Laser and Target Area System Developed for the Dynamic Compression Sector

October 2016

CAD model of the target chamber in which
the laser and x-ray beams will intersect the target.

The University of Rochester's Laboratory for Laser Energetics (LLE) developed a 100-J UV laser and target area system for the Dynamic Compression Sector (DCS) at the Advanced Photon Source (APS) located at the Argonne National Laboratory near Chicago. This new research facility is operated by Washington State University (WSU) under sponsorship from the National Nuclear Security Administration (NNSA). LLE partnered with Logos Technologies to develop and build the high-energy laser, which is suitable for a broad range of applications. The APS is a state-of-the-art user facility dedicated to dynamic compression science, a field that researches materials under extreme conditions (large compressions, high temperatures, and large deformations).

The DCS Laser System developed by LLE will drive shocks in condensed matter that will be probed by picosecond x-ray pulses from the synchrotron source. The laser

  • provides flexible temporal pulse shaping, which produces laser pulses with nominal
    5- to 15-ns pulse widths;
  • employs smoothing by spectral dispersion (SSD) to produce smooth, flattop spatial profiles on target;
  • measures the on-target spot shape for every shot; and
  • operates at one shot every 20 min.

The DCS laser is a compact design that fits in a 30-ft × 10-ft clean room next to the shielded experimental hutch.

Newly developed control system software, introduced by Logos Technologies, makes this laser easier to operate than other systems of this scale and function. This software allows a single operator to align and fire the laser. It can also be used with other laser systems, which makes it possible to support a broad range of research and use.

A novel target area system designed by LLE includes a target chamber, target positioner, and optical train to deliver the laser. In addition to the port used to deliver the laser beam, the target chamber includes 15 large ports for target diagnostics and auxiliary systems and smaller ports for the Target Viewing System. The target chamber translates horizontally and vertically to align the target with various APS x-ray beam positions. The chamber also rotates through 135° to change the laser angle of incidence with respect to the x-ray beam; this supports a range of different experimental configurations. The laser beam path in the target area is an extension of the laser clean room envelope. LLE has implemented an existing OMEGA target position design with a target holder capable of holding up to 24 targets. These targets can be step indexed without breaking the target chamber vacuum. Delivery of the DCS target area system will take place in early 2017 at which time the DCS will be available to national and international scientific users.

Other scientific collaborators in the DCS research activities include the U.S. Department of Energy National Nuclear Safety Administration, several academic institutions, national laboratories (Lawrence Livermore, Los Alamos, and Sandia) and the Department of Defense laboratories, including both the Army Research and Naval Research Laboratories.

Photograph of the laser at LLE, taken before it was disassembled for shipping to APS.