University of Colorado-CLAS, P.O. Box 3000, Boulder, 80307-3000 United States ; National Center for Atmospheric Research, P.O. Box 3000, Boulder, 80307-3000 United States
Oxford University Department of Physics, Parks Road, Oxford, O1X 3PU United Kingdom
Rutherford Appleton Laboratory, Chilton, Didcot, OX11 0QX United Kingdom ; Colorado Research Associates, 3380 Mitchell Lane, Boulder, 80301 United States