Beam Dynamics of Energy Recovering Linacs

Transcription

1 Beam Dynamics of Energy Recoverg Lacs S.A. Bogacz, G.A. Krafft, S. DeSilva and R. Gamage Jefferson Lab and Old Domion University Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24, 216 1

2 Outle Prciple of Energy Recoverg Lacs Historical overview First ideas and tests Projects and facilities worldwide Applications of ERLs Colliders Light sources Electron Coolg of Ions Challenges Transverse/Longitudal Optics Multi-pass ERL topologies Beam Breakup Instability Nonlear Effects Summary and Outlook D. Douglas, Jefferson Lab, CASA, 215 A. Jankowiak, Humboldt University Berl, CAS 215. Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24, 216 2

3 recovery RF-fields brakg the DC limit Energy Recovery Fundamental Idea l Rf E Out = E Inj E Inj L = n l + l / 2 E = E Inj + DE (b ~ 1) Energy Flow = Acceleration Energy Storage the beam (loss free) Energy Recovery = Deceleration Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24, 216 3

4 Prciple of Energy Recoverg Lac Dump E dump ~ 1 MeV I ~ 1 ma 1 A P ~ 1 kw - MW Experiments need high beam power (MW to GW) and RF Lac (super conductg) Acceleration up to many GeV Acceleration: energy transfer to the beam E Supply of ever fresh beam E Inj ~ 1 MeV I ~ 1 ma 1 A P ~ 1 kw - MW Injector E Deceleration: energy recovery, to be used by freshly accelerated beam Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24, 216 4

5 History First Idea Nuovo Cimento, 37, 1228 (1965) Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24, 216 5

6 History First Test The Chalk River Reflexotron Schriber, Funk, Hodge, Hucheon, PAC1977, Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24, 216 6

7 History First Demonstration MIT Bates Recirculated Lac (2.857GHz, nc, pulsed), 1985 J.B. Flanz et al., IEEE Trans. Nucl. Sci., NS-32, No.5, p.3213 (1985) Stanford SCA/FEL, 7/1987 (sc-fel driver) 5MeV T. I. Smith, et al., NIM A259, 1 (1987) 15mA 5MeV Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24, 216 7

8 Storage Rgs vs Lacs ID STORAGE RING IP X-Rays Driven by different mechanism of emittance evolution Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24, 216 8

9 Radiation Dampg ID X-Rays STORAGE RING IP p itial y electron emits a photon Photon p y s pitial - p y p y - p it looses momentum (also transverse) y s RF Cavity E pitial - p y - y p - p p y s RF longitudal momentum restored by acceleratg cavity angle and displacement reduced transverse emittance reduced Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24, 216 9

10 Radiation Heatg ID X-Rays STORAGE RING IP emission of a photon at position with dispersion (e.g. a dipole, where the transverse position is energy dependent) electron oscillates around reference orbit emittance crease E E - DE reference orbit dispersion orbit for particle with energy deviation Transverse emittance is defed by an equilibrium between these two processes (dampg and heatg) Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24, 216 1

11 Adiabatic Dampg LINEAR ACCELERATOR Source ID X-Rays e e IP RF Cavity p itial y py E electron has itial transverse momentum pitial - p y - y longitudal component creases durg acceleration p - p p angle reduces with acceleration, emittance shrks: Beam quality is defed by the source, the rest is a proper acceleration and phase-space control. y RF e e Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,

12 Storage Rgs vs Lacs ID STORAGE RING IP X-Rays beam parameters defed by equilibrium many user stations limited flexibility multi-pass high average beam power (A, multi GeV) typically long bunches (2 ps 2 ps) beam parameters defed by source low number of user stations high flexibility sgle pass limited average beam power (<< ma) possible short bunches (sub psec) Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,

13 ERLs The best of both worlds LINEAR ACCELERATOR ID X-Rays ID STORAGE RING IP Source IP X-Rays ENERGY RECOVERY LINAC ID IP X-Rays Ma Lac Source High average beam power (multi some 1 ma) for sgle pass experiments, excellent beam parameters, high flexibility, multi user facility Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,

14 ERL as a Next Generation Light source dump ma lac: several GeV electron source Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,

15 Light source ERLs The best of both worlds Combes the amenities of storage rgs and lacs with energy recovery: some many GeV possible always fresh electrons (no equilibrium) small emittance (~.1 mm rad norm. = 1 pm rad@6gev) high brilliance ( x 1 1 compared to storage rgs) short pulses ( ps down to 1 1 fs) flexible choice of polarization 1% coherence up to hard X-rays real multi-user operation at many beam les tailored optics at each sertion device Flexible modes of operation (high brilliance, short pulse, different pulse patterns) adaptable to user requirements! Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,

