Author: Hwang, J.G.
Paper Title Page
MOCO04 Overview of Bunch-Resolved Diagnostics for the Future BESSY VSR Electron-Storage Ring 49
 
  • G. Schiwietz, J.G. Hwang, M. Koopmans, M. Ries
    HZB, Berlin, Germany
 
  The upgrade of the BESSY II light source in Berlin towards the Variable pulse-length Storage-Ring BESSY VSR will lead to a complex fill pattern. This involves co-existing electron bunches with significant variations of bunch-length, bunch charge as well as charge density. Among many other boundary conditions, this calls for bunch resolved measurements with sub-ps time resolution and micrometer spatial resolution. Currently, we are constructing a diagnostic platform connected to three new dipole beamlines for visible light as well as THz measurements. The mid-term aim is a 24/7 use of beam-diagnostic tools and the development of advanced methods for specific purposes. Recently, we have set-up a sub-ps streak camera* and we are investigating other innovative methods for bunch-length** as well as lateral size determination using visible light*** at the first of our new diagnostic dipole beamlines. Preliminary results as well as our concepts for achieving high sensitivity, good signal-to-noise ratio and time resolution will be presented and discussed at the conference.
* G.Schiwietz et al., J.Phys.:Conf. Series 1067, 072005 (2018)
** T.Mitsuhashi, M.Tadano, Proc. of EPAC’02, Paris, France, p. 1936
*** J.Breunlin et al., NIM- A803, pp.55 (2015) &refs. therein
 
slides icon Slides MOCO04 [10.924 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOCO04  
About • paper received ※ 04 September 2019       paper accepted ※ 08 September 2019       issue date ※ 10 November 2019  
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TUPP027 Development of a Precision Pepper-Pot Emittance Meter 364
 
  • G. Hahn
    PAL, Pohang, Republic of Korea
  • J.G. Hwang
    HZB, Berlin, Germany
 
  A fast single-shot emittance measurement device, a pepper-pot emittance meter, was developed. In the manufacturing stage, in order to guarantee the quality of the holes in the pepper-pot mask, we fabricated two mask using different methods that are made of phosphor bronze by optical lithography process and SUS by laser cutting. After the comparison of each SEM (Scanning Electron Microscope) measurement data, the phosphor bronze mask fabricated by lithography was found to be suitable. The rotation and translation matrices are applied on all images obtained by the camera to mitigate the relative angular misalignment errors between MCP, mirror and CMOS camera with respect to the mask. By applying the instrument in the NFRI ion source, the four-dimensional phase-space distribution of ion beams is retrieved and compared with the result measured by using a slit-scan method. In this paper, we describe the fabrication process, data analysis method and beam measurement results of the developed emittance meter.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-TUPP027  
About • paper received ※ 09 September 2019       paper accepted ※ 10 September 2019       issue date ※ 10 November 2019  
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WEPP003 A new button-type beam position monitor for BESSY II and BESSY VSR 500
 
  • J.G. Hwang, V. Dürr, F. Falkenstern, M. Ries, A. Schälicke, G. Schiwietz, D. Wolk
    HZB, Berlin, Germany
 
  Funding: This work was supported by the German Bundesministerium für Bildung und Forschung, Land Berlin and grants of Helmholtz Association.
The future BESSY VSR system involves more than one order-of-magnitude differences in the total charge of adjacent short and long bunches within the bunch train. Thus, any signal ringing beyond a nanosecond in time will cause a misreading of beam position and current, specifically for low bunch charges. This calls for improved performance for the bunch-selective operation of the beam-position-monitor (BPM) system. We report on the corresponding design and fabrication of a new button BPM with advanced features, such as impedance matching inside the button as well as optimization of insulator material, button size, and position, for reduced crosstalk between buttons.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-WEPP003  
About • paper received ※ 04 September 2019       paper accepted ※ 10 September 2019       issue date ※ 10 November 2019  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)