Author: Marques, H.P.
Paper Title Page
TUPS001 Upgrade of the ESRF Vacuum System 1515
 
  • M. Hahn, J.C. Biasci, H.P. Marques, A. Meunier
    ESRF, Grenoble, France
 
  The upgrade program of the ESRF concerns in terms of electron storage ring vacuum chambers mainly the insertion device (ID) sectors. Here the length available for the production of intense synchrotron light is being increased from five to six or even seven meters. The presence of canted ID sectors where two independent synchrotron light beams will be produced in the same straight section requires new quadrupole chambers compatible with the new geometry. A number of long insertion device vacuum chambers for the new ID sectors has already been produced by ESRF and coated with non-evaporable getter (NEG) material, a new generation of in vacuum undulators for the extended ID sections are under preparation. This paper outlines the status of the modification of the vacuum system and informs about consequences for the ESRF NEG coating activity and some recent improvements of the vacuum measurement and control system.  
 
TUPS002 Photodesorption Measurements at ESRF D31 1518
 
  • H.P. Marques, G. Debut, M. Hahn
    ESRF, Grenoble, France
 
  Since 1998 exists at ESRF a dedicated beamline for photodesorption measurement from vacuum chambers - D31. The original goal of this installation was to study the wall pumping effect. When exposed to synchrotron radiation surfaces exhibit strong outgassing of the adsorbed gas layer despite UHV conditions. Long term outgassing leads to the depletion of the adsorbed layer and produces a very clean surface which turns the walls of the vacuum chamber into an active pumping surface. The desorption mechanisms can be described by the long standing models of Knotek-Feibelman (KF) and Menzel-Gomer-Redhead – (MGR) which are themselves encompassed under the name of Desorption Induced by Electronic Transitions (DIET). In these models the surface itself plays a fundamental role in the desorption mechanism. At D31 have been tested chambers of stainless steel, aluminum and copper, with or without coatings (e.g. NEG, copper), designed by ESRF and other institutes like ALBA, CERN, ELETTRA and Soleil. Here we review some of the results obtained and outline the future plans of D31.