HUBS and its pathfinder experiment DIXE

Hot Universe Baryon Surveyor (HUBS) is proposed as a dedicated probe of hot gas in galaxy ecosystems, which is beyond the capabilities of current X-ray observatories but holds a key to understanding galaxy evolution. It employs a non-dispersive spectrometer based on TES microcalorimeters, enabling both high-resolution spectroscopy and imaging. In this contribution, we briefly describe the progress on the development of TES microcalorimeters for HUBS, as well as that of supporting key technologies including frequency-division multiplexing readout electronics, cryocoolers and adiabatic demagnetization refrigerator, and wide-field X-ray optics. We also show the design of a pathfinder experiment (DIXE), which is being considered for inclusion in the science portfolio of the China Space Station, not only to advance the TRLs of the key technologies for HUBS, but to conduct a high-resolution X-ray spectroscopic survey for the first time.