Paper | Title | Other Keywords | Page |
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MOPMF030 | Broadband Impedance of Pumping Holes and Interconnects in the FCC-hh Beamscreen | impedance, wakefield, coupling, injection | 153 |
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In the proposed Future Circular Collider (FCC-hh) pumping holes and interconnects between sections of the beamscreen can be sources of unwanted broadband impedance, potentially leading to the transverse mode coupling instability (TMCI). The pumping holes pose a greater challenge to the impedance calculation due to their small contribution per hole. Unlike for the Large Hadron Collider (LHC), analytical methods cannot be applied due to the complex beamscreen geometry and the greater size of the holes. Instead, two computational methods are used and compared to each other. For the interconnects, the impedance due to a sophisticated system of tapers is also estimated using computational methods. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF030 | ||
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WEPAF024 | Turn-by-Turn Position Measurements at CNAO with the Libera Spark HR Prototype | pick-up, hadron, instrumentation, electron | 1870 |
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CNAO in Pavia is one of the first centers for hadrontherapy in Europe, treating patients since 2011. The center is an international reference for a whole new concept of machines being constructed for this purpose. The synchrotron BPM electronics is based on analog boards that compute the ratio between difference and sum signals from the shoebox pickup, later acquired by digital cards. Although the system operates reliably, it just calculates the position with 1kHz rate, while the revolution frequency ranges from 0.5 to 3 MHz. To extend the measurement possibilities for these new hadron synchrotrons, Instrumentation Technologies is developing a data acquisition system capable of acquiring the pickup signals with 125MSps ADCs and calculating bunchbybunch positions of the accelerated beam. The first prototype was tested at CNAO: the turnbyturn beam position was analyzed off line, at different energies and positions with both Protons and Carbon ions beam. This paper will presents the results achieved with the system and compares them with the measurements of the current system. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF024 | ||
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WEPAF025 | Fast Intensity Monitor Based on Channeltron Electron Multiplier | electron, proton, high-voltage, detector | 1873 |
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The paper concerns the Fast Intensity Monitor (FIM) designed for the CNAO (Centro Nazionale di Adroterapia Oncologica), the Italian facility of Oncological Hadrontherapy. The FIM detector has been designed with the purpose of having a continuous and non-destructive measurement of the beam intensity in the High Energy Beam Transfer (HEBT) line. The passage of the beam through a thin aluminum foil produces secondary electrons whose yield depends on beam species (protons or carbon ions), intensity and energy. Secondary electrons are focused on the Channeltron Electron Multiplier (CEM) input, multiplied and sensed over a precision resistor. In order to minimize the perturbation to the beam, the foil is grounded and the read out electronics is floating. This makes electronics design harder but it is a key point to make FIM use possible continuously even during patients treatment. Measurements performed with the FIM are discussed and checked against reference detectors. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF025 | ||
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WEPAF046 | RF Electronics for the Measurement of Beam Induced Higher Order Modes (HOM) Implemented in the MicroTCA.4 Form Factor | HOM, cavity, dipole, electron | 1916 |
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Higher order modes (HOM) excited in RF accelerating cavities by a particle beam can be used for electron beam diagnostics. Phase of a monopole HOM provides information about the beam phase relative to the externally induced RF field in a cavity (BPhM) [1]. Furthermore, the amplitude of a dipole mode is proportional to the beam position in the cavity, hence it can be used for beam position monitoring (BPM). In this paper we present a prototype of an instrument implemented in the MicoTCA.4 form factor for the measurement of the HOMs at FLASH and Eu-XFEL. The prototype consists of an analog module, which is used for filtering and conditioning of the selected modes, and a digital module responsible for digitization and signal processing. We present the instruments performance and discuss its influence on the precision of the HOM-based diagnostics. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF046 | ||
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WEPAF048 | High Resolution and Low Charge Button and Strip-Line Beam Position Monitor Electronics Upgrade at Flash | electron, FEL, laser, operation | 1923 |
