Accurate Luminescence Dating: Developing Combined Spectral- and Time-Resolved OSL

获取特定沉积物的沉积日期，或考古文物的制作年代，是了解景观发展、早期原始人的迁徙和史前人类活动的关键挑战之一。测定沉淀物和人工制品年代的最成功的方法之一是光激发发光(OSL)。在完全黑暗中采集的样本在暴露在光线下时会发出微小的辉光，这种发光的强度取决于样本的年龄。这项研究将建造一种仪器，不仅可以测量发光的强度，还可以测量其颜色(光谱分辨率)。商业约会工具只能测量强度。要做到这一点，我们将建造一种工作原理与商业系统不同的探测器，它将使用成像探测器技术中最先进的技术。一旦项目的这一部分成功，我们将以每秒1000次的速度打开和关闭刺激，并看看结果是如何打开和关闭OSL的。我们将观察到刺激脉冲和发出的光脉冲之间的轻微延迟(寿命)，以这种方式研究光被称为时间分辨率。持续时间从ns(即十亿分之一秒)到几秒不等。通过观察寿命，我们可以分离出矿物中不同结构(称为“中心”)产生的光。当两个中心恰好发出相同颜色的光时，对寿命的分析提供了一条将它们分开的途径。我们预计，通过只观察具有特定颜色和寿命的光的强度，即通过使用一种可以结合光谱和时间分辨率研究光的系统，我们将获得更好的年龄估计。我们将用新系统分析一组已经使用商业(RISO)系统研究过的样本，看看我们的仪器是否产生了显着的改进。这些样品包括两种最重要的矿物--石英和长石--并将对那些提供了准确年龄估计的矿物与那些测年不成功的矿物进行比较。通过这种方式，我们将确定结合光谱和时间分辨的OSL是否是传统OSL方法的重大进步。

Obtaining the dates at which particular sediments were laid down, or the ages when archaeological artefacts were made, is one of the key challenges to understanding landscape development, the migration of early hominids and the activity of Prehistoric man. One of the most successful means of dating sedimentation and human artefacts is Optically Stimulated Luminescence (OSL). Samples that are collected in total darkness emit a tiny glow when they are exposed to light, and the intensity of this glow is dependent on the age of the sample. The present study will build an instrument that measures not only the intensity of the glow, but also its colour ('spectral resolution'). Commercial dating instruments can only measure the intensity. To do this, we will build a detector that works on a different principle to the commercial systems, and which will use the most modern advances in imaging detector technology. Once this part of the project is successful, we will switch the stimulation on and off at e.g. one thousand times a second and see how the resultant OSL switches on and off. We will observe a slight delay (the 'lifetime') between the stimulation pulses and the pulses of light coming out, and studying the light in this way is called 'time-resolution'. The lifetime will vary from ns (i.e. billionths of a second) to a few seconds in duration. By looking at the lifetimes, we can separate out light generated by different structures (called 'centres') within the mineral. Where two centres happen to emit light of the same colour, analysis of the lifetimes provides a route to separate them. We anticipate that we will obtain better age estimates by only looking at the intensity of light emitted with particular colours and lifetimes, i.e. by using a system that can study the light with combined spectral and time-resolution. We will analyse a suite of samples with the new system that have been already been studied using a commercial (Riso) system to see whether our instrument produces significant improvements. The samples include the two most important minerals for dating - quartz and feldspar - and will compare and contrast minerals which have provided accurate age estimates with those for which dating has been unsuccessful. In this manner, we will determine whether combined spectral- and time-resolved OSL is a major advance on traditional OSL methods.