  We present the development, manufacturing and performance of spherically bent
crystal analyzers (SBCAs) of 100 mm diameter and 0.5 m bending radius. The
elastic strain in the crystal wafer is partially released by a "strip-bent"
method where the crystal wafer is cut in strips prior to the bending and the
anodic bonding process. Compared to standard 1 m SBCAs, a gain in intensity is
obtained without loss of energy resolution. The gain ranges between 2.5 and
4.5, depending on the experimental conditions and the width of the emission
line measured. This reduces the acquisition times required to perform high
energy-resolution x-ray absorption and emission spectroscopy on ultra-dilute
species, accessing concentrations of the element of interest down to, or below,
the ppm (ng/mg) level.
