China makes first advanced cryomodule for nuclear research facility

China has achieved a significant breakthrough in particle accelerator technology by developing its first high-performance double-spoke superconducting cavity cryomodule. This advancement supports Phase II of the China Spallation Neutron Source (CSNS-II), a leading facility for nuclear physics and advanced materials research. The two superconducting cavities demonstrated impressive acceleration strengths of 12.8 and 15.2 megavolts per meter during pulsed operation tests. Key technical improvements included reducing peak electric fields, preventing multipacting, and simplifying manufacturing, complemented by a novel chemical polishing technique that enhanced cavity quality factors (Q-values exceeding 3.4×10¹⁰ at 9 MV/m). The cryomodule design incorporates carbon fiber tie rods to minimize heat loss and allow precise cavity positioning under cryogenic conditions, alongside a carefully controlled cooling process to maintain high performance. The CSNS, the world’s fourth pulsed accelerator-driven neutron source, reached its initial design power of 100 kilowatts in 2020