Gao, J.

Paper	Title	Page
TUC3MA01	ILC DR Alternative Lattice Design	94
	Y. Sun, Z. Y. Guo PKU/IHIP, Beijing J. Gao IHEP Beijing, Beijing
	The International Linear Collider (ILC) which is based on super-conducting RF acceleration technology requires the damping rings to provide beams with extremely small equilibrium emittances, and large acceptance to ensure good injection efficiency for high emittance, high energy spread beam from the positron source. In order to reduce the cost for ILC damping rings, an alternative lattice which is different from the baseline configuration design has been designed with modified FODO arc cells，and the total quadrupole number has been reduced by half. At the same time, to decrease the total cost involved in constructing access shafts needed to supply power, cryogenics etc. for the wigglers and other systems, the number of wiggler sections is decreased from 8 to 4, and further to 2. This new lattice has been optimised to have a good dynamic aperture. This alternative ILC damping ring lattice design will reduce the cost largely compared with the baseline design.
	Slides
TUPMA005	Simulation Study on Bunch Lengthening	106
	Y. Sun, Z. Y. Guo PKU/IHIP, Beijing J. Gao IHEP Beijing, Beijing
	The bunch lengthening phenomenon is resulted from one of the most severe single bunch instabilities in electron storage rings. As for BEPCII, controlling the bunch length is the most critical task to fulfil the designed luminosity goal. A new code is developed to calculate the single bunch length and energy spread in storage rings using FORTRAN. In this code, the wake field is calculated using an analytical formula. The bunch length and energy spread under different bunch current are calculated for BEPCII. The tracking results clearly show that the microwave instability threshold is around 65 mA for BEPCII storage ring. The tracking results of this code are in good accordance with those from other codes.
TUPMA006	Study on the BEPCII Lattice	109
	Y. Sun, Z. Y. Guo PKU/IHIP, Beijing J. Gao IHEP Beijing, Beijing
	BEPCII, the upgrading project of the Beijing Electron-Positron Collider (BEPC), has been designed with a luminosity of 1033 cm-2s-1 at the -charm energy region. According to the beam-beam simulation results, the luminosity of BEPCII with a crossing collision angle of 11 mrad is about 0.50×1033 cm-2s-1 with the original operation mode at the working point of 6.53/5.58. To increase the operating luminosity of the BEPCII, a low momentum compaction factor (?P) collision mode has been studied which can increase the luminosity to 0.54×1033 cm-2s-1. If the bunch length of the low ?P mode is reduced from 1.5 cm to 1.2 cm, a mode with vertical beta function at IP equal to 1.2 cm could push the luminosity to 0.828×1033 cm-2s-1 at the working points 6.53/5.56. Also, the BEPCII synchrotron radiation mode is optimized to get a larger dynamic aperture and much more stable tunes.