Velocity-space sensitivity of neutron spectrometry measurements. (15th April 2015)

• Record Type: Journal Article
• Authors: Jacobsen, A.S.; Salewski, M.; Eriksson, J.; Ericsson, G.; Korsholm, S.B.; Leipold, F.; Nielsen, S.K.; Rasmussen, J.; Stejner, M.
• Other Names: collab.
• Is Part Of: Nuclear fusion. Volume 55:Number 5(2015:May)
• Publication Date: 2015-04-15
• Subjects: neutron emission spectrometry -- velocity-space sensitivity -- fast ions -- energetic particles -- plasma diagnostics; Nuclear fusion -- Periodicals; 621.48405
• DOI: 10.1088/0029-5515/55/5/053013
• Languages: English
• ISSNs: 0029-5515

Abstract

Abstract: Neutron emission spectrometry (NES) measures the energies of neutrons produced in fusion reactions. Here we present velocity-space weight functions for NES and neutron yield measurements. Weight functions show the sensitivity as well as the accessible regions in velocity space for a given range of the neutron energy spectrum. Combined with a calculated fast-ion distribution function, they determine the part of the distribution function producing detectable neutrons in a given neutron energy range. Furthermore, we construct a forward model based on weight functions capable of rapidly calculating neutron energy spectra. This forward model can be inverted and could thereby be used to directly measure the fast-ion phase-space distribution functions, possibly in combination with other fast-ion diagnostics. The presented methods and results can be applied to neutron energy spectra measured by any kind of neutron spectrometer and to any neutron yield measurement.