Thermoluminescence of BaFCl_xBr_（1－x）：Sm System and Assignment of Their Glow Peaks

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Thermoluminescence Kinetic Parameters of TLD-600 and TLD-700 after 252Cf Neutron+Gamma and 90Sr-90Y Beta Radiations

The thermoluminescent(TL) properties such as glow curve structure, relative thermoluminescence sensitivity,dose response linearity of lithium fluoride thermoluminescent dosimeters 6 LiF:Ti,Mg(TLD-600) and 7 LiF:Ti,Mg(TLD-700) are investigated after irradiation ^(252)Cf neutron+gamma and ^(90)Sr-^(90)Y beta sources at room temperature and then the obtained results are compared. The kinetic parameters, namely the order of kinetics b,activation energy Ea and the frequency factor s,are calculated using the computerized glow curve deconvolution(CGCD) program. The effect of heating rate on the glow curves of dosimeters is also investigated. The maximum TL peak intensities and the total area under the glow curves decrease with the increasing heating rate. There is no agreement with the kinetic parameters calculated by the CGCD program for both radiation sources.

Thermoluminescence Energy Response of Copper and Magnesium Oxide Doped Lithium Potassium Borate Using a Monte Carlo N-Particle Code Simulation

The energy absorption coefficient of Cu-doped lithium potassium borate (LKB) dosimeter and TLD 100 was reported theoretically and checked by simulation of Monte Carlo n-particle code version 5 (MCNP5). The response of LKB:Cu for various photon energies (20 keV to 10 MeV) were determined by calculation, experiment and simulation. The obtained results were discussed and compared with TLD 100. For more precise results, the geometry specification, the source information, the material information and tallies were identified and fully described. The results obtained by simulation were determined based on the tally F6, which exhibited the response as energy-dependant on heating function instead of flux. The current results showed that the prepared dosimeter has a greater response than TLD 100 in the lower energy range and a flat response in the higher energy ranges (≥100 keV).

Thermoluminescence Dating of Colluvial Deposits and Its Application to Chronological Study of Paleoearthquakes

On the basis of studies of lithofacies features of colluvial deposits, applicability of thermoluminescence dating of the colluvial deposits at different lithofacies positions, and reliability of the dating result, the thermoluminescent ages of colluvial deposit from different types of faults were determined. From the above, the ages of paleoseismic events and their recurrence intervals on the related fault were deduced.

TECTONOTHERMAL EVOLUTION OF ORDOS BASIN BY THERMOLUMINESCENCE, NW CHINA

Ordos Basin is a remnant cratonic basin undergone multiple tectonothermal cyles, by the comprehensive study of thermoluminescence combined with vitrinite reflectance,magmatism, metamorphism and tectonosedimentation in the basin. Highly geothermal field,strong crustal movement existed in the basin during Archean to Paleoproterozoic. Since Mesoproterozoic, the tectonothermal nature has been relatively stable in Ordos Basin, associating with constant subsidence or uplift sometimes,while heat flow has still been high in the vicinityof the basin with strong activation of graben structural system because of the upwarding mantle creep flow. Two tectonothermal evolution stages and four developing periods can be recongnized in Ordos Basin,i. e. Pre-Mesoproterozoic stage consisting of Archean much higher geothermal geodome period and Paleoproterozoic higher-Reothermal geosyncline period,Mesoproterozolc to present stage including Mesoproterozoic to early Triassic low-geothermal geodepression period and late Triassic to present lowugeothermal uplift-subsidence period. The tectonothermal event at middle Triassic caused the uplift of the basin and the formation of the central paleodome,indicating that the basin entered its residual developing period of the platform. During the residual stable developing period of plat form,the creeping of the mantle increased and the heat flow changed to be high,accompanied by wide spreading eruption of basalt, such as that in Yimeng Uplift area,while the tectonic activity has been quite strong in the surrounding of the basin and the surrounding obviously overthrusted over the basin. Since Triassic, the basin has been gradually uplifted and its tectonism has migrated westward. The tectonothermal event may predicted the breakup of ordos Basin.

