The lensless Coherent Diffraction Imaging (CDI) technique has been developed significantly and is gaining time resolved potentials thanks to the advent of coherent and ultrashort pulses delivered by the X-ray free electron lasers (FEL). The shot-to-shot temporal and energy stability of the seeded-FEL pulses at Fermi@Elettra has opened extraordinary opportunities for CDI and in particular for Resonant Coherent Diffraction Imaging (R-CDI), overcoming some of the limitations imposed by the partial longitudinal coherence of the SASE-FELs.In addition, the multiple (linear and circular) polarization of Fermi-FEL pulses is an added value to explore specific contrast mechanisms, relevant to the spin and orbital sensitive electronic transitions.

The MiniTIMER compact split and delay line can be set up inside the DiProI chamber before the sample region to split each FEL pulse into to branches and recombine them on the sample with tunable incidence angle and delay (in collaboration with the EIS-TIMER beamline). This set up has been used for transient grating, coherent anti-Stokes Raman scattering and time-resolved magnetic scattering experiments.
The typical crossing angle between the two beams is of about 6° and the delay can be scanned in the range of ±500 fs.

Additional Lightsources

Seed Laser for Users (SLU)

Laser type
Ti:Sapphire
Central Wavelength/Energy
795 [nm]
Wavelength fluctuations
1 * 10-3 [%]
Spectral Bandwidth FWHM
18 [nm]
Tunability
1 [%]
Beam shape
Gaussian
Other beam shape
M2<1.5
Pulse duration FWHM
65 [fs]
Polarisation
Linear Horizontal, Linear Vertical, Circular
Other polarisation
All linear and circular polarizations available
Pulse repetition rate
50 [Hz]
Maximum pulse energy
1.5 * 10-3 [J]
Pulse energy fluctuations
5 * 10-3 [sigma]
Peak power
20 * 109 [W]
Peak fluence on target
10 [J/cm2]
Special modes
2nd and 3rd harmonics (~390 and ~260 nm) available
Endstations or Setup

DiProI

Microscopes
Sample observation color microscope.
3 mm field of view.
3 um resolution.
Base Pressure
3 * 10-7 [mbar]
Detectors Available
PI-MTE
Basler Scout
Balanced Photodiodes
Endstation Operative
Yes

Sample

Sample Type
Crystal, Amorphous, Other: Aerosolized nanoparticle
Mounting Type
Solid samples can be fixed on a 40 x 40 mm sample holder by clamps or by Kapton or carbon tape. The sample holder can be placed in position on the sample manipulator by an automatic clamping system.
Required Sample Size
X = 1000 [um], Y = 1000 [um], Z = 0.1 [um]

Manipulator or Sample stage

Degrees Of Freedom
6
Translator Stages
3
Cradles
1
Positioning Precision
X = 1 [um], Y = 1 [um], Z = 1 [um]
Range Of Movement
X = 100 [mm], Y = 30 [mm], Z = 30 [mm]

Magnetic Fields

Max AC Field
25 * 10-3 [T]
DC Fields
An electromagnet can be powered with currents between -5 A and 5 A, switching the magnetic field between pulses of the FEL source working at 50 Hz
Max DC Field
25 * 10-3 [T]
Detectors

Balanced Photodiodes

Type
Large-Area Balanced Photodetector, UV-Enhanced Si, 190-1100 nm, commercial model PDB220A2/M from Thorlabs
Pixel Size
X = 4.1 [um], Y = 4.1 [um]
Passive or Active (Electronics)
Active

Detection

Detected Particle
Electron

Basler Scout

Type
Basler Scout scA1600-28gm commercial detectors
Pixel Size
X = 4.4 [um], Y = 4.4 [um]
Array Size
X = 1626 [pixel], Y = 1236 [pixel]
Passive or Active (Electronics)
Active
Dynamic Range
40 * 103 [Counts]

Detection

Detected Particle
Electron

PI-MTE

Type
In vacuum, windowless CCD (for optical/EUv/x-rays)
Description
Commercial device (by Princeton Instruments).
Al(200 nm thick), Zr(150 nm thick) or Pd(150 nm thick) filters are available to be placed in front of the CCD chip to filter visible and IR light.
Pixel Size
X = 13.5 [um], Y = 13.5 [um]
Array Size
X = 2048 [pixel], Y = 2048 [pixel]
Passive or Active (Electronics)
Active
Dynamic Range
40 [counts]

Detection

Detected Particle
Photon
contacts
Emanuele Pedersoli
Flavio Capotondi
Techniques
Diffraction
  • Time-resolved studies
Emission or Reflection
  • Time-resolved studies
Imaging
  • X-ray holography
  • X-ray microscopy
Scattering
  • Coherent scattering
  • Magnetic scattering
  • Small angle scattering
  • Time-resolved scattering
Disciplines
Physics
  • Other - Physics
control/Data analysis
Control Software Type
  • Tango, Labview
Data Output Type
  • CCD images, oscilloscope waveforms, picoammeter intensities, FERMI machine data.
Data Output Format
  • HDF5 files containing data structure with the pertinent information about the machine, the experimental station and the sample. Data can be numbers, vectors, matrices or tensors. Some data are available for each single FERMI pulse, some others are acquired with integrative measures.
Softwares For Data Analysis
  • Matlab, Python. Basic analysis tools are available for standard experiments. More advanced software can be developed for specific experiments by software staff at Elettra-Sincrotrone Trieste in collaboration with users.
Possibility To Connect External Endstation
Yes
in partnership with