کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1888173 | 1533416 | 2015 | 5 صفحه PDF | دانلود رایگان |
• Sensitivity changes of TLDs were studied after proton and gamma doses up to 30 Gy.
• Sensitivity loss of LiF:Mg,Ti and LiF:Mg,Cu,P is different for protons and γ-rays.
• A prolonged annealing time partly restores the sensitivity.
Two most common types of LiF-based thermoluminescent (TL) detectors LiF:Mg,Ti (natural Li: MTS-N) and LiF:Mg,Cu,P (natural Li: MCP-N) have been studied for sensitivity loss after 60 MeV proton and gamma rays (60Co) doses ranging between 0.5 and 30 Gy. The sensitivity (main peak area) of LiF:Mg,Ti was found to be reduced by almost 10% after the highest proton dose of 30 Gy with respect to the lowest dose of 0.5 Gy. The sensitivity loss was noticeable even after 5 Gy of protons. After gamma-ray exposures the sensitivity loss of LiF:Mg,Ti was smaller than after protons. LiF:Mg,Cu,P detectors show opposite effect: gamma-rays cause a stronger sensitivity loss than protons. The high-temperatures peaks of LiF:Mg,Ti decreased much more significantly than the main peak (by 40%). The decreased sensitivity may be partly (depending on the dose radiation type) recovered by application the extended annealing procedures: 400 °C/20 h for MTS-N and 10 min at 270 °C followed by 1 h at 240 °C for MCP-N. The observed changes of sensitivity are of importance for dosimetry in proton radiotherapy.
Journal: Radiation Measurements - Volume 74, March 2015, Pages 26–30