1 BROOKHAVEN SCIENCE ASSOCIATES Abstract NSLS-II Performance and Magnet Lattice S. Krinsky, NSLS-II Project In this presentation, we introduce the NSLS-II storage ring magnet lattice and review the basic machine performance parameters. In particular, we discuss the requirements on dynamic aperture necessary to achieve acceptable injection efficiency and Touschek lifetime. The tight specifications on the harmonic content of the magnetic fields in the NSLS-II multipole magnets have been set to assure sufficient dynamic aperture not only for the bare NSLS-II lattice but also to leave room in the nonlinearity budget for the installation of 27 or more insertion devices to serve as the sources for the user research programs. *Work performed under auspices of the United States Department of Energy, under contract DE-AC02- 98CH10886

2 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II Performance and Magnet Lattice Samuel Krinsky NSLS-II Accelerator Physics Group Leader NSLS-II Magnet Production Workshop April 11-12, 2012

3 BROOKHAVEN SCIENCE ASSOCIATES Beam PropertyGoal Horizontal emittance (nm-rad)<1 Vertical emittance (nm-rad)0.010 Average current (mA)500 Straights for insertion devices27 Orbit stability (% of beam size)10 Touschek lifetime (hrs)>3 Top-off injection frequency (/min)<1 Some Basic NSLS-II Project Goals

4 BROOKHAVEN SCIENCE ASSOCIATES Technical Requirements & Specifications Energy 3.0 GeV Circumference 792 m Number of Periods 30 DBA Length Long Straights 6.6 & 9.3m Emittance (h,v) <1nm, 0.008nm Momentum Compaction Dipole Bend Radius 25m Energy Loss per Turn <2MeV Energy Spread 0.094% RF Frequency 500 MHz Harmonic Number 1320 RF Bucket Height >2.5% RMS Bunch Length 15ps-30ps Average Current 500ma Current per Bunch 0.5ma Charge per Bunch 1.2nC Touschek Lifetime >3hrs Top-Off Injection rate 1/min

5 BROOKHAVEN SCIENCE ASSOCIATES Injection System Local Control Room Linac Tunnel Klystron Gallery Equipment Racks for Linac and LTB line

6 BROOKHAVEN SCIENCE ASSOCIATES Storage Ring

7 BROOKHAVEN SCIENCE ASSOCIATES Storage Ring Cell Configuration 10 quadrupole magnets per cell, independent power supplies (initially 4 quads in the matching section) 9 sextupole families, 3 chromatic and 6 geometric. (initially 12 sextupole families) 2 slow correctors and 2 BPMs per girder to allow girder by girder orbit correction 2 additional high stability BPMs in each straight section to improve stability 3 fast correctors per cell for fast orbit correction most of the magnet to magnet separation is standardized to 17.5 cm. (straights increased from 5/8 to 6.6/9.3) 3-pole wiggler was added to the lattice to provide dipole radiation F F F C C C C C C F 3-pole wiggler

8 BROOKHAVEN SCIENCE ASSOCIATES Lattice Functions for One Cell

9 BROOKHAVEN SCIENCE ASSOCIATES Reduction of Emittance with Damping Wigglers Baseline design has three damping wigglers: L=7m, B=1.8T

10 BROOKHAVEN SCIENCE ASSOCIATES Types of source Long ID 1-T 3-Pole wiggler Bend magnet Short ID  x (µm)  x’ (µrad)  y (µm)  y’ (µrad) Lattice Functions Electron Beam Sizes & Divergences Most challenging Beam stability Requirements = ~ 0.31 μm SR Lattice & Electron Beam Sizes/Divergences

11 BROOKHAVEN SCIENCE ASSOCIATES SR BPMs and Correctors Fast correctors (Qty=3) Fast response – 2 kHz Weak strength – 15 μrad Utilized for – Fast orbit feedback Slow correctors (Qty=6) Slow response – 2 Hz Strong strength – 800 μrad Utilized for – Alignment Slow orbit feedback BPMs 156 mm slow 100 mm slow 30 mm fast (air core) SC FC

12 BROOKHAVEN SCIENCE ASSOCIATES Touschek Scattering Energy acceptance is smaller if electron is scattered at high dispersion Scattering rate is smaller for high dispersion, since bunch volume bigger δ acc Small η δ acc Large η Lifetime (hrs) 3%2.5% % %2.0% %1.5%2.3 Touschek Lifetime σ s =15ps w/o Landau Cavity

13 BROOKHAVEN SCIENCE ASSOCIATES Requirements on Dynamic Aperture Injection: we need to maintain particles with initial displacement of about 11mm. We therefore look for solutions with calculated on-momentum dynamic aperture of >15mm (including IDs and errors) Touschek lifetime: we require the Touschek lifetime to be >3hrs with Landau cavity. Therefore, our goal is to achieve a calculated energy acceptance of +/-2.5% for scattering at low dispersion and +/- 2.0 % for scattering at high dispersion. This will provide sufficient margin to allow for effects not included in the tracking simulations.

