| Paper | Title | Other Keywords | Page | ||
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| MPPP007 | Operating Performance of the Low Group Delay Woofer Channel in PEP-II | feedback, damping, impedance, collider | 1069 | ||
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Funding: Work supported by U.S. Department of Energy contract DE-AC02-76SF00515. |
In PEP-II collider a dedicated low group-delay processing channel has been developed in order to provide high damping rates necessary to control the fast-growing longitudinal eigenmodes driven by the fundamental impedances of the RF cavities. A description of the digital processing channel operating at 9.81 MHz and capable of supporting finite impulse response (FIR) controllers with up to 32 taps will be presented. A prototype system has been successfully commissioned in the High-Energy Ring (HER) in May 2004. Operating experiences with the prototype and the newly determined limits on achievable longitudinal damping will be discussed and illustrated with experimental data. |
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| MPPP026 | Development of Longitudinal Coupling Impedance Measurement Platform for BEPCII | impedance, coupling, insertion, storage-ring | 1940 | ||
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Funding: Supported by NSFC 10375035. |
A coaxial line impedance measurement platform is developed for BEPCII. A pair of gradual change impedance matching section is designed and fabricated by numerical control milling machine. The special designed RF connector is applied to strengthen the inner conductor. The algorithm of TRL calibration is applied in the system to avoid the usage of a reference pipe for each device under test. The measurement is accomplished by a VNA under the control of the software written in LabView. |
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| MPPT051 | Reshimming of Tevatron Dipoles; A Process-Quality and Lessons-Learned Perspective | quadrupole, dipole, background, gun | 3156 | ||
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Funding: Work supported by the U.S. Department of Energy under Contract No. DE-AC02-76CH03000. |
Over the last two years corrections have been made for the skew quadrupole moment in 530 of the 774 installed dipoles in the Tevatron. This process of modifying the magnets in situ has inherent risk of degrading the performance of the superconducting accelerator. In order to manage the risk, as well as to ensure the corrections were done consistently, formal quality tools were used to plan and verify the work. The quality tools used to define the process and for quality control are discussed, along with highlights of lessons learned. |
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| TPAE014 | Optical Phase Locking of Modelocked Lasers for Particle Accelerators | laser, acceleration, vacuum, electron | 1389 | ||
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Funding: Department of Energy DE-FG03-97ER41043, DARPA DAAD19-02-1-0184. |
Particle accelerators require precise phase control of the electric field through the entire accelerator structure. Thus a future laser driven particle accelerator will require optical synchronism between the high-peak power laser sources that power the accelerator. The precise laser architecture for a laser driven particle accelerator is not determined yet, however it is clear that the ability to phase-lock independent modelocked oscillators will be of crucial importance. We report the present status on our work to demonstrate long term phaselocking between two modelocked lasers to within one dregee of optical phase and describe the optical synchronization techniques that we employ. |
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| TPAE065 | Development of a 20-MeV Dielectric-Loaded Accelerator Test Facility | electron, shielding, injection, acceleration | 3673 | ||
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Funding: Work supported by DOE and ONR. |
This paper will describe a joint project by the Naval Research Laboratory (NRL) and Argonne National Laboratory (ANL), in collaboration with the Stanford Linear Accelerator Center (SLAC), to develop a dielectric-loaded accelerator (DLA) test facility powered by the high-power 11.424-GHz magnicon that was developed by NRL and Omega-P, Inc. The magnicon can presently produce 25 MW of output power in a 250-ns pulse at 10 Hz, and efforts are in progress to increase this to 50 MW.* The facility will include a 5-MeV electron injector being developed by the Accelerator Laboratory of Tsinghua University in Beijing, China. The DLA test structures are being developed by ANL, and some have undergone testing at NRL at gradients up to ~8 MV/m.** SLAC is developing a means to combine the two magnicon output arms, and to drive an injector and accelerator with separate control of the power ratio and relative phase. The installation and testing of the first dielectric-loaded test accelerator, including injector, DLA structure, and spectrometer, should take place within the next year. The initial goal is to produce a compact 20-MeV dielectric-loaded test accelerator. *O. A. Nezhevenko et al., Proc. PAC 2003, p. 1128.**S. H. Gold et al., AIP Conf. Proc. 691, p. 282. |
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| TOPC004 | Tevatron Beam Position Monitor Upgrade | pick-up, antiproton, proton, injection | 410 | ||
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Funding: Operated by Universities Research Association Inc. under Contract No. DE-AC02-76CH03000 with the United States Department of Energy. |
The Tevatron Beam Position Monitor (BPM) readout electronics and software have been upgraded to improve measurement precision, functionality and reliability. The original system, designed and built in the early 1980s, became inadequate for current and future operations of the Tevatron. The upgraded system consists of 960 channels of new electronics to process analog signals from 240 BPMs, new front-end software, new online and controls software, and modified applications to take advantage of the improved measurements and support the new functionality. The new system reads signals from both ends of the existing directional stripline pickups to provide simultaneous proton and antiproton position measurements. Measurements using the new system are presented that demonstrate its improved resolution and overall performance. |
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| TPPT069 | Design Considerations for the Mechanical Tuner of the RHIC Electron Cooler SRF Cavity | vacuum, damping, resonance, cryogenics | 3786 | ||
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Funding: Work is supported by the DOD Joint Technology Office and by the U.S. Department of Energy. |
