LIBD: TI8 Stability22 November 2011 1

TI8 STABILITY STUDY

L. Drosdal, V. Kain

LIBD: TI8 Stability22 November 2011 2

TI8 stability studies

2 November 2011 (1.5h) – YASP trajectory data

• Peaks up to 450 mm from average trajectory observed

• Pattern is not symmetric!

LIBD: TI8 Stability22 November 2011 3

Magnet current variations

MAD-X simulations using observed variations in magnet currents at extraction/start of TI8

as field errors:

MSE correlation

Observed variations cause fluctuations up to ~400 mm

LIBD: TI8 Stability22 November 2011 4

MSE error trajectories

Comparing the MSE error simulations to the observed trajectory variations from YASP:

The observed variations are only partly explained!

Distribution of MSE variations is not even around average (1):

LIBD: TI8 Stability22 November 2011 5

Orbit error – x0

To explain the missing peak we investigate an orbit error at x0

Position of peaks fit well, but is not symmetric – offset in distribution

Source unknown, needs investigation!

LIBD: TI8 Stability22 November 2011 6

Trajectory checks

Using selected Yasp trajectories it is clear that there is a combined effect:

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Summary TI8 instability

The overall result can be explained by two factors:

1. MSE current variations

2. X0 error – Source unknown!

Further investigation using MIA

LIBD: TI8 Stability22 November 2011 8

TI2 flashback

Good fit of MADX simulation of MSE error to yasp data: