• C. Rodrigues
  
• A. R. Silva
  LNLS, Campinas

• C. Rodrigues
  
• L. H. Oliveira, A. R. Silva
  LNLS, Campinas

• M. Lonza
  
• D. Bulfone, V. Forchi', G. Gaio
  ELETTRA, Basovizza, Trieste

• K. Fan
  
• Y. Arakaki, I. Sakai
  KEK, Ibaraki

• H. Sato
  
• T. Ise, Y. Miura
  Osaka University, Suita
• S. Nomura
  Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Tokyo
• t.s. Shintomi, M. J. Shirakata
  KEK, Ibaraki

• M. Wake
  
• Y. Arakida, K. Koseki, Y. Shimosaki, K. Takayama, K. T. Torikai
  KEK, Ibaraki
• W. Jiang, K. Nakahiro
  Nagaoka University of Technology, Nagaoka, Niigata
• A. Sugiyama
  Shindengen Co., Ltd., Tokyo
• A. Tokuchi
  Nichicon (Kusatsu) Corporation, Shiga

• I.-S. Hong
  
• Y.-G. Song
  KAERI, Daejon

20MeV proton linear accelerator of the PEFP(Proton Engineering Frontier Project) has above 10 magnet power supplies and getter pumps to interface with Modbus protocol. VME IOC(Input Output Controller) has been designed and constructed for the control system by using VME serial I/O. The driver support module of the VME IOC has been developed to initialize the IO board and communicate with the instruments through EPICS. Operating console and storage module for operators in the control room has been programmed on PC and SUN of the operator interface.

• Y.-G. Song
  
• Y.-S. Cho, I.-S. Hong
  KAERI, Daejon

Proton Engineering Frontier Project (PEFP) has above 40 magnet power supplies for the 20MeV proton linac. Because some power supplies have analog interfaces, we chose ATEC (Analog Input To Ethernet Converter) to monitor their output currents and voltage by supporting the protocol conversion function. Software components of the Experimental Physics and Industrial Control System (EPICS) have been ported to a VME single board computer based on a PowerPC microprocessor (MPC7410). This paper presents the software component and processing of analog input values between EPICS on the PowerPC based board and ATEC operating as Server Mode.

• S.-C. Kim
  
• J. Choi, K. M. Ha, J. Y. Huang
  PAL, Pohang, Kyungbuk

At 2006, PLS Linac magnet power supply (MPS) has been upgraded for the stable beam injection and 4th generation light source research. New MPS are developed new compact MPS of 16-bit resolution and 20ppm stability using four-quadrant switching scheme with 50kHz MOSFET switching device, and consists of main power board, control power board, regulator board and CPU board. Size of each board is only 100mm width and 240mm depth. Output of MPS is 10V, ±10A for the bipolar and 50V, 50A for the unipolar magnet. Main board is consisted four-quadrant FET switch, driver and output filter. Output filter must be perfectly eliminating switch frequency and compact size. In this paper, we report on development and characteristics of compact output filter of the new MPS for PAL linac.

• J. Dedic
  
• D. Golob, A. Hasanovic, M. Plesko
  Cosylab, Ljubljana

• Y.-C. Chien
  
• K. H. Hu, K.-B. Liu, H. M. Shih
  NSRRC, Hsinchu

• C.-Y. Liu
  
• K.-B. Liu, H. M. Shih
  NSRRC, Hsinchu

• M. C. Hughes
  
• J. W. Gray
  STFC/RAL/ISIS, Chilton, Didcot, Oxon

* M. G. White et al., A 3-BeV High Intensity Proton Synchrotron, The Princeton-Pennsylvania Accelerator, CERN Symp.1956 Proc., p525.

• S. Cohen
  
• M. W. Sherman, W. D. Sherman
  Alpha Scientific Electronics, Hayward, CA

• S. Cohen
  
• S. R. Babel
  Bira, Albuquerque, New Mexico

• G. Feng
  
• B. Deriy, J. Wang
  ANL, Argonne, Illinois

Due to the circuit topology of ramping power supplies used in the APS Booster ring, they are unable to follow the linear current ramp to the desired accuracy of 0.1%. In addition, those supplies are also sensitive to AC line perturbation. To improve the performance, a linear regulator using paralleled MOSFET devices in series with the power supply is proposed. The control algorithm uses a real-time current feedback loop to force the MOSFETs to work in the linear operation mode. By using this linear MOSFET regulator, the MOSFETs' drain to source voltage, and hence the voltage imposed on magnets can be regulated very quickly. As a result, the regulation of the magnet current can be improved significantly. So far the simulation results show that with the linear regulator the current regulation can be improved to better than 0.1%. Because of the high bandwidth of the linear regulator, it can reduce the harmonic content in the output current as well as the noises due to the AC line disturbance. A sextupole power supply has been set up to verify the proposed topology. This paper discusses the circuit topology, the regulation algorithm, and the experiment results.

