SLS-2/Cosami meeting Mar. 16, 2016 Andreas Streun Report from 5th DLSR workshop, Mar. 9-11, DESY Haisheng Xu Report from 2nd TWIICE workshop, Feb. 8-10, Oxford, and latest results on impedances and instabilities Ciro Calzolaio News from longitudinal gradient superbend design

Report from 5th workshop on diffraction limited storage rings DESY, March 9-11, 2016 2 ½ days mixed science & accelerator workshop New science possibilities (H. Reichert, P. Wilmott) small emittance  clean undulator spectrum  operation without monochromators bandwidth  1/(periods  harmonic)  0.5...0.05% imaging & diffraction experiments profit most from lower emittance, spectroscopy less coherent imaging: sample < probe low emittance  long working distances  bulky beam line components possible (fabrication)

Max IV (M. Eriksson, P. Tavares) Latest commissioning results 74% injection efficiency stable >120 mA w/o FB & HC  prediction: 40 mA unstable 10 hr lifetime with 80 mA after 20 Ah beam dose shunts available for gradient correction, not yet used Misalignments: 25 mm/0.2 mrad element to girder, 50 mm/0.2 mrad girders 100 MHz RF = FM radio, just buy: 5 €/Watt “flexibility vs. vagueness”: simplify design “storage rings are consumables” cost 3 GeV ring = 7% of project cost 1.5 GeV ring  1 beam line split functions to different rings, build 1 ring/decade... plans for MAX IV upgrade or new ring....

Project status SIRIUS (Lin Liu) under construction, start operation 2017 ESRF-EBS (P. Raimondi) procurement in progress APS-U (G. Decker, V. Sajaev) CDR available, funded (?) lattice very similar to ESRF; anti-bends under consideration  40 pm bunch replacement: strong injector / beam dump Spring8-2 (T. Ishikawa) include ring-XFEL, plans until 2040 PETRA-4 (C. Schroer) 20 pm round, ESRF lattice, CDR 4/2018 Diamond-2 (R. Bartolini) double TBA = ESRF cell w/o center bend replace user bends by undulators/wigglers Elettra-2 (E. Karantzoulis) 6BA lattice, CDR in preparation ALS-U (R. Falcone) coherent soft X-rays, 50 pm round beam swap out injection using 3rd ring for accumulation 6 mm width NEG coated chambers Soleil (A. Nadji) first considerations

MOGA Kicker magnets Magnet design ESRF-EBS 3 sextupole + 1 octupole family, 10 seeds DA SIRIUS 9 quadrupole + 14 sextupole families, DA + Touschek incl. 2 random misalignments and OCO constraints on tune, chroma, straight dispersion, lattice symmetry Diamond-2 + APS-U linear and nonlinear optimization Kicker magnets ALS-U swap out: 5.4 ns rise/fall APS-U swap out: 11.4 ns (15 kV), 5 ns possible SIRIUS non-linear kicker: 70 mT at 8 mm, 3.2 ms half sine 1.6 kA, 7.6 kV Magnet design SIRIUS 3.2 T (!) permanent magnet NdFeB superbend Elettra-2 3D-girder with lower and upper magnet support for “thin” magnets (i.e. length < radial size)

The “large booster club”: SLS, ALBA, SIRIUS, [CANDLE] Round beams PETRA-4 Moebius ring with 2 roations per turn same cell corrects vertical and horizontal chromaticity build clean –I transformer, non-interleaved SF and SD problem: DA for using existing injector Soleil Local round beam insertion under construction [?] 2 x 3 skew quads + s.c. solenoid apparent emittance hor. and vert. = sqrt(ex ey) APS-U full coupling ? The “large booster club”: SLS, ALBA, SIRIUS, [CANDLE] SIRIUS 50 bends, no straights, 3 pm emittance Comments on SLS-2 throw away girders, use concrete pedestals (M. Eriksson) head tail instability dipole mode (m=0) if both momentum compaction and chromaticity are negative (E. Karantzoulis) feedback can control that (R. Bartolini)