The ECX Project, Brookhaven Lab's predecessor to the RHIC e-Cooler, includes a prototype RF tuner mechanism capable of both coarse and fine tuning of the superconducting RF cavity. This tuner is adapted originally from a DESY design concept but with a longer stroke and significantly higher loads due to our very stiff cavity shape. Structural design, kinematics, controls, thermal and RF issues are discussed and certain improvements are proposed. |
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| TPPT079 | Performance Overview of the Production Superconducting RF Cavities for the Spallation Neutron Source Linac | SNS, linac, proton, insertion | 4048 | ||
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Funding: Work supported by U.S. Department of Energy under contract DE-AC05-84ER40150. |
As part of its efforts for the SNS construction project, Jefferson Lab has produced 23 cryomodules for the superconducting linac. These modules contained 81 industrially produced multicell Nb accelerating cavities. Each of these cavities was individually tested before assembly into a cryomodule to verify that they achieved the required performance. This ensemble of cavities represents the 3rd largest set of production superconducting cavities fabricated and tested to date. The timely qualification testing of such a collection of cavities offers both challenges and opportunities. Their performance can be characterized by achieved gradient at the required Qo, achieved peak surface field, onset of field emission, and observations of multipacting. Possible correlations between cavity performance and process parameters, only really meaningful in the framework of a large scale production effort, will also be presented. In light of the potential adoption of these cavities for projects such as the Rare Isotope Accelerator or Fermilab Proton Driver, such an analysis is crucial to their success. |
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| WPAE002 | Safety Management for the Cryogenic System of Superconducting RF System | vacuum, storage-ring, superconducting-RF, synchrotron | 832 | ||
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The installation of the helium cryogenic system for the superconducting RF cavity and magnet were finished in the National Synchrotron Radiation Research Center (NSRRC) at the end of October 2002. The first phase of this program will be commissioned at the end of 2004. This was the first large scale cryogenic system in Taiwan. The major hazards to personnel are cryogenic burn and oxygen deficient. To avoid the injury of the operators and meet the requirements of local laws and regulations, some safety measures must be adopted. This paper will illustrate the methods of risk evaluation and the safety control programs taken at NSRRC to avoid and reduce the hazards from the cryogenic system of the superconducting RF cavity and magnet system.
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| WPAE065 | Jefferson Lab's Trim Card II | power-supply, diagnostics, feedback, impedance | 3670 | ||
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Funding: This work was supported by DOE contract DE-AC05-84ER40150 Modification No. M175, under which the Southeastern Universities Research Association (SURA) operates the Thomas Jefferson National Accelerator Facility. |
Jefferson Lab’s Continuous Electron Beam Accelerator Facility (CEBAF) uses Trim Card I power supplies to drive approximately 1900 correction magnets. These trim cards have had a long and illustrious service record. However, some of the employed technology is now obsolete, making it difficult to maintain the system and retain adequate spares. The Trim Card II is being developed to act as a transparent replacement for its aging predecessor. A modular approach has been taken in its development to facilitate the substitution of sections for future improvements and maintenance. The resulting design has been divided into a motherboard and 7 daughter cards which has also allowed for parallel development. The Trim Card II utilizes modern technologies such as a Field Programmable Gate Array (FPGA) and a microprocessor to embed trim card controls and diagnostics. These reprogrammable devices also provide the versatility to incorporate future requirements. |
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| WPAE066 | PEP-II Large Power Supplies Rebuild Program at SLAC | power-supply, feedback, collider, monitoring | 3685 | ||
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Funding: Work supported by the U.S. Department of Energy under contract number DE-AC02-76SF00515. |
At PEP-II, seven large power supplies (LGPS) are used to power quad magnets in the electron-positron collider region. The LGPS ratings range from 72kW to 270kW, and were installed in 1997. They are unipolar off-line switch mode supplies, with a 6 pulse bridge rectifying 480VAC, 3-phase input power to yield 650VDC unregulated. This unregulated 650VDC is then input into one (or two) IGBT H-bridges, which convert the DC into PWM 16 kHz square wave AC. This high frequency AC drives the primary side of a step-down transformer followed by rectifiers and low pass filters. Over the years, these LGPS have presented many problems mainly in their control circuits, making it difficult to troubleshoot and affecting the overall accelerator availability. A redesign/rebuilding program for these power supplies was established under the coordination of the Power Conversion Department at SLAC. During the 2004 accelerator summer shutdown all the control circuits in these supplies were redesigned and replaced. A new PWM control board, programmable logic controller, and touch panel were all installed to improve LGPS reliability, and to make troubleshooting easier. In this paper we present the details of this rebuilding program and results. |
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| WPAE075 | Compact Digital High Voltage Charger | impedance, feedback, power-supply, synchrotron | 3964 | ||
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The operation of classical resonant circuit developed for the pulse energizing is investigated. The HV pulse or generator is very compact by a soft switching circuit made up of IGBT working at over 30 kHZ. The frequencies of macro pulses andμpulses can be arbitrarily tuned below resonant frequency to digitalize the HV pulse power. Theμpulses can also be connected by filter circuit to get the HVDC power. The circuit topology is given and its novel control logic is analyzed by flowchart. The circuit is part of a system consisting of a AC or DC LV power supply, a pulse transformer, the pulse generator implemented by LV capacitor and leakage inductance of the transformer, a HV DC or pulse power supply and the charged HV capacitor of the modulators.
