Isotope Fractionation due to Sedimentation of Atoms in Centrifuged Indium-Lead Alloy

2009 ◽  
Vol 289-292 ◽  
pp. 63-68 ◽  
Author(s):  
Masao Ono ◽  
Yusuke Iguchi ◽  
Satoru Okayasu ◽  
Fumitaka Esaka ◽  
Katsura Kobayashi ◽  
...  
Keyword(s):  
Gravitational Field ◽  
Centrifugal Force ◽  
Isotope Ratio ◽  
Isotope Fractionation ◽  
Mass Difference ◽  
Atomic Scale ◽  
Self Diffusion ◽  
Isotope Abundance ◽  
Secondary Ion ◽  
Negative Gradient

The atomic-scale graded structure of In-Pb alloy was formed by an ultracentrifuge under a gravitational field of 0.81 x 106 g for 100 hours at 150 °C in solid state. The isotope ratio measurements were performed on the centrifuged sample with secondary ion mass spectrometer (SIMS, CAMECA IMS-6f). 206Pb/208Pb and 207Pb/208Pb isotope ratio changed with negative gradient in the direction of centrifugal force approximately 1.5% and 0.8%, respectively. There was a tendency that the heavy 208Pb isotope abundance increased and the light 206Pb isotope abundance decreased in the direction of centrifugal force. Three-isotope diagram of 206Pb/208Pb versus 207Pb/208Pb proved that the isotope fractionation depends on the isotopic mass difference. These results showed that a strong gravitational field not only affected the inter-diffusion but also the self-diffusion in this alloy by causing isotope fractionation effect, which was dependent on the mass-difference.

scholarly journals Transport and Electromechanical Properties of Ca3TaGa3Si2O14 Piezoelectric Crystals at Extreme Temperatures

MRS Advances ◽  
2019 ◽  
Vol 4 (09) ◽  
pp. 515-521
Author(s):  
Yuriy Suhak ◽  
Ward L. Johnson ◽  
Andrei Sotnikov ◽  
Hagen Schmidt ◽  
Holger Fritze
Keyword(s):  
Secondary Ion Mass Spectrometry ◽  
Tone Burst ◽  
Total Conductivity ◽  
Transport Mechanisms ◽  
Electromechanical Properties ◽  
Self Diffusion ◽  
Oxygen Ion ◽  
Piezoelectric Strain ◽  
Secondary Ion ◽  
Diffusion Profiles

ABSTRACTTransport mechanisms in structurally ordered piezoelectric Ca3TaGa3Si2O14 (CTGS) single crystals are studied in the temperature range of 1000-1300 °C by application of the isotope 18O as a tracer and subsequent analysis of diffusion profiles of this isotope using secondary ion mass spectrometry (SIMS). Determined oxygen self-diffusion coefficients enable calculation of oxygen ion contribution to the total conductivity, which is shown to be small. Since very low contributions of the cations have to be expected, the total conductivity must be dominated by electron transport. Ion and electron conductivities are governed by different mechanisms with activation energies (1.9±0.1) eV and (1.2±0.07) eV, respectively. Further, the electromechanical losses are studied as a function of temperature by means of impedance spectroscopy on samples with electrodes and a contactless tone-burst excitation technique. At temperatures above 650 °C the conductivity-related losses are dominant. Finally, the operation of CTGS resonators is demonstrated at cryogenic temperatures and materials piezoelectric strain constants are determined from 4.2 K to room temperature.

scholarly journals Gd Matrix Effects on Eu Isotope Fractionation in Geological Rocks Using MC-ICP-MS: Optimizing Europium Isotope Ratio Measurements in Geological Samples

2021 ◽  
Author(s):  
Seung-Gu Lee ◽  
Tsuyoshi Tanaka
Keyword(s):  
Isotope Ratio ◽  
Isotope Fractionation ◽  
Matrix Effects ◽  
Internal Standard ◽  
Geological Samples ◽  
Chemical Reagent ◽  
True Value ◽  
Icp Ms ◽  
Silicate Rocks ◽  
Isotope Ratio Measurements

