TUPB —  Tuesday Poster B   (11-Sep-18   16:00—17:30)
Paper Title Page
TUPB01 The Installation and Commissioning of the AWAKE Stripline BPM 253
  • S. Liu, P.E. Dirksen, V.A. Verzilov
    TRIUMF, Vancouver, Canada
  • S.J. Gessner, F. Guillot-Vignot, D. Medina, L. Søby
    CERN, Geneva, Switzerland
  Funding: # TRIUMF contribution was supported by NSERC and CNRC
AWAKE (The Advanced Proton Driven Plasma Wakefield Acceleration Experiment at CERN) stripline BPMs are required to measure the position of the single electron bunch to a position resolution of less than 10 µm rms for electron charge of 100 pC to 1 nC. This paper describes the design, installation and commissioning of a such BPM system developed by TRIUMF (Canada). Total 12 BPMs and electronics had been installed on AWAKE beam lines and started commissioning since Fall of 2017. The calibration and measurement performance are also reviewed.
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-TUPB01  
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TUPB02 Complete Test Results of New BPM Electronics for the ESRF New LE-Ring 257
  • K.B. Scheidt
    ESRF, Grenoble, France
  Among the 320 BPMs in the ESRF new low emittance ring, a set of 128 units will be equipped with new electronics, while the other set (192) will be served by the existing Libera-Brilliance electronics. These new electronics are an upgraded version of the low-cost Spark electronics originally developed 3 years ago for the ESRF Injector complex. All these 128 units have been installed in the first half of 2018 on existing BPM signals (through duplication with RF-splitters) and subsequently been tested thoroughly for performance characteristics like stability, resolution and reliability. It will be shown that while these Sparks have a very straightforward and simple concept, i.e. completely omitting calibration schemes like RF-cross-bar switching, pilot-tone introduction or active temperature control, that they are fully compatible with all the beam position measurement requirements of this new ring.  
poster icon Poster TUPB02 [1.577 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-TUPB02  
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TUPB03 Results of SPIRAL2 Beam Position Monitors on the Test Bench of the RFQ 261
  • M. Ben Abdillah, P. Ausset
    IPN, Orsay, France
  • R. Ferdinand
    GANIL, Caen, France
  SPIRAL2 project is based on a multi-beam superconducting LINAC designed to accelerate 5 mA deuteron beams up to 40 MeV, proton beams up to 33 MeV and 1 mA light and heavy ions (Q/A = 1/3) up to 14.5 MeV/A. The accurate tuning of the LINAC is essential for the operation of SPIRAL2 and requires measurement of the beam transverse position, the phase of the beam with respect to the radiofrequency voltage, the ellipticity of the beam and the beam energy with the help of Beam Position Monitor (BPM) system. The commissioning of the RFQ gave us the opportunity to install two BPM sensors, associated with their electronics, mounted on a test bench. The test bench is a D-plate fully equipped with a complete set of beam diagnostic equipment in order to characterize as completely as possible the beam delivered by the RFQ and to gain experience with the behavior of these diagnostics under beam operation. This paper addresses the measurements carried with the two BPMs on the Dplate: energy, transverse position and ellipticity under 750 KeV proton beam operation  
poster icon Poster TUPB03 [1.443 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-TUPB03  
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TUPB04 Development of a New Button Beam-position Monitor for BESSY VSR 265
  • J.G. Hwang, V. Dürr, M. Ries, A. Schälicke, G. Schiwietz, D. Wolk
    HZB, Berlin, Germany
  An extreme operation mode such as the BESSY-VSR conditions stimulates the development of a high accuracy bunch-by-bunch beam-position monitor (BPM) system which is compatible with the bunch-selective operation for the orbit feedback system. Such a system will also greatly benefit to accelerator R&D such as transverse resonance island buckets (TRIBs). Compensation of the long-range ringing signal produced by the combined effect of impedance mismatching inside the button and trapped TE-modes in the aluminum-oxide insulator (Al2O3) material is required essentially to improve the resolution. This is important since the ringing causes a misreading of the beam position and current of following bunches. We show the design study of a new button-type BPM to mitigate the influence of the ringing signal as well as to reduce wake losses by improving the impedance matching in the button and by replacing the insulator material.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-TUPB04  
