A cavity ion source for high-ionization efficiency neodymium isotope-ratio analyses in the geosciences

2020 ◽  
Vol 35 (10) ◽  
pp. 2337-2350
Author(s):  
Jesse R. Reimink ◽  
Richard W. Carlson ◽  
Timothy D. Mock
Keyword(s):  
Isotope Ratio ◽  
Isotope Ratios ◽  
Ion Beams ◽  
Ion Source ◽  
Ion Sources ◽  
Ionization Efficiency ◽  
Nd Isotope ◽  
Isotope Data ◽  
High Ionization

Precision in Nd isotope ratios measurements is dominated by the number of ions counted. We show that cavity ion sources can provide ion beams capable of producing much more precise Nd isotope data.

scholarly journals Ionization Efficiency in a Hot Flat Disc-Shaped Cavity

2020 ◽  
Vol 11 (2) ◽  
pp. 132-139
Author(s):  
M. Turek
Keyword(s):  
Isotope Separation ◽  
Ion Source ◽  
Ion Sources ◽  
Ionization Efficiency ◽  
Total Ionization ◽  
High Ionization ◽  
On Line ◽  
New Type ◽  
Scientists And Engineers ◽  
Separation Devices

Hot cavity ion sources of different kinds are widely used in nuclear and mass spectroscopy, especially in on-line isotope separation devices attracting attention of scientists and engineers looking for high ionization efficiency, robustness and beam purity. In the paper a new type of hot ionizer cavity is proposed: namely cavity having the shape of a flat disc, which may be especially suitable for short-lived nuclides to be ionized.A numerical model of the ion source is presented in the paper. The particle tracking code takes into account ionization at hot surfaces and enables modeling of both flat disc cavity and standard elongated cavity ionizers. The code enables calculation of total ionization efficiency and is suitable for stable and long-lived nuclides.Influence of the flat disc cavity geometry (thickness and radius) and its temperature on total ionization efficiency was considered – it was shown that the efficiency increases with cavity radius due to the growing number of particle-wall collisions. This effect may be important in the case of the hard-to-ionize nuclides.The optimal ionizer geometry is characterized by 90 % efficiency, even for substances with rather low ionization coefficient (of order 0.05). The role played by the size of the extraction opening is explained – it is demonstrated that the ionization efficiency increases due to the opening radius reduction. It is also proven that extraction voltage of 1–2 kV is sufficient to maintain optimal ionizer efficiency. 

scholarly journals System for Measuring Emittance Characteristics of Ion Sources

2020 ◽  
Keyword(s):  
Beam Energy ◽  
Ion Beam ◽  
Electronic System ◽  
Ion Beams ◽  
Ion Source ◽  
Ion Sources ◽  
Raspberry Pi ◽  
Current Profile ◽  
Voltage Amplifier ◽  
Wide Range

The article presents the results of the development of a system for measuring emittance characteristics of ion sources studied at the IAP NAS of Ukraine with the aim of obtaining the ion beams with a high brightness. The emittance measurement system is based on the scheme of an electrostatic scanner and consists of two main parts: the scanner, which moves in the direction perpendicular to the beam axis using a stepper motor, and the electronic system of control, processing and data acquisition. The electronic system contains a Raspberry pi 3B microcomputer, precision DAC/ADCs, the high-voltage amplifier of a scanning voltage up to ±500 V on deflection plates of the scanner and a wide range current integrator. The determination of the emittance consists in measuring the ion beam intensity distribution when the scanner moves along the x-coordinate and the electrostatic scanning along the x´ angle. The obtained two-dimensional data array allows determining the main characteristics of ion beam: geometric 90% emittance, the root mean square (rms) emittance, the Twiss parameters and phase ellipse of rms emittance, the beam current profile and the angle current density distribution. To test the performance and functionality of the system, the emittance characteristics of the penning type ion source were measured. The working gas was helium, and the beam energy varied within 7–15 keV. At 13 keV of beam energy the following emittances of the He+ ions beam was obtained: 90% emittance is 30 π∙mm∙mrad, rms emittance is 8.4 mm∙mrad, and the normalized rms emittance is equal to 0.022 mm∙mrad. The developed system for measuring the emittance of the ion beams is characterized by a short measurement time of 10-15 minutes.