• D. R. Walters
  

A prototype vacuum chamber is under development at the Advanced Photon Source for use in the Linac Coherent Light Source at Stanford Linear Accelerator Center. The chamber will be fabricated from the austenite stainless steels. The chamber requires a continuous aluminum coating on the inner surface in order to reduce the wakefield losses to a level within the resistivity budget. The method being presented here is unique in that it can be applied to a fully fabricated chamber 5 mm high, 11.5 mm wide, and 3460 mm long. In existing methods the chamber aperture has been much larger than is used here. This paper describes a method applicable for these smaller cross sections. This process uses a pair of small electrodes, centered in the aperture, where they are attached to a high frequency AC power supply. In this configuration each electrode is connected to the opposite polarity of the other. The chamber cavity is filled with argon gas to facilitate the formation of a glow discharge causing the aluminum electrodes to sputter onto the chamber walls. This paper presents the laboratory test results from small samples up to the full-sized assemblies.

• C. C. Drennan
  
• M. Ball, A. R. Franck, D. J. Harding, P. A. Kasley, G. E. Krafczyk, M. J. Kucera, J. R. Lackey, D. McArthur, J. R. Misek, W. Pellico, E. Prebys, A. K. Triplett, D. Wolff
  Fermilab, Batavia, Illinois

To better control the beam position, tune, and chromaticity in the Fermilab Booster synchrotron, a new package of six corrector elements has been designed, incorporating both normal and skew orientations of dipole, quadrupole, and sextupole magnets. The devices are under construction and will be installation in 48 locations in the Booster accelerator. Each of these 288 corrector magnets will be individually powered. Each of the magnets will be individually controlled using operator programmed current ramps designed specifically for the each type of Booster acceleration cycle. This paper provides an overview of the corrector magnet installation in the accelerator enclosure, power and sensor interconnections, specifications for the switch-mode power supplies, rack and equipment layouts, controls and interlock electronics, and the features of the operator interface for programming the current ramps and adjusting the timing of the system triggers.

• S. P. Virostek
  
• M. A. Green, D. Li, M. S. Zisman
  LBNL, Berkeley, California

The Muon Ionization Cooling Experiment (MICE) will demonstrate ionization cooling in a short section of a realistic cooling channel using a muon beam at Rutherford Appleton Laboratory (RAL) in the UK. A five-coil, superconducting spectrometer solenoid magnet at each end of the cooling channel will provide a 4 T uniform field region for the scintillating fiber tracker within the magnet bore tubes. The tracker modules are used to measure the muon beam emittance as it enters and exits the cooling channel. The cold mass for the 400 mm warm bore magnet consists of two sections: a three-coil spectrometer magnet and a two-coil matching section that matches the uniform field of the solenoid into the MICE cooling channel. The detailed design and analysis of the two spectrometer solenoids has been completed, and the fabrication of the magnets is in its final stages. The primary features of the spectrometer solenoid magnetic and mechanical designs are presented along with a summary of key fabrication issues and photos of the fabrication process.

• M. A. Green
  
• X. L. Guo, G. Han, L. Jia, L. K. Li, S. Y. Li, C. S. Liu, X. K. Liu, L. Wang, H. Wu, F. Y. Xu
  ICST, Harbin
• S. P. Virostek
  LBNL, Berkeley, California

The Muon Ionization Cooling Experiment (MICE) will demonstrate ionization cooling in a short section of a realistic cooling channel using a muon beam at Rutherford Appleton Laboratory (RAL) in the UK. The MICE RF and Coupling Coil Module comprises a superconducting solenoid mounted around four normal conducting 201.25-MHz RF cavities. Each cavity has a pair of thin curved beryllium windows to close the conventional open beam irises. The coil package that surrounds the RF cavities is to be mounted on the outside of a 1.4 m diameter vacuum vessel. The coupling coil confines the beam in the cavity module and, in particular, within the radius of the cavity beam windows. The two MICE coupling solenoids will be operated in series using a 300 A, 10 V power supply. The maximum longitudinal force that will be carried by the cold mass support system is 0.5 MN during the expected operating and failure modes of the experiment. The detailed design and analysis of the two coupling coils has been completed, and the fabrication of the magnets is under way. The primary magnetic and mechanical design features of the coils are presented along with a summary of key fabrication issues.

• J. M. Weber
  
• M. J. Chin, CA. Timossi, E. C. Williams
  LBNL, Berkeley, California

The emergence of Field Programmable Gate Arrays (FPGAs) with embedded processors and significant progress in their development tools have contributed to the realization of system-on-a-chip networked front-end systems. Embedded processors are capable of running full-fledged Real-Time Operating Systems (RTOSs) and serving channels via Ethernet while high speed hardware functions, such as digital signal processing and high performance interfaces, run simultaneously in the FPGA logic. Despite significant advantages of the system-on-a-chip implementation, engineers have shied away from designing such systems due to the perceived daunting task of integrating software to run a RTOS with custom hardware. However, advances in embedded development tools considerably reduce the effort required for software/hardware integration. This paper will describe the implementation and integration of software and hardware in an FPGA embedded processor system as illustrated by the design of a new control system module for the ALS.

