| 1. |
- Krasilnikov, A., et al.
(författare)
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Evidence of 9 Be + p nuclear reactions during 2ω CH and hydrogen minority ICRH in JET-ILW hydrogen and deuterium plasmas
- 2018
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 58:2
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Tidskriftsartikel (refereegranskat)abstract
- The intensity of 9Be + p nuclear fusion reactions was experimentally studied during second harmonic (2ω CH) ion-cyclotron resonance heating (ICRH) and further analyzed during fundamental hydrogen minority ICRH of JET-ILW hydrogen and deuterium plasmas. In relatively low-density plasmas with a high ICRH power, a population of fast H+ ions was created and measured by neutral particle analyzers. Primary and secondary nuclear reaction products, due to 9Be + p interaction, were observed with fast ion loss detectors, γ-ray spectrometers and neutron flux monitors and spectrometers. The possibility of using 9Be(p, d)2α and 9Be(p, α)6Li nuclear reactions to create a population of fast alpha particles and study their behaviour in non-active stage of ITER operation is discussed in the paper.
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| 2. |
- Bombarda, F., et al.
(författare)
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Runaway electron beam control
- 2019
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Ingår i: Plasma Physics and Controlled Fusion. - : IOP Publishing. - 1361-6587 .- 0741-3335. ; 61:1
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Tidskriftsartikel (refereegranskat)
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- 2018
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 58:1
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Forskningsöversikt (refereegranskat)
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| 24. |
- Joffrin, E., et al.
(författare)
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Overview of the JET preparation for deuterium-tritium operation with the ITER like-wall
- 2019
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 59:11
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Forskningsöversikt (refereegranskat)abstract
- For the past several years, the JET scientific programme (Pamela et al 2007 Fusion Eng. Des. 82 590) has been engaged in a multi-campaign effort, including experiments in D, H and T, leading up to 2020 and the first experiments with 50%/50% D-T mixtures since 1997 and the first ever D-T plasmas with the ITER mix of plasma-facing component materials. For this purpose, a concerted physics and technology programme was launched with a view to prepare the D-T campaign (DTE2). This paper addresses the key elements developed by the JET programme directly contributing to the D-T preparation. This intense preparation includes the review of the physics basis for the D-T operational scenarios, including the fusion power predictions through first principle and integrated modelling, and the impact of isotopes in the operation and physics of D-T plasmas (thermal and particle transport, high confinement mode (H-mode) access, Be and W erosion, fuel recovery, etc). This effort also requires improving several aspects of plasma operation for DTE2, such as real time control schemes, heat load control, disruption avoidance and a mitigation system (including the installation of a new shattered pellet injector), novel ion cyclotron resonance heating schemes (such as the three-ions scheme), new diagnostics (neutron camera and spectrometer, active Alfven eigenmode antennas, neutral gauges, radiation hard imaging systems...) and the calibration of the JET neutron diagnostics at 14 MeV for accurate fusion power measurement. The active preparation of JET for the 2020 D-T campaign provides an incomparable source of information and a basis for the future D-T operation of ITER, and it is also foreseen that a large number of key physics issues will be addressed in support of burning plasmas.
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| 26. |
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- 2018
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 58:9
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Tidskriftsartikel (refereegranskat)
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| 27. |
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| 28. |
- Birch, J., et al.
(författare)
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Multi-Grid boron-10 detector for time-of-flight spectrometers in neutron scattering science
- 2015
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Ingår i: 2015 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2015. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781467398626
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Konferensbidrag (refereegranskat)abstract
- The Multi-Grid (MG) detector has been introduced at ILL and developed by a collaboration between ILL, ESS and Linkoping University. This detector design addresses the severely decreased availability of He3, in particular for neutron scattering instruments with large-area detectors, such as time-of-flight neutron spectrometers at ESS and other facilities. The MG detector is based on thin converter films of boron-10 carbide arranged in layers orthogonal to the incoming neutrons. The design of the detector provides position resolution, efficiency competitive with He3 and a strong gamma rejection capability. This paper presents the MG large-area (2.4m2) demonstrator and the progress made in order to meet the needs of production of B4C-coated layers, mechanical parts and assembly on a scale similar to that of the final detectors for ESS. A particular effort was made to produce aluminium detector parts with a low alpha background, successfully reducing the background rate to acceptable levels. Following the IN5 demonstrator, a compact prototype has been designed in order to finalise the electronic readout to be used at the ESS instruments equipped with the MG.
