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Error Analysis of Acceleration Control Loops of a Synchrotron

Description: For beam control during acceleration, it is conventional to derive the frequency from an external reference, be it a field marker or an external oscillator, to provide phase and radius feedback loops to ensure the phase stability, radial position and emittance integrity of the beam. The open and closed loop behaviors of both feedback control and their response under the possible frequency, phase and radius errors are derived from fundamental principles and equations. The stability of the loops … more
Date: January 1, 1991
Creator: Zhang, S. Y. & Weng, W. T.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Stabilization of the axisymmetric instability in the PDX tokamak

Description: Passive stabilization, associated with the mutual inductances of the field shaping coils with the plasma and with each other, can stabilize the axisymmetric magnetohydrodynamic instability in the Princeton Poloidal Divertor Experiment device that was observed in earlier numerical studies.
Date: December 1, 1977
Creator: Jardin, S. C.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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A novel charge sensitive preamplifier without the feedback resistor

Description: A novel charge sensitive preamplifier which has no resistor in parallel with the feedback capacitor is presented. No external device or circuit is required to discharge the feedback capacitor. The detector leakage and signal current flows away through the gate of the first JFET which works with its gate to source junction slightly forward biased. The DC stabilization of the preamplifier is accomplished by an additional feedback loop, which permits to equalize the current flowing through the for… more
Date: January 1, 1992
Creator: Bertuccio, G. (Politecnico di Milano, Milan (Italy). Dipt. di Elettronica e Informazione); Rehak, P. & Xi, D. (Brookhaven National Lab., Upton, NY (United States))
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Partner: UNT Libraries Government Documents Department
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Resistive instabilities in tokamaks

Description: Low-m tearing modes constitute the dominant instability problem in present-day tokamaks. In this lecture, the stability criteria for representative current profiles with q(0)-values slightly less than unit are reviewed; ''sawtooth'' reconnection to q(0)-values just at, or slightly exceeding, unity is generally destabilizing to the m = 2, n = 1 and m = 3, n = 2 modes, and severely limits the range of stable profile shapes. Feedback stabilization of m greater than or equal to 2 modes by rf heatin… more
Date: October 1, 1985
Creator: Rutherford, P.H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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A comparison of three self-tuning control algorithms developed for the Bristol-Babcock controller

Description: A brief overview of adaptive control methods relating to the design of self-tuning proportional-integral-derivative (PID) controllers is given. The methods discussed include gain scheduling, self-tuning, auto-tuning, and model-reference adaptive control systems. Several process identification and parameter adjustment methods are discussed. Characteristics of the two most common types of self-tuning controllers implemented by industry (i.e., pattern recognition and process identification) are su… more
Date: April 1, 1992
Creator: Tapp, P.A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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TFTR initial operations

Description: The Tokamak Fusion Test Reactor (TFTR) has operated since December 1982 with ohmically heated plasmas. Routine operation with feedback control of plasma current, position, and density has been obtained for plasmas with I/sub p/ approx. = 800 kA, a = 68 cm, R = 250 cm, and B/sub t/ = 27 kG. A maximum plasma current of 1 MA was achieved with q approx. = 2.5. Energy confinement times of approx. 150 msec were measured for hydrogen and deuterium plasmas with anti n/sub e/ approx. = 2 x 10/sup 13/ cm… more
Date: November 1, 1983
Creator: Young, K.M.; Bell, M.; Blanchard, W.R.; Bretz, N.; Cecchi, J.; Coonrod, J. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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A simple model for radial expansion reactivity in LMRs (liquid metal reactors)

Description: Presented in this report is a simple analytical model developed for evaluating the radial expansion reactivity in small modular liquid metal reactors (LMRs). The present model is based on a non-leakage representation of the effective neutron multiplication factor. The resultant analytical expression for the radial expansion reactivity is simple and can be used directly in a system code for safety analyses. Applications of the present model to PRISM and SAFR resulted in a good agreement with the… more
Date: January 1, 1988
Creator: Cheng, H.S. & Van Tuyle, G.J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Electron positron factories

