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Sandberg, J.

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MOPAS090 Overview of the AGS Cold Snake Power Supplies and the new RHIC Sextupole Power Supplies 637
 
  • D. Bruno, G. Ganetis, W. Louie, J. Sandberg
    BNL, Upton, Long Island, New York
 
  Funding: Work performed under Contract No. DE-AC02-98CH10886 with the U. S. Department of Energy.

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.

 
MOPAS091 RHIC Power Supplies-Failure Statistics for Runs 4, 5 and 6 640
 
  • D. Bruno, G. Ganetis, G. Heppner, W. Louie, J. Sandberg, C. Schultheiss
    BNL, Upton, Long Island, New York
 
  Funding: Work performed under Contract No. DE-AC02-98CH10886 with the U. S. Department of Energy.

The two rings in the Relativistic Heavy Ion Collider (RHIC) require a total of 933 power supplies to supply current to highly inductive superconducting magnets. Failure statistics for the RHIC power supplies will be 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. Further improvements to increase the availability of the power supplies will also be discussed.

 
MOPAS096 Simulations of the AGS MMPS Storing Energy in Capacitor Banks 652
 
  • I. Marneris, S. V. Badea, R. Bonati, T. Roser, J. Sandberg
    BNL, Upton, Long Island, New York
 
  Funding: Work performed under the auspices of the US Department of Energy

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 and Siemens is not manufacturing similar machines in the future. We are therefore investigating different ways of storing energy for future AGS MMPS operation. This paper will present simulations of a power supply where energy is stored in capacitor banks. Two dc to dc converters will be presented. The switching elements would be IGCT's made by ABB. The simulation program used is called PSIM Version 6.1. The control system of the power supply will also be presented. The average power from the Long Island Power Authority (LIPA) 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.

 
MOPAS104 Large Scale Distributed Parameter Model of Main Magnet System and Frequency Decomposition Analysis 670
 
  • W. Zhang, I. Marneris, J. Sandberg
    BNL, Upton, Long Island, New York
 
  Funding: Work performed under auspices of U. S. Department of Energy.

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.

 
MOPAS105 Analysis and Simulation of Main Magnet Transmission Line Effect 673
 
  • W. Zhang, I. Marneris, J. Sandberg
    BNL, Upton, Long Island, New York
 
  Funding: Wor performed under auspices of U. S. Departemnt of Energy.

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.

 
WEPMS092 A Simplified Approach to Analyze and Model Inductive Voltage Adder 2553
 
  • W. Zhang, W. Eng, C. Pai, J. Sandberg, Y. Tan, Y. Tian
    BNL, Upton, Long Island, New York
 
  Funding: Work performed under auspices of U. S. Departemnt of Energy.

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.

 
TUOCKI02 Summary of the RHIC Performance during the FY07 Heavy Ion Run 722
 
  • K. A. Drees, L. Ahrens, J. G. Alessi, M. Bai, D. S. Barton, J. Beebe-Wang, M. Blaskiewicz, J. M. Brennan, K. A. Brown, D. Bruno, J. J. Butler, R. Calaga, P. Cameron, R. Connolly, T. D'Ottavio, W. Fischer, W. Fu, G. Ganetis, J. W. Glenn, M. Harvey, T. Hayes, H.-C. Hseuh, H. Huang, J. Kewisch, R. C. Lee, V. Litvinenko, Y. Luo, W. W. MacKay, G. J. Marr, A. Marusic, R. J. Michnoff, C. Montag, J. Morris, B. Oerter, F. C. Pilat, V. Ptitsyn, T. Roser, J. Sandberg, T. Satogata, C. Schultheiss, F. Severino, K. Smith, S. Tepikian, D. Trbojevic, N. Tsoupas, J. E. Tuozzolo, A. Zaltsman, S. Y. Zhang
    BNL, Upton, Long Island, New York
 
  Funding: Work performed under Contract Number DE-AC02-98CH10886 under the auspices of the US Department of Energy.

After the last successful RHIC Au-Au run in 2004 (Run-4), RHIC experiments now require significantly enhanced luminosity to study very rare events in heavy ion collisions. RHIC has demonstrated its capability to operate routinely above its design average luminosity per store of 2x1026 cm-2 s-1. In Run-4 we already achieved 2.5 times the design luminosity in RHIC. This luminosity was achieved with only 40% of bunches filled, and with β* = 1 m. However, the goal is to reach 4 times the design luminosity, 8x1026 cm-2 s-1, by reducing the beta* value and increasing the number of bunches to the accelerator maximum of 111. In addition, the average time in store should be increased by a factor of 1.1 to about 60% of calendar time. We present an overview of the changes that increased the instantaneous luminosity and luminosity lifetime, raised the reliability, and improved the operational efficiency of RHIC Au-Au operations during Run-7.

 
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