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Beamlines List

BL2B  Photoelectron Spectroscopy of Molecular Solids

  This beamline previously dedicated for experiments in the field of gas phase photoionization and reaction dynamics. Then, thebeamline has been reconstructed for photoelectron spectroscopy of molecular solids with a new end station, and experiments can be performed from May 2014. The monochromator is a spherical grating Dragon type with 18-m focal length.High throughput (1 × 1010 photons s-1) and high resolution (E/ΔE = 2000 - 8000) are achieved simultaneously under the condition of the ring current of 100 mA [1]. The optical system consists of two pre-focusing mirrors, an entrance slit, three spherical gratings (G1 - G3), two folding mirrors, a movable exit slit, and a refocusing mirror [2]. The monochromator is designed to cover the energy range of 23-205 eV with the three gratings: G1 (2400 lines mm-1, R = 18 m) at 80-205 eV; G2 (1200 lines mm-1, R = 18 m) at 40-100 eV; G3 (2400 lines mm-1, R = 9.25 m) at 23-50 eV. The percentage of the second-order light contamination at = 45.6 eV is 23% for G2 or 7% for G3.
  A UHV chamber is placed downstream of the refocusing mirror chamber and equipped silicon photodiode, sapphire plate Au mesh and filters for absolute photon flux measurement, monitor the photon-beam position, relative photon flux measurements and attenuate higher order light, respectively.
  The new end station consists of a main chamber with a hemispherical analyzer (SCIENTA R3000) and a liquid-He-cooled cryostat (temperature range of 15-400 K) with 5-axis stage, a sample preparation chamber with a fast-entry load-lock chamber and a cleaning chamber with LEED, ion gun for sputtering and IR heating unit.
[1] M. Ono, H. Yoshida, H. Hattori and K. Mitsuke, Nucl. Instrum. Meth. Phys. Res. A 467-468 (2001) 577.
[2] H. Yoshida and K. Mitsuke, J. Synchrotron Radiation 5 (1998) 774.

fig1   end station
      Fig. 1. 18 m spherical grating
      monochromator at BL2B.
  Fig. 2. End station of BL2B for photoelectron spectroscopy of molecular solids.

Technical Data

Monochromator 18 m spherical grating Dragon-type
Wavelength Range 23-205 eV
Resolution 2000-8000 depending on the gratings
Experiments Angle-resolved ultraviolet photoemission spectroscopy