http://portal.nersc.gov/archive/home/projects/cxidb/www/83/agipd-calib-v1/kuhnm/dark/r0266-r0267-r0268/dark_joined_constants_agipd.h5
http://portal.nersc.gov/archive/home/projects/cxidb/www/83/agipd-calib-v1/kuhnm/dark/r0266-r0267-r0268/dark_joined_constants_xfel.h5