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| 2. |
- Gatu Johnson, Maria, 1978-, et al.
(författare)
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The TOFOR neutron spectrometer and its first use at JET
- 2006
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Ingår i: Review of Scientific Instruments. - American Institute of Physics : AIP Publishing. - 0034-6748 .- 1089-7623. ; 77:10E702, s. 1-3
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Tidskriftsartikel (refereegranskat)abstract
- A time-of-flight neutron spectrometer (TOFOR) has been developed to measure the 2.45 MeV d+d3He+n neutron emission from D plasmas. The TOFOR design features the capability to operate at high rates in the 100 kHz range, data collection with fast time digitizing and storing, and monitoring of the signals from the scintillation detectors used. This article describes the principles of the instrument and its installation at JET and presents preliminary data to illustrate the TOFOR performance as a neutron emission spectroscopy diagnostic.
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| 4. |
- Giacomelli, Luca, et al.
(författare)
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Comparison of neutron emission spectra for D and DT plasmas with auxiliary heating
- 2005
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Ingår i: The European Physical Journal D. - : Springer Science and Business Media LLC. - 1434-6060 .- 1434-6079. ; :33, s. 235-241
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Tidskriftsartikel (refereegranskat)abstract
- The DT experimental campaign on JET (1997) represents a major step forward for neutronemission spectroscopy (NES) diagnostic through the high quality data collected by the Magnetic ProtonRecoil (MPR) spectrometer. These data for different DT plasma heating scenarios were analyzed here todetermine the underlying fuel ion populations which in turn were used to project the 2.5-MeV neutronemission spectra for deuterium plasmas. The results on neutron spectra for DT and D plasmas in thesame conditions were compared in order to determine the plasma information that could be expectedfrom NES diagnosis of D plasmas and the instrumental characteristics that would be required. FutureNES experiments would make dual sight line observations possible and the added diagnostic value is alsoassessed based on the present results.
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| 6. |
- Sjöstrand, Henrik, et al.
(författare)
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Gain stabilization control system of the upgraded magnetic protonrecoil neutron spectrometer at JET
- 2009
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Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 0034-6748 .- 1089-7623. ; 80:6, s. 063505-
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Tidskriftsartikel (refereegranskat)abstract
- Burning plasma experiments such as ITER and DEMO require diagnostics capable of withstanding the harsh environment generated by the intense neutron flux and to maintain stable operating conditions for times longer than present day systems. For these reasons, advanced control and monitoring (CM) systems will be necessary for the reliable operation of diagnostics. This paper describes the CM system of the upgraded magnetic proton recoil neutron spectrometer installed at the Joint European Torus focusing in particular on a technique for the stabilization of the gain of the photomultipliers coupled to the neutron detectors. The results presented here show that this technique provides good results over long time scales. The technique is of general interest for all diagnostics that employ scintillators coupled to photomultiplier tubes.
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| 7. |
- Sjöstrand, Henrik, et al.
(författare)
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Gain stabilization control system of the upgraded magneticproton recoil neutron spectrometer at JET
- 2009
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Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 0034-6748 .- 1089-7623. ; 80:6, s. 063505-
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Tidskriftsartikel (refereegranskat)abstract
- Burning plasma experiments such as ITER and DEMO require diagnostics capable of withstanding the harsh environment generated by the intense neutron flux and to maintain stable operating conditions for times longer than present day systems. For these reasons, advanced control and monitoring (CM) systems will be necessary forthe reliable operation of diagnostics. This paper describes the CM system of theupgraded magnetic proton recoil neutron spectrometer installed at the Joint European Torus focusing in particular on a technique for the stabilization of the gain of thephotomultipliers coupled to the neutron detectors. The results presented here show that this technique provides good results over long time scales. The technique is of general interest for all diagnostics that employ scintillators coupled to photomultiplier tubes.
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| 8. |
- Sjöstrand, Henrik, et al.
(författare)
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Triton burn-up neutron emission in JET low current plasmas
- 2008
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Ingår i: Journal of Physics D. - : IOP Publishing. - 0022-3727 .- 1361-6463. ; 41:11, s. 115208-
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Tidskriftsartikel (refereegranskat)abstract
- The 14 MeV neutron emission from JET deuterium discharges is analysed on the basis of the information on all neutron diagnostics available on JET. This emission is due to the d + t → α + n reaction, mainly, the triton burn-up process, and is used to determine the fast triton confinement. A simplified model for triton burn-up neutron emission has been used and provides an adequate description of the 14 MeV emission. First orbit triton losses are found to amount to 50%, 20% and 10% at Ip = 1 MA, 2 MA and 3 MA, respectively. Neutron emission spectroscopy measurements with the magnetic proton recoil neutron spectrometer have detected a contribution to the 14 MeV emission due to residual tritium. For the selected (low impurity) discharges analysed in this paper 15% of the 14 MeV emission comes from the residual tritium reactions. It is also found that the residual tritium concentration tends to increase with increasing impurity content.
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