• S. M. Hartman
  
• S. F. Mikhailov, V. Popov, Y. K. Wu
  FEL/Duke University, Durham, North Carolina

At Duke University, a booster synchrotron was recently commissioned as part of the HIGS upgrade. For the ramping magnet power supply controls, a scheme was developed to present the high level operator interface in terms of the physics quantities of the accelerator, i.e. the effective focusing strength of the magnets. This scheme allows for the nonlinearities of the magnets – a result of the extremely compact footprint of this booster – to be incorporated into the low level software. This facilitates machine studies and simplifies use of physics modeling. In addition, it simplifies operation, allowing the booster to ramp to any energy from the 0.27 GeV of the injector linac to the 1.2 GeV maximum of the Duke Storage Ring. The high level of flexibility of this system if further advanced by incorporating the level of tunability typically found in a storage ring control system. Tuning changes made during steady-state operation are automatically propagated to the waveforms which make up the booster ramp. This approach provides a good match to the wide operation modes of the Duke Storage Ring and its associated free electron laser, and may useful for other compact booster synchrotrons.

• V. Popov
  
• M. D. Busch, S. M. Hartman, S. F. Mikhailov, O. Oakeley, P. W. Wallace, Y. K. Wu
  FEL/Duke University, Durham, North Carolina

A booster synchrotron has been recently commissioned at Duke University as part of the High Intensity Gamma-ray Source (HIGS) upgrade. All dipole and quadrupole magnets are fed by the same power supply in order to facilitate synchronization. A 500kW retired thyristor controlled power supply has been completely rebuilt to provide high accuracy ramping of current in the range between 150A and 700A in a 1.3 sec repetition cycle. Reproducibility of current at extraction energy is better than 0.1% for entire operational range of energy. Conflict of a fast ramping operation and a magnet protection in the case of emergency shutdown was resolved using additional thyristor switches. All trim power supplies involved in ramp have been matched with the main power supply for the time response and voltage range. The injection and extraction schemes require rapidly ramping Y-correctors. The required peak power about 4 kW in these correctors is provided by a combining a low voltage DC power supply and a pulse boosting circuit. We present the challenges of designing and developing booster power supply system. And also we report measured performance and operational experience in this paper.

• J. T. Bradley III
  
• C. J. Andrews, L. F. Fernandez, M. F. Fresquez, W. Reass, W. Roybal, J. B. Sandoval
  LANL, Los Alamos, New Mexico

The proton beam in the LANSCE accelerator is guided and focused almost exclusively by electromagnets. Magnet hysteresis has had significant impacts on the tuning of the LANSCE accelerator.* Magnet hysteresis can also have an impact on Magnet Power Supply (MPS) control, regulation and repeatability requirements. To date, MPS performance requirements have been driven by the requirements on the magnetic fields as determined by the accelerator physicists. Taking hysteresis effects into account can significantly change MPS requirements, as some requirements become more stringent and some are found to be overspecified. Overspecification of MPS requirements can result in significant increases in MPS cost. Conversely, the use of appropriate MPS requirements can result in significant cost savings. The LANSCE accelerator's more than three decades of operation provide a wide variety of magnet power supply technologies and operational experience. We will survey the LANSCE magnet power supply history and determine how performance specifications can be refined to both reduce costs and improve the operators abilities to control the magnetic fields.

*R. McCrady, "Mitigation Of Magnet Hysteresis Effects at LANSCE", LINAC 2006, August, 2006.

• A. Chan
  
• P. Bellomo, G. R. Crane, P. Emma, E. Grunhaus, K. Luchini, I. A. MacGregor, D. S. Marsh, R. Pope, P. L. Prickett, E. Rago, K. Ratcliffe, T. Shab
  SLAC, Menlo Park, California

Changes to beamline optics may effect many engineering processes downstream. In the past, we incorporated these changes manually into disparate engineering spreadsheets. At LCLS, database applications have been developed in order to compare and clearly display differences amongst various versions of beamline optics files. These applications also incorporate the changes into engineering databases, after they have been validated by the engineers. This allows the engineers to be notified, and modifications to be made if beamline optics changes require corresponding adjustments of engineering elements. This paper will describe how this streamlines the workflow, and also provides greater reliability in how beamline optics changes are integrated into engineering databases (such as cabling, power supplies, inventory). The paper includes a description of the related LCLS inventory system, which also serves as a repository for quality assurance documents. The underlying database schemas and applications will be outlined.