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| WPAT007 | Control Loops for the J-PARC RCS Digital Low-Level RF Control | synchrotron, acceleration, feedback, damping | 1063 | ||
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The low-level radiofrequency control for the Rapic Cycling Syncrotron of J-PARC is based on digital signal processing. This system controls the acceleration voltages of 12 magnetic alloy loaded cavities. To achive a short overall delay, mandatory for stable loop operation, the data-processing is based on distributed arithmetics in FPGA. Due to the broadband characteristic of the acceleration cavities, no tuning loop is needed. To handle the large beam current, the RF system operates simultaneously with dual harmonics (h=2) and (h=4). The stability of the amplitude loops is limited by the delay of the FIR filters used after downconversion. The phase loop offers several operation modes to define the phase relation of (h=2) and (h=4) between the longitudinal beam signal and the vector-sum of the cavity voltages. Besides the FIR filters, we provide cascaded CIC filters with smoothly varying coefficients. Such a filter tracks the revolution frequency and has a substantially shorter delay, thereby increasing the stable operating region of the phase loops. The adaptive radial loop accumulates the orbit variation over several machine cycles to reduce the effects of measurement errors on the effective acceleration frequency program.
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| WPAT034 | The CEBAF Separator Cavity Resonance Control System | resonance, monitoring, linac, electron | 2339 | ||
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Funding: This work supported by the U.S. Department of Energy under contract DE-AC05-84ER40150. |
The CEBAF energy upgrade from 6 GeV to 12GeV will increase the range of beam energies available to the experimental halls. RF deflection cavities (separators) are used to direct the electron beam to the three experimental halls. Consequently with the increase in RF separator cavity gradient needed for the higher energies, RF power will also increase requiring the cavities to have active resonance control. At the 6 GeV energy, the cavities are tuned mechanically and then stabilized with Low Conductivity Water (LCW), which is maintained at constant temperature of 95o Fahrenheit. This is no longer feasible and an active resonance control system, that controls both water temperature and flow has been built. The system uses a commercial PLC with embedded PID controls to control water temperature and flow to the cavities. The system allows the operator to remotely adjust temperature/flow and consequently cavity resonance for the full range of beam energies. Ultimately closed loop control will be maintained by monitoring the cavities reflected power. This paper describes this system. |
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| WPAT047 | Solid-State 2MW Klystron Power Control System | klystron, cathode, vacuum, power-supply | 2950 | ||
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Under an SBIR effort for the DOE, Diversified Technologies, Inc. designed, built, and installed a solid state power control system for the Advanced Light Source klystrons at Argonne National Laboratory (ANL). This system consists of two major elements – a 100 kV, 20 A CW solid state series switch, and a solid state voltage regulator for the mod-anode of the klystron. The series switch replaces the existing mercury ignitron crowbar, eliminating these environmentally hazardous components while providing enhanced arc protection and faster return to transmit. The mod-anode voltage regulator uses series IGBTs, operating in the linear regime, to provide highly rapid and accurate control of the mod-anode voltage, and therefore the output power from the klystron. Results from the installation and testing of this system at ANL will be presented.
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| WPAT048 | Solid State Modulators for the International Linear Collider (ILC) | linear-collider, collider, power-supply, target | 2998 | ||
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Diversified Technologies, Inc. is developing two solid state modulator designs for the ILC under SBIR funding from the DOE. The first design consists of a 150 kV hard switch. The key development in this design is the energy storage system, which must provide 25 kJ per pulse, at very tight voltage regulation over the 1.5 millisecond pulse. DTI’s design uses a quasi-resonant bouncer (with a small auxiliary power supply and switch) to maintain the voltage flattop, eliminating the need for massive capacitor banks. The second design uses a solid state Marx bank, with ~10 kV stages, to drive the ILC klystron. In this design, staggered turn-on of the Marx stages provides voltage regulation without the need for large capacitor banks. This paper will discuss design tradeoffs, power supply and control considerations, and energy storage requirements and alternatives for both designs.
