Low-energy contamination of Mo microsource X-ray radiation: Analysis and solution of the problem

In recent years, microsource sealed tubes in combination with multilayer optics have been adopted in many crystallography laboratories for very low power X-ray generation, monochromatization and high-brilliance microfocusing. All these factors allow high-performance experiments on a laboratory scale. However, a fundamental defect of this technology has been discovered, namely a significant contamination of the characteristic radiation by low-energy photons. Some simple experiments are reported, showing that the contamination can significantly reduce the accuracy of the measured intensities, especially when Mo K radiation is used. A simple and economic solution to the problem is proposed: an aluminium filter approximately 100 m thick, which efficiently removes the low-energy contaminant photons. © 2011 International Union of Crystallography Printed in Singapore-all rights reserved.