• B. Lam
  
• P. Bellomo, D. Macnair, A. C. de Lira
  SLAC, Menlo Park, California

In 2008 KEK is commissioning ATF2 - an extension to the existing ATF. ATF2 is a mockup of the final focus test beam accelerator envisioned in the ILC. SLAC is designing the power supply systems for the dc magnets in the ATF2, which will require 38 power supplies ranging from 1.5 to 6 kW, currents from 50 to 200 A, all rated at output voltages not higher than 30 V. Because of the extensive quantities of magnets required for the ILC, high availability is paramount to its successful operation, so the power supply topology chosen for the ATF2 uses N+1 redundancy, with 50-A power modules to construct each power supply. These power modules are current-mode buck regulators, which operate in parallel with each other and one redundant module. One bulk power supply provides off-the-line regulated dc input to a number of the power supplies. Current stability requirements for the magnets range from 10 to 10⁰⁰ ppm. A precision current transductor and a recently developed SLAC-built 20-bit Ethernet Power Supply Controller will provide the current regulation required. In this paper we present the conceptual design, prototype results, and the status of the power supply systems for the ATF2.

• A. C. de Lira
  
• P. Bellomo, K. Luchini, D. Macnair
  SLAC, Menlo Park, California

The LCLS injector at SLAC requires 100+ dc-magnet power supply systems for its operation. Power supplies are divided into two main groups: intermediate rack-mounted type for output powers up to 20 kW at 375 A, and bipolar units rated 6 A, 12 A, and 30 A for corrector magnets and small quadrupoles. The intermediate power supplies are controlled by a 20-bit Ethernet power supply controller, specially developed at SLAC to be used in this project. The bipolar units are controlled via 12-bit DACs and ADCs housed in a VME crate. EPICS is the controls interface to all systems. For all systems, stability requirements are better than 10⁰⁰ ppm. The Power Conversion Department at SLAC, in close cooperation with the LCLS Controls group, was responsible for defining the major characteristics of the power supply systems, their specification, procurement, installation, and commissioning. In this paper we describe the main characteristics of the power supply systems for the LCLS injector, including results from their successful commissioning early this year.

• L. Bees
  
• L. Simpson, A. Tydeman
  Lambda, Neptune, New Jersey

• G. H. Biallas
  
• N. T. Belcher
  The College of William and Mary, Williamsburg
• D. Douglas, T. Hiatt, K. Jordan
  Jefferson Lab, Newport News, Virginia

Two styles of Panofsky Quadrupoles with integral corrector dipole windings are in use in the electron beam line of the Free Electron Laser at Jefferson Lab. We combined the functions into single magnets, adding hundreds of Gauss-cm dipole corrector capability to existing quadrupoles because space is at a premium along the beam line. Superposing high quality dipole corrector field on a high quality, weak (600 to 1'000 Gauss) quadrupole is possible because the parallel slab iron yoke of the Panofsky Quadrupole acts as a window frame style dipole yoke. The dipole field is formed when two current sources, designed and made at Jlab, add and subtract current from the two opposite quadrupole current sheet windings parallel to the dipole field direction. The current sources also drive auxiliary coils at the yoke's inner corners that improve the dipole field. Magnet measurements yielded the control system field maps that characterize the two types of fields. Details of field analysis using OPERA, construction methods, wiring details, magnet measurements and the current sources are presented.

• D. Bruno
  
• G. Ganetis, W. Louie, J. Sandberg
  BNL, Upton, Long Island, New York

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.

• D. Bruno
  
• G. Ganetis, G. Heppner, W. Louie, J. Sandberg, C. Schultheiss
  BNL, Upton, Long Island, New York

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.

• I. Marneris
  
• S. V. Badea, R. Bonati, T. Roser, J. Sandberg
  BNL, Upton, Long Island, New York

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.

• W. Zhang
  
• I. Marneris, J. Sandberg
  BNL, Upton, Long Island, New York

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.

• W. Zhang
  
• I. Marneris, J. Sandberg
  BNL, Upton, Long Island, New York

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.

• R. L. Cassel
  
• S. Hitchcock
  Stangenes Industries, Palo Alto, California

• C. Spackman
  
• A. Deyhim
  Physics Teachers Association, Knoxville, Tennessee
• E. A. Johnson
  Advanced Design Consulting, Inc, Lansing, New York
• J. T. Thånell, E. J. Wallen
  MAX-lab, Lund

Advanced Design Consulting developed control software entitled IDcontrol for its state-of-the-art Apple II insertion devices (ID). These IDs feature 8 controllable axes: four servo motors control the gap and taper of two main girders, and four servo motors control the photon polarization-state by manipulating four sub-girders. IDcontrol simultaneously positions all 8 axes with high precision in real-time using 0.1 micron linear encoders attached directly to the girders and sub-girders. Helical and Inclined Plane phase modes are supported with automated mode switching. Magnetic-field-correction-coil current and girder taper are adjustable as functions of gap, phase, and phase mode. IDcontrol continuously monitors redundant encoder velocity and position data for maximal reliability, encoder failure detection, and damage prevention. Combined with ADCs Graphical User Interface (GUI) entitled IDgui, IDcontrol manipulates the ID, provides user notification and automated recovery from errors, management of correction data, and isometric visualization of the ID's girders. The functionality of both IDcontrol and IDgui has been demonstrated at MAX lab and the results will be discussed.

