Practical IR extinction coefficients for water in commercial glasses determined by nuclear reaction analysis

For a number of commercial glasses with different chemical compositions the water contents were determined by nuclear reaction analysis (NRA) measurements. These results were used to deduce practical extinction coefficients by comparison with the measured IR absorbance values at 2.8 μm. For aluminosilicate and television glasses the practical molar extinction coefficients are given for the first time. Practical extinction coefficients are dependent upon glass composition. With increasing basicity of the glasses studied they decrease from 182 to 24 l/(mol cm)

Distribution and community formation by Calamagrostis phragmitoides HARTMAN (Scandinavian Small-reed, Poaceae) in the German Harz Mountains

Calamagrostis phragmitoides wurde erstmals 1983 im Harz entdeckt. Mittlerweile sind zahlreiche weitere Wuchsorte bekannt, die sich alle in Höhenlagen zwischen 500 und 650m ü.NN befinden. Auf­grund der teilweise schwierigen Abgrenzung von der im Harz allgegenwärtigen und morphologisch sehr variablen Calamagrostis villosa bzw. aufgrund von Verwechslungen mit Calamagrostis canescens blieben die Vorkommen von C. phragmitoides im Harz lange unentdeckt. Mehrheitlich sind die untersuchten Exemplare apomiktisch und fallen in die Variationsbreite der als wichtig erachteten Merkmale. Allerdings treten im Harz auch Individuen auf, deren morphologische Merkmale (incl. Habitus) völlig mit apomiktischem C. phragmitoides übereinstimmen, aber stets aufblühen und aus ihren sich öffnenden Antheren Pollenkörner entlassen. Hier handelt es sich offensicht­lich um Formen der C. phragmitoides, die vorerst als „Calamagrostis phragmitoides pollenbildend“ bezeichnet werden. Ergänzend wurden in den Jahren 1998 und 1999 an zahlreichen Wuchsorten Vegetationsaufnahmen erstellt, die die Soziologie des Purpur-Reitgrases dokumentieren. Neben Vorkommen in lichten Erlen­wäldern und an Bachufern wächst die Art in anthropogen entstandenen, allerdings aktuell nicht mehr genutzten Kleinseggenriedern des Caricion fuscae und Hochstaudenfluren sowie aufgelassenen Feucht­wiesen (Filipendulenion bzw. Calthion palustris). Diese Vergesellschaftung ist für C. phragmitoides zumindest in Mitteleuropa typisch. Bemerkenswert ist die Fähigkeit dieses Glazialrelikts, geeignete Offenlandbiotope in räumlicher Nähe zu „natürlichen Vorkommen“ nach Nutzungsaufgabe zu besie­deln und vielerorts die vorhandene Vegetation zu verdrängen. Das Resultat sind artenarme Calamagro­stis phragmitoides-Dominanzbestände.After a first find in the Harz Mountains in 1983, Calamagrostis phragmitoides has been observed numerous times in other places within a narrow elevation range from 500m to 650m. Due to difficulties in separating this species from the very abundant and polymorphic Calamagrostis villosa and due to confusion with Calamagrostis canescens, this species has long been overlooked in the Harz Mountains. Most specimens investigated are apomyctic and fall well within the variability of the species relative to important characters. Nevertheless indiviuals do occur which are morphologically identical with apomyctic C. phragmitoides but which start to flower and show considerable pollen release. These seem to be forms of C. phragmitoides, which will be preliminarily called "Calamagrostis phragmitoides pollen-releasing“ In 1998 and 1999 vegetation samples were gathered from many C. phragmitoides stands in order to elu­cidate the phytosociology of the species. Stands have been examined in open alder forests, on stream-banks, in formerly used but nowaday abandoned Caricion fuscae sedge communities, in tall herb stands as well as in abandoned Filipendulenion and Calthion meadows. This set of communities seems to be typical for C. phragmitoides, at least in central Europe. Noteworthy is the ability of this glacial relict species to colonize and often take over suitable open habitat near presumed natural occurences after human activity has ceased in those secondary habitats. The result are very species-poor stands domina­ted by C. phragmitoides dominance stands

Table of radionuclides (Vol. 1 - A = 1 to 150)

International audienceThe purpose of this monograph, number 5 of the series, is to present the recommended values of nuclear and decay data for a set of sixty-eight radionuclides. Activity measurements for thirty-two of these radionuclides have already been the subject of comparisons under the auspices of the Section II of the CCRI. The material for this monograph will be covered in two volumes. Volume I contains the primary recommended data relating to half-lives, decay modes, x-rays, gamma-rays, electron emissions, alpha- and beta-particle transitions and emissions, and their uncertainties for radionuclides with mass number up to and including 150. Volume 2 contains the equivalent data for radionuclides with mass number over 150. The data have been collated and evaluated by an international working group (Decay Data Evaluation Project) led by the BNM-LNHB. The evaluators have agreed on the methodologies to be used and the CD-ROM included with this monograph contains the evaluators' comments for each radionuclide in addition to the data tables included in the monograph.The work involved in evaluating nuclear data is on-going and the recommended values are updated on the LNHB website at http://www.nucleide.org/DDEP_WG/DDEPdata.ht

