1. 1 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II ASAC-2007, April. 23, 2007 Injection System with a Booster in Separate Tunnel T. Shaftan for the NSLS-II team

2. 2 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II ASAC-2007, April. 23, 2007 Outline Summary of NSLS-II injection requirements Ring injection straight Injection simulations New injector layout 200-MeV linac 3.0-GeV booster Injector tunnel Challenges Conclusion

3. 3 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II ASAC-2007, April. 23, 2007 Summary of NSLS-II injection requirements High reliability Reasonable initial fill time Low losses Low power consumption Lifetime 3 hours (with 3 rd HC) Top-off  Stability of current <1 %  Time between top-off injections >1 min  Bunch-to-bunch variations of charge <20%  Storage ring: 7.3 nC per 1 min; top-off format: 1-2 shots per 1 min  Linac: 15 nC in 1 min (50% losses), THALES linac: 9.3 nC/300 ns  Bunch train: 80 – 300 ns long (40 – 150 ring buckets) Ī t Ī t QIQI t IbIb bunch #

4. 4 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II ASAC-2007, April. 23, 2007 Injection straight-section Closed non-interleaved bump design Fits into a single straight section of the ring 2-turn long pulsed kickers Optimization of the injected beam Twiss parameters Sufficient tolerances for injected and stored beam Minimization of injection transients effect on stored beam Δ=15 mm 6.4 m 0.6 m 1.9 m 0.3 m 0.1 m 0.85 m Septum “knife” I 3  inj 4 mm 10  stor + +2 mm COE 3 mm Closed bump design Injection geometry near septum stored beam t 1 st turn2 nd turn3 rd turn  kicker with I. Pinayev, R. Heese

5. 5 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II ASAC-2007, April. 23, 2007 Simulations of injection into the ring Courtesy of L.H. Yu and I. Pinayev 200 particles, 10000 turns RF is ON, synch rad is ON Transverse misalign. are ON Multipole field errors Realistic apertures included Orbit correction Tune correction Coupling correction (in TRACY-2) Injected beam with optimum beta- functions No IDs yet Injection tracking with emittances of 35 at 3 GeV No limitations from DA (DA is larger then vacuum chamber size) Sufficient tolerances for injection into the ring are observed

6. 6 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II ASAC-2007, April. 23, 2007 Injector layout with compact booster ASAC-2006: in-tunnel booster Lehman Review 2007: recommendation for choosing compact booster Diamond, Soleil, BESSY, APS, ALS, …; low-emittance solution – ASP booster Reworking the ASP booster lattice: headroom for 3.6 GeV Minimum of modifications: cost-effective solution Higher current (~30 mA), longer bunch trains, injection at 200 MeV

7. 7 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II ASAC-2007, April. 23, 2007 200-MeV linac 3-GHz 100-MeV linac from THALES is in operations at SOLEIL SOLEIL gun operates at 352 MHz, we need 500 MHz We need 15 nC in 80-300 ns at 200 MeV Assume 50% losses in the booster-ring bucket Higher energy reduces beam loading and energy spread, eases booster injection Higher energy provides with redundancy: loss of a klystron  booster injection at 177 MeV Need for flexible bunch train format Measured valueLPMSPM Pulses1004 Pulse length, ns2861.3 Energy, MeV108110 Charge, nC9.32.15 Emittance X/Y, μm (4  ’) 47/5267/78 Energy spread, %  0.5  0.82 Measured beam trains in LPM (SOLEIL) from: HELIOS, THE LINAC INJECTOR OF SOLEIL: INSTALLATION AND FIRST RESULTS, PAC-2005 J. Rose

8. 8 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II ASAC-2007, April. 23, 2007 3 GeV booster NSLS-II Booster parameters: –Emittance 35.2 nm (at 3 GeV) –Circumference 143.96 m –Tunes 10.3/3.27 –Chromaticity 10.41/13.27 –Momentum Compaction 0.0081 –Loss per turn 625 keV –Damping times x/y/E, 5.0/4.6/2.2 ms –Energy spread/Bunch length 0.078%/14 ps –RF Voltage 1.2 MV –Beam current, 31 mA Combined-function FODO: 32 BDs and 28 BFs ½ of booster lattice with W. Guo, J. Skaritka, R. Maier

9. 9 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II ASAC-2007, April. 23, 2007 Lower level Upper level Tunnel of ~150m circumference Same elevation as storage ring Earthen berm on top and sides Lower level: accelerators Upper level: service areas, power supplies, RF, vacuum supplies, controls Injector building may be shifted by 1 superperiod clockwise Total injection system power consumption –600 kW at 1 Hz –~200 kW in top-off Injector tunnel

10. 10 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II ASAC-2007, April. 23, 2007 Challenges Evaluation of losses at booster injection Passing long bunch trains through the injector (flat-top of kickers) “Hunt and peck” mode of injection Single-bunch versus multi-bunch for complex bunch patterns Minimization of injection transients in stored beam: Closing injection bump (feedback with additional weak kickers) Individual versus in-series PS for kickers for reduction of injection transient

11. 11 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II ASAC-2007, April. 23, 2007 Conclusions Injector with “compact” booster is under development 200-MeV linac will provide with high charge per pulse in flexible bunch trains Low emittance booster lattice is chosen (35 nm at 3 GeV, 49 nm at 3.6 GeV), supported by simulations of injection process into Storage Ring TRACY-2 and ELEGANT Linac and booster ring (w/o RF) are turn-key procurements with some modifications from original design; transport lines and injection straight section by BNL Increase in injector cost (~7 M$) due to the booster building

12. 12 BROOKHAVEN SCIENCE ASSOCIATES NSLS-II ASAC-2007, April. 23, 2007 Future work Refinement of ring injection tracking (including IDs, 3.6 GeV, etc.), simulations of injection into the booster at low energy, evaluation of losses throughout injector, short bunch train analysis (beam loading), minimization of transients in the ring injection straight design, availability analysis.