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Historically the FLASH (Free Electron Laser in Hamburg) facility at DESY (Deutsches Elektronen-Synchrotron) in Germany has foreseen operation in a charge range from 1nC-3nC for which a VME based BPM(Beam Position Monitor) system has been in operation since 2005. For a couple of years the standard machine operation has been settled at a few hundreds of pC with the tendency for smaller charges down to 100pC and smaller. The availability and resolution performance of the BPM system at charges below 300pC in many locations along the machine was unsatisfactory. In the last couple of years a new BPM electronic system based on the utca standard has been developed to overcome these limitations. A substantially improved version of the analog frontend and digital electronics has been developed in 2016 and tested successfully. During shutdown works at FLASH in summer 2017 all old button and strip-line BPM electronics has been replaced with the new type of electronics. This paper summarizes the features and performance of the new BPM system, compares the beam jitter free resolution of old and new BPM system and highlights its high single shot resolution of better than 10um at a charge of 15pC. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF048 | ||
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WEPAF049 | Energy Beam Position Monitor Button Array Electronics for the European XFEL | electron, FEL, vacuum, pick-up | 1927 |
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The European XFEL(X-Ray Free Electron Laser) at DESY(Deutsches Elektronen-Synchrotron) in Hamburg/Schenefeld started commissioning in early 2017. Before the pulsed electron beam is accelerated to its final energy of 14 GeV, the energy of the bunch can be compressed in three bunch compression chicanes at 130 MeV, 700 MeV and 2400 MeV. The vacuum chamber in these sections is tapered from 40 mm round beam pipe to a 40 cm rectangular shaped vacuum section. A custom made button array type of BPM(Beam position Monitor) is installed in this section with 26 button electrode feed-throughs. The analog and digital readout electronics for this monitor and the first experience with the calibration and operational aspects of this system are presented in this poster. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF049 | ||
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WEPAF059 | A Low Cost Beam Position Monitor System | pick-up, electron, hardware, target | 1961 |
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A Beam Position Monitor (BPM) system is essential to beam diagnostics for almost all particle accelerators. However, a typical BPM system contains customized hardware and complicated processing electronics which considerably drive the cost for large facilities where hundreds of them may be used. It also limits its use in the small scale accelerator facilities. In the paper, we present a low cost BPM system which consists of a commercial available CF flange based signal pickup device, a low cost integrated circuit adjacent to the pickup to filter, sample, digitize, and broadcast the signals out of the pickup electrodes. The digital signal is transmitted out for post processing through noise-protected Wi-Fi router. We will briefly discuss the working principle and experimental progress to date. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF059 | ||
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WEPAF085 | Upgrade of the CERN SPS Beam Position Measurement System | electron, pick-up, proton, FPGA | 2047 |
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The CERN Super Proton Synchrotron (SPS) is a fast cycling hadron accelerator delivering protons with momenta of up to 450 GeV/c for the Large Hadron Collider (LHC), fixed target experiments and other users such as the AWAKE plasma acceleration experiment, and also used to accelerate heavy ions. This paper presents the upgrade initiative for the SPS beam position measurement system in the frame of the CERN LHC Injector Upgrade (LIU) project. The new SPS beam position read-out electronics will be based on logarithmic amplifiers, using signals provided by the 216 existing beam position monitors, the majority of which are based on split-plane 'shoebox' technology. It will need to cover a dynamic range sufficient to manage the wide range of SPS beam intensities and bunch formatting schemes to provide turn-by-turn and averaged beam orbits along the SPS acceleration cycles. In order to avoid long coaxial cables, the front-end electronics including the digitisation, will be located inside the accelerator tunnel, with optical transmission to surface processing electronics. This represents an additional challenge in terms of radiation tolerance of electronics components and materials. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF085 | ||
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WEPAF088 | Machine Protection Features of the ESS Beam Current Monitor System | machine-protect, electron, interface, ion-source | 2058 |
