16
1 BROOKHAVEN SCIENCE ASSOCIATES 1 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II Lattice Design 1. TBA-24 Lattice Design - Advantages and shortcomings Low emittance -> high chromaticity -> small DA from nonlinear dynam. TBA dispersion region major limitation for reducing sextupole strength 2. DBA-32 Lattice Design - Damping Wigglers for Emittance Control Linear design with working point for non-linear DA optimization ID’s eXtra long (15m) and standard Length (6m) Dipole designed for damping wigglers DA and frequency map for bare lattice with 11 sextupole families S. Kramer, J. Bengtsson, S. Krinsky, T. Shaftan, D. Wang, L. Yun, I. Pinayev May 11,2006

NSLS-II Lattice Design

  • Upload
    quasim

  • View
    33

  • Download
    3

Embed Size (px)

DESCRIPTION

NSLS-II Lattice Design. S. Kramer, J. Bengtsson, S. Krinsky, T. Shaftan, D. Wang, L. Yun, I. Pinayev May 11,2006. TBA-24 Lattice Design - Advantages and shortcomings Low emittance -> high chromaticity -> small DA from nonlinear dynam. - PowerPoint PPT Presentation

Citation preview

Page 1: NSLS-II Lattice Design

1 BROOKHAVEN SCIENCE ASSOCIATES1 BROOKHAVEN SCIENCE ASSOCIATES

NSLS-II Lattice Design

1. TBA-24 Lattice Design - Advantages and shortcomings

Low emittance -> high chromaticity -> small DA from nonlinear dynam.

TBA dispersion region major limitation for reducing sextupole strength

2. DBA-32 Lattice Design - Damping Wigglers for Emittance Control

Linear design with working point for non-linear DA optimization

ID’s eXtra long (15m) and standard Length (6m)

Dipole designed for damping wigglers

DA and frequency map for bare lattice with 11 sextupole families

DA with alignment tolerances

3. Summary of Lattice Parameters for DBA-32(8)

S. Kramer, J. Bengtsson, S. Krinsky, T. Shaftan, D. Wang, L. Yun, I. Pinayev

May 11,2006

Page 2: NSLS-II Lattice Design

2 BROOKHAVEN SCIENCE ASSOCIATES2 BROOKHAVEN SCIENCE ASSOCIATES

TBA-24 Lattice Design

TBA-24 Lattice Design worked on for ~2 years

Reached 1.5 nm emittance in 630m but DA small, 2.2nm 758m

Page 3: NSLS-II Lattice Design

3 BROOKHAVEN SCIENCE ASSOCIATES3 BROOKHAVEN SCIENCE ASSOCIATES

TBA-24 Lattice Features

TBA-24 Lattice very flexible

Lower emittance per period than DBA, 24 period εx >0.38 nm

Tune variable over big range for constant emittance

α1 variable without breaking symmetry of lattice, i.e. isochronous tune

TBA-24 Lattice has small dispersion like DBA-48

Even with low chromaticity (~2.2/period) sextupoles strong

DA low and challenging to expand without giving up on low emittance

Minimum number of ID’s for users

Page 4: NSLS-II Lattice Design

4 BROOKHAVEN SCIENCE ASSOCIATES4 BROOKHAVEN SCIENCE ASSOCIATES

Reconsider DBA Lattice Option

Higher emittance/period more periods, more ID’s

Use extra ID’s for emittance control with damping wigglers

Wigglers have potentially less DA impact and counter users changes

Optimize emittance damping with low field dipoles

Dispersion region has freedom to increase dispersion, reducing chromatic sextupole strength

Lesson from TBA-24 study of ID Quadruplet for phase and beta functions matching for undulators

Page 5: NSLS-II Lattice Design

5 BROOKHAVEN SCIENCE ASSOCIATES5 BROOKHAVEN SCIENCE ASSOCIATES

Basic DBA-32 Cell 6m ID

Qx= 1.09 (1.13), ξx = -3.38 (-3.6) εx =1.66 (1.74)nm (ESRF@3GeV)

