I21: an advanced high-resolution resonant inelastic X-ray scattering beamline at Diamond Light Source oleh Ke-Jin Zhou, Andrew Walters, Mirian Garcia-Fernandez, Thomas Rice, Matthew Hand, Abhishek Nag, Jiemin Li, Stefano Agrestini, Peter Garland, Hongchang Wang, Simon Alcock, Ioana Nistea, Brian Nutter, Nicholas Rubies, Giles Knap, Martin Gaughran, Fajin Yuan, Peter Chang, John Emmins, George Howell