The operational performance of the NIJI-III superconducting storage ri
ng has been studied with particular attention focused on the Vacuum pe
rformance of the cold-bore chamber. Photon-stimulated gas desorption i
n the cold-bore chamber was examined after commissioning the storage r
ing. It was confirmed that the photon-stimulated gas desorption due to
diffuse reflection of synchrotron radiation at the absorber was not d
ominant in the gas desorption when the electron beam was accumulated i
n the storage ring.