• Asian-Australasian Journal of Animal Sciences
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• v.17 no.11
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• pp.1608-1614
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• 2004

This study was performed to evaluate the accuracy, validation and applicability of UV spectrophotometer (UV), Ion Chromatography (IC), and Detector tube (DT) methods for measuring ammonia (NH3) concentration in a swine confinement house and swine slurry storage tank. The mean values of $NH_{3}$ emitted from the house and slurry were 5.333 ppm and 42.192 ppm for the IC method; 4.13 ppm and 36.29 ppm for the Detector tube; and 5.417 ppm and 34.193 ppm for the UV method. The accuracy and the correlation of an ammonia level analyzed by the IC method compared to the UV method were 98% and 0.998($R^{2}$) in the swine confinement house and 94% and 0.997($R^{2}$) in the swine slurry storage tank. On the other hand, those of ammonia level measured by the Detector tube compared to the UV method were 77% and 0.957($R^{2}$) in the swine confinement house and 82% and 0.941($R^{2}$) in the swine slurry storage tank. This indicated that the accuracy and the correlation of the IC method compared to the UV method were higher than those of the Detector tube method compared to the UV method. Therefore, it was concluded that the IC method was more accurate in measuring ammonia concentration in a swine house and a swine slurry storage tank. The Detector tube method should not be applied to the swine slurry storage tank in which ammonia concentration is generally higher than 30 ppm because low accuracy is caused by a gross space between scales inscribed in the Detector tube.

• Journal of IKEEE
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• v.21 no.2
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• pp.146-149
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• 2017

In this paper, we propose a wide-range radiation measurement system using GM Tube and NaI(TI) detector. The proposed system is designed as a small module optimized to control and count the detector signal of NaI(Tl) Detector and GM Tube. The radiation dose is measured in a wide-range 0.1uSv/h to 10mSv/h in conjunction with two detectors, and two detectors operate simultaneously at 10uSv/h to 100uSv/h, where the measurement interval overlaps. The radiation dose was selected using a wide-range radiation measurement algorithm that controls the on/off function of the detector in the appropriate interval for the overlapped radiation measurable interval. In order to evaluate the performance of the proposed system, it has been confirmed that the measurement uncertainty of each section is measured as ${\pm}7.5%$ and it operates normally under ${\pm}15%$ of the international standard.

• YAKHAK HOEJI
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• v.22 no.3
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• pp.157-162
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• 1978

Total organic carbon(TOC) can be determined by means of combustion and flame ionization detector. The principle of string method is that a sample acidified to pH2 and transferred into combustion tube by string is oxidized with air. Another combustion tube method is that organic compounds are oxidized in the combustion tube charged with CuO and cobalt asbestos after the acidified sample is injected directly by microsyringe. Carbon dioxide evolved was reduced under specially treated nickel catalyst and hydrogen, the methane produced was detected by flame ionization detector. Linear relationship was found between concentration and the peak height by the string method. The peak area in the case of combustion tube method is in the range of 1-200ppm. The coefficient of variation by string method was 2.3% and that by combustion tube method was 1.8%. The lower detectable limit was about 10mol. Advantages of the latter are simplicity, sensitivity and reproducibility. TOC in contineous stream can also be determined automatically by means of the string method.

• The Journal of the Korea Contents Association
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• v.19 no.4
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• pp.368-380
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• 2019

This study proposes a method to evaluate the performance of a detector by analyzing the dynamic step wedge and histogram according to the change of the tube voltage and sensitivity when using the Automatic Exposure Control (AEC). The performance of a detector was evaluated by measuring X-ray quality, Entrance Surface Dose (ESD), tube current, dynamic range corresponding to detector sensitivities of S200, S400, S800, S1000 per tube voltage of 60, 70, 81, 90 kVp. As a results, all of the qualities satisfied the acceptance criteria, and the Entrance Surface Dose and tube current were decreased stage by stage as sensitivity was set higher. In the dynamic step wedge, the observable dynamic range has also increased as tube voltage became higher. The histogram showed the quantization separation phenomena as the tube voltage was set higher. The higher the sensitivity, the more the underflow and overflow occurred in which the amount of information on both ends of the histogram was lost. In conclusion, the deterioration in the performance of the detector was found to be insufficient to realize the change of the tube voltage and sensitivity when using the Automatic Exposure Control, and it is useful to use dynamic step wedge and histogram in evaluating detector performance evaluation.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.4
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• pp.53-60
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• 2008

Electron detectors used in scanning electron microscope accept electrons emitted from the specimen and convert them to an electrical signal that, after amplification, is used to modulate the gray-level intensities on a cathode ray tube, producing an image of the specimen. Electron detector is one of the key components dominating the performance of scanning electron microscope so that the development of electron detectors having high performance is indispensable to acquire high quality images using scanning electron microscope. In this paper, we designed and manufactured an electron detector and conducted a couple of image capture experiments using it. In particular, scintillator which generates light photons when it is struck by high-energy electrons was manufactured and experimental studies on the optimization of manufacturing condition was carried out. From experiments to evaluate the performance of our detector, it was verified that the performance of our detector is equivalent to or better than that of the conventional one.

