SCAPA Scottish Universities Physics Alliance AWAKE Oct Strathclyde programme: beam and plasma diagnostic Prof. Dino Jaroszynski and Silvia Cipiccia University of Strathclyde

SCAPA Scottish Universities Physics Alliance AWAKE Oct Outline of talk Plasma characterization with THz-TDS Beam diagnostic: pulse length measurements THz-TDS/CTR Electron energy measurements Conclusions and future work

AWAKE Oct. 2012SCAPA Plasma characterization Plasma for AWAKE: Li or Rb vapour, density ≈ cm -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

AWAKE Oct. 2012SCAPA Plasma characterization The plasma complex dielectric constant dielectric properties (for non-magnetised plasma)  p is the plasma frequency, is the plasma collisional frequency, which depends on the temperature and density. Propagation constant Attenuation constant Measuring absorption and phase delay ( = L [  /c-k] ), plasma density and collisional frequency can be deduced

AWAKE Oct. 2012SCAPA Plasma characterization Experimental 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 ( cm -3 ) Ti:sapphire laser (1 mJ, 800 nm, 80 fs) to initiate THz emission from GaAs emitter 1 mm thick ZnTe crystal to sample the THz pulse Time range: >30 ps (sampling window) From the time resolve E(t)  E() Reference signal E 0 (): THz pulse preceding the discharge Jamison,…and Jaroszynski, J. Appl. Phys. 93, 4334, 2003

AWAKE Oct. 2012SCAPA Plasma characterization Jamison,…and Jaroszynski, J. Appl. Phys. 93, 4334, 2003 Experimental at Strathclyde: setup E(t) Phase shift: Field amplitude

AWAKE Oct. 2012SCAPA 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

AWAKE Oct. 2012SCAPA Beam diagnostic As for plasma: measurement based on THz EO-TDS Plasma density: direct spectroscopic method Electron bunch 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 ( mm)  bunching sub-ps length (Konstantin presentation yesterday) * Jamison,…, Jarsozinsky, Opt. Lett. 31, 2006

AWAKE Oct. 2012SCAPA Beam diagnostic Basic scheme: Spectral decoding Temporal decoding

AWAKE Oct. 2012SCAPA Beam diagnostic Not suitable for ultra short electron bunches (i.e. <500 fs FWHM) measure probe intensity I() known (initial) (t) infer I(t) simple setup Temporal resolution: bandwidth of the laser: e - -probe distance: Spectrometer resolution: Wilke et al. Phys. Rev. Lett (2002). 1.7ps FWHM Spectral decoding FELIX: 46 MeV, 200 pC Temporal resolution: 400 fs

AWAKE Oct. 2012SCAPA Beam diagnostic Temporal decoding: More complex setup Higher time-resolution sub 50 fs No frequency mixing Time resolution: independent of the chirped pulse duration Jamison,…, Jaroszynski, Opt. Lett. 18 (2003) Berden at al. PRL 11, (2004) FELIX: e -, 50 MeV, 1.5 mm

AWAKE Oct. 2012SCAPA Beam diagnostic This technique could be used to measure also the proton bunching Possible issues: 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

AWAKE Oct. 2012SCAPA Beam diagnostic Synchronization: Berden at al. PRL 11, (2004) Time jitter of the order of the bunch length

AWAKE Oct. 2012SCAPA Beam diagnostic CTR: shorter bunch length thin metal foil THz CTR: Coherent Transition Radiation e - beam 2 fs bunch measured at 1 m from source Peak current several kiloAmperes Coherent transition radiation spectrum gives bunch length

AWAKE Oct. 2012SCAPA Electron energy measurements Dual function device High resolution chamber Resolution – design ~ 0.1% Electron energy up to 105 MeV (B max = 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 (B max = 1.65 T) Can be scaled to higher energy and higher resolution Designed by Allan Gillespie / Allan MacLeod (ALPHA-X) Built by Sigmaphi (France)

AWAKE Oct. 2012SCAPA Electron energy measurements Other possibility: Indirect measurement using undulator radiation Ce:YAG crystal 300  10  1 mm Wiggins,.., Jaroszynski, Plasma Phys. Control. Fusion

AWAKE Oct. 2012SCAPA 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

AWAKE Oct. 2012SCAPA 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 Daresbury teams and other teams on electron beam and plasma diagnostics Theoretical studies of plasma wakefield accelerator using reduced and PIC codes

AWAKE Oct. 2012SCAPA Strathclyde (students and staff): Team: Dino Jaroszynski (Director), Salima Abu-Azoum, Maria-Pia Anania, Constantin Aniculaesei, Rodolfo Bonifacio, Enrico Brunetti, Sijia Chen, Silvia Cipiccia, David Clark, Bernhard Ersfeld, Paul Farrell, John Farmer, David Grant, Peter Grant, Ranaul Islam, Yevgen Kravets, Panos Lepipas, Tom McCanny, Grace Manahan, Martin Mitchell, Adam Noble, Guarav Raj, David Reboredo Gil, Anna Subiel, Xue Yang, 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,.... ALPHA-X project consortium Support: University of Strathclyde, EPSRC, CSO, EU Laserlab, STFC

AWAKE Oct. 2012SCAPA 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, Hartmut Ruhl, 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 Astrophysics Applications : Medical - Accelerator Driven Systems - Imaging Venue : University of Strathclyde, Glasgow, Scotland, United Kingdom November 13 and 14 : Thistle, Glasgow November 15 : Court Senate, University of Strathclyde, Glasgow

AWAKE Oct. 2012SCAPA Thank you