BL-11D characterization of optical elements used in the VSX region

Kazuhiko Mase
6107 (PHS: 4440)

1. Introduction

BL-11D has been designed for photoelectron spectroscopy of solid and solid surfaces in the vacuum ultraviolet (VUV) and soft X-ray (SX) region. However, since the photoelectron spectrometer was moved to a newly constructed undulator beamline, BL-11D has been equipped with a reflectometer to characterize optical elements in the VUV and SX regions. A varied-deviation angle-type monochromator can provide a wide range of photon energy with one grating in addition to small intensity of higher order lights. Such monochromator was adopted at BL-11D. The optical layout of BL-11D and the detailed mechanism of photon energy scanning are shown in Figs. 1 and 2, respectively. The wide photon energy range is covered by two gratings, G1 (300-80 eV) and G3 (60-240 eV) with a groove density of 2400 lines/mm.

Fig. 1 optical layout of BL-11D beamline. The distances from the source point are shown in meter.


Fig. 2 schematics of BL-11 Mp-G mechanism

2. beamline performance

OpticsEntrance slit{focusing mirrors{plane mirror{spherical grating{exit slit
Photon energy 200`900eV (G1), 60`245eV (G3)
Photon resolution E/Δ E~ 2000 (G3, Slits 200 μm~100 μm)
Beam size 1 mm (H)×0.1 mm (V)
Flux max 1011 photons/seciSlits 200 μm~100 μm at 100eV, 400 mAj

3. Reflectometer

Fig. 3 shows schematic of the reflectometer equipped at BL-11D for the measurements of reflectivities of gratings and optical mirrors.
  1. The incidence angle varies between 5 and 89 degree.
  2. The arm length of the detector rotation is 200 mm so that angular resolution <0.1°in reflectivity measurements can be obtained with narrow slits and small apertures.
  3. A sample of 200 mmφ can be mounted on the sample stage.
  4. The ultimate vacuum of the reflectometer chamber is 1x10-5 Pa. With two turbo-molecular pumps of 800 liters/s, it takes 5-6 hours to be ready for the measurements after starting pumping.
  5. For further information, please contact the beamline manager.

4. Reference

[1] Photon Factory activity Report 1997 #15 (1997) A101.

Last modified : 2013-04-18