16 Electron Cooler for Ion Beams Electrostatic,e.g. Van-de-Graaff, Peletron,... first devices the 7ies e - - source, acceleration +4.3MV DC Cold electron beam always fresh electrons collector deceleration +4.3MV Hot ion beam storage rg v Electron = v Ion e.g. FermiLab recycler rg (Tevatron) anti protons: E = 9 GeV b =.994 electrons: E = 4.9 MeV U Cooler = 4.39 MV I =.5A (DC) P = 2.2 MW Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,

17 ERL Configurations DE Sgle Lac DE/2 Racetrack DE/2 Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,

18 CEBAF ERL Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,

19 CEBAF ERL Ds = l/2 Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,

20 CEBAF ERL.75 GeV/pass.75 GeV/pass 85 MeV Ds = l/ GeV Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24, 216 2

21 CEBAF ERL Ds = l/2 Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,

22 CEBAF ERL 9:1 98.9% ERL h ERL = E j /E fal Ds = l/2 85 MeV Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,

23 5 BETA_X&Y[m] 5 BETA_X&Y[m] Lacs Optics Lowest pass E j NL (75 MeV) E 1 E j SL (75 MeV) E 1 NL BETA_X BETA_Y DISP_X DISP_Y E j E 1 SL BETA_X BETA_Y DISP_X DISP_Y E 1 Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24, E j

24 BETA_X&Y[m] 4 Multi-pass ER Optics Arc 2,4,6,8,A M2 M1 E NL j E 1 E 2 E 1 M 2 M1 E 2 SL E 1 E j E 1 E 2 Arc 1,3,5,7,9 M bx x - x x by y - y y NL SL 12 FODO M 1 1 Arc 2,4,6,8,A M 2 M2 M M 3 2 BETA_X BETA_Y DISP_X DISP_Y Acceleration/Deceleration E NL j E 1 M 4 E 2 E 1 M M1 5 M1 E 2 SL E 1 E j E 1 M 6 M E 2 7 Arc 1,3,5,7,9 M 8 M M 1 E 1 E 2 E 3 E 4 E 5 E j E 7 E 8 E 9 E 1 E 6 5 Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,

25 Lacs Optics Optimization Criteria The optimization of the lac optics aims at mitigatg the impact of imperfections and collective effects such as wake-fields driven by: mimize Free parameters: Input optics functions (β function and its derivative) Quads Strength profile One should also consider the teraction of bunches at different passes, resultg the tegrals: where the energy and the β functions need to be evaluated for the different pass numbers: i, j mimize Merit function (3-pass) Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,

26 3 BETA_X&Y[m] Optimized Multi-pass ER Optics DISP_X&Y[m] Drift Lac Acceleration/Deceleration M M 1 2 M3 M M 4 5 M6 M M 7 8 M9 1 M BETA_X BETA_Y DISP_X DISP_Y E 1 E 2 E 3 E 4 E 5 E j E 7 E 8 E 9 E 1 E 6 The quadrupole strength profile needs to be optimized order to mimize the impact of imperfections and collective effects such as wake-fields, driven by the followg parameter b 1 b ds E L E m Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,

27 BETA_X&Y[m] 3 3 BETA_X&Y[m] Optimized Multi-pass ER Optics DISP_X&Y[m] Drift Lac Acceleration/Deceleration M M 1 2 M3 M M 4 5 M6 M M 7 8 M9 1 M BETA_X BETA_Y DISP_X DISP_Y E 4 E 5 E j E 7 E 8 E 9 E 1 E 1 E 2 E 3 E 6 6 FODO M2 M3 M4 M5 M6 M M M M M1 b 1 b ds E L E m BETA_X BETA_Y DISP_X DISP_Y E 1 E 2 E 3 E 4 E 5 E j E 7 E 8 E 9 E 1 E 6 Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,

28 BETA_X&Y[m] 3 BETA_X&Y[m] DISP_X&Y[m] 3 Optimized Multi-pass ER Optics Drift Lac Acceleration/Deceleration M M 1 2 M3 M M 4 5 M6 M M 7 8 M9 1 M BETA_X BETA_Y DISP_X DISP_Y E 1 E 2 E 3 E 4 E 5 E j E 7 E 8 E 9 E 1 E 6 3 FODO M3 M M 4 5 M M 6 7 M M M M M1 2 BETA_X BETA_Y DISP_X DISP_Y b 1 b ds E L E m E 1 E 2 E 3 E 4 E 5 E j E 7 E 8 E 9 E 1 E 6 Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,

