| 1. |
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| 2. |
- Podolyak, Z., et al.
(författare)
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gamma-ray spectroscopy with a He-8 beam
- 2003
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 511:3, s. 354-359
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Tidskriftsartikel (refereegranskat)abstract
- The He-8 + Pb-208 reaction was studied in the first experiment with the EXOGAM germanium detector array using beam delivered by the SPIRAL facility. gamma-rays from direct and fusion-evaporation reactions were observed with high resolution. gamma-gamma coincidence data were obtained at a beam intensity level of 105 8He particles per second. Specially designed absorbers and beam detectors could further reduce the background radiation by orders of magnitude.
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| 3. |
- Mach, Henryk, et al.
(författare)
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Ultrafast-timing lifetime measurements in Ru-94 and Pd-96 : Breakdown of the seniority scheme in N=50 isotones
- 2017
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Ingår i: PHYSICAL REVIEW C. - : American Physical Society. - 2469-9985. ; 95:1
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Tidskriftsartikel (refereegranskat)abstract
- The advanced time-delayed gamma gamma(t) method has been applied to determine half-lives of low-lying states in the N = 50 isotones Ru-94 and Pd-96. The inferred experimental E2 strengths for the 4(+) -> 2(+) transitions in the two nuclei show a dramatic deviation with respect to the shell model predictions in the (f(5/2), p, g(9/2)) proton hole space in Sn-100. The anomalous behavior can be ascribed to a breakdown of the seniority quantum number in the pi g(9/2)(n) configuration due to particle-hole excitations across the N = Z = 50 shell as confirmed by large-scale shell model calculations.
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| 4. |
- Voitsekhovitch, I., et al.
(författare)
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Recent EUROfusion Achievements in Support of Computationally Demanding Multiscale Fusion Physics Simulations and Integrated Modeling
- 2018
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Ingår i: Fusion Science and Technology. - : Informa UK Limited. - 1536-1055 .- 1943-7641. ; 74:3, s. 186-197
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Tidskriftsartikel (refereegranskat)abstract
- © 2018, © 2018 The Authors. Published with license by Taylor & Francis Group, LLC. Integrated modeling (IM) of present experiments and future tokamak reactors requires the provision of computational resources and numerical tools capable of simulating multiscale spatial phenomena as well as fast transient events and relatively slow plasma evolution within a reasonably short computational time. Recent progress in the implementation of the new computational resources for fusion applications in Europe based on modern supercomputer technologies (supercomputer MARCONI-FUSION), in the optimization and speedup of the EU fusion-related first-principle codes, and in the development of a basis for physics codes/modules integration into a centrally maintained suite of IM tools achieved within the EUROfusion Consortium is presented. Physics phenomena that can now be reasonably modelled in various areas (core turbulence and magnetic reconnection, edge and scrape-off layer physics, radio-frequency heating and current drive, magnetohydrodynamic model, reflectometry simulations) following successful code optimizations and parallelization are briefly described. Development activities in support to IM are summarized. They include support to (1) the local deployment of the IM infrastructure and access to experimental data at various host sites, (2) the management of releases for sophisticated IM workflows involving a large number of components, and (3) the performance optimization of complex IM workflows.
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| 5. |
- Olaizola, B., et al.
(författare)
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High-sensitivity study of levels in Al-30 following beta decay of Mg-30
- 2016
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Ingår i: PHYSICAL REVIEW C. - 2469-9985 .- 2469-9993. ; 94:5
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Tidskriftsartikel (refereegranskat)abstract
- gamma-ray and fast-timing spectroscopy were used to study levels in Al-30 populated following the beta(-) decay of Mg-30. Five new transitions and three new levels were located in Al-30. A search was made to identify the third 1(+) state expected at an excitation energy of similar to 2.5 MeV. Two new levels were found, at 3163.9 and 3362.5 keV, that are firm candidates for this state. Using the advanced time-delayed (ATD) beta gamma gamma (t) method we have measured the lifetime of the 243.8-keV state to be T-1/2 = 15(4) ps, which implies that the 243.8-keV transition is mainly of M1 character. Its fast B(M1; 2(+) -> 3(+)) value of 0.10(3) W.u. is in very good agreement with the USD shell-model prediction of 0.090 W.u. The 1801.5-keV level is the only level observed in this study that could be a candidate for the second excited 2(+) state.
