BNL, Upton, Long Island, New York
Hundred megawatt level fast ramping power converters to drive proton and heavy ion machines are under research and development at accelerator facilities in the world. This is a leading edge technology. There are several topologies to achieve this power level. Their advantages and related issues will be discussed.
BNL, Upton, Long Island, New York
Funding: US DOE Office of Basic Energy Sciences
Discrete corrector magnets are used for the 230 horizontal and vertical steering magnets in the NSLS-II storage ring. A unique design incorporates both dipole and skew quad correctors for(DC) steering in the same magnet. Separate AC (orbit feedback) correctors have also been designed. Comparison with alternate designs are presented as well as prototype measurements
Fermilab, Batavia
Funding: Work supported by the U.S. Department of Energy
The fabrication of the multi-element corrector magnets for the Fermilab Booster synchrotron has just been completed. These water-cooled packages include six different corrector types - normal and skews oriented dipole, quadrupole and sextupole elements. They will provide full orbit control, tune and chromaticity of the beam over the whole range of Booster energies, from 0.4 GeV to 8 GeV. During production, a set of quality assurance measurements were performed, including special thermal tests. This paper summarizes the results from these measurements as well as discussing some specific steps of the magnet fabrication process.
KEK, Ibaraki
Tigold, Chiba 289-1226
KFG, NEUSS
KYOCERA Corporation, Higashiomi-city, Shiga
MELCO SC, Tsukuba
Nichicon (Kusatsu) Corporation, Shiga
The KEK Linac delivers the beam to KEK-Photon factory storage ring, KEKB ring and the advanced ring for photon factory. In order to deliver the beam to the KEK-photon factory and KEKB ring simultaneously, the pulsed bending magnet was installed at the end of KEKB Linac. The pulsed bending magnet extract 2.5GeV electron beam to the PF beam transfer line. The deflection angle of the magnet is 0.114 radians and the field strength is almost 1.22T. The peak current stability is better than 0.1% at 24kA operation. The maximum repetition rate is 25Hz. The 1.2m long ceramic chamber is inserted into the 1m long magnet. This system makes possible the top up operation of PF ring.
KEK, Ibaraki
KEKB linac is a 600 m long electron linac and is used to deliver beam to four rings, KEKB HER ring (electron, 8 GeV), KEKB LER ring (positron, 3.5 GeV),PF ring (electron, 2.5 GeV) and PF-AR ring (electron, 6.5 GeV). KEKB rings are operated under top-up injection mode and have occupied the current linac operation mostly. Simultaneous injection to three rings (KEKB HER and KEKB LER and PF) is required due to the top-up injection to PF ring is required recently. We have developed the pulsed bending magnet for this. This magnet produces 114 mrad deflection angle for 2.5 GeV PF beam. The fast switching between KEKB and PF can be performed up to 25 Hz. We will describe this magnet system in detail.
NSRRC, Hsinchu
Abstract A 3-GeV electron-storage ring with tiny emittance has been designed for the Taiwan Photon Source (TPS) that will provide one of the world's brightest synchrotron x-ray sources. Sextupole magnets for the booster ring (BR) serve to correct the chromaticity of the beam particles. As an AC power supply is generally used in a booster ring to raise beam particles to a required energy, a power supply at 3 Hz AC is used to charge the sextupole magnet, which would induce eddy currents in the vacuum chamber resulting in a magnetic multipole field. As an aspect of the magnet design, decreasing the effect of an eddy current on the homogeneity of the magnetic field, the geometry and material of the chamber must be considered. We demonstrate the effects of an eddy current on the homogeneity of a magnetic field for a vacuum chamber of various types, and we discuss the magnetic circuit and the conductor design of the booster-ring sextupole. Analysis of the multipole field and eddy-current loss were included to assure the accuracy of the magnetic circuit design.
JLAB, Newport News, Virginia
Funding: Work supported by the US DOE Contract #DE-AC05-060R23177 and the Commonwealth of Virginia.
The characteristics of the system of “SF” Sextupoles for the infrared Free Electron Laser Upgrade at the Thomas Jefferson National Accelerator Facility (JLab) are described. These eleven sextupoles possess a large field integral (2.15 T/m) with ± 0.01% field quality over a 150 mm width within a very short effective length (150 mm pole length) and have field clamps for fast field roll-off. The field integrals reproduce extremely well with good absolute resolution (± 0.1%). The simple, two-dimensional shape pole tips (directly from the original 3-D RADIA magnetic model) of these “all ends” magnets include the correction for end fields. Magnetic measurements are compared to the model. The system’s hysteresis protocol and power supplies were also used for the measurement process to enhance reproducibility in service, a recent initiative at JLab. The intricacies of magnetic measurement using the JLab field probe based Stepper Stand are described. The challenges of developing the in-house design power supplies for these magnets, based on use of a low quality supply brought to 0.001% current regulation by a CAN-Bus control are described.
LBNL, Berkeley, California
Funding: This work is supported by the Office of Science, United States Department of Energy under DOE contract DE-AC02-05CH11231.
The Muon Ionization Cooling Experiment (MICE) is an international collaboration that will demonstrate ionization cooling in a section of a realistic cooling channel using a muon beam at Rutherford Appleton Laboratory (RAL) in the UK. At each end of the cooling channel a spectrometer solenoid magnet consisting of five superconducting coils will provide a 4 tesla uniform field region. The scintillating fiber tracker within the magnet bore tubes will measure the emittance of the muon beam as it enters and exits the cooling channel. The 400 mm diameter warm bore, 3 meter long magnets incorporate a cold mass consisting of two coil sections wound on a single aluminum mandrel: a three-coil spectrometer magnet and a two-coil section that matches the solenoid uniform field into the MICE cooling channel. The fabrication of the spectrometer solenoids has been completed, and preliminary testing and field mapping of the magnets is nearly complete. The key design features of the spectrometer solenoid magnets are presented along with a summary of the progress on the testing and magnetic measurements.
STFC/RAL/ISIS, Chilton, Didcot, Oxon
STFC/RAL/ASTeC, Chilton, Didcot, Oxon
Imperial College of Science and Technology, Department of Physics, London
STFC/RAL, Chilton, Didcot, Oxon
The RAL Front End Test Stand (FETS) is being constructed to demonstrate a chopped H- beam of up to 60 mA at 3 MeV with 50 pps and sufficiently high beam quality for future high-power proton accelerators (HPPA). High power proton accelerators with beam powers in the several megawatt range have many applications including drivers for spallation neutron sources, neutrino factories, waste transmuters and tritium production facilities. The aim of the FETS project is to demonstrate that chopped low energy beams of high quality can be produced and is intended to allow generic experiments exploring a variety of operational conditions. This paper details the first results from the initial operation of the ion source.
