A new numerical description of the interaction of an ion beam with a magnetized plasma in an ECR-based charge breeding device

Abstract

11] or electron cyclotron resonance ion sources (ECRIS) [12] to the charge breeding process. Both techniques were compared during FP6 [13] in view of the performances expected for EURISOL, and were found to be complementary: among the two, the ECRIS-based charge breeders (ECR-CB) are usually chosen for their high acceptance in terms of injected current and emittance, the reliability, the possibility to operate both in continuous and pulsed mode, and the high charge states produced. A drawback is the presence of contaminants in the extracted beam, that could possibly hide the peaks of the radioactive ions of interest: this effect can be limited by properly treating all the surfaces exposed to vacuum, and by implementing a spectrometer of adequate resolution downstream the charge breeder, as in the case of the SPES project, which will adopt this kind of device [14,15].

PANDORA, a new facility for interdisciplinary in-plasma physics

“…A Matlab code describing the charge breeding process is available at the PANDORA collaboration [65], and will be applied to the case of 7 Be 1+ ions: it has been already applied to the capture of Na and Rb ions, giving an excellent agreement with the experimental data (see figure 17). The code is able to track injected particles inside the plasma, and also to store the locations where they are lost, as previously shown in figure 16 (left).…”

“…More, it is able to give two important informations about the beamplasma interaction: the density map, showing the spatial distribution of the particles captured by the plasma, figure 16(right), and the energy release map, showing the locations where injected particles loose their energy (see figure 13). The former will help us in finding the necessary plasma dimension to properly trap the injected ions, thus reducing losses; the latter will be used to avoid the possible excitation of plasma instability due to the energy released by the injected particles, as described in [65,67] 6 Application as high-intensity X-ray source Operating in overdense-plasma mode, high-intensity and stable X-ray beams (few keV to 100 keV), will be produced, suitable for non-destructive characterization of samples of interest in the Cultural Heritage field. These beams will be extracted in air (or in a helium atmosphere) and fast tuned in order to promote specific energy domains.…”

“…Left side: distribution of ion losses on the plasma chamber wall. Right side: distribution of the particles captured by the plasma[65].…”

Influence of the injected beam parameters on the capture efficiency of an electron cyclotron resonance based charge breeder

“…The applied simulation code has been extensively described elsewhere [10]: it basically simulates the ion beam slowing down and capture by a magnetized plasma, as a consequence of the long range Coulomb collisions with plasma ions. Once inside the plasma, injected ions are subject to a huge number of small angle elastic collisions, leading to thermal equilibrium with plasma ions.…”

Modelling RF-plasma interaction in ECR ion sources

“…The kinetic code solves equation (2) for each simulated particle applying the relativistic Boris scheme [10,14]: the calculation stops as soon as all the particles hit the chamber walls, while at each time step particles positions are stored in a matrix forming a 3D density map. This map is the output of the kinetic code, and, once rescaled to real values, is used as local electron density n e (x,y,z) to compute again the electromagnetic field {E(r), H(r)}.…”