Upgrade of the Raman Spectroscopy System at the High-Pressure Lab of Arizona State University

Upgrade of the Raman Spectroscopy System at the High-Pressure Lab of Arizona State University Upgrade of the Raman Spectroscopy System at the High-Pressure Lab of Arizona State University Proposal Summary Overview We propose to upgrade an 18-year old Raman spectrometer at the Shim lab at Arizona State University. The upgrade also includes a motorized stage for 3D positioning of the sample for Raman phase mapping capability. The upgrade will be critical for supporting the on-going research activities and undergraduate research program in PI Shims lab. Intellectual merit Raman spectroscopy has become a standard laboratory analytical technique for diamond-anvil cell(DAC) research. Micro-beam capability combined with transparency of diamond over a wide range of electromagnetic wave makes the technique suitable for studying extremely small sample inside DAC under high pressure. PI Shim has used Raman spectroscopy extensively over the last 24 years to study a range of subjects in mineral physics, such as behaviors of lattice and OH vibrational modes in mantle silicates, modeling vibrational density of state, stability of volatile-bearing minerals, structure of amorphous phases at high pressures, high-temperature behavior of minerals, and magnetic scattering. The system has a micro beam combined with confocal setup, enabling high-quality measurements for heterogeneous samples in laser-head DAC (LHDAC) and multi-phase samples synthesized in multi-anvil press. The 2D scanning capability has played an important role in recent research projects. The system is combined with a CO2 laser heating, which makes the system even more versatile in high pressure research. The current Raman system at PI Shims lab has been constantly upgraded since it was built in 2003. The oldest parts which have never been upgraded are the CCD detector and spectrograph, which are 18-year old. Extensive use of the system over the years has introduced some mechanical issues and the detector sensitivity has degraded. Also, many key contemporary features are missing, particularly programmability and accurate mapping capability, which hampers further technical developments to meet the demand from diverse research PI Shim has been involved, such as hydrogen-rich materials in LHDAC, lower-mantle petrology in multi-anvil press, and high density target materials for laser driven shock experiments at XFEL. We request acquisition of a CCD detector, a spectrograph, and a 3D sample positioning system to support vigorous high-pressure research activity at PI Shims lab at ASU. Broader Impacts Over 18-years the Raman spectroscopy system at Shims lab has been used for training numerous postdoctoral researchers, graduate students, and undergraduate students. In particular, the Raman system has been central for PI Shims undergraduate research program at MIT and now at ASU since 2004. The activities have resulted in four papers with three undergraduate first-authored papers in peer-reviewed journals. Two female undergraduate students have so far earned Ph.D.s at Harvard and Caltech in Earth science and mechanical engineering. They were also awarded prestigious Miller fellowship from UC Berkeley for their postdocs. After moving to ASU, PI Shims undergraduate research program includes multi-anvil experiments. To support the new capability, Shim added 2D phase mapping capability to the Raman system which was moved from MIT to ASU. One of the undergraduate researchers is now in a Ph.D. program at Bayreuth University, Germany. Another undergraduate student from the training, a female student, published results based on Raman as the first author. She is admitted for the Ph.D. program in Earth science at Oxford University. Shims program has provided research opportunities to many underrepresented students, including a Black student and a Hispanic student as well as a number of female students. The upgrade we proposed here for the Raman system will provide more research opportunities to undergraduate students at ASU.