Q-Wall, a Novel Quartz-Cherenkov Calorimeter Concept

Calorimeters intended to operate in the heavily demanding radiation conditions of future collider detectors and the upgrades of existing large-scale experiments must possess significant radiation resistance and robustness to ensure consistent performance throughout the lifetimes of the experiments. In this context, a novel calorimeter design known as Q-Wall has been developed, utilizing quartz-Cherenkov calorimetry. The Q-Wall design employs a sampling calorimeter structure, alternating between absorber plates (e.g., Fe, Pb, W) and active layers. The active layers feature compact arrays of photomultiplier tubes with either thick quartz windows or fused silica pads optically linked to traditional photodetector windows. In these active elements, charged particles with $\beta\gt 0.685$ emit Cherenkov radiation which directly illuminates the photocathode. This innovative concept offers the potential for a rapid and finely detailed tracking calorimeter suitable for high radiation environments. Here we report on the development of the QWall concept, the construction of the first prototypes and the results of the beam tests with the prototype modules and compare them with electromagnetic shower development simulations with GEANT4.