Measurement of coherence length and incoherent source size of hard x-ray undulator beamline at Pohang Light Source-II.
We measured the spatial coherence length and incoherent source size of a hard x-ray undulator beamline at Pohang Light Source-II, the stored electron energy of which has been increased from 2.5 GeV to 3 GeV. The coherence length was determined by single-slit measurement of the visibility of the Fresnel diffraction pattern. The correlated incoherent source size was cross-checked for three different optics: the single slit, beryllium parabolic compound refractive lenses, and the Fresnel zone plate. We concluded that the undulator beamline has an effective incoherent source size (FWHM) of 540 μm (horizontal) × 50 μm (vertical).
Department of Physics, POSTECH, Pohang 790-784, South Korea.
So Yeong
SY
Park
Department of Physics, POSTECH, Pohang 790-784, South Korea.
Chung Ki
CK
Hong
Pohang Accelerator Laboratory, POSTECH, Pohang 790-784, South Korea.
Jun
J
Lim