Developing Suitable Sensitive Compound Semiconductor Materials Doped by Transition Metals for Occupational Thermoluminescence Dosimetry

The essential objective of radiation dosimetry is to develop suitable sensitive materials for different measurements in radiation fields. Our exploration is to find potentially suitable high gamma radiation dosimeters in the range from 0.5E4 to 1.5E4 Gy. Gamma rays source (60Co, 136 Gy/min) has been used. Many compound semiconductor materials were prepared and investigated. Thermoluminescence (TL) glow curve was analyzed into its component by analytical segregation program using computerized glow curve deconvolution (CGCD). Three zero dose readings for non-irradiated powders of the materials have been taken as lower limit of detection. The results indicated that some of the tested materials have exhibited TL linearly with respect to dose. In addition, dose response of these materials was found to be useful for high radiation dosimetry. Glow curve structures exhibited several peaks corresponding to the various energies of the emptied traps. Variation in the standard deviation for reusability cycles has been ten readout. The fading at ambient temperature was studied up to 60 days which reached a relative stability (~1.5% for all), 10 days after irradiation. A typical glow curve of CoPa which irradiated with 1.5E4 Gy was analyzed. Characterizations of tested materials indicated that crystals of ZnLa:Li, ZnLa:Cd, and ZnLa:Cr have stable and increasing thermoluminescent responses with high gamma radiation dose range. Special glow peaks can be used as estimators for absorbed doses as well as re-estimation for time elapsed exposures.

Simultaneous Thermoluminescence and Thermally Stimulated Current in Polyamide

We have obtained simultaneous thermoluminescence (TL) and thermally Stimulated current (TSC) spectra in two types of polyamide film, such as nylons 6 and 11 under study of electron detrapping and recombination. There are three main relaxation peaks or regions, designated γ,β and α in order of increasing temperature in the TSC spectra, in contrast, a high temperature relaxation peak in TL spectra disappears. The centers or peaks of these relaxation regions are located at near 180, 230 and 310 K, respectively, deviating±10 K. However. we also observed two anomalous phenomena: first, a very large, short-circuited, thermally stimulated discharge current (TSDC) up to 10-8 A, but reversible in direction for non-polarized nylons 6 and 11, even after several times repeatedly; secondly, no TL signal except for non-polarized nylon 6 film.

Thermoluminescence characterization of natural and synthetic irradiated Ce-monazites

The thermoluminescence(TL)emission of synthetic and natural Ce-monazites was characterized here to determine the potential application in the identification of microscopic defects from a qualitative point of view trying to link each TL peak to a chemical-physical process.The kinetic parameters that lead the luminescence processes were calculated by means of variable heating rate and computing glow curve deconvolution methods and allow identifying three groups of components at~90,130 and 290℃(for the mineral sample)and~90,170,220,270 and 320℃(for the synthetic CePO_(4):Nd_(0.20),La_(0.25)).The main differences appreciated in these complex TL curves are mainly due to(i)the content of impurities(natural sample contains lanthanides as well as U 0.60%and Th 5.22%)and(ii)the degree of crystallinity of the samples which is directly related to the type of impurities(synthetic monazite relies only on Nd and La).The behavior of the dose response in the range of 1-8 Gy is similar for both samples;the TL intensity increases linearly as the dose increases without changes in the position of the maxima,denoting first-order kinetic luminescence mechanism.Each peak could be mostly associated with structural defects(i.e.,phase transitions),chemical reactions(i.e.,Ce3+?Ce4+redox reaction,dehydration or dehydroxylation processes)or intrinsic defects(i.e.,Frenkel defects,ODCs or NBOHCs).

Thermoluminescence dating of the ancient Chinese porcelain using a regression method of saturation exponential in pre-dose technique

This paper studies the thermoluminescence (TL) dating of the ancient por- celain using a regression method of saturation exponential in the pre-dose technique. The experimental results show that the measured errors are 15% (±1σ) for the paleodose and 17% (±1σ) for the annual dose respectively, and the TL age error is 23% (±1σ) in this method. The larger Chinese porcelains from the museum and the nation-wide collectors have been dated by this method. The results show that the certainty about the authenticity testing is larger than 95%, and the measurable porcelains make up about 95% of the por- celain dated. It is very successful in discrimination for the imitations of ancient Chinese porcelains. This paper describes the measured principle and method for the paleodose of porcelains. The TL ages are dated by this method for the 39 shards and porcelains from past dynasties of China and the detailed data in the measurement are reported.