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| 6. |
- Strand, Pär, 1968, et al.
(författare)
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A European infrastructure for fusion simulations
- 2010
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Ingår i: Proceedings of the 18th Euromicro Conference on Parallel, Distributed and Network-Based Processing, PDP 2010. - 9780769539393 ; , s. 460-467
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The Integrated Tokamak Modelling Task Force (ITM-TF) is developing an infrastructure where the validation needs, as being formulated in terms of multi-device data access and detailed physics comparisons aiming for inclusion of synthetic diagnostics in the simulation chain, are key components. A device independent approach to data transport and a standardized approach to data management (data structures, naming, and access) is being developed in order to allow cross validation between different fusion devices using a single toolset. The effort is focused on ITER plasmas and ITER scenario development on current fusion device. The modeling tools are, however, aimed for general use and can be promoted in other areas of modelling as well. Extensive work has already gone into the development of standardized descriptions of the data (Consistent Physical Objects) providing initial steps towards a complete fusion modelling ontology. The longer term aim is a complete simulation platform which is expected to last and be extended in different ways for the coming 30 years. The technical underpinning is therefore of vital importance. In particular, the platform needs to be extensible and open-ended to be able to take full advantage of not only today's most advanced technologies but also be able to marshal future developments. A full level comprehensive prediction of ITER physics rapidly becomes expensive in terms of computing resources and may cover a range of computing paradigms. The simulation framework therefore needs to be able to use both grid and HPC computing facilities. Hence, data access and code coupling technologies are required to be available for a heterogeneous, possibly distributed, environment. The developments in this area are pursued in a separate project - EUFORIA (EU Fusion for ITER Applications). The current status of ITM-TF and EUFORIA is presented and discussed. © 2010 IEEE.
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| 7. |
- Guillerminet, B., et al.
(författare)
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High Performance Computing tools for the Integrated Tokamak Modelling project
- 2010
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Ingår i: Fusion Engineering and Design. - : Elsevier BV. - 0920-3796. ; 85:3-4, s. 388 - 393
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Tidskriftsartikel (refereegranskat)abstract
- Fusion Modelling and Simulation are very challenging and the High Performance Computing issues are addressed here. Toolset for jobs launching and scheduling, data communication and visualization have been developed by the EUFORIA project and used with a plasma edge simulation code.
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| 8. |
- Imbeaux, F., et al.
(författare)
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Design and first applications of the ITER integrated modelling & analysis suite
- 2015
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 55:12
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Tidskriftsartikel (refereegranskat)abstract
- The ITER Integrated Modelling & Analysis Suite (IMAS) will support both plasma operation and research activities on the ITER tokamak experiment. The IMAS will be accessible to all ITER members as a key tool for the scientific exploitation of ITER. The backbone of the IMAS infrastructure is a standardized, machine-generic data model that represents simulated and experimental data with identical structures. The other outcomes of the IMAS design and prototyping phase are a set of tools to access data and design integrated modelling workflows, as well as first plasma simulators workflows and components implemented with various degrees of modularity.
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| 9. |
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| 10. |
- Mach, H., et al.
(författare)
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New structure information on Mg-30, Mg-31 and Mg-32
- 2005
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Ingår i: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-601X .- 1434-6001. ; 25, s. 105-109
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Konferensbidrag (refereegranskat)abstract
- The fast timing beta gamma gamma(t) method was applied to investigate the level lifetimes in Mg-30,Mg-31,Mg-32. Levels in Mg have been populated in beta and beta-delayed neutron emission of Na, at the ISOLDE facility. From the gamma gamma coincidences a number of new states have been identified and new level schemes were constructed for 30 31,32 Mg. The following preliminary half lives have been determined: T-1/2 = 3.9(4) ns for the 1789 keV state in Mg-30, T-1/2 = 133(8) ps and 10.5(8) us for the 221 keV and 461 keV states in Mg-31, respectively, and T1/2 = 16(4) ps for the 885 keV level in 32Mg. The 1789 keV level was established as a candidate for the intruder 0(+) configuration in Mg-30 with a possible strong E0 branch to the ground state.
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| 11. |
- Owsiak, M., et al.