29 BETA_X&Y[m] 3 3 BETA_X&Y[m] Optimized Multi-pass ER Optics DISP_X&Y[m] Drift Lac Acceleration/Deceleration M M 1 2 M3 M M 4 5 M6 M M 7 8 M9 1 M BETA_X BETA_Y DISP_X DISP_Y E 4 E 5 E j E 7 E 8 E 9 E 1 E 1 E 2 E 3 E 6 6 FODO M2 M3 M4 M5 M6 M M M M M1 b 1 b ds E L E m BETA_X BETA_Y DISP_X DISP_Y E 1 E 2 E 3 E 4 E 5 E j E 7 E 8 E 9 E 1 E 6 Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,

30 1 BETA_X&Y[m] 5-pass up + 5-pass down Optics 5 DISP_X&Y[m] -5 INJ - NL BETA_X BETA_Y DISP_X DISP_Y 85 MeV MeV Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24, 216 3

31 BETA_X&Y[m] 3 3 BETA_X&Y[m] 5-pass up + 5-pass down Optics 5 DISP_X&Y[m] -5 5 DISP_X&Y[m] -5 ARC1 - SL 835 MeV BETA_X BETA_Y DISP_X DISP_Y MeV ARC2 - NL 85 MeV BETA_X BETA_Y DISP_X DISP_Y MeV 2335 MeV Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,

32 6 BETA_X&Y[m] BETA_X&Y[m] 3 5-pass up + 5-pass down Optics 5 DISP_X&Y[m] -5 5 DISP_X&Y[m] -5 ARC3 - SL 2335 MeV BETA_X BETA_Y DISP_X DISP_Y MeV ARC4 - NL BETA_X BETA_Y DISP_X DISP_Y MeV 3835 MeV Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,

33 BETA_X&Y[m] 4 4 BETA_X&Y[m] 5-pass up + 5-pass down Optics 5 DISP_X&Y[m] -5 5 DISP_X&Y[m] -5 ARC9 - SL BETA_X BETA_Y DISP_X DISP_Y MeV 7585 MeV ARCA - NL Dl/2 BETA_X BETA_Y DISP_X DISP_Y MeV 6835 MeV Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,

34 BETA_X&Y[m] 6 3 BETA_X&Y[m] 5-pass up + 5-pass down Optics 5 DISP_X&Y[m] -5 5 DISP_X&Y[m] -5 ARC4 - NL 385 MeV BETA_X BETA_Y DISP_X DISP_Y MeV ARC3 - SL 2335 MeV BETA_X BETA_Y DISP_X DISP_Y MeV Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,

35 3 BETA_X&Y[m] BETA_X&Y[m] 3 5-pass up + 5-pass down Optics 5 DISP_X&Y[m] -5 5 DISP_X&Y[m] -5 ARC2 - NL BETA_X BETA_Y DISP_X DISP_Y MeV 835 MeV ARC1 - SL BETA_X BETA_Y DISP_X DISP_Y MeV 85 MeV Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,

36 RLA Topologies DE/2 Racetrack DE/2 2 DE/2 Dogbone DE Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,

37 Racetrack vs Dogbone RLA DE/2 1.5 DE DE/2 DE 3 DE Twice the acceleration efficiency traversg the lac both directions while acceleratg Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,

38 Dogbone vs Racetrack Arc-length 9 DE/2 9 DE/2 n = n(p 4 )R 2n = 2npR Net arc-length break even: if p/4 Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,

39 Racetrack vs Dogbone ERL Racetrack 3-pass RLA.5 GeV 1 GeV 3 GeV 5 GeV 1 GeV lac.5 GeV 2 GeV 4 GeV 6 GeV 1 GeV lac IP 6 GeV Dogbone 5.5-pass RLA 49 GeV 28 GeV 6 GeV.5 GeV 17 GeV 39 GeV 6 GeV 11 GeV lac.5 GeV IP 6 GeV 5 3 p / Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,

40 BETA_X&Y[m] DISP_X&Y[m] 15 5 BETA_X&Y[m] DISP_X&Y[m] 15 5 Multi-pass Lac Optics Bisected Lac half pass, 9-12 MeV quad gradient itial phase adv/cell 9 deg. scalg quads with energy 6 meter 9 deg. FODO cells 17 MV/m RF, 2 cell cavities BETA_X BETA_Y DISP_X DISP_Y pass, MeV mirror symmetric quads the lac quad gradient BETA_X BETA_Y DISP_X DISP_Y Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24, 216 4

41 BETA_X&Y[m] 3 Multi-pass Lac Optics - Acceleration 5 DISP_X&Y[m] Arc 1 Arc 2 Arc 3 Arc 4 Arc 5 BETA_X BETA_Y DISP_X DISP_Y GeV 1.2 GeV 1.8 GeV 2.4 GeV 3. GeV 3.6 GeV quad grad. length Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,

