Search for beta-delayed proton emission from $$^{11}$$Be

The European Physical Journal A - A deterministic treatment of sequential neutron emission, based on recursive equations of the residual temperatures, was applied to numerous fission cases (i.e. 49...     

Accuracy of 9Be-data and its influence on 10Be cosmogenic nuclide data

A ⁹Be-solution has been chemically prepared from phenakite (Be₂SiO₄) mineral grains as commercial ⁹Be-solutions are too high in long-lived ¹⁰Be. The solution is intended to be used as a carrier for radiochemical separation of ¹⁰Be to be measured by accelerator mass spectrometry (AMS). Thus, accurate data of the ⁹Be-concentration of this solution is essential to guarantee for high-accuracy ¹⁰Be data in the future. After devastating preliminary results (~8 % standard deviation), eight laboratories finally produced twelve individual results by four different analytical methods. A certain lab and method bias might be identified by sophisticated statistical evaluation. Some laboratories also (grossly) underestimate their uncertainties. Thus, the simple weighted mean of this round-robin exercise needed to be corrected by introducing additional allowances (Paule-Mandel-approach). The final result has been calculated to (2,246 ± 11) μg ⁹Be/(g solution) with a reasonably low weighted standard deviation of 0.49 %. The maximum deviation of a single lab value from the weighted mean is 2.4 % when removing one Grubbs outlier (11 % off from the mean) from the data set. As ¹⁰Be-data, which is usually calculated from measured ¹⁰Be/⁹Be by AMS and stable ⁹Be, cannot be more accurate than the determined ⁹Be-concentration, it seems highly advisable to establish or improve quality assurance by having self-made carrier-solutions analysed at more than a single lab and regularly taking part in round-robin exercises.     

Determination of nitrogen in boron carbide by instrumental photon activation analysis

Boron carbide is widely used as industrial material, because of its extreme hardness, and as a neutron absorber. As part of a round-robin exercise leading to certification of a new reference material (ERM-ED102) which was demanded by the industry we analysed nitrogen in boron carbide by inert gas fusion analysis (GFA) and instrumental photon activation analysis (IPAA) using the ¹⁴N(γ,n)¹³N nuclear reaction. The latter approach is the only non-destructive method among all the methods applied. By using photons with energy below the threshold of the ¹²C(γ,n)¹¹C reaction, we hindered activation of matrix and other impurities. A recently installed beam with a very low lateral activating flux gradient enabled us to homogeneously activate sample masses of approximately 1 g. Taking extra precautions, i.e. self-absorption correction and deconvolution of the complex decay curves, we calculated a nitrogen concentration of 2260 ± 100 μg g⁻¹, which is in good agreement with our GFA value of 2303 ± 64 μg g⁻¹. The values are the second and third highest of a rather atypical (non-S-shape) distribution of data of 14 round-robin participants. It is of utmost importance for the certification process that our IPAA value is the only one not produced by inert gas fusion analysis and, therefore, the only one which is not affected by a possible incomplete release of nitrogen from high-melting boron carbide. Figure Twin-Detector system for analyzing spatially extended samples     

Spatially resolved synchrotron radiation induced X-ray fluorescence analyses of rare Rembrandt silverpoint drawings

New analyses of a series of very rare silverpoint drawings that were executed by Rembrandt Harmensz. van Rijn (1606–1669) which are kept today in the Kupferstichkabinett (Museum of Prints and Drawings) of the State Museums of Berlin are reported here. Analysis of these drawings requires particular attention because the study has to be fully non-destructive and extremely sensitive. The metal alloy on the paper does not exceed some hundreds of μg/cm². Therefore, synchrotron radiation induced X-ray fluorescence (SR-XRF) is – together with external micro-proton-induced X-ray emission – the only well-suited method for the analyses of metalpoint drawings. In some primary work, about 25 German and Flemish metalpoint drawings were investigated using spatially resolved SR-XRF analysis at the BAMline at BESSY. This study enlarges the existing French–German database of metalpoint drawings dating from the 15th and 16th centuries, as these Rembrandt drawings originate from the 17th century where this graphical technique was even rarer and already obsolete. It also illustrates how SR-XRF analysis can reinforce art historical assumptions on the dating of drawings and their connection. PACS 89.90.+n; 81.70.Jb; 81.05.Bx     

Evaluation of a sensitive,reasonable, and fast detection method for 55Fe in steel

Journal of Radioanalytical and Nuclear Chemistry - A pilot study to quantify 55Fe in steel from a reactor vessel of a nuclear power plant by accelerator mass spectrometry (AMS) without any chemical...     

Determination of 41Ca with LSC and AMS: method development, modifications and applications

Despite the emission of only low energy Auger electrons (ca. 3.6 keV) and the difficulty of obtaining a certified standard, Liquid scintillation counting (LSC) determinations are still reasonable options for a radioanalytical laboratory involved in nuclear installation decommission. Besides, accelerator mass spectrometry (AMS), being the most sensitive analytical technique not only for ⁴¹Ca, is gaining increasingly broader accessibility and applicability. Herein, we present a radiochemical separation procedure developed for ⁴¹Ca determination with LSC and AMS in varying materials (i.e. water, concrete, sediment, soil, and biota). The radioanalytical isolation consists of anion exchange and extraction chromatography as well as carbonate precipitation and recrystallization from organic solvents. Thereby, interfering radionuclides as ⁵⁵Fe, ⁶⁰Co, ¹⁵²Eu, U or actinides are removed with decontamination factors of 10²–10⁴. Quench curves for determining the measurement efficiency is generated with a ⁴¹Ca solution gained from the ⁴¹Ca/⁴⁰Ca certified reference material ERM-AE701. In routine application the procedure is characterized by chemical yields of 67–86 %, measurement efficiencies of 1–10 % and detection limits of 0.05 Bq g^?1 and 0.3 Bq L^?1. Aliquots of the digestion solutions of LSC can be easily converted into CaF₂–AMS targets by successive oxsalate and fluoride precipitation. Pros and cons for both measurement techniques are addressed based on ⁴¹Ca results from LSC and AMS for the same material.     

Volcanic glass under fire – a comparison of three complementary analytical methods

The two obsidian sources from the island of Melos (Greece), Agia Nychia and Demenegakion, are chemically characterized by three complementary analytical techniques. Ion beam analysis (IBA) comprising particle induced X‐ray emission and particle induced gamma‐ray emission, neutron activation analysis (NAA) and laser ablation inductively coupled plasma mass spectrometry (LA‐ICP‐MS) is applied to the same set of geological obsidian samples. The combination of methods allows a more complete characterization of obsidian sources and reveals a highly specific chemical composition, the so‐called chemical fingerprint. This multi‐methodical approach checks also the self‐consistency of the analytical results and shows not only the most reliable and characteristic key elements Co and Sc but also Fe, Ca and Ti of Melos obsidian deposits. NAA contributes the largest number of reliable elements to the most unambiguous chemical fingerprint comprising in total of 41 elements. Therefore, NAA is the most suitable analytical method for a clear identification of Melos obsidian deposits. Moreover, the accuracy of methods is demonstrated by the excellent correspondences (calculated correlation coefficient R² = 1.00 for IBA and NAA, R² = 0.99 for LA‐ICP‐MS) between determined analytical results obained by IBA, NAA and LA‐ICP‐MS and certified values of the reference glass BAM‐S005B. Copyright © 2013 John Wiley & Sons, Ltd.