Qy= 0.72 (0.35), ξy = -1.25 (-1.01) C= 868 (845)m +35.2m in dipoles

Page 6: NSLS-II Lattice Design

6 BROOKHAVEN SCIENCE ASSOCIATES6 BROOKHAVEN SCIENCE ASSOCIATES

Two Types of ID with SP=8

ID’s = 15m +3* 6m C=929.8m εx =1.66 nm ξx,y = -3.26,-1.13/per

Page 7: NSLS-II Lattice Design

7 BROOKHAVEN SCIENCE ASSOCIATES7 BROOKHAVEN SCIENCE ASSOCIATES

Emittance vs Damping Wiggler B-field

Energy Spread vs Wiggler Field

Lw = 54m

ρw = 1.4*Bρ/Bw

Bdipole=0.33T

Bdipole=0.66TBdipole=0.66T

Bdipole=0.33T

Emittance change vs Wiggler Field

Page 8: NSLS-II Lattice Design

8 BROOKHAVEN SCIENCE ASSOCIATES8 BROOKHAVEN SCIENCE ASSOCIATES

Damping Wigglers in 4-15m ID

Power radiated could exceed 125KW in one 15 ID, canting will reduce threat to front end components and yield 3 or more user beams

Page 9: NSLS-II Lattice Design

9 BROOKHAVEN SCIENCE ASSOCIATES9 BROOKHAVEN SCIENCE ASSOCIATES

DBA32 Working Point SP=8

Tune selected from DA scan and optimized for reduced Closed Orbit Amplification

Page 10: NSLS-II Lattice Design

10 BROOKHAVEN SCIENCE ASSOCIATES10 BROOKHAVEN SCIENCE ASSOCIATES

Closed Orbit Amplification Factors

Quadrupole alignment tolerance reduced by small Beta functions and tune

Page 11: NSLS-II Lattice Design

11 BROOKHAVEN SCIENCE ASSOCIATES11 BROOKHAVEN SCIENCE ASSOCIATES

DBA32 Tune Scan for Cell

At each tune value: driving terms were optimized to 3rd order and DA area calculated yields peak near (4.29,2.615)

Page 12: NSLS-II Lattice Design

12 BROOKHAVEN SCIENCE ASSOCIATES12 BROOKHAVEN SCIENCE ASSOCIATES

DA for Tune and 11 Sext. Families

Frequency map shows diffusion at high order resonances and tune shifts

Page 13: NSLS-II Lattice Design

13 BROOKHAVEN SCIENCE ASSOCIATES13 BROOKHAVEN SCIENCE ASSOCIATES

Alignment tolerances on Quads and Sextupoles <100μm corrected

DA and momentum aperture for constant momentum error adequate for injection

Asymmetry in momentum aperture from high order chromaticity and dispersion

Tolerances on BPM to sextupole centering okay for < 30μm

7 BPM and 7 Corrector magnets / period

Page 14: NSLS-II Lattice Design

14 BROOKHAVEN SCIENCE ASSOCIATES14 BROOKHAVEN SCIENCE ASSOCIATES

Adding Synchrotron Oscillations Adding Synchrotron Oscillations

DA maintains reasonable values but momentum aperture more symmetric

For random alignment tolerances < 100 μm with correction injection okay

Page 15: NSLS-II Lattice Design

15 BROOKHAVEN SCIENCE ASSOCIATES15 BROOKHAVEN SCIENCE ASSOCIATES

NSLS-II Lattice ParametersNSLS-II Lattice Parameters

Energy 3 3.6 GeV

Io (Total Current) 0.500 0.241 Amps

Circumference 929.805 929.805 meters

fo (revolution freq) 0.3224 0.3224 MHz

Harmonic No. 1560 2*3*4*5*13

α1 , α2 , α1/ α2 3.32*10-4 -1.82*10-4 -1.81

Uo (Dipole) 234.5 486.2 KeV

Uo (Dip.+1.8T) 1231.2 1921.8 KeV

εcrit1.96 3.287 KeV

εx (bare) 1.66 2.39 nm

εx (54m 1.8T) 0.47 0.687 nm

δe bare (+1.8T) 0.046 (0.10) 0.0558 (0.12) %

Lb (bare, 3%RF) 2.7 (9) 3.11 (10.34) mm (psec)

x,y,e (bare) 79.5,79.4, 39.7 46, 45.9, 23 msec

(Qx, Qx) =

(34.38, 20.68) (ξx, ξx) = (-104.4, -36.2)

βx, βy (6m ID) = 6.2, 1.42 βx, βy (15m ID) = 15.1, 16.2

Page 16: NSLS-II Lattice Design

16 BROOKHAVEN SCIENCE ASSOCIATES16 BROOKHAVEN SCIENCE ASSOCIATES

NSLS-II Lattice SummaryNSLS-II Lattice Summary

DBA-32 lattice has advantage of dispersion region optimized to reduce sextupole strengths and nonlinear driving terms

Extra ID’s used for damping wigglers to lower emittance and control user changes of the emittance from changing gaps

Damping wigglers provide high flux, brilliance beams for users missing from dipoles, dipole beam great VUV sources

Dynamic aperture with tolerances, first look appears achievable

Quadruplet in ID’s essential for control of linear optics from undulators