A comparative study of optical and radiative characteristics of X-ray-induced luminescent defects in Ag-doped glass and LiF thin films and their applications in 2-D imaging

Abstract

We report novel disk-type X-ray two-dimensional (2-D) imaging detectors utilising Ag-doped phosphate glass and lithium fluoride (LiF) thin films based on the radiophotoluminescence (RPL) and photoluminescence (PL) phenomena, respectively. The accumulated X-ray doses written in the form of atomic-scale Ag-related luminescent centres in Ag-doped glass and F-aggregated centres in LiF thin films were rapidly reconstructed as a dose distribution using a homemade readout system. The 2-D images reconstructed from the RPL and PL detectors are compared with that from the optically stimulated luminescence (OSL) detector. In addition, the optical and dosimetric characteristics of LiF thin films are investigated and evaluated. The possibilities of dose distributions with a high spatial resolution on the order of microns over large areas, a wide dynamic range covering 11 orders of magnitude and a non-destructive readout are successfully demonstrated by combining the Ag-doped glass with LiF thin films. Toshio KUROBORI HIGHLIGHTSA novel disk-type Ag-doped glass and LiF thin film detectors based on the RPL and PL phenomena, respectively, were proposed.The capabilities of the 2-D dose images accumulated with a high spatial resolution and a wide dynamic range were demonstrated.The 2-D images reconstructed from the RPL and PL detectors were compared with that from the OSL detector. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 Center, Chiyoda Technol Corporation, 3681 Narita-cho, Oarai-machi, Ibaraki 311-1313, Japan c Pulstec Industrial Corporation, 7000-35 Nakagawa, Hosoe-cho, Kita-ku, Hamamatsu-shi, Shizuoka, 431-1304 Research Highlights ABSTRACTWe report novel disk-type X-ray two-dimensional (2-D) imaging detectors utilising Ag-doped phosphate glass and lithium fluoride (LiF) thin films based on the radiophotoluminescence (RPL) and photoluminescence (PL) phenomena, respectively. The accumulated X-ray doses written in the form of atomic-scale Ag-related luminescent centres in Ag-doped glass and F-aggregated centres in LiF thin films were rapidly reconstructed as a dose distribution using a homemade readout system. The 2-D images reconstructed from the RPL and PL detectors are compared with that from the optically stimulated luminescence (OSL) detector. In addition, the optical and dosimetric characteristics of LiF thin films are investigated and evaluated. The possibilities of dose distributions with a high spatial resolution on the order of microns over large areas, a wide dynamic range covering 11 orders of magnitude and a non-destructive readout are successfully demonstrated by combining the Ag-doped glass with LiF thin films.

Manipulation of Shallow-Trap States in Halide Double Perovskite Enables Real-time Radiation Dosimetry

“…30,31,32 To explore the potential possibilities of storage phosphor in halide perovskite, we doped a trace amount of Ag + in Cs 2 NaInCl 6 (named 0.005Ag + @Cs 2 NaInCl 6 , where 0.005 is the feeding ratio) because Ag is often used to adjust trapping centers in other storage phosphor materials. 33,34 Similar to pure Cs 2 NaInCl 6 , 0.005Ag + @Cs 2 NaInCl 6 maintains a nonemissive feature under UV excitation (Fig. 1B).…”

Research Progress of Radio-photoluminescence Materials and Their Applications

“…LiF 的 RPL 特性在 1976 年被 Levita 等 [21] 发现。 当 LiF 受到高剂量 γ 射线辐照时，由不同电子轨道 产生的 F 中心会聚集形成 F2 和 F3 + 中心(图 2(i))，并 在高剂量区(0.1~100 kGy)产生强烈的 RPL [31] 。基于 此， LiF 荧光粉逐渐被用于高剂量辐射监测。 此外， LiF 的有效原子序数(Zeff)近似于生物软组织(Zeff ≈ 7.13)，这也使其成为人体剂量学应用中最有吸引力 的材料之一。但由于其辐射灵敏度较低，目前仍无 法用于个人剂量监测 [7,[64][65] 。 图 2(h)给出了 LiF 在 X 射线(126 Gy)辐照后的 激发谱和发射谱，谱中显示出两个不同的 F 发光中 心，其中一个是 F3 + ，其发射峰位于 540 nm；另一 个是 F2，其发射峰位于 630 nm，且经 750 ℃预热 1 h，其峰值达到最高，二者都可以被 440 nm 的蓝光 激发 [31] 。此外，Mrozik 等 [65] 还报道了 LiF:Mg,Ti 和 LiF:Mg,Cu,P 两种材料的 RPL 特性，二者均可由蓝 光(460 nm)激发，并在 530 nm 附近观察到发射峰。 同时， 研究还将它们作为辐射探测器用于高剂量场， 最大辐射剂量检测范围高达 100 kGy。…”

