Beamline

Physical layout of the beamline

The front end, which is common for the two branch lines, includes two beam position monitors and a slit system constructed and feedback controlled in order to keep the photon beam well centred. The first section after the front end also is common and contains a mirror chamber hosting the switching mirrors alternatively delivering the beam to the two branch Lines.

A drawing of the ESCA microscopy beamline after the switching mirrors section is shown in Figure. These sections contain the following components: (i) prefocusing mirror chamber; (ii) monochromator block consisting of entrance and exit slit subchambers and a main chamber, which hosts two gratings and a plane mirror; (iii) connecting elements, water cooling, automatic electropneumatic gate values, and pumping units (ion pumps).

Monitors for pressure (Pirani-Penning and Bayard-Alpert gauges), residual gas (quadruple mass spectrometers), and temperature (thermocouples) are installed at various points on the beamline. As indicated in Fig. 1, retractable diagnostics can be inserted at three different points on the beamline. These diagnostics contain a fluorescence screen (A1,O1 doped with Cr) and a semiconductor photodiode (IRD, AXUV-100). They are used for calibration and characterization of the beamline performance: beam position and photon flux.