Funded by the European Union Compact Light progress

Funded by the European Union Compact. Light progress and status Gerardo D’Auria (Elettra- ST) on behalf of the Compact. Light Collaboration (XLS) 12 th International Workshop on Breakdown Science and High-Gradient Technology, HG 2019 Chamonix 10 -14 June 2019 www. Compact. Light. eu HG 2019 Chamonix 12 June 2019 1

Funded by the European Union Outline Ø Context • • The XLS Collaboration Aims & Motivations Ø Timeline & Deliverables Ø Facility design/Users requirements: • Essentials FEL parameters • Desiderables Machine layout Ø Ongoing activities HG 2019 Chamonix 12 June 2019 G. D’Auria 2

Funded by the European Union The Compact. Light Collaboration Compact. Light (XLS) is an initiative among several International Laboratories aimed at promoting the construction of the next generation FEL based photon sources with innovative accelerator technologies 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Organisation Name Elettra – Sincrotrone Trieste S. C. p. A. CERN - European Organization for Nuclear Research Science and Tech. Facility Council – Daresbury Lab. Shanghai Institute of Applied Physics Institute of Accelerating Systems and Applications Uppsala Universitet Melbourne University Australian Nuclear Science and Tecnology Org. Ankara Univ. Institute of Accel. Techn. Lancaster Univ. VDL Enabling Technology Group Eindhoven Technische Universiteit Eindhoven Istituto Nazionale di Fisica Nucleare Kyma S. r. l. Rome Univ. "La Sapienza" ENEA ALBA Lab. de Luz Sincrotron CNRS Centre Nat. de la Rech. Scient. Karlsruher Instritut für Technologie Paul Scherrer Institute CSIC Valencia Univ. Helsinki Univ. Institute of Physics ARCLN Amsterdam Strathclyde Univ. Country Italy Intern. UK China Greece Sweden Australia Turkey UK NL NL Italy Spain France Germany CH Spain Finland NL UK http: //Compact. Light. eu • Compact. Light is an EU Design Study (RIA) • Starting date 01 -01 -2018 • Duration 36 months • Total cost of the project 3. 5 M€ • EU contribution: 3 M€ • 24 participating organisations within 13 countries including CERN + 5 associated partners. • 7 Work Packages HG 2019 Chamonix 12 June 2019 G. D’Auria 3

Funded by the European Union Time plan, Milestones and Deliverables M D Kick-off Meeting Public WEB site I Midterm Rev. Meet. I Annual Meet. II Midterm Rev. Meet. Helsinki July 01 -04 User Meet. & Req. Rep HG 2019 Chamonix 12 June 2019 G. D’Auria 4

Next Meeting Funded by the European Union 2 nd Midterm Review Meeting Helsinki 1 -4 July 2019 A session will be dedicated to Industry to discuss the current Modulator & Klystron technology and expected developments in the next 3 -5 years ü ü ü CPI CANON THALES SCANDINOVA JEMA AMPEGON ? (not yet confirmed) HG 2019 Chamonix 12 June 2019 G. D’Auria 5

Funded by the European Union List of Deliverables 30 June 2019 31 Dec. 2019 HG 2019 Chamonix 12 June 2019 G. D’Auria 6

Funded by the European Union June 2019 Deliverables WP 3 INFN D 3. 1 Evaluation report of the optimum e-gun and injector solution for the XLS CDR. D 3. 2 A review report on the bunch compression techniques and phase space linearization WP 4 CERN D 4. 1 Computer code report for RF power unit design and cost optimization. WP 5 ENEA D 5. 1 A review report comparing the different technologies for the Compact. Light undulator. WP 6 UA-IAT D 6. 1 Review report on the most advanced computer codes for the facility design HG 2019 Chamonix 12 June 2019 G. D’Auria 7

