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| ROAA01 |
Status of the ITER CODAC Conceptual Design
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481 |
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- J. W. Farthing
UKAEA Culham, Culham, Abingdon, Oxon
- M. Greenwald
MIT/PSFC, Cambridge, Massachusetts
- I. Yonekawa
JAEA/NAKA, Ibaraki-ken
- J. B. Lister
ITER, St Paul lez Durance
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Since the last ICALEPCS conference, a number of issues have been studied in the conceptual design of the ITER Control, Data Access, and Communication Systems. Almost all of the technical challenges have seen workable approaches selected. The conceptual design will be reviewed in 2007, before starting the preliminary engineering design. One software component that does not have a clear solution is the execution of data-driven schedules to operate the installation at multiple levels, from daily program management to plasma feedback control. Recent developments in workflow products might be useful. The present conceptual weakness is not having found a satisfactory "universal" description of the I&C design process for the "self-description" of the 100 procured Plant Systems. A vital CODAC design feature is to operate the full plant on the basis of imported “self-description” data, which necessarily includes the process description in each Plant System. The targeted formal link between 3-D design, process design, and process control has not yet been created. Some of the strawman designs meeting the technical requirements will be mentioned in detail.
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Slides
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| ROAA02 |
Automatic Alignment System for the National Ignition Facility
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486 |
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- A. A.S. Awwal, S. W. Ferguson, B. Horowitz, V. J. Miller Kamm, C. A. Reynolds, K. C. Wilhelmsen
LLNL, Livermore
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The Automatic Alignment System for the National Ignition Facility (NIF) is a large-scale parallel system that directs all 192 laser beams along the 300-m optical path to a 50-micron focus at target chamber in less than 30 minutes. The system commands 9,000 stepping motors to adjust mirrors and other optics. Twenty-two control loops per beamline request image processing services from a dedicated Linux cluster running Interactive Data Language tools that analyze high-resolution images of the beam and references. Process leveling assures the computational load is evenly spread. Algorithms also estimate measurement accuracy and reject off-normal images. One challenge to rapid alignment of beams in parallel is efficient coordination of shared devices, such as sensors that monitor multiple beams. Contention for shared resources is managed by the Component Mediation System, which precludes deadlocks and optimizes device motions using a hierarchical component structure. A reservation service provided by the software framework prevents interference from competing automated controls or the actions of system operators. The design, architecture and performance of the system will be discussed.
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Slides
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| ROAA03 |
Injection, Ramping and Extraction Timing for the Duke Booster
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491 |
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- G. Y. Kurkin
BINP SB RAS, Novosibirsk
- S. F. Mikhailov, V. Popov, Y. K. Wu, S. M. Hartman
FEL/Duke University, Durham, North Carolina
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A booster synchrotron capable of ramping from 0.25 to 1.2 GeV was recently commissioned at Duke University as part of the High Intensity Gamma Source upgrade. The triggering and timing system uses a combination of software logic and triggers, digital delay generators, and hardware synchronizers to coordinate the linac injector, booster synchrotron and electron storage ring. The injection system has been commissioned with a short pulse photo-injector linac into a single booster RF bucket and to two booster buckets separated by about half the circumference. It has also been commissioned with a long electron pulse from the injection linac into all 19 buckets. The extraction system, combined with short pulse kickers, can extract any of the booster's 19 electron bunches in to any of the storage ring's 64 bunches. Ramping is controlled by programmable VME based waveform generators triggered from the timing system. The system offers flexibility for commissioning and operations and provides a simple interface to the operator.
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Slides
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| ROAA04 |
XAL Online Model Enhancements for J-PARC Commissioning and Operation
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494 |
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- H. Ikeda
Visual Information Center, Inc., Ibaraki-ken
- M. Ikegami
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
- T. Ohkawa, H. Sako, G. B. Shen
JAEA, Ibaraki-ken
- A. Ueno
JAEA/LINAC, Ibaraki-ken
- C. K. Allen
LANL, Los Alamos, New Mexico
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The XAL application development environment has been installed as a part of the control system for the Japan Proton Accelerator Research Complex (J-PARC) in Tokai, Japan. XAL was initially developed at SNS and has been described at length in previous conference proceedings (e.g., Chu et. al. APAC07, Galambos et. al. PAC05, etc.). We outline the upgrades and enhancements to the XAL online model necessary for accurate simulation of the J-PARC linac. For example, we have added permanent magnet quadrupoles and additional space charge capabilities such as off-centered and rotated beams and bending magnets with space charge. In addition significant architectural refactoring was performed in order to incorporate the current, and past, upgrades into a robust framework capable of supporting future control operations. The architecture and design of XAL is as important as its function, as such, we also focus upon the revised architecture and how it supports a component-based, software engineering approach.
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Slides
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| ROAA05 |
An Approach to Stabilizing Large Telescopes for Stellar Interferometry
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497 |
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- J. Sahlmann, A. Wallander, N. Di Lieto
ESO, Garching bei Muenchen
- G. Vasisht
Jet Propulsion Laboratory, Pasadena, California
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In stellar interferometry fringe-tracking is a method of stabilizing the Optical Pathlength Difference (OPD) from the observed astronomical source to the instrument detector via different telescopes in an interferometric array. At the ESO VLT Interferometer, which includes four 8.2 m class Unit Telescopes (UTs), stabilization to better than a tenth of the observing wavelength is required in order to improve the quality and sensitivity of fringe measurements on the interferometer's scientific instruments. Unfortunately, fast mechanical vibrations due to myriad sources in the observatory infrastructure couple to UT support structure and propagate to the large telescope mirrors. The mirror motions are fast and large (typically about a wavelength) and must be compensated for in real time. We have implemented a scheme to measure the accelerations imparted to the primary, secondary, and tertiary mirrors of the UTs via a grid of suitably placed accelerometers. The measured accelerations, coupled with a simple geometric model, are converted to optical pathlengths and canceled by a wideband feed-forward compensation to a downstream optical delay line.
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