Dynamic Response of Materials
The state-of-the-art research facilities to investigate the dynamic response of materials are unique among academic institutions. To examine changes in condensed matter response under shock wave loading, fast, time-resolved measurements are carried out using advanced diagnostics in specialized laboratories.
- The Institute for Shock Physics (ISP) has seven launchers (gas and powder guns) for conducting impact experiments.
- Three single stage, light gas guns capable of achieving velocities up to 1.5 km/s. Gas gun capabilities include combined compression and shear loading experiments and sample recovery.
- Three powder guns capable of achieving velocities up to 2.5 km/s. One of these powder guns is used exclusively for X-Ray Diffraction (XRD) measurements.
- To achieve higher stresses (1–2 Mbar), a two stage, light gas gun is used that can reach an impact velocity of up to 5 km/s.
- With these gas and powder guns, samples can be compressed to stresses approaching 200 GPa or 2 Mbar.
Compact Pulsed Power Generator
The Compact Pulsed Power Generator (CPPG) is based on technology developed at Sandia National Laboratories (The Z Accelerator). This is one of only two such facilities currently operating in the United States.
Shockless, high pressure loading is used to determine the sample response. The data are obtained in a single experiment, versus multiple experiments with traditional methods. In addition, the dynamic response of two to four materials can be obtained in a single experiment.
The CPPG permits peak pressures to 15-20 GPa; “large” samples (~cm); risetime (~500 ns); and 2 shots/day with 4 samples/shot.
Laser Shock Laboratory
The Laser-Shock Laboratory uses a laser-driver to launch mini flyer plates to impact samples at pre-determined velocities (up to 1.5 km/s). This table top capability is convenient for small samples, energetic materials, and for rapid screening. The Laser Shock Laboratory is an excellent complement to the gas guns because pulse durations are significantly shorter than those typically attainable with gas guns.
Experimental capabilities / diagnostics:
- Ability to launch arbitrary shaped flyers to minimize edge rarefaction wave interactions
- Sample recovery
- Optical spectroscopy
Time-resolved Continuum Measurements
These measurements are used to observe the evolution of propagating shock waves. Representative equipment includes laser interferometery (VISAR), EMV gauges, piezoelectric stress gauges, and piezoresistance stress gauges.
High Speed Imaging
A high speed framing camera, with inter-frame times in nanoseconds, is used to directly image changes in a material over length scales down to the mesoscale (tens of microns).
X-Ray Diffraction Measurements (ns resolution)
X-Ray Diffraction provides information about crystal lattice structure.
Fast Optical Spectroscopy
- Absorption, Emission, and Reflection Spectroscopies provide information about the electronic states of condensed matter.
- Vibrational (Raman) Spectroscopy provides information about vibrational states.