PLÉIADES beamline

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Technical data
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PLÉIADES is an ultra high resolution soft X-ray beamline (ultimate resolving power of about 100000 at 50 eV) covering the energy domain ranging from 10 eV to 1 keV. PLÉIADES is dedicated to spectroscopy based atomic and molecular physics studies of diluted samples (atoms, molecules, ions, clusters, molecules adsorbed on surfaces). All horizontal, vertical and tilted linear polarizations, as well as circular and elliptical polarizations, are available starting from 55 eV thanks to a permanent magnet (80 mm period) Apple II type of undulator. Linear horizontal and vertical polarized beams are available as low as 10 eV from a 2nd (256 mm period) electromagnetic undulator. In the beamline design, particular care has been taken in order to obtain a very high spectral purity soft X-ray beam : thanks to an appropriate combination of quasi-periodic design for the undulators and the use of a varied groove depth (VGD) for the plane grating, higher orders are very efficiently rejected (usually less than 0.5%). A high resolution electron spectrometer, an energy and angle Auger electron - ion coincidence setup (EPICEA), as well as a dedicated station (MAIA) for positive and negative ion photoionization studies (ECR source) are permanently installed on the beamline. Moreover, a conventional laser facility (c.w. and pulsed), as well as the possibility of combining high intensity/high repetition rate (1 mJ/100 kHZ, 5 mJ/20 kHZ, 10 mJ/10 kHZ) femtosecond laser pulses from an in-house facility to the synchrotron beam in pump-probe schemes will also be offered to the users in the near future. The beamline has three optical branches with different focusing properties of the beam. Two of them (branch N°2 and N°3) are offering the external users the possibility of installing their own setups (see table below for spot sizes and beam divergences on sample).
Technical data
Energy range   10 eV - 1000 eV
Resolving power   15000 (10 eV - 40 eV), 20000 - 100000 (35 eV - 1000 eV)
Source   Electromagnetic HU256 (256 mm period) and Apple II permanent magnet HU80 (80 mm period) undulators
Flux @ first optical element   About 1.2·10+15 Photons/s/0.1% BW @ 100 eV
Optics   PGM using varied line spacing (VLS) & varied groove depth (VGD) technologies with no entrance slit
Sample Environment   Differentially pumped gas cell for high resolution electron spectrometer
Continuous measurement of the beam intensity (I0)
ECR ion source
Gas inlet systems for the electron spectrometer and EPICEA coincidence setup
Beam size at sample   50(H)x30(V) µm2 on branch N°2 ; 180(H)x100(V) µm2 on branch N°3
Beam divergence at sample

  9mrad (H) - 4mrad (V) on branch N°2 ; 2mrad (H) - 0.6 mrad (V) on branch N°3
Flux on sample   About 1·10+13 Photons/s/0.1% BW
Detectors   High resolution electron spectrometer, Electron - ion coincidence setup with PSDs
Polarization   10 - 40 eV (linear H, V); 35 - 1000 eV (linear H, V, tilted, elliptical)

Scientific Opportunities
Decay dynamics
of inner-shell excited molecules and clusters
  Interplay between nuclear motion and electronic decay in core-excited species probed by high resolution (sub lifetime) resonant Auger - Raman spectroscopy and Auger - electron ion coincidences
Ultra fast dissociation processes in core-excited molecules and clusters
Role of the soft X-ray inner-shell excitation/ionization in the degradation of biological matter: dissociation dynamics of biomimetic molecules
Dispersed fluorescence spectroscopy of inner-shell excited species
Vector correlations and angular distributions in valence-shell and inner-shell photoionization   Angular distributions of Auger electrons from fixed-in-space molecules

Non-dipole effects studies in the near threshold region of core-excited molecules

Structural investigation of Wan der Waals clusters as extracted from interference effects in the angular distributions of Auger electrons

Vector Correlations in dissociative photoionization of simple molecules induced by K-shell ionization

Inner-shell circular dichroism in the angular distribution (CDAD) of photoelectrons produced by the photoionization of chiral molecules
Multiple photoionization studies of atoms and molecules   Momentum imaging for atoms and diatomic molecules

Spectroscopic studies of multi-electron processes, electronic correlations

Probe of molecular conformations by means of triple-ion-coincidence momentum imaging techniques
Photoionization of ions   Photoionization studies of singly and multiply charged atomic and molecular positive ions

Auto-detachment decay studies of negative ions

Experiments coupling laser and SR beams   Photoionization studies of excited atomic and molecular states using pump-probe experiments
Photo dissociation processes of inner-shell excited molecules studied through a pump-probe arrangement
Photochemistry   Site-selective photochemistry of core-excited molecules

Ion-molecule reactions of doubly-charged ions

Inner-shell spectroscopies of size-selected SiC composite clusters (XAS, XPS, RAS, mass spectrometry)

Chemical reactivity of mixed Van der Waals clusters probed by electron and ion spectrometry

John Bozek
(Head of the group)
Tel:   +33 (0)1 69 35 97 02
Fax : +33 (0)1 69 35 94 56
Christophe Nicolas
(Beamline scientist)
Tel:   +33 (0)1 69 35 96 92
Fax : +33 (0)1 69 35 94 56
Minna Patanen
(Beamline scientist)
Tel:   +33 (0)1 69 35 81 79 
Fax : +33 (0)1 69 35 94 56
Emanuel Robert
(Engineer assistant)
Tel:   +33 (0)1 69 35 96 58
Fax : +33 (0)1 69 35 94 56
Faris Gel'mukhanov
(PALM Guest professor)
2013 - 2016
Tel:   +33 (0)1 69 35 81 54
Fax : +33 (0)1 69 35 94 56
Saikat Nandi
Tel:   +33 (0)1 69 35 90 53
Fax : +33 (0)1 69 35 94 56
Safia Benkoula
(PhD student)
Tel:   +33 (0)1 69 35 81 85 
Fax : +33 (0)1 69 35 94 56
Synchrotron SOLEIL
L'orme des Merisiers
Saint-Aubin - BP48


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 Beamline scientific articles

Preliminary Project

 Beamline description 

 Beamline poster

 News :

- Scientists of the PLEIADES beamline involved in research on radiosensitizing molecules used in cancer therapies

- Einstein-Bohr gedanken experiment performed at the molecular level

- A better decoding of nanoparticle surfaces at the atomic scale

- Addressing experiments and calculation models to improve astrophysical simulations

- « Selfies » of molecules: Structural information of molecules encoded to vibrationally resolved photoelectron cross-sections

- All PLEIADES news


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