy 2.2% or less. Output is a list of fit parameters, peak areas, and graphs for each fit, evaluating each glow curve in 1.5 s or less. - Highlights: → Robust algorithm for performing thermoluminescent dosimeter glow curve analysis. → Written in MATLAB so readily implemented on variety of computers. → Usage of figure of merit demonstrated for six different materials.

Synthesis and thermoluminescence behavior of ZrO2:Eu3+ with variable concentration of Eu3+ doped phosphor

Directory of Open Access Journals (Sweden)

Raunak Kumar Tamrakar

2014-10-01

Full Text Available Cubical ZrO2 phosphor doped with the europium synthesized by conventional solid state synthesis method. The prepared phosphor was characterized by X-ray diffraction (XRD technique, field emission gun scanning electron microscopy (FEGSEM and transmission electron microscopy (TEM. In this paper, we focused on the thermoluminescence glow curves and kinetic parameters, activation energy, order of kinetics, and the frequency factor of ZrO2:Eu3+ phosphor under different doses of UV irradiations at a heating rate of 6.7 °C/s. The kinetic parameters activation energy E, the order of kinetics b, and the frequency factor s of synthesized phosphor of ZrO2:Eu3+ have been calculated by using a peak shape method.

Reactor Gamma Heat Measurements with Calorimeters and Thermoluminescence Dosimeters

DEFF Research Database (Denmark)

Haack, Karsten; Majborn, Benny

1973-01-01

Intercomparison measurements of reactor γ-ray heating were carried out with calorimeters and thermoluminescence dosimeters. Within the measurement uncertainties the two methods yield coincident results. In the actual measurement range thermoluminescence dosimeters are less accurate than calorimet......Intercomparison measurements of reactor γ-ray heating were carried out with calorimeters and thermoluminescence dosimeters. Within the measurement uncertainties the two methods yield coincident results. In the actual measurement range thermoluminescence dosimeters are less accurate than...... calorimeters, but possess advantages such as a small probe size and the possibility of making simultaneous measurements at many different positions. Hence, thermoluminescence dosimeters may constitute a valuable supplement to calorimeters for reactor γ-ray heating measurements....

Thermoluminescent of induced calcite by gamma and ultraviolet radiation

International Nuclear Information System (INIS)

Lima, J.F. de.

1987-01-01

Samples of brazilian calcite, exposed to gamma radiation in laboratory and heated at constant rate of 2.7 0 C/s, showed three glow peaks at 150, 250 and 350 0 C in their thermoluminescent emission curves. The analysis of these peaks, using different models, indicated that they follow a second order kinetics; it has been obtained, for the activation energy, 1.3, 1.5 and 1.7 eV, and, for the pre-exponential factors, 8.1 x 10 14 , 6.8 x10 13 and 2.4 x 10 12 s -1 . Although the total thermoluminescent emission has stayed constant, the relative height of glow peaks has changed with the temperature of annealing in the range of 400 to 700 0 C. Exposed samples were also illuminated with ultraviolet light and the resultant curves showed partial or total bleaching or some glow peaks and the growth of peaks at lower temperatures. Samples of virgin calcite, submited to increasing exposures of gamma rays, showed a corresponding enhancement of the optical absorption bands in the range of 25000 to 47000 cm -1 A subsequent illumination of these samples with ultraviolet light produced a decrease of the optical absorption bands at the same range. (author) [pt

Thermoluminescent and optical processes in alkaline halogenides dosemeters contaminated with Europium

International Nuclear Information System (INIS)

Barboza F, M.; Melendrez, R.; Castaneda, B.; Pedroza M, M.; Chernov, V.; Perez S, R.; Aceves, R.

2000-01-01

Recent research results are presented about the properties of the optical processes of photo transferred thermoluminescence (TLFT), optical whitening (BO), thermoluminescence induced by light (TLL) and its effect in the thermoluminescent curve (Tl) produced by ionizing and non-ionizing radiation. The systematic analysis of all these processes, acquires a singular importance due that actually the alkaline halogenide crystals are object of intense investigations which analyse their potential applications as detectors and radiation dosemeters through stimulated optical luminescence techniques or thermoluminescence. The obtained data show that the Tl curve of material with this nature can be enormously affected by exposure of phosphorus to the environmental light or UV. This is in part due to liberation processes of charge bearers are shouted and makes a subsequent trapping in less temperature traps; at the same time that induce changes in the intensity of determined Tl bands. Additionally, also it is observed that mentioned phenomena are related as with wavelength of incident light as of the illumination time. Finally, the obtained information allows to conclude that although the illumination effect is extremely complex, it is associated and can be explained mainly with phenomena that implicate the electrons excitation trapped in form of F centers and trapping mechanisms or radioactive and non-radioactive recombination. (Author)

The Properties of CaSO{sub 4}: Mn Thermoluminescence Dosimeters

Energy Technology Data Exchange (ETDEWEB)

Bjaerngard, Bengt

1963-06-15

The properties of the radio thermoluminescence of CaSO{sub 4}:Mn, used for dosimetry of gamma and roentgen radiation, have been investigated. The light yield of the luminophore has been determined to 1.5 percent for 1 MeV gamma radiation. The dependence of the thermoluminescence light sum on the exposure, the exposure rate, and the exposure time can qualitatively be described by the first order process model, modified by a broad energy distribution of the electron trap depths. Some applications are discussed. The cheapness of the dosimeters, the convenient read-out, and the broad range of measurable exposures suggest that CaSO{sub 4}:Mn can be a valuable complement to other dosimetry systems.

Thermoluminescent response of LaAlO3:Pr

International Nuclear Information System (INIS)

Morales H, A.; Zarate M, J.; Azorin N, J.; Rivera M, T.

2015-10-01

In this study, the thermoluminescence response of doped lanthanum aluminate (LaAlO 3 ) with praseodymium ion (Pr) obtained by the Pechini method and drying by the spraying technique Spry Dryer was studied. The obtained powders were analyzed structurally by the X-ray diffraction technique; the morphological characterization was by the scanning electron microscopy technique. The obtained powders at 800 degrees C presented crystallinity and showed a Rhombohedral crystal structure, this phase was observed by X-ray diffraction patterns. Thermoluminescence response of LaAlO 3 :Pr showed a brightness curve with a peak centered at 157 degrees C. The sensitivity of the doped samples was improved about 90 times in comparison with the undoped sample. Thermoluminescence response in function of the wavelength showed a maximum at 230 nm, reproducibility of thermoluminescence response was ±50%. Also the fading in thermoluminescence response was studied. (Author)

Thermoluminescence from natural calcites

International Nuclear Information System (INIS)

Calderon, T.; Jaque, F.; Coy-yll, R.

1984-01-01

Thermoluminescence (TL) as well as absorption and EPR spectra of x-irradiated natural calcites have been obtained. Irradiation produces UV absorption bands and a decrease of the Mn 2+ EPR spectrum. A correlation of each TL peak with the bleaching steps of UV absorption bands and the recovering in intensity of the Mn 2+ EPR spectrum has been found. These experimental results support a new model for the radiation damage and thermoluminescence process in calcites. The main point in this model is that holes become trapped at impurities, and the electrons are trapped at dislocations in the form of CO 3 3- . (author)

Thermoluminescent characterization of thin films of aluminium oxide irradiated with beta particles

International Nuclear Information System (INIS)

Villagran, E.; Escobar A, L.; Camps, E.; Gonzalez, P.R.

2002-01-01

By means of the laser ablation technique has been settled thin films of aluminium oxide on kapton substrates. These films present thermoluminescent response (Tl) when being exposed to beta radiation of a Sr 90 - Y 90 source (E max = 2.28 MeV). The brilliance curves show two peaks, one of them in 112 C degrees and the other one in 180 C degrees. The peak of low temperature is faded in some hours, whereas the high temperature one is more stable, showing a fading in the 15% order after three days of the irradiation. The Tl kinetic parameters were determined using the computerized deconvolution of the brilliance curve (CGDC). The results show that the high temperature peak is composed by four peaks which obey a second order kinetics with their maximum located at 165.7, 188.1, 215.3, and 246.5 C degrees. The depth of the traps (E) has values in the interval between 1.4 and 2.0 eV. The study of the dose response relation, show that the material presents a linear behavior in a dose interval from 150 mGy to 50 Gy. The obtained thin films of aluminium oxide could be a useful tool due to their potential applications in clinical dosimetry, in the determination of distributions of doses produced by penetrating weakly radiation, as well as in interfaces dosimetry. (Author)

Thermoluminescence of sulfated zircon exposed to gamma radiation

International Nuclear Information System (INIS)

Rubio, E.; Castano, V.M.; Mendoza A, E.; Gonzalez, P.R.

2003-01-01

In this work, the thermoluminescent (Tl) signal induced by gamma radiation in zirconia and sulfated zirconia samples embedded in Ptfe pellets is reported and discussed. In this case, samples were obtained through sol-gel method using zirconium n-propoxide and H 2 SO 4 as precursors, and later were subjected to thermal treatment at 600 C to obtain, the tetragonal phase accordingly to X-ray diffraction analysis. Experimental results show that the thermoluminescent glow peak depends on both, the crystalline structure and sulfate concentration. Two maximum peaks were observed located at 147 C and 274 C arising from the electronic transitions. Tl response as a function of the absorbed dose shows a linear increase for a wide of range exposure as well as good stability in time. The high sensitivity, dose linearity and signal stability of this material open the potential possibility to be used for the dosimetry applications. (Author)

Development of a nano structured system based on zirconia and Co nanoparticles for thermoluminescent applications: sensor of gamma and UV radiation

International Nuclear Information System (INIS)

Villa S, G.

2014-01-01

Powders of zirconium IV oxide as well as systems composed of zirconia nano crystals and cobalt nanoparticles (ZrO 2 :NPCo) with dimensions of nanometers were synthesized by the sol-gel method. Zirconia and ZrO 2 :NPCo systems have crystalline structure tetragonal or monoclinic is the heat treatment was to 500 and 1000 degrees Celsius respectively. The characterization of the synthesized materials consisted of a morphological and structural analysis, the information obtained was correlated to its thermoluminescent response induced by gamma and ultraviolet radiation. Thermoluminescent behavior was analyzed on different concentrations of cobalt nanoparticles incorporated during the synthesis process of the zirconium oxide. The monoclinic structure has the highest sensitivity thermoluminescent induced by ultraviolet and gamma radiation. Moreover, the thermoluminescence intensity decreased considerably in ZrO 2 :NPCo systems and was induced the growth of a glow peak at 280 degrees Celsius. In most of the materials analyzed the relation of the thermoluminescence intensity depending the time of irradiation with ultraviolet light showed the saturation of the traps in the material after 60 s of irradiation. Using gamma radiation is observed a behavior linear in the applied dose range between 0.25 Gy and 450 Gy. The growth of a glow peak at 280 degrees Celsius is the most important change in the thermoluminescence characteristics of zirconia. The ZrO 2 :NPCo systems can be used in the development of thermoluminescent dosimeters for detecting gamma radiation fields mainly. (Author)

Characteristic of 120 degree C thermoluminescence peak of iceland spar

International Nuclear Information System (INIS)

Lu Xinwei; Han Jia

2006-01-01

The basic characteristic of 120 degree C thermoluminescence peak of iceland spar was studied. The experimental result indicates the longevity of 120 degree C thermoluminescence peak of iceland spar is about 2 h under 30 degree C. The thermoluminescence peak moves to the high temperature when the heating speed increasing. The intensity of 120 degree C thermoluminescence peak of iceland spar is directly proportional to radiation dose under 15 Gy. (authors)

Application of thermoluminescence dosimeter on the measurement of hard X-ray pulse energy spectrum

International Nuclear Information System (INIS)

Song Zhaohui; Wang Baohui; Wang Kuilu; Hei Dongwei; Sun Fengrong; Li Gang

2003-01-01

This paper introduces the application of thermoluminescence dosimeter (TLD) which composed by TLD-3500 reader and GR-100 M chips on the measurement of hard X-ray pulse energy spectrum. The idea using Filter Fluorescence Method (FFM) and TLD to measure hard X-ray pulse energy spectrum (from 10 keV to 100 keV) is discussed in details. Considering all the factors of the measuring surrounding, the measurement system of hard X-ray pulse has been devised. The calibration technique of absolute energy response of TLD is established. This method has been applied successfully on the radiation parameters measurement of the huge pulse radiation device-high-power pulser I. Hard X-ray pulse energy spectrum data of the pulser are acquired

Accuracy and precision in thermoluminescence dosimetry

International Nuclear Information System (INIS)

Marshall, T.O.

1984-01-01

The question of accuracy and precision in thermoluminescent dosimetry, particularly in relation to lithium fluoride phosphor, is discussed. The more important sources of error, including those due to the detectors, the reader, annealing and dosemeter design, are identified and methods of reducing their effects on accuracy and precision to a minimum are given. Finally, the accuracy and precision achievable for three quite different applications are discussed, namely, for personal dosimetry, environmental monitoring and for the measurement of photon dose distributions in phantoms. (U.K.)

Personal radiation monitoring with thermoluminescent dosemeters

International Nuclear Information System (INIS)

Miano, S.C.

1987-01-01

The technique of personal dosimetry used by SAPRA (Servico de Assessoria e Protecao Radiologica S/C Ltda., Brazil) is presented. Thermoluminescent monitors and CaSO 4 : Dy are used in pastilles united by teflon. Characteristics of the dosemeters are briefly reported. The system of thermoluminescent measurement, designed and constructed by SAPRA, and the system of personal monitoring are described. (M.A.C.) [pt

Study of the lifetime of the TL peaks of quartz: comparison of the deconvolution using the first order kinetic with the initial rise method

International Nuclear Information System (INIS)

RATOVONJANAHARY, A.J.F.

2005-01-01

Quartz is a thermoluminescent material which can be used for dating and/or for dosimetry. This material has been used since 60s for dating samples like pottery, flint, etc., but the method is still subject to some improvement. One of the problem of thermoluminescence dating is the estimation of the lifetime of the ''used peak'' . The application of the glow-curve deconvolution (GCD) technique for the analysis of a composite thermoluminescence glow curve into its individual glow peaks has been applied widely since the 80s. Many functions describing a single glow peak have been proposed. For analysing quartz behaviour, thermoluminescence glow-curve deconvolution (GCD) functions are compared for first order of kinetic. The free parameters of the GCD functions are the maximum peak intensity (I m ) and the maximum peak temperature (T m ), which can be obtained experimentally. The activation energy (E) is the additional free parameter. The lifetime (τ) of each glow peak, which is an important factor for dating, is calculated from these three parameters. For ''used'' ''peak'' lifetime analysis, GCD results are compared to those from initial rise method (IRM). Results vary fairly from method to method. [fr

Clay as Thermoluminescence Dosemeter in diagnostic Radiology ...

African Journals Online (AJOL)

This paper reports the investigation of the basic thermoluminescence properties of clay at x-rays in the diagnostic radiology range, including dose monitoring in abdominal radiography. Clay sourced from Calabar, Nigeria, was tested for thermoluminescence response after irradiation at diagnostic radiology doses, including ...

Thermoluminescence properties of CaO powder obtained from chicken eggshells

International Nuclear Information System (INIS)

Nagabhushana, K.R.; Lokesha, H.S.; Satyanarayana Reddy, S.; Prakash, D.; Veerabhadraswamy, M.; Bhagyalakshmi, H.; Jayaramaiah, J.R.

2017-01-01

Eggshell wastage has created serious problem in disposal of the food processing industry which has been triggered the thoughts of researchers to use wasted eggshells as good source of calcium. In the present work, calcium oxide (CaO) has been synthesized by combustion process in furnace (F–CaO) and microwave oven (M–CaO) using the source of chicken eggshells. The obtained F–CaO and M–CaO are characterized by XRD, SEM with EDX and thermoluminescence (TL) technique. XRD pattern of both the samples show cubic phase with crystallite size 45–52 nm. TL glow curves are recorded for various gamma radiation dose (300–4000 Gy). Two TL glows, a small peak at 424 K and stronger peak at 597 K are observed. TL response of M–CaO is 2.67 times higher than F–CaO sample. TL kinetic parameters are calculated by computerized curve deconvolution analysis (CCDA) and discussed. - Highlights: • Calcium oxide powders have been synthesized using chicken egg shells as raw material. • Crystallite size was found to be 45–52 nm. • CaO derived from eggshells shows good thermoluminescence TL response. • TL response of the M–CaO is 2.67 times higher than the F–CaO sample.

Depth dose curves from 90Sr+90Y clinical applicators using the thermoluminescent technique

International Nuclear Information System (INIS)

Antonio, Patricia L.; Caldas, Linda V.E.; Oliveira, Mercia L.

2009-01-01

The 90 Sr+ 90 Y beta-ray sources widely used in brachytherapy applications were developed in the 1950's. Many of these sources, called clinical applicators, are still routinely used in several Brazilian radiotherapy clinics for the treatment of superficial lesions in the skin and eyes, although they are not commercialized anymore. These applicators have to be periodically calibrated, according to international recommendations, because these sources have to be very well specified in order to reach the traceability of calibration standards. In the case of beta-ray sources, the recommended quantity is the absorbed dose rate in water at a reference distance from the source. Moreover, there are other important quantities, as the depth dose curves and the source uniformity for beta-ray plaque sources. In this work, depth dose curves were obtained and studied of five dermatological applicators, using thin thermoluminescent dosimeters of CaSO 4 :Dy and phantoms of PMMA with different thicknesses (between 1.0 mm and 5.0 mm) positioned between each applicator and the TL pellets. The depth dose curves obtained presented the expected attenuation response in PMMA, and the results were compared with data obtained for a 90 Sr+ 90 Y standard source reported by the IAEA, and they were considered satisfactory. (author)

Study of a new dosimetric radio-thermoluminescent systems

International Nuclear Information System (INIS)

Cazac, T.C.

1980-01-01

This is the first Romanian study to investigate conditions to obtain the radio-thermo-luminescent systems: MgB 4 O 7 :A(A-Nd,Sm,Eu,Dy,Tb,Dy+Sm and Tb+Sm) MgF 2 A (A=Mn,Dy,Tb,Sm,Li), their essential dosimetric characters, as well as the (MgF 2 =Mn) thermophosphorus mixture with a ( 6 LiF) lithium target. An investigation was developed upon a new category of radio-thermoluminescent detectors with low radiation energy dependence and fading, magnesjum boride activated by several elements of the lanthanides class (Nd,Sm,Eu,Dy,Tb). A new radio-thermoluminescent dosimetric system with high sensitivity and moderate dependence on energy radiation - (Mnsup(2+)) manganese activated magnesium fluoride - was also studied. The author explored application of investigated detectors MgF 2 =Mn, MgB 4 O 7 =Dy and MgB 4 O 7 :Tb in neutron dosimetry in complex gamma-neutron fields. It is deemed that by using the dosimetric systems reported in the thesis in order to measure gamma, beta and neutron radiation doses, dosimetric control can be ensured both in professional dosimetry and in nuclear accident dosimetry, as well as in various basic and applicative investigations. A modest contribution is thus made towards achieving the national nuclear program through an extension of the thermophosphorus range with practical applications in nuclear radiation dosimetry. (author)

Thermoluminescence in medical dosimetry

International Nuclear Information System (INIS)

Rivera, T.

2011-10-01

The dosimetry by thermoluminescence (Tl) is applied in the entire world for the dosimetry of ionizing radiations specially to personal and medical dosimetry. This dosimetry method has been very interesting for measures in vivo because the Tl dosimeters have the advantage of being very sensitive in a very small volume and they are also equivalent to tissue and they do not need additional accessories (for example, cable, electrometer, etc.) The main characteristics of the diverse Tl materials to be used in the radiation measures and practical applications are: the Tl curve, the share homogeneity, the signal stability after the irradiation, precision and exactitude, the response in function with the dose and the energy influence. In this work a brief summary of the advances of the radiations dosimetry is presented by means of the thermally stimulated luminescence and its application to the dosimetry in radiotherapy. (Author)

Thermoluminescence of metal oxides and its applications to the dosimetry of low energy ionizing radiation

International Nuclear Information System (INIS)

Azorin N, J.; Rivera M, T.; Falcony G, C.; Martinez S, E.; Garcia H, M.

1999-01-01

There are presented the results obtained since 1997 at present in the project Study of the thermoluminescence of metal oxides and its applications to the dosimetry of ionizing radiation. Its have been developed ZrO 2 films without doping and doped with Eu, Tb, and Mn as well as Al 2 O 3 films without doping and doped with Na. The results obtained to the irradiated films of ZrO 2 with ultraviolet and visible lights have been satisfactory. The Al 2 O 3 in film form showed to be a promising material for the measuring ultraviolet light and the pellets of ZrO 2 + Ptfe for X-rays and low energy gamma rays. (Author)

Thermoluminescence of thin films deposited by laser ablation; Termoluminiscencia de peliculas delgadas depositadas por ablacion laser

Energy Technology Data Exchange (ETDEWEB)

Escobar A, L.; Camps, E.; Arrieta, A.; Romero, S.; Gonzalez, P.R.; Olea M, O.; Diaz E, R. [Depto. de Fisica, ININ, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

2003-07-01

Materials in thin film form have received great attention in the last few years mainly because of their singular properties, which may differ significantly from their bulk attributes making them attractive for a wide variety of applications. In particular, thermoluminescence (Tl) properties of thin films have been studied recently owing to their potential applications in detection for both ionizing and non ionizing radiation. The aim of the present work is to report the synthesis and characterization of C Nx, aluminum oxide and titanium oxide thin films. Thermoluminescence response of the obtained thin films was studied after subject thin films to UV radiation (254 nm) as well as to gamma radiation (Co-60). Thermoluminescence glow curves exhibited a peak centered at 150 C for CN{sub x} whereas for titanium oxide the glow curve shows a maximum peaking at 171 C. Characterization of the physical properties of the deposited materials is presented. (Author)

Thermoluminescence dosimetry and its applications in medicine. Part 2: history and applications

International Nuclear Information System (INIS)

Kron, T.

1995-01-01

Thermoluminescence dosimetry (TLD) has been available for dosimetry of ionising radiation for nearly 100 years. The variety of materials and their different physical forms allow the determination of different radiation qualities over a wide range of absorbed dose. This makes TL dosimeters useful in radiation protection where dose levels of μ Gy are monitored as well as in radiotherapy where doses up to several Gray are to be measured. The major advantages of TL detectors are their small physical size and that no cables or auxiliary equipment is required during the dose assessment. TLD is considered to be a good method for point dose measurements in phantoms as well as for in vivo dosimetry on patients during radiotherapy treatment. As an integrative dosimetric technique, it can be applied to personal dosimetry and it lends itself to the determination of dose distributions due to multiple or moving radiation sources (e.g. conformal and dynamic radiotherapy, computed tomography). In addition, TL dosimeters are easy to transport, and they can be mailed. This makes them well suited for intercomparison of doses delivered in different institutions. The present article aims at describing the various applications TLD has found in medicine by taking into consideration the physics and practice of TLD measurements which have been discussed in the first part of this review. 198 refs., 4 tabs., 2 figs

Thermoluminescent dosimetry and assessment of personal dose

International Nuclear Information System (INIS)

Boas, J.F.; Martin, L.J.; Young, J.G.

1982-01-01

Thermoluminescence is discussed in terms of the energy band structure of a crystalline solid and the trapping of charge carriers by point defects. Some general properties of thermoluminescent materials used for dosimetry are outlined, with thermoluminescence of CaSO 4 :Dy being described in detail. The energy response function and the modification of the energy response of a dosimeter by shielding are discussed. The final section covers the connection between exposure, as recorded by a TLD badge, and the absorbed dose to various organs from gamma radiation in a uranium mine; the conversion from absorbed dose to dose equivalent; and uncertainties in assessment of dose equivalent

Relativistic thermodynamics and kinetic theory, with applications to cosmology

International Nuclear Information System (INIS)

Stewart, J.M.

1973-01-01

The discussion of relativistic thermodynamics and kinetic theory with applications to cosmology also covers the fundamentals and nonequilibrium relativistic kinetic theory and applications to cosmology and astrophysics. (U.S.)

Investigations on low temperature thermoluminescence centres in quartz

International Nuclear Information System (INIS)

Bernhardt, H.

1984-01-01

The present paper will help to understand the often investigated process of thermoluminescence of quartz which is of high complexity. A lot of traps exist in quartz crystals which compete with each other with respect to the trapping of charge carriers during the X-ray treatment. That is why a variety of processes takes place after X-irradiation at liquid nitrogen temperature (LNT) of quartz which complicate the phenomenology of low temperature thermoluminescence. This competition in the trapping process leads to the so-called 'sensibilization' or 'desensibilization' effects of thermoluminescence, respectively, which are described in this paper for the first time. This effect means the dependence of the LNT thermoluminescence intensity on a pre-irradiation dose applied at room temperature (RT). The influence of this pre-irradiation is understood assuming the saturation of competitive traps. This favours an enhanced trapping of charge carriers at LNT-(shallow) traps instead of the preferential trapping on the deep traps in the case of X-ray treatment of the as-grown crystal at LNT. To get the afore mentioned model we take into account not only thermoluminescence but also coloration, ir- and vuv-absorption measurements. (author)

Thermoluminescence of meteorites and their orbits

Science.gov (United States)

Melcher, C. L.

1981-01-01

The thermoluminescence levels of 45 ordinary chondrites are measured in order to provide information on the orbital characteristics of the meteorites before impact. Glow curves of the photon emission response of powdered samples of the meteorites to temperatures up to 550 C in the natural state and following irradiation by a laboratory test dose of 110,000 rad were obtained as functions of terrestrial age and compared to those of samples of the Pribram, Lost City and Innisfree meteorites, for which accurate orbital data is available. The thermoluminescence levels in 40 out of 42 meteorites are found to be similar to those of the three control samples, indicating that the vast majority of ordinary chondrites that survive atmospheric entry have perihelia in the range 0.8-1 AU. Of the remaining two, Farmville is observed to exhibit an unusually large gradient in thermoluminescence levels with sample depth, which may be a result of a temperature gradient arising in a slowly rotating meteorite. Finally, the thermoluminescence measured in the Malakal meteorite is found to be two orders of magnitude lower than control samples, which is best explained by thermal draining by solar heating in an orbit with a perihelion distance of 0.5 to 0.6 AU.

Recent research into thermoluminescent dosimetry

Energy Technology Data Exchange (ETDEWEB)

Nakajima, T [National Inst. of Radiological Sciences, Chiba (Japan)

1979-04-01

The trend of basic research in thermoluminescent dosimetry (TLD), the results, and developing fields in which it can be applied are reported. This trend is outlined from the viewpoint fields of application, a new trend in TLD readers, the conditions of development of new photogenic substances, and research in the radiation characteristics of photogenic substances (radiosensitivity to particle rays and ultraviolet rays, dose rate dependence, temperature dependence at irradiation, and ..gamma.. ray energy dependence). Utilization of TLD in the medical field for measurement of environmental radiation and as a monitor for workers exposed to radiation is discussed. An international comparison of dose was necessary in order to prove its universal validity.

Dental tissue as a thermoluminescence dosimetry dosimeter

International Nuclear Information System (INIS)

Solaimani, F.; Zahmatkesh, M.H.; Akhlaghpoor, Sh.

2003-01-01

Background: Thermoluminescence dosimetry is one of the dosimetry procedures used widely as routine and personal dosimeters. In order to extend this kind of dosimeters, dental tissue has been examined and was found promising as a Thermoluminescence Dosimetry dosimeter. Materials and Methods: In this study, 70 health teeth were collected. The only criterion, wich was considered for selection of the teeth, was the healthiness of them regardless of age and gender of the donors. All collected samples were washed and cleaned and milled uniformly. The final powder had a uniform grain size between 100-300 micrometer. The sample was divided into four groups. Group A and B were used for measurement of density and investigation of variation of thermoluminescent characteristics with temperature respectively. Groups C and D were used for investigation of variation of thermoluminescent intensity with dose and fading of this intensity with time. In all cases the results obtained with dental tissue were compared to a standard LiF, thermoluminescence dosimetry dosimeter. Results: It was found that, average density of the dental tissue was 1.570 g/cm 3 , which is comparable to density of LiF, which is 1.612g/cm 3 . It was also concluded that the range of 0-300 d ig C , dental tissue has a simple curve with two specific peaks at 140 and 25 d ig C respectively. The experiment also showed that, the variation of relative intensity versus dose is linear in the range of 0.04-0.1 Gy. The fading rate of dental tissue is higher than LiF but still in the acceptable range (14% per month in compare to 5.2% per month). Conclusion: Dental tissue as a natural dosimeter is comparable with Thermoluminescence Dosimetry and can be used in accidental events with a good approximation

Optimization of the preparation method of LiF: Mg, Cu, P and study of its thermoluminescent properties to be used in ionizing radiation dosimetry

International Nuclear Information System (INIS)

Gonzalez M, P.R.

1995-01-01

In this thesis the preparation and dosimetric properties of the thermoluminescence phosphor LiF doped with magnesium, copper and phosphorus are studied. In chapter 1 luminescence phenomenon in solids is described, emphasizing the importance of thermally stimulated luminescence known as thermoluminescence (TL) as well as its application in ionizing radiation dosimetry. The models used to determine the kinetics parameters in the TL phenomenon are described in chapter 2. In chapter 3, the dosimetric characteristics of a TL materials and its requirements for dosimetry are analyzed. The preparation method of LiF: Mg, Cu, P is presented in chapter 4 studying its general characteristics for dosimetry. The concentrations of dopants, glow curve structure, TL response to gamma, beta and alpha exposures are studied along with those of LiF: Mg, Cu, P prepared for other authors and with those of LiF: Mg, Ti (TLD-100). The kinetic parameters of the phosphor were determined by the deconvolution method. Pellets of this new phosphor powder were made by pressing it at room temperature and sintering in inert atmosphere at 700 Centigrade degrees. Dosimetric characteristics of these pellets were also studied. Chapter 5 presents the results and conclusions of this study. The new dosimeter exhibited three peaks in its glow curve at 140, 180 and 220 Centigrade degrees respectively. Its TL response to gamma radiation was linear from 43.5 μ Gy to 100 Gy. This dosimeter is reusable and stable without significant loss of sensitivity. Its sensitivity was about 30 times higher than that of TLD-100. Fading of this dosimeter was negligible at room temperature as well as at body temperature (37 Centigrade degrees), and 65% at 60 Centigrade degrees. In conclusion, this dosimeter meets all the requirements of the ANSI standard. These and other characteristics render this dosimeter useful in diverse applications of radiation dosimetry. (Author)

Thermoluminescence of irradiated foods

International Nuclear Information System (INIS)

Wagner, U.; Helle, N.; Boegl, K.W.; Schreiber, G.A.

1993-01-01

This report describes developments and applications of the thermoluminescence (TL) analysis of mineral contaminants in foods. Procedures are presented to obtain minerals from most different products such as pepper, mangos, shrimps and mussels. The effect of light exposure during the storage of foods on the TL intensity of minerals is examined and corresponding conclusions for routine control are drawn. It is also shown that the normalization of TL intensities - the essential step to identify irradiated samples - can not only be achieved by γ, X or β rays but also by UV radiation. The results allow the conclusion that a clear identification of any food which has been irradiated with more than 1 kGy is possible if enough minerals can be isolated. (orig.)

Application of thermoluminescence analysis for detection of irradiated foodstuffs

International Nuclear Information System (INIS)

Malec-Czechowska, K.; Dancewicz, M.; Szot, Z.

1996-01-01

Investigations on the development conditions necessary to obtain reliable results of the detection of irradiated herbs, spices, mushrooms and strawberries by thermoluminescence (Tl) method in whole samples and/or in minerals isolated from them carried out. Tl intensities of whole samples were measured between 40 an 355 C. Threshold values for non-irradiated samples were obtained by multiplying Tl values of control samples by 3 (safety factor). Samples in which Tl intensities were higher than the threshold values were identified as irradiated. In 4 out of 10 kind of herbs and spices examined the results of Tl measurements led to false identification. (author). 14 refs, 1 fig., 5 tabs

Recent advances in thermoluminescence dating

International Nuclear Information System (INIS)

Aitken, M.J.

1984-01-01

Initially the application of thermoluminescent dating was to ancient pottery and other baked clay, the detection of forgeries in art ceramics having a particularly powerful impact. In recent years there has been a growing extension of TL into non-pottery materials. Heated flints from paleolithic fire-places is one application. Another is in the dating of igneous rocks from recent volcanic events; formerly this had been impossible on account of the malign phenomenon of non-thermal ('anomalous') fading exhibited by volcanic minerals but this is now being circumvented by utilising TL in the 600 0 C region of the glow curve. TL dating has also been extended to unburnt calcite, one application being stalagmitic floors in paleolithic caves. Another recent development is the use of TL for dating aeolian sediment and some types of waterborne sediment. These developments give prospect of establishing a TL-based chronology, both for archaeology and quaternary research, extending back well beyond the range of radiocarbon, perhaps reaching a million years ago. (author)

Study of 225 deg C thermoluminescent of quartz inclusions extracted from cementitious building materials

International Nuclear Information System (INIS)

Campos, Simara S.; Almeida, Geangela M. de; Souza, Suzana O.

2009-01-01

Incidents of excessive exposure of the population to ionizing radiation could result from a nuclear explosion, the direct exposure to a source theft or loss or an accidental exposure to a source without shielding, for example. During these incidents the victims seldom are using individual protection equipment used in the measurement and control of the doses that were exposed. One of the ways found to the doses assessment due to exposure to this type of accident is the retrospective dosimetry, which determines the excessive doses of radiation exposure, whether chronological or acute, using common materials available in the public domain. The methodology for the application of retrospective dosimetry for thermoluminescence in buildings previously burned, as bricks, it is already well established. Interest is now turning to the use of cementitious building materials such as mortar and concrete to enlarge the scope of application. This study aimed to examine some of these materials and techniques for their possible application in the doses assessment from an accidental irradiation by thermoluminescence. For this the peak about 225 deg C of natural quartz and it extracted of mortar and concrete was certain your stability for the plateau and storage tests, and also the dependence of your luminescent intensity with radiation dose. Presenting a life relatively tans compared enough to that of the accumulation of natural and long radiation sign for dosimetric applications, besides other favorable characteristics, the mortar presented evidence that is possible for retrospective dosimetry through thermoluminescence. (author)

The application of thermoluminescence dosimeter on the measurement of hard X-ray pulse energy spectrum

International Nuclear Information System (INIS)

Song Zhaohui; Wang Baohui; Wang Kuilu; Hei Dongwei; Sun Fengrong; Li Gang

2001-01-01

This paper introduce the application of thermoluminescence dosimeter (TLD) which composed by TLD-3500 Reader and TLD-100M chips on the measurement of hard X-ray pulse energy spectrum. The idea, using Filter Fluorescence Method (FFM) and TLD to measure hard X-ray pulse energy spectrum (from 10 keV to 100 keV), is discussed in details. Considering all the factors of the measuring surroundings, the measurement system of hard X-ray pulse has been devised. The calibration technique of absolute energy response of TLD is established. This method has been applied successfully on the radiation parameters measurement of the huge pulse radiation device -high-power pulser I. Hard X-ray pulse energy spectrum data of the pulser are acquired

Calibration procedure for thermoluminescent dosemeters in water absorbed doses for Iridium-192 high dose rate sources

International Nuclear Information System (INIS)

Reyes Cac, Franky Eduardo

2004-10-01

Thermoluminescent dosimeters are used in brachytherapy services quality assurance programs, with the aim of guaranteeing the correct radiation dose supplied to cancer patients, as well as with the purpose of evaluating new clinical procedures. This work describes a methodology for thermoluminescent dosimeters calibration in terms of absorbed dose to water for 192 Ir high dose rate sources. The reference dose used is measured with an ionization chamber previously calibrated for 192 Ir energy quality, applying the methodology proposed by Toelli. This methodology aims to standardizing the procedure, in a similar form to that used for external radiotherapy. The work evolves the adaptation of the TRS-277 Code of the International Atomic Energy Agency, for small and big cavities, through the introduction for non-uniform experimental factor, for the absorbed dose in the neighborhood of small brachytherapy sources. In order to simulate a water medium around the source during the experimental work, an acrylic phantom was used. It guarantees the reproducibility of the ionization chamber and the thermoluminescent dosimeter's location in relation to the radiation source. The values obtained with the ionization chamber and the thermoluminescent dosimeters, exposed to a 192 Ir high dose rate source, were compared and correction factors for different source-detector distances were determined for the thermoluminescent dosimeters. A numeric function was generated relating the correction factors and the source-detector distance. These correction factors are in fact the thermoluminescent dosimeter calibration factors for the 192 Ir source considered. As a possible application of this calibration methodology for thermoluminescent dosimeters, a practical range of source-detector distances is proposed for quality control of 192 Ir high dose rate sources. (author)

Thermoluminescence dosimetry applied to quality assurance in radiotherapy, brachytherapy and radiodiagnostic

Energy Technology Data Exchange (ETDEWEB)

Marinello, G [Centre Hospitalo-Universitaire, Creteil (France). Dept. Inter-Hospitalier de Cancerologie

1996-08-01

Thermoluminescence (TL) dosimetry is very interesting for in vivo measurements because TL detectors have the advantages of being very sensitive under a very small volume and do not meet to be connected to an electrometer with an unwieldy cable. The principle of the method being briefly recalled, criteria of choice of a TL material according to the applications to be performed are given. It is shown that to be used for in vivo measurements, TL material should have the same response at room and patient temperatures and be equivalent to soft tissue, lungs or bones for the energy ranges encountered in practice. Theoretical data are provided in order to facilitate the user`s choice. The different heating processes (linear or isothermal heating kinetics, hot gas, etc.) and light detection systems of TL readers are also presented. TL manual and automatic readers commercially available in 1994, and the emission temperature and wavelength the dosimetric peaks of usual TL materials are presented in two tables, respectively. Then the principal properties of TL dosimeters to be used for in vivo measurements and their practical consequences are summarized: signal stability after irradiation, intrinsic precision, sensitivity, response with dose, dose-rate, mass and energy. At last some examples of applications as different as total body and skin irradiations, brachytherapy, diagnostic radiology and quality assurance purposes are given. (author). 35 refs, 6 figs, 4 tabs.

TELDE thermoluminescent dosimetry system

International Nuclear Information System (INIS)

Shvarts, K.K.; Nemiro, E.A.; Bichev, V.R.; Gotlib, V.I.; Grant, Z.A.; Grube, M.M.; Gubatova, D.J.

1981-01-01

The TELDE dosimetric set designed for measurement of x- and γ- rays doses with energy more than 10 keV is described. The set consists of thermoluminescent detectors from LiF (Ca, Mg, Ti). The detectors are polycrystalline pellets with diameter 3.5+-0.3 mm and thickness 2+-0.2 mm. In the thermoluminescence detectors both the peak and integral measurement methods are realized. Apart from this the TELDE set comprises the electron unit for the pre-irradiation thermal treatment of detectors, special bones for detectors storage and transportation, devices for their package in polyethelene film and containers to wear the detectors. The TELDE set allows to perform measurements on people or animals in radiobiological experiments as well as in water, solid or porous phantoms [ru

Thermoluminescence spectra measured with a Michelson interferometer

International Nuclear Information System (INIS)

Haschberger, P.

1991-01-01

A Michelson interferometer was redesigned to prove its capabilities in the measurement of short-lived, low-intensity thermoluminescence spectra. Interferograms are collected during heating up the thermoluminescent probe in a heater plate. A personal computer controls the data acquisition and processes the Fourier transform. As the results show, even a comparatively simple and limited setup leads to relevant and reproducible spectra. (author)

Thermoluminescence in alkali halides irradiated at 80K

International Nuclear Information System (INIS)

Jimenez de Castro, M.

1978-01-01

The thermoluminescence, the thermally stimulated currents and the thermal stability of the F centres induced in pure NaCl and KC1 crystals by X irradiation at 80K have been studied in detail, in the range between 80 and 300K. The thermoluminescent processes induced by illumination at 80K with F light in samples previously irradiated at room temperature has also been studied. It has been clearly observed the existence of thermoluminescent processes due to electrons and holes thermally released from traps, in which the F centres are not involved. The existence of hole-F centre recombination has not been observed. There are several thermoluminescent processes in both materials which are scribed to the recombination of F centres with mobile interstitial halogen atoms thermally released from traps, which are likely monovalent impurities in this temperature interval. The light emitting stage in these processes is originated by the formation of self trapped excitons. (Author) 66 refs

Equipment for observing thermoluminescence

International Nuclear Information System (INIS)

Sette Camara, Alexandre; Cogneau, Michel; Ristori, Christian; Vargas, Jose Israel

1971-06-01

A detailed description is given of an apparatus for investigating thermoluminescence properties. Chopping of the emitted light and subsequent amplification of the electric signal derived led to high stability and sensitivity [fr

Thermoluminescent phosphor

Science.gov (United States)

Lasky, Jerome B.; Moran, Paul R.

1978-01-01

A thermoluminescent phosphor comprising LiF doped with boron and magnesium is produced by diffusion of boron into a conventional LiF phosphor doped with magnesium. Where the boron dopant is made to penetrate only the outer layer of the phosphor, it can be used to detect shallowly penetrating radiation such as tritium beta rays in the presence of a background of more penetrating radiation.

Ag nanoparticle effects on the thermoluminescent properties of monoclinic ZrO2 exposed to ultraviolet and gamma radiation

International Nuclear Information System (INIS)

Villa-Sanchez, G; Mendoza-Anaya, D; Gutierrez-Wing, C; Perez-Hernandez, R; Gonzalez-MartInez, P R; Angeles-Chavez, C

2007-01-01

The goal of this work was to analyse ZrO 2 in the pure state and when doped with Ag nanoparticles, by electron microscopy, x-ray diffraction and thermoluminescence methods. According to the results obtained, Ag nanoparticles did not modify the morphology or the crystalline structure of the ZrO 2 . The thermoluminescent (TL) response of pure ZrO 2 showed two peaks, one at 334 K and the other at 417 K, when it was exposed to ultraviolet (UV) radiation, and at 342 and 397 K when gamma radiation was used. For ZrO 2 impregnated with Ag nanoparticles a diminished TL intensity due to nanoparticle shielding was observed, but the glow curve shape was similar. However, when Ag nanoparticles were added during the ZrO 2 synthesis, a shift of the TL peaks towards higher temperature values with reference to pure ZrO 2 was observed. A linear dependence of the integrated TL signal as a function of the irradiation dose was observed in all analysed samples. It was possible to determine some kinetic parameters, such as activation energy, kinetic order and frequency factor, using the sequential quadratic programming glow curve deconvolution; it was found that these values are highly dependent on the type of radiation used. Ag nanoparticles present in ZrO 2 also modified the kinetic parameters, mainly when they were added during the synthesis of ZrO 2 . Our results reinforce the possibilities of using pure and doped ZrO 2 as an appropriate dosimetric material in radiation physics

High dose thermoluminescence dosimetry performance of Sol-gel synthesized TiO{sub 2} phosphors

Energy Technology Data Exchange (ETDEWEB)

Salas J, Ch. J.; Cruz V, C. [Universidad de Sonora, Departamento de Investigacion en Polimeros y Materiales, Apdo. Postal 130, 83000 Hermosillo, Sonora (Mexico); Castillo U, D. M.; Flores M, K. [Universidad de Sonora, Departamento de Ciencias Quimico Biologicas, Apdo. Postal 130, 83000 Hermosillo, Sonora (Mexico); Bernal, R. [Universidad de Sonora, Departamento de Investigacion en Fisica, Apdo. Postal 5-088, 83190 Hermosillo, Sonora (Mexico); Castano, V. M., E-mail: castillouzeta@gmail.com [UNAM, Instituto de Fisica, Centro de Fisica Aplicada y Tecnologia Avanzada, Apdo. Postal 1-1010, Queretaro, Qro. (Mexico)

2015-10-15

Full text: TiO{sub 2} is a ceramic material with many applications due to their different crystalline phases (rutile, anatase and brookite). It has attracted attention in several fields because their high mechanical strength, chemical stability and ion-conducting properties. Moreover, in recent years, some research groups gained interest in the thermoluminescence features of TiO{sub 2} concerning their potential use as thermoluminescence dosimeter. In this work, we present experimental results obtained in the first stage of a long-term research project focused in the synthesis of TiO{sub 2} phosphors for dosimetric applications. The thermoluminescent characterization of samples was carried out after being exposed to beta particle irradiation. TiO{sub 2} was prepared by alkoxide sol-gel route using titanium tetrabutoxide as precursor, ethanol, water and ammonia as catalyst. Pellet-shaped samples were annealed at 700 degrees C for 6 h in air atmosphere followed by slow cooling, and then were exposed to radiation doses from 25 to 400 Gy. The glow curves display maxima located at 103 and 238 degrees C when a 5 C/s heating rate is used. From the experimental results here presented, we conclude that TiO{sub 2} is a promising material to develop high dose Tl dosimeters. (Author)

Annual radiation dose in thermoluminescence dating

International Nuclear Information System (INIS)

Li Huhou

1988-01-01

The annual radiation dose in thermoluminescence dating has been discussed. The autor gives an entirely new concept of the enviromental radiation in the thermoluminescence dating. Methods of annual dose detemination used by author are dating. Methods of annual dose determination used by author are summed up, and the results of different methods are compared. The emanium escapiug of three radioactive decay serieses in nature has been considered, and several determination methods are described. The contribution of cosmic rays for the annual radiation dose has been mentioned

Annual radiation dose in thermoluminescence dating

Energy Technology Data Exchange (ETDEWEB)

Huhou, Li [Chinese Academy of Social Sciences, Beijing, BJ (China). Inst. of Archaeology

1988-11-01

The annual radiation dose in thermoluminescence dating has been discussed. The autor gives an entirely new concept of the enviromental radiation in the thermoluminescence dating. Methods of annual dose detemination used by author are dating. Methods of annual dose determination used by author are summed up, and the results of different methods are compared. The emanium escapiug of three radioactive decay serieses in nature has been considered, and several determination methods are described. The contribution of cosmic rays for the annual radiation dose has been mentioned.

Stochastic chemical kinetics theory and (mostly) systems biological applications

CERN Document Server

Érdi, Péter; Lente, Gabor

2014-01-01

This volume reviews the theory and simulation methods of stochastic kinetics by integrating historical and recent perspectives, presents applications, mostly in the context of systems biology and also in combustion theory. In recent years, due to the development in experimental techniques, such as optical imaging, single cell analysis, and fluorescence spectroscopy, biochemical kinetic data inside single living cells have increasingly been available. The emergence of systems biology brought renaissance in the application of stochastic kinetic methods.

Thermo-luminescent dosimetry

Energy Technology Data Exchange (ETDEWEB)

Reither, M; Schorn, B; Schneider, E

1981-01-01

The development of paediatric radiology which began in the late 195O's has been characterised by the need to limit the dose of ionising radiation to which the child is subjected. The aim has been to keep radiation exposure as low as possible by the introduction of suitable techniques and by the development of new methods. It is therefore surprising that studies in dosimetry in the paediaytric age range have only been carried out in recent years. One reason for this may have been the fact that a suitable technique of measurement was not available at the time. The introduction of solid state dosimetry based on thermo-luminescence, first into radiotherapy (1968) and subsequently into radiodiagnosis, has made it possible to abandon the previously widely used ionisation chamber. The purpose of the present paper is to indicate the suitability of this form of dose measurement for paediatric radiological purposes and to stimulate its application in this field.

Thermal and radiation history of meteorites as revealed by their thermoluminescence records

International Nuclear Information System (INIS)

Bhandari, N.

1985-01-01

Attempts are described to derive information about important parameters of the thermal and radiation history of meteorites from a study of depth profile of thermoluminescence coupled to appropriate annealing studies. In this review some possibilities are examined, emphasizing various factors cardinal to any meaningful application of TL in meteoritics. (author)

Personnel monitoring of radiations with thermoluminescent dosemeters

International Nuclear Information System (INIS)

Miano, S.C.

1987-01-01

The basics of personnel dosimetry technics, used by the Radiologic Protetion and Assessorie Service (SAPRA) are presented, consisting on use of thermoluminescent and CaSO 4 :Dy monitors in aggregated pellets by Teflon. The characteristics of this dosemeters, relating to the sensitivity, energetic dependence, spike temperature, characteristic emission curve, decay and light effect are shown. The thermoluminescent dosemeter measure system and the personnel monitoring system are also described. (C.G.C.) [pt

Investigation of the characteristics of thermoluminescence glow curves of natural hydrothermal quartz from Hakkari area in Turkey

International Nuclear Information System (INIS)

Topaksu, M.; Yüksel, M.; Dogan, T.; Nur, N.; Akkaya, R.; Yegingil, Z.; Topak, Y.

2013-01-01

In this study the dosimetric characteristics of some natural hydrothermal quartz (NHQ) samples collected from Hakkari were investigated by using the thermoluminescence (TL) technique for the purpose of determining whether they are suitable as dosimetric materials or not and calculating the kinetic parameters. The experiments carried out can be outlined as: analyzing TL glow curves of NHQ; determining the annealing conditions; the effects of pre-irradiation annealing procedures on TL sensitivity; the investigation of the characteristics of TL glow curves obtained after annealing the samples; determination of the trap parameters with the computerized glow curve deconvolution (CGCD) method and the peak shape (PS) method. The obtained results showed that the trap depths and the frequency factor values are consistent with the literature. The studied samples have linear dose responses for the absorbed doses ranging between ∼6.689 Gy and ∼301 Gy. In conclusion, the examined quartz samples can be used as dosimetric materials in high dose applications

Thermoluminescent behavior of diamond thin films exposed to ultraviolet radiation

International Nuclear Information System (INIS)

Barboza F, M.; Gastelum, S.; Melendrez, R.; Chernov, V.; Bernal, R.; Cruz V, C.; Brown, F.

2002-01-01

In this work the thermoluminescent properties of diamond thin films are discussed which are grown up through the chemical vapor method exposed to ultraviolet radiation of 200-280 nm. The films with thickness 3, 6, 9, 12, 180 and 500 microns were grown up using a precursor gas formed of H 2 -CH 4 -CO excited through microwave energy or hot filament.The structure and morphology of the films were examined through scanning electron microscopy, indicating the formation of different diamond polycrystal structures which depend on the type of heating of the precursor gas used as well as the film dimensions. In general, the brilliance curve depends on the sample and the wavelength of the irradiation ultraviolet light, however it presents clearly thermoluminescence bands in 148, 160, 272, 304, 320 and 324 C degrees. The maximum of the thermoluminescence efficiency is obtained for the case of sample exposure with light of 214 nm. The sample of 500 microns is what exhibits greater thermoluminescent efficiency of those studied samples. The thermoluminescent behavior in function of radiation dose presents regions of linearity and supra linearity for higher and small doses respectively. The disappearance of the thermoluminescent signal depends on the characteristics of the film and it can reach until a 30 % of loss before to reach the stability. (Author)

Neutron dosimetry using activation of thermoluminescent CaSO 4

Science.gov (United States)

Azorín, Juan; Gutiérrez, Alicia

1984-11-01

Sulfur activation in calcium sulfate doped with dysprosium (CaSO 4:Dy) thermoluminescent powder, which is bound in pure sulfur, has been used to measure the fast neutron dose at the tangential beam port of a Triga Mark III reactor. After a post-irradiation time of 3 d, the dosimeters were annealed at 600°C for 30 min in order to erase all the thermoluminescence acquired during the irradiation. The dosimeters were then stored to allow self-irradiation by betas from 32P produced by sulfur activation. The thermoluminescent signal accumulated during a post-irradiation time of 20 d due to a neutron fluence of 2.2 × 10 11 n/cm 2 was equivalent to an absorbed dose of 10 mGy of 60Co gamma rays. The thermoluminescence as a function of fast neutron dose fitted to a straight line on a log-log scale from 1 Gy to 10 4Gy.

