Li Yueer, Creange Sara, Zhou Zhou, Southworth William, Pappot Arie, van Eijck Lambert
Delft University of Technology, Faculty of Applied Sciences, Delft, 2629JB-15, The Netherlands.
Rijksmuseum, Amsterdam, 1071 XX, The Netherlands.
Sci Rep. 2024 Nov 22;14(1):28982. doi: 10.1038/s41598-024-80047-4.
Neutron tomography is gaining popularity particularly in cultural heritage research, for non-destructively analysing the inner structure of bulk metal artefacts, such as bronzes, but the induced temporary decay radiation is often considered as a drawback. However, this delayed gamma-emission can be put to good use: by performing gamma spectroscopy after neutron tomography, the interior elemental composition of artefacts can be obtained "for free". Inspired by this, we propose a ray-tracing approach to non-invasively quantify both interior geometry and elemental composition using only a single neutron tomography experiment. This strategy aligns well with both the aim for efficient use of neutron beam time and the expectation from curators and conservators for minimal neutron irradiation. Here, we outline the core principle of this method, demonstrate the extent of its quantification capability on bulk objects of known composition by fusing neutron tomography and delayed-gamma spectroscopy data sets. We also showcase its practical application on an ancient solid-cast Indonesian bronze statuette, by which we gain insights into how the pristine inner bronze segregated into a different composition than the surrounding shell. Similarly, the method allows us to quantify the composition of a hidden offering in the statuette that consecrates the bronze for worship purposes.
中子断层扫描在文化遗产研究中越来越受欢迎，特别是用于对大型金属文物（如青铜器）的内部结构进行无损分析，但诱导产生的临时衰变辐射通常被视为一个缺点。然而，这种延迟的伽马发射可以得到很好的利用：通过在中子断层扫描后进行伽马能谱分析，可以“免费”获得文物的内部元素组成。受此启发，我们提出了一种射线追踪方法，仅使用一次中子断层扫描实验就可以非侵入性地量化内部几何形状和元素组成。这种策略与有效利用中子束时间的目标以及馆长和文物保护者对最小化中子辐照的期望非常吻合。在这里，我们概述了该方法的核心原理，通过融合中子断层扫描和延迟伽马能谱数据集，展示了其对已知组成的大型物体的量化能力范围。我们还展示了其在一件古老的印度尼西亚实心铸造青铜小雕像上的实际应用，通过该应用我们深入了解了原始内部青铜如何与周围外壳分离成不同的组成。同样，该方法使我们能够量化小雕像中用于供奉青铜以供崇拜的隐藏祭品的组成。
