THOB —  Machine parameters measurement   (13-Sep-18   11:00—12:30)
Chair: C. Kim, PAL, Pohang, Kyungbuk, Republic of Korea
Paper Title Page
THOB01 Injection Transient Study Using 6-Dimensional Bunch-by-bunch Diagnostic System at SSRF* 542
 
  • Y.M. Zhou, Y.B. Leng, N. Zhang
    SSRF, Shanghai, People's Republic of China
  • B. Gao
    SINAP, Shanghai, People's Republic of China
 
  Beam instability often occurs in the accelerator and even causes beam loss. The beam injection transient process provides an important window for the study of beam instability. Measurement of the bunch-by-bunch dynamic parameters of the storage ring is useful for accelerator optimization. A 6-dimensional bunch-by-bunch diagnostic system has been successfully implemented at SSRF. The measurements of transverse position and size and longitudinal phase and length are all completed by the system. Button BPM is used to measure beam position, phase, and length, and the synchrotron radiation light is used to beam size measurement. Signals are sampled simultaneously by a multi-channel acquisition system with the same clock and trigger. Different data processing methods are used to extract the 6-dimensional information, where the delta-over-sum algorithm for beam position extraction, the Gaussian fitting algorithm for beam size extraction, zero-crossing detection algorithm for beam phase extraction and the two-frequency method for bunch length extraction. The system set up and performance will be discussed in more detail in this paper.  
slides icon Slides THOB01 [7.413 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-THOB01  
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THOB02 Energy Loss Measurements with Streak Camera at ALBA 548
 
  • A.A. Nosych, B. Bravo, U. Irisopresenter
    ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
 
  Analyzing streak camera images of the beam injected into a Storage Ring with no RF voltage allows calculating several parameters, like the energy loss per turn and the energy mismatch between injected and stored beams. These measurements are based on the analysis of the centroid drift path of a bunch as it spirals inwards, changing its rotation period. This drift is clear and measurable in single and multi-bunch modes in several horizontal sweep speeds of the streak. With this technique we also measure the momentum compaction factor and observe its change with respect to the insertion devices' open/closed states. The obtained values are comparable with theoretical expectations, as well as with values measured by other means.  
slides icon Slides THOB02 [3.030 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-THOB02  
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THOB03 Long Term Investigation of the Degradation of Coaxial Cables 552
 
  • M. Kuntzsch, R. Schurig
    HZDR, Dresden, Germany
  • S.J. Burger
    Delta Gamma RF-Expert, Melbourne, Australia
  • T. Weber
    el-spec GmbH, Geretsried, Germany
 
  For the transport of RF signals coaxial cables with PTFE ('Teflon') as dielectric medium are widely used because they offer a wide bandwidth and low insertion loss. Coaxial cables that are routed in immediate vicinity to the beamline are exposed to ionizing radiation that is mainly generated by beam-loss. In this radiative environment cables change their electrical properties which directly affects the signal on the receiver side and in turn the measured beam parameters. This contribution describes a measurement setup at the superconducting CW accelerator ELBE that was used to investigate the degradation of coaxial cables under well-controlled conditions up to an accumulated dose of 94 kGy. Furthermore the acquired data up to 40 GHz of two coaxial cable samples are presented and the results are discussed.  
slides icon Slides THOB03 [6.958 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-THOB03  
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