pre-workshop questions 1. What are our immediate needs for an ALS laser heating system? 2. What are our future ideals for an ALS laser heating system? 3. What are key technical issues we would like to see addressed? 4. What experiments can address these issues?

laser heating meeting at the ALS we met Dec 4th at ALS to (a) review our science goals and related technical needs (b) evaluate current status and to provide recommendations designed to plot a course from (a) to (b)

science goals “phase stability studies for all sorts of Earth Materials” “phase stability studies for assemblages of lower mantle phases” “multiprobes, including Raman and Brillouin along with XRD to determine elastic properties, and melting. The idea is to build multiple and independent ways of determining everything we want to know (P,T state and phases of samples; elastic properties of phases)” “laser heat fluids like water and ammonia and mixtures up to 4000K and 40 GPa” “synthesis..., new states of matter, and pulsed Raman measurements during laser heating”

technical needs “ultra-stable (non-wandering, non-jittery) laser spot that is focused on the ultra-stable hotspot” “control the size of the beam...both X-ray and laser spot” tight focus and lots of available power from the laser “stable, two-sided laser heating combined with external heating External heating range needs to overlap the laser heating T range” “real-time determinations of three-dimensional temperature distributions” “more independent and reliable criteria for determining melting inside the laser heated dac” “independent control of the x-ray beam position” relative to the hotspot position”

recommendations 1. There needs to be a person who will midwife the ALS laser heating system 2. Provide a detailed design report which especially addresses issues of mechanical and temporal stability: 3. Ultra stable (no spatial wandering or power fluctuations) laser spot that is focussed on an ultra-stable X-ray diffraction spot within the sample. 4. Establish resistance heating along with laser heating 5. Make use of the user community to help with installation, testing, and preliminary experiments

accomplishments Double sided laser heating system is built and will be installed on the X-ray line August 2004 user community input: dave walker--resistance heating user community input: Abby Kavner--measure temperature gradient garnet P,T eqns. of state anisotropic thermal diffusivity of graphite