Due to the demand to realize shorter wavelength light sources, extreme ultraviolet (EUV) sources and soft x-ray laser (SXRL) are under development. The development of EUV sources at the wavelength of 13.5 nm started to realize light sources to be used for next generation lithography. Xenon was used at the beginning of development, however, to attain higher conversion efficiency, tin is now used as fuel. As a coherent light source, capillary discharge SXRL is under development. After the demonstration of Ne-like Ar SXRL by using electron collisional excitation scheme, the effort to shorten the wavelength has been made by adopting recombination scheme such as H-like N. Though the challenge has not yet been successful, the source has potential to be used as a SXR source in the water window wavelength region. Current status of EUV and SXR sources based on discharge produced plasma will be given.
Current results are described on the research and development of the advanced humanitarian landmine detection system by using a compact discharge-type fusion neutron source called IECF (Inertial-Electrostatic Confinement fusion) devices. With a 50 mm-thick water-jacketed IEC device (IEC20C) of 200 mm inner diameter can have produced 10<sup>7</sup> neutrons/s stably in CW mode for 80 kV and 80 mA. Ample 10.8 MeV γ-rays produced through (n, γ) reaction with nitrogen atoms in the melamine (C<sub>3</sub>H<sub>6</sub>N<sub>6</sub>) powder (explosive simulant) are clearly measured by a BGO-NaI-combined scintillation sensor with distinct difference in case of with/without melamine, indicating identification of the buried landmines feasible.
Extreme-ultraviolet (EUV) lithography is most promising technology for 50 nm technology node which will be used from around the year 2007. There are many issues for realizing EUV lithography, such as developing optical components and radiation sources and one of the most important challenging tasks is to develop an EUV light source. Various technical concepts for realizing high power sources for EUV lithography are under investigation worldwide. Laser produced plasmas (LPP) and discharge produced plasmas (DPP) are the most promising schemes. In general, DPP methods are of special interest, because their prospected costs for the demanded throughput is expected to be much lower than those of LPPs. However, the discharge plasmas are of high risk, because many crucial problems have to be solved before reaching the required power levels. In this work, a high repetitive, compact and low-debris Xe-filled capillary Z-pinch discharge system has been designed and fabricated as an EUV source. We devised an electrode configuration compatible with the system and applied a magnetic switch and a static induction (SI) thyristor stack as a main switch of power modulator.
An experimental and numerical study was conducted on ablation form ns-laser heated aluminum. The goal of present study is to clarify the laser ablation phenomena. In experiments, a YAG laser of 650mJ in 4-7nsec was used to perpendicularly illuminate an aluminum target. Time-resolved measurements were conducted using high-speed camera system. Also, a numerical simulation was conducted using CIP method. The experimental results of time-resolved measurements indicate that the target surface itself is melting until late after the laser irradiation. The SEM pictures of the irradiated indicate that the target surface itself is melting until late after the laser irradiation. The SEM pictures of the irradiated target surface are showing the generation of many minute protrusions. These protrusions near the part that laser is irradiated are facing toward the laser beam path and those of the surroundings are facing toward circumference. It is found by numerical simulation that this is due to the appearance of the critical point just after the laser irradiation. Since the laser beam goes around the critical point, the damaged part expands toward circumference.
A series of experiments were performed to investigate the fundamental characteristics of a KrF laser pumped by electric discharge. The mode patterns of the laser were observed by a high speed camera. A YBCuO target was irradiated by the same laser and the surface conditions were observed by a microscope. A model x-ray source for pre-ionization which used a wire-initiated plasma source was constructed.