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Nishimura, Akihiko; Terada, Takaya
Proceedings of SPIE, Vol.8963 (CD-ROM), p.896307_1 - 896307_7, 2014/02
Times Cited Count：0 Percentile：0(Optics)We proposed FBG sensor made by femtosecond laser processing could be the best candidate. Combination with fabric reinforcement and heatproof adhesive mold protected fragile optical fiber. To make the best use, we fixed the FBG sensor by metal mold. A groove was processed to a SUS metal plate with a grindstone. We used a Quasi-CW laser to weld a filler wire on plate. The optical fiber set under the filler wire beforehand was heated by the laser pluses with 10 J and 10 ms, partially to be soaked in a weld pool. A series of weld pool formed a sealing clad on the groove. The FBG sensor was buried at 2 mm depth over the length of 1 cm. No degradation on its reflection spectra was detected before and after the processing. The FBG sensor can detect the vibration of the plate caused by impact shocks. In this paper, Bragg peak shift of the FBG sensor under laser cladding condition has been discussed.
Ito, Fuyumi; Nishimura, Akihiko
no journal, ,
A new probing system has developed to be applicable in severe accidents of Fukushima BWRs. This probing system has an optical coupling device and a water proof scope. First, the optical fiber coupling device for maintenance was developed. It has two functions such as endoscope observation and laser induced breakdown spectroscopy in its very compact body. These functions can be operated remotely via a composite-type optical fiber. The optical fiber scope enables both laser energy delivery and target image transmission. Secondly, the waterproof scope was newly added to this compact device. It consisted of a wide-angle lens and a contraction optical system and an image fiber and so on. This scope can observe the entire situation from a long distance under water and atmosphere. This scope would permit wide-angle image and laser processing at the underwater condition with low transparency.
Terada, Takaya; Yamada, Tomonori; Nishimura, Akihiko
no journal, ,
Morita, Toshimasa
no journal, ,
Proton acceleration by using a 620TW, 18J laser pulse of peak intensity of 5
10
W/cm
irradiating a disk target is examined using three-dimensional particle-in-cell simulations. It is shown that protons are accelerated efficiently to high energy for a "light" material in the target. In addition, using the best conditions for the target, one can generate a proton beam with an energy of 200 MeV.