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| 29. |
- Anastasopoulos, M., et al.
(författare)
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Multi-Grid detector for neutron spectroscopy : Results obtained on time-of-flight spectrometer CNCS
- 2017
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Ingår i: Journal of Instrumentation. - : IOP PUBLISHING LTD. - 1748-0221. ; 12:4
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Tidskriftsartikel (refereegranskat)abstract
- The Multi-Grid detector technology has evolved from the proof-of-principle and characterisation stages. Here we report on the performance of the Multi-Grid detector, the MG.CNCS prototype, which has been installed and tested at the Cold Neutron Chopper Spectrometer, CNCS at SNS. This has allowed a side-by-side comparison to the performance of 3He detectors on an operational instrument. The demonstrator has an active area of 0.2 m2. It is specifically tailored to the specifications of CNCS. The detector was installed in June 2016 and has operated since then, collecting neutron scattering data in parallel to the He-3 detectors of CNCS. In this paper, we present a comprehensive analysis of this data, in particular on instrument energy resolution, rate capability, background and relative efficiency. Stability, gamma-ray and fast neutron sensitivity have also been investigated. The effect of scattering in the detector components has been measured and provides input to comparison for Monte Carlo simulations. All data is presented in comparison to that measured by the 3He detectors simultaneously, showing that all features recorded by one detector are also recorded by the other. The energy resolution matches closely. We find that the Multi-Grid is able to match the data collected by 3He, and see an indication of a considerable advantage in the count rate capability. Based on these results, we are confident that the Multi-Grid detector will be capable of producing high quality scientific data on chopper spectrometers utilising the unprecedented neutron flux of the ESS.
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| 31. |
- Birch, Jens, et al.
(författare)
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(B4C)-B-10 Multi-Grid as an Alternative to He-3 for Large Area Neutron Detectors
- 2013
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Ingår i: IEEE Transactions on Nuclear Science. - 0018-9499 .- 1558-1578. ; 60:2, s. 871-878
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Tidskriftsartikel (refereegranskat)abstract
- Despite its present shortage, He-3 continues to be the most common neutron converter for detectors in neutron scattering science. However, it is obvious that the development of large area neutron detectors based on alternative neutron converters is rapidly becoming a matter of urgency. In the technique presented here, grids each comprising 28 (B4C)-B-10 layers ( each 1 mu m thick) are used to convert neutrons into ionizing particles which are subsequently detected in proportional gas counters. The total active area of the prototype is 8 cm x 200 cm. To instrument this detector 4.6 m(2) of B-10-enriched boron carbide were coated onto aluminium blades using a DC magnetron sputtering machine. Characterization of the prototype showed neutron efficiency to be epsilon(n) = 46.8% for 2.5 angstrom neutrons, which is in line with expectations from MC simulation. This result demonstrates the potential of this technique as alternative to He-3-based position sensitive detectors.
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| 32. |
- Birch, Jens, et al.
(författare)
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In-beam test of the Boron-10 Multi-Grid neutron detector at the IN6 time-of-flight spectrometer at the ILL
- 2014
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Ingår i: INTERNATIONAL WORKSHOP ON NEUTRON OPTICS AND DETECTORS (NOPandD 2013). - : IOP Publishing: Conference Series / Institute of Physics (IoP).
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Konferensbidrag (refereegranskat)abstract
- A neutron detector concept based on solid layers of boron carbide enriched in 1 B has been in development for the last few years as an alternative for He-3 by collaboration between the ILL, ESS and Linkoping University. This Multi-Grid detector uses layers of aluminum substrates coated with (B4C)-B-10 on both sides that are traversed by the incoming neutrons. Detection is achieved using a gas counter readout principle. By segmenting the substrate and using multiple anode wires, the detector is made inherently position sensitive. This development is aimed primarily at neutron scattering instruments with large detector areas, such as time-of-flight chopper spectrometers. The most recent prototype has been built to be interchangeable with the He-3 detectors of IN6 at ILL. The 1 B detector has an active area of 32 x 48 cm(2). It was installed at the IN6 instrument and operated for several weeks, collecting data in parallel with the regularly scheduled experiments, thus providing the first side-by-side comparison with the conventional He-3 detectors. Results include an efficiency comparison, assessment of the in-detector scattering contribution, sensitivity to gamma-rays and the signal-to-noise ratio in time-of-flight spectra. The good expected performance has been confirmed with the exception of an unexpected background count rate. This has been identified as natural alpha activity in aluminum. New convertor substrates are under study to eliminate this source of background.
