A   B   C   D   E   F   G   H   I   K   L   M   O   P   Q   R   S   T   U   V   W  

monitoring

Paper Title Other Keywords Page
MOPAN019 Performance of the New Master Oscillator and Phase Reference System at FLASH controls, linac, free-electron-laser, klystron 188
 
  • S. Simrock
  • K. C. Czuba
    Warsaw University of Technology, Institute of Electronic Systems, Warsaw
  • M. F. Felber, M. Hoffmann, B. Lorbeer, F. Ludwig, H. C. Weddig
    DESY, Hamburg
  The master oscillator and phase reference system at FLASH must provide several rf reference frequencies to widely spread locations with low phase noise and small long term phase drifts. The phase noise requirements of the 1300 MHz reference is of the order of 0.1 deg. while short and medium term phase stability is of of the order of 0.1 deg. and 1 deg. respectively. The frequency distribution system employs a temperature stabilized coaxial line for rf power distribution and a fiber optic system for the monitoring of phase drifts. Presented are the the concept, design and performance measured in the accelerator environment.  
 
MOPAN058 Control System for PEFP Instruments with Modbus Protocol controls, power-supply, proton, electron 284
 
  • I.-S. Hong
  • Y.-G. Song
    KAERI, Daejon
  Funding: This work was supported by the 21C Frontier R&D program sponsored by Ministry of Science and Technology, Korean Government.

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.

 
 
MOPAN059 PEFP Monitoring System Through an Analog Input to Ethernet Converter power-supply, controls, proton, linac 287
 
  • Y.-G. Song
  • Y.-S. Cho, I.-S. Hong
    KAERI, Daejon
  Funding: This work was supported by the 21C Frontier R&D program sponsored by Ministry of Science and Technology, Korean Government.

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.

 
 
MOPAN070 Developments in High-precision Aspects of Power Converter Control for LHC controls, shielding, target, diagnostics 314
 
  • G. Fernqvist
  • M. C. Bastos, A. Cantone, Q. King
    CERN, Geneva
  The initial results from integration testing of the LHC magnet power converters revealed problems of low-frequency noise, settling time, drift with time and temperature, thermal management and EMC. These problems originated in the use of DSP, the A/D converter (ADC), the DC Current Transducer (DCCT) and their respective environments. This paper reports the methods used to improve the performance through hardware and software modifications and the results achieved.  
 
MOPAN072 High-precision Performance Testing of the LHC Power Converters controls, factory, instrumentation, collider 320
 
  • G. Fernqvist
  • M. C. Bastos, A. Cantone, P. Dreesen, O. Fournier, G. Hudson
    CERN, Geneva
  The magnet power converters for LHC were procured in three parts, power part, current transducers and control electronics, to enable a maximum of industrial participation in the manufacturing and still guarantee the very high precision (a few parts in 10-6) required by LHC. One consequence of this approach was several stages of system tests: factory reception tests, CERN reception tests, integration tests, short-circuit tests and commissioning on the final load in the LHC tunnel. The majority of the power converters for LHC have now been delivered, integrated into complete converters and high-precision performance testing is well advanced. This paper presents the techniques used for high-precision testing and the results obtained. It is also hoped to report results from the first sector commissioning.  
 
MOPAN075 Experimental Modal Analysis of Components of the LHC Experiments damping, acceleration, resonance, coupling 329
 
  • M. Guinchard
  • K. Artoos, A. Catinaccio, K. Kershaw, A. Onnela
    CERN, Geneva
  Experimental modal analysis of components of the LHC Experiments is performed with the purpose of determining their fundamental frequencies, their damping and the mode shapes of light and fragile detectors components. This process permits to confirm or replace Finite Element analysis in the case of complex structure (with cables and substructure coupling). It helps solving structural mechanics problems to improve the operational stability and determine the acceleration specifications for transport operations. This paper describes the hardware and software equipments used to perform a modal analysis on particular structures such as a particle detectors and the method of curve fitting to extract the results of the measurements. This paper exposes also the main results obtained for the LHC Experiments.  
 
MOPAN076 Remote Inspection, Measurement and Handling for LHC controls, radiation, survey, alignment 332
 
  • K. Kershaw
  • F. Chapron, A. Y. Coin, F. Delsaux, T. Feniet, J. L. Grenard, R. V. Valbuena
    CERN, Geneva
  Personnel access to the LHC tunnel will be restricted to varying extents during the life of the machine due to radiation, cryogenic and pressure hazards. The ability to carry out visual inspection, measurement and handling activities remotely during periods when the LHC tunnel is potentially hazardous offers advantages in terms of safety, accelerator down time, and costs. The first applications identified were remote measurement of radiation levels at the start of shut-down, remote geometrical survey measurements in the collimation regions, and remote visual inspection during pressure testing and initial machine cool-down. In addition, for remote handling operations, it will be necessary to be able to transmit several real-time video images from the tunnel to the control room. The paper describes the design, development and use of a remotely controlled vehicle to demonstrate the feasibility of meeting the above requirements in the LHC tunnel. Design choices are explained along with operating experience to-date and future development plans.  
 
