strathclyde programme: beam and plasma diagnostic
DESCRIPTION
Strathclyde programme: beam and plasma diagnostic. Prof. Dino Jaroszynski a nd Silvia Cipiccia University of Strathclyde. Outline of talk. P lasma characterization with THz-TDS Beam diagnostic : p ulse leng th measurements THz - TDS/CTR Electron energy measurements - PowerPoint PPT PresentationTRANSCRIPT
SCAPA [email protected]
Scottish Universities Physics Alliance
AWAKE Oct. 2012
Strathclyde programme:beam and plasma
diagnosticProf. Dino Jaroszynski
andSilvia Cipiccia
University of Strathclyde
SCAPA [email protected]
Scottish Universities Physics Alliance
AWAKE Oct. 2012
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. 2012
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Plasma characterization
Plasma for AWAKE:• Li or Rb vapour, 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
AWAKE Oct. 2012
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Plasma characterizationThe plasma complex dielectric constant dielectric properties (for non-magnetised plasma)
wp is the plasma frequency, n is the plasma collisional frequency, which depends on the temperature and density.
2 2 2 2 3 2 21 / ( ) / ( )p pv iv v w w w w w
Propagation constant Attenuation constant
Measuring absorption and phase delay (DF = L [w/c-k] ), plasma density and collisional frequency can be deduced
AWAKE Oct. 2012
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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
AWAKE Oct. 2012
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Plasma characterization
Jamison,…and Jaroszynski, J. Appl. Phys. 93, 4334, 2003
Experimental at Strathclyde:setup E(t)
Phase shift: Field amplitude
AWAKE Oct. 2012
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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. 2012
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Beam diagnosticAs 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 (0.165-1 mm)bunching sub-ps length (Konstantin presentation yesterday)
*Jamison,…, Jarsozinsky, Opt. Lett. 31, 2006
AWAKE Oct. 2012
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Beam diagnosticBasic scheme:
Spectral decoding
Temporal decoding
AWAKE Oct. 2012
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Beam diagnostic
Not suitable for ultra short electron bunches (i.e. <500 fs FWHM)
• measure probe intensity I() • known (initial) (t)Þ infer I(t) • simple setup• Temporal resolution:
• bandwidth of the laser:• e--probe distance:• Spectrometer resolution:
Wilke et al. Phys. Rev. Lett. 88 124801 (2002).
1.7ps FWHM
Spectral decoding
FELIX: 46 MeV, 200 pCTemporal resolution: 400 fs
AWAKE Oct. 2012
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Beam diagnosticTemporal 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. 2012
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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. 2012
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Beam diagnosticSynchronization:
Berden at al. PRL 11, (2004)
Time jitter of the order of the bunch length
AWAKE Oct. 2012
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Beam diagnosticCTR: shorter bunch length
thin metal foil
THz CTR: Coherent Transition Radiation
e- beam
Coherent transition radiation spectrum gives bunch length
AWAKE Oct. 2012
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Electron energy measurements
Dual function deviceHigh resolution chamberResolution – design ~ 0.1%Electron energy up to 105 MeV (Bmax = 1.65 T)High energy chamberUses upstream quadrupoles to aid focusingEnergy 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
• Designed by Allan Gillespie / Allan MacLeod(ALPHA-X)• Built by Sigmaphi (France)
AWAKE Oct. 2012
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Electron energy measurements
Other possibility:• Indirect
measurement using undulator radiation
Ce:YAG crystal300 10 1 mm
Wiggins,.., Jaroszynski, Plasma Phys. Control. Fusion 52 2010
AWAKE Oct. 2012
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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. 2012
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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. 2012
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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 WigginsCollaborators: 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. 2012
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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, GlasgowNovember 15 : Court Senate, University of Strathclyde, Glasgow
