EUROPEAN PLASMA RESEARCH ACCELERATOR WITH EXCELLENCE IN APPLICATIONS

EUROPEAN PLASMA RESEARCH ACCELERATOR WITH EXCELLENCE IN APPLICATIONS Diagnostics conceptual design for a Eupraxia-like (lite) machine Alessandro Cianchi University of Rome Tor Vergata and INFN With a lot of contributions from Enrica Chiadroni, Nicolas Delerue, Claire Simon, David Alesini, Alessandro Gallo, Massimo Ferrario, James Rosenzweig This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 653782.

Outline • • Horizon 2020 Introducing Eusparc Diagnostics state of the art Diagnostics under development Possible conceptual design of diagnostics for a whole machine A. Cianchi 1 st Eupraxia Collaboration week – Hamburg 19 th – 23 rd June 2017 2

EUSPARC Horizon 2020 • FEL user facility (1 Ge. V – 3 nm) • Advanced Accelerator Test facility (LC) 3 m 35 m 55 m 40 m 27 m 130 m • 500 Me. V by RF Linac + 500 Me. V by Plasma • 1 Ge. V by RF Linac only A. Cianchi 1 st Eupraxia Collaboration week – Hamburg 19 th – 23 rd June 2017

X band (EU) Accelerator Horizon 2020 10. 5 m 62. 5 m RF & power supplies 8 m • • 11. 3 m 8. 8 m Injector Linac 1 Injector: – Gun+solenoid – 3 x 3 m s-band sectons Linac 1: – 8 x 0. 5 m x-band sections – Matching Quads 55 m 12 m 13. 9 m Compressor • 7. 5 m Linac 2 Compressor: – 2. 19° deflection • Linac 2: – 14 x 0. 5 m x-band sections – Matching Quads • Plasma: – PMQ matching – 0. 6 m capillary A. Cianchi 1 st Eupraxia Collaboration week – Hamburg 19 th – 23 rd June 2017 5 m Plasma

Parameters Horizon 2020 PWFA 2 Eusparc Eu. PRAXIA FEL-CDR FEL-SASE 1 Xband FEL Units 1 Ge. V -SASE 1 Witness bunch 1 Driver Ge. V Linac parameters 1 – (maybe 2) 1 No. Bunches ps (maybe 83) 1 Bunch separation Hz 10 – 100 10 10 Rep. rate 0. 15 Injector energy Ge. V > 70 Xband Acc. Gradient MV/m 1. – (1. 5) 0. 5 Exit linac energy Ge. V Electron parameters after acceleration % <1. <1 <1 < 1 Rms Energy Spread k. A 2 3 1. 5 1. 8 Peak current p. C 100 30 10 200 Bunch charge 15 (50) 3 (10) 2 (7) 34 (112) Bunch length rms µm (fs) µm < 1. <1. 5 <1 < 2 Rms norm. emittance Electron parameters at undulator start 1 1 1 Electron energy Ge. V µm 0. 75 Slice Length p. C 4. 5 7. 5 3. 7 Slice Charge % 0. 1 Slice Energy Spread µm 0. 5 1 0. 5 Slice norm. emittance A. Cianchi 1 st Eupraxia Collaboration week – Hamburg 19 th – 23 rd June 2017 5

General statements Horizon 2020 • Conventional accelerators diagnostics is not a big challenge • But an X-band accelerator is very compact, small, and also the diagnostics must be compact as well. • There are several challenges for the diagnostics in the PWFA regime: – The bunch length is very small, down to few mm – The bunch size is also very small, down to few mm – SINGLE SHOT! • For the conventional accelerator there are conventional solutions • Diagnostics after the plasma acceleration will be several affected by – Capture Optics – Driver contamination – Lack of single shot emittance diagnostics A. Cianchi 1 st Eupraxia Collaboration week – Hamburg 19 th – 23 rd June 2017

View Screens • View screens Horizon 2020 – Fundamental to measure the envelope and properly match the beam in the different accelerator sections – Compact design is required A. Cianchi 1 st Eupraxia Collaboration week – Hamburg 19 th – 23 rd June 2017