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| WPAT060 | SNS Low-Level RF Control System: Design and Performance | SNS, linac, feedback, damping | 3479 | ||
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Funding: ORNL managed by UT-Battelle for US DOE. |
A full digital Low-Level RF controller has been developed for SNS LINAC. Its design is a good example of a modern digital implementation of the classic control theory. The digital hardware for all the control and DSP functionalities, including the final vector modulation, is implemented on a single high-density FPGA. Two models for the digital hardware have been written in VHDL and Verilog respectively, based on a very low latency control algorithm, and both have been being used for supporting the testing and commissioning the LINAC to the date. During the commissioning, the flexibility and ability for precise controls that only digital design on a larger FPGA can offer has proved to be a necessity for meeting the great challenge of a high-power pulsed SCL. |
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| WPAT065 | HLS RF System Improvement in NSRL Phase II Project | vacuum, storage-ring, coupling, electron | 3653 | ||
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Hefei Light Source (HLS) is mainly composed of an 800 MeV electron storage ring and a 200 MeV Linac functioning as its injector. The RF system has been improved successfully for HLS storage-ring in NSRL Phase II Project. In this paper, the improvement of generator and power transmission system, the development of a new RF cavity and the perfection of RF controls are described in detail. The results and some analyses are presented.
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| WPAT085 | 4.2 K Operation of the SNS Cryomodules | SNS, linac, radiation, Spallation-Neutron-Source | 4173 | ||
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Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. SNS is a partnership of six national laboratories: Argonne, Brookhaven, Jefferson, Lawrence Berkeley, Los Alamos and Oak Ridge. |
The Spallation Neutron Source being built at the Oak Ridge National Laboratory employs eighty one 805 MHz superconducting cavities operated at 2.1 K for the H- beam to gain energy in the main linac from 187 MeV to about 1 GeV. The superconducting cavities and cryomodules with two different values of beta .61 and .81 have been designed and constructed at Jefferson Lab for operation at 2.1 K with unloaded Q’s in excess of 5x109. To gain experience in testing cryomodules in the SNS tunnel before the final commissioning of the 2.1 K Central Helium Liquefier, integration tests were conducted on a medium beta (.61) cryomodule at 4.2 K. This is the first time that a superconducting cavity system specifically designed for 2.1 K operation has been extensively tested at 4.2 K without superfluid helium. Even at 4.2 K it was possible to test all of the functional properties of the cryomodule and of the cavities. In particular, at a nominal BCS Qo˜7x108, simultaneous pulse operation of all three cavities in the cryomodule was achieved at accelerating gradients in excess of 12 MV/m. These conditions were maintained for several hours at a repetition rate of 30 pps. Details of the tests will be presented and discussed. |
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| RPAP048 | SNS Diagnostics Timing Integration | SNS, diagnostics, Spallation-Neutron-Source, target | 3001 | ||
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Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. |
The Spallation Neutron Source (SNS) accelerator systems will deliver a 1.0 GeV, 1.4 MW proton beam to a liquid mercury target for neutron scattering research. The accelerator complex consists of a 1 GeV linear accelerator, an accumulator ring and associated transport lines. The SNS diagnostics platform is PC-based running Windows XP Embedded for its OS and LabVIEW as its programming language. Coordinating timing among the various diagnostics instruments with the generation of the beam pulse is a challenging task that we have chosen to divide into three phases. First, timing was derived from VME based systems. In the second phase, described in this paper, timing pulses are generated by an in house designed PCI timing card installed in ten diagnostics PCs. Using fan-out modules, enough triggers were generated for all instruments. This paper describes how the Timing NAD (Network Attached Device) was rapidly developed using our NAD template, LabVIEW’s PCI driver wizard, and LabVIEW Channel Access library. The NAD was successfully commissioned and has reliably provided triggers to the instruments. This work supports the coming third phase where every NAD will have its own timing card. |
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| RPAT009 | FPGA-Based Instrumentation for the Fermilab Antiproton Source | antiproton, diagnostics, instrumentation, proton | 1159 | ||
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We have designed and built low-cost, low-power, ethernet-based circuit boards to apply DSP techniques to several instrumentation upgrades in the Fermilab Antiproton Source. Commodity integrated circuits such as direct digital synthesizers, D/A and A/D converters, and quadrature demodulators enable digital manipulation of RF waveforms. A low cost FPGA implements a variety of signal processing algorithms in a manner that is easily adapted to new applications. An embedded microcontroller provides FPGA configuration, control of data acquisition, and command-line interface. A small commercial daughter board provides an ethernet-based TCP/IP interface between the microcontroller and the Fermilab accelerator control network. The board is packaged as a standard NIM module. Applications include Low Level RF control for the Debuncher, readout of transfer-line Beam Position Monitors, and narrow-band spectral analysis of diagnostic signals from Schottky pickups.
