Dissemination and visualisation of reference decay data from Decay Data Evaluation Project (DDEP)

Conference of 2016 International Conference on Nuclear Data for Science and Technology, ND 2016 ; Conference Date: 11 September 2016 Through 16 September 2016; Conference Code:130583International audienceAs a primary laboratory in the field of ionising radiation metrology, the Laboratoire National Henri Becquerel (LNE-LNHB), CEA Saclay, is involved in measurements, evaluations and dissemination of radioactive decay data. Data measurements undertaken by various laboratories are evaluated by an international commission of experts (Decay Data Evaluation Project) coordinated by LNHB staff in order to establish a set of recommended decay scheme data. New nuclide evaluations are regularly added to our website, the Nucléide database, published in the BIPM-5 Monographie series and uploaded to our web application Laraweb, a dedicated tool for alpha and gamma spectrometry. The Mini Table of Radionuclides is produced from time-to-time with data extracted from our database. Various publications are described, along with new search criteria and decay scheme visualisation in Laraweb

Nuclide++: A C++ module to include DDEP recommended radioactive decay Data in Geant4

International audienceThis article describes the Nuclide$++$ module developed at LNE-LNHB to simulate the decay schemes related to single or multiple radionuclides, by randomly selecting decay pathways. Written in C$++$, with respect of the Geant4 coding style, this module can be used transparently in Geant4-based simulation applications as an alternative to the existing Radioactive Decay Module (RDM). Nuclide$++$ takes advantage of the DDEP recommended data, accurate $\beta$-emitting spectra calculation and detailed description of the atomic rearrangement. This module can be useful in many applications, especially those involving radioactive sources. The reliability of the module was verified through comparisons with a while chosen radionuclides

Atomic and nuclear decay data evaluations at the French national metrology laboratory for ionising radiation

International audienceAs part of the activity related to atomic and nuclear decay data evaluations, the French national metrology laboratory for ionising radiation, the Laboratoire National Henri Becquerel (LNE-LNHB), coordinates the Decay Data Evaluation Project (DDEP). The DDEP is an international collaboration providing easy-to-use and reliable decay data recommendations. It was originally founded in 1994 between two National Metrology Institutes (NMIs) for ionising radiation: the LNE-LNHB, France, and the Physikalisch-Technische Bundesanstalt (PTB) in Germany. The collaboration was later strengthened through the addition of laboratories from the US, China, Romania, Russia, Spain and the UK. Beyond the initial scope of ionising radiation metrology, the DDEP recommendations are used for a wide variety of topics, from fundamental physics to nuclear medicine applications. Most notably, almost all 220 DDEP evaluations are included in the latest version of the radioactive decay data library from the Joint Evaluated Fission and Fusion (JEFF) file project of the OECD Nuclear Energy Agency.This communication aims to present an overview of the evaluation project. The guidelines of the collaboration as well as the evaluation pipeline will be presented. The various dissemination media used by the collaboration will be detailed and the recent update of the website will be highlighted. The future improvements of the database will be discussed

Calculation of beta spectra for allowed and unique forbidden transitions

International audienceIn ionizing radiation metrology, the energy spectra of beta decays are often needed, especially when measurements are carried out using Liquid Scintillation Counting. The uncertainties on activity measurements can be reduced with a precise knowledge of the shapes of the beta spectra. The few studies which have been conducted on this subject since the 1970s were mainly focused on allowed and first non-unique forbidden transitions. But it is also necessary to have a good knowledge of spectra for unique and non-unique forbidden transitions of higher orders. Our goal is to develop a computer program for calculating beta spectra, validated by experiments, including evaluated uncertainties on the shapes. The exhaustive evaluation of form factors measured so far shows that there are not enough good data to validate those complex calculations. All these considerations highlight the need for a consistent experimental program in which all the distortion phenomena of beta spectra should be analysed and quantified very carefully. This paper describes the present features of the computer program we have developed, BetaShape, and specifies the future work which should be undertaken to improve it

Experimental and Theoretical Study of the Chemical Network of the Hydrogenation of NO on Interstellar Dust Grains