14 BROOKHAVEN SCIENCE ASSOCIATES Introduction of Third Chromatic Sextupole Knob Allows reduction of second order horizontal chromaticity while maintaining flexibility in Geometric sextupoles to correct the tune-shift with amplitude. --moved one of the defocusing chromatic sextupoles toward max dispersion

15 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II Beamlines Underway Beamline ConstructionProjects SETE NSLS-II Project Beamlines Inelastic X-ray Scattering (IXS)11 Hard X-ray Nanoprobe (HXN)11 Coherent Hard X-ray Scattering (CHX)11 Coherent Soft X-ray Scat & Pol (CSX) 22 Sub-micron Res X-ray Spec (SRX)11 X-ray Powder Diffraction (XPD)11 NEXT MIE Beamlines Photoemission-Microscopy Facility (ESM)23 Full-field X-ray Imaging (FXI)11 In-Situ & Resonant X-Ray Studies (ISR)12 Inner Shell Spectroscopy (ISS)11 Soft Inelastic X-ray Scattering (SIX)11 Soft Matter Interfaces (SMI)12 ABBIX Beamlines Frontier Macromolecular Cryst (FMX)11 Flexible Access Macromolecular Cryst (AMX)11 X-ray Scattering for Biology (LIX)11 Type II Beamlines Spectroscopy Soft and Tender (NIST)26 Beamline for Materials Measurements (NIST)11 Microdiffraction Beamline (NYSBC)11 TOTAL Beamline Construction Projects Underway 21 Simultaneous Endstations (SE) 28 Total Endstations (TE) 22 additional beamlines (25 SE) have been proposed by the user community and approved by the SAC and NSLS-II but are not yet funded Beamlines with design and construction underway

16 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II, NEXT, and ABBIX Insertion Devices PPM: Pure Permanent Magnet EM: Electro Magnet H: Hybrid Magnetic Design BL ID straight type ID type, incl. period (mm) LengthK max FE type † FE aperture (h x v, mrad) # of ID's (base scope) # FE'sProjectProcurement CSX lo-βEPU49 (PPM) x24m (2 x 2m)4.34canted (0.18)0.6 x 0.621NSLS-IIDone IXS hi-βIVU22 (H) x26m (2 x 3m)1.52std0.5 x 0.311NSLS-IIRFP due Jan.’12 HXN lo-βIVU20 (H)3m1.83std0.5 x 0.311NSLS-IIDone CHX lo-βIVU20 (H)3m1.83std0.5 x 0.311NSLS-IIDone SRX lo-βIVU21 (H)1.5m1.79canted (2.0)0.5 x 0.311NSLS-IIDone XPD hi-βDW100 (H)6.8m (2 x 3.4m)~16.5DW1.1 x NSLS-IIDone ESM hi-β EPU56 (PPM) & EPU180 (EM) 3m 4m canted (0.5)0.6 x 0.621NEXT SIX hi-βEPU49 (PPM) x26m (2 x 3.2m)3.5std0.6 x 0.611NEXT ISR hi-βIVU23 (H)3.0m *canted** (2.0)0.5 x 0.311NEXTProcure w/LIX SMI lo-βIVU22 (H)1.3m2.05canted** (2.0)0.5 x 0.311NEXT ISS hi-βDW100 (H)6.8m (2 x 3.4m)~16.5DW1.1 x NEXTDone FXI hi-βDW100 (H)6.8m (2 x 3.4m)~16.5DW1.1 x NEXTDone FMX lo-βIVU21 (H)1.5m1.79canted (2.0)0.5 x 0.311ABBIXSRX Option AMX lo-βIVU21 (H)1.5m1.79canted (2.0)0.5 x (joint w/FMX) ABBIXSRX Option LIX hi-βIVU23 (H)3.0m *canted** (2.0)0.5 x 0.311ABBIXProcure w/ISR † For canted IDs/FEs, ( ) shows canting angle in mrad * Depending on location within ID straight section ** Off-center canting magnet location in ID straight section

17 BROOKHAVEN SCIENCE ASSOCIATES ID Field Error Comparison 1 st & 2 nd Integrals Cf G.cm.cm corresponds to 1 micron in displacement at NSLS-II

18 BROOKHAVEN SCIENCE ASSOCIATES Commissioning Schedule