Resonance capture cross section of 207Pb

The radiative neutron capture cross section of 207Pb has been measured at the CERN neutron time of flight installation n_TOF using the pulse height weighting technique in the resolved energy region. The measurement has been performed with an optimized setup of two C6D6 scintillation detectors, which allowed us to reduce scattered neutron backgrounds down to a negligible level. Resonance parameters and radiative kernels have been determined for 16 resonances by means of an R-matrix analysis in the neutron energy range from 3 keV to 320 keV. Good agreement with previous measurements was found at low neutron energies, whereas substantial discrepancies appear beyond 45 keV. With the present results, we obtain an s-process contribution of 77(8)% to the solar abundance of 207Pb. This corresponds to an r-process component of 23(8)%, which is important for deriving the U/Th ages of metal poor halo stars.Comment: 7 pages, 3 figures, to be published in Phys. Rev.

Towards the high-accuracy determination of the 238U fission cross section at the threshold region at CERN - N-TOF

The 238U fission cross section is an international standard beyond 2 MeV where the fission plateau starts. However, due to its importance in fission reactors, this cross-section should be very accurately known also in the threshold region below 2 MeV. The 238U fission cross section has been measured relative to the 235U fission cross section at CERN - n-TOF with different detection systems. These datasets have been collected and suitably combined to increase the counting statistics in the threshold region from about 300 keV up to 3 MeV. The results are compared with other experimental data, evaluated libraries, and the IAEA standards

High accuracy 235U(n,f) data in the resonance energy region

This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. C. Paradela, et al, ‘High accuracy 235U(n,f) data in the resonance energy region’, EPJ Web of Conferences, Vol. 111, 2016, WONDER-2015 – 4TH International Workshop on Nuclear Data Evaluation for Reactor applications, 5 – 8 October 2015, Aix-en-Provence, France. Article available at https://www.epj-conferences.org/articles/epjconf/pdf/2016/06/epjconf_wonder2016_02003.pdf © Owned by the authors, published by EDP Sciences, 2016.The 235U neutron-induced cross section is widely used as reference cross section for measuring other fission cross sections, but in the resonance region it is not considered as an IAEA standard because of the scarce experimental data covering the full region. In this work, we deal with a new analysis of the experimental data obtained with a detection setup based on parallel plate ionization chambers (PPACs) at the CERN n-TOF facility in the range from 1 eV to 10 keV. The relative cross section has been normalised to the IAEA value in the region between 7.8 and 11 eV, which is claimed as well-known. Comparison with the ENDF/B-VII evaluation and the IAEA reference file from 100 eV to 10 keV are provided

Data partitioning enables the use of standard SOAP Web Services in genome-scale workflows

Biological databases and computational biology tools are provided by research groups around the world, and made accessible on the Web. Combining these resources is a com- mon practice in bioinformatics, but integration of heterogeneous and often distributed tools and datasets can be challenging. To date, this challenge has been commonly addressed in a pragmatic way, by tedious and error-prone scripting. Recently however a more reliable technique has been identified and proposed as the platform that would tie together bioinfor- matics resources, namely Web Services. In the last decade the Web Services have spread wide in bioinformatics, and earned the title of recommended technology. However, in the era of high-throughput experimentation, a major concern regarding Web Services is their ability to handle large-scale data traffic. We propose a stream-like communication pattern for standard SOAP Web Services, that enables efficient flow of large data traffic between a workflow orchestrator and Web Services. We evaluated the data-partitioning strategy by comparing it with typical communication patterns on an example pipeline for genomic sequence annotation. The results show that data-partitioning lowers resource demands of services and increases their throughput, which in consequence allows to execute in-silico experiments on genome-scale, using standard SOAP Web Services and workflows. As a proof-of-principle we annotated an RNA-seq dataset using a plain BPEL workflow engine

Nuclear astrophysics at n-TOF facility, CERN

The innovative feature of the n-TOF facility at CERN, in the two experimental areas, (20 m and 200 m flight paths), allow for an accurate determination of the neutron capture cross section for radioactive samples or for isotopes with small neutron capture cross section, of interest for Nuclear Astrophysics. This contribution presents an overview on the astrophysical program carried on at the n-TOF facility, the main results and their implications