(författare)
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Running simultaneous Kepler sessions for the parallelization of parametric scans and optimization studies applied to complex workflows
- 2016
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Ingår i: Procedia Computer Science. - : Elsevier. - 1877-0509. ; , s. 690-699
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Konferensbidrag (refereegranskat)abstract
- In this paper we present an approach taken to run multiple Kepler sessions at the same time. This kind of execution is one of the requirements for Integrated Tokamak Modelling platform developed by the Nuclear Fusion community within the context of EUROFusion project [2]. The platform is unique and original: it entails the development of a comprehensive and completely generic tokamak simulator including both the physics and the machine, which can be applied for any fusion device. All components are linked inside work ows. This approach allows complex coupling of various algorithms while at the same time provides consistency. Work ows are composed of Kepler and Ptolemy II elements as well as set of the native libraries written in various languages (Fortran, C, C++). In addition to that, there are Python based components that are used for visualization of results as well as for pre/post processing. At the bottom of all these components there is a database layer that may vary between software releases, and require di erent version of access libraries. The community is using shared virtual research environment to prepare and execute work ows. All these constraints make running multiple Kepler sessions really challenging. However, ability to run numerous sessions in parallel is a must - to reduce computation time and to make it possible to run released codes while working with new software at the same time. In this paper we present our approach to solve this issue and examples that show its correctness.
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| 12. |
- Plociennik, M., et al.
(författare)
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Application scenarios using serpens suite for Kepler scientific workflow system
- 2012
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Ingår i: Procedia Computer Science. - : Elsevier BV. - 1877-0509. ; 9, s. 1604-1613
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Konferensbidrag (refereegranskat)abstract
- This paper presents the overview of exploitation scenarios making use of the Serpens suite for the Kepler workflow orchestration system. The proposed framework provides researchers with an easy-to-use, workflow-based environment for scientific computations. It allows execution of various applications coming from different disciplines, in various distributed computational environments using a user-friendly interface. This research has been driven initially by Nuclear Fusion applications' requirements, where the leading idea was to enhance the modeling capabilities for ITER sized plasma research by providing access to High Performance Computing resources. Several usage scenarios are being presented with an example of applications from the field of Nuclear Fusion, Astrophysics and Computational Chemistry.
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| 13. |
- Coster, D., et al.
(författare)
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Towards making fusion data FAIR
- 2021
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Ingår i: Proceedings - IEEE 17th International Conference on eScience, eScience 2021. ; , s. 233-234
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Konferensbidrag (refereegranskat)abstract
- The concept of FAIR data is being increasingly adopted at national and global levels as a way of maximising the impact and transparency of publicly-funded research outcomes and data. In this paper we introduce the FAIR requirements of the Fusion community as well as technological directions proposed by the Fair4Fusion project aiming at increasing the accessibility to fusion data.
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| 14. |
- Frauel, Y., et al.
(författare)
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Easy use of high performance computers for fusion simulations
- 2012
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Ingår i: Fusion Engineering and Design. - : Elsevier BV. - 0920-3796. ; 87:12, s. 2057-2062
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Tidskriftsartikel (refereegranskat)abstract
- Fusion Modelling and Simulation are very challenging and the high performance computing issues are addressed here. Based on the framework developed by the European Integrated Tokamak Modelling project and on the EUFORIA infrastructure, a tool solving nicely these difficulties has been developed for the end users and applied to several fusion simulation cases. The first part recalls the issues with GRID and high performance computing, while the second part presents the solutions and the tool for developing easily a GRID/HPC actor. The last part reports the use of this tool in MHD equilibrium and plasma edge simulations.
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| 15. |
- Ruchowska, E., et al.
(författare)
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Nuclear structure of Th-229
- 2006
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Ingår i: Physical Review C. Nuclear Physics. - : American Physical Society. - 0556-2813 .- 1089-490X. ; 73:4
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Tidskriftsartikel (refereegranskat)abstract
- Lifetimes of excited states in Th-229, populated in the beta decay of Ac-229, have been measured using the advanced time-delayed beta gamma gamma(t) method. Half-lives of 14 states have been determined including 11 of them for the first time. Twenty-seven new gamma lines have been introduced into the beta-decay scheme of Ac-229 based on results of gamma gamma coincidence measurements. Reduced transition probabilities have been determined for more than 70 gamma transitions in Th-229. Average parallel to D-0 parallel to values of 0.029(1), 0.077(3), and 0.024(5) e fm have been deduced for the lowest K-pi=1/2(+/-),3/2(+/-), and 5/2(+/-) parity partner bands, respectively. Excited states in Th-229 and experimental transition rates have been interpreted within the quasiparticle-plus-phonon model. The half-life of the 3.5-eV, 3/2(+) isomeric state is predicted to be about 10 h. Potential energy surfaces on the (beta(2),beta(3)) plane for the lowest single quasiparticle configurations in Th-229 have been calculated using the Strutinsky method.
