SPARX FEL:How ENEA can contribute

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Giuseppa Ferretti
5 anni fa
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1 SPARX FEL:How ENEA can contribute to? G.DATTOLI Dipartimento Tecnologie Fisiche e Nuovi Materiali Via E. Fermi Frascati (Italy) DATTOLI@frascati.enea.it Rome March

2 Citation:. The realization of a FEL operating in the VUV-X region and all the associated technical problems is not the main point.. Here we are attempting a crucial experiment, may be unique in the history of science: We are trying to put together different italian scientific institutions, Universities and funding agencies to realize something and it is not important what Any output would be a success of un-precedent importance

5 It is evident that all institutions will bring into the collaboration their wealth of experience: Frascati- Rome area the natural environment Frascati: (CNR, ENEA, INFN) Pioneering in Synchrotron radiation FEL 32 years or more (more I found an internal note (INFN) by M. Sands may be 1973, fel summary of what I know ) ENEA, INFN, ADONE crucial experiment on third harmonic gain

6 The long way to high gain FEL devices Nf ~ Ne Nf ~ Ne Nm Nf ~ Ne Nm^2 Nf ~ (Ne Nm)^2

7 In between UND & SASE: Oscillators

8 The promises of an X-FEL: Ultra-Bright, Ultra-Fast

9 What have we done? Soft X-Ray Microscopy Advances in soft X-ray imaging (l > 1 nm, E < 1 kev) were introduced for imaging of internal structure of biological samples in their normal living state, at a high spatial resolution and avoiding all specimen preparation X-Ray Source, Optics and Detectors

10 ENEA X-ray imaging: the short wavelength gives the potential for high-resolved resolution imaging. The great progress achieved and the future perspectives are now enough mature to be applied to a number of different scientific fields, such as life sciences, nanoscience and nanotecnology, material engineering, cultural heritage, security, etc.

11 Sources Laser Plasma Sources X-FEL will allow to plan imaging experiments of biological specimens in very simple geometries, e.g. lensless and single-shot shot configurations (for in vivo experiments), by using both absorption and phase contrast methods, with very high spatial-time time resolution. Due to the coherence of the X-FEL beam and the high brightness, biological investigation can be performed by single shot holography experiments as a method for a high resolution 3D imaging.

12 Promises SPARX source High Brightness: 3-8x10 30 Phot/s/0.1%bw/(mm-mrad) 2 Short duration: ~ 100 fs λ = 3-5 nm (water and carbon window) Coherence. High Brightness SPARX peculiarities Imaging with high spatial resolution of living biological samples in single shot experiments Short duration Spectral emission Coherence Imaging of biological specimens with high time resolution, reducing radiation damages Natural contrast of living biological specimens Holography experiments for high resolution 3D imaging, even for in vivo specimens in single-shot configuration In all X-ray imaging configurations, the spatial resolution and the dynamic range of the detector plays a fundamental role.

13 . SPARX - spectral emission Penetration depth in water and in biological material Water Water Window Window nm nm (0.28 ( kev) kev) Oxygen K edge Carbon K edge Carbon Carbon Window Window nm nm (0.25 ( kev) kev) Emission wavelength of FEL X Soft X-ray 1-4 nm ( ev) EUV 4 60 nm ( ev)

14 Detectors (ENEA) Proposal for a novel X-ray imaging detector, which is currently under further development for applications in biology, photonics and material science, as well as in the characterization of intense X-ray sources. This detector is based on optically stimulated luminescence of color centers in lithium fluoride (LiF) films and crystals. International Patent WO 2004/ A1 A method for detection of micrometric and sub-micrometric images by means of irradiation of a mask or of a biological specimen with ionizing radiation.

15 But the future is much more challenging Temporal characteristics of a SASE FEL Optical manipulation of a frequency-chirped SASE Compression Slicing: single-stage and two-stage Statistical analysis Electron bunch manipulation Spatial chirp Enhancing undulator wakefield Selective emittance spoiling (slotted spoiler) Sub-femtosecond possibilities

16 . Problems with spiking. And statistical fluctuations, Sparc will be a good test facilty To learn how to control the Fluctuating modes (number of modes ~ 700) statistical fluctuation σ w /W ~ 4 % 1 % of of X-Ray X-Ray Pulse Pulse Length Length

17 Do not forget to be ambitious!!!. Small signal gain G= P intra /P intra Start-up: (1+G 0 ) R 1 R 2 >1 (R 1 & R 2 : mirror reflectivity) Saturation: (1+G sat ) R 1 R 2 =1 Synchronism Spacing between electron bunches=2l/n ( L: length of the cavity)

