BL4B Varied-Line-Spacing Plane Grating Monochromator for Molecular Soft X-Ray Spectroscopy
Description
The beamline BL4B equipped with a varied-line-spacing plane grating monochromator (VLS-PGM) was constructed for various spectroscopic investigations in a gas phase and/or on solids in the soft X-ray range. Three holographically ruled laminar profile plane gratings with SiO2 substrates are designed to cover the photon energy range from 25 to 1000 eV. The gratings with groove densities of 100, 267, and 800 line/mm cover the spectral ranges of 25 – 100, 60 – 300, and 200 – 1000 eV, respectively, and are interchangeable without breaking the vacuum. Figure 1 shows the absolute photon flux for each grating measured using a Si photodiode (IRD Inc.), with the entrance- and exit-slit openings set at 50 and 50 μm, respectively. The maximum resolving power (E/ΔE) achieved for each grating exceeds 5000. By switching spectrometers at the end station, XAFS, XMCD and ARPES measurements are mainly carried out. Taking advantage of the low photon flux and low electric noise environment, XAFS and ARPES measurements are performed for fragile materials such as organic molecules and polymers.
Fig. 2. Photo of BL4B
Technical Data
| Monochromator | Varied-line-spacing Plane Grating Monochromator |
| Energy Range | 25-1000 eV |
| Resolution | E / ΔE > 5000 (at maximum) |
| Experiments | Soft X-ray spectroscopy (mainly, photoabsorption spectroscopy for solid targets by means of total electron yield method using EM and partial fluorescence yield method using SDD) |
