1. Development of Plastic Scintillators with Inorganic Powders Yewon Kim, Hyunjun Yoo, Gyuseong Cho, Minsik Cho, Hyoungtaek Kim, Jongyul Kim, Jun Hyung Bae, Myung Soo Kim, Dong-Uk Kang, Hyunduk Kim Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea E-mail : yewonkim@kaist.ac.kr  Hybrid Scintillator I. Abstract IV. Acknowledgement III. Experimental Results In order to apply the plastic scintillator to the diagnostic X-ray radiography and/or personal dosimeters for the gamma-ray, we developed a plastic scintillator plate based on polystyrene. To overcome the lower light output of the plastic scintillators than inorganic scintillators, we have developed a new hybrid plastic scintillator by blending organic scintillator and inorganic material. The fabricated plastic scintillator is composed of plastic scintillator styrene monomer, PPO, POPOP powders with the mass ratio of 100:1:0.05 and different mass ratio of Gd 2 O 2 S(Tb) powder. To characterize the fabricated 5mm height cylindrical hybrid scintillator covered with teflon reflector, the Cs-137 disc source and the optical fiber coupled spectrometer were used to analyze emission spectrum. Also, PMT was used to measure light output, decay time and the energy resolution. Additionally, the transmittance of each sample is measured using UV-Vis spectrometer.  Light Output  Plastic scintllator + Inorganic Powder -To find optimum ration of inorganic powder(Gd 2 O 2 S(Tb)) in the plastic scintillator, (Gd 2 O 2 S(Tb)) powder is added into the styrene based plastic scintillator with different mass as 0.001g, 0.002g, 0.005g, 0.010g, 0.020g, 0.050g and 0.100g respectively in the 10g of plastic scintillator solution. The bottom and the top of the fabricated samples are cut to make samples have same height of 5mm and the surface of samples is grinded to avoid diffused reflection of the surface using polishing machine.  Transmittance  Decay Time  The decay time measurement of scintillator -The decay time of fabricated scintillator is measured using PMT and FADC400 to find out the difference following the ratio of the Gd 2 O 2 S(Tb) added to plastic scintillator. And the result and the graphs are displayed blow.  Emission Peak  The photo spectroscopy -The intensity of the light is increased following the content ratio of Gd 2 O 2 S(Tb)) in the plastic scintillator. However, there is little difference between 0.01%, 0.02% and 0.00%, reference, of Gd 2 O 2 S(Tb). The hybrid scintillator emits six kinds of major spectra(more than 1000cps) that are 441nm, 491nm, 547nm, 588nm and 623nm and the maximum peak of the spectrum is 547nm and the photo counts is 15226cts at the spectrum.  The macroscopy using a CCD Camera (with 100kVp, 120mAs of X-ray) -The macroscopy about the light output of the fabricated scintillators is performed to find out the increasing light output tendency. As a result, the more Gd 2 O 2 S(Tb) powder is added into the plastic scintillator, the more light is emitted from the scintillator. The amount of photon is decided by the amount of the added Gd 2 O 2 S(Tb) powder.  The absorbance of the scintillators -UV-Visible spectroscopy is performed to measure the absorbance of the fabricated scintillator. Every samples show similar tendency curves between 190nm to 400nm and the range of the absorbance decrease is different above 400nm respectively. The reference plastic scintillator (0% Gd 2 O 2 S(Tb) powder) absorbance most deeply decreases to 0.12 at the 400nm and the range of the other scintillator absorbance is differently decreased according to the ratio of the added Gd 2 O 2 S(Tb) powder. “This work was supported by the Center for Integrated Smart Sensors funded by the Ministry of Education, Science and Technology as Global Frontier Project" (CISS-2012-0006361) Ref.1Ref.20.01%0.02% 0.05% 0.10% 0.20% 0.50%1.00%  The difference between the simulation and measurement -The Simulation is performed to find out the difference between the simulation and the measurement. And the light yield of fabricated scintillator is measured using PMT and FADC400. The comparison between the simulation and the measurement graph and the light yield are displayed blow. GOS:0.001%5445.04 GOS:0.002%5655.11 GOS:0.005%5264.258 GOS:0.010%5969.323 GOS:0.020%5735.12 GOS:0.050%5963.253 GOS:0.100%3851.023