MOPAN099 Integrated Mechanism of Online Monitor and Archive System controls, instrumentation, synchrotron, synchrotron-radiation 392
 
  • Z.-D. Tsai
  • J.-C. Chang, T.-S. Ueng
    NSRRC, Hsinchu
  In the accelerator field, the instrumentation monitor system provides the machine online status to view, control and alert. A novel shared data engine developed by Labview provides the distributed PCs, PDAs, embedded devices, and local controllers to exchange data mutually via Ethernet or wireless Ethernet. The mechanism guarantees delivery with an additional function layer of the raw UDP protocol and usees less network bandwidth than TCP/IP. The system's main function is to introduce a platform with reliable online information about the status of the instrumentation. The users can access data with graphic view and trend view by some complementary software. Also, the users can easily take the online data via binding monitor tags without programming. The mechanism benefits all system maintenance, operation, management and analysis.  
 
MOPAN102 SMS Alert System at NSRRC controls, instrumentation, site 401
 
  • T.-S. Ueng
  • J.-C. Chang, Z.-D. Tsai
    NSRRC, Hsinchu
  SMS (Short Message Service) technology has been used extensively today in the wireless world. The Utility Group at NSRRC has developed an SMS alert and notification system with LabVIEW programming language to continuously monitor the critical signals of its utility systems. A short message will be sent immediately to the responsible people in case of critical components failure. Many critical signals in the Instrumentation Division have also been included in this system for monitoring. Since its implementation the maintenance people have been notified many times to restore the faulty system to prevent accelerator from being shutdown or to minimize the damage. The detailed methodology used will be presented here.  
 
MOPAN104 Current Monitor for the ISIS Synchrotron RF Cavity Bias Regulator controls, synchrotron, lattice, acceleration 407
 
  • A. Daly
  • C. W. Appelbee, D. Bayley
    STFC/RAL/ISIS, Chilton, Didcot, Oxon
  The ISIS facility at the Rutherford Appleton Laboratory in the UK is currently the world's most intense pulsed neutron source. The accelerator consists of a 70 MeV H- Linac and an 800 MeV, 50 Hz, proton Synchrotron. The synchrotron beam is accelerated using six, ferrite loaded, RF cavities each having its own high voltage r.f. drive amplifier and bias system. Each of these cavities is driven as a high Q tuned r.f. circuit; the resonant frequency being controlled by passing a current through a bias winding. This current comes from the Bias Regulator system which consists in part of eight banks of 40 transistors. This paper describes the design of a system which will use digital techniques to monitor and display the current of each of the 320 transistors in the Bias Regulator system.  
 
MOPAN112 Digital Control Interface for Bipolar Corrector Power Supplies for LCLS controls, power-supply, feedback, diagnostics 428
 
  • S. Cohen
  • S. R. Babel
    Bira, Albuquerque, New Mexico
  We detail the development, testing and commissioning of a single-board digital interface for modular bipolar corrector magnet power supplies to installed at the Linac Coherent Light Source (LCLS) at the Stanford Linear Accelerator (SLAC). The sixteen-channel VME-form-factor board replaces the passive the control-interface board in the MCOR (Magnet Corrector) Chassis. The board is a self-contained system with both serial and Ethernet connectivity intended for use with an EPICS accelerator control system IOC, however, the ASCII protocol allows generic computer control. The interface card contains 16 independent ADC and DAC channels, each with 16 bits of resolution. Additionally, the interlock, fault, reset and digital control lines are remotely controllable via either the serial or Ethernet connections. The design has been planned so that a mini-IOC can be included on board for direct Channel Access connectivity.  
 
MOPAN113 The P0 Feedback Control System Blurs the Line between IOC and FPGA feedback, controls, photon, storage-ring 431
 
  • N. P. Di Monte
  Funding: Work supported by U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.

The P0 Feedback System is a new design at the APS with the main intent to stabilize a single bunch in order to operate at a higher accumulated charge. The algorithm for this project required a high-speed DSP solution for a single channel that would make adjustments on a turn-by-turn basis. An FPGA solution was selected that not only met the requirements of the project, but far exceeded the requirements. By using a single FPGA, we were able to adjust up to 324 bunches on two separate channels with a total computational time of ~6x109 multiply-accumulate operations per second. The IOC is a Coldfire CPU tightly coupled to the FPGA, providing a dedicated control and monitoring of the system through EPICS process variables. One of the benefits of this configuration is having a four-channel scope in the FPGA that can be monitored on a continuous basis.

 
 
MOPAS005 System Overview for the Multi-element Corrector Magnets and Controls for the Fermilab Booster power-supply, booster, controls, acceleration 449
 
  • 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
  Funding: Work supported by the U. S. Department of Energy

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.