Funded by the European Union Facility design Compact. Light Users’ Meeting (CERN 27 -28 November 2018) AIM: to collect, from the FEL Scientific Community, the requirements, in term of photon beam characteristics, for an ambitious future hard X-ray FEL Facility, in the medium and long-term perspectives. XLS Deliverable D 2. 1: FEL Science Requirements and Facility Design Prepared on 20 -12 -2018 by: Alan Mak, Peter Salén, Vitaliy Goryashko and Jim Clarke ESSENTIALS That should be provided by the CORE FACILITY as compact and upgradable as possible DESIDERABLES That could be provided by the CORE FACILITY parassitically or with an upgrade D. Dunning , N. Thompson HG 2019 Chamonix 12 June 2019 G. D’Auria 8

Funded by the European Union ESSENTIAL Users requirements Ø Photon energy range at the fundamental: 0. 25 – 16. 0 ke. V Ø Variable, selectable polarization Repetition rate 100 Hz (higher, very welcome!) 2 -colours operation with timing separation +/- 100 fs and colour separation 20% in SXR and 10% in HXR Wavelength tuning primarly by undulator scanning with several discrete beam energies Pulse duration 1 - 50 fs Even pulse spacing and <10 fs synchronisation between FEL pulse and external laser Competitive pulse energy Ø Ø Ø HG 2019 Chamonix 12 June 2019 G. D’Auria 9

Funded by the European Union FEL main Parameters Preliminary Parameters of the Compact. Light FEL *A repetition rate of 1000 Hz would be a unique and desirable feature of our design! We recognise that this is a very challenging target that we may have to reduce during the study. HG 2019 Chamonix 12 June 2019 G. D’Auria 10

Funded by the European Union FEL schematic layout To meet the FEL parameters & the ESSENTIAL Users requirements Ø A strong field undulator with short period and small gap to minimise the beam energy is required. Ø Choose an appropriate set of the undulator period in order to give a factor of two wavelength tuning at each beam energy (i. e. Dunning proposal: 6 discrete beam energy working points to cover the whole range 0. 25 – 16 ke. V). Ø The variable polarisation could be provided by using an “Afterburner” for the last gain lengths. Ø Use two photo-injectors to have a double electron bunch with each bunch on separate RF cycle, independent charge, separated in energy and a controlled delay between them, to have pulses separated in time and wavelength. D. Dunning , N. Thompson HG 2019 Chamonix 12 June 2019 G. D’Auria 11

Funded by the European Union XLS FEL layout CORE MACHINE SCHEMATIC LAYOUT FIXED POL. GUN ≤ 1 -2 Ge. V X-BAND FEL-1 AB-1 FEL-2 AB-2 ≤ 5. 5 Ge. V X-BAND TIMING CHICANE TWIN PI LASERS VAR POL. FIXED POL. VAR POL. BEAM SPLITTER – Low freq. RF + dipole OPERATING MODES 1. FEL-1/FEL-2 independent double pulses to one experiment HXR 100 Hz 2. FEL-1/FEL-2 independent single pulses to two experiments HXR 100 Hz 3. FEL-1/FEL-2 independent double pulses to one experiment SXR 1 k. Hz 4. FEL-1/FEL-2 independent single pulses to two experiments SXR 1 k. Hz D. Dunning , N. Thompson HG 2019 Chamonix 12 June 2019 G. D’Auria 12

Funded by the European Union Soft X-ray Undulator parameters Hard X-ray Both undulator lines have identical parameters, so K is tuneable to provide a factor of 2 wavelength tuning for both Soft X-ray and Hard X-ray λu≈13 mm Ku≈0. 85 -1. 85 Ø Soft X-ray Ebeam≈1. 0/1. 4/1. 95 Ge. V (~3 discrete working points @increased rep. rate, TBC) Ø Hard X-ray Ebeam≈2. 75/3. 9/5. 5 Ge. V (~3 discrete working points @100 Hz) D. Dunning HG 2019 Chamonix 12 June 2019 G. D’Auria 13