Thermoluminescence of novel MgO–CeO_2 obtained by a glycine-based solution combustion method

International Nuclear Information System (INIS)

Barrón, Victor Ramón Orante; Ochoa, Flor María Escobar; Vázquez, Catalina Cruz; Bernal, Rodolfo

2016-01-01

Thermoluminescence dosimetry properties of novel MgO–CeO_2 obtained by solution combustion synthesis in a glycine-nitrate process, are presented for the very first time. X-ray diffraction indicates the presence of cubic MgO and cerianite (CeO_2) for the annealed powder samples. Dosimetry features such as linear behaviour of the dose response without saturation in the dose interval studied, as well as asymptotic behaviour of the thermoluminescent signal fading place MgO–CeO_2 phosphor as a promising material for low-dose radiation dosimetry applications. - Highlights: • Thermoluminescence (TL) dosimetry properties of novel MgO–CeO_2 are presented. • TL glow curves display stable and dosimetric components. • Dose response showed a linear trend in the dose interval studied. • TL fading decay curve showed an asymptotic behaviour. • MgO–CeO_2 is suitable for personal, environmental and medical dosimetry.

Main Achievements 2003-2004 - Interdisciplinary Research - Radiation detection methods for health, earth and environmental sciences - Thermoluminescence (TL) detectors

International Nuclear Information System (INIS)

2005-01-01

The IFJ has over 35 years of experience in the development, production and application of new types of thermoluminescence (TL) detectors, particularly LiF:Mg,Ti and LiF:Mg,Cu,P. Over 600,000 LiF detectors produced at the IFJ PAN are routinely applied in dosimetry services and hospitals in 30 countries. The current research in the field of thermoluminescence concentrates in space dosimetry and novel 2-dimensional detectors for medical applications. The space project (named Matroshka), organized by the European Space Agency, is one of the most ambitious dosimetry experiments in space. In February 2004 an anatomical model of the human body (a humanoid phantom), equipped with over 3500 dedicated thermoluminescent detectors (TLD), developed and produced at IFJ and tested at the Chiba heavy ion accelerator in Japan, was installed outside the International Space Station (ISS) to determine the cosmic radiation doses absorbed in human organs, which would be experienced by astronauts in open space. The phantom will remain in space for one year, after which the detectors will be returned to the IFJ for analysis

Kerma determination in air on mamma by thermoluminescence

International Nuclear Information System (INIS)

Palacios P, L. L.; Rivera M, T.

2009-10-01

In this work the experimental results of the entrance exposition are shown and Kerma in air [mGy] in mamma obtained by irradiation of accreditation phantom of American College of Radiology (ACR). The irradiations were realized in a conventional mammography equipment of Hospital Juarez in Mexico; the technique used during the irradiations was of automatic exposition; the thickness for the phantom ACR obtained by the technique were of 4.2 and 4.5 cm; the kilo voltage pick was of 24 kV p , the time and the milli amperage per second variable. The measuring of Kerma in air was obtained with thermoluminescent dosemeters of solid state, of nano particles of zirconium dioxide prepared by the precipitation method. The dosemeters were homogenized previously in low energies of X-rays that are those used for mammography. The thermoluminescent dosemeters of ZrO 2 were calibrated by means of an ionization chamber for different expositions. The calibration curve is reported for the exposition and Kerma in air against thermoluminescent intensity obtained by reading of thermoluminescent dosemeters of ZrO 2 , as well as the technique employee for the Kerma determination in air and entrance exposition in mamma. (Author)

Thermoluminescence of magnesium oxide and its trapping kinetics

Energy Technology Data Exchange (ETDEWEB)

Nagpal, J.S. (Bhabha Atomic Research Centre, Bombay (India). Div. of Radiological Protection); Kathuria, S.P. (Bhabha Atomic Research Centre, Bombay (India). Health Physics Div.)

1984-06-01

MgO (Norton), on u.v. and ..gamma.. irradiation, exhibits TL glow peaks around 88, 150, 172, 195 and 250degC (heating rate 55degC min/sup -1/). TL emission is observed around 340, 390, 445 and 705 nm and can be attributed to the impurities Fe/sup 3 +/ and Cr/sup 3 +/, which act as luminescence centers. ESR studies rule out any participation of Mn/sup 2 +/ ions. The glow peak around 88degC has E = 1.055 eV, s = 4.3 x 10/sup 13/s/sup -1/ and has order of kinetics b = 1.7.

Thermoluminescence of magnesium oxide and its trapping kinetics

International Nuclear Information System (INIS)

Nagpal, J.S.; Kathuria, S.P.

1984-01-01

MgO (Norton), on u.v. and γ irradiation, exhibits TL glow peaks around 88, 150, 172, 195 and 250degC (heating rate 55degC min -1 ). TL emission is observed around 340, 390, 445 and 705 nm and can be attributed to the impurities Fe 3+ and Cr 3+ , which act as luminescence centers. ESR studies rule out any participation of Mn 2+ ions. The glow peak around 88degC has E = 1.055 eV, s = 4.3 x 10 13 s -1 and has order of kinetics b = 1.7. (author)

Thermoluminescent properties of nanocrystalline ZnTe thin films: Structural and morphological studies

Science.gov (United States)

Rajpal, Shashikant; Kumar, S. R.

2018-04-01

Zinc Telluride (ZnTe) is a binary II-VI direct band gap semiconducting material with cubic structure and having potential applications in different opto-electronic devices. Here we investigated the effects of annealing on the thermoluminescence (TL) of ZnTe thin films. A nanocrystalline ZnTe thin film was successfully electrodeposited on nickel substrate and the effect of annealing on structural, morphological, and optical properties were studied. The TL emission spectrum of as deposited sample is weakly emissive in UV region at ∼328 nm. The variation in the annealing temperature results into sharp increase in emission intensity at ∼328 nm along with appearance of a new peak at ∼437 nm in visible region. Thus, the deposited nanocrystalline ZnTe thin films exhibited excellent thermoluminescent properties upon annealing. Furthermore, the influence of annealing (annealed at 400 °C) on the solid state of ZnTe were also studied by XRD, SEM, EDS, AFM. It is observed that ZnTe thin film annealed at 400 °C after deposition provide a smooth and flat texture suited for optoelectronic applications.

Authenticity test in ceramics and archaeological figures by thermoluminescence

International Nuclear Information System (INIS)

Ramirez L, A.; Schaaf, P.; Filloy, L.

1999-01-01

At present exists quite a lot of false archaeological pieces which provokes doubts about the legitimacy of the pieces. In this work it is presented the Authenticity test by Thermoluminescence realized at the urn of the goddess 13 serpent of the zapotec culture of Oaxaca which is exposed in Mexico City. The original piece contains crystalline structures which present hardly the thermoluminescence phenomena by the presence of 238 U, 232 Th, and 40 K getting with this the form and intensity of the natural thermoluminescence curve of an archaeological piece which shows a Tl peak and allows to know so if it was made recently or not. (Author)

An evaluation of the Panasonic model UD513AC-1 Thermoluminescence Dosimetry system

International Nuclear Information System (INIS)

Durrer, R.E. Jr.

1991-12-01

An evaluation of the Panasonic UD513AC-1 Thermoluminescence Dosimetry system was performed to determine the system's capabilities as a general purpose thermoluminescence dosimeter measuring device. The tests that were performed included a critique of the user's manual, delimitation of the operating parameters, the quality of construction, and an evaluation of the features that were unique to this system. The UD513AC-1 was found to be an adequate measuring device for most dosimetric applications. It was not well suited for experimental work with thermoluminescence materials due to a low sensitivity displayed by the photomultiplier tube to commonly used materials. The system was well constructed and did not suffer hardware failure during this research. Major attributes of the UD513AC-1 were automatic data storage, highly reproducible heating ramps, an excellent infrared light filter and a unique feature to a single phosphor unit, a dose determination function. Negative aspects of the system included a limited data manipulation capability within the controlling program, a poorly written user's manual, inadequate sensitivity on the part of the photomultiplier tube, and insufficient capability to adjust the hot N 2 gas flow to desired levels

Characterization of the chlorophyll thermoluminescence afterglow in dark-adapted or far-red-illuminated plant leaves

International Nuclear Information System (INIS)

Miranda, T.; Ducruet, J.M.

1995-01-01

Far red illumination of photosynthetic material induces a delayed luminescence rise, or afterglow, which has been reported in plant leaves, protoplasts or intact chloroplasts and in algal cells. but does not occur in isolated thylakoids. The rise kinetics is accelerated by increasing temperature and we show, by slowly heating a leaf sample after a far-red illumination, that the afterglow emission can be optimally resolved as a sharp thermoluminescence band. Plant material was mainly pea (Pisum sativum L., cv Kazar and Merveille de Kelvedon) and cucumber (Cucumis sativus L., cv Marketer). Comparisons were done with rape, spinach, tobacco, avocado and maize. A 0.2 degree C-1s to 0.5 degree C-1s temperature gradient, started above 0 degree C after a far red illumination, revealed a new thermoluminescence AG band, peaking between 40 degree C and 50 degree C. It exhibited the characteristic properties of the luminescence afterglow recorded at a constant temperature. The AG band was very sensitive to short incubations at both freezing and moderately warm temperatures. Increasing duration of far red illumination caused two kinetically distinct effects on the AG band and on the B band (S-2S-3 Q-B- recombination), which can be ascribed to different behaviors of proton gradients in stroma and in grana lamellae, respectively. The induction of an afterglow by far red light lasted for several minutes in the dark, at 10 degree C. Flash sequences fired in these conditions confirmed the presence of S-2 and S-3 states stable in the dark, producing luminescence by recombination with back-transferred electrons. In some plant batches, an AG band could be induced by 2 or 3 flashes in the absence of far red light, which demonstrates that a metabolic state leading to AG emission may arise spontaneously in plant leaves. The strong temperature dependence of the AG emission is discussed in terms of heat-induced conformational changes in the thylakoid membrane. We conclude that

Thermoluminescent dosimetric properties of Descalvado sand

International Nuclear Information System (INIS)

Teixeira, M.I.; Caldas, L.V.E.

2006-01-01

Sand samples proceeding from Descalvado, Sao Paulo, were studied with regard to their dosimetric properties using the thermoluminescence technique (TL) for high doses. These sand samples present steady physical and chemical characteristics to the end items, and they are used in the glass industry and for casting. The TL curves of the samples were obtained after an irradiation at the Gamma-Cell system ( 60 Co), of IPEN. The glow curves present two peaks at 80 C and 220 C approximately. Calibration curves were obtained for doses between 50 Gy and 5 kGy. The results indicate that the sand samples can be used for high-doses dosimetry in several areas of applications of ionizing radiation. (Author)

Thermoluminescent dosimetric properties of Descalvado sand

Energy Technology Data Exchange (ETDEWEB)

Teixeira, M.I.; Caldas, L.V.E

2006-07-01

Sand samples proceeding from Descalvado, Sao Paulo, were studied with regard to their dosimetric properties using the thermoluminescence technique (TL) for high doses. These sand samples present steady physical and chemical characteristics to the end items, and they are used in the glass industry and for casting. The TL curves of the samples were obtained after an irradiation at the Gamma-Cell system ({sup 60} Co), of IPEN. The glow curves present two peaks at 80 C and 220 C approximately. Calibration curves were obtained for doses between 50 Gy and 5 kGy. The results indicate that the sand samples can be used for high-doses dosimetry in several areas of applications of ionizing radiation. (Author)

Thermoluminescence of LiF: Mg, Ti between 77 and 315 K

International Nuclear Information System (INIS)

Rosa, L.A.R. da.

1989-01-01

A special thermoluminescent system was developed. It is able to operate right from liquid nitrogen temperature and also permits the determination of the sample thermoluminescent emission spectrum. Using this system, the thermoluminescence displayed by 77 K irradiated LiF:Mg,Ti (TLD-100), from the irradiation temperature to 315 K, was studied. In this temperature range seven glow peaks, at 139, 153, 194, 240, 260, 283 and 300 K, were determined. (author)

Fit of second order thermoluminescence glow peaks using the logistic distribution function

International Nuclear Information System (INIS)

Pagonis, V.; Kitis, G.

2001-01-01

A new thermoluminescence glow curve deconvolution (GCD) function is introduced which accurately describes second order thermoluminescence (TL) curves. The logistic asymmetric (LA) statistical probability function is used with the function variables being the maximum peak intensity (I m ), the temperature of the maximum peak intensity (T m ) and the LA width parameter a 2 . An analytical expression is derived from which the activation energy E can be calculated as a function of T m and the LA width parameter a 2 with an accuracy of 2% or better. The accuracy of the fit was tested for E values ranging from 0.7 to 2.5 eV, for s values between 10 5 and 10 25 s -1 , and for trap occupation number n 0 /N between 1 and 10 -6 . The goodness of fit of the logistic asymmetric function is described by the Figure of Merit (FOM) which is found to be of the order of 10 -2 . Preliminary results show that the GCD described here can easily be extended to the description of general order TL glow curves by varying the asymmetry parameter of the logistic asymmetric function. It is concluded that the TL kinetic analysis of first, second and general order TL glow curves can be performed with high accuracy and speed by using commercially available statistical packages that incorporate the Weibull and logistic asymmetric functions. (author)

Thermoluminescence dosimetry materials: properties and uses

International Nuclear Information System (INIS)

McKeever, S.W.S.; Moscovitch, M.; Townsend, P.D.

1995-01-01

This book selects a range of the most popular thermoluminescence dosemeter (TLD) materials in use today and provides a critical account of their thermoluminescence (TL) and dosimetric properties. The information provided includes in-depth discussions of TL mechanisms, including an account of luminescence properties, and relevant information regarding dosimetric characteristics. The book is intended for those involved in TLD materials research, and for technicians and workers involved in the practical application of these materials in TL dosimetry. The advent of modern spectroscopic methods for measuring TL emission spectra (the so-called ''3-D'' presentation) seemed to the authors to be an invitation to compile such spectra for all the major TLD materials. Further consideration led to an expansion of the initial idea to include a compilation of dosimetric properties. One intention is to provide a synopsis of the TL and dosimetric properties of the most widely used TLD materials currently available and to form a link between the solid state defect properties of these materials and their actual dosimetric properties. A second intention is to provide a solid framework from which future studies of TLD materials could be launched. Too often in the past research into TLD materials has been haphazard, to say the least. By illustrating the links between solid state physics and the radiation dosimetry properties of these materials the book points to the future and to the pressing need for enhanced research on TLD materials. (Author)

The thermoluminescent curve as parameter to compare archaeological ceramics

International Nuclear Information System (INIS)

Dominguez R, I.R.; Ramirez C, G.A.; Gonzalez M, P.R.; Mendoza A, D.; Martinez C, G.

2006-01-01

Most mineral materials, including the constituents of pottery, have the property of thermoluminescence (TL), where part of the energy from radioactive decay in the mineral is stored and later released as light upon strong heating. The intensity of emitted light as a function of temperature is the thermoluminescence glow curve. However, it is well-know the thermoluminescence glow curve form depends of several factors associates with the incident radiation and type of materials. Between the factors associated with the materials, it can be mentioned the quantity and type of crystalline phases, and quantity and type of impurities that they could be present in the material. That is to say, materials with different physicochemical characteristics will produce different thermoluminescence glow curve, although, they have been irradiated under the same conditions. In accordance with the above mentioned, it is possible to identified differences between pre hispanic ceramic belonging to a same site and other sites. In this work a discussion about advantages and disadvantages is presented. Some specific examples in ceramic artifacts belonging to the Matlatzinca and Teotihuacan cultures are included. (Author)

Thermoluminescence response and glow curve structure of Sc2TiO5 ß-irradiated

International Nuclear Information System (INIS)

Muñoz, I.C.; Brown, F.; Durán-Muñoz, H.; Cruz-Zaragoza, E.; Durán-Torres, B.; Alvarez-Montaño, V.E.

2014-01-01

Discandium titanate (Sc 2 TiO 5 ) powder was synthesized in order to analyze its thermoluminescence (TL) response. The TL glow curve structure shows two peaks: at 453–433 K and at 590–553 K. The TL beta dose–response has a linear behavior over the dose range 50–500 Gy. The T stop preheat method shows five glow peaks that were taken into account to calculate the kinetic parameters using the CGCD procedure. TL results support the possible use of Sc 2 TiO 5 as a new phosphor in high ß-dose dosimetry. - Highlights: • Discandium titanate was synthesized, and its TL properties were analyzed. • The beta dose–response has a linear behavior on the dose range 50–500 Gy. • The kinetic parameters were obtained by the CGCD procedure. • Results support the possible use of Sc 2 TiO 5 as a new phosphor for ß-dose dosimetry

Comparison of thermoluminescence detection methods for irradiated spices

International Nuclear Information System (INIS)

Kawamura, Y.; Murayama, M.; Uchiyama, S.; Saito, Y.

1996-01-01

Thermoluminescence (TL) analysis has been shown to be one of the most applicable methods for the detection of γ-irradiated spices. This analysis was introduced as a detection technique for irradiated spices using the whole sample. It was then found that the origin of the TL response to be mineral dust adhering to the spices. TL measurements on separated minerals and the normalised TL measurement by re-irradiation was then established. This paper details investigations on TL measurements carried out using clean powdered spices stored for one year after being irradiated with doses of 1, 5, 10 and 30 kGy in order to clarify their applicable dose range, the effect of storage and mineral content. The effect of the mineral separation was also studied. (author)

A study of the high-temperature signal characteristics in the thermoluminescence of porcelain

International Nuclear Information System (INIS)

Yin Gongming

2001-01-01

The thermoluminescence pre-dose technique for dating ancient porcelain was developed in many laboratories. This technique was the only method which could directly determine the age of old porcelain. But the thermoluminescence high-temperature signal (over 200 degree C) had not been studied. The authors conduced a preliminary study of the characteristic of thermoluminescence high-temperature signal, such as the TL natural glow curve, and the glow curves after beta or alpha irradiation. Most of the 32 ancient porcelains had thermoluminescence high temperature signal, and only one peak in their TL glow curve was found

Application of Extreme Learning Machines to inverse neutron kinetics

International Nuclear Information System (INIS)

Picca, Paolo; Furfaro, Roberto

2017-01-01

Highlights: • The paper applies the Extreme Learning Machines (ELMs) to inverse reactor problems. • Multi-group transport model is used for the inversion as opposed to point kinetics. • ELMs are compared against Artificial Neural Networks (ANNs). • Various options are tested to improve the reliability of the estimation. • Results highlight the potential of the ELM approach. - Abstract: The paper presents the application of Extreme Leaning Machines (ELMs) for inverse reactor kinetic applications. ELMs were proposed by Huang and co-workers (2004, 2006a,b, 2015), which showed their enhances capabilities in terms of training speed and generalization with respect to classical Artificial Neural Networks (ANNs). ELMs are here implemented for reactivity determination as an alternative to ANNs (e.g. Picca et al. (2008)) and Gaussian Processes (Picca and Furfaro, 2012). After a review of the main features of ELMs, their application to inverse kinetic problems is proposed. The ELMs performance is tested on a typical accelerator drive system configuration (Yalina reactor) and the inversion is carried out on an accurate kinetic model (multi-group transport).

Thermoluminescence of zirconium oxide nanostructured to mammography X-ray beams

International Nuclear Information System (INIS)

Palacios, L.L.; Rivera, T.; Roman, J.; Azorín, J.; Gaona, E.

2012-01-01

In the present work thermoluminescent (TL) response of zirconium oxide (ZrO 2 ) nanostructured induced by mammography X-ray radiation was investigated. Measurements were made of the response per unit air kerma of ZrO 2 with mammography equipment parameters (semiautomatic exposure control, 24 kVp and 108 mAs). The calibration curves were obtained by simultaneously irradiating ZrO 2 samples and ion chamber. Samples of ZrO 2 showed a linear response as a function of entrance skin air kerma. The observed results in TL properties suggest that ZrO 2 nanostructured could be considered as an effective material for X-ray beams dosimetry if appropriate calibration procedures are performed. - Highlights: ► X-ray low energy thermoluminescent of ZrO 2 dosimeter is developed. ► Air kerma measurements were made by thermoluminescent dosimeter ZrO 2 using mammography equipment parameters. ► Entrance surface skin doses were made using thermoluminescent dosimeter of ZrO 2 to X-ray beam quality control.

Thermoluminescence dosimetry in Northwest Puerto Rico

International Nuclear Information System (INIS)

Block, A.M.; Clements, R.G.; Rosa, L.I.; Santos, F.

1975-01-01

In October, 1973, the Puerto Rico Water Resources Authority sought the initiation of studies aimed at determining background radiological characteristics of the northwestern quadrant of Puerto Rico using thermoluminescent dosemeters. Some of the studies were required for supporting data for the environmental report submitted as part of the licensing procedure in the establishment of thermonuclear electric power generation facilities in Barrio Islote, Arecibo, Puerto Rico. Previous studies of radiological characteristics of the area had been made using sodium iodide sensing equipment in an airplane flying at an altitude of 500 ft. The results are expressed in counts per second, and provide useful comparative levels for radioactivity measured with the thermoluminescent detectors. (U.S.)

Relativistic kinetic theory with applications in astrophysics and cosmology

CERN Document Server

Vereshchagin, Gregory V

2017-01-01

Relativistic kinetic theory has widespread application in astrophysics and cosmology. The interest has grown in recent years as experimentalists are now able to make reliable measurements on physical systems where relativistic effects are no longer negligible. This ambitious monograph is divided into three parts. It presents the basic ideas and concepts of this theory, equations and methods, including derivation of kinetic equations from the relativistic BBGKY hierarchy and discussion of the relation between kinetic and hydrodynamic levels of description. The second part introduces elements of computational physics with special emphasis on numerical integration of Boltzmann equations and related approaches, as well as multi-component hydrodynamics. The third part presents an overview of applications ranging from covariant theory of plasma response, thermalization of relativistic plasma, comptonization in static and moving media to kinetics of self-gravitating systems, cosmological structure formation and neut...

Thermoluminescence method for detection of irradiated food

International Nuclear Information System (INIS)

Pinnioja, S.

1998-01-01

A method of thermoluminescence (TL) analysis was developed for the detection of irradiated foods. The TL method is based on the determination of thermoluminescence of adhering or contaminating minerals separated from foods by wet sieving and treatment with high density liquid. Carbon tetrachloride provided a suitable alternative for foods that form gels with water. Thermoluminescence response of minerals in a first TL measurement is normalised with a second TL measurement of the same mineral sample after calibration irradiation to a dose of 5 kGy. The decision about irradiation is made on the basis of a comparison of the two TL spectra: if the two TL glow curves match in shape and intensity the sample has been irradiated, and if they are clearly different it has not been irradiated. An attractive feature of TL analysis is that the mineral material itself is used for calibration; no reference material is required. Foods of interest in the investigation were herbs, spices, berries and seafood. The presence of minerals in samples is a criterion for application of the method, and appropriate minerals were found in all herbs, spices and berries. The most common minerals in terrestrial food were tecto-silicates - quartz and feldspars - which with their intense and stable thermoluminescence were well suited for the analysis. Mica proved to be useless for detection purposes, whereas carbonate in the form of calcite separated from intestines of seafood was acceptable. Fading of the TL signal is considerable in the low temperature part of the glow curve during a storage of several months after irradiation. However, spices and herbs could easily be identified as irradiated even after two years storage. Conditions for seafood, which is stored in a freezer, are different, and only slight fading was observed after one year. The effect of mineral composition and structure on TL was studied for feldspars. Feldspars originating from subtropical and tropical regions exhibit lower TL

Thermoluminescence method for detection of irradiated food

Energy Technology Data Exchange (ETDEWEB)

Pinnioja, S

1998-12-31

A method of thermoluminescence (TL) analysis was developed for the detection of irradiated foods. The TL method is based on the determination of thermoluminescence of adhering or contaminating minerals separated from foods by wet sieving and treatment with high density liquid. Carbon tetrachloride provided a suitable alternative for foods that form gels with water. Thermoluminescence response of minerals in a first TL measurement is normalised with a second TL measurement of the same mineral sample after calibration irradiation to a dose of 5 kGy. The decision about irradiation is made on the basis of a comparison of the two TL spectra: if the two TL glow curves match in shape and intensity the sample has been irradiated, and if they are clearly different it has not been irradiated. An attractive feature of TL analysis is that the mineral material itself is used for calibration; no reference material is required. Foods of interest in the investigation were herbs, spices, berries and seafood. The presence of minerals in samples is a criterion for application of the method, and appropriate minerals were found in all herbs, spices and berries. The most common minerals in terrestrial food were tecto-silicates - quartz and feldspars - which with their intense and stable thermoluminescence were well suited for the analysis. Mica proved to be useless for detection purposes, whereas carbonate in the form of calcite separated from intestines of seafood was acceptable. Fading of the TL signal is considerable in the low temperature part of the glow curve during a storage of several months after irradiation. However, spices and herbs could easily be identified as irradiated even after two years storage. Conditions for seafood, which is stored in a freezer, are different, and only slight fading was observed after one year. The effect of mineral composition and structure on TL was studied for feldspars. Feldspars originating from subtropical and tropical regions exhibit lower TL

The initial rise method extended to multiple trapping levels in thermoluminescent materials

Energy Technology Data Exchange (ETDEWEB)

Furetta, C. [CICATA-Legaria, Instituto Politecnico Nacional, 11500 Mexico D.F. (Mexico); Guzman, S. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, A.P. 70-543, 04510 Mexico D.F. (Mexico); Ruiz, B. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, A.P. 70-543, 04510 Mexico D.F. (Mexico); Departamento de Agricultura y Ganaderia, Universidad de Sonora, A.P. 305, 83190 Hermosillo, Sonora (Mexico); Cruz-Zaragoza, E., E-mail: ecruz@nucleares.unam.m [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, A.P. 70-543, 04510 Mexico D.F. (Mexico)

2011-02-15

The well known Initial Rise Method (IR) is commonly used to determine the activation energy when only one glow peak is presented and analysed in the phosphor materials. However, when the glow peak is more complex, a wide peak and some holders appear in the structure. The application of the Initial Rise Method is not valid because multiple trapping levels are considered and then the thermoluminescent analysis becomes difficult to perform. This paper shows the case of a complex glow curve structure as an example and shows that the calculation is also possible using the IR method. The aim of the paper is to extend the well known Initial Rise Method (IR) to the case of multiple trapping levels. The IR method is applied to minerals extracted from Nopal cactus and Oregano spices because the thermoluminescent glow curve's shape suggests a trap distribution instead of a single trapping level.

The initial rise method extended to multiple trapping levels in thermoluminescent materials

International Nuclear Information System (INIS)

Furetta, C.; Guzman, S.; Ruiz, B.; Cruz-Zaragoza, E.

2011-01-01

The well known Initial Rise Method (IR) is commonly used to determine the activation energy when only one glow peak is presented and analysed in the phosphor materials. However, when the glow peak is more complex, a wide peak and some holders appear in the structure. The application of the Initial Rise Method is not valid because multiple trapping levels are considered and then the thermoluminescent analysis becomes difficult to perform. This paper shows the case of a complex glow curve structure as an example and shows that the calculation is also possible using the IR method. The aim of the paper is to extend the well known Initial Rise Method (IR) to the case of multiple trapping levels. The IR method is applied to minerals extracted from Nopal cactus and Oregano spices because the thermoluminescent glow curve's shape suggests a trap distribution instead of a single trapping level.

Dose measurements in dental radiology using thermoluminescent dosimetry

International Nuclear Information System (INIS)

Chiara, Ana Claudia M. de; Costa, Alessandro M.; Pardini, Luiz Carlos

2009-01-01

The aim of this work was the implementation of a code of practice for dosimetry in dental radiology using the technique of thermoluminescent dosimetry. General principles for the use of thermoluminescent dosimeters were followed. The irradiations were performed using ten X-ray equipment for intra-oral radiography and an X-ray equipment for panoramic radiography. The incident air kerma was evaluated for five different exposure times used in clinical practice for intra-oral radiographs. Using a backscatter factor of 1.2, it was observed that approximately 40% of the entrance skin dose values found for intra-oral radiographs are above the diagnostic reference level recommended in national regulation. Different configurations of voltage and current were used representing the exposure as a child, woman and man for panoramic radiographs. The results obtained for the air kerma area product were respectively 53.3 +- 5.2 mGy.cm 2 , 101.5 +- 9.5 mGy.cm 2 and 116.8 +- 10.4 mGy.cm 2 . The use of thermoluminescent dosimetry requires several procedures before a result is recorded. The use of dosimeters with ionization chambers or semiconductors provides a simple and robust method for routine measurements. However, the use of thermoluminescent dosimetry can be of great value to large-scale surveys to establish diagnostic reference levels. (author)

Thermoluminescence of cerium and terbium -doped calcium pyrophosphate

Energy Technology Data Exchange (ETDEWEB)

Roman L, J.; Cruz Z, E. [UNAM, Instituto de Ciencias Nucleares, Circuito Exterior, Ciudad Universitaria, 04510 Mexico D. F. (Mexico); Lozano R, I. B.; Diaz G, J. A. I., E-mail: jesus.roman@nucleares.unam.mx [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Av. Legaria No. 694, 11500 Mexico D. F. (Mexico)

2015-10-15

The aim of this work is to report the thermoluminescence (Tl) response of Calcium Pyrophosphate phosphor doped with Cerium and Terbium impurities (Ca{sub 2}P{sub 2}O{sub 7}:Ce{sup 3+},Tb{sup 3+}). The phosphors were synthesized using the co-precipitation method and annealed at 900 degrees C by two hours for obtain the β phase. The intentional doping with Ce and Tb ions was 1 at.% and 0.1 at.%, whereas in the EDS results the concentration of impurities was 0.39 at.% and 0.05 at.%, respectively. The superficial morphology of phosphor is mainly composed by thin wafers of different size. All samples were exposed to gamma rays from {sup 60}Co in the Gammacell-200 irradiator. The Tl response of the phosphor was measured from Rt up to 350 degrees C and under nitrogen atmosphere in a Harshaw TLD 3500 reader. The glow curves of the Ca{sub 2}P{sub 2}O{sub 7}:Ce{sup 3+},Tb{sup 3+} powders showed a broad intense Tl peak centered at 165 degrees C and a shoulder at approximate 260 degrees C was observed. A linear Tl response in the range of absorbed dose of 0.2 to 10 Gy was obtained. Tl glow curves were analyzed using the initial rise (IR)and computerized glow curve deconvolution methods to evaluate the kinetics parameters such as activation energy (E), frequency factor (s) and kinetic order (b). (Author)

Obtention of a thermoluminescent material for dosimetry of ionizing radiation

International Nuclear Information System (INIS)

Gonzalez M, P.R.

1990-01-01

The thermoluminescent dosemeters are small crystals which suffer changes in their structure by the radiation effect, being displaced the electrons toward higher energy levels. On heating the previously irradiated crystals, the electrons come back to their base state emitting light photons. The light quantity emitted is proportional to the received radiation dose. The light quantity emitted is proportional to the received radiation dose. The lithium fluoride is one of the thermoluminescent materials considered as tissue equivalents by having a low effective atomic number (Z ef ). At present, the more used commercial product used of this type is the TLD-100*. In this work the obtained results in the preparation of the lithium fluoride thermoluminescent material are presented. This is activated with magnesium (Mg) and titanium (Ti), which we have labelled as: LiF: Mg, Ti. The results from the tests performed for verifying his thermoluminescent properties are presented too, as powder form as in pellets form. These tests were performed in simultaneous form with TLD-100 samples, which is considered as reference. The LiF: Mg, Ti thermoluminescent material manufactured in the ININ presents similar dosimetric characteristics to those ones of the TLD-100. Therefore being able to replace the imported dosemeters. * (TLD-100 is a commercial trademark registered by Harshaw/Filtrol (US) for LiF: Mg, Ti Tl dosemeters) (Author)

Eu"2"+ doped TiO_2 nano structures synthesized by HYSYCVD for thermoluminescence dosimetry

International Nuclear Information System (INIS)

Perez A, J. A.; Leal C, A. L.; Melendrez A, R.; Barboza F, M.

2016-10-01

Titania (TiO_2) has attracted interest owing his potential applications as dosimetry material given his excellent optical, electrical and thermal properties and the ability to shape his structure make TiO_2 suitable for research and dosimetry applications. In this work, a systematic study to know the magnitude of processing parameters influence on thermoluminescent properties of undoped (TiO_2) and doped (TiO_2:Eu"2"+) nano materials obtained by hybrid precursor systems chemical vapor deposition (HYSYCVD) technique is presented. Synthesis of one dimension nano structures of TiO_2:Eu"2"+ was carried out using K_2TiF_6 and EuCl_2 as dopant at 0.5, 1, 2.5 and 5 wt %. The nano structures samples were irradiated with β-ray in a doses range of 0.083-3000 Gy. All thermoluminescence (Tl) glow curves showed 3 broad Tl peaks around 373, 473 and 573 K, and a dosimetric linear behavior from 0.083 to 300 Gy. The Tl has a good reproducibility, with deviations of around 5%, making these TiO_2:Eu"2"+ nano materials suitable for dosimetric applications. (Author)

Kinetic simulations in plasmas: a general view and some applications

Energy Technology Data Exchange (ETDEWEB)

Alves, Maria Virginia [Instituto Nacional de Pesquisas Espaciais (INPE), Sao Jose dos Campos, SP (Brazil). Lab. Associado de Plasma]. E-mail: alves@plasma.inpe.br

1999-07-01

In these lecture notes we talk about kinetic simulations plasma physics. We present a general view of the different approach that can be given to kinetic plasmas depending on the physical problem to be investigated. Some applications of kinetic simulations to space plasma phenomena and Pierce electrodes are introduced. (author)

Kinetic simulations in plasmas: a general view and some applications

International Nuclear Information System (INIS)

Alves, Maria Virginia

1999-01-01

In these lecture notes we talk about kinetic simulations plasma physics. We present a general view of the different approach that can be given to kinetic plasmas depending on the physical problem to be investigated. Some applications of kinetic simulations to space plasma phenomena and Pierce electrodes are introduced. (author)

Thermoluminescent dosimetric properties of CaF{sub 2}:Tm produced by combustion synthesis

Energy Technology Data Exchange (ETDEWEB)

Vasconcelos, D.A.A. de; Khoury, H.J.; Asfora, V.K.; Barros, V.S.M. [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear; Oliveira, R.A.P. [Universidade Federal do Vale do Sao Francisco (IPCM/UNIVASF), Juazeiro, BA (Brazil). Instituto de Pesquisa em Ciencias dos Materiais. Departamento de Energia Nuclear

2015-07-01

Calcium Fluoride is one of the oldest known thermoluminescent materials and is considered to be one of the most sensitive. In particular for thulium doped CaF{sub 2}, since it was introduced in 1977 by Lucas and Kapsar, besides gamma radiation dosimetry, there have been several attempts for its use in application involving mixed radiation fields (ex.: neutron and gamma; alpha and beta), low energy photons, π- dosimetry and neutrino detection. Research for novel improved methods of fabrication are ongoing. This work presents the dosimetric properties results of CaF{sub 2}:Tm produced by combustion synthesis. The X-ray diffraction (Brucker D2 Phaser) confirmed that CaF{sub 2} was successfully produced. Samples were irradiated in a Co-60 (Gammacell 220 Nordion) and Cs-137 (STS/OB-85) gamma sources for high and low doses, respectively. TL emission spectra, obtained using a Hammamatsu optical spectrometer, has the same lines of commercial CaF{sub 2}:Tm, although transitions {sup 3}P{sub 0} → {sup 3}F{sub 4} (455 nm) and {sup 1}G{sub 4}→ {sup 3}H{sub 6} (482 nm) are shown to be proportionally more intense. The dose response lower limit is in the range of 100 μGy. Thermoluminescence glow curves were obtained in a Harshaw 3500 TL reader. The deconvolution technique was employed and seven glow peaks were found as well as its kinetic parameters, similar to the commercial CaF{sub 2}:Tm. A linear dose response curve was obtained for the range 0.1 mGy to 50 Gy, with the onset of a supralinear behavior at 50 Gy up to 100 Gy. The minimum measurable dose for gamma (Cs- 137) was around 100 μGy for a 6.0 mm diameter by 1.0 mm in thickness pellet. Variation of the dose response due to fading was within 6% in 60 days. (author)

Thermoluminescence of pure LiF and Lif (TLD-100) irradiated at room temperature

International Nuclear Information System (INIS)

Sagastibelza Chivite, F.

1980-01-01

The thermoluminescence of pure LiF and LiF (TLD-100) crystals irradiated at room temperature with x - or gamma-rays has been studied up to 460 degree centigree. For most of the glow peaks found the kinetics, preexponential factors and activation energies have been determined. These parameters have been obtained by means of the isothermal method. The study of the thermal annealing of the radiation induced F and Z centres has allow to show that there is a correlation among the glow peaks and the annealing stages of these centres. It is concluded that the F and Z - centres play the role of recombination centres for halogen interstitial atom thermally released from traps. Light emission occurs in this recombination. (Author) 120 refs

Instrumentation in thermoluminescence dosimetry

International Nuclear Information System (INIS)

Julius, H.W.

1986-01-01

In the performance of a thermoluminescence dosimetry (TLD) system the equipment plays an important role. Crucial parameters of instrumentation in TLD are discussed in some detail. A review is given of equipment available on the market today - with some emphasis on automation - which is partly based on information from industry and others involved in research and development. (author)

Thermoluminescence of zirconium oxide nanostructured to mammography X-ray beams

Energy Technology Data Exchange (ETDEWEB)

Palacios, L.L. [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada-Legaria, IPN. Av. Legaria 694, 11500 Mexico D.F. (Mexico); Rivera, T., E-mail: trivera@ipn.mx [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada-Legaria, IPN. Av. Legaria 694, 11500 Mexico D.F. (Mexico); Roman, J. [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada-Legaria, IPN. Av. Legaria 694, 11500 Mexico D.F. (Mexico); Azorin, J. [Universidad Autonoma Metropolitana-Iztapalapa. Av. San Rafael Atlixco 187, 09340 Mexico D.F. (Mexico); Gaona, E. [Universidad Autonoma Metropolitana-Xochimilco. Calz. Del Hueso 1100, 04960 Mexico D.F. (Mexico)

2012-07-15

In the present work thermoluminescent (TL) response of zirconium oxide (ZrO{sub 2}) nanostructured induced by mammography X-ray radiation was investigated. Measurements were made of the response per unit air kerma of ZrO{sub 2} with mammography equipment parameters (semiautomatic exposure control, 24 kVp and 108 mAs). The calibration curves were obtained by simultaneously irradiating ZrO{sub 2} samples and ion chamber. Samples of ZrO{sub 2} showed a linear response as a function of entrance skin air kerma. The observed results in TL properties suggest that ZrO{sub 2} nanostructured could be considered as an effective material for X-ray beams dosimetry if appropriate calibration procedures are performed. - Highlights: Black-Right-Pointing-Pointer X-ray low energy thermoluminescent of ZrO{sub 2} dosimeter is developed. Black-Right-Pointing-Pointer Air kerma measurements were made by thermoluminescent dosimeter ZrO{sub 2} using mammography equipment parameters. Black-Right-Pointing-Pointer Entrance surface skin doses were made using thermoluminescent dosimeter of ZrO{sub 2} to X-ray beam quality control.

Thermoluminescence study of Cu and Ag doped lithium tetraborate samples synthesized by water/solution assisted method

Energy Technology Data Exchange (ETDEWEB)

Thiyagarajan, S.; Kumar, S.; Vallejo, M.; Sosa, M. [Universidad de Guanajuato, Departamento de Ingenieria Fisica, 37150 Leon, Guanajuato (Mexico); Velusamy, J., E-mail: thiya93@gmail.com [Centro de Investigaciones en Optica, Apdo. Postal 1-948, Leon, Guanajuato (Mexico)

2016-10-15

In this paper lithium tetraborate (Li{sub 2}B{sub 4}O{sub 7}) was produced by water/solution assisted synthesis method. Transition metals, such as Cu and Ag were used to dope Li{sub 2}B{sub 4}O{sub 7} in order to enhance its thermoluminescent properties. The heating temperature parameters for synthesis were 750 degrees Celsius for 2 hours and 150 degrees Celsius for another 2 hours. The samples produced by water assisted method were doped at different doping percentage (0.08, 0.12, 0.5, 0.1 and 1%) of Cu and Ag. Pellets of samples were prepared and there were irradiated with different doses (58, 100, 500 and 945 mGy) by using and X-ray source. The characteristics of undoped and doped Li{sub 2}B-4O{sub 7} were determined by X-ray diffraction (XRD), scanning electron microscopy (Sem), photoluminescence and ultraviolet-visible spectroscopy. The chemical composition and their morphologies of the obtained Li{sub 2}B{sub 4}O{sub 7} and Li{sub 2}B{sub 4}O{sub 7}:Cu, Ag was confirmed by XRD and Sem results. The most intense peak of the XRD pattern of the lithium tetraborate sample was determined by comparing to the reference data and was found to have a tetragonal structure. The thermoluminescent glow curves of the pellets exposed to different doses exhibited a clear response to X-ray irradiation. Especially Li{sub 2}B{sub 4}O{sub 7}:Cu presented a good glow curve in all kind of doses. The experimental results showed that this could have good potential applications in radiation dosimetry. The order of kinetics (b), frequency factor (s) and activation energy (E) or the trapping parameters were calculated using peak shape method. (Author)

An algorithm for unified analysis on the thermoluminescence glow curve

International Nuclear Information System (INIS)

Chung, K.S.; Park, C.Y.; Lee, J.I.; Kim, J.L.

2014-01-01

An algorithm was developed to integrally handle excitation by radiation, relaxation and luminescence by thermal or optical stimulation in thermoluminescence (TL) and optically stimulated luminescence (OSL) processes. This algorithm reflects the mutual interaction between traps through a conduction band. Electrons and holes are created by radiation in the beginning, and these electrons move to the trap through the conduction band. These holes move to the recombination center through a valence band. The ratio of the electrons allocated to each trap differs with the recombination probability and these values also relevant to the process of luminescence. Accordingly, the glow curve can be interpreted by taking the rate of electron–hole pairs created by ionizing radiation as a unique initial condition. This method differs from the conventional method of interpreting the measured glow curve with the initial electron concentration allocated to each trap at the end of irradiation. A program using the Visual Studio's C# subsystem was made to realize such a developed algorithm. To verify this algorithm it was applied to LiF:Mg,Cu,Si. The TL glow curve was deconvoluted with a model of five traps, one deep trap and one recombination center (RC). - Highlights: • TL glow curve deconvolution employing interacting model. • Simulation both irradiation and TL readout stages for various dose level. • Application in the identification TL kinetics of LiF:Mg,Cu,Si TLD

The initial rise method extended to multiple trapping levels in thermoluminescent materials.

Science.gov (United States)

Furetta, C; Guzmán, S; Ruiz, B; Cruz-Zaragoza, E

2011-02-01

The well known Initial Rise Method (IR) is commonly used to determine the activation energy when only one glow peak is presented and analysed in the phosphor materials. However, when the glow peak is more complex, a wide peak and some holders appear in the structure. The application of the Initial Rise Method is not valid because multiple trapping levels are considered and then the thermoluminescent analysis becomes difficult to perform. This paper shows the case of a complex glow curve structure as an example and shows that the calculation is also possible using the IR method. The aim of the paper is to extend the well known Initial Rise Method (IR) to the case of multiple trapping levels. The IR method is applied to minerals extracted from Nopal cactus and Oregano spices because the thermoluminescent glow curve's shape suggests a trap distribution instead of a single trapping level. Copyright © 2010 Elsevier Ltd. All rights reserved.

Radiation induced defects and thermoluminescence mechanism in aluminum oxide

Energy Technology Data Exchange (ETDEWEB)

Atobe, K.; Kobayashi, T.; Awata, T. [Naruto Univ. of Education, Tokushima (Japan); Okada, M. [Kyoto Univ., Kumatori, Osaka (Japan). Research Reactor Inst; Nakagawa, M. [Kagawa Univ., Faculty of Education, Takamatsu, Kagawa (Japan)

2001-01-01

The thermoluminescence of the irradiated aluminum oxides were measured to study the radiation induced defects and their behaviors. Neutron and {gamma}-ray irradiation were performed for a shingle crystal of the high purity aluminum oxide. The thermoluminescence glow curve and its activation energy were measured. The spectroscopy measurement on the thermoluminescence and the absorption are also carried out. The observed 430 and 340 nm peaks are discussed relating to the F{sup +} and F centers, respectively. Activation state of the F center transits to 3P state through 1P state by emitting phonons. Trapped electron on 3P state emits phonon of 2.9 eV (430 nm) during transition to the ground state. The above reaction can be written by the equation. F{sup +} + e {yields} (F){sup *} {yields} F + h{nu}(2.9 eV, 470 nm). (Katsuta, H.)

CVD diamonds as thermoluminescent detectors for medical applications

International Nuclear Information System (INIS)

Marczewska, B.; Olko, P.; Nesladek, M.; Waligorski, M.P.R.; Kerremans, Y.

2002-01-01

Diamond is believed to be a promising material for medical dosimetry due to its tissue equivalence, mechanical and radiation hardness, and lack of solubility in water or in disinfecting agents. A number of diamond samples, obtained under different growth conditions at Limburg University, using the chemical vapour deposition (CVD) technique, was tested as thermoluminescence dosemeters. Their TL glow curve, TL response after doses of gamma rays, fading, and so on were studied at dose levels and for radiation modalities typical for radiotherapy. The investigated CVD diamonds displayed sensitivity comparable with that of MTS-N (Li:Mg,Ti) detectors, signal stability (reproducibility after several readouts) below 10% (1 SD) and no fading was found four days after irradiation. A dedicated CVD diamond plate was grown, cut into 20 detector chips (3x3x0.5 mm) and used for measuring the dose-depth distribution at different depths in a water phantom, for 60 Co and six MV X ray radiotherapy beams. Due to the sensitivity of diamond to ambient light, it was difficult to achieve reproducibility comparable with that of standard LiF detectors. (author)

Dose-rate dependence of thermoluminescence response

International Nuclear Information System (INIS)

McKeever, S.W.S.; Chen, R.; Groom, P.J.; Durrani, S.A.

1980-01-01

The previously observed dose-rate effect of thermoluminescence in quartz at high dose-rates is given at theoretical formulation. Computer calculations simulating the experimental conditions yield similar results to the experimental ones. (orig.)

Study of some thermoluminescent phosphors for the dosimetry of ionizing radiations

International Nuclear Information System (INIS)

Jaafari, M.

1983-01-01

Thermoluminescence dosimetry techniques are reviewed and interactions radiation matter are recalled. The need for new phosphors is evidenced. Numerous phosphors are examined and calcium, strontium and barium sulfides are synthetized and deposited on glass supports. The thermoluminescence of the dosimeters obtained with these materials is analyzed [fr

Photoluminescence and thermoluminescence of K2 Mg(SO4 )2 :Eu and evaluation of its kinetic parameters.

Science.gov (United States)

Deshpande, Archana; Dhoble, N S; Gedam, S C; Dhoble, S J

2017-08-01

The K 2 Mg(SO 4 ) 2 :Eu phosphor, synthesized by a solid-state diffusion method, was studied for its photoluminescence (PL) and thermoluminescence (TL) characteristics. The X-ray diffraction (XRD) pattern of the material was matched with the standard JCPDF No. 36-1499. For PL characteristics, K 2 Mg(SO 4 ) 2 :Eu 2 + showed an emission peak at 474 nm when excited at 340 nm, while it showed Eu 3 + emission at 580 nm, and 594 nm splitting at 613 nm and 618 nm for an excitation of 396 nm wavelength due to radiative transitions from 5 D 0 to 7 F j (j = 0, 1, 2, 3). The Commission International de I' Eclairage (CIE) chromaticity coordinates were also calculated for the K 2 Mg(SO 4 ) 2 :Eu phosphor, and were close to the NTSC standard values. For the TL study, the prepared sample was irradiated using a 60 Co source of γ-irradiation at the dose rate of 0.322 kGy/h for 2 min. The formation of traps in K 2 Mg (SO 4 ) 2 :Eu and the effects of γ-radiation dose on the glow curve are discussed. Well defined broad glow peaks were obtained at 186°C. With increasing γ-ray dose, the sample showed linearity in intensity. The presence of a single glow peak indicated that there was only one set of traps being activated within the particular temperature range. The presented phosphors were also studied for their fading, reusability and trapping parameters. There was just 2% fading during a period of 30 days, indicating no serious fading problem. Kinetic parameters were calculated using the initial rise method and Chen's half-width method. Activation energy and frequency factor were found to be 0.77 eV and 1.41 × 10 6  sec -1 . Copyright © 2016 John Wiley & Sons, Ltd.

Thermoluminescence properties of micro and nano structure hydroxyapatite after gamma irradiation

Energy Technology Data Exchange (ETDEWEB)

Shafaei, Mostafa; Ziaie, Farhood; Hajiloo, Nahid [Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of). Radiation Application Research School

2016-12-15

The goal of this study is to compare the thermoluminescence properties of nano and micro structure hydroxyapatite. Nano structure hydroxyapatite was synthesized via hydrolysis method, while the micro structure one was from Merck Company. X-ray diffraction and fourier transform infrared spectroscopy were used to determine the crystal structure and chemical composition of the hydroxyapatite samples. Particles sizes of each sample were estimated using Scherer equation and transmission electron microscopy system. Thermoluminescence properties of the samples were investigated under gamma irradiation. The glow curves of micro and nano structure samples show a peak at 150 C and 200 C, respectively. Thermoluminescence responses of both the samples were linear in the range of 25 - 1 000 Gy where, nano structure sample show a greater slope and stronger linearity in comparison to the micro sample. The results show that the thermoluminescence response of micro sample faded rapidly in comparison to the nano sample due to the existence of the peak at higher temperature.

Thermoluminescence sensitivity variations in LiF PTFE dosemeters incurred by improper handling procedures

CERN Document Server

Mason, E W; MacKinlay, Alistair F; Saunders, D

1975-01-01

A systematic study of some anomalous darkening effects and thermoluminescence sensitivity variations observed in LiF:PTFE thermoluminescent dosemeters is described. Various likely causes of such effects have been investigated. The manufacturer's recommended cleaning procedures have been found to be inadequate and, in some cases, have been found to actually promote discolouration of the dosemeters. Recommendations are given for the successful use of LiF:PTFE thermoluminescent dosemeters in personal dosimetry.

Thermoluminescence of strontium tetraborate

International Nuclear Information System (INIS)

Santiago, M.; Caselli, E.; Lester, M.

1999-01-01

The thermoluminescent properties of crystalline strontium tetraborate are reported. Without activators it has an efficiency comparable to that of TLD-700 powder. Its fading after 40 days amount to less than 2%. The isometric plot shows that most of the emitted light is concentrated at wavelengths ranging from 350 to 450 nm, which accounts partially for the high efficiency. (author)

Variation in thermoluminescence of irradiated brands of foodstuffs: a test for hygienic quality

International Nuclear Information System (INIS)

Mamoon, A.; Zaheer, A.; Abu-Abdullah, S.

