WL&agr;radiation filtered through a Cu&sngbnd;Zn foil is essentially monochromatic and has the advantage over filtered CuK&agr;or MoK&agr;radiation in that theWL&agr;1line is approximately ten times as intense as theWL&agr;2line. Moreover the comparatively wide &Dgr;&lgr;‐spread (WL&agr;2−WL&agr;1) results in very sharp powder lines at those Bragg angles where the CuK&agr;doublet or MoK&agr;doublet is unresolved.