Upload
blanche-kelly
View
222
Download
0
Embed Size (px)
Citation preview
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 KrinskyNSLS-II Accelerator Physics Group Leader
NSLS-II Magnet Production Workshop April 11-12, 2012
3 BROOKHAVEN SCIENCE ASSOCIATES
Beam Property GoalHorizontal emittance (nm-rad) <1Vertical emittance (nm-rad) 0.010Average current (mA) 500Straights for insertion devices 27Orbit stability (% of beam size) 10Touschek lifetime (hrs) >3Top-off injection frequency (/min) <1
Some Basic NSLS-II Project Goals
4 BROOKHAVEN SCIENCE ASSOCIATES
Technical Requirements & SpecificationsEnergy 3.0 GeVCircumference 792 mNumber of Periods 30 DBALength Long Straights 6.6 & 9.3mEmittance (h,v) <1nm, 0.008nmMomentum Compaction .00037Dipole Bend Radius 25mEnergy Loss per Turn <2MeV
Energy Spread 0.094%RF Frequency 500 MHzHarmonic Number 1320RF Bucket Height >2.5%RMS Bunch Length 15ps-30psAverage Current 500maCurrent per Bunch 0.5maCharge per Bunch 1.2nCTouschek Lifetime >3hrsTop-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
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
FF
C CC
C
C
C F
3-pole wiggler
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) 108 175 44.2 29.6x’ (µrad) 4.6 14 63.1 16.9
y (µm) 4.8 12.4 15.7 3.1y’ (µrad) 1.7 0.62 0.63 2.6
Lattice
Functions
Electron Beam Sizes
& Divergences
Most challenging
Beam stability
Requirements
= ~ 0.31 μm
SR Lattice & Electron Beam Sizes/Divergences
11 BROOKHAVEN SCIENCE ASSOCIATES
6543
21231
SR BPMs and Correctors
Fast correctors (Qty=3)Fast response – 2 kHzWeak strength – 15 μradUtilized for –•Fast orbit feedback
Slow correctors (Qty=6)Slow response – 2 HzStrong strength – 800 μradUtilized for –•Alignment•Slow orbit feedback
BPMs
156 mm slow 100 mm slow 30 mm fast (air core)
SC SC
SCSC
SCSC
FC FC 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
δacc
Small η
δacc
Large η
Lifetime
(hrs)
3% 2.5% 5.5
2.5% 2.5% 3.3
2.5% 2.0% 2.9
2.5% 1.5% 2.3
Touschek Lifetime
σs=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
1
2
34
5
NSLS-II Beamlines UnderwayBeamline ConstructionProjects SE TE
NSLS-II Project Beamlines•Inelastic X-ray Scattering (IXS) 1 1•Hard X-ray Nanoprobe (HXN) 1 1•Coherent Hard X-ray Scattering (CHX) 1 1•Coherent Soft X-ray Scat & Pol (CSX) 2 2•Sub-micron Res X-ray Spec (SRX) 1 1•X-ray Powder Diffraction (XPD) 1 1NEXT MIE Beamlines•Photoemission-Microscopy Facility (ESM) 2 3•Full-field X-ray Imaging (FXI) 1 1•In-Situ & Resonant X-Ray Studies (ISR) 1 2•Inner Shell Spectroscopy (ISS) 1 1•Soft Inelastic X-ray Scattering (SIX) 1 1•Soft Matter Interfaces (SMI) 1 2ABBIX Beamlines•Frontier Macromolecular Cryst (FMX) 1 1•Flexible Access Macromolecular Cryst (AMX) 1 1•X-ray Scattering for Biology (LIX) 1 1Type II Beamlines•Spectroscopy Soft and Tender (NIST) 2 6•Beamline for Materials Measurements (NIST) 1 1•Microdiffraction Beamline (NYSBC) 1 1
