LLNL, Livermore, California, USA
The Advanced Radiographic Capability (ARC) currently under development for the National Ignition Facility (NIF) will provide short (1-50 picoseconds) ultra high power (>1 Petawatt) laser pulses used for a variety of diagnostic purposes on NIF ranging from a high energy x-ray pulse source for backlighter imaging to an experimental platform for fast-ignition. A single NIF Quad (4 beams) is being upgraded to support experimentally driven, autonomous operations using either ARC or existing NIF pulses. Using its own seed oscillator, ARC generates short, wide bandwidth pulses that propagate down the existing NIF beamlines for amplification before being redirected through large aperture gratings that perform chirped pulse compression, generating a series of high-intensity pulses within the target chamber. This significant effort to integrate the ARC adds 40% additional control points to the existing NIF Quad and will be deployed in several phases over the coming year. This talk discusses some new unique ARC software controls used for short pulse operation on NIF and integration techniques being used to expedite deployment of this new diagnostic.
LLNL, Livermore, California, USA
The programmable spatial shaper (PSS) within the National Ignition Facility (NIF) reduces energy on isolated optic flaws in order to lower the optics maintenance costs. This will be accomplished by using a closed-loop system for determining the optimal liquid-crystal-based spatial light pattern for beamshaping and placement of variable transmission blockers. A stand-alone prototype was developed and successfully run in a lab environment as well as on a single quad of NIF lasers following a temporary hardware reconfiguration required to support the test. Several challenges exist in directly integrating the C-based PSS engine written by an independent team into the Integrated Computer Control System (ICCS) for proof on concept on all 48 NIF laser quads. ICCS is a large-scale data-driven distributed control system written primarily in Java using CORBA to interact with +60K control points. The project plan and software design needed to specifically address the engine interface specification, configuration management, reversion plan for the existing 0% transmission blocker capability, and a multi-phase integration and demonstration schedule.
LLNL, Livermore, California, USA
The National Ignition Facility (NIF) is operated by the Integrated Computer Control System in an object-oriented, CORBA-based system distributed among over 1800 front-end processors, embedded controllers and supervisory servers. At present, NIF operates 24x7 and conducts a variety of fusion, high energy density and basic science experiments. During the past year, the control system was expanded to include a variety of new diagnostic systems, and programmable laser beam shaping and parallel shot automation for more efficient shot operations. The system is also currently being expanded with an Advanced Radiographic Capability, which will provide short (<10 picoseconds) ultra-high power (>1 Petawatt) laser pulses that will be used for a variety of diagnostic and experimental capabilities. Additional tools have been developed to support experimental planning, experimental setup, facility configuration and post shot analysis, using open-source software, commercial workflow tools, database and messaging technologies. This talk discusses the current status of the control and information systems to support a wide variety of experiments being conducted on NIF including ignition experiments.
LLNL, Livermore, California, USA
Network packet inspection using port mirroring provides the ultimate tool for understanding complex behaviors in large distributed control systems. The timestamped captures of network packets embody the full spectrum of protocol layers and uncover intricate and surprising interactions. No other tool is capable of penetrating through the layers of software and hardware abstractions to allow the researcher to analyze an integrated system composed of various operating systems, closed-source embedded controllers, software libraries and middleware. Being completely passive, the packet inspection does not modify the timings or behaviors. The completeness and fine resolution of the network captures present an analysis challenge, due to huge data volumes and difficulty of determining what constitutes the signal and noise in each situation. We discuss the development of a deep packet inspection toolchain and application of the R language for data mining and visualization. We present case studies demonstrating off-normal analysis in a distributed real-time control system. In each case, the toolkit pinpointed the problem root cause which had escaped traditional software debugging techniques.
LLNL, Livermore, California, USA
For many experiments planned on the National Ignition Facility (NIF), high-energy x-ray backlighters are an important diagnostic. NIF will be deploying this year a new Advanced Radiographic Capability (ARC) for generating these high-energy short-pulses. The precision of the Automatic Alignment (AA) for ARC is an important element in the success of the enhancement. A key aspect of the ARC AA is integration of the new alignment capabilities without disturbing the existing AA operations of NIF. Small pointing tolerances of 5 micron precision to a 10 micron target are required. After main amplification the beams are shortened by up to 1,000x in time in the ARC compressor vessel and aimed at backlighter targets in the NIF target chamber. Alignment Stability and Verification of the compressor gratings is critical to ensuring the ARC pulses meet their experimental specifications.