CrystFEL detector geometry files -------------------------------- The detector geometry is taken from a text file rather than hardcoded into the program. Programs which care about the geometry (indexamajig, pattern_sim and powder_plot) take an argument "--geometry=" (or "-g "), where contains the geometry. CrystFEL's representation of a detector is broken down into one or more "panels", each of which has its own location for the centre of the panel (i.e. the location of the central beam), its own camera length, resolution and so on. Each panel fits into the overall image taken from the HDF5 file, defined by minimum and maximum coordinates in x and y. The coordinates are specified inclusively, meaning that a minimum of 0 and a maximum of 9 results in ten items. Counting begins from zero. All pixels in the image must be assigned to a panel. See "A note on data orientation" in the top level README file for important information about how CrystFEL defines the axes. All coordinates (including the centre coordinates for each panel) are measured according to these axes: there is no coordinate system local to a panel. The syntax for a simple geometry might be as follows: ; The number of panels n_panels = 1 ; "0/" specifies the first (and only) panel. If we had more panels, there would ; be a copy of the following lines but prefixes with "1/", "2/" and so on. ; The region of the image which belongs to this panel: 0/min_x = 0 0/max_x = 1023 0/min_y = 512 0/max_y = 1023 ; The coordinates of the central beam which should be ; used for pixels in this panel: 0/cx = 491.9 0/cy = 440.7 ; The camera length (in metres) for this panel 0/clen = 67.8e-3 ; The resolution (in pixels per metre) for this panel 0/res = 13333.3 ; 75 micron pixel size ; The readout direction (x or y). If more than three peaks are found in ; the same readout region, they are all discarded. This helps to avoid ; problems due to streaks appearing along the readout direction. 0/badrow_direction = y See the "examples" folder for some examples.