[1] Ctr Univ Paris Sud, Utilisat Rayonnement Electromagnet Lab, F-91405 Orsay, France
[2] CEA, Inst Natl Sci & Tech Nucl, F-91191 Gif Sur Yvette, France
[3] Ctr Univ Paris Sud, CNRS, Lab Spect Infrarouge & Raman, F-91405 Orsay, France
[4] Inst Curie, INSERM, U255, F-75248 Paris 05, France
[5] Brookhaven Natl Lab, Natl Synchrotron Light Source, Upton, NY 11974 USA