• V. Litvinenko
  
• J. Alduino, D. Beavis, I. Ben-Zvi, M. Blaskiewicz, J. M. Brennan, A. Burrill, R. Calaga, P. Cameron, X. Chang, K. A. Drees, G. Ganetis, D. M. Gassner, J. G. Grimes, H. Hahn, L. R. Hammons, A. Hershcovitch, H.-C. Hseuh, A. K. Jain, D. Kayran, J. Kewisch, R. F. Lambiase, D. L. Lederle, C. Longo, G. J. Mahler, G. T. McIntyre, W. Meng, T. C. Nehring, B. Oerter, C. Pai, D. Pate, D. Phillips, E. Pozdeyev, T. Rao, J. Reich, T. Roser, T. Russo, Z. Segalov, J. Smedley, K. Smith, J. E. Tuozzolo, G. Wang, D. Weiss, N. Williams, Q. Wu, K. Yip, A. Zaltsman
  BNL, Upton, Long Island, New York
• H. Bluem, M. D. Cole, A. J. Favale, D. Holmes, J. Rathke, T. Schultheiss, A. M.M. Todd
  AES, Princeton, New Jersey
• B. W. Buckley
  CLASSE, Ithaca
• G. Citver
  Stony Brook University, StonyBrook
• J. R. Delayen, L. W. Funk, H. L. Phillips, J. P. Preble
  Jefferson Lab, Newport News, Virginia

In this paper we present status and plans for the 20-MeV R&D energy recovery linac, which is under construction at Collider Accelerator Department at BNL. The facility is based on high current (up to 0.5 A of average current) super-conducting 2.5 MeV RF gun, single-mode super-conducting 5-cell RF linac and about 20-m long return loop with very flexible lattice. The R&D ERL, which is planned for commissioning in 2008, aims to address many outstanding questions relevant for high current, high brightness energy-recovery linacs.

• P. A. Elkiaer
  
• S. L. Birch, E. P. Quinn, S. P. Stoneham
  STFC/RAL/ISIS, Chilton, Didcot, Oxon
• C. E. Hansen, N. Hauge, C. Nielsen, E. Steinmann
  Danfysik A/S, Jyllinge
• A. Morris
  STFC/RAL/ASTeC, Chilton, Didcot, Oxon

• Y. Shimosaki
  
• Y. Arakida, T. Iwashita, T. Kono, E. Nakamura, K. Takayama, M. Wake
  KEK, Ibaraki
• T. S. Dixit
  GUAS/AS, Ibaraki
• N. Nagura, K. Okazaki, K. Otsuka
  Nippon Advanced Technology Co. Ltd., Ibaraki-prefecture
• K. T. Torikai
  NIRS, Chiba-shi

* K. Takayama, presented in PAC07.

• M. Yoshii
  
• S. Anami, E. Ezura, K. Hara, Y. Hashimoto, C. Ohmori, A. Takagi, M. Toda
  KEK, Ibaraki
• K. Haga, K. Hasegawa, M. Nomura, A. Schnase, F. Tamura, M. Yamamoto
  JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken

masahito.yoshii@kek.jp

• M. Yamamoto
  
• S. Anami, E. Ezura, K. Hara, C. Ohmori, A. Takagi, M. Toda, M. Yoshii
  KEK, Ibaraki
• K. Hasegawa, M. Nomura, A. Schnase, F. Tamura
  JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken

• A. Seville
  
• D. J. Adams, C. W. Appelbee, D. Bayley, N. E. Farthing, I. S.K. Gardner, M. G. Glover, B. G. Pine, J. W.G. Thomason, C. M. Warsop
  STFC/RAL/ISIS, Chilton, Didcot, Oxon

• A. V. Aleksandrov
  
• C. Deibele
  ORNL, Oak Ridge, Tennessee

The chopper system for the Spallation Neutron Source (SNS) provides a gap in the beam for clean extraction from the accumulator ring. It consists of a pre-chopper in the low energy beam transport and a faster chopper in the medium energy beam transport (MEBT). The original "meander line" design of the MEBT chopper deflector was successfully tested with low power beam during the SNS linac commissioning but turned out to be unsuitable for high power beam operation due to poor cooling of the copper strip line through the dielectric substrate. We developed a new deflecting structure, with higher deflection efficiency and with rise and fall time easily customizable to match the available high voltage pulse generator. In this paper we describe design, implementation and beam tests results of the new MEBT chopper deflector.

