XCETs and CEDARs

8 DECEMBER,2020 | By Markus Brugger

Particle identification is vital for many users and experiments and is under our responsibility for what concerns the Cherenkov effect-based detectors XCET and CEDAR (XCED). The operation principle of these devices is based on the detection of Cherenkov radiation emitted by a relativistic charged particle traversing a medium with a speed higher than the speed of light in that medium (Einstein is indeed still right ), allowing for particle identification as the intensity and angular distribution of emitted Cherenkov photons relates to the particle momentum (mass, velocity) as a function of the radiator gas type and pressure. However, the number of spare parts for these monitors is critical and many subsystems required urgent consolidation, such as the gas system of the XCET, which does not comply with current safety regulations. For the big brother, the CEDAR, today we do not even have an operational spare leading to a possible showstopper for NA62 operation in case of failure. For the XCETs, initially triggered by the new beamlines for the neutrino platform, then a requirement for the East-Area renovation project and now also for the remaining North Area devices, a long-term consolidation effort has been launched. 2020 bore several surprises, but thanks to many of you an equal number of solutions could also be found. Aiming for higher pressures to extend the energy range, XCET tomography results demonstrated that castings cannot be assumed to be of a consistent quality, as previously thought. However, a detailed analysis and effective collaboration together with HSE, allowed for finding a pragmatic approach bringing these essential elements again back on track for the EAR. For the CEDARs, having successfully received the green light in the last MTP exercise for producing an operational spare and continuing the CEDAR upgrade studies, for the first time since many years we have opened a CEDAR and started a detailed reverse engineering process and first preparations for a future production of an operational spare. In parallel, for NA62 upgrade studies were also launched, aiming to exchange the CEDAR gas type and increase its resolution capabilities. Physics at play to allow for new Physics to be detected. Many thanks to all involved teams and people and let us aim for a visit in the North Area.