| 601. |
- Giacomelli, Luca, et al.
(author)
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Advanced Neutron Diagnostics for JET and ITER Fusion Experiments
- 2005
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In: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 45, s. 1191-1201
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Journal article (peer-reviewed)abstract
- The diagnostics functions of neutron measurements as well as the roles played by neutron yield monitors, cameras and spectrometers are reviewed. The importance of recent developments in neutron emission spectroscopy (NES) diagnostics is emphasized. Results are presented from the NES diagnosis of the Joint European Torus (JET) plasmas performed with the magnetic proton recoil (MPR) spectrometer during the first deuterium tritium experiment of 1997 and the recent trace tritium experiment of 2003. The NES diagnostic capabilities at JET are presently being enhanced by an upgrade of the MPR (MPRu) and a new 2.5 MeV time-of-flight (TOF) neutron spectrometer (TOFOR). The principles of MPRu and TOFOR are described and illustrated with the diagnostic role they will play in the high performance fusion experiments in the forward programme of JET largely aimed at supporting the International Thermonuclear Experimental Reactor (ITER). The importance of the JET NES effort for ITER is discussed.
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| 602. |
- Giacomelli, L., et al.
(author)
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High rate measurements of the neutron camera and broadband neutron spectrometer at JET
- 2015
-
Conference paper (peer-reviewed)abstract
- The Joint European Torus (JET, Culham, UK) is the largest tokamak in the world. JET has been upgraded over the years and recently it has also become a test facility of the components designed for ITER, the next step fusion machine under construction in Cadarache (France). At JET, the neutron emission profile of Deuterium (D) or Deuterium-Tritium (DT) plasmas is reconstructed using the neutron camera (KN3). In 2010 KN3 was equipped with a new digital data acquisition system (DAQ) based on Field Programmable Gated Array (FPGA). According to specifications, the DAQ is capable of high rate measurements up to 0.5 MCps. A new compact broadband spectrometer (KM12) based on BC501A organic liquid scintillating material was also installed in the same year and implements a similar DAQ as for KN3. This article illustrates the observations on the DAQ high count rate performance of both KN3 and KM12 in the latest JET D plasma experiments related to hybrid scenario and runaway electrons. For the latter, >1 MCps event rate was achieved with consequences on the behavior of the FPGA and on the reliability of the measurements.
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| 603. |
- Giacomelli, L., et al.
(author)
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Neutron Emission Profiles and Energy Spectra Measurements at JET
- 2014
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In: FUSION REACTOR DIAGNOSTICS. - : AIP Publishing LLC. ; , s. 113-116
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Conference paper (peer-reviewed)abstract
- The joint European Torus (JET, Culham, UK) is the largest tokamak in the world. It is devoted to nuclear fusion experiments of magnetic confined Deuterium (D) or Deuterium-Tritium (DT) plasmas. JET has been upgraded over the years and recently it has also become a test facility of the components designed for ITER, the next step fusion machine under construction in Cadarache (France). JET makes use of many different diagnostics to measure the physical quantities of interest in plasma experiments. Concerning D or plasmas neutron production, various types of detectors are implemented to provide information upon the neutron total yield, emission profile and energy spectrum. The neutron emission profile emitted from the JET plasma poloidal section is reconstructed using the neutron camera (KN3). In 2010 KN3 was equipped with a new digital data acquisition system capable of high rate neutron measurements (<0.5 MCps). A similar instrument will be implemented on ITER and it is currently in its design phase. Various types of neutron spectrometers with different view lines are also operational on JET. One of them is a new compact spectrometer (KM12) based on organic liquid scintillating material which was installed in 2010 and implements a similar digital data acquisition system as for KN3. This article illustrates the measurement results of KN3 neutron emission profiles and KM 12 neutron energy spectra from the latest JET D experimental campaign C31.
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| 604. |
- Giacomelli, L., et al.
(author)
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Neutron emission spectroscopy of DT plasmas at enhanced energy resolution with diamond detectors
- 2016
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In: Review of Scientific Instruments. - : AMER INST PHYSICS. - 0034-6748 .- 1089-7623. ; 87:11
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Journal article (peer-reviewed)abstract
- This work presents measurements done at the Peking University Van de Graaff neutron source of the response of single crystal synthetic diamond (SD) detectors to quasi-monoenergetic neutrons of 14-20 MeV. The results show an energy resolution of 1% for incoming 20 MeV neutrons, which, together with 1% detection efficiency, opens up to new prospects for fast ion physics studies in high performance nuclear fusion devices such as SD neutron spectrometry of deuterium-tritium plasmas heated by neutral beam injection.
