1. SPEAR3 Chicane, Accelerator Physics Update, February 10, 2005 Electron optics design review August 11, 2004 –“… no show stoppers. However, …” Additional electron dynamics simulations –Add insertion devices to computer model –Add damping and smaller ID gaps Scraper measurements –Lifetime vs. ID gap study –Injection loss vs. ID gap study Magnetic tolerance specifications J. Corbett, M. Cornacchia, R. Hettel, Y. Nosochkov, G. Portmann, T. Rabedeau, A. Ringwall, J. Safranek, J. Sebek, A. Terebilo, M. Yoon

2. Chicane BL13 BL12 7.6 meters 2.2 m RF 4.8 m matching straight 3 m standard straight

3. East Pit Baseline optics Chicane optics matching straight,  y = 4.8 m matching straight,  y = 2.5 m long straight,  y = 10 m long straight,  y = 1.6 m

4. Electron dynamics 3D harmonic oscillator Nonlinear elements: sextupoles, wigglers Limit to dynamic stability: dynamic aperture. Need sufficient aperture for lifetime and injection

5. Dynamic aperture required for injection Stored beamInjected beam septum magnet iron

6. Dynamic aperture simulations (from previous review) Baseline opticsChicane optics Did not include wigglers Did not include damping Course grid of initial conditions LIMITATIONS:

7. New simulations including wigglers and damping Baseline optics Chicane optics

8. High-density tracking & Tune maps Chicane optics Baseline optics

9. BL12 gap; aperture scans BL9 aperture scans –Lifetime vs. vertical orbit –Lifetime ~ constant over 4 mm –Systematic errors –Re-measure with scrapers, 11/2004 BL12 gap, conservative –12 – 2 = 10 mm at BL9 –Scales to 6.2 mm at BL12 BL12 gap, aggressive –12 – 4 = 8 mm at BL9 –Scales to 5.0 mm at BL12 Orbit bump at BL9 12 mm aperture.

10. Five fit parameters: Measured lifetime vs. vertical aperture

11. More tracking with apertures

12. Measured injection vs. vertical aperture

13. BL12 field specifications On-axis (x=y=0) specifications, normal, b n, and skew, a n –Integrated quadrupole < 50 G –Integrated sextupole < 75 G/cm –Integrated octupole < 40 G/cm 2 Off-axis specifications –1 st integral of B y < 100 + 50*|x| G*cm, |x|<2.5 cm –1 st integral of B x < 40 + 75*|x| G*cm, |x|<2.5 cm –2 nd integral of B y < 1.5e4+1e4*|x| G*cm 2, |x|<2.5 cm. –2 nd integral of B x < 5e3+1e4*|x| G*cm 2, |x|<2.5 cm –1 st integral deriv. < 50+150*|x| G; |x|<2.5 cm, Peak field transverse roll-off –dB y /dx < 11000+5500*|x| G/cm, |x|<2.5 cm (BL12) –d 2 B y /dx 2 < 15000+20000*|x| G/cm 2, |x|<2.5 cm (BL12) Accelerator physics group will review fields, once the ID is designed. Accelerator physics group will review magnetic measurements plan.