The Future Circular Collider (FCC) is being designed to reach h-h collisions at an unprecedented energy level of 100 TeV, about 8 times higher than in today`s Large Hadron Collider (LHC). Because of the increased energy and luminosity during FCC operation, radiation levels will likely exceed several tens of MGy (with >10e17 particles/cm2) inside the FCC experiments, and tens of KGy (with >10e15 particles/cm2) in certain sectors of the FCC tunnel itself. These estimations correspond to factors of 1000 and 100 with respect to the expected conditions at LHC and HL-LHC, respectively. To withstand such a harsh radiation environment special materials and technologies are required, implying strict component selection and development of custom qualification protocols taking into account possible dependencies of the radiation response to different technologies.
A survey of state-of-the-art solid-state devices for radiation measurement showed that current existing technologies are not capable of integrating such radiation levels, as well as of providing viable solutions to build an on-line radiation monitor fulfilling the FCC requirements. For these reasons, a completely novel dosimetry structure is under development as potential solution for Ultra High Dose and Fluence Monitoring. The technology consists of thin film resistive structures deposited on silicon wafers, where sensitivity to displacement damage, measurable in a variation of their electrical properties, can be trimmed by variating geometrical (thickness, W, L) and physical (material) properties of the nanolayers. The devices are fabricated at EPFL Centre of Micronanotechnology, and specific high-fluence irradiation tests (with gamma, protons, neutrons) are being carried out in CERN facilities and outside CERN. Limitations of the existing solid-state dosimeters, as well as a proposal for a new dosimetric technology based on metal thin films are presented.
In a wider scope, the development and characterization of novel devices as described above, as well as experiment and detector components for FCC, need adequate radiation test facilities. The requirements of the FCC community (machine and experiments) in terms of radiation test facilities and the observable shortcomings of the ones currently available at CERN are also presented.