Measurement Capabilities
State-of-the-art X-ray and optical diagnostics are available at the DCS to enable time-resolved, in-situ, atomic-scale investigations of condensed matter phenomena under dynamic compression.
Diffraction/Scattering Detectors
Time-resolved X-ray diffraction (XRD) measurements provide atomic-scale changes during dynamic compression and deformation. Phenomena that can be examined include structural transformations, texture evolution, deformation induced anisotropic strains, and evolution of microstructural heterogeneities.
- Four-frame indirect (phosphor-based) XRD detectors are capable of recording 250-ps-duration X-ray images every 77 ns, matching the X-ray period of the 48-bunch mode. Active area diameters are 75 mm, 120 mm, and 150 mm. Our detectors have high DQE for X-ray energies to 70+ keV.)
- Powder diffraction measurements are obtained using a pink X-ray beam with energies extending to 70+ keV and X-ray spectral bandwidths of a few percent. Broadband X-rays are also available for Laue diffraction measurements on single crystals.
Imaging Detectors
Time-resolved, high-spatial-resolution (~5 µm), phase contrast imaging (PCI) or absorption radiography measurements are used to observe the evolution of micro- and meso-scale changes during dynamic loading. The scintillator-based, 16-frame indirect-detection system is optimized for 48-bunch mode and capable of recording 16 frames frames per experiment every 77 ns.
- LYSO:Ce scintillator with 2.5X, 5X or 10X microscope objective and eight dual-frame ICCDs
- Field-of-View: from (1.25 mm)^2 up to the white beam size (See white beam sizes on the Available X-Ray Beam Spot Sizes table on the X-Ray Beam Modes and Properties page)
Optical Diagnostics for Time-Resolved Continuum Measurements
Simulatenous time-resolved laser velocimetry (e.g., VISAR and PDV) measurements are available to provide continuum data that complement the X-ray diffraction and/or imaging measurements.
Particle velocity measurements in the impact facilities are obtained via fiber coupled VISAR and PDV systems located in the DCS Instrumentation Room. The custom-made interferometers are highly versatile, offering multiple Velocity-Per-Fringe (VPF) capabilities for the VISAR systems and continuous PDV upshifting capability. Each interferometer includes gated and CW laser sources, high speed and high gain detectors, multiple high-speed digitizers, and multiple fiber optic lines to each end station.
The primary optical diagnostics in the laser-shock facility is a line-VISAR system. The line-VISAR incorporates dual-VPF measurements, and each axis can be rotated independently and continuously to any orientation. It is possible to obtain spatially resolved velocity profiles with ~10 µm resolution. Fiber coupled point VISAR and PDV measurements are also available in the laser-shock facility.
The following optical diagnostics are available at the DCS:
PDV System
Impact Facilities
• 8 Channels with upshifting capability
• 5 W laser (1550 nm wavelength
•Continuous ±5 GHz reference beam frequency shift
•12.5 GHz bandwidth detector/oscilloscope
Visar System
Impact Facilities
• 8 fixed VPF Push-Pull Point VISARs
• Available VPFs (m/s/fringe): 72, 95, 181, 308, 458, 748, 945, 1555
• Standard dual VPF measurements through return light splitting
• 18 W CW laser source (532 nm wavelength)
Laser Shock Facility
• 2-axis, dual-VPF line VISAR
• Standard recording duration: 20 or 40 ns
• Two independently rotatable axes
• 25 mJ, 200 ns, 532 nm laser source
• <200 ps synchronization to an X-ray bunch
• 8 fixed VPFs Push-Pull Point VISARs (dual-VPF)
• Can run simultaneously with the line-VISAR
Dedicated Optical Diagnostic Digitizers
Impact Facilities
• 8 digitizer channels (12.5 GHz and 10 GHz) for PDV
• 8 digitizer channels (6 GHz and 8 GHz) for VISARLaser Shock Facility
• 4 channels per each 6 GHz, 8 GHz, and 12.5 GHz digitizer (12 channels total)
• 4 digitizer channels (12.5 GHz) for timing
