1. BB Effect and Early Separation Scheme Guido Sterbini CERN – MCS - MA 7 December 2006

2. D0 D1 TRIPLETS D0 [m] D0 4 m Early separation scheme

3. Distance between the beams [  ] Distance from the IP [m] How does the early separation scheme impact on the BB effect?

4. s y 50  rad 80  rad d1 d2 Trade-off between the geometrical loss factor, the BB effect and the intrusion in the detectors regions

5. x y We launched the particles in the different directions in the x-y plane.

11. Nominal D0a (  rad)D0b (  rad) 80 40120 20140 The beam dynamic’s behavior of D0 seems not to depend on the different distribution of kick’s angle between D0a and D0b.

12. The 45º direction seems critical. Why? The Early Separation Scheme is very sensitive to this problem: we need to deepen the BB results It would be very interesting to test different index of chaos with respect to an experimental results in order to have a hint on the maximum number of reduced LRBB interaction we can afford.

13. Appendix We can consider the first two ATLAS slots: We can consider the first two ATLAS slots: Slot1 starting at 3.49 m from IP with a total length of 1.09 m Slot1 starting at 3.49 m from IP with a total length of 1.09 m Slot2 starting at 6.80 m from IP with a total length of 1.86 m Slot2 starting at 6.80 m from IP with a total length of 1.86 m We can obtain the 8 Tm splitting the dipole into two: We can obtain the 8 Tm splitting the dipole into two: a 4 T D0a in Slot1 (it should be transparent a.s.m.p.) a 4 T D0a in Slot1 (it should be transparent a.s.m.p.) a 4 T D0b in Slot2 (it should be bulky a.s.m.p.) a 4 T D0b in Slot2 (it should be bulky a.s.m.p.)