1996-01-01

Thermoluminescence of irradiated foodstuffs such as herbs and spices, is mostly due to attached dust or soil particles. Different brands of the same foodstuff sometimes give thermoluminescent signals of different intensities, apparently due to different degrees of dust contamination. It is of obvious importance to choose brands of foodstuffs that appear to have less dust contamination, i.e. of better hygienic quality. Several food items were investigated with respect to their thermoluminescent (TL) emission in order to assess TL usefulness as an indicator of hygienic quality for foods prone to contamination by dust. In this regard some foodstuff were artificially contaminated with a soil sample and their thermoluminescent emission was obtained. (author)

Thermoluminescence characteristics of the irradiated minerals extracted from red pepper (Capsicum annum L.) spice

Energy Technology Data Exchange (ETDEWEB)

Marcazzo, J.; Cruz Z, E.; Montiel, L. [UNAM, Instituto de Ciencias Nucleares, A. P. 70-543, 04510 Mexico D. F. (Mexico); Chernov, V. [Universidad de Sonora, Centro de Investigacion en Fisica, A. P. 5-088, 83190 Hermosillo, Sonora (Mexico); Calderon, T., E-mail: ecruz@nucleares.unam.mx [Universidad Autonoma de Madrid, Facultad de Ciencias, Departamento de Quimica Agricola, 28049 Cantoblanco, Madrid (Spain)

2012-06-15

The inorganic poly mineral content in the foodstuffs allows to analyze the main thermoluminescence (Tl) characteristics that may be useful in the identification of irradiated food. The mineral fraction was separated from commercial Mexican red pepper (Capsicum annum L.). X-ray diffraction shows that the mineral composition of the samples was mainly quartz. From the mineral fraction of different grain sizes, samples of 149 {mu}m were selected for this study because of the high Tl signals. The samples were irradiated from 1 to 500 Gy by using a {sup 60}Co irradiator. The Tl characteristics like glow curve shape, dose-response, UV and sunlight bleaching and fading were analyzed. The glow curves show an intense Tl peak at 82 C followed by others with less intensity at 130, 170 and 340 C. The T{sub M}-T{sub STOP} method shows six Tl glow peaks that was taken into account for calculation the activation energies values. Because the complex structure of the glow curves, the kinetics parameters were determined by using a computerized deconvolution program assuming the general order kinetics model. (Author)

Thermoluminescence characteristics of the irradiated minerals extracted from red pepper (Capsicum annum L.) spice

International Nuclear Information System (INIS)

Marcazzo, J.; Cruz Z, E.; Montiel, L.; Chernov, V.; Calderon, T.

2012-01-01

The inorganic poly mineral content in the foodstuffs allows to analyze the main thermoluminescence (Tl) characteristics that may be useful in the identification of irradiated food. The mineral fraction was separated from commercial Mexican red pepper (Capsicum annum L.). X-ray diffraction shows that the mineral composition of the samples was mainly quartz. From the mineral fraction of different grain sizes, samples of 149 μm were selected for this study because of the high Tl signals. The samples were irradiated from 1 to 500 Gy by using a 60 Co irradiator. The Tl characteristics like glow curve shape, dose-response, UV and sunlight bleaching and fading were analyzed. The glow curves show an intense Tl peak at 82 C followed by others with less intensity at 130, 170 and 340 C. The T M -T STOP method shows six Tl glow peaks that was taken into account for calculation the activation energies values. Because the complex structure of the glow curves, the kinetics parameters were determined by using a computerized deconvolution program assuming the general order kinetics model. (Author)

Investigation of the thermoluminescent properties of nanosized Alpha-Al2 O3 doped with carbon for application in digital radiography

International Nuclear Information System (INIS)

Silva, Edna C.

2013-01-01

Thermoluminescent (TL) materials are mainly used in personal and environmental dosimetry. In addition to these applications, their use as the sensor element in the manufacturing of digital radiographic films has been investigated. Particularly, there is an interest concerned to the influence of the particle size in the TL response and in the resolution of the digital imaging. Aluminum oxide, or alumina, is a mineral found in the ruby or sapphire form, and may be synthetically produced in the alpha or gamma crystalline phase. Since the 50s, these materials have been studied in their diverse forms and phases. Particularly, the microsized α-Al 2 O 3 :C is considered one of the best TL dosimeter ever produced in the word. In this work, nanosized alumina particulates in the alpha phase, sintered at different temperatures and doped with different concentrations of carbon, were investigated aiming application in industrial radiography and medical diagnosis. The mixture of the oxide powder with the carbon source was pressed and sintered at temperatures of 1740 deg C and 1745 deg C, under reducing atmosphere. For doping purposes we have used two sources of carbon, graphite and high purity polyvinyl acetate (PVA), respectively. During the sintering process, intentional inclusion of oxygen vacancies into the oxide crystal lattice is performed, allowing the inclusion of carbon atoms into the crystal lattice. Among the samples studied, the nanosized alumina doped with 0.01at.% of carbon and sintered at 1745 deg C has shown an excellent thermoluminescent response, with sensitivity higher than that of LiF: Mg, Ti (TLD-100), when irradiated under similar conditions. This is an excellent result, since the material with nanosized particles offers the best features for radiographic image. Thus, it is concluded that the α-Al 2 O 3 doped with 0.01at.% of carbon is a good candidate for use in TL films for application in digital radiography. (author)

Thermoluminescence of Zn O thin films deposited by chemical bath

International Nuclear Information System (INIS)

Camacho A, M. C.; Cruz V, C.; Bernal H, R.; Berman M, D.; Castano M, V. M.

2015-10-01

Full text: Zn O films on Si were synthesized using a deposition method by chemical bath and thermally treated at 900 degrees C for 12 h in air. The morphological characterization by scanning electron microscopy reveals that uniform films were obtained. To investigate the thermoluminescent properties of the films were exposed to irradiation with beta particles with doses in the range from 0.5 to 128 Gy. The brightness curves obtained using a heating rate of 5 degrees C have two peaks, one at 124 and another at 270 degrees C, and a linear dependence of the integrated thermoluminescence as a function of dose. The second maximum reveals the existence of localized trapping states of potential utility in thermoluminescent dosimetry. (Author)

Thermoluminescent characteristics of ZrO2:Nd films

International Nuclear Information System (INIS)

Vera B, G.; Rivera M, T.; Azorin N, J.; Falcony G, C.; Garcia H, M.; Martinez S, E.

2002-01-01

In this work it is exposed the obtained results after analysing the photo luminescent and thermoluminescent characteristics of activated zirconium oxide with neodymium (ZrO 2 :Nd) and its possible application in the UV radiation dosimetry. The realized experiments had as objective to study the characteristics such as the optimum thermal erased treatment, the influence of light on the response, the response depending on the wavelength, the fadeout of the information, the temperature effect, the response depending on the time and the recurring of the response. The results show that the ZrO 2 :Nd is a promising material to be used as Tl dosemeter for the UV radiation. (Author)

Thermoluminescent response of LiF before variation of the heating rate

International Nuclear Information System (INIS)

Barrios, R.; Avila, O.

2003-01-01

Comparisons of glow curves of lithium fluoride dosemeters TLD-100 measured to two heating rates with the purpose of quantifying the change in the temperature of the peaks 5 and 7 for the thermoluminescent reader equipment Harshaw 4000 of the thermoluminescence laboratory of the ININ were carried out. (Author)

Thermoluminescence properties of CaO powder obtained from chicken eggshells

Science.gov (United States)

Nagabhushana, K. R.; Lokesha, H. S.; Satyanarayana Reddy, S.; Prakash, D.; Veerabhadraswamy, M.; Bhagyalakshmi, H.; Jayaramaiah, J. R.

2017-09-01

Eggshell wastage has created serious problem in disposal of the food processing industry which has been triggered the thoughts of researchers to use wasted eggshells as good source of calcium. In the present work, calcium oxide (CaO) has been synthesized by combustion process in furnace (F-CaO) and microwave oven (M-CaO) using the source of chicken eggshells. The obtained F-CaO and M-CaO are characterized by XRD, SEM with EDX and thermoluminescence (TL) technique. XRD pattern of both the samples show cubic phase with crystallite size 45-52 nm. TL glow curves are recorded for various gamma radiation dose (300-4000 Gy). Two TL glows, a small peak at 424 K and stronger peak at 597 K are observed. TL response of M-CaO is 2.67 times higher than F-CaO sample. TL kinetic parameters are calculated by computerized curve deconvolution analysis (CCDA) and discussed.

Thermoluminescence of LaAlO{sub 3}; Termoluminescencia de LaAlO{sub 3}:Dy

Energy Technology Data Exchange (ETDEWEB)

Morales H, A.; Zarate M, J. [Universidad Michoacana de San Nicolas de Hidalgo, Instituto de Investigacion en Metalurgia y Materiales, Ciudad Universitaria, Edif. U, 58060 Morelia, Michoacan (Mexico); Rivera M, T. [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Av. Legaria 694, 11500 Mexico D. F. (Mexico); Azorin N, J., E-mail: feyo_yo@hotmail.com [Universidad Autonoma Metropolitana, Unidad Iztapalapa, Av. San Rafael Atlixco 186, Col. Vicentina, 09340 Mexico D. F. (Mexico)

2015-10-15

In this paper the thermoluminescent properties of doped lanthanum aluminate (LaAlO{sub 3}) with dysprosium ion (Dy) were studied. The thermoluminescence characteristics in the samples were obtained using an ultraviolet radiation of 220 nm. The LaAlO{sub 3}:Dy samples were prepared by the modified Pechini method (Spray Dryer). The structural and morphological characterization was obtained by X-ray diffraction (XRD) and scanning electron microscopy (Sem) techniques respectively. The size particle composing the agglomerate was determined by Sem, agglomerated particles composed size of 2μm were observed. The thermoluminescence response of LaAlO{sub 3}:Dy was compared with that obtained with the undoped sample. Thermoluminescence brightness curves of LaAlO{sub 3}:Dy showed a peak centered at 185 grades C. Sensitivity of doped sample was greater, about 100 times compared with the undoped sample. Thermoluminescence response in function of the wavelength showed a maximum at 220 nm. Also the fading in thermoluminescence response was studied. (Author)

Photoluminescence and thermoluminescence characterization of Eu3+- and Dy3+ -activated Ca3(PO4)2 phosphor

International Nuclear Information System (INIS)

Nagpure, I.M.; Saha, Subhajit; Dhoble, S.J.

2009-01-01

Rare-earth-doped polycrystalline Ca 3 (PO 4 ) 2 :Eu, Ca 3 (PO 4 ) 2 :Dy and Ca 3 (PO 4 ) 2 :Eu,Dy phosphors prepared by a modified solid-state synthesis has been studied for its X-ray diffraction, thermoluminescence (TL) and photoluminescence (PL) characteristics. The PL emission spectra of the phosphor suggest the presence of Eu 3+ ion in Ca 3 (PO 4 ) 2 :Eu and Dy 3+ ion in Ca 3 (PO 4 ) 2 :Dy lattice sites. The TL glow curve of the Ca 3 (PO 4 ) 2 :Eu compounds has a simple structure with a prominent peak at 228 deg. C, while Ca 3 (PO 4 ) 2 :Dy peaking at 146 and 230 deg. C. TL sensitivity of phosphors are compared with CaSO 4 : Dy and found 1.52 and 1.20 times less in Ca 3 (PO 4 ) 2 :Eu and Ca 3 (PO 4 ) 2 :Dy phosphors, respectively. The Ca 3 (PO 4 ) 2 :Eu,Dy phosphors shows switching behavior under two different excitation wavelengths and enhancement in PL intensity of Dy 3+ ions were reported. The paper discusses the photoluminescence and thermoluminescence behavior of Eu 3+ and Dy 3+ ion in Ca 3 (PO 4 ) 2 hosts, it may be applicable to solid-state lighting as well as thermoluminescence dosimetry applications.

Thermoluminescent dosemeter in a X-ray diffractometer

International Nuclear Information System (INIS)

Mendoza A, D.; Gonzalez M, P.; Falcon B, T.; Castano, V.M.

1999-01-01

In this work it was presented the results obtained of the dosimetry which was realized in a X-ray diffractometer for powders, trademark Siemens D5000, using the thermoluminescent signal generated by the X-rays in the commercial dosemeter TLD-100 of Harshaw, US. In according to the results obtained, the radiation quantity received by an analysed material in the diffractometer, will be proportional to exposure time and it can vary from unities until tenths of grays. These results are very outstanding when are analysed crystalline materials in a diffractometer, for knowing the present crystalline phases, mainly if these are highly sensitive to the ionizing radiation, as it is the case of the thermoluminescent materials. (Author)

Thermoluminescence properties of AlN ceramics

DEFF Research Database (Denmark)

Trinkler, L.; Christensen, P.; Agersnap Larsen, N.

1998-01-01

The paper describes thermoluminescence (TL) properties of AlN:Y2O3 ceramics irradiated with ionising radiation. A high TL sensitivity of AlN:Y2O3 ceramics to radiation encouraged a study of the AlN ceramics for application as a dosimetric material. The paper presents experimental data on: glow...... curve, emission spectrum, dose response, energy dependence, influence of heating rate and fading rate. The measured TL characteristics were compared with those of well-known, widely used TLDs, i.e. LiF:Mg,Ti, LiF:Mg,Cu,P and Al2O3:C. It is concluded that AlN:Y2O3 ceramics showing a radiation sensitivity...... which is approximately 50 times greater than that of LiF:Mg,Ti is an interesting dosimetry material; however due to a high fading rate of the TL of AlN:Y2O3 on storage at room temperature, a further development of the material for improving the fading characteristics is needed for its application...

Thermoluminescence spectra of amethyst

Energy Technology Data Exchange (ETDEWEB)

Zhang, Q. [Suzhou Railway Teachers College (China). Dept. of Physics; Yang, B. [Beijing Normal University (China). Dept. of Physics; Wood, R.A.; White, D.R.R.; Townsend, P.D.; Luff, B.J. [Sussex Univ., Brighton (United Kingdom). School of Mathematical and Physical Sciences

1994-04-01

Thermoluminescence and cathodoluminescence data from natural and synthetic amethyst and synthetic quartz samples are compared. The spectra include features from the quartz host lattice and from impurity-generated recombination sites. Emission features exist throughout the wavelength range studied, 250-800 nm. The near infrared emission at 740-750 nm appears to be characteristic of the amethyst and is proposed to be due to Fe ion impurity. (Author).

Laser readable thermoluminescent radiation dosimeters and methods for producing thereof

International Nuclear Information System (INIS)

Braunlich, P.F.; Tetzlaff, W.

1989-01-01

Thin layer thermoluminescent radiation dosimeters for use in laser readable dosimetry systems, and methods of fabricating such thin layer dosimeters are disclosed. The thin layer thermoluminescent radiation dosimeters include a thin substrate made from glass or other inorganic materials capable of withstanding high temperatures and high heating rates. A thin layer of a thermoluminescent phosphor material is heat bonded to the substrate using an inorganic binder such as glass. The dosimeters can be mounted in frames and cases for ease in handling. Methods of the invention include mixing a suitable phosphor composition and binder, both being in particulate or granular form. The mixture is then deposited onto a substrate such as by using mask printing techniques. The dosimeters are thereafter heated to fuse and bond the binder and phosphor to the substrate. 34 figs

Thermoluminescence studies on plant seeds of different radiosensitivity

International Nuclear Information System (INIS)

Yamaguchi, Hikoyuki; Eguchi, Hoshio; Koizumi, Yoshinobu.

1975-01-01

The thermoluminescence was found when the pulverized powders from the whole seeds of six plant species or the hypocotyls from the seeds of five soybean varieties were irradiated at a liquid nitrogen temperature with gamma-rays. The spectra of luminescence emitted, the light peak temperature, the decaying after irradiation and the dose relationship of luminescence were determined. A high yield of the rapidly-decaying luminescence occurred in the more radiosensitive variety when irradiated with relatively lower doses. The very drastic decrease of the thermoluminescence was observed in the samples irradiated at room temperature prior to the exposure at 77 0 K. (auth.)

Effect of Annealing on the Thermoluminescence Properties of ZnO Nanophosphor

Science.gov (United States)

Kalita, J. M.; Wary, G.

2017-07-01

We report the effect of annealing on the thermoluminescence (TL) properties of zinc oxide (ZnO) nanophosphor. The sample was synthesised by a wet chemical process. The characterisation report shows that the size of the grains is within 123.0 nm-160.5 nm. TL measured at 2 K/s from a fresh un-annealed sample irradiated to 60 mGy shows a composite glow curve containing three peaks at 353.2 K, 429.1 K, and 455.3 K. On the other hand, samples annealed at 473 K and 573 K followed by irradiation to 60 mGy do not give TL. However, annealing at 673 K and 773 K followed by irradiation to the same dose produces a glow curve comprising two overlapping peaks at 352.3 K and 370.6 K. In the TL emission spectrum of un-annealed sample, two emission peaks were found in green ( 523 nm) and orange ( 620 nm) regions whereas in annealed samples, only a peak was found in the orange region ( 618 nm). Kinetic analysis shows that the activation energy corresponding to TL peaks at 353.2 K, 429.1 K, and 455.3 K of the un-annealed sample are 0.64 eV, 0.80 eV, and 1.20 eV whereas that of the peaks at 352.3 K and 370.6 K of 673 K and 773 K annealed samples are 0.64 eV and 0.70 eV, respectively. All peaks of un-annealed and annealed samples, except the one at 429.1 K of the un-annealed sample, follow first-order kinetics whereas the peak at 429.1 K follows second-order kinetics. Considering the kinetic and spectral features, an energy band model for ZnO nanophosphor has been proposed.

New 2-D dosimetric technique for radiotherapy based on planar thermoluminescent detectors

International Nuclear Information System (INIS)

Olko, P.; Marczewska, B.; Czopyk, L.; Czermak, M. A.; Klosowski, M.; Waligorski, M. P. R.

2006-01-01

At the Inst. of Nuclear Physics of the Polish Academy of Sciences (IFJ) in Krakow, a two-dimensional (2-D) thermoluminescence (TL) dosimetry system was developed within the MAESTRO (Methods and Advanced Equipment for Simulation and Treatment in Radio-Oncology) 6 Framework Programme and tested by evaluating 2-D dose distributions around radioactive sources. A thermoluminescent detector (TLD) foil was developed, of thickness 0.3 mm and diameter 60 mm, containing a mixture of highly sensitive LiF:Mg,Cu,P powder and Ethylene Tetrafluoroethylene (ETFE) polymer. Foil detectors were irradiated with 226 Ra brachytherapy sources and a 90 Sr/ 90 Y source. 2-D dose distributions were evaluated using a prototype planar (diameter 60 mm) reader, equipped with a 12 bit Charge Coupled Devices (CCD) PCO AG camera, with a resolution of 640 x 480 pixels. The new detectors, showing a spatial resolution better than 0.5 mm and a measurable dose range typical for radiotherapy, can find many applications in clinical dosimetry. Another technology applicable to clinical dosimetry, also developed at IFJ, is the Si microstrip detector of size 95 x 95 mm 2 , which may be used to evaluate the dose distribution with a spatial resolution of 120 μm along one direction, in real-time mode. The microstrip and TLD technology will be further improved, especially to develop detectors of larger area, and to make them applicable to some advanced radiotherapy modalities, such as intensity modulated radiotherapy (IMRT) or proton radiotherapy. (authors)

Kinetic chains: a review of the concept and its clinical applications.

Science.gov (United States)

Karandikar, Ninad; Vargas, Oscar O Ortiz

2011-08-01

During the past decade, our understanding of biomechanics and its importance in rehabilitation has advanced significantly. The kinetic chain, a concept borrowed from engineering, has helped us better understand the underlying physiology of human movement. This understanding, in turn, has facilitated the development of new and more rational rehabilitation strategies. The kinetic chain concept has application in a wide spectrum of clinical conditions, including musculoskeletal medicine, sports medicine, and neurorehabilitation, as well as prosthetics and orthotics. The purpose of this review is to provide insights into the biomechanics related to the concept of kinetic chains, with a specific focus on closed kinetic chains and its clinical applications in rehabilitation. Copyright © 2011 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

Synthesis and thermoluminescence properties of CaF2:Tm,Ce nanoparticles

Directory of Open Access Journals (Sweden)

M Zahedifar

2013-10-01

Full Text Available Calcium fluoride nanoparticles doped with thulium and cerium were synthesized as a novel nanostructure by using the hydrothermal method. The prepared samples were characterized by X-ray diffraction (XRD and energy dispersive spectrometer (EDS. The crystallite size of about 36 nm was estimated employing Scherer’s formula. Its shape and size were also observed by scanning electron microscope (SEM. Computerized glow curve deconvolution (CGCD technique revealed two overlapping thermoluminescence glow peaks at around 402 and 457 K in the complex thermoluminescence glow curve of this phosphor. Other thermoluminescence characteristics of this phosphor such as fading, reuseability and dose response recommend it as a good candidate for high dose dosimetry.

Relationship between thermoluminescence and X-ray induced luminescence in alkali halides

International Nuclear Information System (INIS)

Aguilar, M.; Lopez, F.J.; Jaque, F.

1978-01-01

The wavelength spectra of thermoluminescence and X-ray induced luminescence in pure and divalent cation doped alkali halides, in the temperature range LNT-RT have been studied. The more important conclusion is that the wavelength spectra in both cases are very similar. This allows a new point of view to be presented on thermoluminescence mechanisms. (author)

Preparation of thermoluminescent dosimeters of LiF: Mg, Cu, P + Ptfe for environmental radiological monitoring and radiodiagnosis; Preparacion de dosimetros termoluminiscentes de LiF: Mg, Cu, P + PTFE para monitoreo radiologico ambiental y radiodiagnostico

Energy Technology Data Exchange (ETDEWEB)

Ramirez L, A

1997-12-31

The necessity of finding a thermoluminescent material for measuring gamma and X radiation in applications like environmental monitoring, personnel dosimetry and biomedical sciences (radiotherapy and radiodiagnosis), but with special characteristics such as low umbral detection, independence of the energy of radiation and equivalency with the tissue. This made us think in lithium fluoride activated with magnesium, copper and phosphorous (LiF: Mg, Cu, P). In this thesis I developed this material chips like shape embedded in polytetrafluoroethylene (LiF: Mg, Cu, P+Ptfe). The chapter 1 and 2 talk about the atom is conformed and the interaction of the radiation with the matter. The requirements of Tl material, types of dosimetry system, biological effects and units of measurements are discussed in chapter 3 as well as the recommended limits of the International Commission on Radiological Protection ICRP. Chapter 4 shows aspects of the thermoluminescence phenomenon and describes, at the same time, the determination of the most important thermoluminescent parameters (kinetic order, energy or trap depth and the frequency factor). Chapter 5 describes the major characteristics and properties of Tl materials and its requirements for dosimetric use. Chapter 6 deals with the preparations of LiF: Mg, Cu, P+Ptfe chips and some tests for improving its sensitivity, describes the dosimetric tests and requirements proposed by American National Standard Institute ANSI-N545 Like: umbral of detection, homogeneity, fading, repeatability, linearity, effects of UV and fluorescent light etc. Finally in chapter 7 I do a report about analysis of results, conclusions and some recommendations. (Author).

Cathodoluminescence and Thermoluminescence of Undoped LTB and LTB:A (A = Cu, Ag, Mn)

Science.gov (United States)

2013-03-01

and Mn Ions for Nonlinear Applications.” Acta Physica Polonica A 107, no. 3 (2005): 507-518. [22] Kimball Physics, Inc.. Operator’s Manual: EMG...CATHODOLUMINESCENCE AND THERMOLUMINESCENCE OF UNDOPED LTB AND LTB:A ( A = Cu, Ag, Mn) THESIS Zachary L. Hadfield, USA AFIT-ENP-13-M-13...STATEMENT A . APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED The views expressed in this thesis are those of the author and

Dosimetric behavior of thermoluminescent dosimeters at low doses in diagnostic radiology

International Nuclear Information System (INIS)

Del Sol F, S.; Garcia S, R.; Guzman M, J.; Sanchez G, D.; Rivera M, T.; Ramirez R, G.; Gaona, E.

2015-10-01

Thermoluminescent (Tl) characteristics of TLD-100, LiF:Mg,Cu,P, and CaSO 4 : Dy the under homogeneous field of X-ray beams of diagnostic irradiation and its verification using thermoluminescent dosimetry is presented. The irradiations were performed utilizing an X-ray beam generated by a Radiology Mexican Company: MRH-II E GMX 325-AF SBV-1 model, with Rotating Anode X-Ray Tube installed in the Hospital Juarez Norte de Mexico in Mexico City. Different thermoluminescent characteristics of dosimetric material were studied, such as, batch homogeneity, Tl glow curve, Tl response as a function of X-ray dose, reproducibility and fading. Materials were calibrated in terms of absorbed dose to the standard calibration distance and positioned in a generic Phantom was used. Dose verification and comparison with the measurements made with that obtained by TLD-100 were analyzed. Preliminary results indicate the dosimetric peak appears at 243, 236 and 277 ± 5 degrees C respectively, these peaks are in agreement with that reported in the literature. Tl glow curve as a function of X-ray dose showed a linearity in the range from 1.76 mGy up to 14.70 mGy for all materials. Fading for a period of one month at room temperature showed low fading LiF:Mg,Cu,P, medium and high for TLD-100 and CaSO 4 : Dy. The results suggest that the three materials are suitable for measurements at low doses in radiodiagnostic, however, for its dosimetric characteristics are most effective for individual applications: personal dosimetry and monitors limb (LiF:Mg,Cu,P), clinical dosimetry and environmental (TLD-100 and CaSO 4 : Dy). (Author)

Re-use of radio-thermoluminescent LiF without regeneration; Reemploi sans regeneration du LiF radiothermoluminescent

Energy Technology Data Exchange (ETDEWEB)

Portal, G; Francois, H; Blanchard, Ph [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

1969-07-01

There is at the present time a rapid development of dosimetry techniques using thermoluminescence. Amongst the many substance actually in use, research laboratories generally employ lithium fluoride which is of particular interest for dosing {beta} radiation and low-energy X and {gamma} radiation. It might also be of use in radioprotection if its practical application were simpler. It has in effect unstable traps situated just below the surface which adversely affect the measurements if the material is not regenerated before each operation; this process considerably complicates the carrying out of measurements in the field of radioprotection. We have prepared a lithium fluoride giving unstable peaks which are less pronounced that those of the commercially available product and which can therefore be used without regeneration. In this report we compare the thermoluminescence curves for these two products. An analysis is given of the reasons for which this radio-thermoluminescent product has a stable luminescence curve and can be used almost one hundred times without being regenerated. We show that this quality can be retained when the LiF is used as a filler for teflon for applications in detectors. (authors) [French] On assiste a un developpement rapide des techniques de dosimetrie par thermoluminescence. Parmi les nombreux materiaux actuellement utilises, les laboratoires de recherche font generalement porter leur preference sur le fluorure de lithium qui est particulierement interessant pour la dosimetrie des rayonnements {beta} et des rayonnements X et {gamma} de faible energie. Ses qualites seraient egalement appreciees en radioprotection si sa mise en oeuvre etait plus simple. Il presente en effet des pieges instables situes a une faible profondeur qui alterent les mesures si l'on ne procede pas, avant chaque utilisation, a la regeneration du materiau, operation qui alourdit considerablement les mesures pratiquees en radioprotection. Nous avons prepare un

Issues in the reconstruction of environmental doses on the basis of thermoluminescence measurements in the Techa riverside

Science.gov (United States)

Bougrov, N. G.; Goksu, H. Y.; Haskell, E.; Degteva, M. O.; Meckbach, R.; Jacob, P.; Neta, P. I. (Principal Investigator)

1998-01-01

The potential of thermoluminescence measurements of bricks from the contaminated area of the Techa river valley, Southern Urals, Russia, for reconstructing external exposures of affected population groups has been studied. Thermoluminescence dating of background samples was used to evaluate the age of old buildings available on the river banks. The anthropogenic gamma dose accrued in exposed samples is determined by subtracting the natural radiation background dose for the corresponding age from the accumulated dose measured by thermoluminescence. For a site in the upper Techa river region, where the levels of external exposures were extremely high, the depth-dose distribution in bricks and the dependence of accidental dose on the height of the sampling position were determined. For the same site, Monte Carlo simulations of radiation transport were performed for different source configurations corresponding to the situation before and after the construction of a reservoir on the river and evacuation of the population in 1956. A comparison of the results provides an understanding of the features of the measured depth-dose distributions and height dependencies in terms of the source configurations and shows that bricks from the higher sampling positions are likely to have accrued a larger fraction of anthropogenic dose from the time before the construction of the reservoir. The applicability of the thermoluminescent dosimetry method to environmental dose reconstruction in the middle Techa region, where the external exposure was relatively low, was also investigated.

Thermoluminescence properties of Eu and Li co-doped Gd2O3, induced by UV light

International Nuclear Information System (INIS)

Hristov, H; Arhangelova, N; Velev, V; Uzunov, N M; Baneva, Y; Nedeva, D; Penev, I; Moschini, G; Rossi, P

2012-01-01

For some specific biomedical applications, connected with in-situ measurements of the absorbed dose of ultraviolet (UV) light, we have developed materials, sensitive to the light emission with a wavelength up to 320nm. Thermoluminescence (TL) yield of Gd 2 O 3 , doped with Eu and Li has been analysed with respect to the quantity of Li co-dopant. Lithium has been added as Li 2 CO 3 to a mixture of Gd 2 O 3 with 10 wt% Eu 2 O 3 . Pellets with the mixture have been sintered at a temperature of 1000°C. The kinetic parameters of the phosphors thus obtained have been studied from the TL glow curves after irradiation with UV light. It has been demonstrated that the addition of 16 wt% of Li 2 CO 3 to the Eu-doped Gd 2 O 3 yields a maximum intensity of the peaks at 87°C and at 145°C. Studies on the kinetic parameters as well as the TL properties of Eu-doped Gd 2 O 3 with the addition of 16% of Li 2 CO 3 have been conducted. It has been measured that two of the TL peaks of this phosphor have relatively long fading. Analysis of the TL properties of the phosphors obtained from Gd 2 O 3 , doped with Eu and Li, shows that they possess good sensitivity to the UV emission and could be used as appropriate phosphors for detection and quantitative measurements of UV light.

Competition between excitation and bleaching of thermoluminescence

International Nuclear Information System (INIS)

Chen, R.; Hornyak, W.F.

1990-01-01

The bleaching of thermoluminescence (TL) yield to a residual value by light is explained, at least in some cases, to be due to an equilibrium between excitation and de-excitation by the illuminating light. Kinetic differential equations are given governing the process for the simple case of a single trapping state for electrons and a single variety of hole recombination centre. The equations are solved numerically for chosen sets of the relevant parameters starting either from empty traps and centres or from highly populated ones. In agreement with experimental results, the numerical computation predicts that after a long enough illumination the process of filling of the traps converges to the same equilibrium value as that produced by bleaching. It is also found that the equilibrium value is independent of the intensity, though, of course, this is approached faster with more intense light. The computed dependencies of the filling of trapping states as a function of illumination time are shown. The final equilibrium value for the filling of trapping states can also be evaluated analytically for any set of given parameters; these compare very favourably with the calculated results. The change of the results with the variation of the relevant parameters is discussed. (author)

Thermoluminescence as a complementary technique for the toxicological evaluation of chemicals in photosynthetic organisms

Energy Technology Data Exchange (ETDEWEB)

Repetto, Guillermo, E-mail: grepkuh@upo.es [Departamento de Biología Molecular e Ingeniería Bioquímica, Área de Toxicología, Universidad Pablo de Olavide, Carretera de Utrera km. 1, 41013 Seville (Spain); Zurita, Jorge L. [Departamento de Biología Molecular e Ingeniería Bioquímica, Área de Toxicología, Universidad Pablo de Olavide, Carretera de Utrera km. 1, 41013 Seville (Spain); Roncel, Mercedes; Ortega, José M. [Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Américo Vespucio 49, 41092 Seville (Spain)

2015-01-15

Highlights: • There are very few toxicological applications of thermoluminescence. • It is a luminescence emission induced by heating the sample in the dark. • It is useful for study the photosystem II function and the level of lipid peroxidation. - Abstract: Thermoluminescence is a simple technique very useful for studying electron transfer reactions on photosystem II (standard thermoluminescence) or the level of lipid peroxidation in membranes (high temperature thermoluminescence) in photosynthetic organisms. Both techniques were used to investigate the effects produced on Chlorella vulgaris cells by six compounds: the chemical intermediates bromobenzene and diethanolamine, the antioxidant propyl gallate, the semiconductor indium nitrate, the pesticide sodium monofluoroacetate and the antimalarial drug chloroquine. Electron transfer activity of the photosystem II significantly decreased after the exposure of Chlorella cells to all the six chemicals used. Lipid peroxidation was slightly decreased by the antioxidant propyl gallate, not changed by indium nitrate and very potently stimulated by diethanolamine, chloroquine, sodium monofluoroacetate and bromobenzene. For five of the chemicals studied (not bromobenzene) there is a very good correlation between the cytotoxic effects in Chlorella cells measured by the algal growth inhibition test, and the inhibition of photosystem II activity. The results suggest that one very important effect of these chemicals in Chlorella cells is the inhibition of photosynthetic metabolism by the blocking of photosystem II functionality. In the case of sodium monofluoroacetate, diethanolamine and chloroquine this inhibition seems to be related with the induction of high level of lipid peroxidation in cells that may alter the stability of photosystem II. The results obtained by both techniques supply information that can be used as a supplement to the growth inhibition test and allows a more complete assessment of the effects of

Thermoluminescence as a complementary technique for the toxicological evaluation of chemicals in photosynthetic organisms

International Nuclear Information System (INIS)

Repetto, Guillermo; Zurita, Jorge L.; Roncel, Mercedes; Ortega, José M.

2015-01-01

Highlights: • There are very few toxicological applications of thermoluminescence. • It is a luminescence emission induced by heating the sample in the dark. • It is useful for study the photosystem II function and the level of lipid peroxidation. - Abstract: Thermoluminescence is a simple technique very useful for studying electron transfer reactions on photosystem II (standard thermoluminescence) or the level of lipid peroxidation in membranes (high temperature thermoluminescence) in photosynthetic organisms. Both techniques were used to investigate the effects produced on Chlorella vulgaris cells by six compounds: the chemical intermediates bromobenzene and diethanolamine, the antioxidant propyl gallate, the semiconductor indium nitrate, the pesticide sodium monofluoroacetate and the antimalarial drug chloroquine. Electron transfer activity of the photosystem II significantly decreased after the exposure of Chlorella cells to all the six chemicals used. Lipid peroxidation was slightly decreased by the antioxidant propyl gallate, not changed by indium nitrate and very potently stimulated by diethanolamine, chloroquine, sodium monofluoroacetate and bromobenzene. For five of the chemicals studied (not bromobenzene) there is a very good correlation between the cytotoxic effects in Chlorella cells measured by the algal growth inhibition test, and the inhibition of photosystem II activity. The results suggest that one very important effect of these chemicals in Chlorella cells is the inhibition of photosynthetic metabolism by the blocking of photosystem II functionality. In the case of sodium monofluoroacetate, diethanolamine and chloroquine this inhibition seems to be related with the induction of high level of lipid peroxidation in cells that may alter the stability of photosystem II. The results obtained by both techniques supply information that can be used as a supplement to the growth inhibition test and allows a more complete assessment of the effects of

Thermoluminescence in medical dosimetry; Termoluminiscencia en dosimetria medica

Energy Technology Data Exchange (ETDEWEB)

Rivera, T., E-mail: trivera@ipn.mx [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Av. Legaria 694, Col. Irrigacion, 11500 Mexico D. F. (Mexico)

2011-10-15

The dosimetry by thermoluminescence (Tl) is applied in the entire world for the dosimetry of ionizing radiations specially to personal and medical dosimetry. This dosimetry method has been very interesting for measures in vivo because the Tl dosimeters have the advantage of being very sensitive in a very small volume and they are also equivalent to tissue and they do not need additional accessories (for example, cable, electrometer, etc.) The main characteristics of the diverse Tl materials to be used in the radiation measures and practical applications are: the Tl curve, the share homogeneity, the signal stability after the irradiation, precision and exactitude, the response in function with the dose and the energy influence. In this work a brief summary of the advances of the radiations dosimetry is presented by means of the thermally stimulated luminescence and its application to the dosimetry in radiotherapy. (Author)

The combined application of PIXE analysis and thermoluminescence (TL) dating for elucidating the origin of iron manufacturing in Japan

International Nuclear Information System (INIS)

Hagihara, N.; Miono, S.; Chengzhi, Z.; Nakayama, Y.; Hanamoto, K.; Manabe, S.

1999-01-01

For elucidating the origin of iron manufacturing in Japan, the usefulness of PIXE analysis was reconfirmed and a new technique of thermoluminescence (TL) dating was applied. Through reproducing experiments of iron manufacturing and forging, PIXE analysis was tested for classifying the iron slag produced from these two different process. The TL dating method was improved for experiments with the iron manufacturing furnace, burnt at high temperature (about 1300 K) and irradiated with relatively low dose. Utilizing PIXE analysis, the iron manufacturing furnace can be distinguished from the older forging furnace used for the imported iron plate. Adopting TL dating, the oldest iron manufacturing furnace can be found out. Some ancient samples in Japan were used as a test of this combined application, and the results were positive, thus proving the suitability of the method

Thermoluminescence dosimetry environmental monitoring system

International Nuclear Information System (INIS)

Bortoluzzi, S.

1989-01-01

In this report, characteristics and performances of an environmental monitoring system with thermoluminescence dosimetry are presented. Most of the work deals with the main physical parameters necessary for measurements of ambiental dose. At the end of this report some of level doses in the environment around the site of the ENEA Center of Energy Research Salluggia (Italy) are illustrated

Thermoluminescent dosimetry of new phosphors of Zn O exposed to beta radiation

International Nuclear Information System (INIS)

Cruz V, C.; Burruel I, S.E.; Grijalva M, H.; Barboza F, M.; Bernal, R.

2004-01-01

In this work, we report the thermoluminescence dosimetry of a new Zn O phosphor obtained by annealing of Zn S powder precipitated when Zn S films were grown by employing a CBD method. The collected Zn S powder was pressed in a die to form pellets which were subjected to different thermal treatments under air atmosphere. X-ray diffraction (XRD) patterns and energy-dispersive X-ray Spectrometry (EDS) analyses confirmed the transformation of Zn S to Zn O. The phosphors thus obtained were exposed to high doses of beta radiation and their thermoluminescent dosimetry show that these new phosphors are materials suitable to be used in high dose thermoluminescence dosimetry. (Author)

Thermoluminescence of rare earth doped BaSO/sub 4/ phosphors and its applications

Energy Technology Data Exchange (ETDEWEB)

Nagpal, J.S.; Varadharajan, G. (Bhabha Atomic Research Centre, Bombay (India). Div. of Radiological Protection)

1982-03-01

Thermoluminescence of synthetic BaSO/sub 4/ samples individually doped with Y, La, Ce, Pr, Nd, Sm, Eu, Tb, Dy and Tm has been studied after ..gamma..- and microwave irradiations. BaSO/sub 4/:Eu has the highest response for ..gamma..-radiation while BaSO/sub 4/:Tb exhibits highest reduction in its ..gamma..-induced TL after exposure to microwave radiation (2425 +- 25 MHz). The reduction depends on the microwave radiant exposure and is independent of the irradiance level in the range 25-200 mW . cm/sup -2/ and hence can be useful for microwave dosimetry.

Thermoluminescence of magnesium doped zirconium oxide (ZrO2:Mg) UV irradiated

International Nuclear Information System (INIS)

Rivera Montalvo, Teodoro; Furetta, Claudio

2008-01-01

Full text: The monitoring of ultraviolet radiation (UVR) different thermoluminescent (TL) materials have been used to measure UVR. UV dosimetry using thermoluminescence phenomena has been suggested in the past by several authors. This technique has an advantage over others methods due to the readout of the samples. Other advantages of these phosphors are their small size, portability, lack of any power requirements, linear response to increasing radiation dose and high sensitivity. Zirconium oxide, recently received full attention in view of their possible use as thermoluminescent dosimeter (TLD), if doped with suitable activators, in radiation dosimetry. In the present investigation thermoluminescent (TL) properties of magnesium doped zirconium oxide (ZrO 2 :Mg) under ultraviolet radiation (UVR) were studied. The ZrO 2 :Mg powder of size 30-40 nm, having mono clinical structure, exhibit a thermoluminescent glow curve with one peak centered at 180 C degrees. The TL response of ZrO 2 :Mg as a function ultraviolet radiation exhibits four maxima centered at 230, 260, 310 and 350 nmn. TL response of ZrO 2 :Mg as a function of spectral irradiance of UV Light was linear in a wide range. Fading and reusability of the phosphor were also studied. The results showed that ZrO 2 :Mg nano powder has the potential to be used as a UV dosemeter in UVR dosimetry. (author)

Analysis of the thermoluminescent signal in the hydroxyapatite synthesized by the sol-gel method; Analisis de la senal termoluminiscente en la hidroxiapatita sintetizada por el metodo sol gel

Energy Technology Data Exchange (ETDEWEB)

Mendoza A, D.; Gonzalez, P.R. [ININ, A.P. 18-1027, 11801 Mexico D.F. (Mexico); Lobato, M.; Rubio, E.; Rodriguez L, V. [Fac. de Ingenieria Quimica, BUAP, Av. San Claudio y 18 Sur, Col. San Manuel, 72570 Puebla (Mexico); Custodio, E. [Universidad Juarez Autonoma de Tabasco, DACB, Carr. Cunduacan-Jalpa Km. 1.5, 86680 Tabasco (Mexico)

2004-07-01

The physical properties of the ceramics are related with the chemical bonds and the crystalline structure, because the elements that constitute it can be united by ionic bonds or partially ionic giving a covalent character, this last causes that the outer layer is full of electrons. This property makes that the ceramic ones become interesting materials for thermoluminescent applications, as it demonstrates through the recent works presented on the hydroxyapatite that is a ceramic biomaterials that has shown an interesting thermoluminescent signal when being exposed to gamma radiation. In this sense, this work presents the thermoluminescent signal analysis induced by the UV and gamma radiation in a particular type of hydroxyapatite synthesized by sol gel method in which the temperature synthesis is varied. The final thermoluminescent sensitivity of materials is correlated with the crystalline degree, which is analysed through X-ray diffraction. (Author)

On the thermoluminescent interactive multiple-trap system (IMTS) model: is it a simple model?

International Nuclear Information System (INIS)

Gil T, M. I.; Perez C, L.; Cruz Z, E.; Furetta, C.; Roman L, J.

2016-10-01

In the thermally stimulated luminescence phenomenon, named thermoluminescence (Tl), the electrons and holes generated by the radiation-matter interaction can be trapped by the metastable levels in the band gap of the solid. Following, the electron can be thermally releases into the conduction band and a radiatively recombination with hole close to the recombination center occurred and the glow curve is emitted. However, the complex mechanism of trapping and thermally releases occurred in the band gap of solid. Some models, such as; first, second and general-order kinetics, have been well established to explain the behaviour of the glow curves and their defects recombination mechanism. In this work, expressions for and Interactive Multiple-Trap System model (IMTS) was obtained assuming: a set of discrete electron traps (active traps At), another set of thermally disconnected trap (TDT) and a recombination center (Rc) too. A numerical analysis based on the Levenberg-Marquardt method in conjunction with an implicit Rosenbrock method was taken into account to simulate the glow curve. The numerical method was tested through synthetic Tl glow curves for a wide range of trap parameters. The activation energy and kinetics order were determined using values from the General Order Kinetics (GOK) model as entry data to IMTS model. This model was tested using the experimental glow curves obtained from Ce or Eu-doped MgF 2 (LiF) polycrystals samples. Results shown that the IMTS model can predict more accurately the behavior of the Tl glow curves that those obtained by the GOK modified by Rasheedy and by the Mixed Order Kinetics model. (Author)

Computerized glow curve deconvolution of thermoluminescent emission from polyminerals of Jamaica Mexican flower

Science.gov (United States)

Favalli, A.; Furetta, C.; Zaragoza, E. Cruz; Reyes, A.

The aim of this work is to study the main thermoluminescence (TL) characteristics of the inorganic polyminerals extracted from dehydrated Jamaica flower or roselle (Hibiscus sabdariffa L.) belonging to Malvaceae family of Mexican origin. TL emission properties of the polymineral fraction in powder were studied using the initial rise (IR) method. The complex structure and kinetic parameters of the glow curves have been analysed accurately using the computerized glow curve deconvolution (CGCD) assuming an exponential distribution of trapping levels. The extension of the IR method to the case of a continuous and exponential distribution of traps is reported, such as the derivation of the TL glow curve deconvolution functions for continuous trap distribution. CGCD is performed both in the case of frequency factor, s, temperature independent, and in the case with the s function of temperature.

Dosimetric Characteristics of a LKB:Cu,Mg Solid Thermoluminescence Detector

International Nuclear Information System (INIS)

Alajerami Yasser Saleh Mustafa; Hashim Suhairul; Ramli Ahmad Termizi; Saleh Muneer Aziz; Kadir Ahmad Bazlie Bin Abdul; Saripan, Mohd. Iqbal

2013-01-01

We present the main thermoluminescence characteristics of a newly borate glass dosimeter modified with lithium and potassium carbonate (LKB) and co-doped with CuO and MgO. An enhancement of about three times has been shown with the increment of 0.1mol% MgO as a co-dopant impurity. The effects of dose linearity, storage capacity, effective atomic number and energy dose response are studied. The proposed dosimeter shows a simple glow curve, good linearity up to 10 3 Gy, close effective atomic number and photon energy independence. The current results suggest using the proposed dosimeter in different dosimetric applications

Detection and thermoluminescence of coriander (Coriandrum sativum L.) irradiated with 60Co

International Nuclear Information System (INIS)

Ruiz G, B.; Cruz Z, E.; Barboza F, M.

2009-10-01

The fresh and dried coriander (Coriandrum sativum L.) is a spice of high commercial value as food for consumption in Mexico. Their hygienic quality is often poor due to some factors: contaminants present in irrigation water and the cultivation atmosphere, harvesting and post harvest handling, mainly. The process by radiation is an alternative to achieve the sterilization to adequate dose for the hygienic quality for its consumption. However, irradiation also involves food detection exposed to radiation. This paper presents detected results on the dried coriander that was obtained from fresh samples and thermoluminescent properties such as glow curves structure from low doses (0.5 Gy) to high (15 kGy), the dose response, thermoluminescent signal decay, in order to determine the loss of stability during the storage of the poly mineral fraction. We obtained the inorganic fraction separation of the organic part of particle sizes of 10 μm by the Zimmerman method. The samples were exposed at two dose ranges; 0.5-400 Gy and 0.5-15 kGy of gamma radiation with 60 Co. The limit of thermoluminescent detection of the irradiated coriander samples was from 1 Gy. The glow curves were at a broad band of 35-400 C, with a maximum thermoluminescence around 182-196 C, and run at 164 C for high doses of 15 kGy. The range of linear response to dose was 4-25 Gy, whereas higher doses than the kGy order the response increase with the dose. The thermoluminescent properties of the coriander poly mineral fraction, show it can be used to identify irradiated food at gamma doses relatively low and even in doses of commercial interest due to the high stability of thermoluminescent signals. (Author)

Study of thermoluminescence and semiconductors in dosimetry. Application of dosimetry of the whole body in view of bone marrow grafting

International Nuclear Information System (INIS)

Naudy, Suzanne.

1981-05-01

From this study one deduces that thermoluminescence remains the moss reliable process for the measurement of dose in vivo: precision, reproducibility and easy calibration. The semiconductors do not present the quality needed to a reliable use in dosimetry. The limits of each techniques have been established in our study, we have applied them simultaneously in dosimetric irradiations of the whole body in view of bone marrow grafting. Semiconductors allow to follow the irradiation and to intervene instantaneously if necessary, thermoluminescent dosimeter insure precise knowledge of the delivered dose. One hundred and ten patients have been treated before bone narrow grafting at the Gustave Roussy Institut and fifty two of them render account of the results obtained with this experimental dosimetric protocol [fr

Study on carbonated hydroxyapatite as a thermoluminescence dosimeter

International Nuclear Information System (INIS)

Shafaei, M.; Sardari, D.; Ziaie, F.; Larijani, M.M.

2015-01-01

In this study, carbonated hydroxyapatite nanoparticles were used for thermoluminescence dosimetry. The nano-structure carbonated hydroxyapatite synthesized via hydrolysis of CaHPO 4 and CaCO 3 . The obtained nano powders were characterized by XRD technique and FTIR spectroscopy system. The carbonated hydroxyapatite samples were irradiated at different doses using 60 Co gamma rays, and were subjected to thermoluminescence measurement system, consequently. The TL glow curve exhibited two distinguishable peaks centered at around of 165 C and 310 C. The TL response of carbonated hydroxyapatite samples as a function of absorbed dose was linear in the range of 25-1000 Gy. Other dosimetric features of the carbonated hydroxyapatite nanoparticles including fading and reproducibility were also investigated.

Report on the results of the third intercomparison study of thermoluminescent dosimeters for environmental measurements

International Nuclear Information System (INIS)

Driscoll, C.M.H.

1988-01-01

Scientific laboratories within the Member States of the European Communities have a continuing interest in the use and development of both thermoluminescent dosimeters and thermoluminescence measurement techniques for the assessment of exposure from environmental gamma radiation. In the United Kingdom, for example, environmental thermoluminescent dosimeters have been developed by the National Radiological Protection Board (NRPB) and used in a national survey of indoor radiation exposure. Other laboratories in various Member States are currently involved in similar studies of natural radiation exposure or are using thermoluminescent dosimeters for environmental measurements at reactor sites. Therefore, it is appropriate that such laboratories have facilities within the European Community for standardization and intercomparison of their environmental measurement techniques

Thermoluminescent response of Y{sub 2}O{sub 3}:Ce,Eu irradiated with X-rays; Respuesta termoluminiscente del Y{sub 2}O{sub 3}:Ce,Eu irradiado con rayos X

Energy Technology Data Exchange (ETDEWEB)

Sanchez J, F. del R. [Universidad APEC, Escuela de Ingenieria, Apdo. Postal No. 2867, 10107 Santo Domingo (Dominican Republic); Sosa A, M. A., E-mail: sanchezjaquez@gmail.com [Universidad de Guanajuato, Division de Ciencias e Ingenierias, Campus Leon, 37670 Leon, Guanajuato (Mexico)

2017-10-15

The thermoluminescent response of various materials has been studied when irradiated with X-rays, and the parameters that characterize the order of the kinetics of the material, depth of traps and frequency have been determined. The objective of this project was to characterize the thermoluminescent response of dosimeters based on yttrium oxide (Y{sub 2}O{sub 3}) irradiated with X-rays. To do this, the thermoluminescent response of the Y{sub 2}O{sub 3}:Ce,Eu dosimeter was measured and exposed to an X-ray radiation field; five levels of radiation were used: in the first, a potential of 53.5 kv was used and a working load of 5.6 m As, in the second: 70.0 kv, 12.5 m As; in the third: 81.0 kv, 20.0 m As; in the fourth: 109 kv, 32 m As, in the fifth: 121 kv, 80.0 m As, applying an exposure range between 17.7 and 40 R. The irradiation was performed exposing the sample at 104 cm from the focus of the X-ray tube. To obtain the readings of the thermoluminescent response, a Harshaw TLD 3500 reader was used. The data captured by the reader was processed using the WinREMS software. The deletion protocol was as follows: the dosimeters already read were placed, one hour in the Terlab MA12D muffle at a temperature of (400 ± 1) degrees centigrade, the dosimeters were removed and left at room temperature of 20 degrees centigrade for 20 minutes. Then they were placed in the Binder high temperature oven ED23 at 100 ± 1 centigrade degrees for 2 hours. The brightness curves were de convolved using the WebPlotDigitizer v 3.8 software and the individual peaks of the brightness curves were obtained. We found that: the synthesized materials presented a good thermoluminescent response when irradiated with X-rays. However, only one of the dosimeters, of Yttrium oxide doped with 0.5% Cerium, showed a relatively linear response in the applied dose range. The analysis made to the brightness curve of the Yttrium oxide doped with Cerium at 0.5%, applying the method of the three points for the

Photoluminescence and thermoluminescence properties of BaGa2O4

Science.gov (United States)

Noto, L. L.; Poelman, D.; Orante-Barrón, V. R.; Swart, H. C.; Mathevula, L. E.; Nyenge, R.; Chithambo, M.; Mothudi, B. M.; Dhlamini, M. S.

2018-04-01

Rare-Earth free luminescent materials are fast becoming important as the cost of rare earth ions gradually increases. In this work, a Rare-Earth free BaGa2O4 luminescent compound was prepared by solid state chemical reaction, which was confirmed to have a single phase by X-ray Diffraction. The Backscattered Electron image and Energy Dispersive X-ray spectroscopy maps confirmed irregular particle and homogeneous compound formation, respectively. The Photoluminescence spectrum displayed broad emission between 350 to 650 nm, which was deconvoluted into two components. The photoluminescence excitation peak was positioned at 254 nm, which corresponds with the band-to-band position observed from the diffuse reflectance spectrum. The band gap was extrapolated to 4.65 ± 0.02 eV using the Kubelka-Munk model. The preliminary thermoluminescence results indicated that the kinetics involved were neither of first nor second order. Additionally, the activation energy of the electrons within the trap centres was approximated to 0.61 ± 0.01 eV using the Initial Rise model.

