This paper studies the thermoluminescence (TL) dating of the ancient porcelain 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 porcelain 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.

Sources, components and calibration of paleodose were studied for proper evaluation 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 distribution of β dose inside the sample was nonlinear when the sample (aluminium replaces porcelain in this experiment) was irradiated by a laboratory 90 Sr-90 Y 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. thermoluminescence dating, porcelain, paleodose, build-up, attenuation, average beta dose The sources and components of paleodose in porcelainThe thermoluminescence dating of ancient porcelain using the regression method of saturation exponential in the pre-dose technique has been reported [1] . The key to successful application of TL dating is to determine the paleodose of the ceramic as accurately as possible. Sources, components, and calibration of paleodose in the ceramic are important in this case. The sources and components of paleodose are very different, which depend on the method, sample and grain size or thickness of the sample. These issues must be thrashed out; or the TL age obtained will be wrong or confounded.

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 dating, pottery, porcelain It has been nearly 50 years since thermoluminescence (TL) was first detected in ancient pottery powder by Grögler et al. [1] and Kennedy and Knopff [2] . Thermoluminescence dating has made considerable progress and played a major role in archaeology and geology for the past 50 years. As a dating tool, the thermoluminescence technique has achieved a great success in the authentication of ancient ceramics, and no other scientific detection method can compare with it.Thermoluminescence is a physical phenomenon. The principle is that when solid is excited by ionization radiation, the accumulated radiation energy is stored in the crystal lattice; once the crystal is heated, the stored radiation energy is transferred immediately into photoenergy and is emitted as a kind of phosphorescence, which is thermoluminescence. Using this phenomoenon, we can determine the production date of ceramics and tiles and can also determine when the geology materials under consideration were heated for the last time. This new technique, developed since the 1960's, has been applied in archaeology and geology dating area. This technique has had a strong impact on museum collections stored in western countries. Some imitations of ancient pottery that had been exhibited in well-known international museums have been discovered [3][4][5] . The resulting 'Thermoluminescence Revolution' has solved puzzles about the authenticity of ancient pottery collections and caused a huge stir among antique collectors.TL is a function of the absorbed radiation dose. Hence, TL dating is mainly to measure two parameters: the paleodose (P) and the annual dose (D). P is the accumulated natural irradiation absorbed dose of the ceramic from manufacturing time to present day. D is the irradiation absorbed dose by a ceramic in one year. The TL age is equal to the "paleodose" divided by the "annual dose". In this way, we can obtain the manufacture date or the age of the ceramic by Paleodose( ) Age( ) . Annual dose( )Although the principle of TL dating is quite simple, it is still hard to obtain accurate values for the paleodose

The pre-dose technique is important for thermoluminescence (TL) dating of porcelain. The principle of pre-dose dating is based on two characteristics: thermal activation and radiation quenching of the porcelain. Based on these principles, two measurement methods, "the activation method" and "the quenching method", respectively, have been developed for evaluation of the porcelain paleodose. The paleodose values obtained are the same for the ages in the range of 100-1000 a BP for porcelains measured by these two methods. But for dating at lower age limits (less than 100 a BP), the activation method is more accurate; conversely, at higher age limits (greater than 1000 a BP) the quenching method is more accurate. In addition, two specific calculating methods are described for a few porcelains having anomalous activation and quenching characteristics that make these two methods invalid.porcelain, thermoluminescence dating, pre-dose technique, thermal activation, radiation quenchingThe pre-dose technique is very useful for thermoluminescence (TL) dating of porcelain. If a porcelain sample is rapidly heated to a high temperature, the 110℃ TL sensitivity of the previously absorbed dose (i.e. the cumulative dose resulting from natural radiation throughout the history of the specimen and that from the laboratory calibrating dose) will rise rapidly up to a maximum (saturation) value; this phenomenon is called "the thermal activation characteristic". In addition, after a sample receives an irradiating dose, the 110℃ TL sensitivity not only does not rise, but, on the contrary, falls to a level lower than before irradiation. This is called "the radiation quenching characteristic". Pre-dose dating is based simply on the thermal activation and the radiation quenching.The pre-dose effect is present mainly at 110℃ TL peak in quartz. Its "memory effect" can be used for evaluation of paleodose, as was realized by Fleming in 1969 [1] . Its use as a new dating method was suggested by Fleming in 1973 [2] . The pre-dose technique is used mainly for dating of young samples and for accidental dosimetry. Its range of application is not wide because of the characteristics of the pre-dose. The activation methodThe mechanism of thermal activation for the 110ºC TL peak in quartz can be explained as the TL sensitivity change is from the probability increment of the holes recombined by the electrons in the activated luminescence centre L. For details, see the energy-level model for the pre-dose effect of the 110℃ TL peak in quartz suggested by Zimmerman [3] , Chen [4] and Aitken [5] .