کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
8250951 | 1533429 | 2014 | 61 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Thermal quenching of far-red Fe3+ thermoluminescence of volcanic K-feldspars
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
فیزیک و نجوم
تشعشع
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Thermal quenching of far-red Fe3+ thermoluminescence of volcanic K-feldspars Thermal quenching of far-red Fe3+ thermoluminescence of volcanic K-feldspars](/preview/png/8250951.png)
چکیده انگلیسی
Strong thermal quenching is observed from 77 to 550Â K in the far-red luminescence of K-feldspars. This far-red emission, next to the emission in the UV-to-blue spectrum recorded for thermoluminescence (TL), is reported in most alkaline feldspars with a characteristic peak centered on 710Â nm with a width of 100Â nm. This emission was observed by cathodoluminescence (CL) at room temperature (RT) for more than 30Â K-feldspars, ranging from volcanic sanidines to granitic microclines and sediments and it is attributed to an Fe3+ impurity. Contrary to 'blue' emission in volcanic feldspars, the far-red emission displays very low anomalous fading (AF). This makes it attractive for dating purposes; however, it has weak natural TL intensity, even at saturation, which competes with the black-body emission of the heater plate. This is in contrast to an intense tunneling afterglow at liquid nitrogen temperature (LNT). Further observations show that the disadvantage of weak TL can be overcome. Photoluminescence (PL) under UV shows a very strong thermal quenching effect of the far-red emission from 77 to 550Â K, which accounts for the above contrast. Near the LNT, the far-red Fe3+ photoluminescence is at a maximum and is dominant over other emissions in the spectrum. However, as the temperature increases, the efficiency decreases, falling to well below one percent, whereas the 'blue' emissions remain stable. This thermal quenching effect in photoluminescence is paralleled in TL. After irradiation and during storage at RT, whereas the 'blue' emission in volcanic feldspars is affected by 'fast' anomalous fading, charge trapped at Fe3+ centers as latent far-red emission is almost stable. As the TL evolves and the extant 'blue' emission is emitted, more and more of the trapped charge associated with far-red emission recombines non-radiatively, resulting in an efficiency for emission in natural TL that is less than one percent. A modified band model, which calls for 'hopping' conductivity during the storage, accounts for the anomalous fading. Trap emptying at lower temperatures should lead to better use of the stable latent far-red stored charge for the dating of volcanic deposits.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Radiation Measurements - Volume 61, February 2014, Pages 52-73
Journal: Radiation Measurements - Volume 61, February 2014, Pages 52-73
نویسندگان
Raphaël Visocekas, Carlos Barthou, Philippe Blanc,