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Gas flow and related beam losses in the ITER
neutral beam injector
A. Krylov1, R.S. Hemsworth2
1Kurchatov Institute, pl. Kurchatova,1, Moscow 123182, Russia,
2Association EUROATOM-CEA, CEA/DSM/DRFC, CEA-Cadarache13108 St Paul-lez-Durance, France
Abstract: The gas flow in the ITER neutral beam injectors has been studied using a 3D Monte-Carlo code
to define a number of key parameters affecting the design and operation of the injector. This
paper presents the results of calculations of the gas density in the two accelerator concepts
presently considered as options for the ITER injectors, and the resultant stripping losses of the
negative ions during their acceleration to 1 MeV. The sensitivity of the model to various
parameters has been studied, including the gas temperature in the ion source and the subsequent
accommodation by collisions with the accelerator structure, and the degree of dissociation of the
D2 or H2 in the ion source, and subsequent recombination during collisions with the accelerator
structure. Additionally the sensitivity of the losses to details of the beam source design and
operating parameters are examined for the both accelerator concepts.
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Synopsis (pdf)