Robert W. Carey

The national ignition facility: early operational experience with a large Ada control system

The National Ignition Facility (NIF) currently under construction at the University of California Lawrence Livermore National Laboratory (LLNL) is a 192-beam, 1.8-Megajoule, 500-Terawatt laser being built by the Department of Energy and the National Nuclear Security Agency (NNSA) for inertial confinement fusion and high-energy-density experimental studies. The stadium-sized facility is currently activating systems for first light and will be completed in 2008.The facility is controlled by the Integrated Computer Control System (ICCS), a layered architecture of 300 front-end processors (FEP) coordinated by supervisor subsystems. The FEPs are distributed computers that interface to physical devices through VME-bus and PCI-bus crates. The functional subsystems - beam control including automatic beam alignment and wavefront correction, laser pulse generation and pre-amplification, diagnostics, pulse power, and shot timing - implement the actions of operators at eight graphic consoles, coordinate control, and display and archive data in a database. The software architecture mimics the hardware design levels: software devices in FEPs model hardware control points and supervisory objects model the line replaceable units that modularize the laser system. Graphic user interfaces are provided to make status and control of each level accessible to operators.The ICCS software is based on an object-oriented framework that incorporates services for archiving, machine configuration, graphical user interface, status monitoring, event logging, scripting, alert management, and access control. Software code development uses a mixed language environment of Ada (for functional controls) and Java (for user interface and database backend). CORBA is used to communicate between languages and processors. Substantial benefits credited to using Ada include the formality of controlled interfaces that rely on Adas type model, easy-to-construct exception processing and the robustness of Adas tasks.A strategy of incremental cycles of construction and formal test has been used since project inception. The project has completed more than 30 planned cycles of deployment into testbeds and is now integrating with the first 4 operational beamlines in the facility. Fifty of the planned 300 FEPs have been installed and tested with facility equipment. These implement nearly 200 classes that model physical control hardware - some 2500 software objects. Nearly all of the top-level functional subsystems, embodying some 110 application classes, have been commissioned in the facility. The integrated control system has successfully executed shots into test diagnostics in support of laser integration. The first coordinated facility shots to the 10-m diameter target chamber are expected in early 2003.Issues of robustness and scaling arise as the system integrates larger ensembles of control points and serves an increasing number of operators. The system comprises some 60 intercommunicating processes, and since none of these are known to be defect free, techniques for replacement and restart of individual processes are required. The most common communication pattern - publish and subscribe - is supported by a connection management framework that adds exception handlers to the ORB in order to restore broken connections and restart failed processes without explicit action by application client codes.This work was performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under Contract No. W-7405-Eng-48.

Status of the National Ignition Facility integrated computer control system

The National Ignition Facility (NIF), currently under construction at the Lawrence Livermore National Laboratory, is a stadium-sized facility containing a 192-beam, 1.8-megajoule, 500-terawatt, ultraviolet laser system together with a 10-meter diameter target chamber with room for nearly 100 experimental diagnostics. When completed, NIF will be the worlds largest and most energetic laser experimental system, providing an international center to study inertial confinement fusion and the physics of matter at extreme energy densities and pressures. NIFs 192 energetic laser beams will compress fusion targets to conditions required for thermonuclear burn, liberating more energy than required to initiate the fusion reactions. Laser hardware is modularized into line replaceable units such as deformable mirrors, amplifiers, and multi-function sensor packages that are operated by the integrated computer control system (ICCS). ICCS is a layered architecture of 300 front-end processors attached to nearly 60,000 control points and coordinated by supervisor subsystems in the main control room. The functional subsystems beam control including automatic beam alignment and wavefront correction, laser pulse generation and pre-amplification, diagnostics, pulse power, and timing-implement automated shot control, archive data, and support the actions of fourteen operators at graphic consoles. Object-oriented software development uses a mixed language environment of Ada (for functional controls) and Java (for user interface and database backend). The ICCS distributed software framework uses CORBA to communicate between languages and processors. ICCS software is approximately 3/4 complete with over 750 thousand source lines of code having undergone off-line verification tests and deployed to the facility. NIF has entered the first phases of its laser commissioning program. NIF has now demonstrated the highest energy 1/spl omega/, 2/spl omega/, and 3/spl omega/ beamlines in the world. NIFs target experimental systems are also being installed in preparation for experiments to begin in late 2003. This talk will provide a detailed look at the status of the control system.