1 brookhaven science associates nsls-ii photon sources & beamline systems qun shen director,...

1 BROOKHAVEN SCIENCE ASSOCIATES

NSLS-II Photon Sources & Beamline Systems

Qun ShenDirector, Experimental Facilities Division (XFD)

NSLS-II Beamline Development Information Meeting April 14, 2010

Email: [email protected]


Outline

• NSLS-II Photon Sources• Baseline & planned photon sources• Spectral brightness & flux• Optimization of insertion devices

• Beamline Systems• Overview of beamline systems• Beamline optics and expected

performance characteristics

• Guideline to design and construction schedule

• Technical assistance by light sources staff


Design Parameters of NSLS-II Storage Ring

NSLS-II Design ParametersRing energy (GeV) 3Ring current (mA) 500

Ring circumference (m) 792Number of DBA cells 30

Number of 9.3 m straights 15Number of 6.6 m straights 15

h in 9.3 m straights (m) 20.1v in 9.3 m straights (m) 3.4h in 6.6 m straights (m) 1.8v in 6.6 m straights (m) 1.1

Vertical emittance (nm-rad) 0.008Horizontal emittance (nm-rad) 0.55

RMS energy spread (%) 0.1RMS pulse length (ps) 15-30

Time between bunches (ns) 2Revolution period (s) 2.64

Number of bunches 1056Average bunch current (mA) 0.47

Average bunch charge (nC) 1.25

Overview of one super period of NSLS-II storage ring


Typical Sector Layout at NSLS-II

Low- ID

3PW / BM

High- ID

3PW / BM


Electron Source Size h,v and Divergence ’h,v

Type of source

Low- Straight Section (6.6m)

High- Straight Section (9.3m)

0.4T Bend Magnet

1.14T 3-Pole Wiggler

σh (μm) 33.3 107 125 167σh' (μrad) 16.5 5.1 91 98σv (μm) 2.9 5.2 13.4 12.3

σv' (μrad) 2.7 1.5 0.80 0.82

Low- Straight Section (6.6m)

High- Straight Section (9.3m) 3-pole Wiggler

Bending Magnet


Six Beamlines in NSLS-II Construction Project

• Inelastic X-ray Scattering (IXS)

• Hard X-ray Nanoprobe (HXN)

• Coherent Hard X-ray Scattering (CHX)

• Coherent Soft X-ray Scattering & Polarization (CSX)

• Sub-micron Resolution X-ray Spectroscopy (SRX)

• X-ray Powder Diffraction (XPD)

XPD 28-ID

HXN 3-ID

CHX 5-ID

IXS 10-ID

SRX 21-ID

CSX 23-ID

Note: beamline location assignments preliminary

Conceptual design report posted at http://www.bnl.gov/nsls2/docs/PDF/ CDRs_SixProjectBeamlines_NSLS-II.pdf


Currently Planned Insertion Devices at NSLS-II

Type of Device Purpose Quantity

Damping Wiggler (DW90): 90 mm period, 1.85 T, 2× 3.5 m Broadband 3

In-Vacuum Undulators (IVU): IVU20: 20-mm period, 1.05 T (> 5 mm gap), 3 m IVU21: 21-mm period, 0.91 T (> 5.5 mm gap), 1.5 m, canted IVU22: 22-mm period, 0.76 T (> 7 mm gap), 2× 3 m (tentative)

Hard X-ray211

Elliptically-polarizing undulator (EPU49): 49-mm period, 0.94 T (> 11.5 mm gap), 2× 2 m long, optionally canted by ~0.16 mrad

Soft X-ray 1

Three-Pole Wiggler: 1.14 T peak field, 20-cm long Broadband 1

• Undulators can be canted by 0-2 mrad in both low- and high- straight sections• DWs can also be canted but requires

modification of vacuum chamberCanting angle 0-2 mrad


Current and Potential Insertion Devices at NSLS-II

U20 U22 U17* U14* EPU49 DW90 SCW60 BM 3PWType IVU IVU CPMU SCU EPU PMW SCW Bend PMW

Photon energy range [keV] 1.9–20 1.8-20 2.1-25 1.8-40 0.18–7 <0.01–100

<0.01–200

<0.01 –12

<0.01 –25

Type of straight section Low-β High-β Low-β Low-β Low-β High-β Low-βPeriod length, U [mm] 20 22 17 14 49 90 60Total device length [m] 3.0 6.0 ~3 ~2 4.0 7.0 1.0 0.25

Number of periods 148 270 ~174 ~140 2 x 39 75 17 0.5Minimum magnetic gap [mm] 5 7 5 5 11.5 12.5 15 28Peak field linear mode B [T] 1.03 0.74 ~1.1 ~1.7 0.94 1.85 3.5 0.40 1.14

