Double crystal monochromator

SI(220) double crystal monochromator was used with entrance slit (1 mm high 20 m from the source point) chosen to give a bandpass of 2 eV at the Pt edge, 11,563.7 eV.( ) The operation of the catalyst... 

The typical experimental setup (here the experiment established at beamline G3/ HASYLAB [12] is shown) is outlined in Figure 5. The white synchrotron radiation is monochromatized by a double crystal monochromator using the Ge (311) reflection... 

X-ray Instrumentation. All experiments were performed at the Cornell High Energy Synchrotron Source (CHESS) operated at 5.8 GeV (Stations A-3, B and C-2). Monochromatic radiation was obtained with a Si (220) double crystal monochromator. In order to eliminate higher harmonics, 50% detunning was typically employed. ... 

FIGURE 2.22 Bragg reflections from a double-crystal monochromator. From the Bragg equation, nX=2ds,m6, t/for the planes of the crystal stays constant, so changing the angle changes the wavelength of the X-rays reflected. 

X-ray absorption spectroscopic measurements were carried out at the storage ring DORIS III (HASYLAB DESY, Hamburg, Germany) at the EXAFS II beam line, which was equipped with a Si (111) double-crystal monochromator. All spectra were recorded at room temperature in a step-scanning mode. For data analyses the program WinXAS [17] was used. 

EXAFS data (Rh K-edge ((23220 eV) or Ir Lm-edge (13419 eV)) were collected in transmission mode on station 9.2 of the Daresbury Synchrotron Radiation Source, operating at 2 GeV with an average current of 150 mA. A water-cooled Si(220) double crystal monochromator was used, with its angle calibrated by running an edge scan of a 5 pm Rh or Ir foil. For each sample 2-10 scans were recorded at room temperature in the... 

ASAXS experiments were conducted on Beamline II-2 at the Stanford Synchrotron Radiation Laboratory (SSRL). X-ray energies 5 and 100 eV below the measured K edge for Ni in the ionomer (8333 eV in Ni metal) were selected by a double-crystal monochromator using planar Sl(lll) crystals with a nominal resolution of zH eV. The scattering apparatus has been described in detail else rtiere[35,36]. The data were corrected for transmittance of the sample and fluctuations in Incident beam Intensity and are shown herein on a consistent relative intensity scale. 

Photon beam position monitors are essential to ensure that after an injection the electron beam position is adjusted to allow the SR to strike the beam line optical components in a constant way. The wavelength output from a double crystal monochromator is especially sensitive to the vertical beam position. Also, the quality of the focus, from a toroid mirror, is especially sensitive to the horizontal beam position (figures 5.18(c) and (e)). On existing machines it is necessary to recalibrate the wavelength and the focussing of a beam line optical system after each injection. 

Figure 5.10 Incorporating line focussing into the (+,—) double crystal monochromator. From Bordas (1982) with permission.

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