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TUPB05 Design of a Cavity Beam Position Monitor for the ARES Accelerator at DESY 269
  • D. Lipka, M. Dohlus, M. Marx, S. Vilcins, M. Werner
    DESY, Hamburg, Germany
  The SINBAD facility (Short and INnovative Bunches and Accelerators at DESY) is foreseen to host various experiments in the field of production of ultra-short electron bunches and novel high gradient acceleration techniques. The SINBAD linac, also called ARES (Accelerator Research Experiment at SINBAD), will be a conventional S-band linear RF accelerator allowing the production of low charge (within a range between 0.5 pC and 1000 pC) ultra-short electron bunches. To detect the low charge bunches a cavity beam position monitor is designed based on the experience from the EU-XFEL. It will consist of a stainless steel body with low Q factor of 70, a resonance frequency of 3.3 GHz and a relative wide gap of 15 mm to reach a high peak position sensitivity of 4.25 V/(nC mm). The design considerations and simulation results will be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-TUPB05  
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TUPB07 Stability Study of Beam Position Measurement Based on Higher Order Mode Signals at FLASH 273
  • J.H. Wei
    USTC/NSRL, Hefei, Anhui, People's Republic of China
  • N. Baboi
    DESY, Hamburg, Germany
  • L. Shi
    PSI, Villigen PSI, Switzerland
  FLASH is a free-electron laser driven by a supercon-ducting linac at DESY in Hamburg. It generates high-brilliance XUV and soft X-ray pulses by SASE (Self Amplified Spontaneous Emission). Many accelerating cavities are equipped with HOMBPMs (Higher Order Mode based Beam Position Monitors) to align the beam and monitor the transverse beam position. However, these lose their position prediction ability over time. In this paper, we applied an efficient measurement and signal analysis with various data process methods including PLS (Partial Least Square) and SVD (Singular Value Decomposition) to determine the transverse beam position. By fitting the HOM signals with a genetic algorithm, we implemented a new HOMBPM calibration procedure and obtained reliable beam prediction positions over a long time. A stable RMS error of about 0.2 mm by using the spectra of signals and 0.15 mm by using the new method over two months has been observed.  
poster icon Poster TUPB07 [1.816 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-TUPB07  
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TUPB09 The Evaluation of Beam Inclination Angle on the Cavity BPM Position Measurement 278
  • J. Chen, L.W. Lai, Y.B. Leng, L.Y. Yu, R.X. Yuan
    SINAP, Shanghai, People's Republic of China
  Cavity beam position monitor (CBPM) is widely used to measure the transverse position in free-electron laser (FEL) and international linear collider (ILC) facilities due to the characteristic of high sensitive. In order to study the limiting factors of the position resolution of cavity BPM, the influence of beam inclination angle on the measure-ment of CBPM position and the direction of beam deflec-tion was analyzed. The simulation results show that the beam inclination angle is an important factor limiting the superiority of CBPM with extremely high position resolu-tion. The relative beam experiments to change the relative inclination angle between the cavity and the electron beam based on a 4-dimension moveable platform were performed in Shanghai Soft X-ray FEL (SXFEL) facility, the experiment results will also be mentioned as well.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-TUPB09  
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TUPB10 Design and Simulation of Stripline BPM for HUST Proton Therapy Facility 281
  • J.Q. Li, Q.S. Chen, K. Fan, K. Tang, P. Tian
    HUST, Wuhan, People's Republic of China
  Proton beams used in Huazhong University of Science and Technology Proton Therapy Facility(HUST-PTF)have extreme low currents of the order of nanoampere,which is a great challenge to beam diagnostics due to low signal level. Conventional destructive beam diagnostic devices will affect the quality of the beam and cannot work online during the patient treatment, so a non-destructive stripline beam position monitor (BPM) is designed. This study will introduce some analysis and simulation results of the stripline BPM, such as the coupling between the electrodes, impedance matching, signal response, etc. We also discussed how to increase the output signal by geometry optimization.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-TUPB10  
