UV emission spectrometer using a non-periodic grating.

A UV emission spectrometer using a non-periodic spherical grating has been designed, which can be attached to the linear or helical undulator beamlines of the HiSOR light source at the Hiroshima Synchrotron Radiation Centre. The useful range of emitted photons from 10 to 100 eV is covered by two gratings with nominal groove spacings of 1/600 and 1/1200 mm. The energy resolution with a 100 micro m entrance slit width and the 1/600 mm grating is better than 0.2 eV below 50 eV.