COTR problem Horizon 2020 – With high current and some dispersive elements, microbunching can appear – COTR is fatal in the beam size measurement – YAG: CE or similar with Scheimpflug optics – But only OTR is available when resolution better than 5 um is needed (problem with coherent radiation!) Ischebeck, Rasmus, et al. "Transverse profile imager for ultrabright electron beams. " Physical Review Special Topics-Accelerators and Beams 18. 8 (2015): 082802. A. Cianchi 1 st Eupraxia Collaboration week – Hamburg 19 th – 23 rd June 2017 8

Longitudinal diagnostics Bunch length rms µm (fs) 15 (50) 3 (10) 2 (7) Horizon 2020 34 (112) • X-band RFD • EOS (used also with time of arrival monitor) • Coherent radiation spectrum (hopefully single shot) • Compression monitor (Pyrodetector or Golay cell)

SLAC solution Horizon 2020 Distance between deflector and screen 32 m! • Dolgashev, Valery A. , et al. "Design and application of multimegawatt Xband deflectors for femtosecond electron beam diagnostics. " Physical Review Special Topics-Accelerators and Beams 17. 10 (2014): 102801. A. Cianchi 1 st Eupraxia Collaboration week – Hamburg 19 th – 23 rd June 2017

Plasma deflector? Attosecond resolution Horizon 2020 • Very compact, mm size • It needs to be proved • Dornmair, Irene, et al. "Plasma-driven ultrashort bunch diagnostics. " Physical Review Accelerators and Beams 19. 6 (2016): 062801. A. Cianchi 1 st Eupraxia Collaboration week – Hamburg 19 th – 23 rd June 2017

Single shot CTR measurements Horizon 2020 Pyro-electric line detector 30 channels @ room temperature no window, works in vacuum fast read out sensitivity KRS-5 (thallium bromoiodide) prism based spectrometer developed Also double prism (Zn. Se), S. Wunderlich et al. , Proceedings of IBIC 2014 • S. Wesch, B. Schmidt, C. Behrens, H. Delsim. Hashemi, P. Schmuser, Nuclear Instruments and Methods in Physics Research A 665 (2011) 40– 47 • T. J. Maxwell et al. Physical review letters 111. 18 (2013) A. Cianchi 1 st Eupraxia Collaboration week – Hamburg 19 th – 23 rd June 2017

Smith Purcell Horizon 2020 • Ongoing experiment to measure the bunch length in single shot using the natural dispersion of the grid H. L. Andrews et al. “Longitudinal profile monitors using Coherent Smith–Purcell radiation. ” NIM A 740 (2014) pp. 212– 215. http: //dx. doi. org/10. 1016/j. nima. 2013. 11. 090 A. Cianchi 1 st Eupraxia Collaboration week – Hamburg 19 th – 23 rd June 2017 13

Recent SP results at the CLIO FEL Spectrum • • • Measurements at the CLIO FEL (30 -45 Me. V) Buncher phase scanned around working point. Spectrum measured by 11 pyro detectors. From the spectrum we compute the form factor and then the beam profile. Dependence of the profile on the phase clearly observed. Upgrade of the experiment in progress to improve resolution. Horizon 2020

Longitudinal diagnostics Horizon 2020 • X-band RFD (limited to few fs) • EOS (Electro Optical Sampling used also with time of arrival monitor), limited to about 4050 fs • Coherent radiation spectrum (hopefully single shot, some developed, other in progress): not limited in principle • More to come: ? ? – TDP (Transverse Deflecting Plasma) limited to hundreds of as

Charge and trajectory Horizon 2020 m m 0 0 1 • PSI cavity BPM, frequency 3. 2844 GHz A. Cianchi 1 st Eupraxia Collaboration week – Hamburg 19 th – 23 rd June 2017 16 mm • Bergoz Turbo- ICT (down to 50 f. C, up to 300 p. C) for the charge • Stripline BPM or button BPM for S band linac • Cavity BPM (likely C or X band) for the rest of the machine

