Possible future upgrades of the direct-geometry chopper spectrometer 4SEASONS Ryoichi Kajimoto, Mitsutaka Nakamura, Kazuya Kamazawa, Yasuhiro Inamura, Kazuki Iida, Kazuhiko Ikeuchi and Motoyuki Ishikado EPJ Web Conf., 272 (2022) 02007 Published online: 17 November 2022 DOI: 10.1051/epjconf/202227202007