1. 1 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II Accelerator Systems Advisory Committee, July 17-18, 2008 NSLS-II Injection System T. Shaftan Accelerator Physicist NSLS-II Accelerator Systems Advisory Committee July 17-18, 2008

2. 2 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II Accelerator Systems Advisory Committee, July 17-18, 2008 Acknowledgements R. Heese, J. Rose, N. Tsoupas, I. Pinayev, S. Ozaki, F. Willeke, E. Weihreter, Y. Li, W. Guo, B. Nash, M. Fallier, M. Ferreira, R. Alforque, S. Krinsky, E. Johnson, A. Blednykh, O. Dyling, R. Meier, S. Sharma, D. Hseuh, G. Ganetis, T. Shaftan, O. Singh, J. Skaritka, M. Rehak, J. O ’ Connor, C. Lavelle, P.K. Job, B. Casey, T. Mennona

3. 3 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II Accelerator Systems Advisory Committee, July 17-18, 2008 Outline Introduction Injector design specifications and main parameters Injector layout Linac Booster Transport lines Storage Ring injection straight section Summary Future plans

4. 4 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II Accelerator Systems Advisory Committee, July 17-18, 2008 Introduction NSLS-II requires reliable injector capable of filling and maintaining storage ring current Top-off mode of injection is required More detailed design has been developed on preliminary design of 200 MeV linac and 158 m 3 GeV booster presented at the ASAC in Oct. 2008 Linac and booster are envisioned as semi-turnkey procurements Transport lines and ring injection straight are going to be built by BNL

5. 5 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II Accelerator Systems Advisory Committee, July 17-18, 2008 Storage Ring Parameters Related to Injection ParametersValue Energy, GeV3 Circulating current, A0.5 Circumference, m792 Revolution period,  s 2.6 RF frequency, MHz500 Circulating charge,  C 1.3 Total number of RF-buckets1320 Number of filled buckets 1320  4/5  1080 Charge per bunch, nC1.25 Beam lifetime, hours3 Top-up cycle time, min1 Beam current change between top-ups, %0.55% Charge variation between top-up cycles, nC7.3

6. 6 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II Accelerator Systems Advisory Committee, July 17-18, 2008 Requirements for NSLS-II Injection  Discussed with users on their desired bunch patterns and top-off formats  Two bunch patterns are in NSLS-II baseline:  4 or 5 bunch trains with shorter gaps totaling about 80% of the full buckets  uniform fill with 20% ion-clearing gap  Complex bunch patterns (camshaft bunches or 100% uniform fill) are not precluded and foreseen as future upgrades. Current stability and purity  Relative current stability of 1% is the baseline number.  Charge in empty bucket <10 -4 x nominal charge  Minimum interval between two consecutive top- off is 1 min.  Gating signal to users is to be provided. NSLS-II bunch patterns 4/5 1/5 I t I t 1 turn I inj 1min t NSLS-II top-off format

7. 7 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II Accelerator Systems Advisory Committee, July 17-18, 2008 Many (~1000) bunches in the ring  multi- bunch injection N M bunches in the injected train Filling N M consecutive buckets in the ring Sequentially shift the injection timing 1 Hz injector rep rate suffices with pulse train injection 1 minute between injector cycles for top-off Interacting with users on the requirements for top-off and complex bunch patterns Developed simulation on SR pattern non-uniformity Evaluated rate of contamination of “empty” buckets by Touschek- scattered particles Injected bunch train ( N M =80-150) t # Ring bunch pattern IbIb Top-Off Injection Scenario 80 bunches in injected train 150 bunches in injected train

8. 8 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II Accelerator Systems Advisory Committee, July 17-18, 2008 NSLS-II Injector Complex Overview 200-MeV linac 3-GeV booster LB TL B-SR TL Injection straight

9. 9 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II Accelerator Systems Advisory Committee, July 17-18, 2008 Linac SR injection: 7.3 nC/min 10% loss at SR injection 20% loss at booster extraction 30% beam loss at booster injection  15 nC per pulse NSLS-II: 200 MeV, 15 nC/train, ~0.5% energy spread Linac can be procured turn-key January 2008 we visited SOLEIL and THALES Acquired information regarding linac hardware, utilities and performance Acquired information on beam measurement data Participated in linac studies SOLEIL measurement of injected bunch train SOLEIL linac J. Rose

10. 10 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II Accelerator Systems Advisory Committee, July 17-18, 2008 Linac Configuration  3 GHz, 100 MeV linac is in operations at ASP (ACCEL)  3 GHz, 100 MeV linac is in operations at SOLEIL (THALES)  Achieved parameters:  4/0.25 nC/pulse in LPM/SPM at ASP  10/0.5 nC/pulse in LPM/SPM at SOLEIL  Close to NSLS-II requirements  Linac Front-End funding is planned in FY09 to procure and establish gun performance Thales linac J. Rose, R. Meier