Trap characterization by photo-transferred thermoluminescence in MgO nanoparticles

Science.gov (United States)

Isik, M.; Gasanly, N. M.

2018-05-01

Shallow trapping centers in MgO nanoparticles were characterized using photo-transferred thermoluminescence (TL) measurements. Experiments were carried out in low temperature range of 10-280 K with constant heating rate. Shallow traps were filled with charge carriers firstly by irradiating the sample at room temperature using S90/Y90 source and then illuminating at 10 K using blue LED. TL glow curve exhibited one peak around 150 K. Curve fitting analyses showed that this peak is composed of two individual peaks with maximum temperatures of 149.0 and 155.3 K. The activation energies of corresponding trapping centers were revealed as 0.70 and 0.91 eV. The dominant mechanism for TL process was found as second order kinetics which represent that fast retrapping is effective transitions taking place within the band gap. Structural characterization of MgO nanoparticles were investigated using x-ray diffraction, scanning electron microscopy and Fourier transform infrared spectroscopy measurements. Analyses of experimental observations indicated that MgO nanoparticles show good crystallinity with particle size in nanometer scale.

Assessment of CaSO4:Dy and LiF:Mg,Ti thermoluminescent dosimeters performance in the dosimetry of clinical electron beams

International Nuclear Information System (INIS)

Nunes, Maira Goes

2008-01-01

The assessment of the performance of CaS0 4 :Dy thermoluminescent detectors produced by IPEN in the dosimetry of clinical electron beams aims to propose an alternative to the LiF:Mg,Ti commercial dosimeters (TLD-100) largely applied in radiation therapy. The two types of thermoluminescent dosimeters were characterised with the use of PMMA, RMI-457 type solid water and water phantoms in radiation fields of 4, 6, 9, 12 and 16 MeV electrons of nominal energies in which the dose-response curves were obtained and the surface and depth doses were determined. The thermoluminescent response dependency with the electron nominal energies and the applied phantom were studied. The CaS0 4 :Dy presented the same behaviour than the LiF:Mg,Ti in such a way that its application as an alternative to the TLD-100 pellets in the radiation therapy dosimetry of electron beams is viable and presents the significantly higher sensitivity to the electron radiation as its main advantage. (author)

Effect of particle size on the thermoluminescent response of hydroxyapatite

International Nuclear Information System (INIS)

Barrera V, A.; Zarate M, J.; Contreras, M. E.; Rivera M, T.

2016-10-01

We present the study of the structural characterization and the thermoluminescent response of the hydroxyapatite as a function of the calcination temperature and the effect of the particle size. For precipitation synthesis, calcium nitrate (Ca(NO_3)_2 and dibasic ammonium phosphate ((NH_4)_2HPO_4) were used as precursors and ammonium hydroxide (NH_4OH) as a ph controlling agent. The characterization of the samples was carried out by the techniques of X-ray diffraction, scanning electron microscopy and infrared spectroscopy. The powders obtained are composed of hydroxyapatite, with a different degree of dehydroxylation. The thermoluminescent characterization indicates that at higher calcination temperature there is a higher thermoluminescent response, the calcined powders at 1300 degrees Celsius show a very well defined brightness curve with a higher intensity, with its maximum intensity located at a temperature of 210 degrees Celsius, which indicates that this material can be used as a dosimeter. (Author)

Thermoluminescence in HfO{sub 2}:Eu{sup 3+} powders irradiated in UV; Termoluminiscencia en polvos de HfO{sub 2}:Eu{sup 3+} irradiados en el UV

Energy Technology Data Exchange (ETDEWEB)

Ceron R, P. V. [Universidad de Guanajuato, Division de Ciencias e Ingenierias, Loma del Bosque No. 103, Col. Lomas del Campestre, 37150 Leon, Guanajuato (Mexico); Montes R, E.; Rivera M, T.; Diaz G, J. A. I.; Guzman M, J. [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Unidad Legaria, Av. Legaria 694, Col. Irrigacion, 11500 Ciudad de Mexico (Mexico)

2016-10-15

Various inorganic compounds synthesized for photo luminescent applications have also presented a thermoluminescent (Tl) response, for example the metal oxides doped with rare earths. This property extends the use of these materials to the radiation dosimetry. For this reason, in this work the Tl response is presented in HfO{sub 2}:Eu{sup 3+} powders synthesized by the hydrothermal path, exposed to ultraviolet (UV) radiation of 254 nm. The kinetic parameters of its brightness curve were also calculated using the Chen expressions and the analysis method based on the shape of the curve. For the powders irradiated for 10 min the highest Tl response corresponds to the sample with 5% of the impurity, which is 6.5 times higher than the signal corresponding to the intrinsic sample. Its bright curve shows a main peak with a maximum in 148 degrees Celsius and a second order kinetics. Another test with the same material shows the Tl response against the exposure time, with a maximum in the 3 minutes. These calculations and tests constitute a first approach for the study of these powders as Tl dosimeter for UV radiation. (Author)

The application of thermoluminescent dosimeters to the measurement of thermal neutron distributions in bulk media

International Nuclear Information System (INIS)

Bubb, I.F.; Tang, J.C.N.

1981-01-01

The work described was designed to investigate the suitability of measuring neutron flux distributions in bulk media using neutron sensitive thermoluminescent dosimeters, with the initial interest being in wet coal matrices. The phosphors used were 6 LiF and 7 LiF 3.2mmx3.2mmx0.9mm chips. As 7 LiF is sensitive to gamma rays only it was used to correct for the gamma-ray response of 6 LiF

Thermoluminescence response of the poly mineral fraction from hibiscus sabdariffa L foodstuffs

International Nuclear Information System (INIS)

Cruz Z, E.; Guzman, S.; Brown, F.; Chernov, V.; Barboza F, M.

2011-01-01

Food processed by ionizing irradiation is a safe technology and has been recognized by the FAO/Who Codes Alimentarius Commission. It is an excellent method to prevent food spoilage and food borne diseases by inhibiting the growth of microorganisms and slowing down ripening. The widespread use of food irradiation treatments that include spices, dry vegetables, grains and fruits make relevant the developing of methods for identification and analyses of foodstuffs processed by irradiation. The present work focuses on the thermoluminescence property of Mexican Roselle flower previously irradiated for detection purposes. The poly mineral content of irradiated commercial Roselle flower (Hibiscus sabdariffa L.) was extracted and analyzed by thermoluminescence (Tl). The X-ray diffraction analyses showed that quartz and albite composition for the poly mineral fraction. Different grain sizes; 10, 53, 74 and 149 μm, were selected for the Tl analyses. The Tl glow curves depended on the grain sizes. The glow curves depicted two peaks around 92 and 120 C. The first peak was ascribed to quartz and the broad part of the glow curves (120-250 C) seems to correspond to the albite. Because the complex structure of the Tl glow curves from poly minerals the kinetic parameters were calculated by a fitting process using a deconvolution method based on a non-linear least-squares Levenberg-Ma quart. The values of the activation energy were found to be at 0.79-1.05 eV and 0.79-1.04 for 53 μm and 250 μm, respectively. The Tl properties of the samples were determined including dose response, reproducibly, fading and UV light bleaching. (Author)

Thermoluminescence response of the poly mineral fraction from hibiscus sabdariffa L foodstuffs

Energy Technology Data Exchange (ETDEWEB)

Cruz Z, E.; Guzman, S. [UNAM, Instituto de Ciencias Nucleares, Apdo. Postal 70-543, 04510 Mexico D. F. (Mexico); Brown, F. [Universidad de Sonora, Departamento de Investigacion en Polimeros y Materiales, Apdo. Postal 130, 83000 Hermosillo, Sonora (Mexico); Chernov, V.; Barboza F, M., E-mail: ecruz@nucleares.unam.m [Universidad de Sonora, Departamento de Investigacion en Fisica, Apdo. Postal 5-088, 83190 Hermosillo, Sonora (Mexico)

2011-02-15

Food processed by ionizing irradiation is a safe technology and has been recognized by the FAO/Who Codes Alimentarius Commission. It is an excellent method to prevent food spoilage and food borne diseases by inhibiting the growth of microorganisms and slowing down ripening. The widespread use of food irradiation treatments that include spices, dry vegetables, grains and fruits make relevant the developing of methods for identification and analyses of foodstuffs processed by irradiation. The present work focuses on the thermoluminescence property of Mexican Roselle flower previously irradiated for detection purposes. The poly mineral content of irradiated commercial Roselle flower (Hibiscus sabdariffa L.) was extracted and analyzed by thermoluminescence (Tl). The X-ray diffraction analyses showed that quartz and albite composition for the poly mineral fraction. Different grain sizes; 10, 53, 74 and 149 {mu}m, were selected for the Tl analyses. The Tl glow curves depended on the grain sizes. The glow curves depicted two peaks around 92 and 120 C. The first peak was ascribed to quartz and the broad part of the glow curves (120-250 C) seems to correspond to the albite. Because the complex structure of the Tl glow curves from poly minerals the kinetic parameters were calculated by a fitting process using a deconvolution method based on a non-linear least-squares Levenberg-Ma quart. The values of the activation energy were found to be at 0.79-1.05 eV and 0.79-1.04 for 53 {mu}m and 250 {mu}m, respectively. The Tl properties of the samples were determined including dose response, reproducibly, fading and UV light bleaching. (Author)

Thermoluminescence properties of irradiated commercial color pencils for accidental retrospective dosimetry

International Nuclear Information System (INIS)

Meriç, Niyazi; Şahiner, Eren; Bariş, Aytaç; Polymeris, George S.

2015-01-01

Color pencils are widely used mostly in kindergartens, in schools and could be found in all houses with families having young children. Their wide spread use in modern times as well as their chemical composition, consisting mostly of Si and Al, constitute two strong motivations towards exploiting their use as accidental retrospective thermoluminescent dosimeters. The present manuscript reports on the study of colored pencils manufactured by a commercial brand in China which is very common throughout Turkey. The preliminary results discussed in the present work illustrated encouraging characteristics, such as the presence of a trapping level giving rise to natural TL in a temperature range that is sufficiently high. Specific thermoluminescence features of this peak, such as glow peak shape and analysis, anomalous fading, thermal quenching, reproducibility, linearity and recovery ability to low attributed doses were studied. The results suggest that the color pencils could be effectively used in the framework of retrospective thermoluminescent dosimetry with extreme caution, based on multiple aliquot protocols. - Highlights: • Thermoluminescence of the inner part of commercial colored pencils was studied. • The presence of a trapping level giving rise to natural TL at 260 °C was yielded. • Deco analysis, anomalous fading, thermal quenching, reproducibility, linearity and recovery ability of this peak were studied

Fast neutron dosimetry using CaSO4:Dy thermoluminescent dosimeters

International Nuclear Information System (INIS)

Azorin, N.G.; Salvi, C.R.; Rubio, J.L.; Gutierrez, C.A.

1980-01-01

The use of CaSO 4 :Dy phosphor powder in fast neutron dose measurements using the activation of sulphur from the 32 S(n,p) 32 P reaction is described. The thermoluminescence induced during the irradiation and that due to the decay of short-lived activation products, is erased by annealing the dosimeters after a post-irradiation time of 3 days. The self-induced thermoluminescence measured at different intervals of post-irradiation time, gives an estimation of the fast neutron dose to which the dosimeters were exposed

Thermoluminescence dosimeters with narrow bandpass filters

Science.gov (United States)

Walker, Scottie W.

2004-07-20

A dosimetry method exposes more than one thermoluminescence crystals to radiation without using conventional filters, and reads the energy stored in the crystals by converting the energy to light in a conventional manner, and then filters each crystal output in a different portion of the spectrum generated by the crystals.

Rare earth oxyhalogenide base thermoluminescent material

International Nuclear Information System (INIS)

Rabatin, J.G.

1976-01-01

A process is described that consists to expose a thermoluminescent material to ionizing radiations, the material being a rare earth oxyhalogenide with terbium additions, to heat this material up to the emission of visible radiations and to measure the emitted radiations which are proportional to the ionizing radiation dose [fr

Photoluminescence, trap states and thermoluminescence decay ...

Indian Academy of Sciences (India)

Administrator

Photoluminescence, trap states and thermoluminescence decay process study of Ca2MgSi2O7 : Eu. 2+. , Dy. 3+ phosphor. RAVI SHRIVASTAVA*, JAGJEET KAUR, VIKAS DUBEY and BEENA JAYKUMAR. Govt. VYT PG Autonomous College, Durg 491 001, (C.G.) India. MS received 9 July 2013; revised 5 December 2013.

Thermoluminescent response of aluminium oxide thin films subject to gamma irradiation

Energy Technology Data Exchange (ETDEWEB)

Arrieta, A.; Escobar A, L.; Camps, E.; Villagran, E.; Gonzalez, P.R

2006-07-01

The thermoluminescent (TL) properties of amorphous aluminium oxide thin films (thicknesses as low as 0.3 {mu}m) subjected to gamma (Co-60) irradiation are reported. Aluminium oxide thin films were prepared by laser ablation from an Al{sub 2}O{sub 3} target using a Nd: YAG laser with emission at the fundamental line. The films were exposed to gamma radiation (Co-60) in order to study their TL response. Thermoluminescence glow curves exhibited two peaks at 110 and 176 C. The high temperature peak shows good stability and 30% fading in the first 5 days after irradiation. A linear relationship between absorbed dose and the thermoluminescent response for doses span from 150 mGy to 100 Gy was observed. These results suggest that aluminium oxide thin films are suitable for detection and monitoring of gamma radiation. (Author)

Eu{sup 2+} doped TiO{sub 2} nano structures synthesized by HYSYCVD for thermoluminescence dosimetry

Energy Technology Data Exchange (ETDEWEB)

Perez A, J. A. [Universidad de Sonora, Departamento de Fisica, Apdo. Postal 5-088, 83000 Hermosillo, Sonora (Mexico); Leal C, A. L.; Melendrez A, R.; Barboza F, M., E-mail: alanix89@gmail.com [Universidad de Sonora, Departamento de Investigacion en Fisica, Apdo. Postal 5-088, 83000 Hermosillo, Sonora (Mexico)

2016-10-15

Titania (TiO{sub 2}) has attracted interest owing his potential applications as dosimetry material given his excellent optical, electrical and thermal properties and the ability to shape his structure make TiO{sub 2} suitable for research and dosimetry applications. In this work, a systematic study to know the magnitude of processing parameters influence on thermoluminescent properties of undoped (TiO{sub 2}) and doped (TiO{sub 2}:Eu{sup 2+}) nano materials obtained by hybrid precursor systems chemical vapor deposition (HYSYCVD) technique is presented. Synthesis of one dimension nano structures of TiO{sub 2}:Eu{sup 2+} was carried out using K{sub 2}TiF{sub 6} and EuCl{sub 2} as dopant at 0.5, 1, 2.5 and 5 wt %. The nano structures samples were irradiated with β-ray in a doses range of 0.083-3000 Gy. All thermoluminescence (Tl) glow curves showed 3 broad Tl peaks around 373, 473 and 573 K, and a dosimetric linear behavior from 0.083 to 300 Gy. The Tl has a good reproducibility, with deviations of around 5%, making these TiO{sub 2}:Eu{sup 2+} nano materials suitable for dosimetric applications. (Author)

Study of a new glass matrix by the thermoluminescence technique

International Nuclear Information System (INIS)

Ferreira, Pamela Z.; Vedovato, Uly P.; Cunha, Diego M. da; Dantas, Noelio O.; Silva, Anielle C.A.; Neves, Lucio P.; Perini, Ana P.; Carrera, Betzabel N.S.; Watanabe, Shigueo

2015-01-01

The thermoluminescence technique is widely used for both personal and for high-dose dosimetry. In this work, the thermoluminescence technique was utilized to study a new glass matrix, with nominal composition of 20Li 2 CO 3 .10Al 2 O 3 .20BaO.50B 2 O 3 (mol%), irradiated with different doses in a 60 Co source. The glow curves and the dose-response curve were obtained for radiation doses between 50 Gy and 900 Gy. The results showed that this new glass matrix presents potential use in high-dose dosimetry. (author)

On the thermoluminescent interactive multiple-trap system (IMTS) model: is it a simple model?

Energy Technology Data Exchange (ETDEWEB)

Gil T, M. I.; Perez C, L. [UNAM, Facultad de Quimica, Ciudad Universitaria, 04510 Ciudad de Mexico (Mexico); Cruz Z, E.; Furetta, C.; Roman L, J., E-mail: ecruz@nucleares.unam.mx [UNAM, Instituto de Ciencias Nucleares, Ciudad Universitaria, 04510 Ciudad de Mexico (Mexico)

2016-10-15

In the thermally stimulated luminescence phenomenon, named thermoluminescence (Tl), the electrons and holes generated by the radiation-matter interaction can be trapped by the metastable levels in the band gap of the solid. Following, the electron can be thermally releases into the conduction band and a radiatively recombination with hole close to the recombination center occurred and the glow curve is emitted. However, the complex mechanism of trapping and thermally releases occurred in the band gap of solid. Some models, such as; first, second and general-order kinetics, have been well established to explain the behaviour of the glow curves and their defects recombination mechanism. In this work, expressions for and Interactive Multiple-Trap System model (IMTS) was obtained assuming: a set of discrete electron traps (active traps At), another set of thermally disconnected trap (TDT) and a recombination center (Rc) too. A numerical analysis based on the Levenberg-Marquardt method in conjunction with an implicit Rosenbrock method was taken into account to simulate the glow curve. The numerical method was tested through synthetic Tl glow curves for a wide range of trap parameters. The activation energy and kinetics order were determined using values from the General Order Kinetics (GOK) model as entry data to IMTS model. This model was tested using the experimental glow curves obtained from Ce or Eu-doped MgF{sub 2}(LiF) polycrystals samples. Results shown that the IMTS model can predict more accurately the behavior of the Tl glow curves that those obtained by the GOK modified by Rasheedy and by the Mixed Order Kinetics model. (Author)

Thermoluminescence study of quartzite in a gold and uranium mineralized zone (Canavieiras, Jacobina-Bahia)

International Nuclear Information System (INIS)

Ferreira, J.

1973-01-01

The quartzite of Canavieiras gold mine (Jacobina-Bahia, Brazil) shows in its natural glow curve, a high temperature. The study of the reproductibility of this peak resulted in the standartization of measurement for grain sizes between 80 and 100 mesh. ''In Situ'' total gamma-ray profiles were made using a scintillation detector for the study the distribution of radioactive elements near the pirite, uranium and gold strike. In the interpretation of the profiles it was possible to shown a positive correlation between thermoluminescence and uranium yields. The thermoluminescence peak is sufficiently high temperature peak to let thermoluminescence accumulate at ambient temperatures. It was used in attempt to estimate the time and the event that enitiated the accumulation of thermoluminescence. The result obtained, (7 - + 4).10 6 years, may correspond to the last heating of the rocks at relatively recent time. (C.D.G.) [pt

Thermoluminescence properties of zinc oxide obtained by solution combustion synthesis

Energy Technology Data Exchange (ETDEWEB)

Orante B, V. R.; Escobar O, F. M.; Cruz V, C. [Universidad de Sonora, Departamento de Investigacion en Polimeros y Materiales, Apdo. Postal 130, 83000 Hermosillo, Sonora (Mexico); Bernal, R., E-mail: victor.orante@polimeros.uson.mx [Universidad de Sonora, Departamento de Investigacion en Fisica, Apdo. Postal 5-088, 83190 Hermosillo, Sonora (Mexico)

2014-08-15

High-dose thermoluminescence dosimetry properties of novel zinc oxide obtained by solution combustion synthesis in a glycine-nitrate process, with a non-stoichiometric value of the elemental stoichiometric coefficient (Φ{sub c}) are presented in this work. Zn O powder samples obtained were annealed afterwards at 900 grades C during 2 h in air. Sintered particles of sizes between ∼ 0.5 and ∼ 2 μm were obtained, according to scanning electron microscopy results. X-ray diffraction indicates the presence of the hexagonal phase of Zn O for the powder samples obtained, before and after thermal annealing, without any remaining nitrate peaks observed. Thermoluminescence glow curves of Zn O obtained after being exposed to beta radiation consists of two maxima; one located at ∼ 149 grades C and another at ∼ 308 grades C, being the latter the dosimetric component of the curve. Dosimetric characterization of non-stoichiometric zinc oxide provided experimental evidence like asymptotic behavior of the Tl signal fading for times greater than 16 h between irradiation and the corresponding Tl readout, as well as the linear behaviour of the dose response without saturation in the dose interval studied (from 12.5 up to 400 Gy). Such characteristics place Zn O phosphors obtained in this work as a promising material for high-dose radiation dosimetry applications (e.g., radiotherapy and food industry). (author)

Effect of thermal decomposition of hydroxyapatite on the thermoluminescent response

International Nuclear Information System (INIS)

Sandoval C, K. J.; Zarate M, J.; Lemus R, J.; Rivera M, T.

2014-08-01

In this work, a study on the thermoluminescence (Tl) induced by gamma radiation in synthetic hydroxyapatite (Hap) annealed at different temperatures obtained by the precipitation method is presented. Synthesis of hydroxyapatite Hap was carried out starting from inorganic precursors [Ca(NO 3 ) 2 ·4H 2 O and (NH 4 ) 2 HPO 4 ]. The precipitate was filtered, washed, dried and then the powder was calcined at different temperatures until the Hap decomposition. The structural and morphological characterization was carried out using both X-ray diffraction (XRD) and scanning electron microscopy (Sem) techniques. Thermoluminescent (Tl) properties of Hap powders were irradiated at different gamma radiation doses. According to X ray diffraction patterns, the tricalcium diphosphate phase (Tcp) appear when the Hap was calcined at 900 grades C. Tl glow curve showed two peaks located at around 200 and 300 grades C, respectively. Tl response as a function of gamma radiation dose was in a wide range from 25 to 100 Gy. The fading of the Tl response at 134 days after irradiation was measured. Experimental results showed that the synthetic hydroxyapatite obtained by precipitation technique may have dosimetric applications when is annealed at temperature of 900 grades C, where the Tcp phase appears and contributes to Tl response, which opens the possibility of using this biomaterials in the area of dosimetry, as they are generally used for biomedical implants. (author)

A preliminary approach to identify irradiated foods by thermoluminescence measurements

International Nuclear Information System (INIS)

Shin, Choonshik; Kim, Hyoung-Ook; Lim, Yoongho

2012-01-01

Thermoluminescence (TL) is one of the physical methods for the identification of irradiated foods. Among the currently developed methods, TL is the most widely used method for the identification of irradiated foods. However, in order to use this method, silicate minerals should be isolated from food samples. The process for the isolation of silicate minerals is time consuming and laborious. In this work, we have investigated the applicability of the TL method using iron-containing minerals instead of silicate minerals. In the TL analyses of dried spices, TL glow curves of iron-containing minerals showed maximum temperatures between 150 and 250 °C which were the same as those of silicate minerals. The process for the mineral separation of the proposed method is simple, fast, easy, and reliable. Moreover, the analysis results including TL ratio have not shown significant differences compared with the silicate minerals method. As a result, the TL measurements using the iron-containing minerals could be an excellent method for the identification of the irradiated foods, including dried spices. - Highlights: ► A thermoluminescence method using iron-containing minerals is proposed. ► Current method using silicate minerals is time consuming and laborious. ► However, the proposed method is simple, fast, easy, and reliable. ► Analysis results are similar to those of the silicate minerals method.

Thermoluminescence properties of zinc oxide obtained by solution combustion synthesis

International Nuclear Information System (INIS)

Orante B, V. R.; Escobar O, F. M.; Cruz V, C.; Bernal, R.

2014-08-01

High-dose thermoluminescence dosimetry properties of novel zinc oxide obtained by solution combustion synthesis in a glycine-nitrate process, with a non-stoichiometric value of the elemental stoichiometric coefficient (Φ c ) are presented in this work. Zn O powder samples obtained were annealed afterwards at 900 grades C during 2 h in air. Sintered particles of sizes between ∼ 0.5 and ∼ 2 μm were obtained, according to scanning electron microscopy results. X-ray diffraction indicates the presence of the hexagonal phase of Zn O for the powder samples obtained, before and after thermal annealing, without any remaining nitrate peaks observed. Thermoluminescence glow curves of Zn O obtained after being exposed to beta radiation consists of two maxima; one located at ∼ 149 grades C and another at ∼ 308 grades C, being the latter the dosimetric component of the curve. Dosimetric characterization of non-stoichiometric zinc oxide provided experimental evidence like asymptotic behavior of the Tl signal fading for times greater than 16 h between irradiation and the corresponding Tl readout, as well as the linear behaviour of the dose response without saturation in the dose interval studied (from 12.5 up to 400 Gy). Such characteristics place Zn O phosphors obtained in this work as a promising material for high-dose radiation dosimetry applications (e.g., radiotherapy and food industry). (author)

Thermoluminescence glow-curve deconvolution functions for mixed order of kinetics and continuous trap distribution

International Nuclear Information System (INIS)

Kitis, G.; Gomez-Ros, J.M.

2000-01-01

New glow-curve deconvolution functions are proposed for mixed order of kinetics and for continuous-trap distribution. The only free parameters of the presented glow-curve deconvolution functions are the maximum peak intensity (I m ) and the maximum peak temperature (T m ), which can be estimated experimentally together with the activation energy (E). The other free parameter is the activation energy range (ΔE) for the case of the continuous-trap distribution or a constant α for the case of mixed-order kinetics

Historical note: thermoluminescent dosimetry (LiF) 1950-51

International Nuclear Information System (INIS)

Heckelsberg, L.F.

1980-01-01

The early history of thermoluminescent dosimetry has not been adequately described and one of the first workers in this field takes this opportunity to record more fully the history of the period. (author)

Effect on thermoluminescence parameters of biotite mineral due to thermal quenching

International Nuclear Information System (INIS)

Kalita, J.M.; Wary, G.

2012-01-01

The Thermally Stimulated Luminescence (TSL) at room temperature X-ray irradiated natural biotite in form of micro-grain powder was studied under various heating rates. TSL peaks showed at temperatures 393 K, 399.6 K, 403.5 K, 404.5 K, 406.9 K at their respective heating rates 2 K/s, 4 K/s, 6 K/s, 8 K/s and 10 K/s. The effect of thermal quenching on thermoluminescence parameters such as peak maximum temperature, peak area, FWHM, geometrical symmetry factor, the activation energy were investigated. From the symmetry factor it is clear that the TL glow curve follows the first order kinetics for the lowest heating rate, but as the heating rate increases it defers from the first order. The activation energies for each heating rates were calculated by using Chen peak shape methods for general order kinetics and found to be decreased for higher heating rates. When activation energy is calculated by variable heating rate method it is observed that the method overestimated the value of activation energy and pre-exponential frequency factor significantly due to thermal quenching. - Highlights: ► Biotite is a common mineral with chemical formula K(Mg,Fe) 3 AlSi 3 O 10 (F,OH) 2 . ► Structural, compositional and elemental analysis of biotite is carried out. ► TSL of X-ray irradiated natural biotite was studied under various heating rates. ► The effect of thermal quenching on TL parameters has been investigated.

Thermoluminescence and electron spin resonance studies of irradiated biological single crystals

International Nuclear Information System (INIS)

Cooke, D.W.

1977-01-01

Single crystals of x-irradiated L-alanine:Cr 3+ have been studied between 90 and 300K by electron spin resonance (ESR) and thermoluminescence (TL) techniques. Ultraviolet (uv) photobleaching of the Cr 3+ electron traps and L-alanine radical centers was also investigated. The results demonstrate that the x-ray generated radical centers can be destroyed by uv-induced electron transport activity, and this destruction follows first order kinetics. Also, the transformation of the primary neutral radical species to a secondary radical in L-alanine was found not to be induced by intermolecular electron transport. The TL glow was determined to proceed by first-order kinetics at a temperature of 160K with an activation energy of 0.3 eV and a frequency factor of 1.0 x 10 8 s -1 . The emission spectrum consisted of a broad band (FWHM approx. = 100 nm) which peaked at approximately 420 nm. Scintillation activity was observed in the ferroelectric crystals triglycine sulfate (TGS), deuterated TGS, and TGS: L-alanine. The emission spectrum of TGS:L-alanine was obtained. New observations of scintillations and current pulses from glycine, a nonferroelectric crystal, which result from heating or cooling the sample between 77 and 300K with no previous irradiation were made. The scintillations and current pulses occur approximately in coincidence. Scintillations were also observed from the potent oncogen 3-hydroxyxanthine by cooling the sample from 300 to 90K with no previous irradiation

Analysis of luminescence from common salt (NaCl) for application to retrospective dosimetry

International Nuclear Information System (INIS)

Spooner, N.A.; Smith, B.W.; Williams, O.M.; Creighton, D.F.; McCulloch, I.; Hunter, P.G.; Questiaux, D.G.; Prescott, J.R.

2011-01-01

Thermoluminescence (TL), Optically-Stimulated Luminescence (OSL) and Infrared-Stimulated Luminescence (IRSL) emitted from a set of 19 salt (NaCl) samples were studied for potential application to retrospective dosimetry. TL emission spectra revealed intense TL emissions from most samples, centred on 590 nm; UV and blue emissions were also found. Significant thermally-induced sensitivity changes were observed and TL, OSL and IRSL growth curves were measured. Pulse anneal analysis was performed, as was quantitative imaging of the TL, OSL and IRSL to assess sample heterogeneity. Kinetic analysis found lifetimes at 20 °C of the 200 °C and 240 °C TL peaks to be 0.6 ka and 4 ka respectively; sufficient for application to retrospective dosimetry.

Hydrothermally synthesized barium fluoride nanocubes for thermoluminescence dosimetry

Energy Technology Data Exchange (ETDEWEB)

Bhadane, Mahesh S.; Dahiwale, S. S.; Bhoraskar, V. N.; Dhole, S. D., E-mail: sanjay@physics.unipune.ac.in [Department of Physics, Savitribai Phule Pune University, Pune-411007 (India)

2016-05-23

In this work, we report a hydrothermally synthesized Dy doped BaF{sub 2} (BaF{sub 2}:Dy) nanocubes and its Thermoluminescence studies. The synthesized BaF{sub 2}:Dy samples was found to posses FCC structure and having average size ~ 60-70 nm, as revealed through X-Ray Diffraction. Cubical morphology having size ~90 nm was observed from TEM analysis. The {sup 60}Co γ- ray irradiated BaF{sub 2}:Dy TL dosimetric experiments shows a pre-dominant single glow peak at 153 °C, indicating a single level trap present as a metastable state. Furthermore, BaF{sub 2}:Dy nanophosphor shows a sharp linear response from 10 Gy to 3 kGy, thus it can be applicable as a gamma dosimeter.

Thermoluminescence study of X-ray irradiated muscovite mineral under various heating rate

International Nuclear Information System (INIS)

Kalita, J.M.; Wary, G.

2014-01-01

The thermoluminescence (TL) glow curves of X-ray irradiated micro-grain natural muscovite were recorded within 298–520 K at various linear heating rates (2 K/s, 4 K/s, 6 K/s, 8 K/s and 10 K/s). Natural TL of muscovite was checked, but no significant TL was observed within 298–520 K in any heating rate. Within the heating rate 2–10 K/s only a low temperature distinct peak was observed in the temperature range 348–357 K. The TL parameters such as activation energy, order of kinetic, geometrical symmetry factor and pre-exponential frequency factor were investigated from the glow peak by Peak Shape (PS) method and Computerized Glow Curve Deconvolution (CGCD) technique. At lowest heating rate the glow peak obeys non-first order kinetic and at the highest heating rate it follows the second order kinetic. The variation of peak integrals, peak maximum temperatures, FWHM and activation energy with heating rates were investigated, and the glow curves at higher rates were found to be influenced by the presence of the thermal quenching. The thermal quenching activation energy and pre-exponential factor were calculated and found to be 2.31±0.02 eV and 3.46×10 14 s −1 , respectively. -- Highlights: • Muscovite is a silicate mineral with chemical formula KAl 2 (Si 3 Al)O 10 (OH,F) 2 . • TL of natural and X-ray induced muscovite was studied under various heating rates. • TL parameters were evaluated by Peak Shape and CGCD method. • Thermal quenching parameters (W and C) of muscovite were evaluated

Thermoluminescence in some copper-doped compounds

International Nuclear Information System (INIS)

Patil, R.R.; Moharil, S.V.; Dhopte, S.M.; Muthal, P.L.; Kondawar, V.K.

2003-01-01

Thermoluminescence (TL) in various Cu + -doped materials is studied. A good correlation between the presence of copper in the Cu + form and TL sensitivity is observed. Correlation between TL emission spectra and photoluminescence suggests that Cu + acts as the emission center in the TL process. (copyright 2003 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Thermoluminescence analysis of co-doped NaCl at low temperature irradiations

Energy Technology Data Exchange (ETDEWEB)

Cruz-Zaragoza, E., E-mail: ecruz@nucleares.unam.m [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, A.P. 70-543, 04510 Mexico D.F. (Mexico); Ortiz, A. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, A.P. 70-543, 04510 Mexico D.F. (Mexico); Unidad Profesional Interdisciplinaria de Ingenieria y Tecnologias Avanzadas, IPN, Av. Instituto Politecnico Nacional 2580, Col. La Laguna Ticoman, 07340 Mexico D.F. (Mexico); Furetta, C. [Touro University Rome, Circne Gianicolense 15-17, 00153 Rome (Italy); Flores J, C.; Hernandez A, J.; Murrieta S, H. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, A.P. 20-364, 01000 Mexico D.F. (Mexico)

2011-02-15

The thermoluminescent response and kinetics parameters of NaCl, doubly activated by Ca-Mn and Cd-Mn ions, exposed to gamma radiation are analyzed. The doped NaCl samples were irradiated at relative low temperature, i.e. at the liquid nitrogen temperature (LNT) and at dry ice temperature (DIT), and the glow curves obtained after 2 Gy of gamma irradiation were analyzed using the computerized glow curve deconvolution (CGCD). An evident variation in the glow curve structure after LNT and DIT was observed. It seems that different kinds of trapping levels are activated at relative low temperature. The original two prominent peaks in compositions A (Ca,Mn) and B (Ca,Mn) have been changed in only one main peak with satellites in the low temperature side of the glow curves. In compositions C (Cd,Mn) and D (Cd,Mn), low temperature peaks become stronger and prominent than the high temperature peaks; this effect could be explained considering that the trapping probability for low temperature traps, the one very close to the conduction band, is enhanced by low temperatures during irradiation.

Irradiated black pepper identification based on thermoluminescence of silicate minerals

International Nuclear Information System (INIS)

Faycal Kharfi; Randa Ketfi

2018-01-01

In this work we have successfully implemented thermoluminescence TL method for irradiated food identification. First tests are performed on Indian black pepper and show promising results to extend the proposed method to many other foods. The X-ray diffraction (XRD) shows that SiO 2 (p3 2 21) is the main component of the separated mineral phase. A saturation dose of ∼ 100 Gy is determined for this pepper above which all thermoluminescent centers of the quartz are activated. Thus, above this threshold dose, only the pepper irradiation will be confirmed but no accuracy on the exact dose received. (author)

Thermoluminescent characteristics of CaSO{sub 4}:Dy+PTFE irradiated with high energy electron beams; Caracteristicas termoluminiscentes del CaSO{sub 4}:Dy+PTFE irradiado con haces de electrones de alta energia

Energy Technology Data Exchange (ETDEWEB)

Alvarez, R.; Rivera, T.; Calderon, J. A.; Jimenez, Y. [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Av. Legaria 694, Col. Irrigacion, 11500 Mexico D. F. (Mexico); Rodriguez, J. [Hospital General de Mexico, Dr. Balmis 148, Col. Doctores, 06726 Mexico D. F. (Mexico); Oviedo, O. [Centro Medico ABC, Sur 136 No. 116, Col. Las Americas, 01120 Mexico D. F. (Mexico); Azorin, J., E-mail: chagua@hotmail.com [Universidad Autonoma Metropolitana, Unidad Iztapalapa, Av. San Rafael Atlixco 186, 09340 Mexico D. F. (Mexico)

2011-10-15

In the present work thermoluminescent response of dysprosium doped calcium sulfate embedded in polytetrafluorethylene (CaSO{sub 4}:Dy+PTFE) under high electron beam irradiations from linear accelerator for clinical applications was investigated. The irradiations were carried out using high electron beams (6 to 18 MeV) from a linear accelerator Varian, C linac 2300C/D, for clinical practice purpose. The electron irradiations were obtained by using the water solid in order to guarantee electronic equilibrium conditions. Field shaping for electron beams was obtained with electron cones. Glow curve and other thermoluminescent characteristics of CaSO{sub 4}:Dy+PTFE were conducted under high electron beams irradiations. The thermoluminescent response of the pellets showed and intensity peak centered at around 235 C. Thermoluminescent response of CaSO{sub 4}:Dy+PTFE as a function of high electron absorbed dose showed a linearity in a wide range. To obtain reproducibility characteristic, a set of pellets were exposed repeatedly for the same electron absorbed dose. The results obtained in this study can suggest the applicability of CaSO{sub 4}:Dy+PTFE pellets for high electron beam dosimetry, provided fading is correctly accounted for. (Author)

Thermoluminescent and optical processes in alkaline halogenides dosemeters contaminated with Europium; Procesos opticos y termoluminiscentes en dosimetros de halogenuros alcalinos contaminados con Europio

Energy Technology Data Exchange (ETDEWEB)

Barboza F, M.; Melendrez, R.; Castaneda, B.; Pedroza M, M.; Chernov, V.; Perez S, R.; Aceves, R. [Centro de Investigacion en Fisica, Universidad de Sonora, A.P. 5-088, 83190 Hermosillo, Sonora (Mexico)

2000-07-01

Recent research results are presented about the properties of the optical processes of photo transferred thermoluminescence (TLFT), optical whitening (BO), thermoluminescence induced by light (TLL) and its effect in the thermoluminescent curve (Tl) produced by ionizing and non-ionizing radiation. The systematic analysis of all these processes, acquires a singular importance due that actually the alkaline halogenide crystals are object of intense investigations which analyse their potential applications as detectors and radiation dosemeters through stimulated optical luminescence techniques or thermoluminescence. The obtained data show that the Tl curve of material with this nature can be enormously affected by exposure of phosphorus to the environmental light or UV. This is in part due to liberation processes of charge bearers are shouted and makes a subsequent trapping in less temperature traps; at the same time that induce changes in the intensity of determined Tl bands. Additionally, also it is observed that mentioned phenomena are related as with wavelength of incident light as of the illumination time. Finally, the obtained information allows to conclude that although the illumination effect is extremely complex, it is associated and can be explained mainly with phenomena that implicate the electrons excitation trapped in form of F centers and trapping mechanisms or radioactive and non-radioactive recombination. (Author)

Modulation of the thermoluminescence glow curve of sol-gel synthesized SiO2 and Si O-2:Eu through thermal annealing

International Nuclear Information System (INIS)

Salas J, Ch. J.; Cruz V, C.; Bernal, R.; Castano, V. M.

2015-10-01

Full text: Due to the increasing use of ionizing radiations, is necessary to monitor the radiation fields and exposure doses in facilities in which they are used. Different facilities or applications involve the use of different radiation and doses, and the sort of needed dosimetry also varies. Sometimes a conventional thermoluminescence (Tl) dosimetry satisfy the requirements since the record of the accumulated dose in a time interval is enough, but other cases could require for real-time measurement of a radiation field, being required a non-Tl dosimetric technique. On the other hand, different applications involve the use of different dose ranges, and so dosimeters with different sensitivities are needed. To solve the diverse needs of radiation detectors and dosimeters, a lot of phosphors materials has been characterized concerning their dosimetric capabilities. For medical application, biocompatible materials are desirable. In this work, we present experimental evidence that Sol-Gel synthesized SiO 2 and SiO 2 :Eu phosphors exhibit Tl glow curves composed by the superposition of several individual glow peaks each located at different temperature ranging from values below 100 up to temperatures greater than 400 degrees C, whose relative sensitivities can be modified by subjecting the phosphors to different thermal annealing. By modulating the relative intensities of the individual Tl peaks, glow curves with different shapes are obtained in such a way that SiO 2 and SiO 2 :Eu can be used to develop dosimeters useful for different dose ranges, and for both, conventional thermoluminescence dosimetry and non-thermoluminescence afterglow-based) dosimetry. (Author)

Preparation and structural characterization of the thermoluminescent material CaSO4: Dy

International Nuclear Information System (INIS)

Sanchez R, A.; Azorin, J.; Gonzalez M, P.R.; Rivera, T.

2005-01-01

The grade of crystallinity of a material is important so that the one is presented the thermoluminescence phenomenon; for what is necessary to study those structural characteristic of a TL material and to correlate them with its TL response when being irradiated with ionizing radiation. The calcium sulfate activated with Dysprosium (CaSO 4 : Dy) it is a material that has demonstrated its efficiency in the dosimetry of the ionizing radiation for the thermoluminescence method. In this work the structural characterization of this prepared material for the recrystallization method by means of the evaporation of the solvent and their relationship with their TL response is presented. The results showed that the best material to be used in thermoluminescent dosimetry presents a crystalline structure in orthorhombic phase and a particle size in the interval of 80 μm to 200 μm. (Author)

Current status of thermoluminescence studies on minerals and rocks

International Nuclear Information System (INIS)

Sankaran, A.V.; Nambi, K.S.V.; Sunta, C.M.

1982-01-01

The usefulness of thermoluminescence (TL) in geological studies is being increasingly recognized, as may be judged from the considerable volume of literature accumulated over the past couple of decades; besides, a number of seminars, conferences and specialists' meetings have also been held on the subject of applied TL. However, these publications lie scattered over several periodicals and conference proceedings and an interested worker finds it difficult to obtain the gist of the contributions in one place. The present authors felt a need for this and have, therefore, attempted to bring together in this Report the current status of TL research about different minerals; applications in the fields of geochronology, ore-prospecting, stratigraphic correlation, geothermometry and other useful areas are also included. (author)

Dating of aragonite and dolomite from Devil's cave - SP, by dosimetric thermoluminescent method (DTL) and ESR

International Nuclear Information System (INIS)

Tatumi, S.H.

1987-01-01

We have investigated TL (Thermoluminescence) and ESR (electron spin resonance) properties of aragonite and dolomite found at ''Caverna do Diabo (Devil's cave)'' in the state of Sao Paulo to determine the ages of these geological materials. The aragonite, which is not a thermoluminescent material, shows one ESR signal whit g = 2.003. We obtained the age of 1.1 x 10 5 years and the growth rate of 1 μ m/year by the sample calibration with additional Y irradiation. The dolomite gives a TL glow curve with three distinct peaks at 261, 334 and 395 0 C. We found that the fit for the TL glow curve to second-order kinetics can be considerered as very acceptable. Using the second TL peak we obtained the age of 9.4 x 10 5 years and the compatible values of the activation energy (1.90 ± 0,07 eV) by the following methods: Hyperbolic heating, isothermal decay and fractional glow technique. We observed many ESR absorption signals in the dolomite. Three principal signal com g = 2.002, 2.003 and 2.005 were studied. We found that the first and second ESR signals were atributed to the CO 2 - and/or CO 3 3- centers and the last to the CO 3 - centers, and observed that the first ESR signal might related with the second TL peak and the TL sensitivity were associated with the concentration of Mn 2+ [pt

Chemical kinetic modeling of H{sub 2} applications

Energy Technology Data Exchange (ETDEWEB)

Marinov, N.M.; Westbrook, C.K.; Cloutman, L.D. [Lawrence Livermore National Lab., CA (United States)] [and others

1995-09-01

Work being carried out at LLNL has concentrated on studies of the role of chemical kinetics in a variety of problems related to hydrogen combustion in practical combustion systems, with an emphasis on vehicle propulsion. Use of hydrogen offers significant advantages over fossil fuels, and computer modeling provides advantages when used in concert with experimental studies. Many numerical {open_quotes}experiments{close_quotes} can be carried out quickly and efficiently, reducing the cost and time of system development, and many new and speculative concepts can be screened to identify those with sufficient promise to pursue experimentally. This project uses chemical kinetic and fluid dynamic computational modeling to examine the combustion characteristics of systems burning hydrogen, either as the only fuel or mixed with natural gas. Oxidation kinetics are combined with pollutant formation kinetics, including formation of oxides of nitrogen but also including air toxics in natural gas combustion. We have refined many of the elementary kinetic reaction steps in the detailed reaction mechanism for hydrogen oxidation. To extend the model to pressures characteristic of internal combustion engines, it was necessary to apply theoretical pressure falloff formalisms for several key steps in the reaction mechanism. We have continued development of simplified reaction mechanisms for hydrogen oxidation, we have implemented those mechanisms into multidimensional computational fluid dynamics models, and we have used models of chemistry and fluid dynamics to address selected application problems. At the present time, we are using computed high pressure flame, and auto-ignition data to further refine the simplified kinetics models that are then to be used in multidimensional fluid mechanics models. Detailed kinetics studies have investigated hydrogen flames and ignition of hydrogen behind shock waves, intended to refine the detailed reactions mechanisms.

Photoluminescent and Thermoluminescent Studies of Dy3+ and Eu3+ Doped Y2O3 Phosphors.

Science.gov (United States)

Verma, Tarkeshwari; Agrawal, Sadhana

2018-01-01

Eu 3+ doped and Dy 3+ codoped yttrium oxide (Y 2 O 3 ) phosphors have been prepared using solid-state reaction technique (SSR). The prepared phosphors were characterized by X-ray diffractometer (XRD), energy dispersive X-ray (EDX) spectroscopy, scanning electron microscopy (SEM) and Fourier transforms infrared spectroscopy (FTIR) techniques. Photoluminescence (PL) and Thermoluminescence (TL) properties were studied in detail. PL emission spectra were recorded for prepared phosphors under excitation wavelength 254 nm, which show a high intense peak at 613 nm for Y 2 O 3 :Dy 3+ , Eu 3+ (1:1.5 mol %) phosphor. The correlated color temperature (CCT) and CIE analysis have been performed for the synthesized phosphors. TL glow curves were recorded for Eu 3+ doped and Dy 3+ codoped phosphors to study the heating rate effect and dose response. The kinetic parameters were calculated using peak shape method for UV and γ exposures through computerized glow curve deconvolution (CGCD) technique. The phosphors show second order kinetics and activation energies varying from 5.823 × 10 - 1 to 18.608 × 10 - 1  eV.

Quality control of thermoluminesce personal dose monitoring

International Nuclear Information System (INIS)

Shang Aiguo; He Wenchang; Zhao Fengtao

2006-01-01

In order to evaluate the influence factor to thermoluminesce personal dose monitoring result, the every question that can appear based on the fact was analyzed. The results show that the detector, annealing, measuring process can influence the monitoring result. It gives some measures to enhance monitoring quality. (authors)

Thermoluminescence of sulfated zircon exposed to gamma radiation; Termoluminiscencia de circonia sulfatada expuesta a radiacion gamma

Energy Technology Data Exchange (ETDEWEB)

Rubio, E.; Castano, V.M. [Centro de Fisica Aplicada y Tecnologia Avanzada, UNAM, A.P. 1-1010, 76000 Queretaro (Mexico); Mendoza A, E.; Gonzalez, P.R. [ININ, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

2003-07-01

In this work, the thermoluminescent (Tl) signal induced by gamma radiation in zirconia and sulfated zirconia samples embedded in Ptfe pellets is reported and discussed. In this case, samples were obtained through sol-gel method using zirconium n-propoxide and H{sub 2}SO{sub 4} as precursors, and later were subjected to thermal treatment at 600 C to obtain, the tetragonal phase accordingly to X-ray diffraction analysis. Experimental results show that the thermoluminescent glow peak depends on both, the crystalline structure and sulfate concentration. Two maximum peaks were observed located at 147 C and 274 C arising from the electronic transitions. Tl response as a function of the absorbed dose shows a linear increase for a wide of range exposure as well as good stability in time. The high sensitivity, dose linearity and signal stability of this material open the potential possibility to be used for the dosimetry applications. (Author)

Needle-type differential thermoluminescent dosemeter

International Nuclear Information System (INIS)

Kubu, M.

1988-01-01

The dosemeter serves to measure the depth distribution of absorbed dose in a phantom in mixed neutron and gamma radiation fields. It consists of a stratified cylindrical absorber in which alternate moderator and cadmium layers. Inside are two bores along the longitudinal axis for tubes filled with 6 LiF and 7 LiF powder thermoluminescent dosemeters. The device is easily portable and allows to carry out measurements with a high level of reproducibility. (J.B.). 4 figs

An intercomparison of the thermoluminescent efficiency of various preparations of lithium fluoride

CERN Document Server

Driscoll, C M H

1977-01-01

Possible alternative sources of supply of lithium fluoride to that used at present in the NRPB automated TLD system dosemeter are being considered on the grounds of economy and quality control. Initial measurements on the thermoluminescent properties and efficiency of various preparations of lithium fluoride are described, including the Harshaw TLD-700 which is currently in use in the automated thermoluminescent dosemeter. Material obtained from British Nuclear Fuels Ltd (which may be an atypical batch) showed 75% of the sensitivity of the Harshaw material, with around 20% fading of the signal after 1 month's storage. French material, obtained from Desmarquest and Carbonisation Entreprise et Ceramique and used by the Commissariat a l'Energie Atomique, showed good fading resistance but, after standard preparational treatments, was only half as sensitive in the thermoluminescent response. Without additional treatments to improve the characteristics of these materials, they cannot be considered as being satisfac...

Statistical methods to evaluate thermoluminescence ionizing radiation dosimetry data

International Nuclear Information System (INIS)

Segre, Nadia; Matoso, Erika; Fagundes, Rosane Correa

2011-01-01

Ionizing radiation levels, evaluated through the exposure of CaF 2 :Dy thermoluminescence dosimeters (TLD- 200), have been monitored at Centro Experimental Aramar (CEA), located at Ipero in Sao Paulo state, Brazil, since 1991 resulting in a large amount of measurements until 2009 (more than 2,000). The data amount associated with measurements dispersion, since every process has deviation, reinforces the utilization of statistical tools to evaluate the results, procedure also imposed by the Brazilian Standard CNEN-NN-3.01/PR- 3.01-008 which regulates the radiometric environmental monitoring. Thermoluminescence ionizing radiation dosimetry data are statistically compared in order to evaluate potential CEA's activities environmental impact. The statistical tools discussed in this work are box plots, control charts and analysis of variance. (author)

Effect of thermal decomposition of hydroxyapatite on the thermoluminescent response

Energy Technology Data Exchange (ETDEWEB)

Sandoval C, K. J.; Zarate M, J.; Lemus R, J. [Universidad Michoacana de San Nicolas de Hidalgo, Instituto de Investigaciones Metalurgicas, Ciudad Universitaria, Edificio U, 58060 Morelia, Michoacan (Mexico); Rivera M, T., E-mail: karlasandovalc@gmail.com [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Av. Legaria 694, Col. Irrigacion, 11500 Mexico D. F. (Mexico)

2014-08-15

In this work, a study on the thermoluminescence (Tl) induced by gamma radiation in synthetic hydroxyapatite (Hap) annealed at different temperatures obtained by the precipitation method is presented. Synthesis of hydroxyapatite Hap was carried out starting from inorganic precursors [Ca(NO{sub 3}){sub 2}·4H{sub 2}O and (NH{sub 4}){sub 2}HPO{sub 4}]. The precipitate was filtered, washed, dried and then the powder was calcined at different temperatures until the Hap decomposition. The structural and morphological characterization was carried out using both X-ray diffraction (XRD) and scanning electron microscopy (Sem) techniques. Thermoluminescent (Tl) properties of Hap powders were irradiated at different gamma radiation doses. According to X ray diffraction patterns, the tricalcium diphosphate phase (Tcp) appear when the Hap was calcined at 900 grades C. Tl glow curve showed two peaks located at around 200 and 300 grades C, respectively. Tl response as a function of gamma radiation dose was in a wide range from 25 to 100 Gy. The fading of the Tl response at 134 days after irradiation was measured. Experimental results showed that the synthetic hydroxyapatite obtained by precipitation technique may have dosimetric applications when is annealed at temperature of 900 grades C, where the Tcp phase appears and contributes to Tl response, which opens the possibility of using this biomaterials in the area of dosimetry, as they are generally used for biomedical implants. (author)

Thermoluminescence du quartz naturel et artificiel pur ou dopé des ions Fe++ et Fe+++: application à la datation des poteries

Directory of Open Access Journals (Sweden)

1978-01-01

Full Text Available La thermoluminescence constatée sur les échantillons de poteries et conduisant à la datation archéologique de celles-ci, est due aux inclusions de quartz initialement contenues dans l'argile. Nous présentons une étude de la thermoluminescence d'échantillons de quartz monocristallin synthétique dans lesquels des impuretés ont été volontairement ajoutées et appliquons les résultats à une nouvelle technique de datation, la méthode DATE (différence d'atténuation temporelle des émissions. La termoluminiscencia constatada en muestras de cerámica permite una datación arqueológica es debida a las inclusiones de cuarzo inicialmente contenidas en la arcilla. Se presenta un estudio de la termoluminiscencia de muestras de cuarzo monocristalino sintético en las cuales han sido colocadas voluntariamente impurezas se han aplicado los resultados de una nueva técnica de fechado, el método DATE (Diferencia de atenuación temporal de emisiones. The thermoluminescence observed on samples of pottery and leading to their archaeological dating is a result of the presence of quartz particles originally enclosed in the clay. We offer a study of the termoluminescence of samples of synthetic mono-crystalline quartz doped in with impurities and apply the results to a new dating technique, the 'DATE' method, based upon difference in time attenuation of the emissions.

