Al2O3:C、LiF:Mg,Ti、LiF:Mg,Cu,P对本底辐射的热释光响应比较

用Al2O3:C、LiF:Mg,Ti、LiF:Mg,Cu,P热释光剂量计(TLD)测量湛江市区本底辐射的热释光响应,以选取适合低辐射场辐射剂量测量的TLD。它们的最低响应剂量依次为Al2O3:C(1–2μGy)、LiF:Mg,Cu,P(约2μGy)和LiF:Mg,Ti(>10μGy)。Al2O3:C的热释光峰温较低,对较长时间段(>30 d)的累积剂量,存在较明显的热释光衰退,剂量响应曲线偏离线性;LiF:Mg,Cu,P和LiF:Mg,Ti的发光峰温较高,数年内都很稳定。综合考虑灵敏度和稳定性,LiF:Mg,Cu,P更宜于低辐射场的累积剂量测量。     

国产氟化锂片型热释光探测器性能比较研究

本文报道了对常用国产ＬｉＦ（Ｍｇ，Ｃｕ，Ｐ）和ＬｉＦ（Ｍｇ，Ｔｉ）两类片型热释光探测器的６种产品进行剂量学性能比较研究的结果。根据国家标准“个人和环境监测用热释光剂量测量系统”的技术要求和实际需求，比较了这几种探测器的热释发光曲线，相对灵敏度，探测阈，线性度，光子能量响应，一批的均匀性，重复性和稳定性等剂量学特性。文中还对ＴＬ探测器应用中的有关问题作了讨论。     

Comparison between the low temperature thermoluminescence spectra in annealed LiF:Mg,Cu, LiF:Mg,Cu,P and LiF:Mg,Cu,Si

Two strong thermal peaks in the wavelength range 220-420 nm have been detected at 128 and 140 K in LiF:Mg,Cu, at 123 and 135 K in LiF:Mg,Cu,P and at 125 and 133 K in LiF:Mg,Cu,Si, respectively. The origin of these main TL peaks is discussed in terms of defect perturbed H-F and V_K-e type recombination, respectively. The relative intensity between the two peaks in each sample and the emission spectra are dependent on the dopants.Annealing at 240-390 °C can modify the low temperature TL features, especially in those samples doped with three impurities. The low temperature data give some clues to select most favourable dopants for future LiF-type dosimeters.     

Neutron-gamma mixed field measurements by means of MCP-TLD600 dosimeter pair

In this paper, we compared the TL response of three types of thermoluminescence dosimeters, TLD600 (⁶LiF:Mg,Ti), TLD700 (⁷LiF:Mg,Ti) and MCP (LiF:Mg,Cu,P) after exposure to a n-γ mixed field in the fluence range of radiotherapeutic applications. Since a dosimeter pair is required to discriminate the two components of the mixed field, we analyzed the ability of each dosimeter pair to provide the fluence value in the mixed field. At this aim we performed a ⁶⁰Co-γ calibration and a neutron calibration for all three dosimeter types. Finally, a blind test was performed in order to analyze the accuracy of each dosimeter pair and we found that in this mixed field the fluence value obtained through the TLD600-MCP pair is as accurate as the value obtained through the most common TLD600-TLD700 pair.     

铜和磷杂质对LiF(Mg,Cu,P)热释光特性的影响研究

ＬｉＦ（Ｍｇ,Ｃｕ,Ｐ）和ＬｉＦ（Ｍｇ,Ｆｉ）热释光磷光体的ＴＬ特性的主要差别在ＴＬ灵敏度,奶量响应和热稳定性三个方面,其产生原因都与铜和磷杂质的掺入有关。ＬｉＦ热释光家族中,镁仍然是一种不可缺少的主要杂质,铜和磷杂质掺入后在磷光体中所形成的电子俘获中心和复合发光中心都与其他ＬｉＦ热释光磷光体有所不同,从而使其具有极高的ＴＬ灵敏性,异常的能量响应和较差的热稳定性。．     

