Yoshiaki Tsunawaki

The development of a 100 MW far-infrared free-electron laser oscillator is reported. By using a 180 MeV electron beam, this system will provide the high power and the rapid scanning of the broad wavelength range. 10-100 mum, to enhance the user programs. The intracavity power of several GWs will be used for Compton back scattering X- or gamma-ray generation. To store such an intense radiation, the dynamics of the FEL oscillator with a coupling parameter mu(c) less than or equal to 1 which is defined as the ratio of the slippage distance and the electron bunch length, was investigated experimentally oil the operating mid-infrared system. (C) 2002 Elsevier Science B.V. All rights reserved.

We are planning a short wavelength FEL experiment combining a micro-wiggler and an X-ray seed pulse. A micro-wiggler makes it possible to lase in the VUV to soft X-ray region using a low-energy electron beam. The development of the micro-wiggler is almost complete. With an intense X-ray seed pulse. quick start-up is expected making the wiggler length short. For the seed X-ray source we will use laser-produced Plasma. The validity of this concert was verified using a simulation code based on the SDE-method. With 10 kW X-ray power for seeding the saturation position is shortened to 5 m. (C) 2000 Published by Elsevier Science B.V. All rights reserved.

Aluminium tri-hydrogen bis (orthophosphate) monohydrate [AlH3(PO4)(2). H2O] is known as a material with a layered structure. We have synthesized the pure single phase of AlH3(PO4)(2). H2O by solvothermal reaction, with high efficiency. it was formed by the reaction of Al(OH)(3) with H3PO4 at 75 wt% : The optimum molar ratio of H3PO4 to Al(OH)(3) is 7.5. The mixture of H3PO4 and Al(OH)(3) in 1-propanol was refluxed at 94 degrees C for 24 hours under stirring. Furthermore, we intercalated phenylphosphonic acid into AlH3(PO4)(2). H2O at room temperature and obtained a material with nano-sized layers (d = 1.52 nm). Measurements of XRD and DTA-TG, and observations of SEM and TEM were made on products.

A hybrid planar wiggler with a period of 20 mm has been studied as the simplest one which gives the strong field including some higher harmonic components by selecting proper sizes of the ferromagnetic and the permanent magnet. Small gap length of the wiggler and small width of permendur satisfy these conditions to a certain degree. Gain analysis of FEL suggests that for high wiggler field of K>1 similar to 1.6, higher harmonic gains are improved primarily due to its strong field, and for low wiggler field of K<1 similar to 1.6, they are mainly due to the modification of the wiggler field distribution.

A hybrid planar wiggler with a period of 20 mm has been studied as the simplest one which gives the strong field including some higher harmonic components by selecting proper sizes of the ferromagnetic and the permanent magnet. Small gap length of the wiggler and small width of permendur satisfy these conditions to a certain degree. Gain analysis of FEL suggests that for high wiggler field of K>1 similar to 1.6, higher harmonic gains are improved primarily due to its strong field, and for low wiggler field of K<1 similar to 1.6, they are mainly due to the modification of the wiggler field distribution.

The photoreduction mechanism of Sm3+ to Sm2+ was studied using a KrF excimer laser. Reduction occurred via a one-photon process (different from previous suggestions). The reduction yield was 0.34 +/- 0.09 in a methanol solution of 18-crown-6 with Sm3+. The oxidized solvent ((CH2OH)-C-. radical) was observed in the transient spectrum. (C) 1997 Elsevier Science S.A.