Description: In this paper, we will first indicate the key issues in designing a B-factory and a {phi}-factory, and illustrate the approaches that are being followed to address them. In general, reaching the B-factory parameter regime offers the most challenges, so we will emphasize it here. Then we will consider an extrapolation of our present understanding of collider performance and assess the maximum luminosity that could be anticipated. To reach extremely high luminosity, it may be necessary to conside… more
Date: December 1, 1990
Creator: Zisman, M. S.; Chattopadhyay, S.; Garren, A. A.; Lambertson, G. (Lawrence Berkeley Lab., CA (United States)); Bloom, E.; Corbett, W. J. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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A feedback for longitudinal instabilities in the SLC damping rings

Description: Longitudinal coupled bunch instabilities which are being observed in the SLC Damping Rings present a serious limitation to the ultimate luminosity of the colliding beams. It has been observed at intensities above 1 {times} 10{sup 10} particles per bunch with growth rates of the order of 10{sup 4} per second. At lower intensities we were able to control the growth by detuning the RF cavity through temperature or voltage changes. As the SLC operating intensity approaches the design value above 5 … more
Date: January 1, 1991
Creator: Chao, Y.; Corredoura, P.; Limberg, T.; Schwarz, H. & Wilson, P.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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PRD (power-reactivity-decrement) components of a homogeneous U10Zr-fueled 900 MWt LMR

Description: The linear and Doppler feedback components of the regional contributions of the power-reactivity-decrement (PRD) for a representative 900 MWt homogeneous U10Zr-fueled sodium-cooled reactor are calculated. The PRD is the reactivity required to bring the reactor from zero-power hot-critical condition to a given power level. These components are further separated into power dependent and power-to-flow dependent parts. The values are compared with corresponding quantities calculated for the Experim… more
Date: January 1, 1988
Creator: Meneghetti, D. & Kucera, D.A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Final analysis of the engineering data on the scyllac feedback stabilization experiment

Description: The feedback stabilization system consists of four basic components: plasma position detectors, a signal processor or mode analyzer driven by the position detector signals, power amplifiers which are driven by the mode analyzer, and feedback load coils driven by the power amplifiers. A short description of each of the four components of the system is presented. The location of the components in the experiment is shown.
Date: January 1, 1977
Creator: Kutac, K. J.; Kewish, R. W.; Miller, G. & Gribble, R. F.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Safety aspects of the US advanced LMR (liquid metal reactor) design

Description: The cornerstones of the United States Advanced Liquid Metal Cooled Reactor (ALMR) program sponsored by the Department of Energy are: the plant design program at General Electric based on the PRISM (Power Reactor Innovative Small Module) concept, and the Integral Fast Reactor program (IFR) at Argonne National Laboratory (ANL). The goal of the US program is to produce a standard, commercial ALMR, including the associated fuel cycle. This paper discusses the US regulatory framework for design of a… more
Date: January 1, 1989
Creator: Pedersen, D.R.; Gyorey, G. L.; Marchaterre, J. F.; Rosen, S. (Argonne National Lab., IL (USA); General Electric Co., San Jose, CA (USA); Argonne National Lab., IL (USA) et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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MHD computation of feedback of resistive-shell instabilities in the reversed field pinch

Description: MHD computation demonstrates that feedback can sustain reversal and reduce loop voltage in resistive-shell reversed field pinch (RFP) plasmas. Edge feedback on {approximately}2R/a tearing modes resonant near axis is found to restore plasma parameters to nearly their levels with a close-fitting conducting shell. When original dynamo modes are stabilized, neighboring tearing modes grow to maintain the RFP dynamo more efficiently. This suggests that experimentally observed limits on RFP pulselengt… more
Date: May 1, 1992
Creator: Zita, E.J.; Prager, S.C. (Wisconsin Univ., Madison, WI (United States). Plasma Physics Research); Ho, Y.L. & Schnack, D.D (Science Applications International Corp., San Diego, CA (United States))
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Design and test of a 40-kV, 80-A, 10-msec, neutral-beam power supply series

Description: To meet neutral-beam source requirements, a combination series switch/regulator system has been developed that can provide up to 40-kV at 80A output for 10-ms from the continuously decaying voltage of a charged capacitor bank. The system uses 100% feedback control of a series hard tube regulator. This feedback regulator is able to maintain a 40-kV output level for 100% load variations while the source voltage for the capacitor bank is drained from an initial 55-kV down to as low as 43-kV during… more
Date: October 18, 1977
Creator: North, G.G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Silicon web process development. Annual report