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The BCM system of the European Spallation Source includes several machine protection features to ensure that the actual beam parameters will be consistent with the selected beam and destination modes. Differential current measurements with several ACCT pairs are foreseen to detect beam losses particularly in the low-energy linac where Beam Loss Monitors cannot be used. The ACCTs will also be used to check that no beam will be present in the sections downstream of a temporary beam dump. These measurements will then be used to stop the beam shortly after an abnormal condition has been detected by the BCM system. This will require some customized interfaces with the Timing System and the Machine Protection System as well as an optical interface for differential current measurement over large distances. Automatic setting of the machine protection thresholds and masking/unmasking of the interlocks based on the beam and destination modes are among the technical complexities. This paper gives an overview of the design including the most recent updates and discusses in more details the machine protection features of the BCM system. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF088 | ||
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WEPAK005 | A Cryogenic Current Comparators (CCC) Customized for FAIR-Project | niobium, pick-up, shielding, cryogenics | 2088 |
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The principle of non-destructive measurement of ion beams by detection of the azimuthal magnetic field, using low temperature Superconducting Quantum Interference Device (SQUID) sensors, has been established at GSI already in the mid 90's. After more recent developments at Jena, GSI and CERN, a CCC was installed in the CERN Antiproton Decelerator (AD) and is operated there routinely as the first stand-alone CCC system. For the Facility for Antiproton and Ion Research (FAIR) a new version of the CCC with eXtended Dimensions (CCC-XD) - especially with a larger inner diameter and adapted parameters - was constructed and first lab tests have already been performed. In parallel, a concept for a dedicated UHV beamline cryostat has been worked out. The CCC-XD system - together with the new cryostat - will be ready for testing in the CRYRING at GSI before the end of 2018. In this contribution, experimental results for the resolution, frequency range, slew rate and pulse-signal obtained by electrical laboratory measurements with the CCC-XD are presented. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAK005 | ||
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WEPAL012 | Measurements with the ELI-NP Cavity Beam Position Monitor Read-out Electronics at FLASH | electron, cavity, instrumentation, FEL | 2169 |
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The Extreme Light Infrastructure - Nuclear Physics Gamma Beam Source (ELI-NP GBS) will be installed and commissioned starting within the next year in Magurele, Romania. It will generate gamma beam through Compton back-scattering of a recirculated laser and a multi-bunch electron beam, produced by a 720 MeV LINAC. In order to obtain bunch by bunch position measurements, four cavity beam position monitors (cBPM) near the two interaction points are foreseen. Extensive tests on the cBPM read-out electronics, recently developed by Instrumentation Technologies and acquired for ELI-NP GBS, were performed in laboratory at INFN-LNF and at FLASH in DESY, during the user operation. In the latter case, three cBPMs installed along the LINAC, with similar features as the ones of ELI-NP GBS, were used as measuring devices and signal sources for the read-out electronics under test. We present here the measurements collected and the related analysis, with a particular focus on the beam position measurement resolution. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL012 | ||
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WEPML032 | The FAIR-SIS100 Bunch Compressor RF Station | cavity, power-supply, controls, coupling | 2759 |
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In the frame of the Facility for Antiproton and Ion Research (FAIR) 9 bunch compressor RF stations were ordered for the first stage of realization of the SIS100 synchrotron. For RF gymnastics referred to as bunch rotation, one RF station has to provide a sudden rise in gap voltage of up to 40 kVp within less than 30 μs. The system is designed for a maximum RF burst of 3 ms per second. The RF frequency will be pre-selectable between 310 kHz and 560 kHz at a harmonic number of h=2 with respect to the beam. Compressed bunches with a peak current > 150 A and a width < 50 ns are the goal. For this purpose, a 1.218 m long cavity was designed using iron-based magnetic alloy cores. Variable vacuum capacitors are attached for tuning. The cavity is driven by a cross-coupled push-pull tetrode amplifier. This scheme minimizes the influence of the tetrode's DC current at the working point to the cores. The energy for the pulsed system is stored in a relatively small capacitor bank which will be charged semi-continuously and a voltage-stabilizing device is added. Cavity and power amplifier were realized by AURION Anlagentechnik GmbH ' the power supply unit is designed and built by OCEM Power Electronics. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPML032 | ||
