Compact ultracold neutron source concept for low-energy accelerator-driven neutron sourcesYun Chang Shin, W. Michael Snow, David V. Baxter, Chen-Yu Liu, Dongok Kim, Younggeun Kim and Yannis K. SemertzidisEur. Phys. J. Plus, 136 8 (2021) 882DOI: https://doi.org/10.1140/epjp/s13360-021-01740-1