石英中Al和Ti-Li中心ESR信号的热稳定性

IF 1.6 3区物理与天体物理 Q2 NUCLEAR SCIENCE & TECHNOLOGY

Radiation Measurements Pub Date : 2025-02-01 DOI:10.1016/j.radmeas.2025.107380

Naoya Obata , Shin Toyoda

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引用次数: 0

摘要

利用两个具有独立年代估计的日本第四纪龙脑样品和一个现代沉积物样品，系统地研究了龙脑石英中Al和Ti-Li中心的热稳定性。两种样品的Ti-Li中心在加热后均呈两步下降，表明存在高温部分和低温部分。Al中心的热稳定性与Ti-Li中心的低温部分相似，在19℃时的特征衰减时间约为104年。Ti-Li中心显示等效剂量，在240-300°C预热，与独立年龄控制一致。而Ti-Li中心稳定部分的剂量响应曲线在2 kGy左右饱和，对应的年龄值为1 Ma。因此，麻黄的ESR定年可能仅限于小于1ma的样品。在低于1kgy的剂量范围内，加热约180°C时，Ti-Li中心被增强。这种增强对现有样品的测年结果影响不大。我们建议引入预热，以去除钛-锂中心的不稳定部分，并在检查剂量反应时适应这种增加。

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Thermal stability of the ESR signals of the Al and Ti-Li centers in quartz of tephra

The thermal stability of the Al and Ti-Li centers in quartz of tephra was systematically investigated in terms of their decay kinetics using two Quaternary tephra samples from Japan, which have independent age estimates, and one modern sediment sample. The Ti-Li center observed in both tephra samples showed a two-step decrease upon heating, indicating the presence of a high temperature part and a low temperature part. The thermal stability of the Al center was found to be similar to the low temperature part of the Ti-Li center, where the characteristic decay times at 19 °C were obtained to be in the order of 10⁴ years. The Ti-Li center showed equivalent doses, with preheating at 240–300 °C, consistent with independent age control. However, the dose response curve of the stable part of the Ti-Li center was saturated at about 2 kGy, which corresponds to an age value of 1 Ma. Therefore, the ESR dating of tephra is possibly limited to samples less than 1 Ma. It was also found that the Ti-Li center is enhanced by heating, around 180 °C in the dose range below 1 kGy. This enhancement has little influence on the dating results for the present samples. We recommend introducing preheating in order to remove the unstable part of the Ti-Li center and to accommodate this increase when examining the dose response.

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来源期刊

Radiation Measurements 工程技术-核科学技术

CiteScore

4.10

自引率

20.00%

发文量

116

审稿时长

48 days

期刊介绍： The journal seeks to publish papers that present advances in the following areas: spontaneous and stimulated luminescence (including scintillating materials, thermoluminescence, and optically stimulated luminescence); electron spin resonance of natural and synthetic materials; the physics, design and performance of radiation measurements (including computational modelling such as electronic transport simulations); the novel basic aspects of radiation measurement in medical physics. Studies of energy-transfer phenomena, track physics and microdosimetry are also of interest to the journal. Applications relevant to the journal, particularly where they present novel detection techniques, novel analytical approaches or novel materials, include: personal dosimetry (including dosimetric quantities, active/electronic and passive monitoring techniques for photon, neutron and charged-particle exposures); environmental dosimetry (including methodological advances and predictive models related to radon, but generally excluding local survey results of radon where the main aim is to establish the radiation risk to populations); cosmic and high-energy radiation measurements (including dosimetry, space radiation effects, and single event upsets); dosimetry-based archaeological and Quaternary dating; dosimetry-based approaches to thermochronometry; accident and retrospective dosimetry (including activation detectors), and dosimetry and measurements related to medical applications.