scholarly journals Novel Approaches for Intensifying Negative C60 Ion Beams Using Conventional Ion Sources Installed on a Tandem Accelerator

2020 ◽  
Vol 4 (1) ◽  
pp. 13 ◽  
Author(s):  
Atsuya Chiba ◽  
Aya Usui ◽  
Yoshimi Hirano ◽  
Keisuke Yamada ◽  
Kazumasa Narumi ◽  
...  
Keyword(s):  
High Intensity ◽  
Energy Region ◽  
Electron Attachment ◽  
Ion Beams ◽  
Ion Source ◽  
Ion Sources ◽  
Current Intensity ◽  
Tandem Accelerator ◽  
Accelerator Facility ◽  
Novel Approaches

We developed novel methods for producing negative C60 ion beams at the accelerator facility Takasaki Ion Accelerators for Advanced Radiation Application (TIARA) to increase the current intensity of swift C60 ion beams accelerated to the MeV energy region using a tandem accelerator. We produced negative C60 ion beams with an intensity of 1.3 µA, which is several tens of thousands of times greater than the intensity of beams produced using conventional methods based on the Cs sputtering process. These beams were obtained by temporarily adding an ionization function based on electron attachment to an existing ion source that is widely used in tandem accelerators. The high-intensity swift C60 ion beams can be made available relatively easily to institutes that have tandem accelerators and ion sources of the type used at TIARA because there is no need to change existing ion sources or install new ones.

scholarly journals Country-rock contamination of marginal mafic granulites bordering the Nain Plutonic Suite: implications for mobilization of Sr during high-grade contact metamorphism

1999 ◽  
Vol 36 (6) ◽  
pp. 985-997 ◽  
Author(s):  
K R Royse ◽  
S R Noble ◽  
J Tarney ◽  
A C Cadman
Keyword(s):  
Country Rock ◽  
Isotope Ratios ◽  
Contact Metamorphism ◽  
High Grade ◽  
Sr Isotope ◽  
Nd Isotope ◽  
Isotope Data ◽  
Mineral Phases ◽  
Nain Plutonic Suite

The marginal mafic granulites that locally border the Nain Plutonic Suite (NPS) have a range of initial Nd-isotope ratios that overlap with that of the NPS anorthosites and associated Nain dykes. The similarity in Nd-isotope data suggests that gneissic Archaean country rocks have contaminated all the anorthosites, marginal mafic granulites, and dykes. Sr-isotope data for the mafic granulites and dykes support a country rock contamination scenario but preclude wholesale assimilation of rocks such as the host Archaean tonalite gneisses as the sole contaminant. Initial epsilonSr values of +10 to +403 and +0.9 to +242 for the mafic granulites and dykes, respectively, are significantly higher than values for NPS country rocks examined thus far. The elevated initial εSr values are therefore interpreted to result from the introduction of radiogenic Sr into the granulites and dykes via Sr-rich fluids, generated by the breakdown of Rb-rich mineral phases such as biotite in the country rocks during NPS.

Neodymium isotope ratio measurements by CE-MC-ICPMS: investigation of isotopic fractionation and evaluation of analytical performances

2017 ◽  
Vol 32 (11) ◽  
pp. 2271-2280 ◽  
Author(s):  
Benoît Martelat ◽  
Laurent Vio ◽  
Hélène Isnard ◽  
Jérôme Simonnet ◽  
Térence Cornet ◽  
...  
Keyword(s):  
Isotope Ratio ◽  
Isotopic Fractionation ◽  
Isotope Ratios ◽  
Nd Isotope ◽  
Online Measurements ◽  
Isotope Ratio Measurements

This study demonstrated the feasibility of precise online measurements of Nd isotope ratios by EC-MC-ICPMS.

