Objective

This international conference aims to share the latest scientific results in the emerging field of high-resolution X-ray spectroscopy enabled by X-ray microcalorimeters. It seeks to foster an integrated discussion on both the technological development and scientific applications of precision spectroscopy, with an eye toward shaping future research directions from a global perspective. The conference will provide a platform for in-depth discussions on the current status and future prospects of this field, contributing to the steady progress of high-resolution X-ray spectroscopy over the medium and long term. It also aims to promote international collaboration, detector development, and knowledge exchange in anticipation of future space-based observations. By bringing together experts from a wide range of disciplines -- including space engineering and astronomy, on-ground instrumentation, and applied physics -- the conference is expected to explore new directions for technological advancement and instrument innovation, ultimately driving the next stage of scientific discovery. 

Background

On September 7, 2023, we successfully launched the seventh Japanese X-ray astronomy satellite, XRISM, which continues to operate smoothly in orbit. XRISM is a collaborative project led by JAXA's Institute of Space and Astronautical Science (ISAS), in partnership with NASA, ESA, and several Japanese universities. The satellite's flagship instrument, Resolve, is a non-dispersive soft X-ray spectrometer equipped with an X-ray microcalorimeter at the focal plane of an X-ray mirror, offering exceptionally high energy resolution. Resolve shares nearly the same specifications as the Soft X-ray Spectrometer (SXS) aboard the previous Hitomi satellite, launched in 2016.

Over a year after launch, Resolve continues to deliver high-quality observations, and its data are rapidly being published. At the heart of this capability lies the X-ray microcalorimeter, which operates at an ultra-low temperature of 50 mK. This creates a highly stable thermal environment, allowing for the precise measurement of temperature increase caused by the absorption of individual X-ray photons. This technology is opening a new frontier in high-precision X-ray spectroscopy from space.

Resolve’s observations are already advancing our understanding of the motion and physical states of hot gas, as well as the elemental composition -- including rare elements -- across various celestial objects. These insights are helping to deepen our knowledge of cosmic structure and the evolution of astronomical systems. At the same time, interpreting these observations requires reliable physical parameters, making it increasingly important to reproduce space-like environments in the laboratory. The emerging field of laboratory astrophysics plays a key role in validating and interpreting space-based data.

To further expand this new scientific domain of precision X-ray spectroscopy, foundational research and long-term roadmaps for future instrumentation are essential. Development of next-generation detectors -- particularly Transition Edge Sensors (TES) -- is progressing rapidly, not only for space-based applications but also in fields such as plasma and material physics or exotic atom spectroscopy. Efforts to unlock the full potential of microcalorimeter technology -- through advancements in fabrication techniques, performance improvements, and rigorous evaluation -- will be crucial for sustaining and accelerating the evolution of high-resolution X-ray spectroscopy in the years to come.