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Acceleration of cluster and molecular ions by TIARA 3 MV tandem accelerator

2000; Elsevier BV; Volume: 452; Issue: 1-2 Linguagem: Inglês

10.1016/s0168-9002(00)00427-7

1872-9576

Yoichi Saitoh, K. Mizuhashi, Satoshi Tajima,

Diamond and Carbon-based Materials Research

We succeeded in accelerating molecular and cluster ions (B2–4, C2–10, O2, Al2–4, Si2–4, Cu2–3, Au2–3, LiF, and AlO) to MeV energies with high-intensity beam currents by means of a 3 MV tandem accelerator in the TIARA facility. These cluster ions were generated by a cesium sputter-type negative ion source. We tested three types of carbon sputter cathodes in which graphite powder was compressed with different pressures. The pressure difference affected the generating ratio of clusters generated to single atom ions extracted from the source and it appeared that the high-density cathode was suitable. We also investigated the optimum gas pressure for charge exchange in the tandem high-voltage terminal. Clusters of larger size tend to require lower pressure than do smaller ones. In addition, we were able to obtain doubly charged AlO molecular ions.