NSLSII Photon Sources Beamline Systems Qun Shen Director
NSLS-II Photon Sources & Beamline Systems Qun Shen Director, Experimental Facilities Division (XFD) NSLS-II Beamline Development Information Meeting April 14, 2010 Email: qshen@bnl. gov 1 BROOKHAVEN SCIENCE
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 2 BROOKHAVEN SCIENCE
Design Parameters of NSLS-II Storage Ring NSLS-II Design Parameters Overview of one super period of NSLS-II storage ring Ring energy (Ge. V) 3 Ring current (m. A) 500 Ring circumference (m) 792 Number of DBA cells 30 Number of 9. 3 m straights 15 Number of 6. 6 m straights 15 bh in 9. 3 m straights (m) 20. 1 bv in 9. 3 m straights (m) 3. 4 bh in 6. 6 m straights (m) 1. 8 bv 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 (ms) 2. 64 Number of bunches 1056 Average bunch current (m. A) 0. 47 Average bunch charge (n. C) BROOKHAVEN 1. 25 SCIENCE 3
Typical Sector Layout at NSLS-II D I b w BM / W Lo 3 P 4 b High- ID 3 PW / BM BROOKHAVEN SCIENCE
Electron Source Size sh, v and Divergence s’h, v Type of source σh (μm) σh' (μrad) σv (μm) σv' (μrad) High-b Straight Section (9. 3 m) Low-b Straight Section (6. 6 m) 33. 3 16. 5 2. 9 2. 7 High-b Straight Section (9. 3 m) 107 5. 1 5. 2 1. 5 3 -pole Wiggler Bending Magnet 5 0. 4 T Bend Magnet 125 91 13. 4 0. 80 1. 14 T 3 -Pole Wiggler 167 98 12. 3 0. 82 Low-b Straight Section (6. 6 m) BROOKHAVEN SCIENCE
Six Beamlines in NSLS-II Construction Project • Inelastic X-ray Scattering (IXS) CSX 23 ID XPD 28 -ID • Hard X-ray Nanoprobe (HXN) • Coherent Hard X-ray Scattering (CHX) SRX 21 ID • Coherent Soft X-ray Scattering & Polarization (CSX) CHX 5 -ID HX N 3 ID IXS 10 -ID 6 • Sub-micron Resolution X- ray Spectroscopy (SRX) Note: beamline location • X-ray Powder Diffraction assignments preliminary (XPD) Conceptual design report posted at http: //www. bnl. gov/nsls 2/docs/ PDF/ BROOKHAVEN SCIENCE
Currently Planned Insertion Devices at NSLS-II Type of Device Purpose Quantit y Damping Wiggler (DW 90): 90 mm period, 1. 85 T, 2× 3. 5 m Broadban d In-Vacuum Undulators (IVU): IVU 20: 20 -mm period, 1. 05 T (> 5 mm gap), 3 m IVU 21: 21 -mm period, 0. 91 T (> 5. 5 mm gap), 1. 5 m, canted IVU 22: 22 -mm period, 0. 76 T (> 7 mm gap), 2× 3 m (tentative) Hard Xray Elliptically-polarizing undulator (EPU 49): 49 -mm period, • Undulators can begap), canted 0. 94 T (> 11. 5 mm 2× 2 by m 0 -2 long, mrad optionally canted by in bothmrad low-b and high-b straight ~0. 16 Soft X-ray sections Three-Pole Wiggler: 1. 14 T peak field, 20 -cm long • DWs can also be canted but requires modification of vacuum chamber 7 3 2 1 1 1 Canting angle 0 -2 mrad Broadban 1 d BROOKHAVEN SCIENCE
Current and Potential Insertion Devices at NSLS-II Type Photon energy range [ke. V] U 20 U 22 U 17* U 14* EPU 49 DW 90 SCW 60 BM 3 PW IVU CPMU SCU EPU PMW SCW Bend PMW 1. 9– <0. 01– <0. 01 1. 8 -20 2. 1 -25 1. 8 -40 0. 18– 7 20 100 200 12 – 25 Type of straight section Low-β High-β Low-β Period length, l. U [mm] 20 22 17 14 49 90 60 Total 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. 5 Minimum magnetic gap 5 7 5 5 11. 5 12. 5 15 28 [mm] Peak field linear mode B 1. 03 0. 74 ~1. 1 ~1. 7 0. 94 1. 85 3. 5 0. 40 1. 14 [T] Max Ky in linear mode 1. 83 1. 52 ~1. 7 ~2. 2 4. 34 15. 7 19. 6 Peak field circular mode 0. 57 B [T] Max K= 2 Ky in circular 3. 69 mode Min. hn fundamental 1. 6 1. 8 ~2. 1 ~1. 8 0. 17 [ke. V] Critical energy [ke. V] 11. 1 21 2. 39 6. 8 * Requirestotal additional with CPMU 17 as near-term and options SCIENCE 8 ~16 Maximum power R&D, 7. 9 9. 1 ~9. 2 8. 8 SCU 14 67 as far-term 34 BROOKHAVEN 0. 32
Spectral Brightness of NSLS-II Sources at 500 m. A 9 BROOKHAVEN SCIENCE
Spectral Flux of NSLS-II Sources at 500 m. A 10 BROOKHAVEN SCIENCE
Spectral Flux of NSLS-II Sources (cont’d) 11 BROOKHAVEN SCIENCE
Wiggler Comparisons 12 BROOKHAVEN SCIENCE
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 13 BROOKHAVEN SCIENCE
Optimization of Undulator Performance Given Accelerator Constraints Radia Model (central part) IVU Parameters Reference Geometry: O. Chubar (NSLS -II) Materials: Pole Width: 40 mm. Magnet Width: 50 Pole: Va Permendur Pole Height: 25 mm mm NEOMAX Pole Thickness: 3 mm Magnet Height: 29 Magnet: Nd. Fe. B (for λu = 20 mm) mm Fundamental Photon Energy vs Gap for Different IVU Periods (E = 3 Ge. V) IVU Lengths Satisfying Vertical “Stay Clear” Constraints in Lowand High-Beta Straight Sections λu= 23 mm λu= 22 mm βy 0 = 3. 4 m λu= 20 mm λu= 21 mm βy 0 = 1. 06 m 14 BROOKHAVEN SCIENCE