 
 
MOPAS043 Instrumentation for the Cornell ERL Injector Test Cryostats controls, cryogenics, vacuum, instrumentation 527
 
  • P. Quigley
  • S. A. Belomestnykh, M. Liepe, V. Medjidzade, J. Sears, V. Veshcherevich
    CLASSE, Ithaca
  Funding: Work is supported by the National Science Foundation grant PHY 0131508

Cornell is building a 1.3 GHz Injector Cryomodule for an ERL prototype. The cryomodule consists of five two-cell niobium cavities each cavity having two coaxial power input couplers. Cavity and coupler pairs will require acceptance testing at high power prior to assembly in the injector cryomodule. A liquid nitrogen cryostat for testing the couplers at high power has been built and the first input coupler test is complete. In addition, a Horizontal Test Cryostat (HTC) is being built to test input coupler pairs and cavities as a set. The first HTC test is scheduled for spring 2007. Details for instrumentation of the Coupler Test Cryostat (CTC) and HTC are presented.

 
 
MOPAS052 The LANSCE Control System Current State and Upgrade Outlook controls, linac, instrumentation, diagnostics 554
 
  • M. Pieck
  • E. Bjorklund, G. P. Carr, J. A. Faucett, J. O. Hill, D. M. Kerstiens, P. S. Marroquin, P. McGhee, M. A. Oothoudt, S. Schaller
    LANL, Los Alamos, New Mexico
  The LANSCE (Los Alamos Neutron Science Center) runs its LINAC control system based on 30(+) year old technology. While some peripheral upgrades have been made over the years, the control system will need some major improvements over the next five years in order to continue to support the user facility's mission. The proposed multi-million dollar LANSCE-R (Refurbishment) project creates a unique opportunity to upgrade the existing control system. We intend to use the EPICS (Experimental Physics and Industrial Control System) control system with the following goals for effective control at modest cost: (1) Replacing our VMS basedμVAX's; (2) Replacing the RICE (Remote Instrumentation and Control Equipment) subsystem with Programmable Logic Controllers (PLCs) to handle regular data acquisition and control, and custom hardware to handle "flavored" data acquisition; (3) Replacing the Master Timer subsystem with a modern event system; (4) Converting Fortran programs running on VAX/VMS computers to Java Programs running on Linux-based desktop PCs. The boundary condition, as usual, is that we must implement these major changes on a running accelerator.  
 
MOPAS085 The SNS Insulating Vacuum Design for the Superconducting Linac vacuum, controls, linac, radiation 629
 
  • D. C. Williams
  • X. Geng, P. Ladd
    ORNL, Oak Ridge, Tennessee
  Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U. S. Department of Energy

The superconducting linac of the Spallation Neutron Source (SNS) has 23 cryomodules each of which incorporate either 3 or 4 niobium cavities. These cavities are submerged in a bath of liquid helium and maintained at an operating temperature of ~ 2K. This bath is surrounded by heat shields and a multilayer blanket within the cryomodule shell. The pressure in this area needs to be maintained at <5·10-5 torr to limit heat leak due to gas convection. Some cryomodules have developed helium leaks into this vacuum cavity and now need to be actively pumped. This paper provides an overview of the Insulating Vacuum System (IVS) that has been installed for this purpose.

 
 
TUZAC01 The ILC Control System Design controls, feedback, linac, linear-collider 868
 
  • J. Carwardine
  • N. D. Arnold, F. Lenkszus, C. W. Saunders
    ANL, Argonne, Illinois
  • B. Banerjee, B. Chase, E. G. Gottschalk, P. W. Joireman, P. A. Kasley, J. R. Lackey, P. M. McBride, J. F. Patrick, V. Pavlicek, M. Votava, S. A. Wolbers
    Fermilab, Batavia, Illinois
  • R. W. Downing, R. S. Larsen
    SLAC, Menlo Park, California
  • K. Furukawa, S. Michizono
    KEK, Ibaraki
  • K. Rehlich, S. Simrock
    DESY, Hamburg
  Funding: Work supported in the U. S. by the U. S. Department of Energy under contract Nos. DE-AC02-06CH11357, DE-AC02-76CH03000, and DE-AC02-76SF00515.