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THPAL062 | The New 20 kA 80 V Power Supply for the 520 MeV H− Cyclotron at TRIUMF | controls, power-supply, TRIUMF, software | 3792 |
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The new 20 kA, 80 V power supply for the main magnet of the 520 MeV H− Cyclotron at TRIUMF was awarded to OCEM. It has replaced the original system (commissioned in 1976) based on a series pass regulator. The final acceptance tests have demonstrated the com-pliance with the project specifications, especially for the high current stability required for the Cyclotron operation. The current stability is ±5 ppm, including current ripple, for a period of more than 8 hours of continuous operation. In addition, the magnetic field can be further stabilized us-ing feedback of a flux loop signal. OCEM designed the power supply to use the third gen-eration of Function Generator/Controller (FGC3) control electronics from CERN. This was chosen to obtain the high current stability required by TRIUMF. This collaboration was facilitated through a Knowledge Transfer agreement between CERN and OCEM. The power supply commis-sioning has been performed as a collaboration between OCEM, TRIUMF and CERN. This paper describes the topology of the power supply, the control electronics, the high-precision current measure-ment system and the associated software as well as the commissioning results carried out with the magnet. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL062 | ||
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THPAL083 | A Test Facility for Developments in Ion Source Plasma Power Supplies | power-supply, controls, plasma, ion-source | 3845 |
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A new test facility is being designed and constructed at the ISIS spallation neutron source, Rutherford Appleton Laboratory, for the purpose of developing and experimenting with new plasma power supply topologies and modes of operation. The test facility will allow better control of power supply parameters such as discharge pulse current and plasma ignition voltage along with the possibility for closed loop feedback control. The design and technical construction details are presented with an overview of the plasma power supply developments. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL083 | ||
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THPML112 | Preliminary Design and Calculation of Button BPM for the HALS Storage Ring | storage-ring, vacuum, HOM, impedance | 4929 |
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Funding: Supported by the National Science Foundation of China (Grant No.11705203, 11575181,11605202) and the National Key Research and Development Program of China(No. 2016YFA0402000) Button BPM is being designed for the HALS storage ring, which is a diffraction-limited storage ring (DLSR) located at the NSRL in Hefei city. Since beam size is very small, the required resolution of 50 nm for beam position measurement need to be obtained. The parameters of the HALS Button BPM are initially determined. According to theoretical formulas, electrode induced signal is calculated and the relationship between electrode induced signal and beam current is obtained. Signal to noise ratio(SNR)of the HALS Button BPM is calculated with different beam current when the required resolution is 50 nm. The results show that the SNR is well when beam current is very low. In addition, the effects of BPM RF frequency and button electrode radius on SNR are analyzed. |
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DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML112 | ||
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THPML115 | Introduction of the Laser Intensity Measurement System for the FELiChEM | laser, detector, FEL, electron | 4936 |
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The FELiChEM is a new infrared free electron laser (IR-FEL) facility, which is being built in the National Synchrotron Radiation Laboratory (NSRL) in Heifei, China. The facility will provide continuously tunable pulsed laser radiation covering the mid-infrared (MIR) wavelength range from 2.5 to 50μm and the far-infrared (FIR) range from 40 to 200μm. The output macro pulsed laser width is 5-10μs and pulsed laser power is 2-10kW. In order to evaluate pulsed laser saturation time and FEL optical cavity losses, the rise time and fall time of macro pulsed laser need to be measured. Laser intensity measurement system for the FELiChEM is being designed. This system is composed of optical system, pyroelectric detector and electronics. Each module will be described in detail in this paper. The laser intensity measurement system was tested under offline and online conditions. The results showed that pulsed laser of 10μs width can be measured and the design requirement can be met with this system. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML115 | ||
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