Author: Nishiwaki, M.
Paper Title Page
WEPME014 Progress in Development of New LLRF Control System for SuperKEKB 2953
 
  • T. Kobayashi, K. Akai, K. Ebihara, A. Kabe, K. Nakanishi, M. Nishiwaki, J.-I. Odagiri
    KEK, Ibaraki, Japan
  • H. Deguchi, K. Harumatsu, K. Hayashi, T. Iwaki, J. Mizuno, J. Nishio, M. Ryoshi
    Mitsubishi Electric TOKKI Systems, Amagasaki, Hyogo, Japan
 
  For the SuperKEKB project, a new LLRF control system was developed to realize high accuracy and flexibility. It is an FPGA-based digital RF feedback control system using 16-bit ADC's, which works on the μTCA platform. The FPGA boards control accelerating cavity fields and cavity tuning, and the EPICS-IOC is embedded in each of them. The CSS-BOY was adopted for a user interface of our system. High power test of the new LLRF control system was performed with the ARES Cavity of KEKB. The obtained feedback control stability with a klystron drive was sufficient as well as the low-level evaluation result. And auto tuner control also worded successfully. The start-up sequencer program for the cavity operation and auto-aging program also worked very well. The temperature characteristics of the system depend largely on band-pass filters (BPF). We tried to tune the BPF to reduce the temperature coefficient. Consequently the temperature dependence was improved to satisfy the required stability.  
 
THPFI013 Development of Cylindrical-type 1.2 MW High Power Water-load for Super KEKB 3318
 
  • K. Watanabe, K. Ebihara, A. Kabe, K. Marutsuka, M. Nishiwaki
    KEK, Ibaraki, Japan
  • Y. Kawane, A. Miura
    Nihon Koshuha Co. Ltd, Yokohama, Japan
 
  We have developed and manufactured CW 1.2 MW high power water-load for the use of the Super KEKB, an electron – positron double-ring collider at KEK. The tank and rf window of the water-load is the circular and cylindrical-type. The material to absorb the rf power is a tap water. This load is equipped on the 3rd port of the circulators to safe the 1.2 MW CW klystrons to drive the ARES cavities in main ring. The operational frequency is 508.9 MHz. A proto-type model of this water-load was fabricated at Sep 2012, and tested using by high power klystron (1 MW) at Oct 2012 at KEK D2-ET station. The result of high power test will be reported in this paper.  
 
THPWA012 The Development of a New Type of Electron Microscope using Superconducting RF Acceleration 3654
 
  • N. Higashi
    The University of Tokyo, Graduate School of Science, Tokyo, Japan
  • A. Enomoto, Y. Funahashi, T. Furuya, Y. Kamiya, S. Michizono, M. Nishiwaki, H. Sakai, M. Sawabe, K. Ueno, M. Yamamoto
    KEK, Ibaraki, Japan
  • M. Kuriki
    HU/AdSM, Higashi-Hiroshima, Japan
  • S. Yamashita
    ICEPP, Tokyo, Japan
 
  We are developing a new type of electron microscope (EM), which adopts RF acceleration in order to exceed the energy limit of DC acceleration used in conventional EMs. It enables us to make a high-voltage EM more compact and to examine thicker specimens, and possibly to get better spatial resolution. Using a superconducting RF cavity, we can operate the EM in CW mode to obtain a beam flux comparable to that in DC mode. Low energy dispersion ΔE/E , e.g. 10-6 or better, is required for good spatial resolution in EMs, while it is usually between 10-3 to 10-4 in accelerators. We have thus designed a special type of cavity that can be excited with the fundamental and second-harmonic frequencies simultaneously; TM010 and TM020. With the two-mode cavity, the energy dispersion of the order of 10-5 would be obtained by modifying the peak of accelerating field to be flattened. As the proof-of-principle of our concept, we are developing the prototype using a 300 keV transmission electron microscope (TEM), to which a new photocathode gun and the two-mode cavity are attached. We have already manufactured the cavity and it is under test, and the gun is under construction.