Touschek lifetime and gap height

Fig. 3 displays the Touschek lifetime, again normalized to $\kappa$ = 0.1%, as a function of the mini gap full height. The ideal lattice assuming 100% halo coupling would have reduced lifetime for full gap heights $\leq$ 10 mm. Assuming 0.1% for both core and halo coupling the mini gaps show no effect. After introducing misalignment errors (fixed-$\delta$-calculation) we see that the halo coupling is larger than the core coupling but not at 100%.

Including synchrotron oscillation seriously decreases lifetime for any gap height. However after coupling correction, the $\kappa$-normalized lifetime recovers and becomes almost independent of mini gap height.

Fig. 4 illustrates how lifetime limitations from the mini gap insertion are removed by coupling correction.

  

Figure 3: Touschek lifetime vs. insertion gap full height:

  

Figure: Touschek lifetime vs. emittance coupling factor $\kappa$ without (left) and with (right) coupling correction for different seeds of alignment error settings. Points not lying on the dotted T  $\propto \sqrt {\kappa }$ curve for the ideal lattice indicate beam losses at the insertion's 4 mm gap. Actually the average lifetime is higher with reduced coupling!