Abstract
A large majority of insertion device (ID) vacuum sectors on the European Synchrotron Radiation Facility (ESRF) electron storage ring for the production of intense synchrotron radiation are equipped with flat vacuum vessels made of extruded aluminum using a non-evaporable Getter (NEG) coating to reduce the vacuum pressure bump along the chamber during the operation of the accelerator. After the in-situ activation of the sputtered film by bake-out of the vacuum system the NEG pumps gases such as H2, CO and CO2 while CH4 and noble gases are not pumped. Because a low activation temperature for the NEG is necessary to be compatible with the mechanical limitations of the aluminum alloy, the NEG composition of TiZrV has been chosen. During operation of the ESRF electron storage ring a few hundreds of watts of synchrotron radiation fall on the walls of the ID chambers leading to photodesorption and photo-conditioning. The NEG coating is intended to provide distributed pumping and reduced photodesorption to keep the generation of unwanted Bremsstrahlung radiation following the installation of a new vessel low. The deposit of the NEG coating takes place at a dedicated facility in the ESRF.
