John Power Argonne National Laboratory AAC 2016, August 1, 2016 Demonstration of Longitudinal Bunch Shaping using an EEX beamline at the Argonne Wakefield Accelerator John Power Argonne National Laboratory AAC 2016, August 1, 2016 Go to "View | Header and Footer" to add your organization, sponsor, meeting name here; then, click "Apply to All"

Longitudinal Bunch Shaping: The Final Frontier Precise Transverse Bunch Shaping Straightforward SIMPLE COMPLEX Gaussian Hollow Cathode Ring Pepper Pot Matrix Multileaf Collimator Arbitrary Profile Method Laser Profile 2/27

Longitudinal Bunch Shaping: The Final Frontier What makes longitudinal bunch shaping so difficult? femtoseconds 800 fs There is no Fast Gate Electron bunch has extremely short duration (femtoseconds - picoseconds) Direct manipulation of the longitudinal bunch shape is difficult Need indirect methods 3/27

Longitudinal Bunch Shaping: The Final Frontier Limited Longitudinal Bunch Shaping Difficult, but recent progress (warning: not a comprehensive list!) SIMPLE COMPLEX Gaussian Trains Various (Most Active) *Laser Comb (SPARC) M. Boscolo 2007 *a-BBO (ANL) M. Conde (PAC12) *Wakefield + Chicane (Euclid/BNL) S. Antipov PRL 111, 134802 (2013) *mask+EEX (FNAL/NIU) Y. –E Sun, PRL 105, 234801 (2010) *R.J. England (UCLA) PRL 100, 214802 (2008) *P. Muggli (UCLA/BNL) PRL 101, 054801 (2008) *L. Emery (NIU) IPAC14 Triangle Arbitrary ???? a-BBO Pulse Stacking Flat *J.G. Power (ANL) AAC’08 *D. Edstrom (FNAL) IPAC2015 Profile Method Laser Profile 4/27

Longitudinal Bunch Shaping: The Final Frontier Precise Longitudinal Bunch Shaping Emittance Exchange based method BLACK BOX Arbitrary shaping All transverse shaping methods  longitudinal bunch shaping M. Cornacchia and P. Emma, Phys. Rev. ST Accel. Beams 5, (2002) P. Piot et al., Phys.Rev.ST Accel. Beams 14 (2011) *All schemes have practical limits. We are exploring these limits 5/27

APPLICATIONS & MOTIVATION 6/27

Motivation: wakefield acceleration and transformer ratio Dielectric Drive bunch Witness bunch 𝑊 + 𝑊 − 𝐑= 𝑊 + 𝑊 − = Maximum field behind drive bunch Maximum field inside drive bunch R<2 for symmetric bunches (Fundamental theorem of Wakefield) Assume 𝑁=𝑍/𝜆=2 12 6 2 4 9 7/27

Other applications… C. Mitchell, PRSTAB 16, 060703 CSR suppression Y. –E Sun, PRL 105, 234801 Train generation Zholents, FEL2014 Energy spread control G. Ha, IPAC2015 Longitudinal diagnostics [bottom right: resolution limited by correlation] & [bottom left] “beam loading in CWFA” 8/27 Go to "View | Header and Footer" to add your organization, sponsor, meeting name here; then, click "Apply to All"

Understanding the Eex BEAMLINE 9/27

2 building blocks  dogleg + deflecting cavity EEX beamline difficult to understand Exchange process complex motion of the beam inside the EEX beamline 2 building blocks  dogleg + deflecting cavity 𝑥 1 = 𝑥 0 +𝐿 𝑥 0 ′ +𝜂 𝛿 0 𝑀 𝑑𝑜𝑔𝑙𝑒𝑔 = 1 𝐿 0 h 0 1 0 0 0 h 1 x 0 0 0 1 𝑥 1 ′ = 𝑥 0 ′ 𝑧 1 =𝜂 𝑥 0 ′ + 𝑧 0 +𝜉 𝛿 0 Dogleg does not affect momentum 𝛿 1 = 𝛿 0 Complementary blocks 𝑀 𝑇𝐷𝐶 = 1 0 0 0 0 1 𝜅 0 0 0 1 0 𝜅 0 0 1 𝑥 1 = 𝑥 0 𝑥 1 ′ = 𝑥 0 ′ +𝜅 𝑧 0 TDC does not affect position 𝑧 1 = 𝑧 0 𝛿 1 = 𝜅 𝑥 0 +𝛿 0 Complementary beamline elements 10/27

