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Injection system of the 4GLS light source B.L. Militsyn on behalf of 4GLS team ASTeC STFC Daresbury Laboratory ERL07 Workshop, Daresbury, 21.05.2007-25.05.2007.

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Presentation on theme: "Injection system of the 4GLS light source B.L. Militsyn on behalf of 4GLS team ASTeC STFC Daresbury Laboratory ERL07 Workshop, Daresbury, 21.05.2007-25.05.2007."— Presentation transcript:

1 Injection system of the 4GLS light source B.L. Militsyn on behalf of 4GLS team ASTeC STFC Daresbury Laboratory ERL07 Workshop, Daresbury,

2 2/ Outline Introduction 4GLS light source Injection system of 4GLS XUV-FEL normal conductive RF photoinjector VUV-FEL High Average Current DC NEA photocathodes based injector 4GLS laser system IR-FEL thermionic injector Status and perspectives Conclusion B.L. Militsyn, ERL07 Workshop, Daresbury,

3 3/ 4GLS Layout B.L. Militsyn, ERL07 Workshop, Daresbury,

4 4/ XUV-FEL branch of 4GLS B.L. Militsyn, ERL07 Workshop, Daresbury, Photon energy range, eV Peak power, GW Photon pulse length, fs22 Repetition rate, kHz1 Beam energy 750 MeV

5 5/ XUV-FEL injector B.L. Militsyn, ERL07 Workshop, Daresbury, Beam parameters at the entrance of main linac Bunch charge, nC1.0 Bunch repetition rate, kHz1.0 Beam energy, MeV210 Normalised emittance, π·mm·mrad<2 Uncorrelated energy spread, %<0.05 RMS bunch length (σ ), ps~2

6 6/ Normal conductive 1.5-cell RF photocathode gun B.L. Militsyn, ERL07 Workshop, Daresbury, Distribution of accelerating RF and focusing magnetic field in the gun

7 7/ ASTRA simulation of the RF gun B.L. Militsyn, ERL07 Workshop, Daresbury, Simulation parameters Laser spot diameter, mm4 Spatial laser spot distributionUniform Temporal laser pulse shapeFlat-top Laser pulse length, ps20 Rise time, ps2 Initial rms beam energy spread, V0.4 Maximum RF accelerating field, MV/m40

8 8/ ASTRA simulation of the XUV-FEL injector B.L. Militsyn, ERL07 Workshop, Daresbury,

9 9/ ASTRA simulation of the XUV-FEL injector B.L. Militsyn, ERL07 Workshop, Daresbury,

10 10/ Laser for the XUV-FEL injector B.L. Militsyn, ERL07 Workshop, Daresbury, Required energy of laser pulse is given by: For an CsTe 2 photocathode Q e =1% at =262 nm : Wavelength, nm262 Repetition rate, kHz1.0 Pulse shapeFlat top Maximum rise time, ps2 Pulse length, ps10 Laser pulse energy, µJ1

11 11/ VUV-FEL branch of 4GLS B.L. Militsyn, ERL07 Workshop, Daresbury, Photon energy range, eV3-10 Peak power, MW350 Photon pulse length, fs64 Repetition rate, MHzn*4.33 Beam energy 550 MeV Maximum photon energy, eV80 Average flux, 1/s/0.1% bp 1.0*10 15 Repetition rate, GHz1.3

12 12/ VUV-FEL injector B.L. Militsyn, ERL07 Workshop, Daresbury, Beam parameters at the entrance of main linac Bunch charge, pC77 Bunch repetition rate, GHz1.3 Operation modeCW Beam energy, MeV10 Normalised beam emittance, π·mm·mrad < 2 Uncorrelated energy spread, %< 0.1 Bunch length, ps 5