• Journal of the Korean Society of Safety
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• v.16 no.1
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• pp.1-8
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• 2001

All objects emit thermal radiation and this radiation is the basis of the techniques used to detect flames. The usual phenomena occurring in the initial stage of the fire are generally invisible products of a combustion and visible smoke. Liquid or gaseous materials do not undergo a smoldering stage so that fires develop very rapidly. Also, the heat generated by the initial flames is usually not sufficient to activate a heat detector. In this case the most effective criterion for automatic fire detection is the flame. According to the fire regulation of korea, the compulsory standard provided that a flame detector shall be installed in a place that the attachment height of detector is higher than 20 m, chemical plants, hangar, refinery, etc.. The results of the research and development are discriminated between a flame and other radiant emitters, developed a UV detector tube contains an inert gas which absorbs UV radiation, developed PZT pyroelectric element is based on the use of photovoltanic cell, developed IR band-pass filter that only allow a 4.3 $\mu\textrm{m}$ radiation wavelength to reach the sensors and developed UV-IR combination flame detector combined into a single detection device.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.5
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• pp.262-266
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• 2013

A new concept of periapical radiography, intra oral x-ray tube and detector system is introduced. It is new system that a miniature x-ray tube is inserted into mouse and it acquired digital image using external detector. In this study, we have investigated temperature and dose distribution of insertional x-ray tube for periapical radiography. To analyze temperature characteristic of x-ray tube, we attached the thermocouple to surface of x-ray tube and we measured the temperature according to distance. Also, we measured the dose distribution of a miniature x-ray tube according to distance. As a result, temperature was constant to $27^{\circ}C$ over 2mm without cooling system, dose distribution of x-ray tube was 3.14 and 1.84mGy in 3 and 5cm, respectively. Therefore, the proposed x-ray system works in lower dose than conventional dental x-ray system. Thus, it is considered that new concept of system will have a significant effect on medical imaging technology.

• KSBB Journal
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• v.24 no.5
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• pp.420-424
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• 2009

The present study was aimed for the fetor in the livestock facilities. Simple detection systems for ammonia and hydrogen sulfide were examined to see the mechanism making the discoloration length of malodorous substance concentration. Detector tube for ammonia showed a good linearity of 99.6% while hydrogen sulfide detector tube gave 99.7% linearity with reproductivity of 95%.

• Progress in Medical Physics
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• v.23 no.4
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• pp.279-284
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• 2012

The X ray has been widely used in both diagnosis and treatment. Recently, a miniature X ray tube has been developed for radiotherapy. The miniature X ray tube is directly inserted into the body irradiated, so that X rays can be guided to a target at various incident angles according to collimator geometry and, thus, minimize patient dose. If such features of the miniature X ray tube can be applied to development of X ray imaging as well as radiation treatment, it is expected to open a new chapter in the field of diagnostic X ray. However, the miniature X ray tube requires an added filter and a collimator for diagnostic purpose because it was designed for radiotherapy. Therefore, a collimator and an added filter were manufactured for the miniature X ray tube, and mounted on. In this study, we evaluated beam characteristics of the miniature X ray tube for diagnostic X ray system and accuracy of measuring the HVL. We used the Si PIN Photodiode type Piranha detector (Piranha, RTI, Sweden) and estimated the HVL of the miniature X ray tube with added filter and without added filter. Through an another measurement using Al filter, we evaluated the accuracy of the HVL obtained from a direct measurement using the automatic HVL calculation function provided by the Piranha detector. As a result, the HVL of the miniature X ray tube was increased around 1.9 times with the added filter mounted on. So we demonstrated that the HVL was suitable for diagnostic X ray system. In the case that the added filter was not mounted on, the HVL obtained from use of the automatic HVL calculation function provided by Piranha detector was 50% higher than the HVL estimated using Al filter. Therefore, the HVL automatic measurement from the Piranha detector cannot be used for the HVL calculation. However, when the added filter was mounted on, the HVL automatic measurement value using the Piranha detector was approximately 15% lower than the estimated value using Al filter. It implies that the HVL automatic measurement can be used to estimate the HVL of the miniature X ray tube with the added filter mounted on without a more complicated measurement method using Al filter. It is expected that the automatic HVL measurement provided by the Piranha detector enables to make kV-X ray characterization easier.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.1 no.1
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• pp.16-28
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• 1991

A study on comparison of standard charcoal tube method, infrared gas analyzer, and detector tube method were conducted. Measurements were performed simultaneously at same sampling points in an air chamber containing benzene, toluene and xylene vapors. Charcoal tube samles were collected at sampling flowrates of 0.05, 0.2, 0.5, and 1.0 1pm. Results are as follows : 1. Coefficients of variation of results with charcoal tube method for bezene, toluene and xylene mixture vapor were 14.34 % in benzene(0.28-11.12 ppm), 9.20 % in toluene (2.68-135.09 ppm) and 10.21 % in xylene (2.56-82.64 ppm), respectively. 2. Results of infrared gas analyzer in mixture air were non-specific on benzene and toluene. Ratio of results of infrared gas analyzer to those of charcoal tube on benzene, toluene and xylene were 696.4 %, 30.3 % and 36.6 %, respectively. 3. Ratio of responses of detector tubes to those of charcoal tube were 49.4 % in benzene, 22.1 % in toluene and 223.9 % in xylene. Xylene detector tube were interfered by toluene greately. 4. Collection efficiencies of charcoal tubes at low concentraton(benzene : 1 ppm, toluene : 10 ppm, xylene : 10 ppm) were stable on various flowrate from 0.05 to 1.0 1pm, but at high concentrations the efficiency decreased at high flowrate above 0.5 1pm. 5. Within the saturation capacity of charcoal, collection effiency decreased at 0.5-1.0 1pm. Smpling feowrates of 0.05-0.20 1pm were appropriate for sampling organic vapors.