{"title":"裂变径迹定年中外探测器的几何因子","authors":"A.J.W. Gleadow, J.F. Lovering","doi":"10.1016/0145-224X(77)90003-5","DOIUrl":null,"url":null,"abstract":"<div><p>Induced-fission track densities have been compared on mica external track detectors (2π geometry) and internal mineral surfaces (4π geometry) for the minerals apatite, zircon and sphene. The track-density ratios indicate that the geometry factor relating these two track-registration geometries is indistinguishable from the ideal value of 0·5 (i.e. 2π/4π) for these minerals. External track detectors are not geometrically equivalent to external etching surfaces of a uranium-bearing material. Values significantly higher than 0·5 are caused by a low etching efficiency on the internal mineral surface. The etching efficiency varies with crystallographic orientation in zircon, and may be lowered after thermal annealing in sphene. Etching a mineral surface for spontaneous tracks has no observable effect on the uranium concentration of that surface. These observations have important implications for the use of the external-detector method in fission-track dating.</p></div>","PeriodicalId":100974,"journal":{"name":"Nuclear Track Detection","volume":"1 2","pages":"Pages 99-106"},"PeriodicalIF":0.0000,"publicationDate":"1977-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0145-224X(77)90003-5","citationCount":"104","resultStr":"{\"title\":\"Geometry factor for external detectors in fission track dating\",\"authors\":\"A.J.W. Gleadow, J.F. Lovering\",\"doi\":\"10.1016/0145-224X(77)90003-5\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>Induced-fission track densities have been compared on mica external track detectors (2π geometry) and internal mineral surfaces (4π geometry) for the minerals apatite, zircon and sphene. The track-density ratios indicate that the geometry factor relating these two track-registration geometries is indistinguishable from the ideal value of 0·5 (i.e. 2π/4π) for these minerals. External track detectors are not geometrically equivalent to external etching surfaces of a uranium-bearing material. Values significantly higher than 0·5 are caused by a low etching efficiency on the internal mineral surface. The etching efficiency varies with crystallographic orientation in zircon, and may be lowered after thermal annealing in sphene. Etching a mineral surface for spontaneous tracks has no observable effect on the uranium concentration of that surface. These observations have important implications for the use of the external-detector method in fission-track dating.</p></div>\",\"PeriodicalId\":100974,\"journal\":{\"name\":\"Nuclear Track Detection\",\"volume\":\"1 2\",\"pages\":\"Pages 99-106\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"1977-06-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://sci-hub-pdf.com/10.1016/0145-224X(77)90003-5\",\"citationCount\":\"104\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Nuclear Track Detection\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/0145224X77900035\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Nuclear Track Detection","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/0145224X77900035","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
Geometry factor for external detectors in fission track dating
Induced-fission track densities have been compared on mica external track detectors (2π geometry) and internal mineral surfaces (4π geometry) for the minerals apatite, zircon and sphene. The track-density ratios indicate that the geometry factor relating these two track-registration geometries is indistinguishable from the ideal value of 0·5 (i.e. 2π/4π) for these minerals. External track detectors are not geometrically equivalent to external etching surfaces of a uranium-bearing material. Values significantly higher than 0·5 are caused by a low etching efficiency on the internal mineral surface. The etching efficiency varies with crystallographic orientation in zircon, and may be lowered after thermal annealing in sphene. Etching a mineral surface for spontaneous tracks has no observable effect on the uranium concentration of that surface. These observations have important implications for the use of the external-detector method in fission-track dating.