This beamline covers the photon energy ranging from 4 to > 50 eV. It is estimated that the photon flux at the sample position is ~1016 photons/sec with an energy resolution of ~2%. The photon beam is focused by two toriodal CVD-SiC mirrors which face horizontally. Gas cell is placed at the focus point of the first mirror to suppress the higher harmonics. The calculated beam size at sample point is about 1 × 0.06 mm2 (H × V)
This beamline is suitable for experiments requiring high photon flux with low energy resolution. The BL21white light beamline is a gas filtered ultra-high flux with low resolution U9 white-light beamline, providing photon energies from 5 to 50 eV. Two toroidal SiC mirrors are used to focus the photon beam down to 1 × 2 mm. Photon flux of 2 × 1016 has been obtained. Photodissociation, photodesorption, photoionization, or photoluminescence experiments can be conducted possibly in this beam line.