Description: During this reporting period significant milestones have been met. A new barrier crucible design which consistently maintains melt stability over long periods of time has been successfully tested and used in long growth runs. The pellet feeder for melt replenishment was operated continuously for growth runs of up to 17 hours (a one day growth cycle). The liquid level sensor comprising a laser/sensor system was operated, performed well, and meets the requirements for maintaining liquid level hei… more
Date: June 30, 1980
Creator: Duncan, C. S.; Seidensticker, R. G.; McHugh, J. P.; Hill, F. E.; Skutch, M. E.; Driggers, J. M. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Vertical stability requirements for ARIES-I reactor

Description: The vertical stability of the ARIES-I reactor design is analyzed with the NOVA-W, PSTAB, and TSC codes. A growth rate of {approximately}5.7 s{sup -1} is predicted for a vacuum vessel positioned behind the scrapeoff, first wall, and blanket (0.7 in inboard and 0.9 in outboard thickness) and acting as a passive stabilizer. A reactive power of {approximately}2 MV A would be required for active feedback coils located outside of the TF coils {approximately}3 m to correct a 50-mm vertical displacemen… more
Date: January 1, 1989
Creator: Bathke, C. G.; Jardin, S. C.; Leuer, J. A.; Ward, D. J. (Los Alamos National Lab., NM (USA); Princeton Univ., NJ (USA). Plasma Physics Lab.; General Atomics, San Diego, CA (USA) et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Storage Ring Development at the National Synchrotron Light Source

Description: This report contains papers on the following topics: Transverse Beam Profile Monitor; Bunch Length Measurements in the VUV Storage Ring; Photoelectric Effect Photon Beam Position Monitors; RF Receivers for Processing Electron Beam Pick-up Electrode Signals; Real-Time Global Orbit Feedback Systems; Local Orbit Feedback; Active Interlock System for High Power Insertion Devices in the X-ray Ring; Bunch Lengthening Cavity for the VUV Ring; SXLS Storage Ring Design.
Date: September 1, 1991
Creator: Krinsky, S.; Bittner, J.; Fauchet, A. M.; Johnson, E. D.; Keane, J.; Murphy, J. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Real time analysis of tokamak discharge parameters

Description: The techniques used in implementing two applications of real time analysis of data from the DIII-D tokamak are described. These tasks, which are demanding in both the speed of data acquisition and the speed of computation, execute on hardware capable of acquiring 40 million data samples per second and executing 80 million floating point operations per second. In the first case, a feedback control algorithm executing at a 10 kHz cycle frequency is used to specify the current in the poloidal fiel… more
Date: March 1, 1992
Creator: Ferron, J. R. & Strait, E. J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Stereospecificity and physiology of co-oxidative production of chemicals by methanotrophic bacteria. [Methane monooxygenase:a2]

Description: Methanotrophic bacteria can use methane as a sole source of carbon and energy. The enzyme responsible for the oxidation of methane in these organisms, methane monooxygenase, is also able to biotransform a number of substrates into industrially important chemicals. One such example is the oxidation of propylene to propylene oxide. Several strains of mesophilic and thermophilic methanotrophs have been tested for their ability to produce propylene oxide with formate, methanol, and methane as the c… more
Date: January 1, 1991
Creator: Kelley, R. L.; Hoefer, D. E.; Conrad, J. R.; Srivastava, V. J. & Akin, C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Automatic beam centering at the SSC interaction regions

Description: In the SSC interaction regions, the two colliding beams, each only a few microns in size, will have to be centered and maintained in good alignment over many hours, in order to provide the maximum possible luminosity and to minimize off-center beam-beam focussing effects. It is unlikely that sufficiently good alignment can be achieved without some kind of active feedback system, based on the beam-beam interaction rate. This memo describes such a system. In the proposed scheme, one of the beams … more
Date: March 20, 1984
Creator: Joestlein, H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Role of the Qinghai-Xizang plateau in feedback mechanisms affecting the planetary circulation

Description: It has been recognized for some time that the Qinghai-Xizang plateau is of great importance in generating planetary long-waves which, in resonance with similar waves induced by the Rocky Mountains, lead to the familiar pattern of quasi-stationary Rossby waves observed on monthly-mean upper level pressure charts. Seasonal forcing of flow patterns also appears to be particularly strong in the Qinghai-Xizang plateau region. Recent investigations suggest that the Qinghai-Xizang plateau may also be … more
Date: 1980~
Creator: Reiter, Elmar R. & Ding, Yi-Hui
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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