HECATE - A long-lived particle detector concept for the FCC-ee or CEPC Marcin Chrząszcz, Marco Drewes and Jan Hajer Eur. Phys. J. C, 81 6 (2021) 546 Published online: 25 June 2021 DOI: 10.1140/epjc/s10052-021-09253-y