Status of IR / Nonlinear Dynamics Studies Detector design (Rik) Detector background simulations (Latifa) Proposal to Generic Detector R&D program received positive review and was recommended for funding Forward tagging for heavy ions (LDRD) Generating cross-section tables for Sartre (Vasiliy) Generating collision data using updated BeAGLE (Vasiliy) Ion collider ring Compensation elements for detector region (Mark Wiseman, Vasiliy) Electron collider ring Optimization of chromatic compensation (Yuri) Testing hybrid multi-bend achromat (Fanglei)

Next Steps for Ion Collider Ring Complete detector solenoid compensation Complete simulation with multipoles, misalignments and detector solenoid Consider orbit excursion at injection Consider space for skew quads and correctors for detector solenoid compensation Implement the smaller baseline 𝛽 ∗ Consider locations of multipole corrector spools Simulate local compensation of systematic multipoles Estimate random multipoles Simulate acceleration cycle with field-dependent multipoles

Corrector Elements in Detector Region Started discussion with a group of engineers led by Mark Wiseman Provided specifications for corrector elements Dipole kickers for closed orbit correction, design important for detector acceptance Skew quads near FFGs, would like to integrate into corrector spools Correction system design and detector region optimization were done in parallel Integrated the correction system into the latest detector region design

Y. Nosochkov (SLAC), F. Lin (JLab) August 8, 2017 Update on dynamic aperture for electron ring based on short FODO arc cells Y. Nosochkov (SLAC), F. Lin (JLab) August 8, 2017

Outline Updated lattice – re-matched to remove a minor mismatch (from Fanglei) Updated chromaticity correction including SBCC phase optimization Preliminary dynamic aperture

Dynamic aperture without errors LEGO tracking using 1024 turns, no errors, E = 5 GeV, e = 5.7 nm-rad DA = 23sx × 41sy at Q = 59.53, 59.567 DA = 16sx × 41sy at Q = 59.22, 59.16

Dynamic aperture vs Dp/p Tune = 59.53, 59.567  DA without errors is at least 10s at Dp/p = 0.4%

Non-linear field errors in simulations PEP-2 non-linear field errors for dynamic aperture tracking, except magnets with high beta function (final focus quads and some SBCC magnets), where systematic and random (rms) errors are reduced to 10-4 / 5×10-5 in quads, and 10-3 / 2×10-4 in SBCC sextupoles Systematic DBn/Bref at Rref RMS DBn/Bref at Rref

Dynamic aperture with PEP-2 non-linear field errors Tune = 59.53, 59.567; five seeds of random errors  Low impact on DA  May try increasing errors in high-beta magnets

DA from Elegant Simulation Tunes: .22 / .16 Tunes: .53 / .567 RF off RF on or off ?

Comparison Using matrices for matching: 4 sextupole families in two SBCCs K2L = 2.2, -4.5, -2.6, 3.9 (1/m2) Optimized phase advance from sextupoles to IP 1x=3.7531, 2y=4.2535, 3x=5.2434, 4y=6.2413 Conventional 2-family arc sextupoles (opposite polarities in two arcs) 50 cells with x/y sextupoles per arc K2 = 14.7 and 6.0 (1/m3), L = 0.25 m 38σx 70σy Using real quads for matching 4 sextupole families in two SBCCs K2L = 3.8, -4.5, -1.5, 3.8 (1/m2) Optimized phase advance from sextupoles to IP 1x=3.761, 2y=4.767, 3x=5.261, 4y=6.767 Conventional 2-family arc sextupoles (opposite polarities in two arcs) 40 cells with x/y sextupoles per arc K2 = -23.3 and 8.7 (1/m3), L = 0.25 m 25σx 57σy