Spectral Flux of Different IVUs – IXS “Candidates” – Satisfying e-Beam Vertical Clear” Maximal Spectral Flux through 100 μrad (H) x“Stay 50 μrad (V) Aperture Constraint E-Beam Energy: 3 Ge. V Current: 0. 5 A NSLS-II High-Beta (Long) Straight Section ~9. 13 ke. V • Such insertion device optimization is done during conceptual design O. Chubar (NSLS -II) • Not necessary ~9. 13 ke. V 15 for beamline development proposal BROOKHAVEN SCIENCE
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 -1. 5 mrad 0 mrad 3 PW BM-A BM-B +2. 125 mrad +2. 5 mrad +4. 25 mrad 16 BROOKHAVEN SCIENCE
3 PW and BM Power Density Distributions Magnetic Field 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 =θ 0) |θ | = 4. 25 mrad |θ | ≈ 2. 6 mrad =0 X X X 1. 65 mrad O. Chubar (NSLSII) 17 BROOKHAVEN SCIENCE
3 PW and BM Intensity Distributions (Hard Xrays) • Intensity distributions at different photon energies at 30 m from 3 PW show effects from soft poles in 3 PW and from adjacent BMs • Effect of such non-ideal intensity distribution on microfocusing is being studied by a working group, and updates will be. O. provided Chubar (NSLSII) at x = 0 Vertical Cuts Horizontal Cuts at y = 0 18 BROOKHAVEN SCIENCE
Beamline Systems Overview Endstation and experiment controls Utilities and safety system (PSS, EPS) Enclosures and beam transport Front-end (inside storage ring tunnel) Photon optical system 19 BROOKHAVEN SCIENCE
Optical Systems • 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) HXN Beamline Optical Layout (top view) Yong Chu (NSLS-I 20 BROOKHAVEN SCIENCE
Power Outputs from Insertion Devices • APS U 33 2. 4 m produces similar O. Chubar (NSLS-II) power per unit solid-angle as NSLS-II IVU 22 6 m 21 BROOKHAVEN SCIENCE
Cryogenic vs. Water Cooling of Si Optics NSLS-II U 20 @ min. gap: 1. 8 mm(h) x 0. 9 mm(v) Bragg angle = 14 o Absorbed Power ~113 W Peak Temp: 116. 5 K Slope Error: 0. 4 mrad (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 3 PW/BM sources 22 V. Ravindranath (NSLS-II) BROOKHAVEN SCIENCE
Variety of Cutting-Edge Focusing X-ray Optics • Kirkpatrick-Baez (K-B) mirrors • Large acceptance aperture, achromatic focusing for easy energy scanning • Focal size limited by critical angle: achieved ~25 nm – XRF imaging of a test Above • Compound Refractive Lens • pattern, scanned through 2 D focusing by crossed MLL, with lenses resolution ~20 nm x 40 nm • Refraction effect is weak so requires many • Shape errors affect focal size: achieved ~50 nm Yan, Conley, Lima et al. (NSLS-II) Conventional Fresnel zone plate (FZP) Maser, Macrander, Shu et al. (ANL) • 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 (1 D) 23 BROOKHAVEN SCIENCE
Canted Beamline Example: SRX Beamline KB branch Thieme et al. (NSLS-II) ZP branch • Two x-ray branches using two ~1. 5 m long U 21 -type undulators canted by 2 mrad • Two hor. mirrors to deflect ZP beam out to allow ~0. 5 m separation in ZP hutch BROOKHAVEN SCIENCE 24
Coherent Soft X-ray Beamline Full polarization control branch Sanchez-Hanke, Reininger, et al. (NSLSII) Coherent branch • Two soft x-ray branches using 2 x EPUs canted by 0. 16 mrad • Branching mirror M 1 A to deflect beam outward for the coherent branch 25 BROOKHAVEN SCIENCE
NSLS-II Project Beamline Schedule 26 BROOKHAVEN SCIENCE
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 27 BROOKHAVEN SCIENCE
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 (hulbert@bnl. gov) – Leader Oleg Chubar (chubar@bnl. gov) – source properties Ruben Reininger (rreininger@bnl. gov) – gratings and mirrors Lonny Berman (berman@bnl. gov) – crystal optics and heat load Zhong (zhong@bnl. gov) – high energy x-ray monochromators Andy Broadbent (broadbent@bnl. gov) – utilities and safety systems • Group meets weekly to discuss any issues that requires attention; XFD Director participates in these meetings to provide 28 additional information as oversight and to communicate any BROOKHAVEN SCIENCE
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. 29 BROOKHAVEN SCIENCE
Thank You! Questions ? ? 30 BROOKHAVEN SCIENCE
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