• Journal of Powder Materials
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• v.15 no.6
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• pp.466-470
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• 2008

Experiments with a URT-0.5 accelerator (0.5 MeV, 50 ns, 1 kW) generating a nanosecond electron beam for irradiation of silver nitrate in various liquid solutions (water and toluene) were performed with the aim of producing silver nanopowders. A radiochemical reaction allows making weakly agglomerated pure Ag powders with particles of 10-15 nm and 30-50 nm in size by irradiation in toluene and water respectively. The injection of the nanosecond electron beam energy to the solution is optimal. As the absorbed dose increases, the output of the radiochemical reaction does not grow, but more agglomerated powders are synthesized.

• Nuclear Engineering and Technology
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• v.53 no.1
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• pp.266-272
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• 2021

In the pulsed electron beam generators, such as plasma focus devices and linear induction accelerators whose electron pulse width is in the range of nanosecond and less, as well as in cases where there is no direct access to electron beam, like runaway electrons in Tokamaks, measurement of the electron energy spectrum is a technical challenge. In such cases, the indirect measurement of the electron spectrum by using the bremsstrahlung radiation spectrum associated with it, is an appropriate solution. The problem with this method is that the matrix equation between the two spectrums is an ill-conditioned equation, which results in errors of the measured X-ray spectrum to be propagated with a large coefficient in the estimated electron spectrum. In this study, a method based on the neural network and the MCNP code is presented and evaluated to recover the electron spectrum from the X-ray generated by collision of the electron beam with a target. Multilayer perceptron network showed good accuracy in electron spectrum recovery, so that for the X-ray spectrum with errors of 3% and 10%, the network estimated the electron spectrum with an average standard error of 8% and 11%, on all of the energy intervals.

• Korean Journal of Optics and Photonics
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• v.28 no.6
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• pp.356-360
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• 2017

Indium tin oxide (ITO) provides high electrical conductivity and transparency at visible and near-IR wavelengths. ITO is widely used as a transparent electrode for the fabrication of LCDs, OLEDs, and many kinds of optical applications. It is widely employed for electrodes in various electric and display sectors because of its transparency in the visible range and high conductivity. Therefore, one issue is removing a specific area of a layer of material such as ITO or metallic film on a substrate, without affecting the properties of the substrate. ITO-on-glass removal using a laser is friendlier to the environment than traditional methods. In this study, ablation of ITO film on glass using a femtosecond-laser micromachining system (wavelength 1026 nm, pulse duration 150 fs) and a nanosecond-laser micromachining system (wavelength 1027 nm, pulse duration 5 ns) are described, compared, and analyzed.

• Laser Solutions
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• v.5 no.2
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• pp.31-38
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• 2002

This paper describes the process of nanoparticle synthesis by laser ablation of consolidated microparticles. We have generated nanoparticles by high-power pulsed laser ablation of Al, Cu and Ag microparticles using a Q-switched Nd:YAG laser (wavelength 355 nm, FWHM 5 ㎱, fluence 0.8∼2.0 J/㎠). Microparticles of mean diameter 18∼80 ㎛ are ablated in the ambient air The generated nanoparticles are collected on a glass substrate and the size distribution and morphology are examined using a scanning electron microscope and a transmission electron microscope. The effect of laser fluence and collector position on the distribution of particle size is investigated. The dynamics of ablation plume and shock wave is analyzed by monitoring the photoacoustic probe-beam deflection signal. Nanosecond time-resolved images of the ablation process are also obtained by laser flash shadowgraphy. Based on the experimental results, discussions are made on the dynamics of ablation plume.

• Transactions of the Society of Information Storage Systems
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• v.1 no.2
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• pp.127-131
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• 2005

We report a nanometer scale mark formation using a $PtO_x$ thin film or a TbFeCo rare-earth transition metal film and the mechanism. The multi-layer samples($ZnS-SiO_2/PtOx/ZNS-SiO_2,\;ZnS-SiO_2/TbFeCo/ZnS-SiO_2$) were prepared with a magnetron sputtering method on a polycarbonate or a glass substrate. By laser irradiation of approximately a few nanoseconds, nanometer scale marks were fabricated. During the fabrication process, the thin films were thermally reacted or inter-diffused during the laser irradiation. 75 nm bubble marks in the PtOx multi-layer sample by an approximately 4-ns laser irradiation. Inside the bubble mark, Pt particles with a few nanometer sizes are distributed. The $50{\sim}100$ nm bubble marks in the TbFeCo multi-layer sample by a few nanosecond laser irradiations. We will report the detail structure of the samples, the bubble mark formation process and the mechanism.