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| 16. |
- Strand, Pär, 1968, et al.
(författare)
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A FAIR based approach to data sharing in Europe
- 2022
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Ingår i: Plasma Physics and Controlled Fusion. - : IOP Publishing. - 1361-6587 .- 0741-3335. ; 64:10
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Tidskriftsartikel (refereegranskat)abstract
- The European fusion research activities have, over recent decades, generated a vast and varied set of data. The volume and diversity of the data that need to be catalogued and annotated make the task of organising and making the data available within a broader environment very challenging. Nevertheless, there are strong scientific drivers as well as incentives and mandates from national research agencies suggesting that a more coherent approach to data referencing, dissemination and sharing would provide strong benefits to the fusion research community and beyond. Here, we discuss the technical requirements and developments needed to transition the current, and future, range of fusion research data to an open and Findable, Accessible, Interoperable, and Reusable data sharing structure guided by the principle 'as open as possible, as closed as necessary'. Here we propose a set of recommendations and technical implementations needed to form a European data sharing environment for the fusion research programmes. Consistency with the emerging IMAS (ITER Integrated Modelling and Analysis Suite) infrastructure is considered to facilitate future deployments.
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| 17. |
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| 18. |
- Ruchowska, E., et al.
(författare)
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Quenching of the E1 strength in Nd-149
- 2010
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Ingår i: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-6001 .- 1434-601X. ; 45:1, s. 1-10
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Tidskriftsartikel (refereegranskat)abstract
- Lifetime measurements of excited states in Nd-149 have been performed using the advanced time-delayed beta gamma gamma(t) method. Half-lives of 14 excited states in Nd-149 have been determined for the first time or measured with higher precision. Twelve new gamma-lines and 5 new levels have been introduced into the decay scheme of Pr-149 based on results of the gamma gamma coincidence measurements. Reduced transition probabilities have been determined for 40 gamma-transitions in Nd-149. Configuration assignments for 6 rotational bands in Nd-149 are proposed. Enhanced E1 transitions indicate that the ground-state band and the band built on the 332.9 keV level constitute a pair of the K-pi = 5/2(+/-) parity doublet bands. Potential energy surfaces on the (beta(2),beta(3))-plane have been calculated for the lowest single quasi-particle configurations in Nd-149 using the Strutinski method and the axially deformed Woods-Saxon potential. The predicted occurrence of the octupole-deformed K = 5/2 configuration is in agreement with experiment. Unexpectedly low vertical bar D-0 vertical bar values obtained for the K-pi = 5/2(+/-) parity doublet bands may result from cancellation between the proton and neutron shell correction contributions to vertical bar D-0 vertical bar.
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| 19. |
- Ruchowska, E., et al.
(författare)
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Search for octupole correlations in Nd-147
- 2015
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 92:3
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Tidskriftsartikel (refereegranskat)abstract
- Properties of excited states in Nd-147 have been studied with the multispectra and gamma gamma coincidencemeasurements. Twenty-four new gamma lines and three new levels have been introduced into the level scheme of Nd-147. Using the advanced time-delayed beta gamma gamma(t) method, we measured lifetimes of eight excited levels in Nd-147, populated via the beta decay of Pr-147. We have determined reduced transition probabilities for 30 gamma transitions. Multidimensional potential energy surface calculations performed for Nd-147 suggest two single-quasiparticle configurations with nonzero octupole deformation, with K = 1/2 and K = 5/2. Our calculations also predict a sizable value of the electric dipole moment vertical bar D-0 vertical bar = 0.26e fm for this nucleus, while experimentally, a lower limit of vertical bar D-0 vertical bar >= 0.02e fm has been evaluated for the supposed K = 1/2 parity doublet. In contrast to the theoretical results, we do not observe the parity doublet bands with K = 5/2. This, and the lack of theoretically expected E1 strength in Nd-147,Nd-149 may signal some poorly understood structural effect in the odd-N lanthanides.
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