Design, development and applications of etched multilayers for soft X-ray spectroscopyKarine Le Guen, Rabah Benbalagh, Jean-Michel André, Jean-René Coudevylle and Philippe JonnardEur. Phys. J. Appl. Phys., 78 2 (2017) 20702DOI: https://doi.org/10.1051/epjap/2017160287