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| RPAT011 | Digital Signal Processing the Tevatron BPM Signals | pick-up, antiproton, closed-orbit, proton | 1242 | ||
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Funding: Fermilab |
The Beam Position Monitor (BPM) readout system at Fermilab’s Tevatron has been updated and is currently being commissioned. The new BPMs use new analog and digital hardware to achieve better beam position measurement resolution. The new system reads signals from both ends of the existing directional stripline pickups to provide simultaneous proton and antiproton position measurements. The signals provided by the two ends of the BPM pickups processed by analog band-pass filters and sampled by 14-bit ADCs at 74.3MHz. A crucial part of this work has been the design of digital filters that process the signal. This paper describes the digital processing and estimation techniques used to optimize the beam position measurement. The BPM electronics must operate in narrow-band and wide-band modes to enable measurements of closed-orbit and turn-by-turn positions. The filtering and timing conditions of the signals are tuned accordingly for the operational modes. The analysis and the optimized result for each mode is presented. |
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| RPAT015 | First Results of a Digital Beam Phase Monitor at the Tevatron | proton, antiproton, synchrotron, injection | 1428 | ||
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A digital Beam Phase Monitor has been installed on the Tevatron ring. This device will be mainly use to diagnose the energy oscillations of each of the 36 × 36 protons and antiprotons bunches as well as to study the transient beam loading. The first results obtained from the Beam Phase Monitor will be presented on the paper.
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| RPAT071 | Digital Beam Position Monitor for the Happex Experiment | instrumentation, monitoring, linac, survey | 3841 | ||
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Funding: This work was supported by DOE contract No. DE-AC05-84ER40150. |
The proposed HAPPEX experiment at CEBAF employs a three cavity monitor system for high-precision (1 mm), high-bandwidth (100 kHz) position measurements. This is performed using a cavity triplet consisting of two TM110-mode cavities (one each for X and Y planes) combined with a conventional TM-010-mode cavity for a phase and magnitude reference. Traditional systems have used the TM010 cavity output to directly down convert the BPM cavity signals to base band. The Multi-channel HAPPEX digital receiver simultaneously I/Q samples each cavity and extracts position using a CORDIC algorithm. The hardware design consists of a digital receiver daughter board and digital processor motherboard that resides in a VXI crate. The daughter board down converts 1.497 GHz signals from the TM010 cavity and X and Y signals from the TM110 cavities to 4 MHz, and extracts the quadrature digital signals. The motherboard processes this data and computes beam intensity and X-Y positions with a resolution of one mm, 100 kHz output bandwidth, and overall latency of ten microseconds. The results are available in both analog and digital format. |
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| RPPE022 | Machine Protection System for Concurrent Operation of RHIC and BLIP | proton, linac, radiation, monitoring | 1754 | ||
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Funding: Work performed under Contract Number DE-AC02-98CH10886 with the auspices of the U.S. Department of Energy. |
The Brookhaven 200 MeV linac is a multipurpose machine used to inject low intensity polarized protons ultimately ending up in RHIC as well as to inject high intensity protons to BLIP, a medical isotope production facility. If high intensity protons were injected to RHIC by mistake, administrative radiation limits could be exceeded or sensitive electronics could be damaged. In the past, the changeover from polarized proton to high intensity proton operation has been a lengthy process, thereby never allowing the two programs to run simultaneously. To remedy this situation and allow for concurrent operation of RHIC and BLIP, an active interlock system has been designed to monitor current levels in the AGS using two current transformers with fail safe circuitry and associated electronics to inhibit beam to RHIC if high intensity is detected. |
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| RPPE074 | The Multichannel Deflection Plates Control System for the ALF Facility at the APS | ion, octupole, power-supply, free-electron-laser | 3937 | ||
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Funding: Work supported by U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. W-31-109-ENG-38. |
A deflection plate control system was developed as part of SPIRIT (Single Photon Ionization / Resonant Ionization to Threshold), a new secondary neutral mass spectrometry (SNMS) instrument that uses tunable vacuum ultraviolet light from the ALF (Argonne Linear Free-electron laser) facility at the APS for postionization. The system comprises a crate controller with PC104 embedded computer, 32 amplifiers, and two 1-kV power supplies. Thirty-two D/A converters are used to control voltages at the deflection plates within ± 400 V with 100-mV resolution. An algorithm of simultaneous sweeping of up to 16 XY areas with 10-μs time resolution also has been implemented in the embedded computer. The purpose of the system is to supply potentials to various ion optical elements for electrostatic control of keV primary and secondary ion beams in this SNMS instrument. The control system is of particular value in supplying (1) bipolar potentials for steering ions, (2) multiple potentials for octupole lenses that shape the ion beams, and (3) ramped deflection potentials for rastering the primary ion beam. The system has been in use as part of the SPIRIT instrument at the ALF facility since 2002. |
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| RPPE077 | A Complete System for Operation of a Superconducting Magnet | power-supply, wiggler, superconducting-magnet, monitoring | 4003 | ||
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Funding: National Science Foundation. |
A complete system for operating, protecting and monitoring a superconducting magnet is described. This system is used in CESR (Cornell Electron Storage Ring) at Cornell University's Laboratory for Elementary Particle Physics (LEPP) for the CESR superconducting wigglers, part of the accelerator upgrade in pursuit of the CESR charm physics program known as CESR-c. |
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| ROPA002 | CLS: A Fully Open-Source Control System | power-supply, storage-ring, linac, synchrotron | 136 | ||
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The Canadian Light Source is one of the first major accelerator facility to adopt a fully open source control system. The control system is based on Experimental Physics and Industrial Control System (EPICS) in use at may other facilities. From the outset CLS utilised RTEMS and Linux as the underlying operating systems for real-time control computers, operator interface computers and servers. When communicating with PLC and other intelligent devices CLS has also adopted a policy of using open communications protocols where possible. Combined these strategies have lead to a system that can easily evolve over the life of the facility without being tied to specific hardware or software suppliers. The operational experience over the past few years has indicates the selected architecture is sufficiently robust and reliable.