Funded by the European Union With DESIDERABLES User Requirements XLS FEL upgraded layout • Stability • Seeding at all wavelengths • Repetition rate 1 k. Hz • Simultaneous HXR/SXR operation • Peak brightness 1033 ph/s/mm mrad 2/0. 1%bw at 16 ke. V Operating modes: 1. FEL-1/FEL-2 independent double pulses to one experiment HXR 100 Hz 2. FEL-1/FEL-2 independent single pulses to two experiments HXR 100 Hz 3. FEL-1/FEL-2 independent double pulses to one experiment SXR 1 k. Hz 4. FEL-1/FEL-2 independent single pulses to two experiments SXR 1 k. Hz 5. FEL-1 SASE/SEEDED SXR 100 Hz + FEL-2 SASE/SELF SEEDED HXR 100 Hz D. Dunning , N. Thompson HG 2019 Chamonix 12 June 2019 G. D’Auria 14

Funded by the European Union Undulator performance evaluation CPMU Delta Hybrid SCU Saturation Power (mean over pulse) (GW) 9. 1 8. 9 7. 6 9. 8 Saturation Length (m) 24. 5 26. 5 29. 1 15. 6 Saturation Pulse Energy (µJ) 49 48 29 54 FWHM Bandwidth (10 -3) 0. 987 0. 975 0. 996 1. 16 Peak Brightness (1033 x #ph/s/mm 2/mrad 2/0. 1%bw) 2. 39 2. 37 1. 98 2. 18 Preliminary results of GENESIS time-dependent simulations J. Clarke, N. Thompson HG 2019 Chamonix 12 June 2019 G. D’Auria 15

Funded by the European Union Beam parameters Main Electron Beam Parameters Longitudinal phase space from 1 -D tracking at the exit of the linac for SXR FEL (left) and at the exit of the linac for HXR FEL (right) HG 2019 Chamonix 12 June 2019 S. Di Mitri G. D’Auria 16

Funded by the European Union FEL Doubler Septum Beam scraping with a double slits (continuus variable) Beam brightness after scraping is almost preserved! S. Di Mitri HG 2019 Chamonix 12 June 2019 G. D’Auria 17

Funded by the European Union C-Band Ultra-Fast GUN Design (prel. ) Þ The C-band injector is based on an ultra-high gradient C-band gun (1. 6 cells) operating at 240 MV/m cathode peak field Þ We proposed to adopt an ultra-fast gun (rf pulses <150 ns) keeping under control all quantities that drive the breakdown phenomena (Modified Poynting vector, surface electric field, etc. ) Þ The design of the overall system is based on commercially available components (klystrons, circulators, pulse compressors, ect…) Þ We have optimized the 2 D profile of the cells and the input coupler exploring different solutions. An input coupler working on the TM 020 mode on the full cell seems to be the best solution KLY P. C. X 2. 1 Parameter fres ≈ 80 MHz Q 0 14347 β 3 QL 3623 τF 201 ns Ecath [MV/m] 240 Esurf/Ecath (on the coupler) 0. 91 Hsurf [k. A/m] (on the coupler) 357 KA/m Tpulsed (square pulse) @ 100 ns @ 200 ns 12. 2°C 17. 3°C 4 =3 Circ. 5. 712 GHz 56. 4 Circ. 100 ns, 85 MW GUN 1 -1. 5 s, 40 MW M. Croia HG 2019 Chamonix 12 June 2019 G. D’Auria 18

Funded by the European Union X-band Accel. Struct. Design & Optim. 50 MW, 1. 5 µs • Baseline accelerating gradient: 65 MV/m • RF system and pulse compressor characteristics • Average iris radius: 3. 5 mm Trade-off between machine compactness and RF power requirements Beam dynamics requirements (BBU threshold) • Electromagnetic parametric study of the TW cell • Effective shunt impedance optimization by a 2 D scan of the total length and the iris tapering • Check of modified Poynting vector values @ nominal gradient • Design a realistic RF module including power distribution network • Finalize the electromagnetic (input and output couplers) and mechanical design A. Gallo HG 2019 Chamonix 12 June 2019 G. D’Auria 19

