Beamline 10.0.1 has been delivering photons for over 20 years as it is one of the first beamlines commissioned at the Advanced Light Source (
http://www.sciencedirect.com/science/article/pii/016890029290539G). This is an undualtor beamline with the spherical grating monochromator (SGM) which at the time of its design and construction was a proven passkey to achieving a high resolving power. Indeed, in 1996 measurements of the double-excitation resonance in helium performed at the beamline (
http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.77.3086 ) demonstrated a resolving power of 64 000 at 64.1 eV which back then was a world record.