Thomson'Backsca,ering'Experiments'at'LOA' Andreas'Dpp' - PowerPoint PPT Presentation

LA 3 NET TW3 : Novel Acceleration Techniques HZDR,'Dresden,'April'2014' Thomson'Backsca,ering'Experiments'at'LOA' Andreas'Döpp' adoepp@clpu.es'

2 X-rays in daily life X-rays in daily life … are b … ar e based ased on Br on Bremsstrahlung and K-shell emission lines! emsstrahlung and K-shell emission lines! Industrial imaging Industrial imaging ' Medical imaging Medical imaging ' 10 keV 10 keV ' 100 keV 100 keV ' 1 MeV 1 MeV ' Airport security Airport security ' Mammography ' Mammography K α ( ( 42 42 Mo) ~ 17.4 Mo) ~ 17.4 keV keV keV K α' ( 45 45 Rh) ~ Rh) ~ 20.1 20.1 keV Ener Energy [10 keV] gy [10 keV] CT scanner CT scanner ' ~70 keV ' ~70 keV X-ray absorption X-ray absorption colour colour scale scale Dental radiography ' Dental radiography high high - metal band ( - metal band (Z ef eff >18) >18) 15-30 keV 15-30 keV ' medium medium - inor - inorganic band ( ganic band (Z ef eff >10) >10) ganic band (Z ef eff <10) <10) low low - or - organic band

3 X-rays in daily life X-rays in daily life …have drawbacks due to br …have drawbacks due to broadband spectrum oadband spectrum Some advantages of (Quasi-) Monochromatic X-ray - Better image contrast - Less dose deposed in material - Ideal for phase contrast imaging - Ideal for dual-energy imaging Polychromatic X-ray produce artifacts in CT (beam hardening) Sci. Rep. 3, (2013). Achterhold, K. et al. from : http://individual.utoronto.ca/s_richard/DEimaging.htm How do we get How do we get monoener monoenerget getic ic X-ray? X-ray?

4 Synchr Synchrotr otron rad on radiat iation ion Basic ideas : - Frequency ( ω ) and trajectory (t) are coupled - Sinusoidal trajectory sin ω 0 t should lead to some monoenergetic emission? - Use doppler upshift to get high frequencies How can we get an electron on a sinusoidal trajectory? � � � � + � � � × � � � = � � Lor Lorentz For entz Force : ce : Pur Purely electric ely electric Electr Electromagnet omagnetic ic Pur Purely magnet ely magnetic ic (magnet (magnetic insert ic insertion ion (Plasma wave wiggler Plasma wave wiggler) Compton / Thomson Compton / Thomson devices) devices) scat scattering tering

5 Inverse Thomson Inverse Thomson Backscat Backscattering tering (Optical) (Opt ical) Undulator Undulator equat equation ion � + � � � � � � � + � � � � � � = � � � ( � − � ��� ( � )) Doppler effect Doppler ef fect – moving receiver – moving source '''''λ’’ = λ ’ x' (1- β cos θ ) % %≈ λ 0 x' (1+ γ 2 θ 2 ) / 2 γ 2 ' λ’' = γ L1' λ 0 /' (1- β cos ϕ ) ' e - e - ϕ θ < 0.1Å / 
 > 10 keV ' ~ 800 nm / 
 ħω 0 ' ~ 1.5 eV ' Angle between observer and electron Angle between ‘undulator’ and electron direction (small angle approximation)

6 Inverse Thomson Inverse Thomson Backscat Backscattering tering (Optical) (Opt ical) Undulator Undulator equat equation ion � + � � � � � � � + � � � � � � = � � � ( � − � ��� ( � )) Strong motion in transverse plane effects longitudinal motion. � � ( � ) = � � � � ( � ) � � � � + � � + � � � � � ��� ( � � � ) � � � ��� � � � � � � � Effective Lorentz factor γ ’ = γ / (1+ a 0 2 /2) 1/2 a 0 is equivalent to peak angular deflection parameter K . Difference to K in conventional undulators : a 0 evolves during interaction

7 Inverse Inverse Thomson Thomson Backscat Backscattering tering counter counter-pr -propagat opagating u ing using sing Plasma-Mirr Plasma-Mirror or up to MeV range

8 Inverse Inverse Thomson Thomson Backscat Backscattering tering counter counter-pr -propagat opagating u ing using sing Plasma-Mirr Plasma-Mirror or ~ 1.6 J, ~30 fs ~ 1.6 J, ~30 fs (65 % of 2.5 J) (65 % of 2.5 J) Lanex Lanex Scr Screen een ~ 0.9 J on tar ~ 0.9 J on target get Spherical Spherical mirr mirror or (700 mm) (700 mm) ~ 50-55 % ~ 50-55 % Princeton Instruments of energy in of ener gy in Quad-RO: 4320 focal spot focal spot 2084 x 2084 imaging array | 24um x 24um pixels

9 Inverse Thomson Inverse Thomson Backscat Backscattering tering counter counter-pr -propagat opagating u ing using sing Plasma-Mirr Plasma-Mirror or Image Processing Background noise substracted Signal averaged to mean out local noise Reconstruct Intensity Pr Reconstruct Intensity Profiles ofiles - for free areas (holes) - covered by 5.1mm Cu Interpolate signal using 2D cubic 2D cubic interpolat interpolation ion

10 Inverse Inverse Thomson Thomson Backscat Backscattering tering counter counter-pr -propagat opagating u ing using sing Plasma-Mirr Plasma-Mirror or Free 5mm Cu Spectre d lectrons n 204, 100 lignes 3.5 x 10 7 Foil at the edge of Gas jet 140 MeV, 142 pC 3 2.5 dE (e-/MeV) 2 dN e 1.5 1 0.5 0 0 50 100 150 200 250 E (MeV)

11 Inverse Inverse Thomson Thomson Backscat Backscattering tering counter counter-pr -propagat opagating u ing using sing Plasma-Mirr Plasma-Mirror or Free 5mm Cu Spectre d lectrons n 296, 100 lignes 2.5 x 10 7 Foil 12 mm behind edge of Gas jet 101 pC 2 1.5 dE (e-/MeV) dN e 1 0.5 0 0 50 100 150 200 250 E (MeV)

12 Inverse Inverse Thomson Thomson Backscat Backscattering tering counter counter-pr -propagat opagating u ing using sing Plasma-Mirr Plasma-Mirror or Simulation performed using 5000 test particles. Δ E/E=0.05. Divergence 5mrad. Scattering beam a 0 =1, 30 fs duration, 20 um FWHM. Filters show 50 % signal from < 100 keV From the electrons we miss on the spectrometer?

13 Acknowledgements Acknowledgements people | institutions | programs involved Laboratoir Laboratoire d’Opt ’Optique ique Appl Appliquée iquée Kim T Kim Ta a Phuoc Phuoc, Cedric , Cedric Thaury Thaury, , Emil Emilién ién Guil Guillaume, laume, Jean-Philippe Goddet, , Amar Tafzi, Remi Lehe, Igor Igor Andriyash Andriyash, Agustin Lifschitz, Victor ictor Mal Malka ka Centr Centro de o de Láser Láseres es Pulsados Pulsados | Universidad de Salamanca | Universidad de Salamanca Camilo Camilo Ruiz, Enrique Ruiz, Enrique Conejer Conejero This work is funded is funded by the European Commission via LA 3 NET under contract PITN-GA-2011-289191