|TUPP017||Thermal Performance of Diamond SR Extraction Mirrors for SuperKEKB||327|
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|
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