The characteristics and purposes of synchrotron-based microscopies, such as transmission X-ray microscopy (TXM), scanning photoelectron microscopy (SPEM) and photoelectron emission microscopy (PEEM), are described as follows:
Transmission X-ray microscopy
Transmission X-ray microscopy is proved to be an
efficient instrument in medical diagnostic and interior three dimensional
structure of nano-material owing to its large penetration depth and superior
spatial resolution. The TXM at beamline BL01B(1,2) of the Taiwan Light Source (TLS) provides two-dimensional
imaging and three-dimensional tomography at energy 8-11 keV with a spatial
resolution of 50-60 nm, and with the Zernike-phase contrast capability for
imaging light materials such as biological specimen. TXM allows aqueous
specimen due to no vacuum requirement.
Scanning photoelectron microscopy
Scanning photoelectron microscopy is a microscope
which utilizes photoelectron spectroscopy to form the microscopical images and
equipped with an undulator light source, a zone plate optic system, a
nano-positioning sample stage, and a hemispherical electron analyzer with
multichannel plate. By raster-scanning the sample with respect to the focused
photon beam and synchronized collecting the photoelectrons emitted from the
illuminated micro-spot, a two dimensional distribution of photoelectron
intensity can be constructed. It provides a spatial resolution of about 0.15 μm
and an energy resolution of better than 0.25 eV.
Photoelectron emission microscopy
Photoelectron emission microscopy is based on the
imaging principle similar to optical microscopy. When a beam of synchrotron X
rays is focused on a sample, the material emits electrons whose energy and
trajectory convey a great deal of information. PEEMs collect and focus these
electrons with a system of magnetic and electrostatic lenses. The resulting
image provides the information of surface chemical reactions and magnetic
structures of the sample.