The scale and performance parameters of the ILC require new thinking in regards to control system design. This design work has begun quite early in comparison to most accelerator projects, with the goal of uniquely high overall accelerator availability. Among the design challenges are high control system availability, timing reference distribution, standardization of interfaces, operability, and maintainability. We present the current state of the design and take a prospective look at ongoing research and development projects.

 
slides icon Slides  
 
TUPMN076 The Fabrication and Characterization of an S-band RF-gun Cavity coupling, impedance, gun, resonance 1097
 
  • T.-T. Yang
  • C.-S. Fann, K. T. Hsu, S. Y. Hsu, J.-Y. Hwang, W. K. Lau, A. P. Lee, C. C. Liang, K.-K. Lin, K.-B. Liu, Y.-C. Liu, H. M. Shih, M.-S. Yeh
    NSRRC, Hsinchu
  A single cell rf-gun cavity is designed and fabricated for the purpose of examining the feasibility of installing a thermionic rf-gun at NSRRC instead of a photocathode rf-gun considered previously. The operating frequency of the rf-gun cavity is set at 2856 MHz in order to utilize the available XK-5 klystron and linac. The fabricated parts of the OFHC copper cavity are brazed together in-house and then the cavity is characterized by rf measurement. It shows that the cavity gives very good character in terms of high quality factor, relaxed tuning range, adequate coupling coefficient, and reasonable reproducibility. The properties of the cavity are further explored by measuring the field profile and its response to an rf pulse in which the filling time is deduced. The measurement results of this brazed cavity are described and summarized in this report.  
 
TUPAN043 RF Amplitude and Phase Tuning of J-PARC DTL linac, beam-transport, injection, controls 1481
 
  • M. Ikegami
  • H. Asano, T. Kobayashi
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  • K. Hasegawa, T. Ito, T. Morishita, S. Sato, A. Ueno
    JAEA/LINAC, Ibaraki-ken
  • Z. Igarashi, H. Tanaka
    KEK, Ibaraki
  • H. Sako
    JAEA, Ibaraki-ken
  The beam commissioning of J-PARC linac has been started in November 2006. In the beam commissioning, the tuning of the RF phase and amplitude for its DTL (Drift Tube Linac) has been performed with a phase-scan method. Detailed results of the RF tuning are presented with a brief discription of the tuning procedure.  
 
TUPAS068 A Transverse Beam Instability in the PEP-II HER Induced by Discharges in the Vacuum System vacuum, coupling, background, betatron 1811
 
  • U. Wienands
  • W. S. Colocho, S. DeBarger, F.-J. Decker, S. Ecklund, A. S. Fisher, J. D. Fox, A. Kulikov, A. Novokhatski, M. Stanek, M. K. Sullivan, W. Wittmer, D. Wright, G. Yocky
    SLAC, Menlo Park, California
  Funding: Work supported by US Dept. of Energy

During Run 5, PEP-II has been plagued by beam instabilities causing beam aborts due to radiation in the BaBar detector or due to fast beam loss triggering the dI/dt interlock. The latest of such instabilities occurred in the High Energy Ring (HER), severely curtailing the maximum beam current achievable during physics running. Techniques used in tracking down this instability included fast monitoring of background radiation, temperatures and vacuum pressure. In this way, the origin of the instability was localized and inspection of the vacuum system revealed several damaged bellows shields. Replacing these units significantly reduced the incident rate but did not eliminate it fully. After the end of the run, a number of damaged rf seals were found, possibly having caused the remaining incidents of instability. In this paper we will outline the steps taken to diagnose and remedy the issue and also compare the different signatures of vacuum-induced instabilities we have seen in both rings of PEP-II during the run.

 
 
WEPMN096 Status of the 3.9-GHz Superconducting RF Cavity Technology at Fermilab superconducting-RF, controls, vacuum, cryogenics 2254
 
  • E. R. Harms
  • T. T. Arkan, L. Bellantoni, H. Carter, H. Edwards, M. Foley, T. N. Khabiboulline, D. V. Mitchell, D. R. Olis, A. M. Rowe, N. Solyak
    Fermilab, Batavia, Illinois
  Funding: This work supported by Universities Research Association Inc. under contract DE-AC02-76CH00300 with the U. S. DOE.

Fermilab is involved in an effort to assemble 3.9 GHz superconducting RF cavities into a four cavity cryomodule for use at the DESY TTF/FLASH facility as a third harmonic structure. The design gradient of these cavities is 14 MV/m limited by thermal heat transfer. This effort involves design, fabrication, intermediate testing, assembly, and eventual delivery of the cryomodule. We report on all facets of this enterprise from design through future plans. Included will be test results of single 9-cell cavities, lessons learned, and current status.

 
 
WEPMN103 Mechanical Stability Study of Capture Cavity II at Fermilab vacuum, resonance, cryogenics, superconducting-RF 2274
 
  • M. McGee
  • Y. M. Pischalnikov
    Fermilab, Batavia, Illinois
  Problematic resonant conditions at both 18 Hz and 180 Hz were encountered and identified early during the commissioning of Capture Cavity II (CC2) at Fermilab. CC2 consists of an external vacuum vessel and a superconducting high gradient (close to 25 MV/m) 9-cell 1.3 GHz niobium cavity, transported from DESY for use in the A0 Photoinjector at Fermilab. An ANSYS modal finite element analysis (FEA) was performed in order to isolate the source of the resonance and directed the effort towards stabilization. A novel idea was implemented, by using a fast piezoelectric tuner to excite (or shake) the cavity at different frequencies (from 10 Hz to 200 Hz) as a low-range sweep for analysis purposes. Both warm (300 K) and cold (1.8 K) accelerometer measurements at the cavity were taken as the resonant 'fix' was applied. FEA results, cultural and technical noise investigation, and stabilization techniques are discussed.

