scholarly journals Gamma-ray spectrometric and semiquantitative spectrographic analytical data of the thorium and rare-earth disseminated deposits in the southern Bear Lodge Mountains, Wyoming

1980 ◽  
Author(s):  
Mortimer Hay Staatz ◽  
Nancy M. Conklin ◽  
Carl M. Bunker ◽  
Charles A. Bush
Keyword(s):  
Rare Earth ◽  
Gamma Ray ◽  
Analytical Data

Rare-earth tri-halides methanol-adduct single-crystal scintillators for gamma ray and neutron detection

2009 ◽  
Author(s):  
L. A. Boatner ◽  
D. J. Wisniewski ◽  
J. S. Neal ◽  
Z. W. Bell ◽  
J. O. Ramey ◽  
...  
Keyword(s):  
Rare Earth ◽  
Single Crystal ◽  
Gamma Ray ◽  
Neutron Detection

Cerium-doped mixed-alkali rare-earth double-phosphate scintillators for x- and gamma-ray detection

2006 ◽  
Author(s):  
John S. Neal ◽  
Lynn A. Boatner ◽  
Merry Spurrier ◽  
Piotr Szupryczynski ◽  
Charles L. Melcher
Keyword(s):  
Rare Earth ◽  
Gamma Ray ◽  
Mixed Alkali ◽  
Double Phosphate

scholarly journals The Site Occupancy Assessment in Beryl Based on Bond-Length Constraints

Minerals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 641
Author(s):  
Bačík ◽  
Fridrichová
Keyword(s):  
Rare Earth ◽  
Bond Length ◽  
Octahedral Site ◽  
Analytical Data ◽  
Site Occupancy ◽  
Site Preference ◽  
Bond Lengths ◽  
Simple Molecules ◽  
Ring Distortion ◽  
Average Bond

The site preference for each cation and site in beryl based on bond-length calculations was determined and compared with analytical data. Tetrahedral SiO4 six-membered rings normally have no substitutions which results from very compact Si4+–O bonds in tetrahedra. Any substitution except Be would require significant tetrahedral ring distortion. The Be tetrahedron should also be negligibly substituted based on the bond-valence calculation; the tetrahedral Li–O bond length is almost 20% larger than Be2+–O. Similar or smaller bond lengths were calculated for Cr3+, V3+, Fe3+, Fe2+, Mn3+, Mg2+, and Al3+, which can substitute for Be but also can occupy a neighboring tetrahedrally coordinated site which is completely vacant in the full Be occupancy. The octahedral site is also very compressed due to dominant Al with short bond lengths; any substitution results in octahedron expansion. There are two channel sites in beryl: the smaller 2b site can be occupied by Na+, Ca2+, Li+, and REE3+ (Rare Earth Elements); Fe2+ and Fe3+ are too small; K+, Cs+, Rb+, and Ba2+ are too large. The channel 2a-site average bond length is 3.38 Å which allows the presence of simple molecules such as H2O, CO2, or NH4 and the large-sized cations-preferring Cs+.

Radioelement distribution in U, Th, Mo, and rare-earth-element pegmatites, skarns, and veins in a portion of the Grenville Province, Ontario and Quebec

1991 ◽  
Vol 28 (1) ◽  
pp. 1-12 ◽  
Author(s):  
David Lentz
Keyword(s):  
Rare Earth ◽  
Rare Earth Element ◽  
Earth Element ◽  
Gamma Ray ◽  
Grenville Province ◽  
Heterogeneous Distribution ◽  
Granitic Pegmatites ◽  
Gamma Ray Spectrometer ◽  
Calcite Veins ◽  
Secondary Enrichment

Gamma-ray spectrometer measurements were obtained at and in the vicinity of 104 of the 124 U, Th, Mo, and rare-earth-element (REE) occurrences examined in the Central Metasedimentary Belt of the Grenville Province. Spatial, temporal, mineralogical, and geochemical relationships among granitic pegmatites, phlogopite – scapolite – Ca pyroxene skarns, and fluorite – apatite – calcite veins hosting U, Th, Mo, and REE minerals indicate a common magmatic–hydrothermal origin. Quartz–feldspar gneisses in the Central Metasedimentary Belt (n = 54) have low abundances of uranium (1–7 ppm) and thorium (4–27 ppm) suggesting that partial melting, fractional crystallization, and volatile phase separation were responsible for the enrichment of uranium (2–37 ppm) and thorium (5–102 ppm) in uncontaminated granitic pegmatites (n = 163) derived during ultrametamorphism. The U/Th ratio is probably inherited from the source quartz–feldspar gneiss protolith and enhanced during fractionation.Average U and Th concentrations and U/Th ratios at numerous localities show significant positive correlations among pegmatites, skarns, and veins, providing further evidence for a related origin. The interaction of the pegmatite-derived hydrothermal fluids with host rocks produced a spectrum of types and styles of alteration, which include (i) hybridization and (or) endoskarnification along pegmatite margins; (ii) marble- and clinopyroxenite-hosted exoskarn; and (iii) fluorite–apatite–calcite veins. The deposition of U, Th, Mo, and REE from the evolving hydrothermal fluid is responsible for the heterogeneous distribution of U, Th, and REE minerals and molybdenite within pegmatites, skarns, and veins at each locality. Secondary enrichment of uranium in association with hematitized sheared pegmatites and veins may be responsible for the observed large variation in U/Th ratios at some sites.

Gamma-Ray Thermoluminescence in Rare-Earth-Activated Y2O3Phosphors

1968 ◽  
Vol 7 (12) ◽  
pp. 1497-1503 ◽  
Author(s):  
Yasuro Ato ◽  
Ryoitiro Huzimura ◽  
Lyuji Ozawa
Keyword(s):  
Rare Earth ◽  
Gamma Ray

Luminescence characterization of gamma-ray-irradiated rare-earth doped BaSO4 and MgSO4 phosphors

2011 ◽  
Vol 46 (12) ◽  
pp. 1372-1375 ◽  
Author(s):  
R.S. Kher ◽  
A.K. Upadhyay ◽  
S.K. Gupta ◽  
S.J. Dhoble ◽  
M.S.K. Khokhar
Keyword(s):  
Rare Earth ◽  
Gamma Ray ◽  
Rare Earth Doped
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