Thermoluminescent response of dosemeters TLD-100 exposed to distinct baker protocols, irradiation and reading

International Nuclear Information System (INIS)

Estrada E, D.

2002-01-01

that for dosemeters of 0.89 x 3.17 x 3.17 mm 3 of TLD-100. Given the importance of having values of relative thermoluminescent efficiency reliable in applications associated to medical dosimetry, the main conclusion of this work is the recommendation of measuring relative efficiencies following a protocol of careful work and previously defined so much for the charged particle radiation as for the gamma radiation and controlling all the experimental factors involved. (Author)

Thermoluminescent response of LaAlO{sub 3}:Pr; Respuesta termoluminiscente de LaAlO{sub 3}:Pr

Energy Technology Data Exchange (ETDEWEB)

Morales H, A.; Zarate M, J. [Universidad Michoacana de San Nicolas de Hidalgo, Instituto de Investigacion en Metalurgia y Materiales, Ciudad Universitaria, Edif. U, 58060 Morelia, Michoacan (Mexico); Azorin N, J. [Universidad Autonoma Metropolitana, Unidad Iztapalapa, Av. San Rafael Atlixco 186, Col. Vicentina, 09340 Mexico D. F. (Mexico); Rivera M, T., E-mail: feyo_yo@hotmail.com [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Av. Legaria 694, 11500 Mexico D. F. (Mexico)

2015-10-15

In this study, the thermoluminescence response of doped lanthanum aluminate (LaAlO{sub 3}) with praseodymium ion (Pr) obtained by the Pechini method and drying by the spraying technique Spry Dryer was studied. The obtained powders were analyzed structurally by the X-ray diffraction technique; the morphological characterization was by the scanning electron microscopy technique. The obtained powders at 800 degrees C presented crystallinity and showed a Rhombohedral crystal structure, this phase was observed by X-ray diffraction patterns. Thermoluminescence response of LaAlO{sub 3}:Pr showed a brightness curve with a peak centered at 157 degrees C. The sensitivity of the doped samples was improved about 90 times in comparison with the undoped sample. Thermoluminescence response in function of the wavelength showed a maximum at 230 nm, reproducibility of thermoluminescence response was ±50%. Also the fading in thermoluminescence response was studied. (Author)

Modulation of the thermoluminescence glow curve of sol-gel synthesized SiO{sub 2} and Si O-2:Eu through thermal annealing

Energy Technology Data Exchange (ETDEWEB)

Salas J, Ch. J.; Cruz V, C. [Universidad de Sonora, Departamento de Investigacion en Polimeros y Materiales, Apdo. Postal 130, 83000 Hermosillo, Sonora (Mexico); Bernal, R. [Universidad de Sonora, Departamento de Investigacion en Fisica, Apdo. Postal 5-088, 83190 Hermosillo, Sonora (Mexico); Castano, V. M., E-mail: salasjuarez@gimmunison.com [UNAM, Centro de Fisica Aplicada y Tecnologia Avanzada, Apdo. Postal 1-1010, 76000 Queretaro, Qro. (Mexico)

2015-10-15

Full text: Due to the increasing use of ionizing radiations, is necessary to monitor the radiation fields and exposure doses in facilities in which they are used. Different facilities or applications involve the use of different radiation and doses, and the sort of needed dosimetry also varies. Sometimes a conventional thermoluminescence (Tl) dosimetry satisfy the requirements since the record of the accumulated dose in a time interval is enough, but other cases could require for real-time measurement of a radiation field, being required a non-Tl dosimetric technique. On the other hand, different applications involve the use of different dose ranges, and so dosimeters with different sensitivities are needed. To solve the diverse needs of radiation detectors and dosimeters, a lot of phosphors materials has been characterized concerning their dosimetric capabilities. For medical application, biocompatible materials are desirable. In this work, we present experimental evidence that Sol-Gel synthesized SiO{sub 2} and SiO{sub 2}:Eu phosphors exhibit Tl glow curves composed by the superposition of several individual glow peaks each located at different temperature ranging from values below 100 up to temperatures greater than 400 degrees C, whose relative sensitivities can be modified by subjecting the phosphors to different thermal annealing. By modulating the relative intensities of the individual Tl peaks, glow curves with different shapes are obtained in such a way that SiO{sub 2} and SiO{sub 2}:Eu can be used to develop dosimeters useful for different dose ranges, and for both, conventional thermoluminescence dosimetry and non-thermoluminescence afterglow-based) dosimetry. (Author)

Method of preparing a thermoluminescent phosphor

Science.gov (United States)

Lasky, Jerome B.; Moran, Paul R.

1979-01-01

A thermoluminescent phosphor comprising LiF doped with boron and magnesium is produced by diffusion of boron into a conventional LiF phosphor doped with magnesium. Where the boron dopant is made to penetrate only the outer layer of the phosphor, it can be used to detect shallowly penetrating radiation such as tritium beta ays in the presence of a background of more penetrating radiation.

Study of natural thermoluminescence of quartzite in a gold and uranium mineralized zone (Canavieiras, Jacobina, Brazil)

International Nuclear Information System (INIS)

Ferreira, J.; Nordemann, D.

1976-01-01

The quartzite of the Canavieiras gold mine (Jacobina, Bahia, Brazil) exhibits a high temperature peak (280 +- 2) 0 C in its natural thermoluminescence glow curve. It was experimentally determined that the amount of light in this peak could be reproduced to within 5% for grain sizes between 80 and 100 mesh (0.149 and 0.177 mm). A positive correlation was found between the amount of this thermoluminescence and the uranium content with saturation beginning to be detected at the maximum (700 ppm) amount of uranium found. Assuming that the thermoluminescence peak used is at a temperature high enough to permit accumulation and stability at room temperatures, the thermoluminescence found could have accumulated in (12.1 +- 0.3) x 10 6 years. This may date a complete liberation of trapped electrons in conjunction with a well documented initiation of weathering. (author) [pt

Analysis of the deconvolution of the thermoluminescent curve of the zirconium oxide doped with graphite

International Nuclear Information System (INIS)

Salas C, P.; Estrada G, R.; Gonzalez M, P.R.; Mendoza A, D.

2003-01-01

In this work, we present a mathematical analysis of the behavior of the thermoluminescent curve (Tl) induced by gamma radiation in samples made of zirconium oxide doped with different amounts of graphite. In accordance with the results gamma radiation induces a Tl curve with two maximum of emission localized in the temperatures at 139 and 250 C, the area under the curve is increasing as a function of the time of exposition to the radiation. The analysis of curve deconvolution, in accordance with the theory which indicates that this behavior must be obey a Boltzmann distribution, we found that each one of them has a different growth velocity as the time of exposition increase. In the same way, we observed that after the irradiation was suspended each one of the maximum decrease with different velocity. The behaviour observed in the samples is very interesting because the zirconium oxide has attracted the interest of many research groups, this material has demonstrated to have many applications in thermoluminescent dosimetry and it can be used in the quantification of radiation. (Author)

Study of radioactive sources accumulation with application of thermoluminescence dosemeters on the base of alkaline earth metals sulfates

International Nuclear Information System (INIS)

Tokbergenov, I.; Sadykov, T.

2001-01-01

Methodic for study of accumulation and distribution of radioactive sources in a nature objects is developed. An essence of the method consists of in that quantity of accumulated radioactive sources in a nature objects is defining by absorption dose measured with help of thermoluminescent dosemeters on the base of alkaline earth metals sulfates such as CaSO 4 :Dy and SrSO 4 :Eu

Thermoluminescence sensitivity of ulexite after UV irradiation

Energy Technology Data Exchange (ETDEWEB)

Topaksu, M., E-mail: mats@cu.edu.tr [Cukurova University, Arts-Sciences Faculty, Physics Department, 01330 Adana (Turkey); CIEMAT, Av. Complutense 22, 28040 Madrid (Spain); Correcher, V. [CIEMAT, Av. Complutense 22, 28040 Madrid (Spain); Garcia-Guinea, J. [Museo Nacional de Ciencias Naturales, (CSIC), C/José Gutiérrez Abascal 2, 28006 Madrid (Spain)

2015-04-15

Highlights: •UV-induced thermoluminescence emission of Turkish ulexite was studied. •There are three groups of components. •The UV exposures were performed at controlled temperatures. -- Abstract: The effects of UV radiation on the thermoluminescence (TL) properties of natural materials, in contrast to synthetic materials, have been scarcely studied. We report on the UV-induced thermoluminescence emission of a Turkish ulexite (NaCaB{sub 5}O{sub 6}(OH){sub 6}·5H{sub 2}O) that displays very complex TL glow curves, with at least three groups of components peaked at 130–140 °C, 240 °C and, 340 °C, wherein the last group is weaker. Such emission could be associated with structural changes in the lattice as well as alkali self-diffusion processes. The UV exposure performed at controlled temperatures (at room temperature (RT), 50 °C and 100 °C) produced a (i) different evolutions of the intensities of each maximum, which are directly related to the controlled thermal treatment; (ii) different intensity ratios among the groups of components; (iii) different activation energies (E{sub a}) (1.13 eV for RT, 0.99 eV for 50 °C and 0.49 eV for 100 °C) calculated using the initial rise method; and (iv) similar scattering values (12.4%, 8.2% and 12.8%), which were not a function of the controlled temperature. The thermal stability tests conducted on this borate at different temperatures, based on the T{sub stop} protocol, confirm the presence of a continuum in the distribution of the trap system with progressively increasing E{sub a} (from 0.60 to 0.90 eV)

Thermoluminescence characterization of LiMgF3: DyF3 phosphors exposed to beta radiation

International Nuclear Information System (INIS)

Bernal, R.; Alday S, K.R.; Brown, F.; Cruz V, C.; Furetta, C.; Cruz Z, E.; Kitis, G.

2006-01-01

LiMgF 3 : DyF 3 phosphors were obtained as polycrystalline solids from the melting of component salts, with two DyF 3 concentrations, 2.02 % mol, and 4.04 % mol. In order to guarantee the homogeneity of composition, the samples were crushed and the resulting powder was pressed to form pellet-shaped phosphors, some of which were sintered at 700 C for 5 h under air atmosphere. Thermoluminescence measurements of beta irradiated samples show that these phosphors exhibit adequate properties to be considered for development of thermoluminescence dosimeters. Integrated thermoluminescence as a function of dose displays a linear dependence with dose for doses below 20.0 Gy. (Author)

Thermoluminescence authentication of T'ang and Han Dynasty pottery

International Nuclear Information System (INIS)

Price, D.M.

1997-01-01

More than 80 pieces of T'ang Dynasty and 40 Han Dynasty style ceramic wares have been analysed to determine the amount of thermoluminescence (TL) accumulated since the initial firing of the object and the level of the radiation flux which has created the TL. This paper presents a summary of the thermoluminescence analysis results. Approximately 60% of Han ceramics and 45% of the T'ang pottery authenticated have been shown to belong to periods other than that stylistically suggested. Items which have been found not to be of the anticipated antiquity generally fall into distinct age groups. Of the T'ang wares the most commonly copied item is found to be the horse and for the Han pieces, human figures and ewers/pots/vases represent the most frequently reproduced wares

The thermoluminescence of carp otoliths: A fingerprint in ...

African Journals Online (AJOL)

use

2011-12-14

Dec 14, 2011 ... provide a quick and qualitative means for environmental assessments in lake pollution. Key words: Thermoluminescence, fish otolith, heavy-metal elements, lake, pollution. INTRODUCTION. Fish otoliths are widely .... cleaned HDPE plastic bottles that have been rinsed with sample three times prior to use.

The thermoluminescence glow-curve analysis using GlowFit - the new powerful tool for deconvolution

International Nuclear Information System (INIS)

Puchalska, M.; Bilski, P.

2005-10-01

A new computer program, GlowFit, for deconvoluting first-order kinetics thermoluminescence (TL) glow-curves has been developed. A non-linear function describing a single glow-peak is fitted to experimental points using the least squares Levenberg-Marquardt method. The main advantage of GlowFit is in its ability to resolve complex TL glow-curves consisting of strongly overlapping peaks, such as those observed in heavily doped LiF:Mg,Ti (MTT) detectors. This resolution is achieved mainly by setting constraints or by fixing selected parameters. The initial values of the fitted parameters are placed in the so-called pattern files. GlowFit is a Microsoft Windows-operated user-friendly program. Its graphic interface enables easy intuitive manipulation of glow-peaks, at the initial stage (parameter initialization) and at the final stage (manual adjustment) of fitting peak parameters to the glow-curves. The program is freely downloadable from the web site www.ifj.edu.pl/NPP/deconvolution.htm (author)

Thermoluminescence of novel zinc oxide nano phosphors obtained by glycine-based solution combustion synthesis

Energy Technology Data Exchange (ETDEWEB)

Orante B, V. R.; Escobar O, F. M.; Cruz V, C. [Universidad de Sonora, Departamento de Investigacion en Polimeros y Materiales, Apdo. Postal 130, 83000 Hermosillo, Sonora (Mexico); Bernal, R., E-mail: victor.orante@polimeros.uson.mx [Universidad de Sonora, Departamento de Investigacion en Fisica, Apdo. Postal 5-088, 83190 Hermosillo, Sonora (Mexico)

2015-10-15

Full text: High-dose thermoluminescence dosimetry properties of novel zinc oxide nano phosphors synthesized by a solution combustion method in a glycine-nitrate process are presented for the very first time in this work. Sintered particles with sizes ranging between ∼500 nm and ∼2 μm were obtained by annealing the synthesized Zn O at 900 degrees C during 2 h in air. X-ray diffraction patterns indicate the presence of the Zn O hexagonal phase, without any remaining nitrate peaks observed. Thermoluminescence glow curves of Zn O obtained after being exposed to beta radiation consists of two maxima: one located at ∼ 149 degrees C and another at ∼ 308 degrees C, the latter being the dosimetric component of the curve. The integrated Tl fading displays an asymptotic behaviour for times longer than 16 h between irradiation and the corresponding Tl readout, as well as a linear behaviour of the dose response without saturation in the studied dose interval (from 12.5 up to 400 Gy). Such features place synthesized Zn O as a promising material for high-dose radiation dosimetry applications. (Author)

Thermoluminescence of novel zinc oxide nano phosphors obtained by glycine-based solution combustion synthesis

International Nuclear Information System (INIS)

Orante B, V. R.; Escobar O, F. M.; Cruz V, C.; Bernal, R.

2015-10-01

Full text: High-dose thermoluminescence dosimetry properties of novel zinc oxide nano phosphors synthesized by a solution combustion method in a glycine-nitrate process are presented for the very first time in this work. Sintered particles with sizes ranging between ∼500 nm and ∼2 μm were obtained by annealing the synthesized Zn O at 900 degrees C during 2 h in air. X-ray diffraction patterns indicate the presence of the Zn O hexagonal phase, without any remaining nitrate peaks observed. Thermoluminescence glow curves of Zn O obtained after being exposed to beta radiation consists of two maxima: one located at ∼ 149 degrees C and another at ∼ 308 degrees C, the latter being the dosimetric component of the curve. The integrated Tl fading displays an asymptotic behaviour for times longer than 16 h between irradiation and the corresponding Tl readout, as well as a linear behaviour of the dose response without saturation in the studied dose interval (from 12.5 up to 400 Gy). Such features place synthesized Zn O as a promising material for high-dose radiation dosimetry applications. (Author)

Synthesis and thermoluminescence of LaAlO3:Pr3+ to UVC radiation dosimetry

International Nuclear Information System (INIS)

Morales-Hernández, A.; Zarate-Medina, J.; Contreras-García, M.E.; Azorín-Nieto, J.; Rivera-Montalvo, T.

2016-01-01

Thermoluminescent (TL) response of trivalent praseodymium ion doped lanthanum aluminate (LaAlO 3 :Pr 3+ ) obtained by Pechini method and Spray Dryer was studied. TL response of LaAlO 3 :Pr 3+ powders submitted at 1600 °C exhibited one peak centered at 157 °C. Sensitivity of LaAlO 3 :Pr 3+ was improved in around 90 times compared with undoped LaAlO 3 . TL response as a function of wavelength showed a maximum in 230 nm. Dosimetric characteristics of LaAlO 3 :Pr 3+ under UVR radiation effects were analyzed. Evaluation of activation energy was obtained by Glow Fit v.1.3 software. Experimental results about thermoluminescent characteristics of LaAlO 3 :Pr 3+ suggest as good candidate to be employed as a complementary thermoluminescent device with other TL phosphors as aluminum oxide - Highlights: • High sensitivity of new phosphor to UVC dosimetry was is studied. • Thermoluminescence response of LaAlO 3 :Pr 3+ is presented. • LaAlO 3 :Pr 3+ is suggested as UVCR dosimeter. • TL response of LaAlO 3 :Pr 3+ has dependence on sintering temperature.

Statistics of fermions in the Randall-Wilkins model for kinetics of general order

International Nuclear Information System (INIS)

Nieto H, B.; Azorin N, J.; Vazquez C, G.A.

2004-01-01

As a theoretical planning of the thermoluminescence phenomena (Tl), we study the behavior of the systems formed by fermions, which are related with this phenomenon establishing a generalization of the Randall-Wilkins model, as for first order kinetics as for general order (equation of May and Partridge) in which we consider a of Fermi-Dirac statistics. As consequence of this study a new variable is manifested: the chemical potential, also we establish its relationship with some of the other magnitudes already known in Tl. (Author)

Synthesis of CaF2: dy for thermoluminescent dosimetry

International Nuclear Information System (INIS)

Yamato, M.E.P.; Vasconcelos, D.A.A. de; Asfora, V.K.; Khoury, H.J.; Santos, R.A.; Barros, V.S.M.

2015-01-01

Calcium Fluoride doped with dysprosium is a known thermoluminescent material for applications that require highly sensitive dosimeters. Research in novel methods such as Combustion Synthesis (CS) has been ongoing for several years at the University of Pernambuco. The method uses the heat of the oxi-redox reaction a between nitrate and a fuel. This work presents results of CaF 2 :Dy produced by combustion synthesis under different fabrication conditions. Samples were prepared by mixing stoichiometric amounts of calcium nitrate, urea and ammonium nitrate in a beaker under vigorous stirring. The resulting gel was transferred to a pre-heated muffle furnace were the combustion reaction occurred after a few minutes. For comparison, a variation of the production method with the same amounts of nitrate, ammonium fluoride and dopant, but without using the fuel was prepared. For both methods the resulting powder was pelleted and irradiated with Co-60 gamma radiation. The reproducibility and sensitivity for gamma dose irradiation was tested and results showed that optimum TL sample reproducibility was without the urea as fuel. Samples were then prepared with 0.05, 0.10, 0.15 and 0.20 mol% Dy concentration. The highest TL sensitivity was found for samples with 0.15 mol% Dy and sintered at 400 deg C for 3.5 h in air. The TL emission spectra, obtained using a Hammamatsu optical spectrometer, was comparable with commercial CaF 2 :Dy. Thermoluminescence was measured in a Harshaw-Bicron 3500 TL Reader. The glow curve showed stable dosimetric peaks at around 200, 235 and 300 deg C were a linear dose response curve was obtained for the range 100 mGy to 1000 mGy. (author)

Thermoluminescence of pyramid stones

International Nuclear Information System (INIS)

Gomaa, M.A.; Eid, A.M.

1982-01-01

It is the aim of the present study to investigate some thermoluminescence properties of pyramid stones. Using a few grammes of pyramid stones from Pyramids I and II, the TL glow peaks were observed at 250 and 310 0 C, respectively. The TL glow peaks of samples annealed at 600 0 C, then exposed to 60 Co γ-rays were observed at 120, 190 and 310 0 C, respectively. The accumulated dose of natural samples is estimated to be around 310 Gray (31 krad). By assuming an annual dose is 1 mGy, the estimated age of pyramid stones is 0.31 M year. (author)

Thermoluminescence of pyramid stones

Energy Technology Data Exchange (ETDEWEB)

Gomaa, M A; Eid, A M [Atomic Energy Establishment, Cairo (Egypt)

1982-01-01

It is the aim of the present study to investigate some thermoluminescence properties of pyramid stones. Using a few grammes of pyramid stones from Pyramids I and II, the TL glow peaks were observed at 250 and 310/sup 0/C, respectively. The TL glow peaks of samples annealed at 600/sup 0/C, then exposed to /sup 60/Co ..gamma..-rays were observed at 120, 190 and 310/sup 0/C, respectively. The accumulated dose of natural samples is estimated to be around 310 Gray (31 krad). By assuming an annual dose is 1 mGy, the estimated age of pyramid stones is 0.31 M year.

Application of thermoluminescence dating on pressed crystalline samples to determine the geological age at some areas in Eastern South, Vietnam

International Nuclear Information System (INIS)

Do Duy Khiem; Luu Anh Tuyen; Phan Trong Phuc; Nguyen Thi Ngoc Hue; Pham Thi Hue; La Ly Nguyen; Ha Quang Hai

2016-01-01

The terrestrial part of eastern margin of the Mekong Basin is formed by outcrop of the pre-Holocen Cenozoic sequence. Almost previous studies concerned in using relative methods in geologic dating at the Mekong Basin, therefore, the ages of its stratigraphy are still unclear. The thermoluminescence (TL) dating was considered as one of the precise methods in geologic dating. In our study, we used TL dating for some areas at Eastern South, Vietnam including Ba Mieu Formation and the Thu Duc Formation at some areas in Dong Nai province and Ho Chi Minh City. This work has been the first application of TL for in geologic dating by a domestic laboratory. Experimental measurements of TL were performed using pressed crystalline quartz specimens from sediment samples. The results show that the Ba Mieu Formation was deposited about 238±22 ka and the Thu Duc Formation was deposited about 199±21 ka. (author)

UV light-induced thermoluminescence of Er + Li doped ZrO2

International Nuclear Information System (INIS)

Hristov, H; Arhangelova, N; Velev, V; Penev, I; Bello, M; Moschini, G; Uzunov, N

2010-01-01

Analysis of the thermoluminescence (TL) properties of ZrO 2 doped with Eu and Li has been conducted. Different quantities of lithium co-dopant have been added as Li 2 CO 3 to a mixture of ZrO 2 with 1wt% Er. Pellets sintered at a temperature of 1200 0 C have been prepared and the kinetic parameters of the phosphors have been studied after irradiation with UV light. It has been shown that the addition of 8 to 10 wt% of Li to the mixture of ZrO 2 with 1wt% Er yields a maximum intensity of the peaks at 65 0 C and at 105 0 C. Spectral emission and spectral sensitivity of the phosphors have been studied. The analysis applied to TL glow curves, obtained from the UV irradiated phosphors and kept after the irradiation at different times in a dark storage, revealed that the peaks at 65 0 C and 105 0 C have relatively long fading. It is concluded that the phosphors thus obtained possess a good sensitivity to the UV emission and could be appropriate phosphors for detection and quantitative measurements of UV light.

N.R.P.B.'s new record-keeping service and thermoluminescent dosemeter

International Nuclear Information System (INIS)

Dennis, J.A.; Marshall, T.O.; Shaw, K.B.; Kendall, G.M.

1977-01-01

With the approval of the Health and Safety Executive the National Radiological Protection Board is introducing a radiation dose record keeping service in association with a thermoluminescent dosimeter. This service will relieve employers of the responsibility for maintaining and keeping dose records. Both the record keeping and dosimeter systems are described, including the documents which will be produced for employers. The thermoluminescent dosimeter is more accurate and less sensitive to environmental factors than the film dosimeter, which it replaces. It also reduces the consumption of materials and, with automated processing, is labour saving. (author)

Radiation effects in the polycarbonate of bisphenol-A. Thermoluminescence electron spin resonance and charged particle track studies

International Nuclear Information System (INIS)

Edmonds, E.A.

1978-09-01

A detailed investigation is presented of the thermoluminescence observable above room temperature from the polycarbonate of bisphenol-A after its exposure to different radiations. A correlation study is described by which features of the complex thermoluminescence glow curve from a commercial grade of the polycarbonate of bisphenol-A are related to the etchability of charged particle damage trails and the radiogenic ESR signal. A model is presented whereby the etchability of charged particle damage trails is associated with chain scission caused by the high local dose of radiation in the vicinity of the trajectories of charged particles. Methods by which activation constants controlling the thermoluminescence glow curve can be evaluated are discussed and results are presented. It is concluded that glow peaks associated with the ESR signal or enhanced etchability are related to small-scale motions in the molecular matrix of the polycarbonate of bisphenol-A. These motions are thermally activated in accord with the simple Boltzmann relation usually incorporated into theories of thermoluminescence. Another component glow peak of the thermoluminescence glow curve is shown to be associated with the glass-rubber transition in the polycarbonate of bisphenol-A. Different features of the thermoluminescence glow curve can be related to relaxations of the polymer matrix and decomposition of the matrix. It is confirmed that the dominant bulk effect of radiation in the polycarbonate of bisphenol-A exposed to large doses of radiation is chain scission. (author)

Retrospective dosimetry assessment using the 380 deg. C thermoluminescence peak of tooth enamel

Energy Technology Data Exchange (ETDEWEB)

Secu, C.E. [National Institute for Materials Physics, PO Box MG-7, 77125 Bucharest-Magurele (Romania); Cherestes, M. [Dozimed Ltd., Dosimetry Laboratory, 77125 Bucharest-Magurele (Romania); Secu, M., E-mail: msecu@infim.ro [National Institute for Materials Physics, PO Box MG-7, 77125 Bucharest-Magurele (Romania); Cherestes, C.; Paraschiva, V. [Dozimed Ltd., Dosimetry Laboratory, 77125 Bucharest-Magurele (Romania); Barca, C. [Faculty of Physics, University of Bucharest, 77125 Bucharest-Magurele (Romania)

2011-10-15

The thermoluminescence (TL) response to gamma-ray irradiation of tooth enamel is reported. The tooth enamel was separated from dentine by using mechanical and physico-chemical procedures followed by grinding (grain size {approx}100 {mu}m) and etching. The TL was attributed to the recombination of CO{sub 2}{sup -} radicals incorporated into or attached to the surface of hydroxyapatite crystals. The growth of the {approx}380 deg. C TL peak with absorbed dose was examined with irradiated tooth enamel samples and reconstructed doses evaluated for tooth enamel samples from four human subjects. - Highlights: > Thermoluminescence response after gamma-ray irradiation of tooth enamel was investigated. > Thermoluminescence was attributed to the recombination of CO{sub 2}{sup -} radicals. > CO{sub 2}{sup -} radicals are produced inside or at the surface of hydroxyapatite crystals. > From the growth of the 380C peak reconstructed doses have been evaluated.

Thermoluminescence in alkali halides irradiated at 80K; Termoluminiscencia en haluros alcalinos irradiados a 80K

Energy Technology Data Exchange (ETDEWEB)

Jimenez de Castro, M

1978-07-01

The thermoluminescence, the thermally stimulated currents and the thermal stability of the F centres induced in pure NaCl and KC1 crystals by X irradiation at 80K have been studied in detail, In the range between 80 and 300K. The thermoluminescent processes induced by illumination at 80K with F light in samples previously irradiated at room temperature has also been studied. It has been clearly observed the existence of thermoluminescent processes due to electrons and holes thermally released from traps, in which the F centres are not involved. The existence of hole-F centre recombination has not been observed. There are several thermoluminescent processes in both materials which are scribed to the recombination of F centres with mobile interstitial halogen atoms thermally released from traps, which are likely monovalent impurities in this temperature interval. The light emitting stage in these processes is originated by the formation of self trapped excitons. (Author) 66 refs.

The applications of chemical thermodynamics and chemical kinetics to planetary atmospheres research

Science.gov (United States)

Fegley, Bruce, Jr.

1990-01-01

A review of the applications of chemical thermodynamics and chemical kinetics to planetary atmospheres research during the past four decades is presented with an emphasis on chemical equilibrium models and thermochemical kinetics. Several current problems in planetary atmospheres research such as the origin of the atmospheres of the terrestrial planets, atmosphere-surface interactions on Venus and Mars, deep mixing in the atmospheres of the gas giant planets, and the origin of the atmospheres of outer planet satellites all require laboratory data on the kinetics of thermochemical reactions for their solution.

Continuum-Kinetic Models and Numerical Methods for Multiphase Applications

Science.gov (United States)

Nault, Isaac Michael

This thesis presents a continuum-kinetic approach for modeling general problems in multiphase solid mechanics. In this context, a continuum model refers to any model, typically on the macro-scale, in which continuous state variables are used to capture the most important physics: conservation of mass, momentum, and energy. A kinetic model refers to any model, typically on the meso-scale, which captures the statistical motion and evolution of microscopic entitites. Multiphase phenomena usually involve non-negligible micro or meso-scopic effects at the interfaces between phases. The approach developed in the thesis attempts to combine the computational performance benefits of a continuum model with the physical accuracy of a kinetic model when applied to a multiphase problem. The approach is applied to modeling a single particle impact in Cold Spray, an engineering process that intimately involves the interaction of crystal grains with high-magnitude elastic waves. Such a situation could be classified a multiphase application due to the discrete nature of grains on the spatial scale of the problem. For this application, a hyper elasto-plastic model is solved by a finite volume method with approximate Riemann solver. The results of this model are compared for two types of plastic closure: a phenomenological macro-scale constitutive law, and a physics-based meso-scale Crystal Plasticity model.

Thermoluminescence and cathodoluminescence studies of calcite and MgO: surface defects and heat treatment

International Nuclear Information System (INIS)

Goeksu, H.Y.; Brown, L.M.

1988-01-01

Some of the problems which preclude accurate thermoluminescence (TL) dating of geologically formed calcite stem from different sample pre-treatment procedures, such as grinding, drilling or pre-heating. It has long been known that grinding can introduce spurious TL in calcite, but there have been wide differences of opinion as to the magnitude of the influence and its importance. Therefore, various grinding and acid-washing procedures have been suggested to avoid spurious thermoluminescence. Various models have been developed to explain the mechanism. We have studied the changes in thermoluminescence (TL) and cathodoluminescence (CL) properties as well as in the spectral composition of the glow from calcite and MgO due to surface defects and heat treatment. It is found that both laboratory heat treatment and surface indents give rise to changes in TL efficiency. (author)

Neutron spatial distribution measurement with 6Li-contained thermoluminescent sheets

International Nuclear Information System (INIS)

Konnai, A.; Odano, N.; Sawamura, H.; Ozasa, N.; Ishikawa, Y.

2006-01-01

We have been developing a thermoluminescent (TL) sheet for photon dosimetry (TL sheet) with thermoluminescent material of LiF:Mg, Cu, P and a co-polymer of ethylene and tetrafluoroethylene. For the purpose of a development of simple method for neutron spatial distribution measurement, TL sheet for neutron detection (NTL sheet) is made by adding 94.7% enriched 6 LiF to TL sheet. TL material in TL sheet is directly excited by ionizing radiation whereas, in the case of neutron detection, TL material in NTL sheet is indirectly excited by neutron capture reaction. That is neutron distribution can be obtained with TL caused by α particle from 6 Li(n, α) 3 H reaction. Responses of NTL sheets to neutrons were examined at the neutron beam irradiation facility for Boron Neutron Capture Therapy (BNCT) in JRR-4 research reactor in Japan Atomic Energy Agency. TL and NTL sheets were exposed to striped and roundly distributed neutron fields. Attenuations of neutron flux in air and water were also observed using NTL sheets. TL sheets were also exposed on the same conditions and compared with NTL sheets. TL intensity ratios of NTL sheet to TL sheet were consistent with the calculated value from 6 Li content. Thermal neutron attenuation observed by NTL sheet also corresponded with the result measured by Au wire radioactivation and TLD chips, which were currently used in BNCT at JRR-4. These results were analyzed with by Monte Carlo simulation. The present results indicated that NTL sheet is applicable to measurement of neutron spatial distribution. (author)

Comparison of responses of thermoluminescent dosemeters irradiated by soft x-rays at very low and very high dose rate levels

International Nuclear Information System (INIS)

Pietrikova-Farnikova, M.; Krasa, J.; Juha, L.

1994-01-01

Recent great progress in construction and application of bright sources of soft X-rays gave a strong impetus for the development of methods of their dosimetric diagnostics. The soft X-ray sources are primarily represented by synchrotron radiation sources and by sources based on laser-produced plasma, including X-ray lasers. Their characteristics spread over a very wide region of photon energies, peak and average powers and densities. From our preliminary experiments it follows that thermoluminescent dosemeters can serve as a suitable tool for the determination of these characteristics. Problem lies in the fact that routine use of the thermoluminescent dosemeters for the dosimetry of soft X-rays requires their spectral calibration, which can be carried out with low peak power sources (synchrotron radiation and radionuclide sources). On the contrary, many important sources, especially these based on laser-produced plasmas, exhibit a very high peak power, i.e. dosemeters are irradiated at extremely high dose rate. In comparative experiments carried out with laser-produced plasmas and radionuclides using TLD 200 (CaF 2 :Dy) and GR 200A (LiF:Mg,Cu,P) it was satisfactorily proven that total thermoluminescent signals are independent of the dose rate. Dependence of glow curve shapes on the dose, dose rate and photon energy were equally determined

Thermoluminescence dating of pleistocene sediments

International Nuclear Information System (INIS)

Poupeau, G.; Souza, J.H.

1984-01-01

After a short introduction on recent trends in quaternary geochronology, this article focuses on the thermoluminescence (TL) dating of sediments, whose principles, present limits and prospects are discussed. Results are presented for TL behavior of sands from various geological contexts in Brazil. They show that the coarse (approx. 100-200 μm) quartz fraction of coastal and intracontinental, eolian and fluvial - type deposits, might be datable by TL from the upper Holocene to at least the base of the upper Pleistocene, with a precision of +- 10-15%. (Author) [pt

Thermoluminescence dating of pleistocene sediments

International Nuclear Information System (INIS)

Poupeau, G.; Souza, J.H.; Rivera, A.

1984-01-01

After a short introduction on recent trends in quaternary geochronology, this article focuses on the thermoluminescence dating of sediments, whose principles and present limits and prospects are discussed. Results are presented for the TL behaviour of sands from various geological contexts in Brazil. They show that the coarse (approx. 100-200μm) quartz fraction of coastal and intra continental, eolian and fluvial-type deposits, might be datable by TL from the upper Holocene to at least the basis of the upper Pleistocene, with a precision of + - 10-15%. (Author) [pt

Natural dose level determination at Johor State with thermoluminescence dosimetry

International Nuclear Information System (INIS)

Ahmad Termizi Ramli; Yusof Jasman

1995-01-01

This paperwork presented the results of using thermoluminescence dosimetry (TLD) method in measuring background dose level, which is done at State of Johor, South Malaysia. The problems faced also discussed

Storage Telemetry of Radionuclide Tracers by Implantable Thermoluminescent Dosimeters

DEFF Research Database (Denmark)

Bojsen, J.; Møller, U.; Christensen, Poul

1977-01-01

A storage telemetrical method using thermoluminescent (TL) dosimeters for long-term measurements of incorporated radioactive substances in unrestrained rats has been developed. The system has been used in combination with radiotelemetrical registration of the circadian temperature rhythm. By sequ...

Carbon doped lanthanum aluminate (LaAlO3:C) synthesized by solid state reaction for application in UV thermoluminescent dosimetry

International Nuclear Information System (INIS)

Alves, N.

2015-01-01

In this work we discuss the TL output for LaAlO 3 :C crystals grown by using three different combinations of Al 2 O 3 , La 2 O 3 and carbon atoms during the synthesis process. Recently, LaAlO 3 single crystals, co-doped with Ce 3+ and Dy 3+ rare earth trivalent ions and grown under hydrothermal conditions, have been reported to show high thermoluminescent response (TL) when exposed to low levels of ultraviolet radiation (UVR). However, undoped LaAlO 3 synthesized by solid state reaction method from the 1:1 mixture of aluminum and lanthanum oxide under reducing atmosphere revealed to have still higher thermoluminescent sensitivity to UV photon fields than the co-doped with Ce 3+ and Dy 3+ . It is well known that carbon doped aluminum oxide monocrystals have excellent TL and photoluminescent response properties for X-rays, UV and gamma radiation fields. Thus, we conducted three different syntheses of LaAlO 3 by this solid state reaction method, doping the mixture with carbon. The lanthanum aluminate polycrystals were synthesized from the 1:1 mixture of aluminum and lanthanum oxide, adding 0.1wt.% carbon and annealed at 1700°C for two hours in hydrogen atmosphere. The X-ray diffraction analysis revealed the formation of rhombohedral LaAlO 3 crystallographic phase, however a small percentage (15%) of Al 2 O 3 has been also identified. The UV-Vis absorbance spectra were obtained and F and F + - center were ascribed. The UV irradiations were carried out using a commercial 8W UV lamp. Thermoluminescence measurements were performed at a Harshaw 4500 TL reader. All compositions investigated have shown high TL sensitivity to UVR. (author)

UV and gamma ray induced thermoluminescence properties of cubic Gd2O3:Er3+ phosphor

Directory of Open Access Journals (Sweden)

Raunak Kumar Tamrakar

2014-10-01

Full Text Available This paper reports the thermoluminescence properties of Er3+ doped gadolinium oxide nanophosphor. The phosphor is prepared by high temperature solid state reaction method. The method is suitable for large scale production. Starting materials used for sample preparation were Gd2O3, Er2O3 (0.5–2.5 mol% and fixed concentration of boric acid using as a flux. The prepared samples were characterized by X-ray diffraction technique and the particle size calculated by Scherer's formula. The surface morphology of prepared phosphor is determined by scanning electron microscopic (SEM technique. Functional group analysis was done by Fourier transform infra-red spectroscopy (FTIR analysis. The elemental analysis of prepared sample was determined by energy dispersive X-ray analysis (EDX and the exact particle size of prepared phosphor for the different concentration of dopant (Er3+ was evaluated by transmission electron microscopy (TEM technique. The prepared phosphors for different concentration of Er3+ were examined by thermoluminescence (TL glow curve for UV and gamma irradiation. The UV 254 nm source was used for UV irradiation and Co60 source was used for gamma irradiation. The samples show well resolved broad peak covered the temperature range 50–250 °C and the peak temperature found at 126 °C for UV irradiation and higher temperature peak at 214 °C for gamma irradiation. The effect of heating rate on TL studies was presented for optimized sample. Here UV irradiated sample shows the formation of shallow trap (surface trapping and the gamma irradiated sample shows the formation of deep trapping. The estimation of trap formation was evaluated by knowledge of trapping parameters. The trapping parameters such as activation energy, order of kinetics and frequency factor were calculated by peak shape method. Here most of the peak shows second order of kinetics. The effect of gamma and UV exposure on TL studies was also examined and it shows linear

Thermoluminescence characterization of CVD diamond film exposed to UV and beta radiation

International Nuclear Information System (INIS)

Barboza-Flores, M.; Melendrez, R.; Gastelum, S.; Chernov, V.; Bernal, R.; Cruz-Vazquez, C.; Brown, F.; Pedroza-Montero, M.; Gan, B.; Ahn, J.; Zhang, Q.; Yoon, S.F.

2003-01-01

Thermoluminescence (TL) properties of diamond films grown by microwave and hot filament CVD techniques were studied. The main purpose of the present work was to characterize the thermoluminescence response of diamond films to ultraviolet and beta radiation. The thermoluminescence excitation spectrum exhibits maximum TL efficiency around 210-215 nm. All samples presented a glow curve composed of at least one TL peak and showed regions of linear as well as supralinear behavior as a function or irradiation dose. The linear dose dependence was found for up to sixteen minutes of monochromatic UV irradiation and 300 Gy for beta irradiated samples. The activation energy and the frequency factor were determined and found in the range of 0.33-1.7 eV and 5.44 x 10 2 -5.67 x 10 16 s -1 , respectively. The observed TL performance is reasonable appropriate to justify further investigation of diamond films as radiation dosimeters keeping in mind that diamond is an ideal TL dosemeter since it is tissue-equivalent and biological compatible. (copyright 2003 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Observations on the activation energy determination through the peak temperature at the maximum in thermoluminescence (Tl) experiments

International Nuclear Information System (INIS)

Furetta, C.; Azorin, J.; Rivera, T.

2003-01-01

The aim of this work is to give, for practical purposes in routine works, an easy way for obtaining approximated values of E which can be useful for testing, in a very quick way, the stability of the trap levels corresponding to the dosimetric peak in thermoluminescent materials used for environmental, personnel and clinical dosimetry applications. Furthermore, the E values obtained with this method can be used as input data for deconvolution procedure. (Author)

The thermoluminescence of carp otoliths: A fingerprint in ...

African Journals Online (AJOL)

This paper reports a pilot study on the thermoluminescence (TL) of carbonate minerals of carp otoliths from the heavily polluted Baiyangdian Lake (BYD) in Hebei Province and non-polluted Miyun Water Reservoir (MY) in Beijing Municipality of China. Analyses on trace elements of otoliths and water show that the heavy ...

Investigation of dosimetric characteristics of the high sensitivity LiF:Mg,Cu,P Thermoluminescent Dosemeter and its applications in diagnostic radiology - a review

International Nuclear Information System (INIS)

Fung, K.L.

2004-01-01

This study investigated the dosimetric properties of the high sensitivity TLD (Thermoluminescent Dosemeter) of LiF:Mg,Cu,P and its applications in diagnostic radiology. A reproducible readout and annealing regime for this high sensitivity TLD was developed in the initial part of this study with the newly installed automatic TLD Reader system. Basic dosimetric characteristics of this T.L. dosemeter were then investigated. This paved the foundation for subsequent selected novel application studies in diagnostic radiology. This study exploits the favourable dosimetric properties of these T.L. dosemeters in some selected novel dosimetric applications in diagnostic radiology with an anthropomorphic phantom. The applications studied in radiological procedures included: dose reduction in lumbar spine radiography utilizing the 'anode heel effect'; gonad dose variation with kV p in chest radiography; foetal dose comparison between computed tomography (CT) and computed radiography (CR) in X-ray pelvimetry; lens dose reduction with bismuth eye-shields in CT brain studies; foetal dose assessment of early pregnancy in common high risk radiological examinations. It is anticipated that the unique and favourable dosimetric performance of LiF:Mg,Cu,P T.L. phosphor will be exploited further in measurements of low level dose received by patients and staff in diagnostic radiological procedures such as paediatric X-ray examinations

Investigation of dosimetric characteristics of the high sensitivity LiF:Mg,Cu,P Thermoluminescent Dosemeter and its applications in diagnostic radiology - a review

Energy Technology Data Exchange (ETDEWEB)

Fung, K.L. E-mail: orkarl@polyu.edu.hk

2004-05-01

This study investigated the dosimetric properties of the high sensitivity TLD (Thermoluminescent Dosemeter) of LiF:Mg,Cu,P and its applications in diagnostic radiology. A reproducible readout and annealing regime for this high sensitivity TLD was developed in the initial part of this study with the newly installed automatic TLD Reader system. Basic dosimetric characteristics of this T.L. dosemeter were then investigated. This paved the foundation for subsequent selected novel application studies in diagnostic radiology. This study exploits the favourable dosimetric properties of these T.L. dosemeters in some selected novel dosimetric applications in diagnostic radiology with an anthropomorphic phantom. The applications studied in radiological procedures included: dose reduction in lumbar spine radiography utilizing the 'anode heel effect'; gonad dose variation with kV{sub p} in chest radiography; foetal dose comparison between computed tomography (CT) and computed radiography (CR) in X-ray pelvimetry; lens dose reduction with bismuth eye-shields in CT brain studies; foetal dose assessment of early pregnancy in common high risk radiological examinations. It is anticipated that the unique and favourable dosimetric performance of LiF:Mg,Cu,P T.L. phosphor will be exploited further in measurements of low level dose received by patients and staff in diagnostic radiological procedures such as paediatric X-ray examinations.

A Study on the T L-Properties and Kinetics of Local Natural Calcium Fluoride

International Nuclear Information System (INIS)

Al-Saleh, F.S.

2006-01-01

Thermoluminescence characteristics of local natural calcium fluoride which is obtained from a flouride mine in the west of saudi arabia (shows a light purple appearance) have been studied. T L glow peaks are observed at 100,177,238 and 300 C.Thermal treatment and fading effects had been studied . the T L response is observed to increase with increasing dose, as expected, over the used dose range. the kinetic parameters were calculated to satisfy the feasibility of using the present sample as γ -ray dosimetry

Advances in the synthesis of new Europium doped CaSO4 phosphors and their thermoluminescence characterization

International Nuclear Information System (INIS)

Bernal, R.; Garcia-Haro, A.R.; Machi, L.; Brown, F.; Perez-Salas, R.; Castano, V.M.; Cruz-Vazquez, C.

2008-01-01

Novel self-agglomerating Eu doped CaSO 4 phosphors were synthesized by a cheap, easy, and environmental friendly chemical route. Pellet-shaped sintered samples were obtained without any binding material, and exposed to beta particle irradiation. The thermoluminescence (TL) response in the 0.08-2.6 Gy dose range increased linearly as the radiation dose increased. Glow curves exhibit the most intense maximum close to 200 deg. C, and two much less intense maxima at 250 and 330 deg. C when a 5 deg. C/s heating rate is used. No TL peaks shift is observed when dose changes, which is characteristic of first order kinetics TL processes. The whole glow curve displays a remarkable stability under storage at room temperature. The main peak intensity is 2.5 times greater than that of the TLD-100. The method here reported can be used to synthesize CaSO 4 with other dopants

Thermoluminescent characteristics of synthetic hydroxyapatite (SHAp)

International Nuclear Information System (INIS)

Alvarez, R.; Rivera, T.; Guzman, J.; Piña-Barba, M.C.; Azorin, J.

2014-01-01

This paper presents the experimental results of the thermoluminescent (TL) characteristics of synthetic hydroxyapatite (SHAp) obtained by the sol–gel method. For preparation of the SHAp powders, phosphorus pentoxide (P 2 O 5 ) and calcium nitrate tetrahydrated (Ca(NO 3 ) 2 –4H 2 O) were used. The powders obtained were submitted at different temperatures. The structural and morphological characterization were carried out using X-ray diffraction (XRD) and scanning electron microscopy techniques. TL glow curve exhibited two peaks centered at around 200 °C and 300 °C. TL response of SHAp as a function of gamma absorbed dose was linear over a wide dose range. Fading of the storage information in the samples irradiated was also studied. The experimental results show that the synthetic hydroxyapatite obtained by the sol–gel method may have used in gamma radiation dosimetry applications. - highlights: • Dosimetric characteristics of SHAp under gamma irradiation effect were analyzed • SHAp powders were obtained by Sol–Gel method • Fading anomalous of HAp was performed showing 15% during 90 days • SHAp showed good dosimetric characteristics. • Dosimetric characteristics of SHAp have not been reported yet in the literature before this paper

Phosphor for thermoluminescent type radiation dosimeter

International Nuclear Information System (INIS)

Nada, N.; Yamashita, T.

1975-01-01

This has the accumulation effect of radiation energy and is mainly used as the element for thermoluminescent type radiation dosimeters. It has as the principal constituent a phosphor consisting of calcium sulfate as the principal constituent and other impurity elements such as dysprosium, thulium and the like. It is more sensitive by the order of 1 to 2 or more figures than the conventional ones and is excellent in the retention of absorbed radiation energy. (U.S.)

A pocket type thermoluminescent personnel dosimeter

International Nuclear Information System (INIS)

Vora, K.G.; Nagpal, J.S.; Pendurkar, H.K.; Gangadharan, P.

1979-01-01

A pocket type thermoluminescent personnel dosemeter using CaSO 4 : Dy phosphor is described. Two glass capillaries containing the phosphor are fitted into a plastic tube and covered by a cylindrical filter. The combination is fitted into an ink barrel of a fountain pen. The response of this Dy glass dosimeter was studied for various incident photon energies. A uniform response over the energy range from 33 keV to 1250 keV is achieved. (A.K.)

Relative thermoluminescent efficiencies proton/gamma and helium/gamma of peaks of high temperature in TLD-100 dosemeters

International Nuclear Information System (INIS)

Flores M, E.

2007-01-01

The increase of the applications of ion beams in radiotherapy treatments has generated interest in the study of the thermoluminescent materials (TL) that allow to determine the applied doses. A way to quantify the TL response from these materials to ions is by means of the relative thermoluminescent efficiency. In the group of Thermoluminescent dosimetry of the Institute of Physics of the UNAM (IFUNAM) the thermoluminescent response of the TLD-100 dosemeters has been studied, which present a glow curve characteristic with several peaks that correspond to traps and luminescent centers in the material. The stable peaks know each other as 4, 5, 6a, 6b, 7, 8, 9 and 10. The efficiencies should be measured using the response so much to the radiation of interest (in this case protons and helium ions) as the response to gamma radiation. In previous works with ions of low energy taken place in the Pelletron accelerator of the IFUNAM was only measured the TL efficiency for the peak 5 and the total signal. It had not been possible to measure the efficiency of the peaks of high temperature (6a-10) because, for the gamma radiation, the peaks of high temperature show very small signals; however, recently Massillon carries out measures of efficiency TL of peaks of high temperature for ions of intermediate energy using a protocol special of reading and of deconvolution that allows to measure the signals coming from the peaks of high temperature. In this work is implemented this same protocol to complete the study of TL efficiencies at low energy of protons and helium and to determine if the values of efficiency depend on the used reading protocol. For it is reported it measures of the relative efficiency of the peaks of high temperature from the TLD-100 exposed to protons of 1.5 MeV and nuclei of helium of 3 and 7.5 MeV. (Author)

In vivo dosimetry with semiconductor and thermoluminescent detectors applied to head and neck cancer treatment

International Nuclear Information System (INIS)

Viegas, Claudio Castelo Branco

2003-03-01

In vivo dosimetry in radiotherapy, i. e, the assessment of the doses received by patients during their treatments, permits a verification of the therapy quality. A routine of in vivo dosimetry is, undoubtedly, a direct benefit for the patient. Unfortunately, in Brazil and in Latin America this procedure is still a privilege for only a few patients. This routine is of common application only in developed countries. The aim of this work is to show the viability and implementation of a routine in vivo dosimetry, using diodes semiconductors and thermoluminescent dosimeters (TLD), at the radiotherapy section of the National Institute of Cancer in Brazil, in the case of head and neck cancer treatment. In order to reach that aim, the characteristics of the response of diodes ISORAD-p and LiF:Mg;Ti (TLD-100) thermoluminescent detectors in powder form were determined. The performance of those detectors for in vivo dosimetry was tested using an RANDO Alderson anthropomorfic phantom and, once their adequacy proved for the kind of measurements proposed, they were used for dose assessment in the case of tumour treatments in the head and neck regions, for Cobalt-60 irradiations. (author)

Thermoluminescence dosimetry of gamma rays from the fallout of the Semipalatinsk nuclear tests

International Nuclear Information System (INIS)

Takada, J.; Hoshi, M.; Endo, S.; Yamamoto, M.; Nagatomo, T.; Gusev, B.I.; Rozenson, R.I.; Apsalikov, K.N.; Tchaijunusova, N.J.

