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Lived Radionuclides

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J S Becker – One of the best experts on this subject based on the ideXlab platform.

H J Dietze – One of the best experts on this subject based on the ideXlab platform.

  • laser ablation inductively coupled plasma mass spectrometry for the trace ultratrace and isotope analysis of long Lived Radionuclides in solid samples
    International Journal of Mass Spectrometry, 2000
    Co-Authors: J S Becker, Carola Pickhardt, H J Dietze
    Abstract:

    Abstract The capability of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) for determination of long-Lived Radionuclides in different materials (e.g., in geological samples, high-purity graphite and nonconducting concrete matrix) was investigated. The main problem in the quantification of the analytical results of long-Lived Radionuclides is that (except for geological samples) no suitable standard reference materials are available. Therefore, synthetic laboratory standards (graphite and concrete matrix doped with long-Lived Radionuclides, such as 99Tc, 232Th, 233U, 235U, 237Np, 238U) were prepared and used for quantification purposes in LA-ICP-MS. Different calibration procedures—the correction of analytical results with experimentally determined relative sensitivity coefficients (RSCs), the use of calibration curves and solution calibration by coupling LA-ICP-MS with an ultrasonic nebulizer—were applied for the determination of long-Lived Radionuclides, especially for Th and U in different solid samples. The limits of detection of long-Lived Radionuclides investigated in concrete matrix are determined in the pg g−1 range (e.g., for 237Np-50 pg g−1 in quadrupole LA-ICP-MS; for 233U-1.3 pg g−1 in double-focusing sector field LA-ICP-MS). Results of isotope ratio measurements of Th and U in synthetic laboratory standards and different solid radioactive waste materials of direct analysis on solid samples using LA-ICP-MS are comparable to measurements using the double-focusing sector field ICP-MS after separation of the analyte, even if no possible interference of atomic ions of analyte and molecular ions are expected. Furthermore, LA-ICP-MS allows precise and accurate isotope ratio measurements of Th and U in solid samples. For example, the isotope ratio 234U/238U = 0.000067 in radioactive reactor graphite was determined with a precision of 1.1% relative standard deviation (RSD).

  • ultratrace and isotope analysis of long Lived Radionuclides by inductively coupled plasma quadrupole mass spectrometry using a direct injection high efficiency nebulizer
    Analytical Chemistry, 1999
    Co-Authors: J S Becker, H J Dietze, John A Mclean, Akbar Montaser
    Abstract:

    The direct injection high efficiency nebulizer (DIHEN) was explored for the ultrasensitive determination of long-Lived Radionuclides (226Ra, 230Th, 237Np, 238U, 239Pu, and 241Am) and for precise isotope analysis by inductively coupled plasma mass spectrometry (ICPMS). The DIHEN was used at low solution uptake rates (1−100 μL/min) without a spray chamber. Optimal sensitivity (e.g., 238U, 230 MHz/ppm; 230Th, 190 MHz/ppm; and 239Pu, 184 MHz/ppm) was achieved at low nebulizer gas flow rates (0.16 L/min), high rf power (1450 W), and low solution uptake rates (100 μL/min). The optimum parameters varied slightly for the two DIHENs tested. The detection limits of long-Lived Radionuclides in aqueous solutions varied from 0.012 to 0.11 ng/L. The sensitivity of the DIHEN was improved by a factor of 3 to 5 compared with that of a microconcentric nebulizer (MicroMist used with a minicyclonic spray chamber at a solution uptake rate of 85 μL/min) and a factor of 1.5 to 4 compared with that of a conventional nebulizer (c…

  • determination of long Lived Radionuclides by inductively coupled plasma quadrupole mass spectrometry using different nebulizers
    Journal of Analytical Atomic Spectrometry, 1999
    Co-Authors: Sabine J Becker, Rajiv S Soma, Karen L Sutton, Joseph A Caruso, H J Dietze
    Abstract:

