Modified perveance law for neutral-beam ion sources
The perveance law for ion sources is modified, based on experimental results gained during the conditioning phase of three multi-aperture ion sources for neutral-beam injection into TEXTOR. The ion sources are modified JET PINIs with a three-grid accel-decel extraction system designed for 55 kV, 88A, 4.8 MW, operated in hydrogen. Best agreement of the perveance law with the experimental data is achieved when the measured ion species mixture is used and, additionally, when the total width of the first acceleration gap is enlarged by a distance term taking the effect of distortion of the electrical field lines at the decel grid into account. At perveance matched conditions, i.e. minimum beam divergence, the optimum value is found to be 0.8r, where r is the aperture radius of the decel grid. The species fractions are measured by optical and magnetic spectrometry.
Bibliographic Reference: Article: Rev.Sci.Instrum., Vol. 60 (1989) No. 9, pp. 2879-2882
Record Number: 199010422 / Last updated on: 1994-12-01
Original language: en
Available languages: en