80 likes | 166 Views
Investigating the impact of snake orbital angle on spin tune shift at 250 GeV in particle accelerators. Analysis of spin tune shifts due to snake rotations, energy dependence, and polarization transmission variations. Conclusions on spin tune proximity to 1/2 with snake angle changes.
E N D
Spin Tune as function of snake orbital angleMarch 31, 2009 Mei, Vadim, Thomas
Orbit angle in snakes 300 murad angle -> 0.046 spin tune shift at 250 GeV APEX: ramp 1 operation APEX: ramp 2
Snake angle in present operation At 9 o’clock the zero orbit angle at snake location leads to few mm excursion at a neighboring location. In both rings.
Spin tune shifts Due to rotators at snakes. Strong energy dependence. Spin tune shift due to snakes: energy dependence (Waldo’s calculations)
At injection With no change of snake angle With -0.3mrad change of snake angle With -0.3mrad change of snake angle With no and -0.3mrad change of snake angle With 0.3mrad change of snake angle With no change of snake angle
Conclusions • Indication of Blue spin tune at injection is further away from 1/2 with no change of snake orbital angle • -0.3mrad snake angle at injection in Blue seems to push the spin tune either close or further away from 1/2 • +-0.3mrad snake orbital angle change along the ramp: • Yellow shows difference in polarization transmission • Difference in Blue is not so clear . Spin tune close to ½ (?).