Beamline Description

Photon flux and Resolving power

The experimental photon flux through the beamline has been measured using a removable AXUV-100 photodiode, located between the refocusing mirror and the end station (see Figure 1). The typical quantum efficiency of the photodiode has been taken into account. With slits of 300 µm width and with 200 mA electron current accumulated in the storage ring, the maximum photon flux, reached at 9 eV in first harmonic, is more than 5x1012 photons/s, while at 6.5 eV and 11 eV it decreases to about 1x1012 photons/s. For the SiC grating, the maximum photon flux of more than 3x1011 photons/s is reached at about 20 eV. For the Pt grating, available since March 2009, the maximum photon flux, reached at 23 eV, is more than 1x1012 photons/s, while at 19 and 35 eV it decreases to about 3x1011 photons/s.

In the above conditions the calculated total resolving power (E/DE) of the beamline is 2850 at 9 eV, 2570 at 20 eV, and 1670 at 31 eV of photon energy but it can be improved, by closing the slits, up to about 50000. The calculated resolving power (E/DE) of the monochromator is shown in Figure 2 for a complete open entrance slit and exit slit widths of 10 (top curves), 20, 50, 100, and 300 µm (bottom curves).

                              Fig.1: Photon flux of the BaDElPh beamline                                      Fig.2: Calculated resolving power (E/DE) of the BaDElPh NIM

Last Updated on Monday, 15 January 2018 18:05