Monographie BIPM-5 Table of Radionuclides (Vol. 2 -A = 151 to 242)

International audienceThe purpose of this monograph, number 5 of the series, is to present the recommended values of nuclear and decay data for a set of sixty-eight radionuclides. Activity measurements for thirty-two of these radionuclides have already been the subject of comparisons under the auspices of the Section II of the CCRI. The material for this monograph will be covered in two volumes. Volume I contains the primary recommended data relating to half-lives, decay modes, x-rays, gamma-rays, electron emissions, alpha- and beta-particle transitions and emissions, and their uncertainties for radionuclides with mass number up to and including 150. Volume 2 contains the equivalent data for radionuclides with mass number over 150. The data have been collated and evaluated by an international working group (Decay Data Evaluation Project) led by the BNM-LNHB. The evaluators have agreed on the methodologies to be used and the CD-ROM included with this monograph contains the evaluators' comments for each radionuclide in addition to the data tables included in the monograph. The work involved in evaluating nuclear data is on-going and the recommended values are updated on the LNHB website at http://www.nucleide.org/DDEP_WG/DDEPdata.ht

Half-life determination and comparison of activity standards of 231Pa

The results of an international comparison of activity measurements of a solution of 231Pa are reported and analysed. Prior to this, no known standardisation of 231Pa by activity measurement had been carried out. The comparison was run in 2017–2018 involving eight laboratories, and returned results with no identifiable inconsistencies between methods or laboratories. The results, including one mass determination, gave a231Pa activity concentration of 41.461(48) kBq g−1 and a231Pa atom concentration of 61.48(23) × 1015 atoms g−1, from which a half-life value of 32 570(130) years was derived.JRC.G.2-Standards for Nuclear Safety, Security and Safeguard

Alpha-Particle Emission Probabilities in the Decay of 240Pu

Sources of enriched 240Pu were prepared by vacuum evaporation on quartz substrates. High-resolution alpha-particle spectrometry of 240Pu was performed with high statistical accuracy using silicon detectors and with low statistical accuracy using a bolometer. The alpha-particle emission probabilities of six transitions were derived from the spectra and compared with literature values. Additionally, some alpha-particle emission probabilities were derived from gamma-ray intensity measurements with a high-purity germanium detector. The alpha-particle emission probabilities of the three main transitions at 5168.1, 5123.6 and 5021.2 keV were derived from seven aggregate spectra analysed with five different fit functions and the results were compatible with evaluated data. Two additional weak peaks at 4863.5 and 4492.0 keV were fitted separately, using the exponential of a polynomial function to represent the underlying tailing of the larger peaks. The peak at 4655 keV could not be detected by alpha-particle spectrometry, while gamma-ray spectrometry confirms that its intensity is much lower than expected from literature.JRC.D.4-Nuclear physic

Results of the EURAMET.RI(II)-S6.I-129 supplementary comparison

International audienceAn international comparison of the long-lived gamma-ray emitter 129I has been recently completed. A total of 5 laboratories measured a solution prepared by Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT). Aliquots of the master solution were standardized in terms of activity per mass unit by participant laboratories using 4 different techniques. The results of the comparison can be used as the basis for establishing the equivalence among the laboratories

Results of the EURAMET.RI(II)- S7.Sm-151 supplementary comparison (EURAMET Project 1292)

An international comparison of the activity standardisation of the relatively long-lived gamma-ray emitter 151Sm has been recently completed. A total of six laboratories measured a solution prepared by CEA/LNHB and CEA/LANIE. Aliquots of the master solution were standardized in terms of activity per mass unit by participant laboratories using 2 different techniques. The results of the comparison can be used as the basis for establishing equivalence among the laboratories. The activity measurements of this comparison are part of the joint research project “Metrology for Radioactive Waste Management” of the European Metrology Research Programme (EMRP). One aim of this project is a new determination of the 151Sm half-life.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard

Results of the EURAMET.RI(II)- S7.Sm-151 supplementary comparison (EURAMET Project 1292)

International audienceAn international comparison of the activity standardisation of the relatively long-lived gamma-ray emitter Sm-151 has been recently completed. A total of six laboratories measured a solution prepared by CEA/LNHB and CEA/LANIE. Aliquots of the master solution were standardized in terms of activity per mass unit by participant laboratories using 2 different techniques. The results of the comparison can be used as the basis for establishing equivalence among the laboratories. The activity measurements of this comparison are part of the joint research project 'Metrology for Radioactive Waste Management' of the European Metrology Research Programme (EMRP). One aim of this project is a new determination of the Sm-151 half-life