Plagioclase weathering by mycorrhizal plants in a Ca-depleted catchment, inferred from Nd isotope ratios and REE composition

2017 ◽  
Vol 51 (6) ◽  
pp. 537-550
Author(s):  
Tasuku Akagi ◽  
Tomohiro Miura ◽  
Rie Takada ◽  
Kazuo Watanabe
Keyword(s):  
Isotope Ratios ◽  
Nd Isotope ◽  
Mycorrhizal Plants

Authenticity of sugar – Identification of plant source and determination of geographical origin of sucrose

2015 ◽  
pp. 40-43 ◽  
Author(s):  
Andreas G. Degenhardt
Keyword(s):  
Metabolic Pathways ◽  
Isotope Ratio ◽  
Geographical Origin ◽  
Hydrological Cycle ◽  
Isotope Ratios ◽  
Saccharum Officinarum ◽  
Mass Spectrometric ◽  
C3 And C4 Plants ◽  
Plant Source

The isotope ratios of water, organic matter and micronutrients from food are dependent on the circumstances and sites of their origin and production. Analytical methods, based on mass spectrometry, are established for routine determination of isotopes. Differentiation between metabolic pathways of C3 and C4 plants is realizable by determination 13C/12C ratios which can distinguish and identify sucrose from pure beet (Beta vulgaris) and pure cane (Saccharum officinarum). Influenced by the worldwide hydrological cycle the isotope ratios of 2H/1H and 18O/16O vary systematically, the variations give information about geographical origin. The exemplarily determination of authenticity is demonstrated by using mass spectrometric isotope ratio evaluation for identification of plant source and geographical origin with the help of selected sugar samples with known origin.

Resonant Ionization Laser Ion Source for Radioactive Ion Beams

2009 ◽  
Author(s):  
Y. Liu ◽  
J. R. Beene ◽  
T. Gottwald ◽  
C. C. Havener ◽  
C. Mattolat ◽  
...  
Keyword(s):  
Ion Beams ◽  
Ion Source ◽  
Radioactive Ion Beams ◽  
Laser Ion Source ◽  
Resonant Ionization

New approaches to crustal evolution studies and the origin of granitic rocks: what can the Lu-Hf and Re-Os isotope systems tell us?

1996 ◽  
Vol 87 (1-2) ◽  
pp. 339-352 ◽  
Author(s):  
Clark M. Johnson ◽  
Steven B. Shirey ◽  
Karin M. Barovich
Keyword(s):  
Continental Crust ◽  
Isotope Ratios ◽  
Granitic Rocks ◽  
Nd Isotope ◽  
Volcanic Arcs ◽  
Depleted Mantle ◽  
Os Isotopes ◽  
Isotope System ◽  
Os Isotope

ABSTRACT:The Lu-Hf and Re-Os isotope systems have been applied sparsely to elucidate the origin of granites, intracrustal processes and the evolution of the continental crust. The presence or absence of garnet as a residual phase during partial melting will strongly influence Lu/Hf partitioning, making the Lu–Hf isotope system exceptionally sensitive to evaluating the role of garnet during intracrustal differentiation processes. Mid-Proterozoic (1·1–1·5Ga ) ‘anorogenic’ granites from the western U.S.A. appear to have anomalously high εHf values, relative to their εNd values, compared with Precambrian orogenic granites from several continents. The Hf-Nd isotope variations for Precambrian orogenic granites are well explained by melting processes that are ultimately tied to garnet-bearing sources in the mantle or crust. Residual, garnet-bearing lower and middle crust will evolve to anomalously high εHf values over time and may be the most likely source for later ‘anorogenic’ magmas. When crustal and mantle rocks are viewed together in terms of Hf and Nd isotope compositions, a remarkable mass balance is apparent for at least the outer silicate earth where Precambrian orogenic continental crust is the balance to the high-εHf depleted mantle, and enriched lithospheric mantle is the balance to the low-εHf depleted mantle.Although the continental crust has been envisioned to have exceptionally high Re/Os ratios and very radiogenic Os isotope compositions, new data obtained on magnetite mineral separates suggest that some parts of the Precambrian continental crust are relatively Os-rich and non-radiogenic. It remains unclear how continental crust may obtain non-radiogenic Os isotope ratios, and these results have important implications for Re-Os isotope evolution models. In contrast, Phanerozoic batholiths and volcanic arcs that are built on young mafic lower crust may have exceptionally radiogenic Os isotope ratios. These results highlight the unique ability of Os isotopes to identify young mafic crustal components in orogenic magmas that are essentially undetectable using other isotope systems such as O, Sr, Nd and Pb.

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