La/B4C small period multilayer interferential mirror for the analysis of boron

This work was partly carried out at BESSY II in the framework of the project BESSY Number HPP33/150902 and supported by the European Commission under the ‘Human Potential Programme, Transnational Access to Major Research Infrastructures’, Contract No HPRI-1999-00028.; International audience; A La/B4C multilayer interferential mirror with small period d (4.8 nm) was produced by diode sputtering for the detection of the boron K emission by wavelength-dispersive x-ray spectrometry at a large Bragg angle (close to 45°). The structure of the mirror has been characterized by grazing incidence x-ray reflectometry, and its performance at the energy of the boron K emission (183 eV) was evaluated by means of polarized synchrotron radiation. A spectrometric measurement shows that the La/B4C mirror has improved the detection limit of boron using by a factor of 2 with respect to similar Mo/B4C mirrors, and by a factor of 4 with respect to a lead stearate crystal.