• T. Satogata
  
• L. Ahrens, M. Bai, J. M. Brennan, D. Bruno, J. J. Butler, K. A. Drees, A. V. Fedotov, W. Fischer, M. Harvey, T. Hayes, W. Jappe, R. C. Lee, W. W. MacKay, G. J. Marr, R. J. Michnoff, B. Oerter, E. Pozdeyev, T. Roser, F. Severino, K. Smith, S. Tepikian, N. Tsoupas
  BNL, Upton, Long Island, New York

There is significant interest in RHIC heavy ion collisions at c.m. energies of 5-50 GeV/u, motivated by a search for the QCD phase transition critical point. The low end of this energy range is well below the nominal RHIC injection c.m. energy of 19.6 GeV/u. There are several challenges that face RHIC operations in this regime, including longitudinal acceptance, magnet field quality, lattice control, and luminosity monitoring. We report on the status of work to address these challenges and include results from beam tests of low-energy RHIC operations with protons and gold.

• T. M. Himel
  
• J. Nelson, N. Phinney
  SLAC, Menlo Park, California
• M. C. Ross
  Fermilab, Batavia, Illinois

The International Linear Collider will be the largest most complicated accelerator ever built. For this reason extensive work is being done early in the design phase to ensure that it will be reliable enough. This includes gathering failure mode data from existing accelerators and simulating the failures and repair times of the ILC. This simulation has been written in a general fashion using MATLAB and could be used for other accelerators. Results from the simulation tool have been used in making some of the major ILC design decisions and an unavailability budget has been developed.

• V. Vogel
  
• A. Cherepenko
  BINP SB RAS, Novosibirsk
• S. Choroba, T. Froelich, T. G. Grevsmuehl, F.-R. Kaiser, V. V. Katalev, I. S. Sokolov, H. Timm
  DESY, Hamburg

• A. Fabris
  
• M. Bocciai, C. Pasotti, M. Rinaldi
  ELETTRA, Basovizza, Trieste

• K. Shirasawa
  
• H. Baba, H. Matsumoto
  KEK, Ibaraki
• T. Inagaki, H. Kitamura, T. Shintake
  RIKEN Spring-8 Harima, Hyogo
• S. Miura
  MHI, Hiroshima

• L. Shen
  
• Y. L. Chi, C. Huang
  IHEP Beijing, Beijing

• J. Alex
  
• M. Bader, J. Troxler
  Thomson Broadcast & Multimedia AG, Turgi

Thomson Broadcast & Multimedia has been awarded a contract from DESY to design and build a prototype klystron modulator for the XFEL project. This modulator will be built in pulse step modulator (PSM) technology. This technology will allow to control the pulse form to achieve a maximum flatness of the pulse without tuning any high power components. The modulator will also have a built-in power regulation to prevent voltage flicker of the mains. The paper will give an overview about the principles of the modulator and presents the status of the design. It also shows simulation results about the expected performance.

• D. Cook
  
• J. Clare, P. W. Wheeler
  University of Nottingham, Nottingham
• J. S. Przybyla
  e2v, Essex

• M. A. Kempkes
  
• M. P.J. Gaudreau, I. Roth, R. P. Torti
  Diversified Technologies, Inc., Bedford, Massachusetts

• M. A. Kempkes
  
• M. P.J. Gaudreau, J. Kinross-Wright, I. Roth
  Diversified Technologies, Inc., Bedford, Massachusetts

• K. M. Baptiste
  
• P. W. Casey, S. Kwiatkowski, CA. Timossi
  LBNL, Berkeley, California

ALS, one of the first third generation synchrotron light sources which has been operating since 1992 at Berkeley Lab has been upgraded from its present operation scenario of injecting the 1.5GeV electron beam from the Booster ring into the Storage ring every 8 hours where it is accelerated to the final energy of 1.9GeV to full energy (1.9GeV) injection from the Booster ring into the Storage ring every 3 seconds for filling and every 30-35 seconds for Top-Off mode. Additionally the beam current has been increased from the time averaged value of 250mA to 500mA to increase the brightness. In this paper we will present the results of the new ALS injector RF system set-up for Top-Off mode of operation, the final design and operational results of the Booster RF power source and control system upgrades.

• A. V. Morgan
  
• H. Padamsee
  Cornell University, Ithaca, New York
• A. Romanenko, A. J. Windsor
  CLASSE, Ithaca

Electropolishing is now the preferred method for chemical treatment of niobium cavity surfaces. It provides a very smooth surface and after baking accelerating fields between 35 - 40 MV/m. However the reproducibility of performance needs to be improved substantially. Some of the leading causes are related to contaminant residues after electropolishing, these include sulphur particles, niobium pentoxide particles and traces of aluminum from reaction between the aluminum cathode and the acid electrolyte. We have carried out studies to enhance the deposition of such particles so that we can isolate and study the residues. We will present analysis of these studies using optical microscopy, SEM, and Auger. In at attempt to dissolve these contaminants, we have also conducted studies on the effectiveness of various rinsing agents, such as degreasing agents, dilute HF, hydrogen peroxide.