Max Ky in linear mode 1.83 1.52 ~1.7 ~2.2 4.34 15.7 19.6

Peak field circular mode B [T] 0.57Max K=2 Ky in circular mode 3.69

Min. h fundamental [keV] 1.6 1.8 ~2.1 ~1.8 0.17Critical energy [keV] 11.1 21 2.39 6.8

Maximum total power [kW] 7.9 9.1 ~9.2 ~16 8.8 67 34 0.32Horizontal angular power

density [kW/mrad]16 6.6 0.023 0.067

On-axis power density [kW/mr2] 66 90 ~80 ~105 32.8 62 25 0.088 0.26

* Requires additional R&D, with CPMU17 as near-term and SCU14 as far-term options


Spectral Brightness of NSLS-II Sources at 500mA


Spectral Flux of NSLS-II Sources at 500mA


Spectral Flux of NSLS-II Sources (cont’d)


Wiggler Comparisons


Spectral Flux of NSLS-II Infra-Red Sources

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


Optimization of Undulator Performance Given Accelerator Constraints

IVU Parameters IVU Parameters Reference Geometry:Reference Geometry: Pole Width: 40 mm Pole Height: 25 mm Pole Thickness: 3 mm (for λu = 20 mm)

Magnet Width: 50 mm

Magnet Height: 29 mm

Materials:Materials: Pole: Va Permendur NEOMAX Magnet: NdFeB

Radia Model (central part)Radia Model (central part)

βy0 = 3.4 m

βy0 = 1.06 m

Fundamental Photon Energy vs GapFundamental Photon Energy vs Gapfor Different IVU Periods (E = 3 GeV)for Different IVU Periods (E = 3 GeV)

λu= 20 mm

λu= 21 mm

λu= 22 mm

λu= 23 mm

IVU Lengths Satisfying Vertical IVU Lengths Satisfying Vertical “Stay Clear” Constraints “Stay Clear” Constraints in Low- in Low- and High-Beta Straight Sectionsand High-Beta Straight Sections

O. Chubar (NSLS-II)


Spectral Flux of Different IVUs – IXS “Candidates” – Satisfying e-Beam Vertical “Stay Clear” Constraint

E-Beam Energy: 3 GeVCurrent: 0.5 A NSLS-IIHigh-Beta (Long) Straight Section

Maximal Spectral Flux through 100 μrad (H) x 50 μrad (V) Aperture

~9.13 keV

~9.13 keV

O. Chubar (NSLS-II)

• Such insertion device optimization is done during conceptual design

• Not necessary for beamline development proposal


Three-pole Wigglers

• Added to provide hard x-ray dipole radiation with no significant impact on the emittance

• Up to 30 can be added to the lattice upstream of each dipole B

+2.125 mrad

0 mrad

+4.25 mrad

+2.5 mrad

1.5 mrad

BM-A BM-B3PW


3PW and BM Power Density Distributions

Magnetic Field

|θX| = 4.25 mrad |θX| ≈ 2.6 mrad θX= 0

Power Density Distribution from different parts of TPW and BM at 30 m (single-electron emission, integral over all photon energies, horizontal cuts at y = 0)

1.65 mrad

O. Chubar (NSLS-II)


3PW and BM Intensity Distributions (Hard X-rays)

Horizontal Cuts Horizontal Cuts at y = 0at y = 0

Vertical Cuts at x = 0

• Intensity distributions at different photon energies at 30 m from 3PW show effects from soft poles in 3PW and from adjacent BMs• Effect of such non-ideal

intensity distribution on microfocusing is being studied by a working group, and updates will be provided

O. Chubar (NSLS-II)


Beamline Systems Overview

Front-end (inside storage ring tunnel)

Enclosures and beam transport

Photon optical system

Utilities and safety system (PSS, EPS)

Endstation and experiment controls


Optical Systems

HXN Beamline Optical Layout (top view)

• Beamline optical systems are key functional elements of any synchrotron beamline. Functions may include: • Monochromators (single-crystal optics, gratings, multilayers) • Beam conditioning (mirrors, focusing optics)• Beam filtering (spectral filter, harmonic rejection mirror, spatial filter or beam-defining slits)• Power handling (high heat-load optics)• Imaging optics (zone-plate objective)

Yong Chu (NSLS-II)


