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LARGE SCALE DISTRIBUTED PARAMETER MODEL OF MAIN MAGNET SYSTEM AND FREQUENCY DECOMPOSITION ANALYSIS

Description: Large accelerator main magnet system consists of hundreds, even thousands, of dipole magnets. They are linked together under selected configurations to provide highly uniform dipole fields when powered. Distributed capacitance, insulation resistance, coil resistance, magnet inductance, and coupling inductance of upper and lower pancakes make each magnet a complex network. When all dipole magnets are chained together in a circle, they become a coupled pair of very high order complex ladder networks. In this study, a network of more than thousand inductive, capacitive or resistive elements are used to model an actual system. The circuit is a large-scale network. Its equivalent polynomial form has several hundred degrees. Analysis of this high order circuit and simulation of the response of any or all components is often computationally infeasible. We present methods to use frequency decomposition approach to effectively simulate and analyze magnet configuration and power supply topologies.
Date: June 25, 2007
Creator: Zhang, W.; MARNERIS, I. & SANDBERG, J.
Partner: UNT Libraries Government Documents Department

OVERVIEW OF THE AGS COLD SNAKE POWER SUPPLIES AND THE NEW RHIC SEXTUPOLE POWER SUPPLIES

Description: The two rings in the Relativistic Heavy Ion Collider (RHIC) were originally constructed with 24 sextupole power supplies, 12 for each ring. Before the start of Run 7, 24 new sextupole power supplies were installed, 12 for each ring. Individual sextupole power supplies are now each connected to six sextupole magnets. A superconducting snake magnet and power supplies were installed in the Alternating Gradient Synchrotron (AGS) and commissioned during RHIC Run 5, and used operationally in RHIC Run 6. The power supply technology, connections, control systems and interfacing with the Quench Protection system for both these systems will be presented.
Date: June 25, 2007
Creator: BRUNO,D.; GANETIS, G.; SANDBERG, J. & LOUIE, W.
Partner: UNT Libraries Government Documents Department

ANALYSIS AND SIMULATION OF MAIN MAGNET TRANSMISSION LINE EFFECT

Description: A main magnet chain forms a pair of transmission lines. Pulse-reflection-caused voltage and current differentiation throughout the magnet chain can have adverse effect on main magnet field quality. This effect is associated with magnet system configuration, coupling efficiency, and parasitic parameters. A better understanding of this phenomenon will help us in new design and existing system upgrade. In this paper, we exam the transmission line effect due to different input functions as well as configuration, coupling, and other parameters.
Date: June 25, 2007
Creator: ZHANG,W.; MARNERIS, I. & SANDBERG, J.
Partner: UNT Libraries Government Documents Department

AGS slow extracted beam improvement

Description: The Brookhaven AGS is a strong focusing accelerator which is used to accelerate protons and various heavy ion species to an equivalent proton energy of 29 GeV. Since the late 1960`s it has been serving high energy physics (HEP - proton beam) users of both slow and fast extracted beams. The AGS fixed target program presently uses primary proton and heavy ion beams (HIP) in slowly extracted fashion over spill lengths of 1.5 to 4.0 seconds. Extraction is accomplished by flattoping the main and extraction magnets and exciting a third integer resonance in the AGS. Over the long spill times, control of the subharmonic amplitude components up to a frequency of 1 kilohertz is very crucial. One of the most critical contributions to spill modulation is due to the AGS MMPS. An active filter was developed to reduce these frequencies and it`s operation is described in a previous paper. However there are still frequency components in the 60-720 Hz sub-harmonic ripple range, modulating the spill structure due to extraction power supplies and any remaining structures on the AGS MMPS. A recent scheme is being developed to use the existing tune-trim control horizontal quadrupole magnets and power supply to further reduce these troublesome noise sources. Feedback from an external beam sensor and overcoming the limitations of the quadrupole system by lead/lag compensation techniques will be described.
Date: July 1, 1997
Creator: Marneris, I.; Danowski, G.; Sandberg, J. & Soukas, A.
Partner: UNT Libraries Government Documents Department

RHIC INSERTION REGION, SHUNT POWER SUPPLY CURRENT ERRORS.

