Electron-beam-induced annealing of natural zircon: a Raman spectroscopic study
Electron-beam-induced annealing of natural zircon: a Raman spectroscopic study
复制标题
天然锆石的电子束诱导退火：拉曼光谱研究
DOI：
--
复制
发表时间：
2017
影响因子：
1.4
通讯作者：
L. Nasdala
中科院分区：
文献类型：
--
作者：
T. Váczi;L. Nasdala
系统地研究了低能电子辐照对锆英石辐照损伤的退火效应。用电子探针聚焦电子束对天然锆石样品进行了辐照。系统地测试了束流和辐照时间的影响，并利用拉曼光谱测量了锆石的变化。我们的研究结果证实了加速电子束的损伤退火效应。我们表明，非热退火发生通过电子增强的缺陷反应和退火的程度是照射时间和束电流的函数。在我们的实验条件下，用加速电子束对锆石的辐射损伤进行完全退火是不可能的。我们的研究结果表明，离子辐照锆石的拉曼谱带展宽可能是通过声子约束来解释的，因为反冲团簇中晶体体积的估计畴尺寸随着α剂量的增加而减小。这一结果说明了在电子束和离子束分析之前进行拉曼光谱分析的重要性。为了避免在EPMA分析期间锆石中的损伤的不希望的束诱导退火，应当例如通过保持低的积分电荷和/或通过使电子束散焦来使每体积单位样品传递的电子能量最小化。
The annealing of radiation damage in zircon by low-energy electron irradiation was explored systematically. Natural zircon samples spanning a wide range of self-irradiation damage were irradiated with the focused electron beam of an electron probe microanalyser. The effects of beam current and irradiation time were tested systematically, and the changes in zircon were measured using Raman spectroscopy. Our results confirm the damage-annealing effect of an accelerated electron beam. We demonstrate that non-thermal annealing occurs through electron-enhanced defect reactions and that the extent of the annealing is a function of both the irradiation time and the beam current. The complete annealing of radiation damage in zircon by an accelerated electron beam was not possible under the conditions of our experiments. Our results indicate that Raman band broadening in ion-irradiated zircon can possibly be explained through phonon confinement, as the estimated domain sizes of the crystalline volume amid recoil clusters decrease with increasing α dose. The results underlay the importance of doing Raman spectroscopy before electron-beam and ion-beam analysis. To avoid unwanted beam-induced annealing of damage in zircon during EPMA analysis, the electron energy transferred per volume unit of sample should be minimised, for instance by keeping the integrated charge low and/or by defocusing the electron beam.