Speaker
Description
A critical requirement for MITICA — a full-scale prototype of the heating Neutral Beam Injectors hosted at the Consorzio RFX Neutral Beam Test Facility for the ITER experiment — is the capability to withstand a continuous voltage of 1MV across the vacuum gaps insulating the beam source from the grounded vessel. To validate this feature, a dedicated voltage-holding test campaign was conducted throughout 2024 and 2025 using a full-scale mock-up of the beam source. Tests involved an accurate characterization of the associated breakdown events: vacuum dielectric failures which result in rapid potential drops and generate strong current discharges.
In order to observe such phenomena, several current probes were deployed at different key sites of the plant and along the ${\sim}150$m transmission line, acquiring the instantaneous current flowing through all components. To guarantee noise immunity and reliable electrical insulation, battery-powered transient acquisition devices were used; however, this approach limited the options for implementing a precise measurement of the relative delays among acquired signals.
This contribution presents the solution adopted: a time reconstruction architecture based on cost-effective embedded RedPitaya (Zynq-7000 FPGA) devices repurposed as "timing-hubs", which function as configurable trigger multiplexers, capturing trigger signals as transients to facilitate the offline time reconstruction of event sequences. The system features a self-calibration mechanism that measures signal time-of-flight along optical fibers, generating delay offsets to synchronize acquired waveforms across a sparse, connected-graph topology of both acquisition devices and other hubs.
The results obtained encourage to consider this uncomplicated repurposing methodology suitable for similar challenging applications.
| Minioral | Yes |
|---|---|
| IEEE Member | No |
| Are you a student? | No |