He stripping for AMS of 236U and other actinides using a 3 MV tandem accelerator

Winkler, Stephan; Steier, Peter; Buchriegler, Josef; Lachner, Johannes; Pitters, Johanna; Priller, Alfred; Golser, Robin

doi:10.1016/j.nimb.2015.04.029

Cited by 28 publications

(19 citation statements)

References 25 publications

(30 reference statements)

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“…The remaining ions are identified in the final detection system, a Bragg type ionization chamber 62 . With this setup an overall detection efficiency of 5Á10 À4 and a detection limit for 236 U/U below 10 À11 was achieved 63 . The detection efficiencies for 233 U and 236 U can be assumed to be comparable due to the similar mass of the two isotopes.…”

Section: Methodsmentioning

confidence: 96%

233U/236U signature allows to distinguish environmental emissions of civil nuclear industry from weapons fallout

et al. 2020

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Isotopic ratios of radioactive releases into the environment are useful signatures for contamination source assessment. Uranium is known to behave conservatively in sea water so that a ratio of uranium trace isotopes may serve as a superior oceanographic tracer. Here we present data on the atomic 233 U/ 236 U ratio analyzed in representative environmental samples finding ratios of (0.1-3.7)Á10 À2 . The ratios detected in compartments of the environment affected by releases of nuclear power production or by weapons fallout differ by one order of magnitude. Significant amounts of 233 U were only released in nuclear weapons fallout, either produced by fast neutron reactions or directly by 233 U-fueled devices. This makes the 233 U/ 236 U ratio a promising new fingerprint for radioactive emissions. Our findings indicate a higher release of 233 U by nuclear weapons tests before the maximum of global fallout in 1963, setting constraints on the design of the nuclear weapons employed.

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Section: Methodsmentioning

confidence: 96%

233U/236U signature allows to distinguish environmental emissions of civil nuclear industry from weapons fallout

et al. 2020

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“…The relatively high stripper gas pressure causes losses of a significant fraction of U 3+ ions to angular scattering and change exchange outside of the stripper assembly. This gives an effective stripping yield of around 21% for the charge state 3+ 50 , which is selected by the subsequent 90° analysing magnet. The combination of the analysing magnet with a Wien filter, an electrostatic analyzer, and a second 90° magnet, efficiently suppresses isotopic background on the high-energy side.…”

Section: Methodsmentioning

confidence: 99%

An unknown source of reactor radionuclides in the Baltic Sea revealed by multi-isotope fingerprints

et al. 2021

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We present an application of multi-isotopic fingerprints (i.e., 236U/238U, 233U/236U, 236U/129I and 129I/127I) for the discovery of previously unrecognized sources of anthropogenic radioactivity. Our data indicate a source of reactor 236U in the Baltic Sea in addition to inputs from the two European reprocessing plants and global fallout. This additional reactor 236U may come from unreported discharges from Swedish nuclear research facilities as supported by high 236U levels in sediment nearby Studsvik, or from accidental leakages of spent nuclear fuel disposed on the Baltic seafloor, either reported or unreported. Such leakages would indicate problems with the radiological safety of seafloor disposal, and may be accompanied by releases of other radionuclides. The results demonstrate the high sensitivity of multi-isotopic tracer systems, especially the 233U/236U signature, to distinguish environmental emissions of unrevealed radioactive releases for nuclear safeguards, emergency preparedness and environmental tracer studies.

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“…[], and Winkler et al . []. All AMS measurements of the 236 U/ 238 U isotopic ratio were performed at the Vienna Environmental Research Accelerator (VERA) facility at the University of Vienna.…”

Section: Methodsmentioning

confidence: 99%

“…The use of He and the 31 charge state provides higher detection efficiency then the previously used method employing Ar and 51 as described in Sakaguchi et al [2012]; the earlier method was, however still used for the sea water samples described in this work. Full details of AMS measurements have been described by Steier et al [2010], Sakaguchi et al [2012], and Winkler et al [2015]. All AMS measurements of the 236 U/ 238 U isotopic ratio were performed at the Vienna Environmental Research Accelerator (VERA) facility at the University of Vienna.…”

Section: Measurement Of U Isotopesmentioning

confidence: 99%

Temporal and vertical distributions of anthropogenic ²³⁶U in the Japan Sea using a coral core and seawater samples

et al. 2016

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The input history of 236U to the surface water of the Japan Sea was reconstructed through measurement of the 236U/238U atom ratio in annual bands of a coral skeleton which was collected at Iki Island in the Tsushima Strait, the main entrance to the Japan Sea. The 236U/238U atom ratios and concentrations of U isotopes were measured for the period 1935–2010 using AMS and ICP‐MS. The 236U/238U atom ratios revealed three prominent peaks: 4.51 × 10−9 in 1955, 6.15 × 10−9 in 1959 and 4.14 × 10−9 in 1963; thereafter the isotope ratios gradually decreased over the next several decades, attaining a value of ca.1.3 × 10−9 for the present day. A simplified depth profile model for 236U in the Japan Sea, using the reconstructed 236U value for the surface water together with observed depth profiles for 236U in the water column in 2010, yielded diffusion coefficients of 3.4–5.6 cm2/s for 6 sampling points. The diffusion coefficient values obtained for the northern stations were relatively large, and fitting uncertainty was also larger for stations in the northern region. It may be presumed that the distribution of 236U in the water columns have been influenced not only by diffusion but also by subduction of the surface water in the Japan Sea.

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He stripping for AMS of 236U and other actinides using a 3 MV tandem accelerator

Cited by 28 publications

References 25 publications

233U/236U signature allows to distinguish environmental emissions of civil nuclear industry from weapons fallout

233U/236U signature allows to distinguish environmental emissions of civil nuclear industry from weapons fallout

An unknown source of reactor radionuclides in the Baltic Sea revealed by multi-isotope fingerprints

Temporal and vertical distributions of anthropogenic ²³⁶U in the Japan Sea using a coral core and seawater samples

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He stripping for AMS of 236U and other actinides using a 3 MV tandem accelerator

Cited by 28 publications

References 25 publications

233U/236U signature allows to distinguish environmental emissions of civil nuclear industry from weapons fallout

233U/236U signature allows to distinguish environmental emissions of civil nuclear industry from weapons fallout

An unknown source of reactor radionuclides in the Baltic Sea revealed by multi-isotope fingerprints

Temporal and vertical distributions of anthropogenic 236U in the Japan Sea using a coral core and seawater samples

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Product

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Temporal and vertical distributions of anthropogenic ²³⁶U in the Japan Sea using a coral core and seawater samples