TOTAL 2128
18 Beamline Construction Projects Underway21 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-IINSLS-II,, NEXTNEXT, and , and ABBIXABBIX Insertion DevicesInsertion Devices
PPM: Pure Permanent MagnetEM: Electro MagnetH: Hybrid Magnetic Design
BL ID
straight type
ID type, incl. period (mm)
Length Kmax FE type† FE aperture (h x v, mrad)
# of ID's (base scope)
# FE's Project Procurement
CSX lo-β EPU49 (PPM) x2 4m (2 x 2m) 4.34 canted (0.18) 0.6 x 0.6 2 1 NSLS-II DoneIXS hi-β IVU22 (H) x2 6m (2 x 3m) 1.52 std 0.5 x 0.3 1 1 NSLS-II RFP due Jan.’12HXN lo-β IVU20 (H) 3m 1.83 std 0.5 x 0.3 1 1 NSLS-II DoneCHX lo-β IVU20 (H) 3m 1.83 std 0.5 x 0.3 1 1 NSLS-II DoneSRX lo-β IVU21 (H) 1.5m 1.79 canted (2.0) 0.5 x 0.3 1 1 NSLS-II DoneXPD hi-β DW100 (H) 6.8m (2 x 3.4m) ~16.5 DW 1.1 x 0.15 0 1 NSLS-II Done
ESM hi-β EPU56 (PPM) & EPU180 (EM)
3m4m
3.646.8 canted (0.5) 0.6 x 0.6 2 1 NEXT
SIX hi-β EPU49 (PPM) x2 6m (2 x 3.2m) 3.5 std 0.6 x 0.6 1 1 NEXT
ISR hi-β IVU23 (H) 3.0m 1.6-2.07* canted** (2.0) 0.5 x 0.3 1 1 NEXT Procure w/LIX
SMI lo-β IVU22 (H) 1.3m 2.05 canted** (2.0) 0.5 x 0.3 1 1 NEXT
ISS hi-β DW100 (H) 6.8m (2 x 3.4m) ~16.5 DW 1.1 x 0.15 0 1 NEXT Done
FXI hi-β DW100 (H) 6.8m (2 x 3.4m) ~16.5 DW 1.1 x 0.15 0 1 NEXT Done
FMX lo-β IVU21 (H) 1.5m 1.79 canted (2.0) 0.5 x 0.3 1 1 ABBIX SRX Option
AMX lo-β IVU21 (H) 1.5m 1.79 canted (2.0) 0.5 x 0.3 1 0 (joint w/FMX) ABBIX SRX Option
LIX hi-β IVU23 (H) 3.0m 1.6-2.07* canted** (2.0) 0.5 x 0.3 1 1 ABBIX Procure w/ISR
† For canted IDs/FEs, ( ) shows canting angle in mrad * Depending on location within ID straight section** Off-center canting magnet location in IDstraight section
17 BROOKHAVEN SCIENCE ASSOCIATES
ID Field Error Comparison
SLS Alba ESRF SOLEIL NSLS-II(DW) NSLS-II (Und)
By First Integral [G.cm] 20(<1cm) 30 40 2050 (|y|=0) 100(|y|=3mm) 50
Bx First Integral [G.cm] 7 4030 (|y|=0) 60(|y|=3mm) 30
By Second Integral [G.cm.cm] 10000 6000 10000 10000 10000 10000Bx Second Integral [G.cm.cm] 600 10000 5000 5000Normal quadrupole [G] 50 50 50 70 50 50Skew quarupole [G] 50 5 50 70 50 50Normal sextupole [G/cm] 60 20 60 30 50 50Skew sextupole [G/cm] 60 20 60 50 50Normal octupole [G/cm/cm] 100 10 150 20 50 50Skew octupole [G/cm/cm] 100 10 50 50
B
IdssB
B
L1
0
)(1
LB
ILdssB
Bdsx
sL
02
0
0
221
0
1
)(1
•1st & 2nd
Integrals
Cf. 1000 G.cm.cm corresponds to 1 micron in displacement at NSLS-II