GSI, Darmstadt
The 'Facility of Antiproton and Ion Research' (FAIR) project will be realized at the 'GSI Helmholtzzentrum für Schwerionenforschung GmbH' (Darmstadt, Germany) in the scope of a large international collaboration. One of the FAIR storage rings is the collector ring (CR) whose main purpose is to allow a fast cooling of secondary beams (rare isotopes and antiprotons). The RF system of the collector ring has to allow pulsed operation (40kV, duty cycle 5e-4) as well as continuous operation (2kV) in the frequency range of 1.2 to 1.4MHz. The detailed conceptual design of this RF system is introduced here. It will be based (similar to the existing RF system 'SIS18 bunch compressor' which will also be presented at PAC09) on two inductively loaded quarter wavelength coaxial resonators operating on a common ceramic gap. The resonator will be loaded with twelve ring cores (rout=313mm, rin=145mm, h=25mm) of a cobalt based amorphous magnetic alloy (VitroVac6030F); it will be cooled by forced air. The cavity will be driven by a push-pull amplifier operated in class A consisting of two tetrodes (TH555A) that will be coupled inductively to the cavity.
ANL, Argonne
Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
The redesign, construction, and high-power testing of a 95-kV DC, 2MW water-cooled resistive load has been completed. This load was built and installed to test and troubleshoot the Advanced Photon Source (APS) 352-MHz high voltage klystron power supplies. The original resistive load*,** was modified to enhance and improve the load performance .In this paper, we describe the redesign of the DC load, report on the recent test results, and discuss it’s performance improvements.
*D. Horan et al., “A 2-Megawatt Load for Testing High Voltage DC Power Supplies”.
** D. Horan et al., “Performance of a 2-Megawatt High Voltage test Load”.
Diversified Technologies, Inc., Bedford, Massachusetts
Funding: U.S. Department of Energy SBIR Program
Constructing and supporting a wide range of RF amplifiers for research accelerators at is costly at present. This is because amplifiers to date have been designed for a single application, and have little commonality in their design and control interfaces. Diversified Technologies, Inc. (DTI) is developing a modular RF amplifier design for a wide range of amplifier requirements. Amplifiers built on this model have common design, controls, and spares, independent of frequency or power. The amplifier design combines a solid-state RF driver, power conditioning, and controls with a high-power vacuum electronic device, giving high performance at a low cost. In this paper, DTI will describe results of the first implementation of the amplifier, which delivers 20 kW CW at 704 MHz.
KEK, Ibaraki
Four klystron power supplies that can provide a typical voltage of 40kV (current 8A) are used for the PF storage ring at High Energy Accelerator Research Organization (KEK). The original power suplies were fabricated during 1979-1987. Although the power supplies have been operated well, we anticipate some difficulty in maintaining them in future. Then, we planned to renew them by stages. As the first step, we renewed one of the power supplies in 2003. The renewed power suplly have been operated well without any trouble. As the second step, we updated another power supply in the summer of 2008. The renewed power supply is equipped with a solid-state high-voltage (HV) switch that is made of insulated gate bipolar transistors (IGBT) for klystron protection. The renewed power supply have been operated well from September, 2008. We report the performance of the new power supply.
LANL, Los Alamos, New Mexico
The LANSCE linac RF system consists of four 201.25 MHz RF stations that supply RF power to the drift tube linac(DTL), and forty-four 805 MHz RF stations, that supply RF power to the coupled-cavity linac(CCL). There are four large high voltage power supplies for the DTL RF systems. Seven high voltage power supplies provide the power for the 805 MHz klystrons. All power supplies consist of a transformer/rectifier, Inductrol Voltage Regulator (IVR) and a capacitor bank with crowbar protection. After 39 years of operation, some components are approaching the end of life and will be refurbished through the LANSCE-R project to ensure the reliability of the machine until 2025. An analysis of the oil in the high voltage power supply units was done to assess their health to determine if units need to be replaced or repaired as part of LANSCE-R. Since 1998 the oil in each unit has been sampled and tested annually, and reprocessed when required. Gas-in-oil data for these units from 1998 to present was analyzed. The levels of each gas component, trends in the data and the significance of the each dissolved gas are discussed. The health of the units is assessed.
Nano, Moscow
RAS/INR, Moscow
Solid State High Power RF System is proposed for XFEL and ILC. It includes individual RF power supply for each SC cavity and common control system. Each RF power supply includes Solid State Generator, circulator and Q-tuner. Triggering, synchronization, output power and phase of each Solid State Generator are controlled from the common control system through fiber-optic lines. Main parameters of Solid State Generator are: frequency 1.3 GHz, peak power 128 kW, pulse length 1.4 msec, repetition rate 10 Hz, average power 1.8 kW, CW power 2.5 kW. Advantages of Solid State High Power RF System are: simple triggering, synchronization, output power and phase adjustment for all cavities separately, operation both in pulse and in CW modes, unlimited lifetime, no high voltage, no oil-tank, compactness.
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
The Muon Ionisation Cooling Experiment (MICE) at the Rutherford Appleton Laboratory uses normal conducting copper cavities to re-accelerate a muon beam after it has been retarded by liquid hydrogen absorbers. Each cavity operates at 200MHz and requires 1MW of RF power in a 1ms pulse at a repetition rate of 1Hz. In order to provide this power, a Thales TH116 triode, driven by a Burle 4616 tetrode is used, with each amplifier chain providing ~2.5MW. This power is then split between 2 cavities. The complete MICE RF system is described, including details of the low level RF, the power amplifiers and the coaxial power distribution system. Testing of the amplifier chain, power supplies and low level RF is described.
CLS, Saskatoon, Saskatchewan
Upgrades to the orbit control system at the Canadian Light Source (CLS) have resulted in increased beam stability and reproducibility. These upgrades include improving position information from the beam position monitors (BPMs) by modifying the data acquisition algorithm and switching to a real-time operating system. Beam motion has been reduced to an RMS deviation of less than 1 micron in both planes. Limiting the maximum corrector step has allowed the use of all singular values when inverting the BPM response matrix, resulting in much better orbit reproducibility. As well, improved lookup tables have been developed to compensate for the effects of changing undulator gaps and polarizations. Presently, work is underway to develop fast orbit correction with rates up to 100 Hz. Fast orbit correction will further reduce the residual perturbations caused by undulator activity and will allow fast ramping of superconducting wigglers.