Power Outputs from Insertion Devices

]A[]m[]T[]GeV[633.0]kW[ 20

20 ILBEP G

)(]A[]GeV[]T[84.10]W/mr[ 40

2

0

KGNIEBd

dPuG

•APS U33 2.4m produces similar power per unit solid-angle as NSLS-II IVU22 6m

O. Chubar (NSLS-II)


Cryogenic vs. Water Cooling of Si Optics

NSLS-II U20 @ min. gap: 1.8mm(h) x 0.9mm(v)

Bragg angle = 14o

Absorbed Power ~113W Peak Temp: 116.5 KSlope Error: 0.4 rad (due to thermal bump)

• Cryogenically cooled Si is needed (and is expected to work) for NSLS-II undulator sources• Water cooling is adequate for NSLS-II 3PW/BM sources V. Ravindranath (NSLS-II)


• Kirkpatrick-Baez (K-B) mirrors• Large acceptance aperture, achromatic focusing for

easy energy scanning• Focal size limited by critical angle: achieved ~25 nm

• Compound Refractive Lens• Refraction effect is weak so requires many lenses• Shape errors affect focal size: achieved ~50 nm

• Conventional Fresnel zone plate (FZP)• Easy to use, good efficiency for soft x-rays but poor efficiency for hard x-rays• Focal size limited by smallest features that can be fabricated: achieved ~15 nm

• Multilayer Laue-Lens (MLL)• High aspect ratio (>1000) Fresnel zones can be fabricated; good for hard x-rays• Difficult to tune energy• Theory shows <1 nm possible: achieved ~16 nm (1D)

• Multilayer mirrors• Good energy tunability; requires ultralow surface finish and precision ML deposition• Focal size limited by ML mirror slope errors: achieved ~8 nm (1D)

Variety of Cutting-Edge Focusing X-ray Optics

Above – XRF imaging of a test pattern, scanned through 2D focusing by crossed MLL, with resolution ~20nm x 40nm

Yan, Conley, Lima et al. (NSLS-II)Maser, Macrander, Shu et al. (ANL)


Canted Beamline Example: SRX Beamline

KB branch

ZP branch

• Two x-ray branches using two ~1.5m long U21-type undulators canted by 2 mrad• Two hor. mirrors to deflect ZP beam out to allow ~0.5 m separation in ZP hutch

Thieme et al. (NSLS-II)


Coherent Soft X-ray Beamline

• Two soft x-ray branches using 2x EPUs canted by 0.16 mrad• Branching mirror M1-A to

deflect beam outward for the coherent branch

Full polarization control branch

Coherent branch

Sanchez-Hanke, Reininger, et al. (NSLS-II)


NSLS-II Project Beamline Schedule


Assisting Users in Beamline Proposal Process

•BNL Light Sources scientific staff are part of the scientific user community, and their expertise can be very useful in the beamline development proposal process. NSLS-II and NSLS staff are encouraged to help out user groups who may need certain guidance and technical assistance

•This help may be in following forms• Providing advice and guidance in specific area of expertise; • Providing specific technical information such as source properties and existing

optical concepts of existing project beamlines; and• Helping to address certain technical issues on conceptual level if appropriate.

•Due to limited resources, NSLS-II and NSLS would not be able to provide engineering assistance on technical problems during BL proposal process


Beamline Development Sources & Optics Group

•Beamline Development Sources & Optics Group has been established to assist user groups on specific technical information and on addressing specific technical issues that may have broad interest in the community

•Users are encouraged to contact the members in specific areas of expertise

•Members of the Group: Steve Hulbert ([email protected]) – LeaderOleg Chubar ([email protected]) – source propertiesRuben Reininger ([email protected]) – gratings and mirrorsLonny Berman ([email protected]) – crystal optics and heat loadZhong Zhong ([email protected]) – high energy x-ray monochromatorsAndy Broadbent ([email protected]) – utilities and safety systems

•Group meets weekly to discuss any issues that requires attention; XFD Director participates in these meetings to provide oversight and to communicate any additional information as needed


Beamline Development - Beamline Contact Group

•Beamline Contact Group consists of existing beamline group leaders and others with specific expertise in particular type of beamlines; User groups are encouraged to contact the appropriate staff for questions and answers generally related to the type of beamlines of interest.

•Beamline Contacts: Cecilia Sanchez-Hanke / Ruben Reininger – soft x-ray and VUV beamlinesLonny Berman – 3-pole wiggler and bend-magnet x-ray beamlinesEric Dooryhee – Damping wiggler x-ray beamlinesAndrei Fluerasu / Juergen Thieme – undulator x-ray beamlines

•Beamline contact may seek additional help from the Sources and Optics group to discuss any technical issues, by communicating the topic to any member in the Sources and Optics group.


Thank You!

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1 brookhaven science associates nsls-ii photon sources & beamline systems qun shen director,...

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