Final focus designs for crab waist colliders

The crab waist collision scheme promises significant luminosity gain. The successful upgrade of the $\mathrm{DA}\mathrm{\Phi }\mathrm{NE}$ collider proved the principle of crab waist collision and increased luminosity 3 times. Therefore, several new projects try to implement the scheme. The paper reviews interaction region designs with the crab waist collision scheme for already existent collider $\mathrm{DA}\mathrm{\Phi }\mathrm{NE}$ and SuperKEKB, presently undergoing commissioning, for the projects of SuperB in Italy, CTau in Novosibirsk and FCC-ee at CERN.

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Figure 1

Layout of the crossing angle collision.

Figure 2

Crab waist collision scheme.

Figure 3

Optical functions of $\mathrm{DA}\mathrm{\Phi }\mathrm{NE}$ interaction region with crab waist sextupoles.

Figure 4

Optical functions of SuperKEKB LER interaction region with crab waist sextupoles.

Figure 5

Optical functions of SuperKEKB interaction region: (a) LER, (b) HER.

Figure 6

Dynamic aperture for LER SuperKEKB with different crab sextupole strength.

Figure 7

Optical functions of SuperB HER interaction region with crab waist sextupoles.

Figure 8

On momentum dynamic aperture of SuperB LER and HER: black line—crab sextupoles are off, red and blue—crab sextupoles strength of 50% and 100% of nominal respectfully.

Figure 9

Optical functions of the CTau interaction region.

Figure 10

Optical functions of FCC-ee interaction region variant 1.

Figure 11

Dynamic aperture for FCC-ee interaction region variant 1.

Figure 12

Optical functions of FCC-ee interaction region variant 2.

Figure 13

Dynamic aperture for the FCC-ee interaction region variant 2 (50 turns, without damping, crab sextupole is off, rf is on).

Figure 14

Dynamic aperture degradation for FCC-ee interaction region variant 2, black is with crab sextupole OFF, red with crab sextupole ON, includes only nonlinearities of the interaction region, on momentum particles.

Figure 15

Layout of the simple interaction region.

Figure 16

Optical functions of FCC-ee interaction region variant 3.

Figure 17

Dynamic aperture degradation for FCC-ee interaction region variant 3, black is with crab sextupole OFF, red with crab sextupole ON, includes only nonlinearities of the interaction region, on momentum particles.