1 / 22

NSLS II: Accelerator System Overview NSLS II Advisory Committees October 18/19, 2006 Satoshi Ozaki

NSLS II: Accelerator System Overview NSLS II Advisory Committees October 18/19, 2006 Satoshi Ozaki. Introduction. NSLS II: A highly optimized, third generation, medium energy storage ring for the x-ray synchrotron radiation: The CD-0 approval articulated required capabilities as:

chun
Télécharger la présentation

NSLS II: Accelerator System Overview NSLS II Advisory Committees October 18/19, 2006 Satoshi Ozaki

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. NSLS II: Accelerator System Overview NSLS II Advisory Committees October 18/19, 2006 Satoshi Ozaki

  2. Introduction • NSLS II: A highly optimized, third generation, medium energy storage ring for the x-ray synchrotron radiation: • The CD-0 approval articulated required capabilities as: • ~ 1 nm spatial resolution, • ~ 0.1 meV energy resolution, and • single atom sensitivity (or sufficiently high brightness) • These and other requirements translate into the target parameters of the storage ring as; • ~3 GeV, 500 mA, top-up injection • Brightness ~ 7x1021 photons/sec/0.1%bw/mm2/mrad2 • Flux ~ 1016 photons/sec/0.1%bw • Ultra low-emittance (x, y): 1 nm horizontal, ~0.01 nm vertical •  20 straight sections for insertion devices ( 5 m), • A high level of reliability and stability of operation

  3. Booster Storage Ring Linac Accelerator System Configuration Booster • NSLS II Accelerator System: • 200 MeV S-band Linac • 3 GeV 1 Hz Booster • Top-up injection once per minute • 3 GeV storage ring: 30 DBA configuration • 15 long (8 m) straight with high -function • 15 short (5 m) straight with low -function Storage Ring

  4. Renderingof the NSLS II Ring (Rear View)

  5. Injector Linac • S-band linac system providing 200 MeV electron beams of 7 nC to the Booster in one pulse • Electron source: thermionic DC gun modulated to match 500 MHz RF of booster and storage ring • Five accelerating structures with three klystrons operating at 1.3 GHz • The system commercially available in turn-key procurement: • ACCEL • THALES

  6. Booster Synchrotron • 200 MeV to 3 GeV booster • Hung below the ceiling of the storage ring tunnel and has the same circumference of 780 m • The lattice arranged to have no booster components above storage ring straight sections, except for one 8-m straight for RF cavity • Relatively light weight small magnets; low power and air cooled: • 60 combined function dipoles: 1.5 m long, 25 mm gap, 0.7 T, ~580 kg • 96 quadrupoles: 0.3 m long, <10T/m, ~45 kg • 15 sextupoles: 0.4 m long, <200T/m2, ~55 kg • 15 sextupoles: 0.2 m long, <200T/m2,~30 kg • 60 orbit correctors • Up to 100 bunches per cycle for initial fill • Up to 20 bunches per cycle with the hunt-and-fill bunch pattern • One PETRA-type (commercially available) RF cavity • Very low emittance at the storage injection energy helps smooth low loss top-up injection. • Purchase components from industry based on our reference design, and build and commission in-house • Turn-key procurement of a compact booster in separate tunnel: an option

  7. Booster Lattice and its Relationship with Storage Ring

  8. Storage Ring Lattice Layout Linac RF Station

  9. Storage Ring Storage ring configuration • DBA30 lattice (780m circumference) with 15 super-periods, each ~52m long • Super-period: two identical cells separated by alternating 5m and 8m straights • Short straight: x = 2.7m, y = 0.95m, and dispersion = zero • Long straight: x = 18.2m, y = 3.1m, and dispersion = zero • This Hi-Lo  is suited for variety of ID as well as top-off injection • Weak bends (0.4T) with damping wigglers to achieve ultra-small emittance • Lattice magnet: (designed with 20% head room) • Dipoles: 60 (50 with 35 mm gap and 10 with 60 mm gap for IR beams) • Quadrupoles: 360 • Sextupoles : 390 • Correctors and skew quadrupoles: 240 + (4 X ID) • 500 MHz superconducting RF cavities each operating with 270 kW power level • Harmonic number (No. of buckets): 1300, of which ~ 80% will be filled • A 2-cell harmonic cavities for bunch lengthening Basic performances: • 3 GeV, 500 mA, Top-up with current stability of <1% • Bare Lattice: x ~2.1 nm, y ~0.008 nm (Diffraction limited at 12 keV) • Pulse Length (rms): 2.9 mm/~10 psec

