Beamline layout

The main optical element of the beamline is represented by a double multilayer monochromator (DMM). Several other optical components like CVD diamond Windows, filters units, slits, beamline diagnostic elements, shutters will complete FAXTOR’s optical layout.

The beamline is divided into two parts, an optical hutch, hosting the DMM and the other optical elements, and the experimental hutch, in which the experiments will be carried out. The sample stage, a 6-axis, will be located at 36 m from the source. 

Source

FaXToR gets its photons from a 2.5 Tesla in-vacuum multipole wiggler (MPW). The main parameters of the MPW source are reported in Table 1, while the expected flux, calculated with SPECTRA is reported in Figure 1. The expected ID photon source size, which plays an important role in phase-contrast applications, along the horizontal direction is < 300 µm. Values are expressed in terms of Full Width at Half Maximum (FWHM).

Optics

The main optical component is a double multilayer monochromator (DMM), consisting of two 500 mm long Si crystals coated with two different stripes, RuC (4 nm) and WB₄C (2.5 nm) to cover the operational energy range [8,50] keV. The energy bandwidth ΔE/E will vary between [1.5, 3.5]%. The beamline will allow users to work with filtered white beams at the end-station whenever higher speeds and/or higher energies are required. The expected operational range with this modality will be [30,70] keV. Five filled racks in the multifilter unit accommodate C, Al, Cu, Ag or Mo filters with different thickness which have been combined in batteries to dissipate the X-ray incoming power. More details on the Optics are listed in Mittone et al 2022 J. Phys.: Conf. Ser. 2380 012035.

Endstation

The main peculiarity of the beamline is in the flexible design of the endstation, hosting two different detection systems which will provide simultaneously high resolution and fast imaging and an auxiliary table for complex sample stage or future beamline upgrade. Combining two of the four cameras available in the FaXToR portfolio, users will tune the experimental configuration according to the special measurements needs. Two indirect detection optics, based on the combination of X-ray scintillation screens and visible optics lens systems are installed on the detection optics table. Their distances with respect to the sample stage can be set remotely. The first microscope in detection system 1 consists of a “White Beam” Triple Magnification Microscope, manufactured by Optique Peter, accommodating three objectives for 2×, 5× and 10×. The detection system 2 is composed by a Low Resolution “White Beam” Macroscope with objectives for 0.476×, 1× and 2.1×, working in tandem mode. Such macroscope has high numerical aperture which makes it prone for high speed imaging.

Four cameras are available, as listed in the table below:

Beam size

The maximum beam size expected at the entrance of the sample is of 35 mm horizontally, while vertically it will range between 5 and 12 mm, according to the energy selected/energy spectrum.

Sample

Sample sizes can vary from a few mm to a few cm.

The tomographic stage will be compatible with custom sample environments allowing performing in-situ/in-operando measurements.

On top of the detection table, an auxiliary platform will be accommodated to allow complex in-situ devices.