LSU/CAMD, Baton Rouge, Louisiana
To control the emittance coupling in the CAMD Light Source, new power supplies have been constructed which adjust the currents in the individual coils of the normal lattice sextupoles, thereby creating skew quadrupole fields. The new power supplies add or subtract current through the pre-energized coils. Performance contributing factors include a summing network with a temperature coefficient less than 1ppm/°C, a water cooled resistive shunt, and linear optical signal isolation. High density & modularity control boards and water cooled power cards are mounted as pull-out units in a 19” rack. Active limiters and fault indicators can provide reliability and portability to higher power designs. The use of these skew quadrupoles in controlling and minimizing the emittance coupling is presented.
FZJ, Jülich
BINP SB RAS, Novosibirsk
The design, construction and installation of a 2 MeV electron cooling system for COSY-Jülich is proposed to further boost the luminosity even with strong heating effects of high-density internal targets. In addition the 2 MeV electron cooler for COSY is intended to test some new features of the high energy electron cooler for HESR at FAIR in Darmstadt. The design of the 2 MeV electron cooler will be accomplished in cooperation with the Budker Institute of Nuclear Physics in Novosibirsk, Russia. A new developed prototype of the high voltage section, consisting of a gas turbine, magnetic coils and high voltage generator with electronics was successfully tested . Special emphasis is given to a voltage stability better than 10-4. First experiments with three combined high voltage sections, arranged in a SF6 pressurized gas tank are reported.
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
J-PARC, KEK & JAEA, Ibaraki-ken
The painting injection of the 3-GeV RCS in J-PARC has been tested since May in 2008. The shift bump-magnets, which give a constant bump field in a horizontal plane during injection, comprise four magnets connected in series. However, the total integrated magnetic field over the four magnets is not zero because of the magnetic field interferences with the neighboring quadrupole magnets. So the gap of each magnet was adjusted by inserting thin insulators into the splitting plane of the side yoke so that the field integration becomes zero. The thickness was determined experimentally. The closed orbit distortion due to the field imbalances was then confirmed to be less than 1 mm. Another four paint bump-magnets are also necessary to give time-dependent fields. They are connected to their own power supplies, separately. The excitation of each magnet is calibrated by using the beam so that the created bump orbit satisfies the position and inclination at the injection point, and there are no orbit distortions outside the injection area. As for a vertical plane, a vertical paint magnet is located pi-radian upstream of the injection point to control the vertical angle of the beam.
ANL, Argonne
Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
The Circular Polarizing Undulator (CPU) had been used for about 10 years at the APS to generate X-rays with variable polarization (circular and linear) switching at rates up to 10 Hz. The CPU consists of two main coils with maximal currents 1600A (about 30kW power) and 400A (4kW power) and seven additional correcting coils. Aging and obsolescence of some of the CPU PS critical components resulted in deterioration of its performance and elevated maintenance. To resolve the issue and to comply with the new requirements for the beam stability at the APS storage ring, the new PS and control electronics for the CPU have been proposed. The new 8-channel Arbitrary Function Generator generating unique complex waveforms for the correctors to minimize orbit distortion during the main coils PS switching will also be discussed in this paper.
ANL, Argonne
Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
The APS storage ring uses DC/DC converters to power the magnets. High resolution for current regulation is desired for future improvement. It is calculated that at least 20- to 21-bit digital pulse width modulation (DPWM) is required in the proposed digital control system. This paper proposes a digital control system that adopts a new DPWM topology to achieve 21-bit DPWM without gigahertz system clock. The proposed topology uses a combination of a field-programmable gate array (FPGA) and a serializer chip TLK2541 from TI. The FPGA calculates the desired PWM signals and sends them to the TLK2541 chip. Then, the TLK2541 generates corresponding high-resolution DPWM pulses. An FPGA development board has been used to develop a prototype system to verify the proposed DPWM generation topology. This paper discusses the circuit topology and the experiment results.
BNL, Upton, Long Island, New York
The Brookhaven AGS Main Magnet Power Supply is a thyristor control supply rated at 5.5KAmps, ±9KV. The peak magnet power is 50MW,which is fed from a motor/generator manufactured by Siemens. During rectify and invert operation, the P Bank power supplies are used. During the flattops the F Bank power supplies are used. The P Bank power supplies are fed from two 23MVA transformers and the F Bank power supplies are fed from two 5.3 MVA transformers. The fundamental frequency of the F Bank power supplies is 1440Hz while the P banks were 720Hz. It was very important to reduce the ripple during rectify to improve polarized proton operations. For this reason and also because the original transformers were 45 years old we replaced these transformers with new ones and we made the fundamental frequency of both P and F banks 1440 Hz. This paper will highlight the major hurdles that were involved during the installation of the new transformers. It will present waveforms while running at different power levels up to 6MW full load and show the transition from the F-Bank power supplies to the P-Banks and also show the improvements in ripple made on the P-Bank power supplies.
IHEP Beijing, Beijing
The 1.6GeV proton synchrotron proposed in the CSNS Project is a 25Hz rapid-cycling synchrotron (RCS) with 80MeV Linac. Beam power is aimed to 100kW at 1.6GeV. In this paper the designs of the prototype of DTL-Q power supply and the prototype of the resonant network with one mesh exciting in series will be introduced.
Fermilab, Batavia
Fermilab is in the process of upgrading its Booster Correction Element System to include full field correction element magnets to correct position and chromaticity throughout the booster cycle. From a reliability standpoint, it is important to limit both the maximum temperature and the repetitive temperature cycling of the silicon junctions of the switching elements. We will describe how we measured these parameters and the results of our measurements.
Fermilab, Batavia
Fermilab is in the process of upgrading its Booster Correction Element System to include full field correction element magnets to correct position and chromaticity throughout the booster cycle. This upgrade requires power supplies with maximum outputs of ±180V/±65A, with current bandwidths of 5kHz and with slew rates of min to max current in 1ms. For seamless operation around zero current and voltage, we use continuous switching on both sides of the bridge. Although the straightforward way of coordinating the switching on both sides of the bridge can be accomplished with one triangle timing wave and one voltage reference, we have found that using two triangle waves yields a switching coordination that effectively doubles the frequency of the differential ripple on the load and allows for better and cheaper filtering of the output ripple.
