  Melting experiments require rapid data acquisition due to instabilities of
the molten sample and optical drifting due to the high required laser power. In
this work, the melting curve of zirconium has been determined for the first
time up to 80 GPa and 4000 K using in-situ fast x-ray diffraction (XRD) in a
laser-heated diamond anvil cell (LH-DAC). The main method used for melt
detection was the direct observance of liquid diffuse scattering (LDS) in the
XRD patterns and it has been proven to be a reliable melting diagnostic. The
effectiveness of other melting criteria such as the appearance temperature
plateaus with increasing laser power is also discussed.