X band as BPM • • • Horizon 2020 Use of the dipole mode to estimate the beam position Needs to be calibrate vs conventional BPM Developed at NLC Used in CALIFES@CERN Used also in Desy but in off course with L band superconductive cavity • C. Adolphsen et al. , Wakefield and Beam Centering Measurements of a Damped and Detuned X-Band Accelerator Structure, SLAC–PUB– 8174 A. Cianchi 1 st Eupraxia Collaboration week – Hamburg 19 th – 23 rd June 2017

Special diagnostics Horizon 2020 • One Shot Emittance – In developing at SPARC_LAB – Based on OTR – Proved the principle not the measure itself • Betatron radiation – Also developed at SPARC_LAB – First single shot emittance measurement of the beam inside the bubble – Include also the correlation term A. Cianchi 1 st Eupraxia Collaboration week – Hamburg 19 th – 23 rd June 2017

Betatron radiation Horizon 2020 A. Rousse et al. “Production of a ke. V X-Ray Beam from Synchrotron Radiation in Relativistic Laser-Plasma Interaction”, PRL 93, 135005 (2004) Picture from F Albert et al Plasma Phys. Control. Fusion 56 (2014) 084015 G. R. Plateau and al. , Low. Emittance Electron Bunches from a Laser-Plasma Accelerator Measured using Single-Shot XRay Spectroscopy, PRL 109, 064802 (2012) A. Cianchi 1 st Eupraxia Collaboration week – Hamburg 19 th – 23 rd June 2017

s s’ g Dg at the same time • Horizon 2020 S. Kneip and al. , PRST-AB 15, 021302 (2012) Source size by Fresnel diffraction Energy, energy spread and divergence behind the dipole A. Cianchi 1 st Eupraxia Collaboration week – Hamburg 19 th – 23 rd June 2017

Finally the correlation term Horizon 2020 • Measurement at the same time of the betatron radiation spectrum and electron spectrum A. Curcio et al, “Trace-space reconstruction of low-emittance electron beams through betatron radiation in laser-plasma accelerators”, PRAB 20, 012801 (2017) A. Cianchi 1 st Eupraxia Collaboration week – Hamburg 19 th – 23 rd June 2017 21

Transition radiation Electron beam Metallic screen Beam splitter Beam imaging system angular distribution A. Cianchi 1 st Eupraxia Collaboration week – Hamburg 19 th – 23 rd June 2017 Horizon 2020

Angular Resolution vs Energy A. Cianchi 1 st Eupraxia Collaboration week – Hamburg 19 th – 23 rd June 2017 Horizon 2020

Electron beam Layout Metallic screen Beam splitter Beam imaging system + High. QE CCD Microlens array Imaging of the microlens focal plane Intensified camera, angular distribution A. Cianchi 1 st Eupraxia Collaboration week – Hamburg 19 th – 23 rd June 2017 Horizon 2020

2 D Horizon 2020

Machine layout • • D 1 Horizon 2020 D 1 GUN D 2 S-Band X-Band up to BC 1 D 3 from BC 1 to plasma accelerator D 4 Plasma accelerator D 2 D 3 D 4

D 1 GUN Vacuum valve BPM Horizon 2020 Toroid Vacuum valve Correctors Gun Solenoid QE Thermal Emittance Energy Laser spot center on cathode Invariant envelope first screen Charge Trajectory Correctors Flag BPM

D 2 Linac before BC 1 S Band • • • RFD Pumping/Diagnostics Dipole Quadrupole X band SNOB (Scree. N c. Orrector and Bpm) system Envelope Emittance Bunch length (via EOS/CDR/RFD) Longitudinal phase space Compression monitor Horizon 2020

D 3 from bunch compressor to Plasma • • • Envelope Trajectory Emittance Bunch length (via CDR) Compression monitor Horizon 2020

D 4 Plasma accelerator RFD Dipole Pumping/Diagnostics Plasma accelerator Toroid Quadrupole • • • Emittance (via quadscan) Betatron radiation One shoot emittance Bunch length (via CDR/RFD) Trajectory Charge Horizon 2020