Description: The Relativistic Heavy Ion Collider (RHIC) was commissioned in 1999 and 2000. RHIC requires power supplies to supply currents to highly inductive superconducting magnets. The RHIC Insertion Region contain's many shunt power supplies to trim the current of different magnet elements in a large superconducting magnet circuit. Power Supply current error measurements were performed during the commissioning of RHIC. Models of these power supply systems were produced to predict and improve these power supply current errors using the circuit analysis program MicroCap V by Spectrum Software (TM). Results of the power supply current errors are presented from the models and from the measurements performed during the commissioning of RHIC.
Date: June 18, 2001
Creator: BRUNO,D.; GANETIS,G.; LAMBIASE,R.F. & SANDBERG,J.
Partner: UNT Libraries Government Documents Department

RUNNING THE AGS MMPS AT 5 HZ, 24 GEV.

Description: The Brookhaven Alternating Gradient Synchrotron (AGS) is a strong focusing accelerator which is used to accelerate protons and various heavy ion species to an equivalent proton enera of 29 GeV. At this energy, the maximum intensity achieved is 7 x 10{sup 13} protons per pulse. This corresponds to an average beam power of about 0.2 MW. Future programs in high-energy and neutron physics may require an upgrade of the AGS accelerator to an average beam power of around 4 MW, with proton beams at the energy of 24 GeV. This can be achieved with an increase of the beam intensity to 2 x 10{sup 14} protons per pulse that requires a 1.5-GeV super-conducting linac [1], as a new injector and by upgrading the power supply system to allow cycling at 5 beam pulses per second. This paper describes the present mode of operation of the AGS main magnet power supply, the requirements for operation at 5 Hz and a proposed sorption of all modifications required to upgrade the AGS main magnet power supply to operate at 5 HZ, with proton beams at the energy of 24 GeV.
Date: June 18, 2001
Creator: MARNERIS,I.; ROSER,T.; RUGGIERO,A.G. & SANDBERG,J.
Partner: UNT Libraries Government Documents Department

CONCEPTUAL DESIGN STUDY OF HORN POWER SUPPLY.

Description: A 250 kA pulsed power supply is required for the focusing horn of the proposed Brookhaven AGS Super Neutrino Beam Facility for long baseline neutrino oscillation experiment. It is expected to pulse at 2.5 Hz repetition rate. A preliminary study is being conducted to explore the key issues associated with the power supply system design. Advanced technologies used in similar systems as well as new ideas are being examined, simulated and evaluated. This power supply will be a very high stored energy, high average power, and high peak power system.
Date: June 16, 2003
Creator: ZHANG,W.; SANDBERG,J. & WENG,W.T.
Partner: UNT Libraries Government Documents Department

GAS DISCHARGE SWITCH EVALUATION FOR RHIC BEAM ABORT KICKER APPLICATION.

Description: A gas discharge switch EEV HX3002 is being evaluated at Brookhaven National Laboratory as a possible candidate of RHIC Beam Abort Kicker modulator main switch. At higher beam energy and higher beam intensity, the switch stability becomes very crucial. The hollow anode thyratron used in the existing system is not rated for long reverse current conduction. The reverse voltage arcing caused thyratron hold-off voltage de-rating has been the main limitation of the system operation. To improve the system reliability, a new type of gas discharge switch has been suggested by Marconi Applied Technology for its reverse conducting capability.
Date: June 30, 2002
Creator: ZHANG,W.; SANDBERG,J.; SHELDRAKE,R. & PIRRIE,C.
Partner: UNT Libraries Government Documents Department