Nitrogen monoxide (NO) is observed in the gas phase of molecular clouds. It may accrete on dust grains, and there its hydrogenation should lead to hydroxylamine (NH2OH), the same way that CO is transformed into methanol (CH3OH) on the surface of dust grains. NO hydrogenation has been said barrier-less, whereas CO hydrogenation proceed through quantum tunneling, and is thus slower. However, CH3OH is widely observed and is considered as a proxy of complex organic molecules while hydroxylamine remains undetected. We aim at studying, analyzing, and understanding the chemical network of NO hydrogenation on cold surfaces. Experiments are carried out using a new ultrahigh vacuum (UHV) setup named VENUS. NO molecules and H atoms are codeposited on a golden mirror at different temperatures. Infrared spectroscopy as well as temperature-programmed desorption (TPD) are used to follow the NO reactivity, with both H and D, and in presence or absence of water substrate. Quantum calculations on water ice cluster models are computed separately. During the hydrogenation of NO, 10 reactions proceed concurrently. They are identified and constrained by changing physical conditions in experiments or in calculations. Among them, we demonstrate that the HNO + H addition reaction has a barrier which is probably crossed via quantum tunneling at 10 K. Moreover, abstraction reactions are occurring although they are limited by H and O bonding with their environment. Chemical desorption should occur especially in the absence of water which enhances the total production of hydroxylamine. The chemical network of the hydrogenation of NO has been reinvestigated. Each of the 10 reactions are sorted by efficiency. We exclude the possibility of a chemical loop between NO and HNO, especially in the presence of water. Therefore, hydroxylamine remains the main product of the hydrogenation of NO on grains, and the question of its nondetection in ices or in the gas phase, specifically in shocked regions where ice mantles should be sputtered, is still open

Experimental and Theoretical Study of the Chemical Network of the Hydrogenation of NO on Interstellar Dust Grains

International audienceNitrogen Monoxide (NO) is observed in the gas phase of molecular clouds. It may accrete on dust grains and there its hydrogenation should lead to hydroxylamine (NH 2 OH), the same way that CO is transformed in methanol (CH 3 OH) on the surface dust grains. NO hydrogenation has been said barrier-less, whereas CO hydrogenation proceed through quantum tunneling, and is thus slower. However, CH 3 OH is widely observed and is considered as a proxy of complex organic molecules while hydroxy-lamine remains undetected. We aim at studying, analyzing, and understanding the 1 chemical network of NO hydrogenation on cold surfaces. Experiments are carried out using a new Ultra-Hight Vacuum (UHV) setup named VENUS. NO molecules and H atoms are co-deposited on a golden mirror at different temperatures. Infrared spectroscopy as well as Temperature Programmed Desorption (TPD) are used to follow the NO reactivity, with both H and D, and in presence or absence of water substrate. Quantum calculations on water ice cluster models are computed separately. During the hydrogenation of NO, 10 reactions proceed concurrently. They are identified and constrained by changing physical conditions in experiments or in calculations. Among them, we demonstrate that the HNO+H addition reaction has a barrier which is probably crossed via quantum tunneling at 10 K. Moreover, abstraction reactions are occurring although they are limited by H and O bonding with their environment. Chemical desorption should occur especially in absence of water which enhances the total production of hydroxylamine. The chemical network of the hydrogenation of NO has been re-investigated. Each of the 10 reactions are sorted by efficiency. We exclude the possibility of a chemical loop between NO and HNO, especially in presence of water. Therefore hydroxylamine remains the main product of the hydrogenation of NO on grains and the question of its non-detection in ices or in the gas phase, specifically in shocked regions where ice mantles should be sputtered, is still open

Monographie BIPM-5 Table of Radionuclides (Vol. 7 -A = 14 to 245)

International audienceThe purpose of this monograph, number 5 of the series, is to present the recommended values of nuclear and decay data for a wide range of radionuclides. Activity measurements for more than sixty-three of these radionuclides have already been the subject of comparisons under the auspices of the Section II (dedicated to the measurement of radionuclides) of the CCRI. The material for this monograph is now covered in seven volumes. The first two volumes contain 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 a set of sixty-eight radionuclides, Volume 1 for those radionuclides with mass number up to and including 150 and Volume 2 for those radionuclides with mass number over 150. Volume 3 contains the equivalent data for twenty-six additional radionuclides as listed and re-evaluation for 125Sb and 153Sm. Volume 4 contains the data for a further thirty-one radionuclides with re-evaluation for 226Ra. Volume 5 includes seventeen new radionuclide evaluations and eight re-evaluations of previous data as identified in the contents pages. Volume 6 contains twenty-one new radionuclide evaluations and four re-evaluations for 64Cu, 236Np, 237Np and 239U. Volume 7 contains twenty-four new radionuclide evaluations and five re-evaluations for 67Ga, 208Tl, 228 Th, 242Cm and 244Cm. The data have been collated and evaluated by an international working group (Decay Data Evaluation Project) led by the Laboratoire National de métrologie et d'Essais - Laboratoire national Henri Becquerel (LNE-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 kept up to date on the LNE-LNHB website at http://www.nucleide.org/DDEP_WG/DDEPdata.ht

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