Keyword: feedback
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MOP048 The Design of Low Noise Magnet Power Supply power-supply, FPGA, multipole, controls 136
 
  • K.-H. Park, S.-H. Jeong, Y.-G. Jung, D.E. Kim, H.-G. Lee, S.B. Lee, B.G. Oh, H.S. Suh
    PAL, Pohang, Kyungbuk, Republic of Korea
  • W.S. Choi, I.S. Ko
    POSTECH, Pohang, Kyungbuk, Republic of Korea
  
  The accelerator needs a high stable magnet power supply(MPS) with low noise output. The stability requirements of the some MPSs in accelerator were in the range of the ~10 ppm. There are many noise sources which affect the stability of MPS. Thus the design of the MPS requests much attention on the noise reduction scheme from the beginning stage. The noise on the MPS divided into some sources such as the ripple voltage coming from rectifier for the DC link, switching noise at the FET or IGBT on the high voltage, noise coming digital logics around DSP and its peripheral circuits, ground matters on the analogue signal process and so on. This paper analyzed the noise sources and described the way how to build the low noise power supply.  
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TUP005 A Mirror-Less, Multi-Beam Photonic Free-Electron Laser Oscillator Pumped Far Beyond Threshold electron, laser, radiation, free-electron-laser 334
 
  • P.J.M. van der Slot, K.-J. Boller, A. Strooisma
    Mesa+, Enschede, The Netherlands
  
  Funding: This research is supported by the Dutch Technology Foundation STW, which is part of the Netherlands Organisation for Scientific Research, and which is partly funded by the Ministry of Economic Affairs
In a photonic free-electron laser electrons are transmitted through a photonic crystal in the form of one or multiple electron beams to generate coherent Cerenkov radiation. Here we consider a photonic-crystal slab consisting of a two-dimensional, periodic array of bars inside a rectangular waveguide, with both ends tapered to provide complete transmission of an electromagnetic wave. By appropriately designing the photonic-crystal slab, we obtain a backward wave interaction at low electron beam energy of around 15 kV, that results in distributed feedback of the radiation on the electrons without any external mirrors being present. Here we numerically study the dynamics of the laser oscillator when pumped far beyond threshold with one or multiple electron beams. We show that using multiple beams with the same total current provide better suppression of higher-order modes and can produce more output power, compared to the laser pumped by a single beam of the same total current. 		 
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WEP037 Development Activites Related to RF Cables for Good Phase Stability electron, klystron, network, controls 654
 
  • J. Hu, H.-S. Kang, H.-S. Lee
    PAL, Pohang, Kyungbuk, Republic of Korea
  
  XFEL systems reqiure extreme RF stabilities in amplitude and phase. RF cables as parts of the systems also require very high stabilites. RF cable measurement is performed to choose good cables. Simple measurement method and test results are presented. To enhance the phase stability of RF cables a prototype jacket surrounding a RF cable is constructed and the test result is described. Finally, a modification for phase measurement of RF cables is presented.  
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