Strathclyde programme: beam and plasma diagnostic

1. Strathclyde programme:beam and plasma diagnostic Prof. Dino Jaroszynski and Silvia Cipiccia University of Strathclyde

2. Outline of talk Plasma characterization with THz-TDS Beam diagnostic: pulselengthmeasurements THz-TDS/CTR Electron energy measurements Conclusions and future work

3. Plasma characterization • Plasma for AWAKE: • Li or Rbvapour, density ≈ 1015cm-3 • Requirements: • Density uniformity <0.1% • Temperature uniformity • Diagnostic: EO-TDS to directly determine the plasma density and temperature in a single shot Small and large spatial scale

4. Plasma characterization • The plasma complex dielectric constant dielectric properties (for non-magnetised plasma) • wpis the plasma frequency, n is the plasma collisional frequency, which depends on the temperature and density. Attenuation constant Propagation constant Measuring absorption and phase delay (DF = L [w/c-k] ), plasma density and collisional frequency can be deduced

5. Plasma characterization • Experimental results @ Strathclyde: • 15 cm long, 2 cm diameter He filled tube (24 mbar) • Plasma formed with 1 kHz, 6 kV, 50 ns rise time electrical discharge (1011-1015 cm-3) • Ti:sapphire laser (1 mJ, 800 nm, 80 fs) to initiate THz emission from GaAs emitter • 1 mm thick <110> ZnTe crystal to sample the THz pulse • Time range: >30 ps (sampling window) • From the time resolve E(t)E(w) • Reference signal E0(w): THz pulse preceding the discharge Jamison,…and Jaroszynski, J. Appl. Phys. 93, 4334, 2003

6. Plasma characterization Experimental at Strathclyde: setup E(t) Phase shift: Field amplitude Jamison,…and Jaroszynski, J. Appl. Phys. 93, 4334, 2003

7. Plasma characterization • By simultaneously comparing the phase delays and the transmission cut-off with a reference phase delay we expect to determine the plasma density to within 0.1%. • Spatial distributionspatially resolved phase measurement. • Develop plasma media that are suitable for the EO diagnostic development (prototype developed at Strathclyde) • Improve stability of kHz Ti:sapphire laser to make it suitable for 0.1% plasma density measurements • Use diagnostic system to measure plasma density and determine density to within 0.1% and determine the spatial resolution. • Test EO TDS diagnostic system using the laser plasma wakefield accelerator at Strathclyde to determine temporal resolution

8. Beamdiagnostic • As for plasma: measurement based on THz EO-TDS • Plasma density: direct spectroscopic method • Electronbunch properties: transverse Coulomb field indirectly determined from induced electro-optic phase delays  • In AWAKE project: • p+: 450 GeV, 12 cm • e-: 5-20 MeV, 300fs-3 ps (0.165-1 mm)bunching sub-ps length (Konstantin presentation yesterday) *Jamison,…, Jarsozinsky, Opt. Lett. 31, 2006

9. Beamdiagnostic • Basic scheme: Spectral decoding Temporal decoding

10. Beamdiagnostic Spectral decoding • measure probe intensity I() • known (initial) (t) • infer I(t) • simple setup • Temporal resolution: • bandwidth of the laser: • e--probe distance: • Spectrometer resolution: FELIX: 46 MeV, 200 pC Temporal resolution: 400 fs 1.7ps FWHM Not suitable for ultra short electron bunches (i.e. <500 fsFWHM) Wilke et al. Phys. Rev. Lett. 88 124801 (2002).

11. Beamdiagnostic Temporal decoding: • More complex setup • Higher time-resolution sub 50 fs • No frequency mixing • Time resolution: independent of the chirped pulse duration FELIX: e-, 50 MeV, 1.5 mm Berden at al. PRL 11, (2004) Jamison,…, Jaroszynski, Opt. Lett. 18 (2003)

12. Beamdiagnostic • Thistechniquecould be used to measurealso the protonbunching • Possibleissues: • Placing crystal close to the beam before bending e- beam: large proton beam (up to cm size from Konstantin simulations) can hit the crystal • After bending before electron spectrometer: bunch length may not be preserved

13. Beamdiagnostic Synchronization: Time jitter of the order of the bunch length Berden at al. PRL 11, (2004)

14. Beamdiagnostic CTR: shorter bunch length e- beam thin metal foil 2 fs bunch measured at 1 m from source Peak current several kiloAmperes THz CTR: Coherent Transition Radiation Coherent transition radiation spectrum gives bunch length

