1. 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)

2. 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

3. 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

4. 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

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

6. 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,
DA = 16sx × 41sy at Q = 59.22, 59.16

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

8. 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

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

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

11. 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 = and 8.7 (1/m3), L = 0.25 m
25σx
57σy