Dear Scott, one more (late) addition, J.D. Grunwaldt et al. published a paper last year, in which they described the use of a flow cell for in-situ XAFS in supercritical CO2. These measurements were performed at HASYLAB beamline X1. (Catal. Lett. 90, 221-229 (2003) and Cat. Today, 91-92, 1-5 (2004)) Best regards, Edmund Welter HASYLAB at DESY