Calorimeter design-aspects for neutral beam injection on W7-X

Neutral Beam Injection (NBI) is one of the heating systems for Wendelstein 7-X (W7-X). The beam power of the NBI is measured calorimetrically. Using the knowledge gained from ASDEX-Upgrade [1] operation, the complete calorimeter was re-designed. The design-aspects and the necessary improvements for operation on W7-X are described in this paper. The main aspects improved concern: (i) the adapted slope of the winding drum at the lift, (ii) the adjustable acceleration/deceleration ramp and integrated position sensors, (iii) the improvements of panels in the body, (iv) the accessibility for mounting panels, (v) the water-distribution, and (vi) the centering of the body on the support to fix and reproduce the measuring position. The manufacturing is in progress, installation will start in 2011 and the commissioning is scheduled for the end of 2014.