1996-01-01

Field missions were sent to several settlements near the Semipalatinsk nuclear test site out in order to investigate dosimetry for the residents in 1995. The results of measurements of environmental radiation doses and thermoluminescence dosimetry in some villages near the Semipalatinsk nuclear test site are presented. The radiation levels in several villages are the natural background level in 1995, 6 years after the final nuclear explosion. On the other hand, thermoluminescence dosimetry revealed significant radiation exposure to residents in this area due to nuclear tests. (author)

Image in nuclear dosimetry using thermoluminescent dosimetry

International Nuclear Information System (INIS)

Guinsburg, G.; Matsuoka, M.; Watanabe, S.

1987-01-01

A low cost methodology to produce images of internal sick organs by radioisotopic intake, is presented. Dosimetries of thermoluminescent material and Teflon (ratio:50%) in bidimensional matrix shape are used with a Pb collimator. This collimator-bidimensional matrix system was tested ''in vivo'' and in thyroid phantoms using 99m Tc. A comparative evaluation between this method and the scintigraphy one is presented. (M.A.C.) [pt

Thermoluminescent properties of CaSO4:Dy prepared by precipitation method

International Nuclear Information System (INIS)

Roman, J.; Rivera, T.; Azorin, J.

2009-10-01

This paper reports the synthesis and thermoluminescent (Tl) characterization of CaSO 4 :Dy obtained by the precipitation method. Thermoluminescent CaSO 4 :Dy powder and Teflon (PTFE) were mixed in order to obtain samples in pellets form. Samples of CaSO 4 :Dy were exposed to a radiation gamma source of 60 Co and 90 Sr beta particles. Tl response of CaSO 4 :Dy showed a glow curve with two peaks centered at around 164 and 302 C. Tl phosphor showed a good linearity in the range from 0.5 to 30 Gy. Fading of the Tl information was 5.19 % in 37 days and presented a standard deviation of 4% for reproducibility. (Author)

Thermoluminescence dating of late Devensian loesses in southern England

International Nuclear Information System (INIS)

Wintle, A.G.

1981-01-01

The results are reported of thermoluminescence dating of six relatively recent deposits of loess-like material from southern Britiain between the Scilly Isles and Kent. The dates have been obtained on the loess itself and confirm the ages as being late Devensian. (U.K.)

Experimental dosimetry and kinetics of radioactive tracers for human applications: example of therapeutic injection of Lipiodol labelled with Iodine 131

International Nuclear Information System (INIS)

Ahmed Mahidi, N.

1992-10-01

We have evaluated the radiation dose received by the liver and lungs for 10 patients with a hepatic carcinoma after surgical operation followed by a therapeutic dose of Lipiodol labelled with iodine 131. The cumulated activities have been obtained by using a calibrated gamma camera. Fixation and kinetics of the I 131 Lipiodol in normal and cancers livers have been measured with the determination of the effective and biological half-lives. The calculated doses are based on the MIRD method. Results confirm that Lipiodol fixation is important in the liver at J1 (about 74% of the injected activity). Its elimination is essentially urinary, pulmonary fixation remained low, the dose received by the healthy part of liver is acceptable. These values have been compared with those obtained by another method using a thermoluminescent dosimeter (LiF) installed on the skin over the liver. Comparison between results obtained by the 2 methods shows a good correlation

Thermoluminescence: how safe are we? ask the crystals

International Nuclear Information System (INIS)

Madiyal, Ananya; Alva, Priyadharshini

2013-01-01

Thermoluminescence means 'light emitted from heat'. Thermoluminescent dosimeter (TLD) is a type of radiation measuring instrument used for the measurement of actual dose received by the operator or patient as a result of radiographic exposure. TLD calculates the ionising radiation exposure by measuring the amount of visible light emitted from a crystal in the detector when the crystal is heated. The two types of TLD are Calcium Fluoride type and the Lithium Fluoride type. The former is used for environmental detection of radiation exposure while the latter is used for detection of personal radiation exposure. A TLD card consists of a nickel plated aluminium plate and 3 filters. The equipment used to heat the exposed material and measure the emitted light produced by heat is called TLD reader. It comprises of a heater, a photomultiplier tube and the electronic system. TLD is used to measure the dose received by a patient while undergoing radiotherapy, for radio-diagnosis and as personnel monitoring devices. It has the advantage of being small in size, chemically inert, accurate and gives a reproducible reading. (author)

An experimental system for thermoluminescent dosimetry

International Nuclear Information System (INIS)

Perry, K.E.G.; George, E.

1965-08-01

A thermoluminescent dosimeter (T.L.D.) reader has been developed for experimental investigations on the use of lithium fluoride for 'finger tip' dosimetry. The design of the reader is based on the maximum use of standard electronic units in the A.E.R.E. Type 2000 series but some new unit development has been necessary. The reader gives improved experimental facilities over present commercially-available designs. The technique for 'finger-tip' dosimetry is described and the initial experimental results are given. (author)

Application of EPR, thermoluminescence as well as DNA damage examination methods and sprout inhibition for identification of irradiated food

International Nuclear Information System (INIS)

Malec-Czechowska, K.; Stachowicz, W.; Dancewicz, A.M.; Szot, Z.

1998-01-01

Irradiation of food with doses up to 10 kGy of gamma, X-rays or electron beam is a relatively new technology improving hygienic quality of food, diminishing morbidity due to food pathogens and reducing losses during food storage. Application of this technology increases constantly in the world; more and more irradiated food appears on the market in various countries. In Europe it is agreed notion that detection of irradiated foods should be obligatory procedure included into administrative control system of foodstuffs. For this purpose the reliable methods are needed by which detection of irradiation fact will be possible. Such methods are not easy to be worked out because irradiation induces changes which are to small to be detected by methods commonly applied for food control. Working out the methods suitable for identification of irradiated food has been carried out in many countries in the world and during the last decade within several local and/or international programmes including the intercomparison of results obtained in different laboratories. In our institute such investigations began already in the 80-ties using EPR spectrometry and thermoluminescence measurements. Applications of these methods were approved in 1996 as European Community Standards. Other methods are still under investigation. They include the analyses of DNA damage in irradiated foodstuffs of animal or plant origin and measurements of germination effectiveness of irradiated grains and fruits. In this communication we present some results obtained upon application of forementioned methods to detection of different kinds of food irradiated with gamma rays or electron beam. (author)

Thermoluminescence properties of Li2B4O7:Cu, B phosphor synthesized using solution combustion technique

International Nuclear Information System (INIS)

Ozdemir, A.; Altunal, V.; Kurt, K.; Depci, T.; Yu, Y.; Lawrence, Y.; Nur, N.; Guckan, V.; Yegingil, Z.

2017-01-01

To determine the effects of various concentrations of the activators copper (Cu) and boron (B) on the thermoluminescence (TL) properties of lithium tetraborate, the phosphor was first synthesized and doped with five different concentrations of copper (0.1–0.005 wt%) using solution combustion method. 0.01 wt% Cu was the concentration which showed the most significant increase in the sensitivity of the phosphor. The second sort of Li 2 B 4 O 7 :Cu material was prepared by adding B (0.001–0.03 wt%) to it. The newly developed copper-boron activated lithium tetraborate (Li 2 B 4 O 7 :Cu, B) material with 0.01 wt% Cu and 0.001 wt% B impurity concentrations was shown to have promise as a TL phosphor. The material formation was examined using powder x-Ray Diffraction (XRD) analysis and Scanning Electron Microscope (SEM) imaging. Fourier Transform Infrared (FT-IR) spectrum of the synthesized polycrystalline powder sample was also recorded. The TL glow curves were analyzed to determine various dosimetric characteristics of the synthesized luminophosphors. The dose response increased in a “linear” way with the beta-ray exposure between 0.1–20 Gy, a dose range being interested in medical dosimetry. The response with changing photon and electron energy was studied. The rate of decay of the TL signal was investigated both for dark storage and under direct sunlight. Li 2 B 4 O 7 :Cu, B showed no individual variation of response in 9 recycling measurements. The fluorescence spectrum was determined. The kinetic parameters were estimated by different methods and the results discussed. The studied properties of synthesized Li 2 B 4 O 7 :Cu, B were found all favorable for dosimetric purposes. - Highlights: • Li 2 B 4 O 7 :Cu, B synthesis using solution combustion method with various concentrations. • Structure analysis of Li 2 B 4 O 7 :Cu, B using XRD, SEM and FTIR methods. • Investigation of thermoluminescent properties of Li 2 B 4 O 7 :Cu, B. • Relatively good

A method for reducing energy dependence of thermoluminescence dosimeter response by means of filters

International Nuclear Information System (INIS)

Bapat, V.N.

1980-01-01

This work describes the application of the method of partial surface shielding for reducing the energy dependence of the X-ray and γ-ray response of a dosimeter containing a CaSO 4 :Dy thermoluminescent phosphor mixed with KCl. in pellet form. Results are given of approximate computation of filter combinations that accomplish this aim, and of experimental verifications. Incorporation of the described filter combination makes it possible to use this relatively sensitive dosimeter for environmental radiation monitoring. A similar approach could be applied to any type of dosimeter in the form of a thin pellet or wafer. (author)

Semi-empirical simulation of thermoluminescent response under different filter geometries

International Nuclear Information System (INIS)

Shammas, Gabriel Issa Jabra

2006-01-01

Many thermoluminescent materials has been developed and used for photon personal dosimetry but no one has all desired characteristics alone. These characteristics include robustness, high sensitivity, energy photon independence, large range of photon energy detection, good reproducibility, small fading and simple glow curve with peaks above 150 deg C. Calcium Sulfate Dysprosium doped (CaSO 4 :Dy) phosphor Thermoluminescent Dosimeter (TLD) has been used by many laboratories, mainly in Brazil and India. Another interesting phosphor is Calcium Fluoride (CaF 2 ). These phosphor advantages begin to be more required and its disadvantages have became more apparent, in a global market more and more competitive. These phosphors are used in environmental and area monitoring, once they present more sensibility than other phosphors, like LiF:Mg. Theirs mainly disadvantage is a strong energetic dependence response, which must be corrected for theirs application in the field, where photon radiation is unknown a priori. An interesting way do make this correction in orthogonal incidence of the radiation on the phosphor is to interject a plane leaked filter between the beam and the phosphor. In order to reduce the energetic dependence on any incidence angle, reducing the field dose measurement uncertainty too, this work presents a simulation study on spherical filter geometries. It was simulated photon irradiations with Gamma rays of 60 Co and x-rays of 33; 48 and 118 keV, on many incidence angles from zero to ninety degrees. These semi-empirical computational simulations using finite differences in three dimensions were done in spherical coordinates. The results pointed out the best filter thicknesses and widths, in order to optimize the correction on energetic dependence. (author)

Performance tests on the NRPB thermoluminescent dosemeter

CERN Document Server

Shaw, K B

1977-01-01

Performance tests on the thermoluminescent dosemeter, designed at NRPB for use in the automated personal dosimetry system, are described. An ultra-thin lithium borate dosemeter has been developed for skin absorbed dose measurement. The X-ray, gamma-ray and beta-ray energy response of the dosemeter has been investigated and the angular response for the dosemeter has been examined. The annealing, read-out and stabilisation procedures for the dosemeter are described.

Spatially-resolved thermoluminescence from snail opercula using an EMCCD

DEFF Research Database (Denmark)

Duller, G.A.T.; Kook, Myung Ho; Stirling, R.J.

2015-01-01

In recent years opercula of the snail species Bithynia tentaculata have been shown to emit thermoluminescence (TL) signals that can be used to determine equivalent dose, and may be capable of dating events throughout the entire Quaternary period. Concentric growth lines are a notable feature of a...

Observations on some thermoluminescence emission centres in geological quartz

International Nuclear Information System (INIS)

Scholefield, R.B.; Prescott, J.R.; Fox, P.J.; Franklin, A.D.

1994-01-01

We report measurements of three-dimensional thermoluminescence emission spectra of samples of geological quartz, derived from Australian sediments. The emphasis is on peaks of particular practical interest for thermoluminescence sediment dating, viz. the 110 o C peak, which is used for pre-dose dating and the peak at 325 o C, which is of significance for partial and selective bleach techniques and for optically stimulated luminescence (OSL) dating. Because the 325 o C peak can be bleached to essentially zero, it can be isolated in a given spectrum by subtracting the bleached spectrum from the unbleached spectrum. By including both peaks in the same spectrum, it is demonstrated that they do not emit at the same wavelength, although this does not necessarily mean that the emission is from different emission centres. The 375 o C peak, which is important in total bleach methods, emits at a distinguishable wavelength. The use of bleaching and subtraction in practical dating is discussed. (Author)

Comparative study of thermoluminescence detection methods for irradiated spices

International Nuclear Information System (INIS)

Kawamura, Y.; Kojima, K.; Sugita, T.; Yamada, T.; Saito, Y.

1995-01-01

The thermoluminescence (TL) detection methods for irradiated spices were compared using spice samples obtained on the Japanese market, irradiated at doses of 1, 5, 10 and 30 kGy and stored for 1 year before analysis. The TL intensities of irradiated spices were stable for 1 year after irradiation. Measurement with whole samples failed to identify irradiated samples. Minerals were separated from spices in sodium tungstate saturated solution and/or sodium polytungstate solution. The TL intensity of minerals which had undergone irradiation was significantly increased for all samples. However, the ranges of TL intensity of irradiated and unirradiated samples overlapped. Clear discrimination has been obtained between the TL ratios of irradiated and unirradiated spices by using normalized measurement with reirradiation. The detection limit in terms of irradiation dose is 1 kGy even in a sample that has been irradiated 1 year prior to analysis. Normalization is the best technique currently available for thermoluminescence analysis to identify irradiated spices

Leaked filters for energetic and angular dependence corrections of thermoluminescent response

International Nuclear Information System (INIS)

Manzoli, Jose Eduardo; Shammas, Gabriel Issa Jabra; Campos, Vicente de Paulo de

2007-01-01

Many thermoluminescent materials has been developed and used for photon personal dosimetry but no one has all desired characteristics alone. These characteristics include robustness, high sensitivity, energy photon independence, large range of photon energy detection, good reproducibility and small fading. The phosphors advantages begin to be more required and its disadvantages have became more apparent, in a global market more and more competitive. Calcium Sulfate Dysprosium doped (CaSO 4 :Dy) and Calcium Fluoride Manganese doped (CaF 2 :Mn) phosphor Thermoluminescent Dosimeters (TLDs) have been used by many laboratories. They are used in environmental and area monitoring, once they present more sensibility than other phosphors, like LiF:Mg. Theirs main disadvantage is the strong energetic dependence response, which must be corrected for theirs application in routine, where the kind of photon radiation is unknown a priori. An interesting way to make this correction is to interject a leaked filter between the beam and the phosphor, where the beam could strike the phosphor at any angle. In order to reduce the energetic dependence on any incidence angle, this work presents experimental and simulation studies on some filter geometries. It was made TL readings and simulations on TL responses to photon irradiations with gamma rays of 60 Co and X-rays of 33; 48 and 118 keV, on many incidence angles from zero to ninety degrees. The results pointed out the best filter thicknesses and widths, in order to optimize the correction of energetic dependence for the studied geometries. (author)

Thermoluminescence in films of HfO{sub 2}:Dy{sup +3}; Termoluminiscencia en peliculas de HfO{sub 2}:Dy{sup +3}

Energy Technology Data Exchange (ETDEWEB)

Ceron, P.; Rivera, T.; Guzman, J.; Montes, E.; Pelaez, A.; Rojas, B.; Guzman, D. [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Legaria No. 694, Col. Irrigacion, 11500 Mexico D. F. (Mexico); Azorin, J. [Universidad Autonoma Metropolitana, Unidad Iztapalapa, San Rafael Atlixco 186, Col. Vicentina, 09340 Mexico D. F. (Mexico); Paredes, L., E-mail: victceronr@hotmail.com [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

2014-08-15

In this work the thermoluminescence (TL) response of films of hafnium oxide polluted with dysprosium (HfO{sub 2}:Dy{sup +3}) that were irradiated in the near UV (200 nm - 400 nm). The films were deposited by means of the ultrasonics spray pyrolysis technique on a glass substrate, using different deposit temperatures (300 grades C - 600 grades C). The best TL emission corresponded to the prepared film to 450 grades C that was exposed to a spectral irradiation of 80 μJ/(cm{sup 2}-s) with a wave longitude of 240 nm. The TL response in function of the spectral irradiation was lineal in the studied interval (24 to 288 mJ/cm{sup 2}), several kinetic parameters were also calculated of the shine curve as depth of the trap (E), frequency factor (s) and order to the kinetics (b). The obtained results show that the films of HfO{sub 2}:Dy{sup +3} could be used as radiation monitor in the region of the near UV. (Author)

Thermoluminescent dosemeters characterization for patient dosimetry in diagnostic radiology preliminary results

International Nuclear Information System (INIS)

Castro, William J.; Squair, Peterson L.; Gonzaga, Natalia B.; Nogueira, Maria S.; Silva, Teogenes A. da

2009-01-01

The determination of the metrological characteristics of thermoluminescent (TL) dosimeters plays an important role in dosimetry of patients submitted to x-ray examinations for diagnostic purpose. Entrance surface doses can be measured with TL dosimeters to verify the compliance with the diagnostic reference levels. Organ doses can be estimated through TL measurements in an anthropomorphic phantom which it allows the radiation risk assessment. In this work, LiF:Mg,Ti (TLD-100) rod and chip thermoluminescent dosimeters were characterized considering their use for patient dosimetry in computerized tomography and mammography. Preliminary results showed that TL dosimeters have a response reproducibility of 7.8% and 4.8% and homogeneity of 18.4% and 6.5% for rod and chip shapes, respectively. (author)

Persistent luminescence and thermoluminescence of UV/VIS -irradiated SrAl2O4: Eu2+, Dy3+ phosphor

International Nuclear Information System (INIS)

Pereyda-Pierre, C.; Meléndrez, R.; García, R.; Pedroza-Montero, M.; Barboza-Flores, M.

2011-01-01

The persistent luminescence and thermoluminescence properties of SrAl 2 O 4 : Eu 2+ , Dy 3+ phosphors excited with UV–VIS light in the 200–500 nm region were investigated. The thermoluminescence glow curve was found to be composed of peaks around 70, 125 and 245 °C. The persistent luminescence and thermoluminescence excitation spectra exhibited a broad band around 300–500 nm centered at 400 and 420 nm respectively. A linear behavior of the integrated thermoluminescence intensity and persistent luminescence versus irradiation time was found for the first 60 s. The charge detrapping from the 70 °C trapping levels was the major contributor to the observed persistent luminescence at room temperature. The SrAl 2 O 4 : Eu 2+ , Dy 3+ phosphors have suitable properties to be applied as storage and persistent luminescence UV–VIS irradiation dose phosphor. -- Highlights: ► SrAl 2 O 4 :Eu 2+ , Dy 3+ persistent luminescence and thermoluminescence was measured. ► The phosphor was irradiated with UV–VIS photons in the 200–500 nm wavelength range. ► SrAl 2 O 4 :Eu 2+ , Dy 3+ behaves adequately as persistent and storage UV–VIS dosimeter. ► The persistent luminescence dosimetry does not require heat or light stimulation.

Dating of pre hispanic ceramics from the archaeological zone of Zoque by thermoluminescence method

International Nuclear Information System (INIS)

Valdes, J.V.; Gonzalez, P.R.; Mendoza, D.; Tenorio, D.; Terreros, E.; Ramirez, A.

2007-01-01

Full text: The dating of pre hispanic ceramics resides permitting us to located them in a certain period of the history; allows us to verify it origin. The thermoluminescence is a technique that permits us to estimate the absolute age of the archaeological samples. The present work is directed in determining the age by the method of thermoluminescence of archaeological samples of the grotto of Concubac, located in the Serrana Region of Tabasco. To determine the mineralogical composition of the samples, analysis of diffraction of X rays and Energy Dispersive X-ray Spectroscopy (EDS) have been conducted. The radiation emitted by the ground where the samples were buried and the contribution of the cosmic radiation was measured with thermoluminescent dosimeters of LiF:Mg,Cu,P+PTFE. The feasibility of dating of the studied samples is broadly disputed in function of the contents of minerals, as well as the procedure and management of the sample. (Author)

Transport phenomena and kinetic theory applications to gases, semiconductors, photons, and biological systems

CERN Document Server

Gabetta, Ester

2007-01-01

The study of kinetic equations related to gases, semiconductors, photons, traffic flow, and other systems has developed rapidly in recent years because of its role as a mathematical tool in many applications in areas such as engineering, meteorology, biology, chemistry, materials science, nanotechnology, and pharmacy. Written by leading specialists in their respective fields, this book presents an overview of recent developments in the field of mathematical kinetic theory with a focus on modeling complex systems, emphasizing both mathematical properties and their physical meaning. The overall presentation covers not only modeling aspects and qualitative analysis of mathematical problems, but also inverse problems, which lead to a detailed assessment of models in connection with their applications, and to computational problems, which lead to an effective link of models to the analysis of real-world systems. "Transport Phenomena and Kinetic Theory" is an excellent self-study reference for graduate students, re...

Report on a workshop on the application of thermoluminescence dosimetry to large scale individual monitoring, Ispra, 11-13 September 1985

International Nuclear Information System (INIS)

Barthe, J.R.; Christensen, P.; Driscoll, C.M.H.; Marshall, T.O.; Harvey, J.R.; Julius, H.W.; Marshall, M.; Oberhoffer, M.

1987-01-01

The workshop was held for the benefit of those actually involved in the operation of large scale automatic thermoluminescence dosimetry systems. It was organised around three overall themes subdivided into 13 subject headings: External constraints: User requirements, Quantities and Units, Legal requirements, Testing, Intercomparisons; Dosimetry systems: Materials, Dosemeter design, Reading systems, Annealing procedures, Rogue readings; Management: Distribution and organisation, Reporting and record keeping, Financial aspects. (author)

Thermoluminescence glow curve for UV induced ZrO2:Ti phosphor with variable concentration of dopant and various heating rate

Directory of Open Access Journals (Sweden)

Neha Tiwari

2014-10-01

Full Text Available The present paper reports the synthesis and characterization of Ti doped ZrO2 nanophosphors. The effects of variable concentration of titanium on thermoluminescence (TL behaviour are studied. The samples were prepared by combustion a synthesis technique which is suitable for less time taking techniques also for large scale production for nano phosphors. The starting material used for sample preparation are Zr(NO33 and Ti(NO33 and urea used as a fuel. The prepared sample was characterized by X-ray diffraction technique (XRD with variable concentration of Ti (0.05–0.5 mol% there is no any phase change found with increase the concentration of Ti. Sample shows cubic structure and the particle size calculated by Scherer's formula. The surface morphology of prepared phosphor was determined by field emission gun scanning electron microscopy (FEGSEM technique for optimized concentration of dopant. The good connectivity with grains and the semi-sphere like structure was found by FEGSEM. The functional group analysis was determined by Fourier transform infrared (FTIR spectroscopic techniques. The prepared phosphor examined by thermoluminescence technique. For recording TL glow curve every time 2 mg phosphor was irradiated by UV 254 nm source and fixed the heating rate at 5 °C s−1. Sample shows well resolved peak at 167 °C with a shoulder peak at 376 °C. The higher temperature peak shows the well stability and less fading in prepared phosphor. Also the effect of Ti concentration at fixed UV exposure time was studied. The effect of UV exposure time and dose versus intensity plot was studied. Sample shows linear response with dose and broaden peak with high temperature shows the more stability and less fading in TL glow curve. The linear dose response, high stability and less fading phenomenon shows the sample may be useful for thermoluminescence dosimetry application. Trapping parameters are calculated for every recorded glow curve. The

Physical principles of thermoluminescence and recent developments in its measurement

International Nuclear Information System (INIS)

Levy, P.W.

1974-01-01

The physical principles which are the basis of thermoluminescence techniques for dating and authenticating archaeological and fine art objects are described in non-technical terms. Included is a discussion of the interaction of alpha particles, beta rays, i.e., energetic electrons, and gamma rays with solids, particularly electron-hole ion pair formation, and the trapping of charges by crystal imperfections. Also described is the charge-release process induced by heating and the accompanying emission of luminescence resulting from charge recombination and retrapping. The basic procedure for dating and/or authenticating an artifact is described in a ''how it is done'' manner. Lastly, recently developed apparatus is described for simultaneously measuring luminescent light intensity and wavelength and sample temperature. Examples of studies made with this ''3-D'' apparatus are given and applications to dating and authenticating are described. (U.S.)

Evaluation of glasses containing cadmium for high dose dosimetry by the thermoluminescence technique

International Nuclear Information System (INIS)

Carvalho, Gabriel Soares Marchiori de; Ferreira, Pamela Zati; Cunha, Diego Merigue da; Dantas, Noelio Oliveira; Silva, Anielle C.A.; Perini, Ana Paula; Neves, Lucio Pereira; Carrera, Betzabel Noemi Silva; Watanabe, Shigueo

2016-01-01

New glass matrices were evaluated for high dose dosimetry by the thermoluminescence technique. Their nominal composition are 20Li_2CO_3.10Al_2O_3.15CdO.55B_2O_3 and 20Li_2CO_3.10Al_2O_3.20CdO.50B_2O_3 (mol%). The glass matrices were irradiated with different doses: 50, 100, 200, 500, 700 and 900 Gy, and the thermoluminescence emission curves were obtained for each of these values. The results show a great potential of using these matrices in high dose dosimetry. (author)

Kinetic parameters and TL mechanism in cadmium tetra borate phosphor

International Nuclear Information System (INIS)

Annalakshmi, O.; Jose, M.T.; Sridevi, J.; Venkatraman, B.; Amarendra, G.; Mandal, A.B.

2014-01-01

Polycrystalline powder samples of cadmium tetra borate were synthesized by a simple solid state sintering technique and gamma irradiated sample showed a simple Thermoluminescence (TL) glow peak around 460 K. The TL kinetic parameters of gamma irradiated phosphor were determined by initial rise (IR), isothermal decay (ID), peak shape (PS), variable heating rate (VHR) and glow curve de-convolution method. The kinetic parameters such as activation energy (E), frequency factor (s) and order of kinetics (b) were calculated by IR, ID, PS and VHR methods are in the order of ∼1.05 eV, 10 9 –10 12 s −1 and 1.58, respectively. From the results of TL and PL emission studies carried out on the phosphor revealed that the defect centers related to TL is different from that for PL. EPR measurements were carried out to identify the defect centers formed in cadmium tetra borate phosphor on gamma irradiation. Based on EPR studies the mechanism for TL process in cadmium tetra borate is proposed in this paper -- Highlights: • Polycrystalline powder samples of undoped cadmium tetra borate synthesized. • Cadmium tetra borate phosphor exhibits a dosimetric peak at 458 K. • Kinetic parameters of the trap responsible for TL evaluated. • TL mechanism is proposed from TL to EPR correlation studies

Kinetic parameters and TL mechanism in cadmium tetra borate phosphor

Energy Technology Data Exchange (ETDEWEB)

Annalakshmi, O. [Radiological Safety Division, Materials Physics Division, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102 (India); Jose, M.T., E-mail: mtj@igcar.gov.in [Radiological Safety Division, Materials Physics Division, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102 (India); Sridevi, J. [Central Leather Research Institute, Council of Scientific and Industrial Research, Chennai 600 020, Tamilnadhu (India); Venkatraman, B. [Radiological Safety Division, Materials Physics Division, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102 (India); Amarendra, G. [Materials Physics Division, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102 (India); Mandal, A.B. [Central Leather Research Institute, Council of Scientific and Industrial Research, Chennai 600 020, Tamilnadhu (India)

2014-03-15

Polycrystalline powder samples of cadmium tetra borate were synthesized by a simple solid state sintering technique and gamma irradiated sample showed a simple Thermoluminescence (TL) glow peak around 460 K. The TL kinetic parameters of gamma irradiated phosphor were determined by initial rise (IR), isothermal decay (ID), peak shape (PS), variable heating rate (VHR) and glow curve de-convolution method. The kinetic parameters such as activation energy (E), frequency factor (s) and order of kinetics (b) were calculated by IR, ID, PS and VHR methods are in the order of ∼1.05 eV, 10{sup 9}–10{sup 12} s{sup −1} and 1.58, respectively. From the results of TL and PL emission studies carried out on the phosphor revealed that the defect centers related to TL is different from that for PL. EPR measurements were carried out to identify the defect centers formed in cadmium tetra borate phosphor on gamma irradiation. Based on EPR studies the mechanism for TL process in cadmium tetra borate is proposed in this paper -- Highlights: • Polycrystalline powder samples of undoped cadmium tetra borate synthesized. • Cadmium tetra borate phosphor exhibits a dosimetric peak at 458 K. • Kinetic parameters of the trap responsible for TL evaluated. • TL mechanism is proposed from TL to EPR correlation studies.

Thermoluminescence study of lithium fluorides

CERN Document Server

Abu-Alazm, S M

2003-01-01

The spectrum of the light emitted during thermoluminescence (TL) from irradiated lif sample with different doses of Xe, Kr and electrons have been studied. The results show a main peak for all samples irradiated and unirradiated at temperature about 200 degree C. Morcever when the reaches to the value 5x10 sup 1 1 ion/cm sup 2 a new two bands begin to appear in case of Xe and Kr ion irradiation. The TL spectra under Kr and Xe ion irradiation similar at the same dose. However, the spectra under electron irradiation were found to be rather different than under heavy ions irradiation.

Investigation and measurement of radio thermoluminescence properties of some calci tic mollusc shells of the Persian Gulf and the Oman Sea (for γ radiation dosimetry)

International Nuclear Information System (INIS)

Ghafourian, H.; Rabbani, M.; Rouhi, U.

2000-01-01

Biogenic Calcium Carbonate, particularly as naturally thermoluminescent calci tic mollusc shells may serve as excellent radio thermoluminescent dosimeters. In this study the radio thermoluminescence properties of 8 different bivalves of the Persian Gulf, the Oman Sea and the internal calcite shell of Sepia sp. are investigated. The results of this investigation have shown that the shells of Sepia sp., Pinctata radiata and Card ita bicolor as appropriate dosimeters for both personal and industrial dosimetry purposes, among which Sepia sp. is the most sensitive one. Callista umbonella and Mactra sp. are relatively less thermoluminescent while Saccostrea Cucullata and Chlamys ruschenbergerii are completely inert with respect to γ - thermoluminescence. Thermoluminescence properties of Anadara refescens and Anadara secticostata decrease surprisingly by an increase in the absorbed dose of γ radiation, which can mainly be interpreted as the result of crystal lattice destruction caused by ionizing radiation

Polynomial expressions of electron depth dose as a function of energy in various materials: application to thermoluminescence (TL) dosimetry

Energy Technology Data Exchange (ETDEWEB)

Deogracias, E.C.; Wood, J.L.; Wagner, E.C.; Kearfott, K.J

1999-02-11

The CEPXS/ONEDANT code package was used to produce a library of depth-dose profiles for monoenergetic electrons in various materials for energies ranging from 500 keV to 5 MeV in 10 keV increments. The various materials for which depth-dose functions were derived include: lithium fluoride (LiF), aluminium oxide (Al{sub 2}O{sub 3}), beryllium oxide (BeO), calcium sulfate (CaSO{sub 4}), calcium fluoride (CaF{sub 2}), lithium boron oxide (LiBO), soft tissue, lens of the eye, adiopose, muscle, skin, glass and water. All materials data sets were fit to five polynomials, each covering a different range of electron energies, using a least squares method. The resultant three dimensional, fifth-order polynomials give the dose as a function of depth and energy for the monoenergetic electrons in each material. The polynomials can be used to describe an energy spectrum by summing the doses at a given depth for each energy, weighted by the spectral intensity for that energy. An application of the polynomial is demonstrated by explaining the energy dependence of thermoluminescent detectors (TLDs) and illustrating the relationship between TLD signal and actual shallow dose due to beta particles.

Thermoluminescence detected in Magicicada sp. exoskeletons

International Nuclear Information System (INIS)

Fields, D.E.; Randall, R.B.; Bauman, C.E. III

1979-01-01

Thermoluminescent emission from the irradiated exoskeletons of cicada have been observed. At a heating rate of approximately 60 0 C/min. the peak light emission temperature was 183 +- 3 0 C. This effect corresponds to charge-carrier trap parameters of Esub(a) = 0.82 +- 0.04 eV and w 0 = 10sup(9.1 +- 0.5) sec -1 . Response to filtered γ radiation of 50-kV peak energy was on the order of 3.2 x 10 6 photons/R/g. Insect exoskeletons are thus potentially useful as dosimeters. (author)

Quality control of dosimetric systems using thermoluminescent crystals

International Nuclear Information System (INIS)

Mahecha, L.; Plazas, M. C.; Machado, M.; Perea, M. D.

2006-01-01

To achieve an optimal tumoral control to prostate cancer in early and locally advanced stages, it is necessary to increase the dose with a low mobility probability at the vesicle an rectal level. This is achieved through conformal radiotherapy. The Instituto Nacional de Cancerologia uses this technique, but two questions arise from the medical-physicists and medical radio-oncologist: In accordance with clinical protocols, the conformal radiotherapy delivers a low dose to the adjacent healthy tissues. What experimental method exists that can prove with certainly the veracity of this affirmation?. And, Do the dosimetric simulation system calculate suitable the dose for each tissues?. Through thermoluminescent dosimetry and the use of a physical simulator,we measured the absorbed dose at the target volume and the adjacent tissues using conformal and conventional radiotherapy. We proved that organs such as the rectum and bladder, receiver a minor dose in conformal radiotherapy, hence reducing their mobility probability. In addition, the readings from the thermoluminescent dosimeters and the doses calculated by the ECLIPSE dosimetric system were compared, concluding that the patient's prescribed dose is effectively delivered as recommended by the quality control program in radiotherapy. (Author)

Thermoluminescence of double fluorides doped with rare earths

International Nuclear Information System (INIS)

Azorin N, J.; Sanchez R, A.; Khaidukov, N.M.

2004-01-01

In this work the thermoluminescent characteristics of double fluorides K 2 YF 5 , K 2 GdF 5 and K 2 LuF 5 doped are presented with Tb 3+ , studied in the interval of temperature from 30 to 400 C. The materials that presented better answer to the irradiation with particles beta and with ultraviolet light they were the K 2 YF 5 : Tb (1% at. Tb 3+ ) and the K 2 LuF 5 : Tb (1% at. Tb 3+ ); while the K 2 YF 5 : Tb to high concentrations (10% and 20% at. Tb 3+ ) and the K 2 LuF 5 : Tb (1% at. Tb 3+ ) and the K 2 LuF 5 : Tb (1% at. Tb 3+ ) they presented an acceptable answer in front of the gamma radiation. The intensity of the Tl answer induced in these materials is a decisive factor to continue studying its dosimetric characteristics, what allows to consider them as the base for the development of potential materials to use them in the dosimetry of beta particles, of the UV light of the gamma radiation using the thermoluminescence method. (Author)

Thermoluminescence induced by X-rays in silica materials with metallic impurities

International Nuclear Information System (INIS)

Mendoza A, D.; Gonzalez M, P.; Espinosa P, M.; Salas, P.; Castano, V.M.

1999-01-01

Diverse materials of silica with Fe, Cu, Mg, and Mn impurities were synthesized by the sol-gel method, using tetraethyl orthosilicate as precursor. The materials obtained were subjected to thermal treatment at 500, 700 and 1000 Centigrade also they were irradiated with X-ray generated by a X-ray diffractometer which is installed in the ININ. The thermoluminescent signal was analysed and correlated with the type of impurities that are present in the material and with the grade of crystallinity produced by the thermal treatment in them. In according to the results obtained these materials show a thermoluminescent signal which is influenced by the crystallinity grade. It was analysed the behavior of the response for different doses, with the purpose of utilizing them to quantify very intense fields of radiation. (Author)

Thermoluminescence dating

International Nuclear Information System (INIS)

Price, D.M.

1999-01-01

Thermoluminescence (TL) dating of sediments depends upon the acquisition and long term stable storage of TL energy by crystalline minerals contained within a sedimentary unit. This energy is stored in the form of trapped electrons and quartz sand is the most commonly used mineral employed in the dating process. Prior to the final depositional episode it is necessary that any previously acquired TL is removed by exposure to sunlight. After burial the TL begins to build up again at a rate dependent upon the radiation flux delivered by long-lived isotopes of uranium, thorium and potassium. The presence of rubidium and cosmic radiation generally play a lesser but contributory roll, and the total radiation dose delivered to the TL phosphor is modified by the presence of water. The period since deposition is therefore measured by determining the total amount of stored TL energy, the palaeodose (P), and the rate at which this energy is acquired, the annual radiation dose (ARD). TL dating may be applied to eolian, fluvial, coastal and in some cases, marine sediments. the technique is also successfully applied to volcanic materials and to a certain extent to archeological specimens

Application of thermoluminescence measurements to detect low dose gamma-irradiated table grapes

International Nuclear Information System (INIS)

Sillano, O.; Rubio, T.; Espinoza, J.; Roman, A.; Deza, A.

1994-01-01

A major factor hampering the introduction of ionizing radiation as an alternative quarantine treatment to chemical fumigation for fruit and vegetables is the lack of reliable, simple and inexpensive post-treatment methods to confirm this low dose irradiation treatment. Thermoluminescence (TL) measurements of the wind blown dust naturally adhering to the surface of table grapes, was surveyed. Two doses, 0.5 and 1.0 kGy, were studied, applied to the main Chilean table grape export varieties: Thompson Seedless and Flame Seedless. TL measurements were carried out over 78 days for Thompson Seedless and 62 days for Flame Seedless varieties, both stored at 1 ± 1 o C. TL response fading of dust samples stored at room temperature was also followed over 125days. The TL response values obtained from the irradiated samples exceeded at least 3 times the highest ones obtained from the unirradiated counterparts. The treatment, even for the lower γ-radiation dose applied, could be properly detected well above the shipping and marketing time for this Chilean export fruit (2-8 weeks). This method also has the advantage of using relatively inexpensive equipment. (author)

Thermoluminescence characteristics of Li2B4O7 single crystal dosimeters doped with Mn

International Nuclear Information System (INIS)

Ekdal, E.; Karalı, T.; Kelemen, A.; Ignatovych, M.; Holovey, V.; Harmansah, C.

2014-01-01

In this study, thermoluminescence (TL) characterization of newly developed Li 2 B 4 O 7 :Mn single crystal phosphor is reported. It is a very attractive material in personal dosimetry because of its near tissue equivalency (Z eff =7.25). The crystal was grown by the Czochralski method from high purity compounds. Glow curve, dose response, and fading and reproducibility properties of this material were investigated. Its TL glow curve showed two well separated peaks at about 105 and 220 °C with a heating rate of 2 °C s −1 . The main peak at 220 °C has a linear dose response of up to 60 Gy. The thermal fading ratio of the material is about 8% for the main peak in 10 days. The results showed that there is no significant variation of TL responses for 15 sequential measurements. Apart from the dosimetric properties above, the TL kinetic parameters of the main peak at 220 °C of Li 2 B 4 O 7 :Mn single crystal phosphor were also calculated using the various heating rates method. Activation energy and frequency factor were found as 1.21 eV and 3.75×10 11 s −1 , respectively. - Highlights: • Li 2 B 4 O 7 :Mn single crystal was investigated in terms of TL characteristics. • The material shows highly satisfactory dosimetric properties. • Various heating rates method was used for determining the kinetic parameter

Protocols for Thermoluminescence and Optically Stimulated Luminescence Research at DOSAR

International Nuclear Information System (INIS)

Bernal, SM

2004-01-01

The Life Sciences Division (LSD) of Oak Ridge National Laboratory (ORNL) has a long record of radiation dosimetry research at the Dosimetry Applications Research (DOSAR) facility complex. These facilities have been used by a broad segment of the research community to perform a variety of experiments in areas including, but not limited to, radiobiology, radiation dosimeter and instrumentation development and calibration, and materials testing in a variety of radiation environments. Collaborations with the University of Tennessee-Knoxville (UTK) have also led to important contributions in the area of archaeometry, particularly as it relates to the use of radiation dosimetry to date archaeological artifacts. This manual is to serve as the primary instruction and operation manual for dosimetric and archaeometric research at DOSAR involving thermoluminescence (TL) and optically stimulated luminescence (OSL). Its purpose is to (1) provide protocols for common practices associated with the research, (2) outline the relevant organizational structure, (3) identify the Quality Assurance plan, and (4) describe all the procedures, operations, and responsibilities for safe and proper operation of associated equipment. Each person who performs research at DOSAR using TL/OSL equipment is required to read the latest revision of this manual and be familiar with its contents, and to sign and date the manual's master copy indicating that the manual has been read and understood. The TL/OSL Experimenter is also required to sign the manual after each revision to signify that the changes are understood. Each individual is responsible for completely understanding the proper operation of the TL/OSL equipment used and for following the guidance contained within this manual. The instructions, protocols, and operating procedures in this manual do not replace, supersede, or alter the hazard mitigation controls identified in the Research Safety Summary (''Thermoluminescence/Optically Stimulated

Synthesis of CaF{sub 2}: dy for thermoluminescent dosimetry

Energy Technology Data Exchange (ETDEWEB)

Yamato, M.E.P.; Vasconcelos, D.A.A. de; Asfora, V.K.; Khoury, H.J.; Santos, R.A.; Barros, V.S.M., E-mail: mepyamato@gmail.com [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Departamento de Energia Nuclear

2015-07-01

Calcium Fluoride doped with dysprosium is a known thermoluminescent material for applications that require highly sensitive dosimeters. Research in novel methods such as Combustion Synthesis (CS) has been ongoing for several years at the University of Pernambuco. The method uses the heat of the oxi-redox reaction a between nitrate and a fuel. This work presents results of CaF{sub 2}:Dy produced by combustion synthesis under different fabrication conditions. Samples were prepared by mixing stoichiometric amounts of calcium nitrate, urea and ammonium nitrate in a beaker under vigorous stirring. The resulting gel was transferred to a pre-heated muffle furnace were the combustion reaction occurred after a few minutes. For comparison, a variation of the production method with the same amounts of nitrate, ammonium fluoride and dopant, but without using the fuel was prepared. For both methods the resulting powder was pelleted and irradiated with Co-60 gamma radiation. The reproducibility and sensitivity for gamma dose irradiation was tested and results showed that optimum TL sample reproducibility was without the urea as fuel. Samples were then prepared with 0.05, 0.10, 0.15 and 0.20 mol% Dy concentration. The highest TL sensitivity was found for samples with 0.15 mol% Dy and sintered at 400 deg C for 3.5 h in air. The TL emission spectra, obtained using a Hammamatsu optical spectrometer, was comparable with commercial CaF{sub 2}:Dy. Thermoluminescence was measured in a Harshaw-Bicron 3500 TL Reader. The glow curve showed stable dosimetric peaks at around 200, 235 and 300 deg C were a linear dose response curve was obtained for the range 100 mGy to 1000 mGy. (author)

Thermoluminescence spectra of natural CaF2 irradiated by 10MeV electrons

International Nuclear Information System (INIS)

Manrique, J.; Angulo, S.; Pardo, M.P.; Gastesi, R.; De la Cruz, A.; Perez, A.

2006-01-01

The spectra of thermoluminescence from natural and electron-irradiated fluorite in the 350-800nm spectral range were studied between room temperature and 500 o C. The sample came from Asturias (Spain) and was analyzed by X-ray diffractometry and inductively coupled plasma-mass spectrometry. Glow peaks appeared at 115, 205 and 310 o C. Main emissions occurred at 475, 575, 650 and 745nm, attributed to the Dy +3 ion and, at 410nm, from electron-hole recombination. The fractional glow technique and the general order model were employed to study the emission at 575nm in detail. The results showed that the 115 and 205 o C glow peaks originate at traps with activation energies of 1.6 and 1.9eV, respectively, on the kinetic order of 1.5 and 1.3 and frequency factors of 1.7x10 19 and 2.7x10 19 s -1 , respectively. Spectrally resolved fading produced by storage was observed, and we concluded that the emission was due to large defect complexes. The dosimetric study showed that there was saturation at doses higher than 2kGy

Study of Syrian archaeological pottery by the combined application of thermoluminescence (TL) dating, X-ray fluorescence analysis and statistical multivariate analysis

International Nuclear Information System (INIS)

Bakraji, E.H.

2012-01-01

X-ray fluorescence method and the technique of thermoluminescence (TL) dating have been utilized for the study of archaeological pottery fragment samples, fairly representative of Romanian period between 1 st century B.C. and 4th century A.D, from Judaidet Yabous site, which is located north-west of Damascus city, Syria. Four samples were chosen randomly among the forty six samples for dating using thermoluminescence technique and the results were in good agreement with the date assigned by archaeologists. The samples were irradiated for 1000 s live time twice, first using a Mo X-ray Tube and second using a 109 Cd radioactive source. Fifteen elements (K, Ca, Ti, Mn, Fe, Ni, Cu, Zn, Ga, Rb, Sr, Y, Zr, Nb, and Pb) were determined. The elemental concentrations have been processed using two multivariate statistical methods. The purpose of the study was to characterize by means of elements contents the pottery paste from Judaidet Yabous archaeological site and providing new data to the Syrian databases for future studies. From an archaeological point of view the results indicated that most of the potteries, were locally produced. (author)

Evaluation of glasses containing cadmium for high dose dosimetry by the thermoluminescence technique

Energy Technology Data Exchange (ETDEWEB)

Carvalho, Gabriel Soares Marchiori de; Ferreira, Pamela Zati; Cunha, Diego Merigue da; Dantas, Noelio Oliveira; Silva, Anielle C.A.; Perini, Ana Paula; Neves, Lucio Pereira, E-mail: lucio.neves@ufu.br [Universidade Federal de Uberlandia (INFIS/UFU), MG (Brazil). Instituto de Fisica; Caldas, Linda V.E. [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Sao Paulo, SP (Brazil); Carrera, Betzabel Noemi Silva; Watanabe, Shigueo [Universidade de Sao Paulo (IF/USP), SP (Brazil). Instituto de Fisica

2016-07-01

New glass matrices were evaluated for high dose dosimetry by the thermoluminescence technique. Their nominal composition are 20Li{sub 2}CO{sub 3}.10Al{sub 2}O{sub 3}.15CdO.55B{sub 2}O{sub 3} and 20Li{sub 2}CO{sub 3}.10Al{sub 2}O{sub 3}.20CdO.50B{sub 2}O{sub 3} (mol%). The glass matrices were irradiated with different doses: 50, 100, 200, 500, 700 and 900 Gy, and the thermoluminescence emission curves were obtained for each of these values. The results show a great potential of using these matrices in high dose dosimetry. (author)

Study of a new glass matrix by thermoluminescent technique for high-dose dosimetry

Energy Technology Data Exchange (ETDEWEB)

Ferreira, Pamela Z.; Carvalho, Gabriel S. Marchiori de; Cunha, Diego M. da; Dantas, Noelio O.; Silva, Anielle C.A.; Neves, Lucio P.; Perini, Ana P., E-mail: anapaula.perini@ufu.br [Universidade Federal de Uberlandia (UFU), MG (Brazil). Instituto de Fisica; Linda, V.E. Caldas [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Carrera, Betzabel N.S.; Watanabe, Shigueo [Universidade de Sao Paulo (IF/USP), Sao Paulo, SP (Brazil). Instituto de Fisica

2016-07-01

The thermoluminescence technique is widely used for both personal and for high-dose dosimetry. In this work, the thermoluminescence technique was utilized to study a new glass matrix, with nominal composition of 20Li{sub 2}CO{sub 3}.10Al{sub 2}O{sub 3}.30BaO.40B{sub 2}O{sub 3} (mol%), irradiated with different doses in a {sup 60}Co source. The glow curves and the dose-response curve were obtained for radiation doses of 10, 50, 100, 200 e 700 Gy. The results showed that this new glass matrix has potential use in high-dose dosimetry. (author)

Oxidation/reduction effects on sapphire thermoluminescent detectors

International Nuclear Information System (INIS)

Molnar, G.; Borossay, J.; Suevegh, K.; Vertes, A.

1998-01-01

Complete text of publication follows. The thermoluminescence (TL) and thermally stimulated exoemission (TSEE) properties of Al 2 O 3 has been extensively studied during the past 40 years. It has been suggested as a dosemeter for both ultraviolet light and ionising radiation. Nevertheless the connection between the structure (point defects) of alumina and thermally stimulated relaxation processes has not yet been clearly explained. In this work α-Al 2 O 3 single crystal samples were studied in order to determine the mechanism of electron-hole processes of thermoluminescence and thermally stimulated exoelectron emission peaks. Single crystals prepared in highly reducing conditions were treated in different atmospheres (reducing/oxidising) and their optical absorption (after isochronous annealing), fluorescence, positron-annihilation and TL properties were investigated. Changes of optical absorption and positron annihilation spectra of oxidised samples suggest that Schottky-type defect formation occurred - the concentration of Al-vacancies increased while that of O-vacancies decreased. Also we observed the oxidation of Ti 3+ to Ti 4+ . The reduction of an oxidised sample led to the diminution of Al-vacancy concentration while that of O-vacancies has not been changed. This suggest a Frenkel-type cationic defect. We also tried to correlate these changes to changes of TL glow curves and to explain the origin of some TL peaks

Synthesis, characteristics and thermoluminescent dosimetry features of γ-irradiated Ce doped CaF2 nanophosphor.

Science.gov (United States)

Zahedifar, M; Sadeghi, E; Mozdianfard, M R; Habibi, E

2013-08-01

Nanoparticles of cerium doped calcium fluoride (CaF2:Ce) were synthesized for the first time using the hydrothermal method. The formation of nanostructures was confirmed by X-ray diffraction (XRD) patterns, indicating cubic lattice structure for the particles produced. Their shape and size were observed by scanning electron microscopy (SEM). Thermoluminescence characteristics were studied by having the samples irradiated by gamma rays of (60)Co source. The optimum thermal treatment of 400 °C for 30 min was found for the produced nanoparticles. The Tm-Tstop and computerized glow curve deconvolution (CGCD) methods, used to determine the number of component glow peaks and kinetic parameters, indicated seven overlapping glow peaks on the TL glow curve at approximately 394, 411, 425, 445, 556, 594 and 632 K. A linear dose response of up to 2000 Gy, was observed for the prepared nanoparticles. Maximum TL sensitivity was found at 0.4 mol% of Ce impurity. Other TL dosimetry features, including reusability and fading, were also presented and discussed. Copyright © 2013 Elsevier Ltd. All rights reserved.

Ultraviolet radiation monitoring in makkah city, Saudi Arabia, using thermoluminescence material CaF2:Tm

International Nuclear Information System (INIS)

Al-Ghorabie, F.H.; Natto, S.S.; AL-Lehyani, S.A.

