X-RAY ABSOLUTE INTENSITY MEASUREMENT AT HASYLAB ULTRASMALL ANGLE X-RAY-SCATTERING BEAMLINE BW4

In order to obtain small angle scattering intensities in absolute unit s, measurements of the incident beam intensity and the intensity trans mitted through the sample are required. For this purpose the scatterin g intensity of a calibrated polyethylene (LUPOLEN) standard is used. F or the determination of the absolute photon flux and the correction of the scattering patterns obtained with a two dimensional position sens itive detector we use the detector response function. A set of data me asured subsequently at the standard and at a given sample can be evalu ated in a program that calculates a pattern in absolute units correcte d by means of the detector response. This program also calculates the absolute photon flux, determines automatically the center coordinates of the incident beam, and calculates the scattering vectors that belon g to the different positions on the detector. (C) 1997 American Instit ute of Physics. [S0034-6748(97)02111-4].