ROCK

Storage ring : Toroidal collimating mirror M1 (CINEL/Winlight X)

M1

Collimating principe :

Optical hutch :  Mirrors M2a and M2b harmonic rejection and vertical focusing (IRELECALCEN/Winlight X)

Quick-EXAFS monochromator

Expected flux at the focusing point

The SOLEIL designed Quick-EXAFS monochromators are made of two independent channel-cut crystals (Si(111) and Si(220)) and was first used on SAMBA beamline. Each channel-cut crystal is mounted on a cam driven tilt table allowing it to oscillate periodically with amplitude θ(t) around an average fixed Bragg angle θB. The amplitude can be tune from 0.1 to 4° by an original SOLEIL in vacuum variable cam design. The θB Bragg angle is selected by one of the two goniometers holding the oscillating tilt tables. The 4.5 to 40 keV energy range is available using both Quick-EXAFS monochromators. The channel-cut crystal can be changed by the other one in few seconds during an experiment allowing to record quick-EXAFS data at absorption edges very far in energy. For instance the XAS study of a bimetallic catalyst at both edges during the same catalytic reaction is now possible with the SAMBA’s QuEXAFS set-up, even if the edge energies of those elements are covered by two distinct crystals.

Quick-exafs monochromator

Maximum performance of the Quick-EXAFS mechanics in terms of oscillation frequency of the channel-cut is 40 Hz for two recorded spectra: one with the Bragg angle collection in the downward direction and the other with the Bragg angle collection in the upward direction. Due to the photon flux available at the sample position at the SAMBA beamline in QuEXAFS configuration ((flux ~ 10¹¹ ph/s at 8 keV) the optimal time resolution of experiments on real concentrated and not too absorbing samples is around 100 ms. On ROCK we expect to reach 10¹² ph/s in 50 ms.

(left) Absorption of stacked Cr and Mn metallic foils measured over an amplitude of 3.6 °. Data are the average of 10 spectra each collected at 1Hz. (right) k2 weighted Quick-EXAFS are compared to standard scans taken in almost 15 min.

Related publications:

The SAMBA Quick-EXAFS monochromator: XAS with edge jumping
E. Fonda, A. Rochet, M. Ribbens, S. Belin, L. Barthe, V. Briois
Journal of Synchrotron Radiation (2012), 19, p 417 - 424

 ►Quick-exafs Mode

Crystal type : Si111 Si220 Si311 (4 to 40 keV)
Beam size : from 350 x 79 µm² to 4.9 x 2.2 mm²
Flux ~ 10¹² ph/s at 8 keV

•      Transmission
•      Fluorescence
•      Total electron yield
•      Edge jump

Transmission

Oken ionization chambers

Fluorescence

Avalanche Photo Diode (APD)

TEY

Ni K edge XAS signal (up) collected in a TEY detection mode on a Proton Exchange Membrane Fuel Cell thick film in the Quick-EXAFS mode after correction of glitches. The presented spectrum is not averaged (5s of time acquisition).The frequency of oscillation of the Si(111) channel-cut was 0.1 Hz (5s per spectrum) with an oscillation amplitude of 1.6°.

No picture. The sample must be electrical conductor otherwise a thin layer of graphite may be evaporated. 

Edge Jump

Large energie range from 4 keV (Si111) to 37 keV (Si311) in 30s
The remote selection of the monochromator crystals, Si(111) or Si(311), allowing users to permanently access energies between 4 and 37 keV in Quick-exafs mode. 

E. Fonda, A. Rochet, M. Ribbens, S. Belin, V. Briois The SAMBA quick-EXAFS monochromator: XAS with edge jumping J. Synchrotron Rad. 2012, 19, 417 – 424.

Example of the energy range accessible with Si111 cam=4°

• CombinedTechniques
• Catalysis
• Low temperature
• Liquid Cells
• Energy Science

CombinedTechniques

ROCK's experimental station EXAFS is characterised by a lot of techniques combined to XAS, such as Differential Scanning Calorimetry, Raman Spectroscopy and UV-Visible Spectroscopy.

XAS with Raman spectroscopy Kosi RXN1-785 Kaiser	Iexc. = 785 nm or 532 nm  CCD: 100-3450cm-1 or 200-4000 cm-1  Optical fibers with probehead  Seceral Long Working Distance objectives (150 mm to 35 mm)
XAS with UV-visible spectroscopy Cary 50 VARIAN	With optical fibers 190 < I < 1100 nm VScan < 24000 nm/min XAS cell with mylar or PP windows for optical fiber used in transmission or immersion probe : 2 or 10 mm or cuvettes Quartz, Glass, PMMA, PS
XAS with Raman and UV-Visible spectroscopies
XAS with Differential Scanning Calorimeter (DSC)  DSC 111 Setaram : Calvet type differential scanning calorimeter  -120 to 800°C	* Phase transition (fusion, crystallization, glass transition, polymerization, degradation) *  Cp Evaluation *  Monitoring of reactions (oxidation, reduction, dehydration...)