2005-01-01

The aim of the present study is to explore the possibility of using Ca F2:Tm thermoluminescence material for measuring and monitoring of solar UV R in Makkah City, Saudi Arabia. Several laboratory experiments, prior to the field measurements, were performed included study of the effects of ultraviolet wavelengths on the response of the phosphor, study of the effect of increasing ultraviolet radiation dose on the intensity of thermoluminescence and study the effect of time factor on the thermoluminescence fading of Ca F 2 :Tm. The phosphor was then exposed directly for one hour to sunlight radiation on a daily basis for 90 days in an open field inside Umm Al-Qura university campus. The field measurements were performed during the months of June, July and August 2003 at 1:00 p.m. The laboratory and field results of this study showed that Ca F 2 :Tm can be used as a suitable dosimeter for solar UV R

Methods for implementation of in vivo dosimetry (entrance dose) using thermoluminescent dosimeters during radiotherapy treatment with photon beam

International Nuclear Information System (INIS)

Barsanelli, Cristiane

2006-01-01

Selection, calibration procedure to convert TLD signal into absorbed dose and physical characteristics at the thermoluminescent dosimeters, as well as the determination of correction factors and the methodology to determine expected entrance dose, are described in this work. Practical aspects and the utility of entrance dose measures with thermoluminescent dosimeters were investigated, as well as the exactness and the reproducibility of the daily dose release. The entrance dose measures were performed in five patients with diagnosis of breast cancer treated with a 6 MV photon beam. The measured dose and the expected dose values agreed in ± 5%, due to excellent treatment equipment stability, to automatic verification system and the good exactness in the daily treatment adjustment. Good precision can be achieved when the correction factors for each parameter of influence in the dosimeter response are carefully determined and applied to convert the thermoluminescent signal into absorbed dose. The study demonstrates the viability of thermoluminescent dosimeters use for in vivo dosimetry and its utility as part of a quality assurance program in a radiation therapy service. (author)

The thermoluminescent curve as parameter to compare archaeological ceramics; La curva termoluminiscente como parametro para comparar ceramica arqueologica

Energy Technology Data Exchange (ETDEWEB)

Dominguez R, I.R.; Ramirez C, G.A. [Centro INAH Estado de Mexico. Morelos Ote. 502, Col. San Sebastian, 50090 Toluca, Estado de Mexico (Mexico); Gonzalez M, P.R.; Mendoza A, D. [lNIN, Carr. Mexico-Toluca S/N, La Marquesa, 52750 Ocoyoacac, Estado de Mexico (Mexico); Martinez C, G. [Coordinacion Nacional de Conservacion del Patrimonio Cultural, INAH, Mexico D.F. (Mexico)

2006-07-01

Most mineral materials, including the constituents of pottery, have the property of thermoluminescence (TL), where part of the energy from radioactive decay in the mineral is stored and later released as light upon strong heating. The intensity of emitted light as a function of temperature is the thermoluminescence glow curve. However, it is well-know the thermoluminescence glow curve form depends of several factors associates with the incident radiation and type of materials. Between the factors associated with the materials, it can be mentioned the quantity and type of crystalline phases, and quantity and type of impurities that they could be present in the material. That is to say, materials with different physicochemical characteristics will produce different thermoluminescence glow curve, although, they have been irradiated under the same conditions. In accordance with the above mentioned, it is possible to identified differences between pre hispanic ceramic belonging to a same site and other sites. In this work a discussion about advantages and disadvantages is presented. Some specific examples in ceramic artifacts belonging to the Matlatzinca and Teotihuacan cultures are included. (Author)

Investigations on thermoluminescent dosimetry (TLD) with doped alumina ceramics

International Nuclear Information System (INIS)

Janas, R.; Huebner, K.

1976-01-01

Alumina ceramics doped and burned under various conditions have been investigated with regard to their suitability for thermoluminescent dosimetry. The production of ceramics is described. The properties essential for dosimetric purposes, such as glow curve, energy dose characteristics, fading, recoverability, lower detection limit and energy dependence, are indicated. The advantages and disadvantages of alumina ceramics are compared. (author)

Thermically stimulated exoelectronic emissions and thermoluminescence of MgO

International Nuclear Information System (INIS)

Chubaci, J.F.D.

1987-01-01

In this work, studies were performed on the following topics: i) thermically stimulated exoelectronic emission (TSEE) in pure MgO single crystals ion implanted, submitted to thermal treatment with fast on slow cooling and water adsorption; ii) ultraviolet light effect on TSEE; iii) thermoluminescent emission; iv) crystallization of FeCoB amorphous alloys. (A.C.A.S.) [pt

Development of a highly sensitive lithium fluoride thermoluminescence dosimeter

International Nuclear Information System (INIS)

Moraes da Silva, Teresinha de; Campos, Leticia Lucente

1995-01-01

In recent times, LiF: Mg, Cu, P thermoluminescent phosphor has been increasingly in use for radiation monitoring due its high sensitivity and ease of preparation. The Dosimetric Materials Production Laboratory of IPEN, (Nuclear Energy Institute) has developed a simple method to obtain high sensitivity LiF. The preparation method is described. (author). 4 refs., 1 fig., 1 tab

A study of the thermoluminescent properties of CVD diamond detectors

International Nuclear Information System (INIS)

Marczewska, B.; Bilski, P.; Olko, P.; Rebisz, M.; Nesladek, M.; Waligorski, M.P.R.

2002-01-01

A batch of 20 diamond detectors obtained by the chemical vapour deposition (CVD) method at the Institute for Materials Research at the Limburg University, Belgium, was investigated with respect to their thermoluminescent (TL) properties. The investigated detectors demonstrate TL sensitivity similar to that of the standard LiF:Mg, Ti (MTS) thermoluminescent detectors, lack of fading after two weeks from irradiation and apparent linearity of dose response. In spite of the persistent fluctuation of individual detector sensitivity observed in this batch, a new annealing procedure improved the stability of the TL signal. It has been concluded that 1 h annealing at 350 C assures the highest reproducibility for this set of detectors. A 30% discrepancy of the value of the TL signal between individual detectors from the batch may be caused by non-uniform distribution of dopants in the volume of the CVD diamond. A prototype of a planar TL reader equipped with a CCD camera was employed in this investigation. (Abstract Copyright [2002], Wiley Periodicals, Inc.)

Development of a nano structured system based on zirconia and Co nanoparticles for thermoluminescent applications: sensor of gamma and UV radiation; Desarrollo de un sistema nanoestructurado a base de zirconia y nanoparticulas de Co para aplicaciones termoluminiscentes: sensor de radiacion gamma y UV

Energy Technology Data Exchange (ETDEWEB)

Villa S, G.

2014-07-01

Powders of zirconium IV oxide as well as systems composed of zirconia nano crystals and cobalt nanoparticles (ZrO{sub 2}:NPCo) with dimensions of nanometers were synthesized by the sol-gel method. Zirconia and ZrO{sub 2}:NPCo systems have crystalline structure tetragonal or monoclinic is the heat treatment was to 500 and 1000 degrees Celsius respectively. The characterization of the synthesized materials consisted of a morphological and structural analysis, the information obtained was correlated to its thermoluminescent response induced by gamma and ultraviolet radiation. Thermoluminescent behavior was analyzed on different concentrations of cobalt nanoparticles incorporated during the synthesis process of the zirconium oxide. The monoclinic structure has the highest sensitivity thermoluminescent induced by ultraviolet and gamma radiation. Moreover, the thermoluminescence intensity decreased considerably in ZrO{sub 2}:NPCo systems and was induced the growth of a glow peak at 280 degrees Celsius. In most of the materials analyzed the relation of the thermoluminescence intensity depending the time of irradiation with ultraviolet light showed the saturation of the traps in the material after 60 s of irradiation. Using gamma radiation is observed a behavior linear in the applied dose range between 0.25 Gy and 450 Gy. The growth of a glow peak at 280 degrees Celsius is the most important change in the thermoluminescence characteristics of zirconia. The ZrO{sub 2}:NPCo systems can be used in the development of thermoluminescent dosimeters for detecting gamma radiation fields mainly. (Author)

On the phototransferred thermoluminescence in MgB4O7:Dy

International Nuclear Information System (INIS)

Richmond, R.G.

1987-01-01

On exposure to ionizing radiations, the normal traps in MgB 4 0 7 :Dy can be emptied by the readout process only or by annealing at suitable temperatures, leaving the deep traps still intact. Subsequently, it is possible to repopulate the dosimetric peak by illuminating with u.v. light. Charge carriers released from the traps during the second readout give rise to a thermoluminescent output proportional to the ionizing radiation exposure and the u.v. radiant energy. This is called phototransferred thermoluminescence (PTTL). The PTTL method can be utilized for the reassessment of the initial γ-ray exposure. This paper presents the measurements of the intrinsic response of the commercially available MgB 4 0 7 :Dy to u.v. radiation, with a demonstration of its use for γ-ray dose re-estimation using the PTTL technique. (author)

Authenticity test in ceramics and archaeological figures by thermoluminescence; Prueba de Autenticidad en ceramicas y figuras arqueologicas por termoluminiscencia

Energy Technology Data Exchange (ETDEWEB)

Ramirez L, A.; Schaaf, P. [Laboratorio de Termoluminiscencia, Instituto de Geofisica-UNAM (Mexico); Filloy, L. [Museo Nacional de Antropologia e Historia, Ciudad de Mexico (Mexico)

1999-07-01

At present exists quite a lot of false archaeological pieces which provokes doubts about the legitimacy of the pieces. In this work it is presented the Authenticity test by Thermoluminescence realized at the urn of the goddess 13 serpent of the zapotec culture of Oaxaca which is exposed in Mexico City. The original piece contains crystalline structures which present hardly the thermoluminescence phenomena by the presence of {sup 238} U, {sup 232} Th, and {sup 40} K getting with this the form and intensity of the natural thermoluminescence curve of an archaeological piece which shows a Tl peak and allows to know so if it was made recently or not. (Author)

Mechanism, kinetics and application studies on enhanced activated sludge by interior microelectrolysis.

Science.gov (United States)

Yang, Xiaoyi; Xue, Yu; Wang, Wenna

2009-01-01

Enhanced activated sludge by interior microelectrolysis (EAIM) was studied to treat textile wastewater, kinetics, mechanism and application of which were also discussed in comparison with traditional activated sludge and interior microelectrolysis, respectively. The results of kinetics study indicated three different processes all followed first-order kinetics well. In EAIM, three impact factors take effects on COD removal, which are flocculation, activated sludge and electrophoresis and redox. In terms of assumption of no interaction among three COD removal mechanisms, 49.6% of the total COD removal is ascribed to flocculation, 30.1% to activated sludge and 20.3% to electrophoresis and redox. EAIM showed its advantages in COD removal efficiency, extensive adaptability to complex composition and wide range of pH. EAIM-aerobic process provided an efficient and economic performance for dealing with textile wastewater.

CSP-based chemical kinetics mechanisms simplification strategy for non-premixed combustion: An application to hybrid rocket propulsion

KAUST Repository

Ciottoli, Pietro P.; Malpica Galassi, Riccardo; Lapenna, Pasquale E.; Leccese, G.; Bianchi, D.; Nasuti, F.; Creta, F.; Valorani, M.

2017-01-01

A set of simplified chemical kinetics mechanisms for hybrid rocket applications using gaseous oxygen (GOX) and hydroxyl-terminated polybutadiene (HTPB) is proposed. The starting point is a 561-species, 2538-reactions, detailed chemical kinetics

NRC [Nuclear Regulatory Commission] TLD [thermoluminescent dosimeter] direct radiation monitoring network

International Nuclear Information System (INIS)

Struckmeyer, R.; McNamara, N.

1989-09-01

This report provides the status and results of the NRC Thermoluminescent Dosimeter (TLD) Direct Radiation Monitoring Network. It presents the radiation levels measured in the vicinity of NRC licensed facility sites throughout the country for the second quarter of 1989

Thermoluminescence as a criterium in the acquisition of ceramic art objects

International Nuclear Information System (INIS)

Erlach, R.; Pichler, B.

1985-01-01

Thermoluminescence is a measure for the external archeological dose received and can be used for age estimation. Examples are given of Egyptian objects where the age is known independently and thereby the accuracy of the method can be evaluated. (G.Q.)

Utilization of thermoluminescent dosemeters in radiation field studies for different materials

International Nuclear Information System (INIS)

Carron, W.; Guilardi Neto, T.

1987-01-01

The dose conversion factor of lithium fluoride thermoluminescent for the follows materials: water, wood and soil, the dose curve surveying in function of depth and the regression equations that better adapt to the dose curves were calculated. (C.G.C.) [pt

Surrogate models and optimal design of experiments for chemical kinetics applications

KAUST Repository

Bisetti, Fabrizio

2015-01-07

Kinetic models for reactive flow applications comprise hundreds of reactions describing the complex interaction among many chemical species. The detailed knowledge of the reaction parameters is a key component of the design cycle of next-generation combustion devices, which aim at improving conversion efficiency and reducing pollutant emissions. Shock tubes are a laboratory scale experimental configuration, which is widely used for the study of reaction rate parameters. Important uncertainties exist in the values of the thousands of parameters included in the most advanced kinetic models. This talk discusses the application of uncertainty quantification (UQ) methods to the analysis of shock tube data as well as the design of shock tube experiments. Attention is focused on a spectral framework in which uncertain inputs are parameterized in terms of canonical random variables, and quantities of interest (QoIs) are expressed in terms of a mean-square convergent series of orthogonal polynomials acting on these variables. We outline the implementation of a recent spectral collocation approach for determining the unknown coefficients of the expansion, namely using a sparse, adaptive pseudo-spectral construction that enables us to obtain surrogates for the QoIs accurately and efficiently. We first discuss the utility of the resulting expressions in quantifying the sensitivity of QoIs to uncertain inputs, and in the Bayesian inference key physical parameters from experimental measurements. We then discuss the application of these techniques to the analysis of shock-tube data and the optimal design of shock-tube experiments for two key reactions in combustion kinetics: the chain-brancing reaction H + O2 ←→ OH + O and the reaction of Furans with the hydroxyl radical OH.

Thermoluminescent characteristics of LiF:Mg, Cu, P and CaSO_4:Dy for low dose measurement

International Nuclear Information System (INIS)

Del Sol Fernández, S.; García-Salcedo, R.; Mendoza, J. Guzmán; Sánchez-Guzmán, D.; Rodríguez, G. Ramírez; Gaona, E.; Montalvo, T. Rivera

2016-01-01

Thermoluminescence (TL) characteristics for LiF:Mg, Cu, P, and CaSO_4:Dy under the homogeneous field of X-ray beams of diagnostic irradiation and its verification using thermoluminescence dosimetry are presented. The irradiation were performed utilizing a conventional X-ray equipment installed at the Hospital Juárez Norte of México. Different thermoluminescence characteristics of two material were studied, such as batch homogeneity, glow curve, linearity, detection threshold, reproducibility, relative sensitivity and fading. Materials were calibrated in terms of absorbed dose to the standard calibration distance and they were positioned in a generic phantom. The dose analysis, verification and comparison with the measurements obtained by the TLD-100 were performed. Results indicate that the dosimetric peak appears at 202 °C and 277.5 °C for LiF:Mg, Cu, P and CaSO_4:Dy, respectively. TL response as a function of X-ray dose showed a linearity behavior in the very low dose range for all materials. However, the TLD-100 is not accurate for measurements below 4 mGy. CaSO_4:Dy is 80% more sensitive than TLD-100 and it show the lowest detection threshold, whereas LiF:Mg, Cu, P is 60% more sensitive than TLD-100. All materials showed very good repeatability. Fading for a period of one month at room temperature showed low fading LiF:Mg, Cu, P, medium and high for TLD-100 and CaSO_4:Dy. The results suggest that CaSO_4:Dy and LiF:Mg, Cu, P are suitable for measurements at low doses used in radiodiagnostic. - Highlights: • Several dosimetric characteristics were evaluated. • TL dose response to very low dose X-rays was studied. • The applications proposed for each material may be useful for diagnostic radiology dosimetry.

In vivo dosimetry using thermoluminescent detector in cancer therapy of head and neck

International Nuclear Information System (INIS)

Viegas, Claudio C.B.; Batista, D.V.; Campos, A.M.; Lopes, R.T.

2002-01-01

The viability and implementation of a routine in vivo dosimetry, using thermoluminescent dosemeters (TLD), at the radiotherapy section of the National Institute of Cancer in Brazil, in the case of head and neck treatment is shown. In order to reach that aim, the characteristics of the response of the LiF:Mg;Ti (TLD-100) thermoluminescent detectors in powder form were determined. The performed of this detector for in vivo dosimetry was testes using an RANDO Alderson anthropomorphic phantom and, once their adequability proved for the kind of measurements proposed , it was used for dose assessment in the case of tumour treatments in the head and neck regions, for Cobalt-60 irradiations. (author)

Thermoluminescence glow curve of CaZrO3 phosphor doped with Eu3+

International Nuclear Information System (INIS)

Tiwari, Neha; Kuraria, R.K.; Kuraria, S.R.

2014-01-01

Behaviour displayed by thermoluminescence analysis of Eu 3+ doped CaZrO 3 phosphor prepared by combustion synthesis technique. The sample was synthesized by combustion method because it is less time taking method as well as low temperature synthesis. For the thermoluminescence study the prepared sample irradiated by UV lamp the wavelength is 254 nm. Every time 2 mg of sample used for TL record at fixed heating rate 5℃ s -1 , sample shows well resolved higher temperature peak at 273℃. The high temperature peak shows more stability and less fading in prepared phosphor which is suitable for TL dosimetry. Also the variation with UV dose (5 to 30 min) shows sublinear response with dose

Thermoluminescent dosimetry for LDEF experiment M0006

International Nuclear Information System (INIS)

Chang, J.Y.; Giangano, D.; Kantorcik, T.; Stauber, M.; Snead, L.

1992-01-01

Experiment M0006 on the Long Duration Exposure Facility had as its objective the investigation of space radiation effects on various electronic and optical components, as well as on seed germination. The Grumman Corporate Research Center provided the radiation dosimetric measurements for M0006, comprising the preparation of thermoluminescent dosimeters (TLD) and the subsequent measurement and analysis of flight exposed and control samples. In addition, various laboratory exposures of TLD's with gamma rays and protons were performed to obtain a better understanding of the flight exposures

Principles of chemical kinetics

CERN Document Server

House, James E

2007-01-01

James House's revised Principles of Chemical Kinetics provides a clear and logical description of chemical kinetics in a manner unlike any other book of its kind. Clearly written with detailed derivations, the text allows students to move rapidly from theoretical concepts of rates of reaction to concrete applications. Unlike other texts, House presents a balanced treatment of kinetic reactions in gas, solution, and solid states. The entire text has been revised and includes many new sections and an additional chapter on applications of kinetics. The topics covered include quantitative rela

An optical fibre-type silicate glass thermoluminescent detector

International Nuclear Information System (INIS)

Zheng Zheng; Dai Honggui; Hu Shangze; Liu Jian; Fang Jie

1991-01-01

A description of dosimetric properties and the preparation method of an optical fibre-type silicate glass thermoluminescent detector (TLD) is presented. Results showed that this new phosphor is a good one which could be used as a routine dosimeter in the range 10 -1 -10 3 Gy. The preparation method is a new one which differs greatly from all previous ones. Furthermore this kind of detector is small and of low weight. (orig.)

Thermoluminescent dosimetry of ionizing radiations using ZrO2 prepared at low temperatures

International Nuclear Information System (INIS)

Rivera M, T.; Diaz G, J.A.I.; Olvera T, L.; Azorin N, J.; Barrera S, M.; Soto E, A.M.

2005-01-01

The thermoluminescent dosimetry (TLD) it is a versatile tool for an evaluation of dose of ionizing radiation. A great variety of ceramic materials and their different physical forms allow a determination of the ionizing radiation in a wide dose interval. In this work the results of studying those thermoluminescent characteristics (TL) of the zirconium oxide obtained by means of the sol-gel technique to low temperatures are presented. To these temperatures the material was obtained in its amorphous state (ZrO 2 -a). The structural characteristics of ZrO 2 -a they were obtained by means of X-ray diffraction. The TL characteristics studied were: TL curve, reproducibility of the TL signal and the fading of the information. The powders of ZrO 2 -a, previously irradiated with beta particles of 90 Sr/ 90 Y, they presented a thermoluminescent curve with two peaks at 150 and 260 C. The fading of the information of the one ZrO 2 -a it was of 20% during the first two hours starting from this time there was one lost of information of 5% to the finish of the 30 days. The reproducibility of the information was of ± 2.5% in standard deviation. (Author)

Modelling the optical bleaching of the thermoluminescence of K2YF5:Pr3+

International Nuclear Information System (INIS)

Marcazzó, J.; Santiago, M.; Khaidukov, N.; Caselli, E.

2012-01-01

Optical bleaching of the thermoluminescence (TL) curve of K 2 YF 5 :Pr 3+ has been observed after optically stimulated luminescence (OSL) readout of pre-irradiated crystals. The traps being responsible for the TL signal are not emptied completely by the optical stimulation. Furthermore, if the illumination time is increased a constant intensity level of the residual TL glow curve is eventually achieved. On the other hand, if the low temperature peak of the glow curve is thermally cleaned, no subsequent OSL is measured. This behavior has been successfully explained by assuming that part of the electrons in the trap being responsible for the low temperature glow peak of K 2 YF 5 :Pr 3+ recombine with holes via localized transitions during optical stimulation. During TL all trapped electrons recombine via delocalized transitions. Simulations have been carried out in order to demonstrate the feasibility of the model. - Highlights: ► The optical bleaching of the thermoluminescence of K2YF5:Pr 3+ has been studied. ► A model accounting for the optical bleaching has been put forward. ► Thermoluminescence occurs via delocalized transitions. ► Localized transitions occur during optical stimulation.

Thermally stimulated conductivity and thermoluminescence from Al2O3 : C

DEFF Research Database (Denmark)

Agersnap Larsen, N.; Bøtter-Jensen, L.; McKeever, S.W.S.

1999-01-01

Simultaneous measurements of thermoluminescence (TL) and thermally stimulated conductivity (TSC) are reported on single-crystal dosimetry-quality Al2O3:C following gamma irradiation at room temperature. Analysis of the data reveals a superposition of several first-order TL and TSC peaks caused...

Thermoluminescence dating of some Hungarian medieval churches

International Nuclear Information System (INIS)

Kasa, I.; Bajnoczy, G.

1984-01-01

Thermoluminescence dating of three Hungarian historic churches was performed using the quarz inclusion technique and sup(60)Co gamma irradiation. Quarz grains obtained from the bricks were irradiated and the radiation doses were measured by CaSOsub(4):Dy TL dosemeters. Glow curves of irradiated and non-irradiated samples were also measured. From the results it was concluded that the ages of two churches were 10 and 30 percent less, respectively, than the ages estimated earlier. The age of the third church proved to be correct. (R.P.)

The influence of radiation-induced defects on thermoluminescence and optically stimulated luminescence of α-Al_2O_3:C

International Nuclear Information System (INIS)

Nyirenda, A.N.; Chithambo, M.L.

2017-01-01

It is known that when α-Al_2O_3:C is exposed to excessive amounts of ionising radiation, defects are induced within its matrix. We report the influence of radiation-induced defects on the thermoluminescence (TL) and optically stimulated luminescence (OSL) measured from α-Al_2O_3:C after irradiation to 1000 Gy. These radiation-induced defects are thermally unstable in the region 450–650 °C and result in TL peaks in this range when the TL is measured at 1 °C/s. Heating a sample to 700 °C obliterates the radiation-induced defects, that is, the TL peaks corresponding to the radiation induced defects are no longer observed in the subsequent TL measurements when moderate irradiation doses below 10 Gy are used. The charge traps associated with these radiation-induced defects are more stable than the dosimetric trap when the sample is exposed to either sunlight or 470-nm blue light from LEDs. TL glow curves measured following the defect-inducing irradiation produce a dosimetric peak that is broader and positioned at a higher temperature than observed in glow curves obtained before the heavy irradiation. In addition, sample sensitization/desensitization occurs due to the presence of these radiation-induced defects. Furthermore, both the activation energy and the kinetic order of the dosimetric peak evaluated when the radiation-induced defects are present in the sample are significantly lower in value than those obtained when these defects are absent. The radiation-induced defects also affect the shape and total light sum of the OSL signal as well as the position and width of the resultant residual phototransferred thermoluminescence main peak.

Measurement of the dose by dispersed radiation in a lineal accelerator using thermoluminescent dosimeters of CaSO4:Dy

International Nuclear Information System (INIS)

Chavez C, N.; Torijano, E.; Azorin, J.; Herrera, A.

2014-08-01

The thermoluminescence (Tl) is based on the principle of the luminescent in a material when is heated below their incandescence temperature. Is a technique very used in dosimetry that is based on the property that have most of the crystalline materials regarding the storage of the energy that they absorb when are exposed to the ionizing radiations. When this material has been irradiated previously, the radioactive energy that contains is liberated in form of light. In general, the principles that govern the thermoluminescence are in essence the same of those responsible for all the luminescent processes and, this way, the thermoluminescence is one of the processes that are part of the luminescence phenomenon. For this work, the dispersed radiation was measured in the therapy area of the lineal accelerator of medical use type Elekta, using thermoluminescent dosimeters of CaSO 4 :Dy + Ptfe developed and elaborated in the Universidad Autonoma Metropolitana, Unidad Iztapalapa. With the dosimeters already characterized and calibrated, we proceeded to measure the dispersed radiation being a patient in treatment. The results showed values for the dispersed radiation the order of a third of the dose received by the patient on the treatment table at 30 cm of the direct beam and the order of a hundredth in the control area (4 m of the direct beam, approximately). The conclusion is that the thermoluminescent dosimeters of CaSO 4 : Dy + Ptfe are appropriate to measure dispersed radiation dose in radiotherapy. (author)

Quality assurance package for routine thermoluminescence dosimetry program

International Nuclear Information System (INIS)

Tawil, R.A.; Bencke, G.; Moscovitch, M.

1988-01-01

The Quality Assurance Package presented here specifies a set of reader-related hardware diagnostics and calibration procedures and automatically maintains audit trails of generated and derived thermoluminescence data. It specifies acceptable performance criteria for the reader and dosimeter assemblies; tracks and controls Readout Cycle Temperature Profiles; and ensures that the acquired data is verified. The quality of the generated glow curves is tracked by the real-time application of Computerized Glow Curve Deconvolution to reference dosimeters that may be mixed with field dosimeters during readout sessions. This package is supported by a menu-driven software system using vertical auto-selection menus, lotus-style horizontal menus, data entry menus with automatic error checking, and pop-up windows. The menu system is supported by an extensive HELP file; data EDITING is password-protected, and a journal is maintained for each editing session as part of the audit trail. Files for the Raw Data and Derived Dose results are maintained and managed in seven databases. The paper provides an in-depth analysis of each of the procedures, specifies data validation criteria, and presents samples of the reports generated

Recent advances in thermoluminescence and photostimulated luminescence detection methods for irradiated foods

International Nuclear Information System (INIS)

Sanderson, D.C.W.; Carmichael, L.A.; Naylor, J.D.

1996-01-01

Thermoluminescence (TL) and photostimulated luminescence (PSL) are radiation-specific phenomena resulting from energy storage by trapped charge carriers in dielectric materials following irradiation. Releasing such stored energy by thermal or optical stimulation can result in detectable luminescence emission during the relaxation processes which follow. These approaches can be applied to inorganic components present either as inherent parts of foods or as adhering contaminants, and to bio-inorganic systems. The strengths of these techniques lies in their radiation-specificity, and the wide range of sample types which may by analysed. The Scottish Universities Research and Reactor Centre (SURRC) has been involved in the development and application of luminescence methods since 1986, during which time over 4000 analyses of more than 800 different food samples have been performed for research purposes, or in support of UK food labelling regulations. This paper discusses the present scope of luminescence techniques, and identifies areas where recent work has extended the range of applications, and indicates areas where further investigations may be worthwhile. (author)

Effect of Mineral Composition on Thermoluminescence Analysis of Irradiated Garlics

International Nuclear Information System (INIS)

Sookkasem, Atitaya; Wanwisa, Sudprasert; Vitittheeranon, Arag

2009-07-01

Full text: Thermoluminescence (TL) is one of the most popular techniques used for identification of irradiated foods such as spices, herbs and dried fruits in accordance with the Codex Standards. TL analysis is based on the determination of TL of adhering or contaminating minerals in foods. This research aimed to study the effect of mineral composition on the TL intensity. The composited minerals were extracted from 3 types of non-irradiated and irradiated garlic powders by sodium polytungstate solution. X-ray diffraction (XRD) spectroscopy was employed to investigate the type and amount of minerals present in garlic powders. TL of separated minerals were analysed using a Harshaw 4500 TL reader. The results showed that the mineral composition of garlic powders was mainly quartz of varying amounts depending on types of garlics. The TL intensity linearly increased with the amount of quartz present in the samples. It can be concluded that the amount of minerals affect the TL intensity which might influence the identification of irradiated tretment of garlics by thermoluminescence

Investigation of dosimetric characteristics of the high sensitivity LiF:Mg,Cu,P thermoluminescent dosemeter and its applications in diagnostic radiology

International Nuclear Information System (INIS)

Fung, K.K.L.

2000-12-01

The recent introduction and development of the thermoluminescent (T.L.) phosphor material LiF:Mg,Cu,P (usually named TLD100H or GR200A) has aroused intense interest of scientists in the field of radiation dosimetry due to its very favourable dosimetric characteristics. Both conventional LiF:Mg,Ti (TLD100) and LiF:Mg,Cu,P T.L. phosphors are tissue-equivalent but GR200A outperforms in respect of its very much higher sensitivity, by a factor of greater than 25, and a dose detection threshold of less than 1 μGy. A reproducible readout and annealing regime was developed in the initial part of this study with the newly installed automatic TLD (Thermoluminescence Dosimetry) apparatus in the X-ray and Radiation Physics Laboratories of the Hong Kong Polytechnic University. Basic dosimetric characteristics of this T.L. dosemeter (supplied by Harshaw-Bicron Co.) were then investigated. This paved the foundation for subsequent selected novel application studies in diagnostic radiology. Dosimetric characteristics which included linearity, reproducibility, batch uniformity, energy response, and minimum detectable dose were studied using X-rays in the commonly used diagnostic radiology energy range. Favourable dosimetric characteristics were observed from this T.L. phosphor, which agrees well with published studies. The effect of the number of thermal treatment cycles in the initialisation process on dosimetric properties of this T.L. phosphor was also investigated. This study exploits the favourable dosimetric properties of these T.L. dosemeters in some selected novel dosimetric applications in diagnostic radiology with an anthropomorphic phantom using facilities both in these laboratories and also in radiology departments of various district hospitals in Hong Kong. Radiation absorbed dose from the direct or scattered beam, at critical sites inside and on the surface of the phantom, were measured in these radiological studies. The special focus in some of these studies was to

Investigation of dosimetric characteristics of the high sensitivity LiF:Mg,Cu,P thermoluminescent dosemeter and its applications in diagnostic radiology

Energy Technology Data Exchange (ETDEWEB)

Fung, K.K.L

2000-12-01

The recent introduction and development of the thermoluminescent (T.L.) phosphor material LiF:Mg,Cu,P (usually named TLD100H or GR200A) has aroused intense interest of scientists in the field of radiation dosimetry due to its very favourable dosimetric characteristics. Both conventional LiF:Mg,Ti (TLD100) and LiF:Mg,Cu,P T.L. phosphors are tissue-equivalent but GR200A outperforms in respect of its very much higher sensitivity, by a factor of greater than 25, and a dose detection threshold of less than 1 {mu}Gy. A reproducible readout and annealing regime was developed in the initial part of this study with the newly installed automatic TLD (Thermoluminescence Dosimetry) apparatus in the X-ray and Radiation Physics Laboratories of the Hong Kong Polytechnic University. Basic dosimetric characteristics of this T.L. dosemeter (supplied by Harshaw-Bicron Co.) were then investigated. This paved the foundation for subsequent selected novel application studies in diagnostic radiology. Dosimetric characteristics which included linearity, reproducibility, batch uniformity, energy response, and minimum detectable dose were studied using X-rays in the commonly used diagnostic radiology energy range. Favourable dosimetric characteristics were observed from this T.L. phosphor, which agrees well with published studies. The effect of the number of thermal treatment cycles in the initialisation process on dosimetric properties of this T.L. phosphor was also investigated. This study exploits the favourable dosimetric properties of these T.L. dosemeters in some selected novel dosimetric applications in diagnostic radiology with an anthropomorphic phantom using facilities both in these laboratories and also in radiology departments of various district hospitals in Hong Kong. Radiation absorbed dose from the direct or scattered beam, at critical sites inside and on the surface of the phantom, were measured in these radiological studies. The special focus in some of these studies was to

Measurement of dose enhancement close to high atomic number media using optical fibre thermoluminescence dosimeters

International Nuclear Information System (INIS)

Alalawi, Amani I.; Hugtenburg, R.P.; Abdul Rahman, A.T.; Barry, M.A.; Nisbet, A.; Alzimami, Khalid S.; Bradley, D.A.

2014-01-01

Present interest concerns development of a system to measure photoelectron-enhanced dose close to a tissue interface using analogue gold-coated doped silica-fibre thermoluminescence detectors and an X-ray set operating at 250 kVp. Study is made of the dose enhancement factor for various thicknesses of gold; measurements at a total gold thickness of 160 nm (accounting for incident and exiting photons) produces a mean measured dose enhancement factor of 1.33±0.01 To verify results, simulations of the experimental setup have been performed. - Highlights: • Dose enhancement • Thermoluminescence dosimeter • Monte Carlo simulation

Kinetics of the generation of the petroleum: Principles and application in the Colombian basins

International Nuclear Information System (INIS)

Goncalves, F T T; Garcia, D F; Penteado, H L B; Giraldo, B N; Bedregal, R P; Gomez

2001-01-01

Most of the mathematical models that describe the conversion of kerogen into petroleum are based on the formulations of first-order kinetics. Although the application of such models requires the knowledge of the kinetic parameters (activation energies and frequency factor) of the kerogen, the usual practice in basin modeling studies is to use kinetic data of standard kerogen types (I, II or III) when measured data are not available. In this study, Rock-Eval pyrolysis under different heating rates and numerical optimization techniques were used to determine the kinetic parameters of cretaceous and tertiary source rocks of the upper Magdalena and llanos basins. The obtained kinetic parameters revealed a significant variability, which appears to be unrelated to the kerogen type classification based on hydrogen and oxygen indices. Modeling exercises under a constant heating rate (1.25 degrades C/M.y., 274.5K/M.y.) using the measured kinetic data indicates that kerogen conversion of organic facies with distinct kinetic parameters may be out of phase by 20-30M.y. therefore, petroleum generation and expulsion history might be longer and more complex than if the kinetic behavior of these rocks was considered homogeneous. These differences are critical in defining the timing between petroleum generations a trap formation/destruction, particularly in the case of the Colombian sedimentary basins, characterized by a highly complex tectonic evolution

Thermoluminescence investigation of sol–gel derived and γ-irradiated SnO{sub 2}:Eu{sup 3+} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Bajpai, Namrata [Department of Chemistry, Government E. R. R. PG Science College, Bilaspur 495006, Chhattisgarh (India); Khan, S.A. [Government College Seepat, Bilaspur 495555, Chhattisgarh (India); Kher, R.S. [Department of Physics, Government E. R. R. PG Science College, Bilaspur 495006, Chhattisgarh (India); Bramhe, Namita [SOS in Physics and Astrophysics, Pt. Ravishankar Shukla University Raipur 492001, Chhattisgarh (India); Dhoble, S.J. [Department of Physics, RTM Nagpur University, Nagpur 440033, Maharashtra (India); Tiwari, Ashish, E-mail: ashisht048@gmail.com [Department of Chemistry, Government Lahiri College, Chirimiri, Korea 497449, Chhattisgarh (India)

2014-01-15

Nanocrystalline tin oxide (IV) doped with Eu{sup 3+} has been synthesized by sol–gel technique. The prepared SnO{sub 2}:Eu{sup 3+} nanoparticles were calcined and characterized by XRD, SEM, TEM and FTIR. The XRD analysis revealed well crystallised tetragonal rutile phase. Electron microscopy showed spherical morphologies with an average size of 15–20 nm. The thermoluminescence (TL) properties of SnO{sub 2}:Eu{sup 3+} nanoparticles were investigated after γ-irradiation using {sup 60}Co source at room temperature. The TL glow curve showed variation in TL peak intensity as the concentration of dopant is changed. It has been found that TL response of linear in the range 0.5–2.0 kGy. This paper discusses about the optimal doping concentration of Europium in SnO{sub 2} nanoparticles and its dosimetric application has also been studied. -- Highlights: • Thermoluminescence (TL) properties of SnO{sub 2}:Eu{sup 3+} nanoparticles were investigated after γ-irradiation. • TL glow curve showed variation in TL peak intensity as the concentration of dopant is changed. • Optimal TL intensity was obtained for SnO{sub 2}:Eu{sub 0.5}. • TL response was found to be linear in the range 0.5–2.0 kGy.

Gamma ray induced thermoluminescence studies of yttrium (III oxide nanopowders doped with gadolinium

Directory of Open Access Journals (Sweden)

Raunak Kumar Tamrakar

2014-10-01

Full Text Available Y2O3:Gd3+ nanophosphor was prepared by the solid state reaction method. Systematic studies have been done to investigate the structural and optical properties of the gadolinium doped Y2O3 phosphor. The prepared phosphor was characterized by using X-ray diffractometer (XRD, scanning electron microscopy (SEM, transmission electron microscopy and UV–VIS–NIR spectrophotometer. The XRD patterns reveal that these prepared phosphors have cubic phase crystal structure. SEM and TEM images showed uniform doping of the material over the entire materials. The energy band gap for gadolinium doped Y2O3 phosphor was revealed from the optical studies and was found to 5.1 eV. The prepared phosphors were also examined by thermoluminescence technique. The kinetic parameters like trap depth, frequency factor were calculated by using the Peak shape method, which are discussed in details. The TL Glow curves were fitted in CGCD (computerized glow curve convolution deconvolution technique & trapping parameters calculated. The TL parameters such as activation energy for deconvoluted peak were found in the range of 0.82–2.24 eV. The frequency factor is of the order of between of 1.78 × 1012 and 9.84 × 1020 s−1.

Incompatibility of sensitisation and re-estimation of lithium fluoride thermoluminescent phosphor

International Nuclear Information System (INIS)

Bartlett, D.T.; Sandford, D.J.

1978-01-01

A technique of useful sensitisation of lithium fluoride thermoluminescent phosphor has been reported by Mayhugh and Fullerton, (USAEC Report COO-1105-209, 1974). This technique differs from that previously described (Cameron and Zimmerman, USAEC Report COO-1105-102, 1965) in that during the anneal at 300 degrees C which follows the high pre-dose, the phosphor is simultaneously exposed to 254 nm ultraviolet light. It is reported that this method removes interfering centres and hence reduces the lowest detectable dose. Sensitisation also has the advantages of improved tissue equivalence and increased range of linearity. However, a disadvantage of both techniques of sensitisation is that for sensitised phosphor, absorbed doses cannot be re-estimated by photo-transferred thermoluminescence. Results are compared for discs of lithium fluoride in PTFE, some of which were sensitised by each method, and some left unsensitised. It is concluded that for routine personal dosimetry the disadvantages of the loss of the facility to re-estimate absorbed dose outweighs the reported advantages of sensitisation. (author)

Proposal of a methodology for quality control in thermoluminescent dosimetry laboratory

International Nuclear Information System (INIS)

Feital, Joao Carlos da S.; Almeida, Claudio Domingues de; Bezerra, Marcos A.

2005-01-01

Taken into account that in thermoluminescence dosimetry adequate selection procedures as well as accurate TLD readings are necessary, this paper presents results of methodology that can be applied as part of quality control programs in thermoluminescence dosimetry laboratories. For the experiment, a set of 200 TLDs ( LiF 100 ) were used and 9 from which were selected, a standard source of Cs -137 , a PTW kiln, a TL 'Harshaw' reader - model 5500 operating under the 'Win Rem' software and a Sr 90 / Y 90 'Bicron' irradiator. In the proceeding the selected dosimeters were irradiated and read 28 times during 18 months, then by one of the standard deviation properties, values up to 14 % were found, for a confidence level of 95 %. The results found and the bibliographic data related to the responses (arbitrary reading) in the crystals used in TLDs, have shown that this methodology can be applied in quality control programs. (author)

Experimental determination of the photon-energy dependent dose-to-water response of TLD600 and TLD700 (LiF:Mg,Ti) thermoluminescence detectors

Energy Technology Data Exchange (ETDEWEB)

Schwahofer, Andrea [Vivantes Clinic Neukoelln, Berlin (Germany). Dept. of Radiation Therapy; German Cancer Research Center, Heidelberg (Germany). Medical Physics in Radiation Therapy; Feist, Harald [Munich Univ. (Germany). Dept. of Radiation Therapy; Georg, Holger [PTW Freiburg (Germany). Calibration Lab.; Haering, Peter; Schlegel, Wolfgang [German Cancer Research Center, Heidelberg (Germany). Medical Physics in Radiation Therapy

2017-05-01

The aim of this study has been the experimental determination of the energy dependent dose-to-water response of TLD600 and TLD700 thermoluminescent detectors (Harshaw) in X-ray beams with mean photon energies from about 20 to 200 keV in comparison with {sup 60}Co gamma rays and 6 MV X-rays. Experiments were carried out in collaboration with the German secondary standard laboratory PTW Freiburg. The energy dependent relative responses of TLD600 and TLD700 thermoluminescence detectors were determined at radiation qualities between 30 kV{sub p} and 280 kV{sub p}. The overall uncertainty of the measured values was characterized by standard deviations varying from 1.2 to 3%. The present results agree with previous studies on the energy dependent dose-to-water response of TLD100. As an application example, the results were used to measure doses associated with X-ray imaging in image-guided radiotherapy.

Calculation of the relative efficiency of thermoluminescent detectors to space radiation

International Nuclear Information System (INIS)

Bilski, P.

2011-01-01

Thermoluminescent (TL) detectors are often used for measurements of radiation doses in space. While space radiation is composed of a mixture of heavy charged particles, the relative TL efficiency depends on ionization density. The question therefore arises: what is the relative efficiency of TLDs to the radiation present in space? In the attempt to answer this question, the relative TL efficiency of two types of lithium fluoride detectors for space radiation has been calculated, based on the theoretical space spectra and the experimental values of TL efficiency to ion beams. The TL efficiency of LiF:Mg,Ti detectors for radiation encountered at typical low-Earth’s orbit was found to be close to unity, justifying a common application of these TLDs to space dosimetry. The TL efficiency of LiF:Mg,Cu,P detectors is significantly lower. It was found that a shielding may have a significant influence on the relative response of TLDs, due to changes caused in the radiation spectrum. In case of application of TLDs outside the Earth’s magnetosphere, one should expect lower relative efficiency than at the low-Earth’s orbit.

Dose measurements in dental radiology using thermoluminescent dosimetry;Medicoes de dose em radiodiagnostico odontologico utilizando dosimetria termoluminescente

Energy Technology Data Exchange (ETDEWEB)

Chiara, Ana Claudia M. de; Costa, Alessandro M. [Universidade de Sao Paulo (FFCLRP/USP), Ribeirao Preto, SP (Brazil). Faculdade de Filosofia, Ciencias e Letras; Pardini, Luiz Carlos [Universidade de Sao Paulo (FORP/USP), Ribeirao Preto, SP (Brazil). Faculdade de Odontologia

2009-07-01

The aim of this work was the implementation of a code of practice for dosimetry in dental radiology using the technique of thermoluminescent dosimetry. General principles for the use of thermoluminescent dosimeters were followed. The irradiations were performed using ten X-ray equipment for intra-oral radiography and an X-ray equipment for panoramic radiography. The incident air kerma was evaluated for five different exposure times used in clinical practice for intra-oral radiographs. Using a backscatter factor of 1.2, it was observed that approximately 40% of the entrance skin dose values found for intra-oral radiographs are above the diagnostic reference level recommended in national regulation. Different configurations of voltage and current were used representing the exposure as a child, woman and man for panoramic radiographs. The results obtained for the air kerma area product were respectively 53.3 +- 5.2 mGy.cm{sup 2}, 101.5 +- 9.5 mGy.cm{sup 2} and 116.8 +- 10.4 mGy.cm{sup 2}. The use of thermoluminescent dosimetry requires several procedures before a result is recorded. The use of dosimeters with ionization chambers or semiconductors provides a simple and robust method for routine measurements. However, the use of thermoluminescent dosimetry can be of great value to large-scale surveys to establish diagnostic reference levels. (author)

Development of imploding liners with kinetic energies > 100 MJ and their applications

International Nuclear Information System (INIS)

Reinovsky, R.E.; Ekdahl, C.A.

1996-01-01

The Los Alamos program in High Energy Density Physics is developing high performance imploding liners as sources of high energy density environments for experimental physics applications. High performance liners are, for these purposes, liners with high velocity, 100 MJ or more kinetic energy at 20-50 MJ/cm of height. They must have sufficient azimuthal symmetry, axial uniformity and density to perform as high quality impactors on central, cylindrical targets. Scientific applications of such liners are numerous and varied. For example, the properties of materials at extreme energy densities can be assessed in such an experimental environment. The physics of plasmas near solid density can be studied and hydrodynamics experiments at high Mach number (above 5?) in materials that are near solid density and significantly ionized can be conducted. In addition, liners with substantial kinetic energy and good integrity at velocities of one to a few cm/microsec make good implosion drivers for fusion plasmas in the context of magnetized target fusion and MAGO

Curve thermoluminescent analysis of ZrO2 doped with nanoparticles and Ag nano fibers

International Nuclear Information System (INIS)

Mendoza A, D.; Villa S, G.; Gutierrez W, C.; Perez H, R.; Gonzalez M, P.

2008-01-01

This paper presents the results obtained from the analysis of the high temperature thermoluminescence response induced by UV radiation in pure zirconium (ZrO 2 ) and doped with Ag nanoparticles and Ag nano fibers. The zirconium samples were obtained by the sol-gel method and irradiated with a UV lamp for different times. The results showed that the presence of the dopants change the characteristics of the traps associated with the high temperature peak which is located at 230 C for pure zirconium, and that the greater influence is due the presence of Ag nano fibers, inducing a shift to lower temperatures. It also presents the thermoluminescence response as a function of irradiation time. (Author)

Application of radioisotope XRF and thermoluminescence (TL) dating in investigation of pottery from Tell AL-Kasra archaeological site, Syria.

Science.gov (United States)

Abboud, R; Issa, H; Abed-Allah, Y D; Bakraji, E H

2015-11-01

Statistical analysis based on chemical composition, using radioisotope X-ray fluorescence, have been applied on 39 ancient pottery fragments coming from the excavation at Tell Al-Kasra archaeological site, Syria. Three groups were defined by applying Cluster and Factor analysis statistical methods. Thermoluminescence (TL) dating was investigated on three sherds taken from the bathroom (hammam) on the site. Multiple aliquot additive dose (MAAD) was used to estimate the paleodose value, and the gamma spectrometry was used to estimate the dose rate. The average age was found to be 715±36 year. Copyright © 2015 Elsevier Ltd. All rights reserved.

Preliminary Development of the MARS/FREK Spatial Kinetics Coupled System Code for Square Fueled Fast Reactor Applications

International Nuclear Information System (INIS)

Bae, Moo Hoon; Joo, Han Gyu

2009-01-01

Incorporation of a three-dimensional (3-D) reactor kinetics model into a system thermal-hydraulic (T/H) code enhances the capability to perform realistic analyses of the core neutronic behavior and the plant system dynamics which are coupled each other. For this advantage, several coupled system T/H and spatial kinetics codes, such as RELAP/PARCS, RELAP5/ PANBOX, and MARS/MASTER have been developed. These codes, however, so far limited to LWR applications. The objective of this work is to develop such a coupled code for fast reactor applications. Particularly, applications to lead-bismuth eutectic (LBE) cooled fast reactor are of interest which employ open square lattices. A fast reactor kinetics code applicable to square fueled cores called FREK is coupled the LBE version of the MARS code. The MARS/MASTER coupled code is used as the reference for the integration. The coupled code MARS/FREK is examined for a conceptual reactor called P-DEMO which is being developed by NUTRECK. In order to check the validity of the coupled code, however, the OECD MSLB benchmark exercise III calculation is solved first

Imprints left by natural radioactivity in geological materials: uranium fission tracks and thermoluminescence applications in earth sciences

International Nuclear Information System (INIS)

Broquet, P.; Chambaudet, A.; Rebetez, M.; Charlet, J.M.

1994-01-01

In a rock, all minerals which contain uranium are host to a number of spontaneous fission phenomena forming a single damaged area called a ''latent track'', observations of which may lead to dating, uranium mapping and finding paleo-geo-thermometers (thermal history, used in oil exploration). The radioactive elements during the decay process release energy which is trapped as electrons into the physical or chemical defects of the crystalline lattice; this energy can be later released by heating the mineral (thermic stimulated luminescence); the thermoluminescence is characterized by a glow which spectrum constitutes a typical feature of the mineral, its crystallization conditions and the subsequent evolution of the material. Natural and induced glow curve may be produced. 6 figs., 52 refs

Tantalum high-temperature oxidation kinetics

International Nuclear Information System (INIS)

Grigor'ev, Yu.M.; Sarkisyan, A.A.; Merzhanov, A.G.

1981-01-01

Kinetics of heat release and scale growth during tantalum oxidation within 650-1300 deg C temperature range in oxygen-containing media is investigated. Kinetic equations and temperature and pressure dependences of constants are ound Applicability of the kinetic Lorie mechanism for the description of the tantalum oxidation kinetics applicably to rapid-passing processes is shown. It is stated that the process rate (reaction ability) is determined by adsorption desorption factors on the external surface of the ''protective'' oxide for the ''linear'' oxidation stage [ru

Dosimetric characteristics of ultraviolet and x-ray-irradiated KBr:Eu2+ thermoluminescence crystals

International Nuclear Information System (INIS)

Melendrez, R.; Perez-Salas, R.; Aceves, R.; Piters, T.M.; Barboza-Flores, M.

1996-01-01

Thermoluminescence (TL) characteristics of KBr:Eu 2+ (150 ppm) previously exposed to ultraviolet (UV) light (200 endash 300 nm) and x-ray radiation at room temperature have been determined. The TL glow curve of UV-irradiated samples is composed of six peaks located at 337, 384, 402, 435, 475, and 510 K. The TL glow curves of x-irradiated samples show mainly a TL peak around 384 K. The TL intensities of UV-irradiated (402 and 510 K glow peaks) and x-irradiated specimens present a linear dependence as a function of radiation dose as well as fading stability 300 s after irradiation. These results further enhance the possibilities of using europium-doped materials in nonionizing (actinic region) and ionizing radiation detection and dosimetry applications. copyright 1996 American Institute of Physics

Evaluation of new and conventional thermoluminescent phosphors for environmental monitoring using automated thermoluminescent dosimeter readers

International Nuclear Information System (INIS)

Rathbone, B.A.; Endres, A.W.; Antonio, E.J.