11. 11 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II Accelerator Systems Advisory Committee, July 17-18, 2008 Booster Booster accelerates beam from 200 MeV  3 GeV Tracking studies have been carried out with nearly complete ring model: booster emittance of ~30 nm is adequate for low- loss injection Compact (158.4 m) and low-emittance (30 nm at 3 GeV) lattice Accelerates bunch trains Repetition rate of 1 Hz Charge per train 10 nC RF system (by BNL): PETRA cavity and IOT Optimized injection and extraction systems: DC septa Semi turn-key procurement that is close to existing solution Lattice Similar to Australian Synchrotron Project booster Structure Acknowledge work of W. Guo, Y. Li, B. Nash

12. 12 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II Accelerator Systems Advisory Committee, July 17-18, 2008 Progress on booster lattice CD2  New lattice version Similar magnet parameters as in CD2 lattice Straight section length increased 7.05  7.7 m Vertical tune (and chromaticity) is decreased DA (on- and off-energy) is increased to larger than vacuum chamber aperture Dispersion in straight decreased to 10 cm Emittance is 33 nm at 3 GeV – needs more work Orbit correction scheme is adequate 20 mA in the booster: study of collective effects is under way Dynamic aperture Dipole physical aperture Y. Li

13. 13 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II Accelerator Systems Advisory Committee, July 17-18, 2008 Optimization of booster extraction and injection systems CD-2 A single pulsed septum 150 mrad Assume beam divergence of 80 urad (horizontal) at extraction RMS beam divergence = error at: Kicker stability (flatness) of 1.6% Septum stability (flatness) of 0.05%  Reducing sensitivity to waveform jitter and noise CD-3 Combination of weak pulsed septum (47 mrad) and DC septum (96 mrad) Kicker stability (flatness) of 1.6% Septum stability (flatness) of 0.2% QF QG QF B B B B DC septum kicker pulsed septum B B B B kicker pulsed septum QF QG QF

14. 14 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II Accelerator Systems Advisory Committee, July 17-18, 2008 Magnet design DC extraction septum Transport line quadrupole M. Rehak, R. Heese Magnet definition is in progress for injector: LB TL: 4 dipoles, 14 quadrupoles Booster injection and extraction system BSR TL: 4 dipoles, 16 quadrupoles Injection straight: pulsed magnets Transport lines: Quadrupoles: 2 type of yokes, 3 types of different coils Dipoles: 3 types of yokes, 3 types of coils Correctors: 2 types of yokes, 2 types of coils Complex magnets: DC extraction and SR injection septa Soon start magnetic design of pulsed magnets

15. 15 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II Accelerator Systems Advisory Committee, July 17-18, 2008 Layout of LB TL In the past months:  SOLEIL experience: energy slit after linac is very helpful  Redesigning LB TL to increase dispersion at energy slit  New booster injection scheme is implemented  Beam optics is complete  Local shielding design is under way  Diagnostics beam lines are to be designed ES R. Heese, R. Meier

16. 16 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II Accelerator Systems Advisory Committee, July 17-18, 2008 Booster to Storage Ring Transport Line In the past months:  Addressed all incompatibility between TL and building  New booster extraction scheme is implemented in the BSR TL  Beam optics complete  Placement of corrector magnets, and beam diagnostic devices complete  Tolerance studies complete  Diagnostics beam line is being designed N. Tsoupas, R. Meier

17. 17 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II Accelerator Systems Advisory Committee, July 17-18, 2008 Storage ring injection straight Quad-to-quad distance is 9.3 m Combination of strong DC pre-septum with pulsed septum Closed bump of 15 mm Kickers with 5.2 μs long pulse powered separately Pulsed magnets (3.15 GeV max) are within vendors capabilities Magnet and PS design is under way Development and optimization of pulsed magnets and PS (total of 13 magnets of 7 types for NSLS-II) in-house: Pulsed Magnet Lab in FY09 R. Heese, M. Ferreira, D. Hseuh

18. 18 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II Accelerator Systems Advisory Committee, July 17-18, 2008 Pulsed magnet tolerance analysis Study of the residual field errors in closed bump (for the maximum stored beam displacement) Vertical error: random kicker roll of 0.5 mrad (  3.75 µ rad angular vertical kick) Horizontal error: 0.1% kicker-to-kicker random amplitude mismatch Consider combination of 4 kickers and scale total to the Source Points of Short and Long Straight sections Compare with RMS beam size and divergence at the Source Points Horizontal error is of order of RMS beam parameters Vertical error exceeds RMS parameters Need set-up of Pulsed Magnet Lab to develop methods of error reduction Tolerance analysis is ongoing Horizontal error scaling for kicker mismatch Vertical error scaling for residual kicker roll Orbit angle at SP (µrad) Orbit shift at SP (µm)

