Author: Fukuma, H.
Paper Title Page
TUPP017 Thermal Performance of Diamond SR Extraction Mirrors for SuperKEKB 327
 
  • J.W. Flanagan, M. Arinaga, H. Fukuma, H. Ikeda, G. Mitsuka, Y. Suetsugu
    KEK, Ibaraki, Japan
  • E. Mulyani
    BATAN, Yogyakarta, Indonesia
  • E. Mulyani
    Sokendai, Ibaraki, Japan
 
  The SuperKEKB accelerator is a high-current, low-emittance upgrade to the KEKB double ring collider. The beryllium extraction mirrors used for the synchrotron radiation (SR) monitors at KEKB suffered from heat distortion due to incident SR, leading to systematic changes in magnification with beam current, and necessitating continuous monitoring and compensation of such distortions in order to correctly measure the beam sizes.* To minimize such mirror distortions, quasi-monocrystalline CVD diamond mirrors have been designed and installed at SuperKEKB.** Diamond has a very high heat conductance and a low thermal expansion coefficient. With such mirrors it is hoped to reduce the beam current-dependent magnification to the level of a few percent at SuperKEKB. Preliminary measurements of mirror distortion during SuperKEKB commissioning show very promising results with regard to thermal performance, though full beam currents have not yet been stored in the SuperKEKB rings. Measurements of the thermal deformation of the diamond mirrors will be presented in this paper, along with a description of the design of the mirrors and their mounts, and issues encountered during commissioning.
*M. Arinaga et al., NIM, A499, p. 100 (2003).
**J.W. Flanagan et al., "Diamond mirrors for the SuperKEKB synchrotron radiation monitors," Proc. IBIC2012, Tsukuba, Japan p. 515 (2012).
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-TUPP017  
About • paper received ※ 09 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)  
 
TUPP018 Synchrotron Radiation Monitor for SuperKEKB Damping Ring in Phase-III Operation 331
 
  • H. Ikeda, J.W. Flanagan, H. Fukuma, H. Sugimoto, M. Tobiyama
    KEK, Ibaraki, Japan
 
  The SuperKEKB damping ring (DR) commissioned in March 2019, before main ring (MR) Phase-III operation. The design luminosity of SuperKEKB is 40 times that of KEKB with high current and low emittance. We constructed the DR in order to deliver a low-emittance positron beam. A synchrotron radiation monitor (SRM) was installed for beam diagnostics at the DR. Streak camera and gated camera were used for measurement of the damping time and the beam size. This paper shows the design of DR SRM and the result of the measurement.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-TUPP018  
About • paper received ※ 04 September 2019       paper accepted ※ 08 September 2019       issue date ※ 10 November 2019  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)