LBNL, Berkeley, California
Funding: This work was supported by the Director, Office of Science, U. S. Department of Energy under Contract No. DE-AC02-05CH11231.
The Advanced Light Source (ALS) is a third generation synchrotron light source that has been operating since 1993 at Berkeley Lab. Recently, the ALS was upgraded to achieve Top-Off Mode, which allows injection of 1.9GeV electron beam into the Storage Ring approximately every 30 seconds. Modifications required for Top-Off operation included replacing the booster dipole and quadrupole magnet power supplies to increase the peak booster beam energy from 1.5GeV to 1.9GeV. Each new power supply was originally controlled by an analog controller that performs the current feedback loop and, in concert with other modules in the control chassis, determines the output of the ramped power supply. The new digital power supply controller performs the current feedback loop digitally to provide greater output stability and resolution. In addition, it provides remote monitoring of feedback loop signals, interlocks, and status signals, as well as remote control of the power supply operation via Ethernet. This paper will present the ALS Digital Power Supply Controller module requirements and design.
NSRRC, Hsinchu
Corrector magnets of TLS storage ring are served with linear power supplies (corrector magnet power supplies), with some modifications the long-term output current stability and ripple of these linear power supplies were improved from 500 ppm to 50 ppm. But these linear power supplies are very low efficiency、low power factor and about 20Hz low frequency response bandwidth that waste power、noisy and unable to serve fast orbit correction. MCOR30 is a modular switching power converter with smaller volume、high efficiency and above 100Hz frequency response bandwidth, replacing these linear power supplies with MCOR30s that could save power and increasing orbit correction response.
NSRRC, Hsinchu
The Agilient 6682A power supply is used as a dipole magnet power supply of Booster to storage ring (BTS) transport line, its output current stability is less than 100 ppm although specification is 1000 ppm. The performance of Agilient 6682A is quite good for TLS operational requirement but not suitable for less than 10 ppm output current stability general requirement of power supplies of TPS. Circuitry modification of Agilient 6682A to reach less than 10 ppm output current stability is hard to implement; but utilize analog programming function of Agilient 6682A with adding an external current control loop the output current stability of Agilient 6682A could be improved to less than 10 ppm.
NSRRC, Hsinchu
The purpose of this paper is to reduce the Electromagnetic Interference (EMI) from kicker and its pulsed power supply. Analysis of conducted and radiated EMI is the beginning mission. Different frequency range of radiated EMI was measured by different sensors. A hybrid shielding method was used to test reduction of radiated EMI. The copper and μ-metal enclosure was used on kicker magnet to prevent the radiated EMI. The reduction of electromagnetic field showed the effect of different material. Besides, the conducted EMI was also tested and eliminated by adding grounding routs. For decreasing grounding noise to other systems, the individual grounding bus was installed. The experimental results showed significant effect. In the future, TPS (Taiwan Photon Source) injection magnets will design higher performance, lower EMI than TLS (Taiwan Light Source). Therefore reducing and eliminating the interference of electromagnetic waves will be a very important issue. All the EMI prevention schemes will implement in the new project.
BINP SB RAS, Novosibirsk
DESY, Hamburg
Funding: This work was performed within the framework of the agreement between Deutsches Elektronen-Synchrotron (DESY, Hamburg) and BINP SB RAS (Russia, Novosibirsk), "Attachment N 18".
Power system for the klystron cathode heater power supply has been developed to transfer 800 Watts up to 130 kV potential based on the high-voltage gap transformer. Power transfer has been implemented resonant way on the frequency of 19.5 kHz using coupled LC-loops with further transformation to DC. Transformer coupling factor is of 0.58, high-voltage gap is 49 mm, and maximum calculated electric field intensity is 35 kV/cm. Primary winding is powered by the full bridge inverter using phase shifted pulse modulation. This inverter topology provides soft switching of the transistors in a wide range of power regulation (from 18 up to 800 Watts) without an auxiliary active resonant snubber circuits. High stability (0.3%) of the output power has been reached using proportional regulation in the feedback circuit. The achieved power conversion efficiency of inverter is more than 0.95 in the regulation range; efficiency of the whole power system is more than 0.88. The reliable operation of the power system is guaranteed on three types of klystrons (Toshiba E3736; Thales TH1801; CPI VKL8301). The work has been performed within the European XFEL project.
SLAC, Menlo Park, California
Funding: Work supported by the U.S. Department of Energy under contract number DE-AC02-76SF00515
This paper will report on the test results of a prototype 1320 watt power module for a high availability power supply. The module will allow parallel operation for N+1 redundancy with hot swap capability. The two quadrant output of each module allows pairs of modules to provide a 4 quadrant (bipolar) operation. Each module employs a novel 4 FET buck regulator arranged in a bridge configuration. Each side of the bridge alternately conducts through a small saturable ferrite that limits the reverse current in the FET body diode during turn off. This allows hard switching of the FETs with low switching losses. The module is designed with over-rated components to provide high reliability and better then 97% efficiency at full load. The modules use a Microchip DSP for control, monitoring, and fault detection. The switching FETS are driven by PWM modules in the DSP at 60 Khz. A Dual CAN bus interface provides for low cost redundant control paths. The DSP will also provide current sharing between modules, synchronized switching, and soft start up for hot swapping. The input and output of each module have low resistance FETs to allow hot swapping and isolation of faulted units.
STFC/RAL/ISIS, Chilton, Didcot, Oxon
Funding: ISIS
The Extracted Proton beam line for the ISIS second target station has two 10 Hz pulsed magnet systems and a DC Septum magnet system which extract the protons from the existing 50 Hz beam line. The pulsed Kicker 1 magnet system deflects the beam 12.1 mrad, pulsed Kicker 2 deflects the beam 95 mrad and the DC Septum magnet system deflects the beam 307 mrad. This paper describes the topology, installation, testing and successful operation of each of the power supplies.
ELETTRA, Basovizza
The New Full-Energy Injector at Elettra, based on a 3 Hz, 100 MeV to 2.5 GeV booster has officially started its operations since March 2008*. The time schedule was fully respected notwithstanding the performance problems presented by some of the main magnet power supplies**. The refurbishing plan, formally started at the end of the commissioning phase and carried on together with the manufacturer, has brought positive results in approaching the required specifications. The paper will describe the progress of the refurbishing and the experience with the other magnet power supplies, including the positive performances of the in-house low-current (5A) bipolar power supplies, especially designed for the linac pre-injector***. A new version, fully digitally controlled, of these low-power power supplies will be adopted for some coils and magnets of the FERMI@Elettra project.
