照射發光玻璃劑量計與熱發光劑量計量測輻射劑量之特性比較

A Comparative Study on Characteristics of Radiation Detectors between Radiophotoluminescent Glass Dosimeters and Thermoluminescent Dosimeters

許世明(Shih-Ming Hsu) ； 葉善宏(Shann-Horng Yeh) ； 林美秀(Meei-Shiow Lin) ； 陳為立(Wei-Li Chen)

《中華放射線醫學雜誌》 29卷6期 (2004/12) Pp. 323-330

摘要

本研究探討照射發光玻璃劑量計(radiophotoluminescent glass dosimeter)與熱發光劑量計之輻射偵測特性。
玻璃劑量計使用銀離子活化磷酸玻璃，作為量測X光及γ射線的偵檢器；此玻璃劑量計由11%的鈉、32%的磷、51%的氧、6.1%的鋁及0.17%的銀所合成。本研究所使用之熱發光劑量計為(上標 7)LiF:Mg, Ti；利用國家游離輻射標準實驗室的鈷-60、銫-137及X光機作為本研究之輻射源。此實驗比較玻璃劑量計與熱發光劑量計之輻射計讀值再現性、消光效應、增建效應、劑量線性度、能量依存度及角度依存度。
玻璃劑量計與熱發光劑量計相比，其具有更好的計讀值再現性（變異係數為0.48~0.63而TLD為1.50~1.90）、低的能量依存度（32keV至1250keV在-2~15.8%而TLD為-8~23%）、較佳的劑量線性度（0.01 mGy至500 mGy y=0.977x+00.1142而TLD為y=1.0528x-0.2236）、小的消光效應（30天小於1%而TLD為12%）及較大的角度依存度（-80°至80°為16.5%而TLD為6%）。
實驗結果顯示玻璃劑量計之計讀再現性、劑量線性度、能量依存度及消光效應皆優於熱發光劑量計。故玻璃劑量計是用於人員和環境劑量監控理想的劑量計之。

關鍵字

劑量 ； 輻射 ； 照射發光玻璃劑量計 ； 熱發光劑量計

並列摘要

The radiophotoluminescent glass dosimeters (RPLGD) and the thermoluminescent dosimeters (TLD) are two systems can be used for measurement of radiation dose of X-rays and gamma rays. This study compared the physical characteristics of the RPLGD and the TLD.
For RPLGD system, it used the flat silver activated phosphate glass. The RPL glass dosimeter material contains Na 11%, P 32%, O 51%, Al 6.1% and Ag 0.17% by weight. For TLD system, it used crystalline chips of (superscript 7)LiF:Mg, Ti. Gamma sources of (superscript 60)Co and (superscript 137)Cs as well as X-rays generator were borrowed from the National Radiation Standard Laboratory to irradiate the RPLGD and TLD. This study compared the physical characteristics of these two radiation measuring systems on reproducibility of readout value, fading effect, build-up effect, dose linearity, energy dependence and the angular dependence of irradiation.
In comparison to TLD, the RPLGD system has better reproducibility of readout values (coefficient of variations equaled 0.48~0.63 vs 1.50~1.90), lesser fading effect (1% vs 12% per 30 days), lower energy dependence (between -2 to 15.8% vs -8 to 23% for 32 keV to 1250 keV), better dose linearity (y=0.977x+0.1142 vs y=1.0528x-0.2236 for 0.01 mGy to 500 mGy), and higher angular dependence (-80°~P80° within 16.5% vs 6%).
According to the study on data reproducibility, fading effect, build-up effect, dose linearity, energy dependence and the angular dependence of irradiation, RPLGD is better than TLD for the dose range of X and gamma rays of personnel and environmental monitoring.

並列關鍵字

Dosimetry ； Radiation, measurement ； Radiophotoluminescent glass dosimeter ； Thermoluminescent dosimeter