scholarly journals Analysis of the thermoluminescent of borate glass by computerized glow curve deconvolution in kinetic formalism

2021 ◽  
Vol 2070 (1) ◽  
pp. 012009
Author(s):  
S. Nabadwip Singh
Keyword(s):  
Activation Energy ◽  
Glow Curve ◽  
Borate Glass ◽  
Frequency Factor ◽  
Activation Energies ◽  
Suitable Material ◽  
Order Of Kinetics ◽  
Thermoluminescence Dosimetry

Abstract Borate based phosphor is a suitable material for thermoluminescence dosimetry. Glow curves of β-irradiated pure borate glass has been analyzed by restoring to Computerized Glow Curve Deconvolution (CGCD) technique and evaluate the trapping parameters namely activation energy (E), frequency factor (s) and order of kinetics (b). It is observed that there are stable peaks in the range 110° to 150°C even to various extent of thermal cleaned ones also. The activation energies of the phosphor are in the range 0.898 to 1.325 eV and frequency factors are in the order of 1011 to 1013 s−1.

An Overview on Peak Shape Method for Thermoluminescence Glow Curve Analysis

2018 ◽  
pp. 26-52
Author(s):  
Sukhamoy Bhattacharyya ◽  
Partha Sarathi Majumdar
Keyword(s):  
Activation Energy ◽  
Glow Curve ◽  
Frequency Factor ◽  
Curve Analysis ◽  
Peak Shape ◽  
Order Of Kinetics ◽  
Symmetry Factor ◽  
Alternative Approach ◽  
General Order ◽  
Thermoluminescence Glow Curve

The shape of a thermoluminescence (TL) glow curve has fundamental importance for calculating the characteristic parameters of trap levels within the band gap. TL analysis are mostly based on the three-parameter general order kinetics model. The parameters are activation energy, order of kinetics, and frequency factor. Peak shape method is one of the most prominent methods for extracting the activation energy from a TL curve. An overview of different peak shape methods along with an alternative approach formulated directly from basic TL equations is presented in this chapter. Generally, peak shape method requires prior knowledge of order of kinetics to determine activation energy which creates a difficulty due to the non-uniqueness of symmetry factor for a particular value of order of kinetics. A modified version of peak shape method which is free from this constraint is discussed here. Activation energies from experimental curves of tremolite and actinolite are estimated using peak shape method. Limitation of peak shape method for saturated TL peaks with heavy retrapping is also discussed.

APPLICATION OF CVD DIAMOND FILMS FOR UV THERMOLUMINESCENCE DOSIMETER

2002 ◽  
Vol 16 (06n07) ◽  
pp. 1003-1007 ◽  
Author(s):  
J. AHN ◽  
B. GAN ◽  
Q. ZHANG ◽  
S. F. YOON ◽  
V. LIGATCHEV ◽  
...  
Keyword(s):  
Activation Energy ◽  
Glow Curve ◽  
Diamond Films ◽  
Frequency Factor ◽  
Cvd Diamond ◽  
Order Kinetic ◽  
First Order ◽  
Order Kinetic Model ◽  
Ionizing Radiations ◽  
Trap Activation

This study presents the investigation of CVD diamond for the application of an UV TL dosimeter. A 9-μm-thick film used in this study presents a TL glow curve with a well-defined first-order kinetic peak (at about 273 K), which norm ally presents in the glow curve from ionizing radiations, is not observed. By fitting the glow curve to a first-order kinetic model, the trap activation energy E t = 0.95 eV and frequency factor s = 5.6 x 106 s -1 have been resolved.

FADING CORRECTION OF NaCl(I) TLD

2006 ◽  
Vol 20 (09) ◽  
pp. 1077-1086
Author(s):  
B. ARUNKUMAR SHARMA ◽  
R. K. GARTIA ◽  
S. NABADWIP SINGH
Keyword(s):  
Activation Energy ◽  
Theoretical Prediction ◽  
Glow Curve ◽  
Thermal Activation ◽  
Room Temperature ◽  
Storage Period ◽  
Frequency Factor ◽  
Data Acquisition System ◽  
Thermal Activation Energy ◽  
State Of Art

The prediction of fading for the glow peaks relevant to dosimetry of iodised salt has been made using the values of the trapping parameters, namely the thermal activation energy (E), frequency factor (s) and the order of kinetic (b). This theoretical prediction has been checked with experimentally observed glow curves recorded after storage period of 2, 5, 10, 165, 375 and 790 days at room temperature (~21°C). Excellent agreement has been observed between the experimental and theoretical glow curves. This has been possible because of reliable retrieval of the trapping parameters by the use of Computerised Glow Curve Deconvolution (CGCD) as well as state-of-art of data acquisition system. The concept developed in the present paper in principle may be applied to any TLD.

