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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 

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NSLS-II Performance and Magnet Lattice

Samuel KrinskyNSLS-II Accelerator Physics Group Leader

NSLS-II Magnet Production Workshop April 11-12, 2012

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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

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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

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Injection System

Local Control Room

Linac

Tunnel

Klystron Gallery

Equipment Racks for Linac and LTB line

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Storage Ring

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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

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Lattice Functions for One Cell

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Reduction of Emittance with Damping Wigglers

Baseline design has three damping wigglers: L=7m, B=1.8T

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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

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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

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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

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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.

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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

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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

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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

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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

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Commissioning Schedule