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| 605. |
- Giacomelli, L., et al.
(author)
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Tomographic analysis of neutron and gamma pulse shape distributions from liquid scintillation detectors at Joint European Torus
- 2014
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In: Review of Scientific Instruments. - : AIP Publishing. - 0034-6748 .- 1089-7623. ; 85:2, s. 023505-
-
Journal article (peer-reviewed)abstract
- The Joint European Torus (JET, Culham, UK) is the largest tokamak in the world devoted to nuclear fusion experiments of magnetic confined Deuterium (D)/Deuterium-Tritium (DT) plasmas. Neutrons produced in these plasmas are measured using various types of neutron detectors and spectrometers. Two of these instruments on JET make use of organic liquid scintillator detectors. The neutron emission profile monitor implements 19 liquid scintillation counters to detect the 2.45 MeV neutron emission from D plasmas. A new compact neutron spectrometer is operational at JET since 2010 to measure the neutron energy spectra from both D and DT plasmas. Liquid scintillation detectors are sensitive to both neutron and gamma radiation but give light responses of different decay time such that pulse shape discrimination techniques can be applied to identify the neutron contribution of interest from the data. The most common technique consists of integrating the radiation pulse shapes within different ranges of their rising and/or trailing edges. In this article, a step forward in this type of analysis is presented. The method applies a tomographic analysis of the 3-dimensional neutron and gamma pulse shape and pulse height distribution data obtained from liquid scintillation detectors such that n/gamma discrimination can be improved to lower energies and additional information can be gained on neutron contributions to the gamma events and vice versa.
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| 606. |
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| 607. |
- Gorini, G, et al.
(author)
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Neutron emission spectrum from anisotropic DT plasmas
- 1999
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In: REVIEW OF SCIENTIFIC INSTRUMENTS. - : AMER INST PHYSICS. - 0034-6748. ; 70:1, s. 1209-1212
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Journal article (other academic/artistic)abstract
- The diagnostic information from fusion neutron energy spectra under anisotropic plasma conditions is investigated analytically and numerically. The ion anisotropy is parametrized by a Maxwellian velocity distribution with different temperatures along (T-p
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| 608. |
- Gorini, G, et al.
(author)
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Neutron spectrometry diagnostic of triton burn-up in deuterium fusion plasmas
- 1997
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In: PLASMA PHYSICS AND CONTROLLED FUSION. - : IOP PUBLISHING LTD. - 0741-3335. ; 39:1, s. 61-71
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Journal article (other academic/artistic)abstract
- Spectrometry measurements of neutrons from triton bum-up can provide information on fast ion confinement in deuterium plasmas. This study concerns the relationship between the burn-up neutron spectrum and the triton slowing-down distribution under classic
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| 609. |
- Gorini, G, et al.
(author)
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Neutron spectrometry for plasma rotation
- 1997
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In: REVIEW OF SCIENTIFIC INSTRUMENTS. - : AMER INST PHYSICS. - 0034-6748. ; 68:1, s. 561-564
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Journal article (other academic/artistic)abstract
- The principles of neutron spectrometry for determination of the toroidal rotation velocity (V-t) of the plasma in tokamaks are discussed. Comparison is made with photon spectroscopy which shows that neutron spectroscopy can be used as a rotation diagnosti
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| 610. |
- Gorini, G., et al.
(author)
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Nuclear scattering effects on the neutron emission in fusion plasmas
- 2008
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In: Few-body systems. - : Springer Science and Business Media LLC. - 0177-7963 .- 1432-5411. ; 44:1-4, s. 57-60
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Journal article (peer-reviewed)abstract
- Ion reactions and elastic scatterings in fusion plasmas of H and He nuclides are discussed as they can be observed in the neutron emission spectrum (NES). New calculations are presented on radio-frequency driven multi-step processes in (HeD)-He-3 plasmas involving knock-on scattering whose relative importance is discussed besides use for new plasma studies.
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