便携式X射线荧光现场分析壁画颜料适用性研究——以西藏拉萨大昭寺壁画为例

The applicability analysis of PXRF in situ for the pigments on wall paintings at Jokhang Monastery, Lhasa,Tibet.

便携式X射线荧光光谱仪作为快捷的无损分析技术,广泛应用于壁画文物的现场分析中。本文利用便携式X射线荧光光谱仪分析了西藏拉萨大昭寺转经廊壁画,选取部分样品,利用实验室X射线荧光分析,发现所分析颜料的主要显色元素具有一致性,并利用拉曼光谱确定了壁画颜料的成分。通过比较研究,发现便携式X射线荧光光谱仪可确定大部分色彩较为纯正的颜料的成分,同时,由于西藏拉萨大昭寺壁画颜料的杂多性,对于含砷的橙色颜料、含砷或含铅与含铁的黄色颜料、含铜砷的绿色颜料、含钙硫的白色颜料、群青与孔雀石的混合颜料则需结合拉曼光谱确定之。本研究工作显示,利用便携式X射线荧光光谱仪开展现场检测,可极大地减少实验室分析样品的取样数量,有利于壁画颜料的无损分析与微损分析。

As a non-destructive and in situ testing technique, portable XRF （PXRF） has been widely applied on the elemental analysis of ancient artifacts. In this work, PXRF was applied on pigments in wall paintings at Jokhang Monastery, Lhasa, Tibet, China. Some pigments were sampled and examined by the XRF in laboratory （LXRF）, and then confirmed by Raman spectroscopy. It was found that most pure pigments successfully by PXRF by comparison with the data acquired via LXRF. However, some complex pigments such as As-based orange pigments, Fe, As and Pb-based yellow pigments, Cu-As-based green pigment, Ca-S-based white pigment and blue mixture pigment of Ultramarine blue and malachite, should be identified along with Raman spectroscopy. In conclusion, as a non-destructive and in situ testing technique, PXRF is very suitable for large-scale investigation of wall painting pigments in situ.