experimental facilities

1 BROOKHAVEN SCIENCE ASSOCIATES

Experimental Facilities

John HillDirector, NSLS-II Experimental Facilities Division

NSLS-II User WorkshopJuly 17, 2007


Novel features of DesignThe DBA-30 design has a number of novel features that offer a unique range of opportunities for our large, diverse community of users:

Low emittance Ultra-high flux and brightness soft x-ray and High current, hard x-ray undulator sourceslong straights

Damping wigglers Very intense broad band sources of hard x-rays

Soft Bends Bright sources of soft x-rays Large gaps to provide excellent far-IR source.

3 Pole Wigglers High-flux, bright sources of hard x-rays


Radiation Sources: Brightness


Radiation Sources: Flux


Three-pole WigglersAdded to provide hard x-ray dipoles without big impact

on the emittance.

Each BM port can either be a soft bend or a 3PW source~15 3PWs would increase the emittance ~ 10%

2 mrad source


Radiation Sources: Infra-Red

Standard gap BMs provide excellent mid and near IR sources Large gap (90 mm) BMs provide excellent far-IR sources


Electron Beam Size

Type of source Low- straight section (6.6m)

Hi- straight section (8.6m)

0.4T Bend magnet 1T three-pole wiggler

σx [μm] 28 99. 44.2 (35.4 - 122) 136

σx' [μrad] 19 5.5 63.1 (28.9-101) 14.0

σy [μm] 2.6 5.5 15.7 15.7

σy' [μrad] 3.2 1.8 0.63 0.62

Truly tiny electron beams…


Source Size vs. Photon Energy


Source Divergence vs. Photon Energy


Heat Load Calculations

Maximum thermal slope error in beam footprint = ±4 µrad

(cf Darwin width of 31 rad)

-8-6-4-202468

-20 -15 -10 -5 0 5 10 15 20

Crystal surface dimension in y-direction (mm)

Slop

e er

ror (

mic

ro ra

dian

s)

Undulator

Calculations for worst case U14 superconducting undulator: 2σ beam, Total power = 92 W (filtered)

Wiggler

-25-20-15-10

-505

10152025

-20 -15 -10 -5 0 5 10 15 20

Crystal surface dimension in y-direction (mm)

Slop

e er

ror (

mic

ro ra

dian

s)

Maximum thermal slope error in beam footprint = ± 23 µrad

Calculations for L=7m damping wiggler: 0.25 mrad, Total power = 1.8 kW (unfiltered)

Power from the insertion devices is large, but it can be handled


Experimental Floor• 1 pentant (= 6 sectors) served by 1 LOB:

72 offices6 labs (480 sf)

• Vibration studies (FEA) carried out to minimize sources and propagation of vibrations from ground up.• Long beamlines would have hutches outside the experimental hall.

BROOKHAVEN SCIENCE ASSOCIATES


Vibration Suppression at NSLS-II

Extensive FEA modeling of vibrations in facility underway (N. Simos)Goal is to:

• Understand site• Mitigate external and internal sources• Isolate sensitive beamlines

Possible solutions: slab thickening, isolation joints, trenches…

Studies indicate that cultural noise will be trapped by the floor

Service Bldg


NSLS-II Beamlines• 15 low- straights for user undulators

• Could potentially drive up to 30 beamlines by canting two undulators

• 4 high- straights for user undulators• Could potentially drive up to 8 beamlines by canting two undulators

• 8 high- straights for user damping wigglers• Could potentially drive up to 16 beamlines by canting two DWs

• 27 BM ports for UV and soft X-rays• Up to 15 of these can have 3-pole wigglers to provide hard x-rays.

• 4 large gap BM ports for far-IRAt least 58 beamlines

More w/ multiple IDs per straightMultiple hutches per beamline are also possible


Project BeamlinesProject goal: To provide a minimum suite of insertion device

beamlines to meet physical science needs that both exploit the unique capabilities of the NSLS-II source and provide work horse instruments for large user capacity.

• The beamlines are:• Inelastic x-ray scattering (0.1 meV)• Nanoprobe (1 nm)• Soft x-ray coherent scattering and imaging• Hard x-ray coherent scattering and SAXS• Powder diffraction (damping wiggler source)• EXAFS (damping wiggler source)


Nanoprobe

10 nm

1 nm

Mission• Nanoscience: hard-matter • Imaging, diffraction

Capabilities1nm, short working distance10nm, larger working distancePossible remote hutch

SourceU19 in lo- straight*

*A candidate for extended straight.


Inelastic X-ray Scattering

Mission•Low energy modes in soft matter•Phonons in small samples (Hi-P, single crystal..)

Capabilities0.1 meV, fixed energy1.0 meV, fixed energy

SourceU19 in lo- straight*

*A candidate for extended straight.

0.1 meV

1.0 meV


Hard X-ray Coherent Scattering

Mission• Slow dynamics in soft matter• Nanoscale imaging of hard matter• time-resolved SAXS (biological processes)

CapabilitiesXPCS/SAXSCoherent Diffraction

SourceU19 in hi- straight*

*gap > 7mm

Secondary optics

Coherent Diffraction/SAXS

XPCS


Soft X-ray Coherent ScatteringMission• Imaging of bio samples• Hard matter, magnetic systems

CapabilitiesCoherent imaging + microspectroscopyCoherent scatteringFast switching of polarization

Source2 x EPU 45 in lo- straight (canted at 0.25 mrad)


Powder DiffractionMission• Materials Science• time-resolved catalysis

Capabilities5-50 keVAnalyser-mode and strip-detector modeSample environments (high-P, low-T, high-T..)

Source3m damping wiggler in hi- straight

BM hutch

Powder-I

Powder-II


XAFS

MissionEnvironmental science, catalysisMaterials science

CapabilitiesMicroprobeIn-situ catalysis, controlled atmosphere

Source3m damping wiggler in hi- straight

BM hutch

EXAFS-I

EXAFS-II


Path Towards 1 nmKinoforms

=82 nm

Refractive optic with minimal absorptionE-beam at Lucent

Etching at BNL (CFN)

• Achieved 82 nm

• Theoretical calculations show 1nm is possible

• Technical challenge in fabricating multiple lenses with sufficiently smooth walls.

Multi-layer Laue Lenses

-150 -100 -50 0 50 100 150

0.0

0.2

0.4

0.6

0.8

1.0

Sample A Sample B Sample C Gaussian fit

Inte

nsity

(nor

mal

ized

)

X (nm)

=19 nm

Thin film multilayers, sectioned for use as ZPs

• Pioneered at ANL

• Achieved 19 nm

• Theoretical calculations show that 1nm is possible.

• Technical challenge in fabricating thick MLs with atomically smooth layers.


Path Towards 0.1 meVAsymmetric Optics acting as Dispersive Elements

Y. Shvyd’ko et al PRL (2006)

• Energy resolution controlled with asymmetry parameter• Achieve high energy resolutions at moderate photon

energies (9 keV)

Technical Challenges:•Fabrication and mounting of large Si crystals•Temperature stability

E=9.1 keV

E=2 meV


Summary

• Conceptual design of accelerator has matured into an exciting design, promising superlative experimental capabilities.

• World-leading performance extends from the far-IR to the very hard x-ray. A range of sources will be available to match the various scientific needs.

• These include unprecedented energy and spatial resolution for hard x-ray beamlines and world-leading resolution and flux for soft x-ray beamlines.

• Project insertion device beamlines have been identified. User community to define the scientific mission of these beamlines.

• Looking forward to your input and feedback during the workshop.

experimental facilities

Documents