arXiv subjects

Andrea Rigoni Garola

Publications and source records attributed to Andrea Rigoni Garola.

3 recordsLinked to original sources

arXiv2026

Repurposing acquisition devices into trigger-based timing synchronization of breakdown events during MITICA high voltage holding experiments

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 such feature, a dedicated voltage-holding test campaign was conducted throughout 2024 and 2025 using a full-scale mock-up of the beam source. The tests also involved an accurate characterization of the associated breakdown events: vacuum dielectric failures which result in rapid potential drops and generate strong current discharges. This contribution will present a relative time reconstruction architecture based on cost-effective, embedded RedPitaya (Zynq-7000 FPGA) devices repurposed as timing hubs. These nodes function as configurable trigger multiplexers while simultaneously recording trigger signals as transients to facilitate the offline reconstruction of event sequences. The method allows self-calibration through measuring the static intrinsic delays of the optical fibers and internal logics, generating delay offsets to synchronize acquired waveforms across a sparse, connected-graph topology of both acquisition devices and hubs themselves.

physics.comp-ph↗

arXiv2018

A Zynq-based flexible ADC architecture combining real-time data streaming and transient recording

The RFX-mod2 Nuclear Fusion experiment is an upgrade of RFX-mod, shutdown in 2016. Among the other improvements in the machine structure and diagnostics, a larger number of electromagnetic probes (EMs) is foreseen to provide more information about plasma instabilities and to allow an improved real-time plasma control. An Analog to Digital Converter (ADC) architecture able to provide at the same time both transient recording and real-time streaming, as well as FPGA-based time integration of the inputs is foreseen in RFX-mod2. Transient recording provides full speed data acquisition (up to 1 MSample/s) by recording data in local memory and reading memory content after the plasma discharge. Real-time streaming of sub-sampled data is required for active control. The chosen technology is based on the XILINX Zynq architecture that provides in the same chip a multi-core ARM processor tightly coupled to a FPGA. Time critical functions are carried out by the FPGA, such as the management of the circular data buffer, low pass filtering for subsampling of the samples to be streamed and digital integration. Other functions are carried out by the processor, such as the management of the configuration setting, received via TCP/IP or HTTP, the data readout of acquired samples in transient recording buffers and network data streaming of data collected for active real-time plasma control.

physics.ins-det↗

arXiv2018

Evaluation of noise limits of a precision ADC for direct digital signal integration of magnetic measurements

The characterization of laboratory plasma instabilities, magnetic reconnection and turbulence associated phenomena, require the simultaneous signal sampling from arrays of magnetic sensors (hundreds or even thousands) to obtain spatial resolution, with several hundred kHz for time resolution. Magnetic measurements based on pick-up (Mirnov) coil are quite common in experimental pulsed devices for plasma research, thanks to their simplicity and reliability. Being the signal from this type of sensor proportional to the time variation of the magnetic field ($dB/dt$), it has to be time-integrated to recover the instant value of magnetic field. Depending on the required integration time usually either analog integrators or chopped integrators are used. However these solutions tend to limit the frequency bandwidth in the kHz range, they are not easy to design and build, and require additional fast channels to directly acquire the $dB/dt$ signal to recover the plasma dynamic features at higher frequencies. In this paper we evaluate the feasibility of using a direct single channel precision ADC to allow the simultaneous acquisition of $dB/dt$ measurements and to provide the integrated B measurement by means of digital integration on the new RFX-mod2 device. On this purpose we interfaced an existing ADC-module to a Xilinx Zynq FPGA, in order to evaluate the intrinsic noise and to investigate the feasible integration window of this configuration. The result opens the door to a compact, cost-effective and reliable acquisition system, usable for simultaneous real-time control and transient signal recording, scalable from tenths to thousands channels, applicable to a broad class of pulsed plasma experimental devices.

physics.ins-det↗