EIC Second IR Design Vasiliy Morozov EIC Accelerator

EIC Second IR Design Vasiliy Morozov EIC Accelerator Collaboration Workshop October 7 -9, 2020

2 nd IR • 2 nd IR of the EIC －Off project －Consider alternative design choices －Possibility of the 2 nd IR is one of the EIC design requirements －Complementary measurements and capabilities to 1 st IR －Interest and support of the nuclear physics community • High-level requirements －High luminosity at a low CM energy of ~60 Ge. V －Detector acceptance satisfying physics requirements (what matters most for the machine design is the forward acceptance requirements) －Compatibility with running in parallel with the baseline detector 2

Complementarity to 1 st IR 3

Crossing Angle Crossing angle - avoid parasitic collisions due to short bunch spacing - for machine elements, to improve detection - reduce detector background However, crossing angle causes - Low luminosity - Beam dynamics issues avoided by Crab Crossing As a consequence: Effective head-on collision restored beam dynamic issues resolved 4

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Geometric and Machine Constraints 6

Ion 2 nd IR Optics up to 120 Ge. V 7

Ion 2 nd IR Optics from 120 to 275 Ge. V 8

Electron 2 nd IR Optics 9

2 nd IR Design Status 10

2 nd IR Design Optimization • Grid search and optimization in the luminosity/ detector acceptance/ beam parameter phase space • Each iteration involves － Lattice design update － Luminosity estimate － Acceptance simulation • Would like to streamline the process as much as possible • IRs optimized individually 11

Simultaneous Operation of Two IRs 12

Beam-Beam Tune Shift and Luminosity Sharing 13

Engineering Feasibility • Engineering feasibility of the most challenging magnets － Largest-aperture forward ion quad － Forward spectrometer dipole 14

Ongoing and Future Work • Extension of the electron and ion beam lines • Geometric and optical matching of the IR • Integration of the machine and detector components • Design optimization in terms of luminosity/ acceptance/ beam parameters • Simulation of detector acceptance • Evaluation of engineering feasibility of key IR elements • Chromaticity compensation and non-linear dynamics studies 15

Backup 16

Beam-Beam Tune Shift 17

Total Beam-Beam Tune Shift 18

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Far-Forward Angular Acceptance 20

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