We report results on experiments using combined laser and synchrotron radia
tion. Picosecond laser pulses at 800 nm are used to induce surface photovol
tage transients in p-type Si samples. A two-component decay is observed. Th
e fast component of decay provides a direct measure of synchrotron soft X-r
ay pulse durations. (C) 2001 Elsevier Science B.V. All rights reserved.