Software Engineering Processes Used to Develop the NIF Integrated Computer Control System (open access)

Software Engineering Processes Used to Develop the NIF Integrated Computer Control System

We have developed a new target platform to study Laser Plasma Interaction in ignition-relevant condition at the Omega laser facility (LLE/Rochester)[1]. By shooting an interaction beam along the axis of a gas-filled hohlraum heated by up to 17 kJ of heater beam energy, we were able to create a millimeter-scale underdense uniform plasma at electron temperatures above 3 keV. Extensive Thomson scattering measurements allowed us to benchmark our hydrodynamic simulations performed with HYDRA [1]. As a result of this effort, we can use with much confidence these simulations as input parameters for our LPI simulation code pF3d [2]. In this paper, we show that by using accurate hydrodynamic profiles and full three-dimensional simulations including a realistic modeling of the laser intensity pattern generated by various smoothing options, fluid LPI theory reproduces the SBS thresholds and absolute reflectivity values and the absence of measurable SRS. This good agreement was made possible by the recent increase in computing power routinely available for such simulations.
Date: October 3, 2007
Creator: Ludwigsen, A P; Carey, R W; Demaret, R D; Lagin, L J; Reddi, U P & Van Arsdall, P J
System: The UNT Digital Library
Target Diagnostic Instrument-Based Controls Framework for the National Ignition Facility (NIF) (open access)

Target Diagnostic Instrument-Based Controls Framework for the National Ignition Facility (NIF)

The extreme physics of targets shocked by NIF's 192-beam laser are observed by a diverse suite of diagnostics including optical backscatter, time-integrated and gated X-ray sensors, and laser velocity interferometry. Diagnostics to diagnose fusion ignition implosion and neutron emissions are being planned. Many diagnostics will be developed by collaborators at other sites, but ad hoc controls could lead to unreliable and costly operations. An instrument-based controls (I-BC) framework for both hardware and software facilitates development and eases integration. Each complex diagnostic typically uses an ensemble of electronic instruments attached to sensors, digitizers, cameras, and other devices. In the I-BC architecture each instrument is interfaced to a low-cost Windows XP processor and Java application. Each instrument is aggregated with others as needed in the supervisory system to form an integrated diagnostic. The Java framework provides data management, control services and operator GUI generation. I-BCs are reusable by replication and reconfiguration for specific diagnostics in XML. Advantages include minimal application code, easy testing, and better reliability. Collaborators save costs by assembling diagnostics with existing I-BCs. This paper discusses target diagnostic instrumentation used on NIF and presents the I-BC architecture and framework.
Date: October 3, 2007
Creator: Shelton, R. T.; O'Brien, D. W.; Kamperschroer, J. H. & Nelson, J. R.
System: The UNT Digital Library
CAD Model and Visual Assisted Control System for NIF Target Area Positioners (open access)

CAD Model and Visual Assisted Control System for NIF Target Area Positioners

The National Ignition Facility (NIF) target chamber contains precision motion control systems that reach up to 6 meters into the target chamber for handling targets and diagnostics. Systems include the target positioner, an alignment sensor, and diagnostic manipulators (collectively called positioners). Target chamber shot experiments require a variety of positioner arrangements near the chamber center to be aligned to an accuracy of 10 micrometers. Positioners are some of the largest devices in NIF, and they require careful monitoring and control in 3 dimensions to prevent interferences. The Integrated Computer Control System provides efficient and flexible multi-positioner controls. This is accomplished through advanced video-control integration incorporating remote position sensing and realtime analysis of a CAD model of target chamber devices. The control system design, the method used to integrate existing mechanical CAD models, and the offline test laboratory used to verify proper operation of the control system are described.
Date: October 3, 2007
Creator: Tekle, E. A.; Wilson, E. F. & Paik, T. S.
System: The UNT Digital Library
NIF ICCS Test Controller for Automated & Manual Testing (open access)

NIF ICCS Test Controller for Automated & Manual Testing

The National Ignition Facility (NIF) Integrated Computer Control System (ICCS) is a large (1.5 MSLOC), hierarchical, distributed system that controls all aspects of the NIF laser [1]. The ICCS team delivers software updates to the NIF facility throughout the year to support shot operations and commissioning activities. In 2006, there were 48 releases of ICCS: 29 full releases, 19 patches. To ensure the quality of each delivery, thousands of manual and automated tests are performed using the ICCS Test Controller test infrastructure. The TestController system provides test inventory management, test planning, automated test execution and manual test logging, release testing summaries and test results search, all through a web browser interface. Automated tests include command line based frameworks server tests and Graphical User Interface (GUI) based Java tests. Manual tests are presented as a checklist-style web form to be completed by the tester. The results of all tests, automated and manual, are kept in a common repository that provides data to dynamic status reports. As part of the 3-stage ICCS release testing strategy, the TestController system helps plan, evaluate and track the readiness of each release to the NIF facility.
Date: October 3, 2007
Creator: Zielinski, J S
System: The UNT Digital Library
Electron Cooling and Electron-Ion Colliders at Bnl. (open access)

Electron Cooling and Electron-Ion Colliders at Bnl.

Superconducting Energy Recovery Linacs (ERL) have significant potential uses in various fields, including High Energy Physics and Nuclear Physics. Brookhaven National Laboratory (BNL) is pursuing some of the potential applications in this area and the technology issues that are associated with these applications. The work addressed in this paper is carried out at BNL towards applications in electron cooling of high-energy hadron beams and electron-nucleon colliders. The common issues for these applications are the generation of high currents of polarized or high-brightness unpolarized electrons, high-charge per bunch and high-current. One must address the associated issue of High-Order Modes generation and damping. Superconducting ERLs have great advantages for these applications as will be outlined in the text.
Date: October 3, 2007
Creator: Ben-Zvi, Ilan
System: The UNT Digital Library
Computational s-Block Thermochemistry with the Correlation Consistent Composite Approach (open access)

Computational s-Block Thermochemistry with the Correlation Consistent Composite Approach

Article discussing research on computational s-block thermochemistry with the correlation consistent composite approach, which has been shown to accurately compute gas-phase enthalapies of formation for alkali and alkaline earth metal oxides and hydroxides.
Date: October 3, 2007
Creator: DeYonker, Nathan J.; Ho, Dustin S.; Wilson, Angela K. & Cundari, Thomas R., 1964-
System: The UNT Digital Library
Benchmarking the Stack Trace Analysis Tool for BlueGene/L (open access)

Benchmarking the Stack Trace Analysis Tool for BlueGene/L

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Date: October 3, 2007
Creator: Lee, G L; Ahn, D H; Arnold, D C; de Supinski, B R; Miller, B P & Schulz, M W
System: The UNT Digital Library