Emittance exchange with the EEX beamline Transport Matrix Position → Momentum 𝑥 𝑓 𝑥 𝑓 ′ 𝑧 𝑓 𝛿 𝑓 = 0 0 𝜅𝐿 𝜂+𝜅𝜉𝐿 0 0 𝜅 𝜅𝜉 𝜅𝜉 𝜂+𝜅𝜉𝐿 0 0 𝜅 𝜅𝐿 0 0 𝑥 𝑖 𝑥 𝑖 ′ 𝑧 𝑖 𝛿 𝑖 Ez z x By Final longitudinal properties are only determined by initial horizontal properties 2 particles (e.g. momentum exchange) 0 0 0 𝛿 0 0 0 0 0 Δ𝑥=𝜂Δ𝛿 Δ𝛿=Δ𝛿+𝜅𝜂Δ𝛿 Δ𝛿=0 1+𝜅𝜂=0 Momentum → Position X instead of horizontal is simpler Double dog-leg emittance exchanger z x By z x z x 11/27 Go to "View | Header and Footer" to add your organization, sponsor, meeting name here; then, click "Apply to All"

Longitudinal Bunch Shaping with the EEX beamline AFTER MASK AFTER EEX 12/27

LONGITUDINAL BUNCH SHAPING EXPERIMENT AT THE AWA FACILITY 13/27

EEX based Bunch Shaping Experiments at the AWA Facility *Ph. D. project of Gwanghui Ha (POSTECH and ANL) Collaboration: Argonne National Laboratory, HEP: M. Conde, W.Gai, G.Ha, J.G.Power Argonne National Laboratory, APS: Y. Sun, R.Lindberg, A.Zholents Northern Illinois University: P.Piot Los Alamos National Laboratory: D. Shchegolkov, E. Simakov Euclid Techlabs LLC: C.Jing, A.Kanareykin, P.Schoessow 14/27

Double dogleg EEX beam line at AWA Argonne Wakefield Accelerator Double dogleg EEX ~68 MeV Chirp control Transverse manipulation Experimental area ~8 MeV Up to 100 nC 5 nC / 48 MeV Quadrupole Dipole magnet Transverse Deflecting cavity Mask Beam line parameter Value Unit Bending angle 20 deg Dipole-to-Dipole 2.0 m Dipole-to-TDC 0.5 Power to TDC 1.2 MW 15/27

Demonstration of property exchange EXPERIMENT Pending publication z x Scan X instead of horizontal is simpler 16/27 Go to "View | Header and Footer" to add your organization, sponsor, meeting name here; then, click "Apply to All"

Demonstration of longitudinal bunch shaping z x y Demonstration of longitudinal bunch shaping EXPERIMENT Pending publication Take initial x-horizontal profile 5 nC / 48 MeV z x y In preparation for journal 17/27

Perturbation on ideal exchange SIMULATION 𝑧 𝑓 =𝜅𝜉 𝑥 𝑜 + 𝜂+𝜅𝜉 𝐿+ 𝐿 𝐷 + 𝐿 𝑐 4 𝑥 0 ′ + 𝑇 𝑛𝑚 𝑋 𝑛 𝑋 𝑚 + 𝜉Δ𝛿 Second order terms Collective effects Linear terms x-x′ z-δ Perturbation on the position Perturbation patterns EEX Overlap of position 𝑥 0 ′ 𝑥 0 =− 2 T 11 𝑇 12 Minimize slope 𝑇 11 𝑥 0 2 + 𝑇 12 𝑥 0 𝑥 0 ′ + 𝑇 22 𝑥 0 ′ 2 In preparation for journal 18/27

Perturbation control by incoming slope manipulation EXPERIMENT X - distribution Z - distribution Linac phase control → thick-lens effect and collective effects -10 deg -15 deg -30 deg -40 deg Pending publication Horizontal control → few critical second order terms 0.03 0.17 0.47 0.60 19/27

APPLICATIONS AT THE AWA FACILITY 20/27

Future Experiment: High Transformer Ratio SIMULATION Rectangular Dielectric Wakefield Structure 800 mm Metal 18 mm Alumina (130 mm) 3mm (Vacuum gap) Calculated with Euclid Wake Code and verified with CST microwave studio. Transverse Profile at Entrance Take Advantage of the AWA double dog-leg EEX beam’s natural shape Flat beam profile (horizontal >> vertical) Bunch Length < 10 mm Note: A double EEX beamline can easily accommodate a cylindrical wakefield structure

Future Experiment: High Transformer Ratio SIMULATION Rectangular Dielectric Wakefield Structure Mask Beam transport through structure 12 nC 3.9 nC Beam envelope Longitudinal Bunch Shape & Transformer ratio Explain animation Euclid Techlabs LLC: Q. Gao, C.Jing, A.Kanareykin. 22/27 Go to "View | Header and Footer" to add your organization, sponsor, meeting name here; then, click "Apply to All"

