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- Gatu Johnson, Maria, 1978-, et al.
(author)
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Neutron emission from beryllium reactions in JET deuterium plasmas with 3He minority
- 2010
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In: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 50:4, s. 045005-
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Journal article (peer-reviewed)abstract
- Recent fast ion studies at JET involve ion cyclotron resonance frequency (ICRF) heating tuned to minority He-3 in cold deuterium plasmas, with beryllium evaporation in the vessel prior to the session. During the experiments, the high-resolution neutron spectrometer TOFOR was used to study the energy spectrum of emitted neutrons. Neutrons of energies up to 10MeV, not consistent with the neutron energy spectrum expected from d(d,n)He-3 reactions, were observed. In this paper, we interpret these neutrons as a first-time observation of a Be-9(He-3, n)C-11 neutron spectrum in a tokamak plasma, a conclusion based on a consistent analysis of experimental data and Monte Carlo simulations. Be-9(a, n)C-12 and Be-9(p, n)B-9 reactions are also simulated for p and a fusion products from d(He-3, a) p reactions; these two-step processes are seen to contribute on a level of about 10% of the single-step process in Be-9(He-3, n) C-11. Contributions to the total neutron yield from the Be-9(3He, n)C-11 reaction are found to be in the range 13 +/- 3 to 57 +/- 5%. We demonstrate how TOFOR can be used to simultaneously (i) probe the deuterium distribution, providing reliable measurements of the bulk deuterium temperature, here in the range 3.2 +/- 0.4 to 6.3 +/- 1.0 keV and (ii) provide an estimate of the beryllium concentration (in the range 0.48 +/- 0.17 to 6.4 +/- 1.7% of n(e) assuming T-3He = 300 keV). The observation of Be-9 related neutrons is relevant in view of the upcoming installation of a beryllium-coated ITER-like wall on JET and for ITER itself. An important implication is possible neutron-induced activation of the ITER vessel during the low-activation phase with ICRF heating tuned to minority He-3 in hydrogen plasmas.
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| 2. |
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| 3. |
- Pinches, Simon, et al.
(author)
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Progress in the ITER Integrated Modelling Programme and the use and validation of IMAS within the ITER Members
- 2016
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In: Proceedings of the 26th IAEA Fusion Energy Conference - IAEA CN-234.
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Conference paper (peer-reviewed)abstract
- The ITER Integrated Modelling (IM) Programme will not only support the ITER Project in the development and execution of the ITER Research Plan (IRP) but also provide support for the design basis of the ITER facility during construction, in particular for diagnostics. Strategically, the ITER IM Programme is implemented using expertise and technologies developed within the ITER Members’ research programmes with annual reviews by an Integrated Modelling Expert Group (IMEG) comprised of experts from all the ITER Parties. The Integrated Modelling & Analysis Suite (IMAS) is the software infrastructure that has been developed in response to the needs of the IM Programme and which will support the requirements of both plasma operations and research activities. An agile approach is taken to the development of IMAS and a software management framework consisting of linked issue tracking, source code repositories and a continuous integration server to automatically build and regression test revisions has been established. It is essential that results generated for ITER are reproducible and so software hosting and rigorous version control are prerequisites and already ensured, whilst provenance tracking for handling inputs is still in development. The unifying element of IMAS is its use of a standardized data model capable of describing both experimental and simulation data. This enables the development of workflows that can flexibly use different software components as well as being independent of the device being modelled. This makes IMAS an ideal framework for conducting code benchmarking exercises, such as that within the ITPA Energetic Particle Physics Topical Group on the calculation of fast ion distributions. In this paper, some of the initial software adaptations are presented to indicate the use, and consequent validation, of IMAS within the ITER Members. This has been facilitated by the release this year of a local installer for IMAS which has already allowed installation within the research facilities of the majority of the ITER Members including the EU, India, Japan, Korea and the US. For the most part, these workflows are predictive in nature with interpretive workflows expected to follow from the development of plugins to the IMAS data access tools to securely read and map remote experimental data from existing devices into the standardised data model
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