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| 33. |
- Hagert, C., et al.
(författare)
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Chronic Active Arthritis Driven by Macrophages Without Involvement of T Cells : A Novel Experimental Model of Rheumatoid Arthritis
- 2018
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Ingår i: Arthritis & Rheumatology. - Hoboken : Wiley. - 2326-5191 .- 2326-5205 .- 1529-0131. ; 70:8, s. 1343-1353
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To develop a new chronic rheumatoid arthritis model that is driven by the innate immune system. METHODS: Injection of a cocktail of 4 monoclonal antibodies against type II collagen, followed on days 5 and 60 by intraperitoneal injections of mannan (from Saccharomyces cerevisiae), was used to induce development of chronic arthritis in B10.Q mice. The role of the innate immune system as compared to the adaptive immune system in this arthritis model was investigated using genetically modified mouse strains. RESULTS: A new model of chronic relapsing arthritis was characterized in B10.Q mice, in which a persistently active, chronic disease was found. This relapsing disease was driven by macrophages lacking the ability to mount a reactive oxygen species response against pathogens, and was associated with the classical/alternative pathway, but not the lectin pathway, of complement activation. The disease was independent of Fcgamma receptor type III, and also independent of the activity of adaptive immune cells (B and T cells), indicating that the innate immune system, involving complement activation, could be the sole driver of chronicity. CONCLUSION: Chronic active arthritis can be driven innately by macrophages without the involvement of T and B cells in the adaptive immune system.
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| 34. |
- Khaplanov, Anton, et al.
(författare)
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Investigation of gamma-ray sensitivity of neutron detectors based on thin converter films
- 2013
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Currently, many detector technologies for thermal neutron detection are in development in order to lower the demand for the rare He-3 gas. Gas detectors with solid thin film neutron converters readout by gas proportional counter method have been proposed as an appropriate choice for applications where large area coverage is necessary. In this paper, we investigate the probability for gamma-rays to generate a false count in a neutron measurement. Simulated results are compared to measurement with B-10 thin film prototypes and a He-3 detector. It is demonstrated that equal gamma-ray rejection to that of He-3 tubes is achieved with the new technology. The arguments and results presented here are also applicable to gas detectors with converters other than solid B-10 layers, such as Li-6 layers and (BF3)-B-10 gas.
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| 35. |
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| 36. |
- Piscitelli, F., et al.
(författare)
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Study of a high spatial resolution B-10-based thermal neutron detector for application in neutron reflectometry: the Multi-Blade prototype
- 2014
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Although for large area detectors it is crucial to find an alternative to detect thermal neutrons because of the He-3 shortage, this is not the case for small area detectors. Neutron scattering science is still growing its instruments' power and the neutron flux a detector must tolerate is increasing. For small area detectors the main effort is to expand the detectors' performances. At Institut Laue-Langevin (ILL) we developed the Multi-Blade detector which wants to increase the spatial resolution of He-3-based detectors for high flux applications. We developed a high spatial resolution prototype suitable for neutron reflectometry instruments. It exploits solid B-10-films employed in a proportional gas chamber. Two prototypes have been constructed at ILL and the results obtained on our monochromatic test beam line are presented here.
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| 37. |
- Sacchetti, F., et al.
(författare)
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He-3-free neutron detectors and their applications
- 2015
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Ingår i: The European Physical Journal Plus. - : Springer Science and Business Media LLC. - 2190-5444. ; 130:3
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Tidskriftsartikel (refereegranskat)abstract
- The shortage of He-3 isotope to be used as optimum neutron absorber in various neutron detection applications is considered. Here we present some general requirements in different applications to introduce more specialized papers which describe recent progresses. Considering that the neutron detection is important in a very wide range of applications we cannot be exhaustive but we describe the most relevant applications which are expected to be important in the next decades.
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