Laser Shock Facility

The laser shock facility includes a clean room to house the drive laser and a hutch containing a specialized target chamber that features a multi-sample target holder with motorized position control, large ports for diagnostics access, and motorized optics for precise positioning of the drive laser focal spot. X-ray diffraction “snapshots” of targets under dynamic compression are measured using single X-ray pulses that are isolated by a high-speed X-ray chopper. The drive laser and diagnostics are synchronized to the storage ring RF clock to ensure precise relative timing of the X-ray pulses, drive laser, and diagnostic measurements.

Descriptors of the DCS laser shock capabilities are documented within these publication:

• Wang, X., P. Rigg, J. Sethian, N. Sinclair, N. Weir, B. Williams, J. Zhang, J. Hawreliak, Y. Toyoda, Y. M. Gupta, Y. Li, D. Broege, J. Bromage, R. Earley, D. Guy, and J. Zuegel (2019). “The Laser Shock Station in the Dynamic Compression Sector. I.” Review of Scientific Instruments 90: 053901-1-053901-16.
• Broege, D., S. Fochs, G. Brent, J. Bromage, C. Dorrer, R. F. Earley, M. J. Guardalben, J. A. Marozas, R. G. Roides, J. Sethian, X. Wang, D. Weiner, J. Zweiback, and J. D. Zuegel (2019). “The Dynamic Compression Sector Laser: A 100-J UV Laser for Dynamic compression Research.” Review of Scientific Instruments 90: 053001-1-053001-10.

Laser shock experiments offer the following specifications:

Driver Laser

• 100 J laser system delivering up to 100 J on target
• 351 nm fixed wavelength on target
• Smooth focal spots: Focused on target to a super-Gaussian “flat-top” spatial profile – select from a 250, 350, 500, 750 or 1 mm diameter
• Flexible pulse shape control with 5-15 ns pulse duration
  • DCS offers 11 standard pulse shapes each run. Ten of these are aimed at maintaining a constant stress in a Kapton ablator with varying amplitude and duration, and one is a 15 ns ramped pulse shape (13 ns ramp and 2 ns hold).
  • Other UV pulse shapes may be requested by users with a lead time of 2 months. As a guide for the initial design, the integrated UV pulse energy will be approximately 100 J, but it will be lower for pulses with a large dynamic range.

• High throughput – one shot every 25 minutes (20+ shots per day)
• Beam smoothing of better than 8%
• Shock/Ramp compression with high reproductivity
• Tunable UV laser pulse energy on target: 30-100% of full UV pulse energy. Ten percent increments may be selected using beamsplitters with no distortion of the UV laser pulse shape, and finer granularity is available through infrared (IR) attenuation within the laser, which requires modification of the IR pulse to achieve the same UV shape.

Target Chamber and Velocimetry

• Highly flexible target chamber with translation stage and 135° rotation to vary angle between x-ray and laser beams
  • Chamber motion: X-Y 100mm (±10 µm) and Rotation 135° (±0.001°)
  • Sample Motion, 3-axis translation (±5 µm) and 2-axis rotation
• Multiple ports for simultaneous diagnostics
• LineVISAR and/or point VISAR diagnostic capabilities for each experiment
• Target holder for up to 22 targets

Personnel Requirements:

• Please refer to the User Guidelines and Required Training Information within the User Actions Timeline
  

Target Requirements:

• Laser Sample Fabrication Instructions
• Configuration Diagram