AGS slow extraction improvements

Description: Improvement of the straightness of the F5 copper septum increased the AGS slow extraction efficiency from approx. 80% to approx. 90%. Installation of an electrostatic septum at H2O, 24 betatron wavelengths upstream of F5, further improved the extraction efficiency to approx. 97%.
Date: January 1, 1979
Creator: Glenn, J.W.; Smith, G.A.; Sandberg, J.N.; Repeta, L. & Weisberg, H.
Partner: UNT Libraries Government Documents Department

Analysis of RHIC beam dump pre-fires

Description: It has been speculated that the beam may cause instability of the RHIC Beam Abort Kickers. In this study, we explore the available data of past beam operations, the device history of key modulator components, and the radiation patterns to examine the correlations. The RHIC beam abort kicker system was designed and built in the 90's. Over last decade, we have made many improvements to bring the RHIC beam abort kicker system to a stable operational state. However, the challenge continues. We present the analysis of the pre-fire, an unrequested discharge of kicker, issues which relates to the RHIC machine safety and operational stability.
Date: March 28, 2011
Creator: Zhang, W.; Ahrens, L.; Fischer, W.; Hahn, H.; Mi, J.; Sandberg, J. et al.
Partner: UNT Libraries Government Documents Department

Booster main magnet power supply, present operation and potential future upgrades

Description: The Brookhaven Booster Main Magnet Power Supply (MMPS) is a 24 pulse thyristor control supply, rated at 5500 Amps, +/-2000 Volts, or 3000 Amps, +/-6000 Volts. The power supply is fed directly from the power utility and the peak magnet power is 18 MWatts. This peak power is seen directly at the incoming ac line. This power supply has been in operation for the last 18 years. This paper will describe the present topology and operation of the power supply, the feedback control system and the different modes of operation of the power supply. Since the power supply has been in operation for the last 18 years, upgrading this power supply is essential. A new power supply topology has been studied where energy is stored in capacitor banks. DC to DC converters are used to convert the dc voltage stored in the capacitor banks to pulsed DC voltage into the magnet load. This enables the average incoming power from the ac line to be constant while the peak magnet power is pulsed to +/- 18 MWatts. Simulations and waveforms of this power supply will be presented.
Date: March 28, 2011
Creator: Bajon, E.; Bannon, M.; Marneris, I.; Danowski, G.; Sandberg, J. & Savatteri, S.
Partner: UNT Libraries Government Documents Department

RHIC POWER SUPPLIES-FAILURE STATISTICS FOR RUNS 4, 5, AND 6

Description: The two rings in the Relativistic Heavy Ion Collider (RFIIC) require a total of 933 power supplies to supply current to highly inductive superconducting magnets. Failure statistics for the RHIC power supplies will be failure associated with the CEPS group's responsibilities. presented for the last three RHIC runs. The failures of the power supplies will be analyzed. The statistics associated with the power supply failures will be presented. Comparisons of the failure statistics for the last three RHIC runs will be shown. Improvements that have increased power supply availability will be discussed.
Date: June 25, 2007
Creator: BRUNO,D.; GANETIS, G.; SANDBERG, J.; LOUIE, W.; HEPPNER, G. & SCHULTHEISS, C.
Partner: UNT Libraries Government Documents Department

SIMULATIONS OF THE AGS MMPS STORING ENERGY IN CAPACITOR BANKS

Description: The Brookhaven AGS Main Magnet Power Supply (MMPS) is a thyristor control supply rated at 5500 Amps, +/-9000 Volts. The peak magnet power is 50 MWatts. The power supply is fed from a motor/generator manufactured by Siemens. The generator is 3 phase 7500 Volts rated at 50 MVA. The peak power requirements come from the stored energy in the rotor of the motor/generator. The motor generator is about 45 years old, made by Siemens and it is not clear if companies will be manufacturing similar machines in the future. We are therefore investigating different ways of storing energy for future AGS MMPS operations. This paper will present simulations of a power supply where energy is stored in capacitor banks. Two dc to dc converters will be presented along with the control system of the power section. The switching elements will be IGCT's made by ABB. The simulation program used is called PSIM version 6.1. The average power from the local power authority into the power supply will be kept constant during the pulsing of the magnets at +/-50 MW. The reactive power will also be kept constant below 1.5 MVAR. Waveforms will be presented.
Date: June 25, 2007
Creator: MARNERIS,I.; BADEA, V.S.; BONATI, R.; ROSER, T. & SANDBERG, J.
Partner: UNT Libraries Government Documents Department

