2017 March 15 - April 24
2017 May 17 - June 29
2017 BTR deadline: 04/17/17
2017 October 11 - December 21
2017 Proposal deadline: 08/01/17
2017 BTR deadline: 09/10/17
|F3 Station Summary|
|Source:||Positron, hard bend magnet source|
|Monochromator:||Water-cooled DCM with options of Si(111), Si(220), and multilayers of 0.6%, 0.22%, 5%, 10% BW|
|Energy:||7 – 30 keV for Si(111)
6 – 20 keV for multilayers
|Focusing:||Sagittal Si(111), mirrors and mono-capillaries|
|Detectors:||Scintillator-coupled Andor camera, Vortex SSD, Maia 384 element detector, Pilatus, Quantum 4, ion chambers|
|Capabilities:||Scanning micro-XRF microscope; Transmission X-ray imaging and tomography; XAFS; X-ray diffraction; oscillation crystallography|
The F3 station is a versatile bend-magnet station that provides a variety of experimental capabilities. The radiation from the 5.3 GeV positrons, 21.6 m upstream from sample, has critical energy of 10.3 keV. The standard monochromator is double-crystal Si(111), tunable from 7 to 31 keV. A sagittal focusing second crystal is available, which focuses about 3 mrad of bending magnet radiation. White-beam and monochromatic mirrors may be used to provide a doubly-focused beam. Alternatively, multilayers with bandpass around 0.6%, 0.22%, 5% and 10% can be used, providing higher flux than Si-111 over an energy range of 5-20 keV. Si(220) crystals can also be used for better energy resolution. CHESS single-bounce mono-capillaries are used for microbeam focusing.
With capillaries focusing, scanning XRF microscope is approaching 10 micrometer spatial resolution. By expending X-ray beam in vertical direction with asymmetric Si(111) crystal, TXM and X-ray tomography has been implemented for large samples with field of view up to 9 mm by 9 mm. X-ray diffraction, X-ray protein crystallography with 0.22% energy bandwidth multilayers are also available. EXAFS and XANES have been implemented in transmission, fluorescence and grazing incident fluorescence mode at F3.
Various detectors and software packages are available for F3 experiments, such as scintillator coupled Andor camera, Quantum-4, Pilatus 200K and 300K, 4-element Vortex SSD and the recently available Maia 384 element detector. Praxes using PyMca libraries and GeoPixe are available for XRF data processing.
Figure 1: F3 experiment hutch, shown in yellow, is surrounded by F1 and F2 hutches, shown in red, and shares the same optics cave, shown in blue, with F2 and F3 beamlines.
Figure 2: A typical setup of scanning XRF microscope. From top-left to bottom-right, the X-rays are confined by a set of ESRF slits and focused by a mono-capillary. The sample is held by a XYZ stage and X-ray focusing is monitored by a far-field viewing camera.