Speaker
Description
In this contribution, recent results achieved at the FALCON test facility are presented. This versatile facility proves useful for testing continuous wave high-power gyrotrons, but also serves as a platform for testing the transmission line components and RF-loads for ITER and other future facilities. The gyrotron currently under test at SPC is the TH1509UA [1] gyrotron for the Divertor Tokamak Test facility (DTT). This gyrotron, developed through a collaboration between the European GYrotron Consortium (EGYC) and the industrial partner THALES is also the European gyrotron for ITER. EGYC is composed of the following institutions: KIT, the SPC, the NKUA and the ISTP-CNR, with PoliTO and PoliMI added to the consortium. The outcome of this collaborative effort is the confirmation of 1MW long-pulse capability at 170GHz.
The gyrotron TH1509UA operates on the TE_32,9 mode and with a cavity magnetic field of Β_cav = 6.7 T, providing 1 MW CW output power at 170 GHz and with very high Gaussian mode content at the gyrotron window. It is designed based on a diode Magnetron Injection Gun (MIG) and with a single-stage depressed collector. After the successful results of the EU ITER Short-Pulse prototype [2] at the KIT test facility, the EU ITER Long-Pulse prototype TH1509U gyrotron successfully passed the qualification criteria for the ITER project [3]. Here, we present the results of the first DTT pre-series gyrotron, for the DTT facility under construction. In this gyrotron minor design modifications have been integrated, in several steps since the first prototype [1], in the beam tunnel, the high-voltage feedthroughs and depression scheme, the cathode structure and the cavity in order to optimise the power output and suppress unwanted parasitic oscillations.
The preliminary results have shown a power level of 1.03 MW at the gyrotron output window, corresponding to 990 kW at the output of the MOU with an RF power stability of above 95 %. Additionally, an efficiency of 40 % has been demonstrated during five consecutive 100 s pulses.
Scans in several operating parameters, which led to the optimum operating point, will equally be presented. The potential for even higher power performance has been shown in short pulses but not explored in long pulses, which instead focused on demonstrating compliance with the required specifications.
In this gyrotron, the parasitic modes are successfully suppressed such that the maximum output power is reached with parasite-free oscillation.
References
[1] A. Leggieri, et al. “Industrial Qualification of the THALES TH1509U European 170 GHz 1 MW CW Gyrotron”, submitted to IVEC 2024.
[2] T. Rzesnicki et al. “Parasitic-Modes Free, High-Performance Operation of the European 1 MW, 170 GHz Short-Pulse Prototype Gyrotron for ITER”, IRMMW-THz 2023, Montreal, 17-22Sept 2023.
[3] T.P. Goodman, et al., “Tests and Qualification of the European 1 MW, 170 GHz CW Gyrotron in an ITER relevant configuration at SPC”, IRMMW-THZ 2022.