Evaluation for the paleodose in thermoluminescence dating of porcelain

Sources, components and calibration of paleodose were studied for proper evalua- tion of the paleodose of porcelain in thermoluminescence (TL) dating. In the TL dating of porcelain using the pre-dose technique, the β dose from the internal natural radiation in the body of porcelain is the first, the environmental dose the second, and the α dose negligible. Sample thickness of 0.2―0.5 mm was used in the paleodose calibration. For a porcelain sample of such thickness, the distribu- tion of β dose inside the sample was nonlinear when the sample (aluminium re- places porcelain in this experiment) was irradiated by a laboratory 90Sr-90Y β source. Therefore, the β dose used was only an average value. A distribution curve of β dose and the calculation of average β dose in the sample were obtained, according to the build-up and attenuation effects of β dose in the sample. The results showed that a sample thickness of 200 μm resulted in an average dose increment of about 4% compared to the surface whereas for a sample with a thickness of 400 μm, the average dose reduced by the same percentage, and that for a sample of 300 μm in thickness the average dose is equal to surface dose approximately. The average β dose in samples with various thickness can be obtained by the provided equations.

Low temperature thermoluminescence behaviour of Y_2O_3 nanoparticles

Y_2O_3 nanoparticles were investigated using low temperature thermoluminescence (TL) experiments. TL glow curve recorded at constant heating rate of 0.4 K/s exhibits seven peaks around 19, 62, 91,115,162,196 and 215 K. Activation energies and characteristics of traps responsible for observed curves were revealed under the light of results of initial rise analyses and T_(max)-T_(stop) experimental methods. Analyses of TL curves obtained at different stopping temperatures resulted in presence of one quasi-continuously distributed trap with activation energies increasing from 18 to 24 meV and six single trapping centers at49, 117, 315, 409, 651 and 740 meV. Activation energies of all revealed centers were reported in the present paper. Structural characterization of Y_2O_3 nanoparticles was accomplished using X-ray diffraction and scanning electron microscopy measurements.

Investigation of thermoluminescence in Li_2B_4O_7 phosphors doped with Cu, Ag and Mg

Li2B4O7 （LBO）:Cu,Ag,Mg phosphors have been prepared by the sintering technique. The roles of the Ag and Mg dopants in the phosphors have been studied using the methods of thermoluminescence （TL） glow curves and TL 3D spectra. The results indicated that proper concentrations of Ag and Mg can enhance the TL of LBO:Cu. It was also indicated that the intensity of TL peak at 130℃ is reduced with the in- creasing Ag concentration, and enhanced with the increasing Mg concentration. From the TL 3D spectra, three emission bands （λ1 = 421 nm, λ2 = 380 nm, λ3 = 350 nm） were observed: the intensity of low energy emission band is reduced and that of the high energy is enhanced with the increasing dopant Ag; on the contrary, the intensity of low energy emission band is enhanced and that of the high energy one is reduced with the increasing dopant Mg.

Thermoluminescence characteristics of quartz implanted by nickel ion

The implantation of artificial quartz with nickel ion has succeeded in using a heavy ion accelerator. The quartz with nickel ion is called "nickel quartz". The sensitivity of their thermoluminescence (TL) response to the beta radiation was decreased with the increasing of irradiating and heating times. Two TL characteristics have appeared: the sensitivity of TL response at lower temperature (110℃) peaks of the nickel quartz to beta radiation is higher than that of the pure quartz, this results from the Ni +1 ion entering the quartz lattice; and a new peak appearing at 445℃ may be related with both Ni +1 and Ni +3.

Study and progress of the thermoluminescence dating of the ancient pottery and porcelain

Two standard methods,the "fine-grain technique" and the "quartz inclusion technique",and a new method,the pre-dose saturation exponential technique in thermoluminescence(TL)dating of ancient pottery and porcelain were reviewed,especially for the measurement of the paleodose and the annual dose.The two standard methods have been acknowledged in domain of TL dating and are used widely for age determination in archaeology and geology.As a dating tool the TL technique has been of great success in authentication of ancient ceramic art objects.However,a few complicated factors limit the precision and accuracy in age determination.These complicated factors are analyzed and discussed.Therefore,although ceramic TL dating can in general solve the problem of authentication of ancient ceramics,there are still complexities that require further research and study.