*M. Svandrlik, Status of the Elettra Booster Project, EPAC08
**R. Visintini, Magnet power converters for the Elettra Booster, EPAC08
***D. Molaro, A new bipolar PS for the Elettra booster, PCIM08
ELETTRA, Basovizza
Funding: The work was supported in part by the Italian Ministry of University and Research under grant FIRB-RBAP045JF2
FERMI@Elettra is the new 4th-generation light source, based on a single-pass FEL, under construction at the Elettra Laboratory in Trieste, Italy. Some hundreds of magnets and coils need to be supplied along the accelerator sections and the undulators chains - mostly individually - with currents as low as 1.5 A up to 750 A. Starting from a successful design developed at Elettra* for the full-energy injector**, a new version of the existing 4-quadrant, 5 A PS has been studied. This new bipolar low-current PS, with full digital control, will be adopted for all 1.5 A and 5 A loads. The design of a bipolar PS for supplying the 20 A loads is in progress. This paper will describe the proposed PS system for the magnets and coils of FERMI@Elettra. The focus will be on the solutions adopted to minimize the number of different PS types. Particular stress will be laid upon the in-house design.
*D, Molaro et al. - A new bipolar power supply for Elettra booster pre-injector correctors - PCIM08
**R. Visintini et al. - Magnet power converters for the new Elettra full energy injector - EPAC08
Transtechnik, Holzkirchen
TT-MoPS Next Generation Modular Power Supply Transtechnik designed a new generation of a high flexible high current modular Power Supply. The target was to combine the experience of the CERN-LHC-Project with the requirements of the market and some new ideas. High reliability-best performance; Strongly modular-to meet a wide range of specifications; External calibration-fully automatically calibration without moving the rack installation; Easy to repair@module level-plug and play solution for high availableness; Easy to configure-Fast notation, fast implementation, easy maintainability; High accuracy-about 100ppm current regulation; For our customer STFC Rutherford Appleton Laboratories, Transtechnik produces a modular system for output voltage up to 125 VDC (CERN LHC-Product: 18V/±40V) and a current loading between 100 A and 500 A (CERN LHC-Product:13,5kA/21kA/600A). The system consists of with a new generation of standard Power Supply modules which allow combination of the shelf Power Supply to a customised Power Supply in a flexible and comfortable way(optional Modifikation:n+1 redundancy; un/-load module for high current inductors and high voltage modules-CEBU).
BNL, Upton, Long Island, New York
Funding: Work supported by Brookhaven Science Associates, LLC underContract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
In order to cross more rapidly the 82 weak resonances caused by the horizontal tune and the partial snakes, we plan to jump the horizontal tune 82 times during the acceleration cycle, 41 up and 41 down*. To achieve this, the magnets creating this tune jump will pulse on in 100 micro-seconds, hold the current flat for about four milli-seconds and zero the current in another 100 micro-seconds. The magnets are old laminated beam transport magnets with longitudinal shims closing the aperture to reduce inductance and power supply current. The power supply uses a high voltage capacitor discharge to raise the magnet current, which is then switched to a low voltage supply, and then the current is switched back to the high voltage capacitor to zero the current. The current in each of the magnet pulses must match the order of magnitude change in proton momentum during the acceleration cycle. The magnet, power supply and cabling will be described with coast saving features and operational experience.
*Overcome Horizontal Depolarizing Resonances in the AGS with Tune Jump
IHEP Beijing, Beijing
China Spallation Neutron Source is a high intensity beam facility planed to build in future in China. It is composed of Linac, RCS and target station. The beam extraction from the RCS will be realized by ten vertical kicker magnet and one Lambertson magnet. One prototype kicker magnet has been successfully designed and developed in Institute of High Energy Physics. In this paper, the physical and structural design of the prototype kicker magnet are presented, and issues of the magnet development, construction and test are discussed.
IHEP Beijing, Beijing
The prototype of pulsed power supply for injection painting bump magnets of CSNS/RCS is being developed. This pulsed power supply consists of IGBT H bridges in series and parallel. The pulse current of the prototype is 18000A, the voltage is about 3KV and the equivalent frequency is about 1MHz. This paper will introduce this prototype in detail.
CERN, Geneva
The goal of the present CLIC Test Facility (CTF3) is to demonstrate the technical feasibility of specific key issues in the CLIC scheme. The extracted drive beam from the combiner ring (CR), of 35 A in magnitude and 140 ns duration, is sent to the new CLic EXperimental area (CLEX) facility. A Tail Clipper (TC) is required, in the CR to CLEX transfer line, to allow the duration of the extracted beam pulse to be adjusted. Fours sets of striplines are used for the tail clipper, each consisting of a pair of deflector plates driven to equal but opposite potential. The tail clipper kick must have a fast field rise-time, of not more than 5 ns, in order to minimize uncontrolled beam loss. High voltage MOSFET switches have been chosen to meet the demanding specifications for the semiconductor switches for the modulator of the tail clipper. This paper discusses the design of the modulator; measurement data obtained during testing and operation of the tail clipper is presented and analyzed.
Fermilab, Batavia
Funding: Fermilab is operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
A fast kicker power supply has been designed for use in the Main Injector at Fermilab. The system will be used for controlled removal of unbunched beam created in the slip stacking process. A switch operating at 50 kV with a 3% to 97% rise time of less than 25 ns into a 50 Ω load is required. A thyratron and enclosure have been designed. A pulse length of 1.6 us is required so a cable pulse forming line is used. Results with and without a ferrite pulse sharpening line will be presented. The magnet is described in a companion paper.
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
The main circuit of the switching power supplies for the injection bump system is composed of multiple-connection of the IGBT assemblies. The element of the IGBT assembly, which is the power supply of the shift bump-magnets, is a type of 3300V-1200A and 6 kHz in elementary frequency. The power supply has the output performance of 20 kA / 6.6 kV. The synthetic frequency of the multiple-connection assemblies is over 48 kHz and the tracking error less than 1 % is proved. The beam commissioning test of long-term operation for about three-week was performed. The deviation of the exciting current from the programmed current pattern has been confirmed less than 1%. The peculiar characteristic of the pulse power supply has been obtained by the analysis on the frequency response of the exciting current and the magnetic field. In the FFT analytical result of the magnetic field, the peaks of 48 kHz and its higher harmonics that are related to the switching frequency was observed. The ground loop current and the voltage were also measured.