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| ROPA004 | CEBAF Control Room Renovation | plasma, monitoring, linac, synchrotron | 378 | ||
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The Machine Control Center at Jefferson Lab's Continuous Electron Beam Accelerator Facility was initially constructed in the early 1990s and based on proven technology of that era. Through our experience over the last 15 years and in our planning for the facilities 12 GeV upgrade we reevaluated the control room environment to capitalize on emerging visualization and display technologies and improve on workflow processes and ergonomic attributes. This effort also sets the foundation for the redevelopment of the accelerator's control system to deliver high reliability performance with improvements in beam specifications management and information flow. The complete renovation was performed over a three-week period with no interruption to beam operations. We present the results of this effort.
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| ROPA010 | Component/Connection/Signal Modeling of Accelerator Systems | power-supply, vacuum, photon | 707 | ||
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Funding: Work supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. W-31-109-ENG-38. |
This paper presents a pragmatic global approach to data modeling a complex facility such as a particle accelerator. By successively partitioning the facility into collaborating subsystems, one eventually arrives at the component level–the point at which the subsystem is replaceable as a single unit. The fundamental goal of the model is to capture the dynamical relationships (i.e., the connections) that exist among the accelerator components. Components participate in one or more of three connection types: control, housing, and power. These connections are captured in a multi-hierarchical model capable of handling any component of the accelerator, from the macro scale (magnets, power supplies, racks, etc.) to the embedded scale (circuit board components), if desired. The connection approach has been used to model the signal flows between the component via their port connections. The result is a schema for a cable database that provides end-to-end signal tracing throughout the facility. The paper will discuss the multi-hierarchy nature of the model and its success in replacing the "Revision Controlled Drawing" approach to system documentation. |
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| FOAC005 | Reliability and Availability Studies in the RIA Linac Driver | linac, simulation, site, power-supply | 443 | ||
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Funding: Work supported by the U. S. Department of Energy under contract W-31-109-ENG-38. |
The RIA facility will include various complex systems and must provide radioactive beams to many users simultaneously. The availability of radioactive beams for most experiments at the fully-commissioned facility should be as high as possible within design cost limitations. To make a realistic estimate of the achievable reliability a detailed analysis is required. The RIA driver linac is a complex machine containing a large number of SC resonators and capable of accelerating multiple-charge-state beams. At the pre-CDR stage of the design it is essential to identify critical facility subsystem failures that can prevent the driver linac from operating. The reliability and availability of the driver linac are studied using expert information and data from operating machines such as ATLAS, APS, JLab, and LANL. Availability studies are performed with a Monte-Carlo simulation code previously applied to availability assessments of the NLC facility [http://www.slac.stanford.edu/xorg/accelops/Full/LCoptsfull] and the results used to identify subsystem failures that affect most the availability and reliability of the RIA driver, and guide design iterations and component specifications to address identified problems. *J.A. Nolen, Nucl. Phys. A. 734 (2004) 661. |
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| FPAT006 | CHEF: An Interactive Program for Accelerator Optics Calculations | lattice, optics, factory, target | 988 | ||
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Funding: Fermilab is operated by Universities Research Association Inc. under Contract No. DE-AC02-76CH03000 with the United States Department of Energy. |
We introduce CHEF, a program built on a "Collaborative Hierarchical Exploratory Framework" for doing optical calculations in accelerator physics. CHEF organizes and shares information between independent components that employ graphical user interfaces for interactive use. Among them are: a browser to display the beamline model's structure; a site viewer to show a line's geometry; phase space windows to oversee development of tracking calculations; a trace window to display the passage of a probe particle through beam position monitors; a plotter for displaying optical functions; a parser which constructs beamline models defined in MAD8 format and allows for interactive editing and debugging of the lattice files. Calculations are carried out by a hierarchy of C++ class libraries, most notably: MXYZPTLK handles automatic differentiation and differential algebra; BEAMLINE contains classes for modeling accelerator components; PHYSICS_TOOLKIT encapsulates specific calculations. Python bindings to these libraries and to CHEF's components, in conjunction with an embedded interpreter, provide a mechanism to extend and customize CHEF's functionality. |
