• Journal of Sensor Science and Technology
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• v.16 no.1
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• pp.33-38
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• 2007

In this study, one-dimensional fiber-optic radiation sensor with an organic scintillator tip is fabricated to measure high energy X-ray beam profile of CLINAC. According to the energy and field size of X-ray, scintillating light signal from one-dimensional fiber-optic sensor is measured using a photodiode-amplifier system. This sensor has many advantages such as high resolution, real-time measurement and ease calibration over conventional ion chamber and film.

• Structural Engineering and Mechanics
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• v.17 no.3_4
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• pp.347-356
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• 2004

In order to extend the lifetime of buildings and civil infrastructure, patch type fibrous composite retrofitting materials are widely used. Retrofitted concrete columns and beams gain stiffness and strength, but lose toughness and show brittle failure. Usually, the cracks in concrete structures are visible to the naked eye and the status of the structure in the life cycle is estimated through visual inspections. After retrofitting of the structure, crack visibility is blocked by retrofitted composite materials. Therefore, structural monitoring after retrofitting is indispensable and self diagnosis method with optical fiber sensors is very useful. In this paper, we try to detect the peel out effect and find the strain difference between the main structure and retrofitting patch material when they separate from each other. In the experiment, two fiber optic Bragg grating sensors are applied to the main concrete structure and the patching material separately at the same position. The sensors show coincident behaviors at the initial loading, but different behaviors after a certain load. The test results show the possibility of optical fiber sensor monitoring of beam structures retrofitted by the composite patches.

• Korean Journal of Optics and Photonics
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• v.8 no.2
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• pp.161-164
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• 1997

A new hybrid, heterodyne, fiber-optic electric field sensor scheme is presented. In this scheme, a dual polarization, dual frequency, stabilized He-Ne laser is used for the light source of the interferometer, Probe beam is delivered to the sensor head using polarization maintaining fiber. In the sensor head, $LiTaO_3$ electro-optic crystal is used for sensing element. Phase retardation is induced on the dual frquency, dual polarization probe beam due to applied electric field across the crystal. Induced phase retardation is demodulated by in-phase and quadrature demodulation technique. In this way, we can obtain optimum sensitivity for electric field measurement regardless a quasi-static phase difference between two polarization components.

• Journal of Radiation Industry
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• v.8 no.1
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• pp.59-63
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• 2014

Proton Induced X-ray Emission (PIXE) is a MeV ion beam analysis method for use with particle accelerators. PIXE uses low-energy charged particles as an excitation mechanism to generate characteristic x-ray emission from each element in a target. In PIXE analysis, the beam current used is from a few nA to several tens of nA. Chosun University (Cyclotron Research Center) designed a $50{\mu}A$ beam line from the 13 MeV cyclotron for use with a PIXE analysis system, as well as performing beam transport line optimization research. In this study, the beam line operation conditions for the optimization process of beam transport and beam characteristics are shown.

• Proceedings of the Optical Society of Korea Conference
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• 2003.02a
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• pp.322-323
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• 2003

Silicon substrate was fabricated by bulk silicon micromachining and it's structure is based on a proof mass suspended by two beam. To monitor the acceleration, dynamic excitation of accelerometer was performed using a shaker. The attached FFPI and suspension beam are bent because support beam move with variation of the proof mass. Thus phase difference detected by the acceleration change. So we can know that resonance frequency of fabricated accelerometer is about 557 Hz and dynamic range was measured from 0 g to 2 g.

• Proceedings of the Optical Society of Korea Conference
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• 1990.02a
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• pp.34-36
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• 1990

The flow direction in a glass tube is measured by using a forward scatering dual beam laser Doppler velocimeter with an acousto-optic modulator. We can determine the flow direction by measuring the shifted Doppler frequency which is dependent on the order of modulation of the laser frequency shifting moves only the Doppler signal, enabling complete separation of the Pedestal and Doppler singal.

• Proceedings of the KIEE Conference
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• 1993.11a
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• pp.353-355
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• 1993

A single-mode fiber-optic interferometer for measuring small vibrations was constructed. The interferometer is based on the Fabry-Perot configuration that uses a single mode bidirectional fiber coupler as a beam splitter and employs peak detection scheme in the signal processing. The instrument was used to measure the displacement of the translator clamped to a piezo crystal.

• Proceedings of the Optical Society of Korea Conference
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• 1998.08a
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• pp.170-171
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• 1998

Here are proposed the tunable laser for optical memory which uses the acousto-optic deflector. This laser includes the acousto-optic deflector in the Littrow mount configuration so that we may control the beam deflection by means of the induced RF. Consequently, we can achieve the higher speed and accuracy to compare with the Littrow monut configuration only.

• Korean Journal of Optics and Photonics
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• v.2 no.1
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• pp.50-56
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• 1991

This paper describes several optical microphones, "optophone", where a low-power He-Ne laser beam is deflected by a reflecting diaphragm mounted on a photoacoustic cell. A comparision of an acousto-optic detection to a conventional microphone shows comparable sensitivities for the photoacoustic detection. The greatest application of these detections may be found where small volume spectro-phone cells are employed, or where conventional microphones cannot be employed because of high or low temperature or chemical corrosion problems. problems.

• The Korean Journal of Ceramics
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• v.5 no.4
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• pp.409-413
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• 1999

A two-beam polarization (TBP) interfermeter with a reflection configuration for measuring the linear electroptic coefficient is described and investigated experimentally and theoretically. It is shown that a TBP interferometer can be used for measuring the Pockels coefficient of thin film with a strong Fabry-Perot effect. The TBP interferometer technique is used to measure the effective differential linear electro-optic coefficient $re=r_{33}-(n_0/n_0)^3r_{13}$of lead zirconate titanate (PZT) thin film. The results are in agreement with known data.