Monitoring and quantitative evaluation of Faraday cup deterioration in a thermal ionization mass spectrometer using multidynamic analyses of laboratory standards

2021 ◽  
Author(s):  
Yankun Di ◽  
Zefeng Li ◽  
Yuri Amelin
Keyword(s):  
Isotopic Ratio ◽  
Ionization Mass ◽  
Mass Spectrometers ◽  
Faraday Cup ◽  
Long Term Stability ◽  
Isotopic Analyses ◽  
Thermal Ionization Mass Spectrometer ◽  
Cross Calibration ◽  
Multiple Detectors

Accurate and precise isotopic ratio determinations using multi-collector (MC) mass spectrometers rely on accurate cross-calibration and long-term stability of the efficiencies of the multiple detectors. Isotopic analyses at part per...

scholarly journals Strontium and 87Sr/86Sr isotopic ratio of ground brines in the northeastern Angara-Lena artesian basin

2021 ◽  
Vol 44 (2) ◽  
pp. 98-105
Author(s):  
L. P. Alekseeva ◽  
S. V. Alekseev
Keyword(s):  
Isotopic Composition ◽  
High Salinity ◽  
Isotopic Ratio ◽  
Sedimentary Basins ◽  
Formation Processes ◽  
Salt Composition ◽  
Strontium Content ◽  
Mass Spectrometers ◽  
Ionic Salt

The purpose of this study is to identify the major formation processes of the ionic and isotopic composition of chloride brines in the sedimentary basins of the Siberian platform. The object and subject of research are deep-seated strong, very strong and extremely saturated brines as well as their strontium content and the ratio of Sr stable isotopes. The groundwater ionic-salt composition was determined by traditional methods (titrimetric, gravimetric, flame photometry), the 87Sr/86Sr isotopic ratio was measured using mass-spectrometers (Irkutsk, Russia and Canada). The brines lying at the depth of 1500–3000 m were tapped and classified into saline and subsalt hydrogeological formations. Their feature is high salinity (385–530 g/L) and high content of strontium (2.3–7 g/L). The 87Sr/86Sr isotopic ratio ranges from 0.708 to 0.713062. By isotopic composition most of the brine samples are close to the waters of the Vendian-Cambrian paleoocean. However, some brine samples from the subsalt part of the sedimentary section of the basin are significantly enriched in the isotope 87Sr compared to the paleoocean waters and other samples. It could be due to the substantial input of 87Sr into the brines during the long-term interaction of groundwater with the host Lower Cambrian sandstones.

In Situ Isotopic Analysis of Uraninite Microstructures from the Oklo-Okélobondo Natural Fission Reactors, Gabon

2002 ◽  
Vol 713 ◽  
Author(s):  
Mostafa Fayek ◽  
Keld A. Jensen ◽  
Rodney C. Ewing ◽  
Lee R. Riciputi
Keyword(s):  
Spatial Resolution ◽  
Spent Nuclear Fuel ◽  
Spatial Scales ◽  
Ionization Mass ◽  
Near Surface ◽  
Chain Reactions ◽  
Isotopic Analyses ◽  
Fission Reactors

ABSTRACTUranium deposits can provide important information on the long-term performance of radioactive waste forms because uraninite (UO2+X) is similar to the UO2 in spent nuclear fuel. The Oklo-Okélobondo U-deposits, Gabon, serve as natural laboratory where the long-term (hundreds to billions of years) migration of uranium and other radionuclides can be studied over large spatial scales (nm to km). The natural fission reactors associated with the Oklo- Okélobondo U-deposits occur over a range of depths (100 to 400 m) and provide a unique opportunity to study the behavior of uraninite in near surface oxidizing environments versus more reducing conditions at depth. Previously, it has been difficult to constrain the timing of interaction between U-rich minerals and post-depositional fluids. These problems are magnified because uraninite is susceptible to alteration, it continuously self-anneals radiation damage, and because these processes are manifested at the nm to μm scale. Uranium, lead and oxygen isotopes can be used to study fluid-uraninite interaction, provided that the analyses are obtained on the micro-scale. Secondary ionization mass spectrometry (SIMS) permits in situ measurement of isotopic ratios with a spatial resolution on the scale of a few μm. Preliminary U-Pb results show that uraninite from all reactor zones are highly discordant with ages aaproaching the timing of fission chain reactions (1945±50 Ma) and resetting events at 1180±47 Ma and 898±46 Ma. Oxygen isotopic analyses show that uraninite from reactors that occur in near surface environments (δ18O= −14.4‰ to −8.5‰) have reacted more extensively with groundwater of meteoric origin relative to reactors located at greater depths (μ18O= −10.2‰ to −7.3‰). This study emphasizes the importance of using in situ high spatial resolution analysis techniques for natural analogue studies.