Thermoluminescence and photoluminescence of cerium doped CaSO4 nanosheets

Thermoluminescence (TL) and photoluminescence (PL) characteristics of CaSO₄:Ce nanocrystalline prepared by hydrothermal method has been studied. Its TL glow curve contains three overlapping glow peaks at around 490, 505 and 521 K. Emission spectra band at 303 and 324 nm were observed for the orthorhombic phase of nanosheets. TL response of the prepared nanocrystalline to β and γ radiation was studied and the sensitivity of the nanosheets was found much more than that of analogous microcrystalline and is around 10 times higher than the well known high sensitive TL dosimeter LiF:Mg, Cu, P (GR-200) hot-pressed chips. TL kinetic parameters of this nanocrystalline are also presented.     

Track interaction in gamma- and charged-particle-irradiatedthermoluminescence dosimeters

The growth of thermoluminescence (TL) and optical absorption (OA) with absorbed dose was examined in LiF doped with Mg, as functions of both the linear energy transfer (LET) of the incident radiation and the impurity content of the samples. In addition, the TL growth curves were examined as a function of the heating rate during readout. The growth of TL as a function of dose is basically linear-supralinear-sublinear, but the precise character of the dose response function varies with the LET of irradiation, the Mg impurity content of the sample, and the heating rate during TL readout. the OA dose response is always linear-sublinear over the same dose ranges, even for those defect centers that are known to be involved in the TL process. The data indicate that the mechanisms responsible for the supralinear nature of the TL growth are operative during the TL readout phase rather than the absorption phase. A mathematical model is presented that qualitatively describes the results. The model is conceptually the same as the so-called track interaction model for high-LET irradiation, but the extension presented here makes it applicable to gamma-irradiated samples also     

The thermoluminescent properties of natural calcium fluoride for radiation dosimetry

The characteristics of natural calcium fluoride from Çiçekda?? Massif (Akçakent) in Turkey have been studied by analysing its thermoluminescence glow curve structure between 30 and 450 °C for the purpose of radiation dosimetry. A variety of thermoluminescence measurement regimes have been examined to determine the most effective and appropriate annealing temperature, heating rate and dose range for the proper and accurate use of this phosphorescent material. After a high temperature annealing as TL readings, optimum values for low temperature annealing and heating rate were obtained as 60 °C for 24 h and 1 °C s^?1, respectively. In the dose range of 0.5 Gy–1 kGy, the intensity of individual glow peaks and overall glow curve shape changed. The peak intensities of all glow curves located at 100 and 120 °C (overlapping considerably), and at 215 °C, at 310, 350 and 410 °C (overlapping) increase linearly with increasing ionizing radiation over a range of from 0.5 Gy to 10 Gy.     

NONLINEAR RESPONSES OF GAMMA —RAY DOSIMETERS

Either sublinear or supralinear responses of dosimeters to γ-ray can be described by a response function derived from statistical Poisson distribution.The characteristic parameters of the function determine linearity,sublinearity and supralinearlty in their responses.The experimental data of gamma dose-responses of alanine ESR dosimeters film dosimeters.LiF(Mg,Cu,P) and LiF(Mg,Ti) thermoluminescence dosimeters are used to test the response function.     

Tailoring the spring constant of Si nanorod structures using swift heavy ion irradiation

This study reports a post-deposition technique of engineering the mechanical properties of cantilever-like silicon nanorods by using swift heavy ion irradiation. Slanted silicon nanorods grown by glancing angle deposition technique on a patterned Si(1 0 0) substrate are irradiated by 100 MeV Ag⁺⁸ ions at a fluence of 10¹⁴ ions cm^?2. The average spring constant (k) of the nanorods determined by force–distance spectroscopy reduces to 65.6 ± 20.8 Nm^?1 post-irradiation as compared to 174.2 ± 26.5 Nm^?1 for pristine nanorods. Scanning electron micrographs show bending of the Si nanorods after irradiation. Micro-Raman and high-resolution transmission electron microscope studies on pristine and irradiated Si nanorods confirm the transformation of nanocrystalline regions present in pristine nanorods to amorphous phase on irradiation. This structural transformation and bending of the nanorods are responsible for the observed changes in the mechanical properties post-irradiation. The technique offers a simpler possibility of tailoring mechanical properties of nanostructures post-deposition by ion irradiation.     

