| 601. |
- Gorini, G, et al.
(författare)
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Neutron spectrometry for plasma rotation
- 1997
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Ingår i: REVIEW OF SCIENTIFIC INSTRUMENTS. - : AMER INST PHYSICS. - 0034-6748. ; 68:1, s. 561-564
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)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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| 602. |
- Gorini, G., et al.
(författare)
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Nuclear scattering effects on the neutron emission in fusion plasmas
- 2008
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Ingår i: Few-body systems. - : Springer Science and Business Media LLC. - 0177-7963 .- 1432-5411. ; 44:1-4, s. 57-60
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Tidskriftsartikel (refereegranskat)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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| 603. |
- Gorini, G, et al.
(författare)
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Proposed Neutron Emission Spectroscopy Diagnostics of Energetic Deutrons in JET rium Plasmas
- 2001
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Ingår i: 7th IAEA TCM on Energetic Particles.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The DT experimental campaign on JET (1997) represented a major step forward for neutron emissionspectroscopy (NES) diagnostics thanks to the high count rate measurements obtained with themagnetic proton recoil (MPR) neutron spectrometer in high fusion yield plasmas [1]. NESmeasurements were made on JET DT plasmas for different heating conditions including thosegenerating energetic deuterons either directly through NB injection, or through ICRH accelerationusing the (D)T minority scheme [2]. A multiple-component model has been developed for analysisof dt neutron spectra that is based on a simplified description of fuel ion velocity distributions fordifferent heating conditions [3,4]. The same model is used here for projections of NES spectra fromJET deuterium plasmas using the dt results as input. This is done on the basis of a system of twocomplementary NES instruments, the TOFOR (Time of Flight - Optimized Rate) [5] and MPRu(Magnetic Proton Recoil Upgrade) spectrometers that are presently proposed for installation onJET [6]. Both spectrometers would record neutron spectra in D plasmas but for different viewinglines. TOFOR would have a “vertical” view, i.e. at an angle of 90° relative to the toroidal magneticfield. This is the same viewing line used for some of the previous dd NES measurements on JET[7]. MPRu would have a “tangential” view, i.e. horizontal (on the equatorial plane) at an angle of47° relative to the toroidal magnetic field and opposite to the beam injection direction. This is thesame viewing line used for the 1997 dt measurements using the magnetic proton recoil (MPR)spectrometer.Projections of dd neutron spectra under the assumptions above are used here for an assessmentof the performance and requirements of NES as a diagnostic of energetic deuterons in JET.
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| 604. |
- Gorini, G, et al.
(författare)
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Relationship between neutron yield rate of tokamak plasmas and spectrometer measured flux for different sight lines
- 2011
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Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 0034-6748 .- 1089-7623. ; 82:3, s. 033507-
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Tidskriftsartikel (refereegranskat)abstract
- A parametric relationship between total neutron yield rate and collimated fluxes related to the brightness (B) of plasma chords (lambda) is developed for different emissivity distributions of tokamak plasmas. Specifically, the brightness was expressed as a function of chord coordinates of radial position using a simple model for the emissivity profiles of width parameter w. The functional brightness dependence B(lambda,w) was calculated to examine the relationship between measured flux and deduced yield rate, and its plasma profile dependence. The results were used to determine the chord range of minimum profile sensitivity in order to identify the preferred collimator sight for the determination of yield rate from neutron emission spectroscopy (YNES) measurements. The YNES method is discussed in comparison to conventional methods to determine the total neutron yield rates and related plasma fusion power relying on uncollimated flux measurements and a different calibration base for the flux-yield relationship. The results have a special bearing for tokamaks operating with both deuterium and deuterium-tritium plasmas and future high power machines such as for ITER, DEMO, and IGNITOR.
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| 605. |
- Hellesen, Carl, et al.