1994-10-01

In recent years, there has been considerable interest in a new generation of super-sensitive thermoluminescent (TL) phosphors for potential use in routine personnel and environmental monitoring. Two of these phosphors, α-Al 2 O 3 :C and LiF:Mg,Cu,P, are evaluated in this paper for selected characteristics relevant to environmental monitoring, along with two conventional phosphors widely used in environmental monitoring, LiF:Mg,Ti and CaF 2 :Dy. The characteristics evaluated are light-induced fading, light-induced background, linearity and variability at low dose, and the minimum measurable dose. These characteristics were determined using an automated commercial dosimetry system (Harshaw System 8800) and routine processing protocols. Annealing and readout protocols for each phosphor were optimized for use in a large-scale environmental monitoring program

A Global Modeling Framework for Plasma Kinetics: Development and Applications

Science.gov (United States)

Parsey, Guy Morland

The modern study of plasmas, and applications thereof, has developed synchronously with com- puter capabilities since the mid-1950s. Complexities inherent to these charged-particle, many- body, systems have resulted in the development of multiple simulation methods (particle-in-cell, fluid, global modeling, etc.) in order to both explain observed phenomena and predict outcomes of plasma applications. Recognizing that different algorithms are chosen to best address specific topics of interest, this thesis centers around the development of an open-source global model frame- work for the focused study of non-equilibrium plasma kinetics. After verification and validation of the framework, it was used to study two physical phenomena: plasma-assisted combustion and the recently proposed optically-pumped rare gas metastable laser. Global models permeate chemistry and plasma science, relying on spatial averaging to focus attention on the dynamics of reaction networks. Defined by a set of species continuity and energy conservation equations, the required data and constructed systems are conceptually similar across most applications, providing a light platform for exploratory and result-search parameter scan- ning. Unfortunately, it is common practice for custom code to be developed for each application-- an enormous duplication of effort which negatively affects the quality of the software produced. Presented herein, the Python-based Kinetic Global Modeling framework (KGMf) was designed to support all modeling phases: collection and analysis of reaction data, construction of an exportable system of model ODEs, and a platform for interactive evaluation and post-processing analysis. A symbolic ODE system is constructed for interactive manipulation and generation of a Jacobian, both of which are compiled as operation-optimized C-code. Plasma-assisted combustion and ignition (PAC/PAI) embody the modernization of burning fuel by opening up new avenues of control and optimization

Study of thermoluminescence response of purple to violet amethyst quartz from Balikesir, Turkey

International Nuclear Information System (INIS)

Nur, N.; Yeğingil, Z.; Topaksu, M.; Kurt, K.; Doğan, T.; Sarıgül, N.; Yüksel, M.; Altunal, V.; Özdemir, A.; Güçkan, V.; Günay, I.

2015-01-01

Highlights: • We reported on dosimetric characterisation of natural amethyst quartz specimens from Turkey, using TL technique. • The thermoluminescence characterisation tests were performed under the beta radiation exposure. • The IT peaks ∼230 °C show superlinear dose response behavior (g(D) > 1) between 1 Gy and 5 kGy. The HT peaks ∼300 °C show linear behavior (g(D) = 1) at low dose levels (1 < D < 20 Gy) and superlinearity (g(D) > 1) between 20 Gy < D < 2 kGy. • Deviations were determined for recycling measurements for various dose values of 0.1, 0.5, 0.8 and 1 kGy. • Amethyst quartz has great potential to be investigated for dosimetry purpose. - Abstract: In thermoluminescence (TL) dosimetry, the phosphor amethyst quartz as a thermoluminescent, appears to be one of the materials arousing the highest interest. In this study the dosimetric characteristics of natural amethyst quartz crystals collected from Balikesir–Dursunbey (Turkey) were investigated for the purpose of determination of the general properties that phosphors should have in order to be useful for thermoluminescence dosimetry. The natural thermoluminescence was drained by annealing the powder samples at 450 °C for 1.5 h. The effects of high temperature annealing, dose response curves, glow curves after a postirradiation annealing, reusability of the samples and storage of trapped electrons in dark at room temperature were clarified through irradiating the samples with the desired exposures by 90 Sr/ 90 Y beta particles. Isothermal annealing before and after irradiation was found to have a definite effect upon the TL glow curve of amethyst crystal powder. The same sample varied in sensitivity depending upon its previous thermal and radiation history. The peak heights of the glow peaks were examined with respect to dose response at dose levels between 1 Gy and 5 kGy. The intermediate temperature (IT) and high temperature (HT) peaks of 230 °C and 300 °C, respectively, exhibit dose�

Study of thermoluminescence response of purple to violet amethyst quartz from Balikesir, Turkey

Energy Technology Data Exchange (ETDEWEB)

Nur, N., E-mail: nnur@adiyaman.edu.tr [Adiyaman University, Engineering Faculty, Department of Electrical and Electronic Engineering, 02040 Adiyaman (Turkey); Yeğingil, Z.; Topaksu, M. [Cukurova University, Art and Sciences Faculty, Physics Department, 01330 Adana (Turkey); Kurt, K. [University of Mersin, Science and Art Faculty, Physics Department, 33343 Mersin (Turkey); Doğan, T. [Cukurova University, Vocational School of Imamoglu, Department of Technical Programs, 01700 Adana (Turkey); Sarıgül, N. [Institute of Nuclear Science, Hacettepe University, 06532 Ankara (Turkey); Yüksel, M.; Altunal, V.; Özdemir, A.; Güçkan, V. [Cukurova University, Art and Sciences Faculty, Physics Department, 01330 Adana (Turkey); Günay, I. [Cukurova University, Medicine Faculty, Biophysics Department, Adana (Turkey)

2015-09-01

Highlights: • We reported on dosimetric characterisation of natural amethyst quartz specimens from Turkey, using TL technique. • The thermoluminescence characterisation tests were performed under the beta radiation exposure. • The IT peaks ∼230 °C show superlinear dose response behavior (g(D) > 1) between 1 Gy and 5 kGy. The HT peaks ∼300 °C show linear behavior (g(D) = 1) at low dose levels (1 < D < 20 Gy) and superlinearity (g(D) > 1) between 20 Gy < D < 2 kGy. • Deviations were determined for recycling measurements for various dose values of 0.1, 0.5, 0.8 and 1 kGy. • Amethyst quartz has great potential to be investigated for dosimetry purpose. - Abstract: In thermoluminescence (TL) dosimetry, the phosphor amethyst quartz as a thermoluminescent, appears to be one of the materials arousing the highest interest. In this study the dosimetric characteristics of natural amethyst quartz crystals collected from Balikesir–Dursunbey (Turkey) were investigated for the purpose of determination of the general properties that phosphors should have in order to be useful for thermoluminescence dosimetry. The natural thermoluminescence was drained by annealing the powder samples at 450 °C for 1.5 h. The effects of high temperature annealing, dose response curves, glow curves after a postirradiation annealing, reusability of the samples and storage of trapped electrons in dark at room temperature were clarified through irradiating the samples with the desired exposures by {sup 90}Sr/{sup 90}Y beta particles. Isothermal annealing before and after irradiation was found to have a definite effect upon the TL glow curve of amethyst crystal powder. The same sample varied in sensitivity depending upon its previous thermal and radiation history. The peak heights of the glow peaks were examined with respect to dose response at dose levels between 1 Gy and 5 kGy. The intermediate temperature (IT) and high temperature (HT) peaks of 230 °C and 300 °C, respectively

Thermoluminescent dosimetry in veterinary diagnostic radiology

International Nuclear Information System (INIS)

Hernández-Ruiz, L.; Jimenez-Flores, Y.; Rivera-Montalvo, T.; Arias-Cisneros, L.; Méndez-Aguilar, R.E.; Uribe-Izquierdo, P.

2012-01-01

This paper presents the results of Environmental and Personnel Dosimetry made in a radiology area of a veterinary hospital. Dosimetry was realized using thermoluminescent (TL) materials. Environmental Dosimetry results show that areas closer to the X-ray equipment are safe. Personnel Dosimetry shows important measurements of daily workday in some persons near to the limit established by ICRP. TL results of radiation measurement suggest TLDs are good candidates as a dosimeter to radiation dosimetry in veterinary radiology. - Highlights: ► Personnel dosimetry in laboratory veterinary diagnostic was determined. ► Student workplaces are safe against radiation. ► Efficiency value of apron lead was determined. ► X-ray beams distribution into veterinarian laboratory was measured.

Effect of low irradiation temperature on the thermoluminescent response of doped crystal NaCl:XCl2 :MnCl2(X=Ca, Cd)

International Nuclear Information System (INIS)

Ortiz M, A.; Cruz Z, E.; Furetta, C.; Kitis, G.

2009-10-01

Production of crystalline materials suitable thermoluminescent properties over a wide range of doses is becoming more important to evaluate different radiation fields. However, the thermoluminescence response and the structure of the glow curves may be modified by the participation of defects to low irradiation temperature. In this work it is analyzed the effect of the irradiation temperature, 77 and 200 K on the thermoluminescence response of crystal NaCl:XCl 2 :MnCl 2 (X=Ca, Cd) doubly doped. The glow curves obtained were analyzed using a deconvolution program of CGCD, and the response linearity was analyzed by supra linearity index. (Author)

Comparative measurements of soil gas radon concentration using thermoluminescent and track detectors

Czech Academy of Sciences Publication Activity Database

Turek, Karel; Gelev, M.; Dimov, I.

2004-01-01

Roč. 38, spec. iss. (2004), s. 843-846 ISSN 1350-4487 Institutional research plan: CEZ:AV0Z1048901 Keywords : soil gas * radon concentration * thermoluminescent detectors Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 0.664, year: 2004

Obtention of a thermoluminescent material for dosimetry of ionizing radiation; Obtencion de un material termoluminiscente para dosimetria de la radiacion ionizante

Energy Technology Data Exchange (ETDEWEB)

Gonzalez M, P R

1990-07-01

The thermoluminescent dosemeters are small crystals which suffer changes in their structure by the radiation effect, being displaced the electrons toward higher energy levels. On heating the previously irradiated crystals, the electrons come back to their base state emitting light photons. The light quantity emitted is proportional to the received radiation dose. The light quantity emitted is proportional to the received radiation dose. The lithium fluoride is one of the thermoluminescent materials considered as tissue equivalents by having a low effective atomic number (Z{sub ef}). At present, the more used commercial product used of this type is the TLD-100*. In this work the obtained results in the preparation of the lithium fluoride thermoluminescent material are presented. This is activated with magnesium (Mg) and titanium (Ti), which we have labelled as: LiF: Mg, Ti. The results from the tests performed for verifying his thermoluminescent properties are presented too, as powder form as in pellets form. These tests were performed in simultaneous form with TLD-100 samples, which is considered as reference. The LiF: Mg, Ti thermoluminescent material manufactured in the ININ presents similar dosimetric characteristics to those ones of the TLD-100. Therefore being able to replace the imported dosemeters. * (TLD-100 is a commercial trademark registered by Harshaw/Filtrol (US) for LiF: Mg, Ti Tl dosemeters) (Author)

Thermal activation energies and peak temperatures in thermoluminescence of LiF (Mg, Ti) and CaF2:Mn at low temperatures

International Nuclear Information System (INIS)

Jain, V.K.; Jahan, M.S.

1987-01-01

Low temperature thermoluminescence (TL) of LiF (TLD-100) and CaF 2 :Mn is studied. The TLD-100 is dosimetry grade LiF manufactured by Harshaw-Filtrol Partnership. It is believed that it contains about 200 ppm Mg and 7 ppm Ti as impurities. In each case the glow curve shows several peaks. Some of these peaks are quite strong and develop with dose. Others are weak. Kinetic parameters are calculated for the former using the initial rise method and Chen's modified formula. The two sets of values are found to be different. Some authors have suggested empirical formulae connecting peak temperature, T m , and activation energy, E. The empirical relations are tried for the values of E calculated, as well as those available in literature (for T m above room temperature). It is found that a fairly reasonable relation existed between E and T m . (author)

Comparative study among calibration methods of clinical applicators of beta radiation

International Nuclear Information System (INIS)

Antonio, Patricia de Lara

2009-01-01

90 Sr+ 90 Y clinical applicators are instruments used in brachytherapy procedures and they have to be periodically calibrated, according to international standards and recommendations. In this work, four calibration methods of dermatological and ophthalmic applicators were studied, comparing the results with those given by the calibration certificates of the manufacturers. The methods included the use of the standard applicator of the Calibration Laboratory (LCI), calibrated by the National Institute of Standards and Technology; an Amersham applicator (LCI) as reference; a mini-extrapolation chamber developed at LCI as an absolute standard; and thermoluminescent dosimetry. The mini-extrapolation chamber and a PTW commercial extrapolation chamber were studied in relation to their performance through quality control tests of their response, as leakage current, repeatability and reproducibility. The distribution of the depth dose in water, that presents high importance in dosimetry of clinical applicators, was determined using the mini extrapolation chamber and the thermoluminescent dosimeters. The results obtained were considered satisfactory for the both cases, and comparable to the data of the IAEA (2002) standard. Furthermore, a dosimetry postal kit was developed for the calibration of clinical applicators using the thermoluminescent technique, to be sent to clinics and hospitals, without the need of the transport of the sources to IPEN for calibration. (author)

Determination of the dose rapidity of a 90 Sr beta radiation source using thermoluminescent dosemeters

International Nuclear Information System (INIS)

Gonzalez M, P.R.; Azorin N, J.; Rivera M, T.

2000-01-01

The thermoluminescent dosemeters developed in Mexico, have been used efficiently in environmental and personal dosimetry. When the dose rate of some source is not known can be estimated with the use of thermoluminescent dosemeters taking in account the geometrical array used in the irradiations for reproducibility of the results in posterior irradiations. In this work it was estimated the dose rate of a 90 Sr- 90 Y beta radiation source which is property of the Nuclear Sciences Institute, UNAM, therefore it was l ended to the Metropolitan Autonomous University- Iztapalapa Unit for the characterization of new Tl materials, taking account of the institutional collaboration agreements. (Author)

Thermoluminescence of KI:Eu2+ Stimulated by Ultraviolet Irradiation at Different Temperatures

International Nuclear Information System (INIS)

Aguirre de Carcer, I.; Jaque, F.; Townsend, P.D.

1999-01-01

The thermoluminescence (TL) of KI:Eu 2+ after ultraviolet (254 nm) irradiation at different temperatures from -40 deg. C to +40 deg. C has been studied. Two main glow peaks and some minor features have been identified on the thermoluminescence glow curves. Irradiating at low temperature gives a strong peak at γ5 deg. C and a less pronounced one at 230 deg. C. The TL glow peak emission spectra were analysed as consisting of the addition of several Gaussian shaped emission bands. The position of the Gaussian peaks, and their widths, are coincident with divalent europium emission at different sites of the KI:Eu 2+ system. A new emission band centred at 3.05 eV, 0.16 eV FWHM for Eu 2+ has been observed from the TL emission spectra. The changes in the spectral distribution of the TL emission with irradiation temperature are discussed. (author)

Assessing the impact of azadirachtin application to soil on ureaseactivity and its kinetic parameters

OpenAIRE

KIZILKAYA, RIDVAN; SAMOFALOVA, IRAIDA; MUDRYKH, NATALYA; MİKAİLSOY, FARİZ; AKÇA, İZZET; SUSHKOVA, SVETLANA; MINKINA, TATIANA

2015-01-01

Abstract: The kinetic parameters of soil urease have attracted considerable attention; however, little information is available on its kinetic parameters and behaviors in response to azadirachtin application to the soil. A short (14-day) field experiment was conducted using Albic Luvisol soil (loam texture; pH 6.70; electrical conductivity 0.81 dS m-1; CaCO3 content 0.04%; total organic carbon 0.99%) as the experimental soil in the Perm region of the Russian Federation to investigate the effe...

Systematic development of new thermoluminescence and optically stimulated luminescence materials

Energy Technology Data Exchange (ETDEWEB)

Yukihara, E.G., E-mail: eduardo.yukihara@okstate.edu [Physics Department, 145 Physical Sciences II, Oklahoma State University, Stillwater, OK 74078 (United States); Milliken, E.D.; Oliveira, L.C. [Physics Department, 145 Physical Sciences II, Oklahoma State University, Stillwater, OK 74078 (United States); Orante-Barron, V.R. [Departamento de Investigacion en Polimeros y Materiales, Universidad de Sonora, Hermosillo, Sonora 83000, Mexico (Mexico); Jacobsohn, L.G. [Center for Optical Materials Science and Engineering Technologies (COMSET), and School of Materials Science and Engineering, Clemson University, Clemson, SC (United States); Blair, M.W. [Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

2013-01-15

This paper presents an overview of a systematic study to develop new thermoluminescence (TL) and optically stimulated luminescence (OSL) materials using solution combustion synthesis (SCS) for applications such as personal OSL dosimetry, 2D dose mapping, and temperature sensing. A discussion on the material requirements for these applications is included. We present X-ray diffraction (XRD) data on single phase materials obtained with SCS, as well as radioluminescence (RL), TL and OSL data of lanthanide-doped materials. The results demonstrate the possibility of producing TL and OSL materials with sensitivity similar to or approaching those of commercial TL and OSL materials used in dosimetry (e.g., LiF:Mg,Ti and Al{sub 2}O{sub 3}:C) using SCS. The results also show that the luminescence properties can be improved by Li co-doping and annealing. The presence of an atypical TL background and anomalous fading are discussed and deserve attention in future investigations. We hope that these preliminary results on the use of SCS for production of TL and OSL materials are helpful to guide future efforts towards the development of new luminescence materials for different applications. - Highlights: Black-Right-Pointing-Pointer TL and OSL material produced with sensitivity similar to commercial materials. Black-Right-Pointing-Pointer Luminescence properties improved by Li co-doping and annealing. Black-Right-Pointing-Pointer The presence of atypical TL background and anomalous fading observed.

Thermoluminescence study of Mn doped lithium tetraborate powder and pellet samples synthesized by solution combustion synthesis

International Nuclear Information System (INIS)

Ozdemir, A.; Yegingil, Z.; Nur, N.; Kurt, K.; Tuken, T.; Depci, T.; Tansug, G.; Altunal, V.; Guckan, V.; Sigircik, G.; Yu, Y.; Karatasli, M.; Dolek, Y.

2016-01-01

In this paper, the thermoluminescence (TL) dosimetric characteristics under beta-ray, x-ray and gamma-ray excitations of powder and pellet Mn-doped lithium tetraborates (LTB) which were produced by solution combustion synthesis technique were investigated, and the results were compared with that of TLD-100 chips. The chemical composition and morphologies of the obtained LTB and Mn-doped LTB (LTB:Mn) were confirmed by X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) and scanning electron microscopy (SEM) with EDX. LTB:Mn was studied using luminescence spectroscopy. In addition, the effects of sintering and annealing temperatures and times on the thermoluminescence (TL) properties of LTB:Mn were investigated. The glow curves of powder samples as well as pellet samples exposed to different beta doses exhibited a low temperature peak at about 100 °C followed by an intense principal high temperature peak at about 260 °C. The kinetic parameters (E, b, s) associated with the prominent glow peaks were estimated using T m –T stop , initial rise (IR) and computerized glow curve deconvolution (CGCD) methods. The TL response of integral TL output increased linearly with increasing the dose in the range of 0.1–10 Gy and was followed by a superlinearity up to 100 Gy both for powder and pellet samples using beta-rays. Powder and pellet LTB:Mn were irradiated to a known dose by a linear accelerator with 6 and 18 MV photon beams, 6–15 MeV electron beams and a traceable 137 Cs beam to investigate energy response. Further, TL sensitivity, fading properties and recycling effects related with beta exposure of LTB:Mn phosphor were evaluated and its relative energy response was also compared with that of TLD-100 chips. The comparison of the results showed that the obtained phosphors have good TL dose response with adequate sensitivity and linearity for the measurement of medical doses.

Personnel radiation monitoring by thermoluminescence dosimetry (1995-96)

International Nuclear Information System (INIS)

Daw Mi Cho Cho; Daw Yi Yi Khin; Daw San San; U Maung Maung Tin; Daw Hla Hla Win

2001-01-01

Personnel radiation monitoring which is the dose assessment of individual doses from external radiation received by radiation workers has been carried out by Thermoluminescence Dosimetry system consisting of a Vinten Toledo TLD reader, LiF dosimeters and associated equipment. The exposed TLD dosimeters were measured by TLD reader and the dose evaluation and dose registration were done on personal computer. Due to the records of 1995-96, most of the radiation workers complied with the permissible dose recommended by IAEA and ICRP 60. (author)

Dating pleistocene fossil coastal sand dunes by thermoluminescence

International Nuclear Information System (INIS)

Poupeau, G.; Souza, J.H.; Soliani Junior, E.; Loss, E.L.

1983-01-01

It was shown recently that sunlight exposure is able to bleach most of the geological thermoluminescence (TL) of wind transported sediments. This property has been used in an attempt to date dunes from the well developed recent quaternary coastal dunes system of Rio Grande do Sul. Preliminary results presented here, show that TL dating on fossil sand dunes from Rio Grande do Sul should be possible in a time range from present to at least 50.000 yr and possibly more than 100.000 yr. (Author) [pt

Method of making isodose curve using thermoluminescence dosemeter

International Nuclear Information System (INIS)

Bakar Ramain, A.

1975-01-01

Line source of 60 Co in the form of needles and tubes are extensively used in radiotherapy in moulds, implants, and intracavitary techniques for the treatment of malignant lesions. It is important to have isodose distributions in tissue for those source for purposes of treatment planning. The isodose distributions have been obtained experimentally by using tinny lithium-fluoride (Lsub(i)F) thermoluminescent dosemeters (TLD) and they are compared to the theoretical results. The distinct advantages of Lsub(i)F (TLD) in such measurements are briefly discussed. (author)

Thermoluminescence of films of metal oxides and its application to the low energy ionizing radiation dosimetry; Termoluminiscencia de peliculas de oxidos metalicos y su aplicacion a la dosimetria de la radiacion ionizante de baja energia

Energy Technology Data Exchange (ETDEWEB)

Azorin N, J.; Rivera M, T.; Furetta, C. [Departamento de Fisica, Universidad Autonoma Metropolitana-Iztapalapa, 09000 Mexico D.F. (Mexico); Falcony G, C. [Departamento de Fisica, Centro de Investigacion y Estudios Avanzados, IPN, 07000 Mexico D.F. (Mexico); Martinez S, E.; Garcia H, M. [Instituto de Investigaciones en Materiales, UNAM, 04510 Mexico D.F. (Mexico)

2002-07-01

The obtained results from 1997 to date in the project {sup S}tudy of the thermoluminescence of metal oxides and their application to the ionizing radiation as regards to the development of ZrO{sub 2} and of Al{sub 2}O{sub 3} doped and without doped films with rare earths are presented. The obtained results irradiating ZrO{sub 2} and of Al{sub 2}O{sub 3} films with ultraviolet light and visible light have been satisfactory; whereas these materials have resulted promising to measure beta particles, X-rays and low energy gamma rays. (Author)

Quantitative carbon-14 autoradiography at the cellular level: principles and application for cell kinetic studies

International Nuclear Information System (INIS)

Doermer, P.

1981-01-01

Amounts of radio-labelled substances as low as 10 -18 moles incorporated into individual cells can be measured by utilizing techniques of quantitative autoradiography. The principles and application of quantitative carbon-14 autoradiography are reviewed. Silver grain densities can be counted by automated microphotometry allowing on-line data processing by an interfaced computer. Rate measurements of 14 C-thymidine incorporation into individual cells yield values of the DNA synthesis rate and the DNA synthesis time of a cell compartment can be derived. This is an essential time parameter for the evaluation of kinetic events in proliferating cell populations. This method is applicable to human cells without radiation hazard to man and provides an optimal source of detailed information on the kinetics of normal and diseased human haematopoiesis. Examples of application consist of thalassaemia, malaria infection, iron deficiency anaemia and acute myelogenous leukaemia. (author)

Obtention of thermoluminescent efficiencies by means of irradiation of TLD-100 dosemeters with proton beams helium and carbon

International Nuclear Information System (INIS)

Avila, O.; Rodriguez V, M.; Aviles, P.; Gamboa de Buen, I.; Buenfil, A.E.; Ruiz T, C.; Brandan, M.E.

2002-01-01

In this work, the advances of a serial of measurements of relative efficiency thermoluminescent of heavy charged particles (PCP) with respect to gamma radiation for TLD-100, dosemeters of LiF: Mg,Ti manufactured by the Harshaw-Bicron company are reported. The PCP are essentials in the implementation of dosimetry associated with medical applications. The measurements before gamma radiation were carrying out using the Vickrad irradiator of the National Institute of Nuclear Research at dose of 1.663 Gy. The measures which are reported about protons, helium and carbon were realized using the Pelletron accelerator of the Physics Institute of the UNAM. (Author)

Activation energies from blue- and red-thermoluminescence (TL) of quartz grains and mean lives of trapped electrons related to natural red-TL

International Nuclear Information System (INIS)

Hashimoto, T.; Kojima, M.; Shirai, N.; Ichino, M.

1993-01-01

A three-dimensional representation of thermoluminescence (TL) spectra has been established by employing an image intensifier unit combined with a simple spectrophotometer and a microcomputer. By means of this TL spectrometric system, natural quartz grains could be distinguished as either blue-and/or red-TL ones. In these blue- and red-TL wavelength regions, activation energies from artificially irradiated quartz grains are evaluated using a repeated initial rise method. An apparent difference of activation energies in the two colorations was observed for dune sands presumably originating from different quartz sources. On the other hand, quartz grains extracted from a volcanic ash sediment showed completely similar activation energies in both TL color regions over all temperatures. Subsequently, the kinetic parameters were derived for the naturally occurring red-TL, possessing an apparent single peak around 340 o C, from volcanically originating quartz grains by fitting a theoretical equation to the glow curves, after evaluating activation energies. On the basis of the empirical kinetic parameters, the mean life of trapped electrons relating to a main 340 o C peak has been proved to be 1 million years, and a secondary weak peak around 280 o C in the natural red-TL glow curve has been confirmed. (author)

Thermoluminescence properties of Mn-doped CaYAl3O7 phosphor irradiated with ultra-violet, mega-voltage and gamma radiation

International Nuclear Information System (INIS)

Pathak, Pushpraj; Selot, Anupam; Kurchania, Rajnish

2014-01-01

Low temperature combustion synthesis was employed for the preparation of CaYAl 3 O 7 (Mn 2+ ) phosphor. X-Ray diffraction (XRD) patterns were recorded to confirm the phase formation. Estimated particle size was found to be ∼19.9 nm by using the Debye Scherrer's formula. FTIR study confirms the formation of CaYAl 3 O 7 compound, escape of nitrates and other organic products. Thermoluminescence (TL) glow curves of the prepared phosphor were recorded after exposing the sample with Ultra-violet (UV), 6-Mega-voltage (MV), 16-MV and Co-60(Cobalt-60, 1.25-MeV average gamma energy) radiation. Trapping parameters namely activation energy (E), order of kinetics (b) and frequency factor(s) of main peak, centered around 186 °C in the sample irradiated with UV source for 20 min, were determined using glow curve shape (Chen's) method. It has been observed that the TL peak intensity increases with increasing the exposure from UV source. Also with increases the energy of incident radiation a decrease in TL peak intensity were observed. This could be due to higher penetration power and less absorbance of incident beam in the phosphor material. Analysis suggests that possibility of utilizing this phosphor in futuristic low and high energy dosimetric applications as well as in solid state lighting devices. - Highlights: • The average particle size was found to be 19.9 nm of CaYAl 3 O 7 :Mn 2+ phosphor synthesized by the combustion method. • Two glow peaks were recorded in UV exposed sample. However with Gamma and MV irradiated sample a single glow peak was observed. • TL intensity in the sample irradiated with UV is higher as compared to Gamma and MV. • Glow peaks of the phosphor obeys second order kinetic has 0.637 eV activation energy and 9.9×10 7 S −1 frequency factor. • Useful in radiation dosimetry as well as solid state lighting

Development of Mg B4 O7:Dy thermoluminescent solid dosemeter for using on the thermal neutron dosimetry

International Nuclear Information System (INIS)

Potiens Junior, A.J.; Campos, L.L.; Todo, A.S.

1992-01-01

The magnesium tetraborate doped with dysprosium (Mg B 4 O 7 :O y ) thermoluminescent phosphor is developed, containing boron, which boron 10 isotope has high cross section for thermal neutrons by 10 B (n,α) 7 Li reaction. The nitric acid concentration, the number of washing for removing the excess of boric acid, the powder granulation of Mg B 4 O 7 :O y , the percentage of teflon used as binder and the reproducibility of thermoluminescent answer are also presented. (C.G.C.)

Personnel radiation dosimetry laboratory accreditation programme for thermoluminescent dosimeters : a proposal

International Nuclear Information System (INIS)

Bhatt, B.C.; Srivastava, J.K.; Iyer, P.S.; Venkatraman, G.

1993-01-01

Accreditation for thermoluminescent dosimeters is the process of evaluating a programme intending to use TL personnel dosimeters to measure, report and record dose equivalents received by radiation workers. In order to test the technical competence for conducting personnel dosimetry service as well as to decentralize personnel monitoring service, it has been proposed by Radiological Physics Division (RPhD) to accredit some of the laboratories, in the country. The objectives of this accreditation programme are: (i) to give recognition to competent dosimetry processors, and (ii) to provide periodic evaluation of dosimetry processors, including review of internal quality assurance programme to improve the quality of personnel dosimetry processing. The scientific support for the accreditation programme will be provided by the scientific staff from Radiological Physics Division (RPhD) and Radiation Protection Services Division (RPSD). This paper describes operational and technical requirements for the Personnel Radiation Dosimetry Laboratory Accreditation Programme for Thermoluminescent Dosimeters for Personnel Dosimetry Processors. Besides, many technical documents dealing with the TL Personnel Dosimeter System have been prepared. (author). 5 refs., 2 figs

A thermoluminescence study of vempalle dolomites and its depositional environments

International Nuclear Information System (INIS)

Bhattacharya, A.K.; Rao, C.N.; Kaul, I.K.

1976-01-01

An attempt has been made to interpret the depositional environment of Vempalle dolomites (India) by thermoluminescence method. It has been demonstrated that glow curve patterns reflect the environmental condition of deposition for carbonate sediments. The glow curves were obtained for natural samples as well as samples irradiated by Co 60 and compared. A majority of the samples were concluded to be diagenetic. (A.K.)

Thermoluminescence study of aluminium oxide doped germanium prepared by combustion synthesis method

Directory of Open Access Journals (Sweden)

Saharin Nurul Syazlin Binti

2017-01-01

Full Text Available The present paper reports the optimum concentration of germanium (Ge dopant in aluminium oxide (AhO3 samples prepared by combustion synthesis (CS method for thermoluminescence (TL studies. The samples were prepared at various Ge concentration i.e. 1 to 5% mol. The phase formation of un-doped and Ge-doped Al2O3 samples was determined using X-ray Diffraction (XRD. The sharp peaks present in the XRD pattern confirms the crystallinity of the samples. The samples were then exposed to 50 Gy Cobalt-60 sources (Gamma cell 220. TL glow curves were measured and recorded using a Harshaw Model 3500 TLD reader. Comparison of TL peaks were observed to obtain the best composition of Ge dopants. A simple glow curves TL peak at around 175̊C for all composition samples was observed. It was also found that the composition of aluminium oxide doped with 3.0% of germanium exhibits the highest thermoluminescence (TL intensity which is 349747.04 (a.u.

Measurement of thermoluminescence - a new method for detecting radiation treatment of spices. Die Messung der Thermolumineszenz - ein neues Verfahren zur Identifizierung strahlenbehandelter Gewuerze

Energy Technology Data Exchange (ETDEWEB)

Heide, L; Boegl, W

1984-12-01

By the experiments described in this report it was examined in 14 different spices to which extent measurements of thermoluminescence intensity of up to 300/sup 0/C are suitable for detecting treatment with ionizing radiation. The optimal weight of each spice was first determined for a later investigation of the dependence of thermoluminescence intensity on dose and postirradiation storage. In most spices, radiation treatment is detectable as long as after a storage period of over 2 months. In general it may be stated that thermoluminescence measurement is a reliable method for detecting radiation treatment in supplement to chemiluminescence measurement.

The influence of radiation-induced defects on thermoluminescence and optically stimulated luminescence of α-Al{sub 2}O{sub 3}:C

Energy Technology Data Exchange (ETDEWEB)

Nyirenda, A.N., E-mail: anyirenda@gmail.com; Chithambo, M.L.

2017-04-15

It is known that when α-Al{sub 2}O{sub 3}:C is exposed to excessive amounts of ionising radiation, defects are induced within its matrix. We report the influence of radiation-induced defects on the thermoluminescence (TL) and optically stimulated luminescence (OSL) measured from α-Al{sub 2}O{sub 3}:C after irradiation to 1000 Gy. These radiation-induced defects are thermally unstable in the region 450–650 °C and result in TL peaks in this range when the TL is measured at 1 °C/s. Heating a sample to 700 °C obliterates the radiation-induced defects, that is, the TL peaks corresponding to the radiation induced defects are no longer observed in the subsequent TL measurements when moderate irradiation doses below 10 Gy are used. The charge traps associated with these radiation-induced defects are more stable than the dosimetric trap when the sample is exposed to either sunlight or 470-nm blue light from LEDs. TL glow curves measured following the defect-inducing irradiation produce a dosimetric peak that is broader and positioned at a higher temperature than observed in glow curves obtained before the heavy irradiation. In addition, sample sensitization/desensitization occurs due to the presence of these radiation-induced defects. Furthermore, both the activation energy and the kinetic order of the dosimetric peak evaluated when the radiation-induced defects are present in the sample are significantly lower in value than those obtained when these defects are absent. The radiation-induced defects also affect the shape and total light sum of the OSL signal as well as the position and width of the resultant residual phototransferred thermoluminescence main peak.

Thermoluminescent dosemeter in a X-ray diffractometer; Dosimetria termoluminiscente en un difractometro de rayos X

Energy Technology Data Exchange (ETDEWEB)

Mendoza A, D.; Gonzalez M, P.; Falcon B, T. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, Mexico D.F. (Mexico); Castano, V.M. [Instituto de Fisica, UNAM, Laboratorio Juriquilla, A.P. 1-1010, C.P. 76001, Queretaro (Mexico)

1999-07-01

In this work it was presented the results obtained of the dosimetry which was realized in a X-ray diffractometer for powders, trademark Siemens D5000, using the thermoluminescent signal generated by the X-rays in the commercial dosemeter TLD-100 of Harshaw, US. In according to the results obtained, the radiation quantity received by an analysed material in the diffractometer, will be proportional to exposure time and it can vary from unities until tenths of grays. These results are very outstanding when are analysed crystalline materials in a diffractometer, for knowing the present crystalline phases, mainly if these are highly sensitive to the ionizing radiation, as it is the case of the thermoluminescent materials. (Author)

Focuss algorithm application in kinetic compartment modeling for PET tracer

International Nuclear Information System (INIS)

Huang Xinrui; Bao Shanglian

2004-01-01

Molecular imaging is in the process of becoming. Its application mostly depends on the molecular discovery process of imaging probes and drugs, from the mouse to the patient, from research to clinical practice. Positron emission tomography (PET) can non-invasively monitor . pharmacokinetic and functional processes of drugs in intact organisms at tracer concentrations by kinetic modeling. It has been known that for all biological systems, linear or nonlinear, if the system is injected by a tracer in a steady state, the distribution of the tracer follows the kinetics of a linear compartmental system, which has sums of exponential solutions. Based on the general compartmental description of the tracer's fate in vivo, we presented a novel kinetic modeling approach for the quantification of in vivo tracer studies with dynamic positron emission tomography (PET), which can determine a parsimonious model consisting with the measured data. This kinetic modeling technique allows for estimation of parametric images from a voxel based analysis and requires no a priori decision about the tracer's fate in vivo, instead determining the most appropriate model from the information contained within the kinetic data. Choosing a set of exponential functions, convolved with the plasma input function, as basis functions, the time activity curve of a region or a pixel can be written as a linear combination of the basis functions with corresponding coefficients. The number of non-zero coefficients returned corresponds to the model order which is related to the number of tissue compartments. The system macro parameters are simply determined using the focal underdetermined system solver (FOCUSS) algorithm. The FOCUSS algorithm is a nonparametric algorithm for finding localized energy solutions from limited data and is a recursive linear estimation procedure. FOCUSS algorithm usually converges very fast, so demands a few iterations. The effectiveness is verified by simulation and clinical

Dosimetry of accidents using thermoluminescence of dental restorative porcelains

International Nuclear Information System (INIS)

Mauricio, C.L.P.; Rosa, L.A.R. da; Cunha, P.G. da

1986-01-01

The thermoluminescence (TL) properties of dental restorative porcelain were investigated with the aim of using this material as a TL dosemeter to estimate high doses in radiological accidents. The irradiations were carried out with a 60 Co gamma source and X rays with effective energies from 29 to 95 KeV. The samples have a limit of detection at about 50R and their reproducibility is better than 15%. Linearity was observed from 50 to 5000R. (Author) [pt

The Application of Biomimicry in Kinetic Facades

Directory of Open Access Journals (Sweden)

Wijdan Deyaa Abdul Jalil

2016-10-01

Full Text Available Biomimicry, as a way of thinking to go back to nature for inspiration, has its impact on many contemporary technological achievements. Some of them are used to design and construct kinetic facades in architecture, because of the importance role of facades in reducing sun radiation, that enter the building through using shading systems and components. In light of this, research problem is determined: "Do technologies which are inspired by biomimicry effect shading in kinetic facades through its characteristics in materials and the mechanics. So the research identifies its goal as: "To identify the types of kinetic facades in buildings and their characteristics as materials and shading mechanism associated with the biomimicry. The research explains the basic types of kinetic facades depending on the technology and materials used to provide the possibility of reducing solar radiation that enters the building. It also compares the case studies which have been chosen in their inspiration concept from biological world, which reflect on the system used of protecting against sun and reducing energy consumption as the designer teams suggest. The research concluded that kinetic façade which is depending on smart materials is self-responding and don't need energy to operate, so it is better in reducing consumption of energy.

Dosimetric behavior of thermoluminescent dosimeters at low doses in diagnostic radiology; Comportamiento dosimetrico de dosimetros termoluminiscentes a bajas dosis en radiodiagnostico

Energy Technology Data Exchange (ETDEWEB)

Del Sol F, S.; Garcia S, R.; Guzman M, J.; Sanchez G, D.; Rivera M, T. [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Av. Legaria 694, Col. Irrigacion, 11500 Mexico D. F. (Mexico); Ramirez R, G. [Hospital Juarez de Mexico, Av. IPN 5160, Col. Magdalena de las Salinas, 07760 Mexico D. F. (Mexico); Gaona, E., E-mail: susi2489@hotmail.com [Universidad Autonoma Metropolitana, Unidad Xochimilco, Calz. del Hueso 1100, Col. Villa Quietud, 04960 Mexico D. F. (Mexico)

2015-10-15

Thermoluminescent (Tl) characteristics of TLD-100, LiF:Mg,Cu,P, and CaSO{sub 4}: Dy the under homogeneous field of X-ray beams of diagnostic irradiation and its verification using thermoluminescent dosimetry is presented. The irradiations were performed utilizing an X-ray beam generated by a Radiology Mexican Company: MRH-II E GMX 325-AF SBV-1 model, with Rotating Anode X-Ray Tube installed in the Hospital Juarez Norte de Mexico in Mexico City. Different thermoluminescent characteristics of dosimetric material were studied, such as, batch homogeneity, Tl glow curve, Tl response as a function of X-ray dose, reproducibility and fading. Materials were calibrated in terms of absorbed dose to the standard calibration distance and positioned in a generic Phantom was used. Dose verification and comparison with the measurements made with that obtained by TLD-100 were analyzed. Preliminary results indicate the dosimetric peak appears at 243, 236 and 277 ± 5 degrees C respectively, these peaks are in agreement with that reported in the literature. Tl glow curve as a function of X-ray dose showed a linearity in the range from 1.76 mGy up to 14.70 mGy for all materials. Fading for a period of one month at room temperature showed low fading LiF:Mg,Cu,P, medium and high for TLD-100 and CaSO{sub 4}: Dy. The results suggest that the three materials are suitable for measurements at low doses in radiodiagnostic, however, for its dosimetric characteristics are most effective for individual applications: personal dosimetry and monitors limb (LiF:Mg,Cu,P), clinical dosimetry and environmental (TLD-100 and CaSO{sub 4}: Dy). (Author)

Dose profile measurement in computerized axial tomography equipment using thermoluminescent dosemeters

International Nuclear Information System (INIS)

Azorin V, J.C.; Falcony, C.; Azorin N, J.

2000-01-01

In this work are presented the results about measuring the radiation dose profile in two equipment of computerized axial tomography (Tac). Thermoluminescent dosemeters (Dtl) of LiF, Mg, Cu, P + Ptfe in form of disks were used which were developed and made in Mexico. The results showed that Dtl are appropriated for these type of studies. (Author)

NRC TLD [thermoluminescent dosimeter] Direct Radiation Monitoring Network: Progress report, January-March 1988

International Nuclear Information System (INIS)

Struckmeyer, R.; McNamara, N.

1988-06-01

This report provides the status and results of the NRC Thermoluminescent Dosimeter (TLD) Direct Radiation Monitoring Network. It presents the radiation levels measured in the vicinity of NRC licensed facility sites throughout the country for the first quarter of 1988

Comparative analysis of dose rates in bricks determined by neutron activation analysis, alpha counting and X-ray fluorescence analysis for the thermoluminescence fine grain dating method

Czech Academy of Sciences Publication Activity Database

Bártová, H.; Kučera, Jan; Musílek, L.; Trojek, T.

2014-01-01

Roč. 104, NOV (2014), s. 393-397 ISSN 0969-806X. [1st International Conference on Dosimetry and its Applications (ICDA). Prague, 23.6.2013-28.6.2013] R&D Projects: GA MŠk(XE) LM2011019 Institutional support: RVO:61389005 Keywords : Alpha coutning * neutron activation analysis * X-ray fluorescence * thermoluminescence dating * dose rate Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 1.380, year: 2014

Thermoluminescent dosimetry of beta radiations of 90 Sr/ 90 Y using amorphous ZrO2

International Nuclear Information System (INIS)

Rivera M, T.; Olvera T, L.; Azorin N, J.; Barrera R, M.; Soto E, A.M.

2005-01-01

In this work the results of studying the thermoluminescent properties (Tl) of the zirconium oxide in its amorphous state (ZrO 2 -a) before beta radiations of 90 Sr/ 90 Y are presented. The amorphous powders of the zirconium oxide were synthesized by means of the sol-gel technique. The sol-gel process using alkoxides like precursors, is an efficient method to prepare a matrix of zirconium oxide by hydrolysis - condensation of the precursor to form chains of Zr-H 3 and Zr-O 2 . One of the advantages of this technique is the obtention of gels at low temperatures with very high purity and homogeneity. The powders were characterized by means of thermal analysis and by X-ray diffraction. The powders of ZrO 2 -a, previously irradiated with beta particles of 90 Sr/ 90 Y, presented a thermoluminescent curve with two peaks at 150 and 257 C. The dissipation of the information of the one ZrO 2 -a was of 40% the first 2 hours remaining constant the information for the following 30 days. The reproducibility of the information was of ± 2.5% in standard deviation. The studied characteristics allow to propose to the amorphous zirconium oxide as thermoluminescent dosemeter for the detection of beta radiation. (Author)

Thermoluminescent dosimetry of beta radiations of 90 Sr/ 90 Y using ZrO2: Eu

International Nuclear Information System (INIS)

Olvera T, L.; Azorin N, J.; Barrera S, M.; Soto E, A.M.; Rivera M, T.

2005-01-01

In this work the results of studying the thermoluminescent properties (TL) of the doped zirconium oxide with europium (ZrO 2 : Eu 3+ ) before beta radiations of 90 Sr/ 90 Y are presented. The powders of ZrO 2 : Eu 3+ were obtained by means of the sol-gel technique and they were characterized by means of thermal analysis and by X-ray diffraction. The powders of ZrO 2 : Eu 3+ , previously irradiated with beta particles of 90 Sr/ 90 Y, presented a thermoluminescent curve with two peaks at 204 and 292 C respectively. The TL response of the ZrO 2 : Eu 3+ as function of the absorbed dose was lineal from 2 Gy up to 90 Gy. The fading of the information of the ZrO 2 : Eu 3+ was of 10% the first 2 hours remaining almost constant the information by the following 30 days. The ZrO 2 doped with the (Eu 3+ ) ion it was found more sensitive to the beta radiation that the one of zirconium oxide without doping (ZrO 2 ) obtained by the same method. Those studied characteristics allow to propose to the doped zirconium oxide with europium like thermoluminescent dosemeter for the detection of the beta radiation. (Author)

Thermoluminescence characterization of isolated minerals to identify oranges exposed to γ-ray, e-beam, and X-ray for quarantine applications

International Nuclear Information System (INIS)

Deokjo Jo; Joong-Ho Kwon; Bhaskar Sanyal; Bhabha Atomic Research Centre, Mumbai; Ju-Woon Lee

2015-01-01

Identification of irradiated fruits is of paramount importance to address the limitation of irradiation technology because of varying national and international regulations. Thermoluminescence (TL) analysis was carried out to identify oranges irradiated with γ-ray, electron beam and X-ray. Non-irradiated samples exhibited background TL signals, but all the irradiated samples showed defined TL glow curves characterized by a prominent peak at 158-163 deg C. Characterizations of the irradiated standard minerals showed that feldspars were the major contributors to the TL emission and stable TL signals revealed a successful detection of irradiated oranges even after a prolonged storage. (author)

Energy absorption buildup factors for thermoluminescent dosimetric materials and their tissue equivalence

DEFF Research Database (Denmark)

Manohara, S.R.; Hanagodimath, S.M.; Gerward, Leif

2010-01-01

Gamma ray energy-absorption buildup factors were computed using the five-parameter geometric progression (G-P) fitting formula for seven thermoluminescent dosimetric (TLD) materials in the energy range 0.015-15 MeV, and for penetration depths up to 40 mfp (mean free path). The generated energy-absorption...

Thermoluminescence of pure LiF and Lif (TLD-100) irradiated at room temperature; Termoluminiscencia en LiF puro y LiF dosimetrico (TLD-100), irradiados a temperatura ambiente

Energy Technology Data Exchange (ETDEWEB)

Sagastibelza Chivite, F

1980-07-01

The thermoluminescence of pure LiF and LiF (TLD-100) crystals irradiated at room temperature with x - or gamma-rays has been studied up to 460 degree centigree. For most of the glow peaks found the kinetics, preexponential factors and activation energies have been determined. These parameters have been obtained by means of the isothermal method. The study of the thermal annealing of the radiation induced F and Z centres has allow to show that there is a correlation among the glow peaks and the annealing stages of these centres. It is concluded that the F and Z - centres play the role of recombination centres for halogen interstitial atom thermally released from traps. Light emission occurs in this recombination. (Author) 120 refs.

Dosimetric and thermoluminescent characteristics of sintered samples based on Li{sub 2}OAl{sub 2}O{sub 3}nSiO{sub 2} systems

Energy Technology Data Exchange (ETDEWEB)

Cogollo P, R.; Salcedo Q, J. [Universidad de Cordoba, Materials and Applied Physics Group, Carrera 6 No. 76-103, Monteria, Cordoba (Colombia); Gutierrez F, O., E-mail: rafaelcogollo@correo.unicordoba.edu.co [Metropolitan Technological Institute, Alquimia Group, Calle 54 No. 30-01, Medellin (Colombia)

2013-10-01

This work describes the thermoluminescent (Tl) characteristics of lithium aluminosilicates, Li{sub 2}OAl{sub 2}O{sub 3}nSiO{sub 2}, for its possible use as Tl dosimeter for low doses. The sinterized tablets of Li{sub 2}OAl{sub 2}O{sub 3}nSiO{sub 2} were characterized by means of X-ray diffraction (XRD), and irradiated at different doses using a Theratron 780 C-{sup 60}Co unit in air at room temperature. The Rasheedy's technique was used for the kinetic trap parameters determination. The XRD results show a mixture of two phases of 64% {beta}-spodumene and 36% {beta}-eucryptite in the sinterized tablets. Tl analysis indicates that in these systems, recombination processes prevail, and that these systems can be used successfully as Tl dosimeters for therapeutic dose ranges. (Author)

Thermoluminescence of Zn O thin films deposited by chemical bath; Termoluminiscencia de peliculas delgadas de ZnO depositadas por bano quimico

Energy Technology Data Exchange (ETDEWEB)

Camacho A, M. C.; Cruz V, C. [Universidad de Sonora, Departamento de Investigacion en Polimeros y Materiales, Apdo. Postal 130, 83000 Hermosillo, Sonora (Mexico); Bernal H, R.; Berman M, D. [Universidad de Sonora, Departamento de Investigacion en Fisica, Apdo. Postal 5-088, 83190 Hermosillo, Sonora (Mexico); Castano M, V. M., E-mail: carmencamacho@gimmunison.com [UNAM, Instituto de Fisica, Centro de Fisica Aplicada y Tecnologia Avanzada, Apdo. Postal 1-1010, 76000 Queretaro, Qro. (Mexico)

2015-10-15

Full text: Zn O films on Si were synthesized using a deposition method by chemical bath and thermally treated at 900 degrees C for 12 h in air. The morphological characterization by scanning electron microscopy reveals that uniform films were obtained. To investigate the thermoluminescent properties of the films were exposed to irradiation with beta particles with doses in the range from 0.5 to 128 Gy. The brightness curves obtained using a heating rate of 5 degrees C have two peaks, one at 124 and another at 270 degrees C, and a linear dependence of the integrated thermoluminescence as a function of dose. The second maximum reveals the existence of localized trapping states of potential utility in thermoluminescent dosimetry. (Author)

Thermal quenching of thermoluminescence in quartz samples of various origin

International Nuclear Information System (INIS)

Subedi, B.; Oniya, E.; Polymeris, G.S.; Afouxenidis, D.; Tsirliganis, N.C.; Kitis, G.

2011-01-01

The effect of thermal quenching stands among the most important properties in the thermoluminescence (TL) of quartz on which many applications of TL are based. Since the quartz samples used in various applications are all of different origin it is useful to investigate whether the values of the thermal quenching parameters, i.e. the activation energy for thermal quenching W and a parameter C which describes the ratio of non-radiative to radiative luminescence transitions, evaluated mainly in specific quartz samples can be extrapolated to quartz samples of unknown origin as well as to quartz samples which are annealed at high temperatures. In the present work the TL glow curve of a series of un-annealed and annealed natural and synthetic quartz samples were studied as a function of the heating rate between 0.25 K/s and 16 K/s. Using an indirect fitting method it was found that the thermal quenching parameters W and C in most of the quartz samples are very similar to the values accepted in the literature. Furthermore, in some cases the thermal quenching parameters W and C are not the same for all TL glow-peaks in the same glow-curve. Finally, the strong external treatment of annealing the quartz samples at very high temperature can also influence at least one of the thermal quenching parameters.

Extracting surface diffusion coefficients from batch adsorption measurement data: application of the classic Langmuir kinetics model.

Science.gov (United States)

Chu, Khim Hoong

2017-11-09

Surface diffusion coefficients may be estimated by fitting solutions of a diffusion model to batch kinetic data. For non-linear systems, a numerical solution of the diffusion model's governing equations is generally required. We report here the application of the classic Langmuir kinetics model to extract surface diffusion coefficients from batch kinetic data. The use of the Langmuir kinetics model in lieu of the conventional surface diffusion model allows derivation of an analytical expression. The parameter estimation procedure requires determining the Langmuir rate coefficient from which the pertinent surface diffusion coefficient is calculated. Surface diffusion coefficients within the 10 -9 to 10 -6  cm 2 /s range obtained by fitting the Langmuir kinetics model to experimental kinetic data taken from the literature are found to be consistent with the corresponding values obtained from the traditional surface diffusion model. The virtue of this simplified parameter estimation method is that it reduces the computational complexity as the analytical expression involves only an algebraic equation in closed form which is easily evaluated by spreadsheet computation.

A comparative thermoluminescence and electron spin resonance study of synthetic carbonated A-type hydroxyapatite

International Nuclear Information System (INIS)

Oliveira, L.C.; Rossi, A.M.; Baffa, O.

2012-01-01

Intensity of the 150 °C thermoluminescence peak of beta-irradiated carbonated synthetic A-type hydroxyapatite is approximately 12 times higher than that of the noncarbonated material. Deconvolution of the glow curve showed that this peak is a result of a trap distribution. An attempt was made to relate this thermoluminescence peak enhanced by carbonation with the ESR signal of the CO 2 − radical in natural or synthetic hydroxyapatite. - Highlights: ► Synthetic hydroxyapatite was carbonated with CO 2 . ► TL enhanced by 12 times in carbonated synthetic A-type hydroxyapatite. ► EPR and TL were performed to find out a relation between CO 2 − center and the TL. ► No direct relation was found between the CO 2 − center and TL enhancement.