18 Ambitions E=7GeV, λ=1å Q=19 pc (Ip=3.8A), N u =3000 Mirror reflectivity=90% Saturation power=19 MW E=7GeV, λ=1å Q=40 pc (Ip=8 A), N u =3000 Mirror reflectivity=80% Saturation power=21mw Gain (%) Saturation Point Gain (%) Saturation Point E E E E E E E E E E+07 Intra Cavity Power (W) E E E E E E E E E E+07 Intra Cavity Power (W)

19 Sapphire 14.3 kev.

20 Are we still able to dream?

21 Dream FEL

22 Dream param.

23 Do not forget the Terahertz spectral range The THz gap is getting crowded! Radio waves Micro waves IR Visible X-rays 10 3 kilo 10 6 mega 10 9 giga tera peta exa 1 Terahertz: 300 µm 4 milli- electron volts. Electronic sources Free electron sources Frequency [Hz] Optical sources 20% of the average thermal energy available at room temperature.

. LiF-based detector for X-rays A novel X-ray imaging detector has been recently proposed, tested and it is currently under.

This detector is based on optically stimulated luminescence (OSL) of color centers in lithium fluoride (LiF) films and crystals.

tunable in a broad 0, 4 wavelength range in the VIS and NIR.

24 . LiF-based detector for X-rays A novel X-ray imaging detector has been recently proposed, tested and it is currently under.development for application in photonics, biological investigations and material science, as well as in the characterization of intense X-ray sources. This detector is based on optically stimulated luminescence (OSL) of color centers in lithium fluoride (LiF) films and crystals. LiF is of particular interest because : 1, 0 it is almost non-hygroscopic 0, 8 it can host point defects stable at room temperature , 6 + it can host laser active color F centers F F F tunable in a broad 0, 4 wavelength range in the VIS and NIR. Absorption 0, 2 Optically active 0, 0 defects in LiF can be generated by ionizing radiation 1, 0 like charged particles (electrons and ions), as well as gamma and X- 0, 8 rays. Emission 0, 6 F center is an anion vacancy occupied by an electron; they are not 0, 4 + optically active centers F 3 0, 2 F 2 F 2 and F 3 + centers F F 3 F 2 0, 0centers are optically active F-aggregates consisting in two electrons bound to two and three close anion vacancies, W a v e l e n g t h ( n m ) respectively F 2 - F 2 CC E 3 E 0 U p W 32 W 10 1/ sp sp ~ 18 ns W32 and W 10 >> 1/ sp E3 - E 0 = 2.79 ev E2 - E 1 = 1.85 ev E 2 E 1 F - Li + e -

25 COMPACT FEL layout COMPACT FEL layout λ = λ u (1+K 2 )/ γ 2 (1± ) Steering Coils Quadrupoles Undulator Accelerator waveguide To operate in the THz region: Low electron energy Short undulator length Electron transparent mirrors (ETM) wire-grids Waveguide resonator Mesh Coupler

Development of compact THz sources Development of compact THz sources The THz Compact FEL at ENEA Frascati Tunability 90 to 150 GHz by varying the resonator length Wide bandwidth operation ( ν/ν

26 Development of compact THz sources Development of compact THz sources The THz Compact FEL at ENEA Frascati Tunability 90 to 150 GHz by varying the resonator length Wide bandwidth operation ( ν/ν ν/ν=8% P = 10 kw in 60 ps, P = 1.5 kw in 4 µs) Single frequency operation (P= 300 W in 4 µs) FEL-CATS (Compact Advanced THz Source) FEL-CATS utilises a high efficiency generation scheme based on the mechanism of coherent spontaneous emission with energy-phase correlation. Tunability between THz ( µm) ν/ν=20% P > 10 kw in 15 ps Single pass device - No resonator needed! Phys. Rev. Lett. 93, (2004)

27 Imaging & Microspectroscopy

THz radiation and Basal Cell Carcinoma Researchers at TERAVIEW developed a THz imaging system, working in reflection, able to provide a quasi-3d image of suspect tissues.

Histological analysis confirmed the results of THz scans. 4mm inflammation Visible image n2 n1 4mm TPP, t = -1.74ps i1 i2 d2 d1 x Time post pulse image 0.15 0.20 0.25 0.30 0.35 0.40 0.

28 THz radiation and Basal Cell Carcinoma Researchers at TERAVIEW developed a THz imaging system, working in reflection, able to provide a quasi-3d image of suspect tissues. Diseased tissue appears to behave differently with respect to healthy tissues, showing a marked contrast, mainly due to water absorption in the sample. Histological analysis confirmed the results of THz scans. 4mm inflammation Visible image n2 n1 4mm TPP, t = -1.74ps i1 i2 d2 d1 x Time post pulse image TPP = E(t) / E min Mean (a.u) TPP t = -1.74ps Area statistics d1 d2 i1 i2 n1 n2 Sample Area (courtesy of Teraview Ltd) R. Woodward et al, Phys Med Biol. 2002

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