• Proceedings of the Korean Society of Medical Physics Conference
• /
• 2006.08a
• /
• pp.102-102
• /
• 2006

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

• Journal of Sensor Science and Technology
• /
• v.20 no.2
• /
• pp.96-101
• /
• 2011

In this study, we fabricated a fiber-optic phantom dosimeter by arraying square type of plastic optical fibers in a PMMA phantom for measuring relative depth doses of therapeutic photon beams. To minimize the cross-talk between fiber-optic dosimeters, we selected appropriate septum by measuring leaked scintillating lights according to the various kinds of septa. In addition, we measured percentage depth doses of 6, 15 MV photon beams using a fiber-optic phantom dosimeter.

• Journal of Sensor Science and Technology
• /
• v.17 no.6
• /
• pp.462-469
• /
• 2008

In this study, we have fabricated a fiber-optic radiation sensor using an organic scintillator and plastic optical fiber for brachytherapy dosimetry. Also, we have measured relative depth dose rates of Ir-192 source using a fiber-optic sensor and compared them with the results obtained using a conventional EBT film. Cerenkov lights which can be a noise in measuring scintillating light with a fiber-optic sensor are measured and eliminated by using of a background optical fiber. It is expected that a fiber-optic radiation sensor can be used in brachytherapy dosimetry due to its advantages such as a low cost, simple usage and a small volume.

• Journal of Sensor Science and Technology
• /
• v.18 no.2
• /
• pp.173-178
• /
• 2009

In this study, we have fabricated a fiber-optic dosimeter using an organic scintillator and a plastic optical fiber for measuring percentage depth dose with high energy X-ray beam. The scintillating light generated in organic sensor probe embedded in a solid water are guided by 20 m plastic optical fiber to the light-measuring device such as a photodiode- amplifier system. Using a fiber-optic dosimeter and an ion chamber, percentage depth dose curves are measured with 6 and 15 MV energies of X-ray beam whose field sizes are $2\;cm\;{\times}\;2\;cm$ and $10\;cm\;{\times}\;10\;cm$.

• Korean Journal of Optics and Photonics
• /
• v.21 no.1
• /
• pp.16-20
• /
• 2010

In this study, we have fabricated a fiber-optic dosimeter using an organic scintillator and a plastic optical fiber. The dosimeter measure skin dose and percentage depth dose in a build-up region for an incident high energy photon beam. The scintillating light generated in the organic sensor probe embedded in a solid water phantom is guided by 30 m plastic optical fiber to a light-measuring device such as a PMT or an electrometer. In addition, using a fiber-optic dosimeter or a GAFCHROMIC EBT film, skin dose and percentage depth dose in the build-up region are measured and compared.

• Journal of Sensor Science and Technology
• /
• v.23 no.4
• /
• pp.245-250
• /
• 2014

When the charged particle travels in transparent medium with a velocity greater than that of light in the same medium, the electromagnetic field close to the particle polarizes the medium along its path, and then the electrons in the atoms follow the waveform of the pulse which is called as Cerenkov light or radiation. This type of radiation can be easily observed in a spent fuel storage pit. In optical fibers, the Cerenkov light also can be generated due to their dielectric components. Accordingly, the radiation-induced light signals can be obtained using optical fibers without any scintillating material. In this study, to measure the intensities of Cerenkov radiation induced by gamma-rays, we have fabricated the fiber-optic Cerenkov radiation sensor system using silica optical fibers, plastic optical fibers, multi-anode photomultiplier tubes, simulated spent fuel assembly and a scanning system. To characterize the Cerenkov radiation generated in optical fibers, the intensities of Cerenkov radiation generated in the silica and plastic optical fibers were measured. Also, we measured the longitudinal distribution of gamma rays emitted from the Ir-192 isotope by using the fiber-optic Cerenkov radiation sensor system and simulated spent fuel assembly.

• Journal of Sensor Science and Technology
• /
• v.18 no.5
• /
• pp.402-407
• /
• 2009

In this study, plastic optical fiber sensors which can measure thermal neutron dose in a mixed neutron-gamma field are developed and characterized. Using $^{252}Cf$ and $^{60}Co$ sources, the scintillators suitable for thermal neutron detection, are tested and the scintillating lights generated from a plastic optical fiber sensor in the Kyoto University Critical Assembly (kuca) core are measured. Also, the distributions of thermal neutron and gamma-ray are measured in a mixed field as a function of the distance from the center of the reactor core at KUCA and the distribution of thermal neutron is obtained using a subtraction method. Sensitivity of the fiber-optic radiation sensor system is about 0.49 V/mW according to power of the KUCA core and its relative error is about 1.2 %.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.63 no.2
• /
• pp.284-290
• /
• 2014

A fiber-optic beta/gamma dual detector system with two types of sensing probes was fabricated to detect the beta- and gamma-rays simultaneously. As scintillators of the sensing probe type 1, two different inorganic scintillators, $CaF_2(Eu)$ and LYSO(Ce) crystals, were used to obtain the each scintillating efficiency with respect to beta-and gamma-rays and the inherent energy spectra of radioactive isotopes. In the case of the sensing probe type 2, which is composed of two identical inorganic scintillators and a beta shielding material based on the lead, it could discriminate beta- and gamma-rays using a subtraction method. In conclusion, we demonstrated that the proposed fiber-optic beta/gamma dual detector could measure and discriminate beta- and gamma-rays using both energy spectroscopy and subtraction method.

• Korean Journal of Optics and Photonics
• /
• v.20 no.4
• /
• pp.201-206
• /
• 2009

In this study, we have fabricated a fiber-optic radiation sensor for detection of tritium using inorganic scintillators and optical fibers. We have tested various kinds of inorganic scintillators such as $Gd_2O_2S$ : Tb, $Y_3Al_5O_{12}$ : Ce, and CsI : Tl to select the most effective sensor tip. In addition, we have measured the scintillating lights using a photomultiplier tube as a function of distance between sensor tips to the source with the different activities of hydride tritium. The final results are compared with those which are obtained using a surface activity monitor.