  10. Lattice functions of half of an NSLS-II SR super-period (one cell).

  11. Dispersion Section of a Cell Alignment tolerance of multipoles on a girder is 30 m, whereas girder-to-girder tolerance is ~100 m In order to reduce the transmission of ground vibrations beam height is set at 1 m from the SR tunnel floor, instead of standard 1.4 m. Girder Resonant Frequency > 50 Hz

  12. Dynamic Aperture of the Lattice For on momentum and off momentum cases by 3%

  13. Horizontal Emittance vs. Energy Radiated by DW Dots represent the cases with 0, 1, 2, 3, 5, 8 damping wigglers, each 7-m long with 1.8 T field

  14. RF Power Up-grade Path RF Power Requirements for Dipole and Various Insertion Device Configurations.

  15. Ultimate Configuration and Performances Ultimate Configuration: • 8 damping wigglers (7 m long, 1.8T peak field) • 4 RF cavities with 1,080 kW of RF power Expected performances at 3 GeV: • Beam current: 500 mA • Emittance: x ~ 0.5 nm, y ~ 0.008 nm • Flux ~ 1016 photons/sec/0.1%bw • Brightness ~ 7x1021 photons/sec/0.1%bw/mm2/mrad2 • Beam Size (x/ y) at the center of short straights: ~38.5/~3.1 m • Beam Divergence (x’/y’) ~18.2/~1.8  rad • Pulse Length (rms) with damping wigglers: 4.5 mm/~15 psec • 19 user device (e.g., undulators) straights (15 x 5 m & 4 x 8 m) • 4 long straights for large gap user insertion devices • 15 short straight for user undulators, some with canting • 8 user compatible (fixed gap) damping wigglers • Many bending magnets for soft X-ray beam lines (critical energy ~2.4 keV) • Up to 5 bending magnets for IR, far-IR, and THz beamlines

  16. Baseline Configuration & Performances Proposed baseline (CDR): • 3 damping wigglers (7 m long, 1.8T peak field) • 2 RF cavities with 540 kW of RF power • 5 user beamlines (supported by trust funds) Expected performances at 3 GeV: • Beam current: step-by-step increase to 500 mA • Emittance: x ~ 1 nm, y ~ 0.008 nm • Flux ~ 1016 photons/sec/0.1%bw ? • Brightness ~ 4x1021 photons/sec/0.1%bw/mm2/mrad2 ? • Beam Size (x/ y) at the center of short straights: ~54.5/~3.1 m ? • Beam Divergence (x’/y’) ~25.7/~1.8  rad ? • Pulse Length (rms) with damping wigglers: 4.5 mm/~15 psec ? • No. of DW that can be used for light source: 3 • Max number of ID beam lines: ~10 (e.g., 6 CPMU [3 m] and 4 EPU [4 m]) • A number of bending magnets for soft X-ray beam lines (EC ~2.4 keV) • No. of IR beams from wide gap dipoles:  5

  17. Issues for Further Studies • Development of precision alignment (~30 µm) technology • Development of the optimum orbit correction and feedback scheme for high level orbit stability: • A factor of ~3 improvement over the submicron stability recently reported with some recent light sources • Impact and remediation of 5 mm gap undulator with short pitch to the dynamic aperture and the beam life-time • Because of the vertical focusing effect of undulators with short pitch, they cannot occupy the part of the ID straight where the vertical -function is large, i.e., areas away from the center of the straight • This limits the 5 mm gap undulator length to ~3 m • Impact of EPU on dynamics of the beam • Use of canted insertion device • Overall value engineering efforts

  18. Summary • Made good progress in last nine months in developing CDR for NSLS II • Optimized and define the configuration of the accelerator systems • Undertook conceptual design of accelerator systems, in some case more detailed • Assembled accelerator parameter tables • We have a innovative design of a highly optimized synchrotron light source capable of meeting requirements articulated in the CD-0 document with ultra-high performances • There are a number of issues requiring further study: • Insertion devices and their impact on the dynamic aperture and beam life-time • Diagnostics and feed-back for the required highly stable beam operation • General value engineering exercise to control costs

  19. Injector Linac Parameters

  20. Booster Ring Parameters

  21. Storage Ring Parameters

  22. Storage Ring Parameters (Continue)

More Related