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logo CRISTAL

CRISTAL is an undulator-based multi-technique diffraction beamline, dedicated to studies of the structural properties of condensed matter, on different length and time scales, possibly in non-ambient conditions. All the standard techniques for structural analysis on single crystals and powders are proposed, as well as more advances techniques like coherent diffraction imaging and time-resolved diffraction in a pump-probe scheme.

X-ray diffraction is one of the most powerful method for structure determination.

CRISTAL is a high-performance undulator-based beamline providing state-of-the-art techniques such as coherent diffraction, time-resolved diffraction, high angular and high spatial resolution diffraction.

The three instruments are: 

  • A 2-circle power diffractometer equipped which multi-analysers
  • A 4-circle diffractometer for precise high-q measurements
  • A 6-circle diffractometer, offering an exceptional experimental potential.

Time-resolved pump-probe experiments are operational at the picosecond resolution, and soon (2014) at the femtosecond resolution

A broad scientific community initiated this beamline in complementarity with ESRF. 

Team

BERENGUER
BERENGUER Felisa
Scientifique de Ligne De Lumière
ELKAIM
ELKAIM Erik
Scientifique de Ligne De Lumière
FERTEY
FERTEY Pierre
Responsable Ligne De Lumière
JARNAC
JARNAC Amelie
Post-Doc
LAULHE
LAULHE Claire
LEGRAND
LEGRAND Fabien
Assistant Ingénieur de Ligne De Lumière

Technical data

Energy range

5 – 30 keV

Energy Resolution (∆E/E)

ΔE/E ~10-4

Source

In-vacuum undulator U20

Optics

Double Crystal Monochromator

Beam spot size on the sample

Min V x H = 30 μm x 450 μm

Min with fully illuminated Fresnel Zone Plates: V x H = 0.3 μm x 0.8 μm

Min with fully coherent beam (partial illuminated Fresnel Zone Plates): V x H = 1 μm x 2 μm

Max V x H = 1200 μm x 1500 μm

distances are fwhm values

 

Diffractometer
  • 2-Circle diffractometer
  • 4-Circle diffractometer 
  • 6-Circle diffractometer  
Detectors

Pontual detcetors
2D detectors

Sample Environment
  • Pression  
  • Temperature 
  • Miscellaneous

Scientific opportunities

Powder diffraction

High angular resolution for ab initio structure determination 
High q measurements for pair distribution function (pdf) 
Kinetics of solid-solid phase transformations

Single crystal diffraction

Single crystal structure determination

Incommensurate crystals, quasi-crystals 
Thin films 
Diffuse scattering

Electron density 
measurements

Low temperature (30K) and high q diffraction measurements for charge density analysis.

Coherent diffraction

X-Ray Coherent Diffraction Imaging (Bragg geometry)
BCDI on sub-micrometric objects: strains and defects mapping
Ptychography 

Micro diffraction Micro diffraction imaging
Pump-probe time-resolved 
diffraction

10 ps / 80 ps time resolution diffraction 

pump: 800 nm and 400 nm, 5 mJ-25 fs laser pulses@1kHz
 

Undulator

The source of the beamline is an U20 undulator, containing 98 periods of 20 mm. 
The accessible energy range is from 4 keV to 30 keV.

The figure displays the measured flux on the whole energy domain. This measurement was performed using a calibrated X-ray camera.
The data are corrected by the absorption of the Be windows still inserted on the beamline and the residual air between the camera and the exit window.

Measured spectrum of the CRISTAL U20

Measured spectrum of the CRISTAL U20, with absorption corrections. Harmonics from H3 (4.29 keV) to H20 (28.6 keV) are shown.

Monochromator

CRISTAL monochromator

CRISTAL monochromator

The monochromator is a fixed exit DCM from the Accel company, equipped with two pairs of crystals: a pair of Si(111), with a sagittal bender on the second crystal, for energies between 4 and 30 keV, and a pair of flat Si(311) for energies between 8 to 60 keV. 
The first crystals are cooled down by a liquid nitrogen closed loop circuit (Cryotherm company). The tuning of the monochromator is ensured by a piezo-actuator, controlled by a feed-back loop on the intensity measured downstream. The feed-back loop is performed by a “Mostab”, developed at Desy, which was provided by Accel. 