LBNL, Berkeley, California
Funding: *Work supported by the Director, Office of Science, Office of Basic Energy Sciences, Materials Science and Engineering Division, of the Department of Energy under contract No. DE-AC02-05CH11231.
ALS is the 1.9GeV third generation synchrotron light source which has been operating since 1993 at Berkeley National Lab. Our team is now working on the design of a new RF power source (replacement of the existing 320kW klystron with 4 IOT’s). In the new design the existing conventional crow-bar klystron protection system will be replaced with a fast disconnect switch. The switch will be constructed out of 16 high-voltage IGBT’s connected in series equipped with static and dynamic balancing system. The main advantage of using this new technology is faster action and virtually no stress for the components of the high voltage power supply. This paper will describe the hardware design process and the test results of the prototype switch unit.
SLAC, Menlo Park, California
Funding: Work supported by the Department of Energy under contract No. DE-AC02-76SF00515.
The design and installation of the Linac Coherent Light Source* at SLAC National Accelerator Laboratory has included the development of a kicker system for selective beam bunch dumping. The kicker is based on an LC resonant topology formed by the 50 uF energy storage capacitor and the 64 uH air core magnet load and has a sinusoidal pulse period of 400us. The maximum magnet current is 500 A. The circuit is weakly damped, allowing most of the magnet energy to be recovered in the energy storage capacitor. The kicker runs at a repetition rate of 120Hz. A PLC-based control system provides remote control and monitoring of the kicker via EPICS protocol. Fast timing and interlock signals are converted by discrete peak-detect and sample-hold circuits into DC signals that can be processed by the PLC. The design and experimental characterization of the systems is presented.
*http://ssrl.slac.stanford.edu/lcls/
SLAC, Menlo Park, California
Funding: Work supported by the U.S. Department of Energy under contract DE-AC02-76SF00515
Introduced by the U.S. Navy more than a decade ago*, the concept of Power Electronic Building Blocks (PEBBs) has been successfully applied in various applications. It is well accepted within the power electronics arena that this concept offers the potential to achieve increased levels of modularity and compactness. This approach is thus ideally suited for applications where easy serviceability and high availability are key, such as the ILC. This paper presents a building block approach for designing Marx modulators. First the concept of "bricks and buses" is briefly discussed. Then a PEBB-oriented design is presented for the basic Marx cell of a 32-cell Marx modulator to power an ILC klystron; 120 kV, 140 A, 1.6 ms pulses at a repetition rate of 5 Hz. Each basic Marx cell is composed of a main cell and a correction cell that compensates the main cell droop. The main cell has a stored energy of 2.1 kJ per Marx cell and the correction cell an additional 0.5 kJ. This design allows over 30% of the total stored energy in the Marx modulator, 84 kJ, to be delivered in the output pulse, 26.9 kJ, while keeping the droop within a ±0.5% range.
*T. Ericsen. 'Power Electronics Building Blocks - A systematic approach to power electronics.' In: Proceedings of Power Engineering Society Summer Meeting, Seattle, WA, 16-20 July 2000.
Tsukuba University, Ibaraki
A new concept of a fast magnetic kicker system - the bridged-T network lumped kicker - is proposed. The rise time is as fast as that of a transmission line kicker, while the input-impedance can be matched with a characteristic impedance of the pulse power supply. The proposed scheme is compared with several conventional schemes. The demonstration of this proposed scheme is also performed. The results show expected performances.
NSRRC, Hsinchu
The correction power supplies are working in the storage ring of NSRRC. They are required to output high quality and high performance current that is long-term stability and output current ripple are required to be under 100ppm. The storage ring consists of more than one hundred units of independence power supplies working together when beam current in 1.5GeV status. The power supplies also are all working under current mode. We just build a new conduction EMI (Electromagnetic Interference) and EMC (Electromagnetic Compatibility) measurement laboratory to measure and test the switching power supplies. That is AC to DC voltage bus source to supply for the switching correction power supply. Using the LISN to obtain conduction noise, it is high frequency voltage noise generated by the switching mode of power supply conduction noise. The current signal pass AC source impendence stabilize network LISN and spectrum analyzer will obtain the conduction noise. We can use a noise separator to separate common EMI noise and difference-mode EMI noise for EMI filtering design. The measurement result will be illustrated in the paper.
CERN, Geneva
Virtually all modern accelerator control systems are nowadays based on commercial-off-the-shelf products (VME crates, PLCs, SCADA systems, etc.), on Windows or Linux PCs, and on communication infrastructures using Ethernet and TCP/IP. Despite the benefits coming with this (r)evolution, these "modern" control systems and infrastructures usually completely lack adequate levels of robustness, resilience and security. Even worse, new threats are inherited, too: Worms and viruses spread within seconds via the Ethernet cable, and attackers are becoming interested in breaking into control systems. This talk will discuss the initial security risks, what precautions are needed to protect control systems against cyber threats and how to provide a secure environment without sacrificing operability.
BNL, Upton, Long Island, New York
Overview of the main factors determining machine availability. Comparison of availability issues and strategy for high energy colliders and accelerators, synchrotron light sources, and spallation neutron sources. Description of how machines can be designed for high availability and systems for high reliability.
KEK, Ibaraki
The J-PARC accelerator comprises a 400 MeV linac, a 3-GeV Rapid Cycling Synchrotron (RCS) and a Main Ring (MR). In the linac, an H- ion beam was successfully accelerated to 181 MeV, the design target for the first step in Phase I, on January 24, 2007. Subsequently, full beam energy of 3 GeV was achieved in the RCS on October 31, 2007. The first beam commissioning of the MR was carried out in May and June 2008. Injection, circulation with rf capture and extraction to the injection beam dump were successfully performed. Some other basic tunings such as COD correction and chromaticity correction were also done well. In the MR, there are two extraction sections. One is for the Hadron Experimental Facility for which slow extraction will be mainly used and the other for neutrino experiment, which requires fast beam extraction. After confirming the basic performance of beam injection and beam circulation with rf capture, we have installed all devices for these two extraction sections and have progressed fine-tuning of ramp-up patterns of power supplies. Beam acceleration will start from December 2008. The first result of beam acceleration and extraction will be reported.