A SIMPLIFIED APPROACH TO ANALYZE AND MODEL INDUCTIVE VOLTAGE ADDER

Description: We have recently developed a simplified model and a set of simple formulas for inductive voltage adder design. This model reveals the relationship of output waveform parameters and hardware designs. A computer simulation has demonstrated that parameter estimation based on this approach is accurate as compared to an actual circuit. This approach can be used in early stages of project development to assist feasibility study, geometry selection in engineering design, and parameter selection of critical components. In this paper, we give the deduction of a simplified model. Among the estimation formulas we present are those for pulse rise time, system impedance, and number of stages. Examples are used to illustrate the advantage of this approach. This approach is also applicable to induction LINAC design.
Date: June 25, 2007
Creator: ZHANG,W.; ENG, W.; PAI, C.; SANDBERG, J.; TAN, Y. & TIAN, Y.
Partner: UNT Libraries Government Documents Department

INDUCTIVE VOLTAGE ADDER NETWORK ANALYSIS AND MODEL SIMPLIFICATION.

Description: Inductive voltage adder topology has attracted great attentions in pulse power community for near two decades. However, there has been lack of literatures on inductive voltage adder network analysis and circuit design model. We have recently developed a simplified model and a set of simple formulas. An expanded model and more detailed analysis are presented in this paper. Our model reveals the relationship of output waveform parameters and hardware designs. Computer simulations have demonstrated that parameter estimation based on this approach is accurate. This approach can be used in early stages of project development to assist feasibility study, geometry selection in engineering design, and parameter selection of critical components. A set of fundamental estimation formulas including system impedance, rise time, and number of stages are presented. This approach is also applicable to induction LINAC design. In addition, the model presented in this paper shows a new topology of high voltage waveform generator.
Date: June 17, 2007
Creator: ZHANG,W.; NG, W.; PAI, C.; SANDBERG, J.; TAN, Y. & TIAN, Y.
Partner: UNT Libraries Government Documents Department

High power fast ramping power supplies

Description: Hundred megawatt level fast ramping power converters to drive proton and heavy ion machines are under research and development at accelerator facilities in the world. This is a leading edge technology. There are several topologies to achieve this power level. Their advantages and related issues will be discussed.
Date: May 4, 2009
Creator: Marneris,I.; Bajon, E.; Bonati, R.; Sandberg, J.; Roser, T. & Tsoupas, N.
Partner: UNT Libraries Government Documents Department

RHIC BEAM ABORT KICKER POWER SUPPLY SYSTEM COMMISSIONING EXPERIENCE AND REMAINING ISSUES.

Description: The RHIC Beam Abort Kicker Power Supply Systems commissioning experience and the remaining issues will be reported in this paper. The RHIC Blue Ring Beam Abort Kicker Power Supply System initial commissioning took place in June 1999. Its identical system in Yellow Ring was brought on line during Spring 2000. Each of the RHIC Beam Abort Kicker Power Supply Systems consists of five high voltage modulators and subsystems. These systems are critical devices for RHIC machine protection and environmental protection. They are required to be effective, reliable and operating with sufficient redundancy to safely abort the beam to its beam dump at the end of accumulation or at any time when they are commanded. To deflect 66 GeV ion beam to the beam absorbers, the RHIC Beam Abort Kicker Power Supply Systems were operated at 22 kV level. The RHIC 2000 commissioning run was very successful.
Date: June 18, 2001
Creator: ZHANG,W.; AHRENS,L.A.; MI,J.; OERTER,B.; SANDERS,R. & SANDBERG,J.
Partner: UNT Libraries Government Documents Department