13 13/ High voltage DC photocathode gun B.L. Militsyn, ERL07 Workshop, Daresbury, Parameter of the photocathode gun Gun voltage, kV500 Average beam current, mA100 Bunch repetition rate, GHz1.3 RMS laser pulse length, ps20 Laser pulse shapeGaussian Estimated operational life time, hours27 Estimated rms transverse emittance, π·mm·mrad2.8 Estimated rms bunch Length, ps30

14 14/ Photocathode preparation set-up B.L. Militsyn, ERL07 Workshop, Daresbury, Required photocathodes: NEA III/V semiconductor Transmission mode High quantum efficiency Fast response High emission current density

15 15/ Photoemission from thick NEA photocathodes B.L. Militsyn, ERL07 Workshop, Daresbury, Photoemission from thick NEA photocathodes illuminated by green light by the courtesy of A.S. Terekhov Energy distribution of electrons emitted from bulk GaAs photocathodes according to measurements made at Max Planck Institut für Kernphysik (MPI-K), Heidelberg, Germany.

16 16/ Photoemission from thin NEA photocathodes B.L. Militsyn, ERL07 Workshop, Daresbury, nm 1000 nm 2.3 ps 30 ps Data from Mainz: experiment, diffusion model if dL - thermalization length hot photo- electrons increase transverse energy spread

17 17/ Beam dynamics in the VUV-FEL injector B.L. Militsyn, ERL07 Workshop, Daresbury,

18 18/ Laser for VUV-FEL injector B.L. Militsyn, ERL07 Workshop, Daresbury, For GaAs photocathodes <850 nm, for =520 nm Wavelength, nm520 Repetition rate, GHz1.3 RMS pulse with, ps10 Average laser power for Q e =10%, W2.3 Average laser power for Q e =1%, W23 Average laser power for Q e =1%, =0.7, W33 Timing jitter, fs100

19 19/ Time structure of the beam in the main linac B.L. Militsyn, ERL07 Workshop, Daresbury,

20 20/ 4GLS laser system B.L. Militsyn, ERL07 Workshop, Daresbury, by the courtesy of G. Hirst

21 21/ IR-FEL branch of 4GLS B.L. Militsyn, ERL07 Workshop, Daresbury, Wavelength, m Repetition rate, MHz13 Peak power, MW3-20 Photon pulse length, ps Switch yard frequency, Hz100 Beam energy MeV

22 22/ IR-FEL injector B.L. Militsyn, ERL07 Workshop, Daresbury, Bunch charge, pC200 Bunch repetition rate, MHz13 Peak current, A8 to 80 Energy, MeV25 to 60 Normalised emittance, π·mm·mrad < 10 RMS energy spread, %< 0.1 RMS bunch length, ps1 - 10

23 23/ Thermionic emitter B.L. Militsyn, ERL07 Workshop, Daresbury, Grid modulated 6 mm LaB 6 emitter Formation of the grid voltage

24 24/ ASTRA simulation of a 400 kV thermionic gun B.L. Militsyn, ERL07 Workshop, Daresbury,

25 25/ Beam in the transverse and longitudinal phase spaces B.L. Militsyn, ERL07 Workshop, Daresbury,

26 26/ Status and perspectives B.L. Militsyn, ERL07 Workshop, Daresbury, XUV-FEL injectorR&D VUV-FEL injector Photocathode gunDrawing room Preparation facilityDrawing room PhotocathodesR&D Laser systemR&D High voltage power supplyR&D Test beam lineERLP test beam line IR-FEL injectorR&D

27 27/ Conclusion B.L. Militsyn, ERL07 Workshop, Daresbury, Injection system of 4GLS requires state of the art and beyond electron sources, laser and synchronisation devices Though requirements for injector for XUV-FEL very close to the parameters of BESSY-PITZ project some research are required in thew derection of High power gun cavity High repetition rate low jitter laser system Injector for VUV-FEL requires additional research in the direction of Photocathode development Photocathode preparation and manipulation technique Very high voltage photocathode gun design High frequency high power laser system IR-FEL injector may be build on the bases of well known grid modulated thermionic gun


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