THERMOLUMINESCENT DATING: REFINEMENT OF THE QUARTZ INCLUSION METHOD
THERMOLUMINESCENT DATING: REFINEMENT OF THE QUARTZ INCLUSION METHOD
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热释光测年：石英内含物方法的改进
DOI：
10.1111/j.1475-4754.1970.tb00016.x
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发表时间：
1970
期刊：
影响因子：
1.6
通讯作者：
S. Fleming
中科院分区：
文献类型：
--
作者：
S. Fleming
在热释光测年的早期发展中，这种方法被认为是一种相对的方法，需要用已知年龄的样品进行校准。独立于其他年代学的绝对年龄首次使用包含技术获得（Fleming 1966）；本文描述了对该技术的后续修改以及综合测试程序的结果。由于对存在于陶器结构中的辐射剂量测定条件的进一步了解，在绝对基础上确定年代成为可能。加热粘土基质内结晶所积累的热释光是由天然同位素铀、钍和放射性成因钾的放射性衰变所产生的α、β和γ辐射混合辐射场的电离效应引起的。不同形式的辐射具有不同的穿透力，这是陶器剂量测定法在“石英包裹体”测年法中的优势。镶嵌在加热粘土基质中的石英颗粒（图1）经历来自该基质的α、β和γ辐射，但几乎完全没有内部自放射性（Fleming 1966，和附录A）。在包裹体/基体界面处发生的崩解产生的α粒子平均只能穿透约23pm，而在基体中更远的地方产生的粒子的穿透性则相对较小。对于直径为100 μ m / m的颗粒，这种几何形状导致α辐射剂量稀释到21 μ m / m的水平，对于铀系列，和25%的钍系列（Fleming 1969）。齐默尔曼（1967）也表明，在产生热释光时，α粒子的效率通常只有β或γ辐射的15%。结合这两个因素，可以预测这种石英包裹体基本上只经历β和γ辐射剂量。在1966年对一组从9块陶器碎片中分离出来的水晶碎片使用这一原理，在绝对的基础上，与它们的考古年龄一致，在30英寸/小时内。本文描述了如何提高精度，随后实现。仪器和测量程序的详细资料载于附录C。
In the early development of thermoluminescent dating the method was considered as a relative one that required calibration with known-age samples. Absolute ages independent of other chronology were first obtained using the inclusion technique (Fleming 1966); this paper describes subsequent modifications to this technique together with the results of a comprehensive test programme. Dating on an absolute basis became possible because of an improved understanding of the conditions of radiation dosimetry that exists in the structure of pottery. The thermoluminescence accumulated by crystals within the matrix of heated clay arises from the ionizing effects of a mixed radiation field of alpha, beta and gamma radiation originating from the radioactive decay of the natural isotopes, uranium, thorium and radiogenic potassium. The different forms of radiation have quite different penetrating power, which is the feature of pottery dosimetry that is used to advantage in the ‘quartz inclusion’dating method.A quartz grain embedded in a heated clay matrix (figure I) experiences alpha, beta and gamma radiation from that matrix, but is almost entirely free of internal self-radioactivity (Fleming 1966, and appendix A). Alpha particles arising from disintegrations occurring at the inclusion/matrix interface will only penetrate approximately 23 pm on average, while particles arising from further away in the matrix will be appropriately less penetrating. For grains of IOO pm diameter this geometry results in dilution of the alpha radiation dosage to a level of 21”/, for the uranium series, and 25% for the thorium series (Fleming 1969). Also Zimmerman (1967) has shown that alpha particles are typically only 15% as efficient as beta or gamma radiation in the creation of thermoluminescence. Combination of these two factors predicts that such a quartz inclusion experiences essentially only a beta and gamma radiation dosage. Use of this principle on a group of crystalline separates from 9 pottery sherds in 1966 yielded an agreement with their archaeological age to within 30”/, on an absolute basis. This paper describes how improved accuracy has subsequently been achieved. Details of the apparatus and measurement procedure are given in Appendix C.