TPX/TFTR neutral beam energy absorbers

Abstract

The present beam energy absorbing surfaces on the TFTR neutral beams such as ion dumps, calorimeters, beam defining apertures, and scrapers, are simple water cooled copper plates which were designed to absorb (via their thermal inertia) the incident beam power for two seconds with a five minute cool down interval between pulses. These components are not capable of absorbing the anticipated beam power loading for 1000 second TPX pulses and will have to be replaced with an actively cooled design. While several actively cooled energy absorbing designs were considered, the hypervapotron elements currently being used on the JET beamlines were chosen due to their lower cooling water demands and reliable performance on JET. The authors summarize the size, location (relative to the source) and the peak power requirements of the various beam components.