Dear bb, can somebody explain to me the exact definitions for detector roll, pitch and yaw? Can they be detector dependent or rather dependent on the beamline setup? Is there a relationship with the goniometer position? Many thanks in advance, Jonathan -- Jonathan Elegheert Ph.D. Student Unit for Structural Biology & Biophysics http://www.lprobe.ugent.be/xray.html Lab for Protein Biochemistry and Biomolecular Engineering Department of Biochemistry & Microbiology Ghent University, Belgium e-mail: [log in to unmask]