SAGA, Tosu
Kyoto IAE, Kyoto
The procedure of accelerator modeling using orbit response matrix fitting is well known and widely adopted at many light sources, we also examined the model fitting to diagnose optics and to restore the periodicity of the storage ring optics. In the modeling procedure we used the tracking code TRACY2, because it can calculate the orbit response matrix including energy offset caused by the dipole kick. The multi-parameter fitting was carried out by using SVD algorism implemented in the Labview mathematical package. In the fitting procedure, we fixed a steering magnet field to the value obtained from the orbit measurement using screen monitor to avoid explicit solution between the steering strengths and the BPM gains. By adopting the orbit response matrix fitting, it was found that the quadrupole strength is about 3-5% larger than the calculated value obtained from magnetic measurement data and output current of the power supply. In the conference, we will report on the result of the modeling procedure and its application to the optics correction.
ELETTRA, Basovizza
A full energy injector consisting of a 100 MeV linac and an up to 2.5 GeV booster is in operation since March 2008 replacing the previous 1 GeV linac injector to be used after refurbishing and upgrade for the new fourth generation light source (FEL) currently under construction at Sincrotrone Trieste. The measurements on the new injector, problems and solutions employed to increase its efficiency, reproducibility and reliability, aiming towards top-up operations in the near future, and its impact on the Elettra storage ring are presented and discussed.
ELETTRA, Basovizza
CELLS-ALBA Synchrotron, Cerdanyola del Vallès
Two variable polarization undulators have been designed and constructed as a Collaboration between CELLS and Sincrotrone Trieste*. In this paper the main magnetic and mechanical feature are summarized. Field optimization techniques are described, showing the achieved performance in terms of phase, trajectory and field integral errors.
*D.Zangrando et al. Design of two variable polarization undulators for the ALBA project, EPAC 2008, Genova, Italy
SOLEIL, Gif-sur-Yvette
A new electromagnetic/permanent magnets helical undulator, with a 65 mm magnetic period is under development at SOLEIL for providing a rapid switching of the photon polarization required to perform dichroïsm experiments. The vertical field will be produced by coils fed by a fast switching power supply, with a maximum current of 350 A and a polarity switching time shorter than 100ms. The coils consist of copper sheets cut by water jet method. 26 layers of copper will be stacked together while 10 of them will be water cooled. The current-regulated power supply should be able to operate in the 4 quadrants with a 50 ppm current resolution over the full scale. The design of this home made power supply will be described. The horizontal field will be generated by NdFeB permanent magnets. The design vertical and horizontal peak field values in the helical configuration are 0.24 T at the minimum 15.5 mm gap. The magnetic design and the correction scheme will be described. A prototype was built to characterise and validate the technical choices, and the results will be discussed. The efficiency of the cooling system and the results of the magnetic measurements will be presented.
BNL, Upton, Long Island, New York
Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
There is significant interest in RHIC heavy ion collisions at center of mass energies of 5-50 GeV/u, motivated by a search for the QCD phase transition critical point. The low end of this energy range is nearly a factor of four below the nominal RHIC injection center of mass energy of 19.6 GeV/u. There are several operational challenges in the low-energy regime, including harmonic number changes, longitudinal acceptance, magnet field quality, lattice control, and luminosity monitoring. We report on the results of beam tests with protons and gold in 2007–9, including first RHIC operations at √{(sNN)=9.2} GeV and low-energy nonlinear field corrections at √{(sNN)=5} GeV.
SLAC, Menlo Park, California
INFN/LNF, Frascati (Roma)
Funding: Work supported by the Department of Energy under contract number DE-AC03-76SF00515.
We present a possible design for a fast luminosity feedback for the Super-B Interaction Point (IP). The design is an extension of the fast luminosity feedback installed on the PEP-II accelerator. During the last two runs of PEP-II and BaBar (2007-2008), we had an improved luminosity feedback system that was able to maintain peak luminosity with faster correction speed than the previous system. The new system utilized fast dither coils on the High-Energy Beam (HEB) to independently dither the x position, the y position and the y angle at the IP, at roughly 100 Hz. The luminosity signal was then read out with three independent lock-in amplifiers. An overall correction was computed based on the lock-in signal strengths and beam corrections for position in x and y and in the y angle at the IP were simultaneously applied to the HEB. With the 100 times increase in luminosity for the SuperB design, we propose using a similar fast luminosity feedback that can operate at frequencies between DC and 1 kHz, high enough to be able to follow and nullify any vibrational beam motion from the final focusing magnets.
Sokendai, Ibaraki
KEK, Ibaraki
Toyobo Research Institute, Shiga
Main cause of premature quench in superconducting magnet is the heat generated due to sudden superconducting wire motion. The wire motion occurs where electromagnetic force to conductors exceeds frictional force on surfaces of the conductors. Hence, frictional properties of the conductors and winding structures are important parameters for characterizing stability of the superconducting windings. Experiments were carried out to detect the superconducting wire motion under the influence of varying electromagnetic force. The wire movement is detected by observing the spike in voltage of the superconducting sample wire. From the time profile of voltage spike, distance moved by superconducting wire is estimated. Insulating material such as Dyneema random sheet, Dyneema non-woven sheet and Dyneema fiber cloth were used at the interface of superconducting wire and base material. Dyneema has low frictional coefficient and negative thermal expansion. The experimental findings will be discussed.
IHEP Beijing, Beijing
CSNS accelerator mainly consists of an H- linac and a proton rapid cycling synchrotron. It is designed to accelerate proton beam pulses to 1.6 GeV kinetic energy at 25 Hz repetition rate, striking a solid metal target to produce spallation neutrons. The accelerator is designed to deliver a beam power of 120 kW with the upgrade capability up to 500 kW, The CSNS accelerator is the first large-scale, high-power accelerator project to be constructed in China and thus we are facing a lot of challenges in some key technologies. A series of R&D for major prototypes have being conducted since 2006, including an H- ion source, DTL tank, RF power supply for the linac, injection/extraction magnets and its pulse power supplies, dipole and quadrupole prototype magnets in the ring and its power supplies, ferrite-loaded RF prototype cavity, ceramic vacuum chamber, control and some beam diagnostics. This paper will briefly introduce the design and R&D status of the CSNS accelerator.
BNL, Upton, Long Island, New York
We investigate AC response of accelerator vacuum chambers to external magnetic field, when the wall thickness is comparable or greater than the skin depth. Good agreement was established between experimental measurements, analytical modeling, and ANSYS simulations. Based on the results we suggest a transfer function model for electrically thick vacuum chambers with arbitrary transverse cross-section.