scholarly journals Instrument Development: Chinese Radiometric Benchmark of Reflected Solar Band Based on Space Cryogenic Absolute Radiometer

2020 ◽  
Vol 12 (17) ◽  
pp. 2856
Author(s):  
Xin Ye ◽  
Xiaolong Yi ◽  
Chao Lin ◽  
Wei Fang ◽  
Kai Wang ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Measurement Accuracy ◽  
Signal To Noise Ratio ◽  
Imaging Spectrometer ◽  
Term Stability ◽  
Long Term Stability ◽  
Remote Sensors ◽  
Cross Calibration ◽  
Transfer Chain

Low uncertainty and long-term stability remote data are urgently needed for researching climate and meteorology variability and trends. Meeting these requirements is difficult with in-orbit calibration accuracy due to the lack of radiometric satellite benchmark. The radiometric benchmark on the reflected solar band has been under development since 2015 to overcome the on-board traceability problem of hyperspectral remote sensing satellites. This paper introduces the development progress of the Chinese radiometric benchmark of the reflected solar band based on the Space Cryogenic Absolute Radiometer (SCAR). The goal of the SCAR is to calibrate the Earth–Moon Imaging Spectrometer (EMIS) on-satellite using the benchmark transfer chain (BTC) and to transfer the traceable radiometric scale to other remote sensors via cross-calibration. The SCAR, which is an electrical substitution absolute radiometer and works at 20 K, is used to realize highly accurate radiometry with an uncertainty level that is lower than 0.03%. The EMIS, which is used to measure the spectrum radiance on the reflected solar band, is designed to optimize the signal-to-noise ratio and polarization. The radiometric scale of the SCAR is converted and transferred to the EMIS by the BTC to improve the measurement accuracy and long-term stability. The payload of the radiometric benchmark on the reflected solar band has been under development since 2018. The investigation results provide the theoretical and experimental basis for the development of the reflected solar band benchmark payload. It is important to improve the measurement accuracy and long-term stability of space remote sensing and provide key data for climate change and earth radiation studies.

The Flexible Microtube Plasma as Post-Ionization Source for Cholesterol in nano-Electrospray Mass Spectrometry

2021 ◽  
Author(s):  
Daniel Foest ◽  
Alexander Knodel ◽  
Robert Ahrends ◽  
Cristina Coman ◽  
Joachim Franzke ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Dynamic Range ◽  
Standard Addition ◽  
Polar Compounds ◽  
Ionization Mass ◽  
Ionization Source ◽  
Long Term Stability ◽  
Novel Approach

Cholesterol serves as a biomarker in clinical- and life-sciences. The determination of abnormal levels can indicate several types of human diseases. However, the low polarity of free cholesterol makes it hardly accessible by (nano) electrospray ionization mass spectrometry (nESI-MS). As novel approach, the flexible microtube plasma (FμTP) for post-ionization allows the determination of low-polar compounds like cholesterol in combination with nESI-MS. Focusing on the analytical performance, the activated post-ionization leads to an increased cholesterol signal by a factor of 22. The repeatability and long-term stability could be successful evaluated by using a complex liver extract. Via the method of standard addition, a linear dynamic range of 1.7 orders of magnitude, a minimum detectability of 3.71 mg/L and a high accuracy (deviation: − 8.11 %) is demonstrated proofing the FμTP-nESI-MS as an excellent approach for a derivatization-free determination of cholesterol without the necessity of high-resolution Orbitrap devices or enhanced MS acquisition-methods.

scholarly journals Cross calibration of the Siemens mMR: easily acquired accurate PET phantom measurements, long term stability and reproducibility

