热处理对古代瓷器热释光前剂量法测年的影响研究

Impact of Thermal Treatment on Thermoluminescence Pre-dose Dating of Ancient Porcelains

热释光测年技术是鉴定古陶瓷真伪和断代的重要手段,通过测量瓷器所释放的光子能量判断出瓷器从高温烧制后所接受的环境背景辐射能量总和,从而估算自高温烧制时间点至今所经过的时间。然而,若瓷器在保存过程中遭遇高温事件,其内部晶体累积的热释光能量将被全部或部分释放,导致测得的年龄可能并非瓷器烧制的真实年代。本研究通过实验,对古瓷器样品在不同温度下进行热处理,并利用热释光前剂量技术测量累计辐射剂量,以探讨热处理温度对热释光测年结果的影响。结果显示,300℃以下的热处理对测年结果无显著影响;当温度超过400℃时,测年结果随温度升高而减小;当温度达到600℃以上时,热释光信号完全消失。因此,为确保热释光测年的准确性,需要详细了解古瓷器的受热历史,当样品本底异常高的时候,应该考虑该样品是否经历过高温热事件。如果在古瓷器保存和修复过程中需要进行热处理,温度应严格控制在300℃以下,以避免对热释光信号造成干扰。这一发现对古陶瓷鉴定和保护工作具有重要的实践指导意义。

Thermoluminescence dating is an important means to identify the authenticity and dating of ancient ceramics,while the sum of the environmental background radiation energy received by the porcelain after high-temperature firing can be judged by measuring the photon energy released by porcelain,so as to estimate the time elapsed from high-temperature firing to the present.However,if the porcelain is subjected to a high temperature event during preservation,the thermoluminescence energy accumulated by the crystals inside the porcelain will be released in whole or in part,resulting in an age that may not be the actual one of the porcelain.In this study,ancient porcelain samples were subjected to heat treatment at different temperatures,while the cumulative radiation dose was measured by using thermoluminescence pre-dose technology to explore the effect of heating temperature on the results of thermoluminescence dating.It is showed that heating temperature below 300℃had no significant effect on the dating results.When the temperature exceeded 400℃,the dating results decreased with increasing temperature.When the temperature was higher than 600℃,the thermoluminescence signal disappears completely.Therefore,in order to ensure the accuracy of thermoluminescence dating,it is necessary to understand the heating history of ancient porcelain in detail.When the background level(S0)of the sample is abnormally high,it should be considered whether the sample has experienced an excessively high temperature event.If heat treatment is required during the preservation and restoration of ancient porcelain,the temperature should be strictly controlled below 300℃to avoid interference with the thermoluminescence signal.This discovery has important practical guiding significance for the identification and protection of ancient porcelain.