ANL, Argonne
Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract No. DE-AC02-06CH11357.
The Advanced Photon Source (APS), a third-generation synchrotron light source, has been in operation for eleven years. The monopulse radio frequency (rf) beam position monitor (BPM) is one of three BPM types now employed in the storage ring at the APS. It is a broadband (10 MHz) system designed to measure single-turn and multi-turn beam positions, but it suffers from an aging data acquisition system. The replacement BPM system retains the existing monopulse receivers and replaces the data acquisition system with high-speed analog-to-digital converters (ADCs) and a field-programmable gate array (FPGA) that performs the signal processing. The new system has been installed and commissioned in a full sector of the APS. This paper presents the results of testing of the beam position monitor which is now fully integrated into the storage ring orbit control and fast feedback systems.
LNLS, Campinas
UNICAMP, Campinas, São Paulo
This paper reports on the LNLS experience with the digital electron beam position monitor Libera Brilliance through the realization of several standard accelerator physics experiments, taking advantage mainly of the equipment’s turn-by-turn capabilities.
CIAE, Beijing
The beam phase monitor was designed to address phase slide issue, which can lead to significant beam loss inside 100MeV cyclotron. The measured phase information can be used to direct cyclotron magnetic field fine tuning. The system describes in this paper consists of the following part: 10 sets of beam phase pickup, a phase detector, a set of RF multiplexer and a phase shifter to compensate different phase offset generated by cables, connectors etc. The last one is a computer interface consisting of two 16 bits AD converters, one ARM 7 processor was included in this module to support RS232 connection and perform necessary signal process. All parts except the probe were located in one 3U VME standard crate, 8 slots were occupied and one user defined backplane was developed to carry necessary power supply lines and inter-connections. Preliminary tests for the electronic system has been performed, and a good result was obtained in the procedure. Yet the leakage from RF cavity in the 100MeV cyclotron is still an undermined limitation for this application.
ANL, Argonne
Funding: This work was supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CHlI357.
During an operating period in which a sextupole unknowingly connected with the wrong polarity resulted in reduced beam lifetime, a list of machine physics experiments and simulations were developed to identify possible gradient errors of one or more sextupole magnets. We tried tune dependence on orbit, response matrix measurements at different momenta, sector-wise chromaticity measurements, empirical search with sextupole harmonics, and guidance from tracking simulations. The practicality of each will be discussed.
BNL, Upton, Long Island, New York
Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The Booster to AGS (BtA) transfer line was designed to match both ions and protons into the AGS lattice. For proton beam operation the only constraint on the optics is to define a match to the AGS lattice. For ions operation there are constraints introduced by a stripping foil in the upstream part of the transfer line. For polarized proton operation there is the complication that the lattice to match into in the AGS is distorted by the presence of two partial snake magnets. In the 2008 polarized proton run it was observed that there was an optical injection mismatch. Beam experiments were conducted that showed disagreement with the model. In addition, these studies revealed some minor problems with the instrumentation in the line. A new model and more reliable measurements of the transfer line magnet currents have been implemented. Another series of experiments were conducted to test these modifications and to collect a more complete set of data to allow better understanding of the beam dynamics during the transfer and better understanding of the instrumentation. In this paper we will present the results of these experiments and comparison to the new model of the BtA.
NSRRC, Hsinchu
Since the diagnostic system built with the new BPM system upgrade in TLS, we can observe and analyze the orbit stability more clearly and systematically. The disturbances to cause orbit fluctuation mainly come from power supply ripple, ground vibration, ID effects and etc. Removing the disturbed source is a straight, effective but inactive solution. Orbit feedback system is therefore adopted to suppress the remaining noise. In this report, we will evaluate the orbit stability in TLS and present the efforts we have done to improve the orbit stability.
NSRRC, Hsinchu
The orbit feedback system of the TLS has been deployed for a decade to stabilize electron closed orbit. As the upgrades of digital bpm electronics and switching power supply, the infrastructure of orbit feedback system has also been dramatically modified and rebuilt. The most primary works for the upgrade plan have been done including installation of new bpm and power supply since it was first proposed. After the ordered computer blade ready and the current updated rate raised from 1 kHz to 5 kHz or even 10 kHz, the system will evolve to a newly fast orbit feedback system. It is new scheduled to be commissioned in 2009 spring and can be expected to achieve a submicron stability of the electron beam at a bandwidth of at least 60 Hz.
SSRF, Shanghai
Funding: SSRF
The ssrf is a 3rd generation light source under commissioning. The commissioning of the storage ring has progressed very well so far. The periodicity and symmetry of the linear optics in a real storage ring is important, however maybe be broken by various errors, such as field errors, manufactured errors. A distorted linear optics can excite stronger nonlinear resonances, which will reduce the storage ring dynamic aperture and make the storage ring suffer from low injection efficiency and short beam lifetime. Therefore, it is necessary to restore the designed periodicity or symmetry of the linear optics based on measured closed orbit distortion. The calibration procedure can be done by using LOCO (the Linear Optics from Closed Orbit). After fitting the measured response matrix by the model one, the linear optics of the storage ring is calibrated. And different operation modes have been also measured and calibrated.
BNL, Upton, Long Island, New York
LBNL, Berkeley, California
Funding: U.S. Department of Energy
A new approach to embedded device control is being developed by Lawrence Berkeley Laboratory (LBNL) and Brookhaven National Laboratory (BNL). Synchronous device interface (SDI) will be implemented in NSLS-II project as a key communication protocol. This paper describes the design motivation and principles of SDI. It also discusses SDI in fast orbit feedback system and its extension in power supply control system.
SLAC, Menlo Park, California
Funding: Work supported by US DOE
For LCLS, an uptime of 95% of the scheduled beam time is aimed for. This is a challenging goal for a linac-driven facility, exceeding typical up time during PEP-II running by a significant amount. During the 2008 and the 2009 LCLS beam-commissioninng runs we have been gathering and analysing statistics to identify the worst offenders as far as downtime is concerned. In 2008, an overall hardware uptime of 90% was achieved, indicating the need to decrease our downtime by a factor of two. One approach to focus the effort has been to identify those faults that cause the worst performance for a system in a given time period and focus on these. Another one is to compare our MTTR performance with that of other facilities thus identifying where our processes might be improved. In this paper we will show how we track our performance and examples of the benefit of addressing identified reliability issues.