Test bench for calibration of magnetic field sensor prototypes for COMPASS-U tokamak

0543176 - ÚFP 2022 RIV CH eng J - Journal Article
Torres, Andre - Kovařík, Karel - Markovič, Tomáš - Adámek, Jiří - Ďuran, Ivan - Ellis, R. - Jeřáb, Martin - Řeboun, J. - Turjanica, P. - Weinzettl, Vladimír - Fernandes, H.
Test bench for calibration of magnetic field sensor prototypes for COMPASS-U tokamak.
Fusion Engineering and Design. Roč. 168, July (2021), č. článku 112467. ISSN 0920-3796. E-ISSN 1873-7196
Institutional support: RVO:61389021
Keywords : Frequency response * Magnetic diagnostic * Magnetic sensors * Magnetics * mic * Mineral insulated cables * Tokamak
OECD category: Fluids and plasma physics (including surface physics)
Impact factor: 1.905, year: 2021
Method of publishing: Limited access
https://www.sciencedirect.com/science/article/pii/S092037962100243X?via%3Dihub

Magnetic field sensors are fundamental for control and physics exploitation of fusion devices. Their inductive nature implies high dynamic ranges and a broad bandwidth, thus a precise characterization and calibration of these probes is paramount. COMPASS-U will have a completely new set of magnetic diagnostics, from sensors to data acquisition. Sensors installed in-vessel will operate at 300–500 °C and should survive transients of even higher temperatures and thus materials used should be high-temperature compatible. These design limitations will have an impact on the dynamic range and bandwidth of the sensors, which needs to be reliably quantified, optimally with the same test bench for all sensor types. The first part of this work presents a test bench and the process of how to calibrate the effective area using a large solenoidal coil and frequency response of the magnetic sensor prototypes with a Helmholtz coil. In the second part, test results of the sensor prototypes are presented and discussed in detail. The low-bandwidth sensors made of mineral insulated cable (MIC), intended for plasma control and machine protection, show negligible attenuation up to 10 kHz, sufficient for their role. For fast coils consisting of bare wire wound on ceramic mandrel and Thick Printed Copper (TPC) sensors the negligible attenuation measured below 1 MHz is again sufficient for their intended purpose of detecting fast coherent plasma fluctuations. Resonances introduced by the capacitance of long cables from the vacuum vessel feedthroughs to the data acquisition systems are measured, to model their influence on the signal.
Permanent Link: http://hdl.handle.net/11104/0320447