Operated by Universities Research Association, Inc., under Contract No. DE-AC02-76CH03000 with the U. S. Department of Energy#mcgee@fnal.gov

 
 
WEPMN108 A Technique for Monitoring Fast Tuner Piezoactuator Preload Forces for Superconducting RF Cavities instrumentation, resonance, controls, simulation 2289
 
  • Y. M. Pischalnikov
  • J. Branlard, R. H. Carcagno, B. Chase, H. Edwards, A. Makulski, M. McGee, R. Nehring, D. F. Orris, V. Poloubotko, C. Sylvester, S. Tariq
    Fermilab, Batavia, Illinois
  Funding: Work supported by Universities Research Association Inc. under Contract No. DE-AC02-76CH03000 with the United States Department of Energy.

The technology for mechanically compensating Lorentz Force detuning in superconducting RF cavities has already been developed at DESY. One technique is based on commercial piezoelectric actuators and was successfully demonstrated on TESLA cavities*. Piezo actuators for fast tuners can operate in a frequency range up to several kHz; however, it is very important to maintain a constant preload force on the piezo stack in the range of 10 to 50% of its specified blocking force. Determining the preload force during cooldown, warm-up, or re-tuning of the cavity is difficult without instrumentation, and exceeding the specified range can permanently damage the piezo stack. A technique based on strain gauge technology for superconducting magnets has been applied to fast tuners for monitoring the preload on the piezoelectric assembly. This paper will address the design and testing of piezo actuator preload sensor technology. Results from measurements of preload sensors installed on the tuner of the DESY Capture Cavity II tested at Fermilab will be presented. These results include measurements during cooldown, warm-up, and cavity tuning along with dynamic Lorentz force compensation.

* M. Liepe et al," Dynamic Lorentz Force Compensation with a Fast Piezoelectric Tuner" PAC2001

 
 
WEPMS018 Superconducting Materials Testing with a High-Q Copper RF Cavity klystron, cryogenics, superconductivity, feedback 2370
 
  • A. Canabal
  • G. B. Bowden, V. A. Dolgashev, J. R. Lewandowski, C. D. Nantista, S. G. Tantawi
    SLAC, Menlo Park, California
  • I. E. Campisi
    ORNL, Oak Ridge, Tennessee
  • T. Tajima
    LANL, Los Alamos, New Mexico
  Magnesium diboride (MgB2) has a transition temperature (Tc) of ~40 K, i.e., about 4 times higher than niobium (Nb) that has been used for recent accelerators. The studies in the last 3 years have shown that it could have about one order of magnitude less RF surface resistance (Rs) than Nb and much less power dependence compared to high-Tc materials such as YBCO up to ~400 Oe. The tests to check the RF critical magnetic field, an important parameter to determine the feasibility for accelerator application, are underway. We are planning to test different thickness films and with different coating methods. This paper describes the results obtained so far. One of the objectives is to verify Gurevich's theory of getting higher critical field than Nb by adding a very thin layer (less than penetration depth) to Nb. In addition, some CW tests on power dependence up to higher magnetic fields are planned and some results will be shown if available at the time of conference.  
 
WEPMS025 LANSCE-R Low Level RF Control System controls, resonance, feedback, beam-loading 2388
 
  • M. S. Prokop
  • S. Kwon, S. Ruggles, P. A. Torrez
    LANL, Los Alamos, New Mexico
  The Los Alamos Neutron Science Center proton accelerator is scheduled for refurbishment. A new low level RF(LLRF) system is part of the refurbishment plan since the existing LLRF system is analog-based and requires significant setup and maintenance time. Both field and resonance control aspects of the current system do not have the flexibility to meet future performance requirements. The LANSCE accelerator provides both H+ and H- beams and due to the various user requirements there are a number of different beam pulse types varying in timing and current. In order to meet user needs, LANSCE must simultaneously transport both H+ and H- in the accelerator. These requirements have motivated the development of a new LLRF system based on software defined radio technology. The new system will include field control using feedback and adaptive feed forward techniques, an upgraded resonance controller with frequency agility to improve startup and fault recovery times and a high power amplifier pre-compensation controller for improved cavity fill times and amplifier efficiency. Among the challenges with implementing the new system are interfacing with existing subsystems of the accelerator.  
 
WEPMS030 Design and Initial Testing of Omniguide Traveling-wave Tube Structures electron, vacuum, coupling, higher-order-mode 2403
 
  • E. I. Smirnova
  • B. E. Carlsten, L. M. Earley, W. B. Haynes
    LANL, Los Alamos, New Mexico
  Funding: This work was funded in part by the LDRD Director's Postdoctoral Fellowship, Los Alamos National Laboratory.