Determination of ZrO2 Thermoluminescence Kinetic Parameters after UV Irradiation Using Peak Shape Methods

2005 ◽  
Vol 480-481 ◽  
pp. 381-386
Author(s):  
T. Rivera Montalvo ◽  
C. Furetta ◽  
J. Azorín Nieto ◽  
C. Falcony Guajardo ◽  
M. García ◽  
...  
Keyword(s):  
Glow Curve ◽  
Frequency Factor ◽  
Main Peak ◽  
Kinetics Parameters ◽  
Peak Intensity ◽  
Order Of Kinetics ◽  
Dosimetric Peak ◽  
Symmetry Properties ◽  
Good Agreement

Various experimental methods are currently employed for the determination of the trap parameters. Methods based on the glow curve shape extract information from a glow peak utilizing the temperature at the maximum emission, TM, the temperature on the ascending part of the peak ,T1, which corresponding to half peak intensity and the temperature on the descending part of the peak, T2, also corresponding to the half peak intensity; as well as, the half width parameters and the symmetry properties. In order to obtain the kinetic order b and the trap parameters, ZrO2 samples were exposed to 260 nm ultraviolet radiation (UVR). The trapping kinetics parameters of the ZrO2 dosimetric peak using the shape of the glow curve were then determined. The order of kinetics followed by the main peak was also determined using the same method. The values of activation energy E and frequency factor ,s, for the main peak of ZrO2 obtained by the above mentioned methods, showed a good agreement among them.

THE REACTIONS OF PERFLUOROETHYL RADICALS WITH HYDROGEN AND METHANE

1960 ◽  
Vol 38 (11) ◽  
pp. 2128-2135 ◽  
Author(s):  
S. J. W. Price ◽  
K. O. Kutschke
Keyword(s):  
Activation Energy ◽  
Hydrogen Abstraction ◽  
Frequency Factor ◽  
Activation Energies ◽  
Recombination Reaction ◽  
Limited Data ◽  
Kcal Mole ◽  
Fluorinated Radical

The reactions of C2F5 radicals, produced by the photolysis of (C2F5)2CO, with methane and hydrogen have been studied. Assuming zero activation energy for 2C2F5 → C4F10 the activation energies for C2F5 + CH4 → C2F5H + CH3 and C2F5 + H2 → C2F5H + H are 10.6 kcal/mole and 11.9 kcal/mole respectively. The present results have been correlated with data on the reactions of CF3, C3F7, and CH3 radicals with H2, D2, CH4, and C2H6. Taking Erecombination ≈ 0 in all cases and assuming the frequency factor for the recombination reaction varies little from radical to radical, the order of ease of hydrogen abstraction from a given substrate is CF3 > C2F5 > C3F7 > CH3. Similarly the ease of hydrogen abstraction from a substrate by a given fluorinated radical is C2H6 > H2 > CH4 > D2. A calculation based on very limited data indicates the reaction CH3 + C2F5COC2F5 → CH3COC2F5 + C2F5 may occur with an activation energy of approximately 7 kcal/mole.

scholarly journals Calculation of parameters for the model of an ideal phosphor

2016 ◽  
Vol 31 (2) ◽  
pp. 111-120 ◽  
Author(s):  
Zdravko Vejnovic ◽  
Milos Pavlovic ◽  
Pavle Hadzic ◽  
Milorad Davidovic
Keyword(s):  
Activation Energy ◽  
Kinetic Parameters ◽  
Glow Curve ◽  
Filling Factor ◽  
Frequency Factor ◽  
Physical Parameters ◽  
Calculation Of Parameters ◽  
Kinetics Order