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| FPAT008 | SDA-Based Diagnostic and Analysis Tools for Collider Run II | proton, collider, acceleration, diagnostics | 1099 | ||
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Funding: Fermilab (Department of Energy). |
Operating and improving the understanding of the Fermilab Accelerator Complex for the colliding beam experiments requires advanced software methods and tools. The Shot Data Acquisition and Analysis (SDA) has been developed to fulfill this need. Data is stored in a relational database, and is served to programs and users via Web-based tools. Summary tables are systematically generated during and after a store. These tables, the Supertable, and the Recomputed Emittances and Recomputed Intensity tables are discussed here. This information is also accesible in JAS3 (Java Analysis Studio version 3). |
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| FPAT010 | Automated Beam Steering Using Optimal Control | target, quadrupole, simulation, lattice | 1213 | ||
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Funding: Work supported by the U.S. Department of Energy. |
We present an optimal control strategy for beam steering where the operator can specify a variety of optimality conditions by selecting a parameter set describing an optimally steered beam. Novel approaches here include the ability to base optimality on the beam state throughout the entire beamline, rather than just at BPM locations. Moreover, we also may use the trajectory slope to base our optimality criteria. To achieve this feature we must introduce model dependency. Specifically, we predict the state of the beam from BPM measurements, the set-point of the steering magnets, and a model of beam behavior. The predictions are then used to calculate the optimum setting for steering magnets. The optimal control problem has rich mathematical structure that can be exploited and we cover some topics as they apply to accelerator systems. ckallen@lanl.gov |
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| FPAT016 | PASTA – An RF Phase and Amplitude Scan and Tuning Application | linac, RF-structure, SNS, Spallation-Neutron-Source | 1491 | ||
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Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. |
To assist the beam commissioning in the Spallation Neutron Source (SNS) linac, a general purpose RF tuning application has been written to help set RF phase and amplitude. It follows the signature matching procedure described in Ref.* The method involves varying an upstream Rf cavity amplitude and phase settings and comparing the measured downstream beam phase responses to model predictions. The model input for cavity phase and amplitude calibration and for the beam energy are varied to best match observations. This scheme has advantages over other RF tuning techniques of not requiring intercepting devices (e.g. Faraday Cups), and not being restricted to a small linear response regime near the design values. The application developed here is general and can be applied to different RF structure types in the SNS linac. Example applications in the SNS Drift Tube Linac (DTL) and Coupled Cavity Linac (CCL) structures will be shown. *T.L. Owens, M.B. Popovic, E.S. McCrory, C.W. Schmidt, L. J. Allen, "Phase Scan Signature Matching for Linac Tuning," Particle Accelerators, 1994 Vol 98, p. 169. |
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| FPAT044 | Low Cost Magnetic Field Controller | power-supply, permanent-magnet, dipole, microtron | 2833 | ||
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Funding: Fundacao de Amparo a Pesquisa do Estado de Sao Paulo-FAPESP, Conselho Nacional de Desenvolvimento Cientifico e Tecnologico-CNPq. |
The Physics Institute of the University of São Paulo (IFUSP) is building a continuous wave (cw) racetrack microtron. This machine has several dipole magnets, like the first and second stage recirculators, and a number of smaller ones in the transport line. These magnets must produce very stable magnetic fields to allow the beam to recirculate along very precise orbits and paths. Furthermore, the fields must be reproducible with great accuracy to allow an easier setup of the machine, though the effects of hysteresis tend to jeopardize the reproducibility. If the magnetic field is chosen by setting the current in the coils, temperature effects over the magnet and power supply tend to change the field. This work describes an inexpensive magnetic field controller that allows a direct measure of the magnetic field through an Hall probe. It includes a microcontroller running a feedback algorithm to control the power supply, in order to keep the field stable and reproducible. The controller can also execute algorithms to ramp up and down the power supply in a specific mode, in order to reduce hysteresis. |
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| FPAT049 | Upgrade of the PF Ring Vacuum Control System | vacuum, ion, cathode, storage-ring | 3061 | ||
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Having been operated for more than two decades, the PF ring vacuum control system had become superannuated. The system reliability had been degraded and the maintenance work had been difficult. In addition, the device operability had not been high because the operating software, written in BASIC, had been running in a stand-alone computer. In the summer of 2004, the vacuum control system was upgraded to solve these problems. In this upgrade, the operating system was constructed in the EPICS environment. And numerous NIM modules composing hardware interfaces between vacuum device controllers and the operating computers were replaced by reliable PLCs.
