Conceptual Design of Scanning Transmission X-ray Microscopy Endstation at Tps
Hung Wei Shiu1*, Tolek Tyliszczak1, Chia-Hao Chen1, Der-Hsin Wei1, Yao-Jane Hsu1, Way-Faung Pong2, Shangjr Gwo1
1Scientific Research Division, National Synchrotron radiation Research Center, Hsinchu, Taiwan
2Department of Physics, Tamkang University, New Taipei City, Taiwan
* presenting author:Hung Wei Shiu, email:hwshiu@nsrrc.org.tw
STXM is a very useful microscope and most versatile of all synchrotron based microscopes. With this microscopy it not only can strengthen the current users community, but also can broaden the user bases in Taiwan. It was designed ideally to investigate small world in different fields, including material and environmental science, chemical and biological materials, energy materials and magnetism. In this design, STXM endstation is located at the optimized branchline of BL27 in an isolated area. A photon energy covering from 130 to 3000 eV with EPU undulators can satisfy the requirements of different research topics. By using a single toroidal mirror, the monochromatic beam can be focused onto a set of exit slits apertures (H+V) to act as a stable secondary source. The secondary source is focused onto the sample by using a zone plate. The focused beam size (spatial resolution) is defined by the outmost zone width of the zone plate. In our design, a 25 nm outmost zone width zone plate with 240 μm diameter are going to be used for most of the experiments. An order-sort aperture (OSA) is place between the sample and zone plate to suppress higher diffraction orders. With this geometry, the typical working distance A0 (sample to OSA) is ranged from 0.2 mm to 3 mm, depending on the photon energy, size of the OSA and focal length of the zone plate. The sample is scanned perpendicular to the focused beam and the transmitted intensity was recorded by the point detector or CCD detector depending on the operation modes (regular STXM or ptychography). The STXM chamber and all components are UHV compatible, and it can be operated at the pressure up to 1 atm (helium condition).


Keywords: STXM, NEXAFS, Zone Plate, Ptychography