@article{334aabfebd694c26b3e41ee0181e030c,
title = "Soft x-ray laser beamline for surface processing and damage studies",
abstract = "We have developed a soft x-ray laser (SXRL) beamline equipped with an intensity monitor dedicated to ablation study such as surface processing and damage formation. The SXRL beam having a wavelength of 13.9 nm, pulse width of 7 ps, and pulse energy of around 200 nJ is generated from Ag plasma mediums using an oscillator-amplifier configuration. The SXRL beam is focused onto the sample surface by the Mo/Si multilayer coated spherical mirror. To get the correct irradiation energy/fluence, an intensity monitor composed of a Mo/Si multilayer beam splitter and an x-ray charge-coupled device camera has been installed in the beamline. The Mo/Si multilayer beam splitter has a large polarization dependence in the reflectivity around the incident angle of 45◦. However, by evaluating the relationship between reflectivity and transmittance of the beam splitter appropriately, the irradiation energy onto the sample surface can be derived from the energy acquired by the intensity monitor. This SXRL beamline is available to not only the ablation phenomena but also the performance evaluation of soft x-ray optics and resists.",
author = "Masahiko Ishino and Dinh, {Thanh Hung} and Yuji Hosaka and Noboru Hasegawa and Kimio Yoshimura and Hiroki Yamamoto and Tadashi Hatano and Takeshi Higashiguchi and Kazuyuki Sakaue and Satoshi Ichimaru and Masatoshi Hatayama and Akira Sasaki and Masakazu Washio and Masaharu Nishikino and Yasunari Maekawa",
note = "Funding Information: Japan Society for the Promotion of Science (JP19K15402, P16019); Quantum Leap Flagship Program (JPMXS0118067246,JPMXS0118070187). Funding Information: Acknowledgment. The authors thank Dr. H. Hara and H. Kawasaki of Utsunomiya University for their contributions to the beamline construction. The authors are also deeply indebted to Y. Ono, T. Gisuji, T. Tamura, Y. Shimada, Y. Nakamura, and K. Maeda of Utsunomiya University for useful technical support. Measurements of the transmittances of Zr filters, the sensitivity of the x-ray CCD camera, and the efficiency of the Mo/Si multilayer beam splitter were performed under the approval of the Photon Factory Program Advisory Committee (Proposal Nos. 2015G667 and 2017G638). One of the authors (T.-H. D) acknowledges support from a JSPS Postdoctoral Fellowship for Overseas Researchers (No. P16019), and JSPS KAKENHI Grant Number JP19K15402. Part of this work is supported by the Quantum Leap Flagship Program of the Ministry of Education, Culture, Sports, Science and Technology of Japan (MEXT Q-LEAP, Grant Nos. JPMXS0118067246 and JPMXS0118070187). Publisher Copyright: {\textcopyright} 2020 Optical Society of America.",
year = "2020",
month = apr,
day = "20",
doi = "10.1364/AO.387792",
language = "English",
volume = "59",
pages = "3692--3698",
journal = "Applied Optics",
issn = "1559-128X",
publisher = "Optica Publishing Group",
number = "12",
}