Catalysis

Retrouvez ci-dessous les différents environnements échantillons catalyseurs à votre disposition sur la station EXAFS.

Polyvalent SOLEIL development for fluorescence, transmission and Raman coupling La Fontaine, C., Barthe, L., Rochet, A., & Briois, V. X-ray absorption spectroscopy and heterogeneous catalysis: Performances at the SOLEIL's SAMBA beamline. Catalysis Today, 2013, 205: 148–158	Two ovens/capillaries set-up collaboration MAX IV/SOLEIL designed by L. Barthe	Characteristics    Lytle-type cell RT 600°C +/- 0.5°C Atmospheric pressure Powdered catalyst gently pressed into the cavity of the sample hoolder (thickness 2, 4 and 6 mm, 0.10 - 0.25 cm3)           Characteristics 2 capillaries oven RT 1000°C +/-0.5°C
High pressure cell for transmission and Raman coupling A. Rochet et al. Catalysis Today (2011) vol 171 186-191  A. Rochet et al. Diamond Light Source Proceedings (2011) 1, e130 1-4		Characteristics  Lytle-type cell RT 600°C +/- 0.5°C 50 bar Powdered catalyst gently pressed into the cavity of the sample holder (thickness 2 mm)
Commercial cell Harrick for fluorescence and Raman coupling C. La Fontaine et al. Harrick Scientific Products (Ed.), Application Note n°91201 (2010).		Characteristics RT 500°C Atmospheric pressure Powdered catalyst (≈50 mg) gently pressed into the sample holder cavity Catalyst pellet (6 mm dia.) disposed onto a BN bed
Gas distribution system		Complex mixtures Saturator for liquid reactants Heated lines (120°C) Patm --> 20 bar Remote control
Mass spectrometer		MKS Cirrus LM99 Analyser Tripple mass filter, 1-200amu or 1-300amu Faraday and SEM detector Maximum operating pressure Faraday 2x10-5 mBar

Low temperature

With the courtesy of SAMBA beamline

Helium Cryostat		He cryostat suitable for transmission and fluorescence detection  (20 K to Room Temperature)
Nitrogen Cryostat		Liquid nitrogen (80 K) cryostat suitable for transmission and fluorescence detection

Liquid Cells

We have different cells with fixed or variable optical path available for basic or acidic solution. Two of them are thermostatically controlled. Note Kapton, Mylar, PP or PTFE can be used as windows depending of the nature of the solution.

Liquid cell with variable optical path for transmission		Thermostated liquid cell (PTFE) with  adjustable optical paths (10 µm to 6 mm)  suitable for the combination of  transmission XAS with UV-Vis spectroscopies (design SPECA)
Liquid cell for transmission		Liquid cells PTFE with fixed optical paths (0.5<o.p.<5mm)
Liquid cell for fluorescence mode		Liquid cell (PCTFE) for fluorescence detection (design F. Villain)
Liquid cell for biological sample		PTFE sample-holder for He cryostat  (two samples ~ 50µl) available for  transmission and fluorescence detection With the courtesy of SAMBA beamline
Thermostated liquid cell		Thermostated liquid cell (PCTFE) with adjustable optical paths (100µm to 10mm) suitable for the combination of transmission XAS with Raman and/or UV-Vis spectroscopies (design F. Villain)     Thermostated liquid cell (PTFE) with adjustable optical paths (10µm to 6mm) suitable for the combination of transmission XAS with UV-Vis spectroscopies (design SPECA)

Energy Science

Setup for Li/Na batteries

	VMP3 Bio-logic Multi-channel Potentiostat  16 independent channels, 6 already equipped (+/-400mA) whose one for impedance measurement
ANR	Electrochemical cell dedicated to operando XAS J. B. Leriche et al. J. Electrochem. Soc., 157, (5) A606-A610 2010
	Multicell support
	Furnace RT to 90°C for 2 electrochemical cells for example
	Thermostated support

EXAFS :                                    

gnuplothowto.pdf (114.69 KB - pdf) (114.69 KB)

Media Folder: 

ROCK

QuickExafs        

quick-exafs_anglais.pdf (1.4 MB - pdf) (1.4 MB)

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ROCK

TBT_cryostats.pdf 

tbt_cryostats.pdf (54.91 KB - pdf) (54.91 KB)

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Media Root