Beamline I3 - Short information
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This is an undulator beamline for the low energy region (5 - 50 eV). It is equipped with a normal incidence monochromator with very high energy resolution (resolving power greater than 105). The undulator is of the "apple-type" providing variable polarization. There are two branch-lines to accommodate several different end-stations. One branch-line is used for photoelectron spectroscopy on solids using an experimental station for high resolution angle resolved photoemission, including spin detection. An on-line III-V MBE system is also available. A second branch-line is equipped with a differential pumping stage to allow for gas phase measurements and it is constructed for easy exchange of end-stations. Its main use is for atomic and molecular spectroscopy and luminescence measurements.
Contact persons:
Balasubramanian Thiagarajan, beamline manager
Mats Leandersson
Technical data:
| Source |
Elliptically polarized undulator. |
| Pre-focusing optics |
A combination of a spherical, a plane, and a plane elliptical mirror focuses the radiation from the undulator onto the entrance slit in the vertical direction and on the spherical grating in the horizontal direction. |
| Monochromator |
A 6.65m off-axis eagle type normal incidence with three gratings. MgF2/Al coated grating for photon energies from 5 to 11eV, 4300 lines/mm SiC coated grating for energies from 11 to 26 eV, 4300 lines/mm Pt coated grating for photon energies above 26 eV. |
| Energy range |
5 - 50 eV. |
| Energy resolution |
E/dE ~ 1x105. |
| Re-focusing optics |
A plane mirror to compensate the motion of the beam in the horizontal plane when changing the photon energy. The compensating mirror is also used for flipping the beam between the two branch lines. The solid state branch uses two KB mounted plane elliptical mirrors for refocusing. The second branch line uses a toroidal mirror. |
| Photon flux on sample |
1011 - 1013 ph/s/0.1%bw for 100 mA stored current. |
| Spot size on sample |
0.2mm (V) x 0.3mm (H) at the solid state end station and 0.3mm (V)) x 0.5mm (H) at the gas phase/luminescence end station. |
| Experimental station |
Solid state end station: Scienta 200mm R-4000 hemispherical electron analyser with MCD as well as a spin detector for angle, energy and spin resolved photoemission. The analyzer can be rotated ± 130° around the beam axis (i.e., along the energy dispersing direction of the analyzer). The analyzer is mounted such that the angular dispersion plane is along the beam axis. The manipulator can be rotated in the energy dispersing direction. Sample preparation, molecular beam epitaxy, and load lock chambers. Sample cleaning & heating stages, sample transfer system, sample characterization by e.g. LEED, RHEED and Auger.
Gas-phase/luminescence branch: End stations provided by user groups. |
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