Photon stimulated molecular desorption from a nonevaporable getter (NEG) St 707(R) (SAES Getters(TM)) surface after conditioning and after saturation with isotopic carbon monoxide [cf. nomenclature in Handbook of Chemistry and Physics, 74th edition, edited by D. R. Lide (CRC Press, Boca Raton, 1994)] (CO)-C-13-O-18, has been studied on a dedicated beamline at the EPA ring at CERN. The synchrotron radiation of 194 eV critical energy and with an average photon intensity of similar to 1 x 10(17) photons s(-1) was impinging on the sample at perpendicular incidence. It is found that the desorption yields eta (molecules/photon) of the characteristic gases in an UHV system (hydrogen, methane, carbon monoxide, and carbon dioxide) for a freshly activated NEG and for a NEG fully saturated with (CO)-C-13-O-18 are lower than that of 300degreesC baked stainless steel. (C) 2003 American Vacuum Society.