1. Laboratório Nacional de Luz Síncrotron, C.P. 6192, 13084-971 Campinas SP, Brazil, Instituto de Física Gleb Wataghin, UNICAMP, C.P. 6165, 13083-970 Campinas SP, Brazil, and Measurement Standards Laboratory of New Zealand, P.O. Box 31-310, Lower Hutt, New Zealand