Funded by the European Union RF structure Preliminary Parameters Freq. of 2π/3 mode [GHz] Compact Light optimum Best effective shunt impedance Eu. SPARC optimum Eu. SPARC working point (optimization of RF power splitting) 11. 9942 Average iris radius <a> [mm] 3. 5 Total length of the TW structure Ls [m] 0. 9 RF pulse [µs] 1. 5 Average gradient <G> [MV/m] 65 Linac Energy gain Egain [Ge. V] 5. 5 Linac active length Lact [m] 84. 7 Unloaded SLED Q-factor Q 0 180. 000 External SLED Q-factor QE 21400 Iris radius a [mm] 4. 3 -2. 7 Group velocity vg [%] 4. 5 -1. 0 Effective shunt Imp. Rs [M /m] 389 Filling time tf [ns] 140 Input power per structure Pk_s [MW] 9. 8 Structures per module Nm (input power per module Pk_m [MW]) 4 (39) Total number of structures Ntot 100 Total number of klystrons Nk 25 A. Gallo HG 2019 Chamonix 12 June 2019 G. D’Auria 20

Funded by the European Union Towards higher rep rate operation Different scenarios under investigations: 1 st scenario (1 klystron x LINAC Module): RF pulse shortening 50 MW, 1. 5 µs, 100 Hz <Eacc> = 65 MV/m 50 MW, 140 ns, 220 Hz <Eacc> = 30 MV/m • Linac energy downgraded to ≈ 45% of the max value @ 220 Hz rep rate; • Not flexible: as soon as the SLED is removed the gradient is reduced by a factor ≈2. 2; • Max rep rate very much dependent on modulator dead time τtrans 2 nd scenario (1 klystron x LINAC Module): klystron peak power reduced 50 MW, 1. 5 µs, 100 Hz 1. 5 µs, 10 MW, 200 Hz 1. 5 µs, 5 MW, 250 Hz <Eacc> = 29 MV/m @ 200 Hz <Eacc> = 20. 5 MV/m @ 250 Hz • Linac energy downgraded to ≈ 30% of the max value @ 250 Hz rep rate; • Flexible: different compromises between rep rate and RF peak power explorable; • Klystron operated in a wide range of working points (realistic? ) 3 rd scenario (2 klystrons x LINAC Module): - high rep rate/reduced peak power klystrons - low rep rate/HP klystron CANON E 37113 klystron, 6 MW 1. 5 µs, 1 KHz + CPI VKX 8311 A • …………? ? ? <Eacc> = 65 MV/m @ 100 Hz <Eacc> = 23 MV/m @ 1 k. Hz More detailed studies needed! HG 2019 Chamonix 12 June 2019 A. Gallo G. D’Auria 21

Funded by the European Union Beam manipulation_36 GHz power sources Ka-band gyro-klystron design Voltage (k. V) 95 Current (A) 45 Velocity ratio 1. 3 Drive power (W) 200 Beam guide radius (mm) 2. 3 Magnetic field (T) 1. 33 Result Power (MW) Ø 36 GHz, 2. 0 MW gyro-klystron simulation results Ø 36 GHz, 3. 0 MW gyro-klystron simulation results 1. 9 Bandwidth 0. 3% Efficiency • MIG-type electron gun 44% Gain (d. B) • Three-cavity structure • TE 01 mode for input and intermediate cavity • TE 02 for output cavity 39 (max 42) Voltage (k. V) 150 Current (A) 45 Velocity ratio 1. 4 Drive power (W) 400 Beam guide radius (mm) 2. 3 Magnetic field (T) 1. 46 Result Power (MW) 3. 0 Bandwidth 0. 3% Efficiency Gain (d. B) 39 (max 42) • Similar configuration but 44% with a higher operating voltage A. Cross, L. Wang HG 2019 Chamonix 12 June 2019 G. D’Auria 22

Funded by the European Union Conclusions ü Project is running well and all the WPs are progressing according to the time schedule. ü Advanced and challenging FEL schemes have been proposed and are under investigation. ü A big effort to check the possibility to operate the SXR facility at high repetition rate needs to be addressed asap. ü With the contributions of the whole Collaboration, we are facing a very intense and stimulating period……. Thanks to all the XLS Partners! HG 2019 Chamonix 12 June 2019 G. D’Auria 23

Funded by the European Union Thank you! Compact. Light@elettra. eu www. Compact. Light. eu Compact. Light is funded by the European Union’s Horizon 2020 Research and Innovation program under Grant Agreement No. 777431. HG 2019 Chamonix 12 June 2019 24