• J. T.M. Lyles
  
• S. Archuletta, D. Baca, J. Davis, D. Rees, P. A. Torrez
  LANL, Los Alamos, New Mexico

A new 200 MHz RF system is being developed for the LANSCE proton drift tube linac (DTL). A planned upgrade will replace parts of the DTL RF system with new generation components. When installed for the LANSCE-R project, the new system will reduce the total number of electron power tubes from twenty-four to seven in the DTL plant. The 3.4 MW final power amplifier will use a Thales TH628 Diacrode. This state-of-the-art device eliminates the large anode modulator of the present triode system, and will be driven by a new tetrode intermediate power amplifier. In this mode of operation, this intermediate stage will provide 150 kW of peak power. The first DTL tank requires up to 400 kW of RF power, which will be provided by the same tetrode driver amplifier. A prototype system is being constructed to test components, using some of the infrastructure from previous RF projects. High voltage DC power became available through innovative re-engineering of an installed system. A summary of the design and construction of the intermediate power amplifier will be presented and test results will be summarized.

• W. Reass
  
• V. P. Derenchuk, T. Rinckel, G. Visser
  IUCF, Bloomington, Indiana
• D. Rees
  LANL, Los Alamos, New Mexico

This paper describes the Klystron RF systems for the Indiana University Low Energy Neutron Source (LENS) accelerator 425 MHz Radio Frequency Quadrupole (RFQ) and Drift Tube Linac (DTL) systems. Of interest in the power conditioning system is the design of the totem-pole grid-catch modulator for the mod-anode klystrons. This topology provides a fast rise and fall and closed loop regulation for the klystron mod-anode to cathode voltage, which minimizes RF amplitude and phase droop while maximizing efficiency. Another advantage is that short pulse high rep-rate operation is viable within the average power capabilities of the klystron. The 425 MHz, 1.25 MW klystron amplifier chain will also be detailed. Of final interest, is the digital low level RF system. This provides vector control of the cavity field using direct conversion, non-I/Q sampling architecture, at a sampling rate of 132 MHz with a 12-bit ADC. Four input and two output channels are integrated into a 6U VME module, with all DSP functions performed in Xilinx Spartan-3 field-programmable gate arrays. The design and implementation of these systems, coupled with LENS operational results, will be presented.

• D. Rees
  
• G. O. Bolme, J. T. Bradley III, S. Kwon, J. T.M. Lyles, M. T. Lynch, M. S. Prokop, W. Reass, K. A. Young
  LANL, Los Alamos, New Mexico

• M. N. Nguyen
  
• R. L. Cassel
  SLAC, Menlo Park, California

A compact, water cooled, high power switch for the Superconducting Module Test Facility (SMTF) long-pulse klystron modulator has been designed and implemented at the Fermi National Accelerator Laboratory (FNAL). This solid-state switch is composed of six series devices, each having a rating of 4.5 kV at 2000 Adc. Latest generation, press-pack IGBT modules are utilized to reduce the physical size and complexity of the switch assembly. The new switch and its associated controller provide a high degree of redundancy and fail-safe operation, which meets the modulator requirements. This paper describes the general switch assembly, IGBT protection and control schemes, and test results.

• J. J. Mize, J. J. Mize
  ORNL, Oak Ridge, Tennessee

The high frequency switching megawatt-class High Voltage Converter Modulator (HVCM) developed by Los Alamos National Laboratory for the Oak Ridge National Laboratory's Spallation Neutron Source (SNS), is now in operation. One of the major problems with the modulator systems is shoot-thru conditions that can occur in an IGBTs H-bridge topology resulting in large fault currents and device failure in a few microseconds. The Dynamic Fault Detection Chassis (DFDC) is a fault monitoring system; it monitors transformer flux saturation using a window comparator and dV/dt events on the cathode voltage caused by any abnormality such as capacitor breakdown, transformer primary turns shorts, or dielectric breakdown between the transformer primary and secondary. If faults are detected, the DFDC will inhibit the IGBT gate drives and shut the system down, significantly reducing the possibility of a shoot-thru condition or other equipment damaging events. In this paper,we will present system integration considerations, performance characteristics of the DFDC, and discuss its ability to significantly reduce costly down time for the entire facility.

