1. Collimation Optimisation
Frank Jackson, ILC BDS meeting, SLAC Jan 10, 2006

2. Collimation Performance
BDS (20,15,2mrad) decks all rely on post-NLC ‘survivable spoiler’ optics
Collimation phase advances and lattice bandwidth not been optimised yet
Good simulated performance relies on tight energy spoiler settings, combined with more aggressive absorber apertures

3. NLC FD Bandwidth
Exact phases and well behaved beta functions at FD

4. ILC 20 mrad lattice Non-exact phase advances (esp in vertical)
x =2.76 y =2.34
Non-exact phase advances (esp in vertical)
Poorer bandwidth

5. ILC-FF9 Collimation Optimisation
x =2.75 y =2.75
Restore phase advances with matching section
Bandwidth worsens
Not only exact phase solution

6. Optimisation Strategy
Tricky balance of phase and bandwidth variation
Goal is to search the space of solutions for optimum
Complement with spoiler/absorber aperture variation, tracking simulations

7. ILC-FF9
x =2.99 y =2.99

8. ILC-FF9
x =2.51 y =2.51