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

Cerium-activated rare-earth orthophosphate and double-phosphate scintillators for x- and gamma-ray detection

2004 ◽  
Author(s):  
Lynn A. Boatner ◽  
L. A. Keefer ◽  
J. M. Farmer ◽  
Dariusz Wisniewski ◽  
Andrjez J. Wojtowicz
Keyword(s):  
Rare Earth ◽  
Gamma Ray ◽  
Double Phosphate

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

KLi2RE(BO3)2 (RE = Dy, Ho, Er, Tm, Yb, and Y): Structural, Spectroscopic, And Thermogravimetric Studies on a Series of Mixed-Alkali Rare-Earth Orthoborates

2020 ◽  
Vol 59 (24) ◽  
pp. 18214-18224
Author(s):  
Pengyun Chen ◽  
M. Mangir Murshed ◽  
Michael Fischer ◽  
Thomas Frederichs ◽  
Thorsten M. Gesing
Keyword(s):  
Rare Earth ◽  
Mixed Alkali ◽  
Thermogravimetric Studies

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.

Interactions of Simulated High Level Waste (HLW) Calcine with Alkali Borosilicate Glass

2003 ◽  
Vol 807 ◽  
Author(s):  
S. Morgan ◽  
R. J. Hand ◽  
N. C. Hyatt ◽  
W. E. Lee
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Borosilicate Glass ◽  
Glass Frit ◽  
High Level Waste ◽  
Second Stage ◽  
Mixed Alkali ◽  
High Level ◽  
Simulated High Level Waste ◽  
Fuel Reprocessing

ABSTRACTThis study looks at the interactions between simulated calcined high level waste from fuel reprocessing and mixed alkali borosilicate glass frit in the early stages of melting, and the possibility of the formation of yellow phase during these stages. Simulant “calcine” from a full scale inactive trial (Magnox: oxide “blend” 25:75) was pre-mixed with alkali borosilicate glass, to achieve a 25wt% waste loading, and melted at 1050°C at various times. It is shown that dissolution occurs in two separate stages; the first involves formation of a low density CsLiMoO4 fluid, which separates and forms a yellow/green layer on the surface of the melt, accompanied by some dissolution of rare- earth elements (Nd, Ce, Gd) and Zr from the waste into the glass matrix. The second stage entails more extensive migration of these rare-earth elements into the glass, and the disappearance of the surface layer on the melt. The glass appears more homogenized at the later stages of melting, but still contains undissolved particles of calcine after 16 minutes.

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