CRISTAL monochromator The curves shown below display the Cu K-edge absorption spectra (8.979 keV), with Si(111) and Si(311) DCMs before energy calibration. The visibility of the first peak indicates the good resolution of both DCMs. In the right part of the figure, the derivatives of repeated spectra measured on June 6th and June 10th, 2007 show a 0.5 eV reproducibility in energy (5 10-5). However, additional measurements have shown that after a long beam loss or a large angular displacements of the DCM, the reproducibility could deteriorate down to ΔE/E = 10-3, requiring an energy re-calibration if accuracy is needed. 

monochromateur

Cu K-edge measured with the Si(111) (left) and the Si(311) (middle) DCM. On the right-hand side, comparision of the derivatives of the near-edge region measured at t0 and t0+4 days.

Cu K-edge measured with the Si(311)

Cu K-edge measured with the Si(311)

comparision of the derivatives of the near-edge region measured at t0 and t0+4 days.

comparision of the derivatives of the near-edge region measured at t0 and t0+4 days.

Mirrors

CRISTAL mirror system

CRISTAL mirror system

The mirror system consists of two horizontal 300 mm long Si mirrors (SESO), placed in a dedicated hutch. The first one is bendable. These mirrors are coated by Rh and Pt tracks. This allows an harmonic rejection in the whole energy range. Slope errors are about 0.40 µrad for both mirrors. The minimum beam FWHM has been measured to be 27 µm @ 8 keV on the 6-circle.

Calculated reflectivity of the CRISTAL mirrors

Calculated reflectivity of the CRISTAL mirrors

2-Circle diffractometer

Description and characteristics

Most of the powder diffraction experiments are performed on the 2-circle diffractometer. This dedicated instrument was initially optimized to record high angular resolution diagrams for ab initio structure determination, microstructure analysis or to study phase transitions, thanks to its multi-analysers detector (21-Si(111) crystals). A complete powder diagram up to 100° 2q can be measured in less than 1h.

The curve below gives the instrumental resolution determined from the full width at half maximum of the Bragg peaks extracted from the powder diagram of a LaB6 sample (NIST-SRM660, cubic Pm3m) at 25 keV.

Instrument Résolution Function (IRF)

Instrument Résolution Function (IRF) at 25.55 keV as a function of the 2theta diffraction angle.

Recently (2018), a curved pixel detector (9x Dectris Mythen II modules, positioned on a cylinder with a radius of 720 mm) was added to the detection circle, providing a 50° 2θ coverage with small gaps (0.5°) or a 25° coverage with no gaps when a non-symmetrically position with respect to the incident beam direction is adopted. A good angular resolution is kept (<0.02° 2θ) is kept. Due to its very short readout time (2ms), a complete powder diagram (up to 2q = 50°) can be acquired within a few seconds if the detector movements are optimized.

For PDF experiments, to achieve high Q values (> 25Å-1), the highest energies available are used (28 to 30 keV), combined to a scan of the detector position to at least 120° 2θ. Using the Mythen detector, a complete diagram for pdf analysis purposes can be obtained within 1 hour (6 h with the multi-analysers).

4-Circle diffractometer

View of the 4-circle diffractometer

View of the 4-circle diffractometer equipped with a gas streamer (CryoIndustries of America) to cool the sample. Insert: axes names.

The purpose of the project was to provide the users (crystallographers, chemists, physicists, mineralogists) with a 4-circle diffractometer allowing an easy, fast and precise data collection on single crystals in different sample environments. The instrument specially built for the beamline has resulted from the association of two companies each well known in their area: Newport (Microcontrol) for the goniometer part and Agilent (Oxford Diffraction) for the detector and data analysis software. 
The data are measured using the oscillation method: for each image acquisition, the diffraction signal is measured while the sample is rotated at constant speed over a small angular range (typically 1°). Therefore, the requested main characteristics of this instrument are: 

  • a 2D CCD detector permanently mounted, which can be translated (80 mm < dtx < 340 mm) 
  • high accuracy of motions, 
  • very small sphere of confusion to be able to study micro-crystals (Ø < 10 µm), 
  • data acquisition/analysis software package standard and familiar to most users. 


All the motors are DC motors driven with Newport XPS controllers. Let us recall that the Cylinder of Confusion (CoC) is the largest diameter of the cylinder described by the sample during the motion of the concerned rotation axis, and the Sphere of Confusion (SoC) the largest dimension of the volume described by the sample during the motion of all the axes.

