Update on the High Energy Booster Design Edith Nissen JLEIC R&D Meeting 8/22/2019

High Energy Booster Design Constraints Go from 8 GeV to 12.101 GeV K.E. Fit in the tunnel designed for the collider rings (I used the electron ring, but kept it to a single plane. Restrictions on part count, leads to arcs with roughly 2/3 of the cells in the electron ring.

Arc Design These were designed with roughly 2/3the cells of the electron collider ring, the bends at either end had to be reduced to match the geometry, making the dispersion not corrected. They use at 108 degree phase advance per cell.

Spin rotator sections Geometry was matched to electron ring, with a FODO cell that was of similar size to the arc cells, without interfering with too many bends. The quads in this section were used to correct the dispersion coming out of the arcs. Uses 3.6 meter dipoles to match geometry

Straight Sections The straight sections are made up of 6 FODO cells each, andcan be used to tune the machine.

Straight with Bypass A bypass was requested to avoid the detector region in the collider rings, The request was for a 5 meter excursion with a 50 meter distance. Thiswas achieved with 6 straight FODO cells, and 8 4 meter dipoles, for a 5.03m excursion with a distance at that point of ~46 meters. Does lead to large dispersion right next to the detector.

Total machine Due to the different bending in the arcs and the addition of the bypass, the pathlength is 2341.96 meters. Using a brute force approach to dispersion suppression does increase the prevalence of nonlinear dispersions in the straights

Total Machine (Continued) Length orbit5 alfa Gammatr 2341.960968 0.004517507046 18.87820645 q1 dq1 betxmax dxmax 27.70674027 8.22627052e-05 90.56304838 7.383733392 dxrms xcomax xcorms Q2 1.401638147 26.58754629 dq2 betymax dymax Dyrms -5.07387495e-05 111.6746613

Whole Machine

Conclusions The ring has a design,including an experimental bypass. The chromaticity correction system needs to be optimized. Some further geometric matching can be done to bring the arcs more in line with the collider rings Increasing the number of allowed elements should allevite some of these problems