    Different nebulizers (cross-flow, ultrasonic and two microconcentric nebulizers) were used for sample introduction of radioactive solutions into a quadrupole-based inductively coupled plasma mass spectrometer (ICP-QMS). The best sensitivity (from 420 to 850 MHz, which is about one order of magnitude higher in comparison with the cross-flow nebulizer) for long-Lived Radionuclides ( 226 Ra, 230 Th, 237 Np, 238 U and 241 Am) was observed using the ultrasonic nebulizer. However, using the ultrasonic nebulizer, a significantly higher sample size (26-fold) in comparison with the micronebulizers is required. Sample introduction by micronebulization with a small sample size in the low picogram range is the method of choice for the determination of long-Lived Radionuclides. The precision of determination of a 10 ng l –1 concentration was in the low-% range (and sub-% range) for all measurements using different nebulizer types. The detection limits for the determination of long-Lived Radionuclides in aqueous solutions applying the different nebulizers were 0.01-0.6 ng l –1 . The flow injection analysis approach was optimized for isotope dilution analysis of 232 Th (using 20 µl of 5 µg l –1 230 Th) by ICP-QMS. The isotopic abundance ratios of 230 Th- 232 Th isotope mixtures ( 230 Th/ 232 Th=0.01, 0.001 and 0.0001) were determined using a microconcentric nebulizer and 1 µg l –1 Th solutions with a relative external standard deviation of long-term stability measurements (over 20 h) of 0.17, 0.62 and 2.66%, respectively.

Sabine J Becker – One of the best experts on this subject based on the ideXlab platform.

  • inductively coupled plasma mass spectrometry icp ms and laser ablation icp ms for isotope analysis of long Lived Radionuclides
    International Journal of Mass Spectrometry, 2005
    Co-Authors: Sabine J Becker
    Abstract:

    For a few years now inductively coupled plasma mass spectrometry has been increasingly used for precise and accurate determination of isotope ratios of long-Lived Radionuclides at the trace and ultratrace level due to its excellent sensitivity, good precision and accuracy. At present, ICP-MS and also laser ablaablation ICP-MS are applied as powerful analytical techniques in different fields such as the characterization of nuclear materials, recycled and by-products (e.g., spent nuclear fuel or depleted uranium ammunitions), radioactive waste control, in environmental monitoring and in bioassay measurements, in health control, in geochemistry and geochronology. Especially double-focusing sector field ICP mass spectrometers with single ion detector or with multiple ion collector device have been used for the precise determination of long-Lived Radionuclides isotope ratios at very low concentration levels. Progress has been achieved by the combination of ultrasensitive mass spectrometric techniques with effective separation and enrichment procedures in order to improve detection limits or by the introduction of the collision cell in ICP-MS for reducing disturbing interfering ions (e.g., of 129Xe+ for the determination of 129I). This review describes the state of the art and the progress of ICP-MS and laser ablaablation ICP-MS for isotope ratio measurements of long-Lived Radionuclides in different sample types, especially in the main application fields of characterization of nuclear and radioactive waste material, environmental research and health controls.

  • determination of long Lived Radionuclides by inductively coupled plasma quadrupole mass spectrometry using different nebulizers
    Journal of Analytical Atomic Spectrometry, 1999
    Co-Authors: Sabine J Becker, Rajiv S Soma, Karen L Sutton, Joseph A Caruso, H J Dietze
    Abstract:

    Different nebulizers (cross-flow, ultrasonic and two microconcentric nebulizers) were used for sample introduction of radioactive solutions into a quadrupole-based inductively coupled plasma mass spectrometer (ICP-QMS). The best sensitivity (from 420 to 850 MHz, which is about one order of magnitude higher in comparison with the cross-flow nebulizer) for long-Lived Radionuclides ( 226 Ra, 230 Th, 237 Np, 238 U and 241 Am) was observed using the ultrasonic nebulizer. However, using the ultrasonic nebulizer, a significantly higher sample size (26-fold) in comparison with the micronebulizers is required. Sample introduction by micronebulization with a small sample size in the low picogram range is the method of choice for the determination of long-Lived Radionuclides. The precision of determination of a 10 ng l –1 concentration was in the low-% range (and sub-% range) for all measurements using different nebulizer types. The detection limits for the determination of long-Lived Radionuclides in aqueous solutions applying the different nebulizers were 0.01-0.6 ng l –1 . The flow injection analysis approach was optimized for isotope dilution analysis of 232 Th (using 20 µl of 5 µg l –1 230 Th) by ICP-QMS. The isotopic abundance ratios of 230 Th- 232 Th isotope mixtures ( 230 Th/ 232 Th=0.01, 0.001 and 0.0001) were determined using a microconcentric nebulizer and 1 µg l –1 Th solutions with a relative external standard deviation of long-term stability measurements (over 20 h) of 0.17, 0.62 and 2.66%, respectively.

