金云母中Alpha反冲径迹的蚀刻和退火行为

Etching and Annealing Behaviors of Alpha Recoil Tracks in Phlogopite

矿物中U、Th及其子核进行α衰变释放出α粒子时，剩余重核受到反冲而产生辐射损伤。在适当的条件下经化学蚀刻，这些辐射损伤成为在相干涉反差显微镜下可观测的核径迹。实验证明，蚀刻过程中，Alpha反冲径迹（ARTs）增长数和蚀刻时间成线性关系，随蚀刻时间增加，线性被破坏，最终达到一个“坪”。退火过程表明，Alpha反冲径迹的退火要比裂变径迹的退火容易，其退火率随退火时间的增长和温度的升高而增加，且温度对其影响显著，在350℃下加热样品20h，退火率达到90％左右，在400℃下加热4h，完成全退火。

When U and Th as well as their daughter nuclei emit aparticles afteradecays, the heavy residual nuclei are recoiled, leaving behind a trail of radiation damage in the mineral. The trail of radiation damage becomes a nuclear track when it is etched by chemical reagent under proper etching conditions. Then it can be observed under the phase-contrast interference microscope. It is proved that the number of ARTs increases linearly with the etching time during the initial etching process. With the increase of the etching time, the linearity is destroyed, and finally reaches a “plateau”. ARTs are annealed much more easily than fission tracks, as can be observed from the annealing process of ARTs. The annealing ratio increases with both annealing time and temperature, with the temperature exerting an obvious effect on it. It reaches 90% when the sample is heated for 20 hours under 350℃, and 100% when the sample is heated for 4 hours at 400℃.