We propose to use the photonic band gap (PBG) structures for the construction of a traveling-wave tube (TWT) at W-band. Interest in millimeter-waves has increased in recent years due to applications in environmental monitoring and remote sensing. The development of wide-band mm-wave TWT amplifiers is underway at Los Alamos National Laboratory. A TWT would present a wide bandwidth source for remote mm-wave spectroscopy. PBG TWT structures have great potential for very large bandwidth and linear dispersion. In addition, being cheap to fabricate, the PBG structures enhance the commercial transferability of the W-band TWT technology. We employ an omniguide which is a one-dimensional version of the PBG structure representing a periodic system of concentric dielectric tubes as a slow-wave structure. A silica omniguide was designed to support a TM01-like mode with a phase velocity matching the one of a 120keV electron beam. The structure was fabricated, cold-tested and installed at our laboratory for the hot test.

 
 
WEPMS044 High Power Switch for the SMTF Modulator controls, klystron, power-supply, superconducting-RF 2445
 
  • M. N. Nguyen
  • R. L. Cassel
    SLAC, Menlo Park, California
  Funding: Work supported by the Department of Energy under contract No. DE-AC03-76SF00515.

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.

 
 
WEPMS079 Dynamic Fault Detection Chassis for the 1 MW High Voltage Converter Modulator System at the Spallation Neutron Source controls, power-supply, cathode, klystron 2514
 
  • J. J. Mize, J. J. Mize
    ORNL, Oak Ridge, Tennessee
  Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U. S. Department of Energy.

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.

 
 
THXC02 Diagnostics for Commissioning LCLS emittance, diagnostics, linac, radiation 2635
 
  • P. Krejcik
  The fist stage of commissioning of the Linac Coherent Light Source at SLAC has begun in April of this year with succesful transport of the beam from the new RF photoinjector throught to the first bunch compressor. Construction and installation is continuing and will culminate with first FEL light in 2009. The LCLS provides several diagnostic challenges for providing precision, single-pulse readback of beam size and position in order to tune for very low 1 micron emittances. Ultra-short subpicosecond bunches call for special techniques of bunch length measurement including coherent radiation monitoring and the transverse deflecting cavity. The latter is also used to measure time dependant emittance and energy spread of slices along the bunch, which are critical to the lasing process within the FEL.  
slides icon Slides  
 
THPMS038 Magnetic Measurements and Simulations of a 4-Magnet Dipole Chicane for the International Linear Collider dipole, simulation, linear-collider, collider 3085
 
  • R. Arnold
  • V. N. Duginov, S. A. Kostromin, N. A. Morozov
    JINR, Dubna, Moscow Region
  • A. Fisher, C. Hast, Z. Szalata, M. Woods
    SLAC, Menlo Park, California
  • H. J. Schreiber, M. Viti
    DESY Zeuthen, Zeuthen
  T-474 at SLAC is a prototype BPM-based energy spectrometer for the ILC. We describe magnetic measurements and simulations for the 4-magnet chicane used in T-474. The ILC physics program requires better than 100 part-per-million (ppm) accuracy for energy measurements, which necessitates better than 50 ppm accuracy for magnetic field integral measurements. A 4-dipole chicane is used in T-474 with mid-chicane dispersion of 5-mm and magnetic fields of ~1 kGauss; similar to the current ILC parameters. Stability, reproducibility and consistency of magnetic measurements, including magnetic field maps for the T-474 dipole magnets, are presented using a moving wire, rotating coil, NMR probe, Hall probe and low-field fluxgate magnetometer. Measurements from SLAC's Magnet Test Lab facility as well as in situ measurements in End Station A (ESA) are presented, including measurements of residual magnetic fields in the T-474 chicane between the chicane magnets. Results are provided for an operational mode with a 1-hour calibration cycle, where the chicane magnets are operated in both polarities and at near-zero field.  
 
THPMS049 Investigations of the Wideband Spectrum of Higher Order Modes Measured on TESLA-style Cavities at the FLASH Linac dipole, simulation, higher-order-mode, electron 3100
 
  • S. Molloy
  • C. Adolphsen, K. L.F. Bane, J. C. Frisch, Z. Li, J. May, D. J. McCormick, T. J. Smith
    SLAC, Menlo Park, California
  • N. Baboi
    DESY, Hamburg
  • N. E. Eddy, L. Piccoli, R. Rechenmacher
    Fermilab, Batavia, Illinois
  • R. M. Jones
    UMAN, Manchester
  Funding: US DOE Contract #DE-AC02-76SF00515

Higher Order Modes (HOMs) excited by the passage of the beam through an accelerating cavity depend on the properties of both the cavity and the beam. It is possible, therefore, to draw conclusions on the inner geometry of the cavities based on observations of the properties of the HOM spectrum. A data acquisition system based on two 20 GS/s, 6 GHz scopes has been set up at the FLASH facility, DESY, in order to measure a significant fraction of the HOM spectrum predicted to be generated by the TESLA cavities used for the acceleration of its beam. The HOMs from a particular cavity at FLASH were measured under a range of known beam conditions. The dipole modes have been identified in the data. 3D simulations of different manufacturing errors have been made, and it has been shown that these simulations can predict the measured modes.

