Construction of the High Granularity Dual-readout Calorimeter Prototype for Future High Energy Physics Experiments*

The advent of the dual-readout calorimeter (DREAM) marked a significant leap forward in the understanding and advancement of calorimetry. As the field progresses, the future of calorimetry necessitates the development of detectors that offer both high spatial and time granularity, as well as exceptional energy resolution for the future high-energy physics experiments. We present the design and construction of a high-granularity dual-readout calorimeter prototype, known as HG-DREAM, that addresses these critical needs. By employing Cherenkov and scintillating fibers, we effectively capture fluctuations in the electromagnetic energy fraction within hadronic showers, enhancing measurement accuracy. Furthermore, we have enhanced the detector's capabilities by integrating fast silicon photomultipliers (SiPMs) with finer transverse and longitudinal segmentation by precision timing. This advanced configuration allows us to image hadronic showers with unprecedented granularity, significantly improving the resolution and performance of the calorimeter. Our prototype represents a meaningful step towards the realization of next-generation calorimeters with improved imaging capabilities and energy reconstruction capabilities.