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 หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Calibration of HPGe Gamma-Ray Planar Detector System for Radioactivity Standards) ผู้เขียน: Tidatrut Vichaidid, Thongchai Soodprasert, Teerasak Verapaspong สื่อสิ่งพิมพ์:pdf AbstractQuantitative analysis of radioactive materials using efficiency calibration of gamma ray high purity germanium planar detector system has been studied. Seven standard sources including Eu-152, Ba-133, Ag-110, Ho-166, Cs-134, Cs-137 and Co-57 were used for calibrating incident gamma ray energy to memory channels obtained by the new multi-channel analyzer which have been observed in the energy ranges from 25 to 1240 keV. The general equation of efficiency curve with varied source-todetector distance obtained at high energy range has shown up to 3% of uncertainties, k=2 when compared to low energy range of uncertainties up to 30% at 95% confidence interval when the dead time effect was also mentioned and corrected. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Comparative Study on U, Th and K Concentrations in Sediments at the Mae Moh Mine and Lam Phra Phloeng Dam) ผู้เขียน:Tidarut Vichaidid, Thongchai Soodprasert, Natnalin Sastri, Sasimonton Moungsrijun สื่อสิ่งพิมพ์:pdf AbstractThe concentration of uranium, thorium and potassium in sediment matrices, collected from the Mae Moh mine in Lampang Province, Northern Thailand and from the Lam Phra Phloeng Dam on Nakhon Ratchasima Province, Northeastern Thailand were determined using gamma spectrometry together with a neutron activation analysis technique (NAA). A high purity germanium (HPGe) welltype detector and digital spectrometer were calibrated by reference standard sources to obtain high efficiency for the quantitative evaluation. The concentration of uranium, thorium, and potassium of the Mae Moh mine samples achieved by these techniques was in the range 0.08 to 1.40 ppm, 4.60 to 6.70 ppm, and 0.80 to 1.50%, respectively and significantly lower than the samples collected from the Lam Phra Phloeng Dam which were in the range 2.28 to 2.96 ppm, 8.43 to 16.01 ppm, and 2.04 to 3.30%, respectively. It was shown that the concentration of naturally occurring radioactive materials (NORM) depended on the type and formation age of the sediment. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Determination of U, Th and K in Sediments and Fossil Collected from Mae Moh Mine Using Gamma-Ray Spectrometry and Neutron Activation Analysis (NAA)) ผู้เขียน:Tidarut Vichaidid, Thongchai Soodprasert, Natnalin Sastri, Chutima Oopathum, พิเชษฐ ลิ้มสุวรรณ สื่อสิ่งพิมพ์:pdf AbstractThe annual environmental dose in sediment and fossil shells matrices, collected from Mae Moh mine, Lampang province, Northern Thailand has been determined by using gamma spectrometry together with neutron activation analysis technique (NAA). This analysis technique was adopted by activating NBS standard reference materials (NBS SRM 2709: San Joaquin Soil) and sediment matrices at the same condition before measuring them at the specific time schedule. High Purity Germanium (HPGe) well type detector and spectrometer were calibrated to get efficiency ratio by reference standard sources. Most of natural radioactive elements are members of uranium, thorium and from non series nuclides, mainly potassium. The result concentration of uranium, thorium, and potassium in samples can be achieved by this technique and found to be in the range of 0.02 to 3.05 ppm, 0.04 to 11.00 ppm, and 0.01 to 1.53% respectively. The annual environmental dose is between 87-3000 mGy, depended on type of metrics, and can be specifically calculated and used for dating around the Middle Miocene time scale. |