<p></p><p>Eu has only two isotopes (151Eu and 153 Eu). Eu and Gd are one of the rare earth elements that are very difficult to completely separate from each other. Eu isotope ratio can be determined by MC-ICP-MS using internal Sm or Gd spikes to correct for mass discrimination. NIST3117a ultrapure chemical reagent shows almost no Eu isotope fractionation regardless of the kind of normalization isotope pair. However, Eu isotope ratio in the silicate rocks was effected by Gd matrix during MC-ICP-MS measurement if a trace amount of Gd impurity remains in the purified Eu fraction. In this report, we tried to determine optimizing conditions for precise and accurate Europium isotope ratio measurements in geological samples using MC-ICP-MS. The pure Eu fraction with almost no Gd matrix separated from geological samples and NIST3117a ultrapure chemical reagent show almost same degree of Eu isotope fractionation regardless of the kind of normalization isotope pair. However, Eu isotope ratio in the silicate rocks was effected by Gd matrix during MC-ICP-MS measurement using if 154 Gd interference relative to 154 Sm as internal standard is more than ca. 0.1%. Particularly, highly fractionated granite and high silica volcanic rock with extremely low Eu concentration compared to Gd require high – purity Eu separation with a high recovery rate to obtain the true value of the Eu isotope fractionation in the geological rocks. <br></p><br><p></p>

Sedimentation of Impurity Atoms in InSb Semiconductor under a Strong Gravitational Field

2009 ◽  
Vol 289-292 ◽  
pp. 319-322 ◽  
Author(s):  
Yusuke Iguchi ◽  
Masao Ono ◽  
Satoru Okayasu ◽  
Tsutomu Mashimo
Keyword(s):  
Gravitational Field ◽  
Vapor Deposition ◽  
Physical Vapor Deposition ◽  
Atomic Scale ◽  
Semiconductor Materials ◽  
Strong Gravitational Field ◽  
Impurity Atoms ◽  
Graded Structure ◽  
Alloys And Compounds ◽  
Crystal Wafer

An atomic-scale graded structure has been formed by sedimentation of substitutional atoms under an ultra-strong gravitational field of 1 million G level in alloys and compounds. In this study, we investigate the sedimentation of impurity atoms in semiconductor materials under a strong gravitational field. High-temperature ultracentrifuge experiments (0.59×106 G, 400°C, 60 hours) have been performed on an InSb single crystal wafer which surface was coated with Ge by means of Physical Vapor Deposition (PVD). It was observed that the penetration depth of diffused Ge atoms under the gravitational field was several times larger than under terrestrial field at the same temperatures.

A tandem-column extraction chromatography for Nd separation: minimizing mass-independent isotope fractionation for ultrahigh-precision Nd isotope-ratio analysis

2022 ◽  
Author(s):  
Da Wang ◽  
Richard Carlson
Keyword(s):  
Solar System ◽  
Extraction Chromatography ◽  
Isotope Ratio ◽  
Isotope Fractionation ◽  
Ratio Analysis ◽  
Nd Isotope ◽  
Planetary Differentiation ◽  
Isotope Ratio Analysis ◽  
Isotope System ◽  
Column Extraction

The short-lived 146Sm-142Nd isotope system traces key early planetary differentiation processes that occurred during the first 500 million-years of solar system history. The variations of 142Nd/144Nd in terrestrial samples, typically...

6. Measuring isotopes

2016 ◽  
Author(s):  
Rob Ellam
Keyword(s):  
Inductively Coupled Plasma ◽  
Isotope Ratio ◽  
Ion Source ◽  
Routine Laboratory ◽  
Mass Filter ◽  
Mass Spectrometers ◽  
Inductively Coupled ◽  
Gas Source ◽  
Essential Components ◽  
Secondary Ion

Mass spectrometers have become routine laboratory instruments in many disciplines. ‘Measuring isotopes: mass spectrometers’ concentrates on those used to quantify the abundance of different isotopes—gas source isotope ratio, thermal ionization, inductively coupled plasma, and secondary ion mass spectrometers. A mass spectrometer can be used to quantify the concentration of a particular element by monitoring an isotope of that element not overlapped by isotopes of other elements. All mass spectrometers have three essential components: an ion source, a mass filter, and a detector. There are two main types of detector: Faraday detectors measure large signals and a variant of photomultiplier tubes measures small isotope signals.

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