Latent track formation in CR-39 and the role of dissolved oxygen

本文对CR-39核径迹探测器的潜迹进行了研究，得到了以下结果。通过结合径迹重叠模型的紫外光谱测量和微蚀刻探测器的原子力显微镜观测，确定了径向尺寸。发现轨道核心半径约为几纳米，几乎与阻止功率的三次根成正比。作为对照研究，考察了CR-39在低LET辐照下的刻蚀性能。对辐照后CR-39的体蚀刻速率随深度和剂量率的变化规律进行了解释，认为损伤形成过程是由辐射诱导的自由基与空气中的氧气反应决定的。这表明CR-39中的潜在径迹是通过沿离子路径的局部辐射诱导氧化过程而产生的。对CR-39的振动光谱、近红外光谱、傅里叶变换红外光谱和拉曼光谱进行了研究，以估算潜在径迹的化学结构。证实了辐照后的CR-39中产生了羟基。

The following results have been obtained for the present studies on the latent tracks in CR-39 nuclear track detector. The radial size of track core has been determined through UV spectral measurements combined to the model of track overlapping and by AFM observations of slightly etched detectors. The track core radius was found to be about a few nano-meters and almost proportional to the cubic root of stopping power. As a control study, the etching properties of CR-39, irradiated by low-LET radiation, has been examined. The observed depth-dependence and dose-rate dependence of the bulk etch rate of the irradiated CR-39 were explained that the damage formation process was governed by the reaction between the radiation induced radicals and the oxygen supplied from the air. This indicated that latent tracks in CR-39 are produced through local radiation induced oxidation process along the ion paths. Studies on vibration spectra, Near-IR, FT-IR and Raman spectra, of CR-39 have been also carried out to estimate the chemical structure of the latent tracks. The creation of OH group in irradiated CR-39 has been confirmed.