“…事实上，有关 Cu 离子掺杂材料的辐射发光现 象早已被广泛研究，不过多集中在 TSL、OSL 和闪 烁发光，基于 RPL 特性的研究有限 [42] 。大多数 Cu 离子掺杂体系的 RPL 材料能够显示良好的化学耐 久性，但由于较低的辐射探测灵敏度，并不适用于 个人剂量监测，但在大剂量监测方面具有较大的应 用潜力。 Hashikawa 等 [42] (a) Schematic diagram of RPL/OSL/TSL general luminescence mechanism [13] ; (b) Excitation and emission spectra of Ag-PG [7] ; (c) Emission spectrum of Ag-PG under different doses of X-ray irradiation [52] ; (d) Excitation spectrum (pink dotted line) and emission spectrum of Ag-Rb glass before and after X-ray (10 Gy) irradiation [54] ; (e) Emission spectra of Ag-Nd co-doped phosphate glass at different radiation doses (310 nm excitation) [55] ; (f) Excitation spectrum (dashed line) and emission spectrum (solid line) of Ag-doped CsCl before and after X-ray irradiation [59] ; (g) Excitation and emission contour spectra of Al2O3:C,Mg irradiated by β-rays ( 90 Sr/ 90 Y) [63] ; (h) Excitation spectrum and emission spectrum of LiF after X-ray irradiation (126 Gy) [64] ; (i) RPL defect center in LiF, where F3 + is formed by three anionic vacancies capturing two electrons and F2 is formed by two anionic vacancies capturing two electrons [7] 随后， Hashikawa 等 [66] [68] 。Sm 离子是目前研究最多的镧系元 素， Sm 离子掺杂体系的 RPL 特性于 21 世纪初被发 现，但最初并没有用于辐射剂量学，而是用于高密 度的光学存储器 [7] 。直到 2011 年，Okada 等 [69][70] 才 将 Sm 离子掺杂材料用于 X 射线微束的剂量分布检 测。基于 Sm 离子掺杂的 RPL 材料体系有许多，主 要包括氟磷酸盐、氧化物、氟氧化物和卤化物等， 但实际只有少部分能够表现出 RPL 特性。特别需要 指出的是，Sm 离子掺杂材料具有极大的剂量范围 (mGy~kGy)，且大部分材料具有较好的辐射灵敏度 和可循环使用性等特点 [32,34,71] 。此外，Sm 离子掺 杂材料记录的 RPL 信号极其稳定，几乎不会衰退。 同时，辐照后产生的 RPL 信号具有极短的积聚时间， 因此适用于辐射剂量的实时监测。在 Sm 离子体系 的化合物中， Sm 离子在二价和三价下均具有稳定的 氧化态，但它们却拥有不同的电子架构。基态下的 [7,32,72]…”

A disk-type dose imaging detector based on blue and orange RPL in Ag-activated phosphate glass for 2D and 3D dose imaging applications

“…In addition, a comparative study has been performed of the 2D dose images acquired using Ag-activated phosphate glass based on the orange radiophotoluminescence (RPL) of atomic-scale Agrelated species and those acquired using LiF thin films based on the photoluminescence (PL) of F-aggregate colour centres (CCs) (Montereali et al, 1991), and the performances of the two techniques have been evaluated (Kurobori et al, 2014a). These disk-type detectors, with a diameter of 80 mm and a thickness of 1 mm, were rotated at a rate of 2400 rpm (40 Hz).…”