We measured the apatite etch rate νR in 5.5 M HNO3 at 21 °C as a function of orientation. Results for Durango apatite evidence that νR varies by a factor >5 with angle to the c-axis. Our measurements also provided track etch rates νT and surface etch rates νS. However, these cannot be combined for calculating track etching or counting efficiencies. By inserting the measured etch rates in a recent model, we calculate the geometries and dimensions of surface tracks in different apatite faces. The proposed model must be recalibrated for different etching protocols and adapted for other minerals. We submit that the new model justifies reviewing track counting efficiencies based on the existing (νB-νT) etch model. We anticipate that this will have an effect on practical aspects of fission track dating. Single-track step-etch data show that the confined track lengths increase with etch time at a decreasing average rate νL that differs from the track etch rate νT and the apatite etch rate νR. Both νT and νL exhibit large track-to-track differences that produce irreducible length variation related to the latent-track structure resulting from formation and annealing. Step etching and track width measurements are effective for reducing or eliminating procedure-related artifacts from track length data, and so for accessing more fundamental track properties.

中文翻译：

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磷灰石中裂变径迹蚀刻的定量描述

我们测量了21°C下5.5 M HNO3中磷灰石的腐蚀速率νR与取向的关系。杜兰戈磷灰石的结果表明νR与c轴的角度变化> 5倍。我们的测量还提供了轨道蚀刻速率νT和表面蚀刻速率νS。但是，不能将它们组合起来用于计算轨迹蚀刻或计数效率。通过在最近的模型中插入测得的蚀刻速率，我们可以计算出不同磷灰石表面中表面轨迹的几何形状和尺寸。建议的模型必须针对不同的蚀刻方案进行重新校准，并适用于其他矿物。我们认为，新模型证明了基于现有（vB-vT）蚀刻模型的复查轨迹计数效率是合理的。我们预计这将对裂变径迹测年的实际方面产生影响。单迹线步刻蚀数据表明，受限的迹线长度随刻蚀时间的增加而以平均速率νL减小，而平均速率νL与迹线刻蚀速率νT和磷灰石刻蚀速率νR不同。νT和νL都显示出较大的磁道间差异，这会产生与形成和退火导致的潜在磁道结构有关的不可减少的长度变化。阶梯蚀刻和磁道宽度测量可有效减少或消除磁道长度数据中与过程相关的伪影，从而获得更基本的磁道特性。νT和νL都显示出较大的磁道间差异，这会产生与形成和退火导致的潜在磁道结构有关的不可减少的长度变化。阶梯蚀刻和磁道宽度测量可有效减少或消除磁道长度数据中与过程相关的伪影，从而获得更基本的磁道特性。νT和νL都显示出较大的磁道间差异，这会产生与形成和退火导致的潜在磁道结构有关的不可减少的长度变化。阶梯蚀刻和磁道宽度测量可有效减少或消除磁道长度数据中与过程相关的伪影，从而获得更基本的磁道特性。