15. Electron energy measurements • Designed by Allan Gillespie / Allan MacLeod • (ALPHA-X) • Built by Sigmaphi (France) • Dual function device • High resolution chamber • Resolution – design ~ 0.1% • Electron energy up to 105 MeV (Bmax = 1.65 T) • High energy chamber • Uses upstream quadrupoles to aid focusing • Energy resolution ~0.2 – 10% (energy dependent) • Electron energy up to ~ 660 MeV (Bmax = 1.65 T) • Can be scaled to higher energy and higher resolution

16. Electron energy measurements • Other possibility: • Indirect measurement using undulator radiation Ce:YAG crystal 300  10  1 mm Wiggins,.., Jaroszynski, Plasma Phys. Control. Fusion 52 2010

17. Conclusions • EO TDS methods possibility for plasma and beam characterization • Improve stability of kHz Ti:sapphire laser to make it suitable for 0.1% plasma density measurements • Use diagnostic system to measure plasma density and determine density to within 0.1% and determine the spatial resolution. • Test EO TDS diagnostic system using the laser plasma wakefield accelerator at Strathclyde to determine temporal resolution (well set up to do this – most equipment exists) • Develop numerical model of diagnostic system to compare with experiments

18. Conclusions • Theoretical of beam propagation of the emitted CTR • e- and p+beam properties evolve in the beam lines. • Numerical tools are available at Strathclyde to develop a model of the EO-TDS diagnostic system (a PhD student, from a Centre for Doctoral Training at Strathclyde, will be dedicated to the project). • Strathclyde will collaborate with Daresburyteams and other teams on electron beam and plasma diagnostics • Theoretical studies of plasma wakefield accelerator using reduced and PIC codes

19. ALPHA-X project Strathclyde (students and staff): Team: Dino Jaroszynski (Director) , Salima Abu-Azoum, Maria-PiaAnania, ConstantinAniculaesei, Rodolfo Bonifacio, Enrico Brunetti, SijiaChen, Silvia Cipiccia, David Clark, Bernhard Ersfeld, Paul Farrell, John Farmer, David Grant, Peter Grant, RanaulIslam, YevgenKravets, PanosLepipas, Tom McCanny, Grace Manahan, Martin Mitchell, Adam Noble, Guarav Raj, David Reboredo Gil, Anna Subiel, XueYang, Gregory Vieux, Gregor Welsh and Mark Wiggins Collaborators:Marie Boyd, Annette Sorensen, Gordon Rob, Brian McNeil, Ken Ledingham and Paul McKenna ALPHA-X: Current and past collaborators: Lancaster U., Cockcroft Institute / STFC - ASTeC, STFC – RAL CLF, U. St. Andrews, U. Dundee, U. Abertay-Dundee, U. Glasgow, Imperial College, IST Lisbon, U. Paris-Sud - LPGP, Pulsar Physics, UTA, CAS Beijing, U. Tsinghua, Shanghai Jiao Tong U., Beijing, Capital Normal U. Beijing, APRI, GIST Korea, UNIST Korea, LBNL, FSU Jena, U. Stellenbosch, U. Oxford, LAL, PSI, U. Twente, TUE, U. Bochum, IU Simon Cancer Center, Indianapolis, MGS Research, Inc., Madison, Royal Marsden, .... Support: University of Strathclyde, EPSRC, CSO, EU Laserlab, STFC consortium

20. Preliminary Participating Speakers : Bill Brocklesby, Christopher Barty, Allen Caldwell, Antonino Di Piazza, Toshikazu Ebisuzaki, Alexander Fedotov, Dieter Habs, Ryoichi Hajima, Kensuke Homma, Dino Jaroszynski, John Kirk, Alexander Litvak, Matthias Marklund, Edward Moses, Gerard Mourou, Kazuhisa Nakajima, Alexander Pukhov, HartmutRuhl, Igor Sokolov, Simon Suckewer, Sydney Gales, Toshiki Tajima, Robin Tucker, Xueqing Yan, Nicolae-Victor Zamfir Fields to be covered :Fundamental : Exa-Zettawatt Lasers and High Average ICAN Lasers- Beyond the Standard Model - Vacuum Structure - Dark Matter/Energy - High Energy AstrophysicsApplications : Medical - Accelerator Driven Systems - Imaging Venue :University of Strathclyde, Glasgow, Scotland, United KingdomNovember 13 and 14 : Thistle, GlasgowNovember 15 : Court Senate, University of Strathclyde, Glasgow

21. Thank you