Dr. Julien Philippe | [from Nanjing, China]

Title: New Scientific Opportunities with next Generation Portable Large Volume High Pressure / Temperature / Stress / Tomography Cells

Time: 11:00 - 12:00 PM, Friday, November 10, 2017

Place: Conference room 410, HPSTAR (Shanghai)

Host: Ho-Kwang Mao

Abstract

In this talk, I will describe a recently developed portable large volume high-pressure / temperature / stress / tomography device installed at ESRF, DIAMOND and SOLEIL for extreme chemistry, materials and Earth sciences. Synchrotron X-ray microtomography is a non-destructive 3D imaging / microanalysis method selective to a wide range of properties such as morphology, density, chemical composition, chemical states, structure, and crystallographic perfection with extremely high sensitivity and spatial resolution.

To extend this technique to extreme conditions (high-pressure/high-temperature/high stress), I developed a new portable device, the RoToPEc [1]. In this new system, insert in a V7 type Paris-Edinburgh (PE) press modified, both anvils can rotate independently under load, with no limitation in angle, through two sets of gear reducers and thrust bearings. The accurate and simultaneous rotation of the top and bottom anvils is achieved using stepper motors and optical encoders positioned precisely on the both anvils. The ability to fully rotate the sample chamber under extreme conditions (up to 15 GPa and 2200K), overcomes the usual limited angular aperture of ordinary high pressure set-ups, allowing complete sets of tomographic projections to be acquired, in both full-field imaging or micro-diffraction modes (scanning with a pencil beam of FWHM 3 x 3 μm2 at several projection angles). Additionally, independent and controlled rotation of each anvil enables operation in shearing (one anvil rotates while the other is stationary) or deformation modes (both anvils rotate in opposite directions) under high pressure, temperature conditions.

Our portable device has been easily and successfully adapted to various multi-modal synchrotron experimental set-up at beamlines ID27 (ESRF), PSICHE (SOLEIL), and I12 (DIAMOND). The potential of this new equipment for in situ synchrotron experiments will be illustrated by preliminary results recently obtained from these facilities on many scientific cases.

To conclude, I will present the new scientific opportunities our portable device allows for studies of phase transition, synthesis, density, crystallization and deformation under extreme PT conditions.

[1] J. Philippe et al., ‘Rotating tomography Paris–Edinburgh cell: a novel portable press for micro-tomographic 4-D imaging at extreme pressure/temperature/stress conditions’, High Press. Res., vol. 36, no. 4, pp. 512–532, Oct. 2016.

Work experience

October 2004 – March 2016 IMPMC, CNRS, Paris, France

Institute of Mineralogy, Physics of Materials and Cosmochemistry Mechanical Engineer in high-pressure system

Responsibilities:

Technical design and development of high pressure devices (mainly large volume and sometimes the diamond anvil cell). In charge of maintenance, high pressure safety and technical support.

• Design high pressure mechanical system with software like Solidworks

• Selection of suitable materials which are adapt to mechanical stress, cryogenic or high

temperature, magnetic field, radioactivity environment

• Calculation with finite element software

• Control, test and validate the pressure behavior of devices

• Users’ training and technical support

• Maintenance of high pressure system

• High pressure safety advisor in the Institute

• Technical collaboration and experienced user of synchrotron (ESRF, SOLEIL, DIAMOND)

and neutron sources (ILL, PSI, ISIS, OPAL)