42 BETA_X&Y[m] 3 Multi-pass Lac Optics - Deceleration 5 DISP_X&Y[m] Arc 5 Arc 4 Arc 3 Arc 2 Arc 1 BETA_X BETA_Y DISP_X DISP_Y GeV 3. GeV 2.4 GeV 1.8 GeV 1.2 GeV.9 GeV quad grad. length Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,

43 Beam Breakup Instability (BBU) Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,

44 Beam Breakup Instability (BBU) Krafft, Bisognano, and Laubach, unpublished (1988) Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,

45 Beam Breakup Instability (BBU) Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,

46 Beam Breakup Instability (BBU) Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,

47 Nonlear Beam Optics Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,

48 Nonlear Beam Optics Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,

49 JLAB IR/UV FEL Parameter IR UV Energy (MeV) I ave (ma) Q bunch (pc) e N transverse/longitudal (mm-mrad/kev-psec) 8/75 5/5 s p/p, s l (fsec).4%, 16.4%, 1 I peak (A) 4 25 FEL repetition rate (MHz) (cavity fundamental ) h FEL 2.5%.8% DE full after FEL ~15% ~7% DC Gun Dump Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,

50 Longitudal Matchg Scenario High peak current (short bunch) at FEL bunch length compression at wiggler E usg quads and sextupoles to adjust compactions Small energy spread at dump energy compress while energy recoverg f E short RF wavelength/long bunch, large exhaust p/p (~1%) get slope, curvature, and torsion right E (quads, sextupoles, octupoles) f E E f f E f f Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24, 216 5

51 ERL for of Electron Ion Collider 6 GeV (e) x 7 TeV (p) (2 GeV per pass) TOTAL CIRCUMFERENCE ~ 8.9 km Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,

52 ERL for of Electron Ion Collider Arc6: Ds = l/2 6 GeV (e) x 7 TeV (p) (2 GeV per pass) TOTAL CIRCUMFERENCE ~ 8.9 km Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,

53 ERL for of Electron Ion Collider 6 GeV (e) x 7 TeV (p) (2 GeV per pass) TOTAL CIRCUMFERENCE ~ 8.9 km Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,

54 17 MeV-ERL at JAEA 17 MeV Loop first arc undulator 23 kv E-gun 2.5 MeV Injector return arc 5 MHz SCA (7.5 MV x 2) beam dump 5 MHz SCA (1 MV x 2) 2 m 2.5 MeV jector consists of 23 kev thermionic cathode gun, 83 MHz sub harmonic buncher, and two sgle-cell 5 MHz SCAs. 17 MeV loop consists of a merger chicane, two five-cell 5 MHz SCAs, a triplebend achromat arc, half-chicane, undulator, return-arc, and beam dump. Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,

55 berlpro Berl ERL Project 1 ma / low emittance technology demonstrator (coverg key aspects of a large scale ERL) merger dogleg lac module 3 x 7 cell srf cavities, 44 MeV beam dump 6.5 MeV, 1 ma 65 kw srf-gun 1.4 cell srf cavities MeV, sgle solenoid booster 3 x 2 cell srf cavities 4.5 MeV Lecture 12 - Beam Dynamics of ERLs 55

56 Electron Ion Collider erhic Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,

57 Overview of Projects and Facilities First idea: M. Tigner (1965) JLAB-FEL: Demo-FEL (1999) & FEL Upgrade (24) First energy recovery: Stanford SCA/FEL (1987) KEK cerl (214): recirc. & energy recovery Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,

58 ERL Worldwide Landscape red markers denote previous ERL demonstrations, green markers dicate current ERLs, and black markers represent future ERLs. CEBAF-ER 5-pass Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,

59 Summary and Outlook High energy (tens of GeV), high current (tens of ma) beams: (sub GW beam power) would require GW-class RF systems (klystrons) conventional lacs. Invokg Energy Recovery alleviates extreme RF power demand (reduced by factor of: 1 - h ERL ). Required RF power becomes nearly dependent of beam current. Energy Recoverg Lacs promise efficiencies of storage rgs, while matag beam quality of lacs: superior emittance and energy spread and short bunches (sub-pico sec.) The next generation of high energy, high current, recirculatg lear accelerators (RLAs) will rely on the energy recovery (ER) process to mitigate their extreme power demand. Wide range of applications: Light Sources/FELs, Colliders, Ion Coolers, Isotope production Maximizg number of passes is the key to a cost effective ERL scheme. Lecture 12 - Beam Dynamics of ERLs USPAS, Fort Colls, CO, June 13-24,