• M. A. Kempkes
  
• F. O. Arntz, J. A. Casey, M. P.J. Gaudreau, I. Roth
  Diversified Technologies, Inc., Bedford, Massachusetts

• T. Semba
  
• Y. Chida, Y. Itou, T. Tagawa, Y. Tsujioka, T. Yoshinari
  Hitachi Ltd., Ibaraki-ken
• N. Shibata
  Hitachi High-Technologies Corp., Ibaraki-ken

• H. Mori
  
• M. Akemoto, S. Fukuda, H. Honma, H. Nakajima, T. Shidara
  KEK, Ibaraki
• K. Furuya
  Nichicon (Kusatsu) Corporation, Shiga

• T. Inagaki
  
• H. Baba, H. Matsumoto
  KEK, Ibaraki
• A. Miura
  Nihon Koshuha Co., Ltd., Yokohama
• S. Miura
  MHI, Hiroshima
• T. Shintake, K. Shirasawa
  RIKEN Spring-8 Harima, Hyogo

C-band (5712-MHz) linac is used as the main accelerator of the Japanese X-FEL facility in SPring-8. Since the C-band linac has high acceleration gradient, our 8-GeV accelerator is compact rather than a conventional S-band accelerator. The system consists of following components; two choke-mode-type 1.8-m accelerating structures, an rf pulse compressor (SLED), a 50-MW klystron, a 100-MW compact modulator, and an rf digital control system. We will use 60 to 70 units for the X-FEL accelerator. Since November 2005, we have operated two C-band units in the 250-MeV FEL prototype accelerator (SCSS). After rf conditioning, the accelerating gradient was achieved to 35-MV/m. We successfully accelerated the electron beam by this gradient of electrical field. In this presentation, we will report the detail of each component and its operation status of the SCSS prototype accelerator.

• T. Naito
  
• H. Hayano, K. Kubo, M. Kuriki, N. Terunuma, J. Urakawa
  KEK, Ibaraki

• T. Natsui
  
• M. Akemoto, S. Fukuda, T. Higo, N. Kudoh, T. T. Takatomi, M. Yoshida
  KEK, Ibaraki
• K. Dobashi, M. Uesaka, T. Yamamoto
  UTNL, Ibaraki
• F. Sakamoto, A. Sakumi
  The University of Tokyo, Nuclear Professional School, Ibaraki-ken
• E. Tanabe
  AET Japan, Inc., Kawasaki-City

• S. H. Kim
  
• M.-H. Cho, W. Namkung, H. R. Yang
  POSTECH, Pohang, Kyungbuk
• S. D. Jang, S. J. Kwon, J.-S. Oh, S. J. Park, Y. G. Son
  PAL, Pohang, Kyungbuk

An intense L-band electron accelerator is designed and under development for CESC (Cheorwon Electron-beam Service Center) irradiation applications. It is capable of producing 10-MeV electron beams with average 30 kW. For an RF source, a Thales klystron is used with 1.3 GHz, pulsed 25 MW, and average 60 kW. The accelerator column, fabricated by IHEP in China, is operated with 2π/3 mode traveling-wave under the fully-beam-loaded condition. The modulator was fabricated with inverter power supplies. The klystron was assembled to the klystron tank with pulse transformer. The high-voltage pulse test was conducted for the klystron tube. In this paper, we present design details of the accelerator and current status.

• H. Wang
  
• W. Gai, W. Liu
  ANL, Argonne, Illinois
• A. Kanareykin
  Euclid TechLabs, LLC, Solon, Ohio
• T. Wong
  Illinois Institute of Technology, Chicago, Illinois

* H. Brechna, D. A. Hill and B. M. Bally, "150 KOe Liquid Nitrogen Cooled Flux Concentrator Magnet", Rev. Sci. Instr., 36 1529,1965.

• I. V. Bylinskii
  
• K. Fong, J. Lu, A. K. Mitra, C. Owen
  TRIUMF, Vancouver

• C. H. Kuo
  
• J. Chen, P. C. Chiu, K. T. Hsu, K. H. Hu
  NSRRC, Hsinchu

• A. Pietryla
  
• H. Bui, G. Decker, R. Laird, R. M. Lill, W. E. Norum
  ANL, Argonne, Illinois

The Advanced Photon Source (APS), a third-generation synchrotron light source, has been in operation for twelve years. The monopulse radio frequency (rf) beam position monitor (BPM) is one of three BPM types now employed in the storage ring at the APS. It is a broadband (10 MHz) system designed to measure single-turn and multi-turn beam positions, but it suffers from an aging data acquisition system. The replacement BPM system retains the existing monopulse receivers and replaces the data acquisition system with high-speed analog-to-digital converters (ADCs) and a field-programmable gate array (FPGA) that performs the signal processing. A first article system has been constructed and is currently being evaluated. This paper presents the results of testing of the first article system as well as the progress made in other areas of this upgrade effort.

• J. M. Weber
  
• M. J. Chin, CA. Timossi, E. C. Williams
  LBNL, Berkeley, California

The ALS booster magnet upgrade for top off operation requires new instrumentation to meet increased magnet ramping requirements. To address these requirements, the ALS Instrumentation and Controls groups collaborated to design a new control system module called the Mini IOC. The Mini IOC hardware is based on a commercial evaluation board containing an FPGA with embedded processor and built-in interfaces for 128MB of DDR SDRAM and Ethernet. A custom module is used for analog controls and monitors. The PowerPC embedded processor runs an EPICS database built on the VxWorks operating system allowing remote access via Ethernet. This paper includes an overview of the Mini IOC design and operational results.