Ceramic-Chromium Hall Sensors for Environments with High Temperatures and Neutron Radiation

Abstract

Ceramic-chromium Hall sensors represent a temperature and radiation resistant alternative to Hall sensors based on semiconductors. Demand for these sensors is presently motivated by the ITER and DEMO nuclear fusion projects. The developed ceramic-chromium Hall sensors were tested up to a temperature of 550 °C and a magnetic field of 14 T. The magnitude of the sensitivity of the tested sensor was 6.2 mV/A/T at 20 °C and 4.6 mV/A/T at 500 °C. The sensitivity was observed to be weakly dependent on a temperature above 240 °C with an average temperature coefficient of 0.014%/°C and independent of the magnetic field with a relative average deviation below the measurement accuracy of 0.086%. A simulation of a neutron-induced transmutation was performed to assess changes in the composition of the chromium. After 5.2 operational years of the DEMO fusion reactor, the transmuted fraction of the chromium sensitive layer was found to be 0.27% at the most exposed sensor location behind the divertor cassette with a neutron fluence of 6.08 × 1025 n/m2. The ceramic-chromium Hall sensors show the potential to be suitable magnetic sensors for environments with high temperatures and strong neutron radiation.

The Comparison of InSb-Based Thin Films and Graphene on SiC for Magnetic Diagnostics under Extreme Conditions

“…This parameter should be correlated with the possibly high value of the Hall coefficient (with minimum temperature dependence) within a possibly wide temperature range. The latest research in the field concerns materials that show the above characteristics in an operating temperature range exceeding 500 °C [ 5 , 42 ].…”

“…The data on the considered sensor platforms are compared to other systems based on the collective data contained in Refs. [ 5 , 42 ]. The current sensitivity is defined as .…”

“…Magnetic field diagnostics have always been discussed in the context of cross-cutting technologies that enable the use of specific devices and components in space and on Earth. However, in recent years, the problem has received increased interest, following the rise of high-temperature electronics [ 1 , 2 , 3 , 4 ] and electronics for extreme environments [ 5 ]. Applications for extreme environments include the defense, oil, gas, automotive, aerospace, and geothermal industries.…”

“…However, maintaining a good sensing performance with sufficient stability in such difficult conditions has remained a challenge for over a decade. Current research on materials capable of stably detecting magnetic fields under extreme conditions in tokamaks focuses mainly on thin films made of chromium [ 5 ], bismuth [ 8 , 9 , 10 ], gold, and antimony [ 11 , 12 ], but III-V compound semiconductors have also been investigated [ 13 , 14 , 15 ]. Furthermore, recent reports have also considered the viability of two-dimensional (2D) materials in the form of quasi-free-standing (QFS) epitaxial Chemical Vapor Deposition (CVD) graphene on semi-insulating silicon carbide (GR/SiC) [ 16 ] or CVD graphene transferred onto a sapphire substrate [ 17 ].…”

Study of Degradation Mechanisms of Strength and Thermal-Physical Properties of Nitride and Carbide Ceramics—Promising Materials for Nuclear Energy

“…The interest in these power units is due to the possibility of their operation at higher temperatures, which significantly increases the reactors’ efficiency, as well as to the use of new types of uranium fuel with higher burnup rates. Meanwhile, the increase in the coolant temperature, as well as the core operating temperature, requires the use of new types of reactor materials that have high melting temperatures (above 2000 °C), as well as good indicators of resistance to external influences, including mechanical and radiation damage [ 5 , 6 , 7 , 8 ]. There are also additional requirements for these materials used as structural materials, concerning safety and resistance to radiation defects and subsequent effects associated with their accumulation in the damaged layer exposed to irradiation, which can be several tens of microns thick [ 9 , 10 , 11 ].…”