@misc{oai:repo.qst.go.jp:00081027,
 author = {Wada, Ken and Shirasawa, Tetsuroh and Mochizuki, Izumi and Maekawa, Masaki and Kawasuso, Atsuo and Hyodo, Toshio and Wada, Ken and Maekawa, Masaki and Kawasuso, Atsuo},
 month = {Nov},
 note = {Low-energy electron diffraction (LEED) is a well-established technique for structural analysis of crystal surfaces. However, in the case of surfaces containing heavy elements, complex multiple scattering makes it difficult to analyze. Low-energy positron diffraction (LEPD), the positron version of LEED, has been predicted by theorists to be an ideal surface structure analysis method to solve the difficulties of LEED because it shows less-multiple scattering than LEED and simple scattering factors similar to those of X-ray diffraction [1].
We developed a LEPD experimental system using a high-intensity slow-positron beam generated by an electron linear accelerator (linac), and successfully observed LEPD pattern from Ge(001)-2×1 structure [2]. Due to the characteristics of the detector, however, the experimental efficiency is poor because of the existence of a cross-shaped dead area. 
To observe diffraction patterns without the cross-shaped dead area, we are developing “HEX-LEED/LEPD” system consisting of a set of a three-layer delay-line anode detector (also called a Hexanode from its appearance) and microchannel plates (MCPs) [3] with a center hole in collaboration with the developer of the detector (RoentDek) and the manufacturer of LEED equipment (OCI). We have successfully observed LEED patterns without the cross-shaped dead area by using the HEX-LEED/LEPD system developed., 4th QST International Symposium -Innovation from Quantum Materials Science-},
 title = {DEVELOPMENT OF A LOW-ENERGY POSITRON DIFFRACTION APPARATUS WITH A THREE-LAYER DELAY-LINE ANODE DETECTOR},
 year = {2020}
}