کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1686702 | 1010614 | 2007 | 8 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Measurements of fossil confined fission tracks in ion-irradiated apatite samples with low track densities
دانلود مقاله + سفارش ترجمه
دانلود مقاله ISI انگلیسی
رایگان برای ایرانیان
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی مواد
سطوح، پوششها و فیلمها
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
This investigation looks into the potential and consequences of combined ion-irradiation and sequential etching as means for increasing the number of measurable horizontal confined tracks in geological apatite samples with low fission-track densities. The gain is substantial but varies between samples depending on the size and aspect of the grains and the fraction of prismatic sections. The average maximum gain (Ïion â 2 Ã 06 cmâ2; lion â 30 μm; θion = 15°; 35 s etching in 4 M HNO3 at 25 °C) is â¼200 times. Greater gains are achieved in some cases but there are indications of saturation. For maximum effect, the beam parameters should be tailored to the properties of the sample. The effectiveness of sequential etching is much greater than expected from the ratio of the etching times or of the track cross-sections at successive etching times. The number of confined tracks increases â¼3.5 times between te = 15 s and 25 s and a further â¼2 times between te = 25 s and 35 s. The total increase due to etching (â¼7 times) is still much lower than that from ion-irradiation alone, estimated at â¼30 times. Ion-irradiation has no significant effect on the etchable lengths of individual confined tracks and no pronounced effect on their angular distribution. Sequential etching has no apparent effect on their angular distribution; its effects on the lengths of individual tracks, mean confined-track length, length distribution and anisotropy are less clear. Overall, our results document a quasi-isotropic increase of the mean confined-track length between te = 15 s and 25 s and an according quasi-uniform shift of the track-length distribution towards longer lengths but no significant further increase nor shift between te = 25 s and 35 s. This trend varies between samples because the relationship between the mean track length and that of individual confined tracks is affected by complex sampling issues that require detailed investigation.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms - Volume 259, Issue 2, June 2007, Pages 943-950
Journal: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms - Volume 259, Issue 2, June 2007, Pages 943-950
نویسندگان
Myo Min, Eva Enkelmann, Raymond Jonckheere, Christina Trautmann, Lothar Ratschbacher,