(författare)
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Validation of TRANSP Simulations Using Neutron emission Spectroscopy with Dual Sight Lines
- 2008
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Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 0034-6748 .- 1089-7623. ; 79:10, s. 10E510-
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Tidskriftsartikel (refereegranskat)abstract
- A method to generate modeled neutron spectra from bulk and fast ion distributions simulated by TRANSP has been developed. In this paper, modeled data generated from fuel ion distrubutions modeled with TRANSP is compared to measured data from two neutron spectrometers with different lines of sight; TOFOR with a radial one and the MPRu with a tangential one. The information obtained from the analysis of the measured neutron spectra such as the relative intensity of the emission from different ion populations places additional constraints on the simulation and can be used to adjust the parameters of the simulation.
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| 606. |
- Kaerlev, L, et al.
(författare)
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The importance of smoking and medical history for development of small bowel carcinoid tumor: a European population-based case-control study
- 2002
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Ingår i: Cancer Causes and Control. - 1573-7225. ; 13:1, s. 27-34
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Little is known about the etiology of small bowel carcinoid tumor (SBC), but a few studies have pointed to certain medical and lifestyle factors as potential risk factors. This study aims to evaluate these findings and to identify new associations. Methods: A population-based European multicenter case-control study was conducted from 1995 through 1997. Incident histologically verified 35-69 year-old SBC cases (n = 99) and 3335 controls were recruited; 84 cases and 2070 controls were interviewed. Results: Ever being a smoker was associated with SBC (odds ratio = 1.9; 95% confidence interval 1.1-3.2) and increased risk estimates were seen for all smoking categories. SBC was associated with previous gallstone disease and ovariectomy, but only when these conditions occurred within two years prior to the SBC diagnosis. No association was seen for a history of cholecystitis, liver cirrhosis, ulcerative disease, or Crohn's disease. Intake of alcoholic beverages - as well as medical treatments with radioactive substances, hormones, or corticosteroid tablets - were not associated with SBC. Conclusions: This study indicates that tobacco smoking is a risk factor for SBC. The associations with gallstone and ovarian diseases may be due to enhanced medical surveillance during the early phase of the cancer disease.
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| 607. |
- Kallne, J, et al.
(författare)
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Feasibility of neutron spectrometry diagnostic for the fuel ion density in DT tokamak plasmas
- 1997
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Ingår i: REVIEW OF SCIENTIFIC INSTRUMENTS. - : AMER INST PHYSICS. - 0034-6748. ; 68:1, s. 581-584
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The neutron wall emission (WE) background is a crucial element of neutron spectrometry as a fuel density diagnostic for burning deuterium-tritium fusion plasmas in tokamaks. WE spectra have been studied based on MCNP neutron transport calculations applied
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| 608. |
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| 609. |
- Nocente, M, et al.
(författare)
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Calculated neutron emission spectrum with knock-on effects for RF heated (He-3)D plasmas
- 2011
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 51:6, s. 063011-
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Tidskriftsartikel (refereegranskat)abstract
- The neutron emission from (He-3)D plasmas with RF heating is calculated using a model that includes supra-thermal (knock-on) components of the deuteron population. The RF generation of fast He-3 ions is described and the knock-on components were determined with the help of newly derived He-3 + d scattering cross sections. Results are presented on the neutron emission spectrum and its contributions from different deuteron velocity components. It is shown that knock-on leaves an observable feature in the spectrum with a clear dependence on absorbed RF power. The importance of the nuclear interaction in the elastic cross section is demonstrated. The results represent a step forward in the use of neutron emission spectroscopy to diagnose fusion plasmas with minority supra-thermal components in their fuel ion composition.
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| 610. |
- Nocente, M., et al.
(författare)
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Cross section of the d + He-3 -> alpha plus p reaction of relevance for fusion plasma applications
- 2010
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 50:5, s. 055001-
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Tidskriftsartikel (refereegranskat)abstract
- The cross section of the d + He-3 -> alpha + p fusion reaction has been determined with regard to its systematic variation with energy (E-CM) based on the available experimental data. Information is provided on the angular distribution d sigma/d Omega (theta(p), E) at energies up to E-CM = 8.0 MeV and the total cross section sigma(E-CM) for the range E-CM = 3.0-8.0 MeV. The relevance of the presented results for fusion plasmas heated with RF heating of He-3 minority in D and DT plasmas is discussed.
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