Ultra High Fluence Radiation Monitoring Technology for the Future Circular Collider at CERN

The future circular collider (FCC) is foreseen as the next-generation ~100-km long synchrotron to be built in the Geneva area starting 2050. This machine is expected to reach an energy level of 100 TeV generating unprecedented radiation levels >100 times higher than in today’s large hadron collider (LHC). Current radiation monitoring system, like the RADMONs employed in the LHC, will not be capable to function and withstand this harsh environment. The development of a new ultrahigh fluence and dose radiation sensor is a key element to allow irradiation tests of FCC equipment and, at a later stage, to monitor radiation levels in the FCC itself. In this paper, we present an innovative dosimetry solution based on thin layers of metals, which resistivity is shown to increase significantly due to the accumulated displacement damage. After describing the fabrication techniques used to manufacture these radiation-dependent resistors, we show and discuss the results of the irradiation experiments carried out with neutrons (up to $10^{18}$ n/cm$^2$ at the JSI TRIGA reactor) and with protons (up to $5.2 \times 10^{16}$ p/cm$^2$ at CERN IRRAD Facility) to validate the proposed concept of possible ultrahigh fluence FCC dosimeter.