Equations for the calculation of kinetic parameters of thermoluminescent processes are theoretically derived for a model of an ideal phosphor. The values used in the calculation are obtained from glow curves and the function that describes the normalized glow curve generated. On the basis of this function, the equations for activation energy, frequency factor, and retrapping factor, were derived. All expressions are valid for a general case, when the filling factor of traps is f0?1. The concept of kinetics order was used for the calculation of parameters and the parameter of kinetics order was defined by means of real physical parameters. Results obtained by the analysis of synthetic curves and experimental glow curves of phosphor materials provide a deeper understanding of thermoluminescent kinetics.

scholarly journals Coal Pyrolysis Distribution

2021 ◽  
Author(s):  
◽  
Sione Paea
Keyword(s):  
Activation Energy ◽  
Frequency Factor ◽  
Activation Energies ◽  
Energy Model ◽  
Smoothing Function ◽  
Coal Pyrolysis ◽  
Distributed Activation Energy Model ◽  
Constant Frequency ◽  
Underlying Distribution ◽  
First Order

<p>Coal pyrolysis is a complex process involving a large number of chemical reactions. The most accurate and up to date approach to modeling coal pyrolysis is to adopt the Distributed Activation Energy Model (DAEM) in which the reactions are assumed to consist of a set of irreversible first-order reactions that have different activation energies and a constant frequency factor. The differences in the activation energies have usually been represented by a Gaussian distribution. This thesis firstly compares the Simple First Order Reaction Model (SFOR) with the Distributed Activation Energy Model (DAEM), to explore why the DAEM may be a more appropriate approach to modeling coal pyrolysis. The second part of the thesis uses the inverse problem approach together with the smoothing function (iterative method) to provide an improved estimate of the underlying distribution in the wide distribution case of the DAEM. The present method significantly minimizes the error due to differencing and smoothes the chopped off parts on the underlying distribution curve.</p>

scholarly journals Coal Pyrolysis Distribution

2021 ◽  
Author(s):  
◽  
Sione Paea
Keyword(s):  
Activation Energy ◽  
Frequency Factor ◽  
Activation Energies ◽  
Energy Model ◽  
Smoothing Function ◽  
Coal Pyrolysis ◽  
Distributed Activation Energy Model ◽  
Constant Frequency ◽  
Underlying Distribution ◽  
First Order

<p>Coal pyrolysis is a complex process involving a large number of chemical reactions. The most accurate and up to date approach to modeling coal pyrolysis is to adopt the Distributed Activation Energy Model (DAEM) in which the reactions are assumed to consist of a set of irreversible first-order reactions that have different activation energies and a constant frequency factor. The differences in the activation energies have usually been represented by a Gaussian distribution. This thesis firstly compares the Simple First Order Reaction Model (SFOR) with the Distributed Activation Energy Model (DAEM), to explore why the DAEM may be a more appropriate approach to modeling coal pyrolysis. The second part of the thesis uses the inverse problem approach together with the smoothing function (iterative method) to provide an improved estimate of the underlying distribution in the wide distribution case of the DAEM. The present method significantly minimizes the error due to differencing and smoothes the chopped off parts on the underlying distribution curve.</p>

On temperature-dependent frequency factor in thermoluminescence measured with a hyperbolic heating profile

2001 ◽  
Vol 79 (9) ◽  
pp. 1133-1139 ◽  
Author(s):  
W S Singh ◽  
M Bhattacharya ◽  
S D Singh ◽  
P S Mazumdar
Keyword(s):  
Activation Energy ◽  
Temperature Dependence ◽  
Frequency Factor ◽  
Temperature Dependent ◽  
Order Of Kinetics ◽  
Dependent Frequency ◽  
Symmetry Factor ◽  
Heating Profile

In this paper, we investigate the consequences of the temperature dependence of the frequency factor on thermoluminescence peaks recorded in a hyperbolic heating profile. The temperature dependence of the frequency factor leads to nonuniqueness in the symmetry factor for a particular order of kinetics (b) and causes an error of the order of 5% in the determination of b and an error of the order of 10% in the determination of activation energy (E). PACS No.: 78.60Kn

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