 
 
THPAN034 New Simulation Code for Synchrotron Radiation Based on a Real Beam Orbit synchrotron-radiation, simulation, synchrotron, alignment 3304
 
  • T. Abe
  A computer code to simulate synchrotron-radiation power and spatial distributions has been developed based on the method by T. Abe and H. Yamamoto*, where a real beam orbit is obtained by fitting measurements of beam-position monitors (BPMs) with some offset corrections for BPMs and magnet alignments. In this paper, the basic performance and application are presented. This code has been rewritten in Fortran95 so as to obtain expectable maximal speed-up by parallel computing, aiming at online alarm systems to take precautions against synchrotron-radiation damage, toward higher beam current accelerators.

* T. Abe and H. Yamamoto, Phys. Rev. ST Accel. Beams 7, 072802 (2004)

 
 
FRXC01 SNS RF System Performance and Operation klystron, linac, controls, cathode 3792
 
  • M. S. Champion
  The Spallation Neutron Source (SNS) Linac and Accumulator Ring utilize 100 Radio-Frequency (RF) systems for acceleration and bunching of the proton beam. Several different types of gridded tubes and klystrons are operated at 1, 2, 402.5 and 805 MHz, at power levels ranging from a few kilowatts to several megawatts to drive several types of accelerating cavities, both normal- and super-conducting. The RF systems are standardized, especially in the Linac, to ease operation and maintenance. Phase and amplitude control is achieved with a digital low-level RF control system. The RF systems operate reliably and support production of a high-quality low-loss proton beam. Various modifications and upgrades have been made or are in progress to enhance system reliability and performance. Planning is well underway for a power upgrade that will require an additional 36 RF systems.  
slides icon Slides  
 
FROAC02 RF Amplifier Choice for the ISAC Superconducting Linac linac, controls, diagnostics, power-supply 3798
 
  • I. V. Bylinskii
  • K. Fong, J. Lu, A. K. Mitra, C. Owen
    TRIUMF, Vancouver
  A superconducting linac is being commissioned at TRIUMF as an extension to the existing room temperature accelerator of exotic ions at ISAC. It will increase the isotope final energy from 1.5 to 6.5 MeV/u. Acceleration is accomplished in 40 bulk niobium quarter wave superconducting cavities operating at 106 and 141 MHz. Each cavity is energized from an independent RF amplifier with power rating up to 1 kW cw. Both vacuum tube and solid state amplifiers were considered as a viable option for the drivers. The paper compares many important parameters of these 2 amplifiers such as reliability, serviceability, capital and maintenance costs, as well as operating characteristics: gain linearity, phase noise, phase drift and others. Test results of prototypes of both types of amplifiers and 1 year operational experience of 20 tube amplifiers are discussed. Based on that the amplifier design requirements are formulated.  
slides icon Slides  
 
FRPMN043 Measurement of Beam Position Monitor Using HOM Couplers of Superconducting Cavities linac, pick-up, dipole, electron 4060
 
  • M. Sawamura
  The offset beam from the axis induces the HOMs in the cavities. These HOMs in superconducting cavities are usually damped by HOM couplers to suppress the beam instability. The induced HOM power is proportional to the beam offset and can be used to measure the beam position inside the cavity. The shifter magnet is installed to the JAEA superconducting ERL-FEL to vary the beam position. The HOM power from the HOM coupler with various beam position is measured. The result of the beam test is presented.  
 
FRPMN045 Beam Position Monitor and its Calibration in J-PARC LINAC linac, quadrupole, pick-up, background 4072
 
  • S. Sato
  • H. Akikawa, Z. Igarashi, N. Kamikubota, S. Lee
    KEK, Ibaraki
  • M. Ikegami
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  • H. Sako, G. B. Shen
    JAEA, Ibaraki-ken
  • T. Tomisawa, A. Ueno
    JAEA/LINAC, Ibaraki-ken
  The beam commissioning of J-PARC linac has been started in November 2006. Beam Position Monitors (BPMs) which have been calibrated on the bench setup with a scanning wire, utilize beam based calibration to relate the BPM center and the center of Q magnet. In this presentation, detail of installed BPM and the calibration methods are described.  
 
