The DTT project includes a complex and extensive diagnostic system. In this framework, reflectometry plays an important role for multiple objectives, such as density profile reconstruction, fluctuations and turbulence studies and a plasma position reconstruction (PPR).

The PPR plays an essential role in the management of experiments as it contributes to the identification of the plasma boundary, identifying, along its “lines of sight”, the largest closed magnetic surface, within a fine error bar (1 cm) and high temporal resolution (1 ms).

PPR-based reflectometers currently operating in major international laboratories are limited to a maximum of two “lines of sight” (ASDEX Upgrade). The system designed for DTT constitutes an important step forward in specific technology, being able to treat multiple lines of sight and to assess their performance.

The project is carried out within a broad collaboration involving both Italian laboratories (ENEA-Frascati, RFX-Padova, INFN-Catania) and European institutions (IPFN/IST-Lisbon-Portugal, Université de Lorraine-France) with the support of EUROFusion (Enabling Research project TEC.01.IST). An important cooperation comes from also industry (proMetheus/IPVC, Viana do Castelo-Portugal) for the prototype manufacturing.

The first prototype of the antenna to be installed in the high field region of the machine was recently built using 3D printing. Subsequent tests demonstrated the effectiveness of the project, despite the innovative geometry used to respect the stringent local space constraints.

The DTT experience will be invaluable for the design of the future DEMO from many points of view, including integration and assembly problems with the main components of the machine, such as vessel, first wall and cooling system.

Figure 1: Microwave propagation test on the 3D printed antenna prototype

Figure 2: 3D printed antenna mockup