scholarly journals PRODUÇÃO DE DOSÍMETROS TERMOLUMINESCENTES À BASE DE MgB4O7: Dy e MgB4O7:Tm

2017 ◽  
Vol 38 (1) ◽  
pp. 101
Author(s):  
Luiza Freire de Souza ◽  
Divanízia N. Souza
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
X Rays ◽  
Thermoluminescent Dosimetry ◽  
Undoped Material ◽  
Radiation Sources ◽  
Different Types ◽  
Acidic Conditions ◽  
Established Technique

The thermoluminescent dosimetry (TL) is a well-established technique for the detection of ionizing radiation in hospitals, clinics, and industrial establishments where there is the need to quantify the radiation. For this practice is require the use phosphors which are sensitive to radiation. Some phosphors are already commonly used in this practice, for example, TLD-100 (LiF: Mg, Ti), CaSO4:Tm and CaSO4:Dy. A compound that was most recently introduced in dosimetry and has many advantageous features to detect neutrons, electrons and gamma is the magnesium tetraborate (MgB4O7), but the undoped material is not good for dosimetry, since signal does not show satisfactory thermoluminescence. The present work presents the analysis of the compound MgB4O7 when doped with rare earth elements, thulium (Tm) and dysprosium (Dy). The production of MgB4O7: Dy and MgB4O7: Tm occurred under acidic conditions. Following the process of crystal growth, several tests were made on phosphors produced to verify the quality of materials as TL dosimeter. Initially, was made the identification of the crystalline phases found in the material, using the technique of X-ray diffractometry, and then were evaluated and compared the TL emission curves of the crystals with two different types of dopants, to this, the samples were irradiated with different radiation sources: 137Cs (0,66 MeV), 60Co (1.25 MeV) and X-rays (0.41 MeV) and based on the results was evaluated the energy dependence of phosphors. Another characteristic analyzed, was the decay of TL signal for the material (fading). The results show that the material can be an excellent TL dosimeter when doped with rare earth elements Dy and Tm.

A Rapid and Accurate X-Ray Determination of the Rare Earths Elements in Solid or Liquid Materials using the Double Dilution Method

1968 ◽  
Vol 12 ◽  
pp. 546-562
Author(s):  
R. Tertian
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Accurate Determination ◽  
Fluorescence Analysis ◽  
Dilution Method ◽  
Practical Advantage ◽  
X Ray ◽  
The Matrix

AbstractThe double dilution method has many important advantages. For any element to be determined, let us say A, It enables us to control or calculate the matrix factor (sum of the absorption end enhancement effects) for the sample being Investigated towards A radiation, and it furnishes corrected Intensities which are strictly proportional to A concentration. Thus the results are exact, whatever the general composition of the sample, their accuracy depending only on the quality of measurement and preparation. Another major practical advantage is that the method does not require systematic calibration but only a few permanent standards consisting of a pure compound or of an accurately known sample.The procedure has been tested successfully for accurate determination of rare earth elements using, for solid materials such as ores and oxide mixtures, the borax fusion technique. It also can be readily applied to liquids. All the rare earth elements can be titrated by that method, as well as yttrium, thorium and, if necessary, all the elements relevant to X-ray fluorescence analysis. The concentration range considered for solids is of one comprised between 0.5 and 100 % and, with a lesser accuracy, between 0.1 and 0-5 % Examples are given relative to the analysis of various ores. Finally it rcust be pointed out that the method is universal and applies to the analysis of every solid, especially ores, provided that they can be converted to solid or liquid solutions. It appears that most industrial analyses can be worked on In this way.

scholarly journals Geochemical Behaviour of Rare Earth Elements in Mining Environments under Non-Acidic Conditions

2013 ◽  
Vol 7 ◽  
pp. 578-581 ◽  
Author(s):  
Daniela Medas ◽  
Rosa Cidu ◽  
Giovanni De Giudici ◽  
Francesca Podda
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Geochemical Behaviour ◽  
Acidic Conditions

Variables in the radiation-attenuation of helminth larvae: the effect of differences in quality of radiation

Parasitology ◽  
1966 ◽  
Vol 56 (4) ◽  
pp. 651-656 ◽  
Author(s):  
T. Kassai ◽  
B. Fitzpatrick ◽  
W. Mulligan
Keyword(s):  
Agricultural Research ◽  
Dose Range ◽  
X Rays ◽  
British Council ◽  
Agricultural Research Council ◽  
Radiation Sources ◽  
Γ Rays ◽  
Low Radiation Doses ◽  
Total Worm Burden

A comparison has been made of the attenuating effect on N. brasiliensis larvae of X-rays (HVL, 8 mm Al) and γ-rays from 60Co over the range 10–80 kr. In the dose range where attenuation was manifested as a decrease in total worm burden the γ-rays had an RBE (relative biological effect) of 0-7 relative to the X-rays as unity.Because of the enhancement of infectivity occurring at low radiation doses, attenuation in this region is better assessed in terms of alteration to the sex-ratio of the parasite rather than effect on total population.This work was supported by grants from the Agricultural Research Council and the Horse Race Betting Levy Board, and was carried out during the tenure by one of the authors (T. Kassai) of a British Council exchange scholarship.Thanks are due to Dr T. Martin Young and Mr J. S. Orr of the Radiotherapy Department, Western Infirmary, Glasgow, for access to radiation sources and helpful advice.

scholarly journals An Overview of Rare Earth Ores Beneficiation in Vietnam

2021 ◽  
Vol 1 (2) ◽  
Author(s):  
Thi Kim Dung NHU ◽  
Van Luan PHAM ◽  
Thi Chinh VU ◽  
Van Duoc TRAN
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Magnetic Materials ◽  
Animal Feed ◽  
Rare Earth Metals ◽  
Earth’S Crust ◽  
Research Projects ◽  
Essential Minerals ◽  
Different Types ◽  
Earth's Crust

Rare earth metals are used in electricity, electronics, nuclear, optics, space, metallurgy,superconducting and super magnetic materials, glass and ceramics, and agriculture. Some rare earthelements are added to fertilizers for crops and some trials for animal feed. Rare earth elements, exceptfor radioactive promethium, are relatively abundant in the earth's crust. Vietnam has a tremendous rareearth potential, distributed mainly in the Northwest, including Nam Xe, Dong Pao, Muong Hum, andYen Bai. There are many research projects on rare earth ores of different types globally, but the focus ismainly on the essential minerals, including monazite, xenotime, and bastnaesite. This report summarizesresearch data on rare earth ore intending to produce a general assessment of rare earth ore and itsbeneficiation technology in Vietnam.

scholarly journals Investigation of the Structural and Magnetic Properties of the Light Rare Earth Elements and Their Intermetallic Compounds

1988 ◽  
Vol 41 (2) ◽  
pp. 155 ◽  
Author(s):  
DC Creagh
Keyword(s):  
Magnetic Properties ◽  
Rare Earth ◽  
Rare Earth Elements ◽  
Intermetallic Compounds ◽  
Light Rare Earth ◽  
X Ray Diffraction ◽  
X Ray ◽  
Radiation Sources ◽  
Structural And Magnetic Properties ◽  
Light Rare Earth Elements

The experimental requirements for the investigation of the structural and magnetic properties of the light rare earth elements and their intermetallic compounds at synchrotron radiation sources are discussed. Experimental techniques considered include X-ray topography, energy dispersive X-ray diffraction and X-ray powder diffraction.

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