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| FPAT061 | CEBAF Distributed Data Acquisition System | linac, beam-losses, klystron, electron | 3541 | ||
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Funding: This work was supported by DOE contract DE-AC05-84ER40150 Modification No. M175, under which the Southeastern Universities Research Association (SURA) operates the Thomas Jefferson National Accelerator Facility. |
There are thousands of signals distributed throughout Jefferson Lab’s Continuous Electron Beam Accelerator Facility (CEBAF) that are useful for troubleshooting and identifying instabilities. Many of these signals are only available locally or monitored by systems with small bandwidths that cannot identify fast transients. The Distributed Data Acquisition (Dist DAQ) system will sample and record these signals simultaneously at rates up to 40 Msps. Its primary function will be to provide waveform records from signals throughout CEBAF to the Experimental Physics and Industrial Control System (EPICS). The waveforms will be collected after the occurrence of an event trigger. These triggers will be derived from signals such as periodic timers or accelerator faults. The waveform data can then be processed to quickly identify beam transport issues, thus reducing down time and increasing CEBAF performance. The Dist DAQ system will be comprised of multiple standalone chassis distributed throughout CEBAF. They will be interconnected via a fiber optic network to facilitate the global triggering of events. All of the chassis will also be connected directly to the CEBAF Ethernet and run EPICS locally. This allows for more flexibility than the typical configuration of a single board computer and other custom printed circuit boards (PCB) installed in a card cage. allison@jlab.org |
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| FPAT063 | Control System for the ORNL Multicharged Ion Research Facility High-Voltage Platform | ion, ion-source, vacuum, power-supply | 3591 | ||
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Funding: Work supported by U. S. DOE Office of Fusion Energy Sciences and Office of Basic Energy Sciences under contract No. DE-AC05-00OR22725 with UT-Battelle, LLC. |
A control system for the 250-kV platform and beamlines for accelerating and transporting multiply-charged ion beams produced by an all-permanent-magnet ECR ion source has been developed at the ORNL Multicharged Ion Research Facility. The system employs Experimental Physics and Industrial Control System (EPICS) software controlling an Allen-Bradley ControlLogix Programmable Logic Controller (PLC). In addition to the I/O control points of the PLC, other devices are controlled directly by the EPICS computer through RS-232 and GPIB interfaces. PLC chassis are located at each major electrical potential of the facility, that is, at the ECR source potential, at the platform potential, and at ground potential used in the beamlines transporting ions to the various experimental end-stations. Connection of the control system components to the EPICS host is accomplished via EtherNet, including fiber optic links to the HV platform. The user interface is designed with the Extensible Display Manager (EDM) software and custom applets perform such tasks as mass-to-charge ratio scans of the platform analyzing magnet and archival of source and beamline operating parameters. |
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| FPAT064 | Experience with the EPICS PV Gateway at the APS | monitoring, photon | 3621 | ||
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Funding: Work supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. W-31-109-ENG-38. |
The EPICS PV Gateway has become a stable, high-performance application that provides access to process variables while minimizing the impact on critical IOCs and implementing additional access security. The additional access security typically prevents write access but is highly configurable. The Advanced Photon Source (APS) currently uses 40 Gateways running on 11 machines to provide access to the machine network from the offices and for the individual experimental teams. These include reverse Gateways that allow administration of all 40 APS Gateways from a single MEDM screen, even though the Gateways are running on separate networks. This administration includes starting, stopping, making and viewing reports, and viewing and editing access security files. There is one Gateway that provides process variable renaming. This paper provides an overview of the Gateways at the APS and describes the procedures that have been set up to use and administer them. |
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| FPAT078 | Supporting Cavity Production Using an Engineering Data Management System | site | 4024 | ||
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The reliable production of superconducting cavities is an essential issue for any future accelerator applying the “cold” technology. At DESY the complex manufacturing process is supported by an engineering data management system (EDMS). During the mechanical manufacturing process many quality checks are performed and their results are documented in inspection sheets, which are stored in the system and used for controlling. The EDMS further controls the subsequent preparation process by automatically creating and issuing work instructions for the treatment of the surfaces of the cavities. In parallel the necessary documentation for quality assurance is generated. The documentation is linked to the product breakdown structure; this enables users to easily navigate from inspection sheets of selected components forward to their 3D CAD model as well as back to the results of the examination of the original niobium sheet. The poster presents the structural approach for the documentation using a commercially available EDMS. Supporting the lifecycle by electronic workflow techniques is described.
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| FPAT090 | ExperimentDesigner: A Tcl/Tk Interface for Creating Experiments in EPICS | synchrotron, kicker, monitoring, feedback | 4245 | ||
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Funding: Work supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. W-31-109-ENG-38. |
ExperimentDesigner is a Tcl/Tk interface that allows users to easily design and run complicated experiments using a convenient graphical user interface (GUI). Features include: process variable monitoring, which pauses the experiment when values are out of range; user-defined initialization, execution, and finalization sequences; support of complex execution chains containing actions such as setting controls, reading values, running external programs, interacting with the user, etc.; collection of output data for convenient postprocessing; saving and loading of experiment configurations; convenient use of SDDS Toolkit programs; and execution of experiments from the command line without a GUI. |
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