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Volume 40 (2005)
- Issue 4 Pages 306-
- Issue 3 Pages 242-
- Issue 2 Pages 128-
- Issue 1 Pages 2-
Volume 40, Issue 2
Displaying 1-7 of 7 articles from this issue
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Fumihiro SAITO, Shinya FURUICHI, Naureen M. RAHMAN, Takao IIDA, Jun KO ...2005 Volume 40 Issue 2 Pages 128
Published: 2005
Released on J-STAGE: August 05, 2010
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Hiroshi YASUDA, Norimichi JUTO, Ikuo KOBAYASHI, Hiroko OHUCHI2005 Volume 40 Issue 2 Pages 157-165
Published: 2005
Released on J-STAGE: August 05, 2010
JOURNAL FREE ACCESSSome materials can keep the energy of ionizing radiations in metastable condition and release it when being exposed to UV radiation or visible light. Dosimeters composed of such materials are generally called “photoluminescence dosimeter (PLD)” and selected PLDs are now widely used for individual monitoring and measurements in other situations, in place of the conventional dosimeters such as film badges and thermoluminescence dosimeters (TLDs). In this report, the major characteristics and the state of representative three PLDs (fluorescence glass dosimeter, alumina OSL dosimeter and imaging plate) are introduced and also new expected phases of their use are discussed.View full abstractDownload PDF (8241K) -
Noriyuki OUCHI2005 Volume 40 Issue 2 Pages 166-169
Published: 2005
Released on J-STAGE: August 05, 2010
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Jung-Hua CHANG, Pin-Chieh HSU, Jiunn-Hsing CHAO, Pao-Shan WENG, Jenn-L ...2005 Volume 40 Issue 2 Pages 170-176
Published: 2005
Released on J-STAGE: August 05, 2010
JOURNAL FREE ACCESSDigital kVp meter, ion chamber, and x-ray films were used to study the tube voltage, beam output, and dose distribution for 29 x-ray units. Of which 14 units are equipped with single phase power supply and 15 with inverter frequency power supply. The experimental results show that the dose is dependent on tube voltage, tube current, field size except beyond 20×20cm2, exposure distance, and heel effect. The relationship between dose and tube voltage and exposure distance as well is non-linear, while that between dose and tube current is linear. The non-uniform and non-symmetric dose distribution depends on the heel effect of the x-ray beam. The measured voltage deviating from the default value may reach -2.4% to -9.1% depending on the power supply system used. The dose delivered from the units with inverter frequency power supply is 1.64 times higher than that with single phase power supply.View full abstractDownload PDF (1807K) -
Fumihiro SAITO, Shinya FURUICHI, Naureen M. RARMAN, Takao IIDA, Jun KO ...2005 Volume 40 Issue 2 Pages 177-182
Published: 2005
Released on J-STAGE: August 05, 2010
JOURNAL FREE ACCESSA new method was developed for measuring particle size distribution of radon decay products. Aerosols of radon decay products were collected on the filters set on stages at a low pressure cascade impactor, and then alpha particles from those were detected by an imaging plate (IP) which has a high spatial resolution and a high sensitivity. Incident alpha particles were observed as a graphic image on the IP. The activity of radon decay products was estimated using the newly developed alpha spot counting program. The size distributions of aerosols of radon decay products were measured with this method in Kyoto University Research Reactor Institute (KURRI) and National Institute of Radiological Sciences (NIRS). The validity of the measuring technique using an IP was confirmed by comparing with the result using ZnS (Ag) scintillation counters.View full abstractDownload PDF (3974K) -
Shinji TOKONAMI, Yuu ISHIMORI, Tetsuo ISHIKAWA, Keizo YAMASAKI, Yuji Y ...2005 Volume 40 Issue 2 Pages 183-190
Published: 2005
Released on J-STAGE: August 05, 2010
JOURNAL FREE ACCESSAn intercomparison exercise of radon, radon decay products and particle size distribution was carried out using the radon/aerosol chamber at National Institute of Radiological Sciences, 2002. Nine institutions participated in this exercise. Radon concentrations were first compared using a domestic ionization chamber, which was regarded as the primary standard equipment in Japan. Subsequently, several types of passive radon detectors were placed in the radon/aerosol chamber and their readings were compared with each other. Radon decay products concentrations were also intercompared, though the number of participants was small. After injection of Carnauba wax aerosols with the evaporation-condensation method, the particle size distribution of radon progeny was compared with three different sampling techniques: graded screen array, diffusion battery and cascade impactor. The present paper describes an overview of the experiment and the present status of correspondence on radon devices.View full abstractDownload PDF (3460K) -
Shymal Ranjan CHAKRABORTY, Abdus Sattar MOLLAH, Aleya BEGUM, Gias Uddi ...2005 Volume 40 Issue 2 Pages 191-201
Published: 2005
Released on J-STAGE: August 05, 2010
JOURNAL FREE ACCESSThe activity concentration levels of 232Th, 238U, 40K and 137Cs in drinking water of different locations of Bangladesh were measured by using a high purity germanium (HPGe) detector. The average activity levels with one standard deviation (1σ) of 232Th, 238U and 40K were found to be 250±52mBq/L-1, 157±30mBq/L-1 and 9±3Bq/L-1, respectively. The 137Cs was detected only in 32% samples with an average 4±0.8Bq/L-1. A good correlation between the activities of 232Th and 238U was found. The radium equivalent activity (Raeq) and the representative level index (Iγr) due to natural radionuclides were also calculated. The average Raeq was found to be 1, 212±303mBq/L-1 and the average Iγr was found to be 10±3mBq/L-1. The annual individual committed effective dose (HE) due to intake of radionuclides in water was also evaluated and the average value was found to be 74±21μSv. The distribution of radionuclides was found to be normal except 137Cs. The radioactivity levels of these radionuclides were comparable to the corresponding reported values of drinking water of different countries. The results presented in this study may helpful in establishing a regulatory limit on radioactivity in drinking water in Bangladesh.View full abstractDownload PDF (3111K)
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