Oxygen-free high-conductivity copper is a more suitable material than aluminum alloy and stainless steel, which are used in many electron storage rings, because the former has a higher thermal conductivity, a larger shielding power for high-energy synchrotron radiation, and a lower photodesorption coefficient. A copper beam duct was fabricated and an aluminum alloy duct was replaced by the copper duct in the Photon Factory (PF) ring to receive intense synchrotron radiation (SR) from a super-conducting wiggler which can emit radiation with 20 keV critical energy. This installation can also help us verify whether or not. the experimental results concerning photodesorption obtained in the beamline can be re-obtained in a practical ring. The copper duct exhibited good vacuum characteristics, and the surface treatment that we adopted in both the experimental duct and real duct has been demonstrated to be suitable for reducing the photodesorption yields. The final photodesorption yields of the copper duct have been less than 10-6 molecules/photon.