LLE Annual Report
The fiscal year ending September 2012 (FY12) concluded the fifth year of the third five-year renewal of Cooperative Agreement DE-FC52-08NA28302 with the U.S. Department of Energy (DOE). This annual report serves as the final report for the Agreement and summarizes progress in inertial fusion research at the Laboratory for Laser Energetics (LLE) during the past fiscal year including work on the National Ignition Campaign (NIC). It also reports on LLE's progress on laboratory basic science research; laser, optical materials, and advanced technology development; operation of OMEGA and OMEGA EP for the NIC and high-energy-density (HED) campaigns, the National Laser Users' Facility (NLUF), and other external users; and programs focusing on the education of high school, undergraduate, and graduate students during the year.
Progress in Inertial Confinement Fusion (ICF) Research
One of LLE's principal missions is to conduct research in inertial confinement fusion (ICF) with particular emphasis on supporting the goal of achieving ignition at the National Ignition Facility (NIF). This program uses the Omega Laser Facility. During FY12, a total of 1920 target shots were taken at the Omega Laser Facility (including the 60-beam UV laser OMEGA and the four-beam, high-energy petawatt laser OMEGA EP. More than 43% of the facility's target shots in FY12 were designated as NIC experiments or experiments in support of NIC. During the last five years of the current Cooperative Agreement, 8204 target shots were taken at the Omega Laser Facility in support of the National Nuclear Security Administration (NNSA) missions. The OMEGA and OMEGA EP lasers attained average experimental effectiveness of 96.7% and 95.5%, respectively, in FY12.
LLE plays a lead role in the validation of the performance of cryogenic target implosions, essential to all forms of ICF ignition. LLE is responsible for a number of critical elements within the Integrated Experimental Teams (IET's) supporting the demonstration of indirect-drive ignition on the NIF and is the lead laboratory for the validation of the polar-drive approach to ignition on the NIF. LLE has also developed, tested, and constructed a number of diagnostics that are being used on the NIF for the NIC. During this past year, progress in the inertial fusion research program continued in three principal areas: NIC experiments and experiments in support of NIC; development of diagnostics for experiments on the NIF, OMEGA, and OMEGA EP; and theoretical analysis and design efforts aimed at improving direct-drive–ignition capsule designs (including polar-drive–ignition designs) and advanced ignition concepts such as shock ignition and fast ignition. In this volume we report in detail on these inertial fusion research efforts.
Lasers, Optical Materials, and Advanced Technology
The Laboratory's efforts in the development of advanced high-power lasers and optical materials in support of its inertial fusion and high-energy-density research programs is also covered in this volume, including: design of an ultra-intense optical parametric chirped-pulse–amplification (OPCPA) system at 910 nm and the development of a low-temperature chemical cleaning approach to remove manufacturing residue from multilayer dielectric (MLD) pulse-compressor gratings to be used in the OMEGA EP Laser System.
National Laser Users' Facility and External Users' Programs
Under the facility governance plan that was implemented in FY08 to formalize the scheduling of the Omega Laser Facility as an NNSA User Facility, Omega Facility shots are allocated by campaign. The majority (67.6%) of the FY12 target shots were allocated to the National Ignition Campaign (NIC) conducted by integrated teams from the national laboratories and LLE and to the high-energy-density campaigns conducted by teams led by scientists from the national laboratories. Nearly 29% of the facility shots in FY12 were allocated to basic science experiments. Half of these were dedicated to university basic science under the National Laser Users' Facility (NLUF) Program, and the remaining shots were allotted to the Laboratory Basic Science (LBS) Program, comprising peer-reviewed basic science experiments conducted by the national laboratories and by LLE including the Fusion Science Center (FSC). The Omega Facility is also being used for several campaigns by teams from the Commissariat á l'Énergie Atomique (CEA) of France and the Atomic Weapons Establishment (AWE) of the United Kingdom. These programs are conducted on the facility on the basis of special agreements put in place by the DOE/NNSA and the participating institutions.
During FY12 the facility users included 11 collaborative teams participating in the NLUF Program; 12 teams led by LLNL and LLE scientists participating in the LBS Program; many collaborative teams from the national laboratories conducting experiments for the NIC; investigators from LLNL and LANL conducting experiments for high-energy-density–physics programs; and scientists and engineers from CEA, AWE, and the Center for Radiative Shock Hydrodynamics (CRASH) of the University of Michigan. The work carried out on most of these programs at the Omega Facility is summarized in this report.