L Zhang – One of the best experts on this subject based on the ideXlab platform.

M Gounelle – One of the best experts on this subject based on the ideXlab platform.

  • massive stars and short Lived Radionuclides in the solar system
    Eas Publications Series, 2011
    Co-Authors: M Gounelle
    Abstract:

    Short-Lived Radionuclides (SLRs) are radioactive elements (T 1/2 ≺ 200 Myr) which were present in the nascent solar system and are now extinct. While the initial abundance of SLRs with the longest half-lives (T 1/2 ≻ 3 Myr) is compatible with the expectations of Galactic evolution models, others have a last-minute origin. 7 Be, 10 Be, 36 Cl, and 41 Ca probably originated within the protoplanetary disk from the irradiation of gas and dust by energetic particles accelerated by the protoSun. 26 Al and 60 Fe were probably synthesized by massive stars and added to interstellar gas which will eventually make up the bulk of our solar system. Identifying the detailed mechanisms of 26 Al and 60 Fe production and mixing will shed a light on the relationship between the Sun formation history and massive stars.

  • the origin of short Lived Radionuclides and the astrophysical environment of solar system formation
    The Astrophysical Journal, 2008
    Co-Authors: M Gounelle, Anders Meibom
    Abstract:

    Based on early solar system abundances of short-Lived Radionuclides (SRs), such as Al-26 (T-1/2 = 0.74 Myr) and Fe-60 (T-1/2 1.5 Myr), it is often asserted that the Sun was born in a large stellar cluster, where a massive star contaminated the protoplanetary disk with freshly nucleosynthesized isotopes from its supernova (SN) explosion. To account for the inferred initial solar system abundances of short-Lived Radionuclides, this supernova had to be close (similar to 0.3 pc) to the young (similar to 1 Myr) protoplanetary disk. Here we show that massive star evolution timescales are too long, compared to typical timescales of star formation in embedded clusters, for them to explode as supernovae within the lifetimes of nearby disks. This is especially true in an Orion Nebular Cluster ( ONC) type of setting, where the most massive star will explode as a supernova similar to 5 Myr after the onset of star formation, when nearby disks will have already suffered substantial photoevaporation and/or formed large planetesimals. We quantify the probability for any protoplanetary disk to receive SRs from a nearby supernova at the level observed in the early solar system. Key constraints on our estimate are: ( 1) SRs have to be injected into a newly formed (<= 1 Myr) disk, ( 2) the disk has to survive UV photoevaporation, and ( 3) the protoplanetary disk must be situated in an enrichment zone permitting SR injection at the solar system level without disk disruption. The probability of protoplanetary disk contamination by a supernova ejecta is, in the most favorable case, 3 x 10(-3). We propose instead that Fe-60 (and possibly Al-26) was inherited from the interstellar medium.

  • irradiation in the early solar system and the origin of short Lived Radionuclides
    Comptes Rendus Geoscience, 2007
    Co-Authors: M Gounelle, Marc Chaussidon, Thierry Montmerle
    Abstract:

    The origin of short-Lived (T ∼ 1 Myr) Radionuclides (SRs) in the early solar system is a matter of debate. Some short-Lived Radionuclides had abundances in the solar protoplanetary disk in excess compared to the expected galactic background ( 7 Be, 10 Be, 26 Al, 36 Cl, 41 Ca and possibly 53 Mn and 60 Fe). These SRs thus either originated from a supernova contamination, or were produced by in situ irradiation of solar system dust or gas, or by Galactic Cosmic Ray (GCR) trapping in the molecular cloud core progenitor of our solar system (for 10 Be only). GCR trapping in the molecular cloud core seems to fail to reproduce the initial abundance of 10 Be, because trapping timescales exceed by one order of magnitude the observed core lifetimes. On the other hand, irradiation models can synthesize large quantities of 10 Be and other SRs ( 7 Be, 36 Cl, 26 Al, 41 Ca and 53 Mn). In addition, X-ray observations of young, solar-like stars provide direct evidence for protoplanetary disk irradiation in a different energy window. The initial abundance of 60 Fe is poorly known, and its presence in the early solar system might be accounted for galactic abundance rather than by a nearby supernova.