Thermo- and cathodoluminescence properties of lepidolite

Abstract

Lepidolite, K(Li,Al) 3 (Si,Al) 4 O 10 (F,OH) 2 , and many of the related phyllosilicate mineral of the mica group have been well studied from the chemical and structural point of view; however, to the best of our knowledge, studies on their luminescence properties have been scarcely reported. This work focuses on the thermoluminescence (TL) and cathodoluminescence (CL) response of a natural lepidolite from Portugal previously characterized by means of environmental scanning electron microscope (ESEM) and Xray fluorescence (XRF) and atomic absorption spectroscopy (AAS) techniques. The complexity of the thermoluminescence glow curves of non-irradiated and 1Gy irradiated samples suggests a structure of a continuous trap distribution involving multiorder kinetics. UV-IR CL spectral emission shows seven peaks centered at 330, 397, 441, 489, 563, 700 and 769 nm. Such emission bands could be due to (i) structural defects, i. e.[AlO 4 ] or non-bridging oxygen hole centers, and (ii) the presence of point defects associated with Mn 2+ and Fe 3+ .

Effect of the irradiation dose on the luminescence emission of a Mg-rich phyllosilicate

“…As is appreciated, the mathematical fitting indicates a lineal evolution that is linked to a group of components, where the fitting regression coefficient (r) is 0.997. This behaviour should correspond to a continuous trap distribution also observed in other different natural materials previously studied in our laboratory (phyllosilicates -lepidolite- [4], K-rich aluminosilicate, leucite [31,32] ) and polymineral materials (meteorites [39] ).…”

“…Many Si-O bonds undergo an additional stress due to different processes, namely dehydration or dehydroxylation or both processes, involving losses of H 2 O, with hydrogen atoms bonded to the lattice, or breaking of hydroxyl groups, also bonded to the silicate framework. The emission at 400 nm, as suggested by Itoh and coworkers [27], can be attributed to 4 ]°are formed during self-diffusion processes through the bulk and interfaces due to changes in the temperature of the lattice [28]. XRF analysis shows the presence of a content of 0.65 % of Al in the studied sample that seems to be enough to produce such UV-blue emission.…”

“…5). Irradiated sepiolite aliquots exhibits a TL sensitivity similar to other phyllosilicates studied in our lab under the same conditions (kaolinite [6] or lepidolite [4], although quite less intensity luminescence signal respect to other silicates (microcline [43] or albite [44]). Induced TL glow curve displays (i) a higher temperature broad maximum peaked at 320°C that is hardly affected by the irradiation and (ii) a lower temperature group of components in the range of 50-170°C, with a very complex structure, that is directly related to the radiation effect.…”

“…It is precisely for this last application, which makes this ubiquitous material of interest for dosimetric purposes in case of radiation accident or radiological terrorism where conventional monitoring has not been established. Similar to other phyllosilicates (lepidolite [4] or kaolinite [5,6]), sepiolite could exhibit useful luminescence-dosimetric properties, although this property has been scarcely studied. Only Bulur [7] performed a preliminary study considering the optically stimulated luminescence emission of a Turkish sepiolite.…”

SESIUM KLORIDA (CsCl) : TRANSPORT ION DALAM LARUTAN

“…Sehingga susunan kristal ini membentuk kisi kristal sederhana.Atom penyusun sesium klorida  (28.44 °C, 83.19 °F) (https://id.wikipedia.org/wiki/Sesium) Sesium (91-94) merupakan logam alkali (47; 95) yang memiliki no atom 55 dan berbentuk cair dalam suhu kamar berwarna putih keemasan. Sesium adalah logam alkali yang terdapat di lepidolite(96), pollucte (silikat aluminum dan Sesium basah) dan di sumber-sumber lainnya. Salah satu tempat yang menjadi sumber terkaya yang mengandung Sesium terdapat di danau Bernic di Manitoba, Kanada.…”