Determination of self attenuation coefficient and relative TL efficiency of CaSO4:Dy, LiF:Mg,Cu,P and LiF:Mg,Ti TLDs - An alternate approach

Self attenuation of TL and relative TL efficiency of polytetra fluoro ethylene (PTFE) embedded CaSO₄:Dy disc, LiF:Mg,Ti (MTS) disc and LiF:Mg,Cu,P (MCP-N) chip were determined in the present study for photons of energy 10-34 keV. The relative TL efficiency was determined using an alternative approach in which ratio of experimental response and corrected theoretical response was used instead of measuring the absolute TL emission in photon counting mode. For CaSO₄:Dy disc, it was found that with increasing the proportion of CaSO₄:Dy phosphor in the disc, the light attenuation coefficient increases. The light attenuation coefficient of MTS disc and MCP-N chip was found to be 23.4 and 45.5 cm⁻¹, respectively. The relative TL efficiency in the photon energy range of 10-34 keV for MTS discs and MCP-N chips, evaluated in the present study matches well with the reported values in the literature.     

能隙中的电子运动

利用结晶固体的释光技术在BG2003释光谱仪上获得了MgSO₄、CaF₂、CaSO₄、LiF以及石英和LiF(Mg，P，Cu)剂量片热释光的释光光子能量。为固体能带理论的研究提供了具体数据。     

Thermoluminescence properties of isostructural K2YF5 and K2GdF5 crystals doped with Tb in response to α, β and X-ray irradiation

The thermoluminescence (TL) properties of isostructural fluoride K₂YF₅ and K₂GdF₅ crystals doped with Tb³⁺ of different concentrations have been studied in the temperature range from 30 to 500 °C after α, β and X-ray irradiation. Strongly different structures of TL glow curves following α or β irradiation have been found for Tb³⁺ doped K₂YF₅ for all studied concentrations of Tb³⁺ whereas for K₂GdF₅ crystals the different TL curves after α or β irradiation are detected only for heavily doped samples. On the other hand, all the studied materials show similar TL glow curves after β or X-ray irradiation. It has been discovered that K₂YF₅ doped with 1 at.% Tb³⁺ has TL radiation sensitivity to β irradiation of the same order as that of the well known TLD-100 (LiF:Mg,Ti) phosphor and much higher sensitivity to α irradiation. The TL mechanism in K₂YF₅ and K₂GdF₅ doped with Tb³⁺ is discussed by taking into account the TL emission spectra from irradiated samples, which are identical to the emission spectra of the Tb³⁺ ions in these hosts under photo-excitation, and the kinetics parameters obtained with the method of various heating rates.     

Effect of antimony incorporation on structural properties of CuInS2 crystals

CuInS₂ (CIS) single crystals doped with 1, 2, 3 and 4 atomic percent (at.%) of antimony (Sb) were grown by the horizontal Bridgman method. The effect of Sb doping on the structural properties of CIS crystal was studied by means of X-ray diffraction (XRD), energy dispersive X-ray analysis (EDAX), scanning electron microscopy (SEM) and PL measurements. X-ray diffraction data suggests that the doping of Sb in the CIS single crystals does not affect the tetragonal (chalcopyrite) crystal structure and exhibited a (1 1 2) preferred orientation. In addition, with increasing Sb concentration, the X-ray diffraction analysis show that Sb doped CIS crystals are more crystallized and the diffraction peaks of the CuInS₂ phase were more pronounced in particular the (1 1 2) plane. EDAX study revealed that Sb atoms can occupy the indium site and/or occupying the sulfur site to make an acceptor. PL spectra of undoped and Sb doped CIS crystals show two emission peaks at 1.52 and 1.62 eV, respectively which decreased with increasing atomic percent antimony. Sb doped CIS crystals show p-type conductivity.     