OMEGA Laser Facility Users Group (OLUG)
A capacity gathering of 115 researchers from over 25 universities and laboratories and 9 countries met at the Laboratory for Laser Energetics (LLE) for the Fourth Omega Laser Facility Users Group (OLUG) Workshop in April 2012. The purpose of the 2.5-day workshop was to facilitate communications and exchanges among individual Omega users and between users and the LLE management; to present ongoing and proposed research; to encourage research opportunities and collaborations that could be undertaken at the Omega Laser Facility and in a complementary fashion at other facilities [such as the National Ignition Facility (NIF) or the Laboratoire pour l'Utilisation des Lasers Intenses (LULI)]; to provide an opportunity for students, postdoctoral fellows, and young researchers to present their research in an informal setting; and to provide feedback to LLE management from the users about ways to improve the facility and future experimental campaigns. A summary report on this workshop is contained in this volume.
FY12 Omega Facility Report
During FY12, the Omega Facility conducted 1494 target shots on OMEGA and 426 target shots on OMEGA EP for a record total of 1920 target shots OMEGA averaged 11.2 target shots per operating day with availability and experimental effectiveness averages for FY12 of 94.2% and 96.7%, respectively. OMEGA EP was operated extensively in FY12 for a variety of internal and external users. A total of 356 target shots were taken into the OMEGA EP target chamber and 70 joint target shots into the OMEGA target chamber. OMEGA EP averaged 6.1 target shots per operating day with Availability and Experimental Effectiveness averages for FY12 of 88.0% and 95.5%, respectively. Highlights of achievements in FY12 are detailed in the report.
As the only major university participant in the National ICF Program, education continues to be an important mission for the Laboratory. Laboratory education programs are summarized in the report including: the high school program involving 16 students chosen from the Rochester area high schools who conduct independent research at LLE each summer; the undergraduate program which involved 42 students who participated in work or research projects at LLE this past year; and the graduate education and training program that included 74 graduate students who worked on graduate thesis research programs at LLE during the year, including 38 students pursuing a Ph.D. through the NNSA–sponsored Horton Graduate Fellowship program at LLE.
Table of Contents
- Executive Summary
- Crossed-Beam Energy Transfer in Direct-Drive Implosions
- Time-Resolved Measurements of Hot-Electron Equilibration Dynamics in High-Intensity Laser Interactions with Thin-Foil Solid Targets
- Experimental Studies of the Two-Plasmon-Decay Instability in Long-Scale-Length Plasmas
- A Front End for Ultra-Intense Optical Parametric Chirped-Pulse Amplification
- A Spherical Crystal Imager for OMEGA EP
- Amplitude Distributions of Dark Counts and Photon Counts in NbN Superconducting Single-Photon Detectors Integrated with a High-Electron Mobility Transistor Readout
- Thermal Conductivity of Solid Deuterium by the 3ω Method
- OMEGA Polar-Drive Target Designs
- Cryogenic Deuterium and Deuterium–Tritium Direct-Drive Implosions on OMEGA
- Experimental Reduction of Laser Imprinting and Rayleigh–Taylor Growth in Spherically Compressed, Medium-Z–Doped Plastic Targets
- Shell-Trajectory Measurements from Direct-Drive–Implosion Experiments
- Spherical Shock-Ignition Experiments with the 40 + 20-Beam Configuration on OMEGA
- A Single-Shot, Multiwavelength Electro-Optic Data-Acquisition System for Inertial Confinement Fusion Applications
- Shock-Ignition Experiments with Planar Targets on OMEGA
- Inelastic X-Ray Scattering from Shocked Liquid Deuterium
- Enhancement of the Laser-Induced–Damage Threshold in Multilayer Dielectric Diffraction Gratings Through Targeted Chemical Cleaning
- Magnetic-Field Generation by Rayleigh–Taylor Instability in Laser-Driven Planar Plastic Targets
- High-Resolution Spectroscopy Used to Measure Inertial Confinement Fusion Neutron Spectra on OMEGA
- Experimental Validation of the Two-Plasmon–Decay Common-Wave Process
- A Reflective Optical Transport System for Ultraviolet Thomson Scattering on OMEGA
- Laser–Plasma Interactions in Direct-Drive Ignition Plasmas
- Stress-Radiation–Induced Swelling in Plastic Capsules
- Time-Resolved Carrier Dynamics in Si-on-Glass Absorbers for Photovoltaic Cells
- Proton Emission from Cone-in-Shell Fast-Ignition Experiments at the Omega Laser Facility
- The Fourth Omega Laser Facility Users' Group Workshop
- LLE's Summer High School Research Program
- FY12 Laser Facility Report
- National Laser Users' Facility and External Users' Programs
- Publications and Conference Presentations