This is a dictionary of field names to use for describing a capillary as used in X-ray beamlines. Based on information provided by Gerd Wellenreuther. Type of the capillary The manufacturer of the capillary. This is actually important as it may have an impact on performance. The gain of the capillary as a function of energy The transmission of the capillary as a function of energy The focal size in FWHM