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1 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II Photon Sources & Beamline Systems Qun Shen Director, Experimental Facilities Division (XFD) NSLS-II Beamline Development.

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Presentation on theme: "1 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II Photon Sources & Beamline Systems Qun Shen Director, Experimental Facilities Division (XFD) NSLS-II Beamline Development."— Presentation transcript:

1 1 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II Photon Sources & Beamline Systems Qun Shen Director, Experimental Facilities Division (XFD) NSLS-II Beamline Development Information Meeting April 14,

2 2 BROOKHAVEN SCIENCE ASSOCIATES 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

3 3 BROOKHAVEN SCIENCE ASSOCIATES Design Parameters of NSLS-II Storage Ring NSLS-II Design Parameters Ring energy (GeV)3 Ring current (mA)500 Ring circumference (m)792 Number of DBA cells30 Number of 9.3 m straights15 Number of 6.6 m straights15  h in 9.3 m straights (m) 20.1  v in 9.3 m straights (m) 3.4  h in 6.6 m straights (m) 1.8  v in 6.6 m straights (m) 1.1 Vertical emittance (nm-rad)0.008 Horizontal emittance (nm-rad)0.55 RMS energy spread (%)0.1 RMS pulse length (ps)15-30 Time between bunches (ns)2 Revolution period (  s) 2.64 Number of bunches1056 Average bunch current (mA)0.47 Average bunch charge (nC)1.25 Overview of one super period of NSLS-II storage ring

4 4 BROOKHAVEN SCIENCE ASSOCIATES Typical Sector Layout at NSLS-II Low-  ID 3PW / BM High-  ID 3PW / BM

5 5 BROOKHAVEN SCIENCE ASSOCIATES 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 σ h (μm) σ h ' (μrad) σ v (μm) σ v ' (μrad) Low-  Straight Section (6.6m) High-  Straight Section (9.3m) 3-pole Wiggler Bending Magnet

6 6 BROOKHAVEN SCIENCE ASSOCIATES 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 CDRs_SixProjectBeamlines_NSLS- II.pdf

7 7 BROOKHAVEN SCIENCE ASSOCIATES Currently Planned Insertion Devices at NSLS-II Type of DevicePurposeQuantity Damping Wiggler (DW90): 90 mm period, 1.85 T, 2× 3.5 mBroadband3 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-ray 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-ray1 Three-Pole Wiggler: 1.14 T peak field, 20-cm longBroadband1 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 chamber Canting angle 0-2 mrad

8 8 BROOKHAVEN SCIENCE ASSOCIATES Current and Potential Insertion Devices at NSLS-II U20U22U17*U14*EPU49DW90SCW60BM3PW TypeIVU CPMUSCUEPUPMWSCWBendPMW Photon energy range [keV]1.9– –7 <0.01– 100 <0.01– 200 <0.01 – 12 <0.01 – 25 Type of straight sectionLow-βHigh-βLow-β High-βLow-β Period length, U [mm] Total device length [m]3.06.0~3~ Number of periods148270~174~1402 x Minimum magnetic gap [mm] Peak field linear mode B [T] ~1.1~ Max K y in linear mode ~1.7~ Peak field circular mode B [T]0.57 Max K=  2 K y in circular mode 3.69 Min. h fundamental [keV] ~2.1~ Critical energy [keV] Maximum total power [kW]7.99.1~9.2~ Horizontal angular power density [kW/mrad] On-axis power density [kW/mr 2 ]6690~80~ * Requires additional R&D, with CPMU17 as near-term and SCU14 as far-term options

9 9 BROOKHAVEN SCIENCE ASSOCIATES Spectral Brightness of NSLS-II Sources at 500mA

10 10 BROOKHAVEN SCIENCE ASSOCIATES Spectral Flux of NSLS-II Sources at 500mA

11 11 BROOKHAVEN SCIENCE ASSOCIATES Spectral Flux of NSLS-II Sources (cont’d)


13 13 BROOKHAVEN SCIENCE ASSOCIATES 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

14 14 BROOKHAVEN SCIENCE ASSOCIATES Optimization of Undulator Performance Given Accelerator Constraints IVU Parameters Reference Geometry: Pole Width: 40 mm Pole Height: 25 mm Pole Thickness: 3 mm (for λ u = 20 mm) Magnet Width: 50 mm Magnet Height: 29 mm Materials: Pole: Va Permendur NEOMAX Magnet: NdFeB Radia Model (central part) β y0 = 3.4 m β y0 = 1.06 m Fundamental Photon Energy vs Gap for Different IVU Periods (E = 3 GeV) λ u = 20 mm λ u = 21 mm λ u = 22 mm λ u = 23 mm IVU Lengths Satisfying Vertical “Stay Clear” Constraints in Low- and High-Beta Straight Sections O. Chubar (NSLS-II)

15 15 BROOKHAVEN SCIENCE ASSOCIATES Spectral Flux of Different IVUs – IXS “Candidates” – Satisfying e-Beam Vertical “Stay Clear” Constraint E-Beam Energy: 3 GeV Current: 0.5 A NSLS-II High-Beta (Long) Straight Section Maximal Spectral Flux through 100 μrad (H) x 50 μrad (V) Aperture ~9.13 keV O. Chubar (NSLS-II) Such insertion device optimization is done during conceptual design Not necessary for beamline development proposal

16 16 BROOKHAVEN SCIENCE ASSOCIATES 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 mrad 0 mrad mrad +2.5 mrad  1.5 mrad BM-A BM-B 3PW

17 17 BROOKHAVEN SCIENCE ASSOCIATES 3PW and BM Power Density Distributions Magnetic Field |θ X | = 4.25 mrad |θ X | ≈ 2.6 mrad θ X = 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)

18 18 BROOKHAVEN SCIENCE ASSOCIATES 3PW and BM Intensity Distributions (Hard X-rays) Horizontal Cuts at 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)

19 19 BROOKHAVEN SCIENCE ASSOCIATES 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

20 20 BROOKHAVEN SCIENCE ASSOCIATES 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)

21 21 BROOKHAVEN SCIENCE ASSOCIATES Power Outputs from Insertion Devices APS U33 2.4m produces similar power per unit solid-angle as NSLS-II IVU22 6m O. Chubar (NSLS-II)

22 22 BROOKHAVEN SCIENCE ASSOCIATES Cryogenic vs. Water Cooling of Si Optics NSLS-II min. gap: 1.8mm(h) x 0.9mm(v) Bragg angle = 14 o Absorbed Power ~113W Peak Temp: K Slope 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)

23 23 BROOKHAVEN SCIENCE ASSOCIATES 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)

24 24 BROOKHAVEN SCIENCE ASSOCIATES 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)

25 25 BROOKHAVEN SCIENCE ASSOCIATES 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)


27 27 BROOKHAVEN SCIENCE ASSOCIATES 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

28 28 BROOKHAVEN SCIENCE ASSOCIATES 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 – Leader Oleg Chubar – source properties Ruben Reininger – gratings and mirrors Lonny Berman – crystal optics and heat load Zhong Zhong – high energy x-ray monochromators Andy Broadbent – 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

29 29 BROOKHAVEN SCIENCE ASSOCIATES 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 beamlines Lonny Berman – 3-pole wiggler and bend-magnet x-ray beamlines Eric Dooryhee – Damping wiggler x-ray beamlines Andrei 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.


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