X-ray induced Sm-ion valence conversion in Sm-ion implanted fluoroaluminate glasses towards high-dose radiation measurement
X-ray induced Sm-ion valence conversion in Sm-ion implanted fluoroaluminate glasses towards high-dose radiation measurement
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DOI：
10.1007/s10854-019-01212-4
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发表时间：
2019-04
期刊：
影响因子：
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通讯作者：
Farley Chicilo;C. Koughia;R. Curry;R. Gwilliam;Ruben Ahumada-Lazo;A. Edgar;D. Binks;D. Chapman
中科院分区：
文献类型：
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作者：
Farley Chicilo;C. Koughia;R. Curry;R. Gwilliam;Ruben Ahumada-Lazo;A. Edgar;D. Binks;D. Chapman
在微束放射治疗（MRT）的二维探测器的制造中，已经测试了Sm离子的离子注入。成功地将钐离子注入氟铝酸盐（FA）玻璃中。离子注入浓度为5 × 1015 ions/cm 2，注入能量为2 MeV。在注入之后，钐离子驻留在非常靠近玻璃表面的薄平面内，这预期对2D成像有益。注入后的光致发光（PL）谱表明，注入的Sm离子以Sm ~（2+）和Sm ~（3+）的形式存在。随后在玻璃化转变温度（475 °C）附近退火将所有Sm 2+离子转化为Sm 3+。在X射线照射下，已观察到Sm 3+到Sm 2+的部分转换，其可用作递送到样品中的X射线剂量的量度。QFRS（正交频率分辨光谱）测量的PL突出的Sm 3+和Sm 2+离子的发射表明，PL衰减与各种跃迁是在0.1至100毫秒的范围内（慢跃迁）。X射线照射也导致出现广泛和强烈的光致发光带与X射线诱导的结构缺陷的主机玻璃中确认在未植入的FA玻璃。在基质玻璃中空穴捕获中心的产生导致光生空穴的捕获，从而允许电子将Sm 3+转化为Sm 2+。缺陷相关的PL衰减信号被测量为在纳秒区域。这些不需要的缺陷相关的快速衰减信号已被分离慢Sm 2+和Sm 3+光致发光信号通过使用“异相”PL测量通过相位敏感的光电检测技术与调制的激发激光二极管和锁定放大器。总体而言，Sm离子注入的氟铝酸盐玻璃显示出在X射线强度的大动态范围（空气中800戈伊）的X射线照射下从三价形式的钐（Sm 3+）到二价形式（Sm 3+）的成功转化。
Ion implantation of Sm-ions has been tested in fabricating 2D detectors for microbeam radiation therapy (MRT). Sm-ions have been successfully implanted into fluoroaluminate (FA) glasses. The implantation concentration was chosen to be 5 × 1015ions/cm2and the ions were implanted at an energy of 2 MeV. After implantation, samarium ions resided within a thin plane very near the surface in the glass, which is expected to be beneficial for 2D imaging. Following implantation, photoluminescence (PL) spectra indicate that the embedded Sm-ions are in the form of Sm2+and Sm3+. Subsequent annealing around the glass transition temperature (475 °C) converts all Sm2+ions into Sm3+. Under X-ray irradiation, a partial conversion of Sm3+into Sm2+has been observed which may be used as measure of the X-ray dose delivered into the sample. QFRS (quadrature-frequency-resolved-spectroscopy) measurements on PL prominent emissions from Sm3+and Sm2+ions show that the PL decays associated with various transitions are in the 0.1 to 100 ms range (slow transitions). X-ray irradiation has led also to the appearance of broad and intense photoluminescence bands associated with X-ray induced structural defects in the host glass as confirmed in the unimplanted FA glasses. The generation of hole trapping centers in the host glass leads to the capture of photogenerated holes and thus allows the electrons to convert Sm3+to Sm2+. Defect related PL decay signals were measured to be in the nanosecond region. These unwanted defect related fast decaying signals have been separated from slow Sm2+and Sm3+photoluminescence signals by using an “out-of-phase” PL measurements through a phase-sensitive photodetection technique with a modulated excitation laser diode and a lock-in amplifier. Overall, the Sm-ion implanted fluoroaluminate glass shows the successful conversion from the trivalent form of samarium (Sm3+) to the divalent form (Sm3+) under X-ray irradiation over a large dynamic range of X-ray intensities (800 Gy in air).