Nanoparticles of Al2O3:Cr as a sensitive thermoluminescent material for high exposures of gamma rays irradiations

Aluminum Oxide (Al₂O₃) doped with proper activators is a highly sensitive phosphor commonly used for radiation dosimetry using thermoluminescence (TL) technique. Nanoparticles of this material activated with Chromium (Cr) have been synthesized using the propellant chemical combustion technique and studied for their TL response. They were characterized by X-ray diffraction and scanning electron microscope. The synthesized material has spherical nanoparticles with grain size around 25 nm. These nanoparticles were exposed to heavy doses from γ-rays of ¹³⁷Cs. The TL glow curves show a prominent peak at around 474 K. This peak is found to be sensitive for high exposures of γ-rays and has linear response in the range of 100 Gy-20 kGy without showing saturation. This remarkable result suggests that Al₂O₃:Cr nanoparticles might be used for the dosimetry of food and seed irradiations.     

两批LiF(Mg、Cu、P)剂量计在环境中测量结果的差异与原因分析

两批LiF（Mg、Cu、P）热释光剂量计对大亚湾核电站环境监测的结果产生了15％的差异。本文实验分析了差异产生的原因,发现并验证这种差异是由于它们对宇宙射线的响应和自身本底的差别而造成的。     

两种LiF(Mg,Cu,P)片状探测器剂量学特性的比较研究

ＧＲ－２００Ａ与ＭＣＰ－Ｎ均为ＬｉＦ（Ｍｇ,Ｃｕ,Ｐ）片状探测器,现将ＧＲ－２００Ａ和ＭＣＰ－Ｎ在发光曲线,灵敏度,重复使用,抗潮湿性能,本底,探测阈,光敏等性能进行平行对比实验,其中ＧＲ－２００Ａ的灵敏度为ＭＣＰ－Ｎ的１．６倍;６次重复使用的结果ＧＲ－２００Ａ灵敏度无变化 ,ＭＣＰ－Ｎ灵敏度下降了２．６％,抗潮湿性能ＧＲ－２００Ａ更优于ＭＣＰ－Ｎ。     

The Transmission Line for the SPIDER experiment

The 100 keV Ion Source Test facility – Source for the Production of Ions of Deuterium Extracted from RF plasma (SPIDER) – is aimed to test the full scale prototype of the Ion Source for the ITER 1 MeV Neutral Beam Injector (NBI). The SPIDER facility requires the construction of a High Voltage Deck (HVD) and of a High Voltage Transmission Line (TL) respectively to host the Ion Source Power Supplies system polarized at 100 kV and to carry the power and signal conductors to the beam accelerator.In already existing NBI systems with beam energy above 100 keV, the TL is realized with the SF₆ Gas Insulated Line technology. In the SPIDER TL case, the presence of a large inner conductor (half meter diameter), would make the pressurized TL a complex and costly component; therefore a free air insulated solution has been proposed. The paper focuses on the design of this TL, which has to host inside the complex high potential (100 kV) inner electrode a number of power and measuring conductors and has to minimize the Electro Magnetic Interferences (EMI) produced by the frequent grids breakdowns.Finite Element (FE) analyses have been performed to verify the configuration from the electrostatic point of view, to evaluate EMI screening effectiveness and to assess the impact of the relatively high thermal dissipation of power conductors located inside the high potential electrode. Moreover, an experimental test campaign has been carried out on a TL mockup to validate the TL electrostatic configuration under DC voltage. Finally, the paper reports on the status of procurement activities for the Transmission Line.     

LiF（Mg,Cu,P）磷光体的X线衍射分析

对我们实验室制备的LiF(Mg,Cu,P)磷光体的X线衍射分析表明,磷光体制备过程中除生成掺有Mg,Cu和P杂质的LiF晶体外,还产生了焦磷酸锂(Li_4P_2O_7)和另外一种尚不知其组成的晶体。前者(Li_4P_2O_7)对磷光体的灵敏度的稳定性,后者对磷光体的能谱响应有一定影响。