6-Circle diffractometer

Newport 6-circle diffractometer,

Newport 6-circle diffractometer, in a vertical position.

The 6-circle diffractometer was designed to be precise and able to hold heavy sample environments (up to 15 kg) and detectors (up to 10 kg). It consists of four axes similar to the 4-circle ones (Komega, Kappa, Kphi, Delta) and two additional axes, mu for the sample and gamma for the detector, allowing the diffraction plane to be horizontal. The 6-circle is equipped with a 3-circle analyzer for high resolution measurements and polarization analysis. Like the 4-circle, all the motors are DC motors driven with Newport XPS controllers. 
The measured angular accuracy of all axes are better than 0.001°. The sphere of confusion is better than 60 µm.

Detectors

The 2-circle and 4-circle diffractometers have their own detection system (respectively a 21-analyzers system and an Agilent 2D CCD detector). Below is a list of other detectors used at CRISTAL, either belonging to the beamline or to the detector pool. The possibility to use a particular detector on a given instrument is symbolized by the colored icons. 

Point detectors

 YAP, CeBr3 scintillators                    CRISTAL : point detectors used for high resolution diffraction     

2D Detectors

Pool: XPAD 3.1, XPAD3.2:

Hyprid pixel detectors developed by SOLEIL, in collaboration with the ESRF CRG BM2 and CPPM. 
Sensor: Si 500 µm/ 560x960 pixels (8 modules of 7 chips each of 80x120 pixels). Pixel size 130x130 µm2, 
Total entrance window surface: 7.28 x 12.48 cm (with blind zones ≈7%). 
XAPD3.2 is gatable for time resolved experiment 

Used for: 
• All diffraction experiments 
• Time-resolved diffraction 


Pool: MAR345 

Image plate detector. 100x100 µm2 pixel size 

Used for : 
• Low resolution powder diffraction experiments 
• High Pressure diffraction

Pool: Rayonix SX165 
 
CCD camera, 165 mm diameter, 40 µm pixel size min. 
4096x4096 pixels 
Pixel size: 40x40 µm2 (min). 

Used for: 
• Crystallographic measurements, 
• Powder diffraction 

CRISTAL/SIXS/GALAXIES beamlines: MAXIPIX 2
  
Purchased in common with SIXS and GALAXIES 
Will be available in Novembre 2012. 

Will be used: 
• Coherent diffraction and ptychography. 

 

Pression

Ambient temperature pressure setup

The sample is a Membrane Diamond Anvil Cell (MDAC), on the Phi stage of the 6-Circle diffractometer. The detector is the MAR345. A laser, located at 90° of the X-ray beam, can be approached to the 90° rotated MDAC, in order to measure the fluorescence of ruby crystals in the DAC. This in situ pressure measurement, allows one to change the pressure without removing the MDAC.

Low temperature pressure setup

The MDAC is located in a specially designed liquid Helium flow cryostat (Tmin=14 K and soon 5 K). Equipped with Kapton windows. The detector is a Rayonix CCD camera. The in situ pressure measurement is the same than the ambient pressure one. The picture shows a pressure measurement, with the laser on.

 

Temperature

Cryostats, gas streamer

Powder diffraction top-loading He-cryostat with rotating capillary (max 2 rps) facing the 2-circle diffractometer (conception R. Steinman, ESRF). 
Temperature range: 4-300 K. 

Closed cycle cryostat (Advanced Research System, ARS DE-302).

This cooling system has been designed to fit the 6-circle diffractometer in order to allow many diffraction configurations. Beamline usage shows that the limitation mainly comes from the He-outlet. This cryostat is used for the diffraction experiments which are not sensitive to vibrations. 
Tmin = 6 K.
ARS HELITRAN liquid helium flow cryostat
placed on the 6-circle diffractometer with the coherent diffraction settings. This cryostat, which has angstrom level vibrations, is well suited for such experiments. Contrarily to the previous displex system, this cryostat is not free to move in any orientation, and should work near the vertical position as shown on the picture. 
Tmin = 4 K

Gas blowers

Hot gas blower (Cyberstar) for powder and single crystals. 

Temperature range 20-900 °C


Gas streamer cooler (N2/He) 
From Cryo Industries of America. Lowest temperature with N2 : 80 K and with He: 30 K. In order to avoid ice formation on the sample, a heated goniometer head is used.

Powder diffraction at low temperature using a gas streamer and a special enclosure. Temperature range: 60K - 300K