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TUPB12 Machine Studies with Libera Instruments at the SLAC Spear3 Accelerators 284
  • S. Condamoor, W.J. Corbett, D.J. Martin, S. C. Wallters
    SLAC, Menlo Park, California, USA
  • M. Cargneluttipresenter, P. Leban
    I-Tech, Solkan, Slovenia
  • L.W. Lai
    SSRF, Shanghai, People's Republic of China
  • Q. Lin
    Donghua University, Shanghai, People's Republic of China
  Turn-by-turn BPM readout electronics were tested on the SPEAR3 booster synchrotron and storage ring to identify possible improvements for the booster injection process and to characterize processor performance in the storage ring. For this purpose, Libera Spark and Libera Brilliance+ instruments were customized for the booster (358.4 MHz) and storage ring (476.3 MHz) radio-frequencies, respectively, and tested during machine studies. Even at low single-bunch booster beam current, the dynamic range of the Libera Spark readout electronics provided excellent transverse position measurement capability during the linac-to-booster injection process, the energy ramp-up phase and during beam extraction. Booster injection efficiency was also analyzed as a function of linac S-band bunch train arrival time. In the SPEAR3 storage ring turn-by-turn Libera Brilliance+ measurement capability was evaluated for single and multi-bunch fill patterns as a function of beam current. The single-turn measurement resolution was found to be better than 10 microns for a single 3 mA bunch. The horizontal single-bunch damping time was then determined with the 238 MHz bunch-by-bunch feedback system on and off.  
poster icon Poster TUPB12 [1.531 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-TUPB12  
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TUPB13 Stability Tests with Pilot-Tone Based Elettra BPM RF Front End and Libera Electronics 289
  • M. Cargnelutti, P. Leban, M. Žnidarčič
    I-Tech, Solkan, Slovenia
  • S. Bassanese, G. Brajnik, S. Cleva, R. De Monte
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  Long-term stability is one of the most important properties of the BPM readout system. Recent developments on pilot tone capable front end have been tested with an established BPM readout electronics. The goal was to demonstrate the effectiveness of the pilot tone compensation to varying external conditions. Simulated cable attenuation change and temperature variation of the readout electronics were confirmed to have no major effect to position data readout. The output signals from Elettra front end (carrier frequency and pilot tone frequency) were processed by a Libera Spark with the integrated standard front end which contains several filtering, attenuation and amplification stages. Tests were repeated with a modified instrument (optimized for pilot tone) to compare the long-term stability results. Findings show the pilot tone front end enables great features like self-diagnostics and cable-fault compensation as well as small improvement in the long-term stability. Measurement resolution is in range of 10 nanometers RMS in 5 Hz bandwidth.  
poster icon Poster TUPB13 [1.223 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-TUPB13  
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TUPB14 New Beam Position Monitors for the CERN Linac3 to LEIR Ion Beam Transfer Line 293
  • L. Søby, G. Baud, M. Bozzolan, R. Scrivens
    CERN, Geneva, Switzerland
  The injection line into the CERN Low Energy Ion Ring (LEIR) has recently been equipped with nine, new, electrostatic Beam Position Monitors (BPMs) in order to measure and optimize the trajectory of the low intensity ion beams coming from LINAC3. In this paper, we describe the design of the BPM, the low noise charge amplifier mounted directly on the BPM, and the digital acquisition system. There is special emphasis on the first commissioning results where the measured beam positions were seen to be perturbed by EMI and charging of the BPM electrodes by secondary particles. The effect of mitigation measures, including repelling voltages on the electrodes and external magnetic fields, are also discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-TUPB14  
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