Zone for Collecting the Ions of a Given Mass Range in the Plasma Filter of Masses

Abstract

The trajectories of motion for atomic and molecular ions of a given mass range (M = 232...277) in the plasma mass filter, which is currently being developed, are calculated. The influence of the initial conditions (energy, angle, radius) on the ion trajectory to determine the dimensions of the collector for actinides, the so-called “pocket”, is studied. It is shown that the variable component of the radial electric field, tuned to a frequency equal to half the ion cyclotron frequency for M = 238 allows target ions to enter the “pocket”. An analysis of the calculations showed that there are limitations on energy, angle, and radius related to the initial conditions for the ion motion, that must be taken into account when creating the plasma source for the plasma mass filter.

Spatial Separation of the Iones of a Given Mass Range in the Demo-Imitation Separator at the First Turn of Ionic Trajectory

“…For the given parameters such approach at increase of amplitude coefficient k (k = 1, in comparison with k = 0.7 [10]) provides filtering out the target ions onto the collector with kinetic energy at a level of ~300 eV (at ion energy decrease in 1.7 times, in comparison with ~500 eV [9]) that could prevent thermal overload on the ion deposition surface.…”

“…According to our assumptions, in SNF plasma the main components would be the ions of uranium-238. Calculations of ionic trajectories for M = 232...277 show that the variable component of electric field tuned to the frequency, , equal to half the cyclotron frequency for singly charged ions U + (M = 238, B = 0.1 T), with k = 0.7 provide filtering out the target ions onto the collector at the second turn (at guiding center motion in a radial direction) of ionic trajectory [10]:…”

“…In this case, FP ions move along the chamber to the end collector. The length of the collector for target ions is 1 m, with the location along z-axis of the vacuum chamber from 2.5 to 3.5 m, and a height of 0.1 m [10].…”

“…From Figs. 3-5 it follows, that, as well in the case [10], there are limitations on the scatter of the angle, energy and radius related to the initial conditions for the ion motion, that must be taken into account when creating the plasma source. The allowable scatter of the initial values for the ions (M = 232...277), at which their entry into the "pocket"-collector is achieved: energy, W = 5…5.5 eV, angle, = 0...10, radius, r = 0.5...1.5 cm.…”

“…6. Projections of the ion trajectories in r×z plane for М = 270 (k = 1,  = 50…80) In this case, the length of the collector of target ions is 1 m, with a location of 1…2 m along the z-axis of the vacuum chamber, a height of 0.3 m. Thus, the area of ion deposition increases slightly compared to [9,10], but lowering of ion energy at a level of ~300 eV could reduce the thermal load onto deposition surface for target ions about twice.…”