LINAC2014 - List of Authors (Nie, Y.C.)

Paper	Title	Page
TUPP022	RF Tuning of a S-band Hybrid Buncher for Injector Upgrade of LINAC II at DESY	478
	Y.C. Nie, M. Hüning, C. Liebig, M. Schmitz DESY, Hamburg, Germany
	LINACII at DESY currently provides 450 MeV electrons for the synchrotron radiation source PETRAIII. The injector upgrade of it aims to improve its reliability and mitigate the radiological activation due to electron losses at hundreds of MeV. Therefore, a 2.998 GHz hybrid buncher has been developed and will be installed in between a pre-buncher and LINAC II. It comprises a 1-cell standing-wave (SW) section for rapid acceleration and a 13-cells travelling-wave (TW) section for further bunching and acceleration. This paper focuses on its rf tuning procedure. The tuning strategy combines a non-resonant bead-pull measurement of complex electric field and a linear model for local reflection coefficient calculation. The tuning result is satisfying. Field unflatness of the TW section has been improved from ±9% to ±4%, and field in the SW section has been enhanced significantly. By using ASTRA simulation, it has been verified that the residual detuning of the structure is acceptable in view of beam dynamics performance.

Paper

Title

Page

RF Tuning of a S-band Hybrid Buncher for Injector Upgrade of LINAC II at DESY

478

Y.C. Nie, M. Hüning, C. Liebig, M. Schmitz
DESY, Hamburg, Germany

LINACII at DESY currently provides 450 MeV electrons for the synchrotron radiation source PETRAIII. The injector upgrade of it aims to improve its reliability and mitigate the radiological activation due to electron losses at hundreds of MeV. Therefore, a 2.998 GHz hybrid buncher has been developed and will be installed in between a pre-buncher and LINAC II. It comprises a 1-cell standing-wave (SW) section for rapid acceleration and a 13-cells travelling-wave (TW) section for further bunching and acceleration. This paper focuses on its rf tuning procedure. The tuning strategy combines a non-resonant bead-pull measurement of complex electric field and a linear model for local reflection coefficient calculation. The tuning result is satisfying. Field unflatness of the TW section has been improved from ±9% to ±4%, and field in the SW section has been enhanced significantly. By using ASTRA simulation, it has been verified that the residual detuning of the structure is acceptable in view of beam dynamics performance.