FRPMN051 Design of S-band Cavity BPM for HLS pick-up, resonance, electromagnetic-fields, gun 4102
 
  • Q. Luo
  • H. He, P. Li, P. Lu, B. Sun, J. H. Wang
    USTC/NSRL, Hefei, Anhui
  Funding: Supported by 985 Project of USTC 173123200402002

For the development of accelerators we require increasingly precise control of beam position. Cavity BPMs promise a much higher position resolution compared to other BPM types and manufacture of cavity BPMs is in general less complicated. The cavity BPM operating at S-band for HLS (Hefei Light Source) was designed. It consists of two cavities: a position cavity tuned to TM110 mode and a reference cavity tuned to TM010 mode. To suppress the monopole modes we use waveguides as pickups. Superheterodyne receivers are used in electronics for many cavity BPMs while we decide to use chip AD8302 produced by Analog Devices to process the signals. To simulate and calculate the electromagnetic field we use MAFIA.

 
 
FRPMN060 Beam Loss Simulation of SNS LINAC linac, simulation, radiation, beam-losses 4138
 
  • A. P. Zhukov
  • S. Assadi
    ORNL, Oak Ridge, Tennessee
  Funding: SNS is managed by UT-Batelle, LLC, under contract DE-AC05-00OR22725 for the U. S. Department of Energy.

We are developing a sophisticated system of beam loss pattern evaluation and residual radiation estimation. We have installed a number of Neutron Detectors and Ionization Chambers along LINAC. In this paper we present our implementation and simulation of the losses by inserting Faraday Cups, using Beam Stops and running Wire Scanners at different energies. The measured losses are simulated by 3-D transport codes (GEANT4, SHIELD, MCNPX). We compare two different sets of Beam Loss Monitors: Ionization Chambers (detecting X-ray and gamma radiation) and Photo-Multiplier Tubes with a neutron converter (detecting neutrons) and outline that such a combination is a better way to measure beam losses than relying on detectors of one type. We interpret the loss signal in terms of beam current lost in the SNS LINAC with accurate longitudinal loss distribution and plan to automate beam steering according to loss monitors readings by using vast Loss Pattern Database developed by simulating different loss scenarios with the transport codes.

 
 
FRPMN098 Compact PCI/PXI Based High Voltage Cards. controls, coupling, impedance, laser 4312
 
  • S. R. Babel
  Funding: BiRa Systems, Albuquerque, New Mexico

High voltage power modules find uses in many applications like the Photo multiplier Tubes (PMT), Ionization chambers, CRT systems testing, high voltage biasing for Avalanche Photodiodes, Photo detectors, X-ray tubes, Pulse generators which are used in radars, lasers, EMC testing and other imaging applications. Providing high voltage, to these applications, which can be remotely controlled in a small, confined area, is a problem many laboratories around the world face. The LV and the HV series of high voltage systems from BiRa Systems present experimenters with voltages ranging from several hundreds upto ± 5kV in a rugged CompactPCI / PXI chassis, running National Instruments' LabView. The CompactPCI architecture offers modularity, tight integration and low cost. Apart from that, the deterministic and real time nature of the operating system also allows these modules to be remotely controlled and monitored over the Ethernet. The high voltage cards can be easily custom tailored to a particular voltage and current requirement

 
 
FRPMS011 Design of an Electro-Optical Sampling Experiment at the AWA Facility laser, background, electron, alignment 3901
 
  • J. Ruan
  • H. Edwards, V. E. Scarpine, C.-Y. Tan, R. Thurman-Keup
    Fermilab, Batavia, Illinois
  • YL. Li, J. G. Power
    ANL, Argonne, Illinois
  • T. J. Maxwell
    Northern Illinois University, DeKalb, Illinois
  Funding: Supported by US DOE

The free space electro-optical (EO) sampling technique is a powerful tool for analyzing the longitudinal charge density of an ultrashort e-beam. In this paper, we present

  1. experimental results for a laser-based mock-up of the EO experiment* and
  2. a design for a beam-based, single-shot, EO sampling experiment using the e-beam from the Argonne Wakefield Accelerator (AWA) RF photoinjector.
For the mock-up, a tabletop terahertz experiment is conducted in the AWA laser room. The mock-up uses an IR beam incident on <110> ZnTe crystal to produce a THz pulse via optical rectification. Detection is based on the cross correlation between the THz field and the probe IR laser field in a second <110> ZnTe crystal. Potential application of this technique to the ILC accelerator test facility at Fermilab is also presented.

* Yuelin Li, Appl. Phys. Lett. 88, 251108, 2006

 
 
FRPMS030 ALS Mini IOC: An FPGA Embedded Processor Based Control System Module for Booster Magnet Ramping at the ALS booster, controls, power-supply, instrumentation 3991
 
  • J. M. Weber
  • M. J. Chin, CA. Timossi, E. C. Williams
    LBNL, Berkeley, California
  Funding: This work was supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U. S. Department of Energy under Contract No. DE-AC02-05CH11231.

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.