Dealing with post-accelerated electrons in the ITER SINGAP accelerator

The 1 MeV SINGAP 40 A D− accelerator proposed by Europe for the ITER neutral beam injectors [H.P.L. de Esch, R.S. Hemsworth, P. Massmann, Updated physics design ITER-SINGAP accelerator, Fusion Eng. Des. 73 (2005) 329] is expected to produce 2.7 MW of electrons, which leave the accelerator and strike various beamline components, especially the neutraliser. If no changes are made to the design, hot spots with a power density of 3.3 kW/cm2 are expected. This paper provides details on this and proposes a technical solution to deal with these electrons.