2015 ◽  
Vol 2 (S1) ◽  
Author(s):  
Sune H Keller ◽  
Bjorn Jakoby ◽  
Adam Espe Hansen ◽  
Susanne Svalling ◽  
Thomas L Klausen
Keyword(s):  
Term Stability ◽  
Long Term Stability ◽  
Phantom Measurements ◽  
Cross Calibration

scholarly journals Cross-calibration of the Siemens mMR: easily acquired accurate PET phantom measurements, long-term stability and reproducibility

2016 ◽  
Vol 3 (1) ◽  
Author(s):  
Sune H. Keller ◽  
Björn Jakoby ◽  
Susanne Svalling ◽  
Andreas Kjaer ◽  
Liselotte Højgaard ◽  
...  
Keyword(s):  
Term Stability ◽  
Long Term Stability ◽  
Phantom Measurements ◽  
Cross Calibration

scholarly journals Radiometric flight results from the HyperSpectral Imager for Climate Science (HySICS)

2017 ◽  
Vol 6 (1) ◽  
pp. 169-191 ◽  
Author(s):  
Greg Kopp ◽  
Paul Smith ◽  
Chris Belting ◽  
Zach Castleman ◽  
Ginger Drake ◽  
...  
Keyword(s):  
Near Infrared ◽  
Solar Spectrum ◽  
Climate Science ◽  
Trend Detection ◽  
Imaging Spectrometer ◽  
Long Term Stability ◽  
Order Of Magnitude ◽  
Lunar Observations ◽  
Cross Calibration

Abstract. Long-term monitoring of the Earth-reflected solar spectrum is necessary for discerning and attributing changes in climate. High radiometric accuracy enables such monitoring over decadal timescales with non-overlapping instruments, and high precision enables trend detection on shorter timescales. The HyperSpectral Imager for Climate Science (HySICS) is a visible and near-infrared spatial/spectral imaging spectrometer intended to ultimately achieve ∼ 0.2 % radiometric accuracies of Earth scenes from space, providing an order-of-magnitude improvement over existing space-based imagers. On-orbit calibrations from measurements of spectral solar irradiances acquired by direct views of the Sun enable radiometric calibrations with superior long-term stability than is currently possible with any manmade spaceflight light source or detector. Solar and lunar observations enable in-flight focal-plane array (FPA) flat-fielding and other instrument calibrations. The HySICS has demonstrated this solar cross-calibration technique for future spaceflight instrumentation via two high-altitude balloon flights. The second of these two flights acquired high-radiometric-accuracy measurements of the ground, clouds, the Earth's limb, and the Moon. Those results and the details of the uncertainty analyses of those flight data are described.

scholarly journals Radiometric flight results from the HyperSpectral Imager for Climate Science (HySICS)

2016 ◽  
Author(s):  
Greg Kopp ◽  
Paul Smith ◽  
Chris Belting ◽  
Ginger Drake ◽  
Joey Espejo ◽  
...  
Keyword(s):  
Near Infrared ◽  
Solar Spectrum ◽  
Climate Science ◽  
Trend Detection ◽  
Imaging Spectrometer ◽  
Long Term Stability ◽  
Order Of Magnitude ◽  
Lunar Observations ◽  
Cross Calibration

Abstract. Long-term monitoring of the Earth-reflected solar-spectrum is necessary for discerning and attributing changes in climate. High radiometric-accuracy enables such monitoring over decadal timescales with non-overlapping instruments, and high precision enables trend detection on shorter timescales. The Hyperspectral Imager for Climate Science (HySICS) is a visible and near-infrared spatial/spectral imaging-spectrometer intended to ultimately achieve ~ 0.2 % radiometric accuracies of Earth scenes from space, providing an order-of-magnitude improvement over existing space-based imagers. On-orbit calibrations from measurements of spectral solar irradiances acquired by direct views of the Sun enable radiometric calibrations with superior long-term stability than currently possible with any manmade spaceflight light-source or detector. Solar- and lunar-observations enable in-flight focal-plane-array flat-fielding and other instrument calibrations. The HySICS has demonstrated this solar cross-calibration technique for future spaceflight instrumentation via two high-altitude balloon flights. The second of these two flights acquired high radiometric-accuracy measurements of the ground, clouds, the Earth's limb, and the Moon. Those results and the details of the uncertainty analyses of those flight data are described.

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