19. 19 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II Accelerator Systems Advisory Committee, July 17-18, 2008 Injector building 1 2 3 4 5 6 7 8 9 10 11 13 12 14 15 16 17 18 N Supplemental shielding Penetration Safety device Cabling Entrance

20. 20 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II Accelerator Systems Advisory Committee, July 17-18, 2008 Utilities, injector components, safety Multiple iterations on building layout 80% Title II Design complete Injector utilities (electric power, water, compressed gas) are specified Injector components Booster Power Supplies performance specs established Injector element specification is in progress Injector magnet design and PS specs are in progress Cable/signal list is compiled Component naming convention to be discussed Safety review took place Assessed beam parameters envelope Assessed beam confinement system Design of safety devices is under way NSLS-II beam dump design APS safety shutter R. Alforque

21. 21 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II Accelerator Systems Advisory Committee, July 17-18, 2008 Procurements Linac: visited THALES and SOLEIL in January Linac Front-End to be procured in FY09 Booster RF: visited DESY in July Booster: two potential vendors visited NSLS-II in January and March Booster Statement of Work completed in April Information on: Scope of delivery Timeline Performance specifications Acceptance testing Conventional constructions Mechanical and Electrical utilities Diagnostics and Controls Norms and Standards Booster SOW was sent to three potential vendors for budgetary quotes and schedules Expecting information from two vendors in August

22. 22 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II Accelerator Systems Advisory Committee, July 17-18, 2008 Summary NSLS-II full energy injector will support top-off operations in presence of limited beam lifetime Multi-bunch injection with high charge per bunch train Linac and booster are envisioned as major procurements NSLS-II booster is based on existing design (low-emittance cost-effective solution) with modifications We are moving forward with design of injection straight section and transport lines In the design process we use experience from other state-of-art light sources In the past months injector development was focused on: Finalizing injector building specifications Setting specifications on utilities, safety systems, interfaces with NSLS-II subsystems Optimization of the booster lattice, injection/extraction systems Transport line design and specification of components Design of the storage ring injection straight Interaction with vendors Draft of CD-3 Design Report is nearly ready

23. 23 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II Accelerator Systems Advisory Committee, July 17-18, 2008 Important dates for NSLS-II injector CD-2: injection system baseline design is developed During FY08-FY09 we are refining design and perform value engineering effort, prepare specs for procurements Specifications are ready for procurement: LinacOct 09 Booster Aug 09 Booster RFAug 11 UtilitiesDec 10 TLMar 10 At this point the design and specs by BNL are finalized Procurement begins: LinacOct 10 Booster Mar 10 TLApr 10 UtilitiesNov 09 Injector Building BOD end Nov 11

24. 24 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II Accelerator Systems Advisory Committee, July 17-18, 2008 Extra

25. 25 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II Accelerator Systems Advisory Committee, July 17-18, 2008 Uniformity of bunch pattern Requirement on SR bunch pattern uniformity is 20% Can we preserve the uniformity while executing top-off with bunch trains? “ Hunt&Peck ” mode of injection at SLS Simulation with assumptions: Touschek-limited lifetime Phase transient induced by harmonic cavity Noisy (20%) injected bunch train Filling consecutive N=80 … 150 buckets in one top-off cycle Results after 2 days of continuous top-off show no deterioration of bunch pattern “ Hunt&Peck ” mode with bunch trains to be studied 80 bunches in injected train 150 bunches in injected train

26. 26 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II Accelerator Systems Advisory Committee, July 17-18, 2008 Maintaining purity of “ empty ” RF buckets  To maintain the purity of empty buckets on 1E-4 level we will need to do cleaning ~every 3 min  Very first energy band is located at 4.3% off the nominal energy.  This is a pessimistic estimate assuming no limits on machine energy acceptance. Real energy acceptance (limited by a scraper) will reduce migration rate.  This analysis includes only Touschek-scattered particles migrating from full to empty buckets. In reality there will be additional particles coming from injected beam every top-off cycle.  Needs an analysis of the bunch cleaner in the booster.

27. 27 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II Accelerator Systems Advisory Committee, July 17-18, 2008 Booster RF System Signed MOU with DESY for two 5-cell PETRA cavities, to be delivered in early FY2009 Need to work out coupler interface