Comparison of commercial thermoluminescent readers regarding high-dose high-temperature measurements

Three different thermoluminescent measuring systems have been compared with respect to the differences in temperature profiles, spectral sensitivities, as well as characteristics for high intensities of TL light. The comparison was performed using the Harshaw 3500, Risø DA-20 and RA’94 TLD readers. The instruments were tested for the readouts of highly irradiated LiF:Mg,Cu,P (MCP) TL detectors, which require readout up to 550 °C, in case of doses exceeding 1 kGy. It was found that the Harshaw 3500 can be used, without any additional light attenuation, for the measurements of MCP detectors exposed to doses up to about 5 Gy. For the other two readers the upper dose limit is about 10 times lower. It was also found that the Harshaw 3500 shows the best thermal stability considering the peak maximum position. For the ultra-high doses the differences in the spectral characteristics of the applied optical filters and photomultipliers, in conjunction with an evolution of the MCP TL emission spectrum with increasing dose, significantly influence the shape of TL glow curves measured with the DA-20 reader. The detailed characteristic of the compared TLD readers at high-dose high-temperature range is discussed.     

电子束照射LiF薄膜有源沟道的宽带光致发光

用热蒸发在玻璃衬底上制备了多晶LiF薄膜，研究了由电子束照射产生的有源沟道的室温宽带光致发光特性，研究表明，室温下有源沟道F2和F3^ 色心具有较大的光增益和折射率增量，有望实现可见波段的可调谐有源光波导器件。     

Dosimetry for low temperature measurements using single and poly-crystals

The aim of this work was to study the behavior of a single and poly crystalline homemade solid state dosimeters (a) LiF co-doped with Mg, Cu and P, and (b) CaSO₄ doped with Dy. We analyzed the response of these dosimeters using thermoluminiscence. The dose-response at liquid nitrogen temperature was followed to observe the nature of the response.     

惰气熔融-红外光谱法测定7LiF中的氧含量

7LiF是制备熔盐堆冷却剂7LiF-BeF2熔盐的基础原材料,其杂质含量的多少与熔盐纯度及应用性能直接相关。采用惰气熔融-红外吸收法,建立了熔盐堆用7LiF中杂质氧含量测定的新方法。考察了不同助熔剂和加热功率等条件对7LiF中氧含量的影响,找到了较好的 7LiF中氧含量测定方法。在分析功率为2200W,用银舟做助熔剂,称样量为0.1 g的条件下对7LiF试样进行了测定,氧的相对标准偏差为2.9%;加标回收率为103-110%。结果表明,本测定方法易操作,速度快,能满足7LiF生产过程中的质量控制要求,为第四代先进核能反应堆用7LiF规模化制备提供了有力的技术支持。     

锂金属负极界面修饰及其在硫化物全固态电池中的应用

随着我国新能源产业的快速发展, 全固态电池由于其理论上的高能量密度和高安全性受到广泛关注, 而硫化物全固态电池具有离子电导率高的优势成为目前的研发热点, 但是金属锂负极的锂枝晶生长和与硫化物电解质之间的不稳定性严重阻碍了硫化物全固态电池的研发. 本工作在高温150 ℃下制备了均匀的LiF界面层来抑制金属锂负极/硫化物电解质之间的界面反应和锂枝晶. LiF/Li之间具有较高的界面能, 所以可以有效抑制锂枝晶的生长. LiNbO₂@LiCoO₂//Li₆PS₅Cl//LiF@Li (LNO@LCO//LPSCl//LiF@Li)全电池0.05 C, 0.1 C, 0.2 C和0.5 C倍率的正极放电克容量分别为138.4 mAh/g, 105.0 mAh/g, 80.3 mAh/g和60.4 mAh/g, 0.05 C循环50周后, 正极容量保持率为80.2%. 该方法为后续金属锂负极在全固态电池中的应用提供了新的方案.     

利用VISAR测量LY12铝在冲击压缩下的声速

 介绍了利用VISAR技术测量受冲击压缩LY12铝的高压声速的方法。平板对称碰撞实验在冲击波物理与爆轰物理实验室的二级轻气炮上进行，峰值应力约为20、32、55和71 GPa。每发实验中，VISAR同时使用三种条纹常数测量LY12铝和单晶LiF窗口的界面粒子速度剖面。从三种条纹常数计算的界面粒子速度剖面相互符合，完全一致。实验信号具有很高的信噪比，表明样品与窗口之间的界面连结和处理技术非常成功。这种测量技术不仅能够得到初始加载应力下的纵波声速，而且能够得到声速沿着卸载路径的变化。将声速的塑性段外推到初始冲击加载压力即得到该压力下的体积声速。LY12铝的声速测量结果与假定ργ为常数条件下用Mie-Grüneisen状态方程计算的结果符合得很好。     

9MeV电子直线加速器X射线测量

 高能工业CT采用9MeV电子加速器产生轫致辐射，利用高能X射线能够有效地穿透物质以及同物质对射线吸收和散射不同这一原理来检查物体内部缺陷或内部结构。加速器电子束的焦点、X射线的最高能量、X射线剂量及均匀性与工业CT成像的质量和速度密切相关；对探测器的电子线路部分进行的X射线屏蔽关系到探测器的使用寿命。X射线测量结果表明，所用9MeV电子直线加速器满足高能工业CT检测的要求。     

Oscillator strength of F2 − colour centres in LiF crystal

The absorption cross-section integral and the oscillator strength of the 960 nm absorption band due to F₂ ^– colour centres in LiF crystal is determined at room temperature from the absorption cross-section spectrum of the F₂ ^– centres obtained from saturable absorption studies. A comparison with previous results is made.     

氮分子激光照射增大了LiF:F_3~+心浓度

在液氮温度下采用氮分子激光(337nm)照射已着色的LiF晶体,能有效地产生高浓度的F_3~+心.文中详细地描述了着色LiF晶体中F_3~+心的产生方法、光谱特性及其形成机理.     

A CR-39 based thermal neutron dosimeter

Both chemically and electrochemically etched CR-39 detectors are used for the detection of fast neutrons. In practical situations, fast neutrons are always accompanied by thermal neutrons. Therefore, the response of the CR-39 based dosimeter has to be extended to thermal neutrons. To do so, a radiator/converter like LiF is introduced in front of the CR-39 detector and an optimum thickness of the LiF film is determined so that a response similar to that of the fast neutrons is achieved. Thin films of natural LiF were prepared and the response of the CR-39 detector was studied as a function of the film thickness.