LONGITUDINAL BUNCH SHAPING FUTURE DIRECTIONS IN EEX-BASED LONGITUDINAL BUNCH SHAPING 23/27

Double EEX experiment* *A.A. Zholents & M.S. Zolotrev (APS LS-327) New type of bunch compressor Tunable compression using quad No chirp requirement. No dechirper Control all longitudinal property at the same time Shaping with preserved transverse emittance 2. Transverse manipulation Already installed EEX-2 EEX-1 3. Bring the manipulated transverse properties back to longitudinal 1. Bring the longitudinal properties to the transverse space 24/27

Double EEX experiment Experimental Area ~1 meter Preliminary Layout 836.497 in[21247.02 mm] 779.132 in[19789.95 mm] 693.458 in[17613.83 mm] 574.921 in[14602.99 mm] 523.12 in[13277.25 mm] 484.12 in[12296.65 mm] 454.278 in[11538.66 mm] 333.752 in[8477.30 mm] 246.789 in[6268.44 mm] 216.375 in[5495.93 mm] 182.695 in[4640.45 mm] 94.371 in [2397.02 mm] Center of Valve is ZERO Overall Length 870.431 in 605.335 in[15375.51 mm] 541.241 in[13747.52 mm] Experimental Area ~1 meter All Quads Shown 25 cm center/center Dimensions Unchanged Trims 15 cm center/center 25/27

Preliminary GPT Simulations – shaping capability longitudinal phase space pz (MeV/c) z (mm) After EEX-2 Rectangle EEX-1 After Mask Horizontal x-profile EEX-2 Transverse profile After Mask After EEX-2 z (mm) Arbt. witness drive 0.6mm 1.5 mm Longitudinal z-profile Before EEX-1 Transverse Profile 26/27

Summary Longitudinal Bunch Shaping Demonstration Experiment Future: Method: was done with an EEX beamline Applications: collinear wakefield acceleration, THz radiation, CSR or energy spread control etc. Demonstration Experiment Double dogleg EEX beamline was installed at Argonne Wakefield Accelerator. Several different longitudinal bunch shapes were successfully generated Perturbations were controlled with the incoming slope of phase ellipse. Future: A high transformer ratio experiment using the EEX beamline is planned A double-EEX beamline will be installed at the AWA facility. 27/27

Acknowledgement G. Ha, M. H. Cho, W. Namkung (Pohang University of Science and Technology) E. Wiesniewski, W. Liu, M. Conde, D. S. Doran, C. Whiteford, W. Gai (Argonne National Laboratory, AWA) K. –J. Kim, A. Zholents, Y. –E Sun (Argonne National Laboratory, APS) C. Jing, S. Antipov (Euclid TechLabs) P. Piot (Northern Illinois University/Fermilab) Q. Gao (Tsinghua University) 28/27

Thank you for your attention 29/27

Backup slides concepts 30/27

Multipole pre-shaping No sextupole Sextupole, +5 A Sextupole, -5 A 31/27

A concept of a multi-user FEL facility Based on: ~50 m ~200 m SRF: 2.5 GeV ~1 MHz E-gun Undulators ~300 m Spreader experimental end stations High repetition rate SRF linac (NGLS-like) Collinear Wakefield Accelerator (CWA) Low E spreader Up to 100 MV/m CWA imbedded in quadrupole wiggler Tunable E ~ a few GeV Tunable Ipk> 1KA Rep. rate ~50 kHz/FEL Compact Inexpensive Flexible 32/27

Motivation: Why do we need collinear DWFA? Cu Q Dielectric 2a 2b High gradient High repetition Cheap and simple Why do we need high TR? 400 m Q 4 GeV 𝑊 𝑧 + =200 𝑀𝑉/𝑚/𝑛𝐶 40 m 𝑊 𝑧 − =100 𝑀𝑉/𝑚/𝑛𝐶 8 GeV 1 nC R=2 100 m Q 1 GeV 𝑊 𝑧 + =50 𝑀𝑉/𝑚/𝑛𝐶 40 m 𝑊 𝑧 − =6.25 𝑀𝑉/𝑚/𝑛𝐶 8 GeV 4 nC R=8 33/27

Backup – AWA EEX beam line 34/27

Backup – mask and YAG 35/27

High resolution longitudinal diagnostics Measurement using TDC or spectrometer has clear limit (for the bunch length ~ 10 fs) Since the limit is originated from correlation, exchange method can overcome this limitation. 36/27

Tunable THz or X-ray generation using trans. modulation + EEX Transverse modulation generated from alternating magnetic field or structure+laser can be converted to longitudinal train with EEX Tunable train can be used to generate tunable THz or even tunable X-ray y x 3.2 mm -> 0.3 mm 37/27