The pre-séries Gyrotron (1 MW, 170 GHz, 100 s) for the DTT Electron Cyclotron Resonant Heating system has been manufactured and assembled under DTT-THALES specific contract n.1. The commissioning of the pre-séries tube has been performed at the FALCON facility (SPC-EPFL, Lausanne), and the DTT requirements have been demonstrated during the successfully interim FAT held on November 29^th, 2023.

The tests showed a maximum power level of 1.03 MW at the gyrotron output window, corresponding to 990 kW at the output of the Matching Optics Unit, with an RF power stability below 5%. An efficiency exceeding the 40 % has been demonstrated during 100 s pulses. In fig.1 the pre-series tube installed at FALCON facility is shown together with the time evolution of the thermal power and the beam current provided during the test. The performance of the tube will be optimized in the final configuration and the acceptance of this first Gyrotron is foreseen in 2024.

A specific contract n.2 for the procurement of the additional 15 gyrotrons has been signed on December 20^th, 2023, in a Framework contract resulting of the procedure for a Joint Procurement between DTT and F4E. These sources will generate 16 MW of ECH power for the first phase of DTT operation.

The test, successfully passed, represents an important step in the process of creating the DTT HCD system which, with its 45 MW of installed power, represents one of the most important and challenging part of the entire project.

Fig. 1. FALCON facility and thermal power evolution