Neutron emission characterisation at the FN-II Dense Plasma Focus

15th International Congress on Plasma Physics; 13th Latin American Workshop on Plasma Physics

Castillo-Mejía, F.^1 ; Gamboa-De Buen, I.^1 ; Herrera-Velázquez, J.J.E.^1 ; Rangel-Gutiérrez, José^1

Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Ciudad Universitaria, A. P. 70-543, 04511 Coyoacán, D.F., Mexico^1

关键词: Collimated beams;    Dense plasma focus;    Deuterium fusion;    Generation mechanism;    Neutron spectra;    Nuclear track detector;    Photo multiplier tube;    Silver-activation;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/511/1/012021/pdf
DOI  :  10.1088/1742-6596/511/1/012021

来源: IOP

【 摘 要 】

Plasma foci are efficient plasma based neutron sources, when deuterium is used as the filling gas. The dense plasma focus FN-II is a small device (4.7 kJ), in which the emission of deuterium fusion neutrons (2.45 MeV) are studied. The system produces an average neutron yield of (5.3 ± 0.5) × 108neutron/shot in 4π sr at ∼ 350 kA peak discharge current and 2.75 torr deuterium operation. Three methods are currently used; silver activation counters and CR-39 nuclear track detectors, for time integrated and angular distribution studies, and BC 400 scintillators coupled to photomultiplier tubes for spectra studies. In the latter case, we compare signals due to neutron reflections in the laboratory with those obtained with a collimated beam in a paraffin shielded detector. Regarding the angular distribution of the neutron emission, it has been found to have isotropic and anisotropic components, the former giving the largest contribution. Also, the neutron spectrum, measured at 90° of the axis device, is broadened, peaking at energies slightly larger than 2.45 MeV. These can be interpreted as the consequence of coexisting neutron generation mechanisms, which will be discussed in this work. The correlation between neutron and hard X-ray yields is also discussed, and a possible interpretation in terms of different neutron generation mechanisms is attempted. There has also been a dosimetric study of the laboratory with TLD dosimeters, which will be presented in this paper.