Thermoluminescence glow curve analysis and kinetic parameters of Dy-doped BaSi_(2)O_(5)phosphor

In this paper,Dy^(3+)incorporated BaSi_(2)O_(5)phosphors were synthesized by gel co mbustion method and characterized by X-ray diffraction(XRD).The effects of various heating rate s on thermoluminescence(TL)kinetics and glow peak temperatures of Dy^(3+)incorporated BaSi_(2)O_(5)phosphors exposed toβirradiation at room temperature were investigated.The glow curves of the phosphor exposed toβ-irradiation(0.1-100 Gy)consist of four main peaks located at 87,130,271,and 327℃and exhibit a good linearity between 0.1 and100 Gy.Three experimental techniques including variable heating rate(VHR),repeated initial rise(RIR),peak shape(PS)and computerized glow curve deconvolution(CGCD)were employed to determine TL kinetic parameters.Our findings indicate that the TL glow peaks of the phosphor obey first-order kinetics.Analysis of the main dosimetric peaks through the techniques mentio ned above indicates that activation energies(E)and pre-exponential factor(s)are in the range of 0.80-1.50 eV and 1.15×10^(8)-3.28×10^(13)s^(-1).Additionally,it is found that the temperature of the glow peaks shifts toward the higher temperatures and the TL intensity smoothly decreases as the heating rate increases.The effect on the TL intensities and glow peak temperatu res of the heating rate is discussed in terms of thermal quenching.

THERMOLUMINESCENCE(TL) DATING OF THE DEPOSITED CARBONATES FORMED IN LATE GEOLOGICAL HISTORY PERIOD

Deposited carbonates are formed by trickles of solution from limestone.It is usually seen as stalactite,

DETERMINATION OF SLIDING SPEED OF LAND SLIDE ACCORDING TO TEMPERATURE OF THERMOLUMINESCENCE

Determination of the sliding speed of ancient and old landslides is one of the most difficult problems in landslide research. Previously, the sliding speed was estimated according to the morphology of slided mass, sliding distance and other indicators. The obtained results depending upon experiences of investigators are usually of low reliability.

Spectral study on feldspar thermoluminescence process

Feldspar thermoluminescence fading phenomena were investigated here by using newly-constructed thermoluminescence spectrometer on the basis of charge-cou-pled detector,and thereafter the discussion and explanation on feldspar TL fading mechanism were presented. The experimental results show that the fading rate of feldspar TL depends on both wavelength and stimulated temperature,and normally the feldspar TL in every region of wavelength and temperature shows different traits,namely the low temperature TL (170℃-190℃) fading at the rate of logarith-mic function and furthermore the TL of different wavelengths fading at approxi-mately the same rate on the condition of 160℃ preheating. While the medium and high temperature TLs (290℃-400℃) do not show much thermal fading,their fading rate at room temperature invariably correlates well with their wavelength,namely the longer TL wavelength,the slower TL fading rate. The thermal instability of traps and the quantum-mechanical tunneling effects can explain the above fading phe-nomena respectively. It is recognized that feldspar TL fading depends on its wave-length,and furthermore new aspects of the solid thermoluminescence process can be displayed by the combination of three-dimensional TL spectral analysis and thermal fading or anomalous fading of TL for feldspar.

Iron-quartz system: A thermoluminescence dosimeter

MINERALS,rocks and fossils are the major objects in the dating laboratory with thermolumi-nescence(TL),optical luminescence(OL)or electron spin resonance(ESR)techniques.

High temperature thermoluminescence of BaFCl: Eu^(2+)

High temperature (from room temperature to 773 K) thermoluminescence of BaFCl: Eu2+ is reported. Three new glow peaks have been found to be caused respectively by F2-, F3 - and F4- centers which are the aggregates of F centers. Physical parameters characterizing those peaks are present. It is pointed out that the thermoluminescence process in BaFCl:Eu2+ is very complex. Accompanying this process, there occur electron transfers among different centers and dissociation of the aggregates.