A Study of the One-Third Integer Resonance Extraction for the 200 GeV Accelerator

Results of a detailed numerical study on the slow extraction of 200-400 GeV beams from the NAL accelerator are presented. Topics discussed are: position and strength of sextupoles, effects of octupole components in the ring magnets, vertical motion with the resonance 2¿y + ¿x = 61, and effects of ripples in the quadrupole current. With two sextupoles of strength 400-800 kG/m, the turn separation is ~1 cm when the septum radial position is 3 cm. The direction of the beam at the septum can be varied with correction octupoles. A possible advantage of introducing a local bump in the closed orbit near the septum is also discussed.