Laser-heated diamond anvil cell at the advanced light source beamline 12.2.2

The laser-heating system for the diamond anvil cell at endstation 2 of beamline 12.2.2 of the Advanced Light Source in Berkeley, CA, has been constructed and is available for in situ high-pressure high-temperature X-ray experiments. The endstation couples a high-brilliance synchrotron X-ray source with an industrial strength laser to heat and probe samples at high pressure in the diamond anvil cell. The system incorporates an 50 W Nd:YLF (cw) laser operated in TEM01* mode. Double-sided heating is achieved by splitting the laser beam into two paths that are directed through the opposing diamond anvils. X-ray transparent mirrors steer the laser beams coaxial with the X-ray beam from the superconducting bending magnet (energy range 6–35 KeV) and direct the emitted light from the heated sample into two separate spectrometers for temperature measurement by spectroradiometry. Objective lenses focus the laser beam to a size of 25 μm diameter (FWHM) in the sample region. An X-ray spot size of 10 μm diameter (FWHM) has been achieved with the installation of a pair of focusing Kirkpatrick–Baez mirrors. A unique aperture configuration has produced an X-ray beam profile that has very low intensity in the tails. The main thrust of the program is aimed at producing in situ high-pressure high-temperature X-ray diffraction data, but other modes of operation, such as X-ray imaging have been accomplished. Technical details of the experimental setup will be presented along with initial results.