PRESENT STATUS OF CHARGE-BREEDING IN KEKCB AT TRIAC

We report a recent experiment about the measurement of wall distribution of ions externally injected for charge‐breeding in an electron cyclotron resonance (ECR) ion source. The ions, radioactive and singly charged 111In, were injected into the ECR ion source (ECRIS) for breeding their charge states at the Tokai Radioactive Ion Accelerator Complex (TRIAC). The residual radioactivity on the wall of the ECR plasma chamber of the source was measured, giving a two‐dimensional distribution of the ions failed to be re‐extracted during charge breeding. The distribution was decomposed, according to azimuthal symmetry, into three components, asymmetric, 120‐degree symmetric, and isotropic ones, whose origins were qualitatively discussed for clarifying ion‐losses in the course of charge breeding in ECRIS.