Prof. Stanislav V. Sinogeikin [DAC Tools, LLC, Naperville, Illinois, USA]

Title: High / low temperature controls and time resolved experiments in diamond anvil cell -developments by HPCAT and DAC Tools

Time: 2:00 - 3:00 PM, Monday, November 12, 2018

Place: Conference room C206, HPSTAR (Beijing)

Host: Haozhe Liu

Polycom: 02120001

Abstract:

The majority of high pressure (HP) experiments at High Pressure Collaborative Access Team (HPCAT, APS) are is performed using different modifications of a versatile HP device-Diamond Anvil Cell (DAC), which allows to readily generate static pressures of hundreds of Gigapascal. While temperatures from several hundreds to several thousand degrees in DACs can be readily reached using infrared laser heating systems, lower temperatures, both elevated and cryogenic, require special devices such as resistive heaters and cryostats. Thus, over the last several years a number of sample environment control devices have been developed and implemented to expand the available temperature range from liquid helium temperatures to several hundred degrees Celsius. A considerable effort was put into developing cryogenic instrumentation for different high-pressure synchrotron techniques (powder and single crystal diffraction, inelastic scattering, etc.) We have designed and commissioned a variety of compact cryostats that can accommodate an assortment of standard and novel DACs, can be easily integrated with remote pressure control devices, and allow for high-pressure measurements at temperatures down to 2-4 K. The newest versions of compact cryostats have modular design allowing quick modifications for use with different DACs and various pressure drives (e.g. double membrane drive for accurate bidirectional pressure control, piezo drive for fast controlled rate compression/decompression, mechanical (screw) drive, etc.). The cryostats feature stable sample holder design (no sample motion during cryogenic cooling of a DAC) and flexibility to use various functional DAC attachments such as modulation coils for magnetic susceptibility measurements. The modular flexible design and abundance of electrical feed-throughs allows integration of multiple sample synthesis and analytical techniques, e.g. the sample can be synthesized at high temperature using laser heating setup with in-situ online x-ray diffraction characterization, and then magnetic susceptibility and Raman spectra can be measured after rapid cooling of the sample to cryogenic temperatures.

A significant effort was put into development of user-friendly resistive heating techniques in DACs. We focused on development of whole cell single and double stage heaters capable of reaching temperatures of 900K and beyond. The specifics of novel designs include modu ar water cooled vacuum shrouds with various window designs suitable for multiple x-ray and optical techniques (including single crystal x-ray diffraction and visible Raman spectroscopy), full integration with remotely controlled pressure drivers (e.g. single and double membrane), as well as novel heater designs. Recent advances in synchrotron sources, x-ray optics, fast area detectors, and sample environment control have enabled many time-resolved experimental techniques for studying materials at extreme pressure and temperature conditions. DAC Tools and HPCAT has made a sustained effort to develop and assemble a powerful collection of high-pressure apparatus for time resolved research and developing techniques for collecting high quality time resolved x-ray scattering data at compression rates intermediate between static and shock compression experiments. In this talk we will outline recently developed capabilities at HPCAT for synthesis of metastable and amorphous materials and studying properties (EOS, lattice relaxation, etc.) and phase transition mechanisms of materials using fast unidirectional and cyclic compression-decompression with variable strain rates up to extreme compression of tens of TPa per second.

Biography of the Speaker:

• Education

Ph.D. in Geophysics (May 1999). Geology Dept., University of Illinois at Urbana Champaign. Thesis: Elasticity of mantle minerals: composition, pressure and temperature dependence.

M.S. in Geophysics (April 1996). Geology Dept., University of Illinois at Urbana Champaign. Thesis: Elasticity of tetragonal end member majorite and solid solutions in the system Mg4Si4O12 Mg3Al2Si3O12..

Diploma (M.S.) in Petrology (June 1993). Geology Dept., Moscow State University, Russia. Thesis: The Genesis of Apatite Deposits of Khibina Massif

• Positions

July 2018 – current. Owner / manager. DAC Tools, LLC, Naperville, Illinois.

July 2013 – July 2018. Associate Director. HPCAT, Geophysical Laboratory, Carnegie Institution of Washington.

September 2010 – current. Adjunct Professor, Physics Department, University of Nevada at Las Vegas.

June 2009 – July 2018. Owner / manager. Diamond Anvil Cell Tools, Naperville, Illinois.

January 2006 – July 2013. Beamline Scientist. HPCAT, Geophysical Laboratory, Carnegie Institution of Washington.

February 2002 – January 2006. Research Scientist. Geology Dept., University of Illinois at Urbana-Champaign.

1999 - 2002. Visiting Assistant Professor / Visiting Scholar. Geology Dept., University of Illinois at Urbana-Champaign.

1994 - 1999. Graduate Student/Research Assistant/UIUC fellow. Geology Dept., University of Illinois at Urbana-Champaign.

1998 - 2005. Research Scientist. Institute of Experimental Mineralogy, Chernogolovka, Moscow dist., Russia.

1993 - 1998. Research Assistant/ Junior Research Scientist. Institute of Experimental Mineralogy, Chernogolovka, Moscow dist,. Russia.

1986 - 1993. Undergraduate/Diploma student, Geology Dept., Moscow State University, Moscow, Russia.